Background: The purpose of this study was to clinically examine the efficacy of tunnel preparations in primary molars restored with glass-ionomer cement during a 36-month observation period.
Methods: A total of 233 tunnel restorations were placed in primary molars of 203 patients aged 6-10 years. Restorations were evaluated after 12, 24 and 36 months using the modified USPHS criteria for secondary caries, marginal discolouration, marginal adaptation and anatomic form. The Alpha+Bravo score (except for caries) and absence of clinical signs of endodontic complications was considered as a clinical success.
Results: At the end of the 36-month experimental period, the cumulative survival rate of tunnel restorations in primary molars was 72 per cent. The main reasons for failure were endodontic complications (46 per cent of the failures), secondary caries (31 per cent of the failures) and marginal ridge fractures (19 per cent of the failures).
Conclusions: The tunnel preparation filled with reinforced restorative glass-ionomer cement is a suitable treatment for minimal proximal caries lesions in primary molars.