Immediate Placement and Loading of Maxillary Single-Tooth Scalloped Implants and Digitally Customized Restorations: A 5-Year Prospective Study of Marginal Bone Level

Purpose: To evaluate over 5 years the mesial, distal, palatal, and buccal bone levels as well as the buccal bone thickness surrounding scalloped implants that were immediately placed and loaded with provisional crowns fixed on final prefabricated abutments. Materials and Methods: A total of 18 implants were placed and immediately loaded using CAD/CAM technology in 18 patients to replace a single tooth in the anterior maxilla. The marginal bone levels around the scalloped implant necks were measured mesially and distally using intraoral standardized radiographs after crown placement as well as at the 1-, 3-, and 5-year follow-ups. CBCT para-axial cut images were used to measure the bone level buccally and palatally from the implant neck to the bone-to-implant contact (BIC) 5 years after loading. These images were used to evaluate the thickness of the buccal bone at the implant neck and 4 mm apically both immediately after implant placement (T0) and 5 years later. Results: All implants were assessed clinically and radiologically after 5 years. No implant failure was recorded, and the average marginal bone variation for mesial and distal sites was as follows: 0.114 ±0.135 mm at crown cementation, 0.239 ± 0.158 mm 1 year later, 0.233 ± 0.182 mm 3 years later, and 0.180 ± 0.182 mm 5 years later. Our findings indicate that at T0, the average thickness of the buccal bone was 2.27 mm at the implant neck (M0; ranging from 1.9 to 2.4 mm) and 2.33 mm at 4 mm apical to the implant neck (M1; ranging from 1.9 to 2.9 mm). At 5 years postoperative (T4), the mean had decreased to 1.94 mm at M0 (ranging from 1.7 to 2.3 mm) and 2.14 mm at M1 (ranging from 1.8 to 2.4 mm). After 5 years of functional loading, the mean changes at the buccal and palatal bone for all implants were +0.187 ± 0.52 mm and +0.06 ± 0.38 mm, respectively. Minor prosthetic problems were observed over the 5 years, including incisal ceramic chipping in two crowns and replacement of two crowns due to esthetic reasons after 1 year. No loosening of crowns or abutments was reported. Conclusions: Scalloped-neck implants demonstrated a comparable behavior to regular-neck implants with similar designs in immediate placement and temporization protocol over a 5-year period.