The evaluation of various restoration techniques on internal adaptation of composites in class v cavities

Evaluation of the bond strength of chlorhexidine incorporated into the adhesive system composition: A PRISMA guided meta-analysis

Background/purpose

Composite resin is currently the most widely used dental restoration material. Previous studies have demonstrated that the application of Chlorhexidine (CHX) on the dentin surface after acid etching can result in an improvement in the integrity and stability of tooth restoration through time. In order to better understand whether CHX can help improve the stability of the resin-dentin bond strength, in this study, a comprehensive review of the effect of adding CHX to the adhesive system on the stability of immediate and long-term resin-dentin bond strength was conducted.

Materials and methods

This article was written in accordance with the PRISMA Statement and is registered on the International Prospective Register of Systematic Reviews (registration number CRD42018084962). Six electronic databases including PubMed, Embase, Cochrane library, ISI Web of Science, ClinicalTrials.gov and China National Knowledge Infrastructure (CNKI) were searched up to October, 2018. Ten articles were selected from 340 possible eligible articles for meta-analysis, and 41 sets of data were analyzed in the meta-analysis.

Results

The results indicated that the use of 0.1% and 0.2% CHX does not adversely affect the immediate bond strength (p > 0.05), but both 0.1% and 0.2% CHX increased bond strength compared with the control group over 12 months (p < 0.05). However, this trend does not represent a longer period of aging.

Conclusion

In these in vitro clinical trials, CHX incorporated into the bonding systems maintained the stability of bond strength.

Effect of digluconate chlorhexidine on bond strength between dental adhesive systems and dentin: A systematic review

Aim:

This study aimed to systematically review the literature for the effect of digluconate chlorhexidine (CHX) on bond strength between dental adhesive systems and dentin of composite restorations.

Materials and Methods:

The electronic databases that were searched to identify manuscripts for inclusion were Medline via PubMed and Google search engine. The search strategies were computer search of the database and review of reference lists of the related articles. Search words/terms were as follows: (digluconate chlorhexidine*) AND (dentin* OR adhesive system* OR bond strength*).

Results:

Bond strength reduction after CHX treatments varied among the studies, ranging 0-84.9%. In most of the studies, pretreatment CHX exhibited lower bond strength reduction than the control experimental groups. Researchers who previously investigated the effect of CHX on the bond strength of dental adhesive systems on dentin have reported contrary results, which may be attributed to different experimental methods, different designs of the experiments, and different materials investigated.

Conclusions:

Further investigations, in particular clinical studies, would be necessary to clarify the effect of CHX on the longevity of dentin bonds.

Effect of preheating and shade on surface microhardness of silorane-based composites

AIM

The aim of the present study was to evaluate the effect of preheating and shade on the surface microhardness of silorane-based composites.

METHODS

Three shades of two different types of composites were evaluated: a silorane-based composite and a methacrylate-based composite. The composites were tested at 23°C, and after preheating at 55°C. Five specimens were prepared for each experimental group. The top surface of the specimens was irradiated for 20 s using an LED unit. Vickers microhardness test was used to evaluate both top and bottom surfaces of the specimens, followed by 24-h storage in the dark. Statistical analysis was performed using one-way anova and Tukey's post-hoc test at a level of significance of α = 0.05.

RESULTS

There was a significant rise in microhardness as the temperature increased from 23 to 55°C for both the top and bottom surfaces of the tested composites (P < 0.05). The C2 shade of both composites exhibited the lowest microhardness (P < 0.05), while the A2 and A3 shades did not show significant differences compared to each other (P > 0.05) Filtek Silorane presented significantly lower microhardness than Filtek Z250 (P < 0.05), regardless of the temperature, shade, or depth of measurement.

CONCLUSIONS

Preheating, shade, and composition of the tested composite resins affected their surface microhardness.

Effect of temperature, curing time, and filler composition on surface microhardness of composite resins

Aim:

The aim of this study was to evaluate the microhardness of two composite resins when subjected to three different temperatures and three different light-curing times.

Materials and Methods:

Two composites were used; Filtek Z250 and Grandio. Three different temperatures (23, 37, and 55^oC) were used, utilizing a composite warmer. The heated samples were immediately injected into cylindrical molds (6 mm × 2 mm) and the top surface of the specimens was polymerized for 10, 20, and 40 sec, using a Quartz-Tungsten-Halogen light-curing unit (QTH LCU). Vickers microhardness measurements were performed from both the top and bottom surface of the specimens, following dry storage for 24 hours in the dark. Statistical analysis were performed using one-way analysis of variance (ANOVA) and Tukey post-hoc test at a level of significance of a = 0.05.

Results:

The results indicated that there was an increase in microhardness as the temperature of the composite was increased for either the top or the bottom surface (P < 0.05). Furthermore, there was a general increase in microhardness for both composites as curing time increased (P < 0.05). The type of composites did not influence the surface microhardness (P > 0.05).

Conclusions:

Temperature of composites affects their surface microhardness. Also, light-curing time influence microhardness values of the composites tested.