Management of defective direct dental restorations
When it comes to defects in existing restorations, monitoring, refurbishment or repair should be the first consideration, argue Igor Blum and Nairn Wilson.
Direct dental restorations, in common with all restorations, suffer deterioration and degradation in clinical service. The presence of defective restorations and restorations with the clinical diagnosis of secondary caries caries are amongst the most frequent clinical observations in general dental practice. The replacement of restorations constitutes around half of the treatment performed by general dental practitioners (Mjör, Moorhead, Dahl, 2000; Mjör et al, 2002).
Total restoration replacement may, however, be regarded as excessively interventive in many situations, since in the majority of cases most of the restoration may be found to be clinically and radiographically sound (Gordan et al, 2003; Blum, 2008). Furthermore, restoration replacement invariably results in the acceleration of the ‘restoration cycle’ (Elderton, 1990), with weakening of the tooth, through the unnecessary removal of intact tooth structure in locations often distant from the site of restoration deterioration, and the potential for an unnecessary, potentially fatal, insult to the pulp.
Consequently, decision making in respect of ‘defective’ restorations is a critical step in treatment planning, especially given the growing body of evidence demonstrating the value and effectiveness of procedures to repair restorations that have suffered some form of typically limited deterioration in clinical service.
The diagnosis of secondary caries is inconsistent among dental practitioners and often is not based on objective criteria (Kay et al, 1988; Noar, Smith, 1990; Bader, Shugars, 1992; Frencken et al, 2012). When in doubt, most dentists adopt a ‘defensive dentistry’ approach by choosing replacement, as opposed to one of the range of minimal intervention options,including systematic monitoring.
Replacement decisions are especially common for defective restorations not placed by the evaluating dentist (Bader, Shugars, 1993), as demonstrated in analyses of the patterns of dental restoration provision within UK NHS dental services and large US studies (Burke, Lucarotti, 2009; Bogacki et al, 2002).
For example, Bogacki et al (2002) noted, within a cohort of more than 300,000 patients, that the probability of survival of both posterior amalgam and resin composite restorations was in excess of 90% over five years, but that this survival rate dropped to 60% (for both types of restoration) when patients changed dentist.
A more recent dental practice-based study, involving 197 clinicians in the USA and Scandinavian countries, and close to 10,000 restorations, indicated that when considering treatment options for restorations with localised defects, in more than 75% of cases, the dentists chose replacement rather than repair (Gordan et al, 2012). The same study confirmed that the dentists who did not place a restoration, which had developed a defect, were more likely to replace it than those who did.
The diagnosis of a defect in a restoration, and the subsequent decision making, tends to be based on visual and tactile examinations. However, the subsequent management plan for the restored tooth should be based on risk assessments of further caries, structural deterioration, catastrophic failure and loss of pulp vitality.
The recognition of one or more limited defects in a restoration does not necessarily mean that the restoration has suffered irreversible damage to the extent that it requires immediate replacement. Most defects in restorations, other than those caused by fracture, develop gradually over possibly extended periods of time (Gordan et al, 2012), providing the clinician with an opportunity to address the causation of the problem and undertake some form of minimal intervention treatment to correct the defect and thereby extend the life expectancy of the restoration.
Minimal intervention treatment may include repair of the defects, especially if the defects are localised and accessible, or simply refurbishment of the restoration, if the defects are superficial (Gordan, 2001; Blum, Jagger, Wilson, 2011).