Claudio Stacchi, DDS, MSc/Francesca Andolsek, DDS, MSc/Federico Berton, DDS, MSc/Giuseppe Perinetti, DDS, MSc, PhD/Chiara Ottavia Navarra, DDS, MSc/Roberto Di Lenarda, DDS, MSc: Purpose: To analyze the occurrence of intraoperative complications during sinus floor elevation with a lateral approach and their correlations with the technique adopted by surgeons. Materials and Methods: Electronic and manual searches resulted in 4,417 records on sinus floor elevation. Twenty-one randomized clinical trials (RCTs) and 11 prospective controlled clinical trials (CCTs) reporting occurrence of intraoperative complications were included. Risk of bias was assessed according to the Cochrane tool and a modified Downs and Black quality analysis for RCTs and CCTs, respectively. Results: Sinus membrane perforation and hemorrhagic events following vascular lesions were the only intraoperative complications reported by the selected studies with overall occurrences of 15.7% and 0.4%, respectively. Three different surgical devices (rotary instruments, piezoelectric osteotomes, and manual bone scrapers) were used to perform the lateral antrostomy. Ultrasonic devices and bone scrapers showed a lower incidence (10.9% and 6.0%, respectively) of membrane perforation compared with that of rotary instruments (20.1%). Among the different ultrasonic procedures, erosion of the lateral antral wall showed the lowest membrane perforations (4.7% incidence). Hemorrhagic complications seemed to be extremely infrequent with any surgical technique. Conclusion: Sinus membrane perforation was the most frequently described intraoperative complication during sinus floor elevation with a lateral approach. Thinning the lateral wall of the sinus before performing the antrostomy (either with ultrasonic devices or manual bone scrapers) seemed to be an important factor in preventing membrane perforation during sinus surgery. Further high-quality RCTs specifically investigating intraoperative complication occurrence are needed.

Early marginal bone loss (MBL) is a non-infective remodeling process of variable entity occurring within the first year after implant placement. It has a multifactorial etiology, being influenced by both surgical and prosthetic factors. Their impact remains a matter of debate, and controversial information is available, particularly regarding implants placed subcrestally. The present multicenter prospective clinical study aimed to correlate marginal bone loss around platform-switched implants with conical connection inserted subcrestally to general and local factors. Fifty-five patients were enrolled according to strict inclusion/exclusion criteria by four clinical centers. Single or multiple implants (AnyRidge, MegaGen, South Korea) were inserted in the posterior mandible with a one-stage protocol. Impressions were taken after two months of healing (T1), screwed metal-ceramic restorations were delivered three months after implant insertion (T2), and patients were recalled after six months (T3) and twelve months (T4) of prosthetic loading. Periapical radiographs were acquired at each time point. Bone levels were measured at each time point on both mesial and distal aspects of implants. Linear mixed models were fitted to the data to identify predictors associated with MBL. Fifty patients (25 male, 25 female; mean age 58.0 ± 12.8) with a total of 83 implants were included in the final analysis. The mean subcrestal position of the implant shoulder at baseline was 1.24 ± 0.57 mm, while at T4, it was 0.46 ± 0.59 mm under the bone level. Early marginal bone remodeling was significantly influenced by implant insertion depth and factors related to biological width establishment (vertical mucosal thickness, healing, and prosthetic abutment height). Deep implant insertion, thin peri-implant mucosa, and short abutments were associated with greater marginal bone loss up to six months after prosthetic loading. Peri-implant bone levels tended to stabilize after this time, and no further marginal bone resorption was recorded at twelve months after implant loading.

Aim. To evaluate, with three-dimensional analysis, the effectiveness of alveolar ridge preservation (ARP) after maxillary molar extraction in reducing alveolar bone resorption and maxillary sinus pneumatization when compared to unassisted socket healing. Methods. Patients were included in the study following inclusion criteria and underwent minimally traumatic maxillary molar extraction followed by ARP using synthetic nanohydroxyapatite (Fisiograft Bone, Ghimas, Italy) (test group) or unassisted socket healing (control group). Cone-beam computerized tomographies (CBCT) were performed immediately after tooth extraction (T0) and 6 months postoperatively (T1). CBCTs were superimposed by using a specific software (Amira, Thermo Fisher Scientific, USA) and the following items were analyzed in both groups: (i) postextractive maxillary sinus floor expansion in coronal direction and (ii) postextractive alveolar bone dimensional changes (both vertical and horizontal). All data were tested for normality and equality of variance and subsequently analyzed by independent samples T-test and Mann–Whitney test. Results. Thirty patients were treated by three centers and twenty-six (test n=13; control n=13) were included in the final analysis. Mean sinus pneumatization at T1 was 0.69±0.48 mm in the test group and 1.04±0.67 mm in the control group (p=0.15). Mean vertical reduction of the alveolar bone at T1 was 1.62±0.49 mm in the test group and 2.01±0.84 mm in the control group (p=0.08). Mean horizontal resorption of crestal bone at T1 was 2.73±1.68 mm in test group and 3.63±2.24 mm in control group (p=0.24). Conclusions. It could be suggested that ARP performed after maxillary molar extraction may reduce the entity of sinus pneumatization and alveolar bone resorption, compared to unassisted socket healing. This technique could decrease the necessity of advanced regenerative procedures prior to dental implant placement in posterior maxilla.