Minimally invasive direct restorations: a practical guide

The primary objectives of minimum intervention dentistry (MID) are to prevent or arrest active disease using non-operative management techniques. However, patients commonly present with cavitated caries lesions or failed restorations that are in need of operative intervention. Although much of clinical practice is devoted to preventing and managing the effects of caries and subsequent failure of the tooth-restoration complex, the clinical survival of restorations is often poor and becomes significantly worse as they increase in size and complexity. Minimally invasive (MI) restorative techniques present a range of well-documented advantages over more tissue-destructive traditional restorations by minimising unnecessary tooth tissue loss, insult to the dentine-pulp complex and reducing the risk of iatrogenic damage to adjacent hard and soft tissues. They also maximise the strength of the residual tooth structure by use of optimal adhesive restorative materials designed to restore function and aesthetics with durable, long-lasting restorations that are easy for the patient to maintain. In contemporary oral healthcare practice, if patients are to give valid consent for operative interventions, minimally invasive options must be offered, and may be expected to be the first choice of fully informed patients. This paper describes concepts of MID and provides an update of the latest materials, equipment and clinical techniques that are available for the minimally invasive restoration of anterior and posterior teeth with direct restorations.

Longevity of Direct Restorations in Stress-Bearing Posterior Cavities: A Retrospective Study

The aims of this retrospective clinical study were to compare the longevities of direct posterior amalgam restorations (AMs) and resin composite restorations (RCs) that were subjected to occlusal stresses and to investigate variables predictive of their outcome. A total of 269 AMs and RCs filled in Class I and II cavities of posterior teeth were evaluated with Kaplan-Meier survival estimator and multivariate Cox proportional hazard model. Seventy-one retreated restorations were reviewed from dental records. The other 198 restorations still in use were evaluated according to modified US Public Health Service (USPHS) criteria by two investigators. The longevity of RCs was significantly lower than that of AMs (AM = 8.7 years and RC = 5.0 years, p<0.05), especially in molars. The prognostic variables, such as age, restorative material, tooth type, operator group, diagnosis, cavity classification, and gender, affected the longevity of the restorations (multivariate Cox regression analysis, p<0.05). However, among the restorations working in oral cavities, their clinical performance evaluated with modified USPHS criteria showed no statistical difference between both restoratives. In contrast to the short longevity of RCs relative to AMs, the clinical performance of RCs working in oral cavities was observed to be not different from that of AMs. This suggests that once a RC starts to fail, it happens in a rapid progression. As posterior esthetic restorations, RCs must be observed carefully with periodic follow-ups for early detection and timely repair of failures.