Evaluation of Clinical Wear and Surface Roughness of Partial Restorations Produced by Additive and Subtractive Manufacturing Methods: A Split-Mouth Randomized Controlled Clinical Trial

In today's dentistry, where aesthetics has gained increasing importance, the use of CAD-CAM in the fabrication of fixed prostheses has become widespread. Although restorations produced by traditional methods are of high quality, they are mechanically and aesthetically affected due to being shaped manually by the dentist (conventional method). Therefore, errors that may occur during fabrication can negatively affect the durability and marginal adaptation of composite restorations. In a study comparing production techniques, composite crowns produced by the direct technique and single crown restorations fabricated using CAD-CAM were examined under an electron microscope. The composite restorations manufactured with the indirect technique showed more porosity, while no porosity was observed in restorations produced with the CAD-CAM method. This result may be attributed to the fact that the prefabricated CAD-CAM blocks are homogeneous and subjected to quality control during production. As a result, internal structural defects are generally not observed in milled products. The absence of porosity is an important factor in the durability and fit of restorations. 3D Printers Restorations produced using 3D printers are among the latest technological advancements in dentistry. Additive manufacturing has been defined by the American Society for Testing and Materials (ASTM) as "the process of joining materials layer upon layer to create objects from 3D model data, as opposed to subtractive manufacturing methodologies." 3D printers have begun to be used in various dental disciplines such as dental education, oral surgery, dental implantology, orthodontics, pedodontics, prosthodontics, and restorative dentistry. In restorative clinics, they can especially be utilized for intracoronal restorations. However, studies in this area remain quite limited. Null hypothesis of this study is that there is no statistically significant difference in clinical wear and surface roughness between single crown indirect restorations fabricated using additive and subtractive manufacturing methods.