Effects of glass lonomer and microfilled composite subgingival restorations on periodontal tissue and subgingival biofilm: A 6-month evaluation

Background: This 6-month study evaluated the effects of resin-modified glass-ionomer cement (RMGI) and microfilled composite (MC) subgingival restorations on periodontal tissues and subgingival biofilm. Methods: Fifty-four periodontally healthy patients were assigned as follows: group I (N = 18), root exposure (RE) without non-carious cervical lesions (NCCL) treated with coronally positioned flap (CPF); group 2 (N = 18), RE with NCCL treated RMGI restorations plus CPF; group 3 (N = 18), RE with NCCL treated with MC restorations plus CPF. Probing depth (PD), visible local plaque score (PL), and local bleeding on probing (BOP) were assessed at baseline and 6 months after surgeries. Restored and non-restored root recoverage (RR) was assessed at 6 months. Each experimental tooth was subgingivally sampled (baseline and 6 months) and analyzed by checkerboard DNA-DNA hybridization. Results: Clinical results showed no significant differences among the groups regarding PL, BOP, and PD at baseline and 6 months. The RR means were similar among the groups at 6 months. Intragroup analyses revealed that the proportions of 10 periodontopathogens decreased at 6 months for the control group. For the RMGI group, there was a significant decrease in the proportions of nine periodontopathogens. For the MC group, there was a significant increase in the proportions of Fusobacterium nucleatum polymorphum and Gemella morbillorum and a decrease in five periodontopathogens. Intergroup analyses showed an increase in the proportion of F. nucleatum polymorphum for the MC group. Conclusions: In a 6-month evaluation, well-finished RMGI or MC subgingival restorations did not negatively affect periodontal health. Furthermore, RMGI seems to exert more positive effects on the subgingival biofilm composition than MC.