Comparative Evaluation of Two Different Types of Abutments in Relation to Post-prosthetic Bone Resorption and Periodontal Pocket Depth: A Randomized Controlled Clinical Trial With a One-Year Follow-Up

Background and aim: in the past few years, the number of studies conducted on the designs of abutments and related materials has increased. The restoration is performed over the implant using prefabricated standard abutments. Due to the problems encountered in relation to bone resorption following restoration, other types of abutment designs have been introduced in the dental field such as molded abutments usually fabricated by the lost-wax technique and computer-designed abutments produced by three-dimensional (3D) printing technology. The aim of this study was to compare the clinical performance of molded abutments and computer-designed 3D printed abutments in terms of the bone loss around the implant and the depth of periodontal pockets in a one-year observation period. Methods: The research sample consisted of 32 dental implants for patients who required two adjacent implants. Patients were randomly allocated into two groups: in the first group, the patients received molded abutments, whereas, in the second group, the patients received 3D printed abutments with an allocation ratio of 1:1. In the molded abutment group, the plastic abutments were waxed and poured using the Ni-Cr mixture in the lost-wax technique, while in the printed abutment group, the abutments were designed by a computer program and printed using the Cr-Co mixture employing a 3D laser printer. The bone level and pocket depth around the implant were evaluated at 3, 6, and 12 months following cementation. Results: After one year, there were significant differences in the bone resorption mean values between the 3D laser-printed abutment group (0.43 +/- 0.11) and molded abutment group (0.54 +/- 0.11). In addition, there were significant differences in the mean values of probing depth between the 3D laser-printed abutment group (3.39 +/- 0.12) and molded abutment group (3.53 +/- 0.08). Therefore, the 3D laser-printed abutment was slightly better and had a lower bone loss degree than the molded abutment. Conclusion: Within the limitations of the current work, the mean bone resorption for both types of abutments was within the normal limits. However, the implants that were restored using the printed abutments had less bone resorption than those restored using the molded abutments.