Bond strength of a compomer to dentin under various surface conditions

Airborne-particle Abrasion and Dentin Bonding: Systematic Review and Meta-analysis

CLINICAL RELEVANCE

The literature reviewed suggests that airborne particle abrasion has no negative effects on the bond strength of resin-based materials to dentin and that a positive influence on dentin bond strength was only achieved in specific air-abrasion conditions.

SUMMARY

In this systematic review the authors investigated how airborne-particle abrasion (APA) using aluminum oxide affects the bond strength of resin-based materials to dentin. The search was performed in three databases. In vitro studies (Type of study) comparing the bond strength of resin-based materials (Outcome) to air-abraded (Intervention) compared with non-air-abraded (Comparison) human dentin (Population) were included (the PICOT elements are given parenthetically). From 5437 unique articles, 65 were read in full, 33 were included in the qualitative synthesis, and 32 were included in the meta-analysis. Methodologic quality and risk of bias were assessed. Comparisons were performed between air-abraded and control dentin groups by adopting a random-effects model (α=0.05). Additional analyses were carried out for the different parameters used in APA: type of surface treatment in the control group, particle size, air pressure, and APA duration. The bond strength to air-abraded dentin was favored only when the control surface was treated with a hand excavator. For particle size, APA was favored when the particle size was >30 μm and the controls were no treatment or hand excavator or when the particle size was ≤30 μm and the control was bur. In addition, the results favored air-abraded groups only when the pressure was > 5 bar and bur was used in the control group. No significant differences were observed for duration of APA. No comparison on bond strength considering the presence of aging conditions was possible in the included studies due to the low number of studies that aged the specimens. In conclusion, APA had no negative effects on the bond strength of resin-based materials to dentin and was able to improve the dentin bond strength only when the particle size was > 30 μm and air pressure was > 5 bar. PROSPERO registration protocol: CRD42018096128.

Effect of dentine conditioning on adhesion of resin-modified glass ionomer adhesives

BACKGROUND

The aim of this study was to investigate the use of phosphoric acid as a surface treatment compared to traditional conditioning agents to dentine bonded with resin-modified glass ionomer (RMGIC) adhesives.

METHODS

Forty human molars were utilized in microtensile bond strength testing, while another 16 were used for evaluation of the bonded interface with scanning electron microscopy. Three RMGIC adhesives were evaluated: Fuji Bond LC (GC Corp); Riva Bond LC (SDI Ltd); and Ketac N100 (3M-ESPE). Surface treatments were 37% phosphoric acid (5 s) or 25-30% polyacrylic acid (PAA) (10 s), or the manufacturer's method - Fuji Bond LC: Cavity Conditioner (20% PAA + 3% AlCl3 10 s) or Ketac N100 primer: Ketac Nano priming agent (15 s). Teeth were finished with 600-grit SiC paper, surfaces treated and bonded with RMGIC adhesive and stored in distilled water for 24 h then subjected to microtensile bond strength testing.

RESULTS

Two-way analysis of variance (ANOVA) revealed adhesion was affected by the 'type of RMGIC adhesive' and 'method of dentine surface treatment' (p < 0.05). The microtensile bond strength of Ketac N100 primer groups was lower than Fuji Bond LC and Riva Bond LC (p < 0.05).

CONCLUSIONS

For RMGIC adhesives a brief etch with phosphoric acid does not adversely effect short-term bond strengths, but is no better than traditional conditioning with PAA.

The effect of airborne-particle abrasion on the shear bond strength of four restorative materials to enamel and dentin

STATEMENT OF PROBLEM

The role of airborne-particle abrasion on the bond strength of restorative materials to enamel and dentin is controversial.

PURPOSE

The purpose of this study was to evaluate the effect of airborne-particle abrasion on the shear bond strengths of 4 restorative materials to enamel and dentin.

MATERIAL AND METHODS

One hundred twelve extracted human maxillary anterior teeth were divided into 2 groups of 56 teeth each. In the first group flat enamel surfaces were prepared, and in the second flat dentin surfaces were prepared. Half the teeth in each group (n=28) were airborne-particle abraded. The remaining 28 teeth in each group were prepared with silicone carbide paper (control). Specimens in both groups were divided into 4 subgroups (n=7). A composite, a compomer, a resin-modified glass ionomer cement, and a conventional glass ionomer cement were applied to enamel and dentin surfaces (3 mm diameter and 4 mm height). After 24 hours of storage in water, specimens were subjected to shear forces in a universal testing machine at a crosshead speed of 0.5 mm/min until fracture. Shear bond strength data (MPa) were analyzed with 3-way ANOVA and Tukey HSD tests (alpha=.05).

RESULTS

Airborne-particle-abraded specimens showed significantly higher shear bond strengths than control specimens. The 2-way interaction between tooth structure and restorative materials was significant.

CONCLUSION

The use of airborne-particle abrasion increased the shear bond strength of restorative materials tested to enamel and dentin.

Marginal quality and microleakage of adhesive class V restorations

OBJECTIVES

The aim of this in vitro study was to determine the marginal quality and microleakage of composite resin class V restorations.

METHODS

Standardized mixed class V cavities (diameter: 4mm, depth: 2mm) with half of the finish lines limited within dentin were cut in 90 freshly extracted human molars and randomly assigned to nine groups (n=10). After etching enamel and dentin, the cavities were restored with nine different restorative systems (Syntac Sprint/Tetric Ceram=SS, Syntac Single-Component/Tetric Ceram=SC, Onestep/Aeliteflo=OS, Aquaprep+Onestep/Aeliteflo=OA, Prime & Bond 2.1/TPH=PB, Optibond Solo/Prodigy=OP, Singlebond/Z100=SB, Tenure Quik/Marathon=TQ, Solobond M/Arabesk=SM) using a wet-bonding procedure. After finishing and polishing, the teeth were stored for 24h in distilled water at 37 degrees C before they were subjected to thermocycling (5/55 degrees C, 1000x). Epoxy replicas were made for margin analysis in the SEM. Specimens were stained in methylene blue, sectioned, and evaluated for microleakage. Dye penetration was scored on a 0-3 ordinal scale.

RESULTS

Statistical analysis (Kruskal-Wallis H-test, Mann-Whitney U-test) revealed significant differences (P<0.05) among the groups at dentin and enamel margins for the microleakage scores as well as for the results of the quantitative SEM margin analysis. SC revealed a significantly higher percentage of perfect margins in the SEM than OS and SM in enamel and dentin, respectively. OA exhibited significantly more leakage in enamel than all other groups.

CONCLUSIONS

None of the tested restorative systems achieved a perfect seal in dentin and enamel of mixed class V cavities. Marginal quality and sealing ability of adhesive systems to dentin, using a wet-bonding procedure, is still inferior compared with enamel margins.

Three-year clinical evaluation of direct and indirect composite restorations in posterior teeth

STATEMENT OF THE PROBLEM

Objective long-term clinical data are necessary to assess the performance of modern posterior composites as direct and indirect restorations.

PURPOSE

This prospective, long-term clinical trial evaluated direct and indirect composite restorations for clinical acceptability as posterior restoratives in single or multisurface cavities and provided a survey on the 3-year results.

MATERIAL AND METHODS

Under the supervision of an experienced dentist, 9 dental students placed 88 composite restorations (Tetric, blend-a-lux, Pertac-Hybrid Unifil), 43 direct composite restorations, and 45 indirect inlays. Clinical evaluation was performed at baseline and in yearly intervals after placement by 2 other experienced dentists, using modified USPHS criteria. A third follow-up of 60 restorations took place within 33 to 36 months after placement.

RESULTS

A total of 93% of indirect and 87% of direct restorations were assessed to be clinically excellent or acceptable. During the third year, 1 direct restoration in a molar failed because of margin opening. Indirect inlays exhibited a significantly better anatomic form of the surface than direct composite restorations. Premolars revealed a significantly better marginal integrity and anatomic form of the surface than molars. Restorations in molars exhibited a significantly higher failure rate compared with premolars.

CONCLUSION

Posterior composite restorations provided a satisfactory clinical performance over a 3-year period, even if placed by relatively inexperienced but supervised students.