No difference in the long-term clinical performance of direct and indirect inlay/onlay composite restorations in posterior teeth.

Data sourcesMedline, Embase, the Cochrane Oral Health Group's Trials Register and CENTRAL. Unpublished literature was searched on ClinicalTrials.gov, the National Research Register, and Pro-Quest Dissertation Abstracts and Thesis database. Hand searching of reference lists only.Study selectionRandomised controlled trials with a minimum of three years follow-up that compared direct to indirect inlays or onlays in posterior teeth. Primary outcome was failure (the need to replace or repair).Data extraction and synthesisTwo reviewers independently and in duplicate performed the study selection and two extracted data independently using a customised data extraction form. The unit of analysis was the restored tooth. Risk of bias was assessed using the Cochrane Risk of Bias tool. Meta-analysis was conducted on two studies using the random-effects model.ResultsThree studies were included. Across these studies there were 239 participants in whom 424 restorations were placed. Two studies compared direct and indirect inlays and had follow-up of five and 11 years respectively. One study compared direct and indirect onlays with a follow-up of five years. The studies were at unclear or high risk of bias. For direct and indirect inlays, Relative Risk (RR) of failure after five years was 1.54 (95% Cl: 0.42, 5.58; p = 0.52) in one study and, in another was 0.95 (95% Cl: 0.34, 2.63; p = 0.92) over 11 years. For onlays there was also no statistically-significant difference in survival, though overall five-year survival was 87% (95% CI: 81-93%).ConclusionsThere is insufficient evidence to favour the direct or indirect technique for the restoration of posterior teeth with inlays and onlays.