Silorane-based Composite Restorations Research Articles

INFLUENCE OF DIFFERENT CAVITY DISINFECTION SOLUTIONS AND LASER SYSTEMS ON REPAIR BOND STRENGTH OF SILORANE BASED COMPOSITE

Purpose: Evaluating effects of Nd:YAG-laser, Er:YAG-laser, chlorhexidine and ozonated water application which is used for purpose of antibacterial effects, on repair bond strength of silorane based composite. Materials and Methods: 100 cavities (2 mm deep, 3 mm diameter) prepared in acrylic blocks were filled with silorane composite and subjected thermal cycle and divided into 5 groups (N=20). Group 1:Chlorhexidine; Group 2:Ozonated-water; Group 3:Nd:YAG-laser; Group 4:Er:YAG-laser; Group 5 (control): untreated. Composite repair procedure was implemented with the same silorane based composite. Groups divided into 2 subgroups (n=10). One of the subgroups for each group was subjected second thermal cycle. All of the samples tested by a universal test device. Data were analyzed statistically and significance test of the difference between the two means (Kolmogorov-Simirnov), the variance analysis, and Student-t Test used. Results: No statistical difference was observed among groups after first thermal cycle (p>0,05). After the composite repair, there were no statistically significant difference between groups that were subjected to second thermal cycle (p>0,05). When each group was evaluated in themselves on comparing before and after the thermal cycle after the repair operation; as no statistically significant difference between Ozonated-water, Nd:YAG, Er:YAG and Control groups (p>0,05), a statistically significant decrease was observed only in the Chlorhexidine group after thermal cycle (p<0.05). Conclusion: Ozonated-water, Nd:YAG-laser and Er:YAG-laser applications can be used in the repair of silorane-based composite restorations as an alternative antibacterial application, since the application of chlorhexidine reduces the repair bonding strength.

Evaluation of Microhardness and Microleakage of Class II Silorane-Based Composite Restorations Post-Photoactivation Silorane-Based Composite Restorations Post-Photoactivation Techniques Technique

Objectives: The purpose of this study was to evaluate effect of additional light curing on microhardness and microleakage at cervical third of class II silorane-based composite restorations. Methods: Class II cavities were prepared on the proximal surfaces of 20 human premolars. The specimens were randomly divided into two groups of 10. In both groups, class II cavities were restored incrementally (gingival, oblique buccal and oblique lingual) with silorane-based composite (Filtek P90) and cured (group1: occlusal curing; group 2: additional curing from buccal and lingual). The samples were immersed in 0.5% fuchsine and dye penetration was recorded at the four regions of the gingival floor. Also, Vickers hardness test was performed at a distance of 1 mm above the gingival margin. Data were statistically analyzed using ANOVA after the evaluation of normal data distribution with Kolmogorov–Smirnov test at the 0.05 level of significance. Results: The two photo activation methods significantly affected the hardness (p=0.005) and microleakage (p=0.045). Additional light curing increased Vickers hardness when compared to occlusal curing. Comparison of microleakage in different areas of the first group did not show any significant difference (p=0.240) but the differences were significant between the different areas of the second group (p=0.028). Additional light curing decreased dye penetration in the all depths. Only in the H3 and M3, curing technique showed a significant effect on the results. Conclusions: Additional light curing would cause in better hardness and less microleakage. Therefore it is suggested after initial occlusal curing.

Influence of surface treatment on the performance of silorane-based composite resin in class I restorations: a randomized clinical trial.

The aim of this study was to evaluate the clinical performance of silorane-based composite restorations applied after different surface treatments. This controlled and randomized clinical trial included 26 patients with class I restoration indications. The teeth were randomly assigned to the following treatments: control 1/G1, silorane specific self-etching adhesive (P90 self-etch primer and bond) + silorane-based composite resin (Filtek™ P90 low shrink posterior restorative); G2, 37% phosphoric acid + silorane specific self-etching adhesive + silorane-based composite resin; G3, blasting with aluminum oxide + silorane specific self-etching adhesive + silorane-based composite resin; and control 2/G4, self-etching adhesive (Adper™ SE Plus self-etch adhesive) + dimethacrylate-based composite resin (Filtek™ P60 posterior restorative). The clinical performance was evaluated at baseline and after 1year. A total of 141 restorations were made and evaluated. For all clinical criteria evaluated, no significant difference was found between the surface treatments at baseline and after 1year (p > 0.05). After 1year, only the group with 37% phosphoric acid + silorane specific self-etching adhesive (G2) showed a significant reduction in marginal adaptation (p < 0.05). In general, all surface treatments showed an adequate clinical performance for silorane-based composite resin in class I restorations. However, a reduction in the marginal adaptation after 1year was found when additional phosphoric acid etching was used prior to silorane specific self-etching adhesive. The use of phosphoric acid etching prior to specific self-etching adhesive can adversely affect the marginal adaptation of silorane-based restorations.

Role of TiF4 in Microleakage of Silorane and Methacrylate-based Composite Resins in Class V Cavities.

This study investigated the effect of TiF4 solution pretreat-ment on microleakage of silorane and nanofilled methacrylate-based composites in class V cavities. Forty-eight intact premolar teeth were randomly allocated to four groups of 12 teeth. Restorative techniques after standard class V tooth preparations were as follows: Group 1, Filtek P90 composite; group 2, Filtek Z350 XT; group 3, TiF4 solution pretreatment and Filtek P90 composite; group 4, TiF4 solution pretreatment and Filtek Z350 XT. After storing the specimens in distilled water at 37°C for 24 hours and followed by immersion of the specimens in a 0.5% basic-fuchsin solution for 24 hours, they were sectioned buccolingually to obtain four surfaces for each specimen for analysis of microleakage using a stereomicroscope. Data analysis was performed using Kruskal-Wallis test to compare the four groups and the Mann-Whitney test for paired comparisons with Statistical Package for the Social Sciences (SPSS) version 17 software. At the enamel margins, microleakage score of the Filtek Z350 XT group was lower than those of the Filtek P90 with and without the application of the TiF4 (p = 0.009 and p = 0.031 respectively). At the dentin margins, groups 3 and 4 (TiF4+Filtek P90 and TiF4+Filtek z350 XT respectively) showed significantly lower microleakage than group 1 (Filtek P90). However, there was no significant difference between other groups (p > 0.05). At the enamel margins, microleakage score of the silorane-based composite was more than that of the nanofilled composite. No significant differences were observed between the other groups. At the dentin margins, for the silorane-based composite restorations, TiF4 solution pretreatment resulted in significantly lower microleakage. However, the similar result was not observed for Filtek Z350 XT. Also, no significant difference was observed between microleakage scores of Filtek P90 and Filtek Z350 XT with or without TiF4 pretreatment. In spite of better mechanical and physical properties of modern composites than earlier methacrylate-based composites, polymerization shrinkage has been remaining as one of the main shortcomings of them. Different methods, such as using new low shrinkage resin composites and different dentin pretreatments, have been suggested to overcome this problem. This study evaluated the effect of TiF4 as pretreatment on microleakage of class V tooth preparations restored with a nanocomposite and a silorane-based resin composite.

Two-year clinical performance of dimethacrylatebased composite restorations repaired with a silorane-based composite.

To investigate the clinical performance of a silorane-based composite resin used for repairing dimethacrylate- based composite restorations. One operator repaired defective dimethacrylate-based resin restorations that were randomly assigned to one of two treatment groups: control (n=50), repaired with Adper SE Plus and Filtek P60 Posterior Restorative (3M ESPE); or test (n=50), repaired with P90 System Adhesive Self-Etch Primer and Bond and Filtek P90 Low Shrink Posterior Restorative (3M ESPE). After 1 week, restorations were finished and polished. Two calibrated examiners (weighted Kappa≥0.78) evaluated the repaired restorations, blindly and independently, at baseline, after 6 months, 1 and 2 years. The parameters examined were marginal adaptation, anatomic form, surface roughness, marginal discoloration, postoperative sensitivity, and secondary caries. The restorations were classified as Alfa, Bravo, or Charlie, according to modified US Public Health Service criteria. Variation in the levels of clinical parameters over time was evaluated by Friedman's ANOVA (α=0.05). The Mann-Whitney test assessed the differences between the materials for all clinical criteria at baseline, 6-month, 1- and 2-year recalls (α=0.05). The Wilcoxon test compared each composite resin for all clinical criteria at the same recalls (α=0.05). After two years, 79 repaired restorations were re-examined. No statistically significant differences were found between the materials at baseline or at the 2-year recall (p>0.05). Comparing baseline and 2-year recall, there was a statistically significant difference for marginal discoloration (p=0.029) in silorane-based composite restorations. After two years, the clinical performance of the silorane-based composite was similar to that of the dimethacrylate-based composite when used to make repairs.

Effectiveness of Silorane-based Composite as a Repair Filling for Dimethacrylate- or Silorane-based Composite Restorations

ABSTRACT Objective This study aimed to evaluate the suitability of one specific silorane-based composite for the application as a repair material for different substrates. Materials and methods Truncated cones of composites fabricated and thermocycled for 6000 cycles to serve as a substrate were made of two commercially available dimethacrylate-based composites (DBC) (Filtek Supreme and Clearfil APX) and one silorane-based composite (SBC) (Filtek P90). The surface of the specimens was treated with air-abraded using Al2O3-particles of 50 µm size. A Teflon device was used to fabricate inverted truncated cones of repair composite over the surface-treated top of each original truncated cone. DBC and SBC were used as repair materials and bonded to the specimens using either a dimethacrylate-based (single bond 2) or a phosphate-methacrylate-based (adhesive belongs to the silorane) adhesives. The specimens were stored in distilled water at 37°C for 7 days and stressed to failure under tension. The data were analyzed with one-way ANOVA and Tukey tests at 5%. Results Bonding DBC as a repair material to a DBC substrate using the dimethacrylate-based adhesive produced the highest bond strength. Bonding DBC as repair material using the phosphate-methacrylate-based adhesive or SBC as repair material using the dimethacrylate-based adhesive produced lower bond strength, regardless the brand and of the chemical formulation of the aged substrate. Conclusion In order to obtain high bond strength, there is need to match adhesive and repair material, regardless the brand and of the chemical formulation of the substrate. How to cite this article Barcellos DC, Pleffken PR, Pucci CR, Pagani C, Gonçalves SEP, Torres CRG. Effectiveness of Silorane-based Composite as a Repair Filling for Dimethacrylate- or Silorane-based Composite Restorations. World J Dent 2012;3(2):161-65.

Effect of thermo-mechanical load cycling on silorane-based composite restorations

The aim of this study was to compare the formation of marginal gaps after thermo-mechanical load cycling, between siloranebased and methacrylate-based restorations. Standardized class II cavities were made in 10 permanent human third molars that were restored with the adhesive system Clearfil SE Bond+composite Filtek Z-350 (Methacrylates) and with the composite bonding Filtek P90+P90 (Siloranes), respectively. After 24 h of storage in 100% humidity at 37°C, the restoration margins were stained, photographed, and evaluated. The gap length was calculated as the percentage of the total length of the margins. Thereafter, the specimens were tested by a thermo-mechanical machine and the marginal gap formation of the specimens was re-evaluated. The results were expressed as percentages of gaps and were submitted to a Mann Whitney test at 5% level of significance. Methacrylates showed a statistically significant higher percentage of gaps than Siloranes, both before and after cycling.

Methacrylate- and silorane-based composite restorations: Hardness, depth of cure and interfacial gap formation as a function of the energy dose

Objectives To investigate the influence of the energy dose on the hardness, polymerization depth, and internal adaptation of silorane and methacrylate-based posterior composites in Class II restorations with different bonding approaches. Materials and methods Class II preparations were made on the mesial and distal surfaces of extracted third molars and randomly distributed into 6 groups ( n = 20), according to the restorative systems [methacrylate-based composite: Filtek P60 + Adper Single Bond 2 (etch-and-rinse adhesive) – P60/SB; Filtek P60 + Adper Easy One (self-etching adhesive) – P60/EO; silorane-based composite: Filtek P90 + P90 System Adhesive – P90 (self-etching adhesive)] and the energy dose (20 and 40 J/cm 2). Resin composites were applied in two increments, individually photoactivated using an LED light-curing unit. After 24 h, all restorations were mesio-distally sectioned. Hardness was evaluated along the transversal section of the fillings (1–4 mm below the restoration surface) using a load of 50 g for 5 s. In order to evaluate the internal gap formation, specimens were air dried and 1% acid red propylene glycol solution was applied to the internal margins for 20 s. Specimens were then water rinsed, air dried, and digitally image recorded. The internal gap (%) was calculated as the ratio between the stained margins and the total length of the internal margin. Kruskal–Wallis test was conducted to evaluate internal gap formation, and three-way ANOVA and Tukey's test were performed to evaluate hardness/polymerization depth ( α = 0.05). Results Regarding the internal gap formation, a significant difference was observed among all groups (P60/EO < P90 < P60/SB), regardless of the energy dose. For 40 J/cm 2, a significant increase in gap formation was seen for P60/EO and P90 when compared to 20 J/cm 2. The KHN of both resin composites was not affected by the depth of evaluation, but the influence of the material was significant (P60 > P90; p < 0.05). The highest energy dose (40 J/cm 2) produced significant increase in the KHN only for Filtek P90 ( p < 0.05). Significance Although a higher energy dose produces a slight increase in hardness for the silorane based composite, it also increases the internal gap formation. Dose of 20 J/cm 2 seems to be more suitable as it provides reduced internal gaps and satisfactory hardness. In addition, gap formation seems to be a consequence of an underperformed bonding approach rather than the differences in the resin-composite formulation.

Utilization of Occlusal Index and Layering Technique in Class I Silorane-based Composite Restorations

PURPOSE This article describes a technique that uses an occlusal index to restore teeth back to their original contour and anatomy with minimal finishing. A new type of ring-opening silorane composite reported to have less than 1% volumetric shrinkage was used in the restoration. For the silorane-based composite, there is no oxygen-inhibited layer to be polished away. The final composite layer is cured under pressure and further minimizes voids and gap formation. The technique can also be used on multiple posterior restorations under rubber dam isolation. Overall, if used properly, this technique helps the clinician produce superb anatomy and reduces time for posterior composite restorations.