Evaluation of Resin Composite Posterior Restorations Using Modeling Resin Insertion Technique Versus Conventional Composite Placement Technique in Class I Lesions: Randomized Clinical Trial

Statement of the problem In a restorative procedure, an important objective is to obtain restorations with smooth surfaces. Surface roughness has a major influence on plaque accumulation, secondary caries, and gingival irritation. Further, it may directly influence wear behavior and the marginal integrity of composite restorations. A roughened surface of a resin composite restoration is also likely to be stained by exogenous sources, such as coffee, tea, or red wine, leading to the discoloration of the material.

One of the main drawbacks of sculpting composite restorations is that some materials are sticky, reducing the ease of handling and insertion of the material into the tooth cavity. Some materials readily adhere to the composite instruments; thus, limiting reestablishment of the shape and anatomical contour of the tooth. As a result, the application of lubricants on the composite instrument such as modeling liquids/resins between the layers of composite have been proposed.

Rationale Modeling resins can be directly applied between the layers using a brush or can be used as a lubricant on manual instruments. In both the aforementioned techniques, the ease of instrumentation during the placement of esthetic restorations is superior, compared to the traditional restorative techniques. Moreover, any pores or gaps on the surface of the composite placed by means of the layering technique can be easily resolved. Hence, the modeling resin facilitates the reduction of defects in the body of the restoration and aids in improving the mechanical properties.

Although these methods are widely used, a potential shortcoming is that these techniques may adversely affect the physical and surface properties of the resin composite. However, it is unknown whether different compositions of adhesives or modeling agents may affect the surface microhardness, surface roughness, and color stability of composites over time.