Clinical Evaluation of Low-shrinkage Giomer Resin Composite Versus Resin-Modified Glass Ionomer in Treatment of Cervical Caries Lesions: A Randomized Clinical Trial

The development of cervical lesions in permanent dentition may be related to carious or non- carious origin. Class V caries lesions may occur due to different factors such as poor oral hygiene, dietary habits, or xerostomia.

Management of cervical lesions presents serious problems with any restorative material. The two most common reasons for restoration failure are secondary caries at the tooth-restoration interface and loss of retention. Class V lesions often exhibit a low retentive cavity configuration (C-factor); which is responsible for marginal gaps around the restorations. Cervical margins -lying in either dentin or cementum- show unfavorable bonding performance, besides being usually subgingival where moisture control is difficult. The subgingival margin is not clinically desirable due to difficulty in cleaning and increased biofilm accumulation. Therefore, the selection of the restorative material can be challenging.

In this context, fluoride containing adhesive materials are considered ideal in restoring class V carious lesions. Resin modified glass ionomers (RMGI) are highly recommended in the restoration of cervical lesions. The most important advantages of glass ionomer are its chemical adhesion to the tooth structure, and its fluoride release. However, RMGI has lower weakness and esthetic properties compared to resin composite.

In our study, the comparator material will be light cured resin reinforced glass ionomer restorative. RMGI is recommended to restore carious cervical lesions; especially with its ability to inhibit secondary caries due to its fluoride releasing ability. The main advantage of RMGI is its capability to chemically bond to tooth structure, even in the presence of moist dentin. RMGI reaction can be achieved by both acid-base reaction (induced by glass ionomer component) and polymerization reaction (induced by resin component). Thus, RMGI has better mechanical properties, wear resistance, and improved esthetics compared with conventional glass ionomer. In addition, the coefficient of thermal expansion of glass ionomer which is similar to that of tooth structure, allows for proper marginal adaptation without marginal leakage.

Resin composites have been widely used in dental practice; because of their high mechanical properties, excellent esthetic properties, and ease of clinical application.