Comparative Evaluation of the Effects of Ozone,Diode Laser,and Traditional Cavity Disinfectants on Microleakage

Aim: This study aimed to evaluate the effects on microleakage of the application of ozone gas, laser and traditional cavity disinfection under in vitro conditions.

Material and Methods: Ninety third-molar teeth extracted for various reasons were used in this study. All the teeth were prepared with a standard V cavity on the buccal surface. Then the teeth were randomly allocated to one of 6 groups of 15 teeth; Group 1 benzalkonium chloride, Group 2 chlorhexidine gluconate, Group 3 sodium hypochloride, Group 4 diode laser, Group 5 ozone gas, Group 6 control group- no disinfection was applied. Primer was applied to the cavities, then bond and 10-s polymerization. Clearfil AP-X was used in the cavities as a hybrid composite and polymerized for 20 s. The samples then underwent 1000 thermal cycles of 30-s application, in baths at temperatures between 5 ± 2 °C and 55 ± 2 °C. All the samples were stirred in 0.5% basic phuxine solution and the sections taken under stereomicroscope were examined and photographed at 15 × magnification. SEM analysis was made and the obtained results were statistically evaluated with the Kruskal–Wallis test.

Results: No significant difference was seen between the groups in respect of the microleakage values of both the occlusal and gingival edges (p < 0.05). Comparison of the microleakage values of the occlusal and gingival edges of the groups determined the least leakage to be in the ozone group (p < 0.05).

Conclusion: No statistical significance was determined between the groups. However, the mean least microleakage was found in the ozone group and the highest amount in the control group.     

Microleakage in class V cavities prepared using conventional method versus Er:YAG laser restored with glass ionomer cement or resin composite

This study evaluated the effect of tooth preparation method (diamond bur vs. Er:YAG laser) on the microleakage levels of glass ionomers and resin composite. Human permanent premolars (N = 80) were randomly divided into two groups (n = 40). Cavities on half of the teeth were prepared using diamond bur for enamel and carbide bur for dentin and the other half using Er:YAG laser. The teeth were randomly divided into four groups according to the restoration materials, namely (a) ChemFil Rock (CFR), (b) IonoluxAC (IAC), (c) EQUIA system (EQA) and one resin composite (d) AeliteLS (ALS) (n = 10 per group). Microleakage (μm) was assessed at the occlusal and gingival margins after dye penetration (0.5% basic fuchsine for 24 h). On the occlusal aspect, while the cavity preparation types significantly affected the microleakage for CFR (p = 0.015), IAC (p = 0.001) glass ionomer restorations, it did not show significant effect for glass ionomer EQA (p = 0.09) and resin composite ALS (p = 0.2). Er:YAG laser presented less microleakage compared to bur preparation in all groups except for EQA. On the gingival aspect, microleakage decreased significantly for CFR (p = 0.02), IAC (p = 0.001), except for EQA where significant increase was observed (p = 0.001) with the use of Er:YAG laser. Microleakage decrease was not significant at the gingival region between diamond bur and Er:YAG laser for ALS (p = 0.663). At the occlusal and gingival sites in all groups within each preparation method, microleakage level was not significant.     

Comparison of microleakage of a multi-mode adhesive system with contemporary adhesives in class II resin restorations

Aim: The aim was to compare the microleakage of resin composite bonded with different adhesive systems in class-II cavities at enamel or dentine margins. Material and methods: 60 extracted human molar teeth received slot cavity preparations on mesial and distal surfaces (mesial cervical margin was prepared in enamel and distal in dentine). They were randomly divided into five groups (n?=?12) according to the adhesive system: Group-A: Silorane Bond (S), Group-B: Adper Single Bond 2 (SB), Group-C: Clearfil SE Bond (CSE), Group-D: Single Bond Universal (USel) (selective etch-and-rinse), Group-E: Single Bond Universal (USE) (all-in-one). The preparations were restored using the same resin composite (Filtek Ultimate) except Group A which was restored by Silorane composite. The teeth were thermocycled, immersed in dye, sectioned, and dye penetration was evaluated quantitatively using image analysis. The data were analyzed using the two-way analysis of variance and Bonferroni test. Results: In all groups, there was no statistically significant difference between enamel margins at occlusal and gingival sites (p?>?0.05). The statistical difference between Group-A (S) and Group-B (SB) was significant at all margins. Group-B (SB) presented the greatest microleakage amounts at all margins and the highest scores were obtained in the dentine. Likewise, SB demonstrated statistically significant differences between dentine and enamel margins (occlusal and gingival)(p?<?0.05). Conclusion: All adhesive systems showed similar microleakage values between enamel margins in occlusal and gingival regions. However, when the gingival margin is located in the dentine, etch&rinse adhesive systems may not be a choice in terms of microleakage prevention.     

Effect of desensitizers on the microleakage of previously restored Class V resin composite restorations

Objectives: The aim of this in vitro study was to evaluate the effect of different desensitizers’ application on the microleakage of previously restored Class V composite resin restorations.

Materials and methods: Class V cavities were prepared on the buccal surfaces of 40 extracted human third molars. Forty box-shaped cavities were divided into four groups, based on the desensitizers used (n = 10). All teeth were restored with the same bonding agent and composite material. No desensitizer was applied in the control group. In the experimental groups, BisBlock, Gluma and Universal bonding agents were the desensitizers. The desensitizers were applied after completion of composite restorations according to manufacturers’ instructions. All specimens were then thermocycled at 5–55 °C, with a 10-s dwell time for 500 cycles. The samples were then immersed in 0.5% methylene blue dye for 24 h, sectioned into two equal halves, evaluated for microleakage using a stereomicroscope at 30× magnification and scored on a scale of 0–3. The data were analysed using the Kruskal–Wallis test at the significance level p < 0.05.

Results: There were no significant differences in microleakage after desensitizer application (p > 0.05). However, based on the obtained numerical values in our study, while the BisBlock and bonding groups showed lower microleakage at the occlusal margin, BisBlock, Gluma and bonding group showed lower microleakage at the gingival margin compared to the control group.

Conclusions: The application of desensitizers as a post-treatment option could be considered an advisable procedure to minimize microleakage.     

Can Dentin Surfaces Be Bonded Safely With Ozone and Boric Acid?

The aim of this study is to evaluate the effect of different cavity disinfectants on shear bond strength. In this study, 60 caries-free human molar teeth were used. Smooth dentin surfaces were revealed by cutting occlusal enamel and a standard smear layer was obtained by using 600-grid sandpaper. Specimens were randomly assigned to four groups according to the disinfectant used: Group 1: Control (no disinfectant); Group 2: Ozone; Group 3: Chlorhexidine, Group 4: Boric acid. Specimens were bonded using S3 Plus Bond and the composite buildups were created by using composite resin according to the manufacturer’s instructions. After specimens were kept for 24 h, at 37 °C in distilled water, the shear bond strength test was measured with a universal test machine. The highest bond strength values were observed in the control group. The bond strength was significantly lower in the chlorhexidine, and boric acid-treated groups than it was in the control group (respectively, p = 0.046 and p = 0.028); however, no significant difference in the bond strength was observed between the ozone group and the control group (p = 0.444). The ozone group was detected as having the best shear bond strength values in groups which were applied to cavity disinfectants.     

The effects of self-etch bio-active dental adhesive systems on bacterial microleakage

The aim of this in vitro study was to evaluate the effects of bio-active and non-bio-active self-etch adhesive sytems on bacterial microleakage of class II box cavities with restoration margins in dentin. Two bio-active (Clearfil Protect Bond and F1 Bond II) and two nonbio-active (Clearfil SE Bond and Clearfil s3 Bond) adhesive systems were selected for the study. Eighty mesial and distal class II box cavities were prepared on fourty sound human third molar teeth. The teeth were then divided into four groups with 10 teeth in each group. Groups were restorated using different adhesive systems. The restored specimens were immersed into a culture medium containing streptococcus mutans for bacterial microleakage test. Serial sections of the specimens were used to evaluate the bacterial lekage by using light microscope. The data obtained from the test of bacterial microleakage was evaluated using 2-way mixed analysis of variance (p < 0.05). Statistical analysis showed significant differences between the groups (p < 0.05). Nevertheless it was observed that none of the tested adhesive systems including the bio-active ones were successfull in eliminating bacterial microleakage.     

Effect of 2% chlorhexidine gluconate cavity disinfectant on microtensile bond strength of tooth-coloured restorative materials to sound and caries-affected dentin

This study evaluated the effect of 2% chlorhexidine gluconate-based cavity disinfectant (CHX) on the microtensile bond strength (μTBS) of glass ionomer, resin-modified glass ionomer and packable resin composite to sound and caries-affected dentin. Sound and occlusal caries-affected human third molars (N?=?36, n?=?3 per group) were randomly divided into three experimental groups to receive one of the following restorative materials. (a) Glass ionomer (Ketac Molar, 3 M ESPE; GI), (b) resin-modified glass ionomer (Vitremer, 3 M ESPE; RMGI) and (c) packable resin composite (Surefil, Dentsply; PRC) with a bonding agent (Prime Bond NT, Dentsply De Trey). Caries was removed using a caries-detecting dye (Caries Detector, Kuraray Medical Ltd.) and flat dentin surfaces were achieved by finishing up to 1200-grit silicon carbide abrasive. Half of the teeth in each group received 2% CHX (Consepsis, Ultradent). Dentin surfaces were built-up with the respective materials incrementally and were sectioned with a slow-speed saw into multiple beams. The beams were subjected to μTBS test (0.5 mm/min) in a Universal Testing Machine. The data were analysed using two-way analysis of variance and Tukey’s tests. For each restorative material, μTBS results were not affected by the application of CHX (p?>?0.05) on both sound and caries-affected dentin (p?>?0.05). PRC in combination with the corresponding bonding agent showed significantly higher results (p?<?0.05) than those of GI and RMGI, on sound and caries-affected teeth, respectively. Cohesive failure in dentin was not observed in any of the groups. The use of 2% chlorhexidine-based cavity disinfectant did not impair the adhesion of the restorative materials tested to either sound or caries-affected dentin.     

The effect of bulk-fill flowable composites on the fracture resistance and cuspal deflection of endodontically treated premolars

The aim of this study was to evaluate the effect of bulk-fill flowable composites on cuspal deflection and fracture resistance of endodontically treated teeth. Forty-two maxillary premolars were subjected to endodontic treatment followed by the preparation of mesioocclusodistal cavities. Teeth were divided into six groups according to restorative materials as follows: Group 1: Clearfil Majesty Flow and Clearfil Majesty Posterior; Group 2: Venus Bulk Fill and Clearfil Majesty Posterior; Group 3: Clearfil Majesty Posterior; Group 4: Vertise Flow and Clearfil Majesty Posterior; Group 5: SDR and Clearfil Majesty Posterior; and Group 6: x-tra base and Clearfil Majesty Posterior. A single-step self-etch adhesive (OptiBond All-in-One) was applied to all groups, except Group 4. The cavities were restored with a centripetal incremental insertion technique and flowable composites using a 2-mm-thick base material, except for Group 3. The distance between cusp tips was measured before and after the cavity preparations, after the restorations, and after thermal cyclus with a digital micrometer. After measuring, each tooth was subjected to compressive loading with a stainless steel ball (4 mm diameter) perpendicular to the occlusal surface with a crosshead speed of 1 mm/min, and mean loads necessary to fracture were recorded in Newtons. The data were statistically analyzed by Kruskal–Wallis test. No statistically significant differences were found between groups in fracture strength or cuspal deflections (p > 0.05). Bulk-fill flowable composite bases did not change the cuspal deflection or fracture resistance of endodontically treated teeth, compared with that of a conventional flowable base and conventional resin composite.     

Cuspal deflection and microleakage in pre molar teeth restored with bulk-fill resin-based composites

The aim of this study was to assess the cuspal deflection and cervical microleakage of premolar teeth filled with a bulk-fill composite resin or bulk-fill flowable composite resin base, and comparison between them and a conventional dimethacrylate and a silorane-base composite resin. Forty maxillary premolar teeth were divided into four groups (n?=?10), standardized large mesio-occluso-distal (MOD) cavities were prepared. The distance between cusp tips was measured before and after the cavity preparations with a digital micrometer. In Group 1 Quixfil was used with bulk-fill technique. Teeth in Group 2 were restored to within 2?mm of palatal cusp in a single increment with x-tra base. The remaining occlusal cavity was restored with GrandioSO. In Groups 3 and 4, the teeth were incrementally restored with GrandioSO and Filtek Silorane, respectively. Cuspal deflection was measured 5?min, 24?h, 1 week, and 2 weeks after the completion of restorations. Each restored tooth was subjected to thermocycling regime, and microleakage was assessed. Data were analyzed with Kruskal–Wallis and Mann Whitney U tests (p?<?0.05). Groups restored with bulk-fill composites (Groups 1 and 2) showed similar cuspal deflection with the group restored incrementally with GrandioSO. A significant reduction in cuspal deflection was observed in Filtek Silorane restorations. None of the groups showed complete prevention of dye penetration. Group 2 showed the best marginal sealing. In Conclusion, conventional composite resin applied by incremental technique caused cuspal deflection similar to that of bulk-fill composites used as restorative or base. The flowable bulk-fill composites were superior to others in preventing microleakage.     

Long-term microleakage trends in access cavities conditioned with phosphoric acid and deproteinizing agent for root-canal-treated teeth: an investigation of fluid filtration and microscopy analysis

This study evaluated the long-term microleakage of access cavities conditioned with phosphoric acid and deproteinizing agents for root-canal-treated teeth using fluid filtration and microscopical analysis. Occlusal surfaces of extracted human mandibular premolars (N = 90) were removed leaving a 4 mm coronal length from the cemento-enamel junction. After root canal treatment, the specimens were randomly divided into four experimental groups (n = 21) and the remaining teeth were used for positive control group (n = 6): SB: 35% H₃PO₄ + Adper Single Bond 2; SSB: 35% H₃PO₄ + 5.25% NaOCl + 10% Sodium ascorbate (C₆H₇NaO₆) + Adper Single Bond 2; XP: 35% H₃PO₄₊XP Bond; SXP: 35% H₃PO₄₊5.25% NaOCl + 10% Sodium ascorbate + XP Bond. All cavities were restored with a resin composite (Filtek Z250). After removing the root filling from the apical side, teeth were subjected to fluid filtration test for 1 week, 6 and 12 months followed by ×2500 thermocycling after 1st week and 6th months each. Data were analyzed using one-way ANOVA and Dunnet T3 tests (α = 0.05). SEM analyses were carried out after each microleakage evaluation in two random teeth from all groups. Microleakage values in groups SB and XP presented no significant difference in any of the evaluated period (p > 0.05). Microleakage results of SXP (0.01665) group showed significant difference compared to XP (0.03377) and SB (0.03049) groups after 12 months. SSB group (0.00901) showed significantly less microleakage among all other groups (0.01665–0.03377) (p < 0.05). Prior to endodontic treatment, in access cavities, acid etching with 35% H₃PO₄ followed by the application of NaOCl and sodium ascorbate completely destroyed the collagen layer, reducing the microleakage and resin–dentin interface degradation up to 12 months.     

The role of surface-sealant application on bond effectiveness of all-in-one self-etch adhesives

Purpose: To examine microleakage around Class-V restorations bonded with 3 current all-in-one adhesive systems in the presence or absence of surface-sealant in different evaluation groups.

Materials and Methods: Clearfil S3 Bond, G-Aenial Bond, and Optibond All-in-One (AiO), were used in the Class-V cavities in accordance with the manufacturer’s instructions (control group) or were additionally combined with Fortify Plus surface-sealant (surface-sealant group). The two main treatment groups of the dentin adhesives were subdivided into four different evaluation groups (24 h, 6 months, 12 months, and 12 months with two applications); the teeth were immersed in 0.5% methylene blue dye solution for 24 h. Samples were then sectioned longitudinally in a bucco-lingual direction and evaluated for microleakage under a stereomicroscope. Dye penetration was scored at the enamel (occlusal) and dentin (gingival) margins.

Results: Microleakage scores were greater at the dentin margins compared with the enamel margins for Clearfil S3 Bond in all evaluation groups, whereas no difference was observed between enamel and dentin microleakage for Optibond AiO. Using Fortify Plus in the enamel margins decreased the microleakage scores of Clearfil S3 Bond. When the control and surface-sealant groups were compared in the G-Aenial Bond enamel margins, the application of surface-sealant significantly reduced microleakage after 6 and 12 months. For Optibond AiO, no statistically significant differences in enamel and dentin margins were observed between the control and surface-sealant application groups.

Conclusion: The application of surface-sealant could be considered appropriate for reducing microleakage in composite resin restorations, but this effect might depend on the dentin adhesive.     

Effect of different dentin adhesives and application modes on sealing ability of amalgam restorations

Purpose: The aim of the study was to evaluate the sealing ability of bonded amalgam restorations using different adhesive materials with different adhesive application methods including amalgam bonding application. Materials and methods: The prepared Class-V cavities were randomly assigned to four application groups of four tested dual-curing dentin adhesives (Scotchbond Multi-Purpose Plus, XP Bond, Xeno IV and Clearfil Liner Bond 2V), dual-curing resin-based cement (Panavia F2.0) and a control group (unlined amalgam). Group 1 adhesives were applied according to the instructions for direct light-curing, Group 2 chemical-curing mode was applied according to the manufacturer’s amalgam bonding instructions. Group 3 adhesives were first applied in light-curing mode, and then amalgam bonding adhesive was applied. Group 4 adhesives were first applied in chemical-curing mode, followed immediately by light-curing mode. After that, amalgam adhesive parts were applied; then, the amalgam was condensed and carved. After storage for 24 h in distilled water at 37 °C, restorations were finished and polished. The teeth were then thermocycled (500 cycles between 5 and 55 °C), and the specimens were examined for microleakage using methylene blue as a marker. Results: Compared to the control group, the adhesive application modes significantly reduced microleakage for both dentin and enamel margins (p < 0.05). In dentin margins of the adhesives tested, Group 4 showed the lowest leakage score. On the enamel margins for Scotchbond Multi-Purpose Plus and XP Bond, Group 1 showed the highest microleakage (p < 0.05). Conclusion: According to marginal sealing ability and ease of application, Group 2 was recommended for the etch and rinse systems, and Group 4 was also recommended for the self-etch systems under amalgam restorations.     

Are antibacterial component additions in etchants and adhesives effective against Streptococcus Mutans?

The aim was to investigate the antibacterial activity of various acids and adhesives with and without antibacterial components against Streptococcus mutans. The antibacterial activities of 35% phosphoric acid (Ultra-Etch), 37% phosphoric acid with benzalkonium chloride (Etch-37), adhesive with chlorhexidine (Peak Universal Bond) and without any agent (PQ1) were investigated by agar-diffusion test. The inhibition-zones were measured after 48 h of incubation. For the tooth-cavity model test; cylindrical cavities were prepared on occlusal dentin surfaces of human molars and divided into four groups (n = 10 cavity/group). Group 1: Ultra-Etch + Peak Universal Bond, Group 2: Ultra-Etch + PQ1, Group 3: Etch-37 + PQ1 were applied. The fourth group without any agent application served as control. The teeth were immersed in 5.8 × 10⁶ cfu/ml of S. mutans solution to infect the cavities for 72 h before the application of the groups. After 72 h, dentin chips were collected from the cavity walls with burs for bacterial counting. Statistical analysis was performed by ANOVA, Bonferroni and Dunnett C tests (p < 0.05). Ultra-Etch and Etch-37 performed similar antibacterial activities in agar-diffusion test. Both acids showed better antibacterial activity compared to adhesives (p < 0.05). The antibacterial activity of PQ1 and Peak Universal Bond was observed to be inactivated by light-polymerization. According to the tooth-cavity model; Group I, II, and III demonstrated reduction in bacterial number and there was no significant difference between them. Antibacterial component additions in etchant and adhesive did not show superior antibacterial activity against S. mutans in both in vitro tests.     

Compressive strength and failure types of cusp replacing direct resin composite restorations in previously amalgam-filled premolars versus sound teeth

This study evaluated the fracture resistance of cusp replacing direct resin composite restorations (DCR) in premolars that had been previously filled with amalgam mesial–occlusal–distal (MOD) restorations and compared their fracture resistance with those made on sound dentin and intact teeth. Recently extracted human premolars with either MOD amalgam restorations or sound/intact ones were selected for the study. Cavities with cusp reduction were made for the following groups: (a) Group 1: DCRs on previously amalgam-affected dentin (n = 11), (b) Group 2: DCRs on sound dentin (n = 10), and (c) Group 3: intact premolars (n = 9). Teeth in Groups 1 and 2 were restored with a 3-step etch and rinse adhesive (Quadrant Unibond) and filled with hybrid composite (Clearfil Photo Posterior). All specimens were thermocycled for 5000 cycles (5–55 °C). The buccal cusps of the teeth were loaded until fracture under compression at 45° to the long axis of the teeth in a universal testing machine (1 mm/min). Data (N) were statistically analyzed using one-way ANOVA and Student’s t-test (α = 0.01). Intact teeth (Group 3) showed significantly higher fracture resistance (893 ± 196) compared to both restored groups (p < 0.01). No significant difference was found between the DCRs made on amalgam-affected dentin (Group 1: 607 ± 166) and sound dentin (Group 2: 588 ± 183) (p > 0.01). More than half of the teeth of Groups 2 and 3 showed unrepairable fractures with pulp exposure.     

The effect of Er:YAG laser and bulk filled composite type on marginal adaptation of class II cavities: an SEM analysis study

Purpose: To evaluate the effect of cavity preparation method (Er:YAG laser or diamond bur) and bulk-filled composite material type on marginal adaptation mesial occlusal (MO) class II cavities. Materials and Methods: Two-surface box cavities (4-mm proximal depth and 5-mm occlusal width) were prepared on 60 human mandibular molar teeth. Cavities were prepared using Er:YAG laser or diamond burs in an air-turbine hand-piece. All cavities were applied Single Bond Universal dentin bonding agent. The cavities were further subdivided into three subgroups according to the restorative material used; two bulk-filled composites [Filtek Bulk Fill Posterior (3M ESPE) and SonicFill 2 (Kerr)] and one traditional composite material Filtek Ultimate Universal Restorative (3M ESPE). Restorations were evaluated using scanning electron microscopy at ×200 magnification for their adaptation to the approximal margins of the tooth. Results were analyzed using the two-way ANOVA and Tukey Post Hoc Test (p < 0.05). Results: A total of 900 SEM figures were obtained from all groups. Filtek Bulk Fill Posterior, SonicFill 2, and Filtek Ultimate Universal Restorative exhibited statistically similar gapped margins. However, the lowest scores of gapped margins were observed with SonicFill 2 (4.22%). Conclusions: Completely gap-free margins were not obtained with any of the tested materials. Bulk-fill composite materials showed similar marginal adapatation compared with standard composite. Marginal adaptation of Er:YAG laser prepared cavities was more irregular and had more gaps, but was statistically similar to diamond bur-prepared cavities.     

Effect of material and fabrication technique on marginal fit and fracture resistance of adhesively luted inlays made of CAD/CAM ceramics and hybrid materials

This study evaluated the fracture resistance and marginal fit of CAD/CAM ceramic and composite inlays. Molars (N = 80) were prepared to receive Mesio-occlusal-distal (MOD) inlays and randomly divided into four groups to be restored depending on the materials: (a) HLD: heat-pressed lithium disilicate ceramic (IPS e.max Press), (b) CLD: CAD/CAM-fabricated lithium disilicate ceramic (IPS e.max CAD), (c) NC: CAD/CAM nano-ceramic resin (Lava Ultimate), (d) RC: Indirect resin composite (Filtek P60). Each group was randomly divided into two subgroups regarding the resin cement: (a) High-viscosity resin cement (Syntac, Variolink II), (b) Self-adhesive low-viscosity cement (RelyX Ultimate). After marginal gap and cement thickness measurements, specimens were loaded to fracture in a Universal Testing Machine (1 mm/min). Intact molars acted as the control group (n = 10). Data were analyzed using one-way and two-way ANOVA, Tukey’s tests (α = 0.05). Before cementation, CLD group showed significantly lower mean marginal gap (65 ± 22.4 μm) and after cementation, cement thickness was again the lowest with CLD (82.6 ± 24.6 μm) and the highest with HLD (108.4 ± 21.3 μm) (p < 0.001). The mean marginal gaps of inlays at the gingival margin were significantly higher than at the occlusal and the axial margins (p < 0.05). While material type significantly affected the mean fracture resistance (p < 0.001), the cement type had no effect on the results (p = 0.083). NC group (2486 ± 40 N) showed significantly higher mean fracture load compared to those of other three groups (1997.5 ± 60–2007 ± 30) (p < 0.05). The mean fracture resistance of control group with the intact teeth was significantly higher than those of all groups (p < 0.05) except for NC (p > 0.05).     

Load-bearing capacity and failure types of premolars restored with sonic activated bulk-fill-, nano-hybrid and silorane-based resin restorative materials

This study evaluated the load-bearing capacity of premolars restored with three types of resin composite materials in mesio-occluso-distal (MOD) cavities. Extracted human premolars (N = 30, n = 10 per group) were randomly divided into three groups; MOD cavities were prepared and restored with one of the following resin materials: Group BFC: Bulk-fill composite (SonicFill, Kerr Corporation), Group NC: Nanohybrid resin composite (Filtek Z550, 3M ESPE), Group SC: Silorane-based composite (Filtek Silorane, 3M ESPE). For NC Clearfil SE Bond (Kuraray, Japan) and for SC, Silorane adhesive resin (Filtek Silorane System Adhesive, 3M ESPE) were used. The cavities in NC and SC groups were restored incrementally, while those in BFC groups were restored in bulk. After water storage (24 h, 37 °C), each tooth was subjected to compressive loading with a stainless steel ball (diameter: 4 mm) perpendicular to the occlusal surface (1 mm/min). Failure types were categorized according to being repairable or irrepairable. Data were statistically analysed using Kruskal-Wallis test (α = 0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale (m) and shape (0) values were calculated. Fracture resistance of premolars restored with BFC (829.84), NC (701.35) and SC (807.73) did not show significant difference (p = 0.72). Weibull distribution presented lower shape (0) for SC (m = 2.77) and NC (m = 3.09) compared to BFC (m = 5.01). The incidence of repairable failures was more common in BFC (80%) compared to NC (60%) and SC (50%). Adhesive failures were more often observed in NC (80%) and SC (70%) groups.     

Fracture strength of composite resins for endodontically treated molars

Objectives: The purpose of this study was to evaluate the effect of different fabrication techniques on the fracture strength of the composite resin-based inlay restorations of endodontically treated molars. Methods: Sixty mandibular molars were divided into six groups (n = 10) designated according to the treatment as: Group-1: Control group, intact teeth; Group-2: Filtek Ultimate Universal restorative with incremental technique; Group-3: Filtek Bulk Fill Posterior restorative; Group-4: Biodentine with Filtek Ultimate Universal restorative; Group 5: everX Posterior with Filtek Ultimate Universal restorative; and Group-6: Lava Ultimate CAD/CAM restorative. The standard mesio-occluso-distal cavities were prepared and the roots filled for all the teeth, except those of the control group. Following the placement of the restorations, the fracture resistance of the specimens was measured. The data were analyzed by the one-way analysis of variance and Tukey’s post hoc test. Results: While Group-1 (2815.80 N) exhibited significantly higher fracture strength than the other groups (p < 0.05), Groups-2 (2062.20 N), 3 (2166.00 N), 5 (2355.60 N), and 6 (2340.70 N) exhibited statistically similar results (p > 0.05). The Biodentine group (1480.50 N) exhibited significantly lower fracture strength than the rest of the groups (p < 0.05). Conclusions: The CAD/CAM and manual build-up techniques exhibited statistically similar results with the exception of Biodentine, which exhibited a significantly lower in vitro performance compared to the other composites used in the study. The fiber-supported composite everX Posterior increased the fracture strength of the endodontically treated teeth.     

Effects of cavity disinfectants on bond strength of an etch-and-rinse adhesive to water- or ethanol-saturated sound and caries-affected dentin

Objective: To evaluate the effect of cavity disinfectants on the immediate microtensile bond strength (μTBS) of an etch-and-rinse adhesive to water- and ethanol-saturated sound and caries-affected dentin (CAD). Material and Methods: Thirty-six human molars were sectioned to expose 1/3 of the mid-coronal dentin surface. Sound (n = 18) and CAD (n = 18) specimens were divided into six groups each (n = 3): one positive control (sound), one negative control (CAD), and five experimental groups each. In the control group, dentin surfaces were bonded using an etch-and-rinse adhesive with a traditional water-wet bonding technique. In the experimental groups, ozone was applied before etching and chlorhexidine after etching. In the ethanol-wet bonding groups, acid-etched dentin surfaces were treated with ethanol. Following adhesive application and composite buildups, bonded specimens were sectioned to form sticks. Failure modes were analyzed using a stereomicroscope. Results: The water-wet bonded sound control group yielded the highest μTBS among all groups (p < 0.001). The lowest μTBS values were observed in the ozone groups (p < 0.05). The ethanol-wet bonded CAD group exhibited a higher μTBS than the water-wet bonded negative controls. Although compared to the positive control, chlorhexidine decreased the μTBS (p < 0.05), an increase with no significant difference was observed in the negative control (p > 0.05). Conclusions: The μTBS values of CAD were lower than those of sound dentin. Ethanol-wet bonding improved the μTBS of CAD. Ozone application reduced the μTBS in both sound and CAD; chlorhexidine improved the immediate μTBS after etching in CAD.     

The effect of intracanal placement of various medicaments on the bond strength of three calcium silicate-based cements to root canal dentin

This study aimed to evaluate the effect of intracanal placement of various medicaments on the bond strength of ProRooT MTA, Biodentine, and Endosequence root repair material (ERRM) putty. Ninety extracted human mandibular premolar teeth were decoronated and instrumented using Protaper Next rotary system and #1 to #6 Peeso reamers. The prepared teeth were randomly divided into six groups according to the intracanal medicaments: Group 1: double antibiotic paste (DAP) consisting of metronidazole and ciprofloxacin; Group 2: Triple antibiotic paste (TAP) with cefaclor; Group 3: TAPwith clindamycin; Group 4: amoxicillin and clavulanic acid (Augmentin®); Group 5: calcium hydroxide (CH); Group 6: control (no medicament) (n = 15). Parallel transverse sections were obtained in the coronal to the apical direction (4 slices/ tooth) and were divided into three subgroups according to the cements: Group A: ProRoot MTA; Group B: Biodentine; Group C: ERRM (n = 20 slices/subgroup). A push-out test was used to measure bond strength. Data were analyzed using two-way analysis of variance and Tukey’s post hoc test. The bond strength was significantly lower for DAP and TAPs than for Augmentin®, CH, or the control (p < 0.05). Biodentine and ERRM had significantly higher bond strength values than ProRooT MTA (p < 0.05) regardless of the intracanal medicaments tested, while no significant difference existed between Biodentine and ERRM (p > 0.05). While the application of DAP or TAPs decreased the bond strength, application of CH or Augmentin® did not. ERRM and Biodentine had higher bond strength values than ProRoot MTA.