Effect of Microleakage in Composite Filling on the Health of Dental Pulp

Abstract

Introduction: Clinical consequences of microleakage are secondary caries, pulp inflammation, marginal discoloration, postoperative sensitivity, and the reduction of the longevity of filling. Dentists expect from modern technology a composite material with high aesthetic value, less polymerization shrinkage, perfect marginal integrity, and relevant physicomechanical properties. This review aimed to investigate the problem of microleakage in the composite filling, as well as the effect of microleakage on dental pulp.
Methods: An online search of relevant papers was conducted, which include PubMed indexed literature, was performed by combining the term "bulk fill" and “microleakage” using the AND operator, from time to time to the terms of class II, class III, and V to try to introduce the studies that referred to the design of the cavity. The search strategy, performed using the PubMed controlled vocabulary and free terms, was defined on the basis of the following elements of the PICO question: The eligibility criteria are: in vitro or in vivo studies, published in the last 20 years (given the date of introduction of the material on the market) and written in English. It was decided to include studies on human teeth and in vitro studies to have a standardization of the cavity, which would not be possible to obtain in an in vivo study. We included studies that explicitly described that a cavity margin of the preparation was in the root cement.
Results: In comparison to conventional composite, the enamel micro-leakage in flowable bulk-fill composite was found comparable to conventional at score 0, lower than conventional at score 1, higher than conventional in score 2, and equal at score 3. However, the dentine micro-leakage was higher than conventional at score 0, equal at score 1 and 3, lower than conventional at score 2. Regarding cavity preparation, using a less traumatic system such as laser system may be favorable in pediatric dentistry. Hence, lasers can ablate enamel and dentin more effectively due to the highly efficient absorption in both water and hydroxyapatite. Concerning the bond strength, In comparison to conventional composite, the bond strength in flowable bulk fill composite was found comparable at 2 mm and higher than conventional composite at 4 and 6 mm. In regards to paste-like bulk fill composite, there was no study found in the literature aimed to assess the bond strength to dentine, according to the search strategy used in this review.