A randomized five-year clinical study of a two-step self-etch adhesive with or without selective enamel etching.

The purpose of this study was to evaluate the five-year clinical performance of a two-step self-etch adhesive in non-carious cervical sclerotic lesions with or without selective acid-etching of enamel margins. A total of 104 cervical restorations in 22 patients (46-64 years) were bonded following either self-etch approach (AdheSE non-etch) or a similar application, including selective acid-etching of enamel margins (AdheSE etch), and were restored with resin composite. The restorations were evaluated at baseline and after one, two, three and five-years (84 restorations in 19 patients) according to the USPHS criteria. Data were analyzed using McNemar's test. Cumulative retention rates for the non-etch and etch groups were 82.6% and 86.1% respectively. No significant differences were detected in the retention rates, marginal adaptations at dentin side and secondary caries between the groups. After five-years, the clinical performance of the two-step self-etch adhesive with or without selective acid-etching of enamel margins, was acceptable.

The effect of prophylactic polishing pastes on surface roughness of indirect restorative materials.

The purpose of this study was to evaluate the influence of prophylactic polishing pastes (PPP; Detartrine (DT), Topex (TP)) on surface roughness (R(a)) of indirect composites (IRC; Tescera (TES), Gradia (GRD), and Estenia C&B (EST)), a glass ceramic (Empress 2 layering (E2)), and a leucite reinforced glass ceramic (Empress Esthetic (EE)) with two different (glazed (G); polished (P)) surface preparations. A total of 90 IRC and 120 ceramic discs, 8 mm in diameter and 2 mm thick, were prepared. E2 and EE specimens were randomly divided into two groups (n = 30). One group was glazed (GE2; GEE), while the other group was polished (PE2; PEE) the same as the IRCs. The specimens in each group were subsequently divided into three subgroups: control (C), DT, and TP. R(a) (µm) was evaluated with a profilometer. Data were analyzed by Kruskal Wallis, followed by the Dunn's multiple comparison tests (P < 0.05). DT and TP resulted in significant surface roughening for TES, GRD, and EST, while no significant differences were detected between DT and TP (P > 0.05). PE2 and PEE were not affected by DT or TP (P > 0.05), while GE2 and GEE exhibited significant roughening after TP (P < 0.05). Surface roughness of IRCs and glazed ceramics can be affected by PPP applications.

Three-year clinical evaluation of a two-step self-etch adhesive with or without selective enamel etching in non-carious cervical sclerotic lesions.

OBJECTIVE: The purpose of this prospective, controlled, randomized study was to evaluate the 3-year clinical performance of a two-step self-etch adhesive (AdheSE, Ivoclar Vivadent; Schaan, Liechtenstein) in non-carious cervical sclerotic lesions with or without selective acid-etching of the enamel margins. MATERIAL AND METHODS: Twenty-two patients (mean age 51.5) having at least two pairs of non-carious cervical sclerotic erosion/attrition/abfraction lesions with incisal or occlusal margins in the enamel and gingival margins in the dentin were included in the study. The two-step self-etch adhesive was applied following either the self-etch approach (AdheSE non-etch, n = 52) or a similar application approach, including prior selective acid-etching of the enamel margins (AdheSE etch, n = 52). Composite resin Point 4 (Kerr Corp; Orange, CA, USA) was used as the restorative material for all 104 restorations. The restorations were evaluated at baseline and after 1, 2, and 3 years, according to the modified USPHS criteria. Data were analyzed using McNemar's test (p < 0.05). RESULTS: The retention rates for AdheSE non-etch were 100 %, 98 %, and 91.5 %; whereas, 100 %, 100 %, and 97.9 % retention rates were recorded for AdheSE etch after 1, 2, and 3 years, respectively. No significant differences were detected between the retention rates, marginal adaptation at the dentin side, secondary caries, and postoperative sensitivity (p > 0.05). A significantly higher number of restorations in AdheSE non-etch group showed clinically acceptable slight marginal discoloration (p = 0.0001) and clinically acceptable small marginal defects at the enamel side (p = 0.008) than in the AdheSE etch group. CONCLUSIONS: After 3 years, the two-step self-etch adhesive exhibited acceptable clinical performance with or without selective enamel etching in non-carious cervical sclerotic lesions. CLINICAL RELEVANCE: Selective acid-etching of the enamel margins enhanced the performance of the two-step self-etch adhesive in terms of marginal discoloration and marginal adaptation at the enamel side.

Influence of a prophylaxis paste on surface roughness of different composites, porcelain, enamel and dentin surfaces.

OBJECTIVE: To investigate the effect of a prophylaxis paste on surface roughness of different composites, enamel, dentin and porcelain surfaces. METHODS: Three different composites (FiltekZ250/Group1, Filtek Supreme XT/Group2, Premise/Group3), enamel/Group4, dentin/Group5 and porcelain/Group6 samples were used in this study. All specimens were prepared flat by SiC discs and polished with a diamond polishing paste. The surface roughness measurements were determined with a profilometer after polishing (initial surface roughness). Prophylaxis paste was applied to the samples for 12 seconds, renewing every 6 seconds. After cleaning the samples, roughness values were measured again. Data were analyzed by Kruskal Wallis and Dunn's multiple comparison test. Wilcoxon test was performed for the comparison of the initial and final surface roughness values (P<.05). The results were evaluated within the P<.05 confidence level. RESULTS: The initial and final surface roughness values (µm) were determined as follows: Group1: 0.039±0.009 and 0.157±0.018, Group2: 0.023±0.005 and 0.145±0.027, Group3: 0.028±0.008 and 0.109±0.012, Group4: 0.024±0.006 and 0.071±0.015, Group5: 0.030±0.007 and 0.143±0.029, Group6: 0.024±0.006 and 0.064±0.014. Significant difference was determined between the initial and final values for all groups. CONCLUSIONS: Composite and dentin surfaces were more affected by the application of prophylaxis paste than enamel and porcelain surfaces. The prophylaxis paste increased the surface roughness of all groups, but did not reach the bacterial retention roughness rate of 0.2µm.

Effect of bleaching on microhardness of esthetic restorative materials.

This study evaluated the effect of a high-concentration carbamide peroxide­containing home bleaching system (Opalescence PF) and a hydrogen peroxide­containing over-the-counter bleaching system (Treswhite Supreme) on the microhardness of two nanocomposites (Filtek Supreme XT and Premise) and leucite-reinforced glass ceramic (Empress Esthetic), glass ceramic (Empress 2 layering), and feldspathic porcelain (Matchmaker MC). A total of 100 specimens, 20 of each kind of the restorative materials, 2 mm in thickness and 10 mm in diameter, were fabricated. Then the specimens were polished with SiC paper and 1 µm alumina polishing paste. After polishing, porcelain specimens were glazed in accordance with the manufacturer's instructions. Each type of restorative material was then randomly divided into two groups (n=10), and the specimens were treated with either Opalescence PF or Treswhite Supreme. The microhardness of the specimens before bleaching (baseline) and after bleaching was determined using a digital microhardness tester. Data were analyzed using the Mann-Whitney U-test and the Wilcoxon test. Opalescence PF significantly influenced the hardness of all the restorative materials. Statistically significant decreases with respect to before bleaching were found for Premise (p=0.005), Empress Esthetic (p=0.003), Empress 2 layering (p=0.005), and Matchmaker-MC (p=0.003), whereas a statistically significant increase was observed in Filtek Supreme XT (p=0.028). The difference in the microhardness values between before and after bleaching using Treswhite Supreme was statistically significant only for Premise (p=0.022). High-concentration carbamide peroxide­containing home bleaching may affect the microhardness of restorative materials.

Effect of Er:YAG laser irradiations on shear bond strength of three self-adhesive resin cements to dentin.

OBJECTIVE: The purpose of this study was to evaluate the influence of Er:YAG laser irradiation on shear-bond strength of self-adhesive resin cements to dentin. BACKGROUND DATA: Different laser-irradiation settings are used for dentin-surface pretreatment, which may affect the bond strength of resins. METHODS: Fourty-five extracted third molars were selected, sectioned in a mesiodistal direction, and 90 tooth slabs were obtained. The teeth were ground to expose the dentinal hard tissue with 320- and 600-grit silicon carbide disks. The specimens were randomly assigned to nine groups (n = 10). Surfaces for each group were laser irradiated with 30 Hz/70 mJ (2.1 W), 30 Hz/160 mJ (4.8 W), or non-irradiated (control) for each resin cement (SmartCem2, RelyX Unicem, Multilink Automix). All specimens were stored in distilled water at 37°C for 24 h after luting. Shear-bond testing was carried out by using a Universal testing machine with a crosshead speed of 0.5 mm/min. Data were analyzed with one-way ANOVA and post hoc Tukey HSD tests (p < 0.05). RESULTS: The highest bond-strength value was obtained with SmartCem2, which was irradiated with Er:YAG laser (30 Hz/160 mJ). The lowest values were exhibited in the control group of SmartCem2, RelyX Unicem and Multilink Automix, respectively (4.92 ± 1.68, 7.17 ± 2.88, and 7.93 ± 3.05). CONCLUSION: The 2.1-W and 4.8-W laser ablation did not show any statistically difference for RelyX Unicem and Multilink Automix materials. However, in the SmartCem2 group, laser irradiated with 30 Hz/160 mJ application increased the bond-strength values, and the highest bond-strength results were obtained in this group.

The effect of endodontic irrigants on the microtensile bond strength of dentin adhesives.

INTRODUCTION: The purpose of this study was to evaluate the microtensile bond strength of a total etch (XP-Bond) and a self-etch (Clearfil SE Bond) adhesive system to dentine surfaces treated using endodontic irrigants. METHODS: Twenty-four freshly extracted third molars were used. After creating a smear layer on the coronal midthird portion of the crowns, the teeth were divided into three groups and surfaces were irrigated with distilled water, 5.25% NaOCl + 17% EDTA, and 1.3% NaOCl + BioPure MTAD, respectively. Each group was divided into two subgroups, and a self-etching adhesive and an etch-and-rinse adhesive were applied respectively. The teeth were restored with a composite material and sectioned to produce sticks for microtensile bond testing. RESULTS: The microtensile bond strength of the MTAD + Clearfil SE group was found to be significantly lower than the microtensile bond strength of the distilled water + Clearfil SE Bond group and the NaOCl, EDTA, + Clearfil SE Bond group (p = 0.0001, p = 0.009). CONCLUSIONS: Because of the significant reduction of Clearfil SE Bond to coronal dentine after MTAD application, an etch-and rinse adhesive such as XP-Bond may be preferred if this irrigant has been chosen during endodontic treatment.

A field-trial of two restorative materials used with atraumatic restorative treatment in rural Turkey: 24-month results.

OBJECTIVE: The purpose of this study was to investigate the clinical performance of high-strength glass ionomer cement (HSGIC) and resin-modified glass ionomer (RMGIC) in single and multiple surface carious cavities in the field conditions. MATERIAL AND METHODS: A split-mouth design, including ninety-one fillings placed on contra lateral molar pairs of 37 children, was used in permanent dentition. As filling materials, a HSGIC (Ketac Molar/3M ESPE) and a RMGIC (Vitremer/ 3M ESPE) were used with the Atraumatic Restorative Treatment (ART). Baseline and 6, 12 and 24-month evaluations of the fillings were made with standard-ART and USPHS criteria by two examiners with kappa values of 0.92 and 0.87 for both criteria. RESULTS: According to the USPHS criteria, the retention rates of RMGIC and HSGIC restorations were 100% and 80.9% for single surface, and 100% and 41.2% for multiple surface restorations after 24 months, respectively. Irrespective of surface number, RMGIC was significantly superior to HSGIC (p= 0.004), according to both standard-ART and USPHS criteria. CONCLUSION: The results indicate that RMGIC may be an alternative restorative technique in comparison to high-strength GIC applications in ART-field-trials. However, further clinical and field trials are needed to support this conclusion.

A field-trial of two restorative materials used with atraumatic restorative treatment in rural Turkey: 24-month results

OBJECTIVE: The purpose of this study was to investigate the clinical performance of high-strength glass ionomer cement (HSGIC) and resin-modified glass ionomer (RMGIC) in single and multiple surface carious cavities in the field conditions. MATERIAL AND METHODS: A split-mouth design, including ninety-one fillings placed on contra lateral molar pairs of 37 children, was used in permanent dentition. As filling materials, a HSGIC (Ketac Molar/3M ESPE) and a RMGIC (Vitremer/ 3M ESPE) were used with the Atraumatic Restorative Treatment (ART). Baseline and 6, 12 and 24-month evaluations of the fillings were made with standard-ART and USPHS criteria by two examiners with kappa values of 0.92 and 0.87 for both criteria. RESULTS: According to the USPHS criteria, the retention rates of RMGIC and HSGIC restorations were 100 percent and 80.9 percent for single surface, and 100 percent and 41.2 percent for multiple surface restorations after 24 months, respectively. Irrespective of surface number, RMGIC was significantly superior to HSGIC (p= 0.004), according to both standard-ART and USPHS criteria. CONCLUSION: The results indicate that RMGIC may be an alternative restorative technique in comparison to high-strength GIC applications in ART-field-trials. However, further clinical and field trials are needed to support this conclusion.

Effect of fiber nets, application techniques and flowable composites on microleakage and the effect of fiber nets on polymerization shrinkage in class II MOD cavities.

This study evaluated the effects of fiber nets and application techniques and flowable composites as a liner on microleakage and the effects of fiber nets on polymerization shrinkage in Class II MOD cavities. Standard MOD cavities were performed in 80 extracted third molars. The teeth were randomly divided into eight groups (n=10). Group 1: Filtek Supreme XT (bulk technique) (FSB); Group 2: Filtek Supreme XT (incremental technique) (FSI); Group 3: Filtek Supreme XT Flow (FS Flow)+FSB; Group 4: FS Flow+FSI; Group 5: FS Flow+Ribbond (R)+FSB; Group 6: FS Flow+R+FSI; Group 7: FS Flow+everStick NET (E)+FSB; Group 8: FS Flow+(E)+FSI. All the teeth were then immersed in 0.5% basic fuchsin solution for 24 hours after thermocycling for 1000 cycles (5 degrees C and 55 degrees C). The teeth were sectioned longitudinally and observed under a stereomicroscope. In order to determine the polymerization shrinkage, another study was designed. In Group A, composite was applied as a bulk. In Group B, the resin composite was divided into two parts and Ribbond fiber was placed in the middle of the mass. In Group C, everStick NET fiber was placed inside the composite, as in Group B. Statistical analysis were performed by using one-way ANOVA and Tukey HSD tests for both microleakage and polymerization shrinkage (p < 0.05). Less microleakage was observed in groups where composites were applied by the incremental technique compared with those where the bulk technique was used (p < 0.05). The groups that used flowable composites showed significantly lower microleakage (p < 0.05). In groups where fiber nets were used, a significant decrease was determined in terms of microleakage (p < 0.05). Groups with fiber nets exhibited lower polymerization shrinkage (p < 0.05). Fiber nets decreased both microleakage and polymerization shrinkage. The incremental technique is an effective method for Class II composite restorations.

Effect of phosphoric acid etching and self-etching primer application methods on dentinal shear bond strength.

PURPOSE: To evaluate acid-etching effects prior to the application of self-etching primer and the effect of different primer application techniques on dentin shear bond strength (SBS). MATERIALS AND METHODS: Forty human third molar cervical regions were used in this study. The teeth were randomly divided into four groups (n=10) of different tooth surface conditions: group A: Clearfil Protect Primer applied gently (inactive) + Clearfil Protect Bond; group B: 38% phosphoric acid for 15 s, rinsed 15 s, and dried 15 s + Clearfil Protect Primer applied gently (inactive) + Clearfil Protect Bond; group C: Clearfil Protect Primer applied with agitation by microapplicator brush (active) + Clearfil Protect Bond; group D: 38% phosphoric acid for 15 s, rinsed 15 s, and dried 15 s + Clearfil Protect Primer applied with agitation by microapplicator brush (active) + Clearfil Protect Bond. The SBS test was performed with a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed with one-way ANOVA and Tukey HSD tests. RESULTS: The mean SBS values (MPa) and standard deviations are as follows: group A: 36.0 +/- 8.3; group B: 24.0 +/- 3.9; group C: 35.0 +/- 3.3; group D: 30.6 +/- 6.7. CONCLUSION: Acid etching decreased the SBS of the self-etching bonding system to dentin. Active primer application increased the SBS only in acid-etched groups.

Two-year follow-up of fractured anterior teeth restored with direct composite resin: report of three cases.

Thirty-five (case 1), 15 (case 2) and 22 (case 3)-year-old female patients presented to Yeditepe University Dental Faculty Clinic because of esthetic reasons. Fractures of maxillar central incisors including enamel and dentin were diagnosed. Beveling with diamond bur was performed in all four cases. Dentin was cleaned with tungsten carbid bur. The teeth were etched with 37% phosphoric acid, restored with an adhesive system and microhybrid composite. Finishing and polishing procedures were performed by discs (Sof-Lex) and burs. Restorations were found successful according to modified United States Public Health Service (USPHS) criteria after 2 years in terms of retention, color match, marginal discoloration, secondary caries, marginal adaptation, and surface texture.

Bond strengths of three different dentin adhesive systems to sclerotic dentin.

The two-fold aims of this study were: (1) to evaluate the microtensile bond strengths of different adhesive systems to sclerotic and sound palatal dentin; and (2) to observe the respective resin-dentin interfaces. Thirty extracted human incisor teeth were divided into two groups. Group I comprised sclerotic defects in the palatal zone. Group II comprised sound palatal dentin surfaces as control. Each group (n=15) was divided into three subgroups according to dentin adhesive systems: self-etch (Clearfil SE Bond), total-etch (Scotchbond Multi-Purpose Plus), and glass ionomer (Reactmer Bond) adhesive systems. The specimens were subjected to tensile forces. Obtained data were analyzed by two-way ANOVA and post hoc Duncan's test. Fracture sites and resin-dentin interfaces were observed using a light microscope and SEM. With sound dentin, Clearfil SE Bond showed a significantly higher bond strength than the other adhesives (p < 0.05). With sclerotic dentin, although there were no significant differences in bond strength among the adhesives groups (p > 0.05), the bond strength values of Clearfil SE Bond and Scotchbond Multi-Purpose Plus were significantly decreased. On resin-dentin interface observation, different images were presented by different bonding systems.

Qualitative and quantitative evaluation of enamel after various stripping methods.

INTRODUCTION: In this study, we investigated ultramorphology, surface roughness, and microhardness of permanent and deciduous tooth enamel after various stripping methods. METHODS: One hundred twenty deciduous and permanent teeth (n = 60 each) were used. Qualitative (scanning electron microscopy) and quantitative (surface roughness and microhardness tests) experiments were carried out in the following experimental groups: group 1, stripping disk; group 2, diamond-coated metal strip; group 3, stripping disk and Sof-Lex discs (3M-ESPE, Seefeld, Germany); group 4, diamond-coated metal strip and Sof-Lex discs; group 5 (chemical stripping), 37% orthophosphoric acid in conjunction with diamond-coated metal strip; group 6 (control), no stripping. Surface roughness values (Ra) for permanent and deciduous enamel were evaluated with Welch analysis of variance (ANOVA) and Tamhane tests, and Kruskal-Wallis and Mann-Whitney tests, respectively. Microhardness values were evaluated statistically with Kruskal-Wallis, 1-way ANOVA, and Duncan tests. RESULTS: Deciduous and permanent teeth showed similar results in terms of surface roughness and surface morphology. Groups 3 and 4 had the smoothest deciduous and permanent enamel surfaces, whereas chemical stripping (group 5) produced the roughest surfaces in both enamel types. Stripping did not lead to a significant change in the microhardness of permanent enamel. CONCLUSIONS: All stripping methods significantly roughened the enamel surfaces. Polishing the stripped surface with Sof-Lex discs decreased the roughness.

Clinical evaluation of posterior composite restorations in endodontically treated teeth.

OBJECTIVE: The purpose of this study was to evaluate the two year clinical performance of posterior composite restorations in endodontically treated premolars and molars using a hybrid composite (Filtek Z-250, 3M ESPE) and a total etch bonding system (Single Bond, 3M ESPE). METHOD AND MATERIALS: Thirty-nine class II restorations in endodontically treated premolars (n=11) and molars (n=28) of 27 patients (14 female, 13 male, mean age 36.51) in 16 maxillar and 23 mandibular teeth were placed by one operator. Restorations were evaluated by two experienced investigators at baseline, 12 months, and 24 months according to the modified United States Public Health Service (USPHS) criteria that included retention, color match, marginal discoloration, secondary caries, anatomic form, marginal adaptation, and surface texture. All restorations were able to be evaluated at baseline, 12 months, and 24 months. RESULTS: Paired samples t-test showed only marginal discoloration showed a statistically significant difference (p<0.05) at the end of 24 months, and no other significant differences were observed for the other variables examined over the duration of the study. None of the restored teeth showed periapical pathology at the end of 24 months. CONCLUSION: At two years, limited deterioration in marginal discoloration was detected. The clinical performance of posterior composite restorations in endodontically treated teeth using Filtek Z250 was found clinically acceptable after two years.

Microtensile bond strength of a filled vs unfilled adhesive to dentin using self-etch and total-etch technique.

OBJECTIVE: The purpose of this study was to evaluate the effect of a filled adhesive (One-Step Plus; Bisco) versus an unfilled adhesive (One-Step; Bisco) on the microtensile bond strength (muTBS) to dentin using total-etch (Uni-etch; Bisco) and self-etch (Tyrian SPE; Bisco) techniques. METHODS: Twenty extracted human third molars were ground flat to expose occlusal dentin. After the dentin surfaces were polished with 600-grit SiC paper, the teeth were randomly assigned to four groups according to the bonding agent and technique being used. Dentin surfaces were bonded with One-Step Plus+total-etch; One-Step Plus+self-etch; One-Step+total-etch and One-Step+self-etch. Composite buildups were performed with Clearfil AP-X (Kuraray Medical). Following storage in distilled water at 37 degrees C for 24 h, the bonded specimens were serially sectioned into 0.7 mm-thick slabs and then trimmed to hour-glass shapes with a 1 mm2 cross-sectional area (n=20). Microtensile bond strengths were determined using the EZ-test (Shimadzu) at a cross-head speed of 1 mm/min. Data were analyzed using two-way ANOVA and Tukey's post hoc test. RESULTS: There were no significant differences in the muTBS between One-Step Plus and One-Step adhesives when they were used with the total-etch and self-etch techniques (p>0.05). However with the total-etch technique both adhesives yielded significantly higher bond strength values than the self-etch technique (p<0.001). CONCLUSION: The filled adhesive One-Step Plus did not show any beneficial effect than the unfilled adhesive One-Step on the muTBS to dentin with total-etch and self-etch techniques. Irrespective from the adhesive type, self-etch technique revealed lower bond strengths than the total-etch technique.

Atraumatic restorative treatment with resin-modified glass ionomer material: short-term results of a pilot study.

OBJECTIVES: The aim of this study was to assess the feasibility of the resin-modified glass ionomer (RMGI) material in atraumatic restorative treatment (ART) approach and compare RMGI with the high-strength traditional glass ionomer cement (GIC) in permanent teeth with one or more surface-carious cavities. MATERIALS AND METHODS: This study was conducted in a village school in rural southeastern Anatolia, Turkey. The RMGI and GIC restorations with the ART technique were placed randomly employing a split mouth design. In addition, the ART approach was used when necessary for both primary and/or permanent teeth with no pulpal involvement and no perceived pain before treatment. Ninety-one fillings were placed on contralateral molar pairs of 37 children. Baseline and 6-month evaluation of the fillings were made with the classic ART, modified Ryge and USPHS criteria. RESULTS: Based on the ART criteria, 100% of RMGI and 92.4% of GIC restorations were classified as successful after 6 months, and the difference between the 2 groups was statistically significant (p=0.009). While marginal discoloration was the commonest failure in the RMGI group according to both the modified Ryge and USPHS criteria, unsatisfactory surface texture and low anatomic form were the commonly seen failures in the ART technique. CONCLUSION: Generally, for each rating system, RMGI exhibited better clinical performance than GIC in all categories, except for marginal discoloration. Results based on the 6-month evaluation show that RMGI can be an alternative material to the GIC.

Bonding to sound vs caries-affected dentin using photo- and dual-cure adhesives.

This study aimed to evaluate the microtensile bond strength (microTBS) of photo- and dual-cure adhesives to sound and caries-affected dentin using total- and self-etch techniques. Human third molars with occlusal caries were prepared as previously described by Nakajima and others (1995). Dentin surfaces were bonded with Optibond Solo Plus (Kerr; photo-cure adhesive) or Optibond Solo Plus + Dual-cure activator (Kerr; dual-cure adhesive) with total- and self-etch technique. Clearfil AP-X (Kuraray) was used for composite buildups. Following storage in distilled water at 37 degrees C for 24 hours, the teeth were sectioned into 0.7-mm thick slices to obtain sound and caries-affected dentin slabs, then trimmed to form hour glass shapes with a 1 mm2 cross-sectional area. The specimens were subjected to microtensile testing using EZ-test (Shimadzu) at 1 mm/minute. Data were analyzed using three-way ANOVA and Student's t-Test (p<0.05). Bond strengths to sound dentin with photo- and dual-cure adhesives using total- and self-etch techniques were significantly higher than those to caries-affected dentin. Dual-cure adhesive significantly decreased bond strengths both to sound and caries-affected dentin. The total-etch technique showed no beneficial effect on caries-affected dentin compared with the self-etch technique. Scanning electron microscopic observation of the resin-dentin interfaces revealed that hybrid layers in caries-affected dentin were thicker than those observed in sound dentin with photo- and dual-cure adhesives. Resin infiltration into dentinal tubules of caries-affected dentin was hampered by the presence of mineral deposits.

Physical properties of different composites.

The purpose of this study was to determine the flexural strength (FS), flexural modulus (FM), depth of cure (DC), polymerization shrinkage (PS), and microhardness (VH) of the following composites: Two packable composites--Filtek P-60 and Solitaire 2; One ion-releasing composite--riston AT; and Two hybrid composites--Charisma and Filtek Z-250. Data of the different tests conducted were obtained as follows: FS and FM data were determined with a universal-testing machine; Polymerization shrinkage was determined using the apparatus of Watts and Cash; Depth of cure was measured with a micrometer (Mitotuyo, UK); and Microhardness was measured with a Shimadzu Microhardness tester (500 g, 15 seconds). All data of the different tests were statistically analyzed by one-way variance analysis (ANOVA), which yielded the following results: Filtek Z-250 showed the statistically highest flexural strength and modulus values. Solitaire 2 exhibited the highest shrinkage, while the volumetric shrinkage results of Filtek Z-250 and Filtek P-60 ranked the lowest. For depth of cure, there were no statistically significant differences among all materials tested (p<0.05). Microhardness results revealed the following tendency: Filtek Z-250 = Filtek P-60 > Ariston AT = Solitaire 2 = Charisma.

In vitro effect of cavity disinfectants on the bond strength of dentin bonding systems.

OBJECTIVE: To evaluate the effect of two cavity disinfectants, a 2% chlorhexidine and a 1% benzalkonium chloride solution, on the shear and tensile bond strengths of dentin bonding systems to dentin. METHOD AND MATERIALS: Superficial dentin was exposed from 84 freshly extracted human third molars. The teeth were randomly assigned to two main groups according to the bonding agent used, either One Step or Optibond Solo. Each dentin bonding system had six test groups (three for shear, three for tensile testing), and each test group had a control and two cavity disinfectant groups. In the control groups, dentin bonding systems were applied after etching the dentin, whereas in the cavity disinfectant groups, dentin was conditioned and treated for 20 seconds with the disinfectants before applying the dentin bonding systems. A hybrid resin composite then was applied to all treated samples. After storage in distilled water at 37 degrees C for 24 hours, shear and tensile tests were performed. Data were analyzed using Kruskall-Wallis and Mann-Whitney U tests. RESULTS: The mean shear and tensile bond strengths of One Step and Optibond Solo were not significantly different from each other, and the cavity disinfectants also had no significant effects on shear and tensile bond strength values versus the controls. CONCLUSION: The results indicate that the use of 2% chlorhexidine and 1% benzalkonium chloride solutions as cavity disinfectants after etching the dentin did not affect the shear and tensile bond strengths of One Step and Optibond Solo.