The effect of different surface preparation methods and various aging periods on microtensile bond strength for composite resin repair.

AIMS: To evaluate the effect of various aging periods and different surface preparation methods on microtensile bond strength (µTBS) for composite repair. MATERIALS AND METHODS: One hundred twelve composite resin blocks were formed using a nanohybrid composite resin. The samples were distributed into four groups according to surface preparation methods (n = 28): control (sound composite blocks); Er, Cr: YSGG laser; air abrasion; silicone carbide. All samples were then divided into four subgroups according to various aging periods: (i) No aging, (ii) 10,000 thermocycling, (iii) 30,000 thermocycling, and (iv) 50,000 thermocycling. Following surface preparation and aging procedures, surface topography of one sample from each group was evaluated under scanning electron microscope (SEM). The repair composites were bonded to the sample surfaces, using a three-step etch&rinse adhesive. Finally, thirty beams of size 1 × 1 × 8 mm from each group were subjected to µTBS test and failure modes were determined. The data were analyzed using two-way ANOVA, Post-hoc Bonferroni, and Chi-square tests (P = 0.05). RESULTS: When different surface preparation methods were evaluated together, no aging and 10,000 thermocycling groups displayed higher µTBS values (P < 0.05). When all aging periods were evaluated together, the surface preparation with air abrasion provided higher µTBS (P < 0.05). The interactions of various aging periods with different surface preparation methods revealed significant variations in repair µTBS (P < 0.05). There were statistically significant differences on failure mode distributions among surface preparation methods (P < 0.001). SEM evaluations provided valuable outcomes that help to comment on the µTBS findings. CONCLUSIONS: Different surface preparation methods, various aging periods, and the interaction of both affected the repair µTBS of the tested nanohybrid composite resin.

Evaluation of tooth wear and associated risk factors: A matched case-Control study.

AIM: The aim of this case-control study was to compare the associated risk factors between adults with tooth wear (TW) and age- and sex-matched controls without TW. METHODS: Fifty participants with TW and 50 age- and sex-matched controls participated in this study. A questionnaire was prepared to assess oral healthcare and consumption of erosive food and drinks. All participants completed the diet analysis forms. Saliva characteristics were evaluated with GC Saliva-Check BUFFER test. Examiners measured the TW of case patients, using the TW index. Data were statistically analyzed using Chi-square and Mann-Whitney U-tests (P < 0.05). RESULTS: Individuals in the case group brush their teeth more often (P < 0.05). The difference in erosive food consumption between the case and control groups was significant (P < 0.05). There was no erosive effect of acidic food when consumed as a main meal or a snack (P > 0.05). Although there was no difference between stimulated saliva flow rate and buffering capacity between groups, the difference between the resting saliva flow rates and pH values was significant (P < 0.05). Although some wear was seen on buccal/labial surfaces of teeth, cervical and occlusal/incisal surfaces were scored higher. No TW was observed on palatal/lingual surfaces. The cervical surfaces of mandibular premolars and incisal surfaces of anterior teeth were most affected. CONCLUSION: Of the factors investigated, TW in the case group was correlated with consumption of acidic foods, lower salivary flow rate, and pH.

Clinical Follow-up of a Fissure Sealant Placed Using Different Adhesive Protocols: A 24-month Split-mouth Study.

The purpose of this study was to evaluate the retention rates of a fissure sealant placed using different adhesive protocols over 24 months. Twenty-four subjects with no restorations or caries received fissure sealants (Clinpro Sealant, 3M ESPE) placed using different adhesive protocols. A total of 292 sealants were placed as follows by two previously calibrated dentists using a table of random numbers (n=73): group I, acid-etch/without adhesive; group II, with a self-etch adhesive (Adper Easy Bond, 3M ESPE); group III, with an etch-and-rinse adhesive (Adper Single Bond 2, 3M ESPE); group IV, with acid + self-etch adhesive (Adper Easy Bond). Two other calibrated examiners independently evaluated the sealants at baseline and at six-, 12-, 18-, and 24-month recalls. Each sealant was evaluated in terms of caries formation being present or absent and retention using the following criteria: 1 = total retention, 2 = partial loss, and 3 = total loss. Pearson's χ2 test was used to evaluate differences in retention rates among the sealants for each evaluation period. At the end of 24 months, total retention rates were 57.5%, 27.4%, 84.9%, and 76.7% in the acid-etch, self-etch adhesive, etch-and-rinse adhesive, and acid + self-etch adhesive groups, respectively. Although there were no statistically significant differences between the retention rates among the adhesive protocols at 6 months ( p=0.684), significant differences were observed at the 12-, 18-, and 24-month evaluations. At 24 months, the lowest retention rates were observed in the self-etch group ( p<0.05). No caries development was observed in any of the groups. The retention rate of sealants placed using self-etch adhesive was poor compared with the other groups.

Clinical Evaluation of a Silorane- and a Methacrylate-Based Resin Composite in Class II Restorations: 24-Month Results.

OBJECTIVE: To compare the 24-month clinical performance of two different resin composites in class II slot restorations. METHODS AND MATERIALS: Thirty-seven patients having at least two approximal carious lesions were enrolled in the study. A total of 116 teeth (58 pairs) were restored with either a silorane-based composite (Filtek Silorane) and its self-etch adhesive (Silorane Adhesive System, 3M ESPE) or a methacrylate-based packable resin composite (X-tra Fil) and its self-etch adhesive (Futurabond NR, VOCO GmbH) according to the toss of a coin. The restorations were evaluated at baseline and at six-, 12-, and 24-month recalls by two calibrated examiners according to the modified US Public Health Service criteria. The comparison of the two restorative materials for each category was performed with the Pearson chi-square test. Within group differences of the materials at different recall times were compared using the Cochran Q and Friedman tests. Bonferroni-adjusted McNemar test was used when significant difference was found (p<0.05). RESULTS: After 24 months, no statistically significant differences were found between the two restorative materials for the criteria evaluated. CONCLUSIONS: Both silorane- and methacrylate-based resin composites showed clinically acceptable performance in class II slot restorations after 24 months.

Fracture Resistance of Endodontically Treated Teeth Restored With Bulk Fill, Bulk Fill Flowable, Fiber-reinforced, and Conventional Resin Composite.

The aim of this in vitro study was to evaluate the fracture resistance of endodontically treated teeth restored with different types of restorative resins. METHODS AND MATERIALS: Seventy-two sound maxillary premolar teeth were randomly divided into six groups (n=12). The teeth in the first group were left intact and tested as unprepared negative control (group I) specimens. The teeth in the remaining five groups were prepared with MOD cavities and endodontically treated. The teeth in one of the five groups (positive control group II) were unrestored. The rest of the prepared cavities were restored as follows: group III: bulk fill resin composite/Filtek Bulk Fill (3M ESPE); group IV: bulk fill flowable resin composite + nanohybrid/SureFil SDR Flow + Ceram.X Mono (Dentsply); group V: fiber-reinforced composite + posterior resin composite/GC everX posterior + G-aenial posterior (GC Corp.); and group VI: nanohybrid resin composite/Tetric N-Ceram (Ivoclar/Vivadent). Each restorative material was used with its respective adhesive system. The restored teeth were stored in distilled water for 24 hours at 37°C and were then thermocycled (5-55°C, 1000×). Specimens were subjected to a compressive load until fracture at a crosshead speed of 0.5 mm/min. The data were analyzed using one-way analysis of variance followed by the post hoc Tukey honestly significantly different test (p<0.05). RESULTS: Sound premolar teeth (group I negative control) showed significantly higher fracture resistance than did the other tested groups (p<0.05). No statistically significant differences were found in the fracture resistance values of the restored groups (groups III, IV, V, and VI) (p>0.05). The lowest values were obtained in the positive control group (group II); these values were significantly lower than those of the other groups (p<0.05). CONCLUSION: The fracture resistance values of endodontically treated teeth restored with either bulk fill/bulk fill flowable or fiber-reinforced composite were not different from those restored with conventional nanohybrid resin composite.

Three-year clinical evaluation of different restorative resins in class I restorations.

The aim of the present study was to evaluate the three-year clinical performance of a nanofilled resin composite, a packable resin composite, and silorane-based resin restorations in Class I occlusal cavities. Twenty-eight patients with at least three similar-sized occlusal lesions in molar teeth participated in the study. A total of 84 Class I occlusal restorations were placed: 28 with nanofilled resin composite (Filtek Supreme), 28 with packable resin composite (P60), and 28 with silorane-based resin (Filtek Silorane). Filtek Supreme and P60 were used with their respective etch-and-rinse adhesive system, Adper Single Bond 2, and Filtek Silorane was used with its respective self-etch adhesive, Filtek Silorane Adhesive. All restorations were placed by the same operator. The restorations were evaluated at baseline, at six months, and annually for three years according to modified US Public Health Service criteria by two calibrated examiners who did not know which restorative resin had been used. The three restorative materials for each category were compared using the χ (2) test at a significance level of 0.05. Cochran's Q test was used to compare the changes across the five time points for each restorative material. McNemar's test followed by Bonferroni adjustment was used when significance differences were found. At the end of the three years, 60 restorations were evaluated in 20 patients, with a recall rate of 71.4%. The retention rate was 100% for all restorative resins. Eight restorations from the P60 group, ten from the Filtek Supreme group, and nine from the Filtek Silorane group were rated Bravo for marginal discoloration. For marginal adaptation, three P60, five Filtek Supreme, and 11 Filtek Silorane restorations were rated Bravo. No statistically significant differences in overall clinical performance were found between the restorative materials except for marginal adaptation. P60 showed the best marginal adaptation at the end of the three years. No differences were observed between the restorative resins for any of the evaluation criteria tested (p>0.05). None of the restorations showed postoperative sensitivity, secondary caries, or loss of anatomic form. All restorative resins performed equally well in clinical conditions during the three-year evaluation, and no significant differences were found among them, except for marginal adaptation, in which P60 showed superior results.

Polymerization shrinkage of different types of composite resins and microleakage with and without liner in class II cavities.

AIM: To determine the volumetric polymerization shrinkage of four different types of composite resin and to evaluate microleakage of these materials in class II (MOD) cavities with and without a resin-modified glass ionomer cement (RMGIC) liner, in vitro. MATERIALS AND METHODS: One hundred twenty-eight extracted human upper premolar teeth were used. After the teeth were divided into eight groups (n=16), standardized MOD cavities were prepared. Then the teeth were restored with different resin composites (Filtek Supreme XT, Filtek P 60, Filtek Silorane, Filtek Z 250) with and without a RMGIC liner (Vitrebond). The restorations were finished and polished after 24 hours. Following thermocycling, the teeth were immersed in 0.5% basic fuchsin for 24 hours, then midsagitally sectioned in a mesiodistal plane and examined for microleakage using a stereomicroscope. The volumetric polymerization shrinkage of materials was measured using a video imaging device (Acuvol, Bisco, Inc). Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: All teeth showed microleakage, but placement of RMGIC liner reduced microleakage. No statistically significant differences were found in microleakage between the teeth restored without RMGIC liner (p>0.05). Filtek Silorane showed significantly less volumetric polymerization shrinkage than the methacrylate-based composite resins (p<0.05). CONCLUSION: The use of RMGIC liner with both silorane- and methacrylate-based composite resin restorations resulted in reduced microleakage. The volumetric polymerization shrinkage was least with the silorane-based composite.

Clinical evaluation of different adhesives used in the restoration of non-carious cervical lesions: 24-month results.

BACKGROUND: The aim of this study was to compare after 24 months the clinical performance of cervical restorations placed with the use of an etch-and-rinse and an all-in-one adhesive. METHODS: Twenty-four patients with at least one pair of non-carious cervical lesions participated in this study. One hundred and twenty-three cervical lesions were restored (62 etch-and-rinse adhesive, Solobond M; 61 all-in-one adhesive, Futurabond NR). A nanohybrid resin composite, Grandio, was used as the restorative material. Restorations were evaluated according to modified USPHS criteria by two independent examiners. The survival rates of the restorations were calculated by the Kaplan-Meier estimator and log-rank test. The restorations in each category were compared using the Pearson chi-square test, while the performance of restorations at the baseline and at each recall time was evaluated by McNemar's test (p < 0.05). RESULTS: The recall rate of patients was 100%. The retention rates were 82% and 75% at 6 months and 77% and 62% at 12 months for Solobond M and Futurabond NR, respectively. At the 24-month recall, the retention rate was 69% for Solobond M and 49% for Futurabond NR, and this difference was statistically significant (p < 0.05). No statistically significant difference was found for colour match, marginal staining, or marginal adaptation between the adhesives (p > 0.05). None of the restorations had secondary caries, loss of anatomical form, or surface texture changes. CONCLUSIONS: Cervical restorations placed with an etch-and-rinse adhesive showed higher retention than an all-in-one adhesive.

Cuspal deflection in premolar teeth restored using current composite resins with and without resin-modified glass ionomer liner.

AIM: To evaluate the effects of four different types of composite resins and a resin modified glass ionomer cement (RMGIC) liner on the cuspal deflection of large MOD cavities in vitro. MATERIALS & METHODS: One hundred twenty-eight extracted human upper premolar teeth were used. After the teeth were divided into eight groups (n=16), standardized large MOD cavities were prepared. The distance between cusp tips was measured before and after the cavity preparations with a digital micrometer. Then the teeth were restored with different resin composites (Filtek Supreme XT, Filtek P60, Filtek Z250, Filtek Silorane - 3M ESPE, St Paul, MN, USA) with and without a RMGIC liner (Vitrebond, 3M ESPE, St Paul, MN, USA). Cuspal deflection was measured 5 min, 24 h, and 48 h after the completion of restorations. The data were statistically analyzed with Friedman and Kruskal Wallis tests. RESULTS: A significant reduction in cuspal deflection was observed in Filtek Silorane restorations with and without RMGIC liner (p<0.05). In all restored teeth, the distance between cusps was reduced but they did not return to their original positions during the 48 h period. All teeth showed cuspal deflection, but placement of RMGIC liner reduced it. CONCLUSION: The use of silorane-based composites and the placement of RMGIC liner under the composite resin restorations resulted in significantly reduced cuspal deflection.

Bond strength of different adhesive systems to dental hard tissues.

This study compared the shear bond strengths of different adhesive systems to enamel and dentin of different depths. The adhesive systems used were: Single Bond one-bottle total-etch; AQ Bond one-step self-etching, Clearfil SE Bond two-step self-etching and Tyrian SPE/One-step Plus two-step self-etching. Eighty extracted non-carious human mandibular molars were mounted in self-curing resin and the occlusal surfaces were ground with a mechanical grinder to obtain flat occlusal enamel surfaces. After applying the adhesive systems, a plastic tube was attached to the enamel surfaces. The tube was filled with a universal hybrid resin composite, which was then polymerized. The specimens were stored in water at 37 degrees C for 24 hours. Shear bond testing was carried out using an Instron Universal testing machine with a crosshead speed of 1 mm/minute. The occlusal enamel of the 80 teeth was removed to determine the bond strengths of the adhesives to superficial dentin. To obtain deep dentin, the same teeth were ground deep towards the pulp, with the remaining dentin thickness approximately 0.7 mm. The adhesives and restorative material were then applied to the prepared dentin surfaces following the methodology described above. For occlusal enamel surfaces, the bond strength of Single Bond was significantly higher than the other adhesives. Single Bond, Clearfil SE Bond and Tyrian SPE/One-step Plus performed equally when bonded to superficial dentin; the lowest bond strength was obtained with AQ Bond. On deep dentin, the highest bond strengths were obtained with Clearfil SE Bond. For each adhesive system, shear bond strength to enamel was statistically higher than it was to either superficial or deep dentin. There were no significant differences between shear bond strengths to superficial versus deep dentin, regardless of adhesive.

Fracture resistance of class II packable composite restorations with and without flowable liners.

This study evaluated fracture resistance in class II slot packable composite restorations with and without the use of a flowable composite liner. A conventional microhybrid composite was used as a control. Thirty-six sound, caries-free human mandibulary molar teeth were used. Separate mesio-occlusal and disto-occlusal class II slot cavity preparations were made in each tooth. The prepared teeth were randomly divided into three groups of 12 teeth. Two packable composites (Surefil, Filtek P60) and one microhybrid composite (Filtek Z250) with their respective manufacturer's bonding agents were used to restore the cavities. One side of each tooth was restored with composite alone, while the other side was restored with the composite lined with that manufacturer's flowable liner. The marginal ridges of the restorations were loaded at an angle of 13.5 degrees to the long-axis of the tooth in an Instron Testing Machine until failure. The data were analysed using a one-way anova. There was no significant difference in fracture resistance between composite restorations with and without flowable liners.

Bond strength of a self-etching adhesive system to caries-affected dentin.

This in vitro study evaluated the microtensile bond strengths of sound versus caries-affected dentin using a self-etching adhesive system, Clearfil SE Bond, with or without additional acid pre-conditioning. Extracted human mandibular molars with occlusal caries extending halfway through the dentin were used. In the first group, the teeth were bonded with the self-etching adhesive Clearfil SE Bond according to the manufacturer's instructions. In the second group, prepared dentin surfaces were etched with 37% phosphoric acid prior to applying the same self-etching adhesive. After the bonding procedure, all specimens were built up with composite resin and stored in water for 24 hours. The teeth were serially sectioned vertically into 0.7-mm slabs and trimmed into an hourglass shape for measuring microtensile bond strength. Each specimen was attached to a Bencor device and stressed in tension at a crosshead speed of 1 mm/minute. Statistical analysis was performed using two-way ANOVA and the Tukey HSD test (p<0.05). The microtensile bond strengths of Clearfil SE Bond to sound dentin (32.9) were significantly higher than to caries-affected dentin (15.9). In the second group where acid etching was performed prior to applying Clearfil SE Bond, there were no statistically significant differences between the microtensile bond strengths of sound (19.2) and caries-affected dentin (16.3). While bond strengths to sound dentin were decreased by using additional acid etching prior to applying Clearfil SE Bond, this procedure revealed no statistically significant differences in bond strengths for the caries-affected dentin.

In vitro comparison of the efficacy of Carisolv and conventional rotary instrument in caries removal.

The purpose of this in vitro study was to compare the efficacy of a new chemomechanical caries removal agent, Carisolv (MediTeam AB, Sävedalen, Sweden), with conventional slow-speed rotary instrument (bur). Fourteen extracted human molar teeth with deep dentine caries and no enamel coverage were selected for the study. Their laser fluorescence values were over 30 (DIAGNOdent; KaVo, Biberach, Germany). After the teeth were sectioned through the centre of the carious lesion, one half was removed with conventional drilling (bur); the other half was removed with Carisolv gel. Removal of carious dentine was continued until the lesion was deemed caries-free by visual and tactile criteria. The preparation time for each caries removal technique was also noted. The two halves of each tooth were fixed in 10% buffered-formaldehyde for 1 week. They were then decalcified, dehydrated and embedded in paraffin blocks for histological studies. After taking serial sections of 5 microm thickness, sections were mounted on glass slides, deparaffinized, dehydrated and stained with toluidine blue for observation under a light microscope. Each section was examined for the presence of bacteria. Complete removal of caries was achieved in 13 (93%) of 14 conventionally prepared teeth, and 5 (36%) of 14 chemomechanically prepared teeth (P < 0.05). Mean (+/-SD) time for caries removal was 272 s (+/-53.3) with Carisolv, and 116 s (+/-49.4) with drilling. The results of this study suggest that conventional rotary instrument (bur) was more effective than Carisolv in removal of carious tissue and also takes shorter time.

Effect of finishing and polishing procedures on the surface roughness of new tooth-coloured restoratives.

The purpose of this study was to evaluate the effect of various finishing and polishing procedures on the surface roughness of three new tooth-coloured restorative materials. The materials included a hybrid composite resin (Filtek Z250), a packable composite resin (Filtek P60), and an ormocer (organically modified ceramic) (Definite). Thirty-two specimens of each material were prepared and randomly divided into four finishing and polishing groups (n = 8): (i) diamond bur/silicone polishers, (ii) diamond bur/Sof-Lex discs, (iii) carbide bur/silicone polishers, (iv) carbide bur/Sof-Lex discs. Average surface roughness (Ra) in micrometers was measured with a Mitutoyo Surftest-402 Surface Roughness Tester and the data compared using anova, at P < or = 0.05. Surface topography was also assessed using the scanning electron microscope (s.e.m) from samples of each group. The Mylar strip produced the smoothest surface and finishing/polishing procedures; (ii) and (iv) were significantly smoother than (i) and (iii). The lowest variability in initial surface roughness between materials was also observed with ormocer group.

Three-year clinical evaluation of a resin modified glass-ionomer cement and a composite resin in non-carious class V lesions.

The purpose of this study was a 3-year clinical evaluation of a resin modified glass-ionomer and a composite resin restorative material in non-carious class V lesions. In 24 patients 98 non-carious class V lesions were restored with either a resin modified glass-ionomer (Vitremer), or a composite resin restoration (Z100). The restorations were clinically evaluated after 6, 12, 24 and 36 months with the US Public Health Service criteria. At 3 years, 88 teeth of 21 patients were evaluated. All restorations were rated clinically acceptable for colour match, marginal discoloration, marginal adaptation and anatomical form. Restoration retention of both groups was high without any statistically significant difference. However, Vitremer restorations showed a lower incidence of Alfa scores for colour match and marginal discoloration than Z100 restorations (P < 0.05).

Effects of preparation designs and adhesive systems on retention of class II amalgam restorations.

PURPOSE: This study evaluated the effects of three preparation designs and the influence of an adhesive system in Class II amalgam restorations when a load was applied directly to the marginal ridge. MATERIAL AND METHODS: Seventy-two sound caries-free maxillary molars were divided into 6 groups of 12 teeth. In groups 1 and 4, the preparation had an extension through the occlusal groove, whereas the other four groups used a proximal slot (box-only) preparation. Groups 2 and 5 had facial and lingual retention grooves that extended from the gingival floor to the occlusal surface, and groups 3 and 6 had slots without grooves. Teeth in groups 1, 2, and 3 were restored with amalgam and groups 4, 5, and 6 were restored with resin bonded amalgam. The marginal ridges of the restorations were loaded at an angle of 13.5 degrees to the long axis of the tooth in an Instron testing machine until failure. RESULTS: Analysis of mean failure loads indicated that proximal slot preparations with retention grooves or occlusal extensions were statistically equivalent but significantly greater than proximal slots without grooves. The addition of an adhesive system improved fracture values for all three types of preparations. CONCLUSIONS: When proximal caries was diagnosed and no occlusal caries was evident, a proximal slot amalgam restoration combined with retention grooves and an adhesive system was the appropriate choice.