Proof of Concept of a New 3D-Guided System for a Single Implant Overdenture in the Mandible: An In Vitro Study

To evaluate the precision and efficiency of a novel guide system for single implant placement in the mandibular symphyses and to evaluate whether the outcome is affected by the level of operator experience.

A total of 90 implants were placed in three different mandibular cast types (Cawood and Howell class III, IV, and V). For each model, a complete denture was 3D printed. A polyether ether ketone rail with a guide sleeve was embedded in the middle of the denture. To determine the ideal implant position, the sleeve could be moved in a buccolingual direction. Adjustment of implant angulation was possible, and an angle correction of 0, 12, or 24 degrees was available. A total of 30 clinicians were divided into three groups: group 1 (experienced, n = 10), group 2 (beginner, n = 10), and group 3 (inexperienced, n = 10). Each clinician was asked to plan and perform a guided flapless implant placement in the mandibular symphysis. Two preoperative CBCT scans were taken; the first was to verify the planning, and the second was to adjust the planning if needed. Finally, a postoperative CBCT scan was taken to compare the planning to the final implant position.

Based on the first CBCT, the clinicians adjusted their planning by an average of 1.66 ± 1.65 mm coronally, 2.41 ± 2.44 mm apically, and by a mean angular correction of 6.08 ± 0.77 degrees. After implant placement, the mean deviation from the planned implant position was 0.87 ± 0.58 mm at the coronal aspect and 0.98 ± 0.64 mm at the apical aspect. The mean angular deviation was 6.05 ± 0.71 degrees. Overall, there were no significant differences in coronal and apical deviation (P > .05) based on the level of experience. In terms of angulation, a significant difference was found in both planning (P = .049) and placement (P = .038) between beginners and experienced clinicians.

Guided implant placement of a single implant in the mandibular symphysis using a removable denture with guide sleeve had an acceptable level of accuracy. Clinicians with limited experience spent more time on the procedure, resulting in less angular deviation during implant planning and placement compared to experienced clinicians.