RESUMEN
BACKGROUND: Use of flowable resin composites for ocluso-proximal restorations in primary molars could improve cervical adaptation, and reduce the failure risk. AIM: To investigate the fracture strength of occluso-proximal restorations in primary teeth using different flowable resin composites (as an intermediate layer or entire cavity) and a conventional resin composite (incremental technique). DESIGN: Two standardized occluso-proximal cavities were prepared on mesial and distal surfaces of 50 sound primary molars. The teeth were randomly assigned into five groups (n = 10): 2 mm Filtek Bulk Fill Flow + Z350 XT; 4 mm Filtek Bulk Fill Flow; 2 mm Z350 XT Flow + Z350 XT; 4 mm Z350 XT Flow; and Z350 XT inserted by incremental technique. All restored teeth were subjected to cariogenic challenge and then submitted to fracture strength test. The failure pattern of each specimen was categorized as reparable or irreparable/need for replacement based on the World Dental Federation (FDI) criteria. Fracture strength means were submitted to one-way ANOVA and Tukey's post hoc tests. Failure pattern was analyzed descriptively. RESULTS: There was no statistically significant difference on fracture strength among groups (p = .48). A similar distribution of reparable (35%-40%) and irreparable (60%-65%) failures was observed among groups. CONCLUSION: Based on a laboratorial setting, the use of different flowable resin composites (as an intermediate layer or entire cavity) may be an option to restore occluso-proximal cavities in primary molars.
RESUMEN
Purpose: To systematically review the literature to compare the bond strength of universal adhesives with etch-and-rinse and self-etch systems to primary teeth. Methods: The search was carried out in PubMed® /MEDLINE, Scopus® , LILACS, Embase® , and Web of Science™ databases with no restrictions. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. Direct comparisons among universal adhesive in etch-and-rinse (UER) and self-etch (USE) modes and etch-and-rinse (ER) and self-etch (SE) systems were performed considering different substrates (sound enamel and dentin, and carious dentin) through meta-analyses of random effects. A mixed treatment comparisons meta-analysis was also performed comparing the bond strength of all adhesive approaches on sound dentin. Results: From 3,276 potentially eligible studies, 18 were selected for full-text analysis, and eight were included in the systematic review. All studies included in the meta-analyses evaluated a mild universal adhesive (Scotchbond™ Universal). In direct comparisons, there was no difference between USE and SE to sound enamel (mean difference [MD] equals 5.22; 95 percent confidence interval [95% CI] equals -9.09 to 19.52). In carious dentin, the results favored only ER over USE (MD equals -3.88; 95% CI equals -7.40 to -0.37). In sound dentin, the bond strength values of UER were higher than ER (MD equals 5.50; 95% CI equals 4.03 to 6.96). The rank probability showed that the best treatment on sound dentin was UER. Conclusion: Pooled in vitro data suggest that a mild universal adhesive system can substitute the etch-and-rinse and self-etch systems for restoring primary teeth.