Chronological List of Articles

SUMMARY:
This in vivo study evaluated the variation of tray fabrication (trays constructed with or without reservoirs) on the degree of color change of teeth and sensitivities associated with using a 15% carbamide peroxide bleaching agent for two hours once daily for 14 days.

Patients returned in one, two, three, six and 12 weeks. Color changes were evaluated by subjective shade matching, comparing clinical photographs and through measurements obtained using a color-measuring device. Subjects were asked to keep a daily record of any tooth and gingival sensitivity on the right and left side of their maxillary dental arch for three weeks.

Colorimeter data showed that teeth lightened with agent with reservoirs were significantly lighter than teeth lightened with the same agent without reservoirs. However, the amount of lightening was below the threshold of visual differentiation. Shade guide and slide photography data showed no significant differences between teeth lightened with agent with reservoirs compared to teeth lightened with the same agent without reservoirs. In addition, no significant differences in tooth and gingival sensitivity were found between the tray side with reservoirs and those without reservoirs.

SUMMARY:
This study determined the degradation of nine bleaching agents with different concentrations after two hours in vivo following the manufacturers’ recommendations. The nine carbamide peroxide products are 10%, 15% and 20% Opalescence, 10%, 15% and 22% Rembrandt and 10%, 16% and 22% Nite White Excel 2.

Each subject wore the tray with the bleaching agent for two hours on three separate occasions. The amount of remaining carbamide peroxide was determined after each use. Evaluation of remaining amount of carbamide peroxide was calculated by the US Pharmacopeia method.

The study showed that the total carbamide peroxide percent recovered was significantly higher for Opalescence products (47% to 54%) compared to Nite White (22% to 25%) and Rembrandt bleaching gels (15% to 16%). It concluded that this difference was mostly due to the use of facial reservoirs with Opalescence products, and also that whitening gel in trays with reservoirs and trays without reservoirs degraded at the same rate.

SUMMARY:
This study evaluated the marginal sealing ability of direct and indirect (inlay) resin composite restorations with three dentin bonding systems.

Forty-eight freshly extracted bovine incisor teeth were randomly assigned to four groups for bonding with Syntac Single-Component, Excite (Vivadent, Liechtenstein), ScotchBond Multi-Purpose Plus (3M Dental Products, St Paul, MN 55144, USA) and a control with no bonding agents. Class V cavities were cut in both buccal and lingual surfaces. The coronal half of each preparation was in enamel and the gingival half was in cementum or dentin. Half of the specimens in each group were restored with direct and the remainder with indirect technique.

The teeth were stored in 37°C water for 30 days, then thermocycled. After immersion in 0.5% basic fuchsin, the teeth were cut faciolingually and evaluated for dye penetration using a binocular stereomicroscope.

There was no significant difference among the bonding systems for either the direct or indirect technique or between the two techniques used for each system, however, the indirect technique showed significantly (p=0.001) less microleakage than the direct technique in control groups. All groups showed more leakage at the cementum margins except Excite with direct technique, where microleakage at the incisal and gingival margins was almost equal.

SUMMARY:
The clinical durability of some composite restorative materials may be significantly affected by cyclic temperature changes. This study investigated the effects of cyclic temperature changes on surface hardness of four commercial composite resins (Silux, Z100, Ariston and Surefil). Eighteen specimens of each material were divided into three treatment groups comprising a control and two different thermal cycling regimes. Control specimens were stored in distilled water at 35ºC for 178 hours. Thermal cycled specimens were stored in distilled water at 35ºC for 173 hours and subjected to five hours (300 cycles) of a thermal cycling regime consisting of the cycle ABAC, where A and B represent the fixed temperatures of 35ºC (28 seconds) and 15ºC (two seconds) and C, depending on the treatment group, either 45ºC or 60ºC (two seconds). All specimens were subsequently subjected to hardness testing (KHN) using a digital microhardness tester (load = 500 gf; dwell time = 15 seconds). Results were analyzed using ANOVA/Scheffe’s test (p<0.05). The effect of thermal cycling on hardness was material- dependent. While thermal cycling significantly increased the surface hardness of Z100 and Surefil, it significantly decreased the hardness of Ariston. The hardness of Silux was not significantly affected by cyclic temperature changes. For all treatment groups, Z100 was significantly harder than the other composite resins evaluated and Surefil was significantly harder than Silux and Ariston. For both thermal cycled groups, Silux was significantly harder than Ariston.

SUMMARY:
This study evaluated the effectiveness of the plasma arc curing (PAC) unit for composite curing. To compare its effectiveness with conventional quartz tungsten halogen (QTH) light curing units, the microhardness of two composites (Z100 and Tetric Ceram) that had been light cured by the PAC or QTH units, were compared according to the depth from the composite surface. In addition, linear polymerization shrinkage was compared using a custom-made linometer between composites which were light cured by PAC or QTH units.

Measuring polymerization shrinkage for two resin composites (Z100 and Tetric Ceram) was performed after polymerization with either QTH or PAC units. In the case of curing with the PAC unit, the composite was light cured with Apollo 95E for two (Group 1), three (Group 2), six (Group 3) or 2 x 6 (Group 4) seconds. For light curing with the QTH unit, the composite was light cured for 60 seconds with Optilux 500 (Group 5). The linear polymerization shrinkage of composites was determined in the linometer.

Two resin composites were used to measure microhardness. Two-mm thick samples were light cured for three seconds (Group 1), six seconds (Group 2) or 12 (2 x 6) seconds (Group 3) with Apollo 95E or they were conventionally light cured with Optilux 500 for 30 seconds (Group 4) or 60 seconds (Group 5). For 3 mm thick samples, the composites were light cured for six seconds (Group 1), 12 (2 x 6) seconds (Group 2) or 18 (3 x 6) seconds (Group 3) with Apollo 95E or they were conventionally light cured with Optilux 500 for 30 seconds (Group 4) or 60 seconds (Group 5). Twenty samples were assigned to each group. The microhardness of the upper and lower surfaces was measured with a Vickers hardness-measuring instrument under load. The difference in microhardness between the upper and lower surfaces in each group was analyzed by paired t-test. For the upper or lower surfaces, one-way ANOVA with Tukey was used.

For Tetric Ceram, the amount of polymerization shrinkage was lower when cured with the Apollo 95E for two or three seconds than when cured for six and 12 (2 x 6) seconds, or for 60 seconds with Optilux 500 (p<0.05). For Z100, the amount of linear polymerization shrinkage was lower when cured with the Apollo 95E for two, three and six seconds than for 12 (2 x 6) seconds with Apollo 95E or for 60 seconds with the Optilux 500 (p<0.05).

The results of the microhardness test indicated that there was no statistically significant difference in microhardness between groups for the upper surface. However, for the lower surface, when the composites were light cured with Apollo 95E for three seconds as recommended by the manufacturer, microhardness of the lower surface was usually lower than that of the upper surface and did not cure sufficiently.

Conclusively, when compared with conventional QTH unit, the PAC unit, Apollo 95E did not properly cure the lower composite surface when the layer thickness exceeded 2 mm. In addition, three seconds of curing time, which the manufacturer recommended, was insufficient for optimal curing of composites.

SUMMARY:
This study evaluated the effects of collagen removal on the microleakage of two single-bottle adhesive systems. Forty human third molars were selected and each received two root preparations. The roots were randomly assigned for restoration using Prime & Bond 2.1 (Dentsply Ltda, Petrópolis, RJ 90915, Brazil) or Single Bond (3M Dental Products, St Paul, MN 55144, USA). One root in each tooth was treated with 36% H3PO4 for 15 seconds and the other received an additional treatment with 10% NaOCl for 60 seconds to remove the collagen layer before adhesive was applied. All preparations were restored with Z100 restorative resin (3M Dental Products). The specimens were submitted to 5,000 thermal cycles (5-55°C) and stored in 37°C distilled water for one year. The specimens were then coated with a varnish except for 1 mm of tooth structure surrounding the restoration and immersed in 2% buffered methylene blue for four hours. After rinsing, the restorations were sectioned and two independent observers scored the microleakage at the interface between the restorative material and the tooth using an optical microscope at x45 magnification. The scores were submitted to Fisher’s Exact Test and the results showed that collagen removal significantly reduced microleakage for Prime & Bond 2.1 and had no effect on microleakage for Single Bond.

SUMMARY:
The study investigated the effectiveness of composite cure with pulse activation and soft-start polymerization. A light-cure unit (BISCO VIP, BISCO Dental Products, Schaumburg, IL 60193, USA) that allowed for independent command over time and intensity was used. The six light-curing modes examined were: Control (C)-400 mW/cm2 [40 seconds]; Pulse Delay I (PDI) -100 mW/cm2 [3 seconds] ® delay [3 minutes] ® 500 mW/cm2 [30 seconds]; Pulse Delay II (PDII) - 200 mW/cm2 [20 seconds] ® delay [3 minutes] ® 500 mW/cm2 [30 seconds]; Soft-start (SS) - 200 mW/cm2 [10 seconds] ® 600 mW/cm2 [30 seconds]; Pulse Cure I (PCI) – 400 mW/cm2 [10 seconds] ® delay [10 seconds] ® 400 mW/cm2 [10 seconds] ® delay [10 seconds] ® 400 mW/cm2 [20 seconds]; and Pulse Cure II (PCII) - 400 mW/cm2 [20 seconds] ® delay [20 seconds] ® 400 mW/cm2 [20 seconds]. Effectiveness of cure with the different modes was determined by measuring the top and bottom surface hardness of 2 mm thick composite (Z100) specimens using a digital microhardness tester (load=500 gf; dwell time=15 seconds). The effectiveness of cure of the bottom surface of the composite was also established by Fourier Transform Infrared (FTIR) spectroscopy using the KBr technique. Data obtained was analyzed using one-way ANOVA/Scheffe’s post-hoc test (p<0.05). No significant difference in top Knoops Hardness Number KHN was observed except for PDI and PDII. At the bottom surfaces, KHN obtained with the control was significantly greater than with PDII, SS and PCII. FTIR results ranked well with the hardness of the bottom surfaces. The absorbance ratio of carbon double bonds to aromatic ring obtained with the control group was significantly greater than with PDII and PCII. Effectiveness of the cure at the bottom surfaces of composites may be reduced by some pulse activation and soft-start polymerization regimens.

SUMMARY:
Many polishing protocols have been evaluated in vitro for their effect on the surface roughness of restorative materials. These results have been useful in establishing protocols for in vivo application. However, limited research has focused on the subsequent care and maintenance of esthetic restorations following their placement. This investigation evaluated the effect of five polishing protocols that could be implemented at recall on the surface roughness of five direct esthetic restorative materials. Specimens (n=25) measuring 8 mm diameter X 3 mm thick were fabricated in an acrylic mold using five light-cured resin-based materials (hybrid composite, microfilled composite, packable composite, compomer and resin-modified glass ionomer). After photopolymerization, all specimens were polished with Sof-Lex Disks to produce an initial (baseline) surface finish. All specimens were then polished with one of five prophylactic protocols (Butler medium paste, Butler coarse paste, OneGloss, SuperBuff or OneGloss & SuperBuff). The average surface roughness of each treated specimen was determined from three measurements with a profilometer (Surface 1). Next, all specimens were brushed 60,000 times at 1.5 Hz using a brush-head force of 2 N on a Manly V-8 cross-brushing machine in a 50:50 (w/w) slurry of toothpaste and water. The surface roughness of each specimen was measured after brushing (Surface 2) followed by re-polishing with one of five protocols, then final surface roughness values were determined (Surface 3). The data were analyzed using repeated measures ANOVA. Significant differences (p=0.05) in surface roughness were observed among restorative materials and polishing protocols. The microfilled and hybrid resin composite yielded significantly rougher surfaces than the other three materials following tooth brushing. Prophylactic polishing protocols can be used to restore a smooth surface on resin-based esthetic restorative materials following simulated tooth brushing.

SUMMARY:
This study compared the surface finish of a new hybrid aesthetic restorative material (Reactmer) over time to four different types of existing materials. The latter included a composite (Spectrum TPH), a compomer (Dyract AP) and conventional (Fuji II) and resin-modified glass ionomer cements (Fuji II LC). Six specimens of each material were fabricated and stored in distilled water at 37¼C for one week. The materials were subsequently finished with a series of Sof-Lex contouring and polishing disks. The average surface roughness (Ra, µm) of each specimen was measured at three days and three months by a surface profilometer. Storage medium was distilled water at 37¼C during the hiatus periods. Data was analyzed by ANOVA/Scheffe's and independent samples t-tests at significance level 0.05. At both time periods, Fuji II and Fuji II LC were significantly rougher than Spectrum, Dyract and Reactmer. For all materials, surface roughness at three days was not significantly different from that at three months. The surface finish of the giomer (Reactmer) was significantly better than conventional/resin-modified glass ionomer cements and comparable to the composite and compomer evaluated. The quality of surface finish for all materials was not significantly affected by long-term storage in water.

SUMMARY:
This study evaluated the effect of polishing after one-day storage in water on the gap formation around a Class V restoration completely bordered by enamel (coronal cavity) using one resin-modified glass ionomer, one compomer and one conventional glass ionomer as a control. The study also examined gap formation of these materials in two different cervical restorations—a cervical cavity incisally bordered by enamel and cervically bordered by dentin and a root surface cavity completely bordered by dentin.

When the specimens of the two types of glass-ionomer material were polished immediately after the setting procedure, 100-120 gaps around the coronal restorative cavity were observed. In contrast, only 10-20 gaps were observed when the specimens were polished after one-day storage. Significant differences in the two glass-ionomer restorative materials were observed between immediate polishing and polishing after one-day storage. The compomer not show this pattern.

Restorations placed in enamel/dentin and all- dentin gave results similar to those in all-enamel.

SUMMARY:
This study compared the whitening effect of three bleaching agents on the teeth of rats and demonstrated differences in bleaching where dentin was exposed or enamel was thin. Thirty Albino rats were peritoneally injected with tetracycline solution daily for two weeks. Thirty-two disc-shaped specimens were cut from the crowns of incisors removed from sacrificed rats and were irradiated with UV light for 16 hours. Sections were stored in saline. Eight sections served as controls and were not bleached. Three bleaching agents (Opalescence, Rembrandt and Nite White) were applied to eight specimens each, five times a day for two weeks, and images of the sections were recorded at the following times: before bleaching (baseline), day 1, day 3, day 5, day 7, day 9, day 11 and day 14. Mean colors to demonstrate any change (DE) from baseline for each time period were as follows: control—9.78 (baseline), 9.17, 9.36, 9.65, 9.40, 9.99, 10.57, 11.36; Opalescence—10.08, (baseline) 7.63, 6.72, 6.04, 5.10, 4.87, 4.89, 4.27; Rembrandt—9.83 (baseline), 11.27, 9.55, 8.36, 7.75, 6.94, 7.11, 7.04; Nite White—10.44 (baseline), 9.92, 7.58, 6.80, 5.45, 5.05, 4.73, 4.01. All bleached teeth were lightened (p<.01).

Another 56 tetracycline-stained rat incisors were UV irradiated for three days. Three different penetration depths were tested: penetration through lingual dentin and labial enamel (DN group), penetration through labial enamel only (RE group) and penetration through labial enamel covered with 1.0 mm human enamel (HE group). Specimens were bleached with Opalescence for one hour five times a day for one week or four weeks. A control group of unbleached teeth was also examined. Results (DE) were as follows: control—11.67; 1-week DN—13.55; 1-week RE—12.80; 1-week HE—12.07; 4-week DN—7.48; 4-week RE—7.50; 4-week HE—11.69. The color change in the 4-week DN and the 4-week RE groups showed the greatest reduction (p<.01).

SUMMARY:
Controversy regarding patient exposure to mercury from dental amalgam is more than 150 years old. Researchers continue to investigate the amount of mercury vapor released from amalgam both in vivo and in vitro. In this investigation, an in vitro testing method previously described in the literature was used to quantify the effect of operator-controlled variables on mercury release from dental amalgam. The variables tested were alloy morphology (spherical, admixed or atomized irregular particle), operator skill (inexperienced, novice and expert), operator technique (overfill and evenly fill) and cavity design (standard Class I, double volume and double surface area). Preparations fabricated in sections of acrylic rod were filled with dental amalgam, placed in 25 mL glass bottles and sealed. Mercury vapor concentrations were measured using a Jerome M-411 at specified times. Standardized mean concentrations for each time and total mercury released over time were calculated and analyzed with ANOVA and Tukey HSD. Statistically significant differences (a = 0.05) were identified for all variables tested. Total mercury vapor release was consistently found to be greater for admixed as compared to spherical amalgam. Amalgam restorations prepared by an inexperienced operator demonstrated statistically less mercury vapor than a novice or experienced clinician for both spherical and admixed morphologies. A statistically significant difference in mercury vapor using different condensation and carving techniques was found for the spherical amalgam but not for the admixed material. Restoration design demonstrated significant differences in total mercury vapor dependent on volume and exposed surface area of the amalgam restoration. In this in vitro investigation, mercury vapor release from amalgam was dependent on alloy morphology, operator experience, operator technique and restoration design.

SUMMARY:
This study investigated the influence of pulse activation and soft-start polymerization regimens on the post-gel shrinkage of a visible light-activated composite resin (Z100). A light-cure unit (BISCO VIP) that allowed for independent command over time and intensity was used. The six light-curing modes that were examined include: Control (C)–400 mW/cm2 [40 seconds]; Pulse Delay I (PDI)–100 mW/cm2 [3 seconds], delay [3 minutes], 500 mW/cm2 [30 seconds]; Pulse Delay II (PDII)–200 mW/cm2 [20 seconds], delay [3 minutes], 500 mW/cm2 [30 seconds]; Soft-start (SS)—200 mW/cm2 [10 seconds], 600 mW/cm2 [30 seconds]; Pulse Cure I (PCI)—two 400 mW/cm2 [10 seconds] and one 400 mW/cm2 [20 seconds] pulses with 10 seconds interval between; and Pulse Cure II (PCII)—two 400 mW/cm2 [20 seconds] pulses with 20 seconds interval between. A strain-monitoring device measured the linear polymerization shrinkage associated with the various cure modes during and post light polymerization up to 60 minutes. Five specimens were made for each cure mode. Data was analyzed using one-way ANOVA and Scheffe’s post-hoc test at significance level 0.05. Post-gel shrinkage associated with PDI was significantly lower than with PDII, SS and PCI immediately post light-polymerization. At one-minute post light polymerization, PDI had significantly lower shrinkage compared to PDII and SS. Significant differences in shrinkage were observed between PDI and SS only at 10, 30 and 60 minutes. At all time intervals, no significance in post-gel shrinkage was observed between the control and all-pulse activation/soft-start polymerization regimens.

SUMMARY:
Single application bonding systems have recently been developed in an effort to simplify and shorten bonding procedures. This study compared their bonding ability to enamel and dentin. Four commercial single application systems, Reactmer Bond (Shofu Inc), One-Up Bond F (Tokuyama Co), AQ Bond (Sun Medical Co, Japan) and Prompt L-Pop (ESPE, Germany) were used. F2000 compomer (3M Dental Products, St Paul, MN 55144, USA) was used as a control material. Bovine mandibular incisors were mounted in self-curing resin and the facial surfaces were ground to expose either enamel or dentin. Restoratives were bonded after adhesive application to tooth surface according to the manufacturer’s instructions. Fifteen samples per test group were stored in 37°C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/minute. Statistical analysis was accomplished with a one-way ANOVA followed by the Duncan test (p<0.05) were done. The enamel bond strengths of the newly developed one step bonding systems were not significantly different from the compomer except for Prompt L-Pop, which showed the highest value. The dentin bond strengths of single application bonding systems did not differ from the compomer. The results of this study suggest that the adhesive properties of the newly developed single application bonding systems were comparable to a compomer restorative.

SUMMARY:
Food impaction occasionally occurs in interproximal sites even though the contacts are tight. In this study of 14 patients with food impaction involving tight contacts, the lack of adequate food escape grooves was common to all 14 sites. Uneven marginal ridges and prominent opposing cusps were less common and, together, made up slightly more than half of the contact sites. An occlusal adjustment technique to create adequate food escape grooves, as well as reduce prominent opposing cusps and correct uneven marginal ridges, completely eliminated food impaction in all but one site. This site achieved an 80% reduction in food impaction. Based on the results of this retrospective study, the lack of adequate food escape groves in teeth adjacent to a contact point manifesting food impaction appears to be the primary factor. Creating food escape grooves adjacent to the marginal ridges eliminates, or nearly eliminates, food impaction in tight contact sites.

Dr Wendell A Foltz

Dr Melvin R Lund

SUMMARY:
Because dental fissures may serve as reservoirs for mutans streptococci, preventive measures should be taken to control microbial concentrations at these sites. This study estimated the influence that sealing permanent first molars would have on the levels of mutans streptococci and lactobacilli in saliva of healthy seven-year-old schoolchildren. Permanent first molars were sealed in 31 children without caries (NC group) and in 32 children with caries (C group). None of the children had caries in their permanent first molars. Conventional methods were used to count mutans streptococci and lactobacilli in saliva before applying the sealant and again at 4 and 12 weeks after application. Baseline counts of lactobacilli and mutans streptococci were significantly higher in the C group. A significant reduction in mutans streptococci was observed in the NC group at 4 and 12 weeks. It was concluded that fissure sealants in permanent first molars can help reduce salivary levels of mutans streptococci in children without caries.

SUMMARY:
This study evaluated the clinical performance and appearance of a resin-modified glass ionomer and a resin composite over one year. Thirty-seven pairs of restorations of Fuji II LC and Z250/Single Bond were placed in caries-free cervical erosion/abfraction lesions without tooth preparation. Restorations were clinically evaluated at baseline and 6 and 12 months, using modified Ryge/USPHS criteria. No significant difference (p>0.05) was observed in performance of both materials, although retention of the Z250 restorations was below the minimum specified in the ADA Acceptance Program for Dentin and Enamel Adhesives. Little difference in the restorations' appearance was observed.

SUMMARY:
Ninety-one Icelandic practicing dentists (51% response rate) provided information related to the reasons for placement and replacement of 8,395 restorations and 741 sealants in 5,997 patients. Information included the patient's gender and age, the clinician's gender and experience in years since graduation, the defined criteria for replacement of restorations, the estimated past use of material in five-year increments and the records of 100 consecutively placed restorations. The materials used include composite (52.7%), amalgam (29.2%), glass ionomer (9.5%), resin-modified glass ionomer (7.1%) and other materials (1.4%). Although material selection was independent of the clinician's gender, female patients received more composite and fewer amalgam restorations than their male counterparts. Reasons for placing restorations comprised replacement of failed restorations (47.2%), primary caries (45.3%) and non-carious defects (7.5%). Secondary caries was the main reason for replacement for all types of restorations. Chi square analysis related to the dependence between the reasons for replacement and clinician's experience showed that more experienced clinicians recorded a lower frequency of secondary caries than less experienced ones (p<0.0001), while the diagnoses of discoloration and fracture of restorations increased with the clinicians' experience (p<0.0001).

SUMMARY:
This study investigated the penetrability of dentinal tubules in cavity walls lined with different dentin bonding systems. Occlusal Class I cavities were prepared in 93 premolars. The cavities in the control group had an intact smear layer without a lining, while those in the experimental group were lined with Gluma CPS, Scotchbond Multi-Purpose Plus or One-Step. The penetrability of the dentinal tubules was tested with a dye (basic fuchsin) or bacteria (S faecalis) immediately after adhesive lining and after one-month storage in water at 37¡C. Some of the lined samples were sectioned and examined under the SEM.

In some samples in the experimental group, the dye penetrated to the pulp and bacteria up to 125 µm into the dentinal tubules immediately after lining. The Kruskal Wallis ANOVA and Tukey test showed the depth of dye and bacterial penetration to be significantly less in teeth with bonding systems than those in the control group (p<0.05). However, there was no statistically significant difference between the control and experimental groups after storage in water (p>0.05). SEM examination showed that the hybrid layer and resin tags were present in the cavity walls immediately after lining but absent after storage in water. Therefore, adhesive linings under the experimental conditions were ineffective in preventing dye or bacterial penetration of the dentinal tubules.

SUMMARY:
The advantage of using ceramic inserts is to prevent major drawbacks of composite resins such as polymerization shrinkage, wear and microleakage. This in vitro study evaluated the marginal adaptation of two approximal ceramic insert systems after cementation to the cavities opened with ultrasonic tips. Proximal cavities with margins in enamel were prepared in 20 intact molars using ultrasonic tips (SONICSYS approx tips [microtorpedo size #2 and #3]; Siplus Instrument approximal [U-shaped]). Inserts of similar sizes (n=10) from two systems corresponding to the ultrasonic tips were placed in the cavities (SONICSYS Inlay; SDS-Inlay system), one on the mesial side and the other on the distal side of the same molar. Following cementation and thermocycling (5000 cycles, between 5-55¼C), cement thickness was measured at the buccal, lingual walls and pulpal floors of the proximal boxes under light microscope (x150). The mean cement thickness values recorded for SONICSYS inserts #2 (25 µm) was not significantly different (p>0.05) from that of SDS inserts of similar size (26 µm). There was a significant difference (p<0.05) in cement thickness values between SONICSYS #3 inserts (34 µm) and SDS inserts of similar size (23 µm). Comparison of mean values between the ceramic insert systems examined revealed that marginal adaptation was better at the buccal and lingual proximal walls than those at the pulpal floor in the SDS system, however, there was no difference for SONICSYS at both sizes. Ceramic inserts placed in cavities prepared with ultrasonic tips provide clinically acceptable marginal quality.

SUMMARY:
This study investigated the effects of in-office tooth whiteners on the hardness of hybrid (Spectrum TPH), polyacid-modified (Dyract AP), PRG (Reactmer) composites and a resin-modified glass ionomer cement (Fuji II LC). Twenty-seven specimens of each material were fabricated, randomly divided into three groups of nine and treated as follows-Group 1: stored in distilled water at 37¡C for three weeks (control); Group 2: treated with 35% carbamide peroxide (Opalescence Quick) for 30 minutes/week for three weeks; Group 3: treated with 35% hydrogen peroxide power bleach (Opalescence Xtra) for 30 minutes/week for three weeks. For Groups 2 and 3, specimens were stored in distilled water at 37¡C during the hiatus periods. The treated specimens were subsequently subjected to microhardness testing (load = 500gf; dwell time = 15 seconds). Results were analyzed using ANOVA/Scheffe's test (p<0.05). For all treatment groups, Spectrum was significantly harder than the other materials and Reactmer was significantly harder than Dyract and Fuji II LC. The effects of in-office tooth whiteners on microhardness were material-dependent. No significant difference in hardness was observed between treatment groups for Dyract and Reactmer. For Spectrum and Fuji II LC, specimens treated with Opalescence Quick were significantly harder than those treated with Opalescence Xtra. No significant difference in hardness was observed between the control and bleached groups for all materials. The hardness of resin-modified glass-ionomer cements, hybrid, polyacid-modified and PRG composites is therefore not significantly affected by the use of 35% carbamide peroxide and 35% hydrogen peroxide in-office tooth whiteners.

SUMMARY:
This study investigated the influence of zinc-oxide eugenol (ZOE) temporary restorations on microleakage in composite restorations. Class V cavities were prepared on the buccal surfaces of 32 freshly extracted, non-carious human premolars. The teeth were randomly divided into four groups of eight teeth. Specimens in Group 1 (control) received no temporary restoration. Group 2 and 3 specimens were covered with IRM (Type III ZOE cement) mixed at powder:liquid (P:L) ratio of 10g: 1g and 10g: 2g, respectively. Specimens in Group 4 were covered with polycarboxylate cement (eugenol-free) mixed at a P:L ratio of 2.85g:1g. The temporary restorations were removed mechanically with an ultrasonic scaler after one week storage in distilled water at 37¼C. The preparations were washed and restored with Scotchbond Multi-Purpose Plus and Z100 according to manufacturers' instructions. The restorations were finished, thermally stressed for 400 cycles and subjected to dye penetration testing. Results were analyzed using Kruskal-Wallis and Mann-Whitney tests at a significance level of 0.05. At both enamel and dentin margins, the microleakage associated with Group 3 was significantly greater than for Groups 1, 2 and 4. For Groups 1 and 4, leakage at the dentin margins was significantly greater than in enamel margins. For the groups pre-treated with IRM, no significant difference in dye penetration scores was observed between enamel and dentin. Pre-treatment with IRM mixed at a P:L ratio of 10g: 2g significantly increased microleakage and is not recommended clinically.

SUMMARY:
This study investigated the effects of cyclic temperature changes on the water sorption and solubility of four commercial composite resins (Silux Plus, Z100, Ariston pHc and Surefil). The methodology was based upon ISO 4049 procedures with modifications for specimen dimension and thermal-cycling. Eighteen disc specimens (10 ± 1 mm diameter and 1 ± 0.1 mm thick) were made for each composite and randomly divided into three groups. The specimens were stored in a desiccator maintained at 35 ± 1¡C until a constant mass was achieved and treated as follows: Group 1-stored in distilled water at 35¼C for 178 hrs; Group 2-stored in distilled water at 35¼C for 173 hours and subjected to five hours of thermal-cycling with an upper temperature of 45¼C; and Group 3-stored in distilled water at 35¼C for 173 hours and subjected to five hours of thermal-cycling with an upper temperature of 60¼C. Mass after treatment was measured and specimens were re-conditioned to constant mass. The volume of the specimens was obtained and water sorption/solubility calculated. Data was analyzed using factorial ANOVA/Scheffe's post-hoc test at significance level 0.05. The effects of thermal-cycling on water sorption was material dependent. Thermal-cycling at an upper temperature of 60¼C significantly increased water sorption of Silux Plus. A significant increase in water sorption was also observed when Z100 was thermal-cycled at an upper temperature of 45¼C. The water sorption of Ariston pHc and Surefil was not affected by thermal- cycling. Thermal-cycling did not affect the solubility of all composites. For all treatment groups, Surefil had significantly lower water sorption than the other composites evaluated. The water sorption of Z100 and Surefil was significantly lower than Silux Plus and Ariston pHc.

SUMMARY:
A laboratory study evaluated the influence of a dentin desensitizer (D/Sense 2) on the microtensile bond strength of two adhesive systems: a self-etching primer (Bistite II SC) and a one-bottle adhesive (Prime & Bond 2.1). Sixteen crown dentin discs were obtained from extracted sound human third molars. Dentin surfaces were ground with 600 grit silicon carbide (SiC) abrasive papers to produce a standardized smear layer. Teeth were randomly divided into four groups (n=4). G1-D/Sense 2 + Prime & Bond 2.1; G2-D/Sense 2 + Bistite II SC; G3- and G4-dentin surfaces were bonded with Prime & Bond 2.1 and Bistite II SC, respectively, with no previous treatment with D/Sense 2. Eight mm high resin composite crowns (TPH Spectrum) were incrementally built-up on the treated surfaces. One sample from each group was prepared for evaluation of the hybrid layer on SEM. The specimens for the microtensile test were serially sectioned perpendicular to the adhesive layer to obtain 1 mm2 bounded sticks. Then, each stick was submitted to the microtensile test performed at a 0.5 mm/min crosshead speed. One-way ANOVA and Tukey test showed statistically significant differences among the groups (p<0.05). Values in MPa were: G1-17.85; G2-9.88; G3-35.16; G4-15.57. Based on the results of this study, it can be concluded that the D/Sense 2 desensitizer decreased the bond strength of Prime & Bond 2.1 and Bistite II SC bonding systems.

SUMMARY:
This study compared the surface finish of a new hybrid aesthetic restorative material (Reactmer) over time to four different types of existing materials. The latter included a composite (Spectrum TPH), a compomer (Dyract AP) and conventional (Fuji II) and resin-modified glass ionomer cements (Fuji II LC). Six specimens of each material were fabricated and stored in distilled water at 37¼C for one week. The materials were subsequently finished with a series of Sof-Lex contouring and polishing disks. The average surface roughness (Ra, µm) of each specimen was measured at three days and three months by a surface profilometer. Storage medium was distilled water at 37¼C during the hiatus periods. Data was analyzed by ANOVA/Scheffe's and independent samples t-tests at significance level 0.05. At both time periods, Fuji II and Fuji II LC were significantly rougher than Spectrum, Dyract and Reactmer. For all materials, surface roughness at three days was not significantly different from that at three months. The surface finish of the giomer (Reactmer) was significantly better than conventional/resin-modified glass ionomer cements and comparable to the composite and compomer evaluated. The quality of surface finish for all materials was not significantly affected by long-term storage in water.

SUMMARY:
This in vitro study evaluated the effect of metal alloys on three-body wear resistance of enamel and dentin, and vice versa. Three-body wear of human enamel, dentin, a soft gold alloy (BiOcclus Inlay), a CoCr alloy (Remanium 2000), a resin cement (Variolink II) and a zinc oxide phosphate cement (Harvard) was investigated using the ACTA-machine. Sample chambers of eight sample wheels were prepared with pure materials or combinations of human tooth substance, alloys and cement, simulating an inlay-like situation. After 100,000 and 200,000 cycles in a millet suspension with a spring force of 20 N, the amount of abraded material was profilometrically measured and evaluated by 3D surface data analysis. After 200,000 cycles, the materials demonstrated a mean loss of 0.41 µm for CoCr, 51 µm for gold, 57 µm for enamel, 164 µm for dentin, 79 µm for Variolink and 369 µm for Harvard. Using ANOVA and the Games-Howell-test, resin cement, enamel and gold were a subset not shown to differ, as was zinc phosphate cement and dentin. CoCr demonstrated the least wear and differed significantly from all materials. Enamel wear was significantly reduced in mixed chambers with CoCr and gold after 200,000 cycles compared to enamel in pure chambers. In summary, a soft gold alloy can be recommended for inlays when considering three-body abrasion since the wear rate of the "soft" gold alloy corresponded to that of human enamel.

SUMMARY:
This study assessed the finishing and polishing of a hybrid composite and a glass-ceramic. Ninety Tetric specimens were divided into three groups of 30 specimens and finished with three different finishing procedures. The 30 specimens were subsequently subdivided into six groups of five and polished using the following polishing systems: Sof-Lex disks, the Ceramiste kit, a diamond polisher, Diafix-oral, the MPS gel and the Politip system. Seventy-five IPS-Empress specimens were divided into groups of 25 and finished with three different procedures. The 25 specimens were then subdivided into five groups of five and polished with the same systems, except for the Politip technique. The polished surfaces were evaluated quantitatively by laser stylus profilometry with respect to Ra and profile-length-ratio (LR). Qualitative assessment was carried out by SEM. Quantitative results were examined statistically by one- and two-way Anova and LSD test with significance level of 0.05. The lowest roughness on composite specimens was achieved by the MPS gel and Diafix after finishing according to FM 3 and FM 2. With respect to all methods used, there were no significant differences among the five methods with the lowest Ra-values. The ceramic specimens were able to be polished to lower roughness values (p<0.001 for LR). The best results on ceramic surfaces were achieved with the MPS system after finishing according to FM 3 and FM 2. There were no significant differences among the three methods with the lowest Ra-values and the glazed surface.

SEM evaluation largely confirmed the quantitative results. Composite specimens exhibited signs of selective resin matrix removal when the Ceramiste system or the Politip system were used.

SUMMARY:
This study evaluated the influence of seven commercially available bonding agents on the flexural properties of an Ultra High Molecular Weight Polyethylene (UHMWPE) Fiber-Reinforced Composite (FRC). Nine groups (n=10 per group) of flexural strength specimens were prepared from an indirect composite reinforced with UHMWPE fiber and cured according to manufacturers' instructions (Groups A to I). Group I was a fiber-reinforced negative control without any bonding agent resination. A tenth group (Group J) was a positive control group prepared using indirect composite alone. The fiber reinforcement material for Groups A to H was resinated with one of the seven different bonding agents. Group H used the same bonding agent as for Group G specimens. However, the fiber was silanized before bonding agent application for Group G specimens. Specimens were stored wet for 24 hours at 37¡C before measuring flexural strength and modulus in three-point bend at a crosshead speed of 1 mm/minute. Scanning Electron Microscopy (SEM) was employed to assess the fiber-resin interface of representative samples. The mean (SD) flexural strength of the test groups impregnated by the bonding agents ranged from 169 (37) to 266 (39) MPa. Statistical analysis of the flexural strength data using one-way ANOVA revealed significant (p<0.05) differences between the test groups. There was catastrophic fiber/composite failure in the positive control group that had a mean flexural strength of 75 (8) MPa. Silane pre-treatment of UHMWPE fiber before impregnation with the bonding agent significantly reduced the flexural strength (p<0.05).

SUMMARY:
This study measured the gap that resulted from polymerization shrinkage of seven restorative resin composites after curing by three different methods. Contraction behavior, according to the specimen region, was also characterized. The materials used for this study were Alert (Jeneric/Pentron, Wallingford, CT 06492, USA), Surefil (Dentsply Caulk, Milford, DE 19963, USA), P60 (3M Dental Products, St Paul, MN 55144, USA), Z250 (3M), Z100 (3M), Definite (Degussa-HŸls, Hanau, Germany) and Flow-it (Jeneric/Pentron). The composite was placed in a circular brass mold 7 mm in diameter and 2 mm in height. Photo-activation was performed by a) continuous light (500 mW/cm2) for 40 seconds; b) stepped light with low intensity (150 mW/cm2) for 10 seconds and high intensity (500 mW/cm2) for 30 seconds and c) intermittent light (450 mW/cm2) for 60 seconds. The top and bottom surfaces were then polished and after 24 ± 1 hours, the contraction gap was measured by SEM at variable pressure (LEO 435 VP, Cambridge, England). Results were analyzed by ANOVA and the means compared by Tukey's test (5%). The results demonstrated 1) the continuous light method presented the greatest gap values (15.88 µm), while the other methods demonstrated lower polymerization shrinkage values (stepped light, 13.26 µm; intermittent light, 12.79 µm); 2) restorative composites shrunk more at the bottom surface (15.84 µm) than at the top surface (12.11 µm) and (3) the composites Alert (12.02 µm), Surefil (11.86 µm), Z250 (10.81 µm) and P60 (10.17 µm) presented the least contraction gaps, followed by Z100 (15.84 µm) and Definite (14.06 µm) and finally Flow-it (23.09 µm) low viscosity composite, which had the greatest mean value.

SUMMARY:
This study evaluated the tensile bond strength of "repaired" amalgams and compared the degree of microleakage. Amalgam (Cavex avalloy) was condensed into plastic tubes (3 mm in diameter, 10 mm in height) to the half-length. After storage in water at 37°C for two days, the remaining parts of tubes were filled with amalgam (A), cavity varnish (CV)+A, Liner Bond 2V (LB2V)+A, 3M Opal Luting Cement (3MOLC)+A, Panavia F(PF)+A, Metabond(MB)+A, Fuji BondLC(FB)+A, HytacOSB(HOSB)+Hytac Aplitip (H), Liner Bond2V+Clearfil AP-X(CAP). The bond strengths for 15 samples of each restoration group were determined. For the microleakage study, MOD cavities of 90 extracted human premolars were used. The distal half of cavities were filled with amalgam. After storage in water at 37¡C for two days, the mesial half of the cavities were filled to simulate a clinical repair. The "repair" was placed using the procedures applied in the bond strength study. The teeth were stained with basic fuchsine (0.5%), sectioned and evaluated for dye penetration. In both parts of study, the data were analyzed by ANOVA and Duncan's multiple range tests. Bond strength values (MPa) were: A+PF+A 3.84±1.08, A+LB2V+A 3.15±0.97, A+LB2V+CAP 3.05±0.53, A+MB+A 2.86±0.88, A+HOSB+H 2.58±0.51, A+3MOLC+A 2.11±0.75, A+FB+A 0.68±0.59. The repaired A+A and A+CV+A groups were separated before testing. The A+PF+A group showed the highest bond strength (p<0.05). Microleakage in the cervical margins of repaired restorations was lower in the amalgam groups than microleakage in the resin composite and compomer groups. PF, MB, 3MOLC and FB performed better at the amalgam "repair" interface. The A+LB2V+A group showed no microleakage at both the occlusal and gingival test regions.

PURPOSE:
Treatment of a caries active patient requires the clinician to be knowledgeable in the restorative and risk management issues with which these patients often present. Modifications of risk factors that promote dental caries play an important part in the long-term restorative success in these patients. Patient compliance to recommendations addressing modifiable caries risk factors for maintenance of oral health is important to long-term caries risk management. Effective dentist-patient or hygienist-patient communication is a first step to encouraging a proactive role by the patient. Others have reported verbal communication accompanied by written communication to result in better compliance compared to verbal communication, alone (Tagliacozzo & Ima, 1970; MacDonald, MacDonald & Phoenix, 1977; Baker & others, 1991; Harvey & Plumridge, 1991; Vukmir & others, 1993; Makoul, Arntson & Schofield, 1995). Further evidence shows that medical patients who misunderstand their treatment plans and associated instructions usually exhibit poor compliance to following directions (Cargil, 1992; Counsell, Geddis & Smith, 1993; Vukmir & others, 1993; Makoul & others, 1995; Mayeaux & others, 1996). Computer-generated (printed) instructions were shown to significantly increase compliance to emergency room instructions when compared to verbal or verbal + hand-written instructions (Vukmir & others, 1993). Written instructions for use in management of dental caries have not been widely addressed in the literature (Fuller & Harding, 1991; Benn & others, 1997). This report presents a novel computer-generated, graphic approach to written communication that recognizes the patient's need to be reminded that home care consists of daily cyclic events. The objective of this approach is to promote communication with and comprehension by a wider population range than what might be affected by text-only instructions. The software for this method is pre-loaded with recommendations that can be modified by the dentist or hygienist and can be easily adapted as part of a comprehensive disease management program used in the office.

SUMMARY:
A fundamental issue of restorative treatment is assessing the different conditions of cases not only from tooth-to-tooth but also from the activity of each caries lesion and the size of the cavity. In addition, restorative treatment is sometimes carried out for prosthetic and cosmetic purposes and involves cutting sound, unaffected dentin. These aspects are outlined in classic textbooks and are based on the principles described by Black (1908). However, each factor and its relative importance has changed over the years. Significant time has been devoted to improving the important technical aspects of performing restorative treatment. Traditionally, these aspects have primarily been related to cavity design, choice of restorative material and the clinical procedures involved. In this context, Dr Michael Buonocore's contributions must be recognized because the adhesive technique he introduced has become an integral part of modern operative dentistry.

Operative dentistry today also focuses on cavity design and selecting restorative materials.

Less effort has been placed on incorporating what is known about the pattern of caries progression and how it relates to caries removal or excavation. Although the reaction pattern of the pulp-dentin organ is quite different in terms of the nature of active (rapid-progressing) and arrested (slow-progressing) lesions, no widespread major distinction has been made regarding the different restorative treatment approaches in these situations.

This presentation updates the progression and clinical management of dentin caries and how it relates to treating deep caries lesions.

SUMMARY:
This study evaluated the clinical performance of a self-etching adhesive for resin composites over one year. Thirty pairs of restorations of Pertac II, using the adhesive Prompt L-Pop, were placed in caries-free cervical erosion/abfraction lesions without tooth preparation. One of each pair was cured using "soft-start" polymerization, while the other was polymerized with high-intensity halogen light. Restorations were clinically evaluated at baseline, six and 12 months using modified Ryge/USPHS criteria. Although no significant difference (p>0.05) was observed between the curing methods, adhesive performance was poor, with a 35% loss of restorations overall.

SUMMARY:
This study evaluated the three-year clinical performance of a polyacid-modified resin composite material, Dyract (DeTrey/Dentsply, Konstanz, Germany), in Class III cavities.

Sixty-two Class III cavities in 30 patients were restored with Dyract. Restorations were clinically evaluated at baseline, one-, two- and three-year recalls according to the modified Ryge criteria by two experienced, calibrated examiners.

After three years, the retention rate was 96.7%. At the one-year interval, one restoration had to be replaced due to sensitivity. At the two-year recall, one restoration, with a caries lesion adjacent to its margin, was clinically unacceptable and had to be replaced. Except for these two restorations, all other restorations were clinically acceptable in regard to color match, marginal discoloration, wear or loss of anatomical form, caries, marginal adaptation and surface texture after three years. At the end of three years, marginal discoloration was statistically significant (p=0.017) but did not require replacement of any of the restorations.

Dyract exhibited significant marginal discoloration after three-year clinical performance in Class III cavities.

SUMMARY:
This study compared a visual ranked scoring system and a radiographic ranked scoring system for occlusal caries detection with the level of infection of dentin. Seventy-five third-molars, designated for extraction, were professionally cleaned. Caries was scored according to a visual ranked scoring system at a selected site in the groove-fossa system. Radiographs of the teeth were available and caries was recorded along a five-point ranked scoring system. Each tooth was extracted and hemi-sectioned through the investigation site under aseptic conditions. A burful of dentin was removed from the EDJ of one of the section faces and these samples were processed to establish the level of dentin infection. The depth of the lesion was assessed on the other section face using a five-point ranked histological scoring system. A strong relationship was observed between the histological lesion depth and visual score (rs=0.93) while a moderate relationship was seen between lesion depth and radiographic scores (rs=0.77). The dentin from teeth with cavities exposing dentin was heavily infected. The dentin from teeth with microcavities or grey discoloration of the dentin was less infected than the lesions with frank cavitation (score 4) (p<0.05, t-test), but more infected than the initial lesions (p<0.05, t-test). The latter lesions showed minimal infection. A similar tendency was seen with respect to increasing radiographic scores and the level of infection of the dentin.

SUMMARY:
This study examined the effect of caries disclosing dyes on composite to dentin shear bond strengths of a total etch, one-bottle and two self-etching, non-rinsing primer dental adhesives. Two caries disclosing dyes were evaluated, Seek and Snoop, with three dentin adhesives, Prime & Bond NT, Prompt L-Pop and Clearfil SE Bond. Extracted human molars stored in 0.2% sodium azide were sectioned longitudinally to expose dentin and embedded in acrylic, leaving the dentin exposed. Each dentin adhesive had three test groups (n=12); a control and one with each of the caries disclosing dyes. The control group had the dentin conditioned and the adhesive applied following the manufacturer's instructions. The caries disclosing dye groups had the dentin first treated for 10 seconds with the disclosing dye, rinsed, then the dentin adhesives were applied as in the controls. A column of Tetric Ceram was bonded after dentin adhesive placement to each specimen and light cured. Specimens were stored in room temperature water for 24 hours, thermocycled for 1,000 cycles between 5¡C and 55¡C and tested in shear until failure. Mean ± SD shear bond values (SBV) were determined in MPa. A one-way ANOVA and Student Neuman Keuls multiple comparison test within each DBS were performed at a significance level of p<0.05 to analyze the caries disclosing dyes input on SBV versus the controls. Surface analysis to determine the nature of the type of dentin/composite fracture/ separation was also performed. For the fracture analysis data, a Chi-Square test was performed at a significance level of p<0.05. The results of this study indicate that using the two tested caries disclosing dyes, with a total etch, one bottle and two self-etching, non-rinsing primer dental adhesives did not negatively affect the dentin-to-composite shear bond strengths of the three tested dentin bonding systems (p>0.05).

SUMMARY:
Packable composite restorations have become a popular alternative to dental amalgam restorations in posterior teeth. A drawback inherent to composites is their difficulty in polishing, which often results in a dull or rough surface. This study compared the surface roughness of a resin-based hybrid composite material and five packable resin-based composites polished with either aluminum oxide disks or a rubber polishing system. Sixteen specimens of each of the six composite materials were polished with either Sof-Lex XT disks or Enhance rubber polishers followed by fine and superfine polishing pastes. The specimens were evaluated for surface roughness using surface profilometry. Mean values were calculated for each material type and method of polishing. Data were subjected to a two-way ANOVA. Post hoc comparison was accomplished using Tukey's HSD. No significant difference in surface roughness was detected among polishing techniques (p=0.067); however, a strong trend-that aluminum oxide disks provided a smoother surface than rubber polishers in five out of six materials-was noted.

SUMMARY:
Flowable resin composites have been recommended for many clinical uses and have been formulated in a variety of compositions and viscosities to meet various uses. This study compared the variation in viscosity of flowable resin composites using the ADA Flow Test and measured film thickness with a test to simulate flow during cementation. The film thickness test for the flowable resin composites was performed at three different seating pressures to simulate pressure variation during seating of porcelain veneers, one of the potential uses of flowable resin composites that may favor a lower viscosity. The following flowable resin composites were eval-uated: Revolution, StarFlow, Aeliteflo LV, Aelite, Flow-It, FloRestore, Versaflo, Durafill Flow and Tetric Flow, with Nexus2, a composite luting resin used as a control.

Flow characteristic measurements suggest that resin composites may be divided into high flow (StarFlow, Revolution, Aeliteflo LV), medium flow (FloRestore, Durafill Flow, Flow-It) and low flow (Tetric Flow, Versaflo, Nexus2, Aelite) groupings. The film thickness measurements agreed with the ADA flow test, except for two exceptions. Durafill Flow resin composite had a higher film thickness than expected based on the ADA flow test. Also, Aeliteflo unexpectedly had a lower film thickness.

At the lowest seating pressure (.016MPa) tested, eight out of the nine resin composites tested as well as the control luting resin had a film thickness greater than the 25 microns used as the clinical standard for cement film thickness. However, at the highest seating pressure (.038MPa) tested, only two and the control, Versaflo, Durafill Flow and Nexus2, had film thicknesses significantly greater than 25 microns. The highly filled Nexus2 luting resin had the highest film thickness at all seating pressures.

SUMMARY:
Endodontic therapy is accessed occlusally in posterior teeth, many of which have large, pre-existing amalgam restorations. These teeth are also commonly restored with an occlusal amalgam to repair the access opening. This study determined the fracture resistance of complex amalgam restorations that have repaired endodontic access compared with original, unrepaired, complex amalgams on endodontically-treated teeth. Two groups of 30 molars were used in the study. The first group was decoronated and received an endodontic access preparation. These teeth were restored using chamber retention and four TMS pins. The second group was decoronated and restored using pin retention. Later, they received an endodontic access through the restoration. The access was then repaired with amalgam. The samples were loaded in an Instron Universal Testing Machine until failure. The Group 1 samples failed at a mean force of 2297.5 N. The mean failure load for the samples in Group 2 was 1586.1 N. Student's t-test found this difference to be statistically significant. Endodontic access through an amalgam crown significantly compromises the fracture strength of the original restoration.

SUMMARY:
The short-term fluoride release of a giomer (Reactmer), a compomer (Dyract AP), a conventional glass ionomer cement (Fuji II Cap) and a resin-modified glass ionomer cement (Fuji II LC) was evaluated and compared. Specimen discs (6 ± 0.2 mm diameter and 1 ± 0.2 mm thick) were prepared for each material using custom molds. Each disc was placed in 1 ml of deionized for 24 hours at 37¼C. After one day, the water was extracted and analyzed. The specimen discs were then re-immersed into another 1 ml of fresh deionized water. The procedure of removing and refilling the water was repeated for 28 days. Sample solutions taken during the first seven days and at days 14, 21 and 28 were introduced into a capillary electrophoresis system using field amplified sample injection (FASI) to determine fluoride release. Data was analyzed using factorial ANOVA/Scheffe's post-hoc test at significance level 0.05. An initial fluoride "burst" effect was observed with glass ionomers. Both compomer and giomer did not show an initial fluoride "burst" effect. With the exception of the compomer, fluoride release at day one was generally significantly greater than at the other time intervals. The glass ionomers released significantly more fluoride than the compomer and giomer at day one. Although fluoride release of the giomer was significantly greater than the other materials at day seven, it became significantly lower at day 28.

SUMMARY:
This study evaluated the effect of four different packing times on the Knoop Hardness Number of three composites (Surefil, Z100 and Spectrum TPH). Ten samples of each composite were prepared for each packing time and 10 readings were made on each sample to produce the KHN.

Photomicrographs were made of 147 indentations to determine whether the indentations had routinely been made on porosity-free sites.

Statistical analysis was made using two-way ANOVA and least square means. Generally, as the packing time increased, the KHN decreased, and although the indentations appeared to have been made in porosity-free composite, the potential effect of porosities was not discounted. Increasing the packing time for clinical composites may result in a lower KHN and increased clinical wear, which would further increase if also associated with porosities within the composite.

SUMMARY:
Pulp tissue reactions to a fluoride-releasing all-in-one resin bonding system (Reactmer Bond and Reactmer Paste) in non-exposed monkey teeth were histopathologically evaluated at three, 30, and 90 days after restoration. No serious inflammatory reactions of the pulp, such as necrosis or abscess formation, were observed. At 90 days in the Reactmer group, odontoblastic change and inflammatory cell infiltration were not observed, and slight irritation dentin formation was formed. The pulpal response of the Reactmer group was minimally different from that of the control group. Consequently, the Reactmer system was determined as being biologically compatible with vital pulps.

SUMMARY:
This study examined the relationship between the bond agent application duration and the dentin bond strength of several single-application bonding systems. The restorative material/bonding systems used were Reactmer, with its single-application bonding system Reactmer Bond (RB, Shofu Inc, Kyoto, Japan); Palfique Estelite, with its single-application bonding system One-Up Bond F (OU, Tokuyama Co, Tokyo, Japan) and F2000 Compomer, with its bonding system Primer/Adhesive in Clicker (F2, 3M Dental Products, St Paul, MN 55144, USA). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600 SiC to expose labial dentin. Adhesives were applied for 5, 10, 20, 30 and 60 seconds, and restorative materials were condensed into a Teflon mold (¯4 x 2 mm) on the dentin and light activated. Fifteen samples per test group were stored in 37¡C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/min. One-way ANOVA followed by Duncan test (p=0.05) was done. SEM observations of the treated dentin surface were also conducted. The dentin bond strength ranged from 6.9 ± 2.4 to 11.2 ± 2.8 MPa for RB, 8.9 ± 2.2 to 12.2 ± 1.9 MPa for OU, and 7.8 ± 3.1 to 11.4 ± 2.6 MPa for F2. No significant differences were found among the 10-60 second application duration groups for the systems used. From the SEM observations, demineralization of the dentin surface was more pronounced with longer application duration. The data suggest that the duration of single-application bonding systems was not a crucial factor for determining dentin bond strength, even though morphological changes were observed on the dentin surface.

SUMMARY:
Standardized Class IV cavity preparations were made in 48 human incisors. They were then divided into three groups of 16 teeth each. Group 1 was prepared with no internal retentive features. Groups 2 and 3 included an internal pin channel prepared with a #330 and a #329 bur, respectively. All specimens were restored with a micro-hybrid resin-based composite restorative material and a fifth generation dentin bonding system. Specimens were loaded to failure in an Instron Universal Testing Machine perpendicular to the long axis of the teeth. There was no evidence to suggest a difference in force required to dislodge the restoration among the three groups tested (p=0.185). Resin composite pins do not increase the retention of Class IV resin composite restorations.

SUMMARY:
This study tested the hypothesis that long-term durability of resin bonds to dentin is directly related to the nanoleakage of dentin bonding systems. Extracted human third molars were ground flat with 600-grit SiC paper under running water to expose middle dentin. Clearfil Liner Bond 2V (LB2V) or Fluoro Bond (FB) was applied to dentin surfaces according to the manufacturer's instructions. A crown was built-up with Clearfil AP-X resin composite, and the specimens were stored in water for 24 hours at 37¡C. The bonded assemblies were vertically sectioned into approximately 0.7 mm thick slabs and trimmed for microtensile bond test. All slabs were immersed in individual bottles of water at 37¡C, which was changed every day. Specimens were incubated for one day, and three, six, and nine months, and at the specified time period, they were randomly divided to two subgroups: 50% AgNO3 and the control. In the 50% AgNO3 subgroup, the slabs were immersed for one hour in 50% AgNO3, followed by exposure in a photo-developing solution for 12 hours just prior to debonding. The specimens in the control subgroup were soaked in water until debonding. Then, all specimens were subjected to microtensile bond testing. The debonded specimens of the AgNO3 subgroup had micrographs subjected to image analysis by NIH Image PC (Scion, Fredrick, MD, USA), and the area of silver penetration was quantitated. The bond strength data and silver penetration areas were subjected to two- and three-way ANOVA and Fisher's PLSD test at the 95% level of confidence. Regression analysis was used to test the relationship between bond strengths and the silver penetration area at each time period. For both adhesive systems, the bond strengths gradually decreased over time, although there were no statistically significant differences in the FB bond strength among the four time periods tested (p>0.05). Silver penetration in specimens bonded with LB2V and FB gradually increased over time. Regression analysis showed a higher correlation between bond strength and silver penetration at 9 months for specimens bonded with LB2V (R2=0.844) than at shorter time periods. The authors speculate that hydrolytic degradation within the hybrid layer gradually increased due to water penetration through nanoleakage channels, resulting in lower bond strengths and interfacial failure after as little as nine months.

SUMMARY:
Shrinkage in light curing resin composites is assumed to be directed toward the light source. However, the strong bond at the dentin-resin interface achieved by newer generation dentin bonding systems may affect the direction of polymerization shrinkage. In this study, various curing modes of adhesive resin simulating different bond qualities were applied to determine the extent of interfacial gap formation with a scanning electron microscope. We also measured the free surface depression with a profilometer. The direction of polymerization shrinkage was inferred from the ratio of the interfacial gap measurement at the floor to the free surface depression. Various curing modes used in this study include Group 1: light curing of resin composite without the bonding agent as the negative control; Group 2: simultaneous light curing of the bonding agent and resin composite; Group 3: start of the chemical cure of the dual-cured bonding agent before light curing the resin composite; Group 4: curing the light-initiated bonding agent before insertion and light curing of the resin composite. When the bonding agent was light cured prior to inserting the resin composite (Group 4), the free surface depression was the greatest and the interfacial gap smallest among those in all groups. Therefore, if a good bond between dentin and resin composite can be established, the shrinkage flow will be directed toward a center located near the bonded interface rather than toward the incident light, thus reducing detrimental shrinkage stress.

SUMMARY:
This study examined the surface morphological changes of prosthodontic composite materials when exposed to an acidulated phosphate fluoride (APF) agent and the effectiveness of subsequent polishing on APF-treated material surfaces. Nine composite materials (Conquest Sculpture, Dentacolor Sirius, Diamond Crown, Estenia, Eye Sight, Gradia, New Meta Color Infis, Prywood Color and Vita Zeta) were assessed. After half the surface of each composite disk specimen was coated with a varnish, the entire surface was treated with an APF solution (Floden A). The varnish was removed and a surface analyzer helped to determine changes in the surface roughness value (Ra). A scanning electron microscope (SEM) was used to observe relief patterns for all specimens. The composite surfaces treated with the APF were then polished and examined using the SEM. Ra values for the Conquest Sculpture, Diamond Crown, Estenia, Gradia and Prywood Color materials (macro inorganic filler) showed a significant increase as a result of treatment with the APF solution, and the macro-inorganic fillers (Estenia, Prywood Color) demonstrated noticeable etched patterns. There were no significant statistical differences in Ra values between the treated and untreated halves for any of the microfilled materials. In addition, photographs of the microfilled materials indicated no changes in the surfaces and showed the effectiveness of polishing on the material surfaces. Microfilled material surfaces were not sensitive to the APF agent compared with macro-inorganic filled material surfaces. For the latter, the effectiveness of surface polishing was demonstrated.

Dr John W Reinhardt

Dr Nairn H F Wilson

SUMMARY:
This study evaluated the influence of the pulp protection technique on clinical performance of amalgam restorations after three years, with particular reference to post-operative sensitivity and secondary caries. One hundred and twenty (120) Class II amalgam restorations (68 premolars, 52 molars; 78 MOD, 42 OD/MO) were placed in 30 participants (four restorations per participant). The restorations were divided into four groups according to the pulp protection technique used: copal varnish; 2% neutral sodium fluoride; adhesive resin and no pulp protection. The parameters evaluated were post-operative sensitivity, staining of the dental structure, tooth vitality, partial or total loss of the restoration and secondary caries. One hundred and eight (108) restorations were available for evaluation after three years. No partial or total loss of restorations had occurred; all teeth were vital, no tooth structure staining or secondary caries was detected in any of the restored teeth. Post-operative sensitivity was observed only in two restorations at baseline and at seven-days. The three-year clinical performance of teeth restored with a high, copper-dispersed phase amalgam was not affected by the choice of pulp protection technique.

SUMMARY:
This clinical study evaluated the retention rate and caries protection of a medium-filled (46% volume) flowable restorative material (CuRay-Match, OMNII Oral Pharmaceuticals, West Palm Beach, FL 33409, USA) compared to an unfilled sealant (Delton, Dentsply Caulk, Milford, DE 19963, USA). Using a half-mouth design, sealants were applied on randomly assigned caries-free first and/or second permanent molars of 32 children ranging in age from 6-11 years. A total of 118 teeth were etched, dried and sealed. Teeth were evaluated at one, six and 18-month intervals. After one month, 52 teeth sealed with unfilled sealant were intact compared with 46 sealed with a medium-filled resin, and after six months, 36 teeth sealed with an unfilled sealant were intact compared with 27 that were sealed with a medium-filled resin. After 18 months, 29 teeth were still fully sealed with an unfilled sealant, whereas 18 were sealed with a medium-filled resin. The difference between the two groups was not statistically significant. Regarding caries development, four teeth sealed with a medium-filled material and five teeth sealed with an unfilled sealant were decayed after 18 months. These results indicate that a medium-filled flowable restorative material did not perform better in retention rate and caries increment when compared to an unfilled conventional sealant. However, the effect of the additional techniques, such as the use of bonding agent and fissurotomy on retention rates should be evaluated in further studies.

SUMMARY:
This study compared the pulp response to seven adhesive resins (three single-bottle and four self-etching primers) and their companion resin composite systems with a commercial calcium hydroxide material when applied to exposed monkey pulps. The control group was capped with Dycal (DY), while the experimental groups were capped with one of the following adhesive resin systems: AQ Bond (AQ), Single Bond (SB), Imperva Fluorobond (IF), One Step (OS), Prime&Bond NT (PBNT), Perme Bond F (PBF) and One-up Bond F (OBF). Histopathologic evaluation of pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation and bacterial penetration at the 3rd, 30th and 90th post-operative days was done using light microscopy. Data were analyzed using the Kruskal-Wallis test followed by the Least Significant Difference Test to determine differences between the control group and the experimental groups at each observation period. The correlation of inflammatory cell infiltration and bacterial presence was investigated by the Kendall correlation analysis. All tests were performed at a 95% level of confidence. The pulpal responses of groups DY, SB, OS, PBF and OBF were generally characterized by none-to-mild pulp tissue disorganization and inflammatory cell infiltration. Also, initiation of reparative dentin formation was found earlier in Group DY, resulting in more complete dentin bridges at the 30- and 90-day observation periods. Groups AQ, IF and PBNT had significantly more inflammatory cell infiltration and a lower incidence of reparative dentin formation than Group DY. A significant correlation was detected between inflammatory cell infiltration and the presence of bacteria. It is concluded that the pulp response to SB, OS, PBF and OBF is not significantly different from the calcium hydroxide preparation. However, calcium hydroxide capping resulted in a higher incidence and faster rate of reparative dentin formation.

SUMMARY:
In the direct treatment of cervical lesions and to improve the impression-making procedure prior to fabricating indirect restorations, exposure of the gingival sulcus and control of hemorrhage or gingival fluid seepage are a prerequisite. For gingival displacement, cords impregnated with medicaments are widely used. In this investigation, the authors first studied in vitro the time course of fluid absorption by retraction cords immersed in test solutions. Thereafter, in a clinical trial, they examined the microcirculatory responses of the gingival margin after subgingival insertion and removal of retraction cords pre-soaked in solutions containing saline, AlCl3, Fe2(SO4)3 or epinephrine. Blood flow was recorded using laser Doppler technique. Blood perfusion fell markedly upon inserting the retraction cord, and this response was invariably present with all the compounds tested. After five-minutes, the decrease became less apparent with cords that were impregnated with physiological saline, AlCl3 or Fe2(SO4)3. Removing the cord elicited a prompt, marked and sustained increase in gingival microcirculation. However, removal of the cord impregnated with 0.1% epinephrine failed to reverse the decreased perfusion, and blood flow to the gingival margin remained low over an additional 20-minute observation. The results of this study indicate that with the exception of epinephrine, all retraction substances tested produced gingival hyperemia for operative procedures. Only epinephrine exhibited sustained vasoconstrictor response. It is anticipated that using laser Doppler flowmetry may be a suitable technique to evaluate the appropriate concentration of epinephrine that would elicit topical vasoconstriction.

SUMMARY:
This study evaluated the fracture resistance of maxillary premolars with MOD cavity preparation and simulated periodontal ligament. The teeth were restored with silver amalgam (G1), Scotchbond Multi-Purpose Plus and silver amalgam (G2) and Panavia F and silver amalgam (G3). After restorations were made, the specimens were stored at 37ºC for 24 hours at 100% humidity and submitted to the compression test in the Universal Testing Machine (Instron). The statistical analysis of the results (ANOVA and Tukey Test) revealed that the fracture resistance of group 2 (G2=105.720 kgF) was superior to those of groups 1 (G1=72.433 kgF) and 3 (G3=80.505 kgF) that did not differ between them.

SUMMARY:
This in vitro study evaluated the pH value of active and arrested caries lesions in deep dentinal caries using a pH-imaging microscope (SCHEM-100, HORIBA Ltd, Kyoto, Japan). Buccal-lingual cut sections of extracted human teeth that had either active or arrested dentinal caries lesions were placed on the pH-imaging sensor of the microscope. The pH values were compared statistically by one-way ANOVA and Fisher’s PLSD test (p<0.05). In addition, both types of caries lesions were compared with a caries detector solution for this pH-imaging characterization. For both active and arrested lesions in dentin, the lowest pH values in the caries lesions (range from 5.3 to 6.6) were lower than that of intact dentin (range from 6.8 to 7.4). There were statistical differences between the lowest pH value within the active lesion (range from 5.3 to 5.8) and the arrested lesion (range from 6.3 to 6.6) (p<0.05). Although the arrested lesion was unstainable and impermeable to the dye, there was a close relationship between dye staining and pH-imaging characterization within the active lesion from visual inspection.

SUMMARY:
Scanning electron microscopy (SEM) evaluated the effect of different caries removal techniques on human dentin topography. Thirty-six extracted human carious mandibular molars were randomly assigned to six groups according to caries removal technique. Carious tissue was removed by hand excavation, bur excavation, air-abrasion, laser ablation, chemomechanical methods and sono-abrasion. The remaining dentin surfaces were replicated and gold-coated. The surfaces were examined using SEM and distinct differences in appearance were observed among specimens treated with different caries removal techniques. While hand-excavated, bur-excavated and air-abraded carious dentin surfaces were covered with a residual smear layer, sono-abrasion with patent dentinal tubules completely removed the smear layer. A few patent orifices of dentinal tubules were observed in dentin subjected to laser ablation and chemo-mechanical caries removal.

SUMMARY:
Despite great progress in the production of new dental polymers, application of these products is still controversial. The unlined utilization of cytotoxic adhesive materials on pulpal dentin can adversely influence the pulp, leading to alterations in local microcirculation that can be an early sign of pathological changes. In a previous study by the authors, the effect of an acetone-free bondmaterial was examined on the vascular diameter of pulpal vessels by means of vitalmicroscopy. In this study, experiments comparing experimental data provided by an acetone-containing bondmaterial to these earlier findings with acetone-free ones have been performed. Thirty male Sprague-Dawley rats (weighing 333±9 g) were used for this investigation. The first lower incisor was prepared for vitalmicroscopy. Changes in vessel diameter were recorded prior to and 5, 15, 30 and 60 minutes after the investigated materials (Scotchbond Multi-Purpose Dental Adhesive System or Prime & Bond 2.1) were administered on dentin as recommended by the manufacturer. In control rats (saline administration), the vessel diameter was stable during the experiment. In the presence of acetone-free bondmaterial (Scotchbond), the vessel diameter was increased during the experimental period in relation to the baseline (12.15±2.85%; 16.36±2.39%; 14.16±3.48%; 12.12±3.72%). In the presence of acetone-containing bondmaterial (Prime & Bond 2.1), a similar result was observed (10.56±2.27%; 16.13±2.94%; 17.88±2.54%; 14.54±3.16%). The differences between the control values and those registered with test groups were significant (p<0.05; ANOVA). There was no significant difference among the test groups. The results of this study suggest that dental bond materials applied on a very thin layer of dentin may affect the blood supply to the dental pulp. However, no stasis or prestasis has been detected, indicating a possible reversible effect. The authors could not show any statistical difference between the vasodilatation caused by the acetone-containing and the acetone-free bond material.

SUMMARY:
Despite limited scientific evaluation, there is an increased use of low elastic modulus flowable resin composite (FRC) as a stress-relieving gingival increment in Class II restorations. This study compared marginal leakage in preparations with gingival margins in enamel or dentin/cementum (sub-CEJ and supra-CEJ) after FRC was used as a gingival increment to hybrid resin composite used alone. In addition, the extent of leakage around restorations with or without the use of FRC gingival increments when light curing the resin composites from occlusal direction only or buccal, lingual and occlusal directions was compared. Sixty extracted human molars were prepared with two identical Class II (MO and OD) preparations (30 were 1 mm sub-CEJ and 30 were 1 mm supra-CEJ) and randomly assigned to six groups. After etching, dentin-bonding agent was applied to all prepared tooth surfaces according to the manufacturer’s specifications. One of three different thicknesses of FRC (0.5 mm, 1 mm or 2 mm) was placed on the gingival floor, cured and a hybrid resin composite was placed occlusally to complete the restoration. The control preparation on each tooth was restored in the same manner, except that a hybrid resin composite was used for both the gingival and occlusal increments. The restored teeth were thermocycled (300 cycles), then immersed in 50% silver nitrate prior to the hemi-section and measured for leakage under a light microscope. The data were evaluated using paired measures analysis of variance (ANOVA). Most of the occlusal margins showed no leakage, while almost every gingival margin demonstrated some silver nitrate penetration regardless of whether it was located sub or supra-CEJ, although significantly less leakage was found in restorations with supra-CEJ margins (p=0.0001). Among supra-CEJ restorations, there was a pronounced reduction in leakage as FRC thickness increased (p=0.0005). In the teeth restored with the gingival-margin located supra-CEJ, the 2 mm thickness FRC gingival increment showed significantly less leakage (p<0.01) compared with the 0.5 mm thickness of FRC gingival increment. The direction of the curing light did not affect the extent of leakage (p>0.05). The use of FRC material as a gingival increment sub-CEJ in posterior hybrid resin restorations produced no significant difference in leakage (p>0.05). The results of this study indicated that restorations located supra-CEJ (with gingival margins in enamel) with 2 mm thick FRC gingival increments demonstrated significantly less leakage than did those with 0.5 mm FRC. When the margin of the restoration was located sub-CEJ (in dentin/cementum), neither the thickness nor the presence of FRC as a gingival increment significantly influenced the marginal leakage.

SUMMARY:
This study investigated the surface texture of two resin-modified glass ionomer cements (RMGICs) in the vertical and horizontal axis after treatment with different finishing/polishing systems. Class V preparations were made on the buccal and lingual/palatal surfaces of freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (GC) and Photac-Fil Quick (ESPE) according to manufacturers’ instructions. Immediately after light-polymerization, gross finishing was done with 8-flute tungsten carbide burs. The teeth were then randomly divided into four groups and finished/polished with (a) Robot Carbides (RC); (b) Super-Snap system (SS); (c) OneGloss (OG) and (d) CompoSite Points (CS). The sample size for each material-finishing/polishing system combination was eight. The mean surface roughness (µm) in vertical (RaV) and horizontal (RaH) axis was measured using a profilometer. Data was subjected to ANOVA/Scheffe’s tests and Independent Samples t-test at significance level 0.05. Mean RaV ranged from 0.59-1.31 and 0.83-1.52, while mean RaH ranged from 0.80-1.43 and 0.85-1.58 for Fuji II LC and Photac-Fil, respectively. Results of statistical analysis were as follows: Fuji II LC: RaV-RC, SS

SUMMARY:
The hybrid layer created in caries-affected dentin has not been fully elucidated and may influence bond durability. This study investigated the nanoleakage patterns of caries-affected dentin after excavation with Carisolv or conventional instruments treated with one of three adhesive systems. Flat occlusal dentin surfaces, including carious lesions, were prepared from extracted human molars and finished with wet 600-grit silicon carbide paper. Carious dentin was removed with Carisolv or round steel burs in conjunction with Caries Detector. PermaQuik, Single Bond or One-Up Bond F was bonded to the excavated dentin surfaces and adjacent flat occlusal surfaces and it was covered with Silux Plus resin-based composite. After 24-hour storage in 37°C water, the bonded interfaces were polished to remove flash, and the surrounding tooth surfaces were coated with nail varnish. Specimens were immersed in 50% (w/v) silver nitrate solution for 24 hours, exposed to photo developing solution for eight hours, then sectioned longitudinally through the bonded, excavated dentin or “normal” dentin surfaces. The sectioned surfaces were polished, carbon coated and observed in a Field Emission-SEM using back-scattered electrons. Silver deposition occurred along the base of the hybrid layer for all specimens. However, Single Bond showed a greater density of silver deposition in the caries-affected dentin compared with normal dentin. PermaQuik had a thicker hybrid layer in caries-affected dentin than normal dentin. One-Up Bond F exhibited a thin hybrid layer in normal dentin, but the hybrid layer was often difficult to detect in caries-affected dentin.

SUMMARY:
This in vitro study evaluated the effect of rebonding on microleakage of a resin composite, a condensable resin and two polyacid-modified resin composite restorations. Standardized cylindrical Class V dentin cavities were prepared on the buccal root surfaces of 240 extracted bovine incisive teeth. The prepared teeth were randomly assigned to four groups of 60 teeth and restored with the following restorative systems: I—(ZS) Z100/Scotchbond Multi-Purpose Plus; II—(SS) Solitaire/Solid Bond; III—(FS) Freedom/Stae; IV—(FSB) F200/Single Bond. Thirty teeth of each group were rebonded with a low-viscosity resin (Fortify/BISCO), according to the manufacturer’s instructions. The remaining teeth received no treatment. All teeth were thermocycled for 5,000 cycles and brushed by hand three times a day for 10 days using a toothbrush and a slurry of dentifrice and water. Specimens were stained in a 2% methylene blue solution and longitudinally sectioned with diamond disks. Microleakage was scored on a scale of 0 to 3. The Kruskal-Wallis test showed statistically significant differences among the groups (h=156.54; a<0.05). Pairwise comparison by means of the least significant difference showed that (SS) and (FS) with or without rebonding were not statistically different from each other. These groups showed the highest microleakage differences from (ZS) and (FSB) with or without rebonding. (ZS) with rebonding showed the lowest microleakage that was not statistically different from (ZS) without rebonding and (FSB) with rebonding.

SUMMARY:
The bonding performance of current adhesive systems to primary enamel has not been thoroughly researched. This study compared the micro-shear bond strength of two adhesive systems to primary and permanent tooth enamel. Two commercially available resin adhesives, a self-etching primer system (Clearfil SE Bond) and a single-bottle adhesive system (Single Bond) used with a total-etch wet bonding technique were tested. A micro-shear bond test was used to examine the adhesive systems on mid-coronal buccal enamel of extracted primary or permanent teeth. In addition, etched enamel surfaces and etched-bonded enamel interfaces were examined using scanning electron microscopy (SEM). No statistically significant differences of shear bond strength values were found between the primary and permanent enamel or the adhesive systems used (p>0.01). The SEM observations showed that both adhesive systems etched the primary enamel deeper than the permanent enamel, suggesting that the action of acid etch seemed to be more intense on primary enamel than on permanent enamel. Bonding of the adhesive systems to primary enamel was almost identical to permanent enamel.

SUMMARY:
This in vitro study evaluated the wear resistance of resin composite polymerized using four different light-curing systems. For this, a well-defined cylindrical cavity preparation (4.0 mm in diameter x 3.0 mm in depth) was made in a ceramic block (n=4 per material/light condition). Uncured material, either a universal hybrid composite (Herculite XRV) or a flowable hybrid composite (Revolution Formula 2), was packed and light-cured from the top surface only with one of the four light-curing units: 1) a conventional quartz-tungsten-halogen light, 2) a soft-start light, 3) an argon-ion laser or 4) a plasma-arc curing light. After storing the specimens in deionized water at 37°C for 24 hours, the excess cured material was ground through successive grits up to a final 1200-grit SiC abrasive. The specimens were placed in deionized water at 37°C for an additional 24 hours. Wear simulation was performed using a four-station Leinfelder-type three-body wear device. A slurry of water and unplasticized polymethylmethacrylate beads, simulating an artificial food bolus, was placed on the surface of each resin-composite-restored ceramic block. The entire cycling procedure was carried out 400,000 times. Impressions of each resin composite surface were taken with polyvinylsiloxane and epoxy replicas were made. Wear analyses were conducted by generating tracings across the worn surface of epoxy replicas using profilometer scans. For the universal hybrid composite and the flowable hybrid composite, the lowest wear occurred in specimens that were cured using the conventional quartz-tungsten-halogen light, and the highest wear was detected on those specimens made using the argon-ion laser. For both resin composites, the mean wear for specimens cured using the argon-ion laser was significantly higher than that of the specimens cured with the three other lights, which were statistically similar.

SUMMARY:
This study evalu