Is use of flowable resin composite an option for occluso-proximal restorations in primary teeth? A fracture strength analysis

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 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 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.