Introduction
Direct restorations, in common with all other forms of restorations, suffer deterioration as a result of “wear and tear”, and may be susceptible to secondary caries in clinical service. Defects in restorations and lesions of secondary caries adjacent to restoration margins are two of the most frequent clinical observations in general dental practice. Replacement of restorations constitutes around half of the treatments performed by general dental practitioners. However, total restoration replacement may be regarded as excessively interventional in many situations, since in the large majority of cases, most of the restoration (.80%) may be found to be clinically and radiographically sound. Furthermore, restoration replacement invariably results in acceleration of the “restoration death spiral” with weakening of the remaining tooth structure through the unnecessary removal of healthy tooth tissue in locations often distant from the site of the deteriorating restoration. An additional risk associated with restoration replacement is unnecessary and potentially fatal insult to the pulp. Consequently, good decision-making in respect of “defective” restorations is central to effective restorative treatment planning, particularly given the growing body of evidence confirming the value and importance of procedures to repair defective restorations.