Do composite restorations in primary molar teeth have a higher survival rate following total or selective caries removal?

Abstract

Study design A double-blind randomised clinical trial, conducted between June 2009 and June 2011, in a paediatric dental department in a Brazilian dental school.Study selection Children aged 3-8 years, in good general health, with deep carious lesions (caries radiographically located in the inner quarter of dentine) affecting either one or two surfaces in primary molars were eligible for inclusion. Teeth were excluded if clinical or radiographic evidence of pulpal inflammation or necrosis or clinical mobility were observed. Pre-cooperative children were also excluded.Clinical procedures and success criteria Following a coin toss, 120 teeth were randomly assigned to two groups: 55 in the total caries removal (TCR) group and 65 in the selective caries removal (SCR) group. Procedures were carried out by three paediatric dentists under local anaesthesia and restored, using a layering technique, with composite under rubber dam. Restorations were evaluated at 3, 6, 12, 18, 24 and 36 months, using the US Public Health Service (USPHS) scale, by a single-blinded and calibrated examiner. A Charlie or Delta score, on the USPHS scale, at the margins of the restorations was considered as restoration failure. Gingival bleeding score, type of cavity (one or two surfaces) and presence of caries (active or inactive) were recorded as secondary outcomes; however, presence alone did not constitute restoration failure.Results Average survival rate of restorations across all teeth was 68% after 36 months, with SCR statistically significantly lower at 57% compared to TCR at 81% (p = 0.004). Annual failure rates for SCR and TCR were 17.3% and 6.7%, respectively. Two-surface restorations had lower survival rates (58%) compared to single-surface restorations (87%) (p = 0.02). Type of cavity and gingival bleeding statistically influenced the chance of restoration failure at 36 months.Conclusions Composite restorations placed after SCR in primary molars were found to fail more often compared to those restored after TCR. Two-surface cavities and poor gingival health negatively impacted restoration success.