Osteology, Volume 3, Issue 4 (December 2023) – 3 articles

Today, dental implantology represents a reliable technique for treating both partial and total edentulism. The fixation of dentures on dental implants can be achieved using various techniques, where the choice of a specific technique depends on the patient’s individual needs, the jawbone’s condition, and the prosthesis design. Currently, the two most common types of prosthetic abutment connections are cemented and screwed, each with its own set of advantages and disadvantages. This study aimed to analyze a novel Morse cone connection system between the prosthesis and implant using finite element analysis (FEA). The analysis of connection retention was conducted using three different approaches: analytical, in vitro, and FEA. Three-dimensional models were created for systems comprising an abutment, healing cap, and crown under three inclination conditions: 0°, 15°, and 30°. Using Ansys finite element software (R1 2023), the impact of the tilt on the system retention was examined. The FEA showed results comparable with the in vitro studies regarding the retention strength for an abutment cap system with a 4° taper, obtaining 66.6 N compared with the 68 N calculated in our in vitro study. The inclination of the abutment affected the system retention due to the hole made in the abutment’s surface, decreasing the contact area between components. The Morse cone prosthesis–implant connection system was found to be the most stable and efficient compared with threaded or cemented systems. The retention was influenced by factors such as the abutment conicity, insertion strength, and the contact surface between components. Full article

Background: the aim of the study was to assess, through orthopantomograms (OPGs), the existence of peri-implant bone loss of distal implants in implant-supported full-arch mandibular restorations. A comparison between full-arch implant-supported rehabilitations performed in the inter-foraminal region and full-arch rehabilitations that include implant insertion distal to the mental foramen was conducted. Methods: a retrospective observational analysis of 17,950 OPGs from 2010 to 2020 was conducted. The presence of fixed implant-supported prostheses in a fully edentulous mandible was the inclusion criteria of the study. OPGs were divided according to the number of implants (four, six, and eight), position of the implants (mesial or distal to the mental foramen), and positioning patterns (models 1, 2, 3, 4, and 5). Results: a total of 51 OPGs were included in the study, 19 of which showed peri-implant bone loss. In particular, 16 belonged to the six-implant rehabilitation group and 3 to the eight-implant rehabilitation group; none of the four-implant-supported rehabilitations were affected by peri-implant bone loss. In all rehabilitations affected by peri-implant bone loss, the distal implant was the most involved, in particular the implant in positions 36 and 46. Conclusions: implants distal to the mental foramina are more susceptible than mesial implants to bone resorption in full-arch fixed implant-supported prostheses. This significant difference should be investigated further for the presence and synergy of biomechanical factors that could act predominantly in this area, such as mandibular flexure and occlusal loading. Full article

Background: Displaced talar neck fractures are subject to avascular necrosis and degenerative joint disease. A single-lateral-incision approach may avoid damage to the remaining blood supply to the talar body provided by the deltoid artery. The purpose of this paper is to describe the surgical technique for a single approach to talar neck fractures, to evaluate the outcomes in a cohort of patients, and to review the literature on the topic. Method: A retrospective review. Patients were identified at a single medical center and met the following inclusion criteria: closed fracture, type-II talar neck fracture with displacement of the subtalar joint, single lateral operative approach, and radiographic follow-up of at least 6 months. Results: Five patients were identified meeting the inclusion criteria. The mean follow-up was 18 months (12–25). The mean VAS (Visual Analog Score) score at the final follow-up was 1.2 (0–3). Four of five patients returned to running at the final follow-up. The one patient who did not return to running was able to bike and hike. There were no cases of avascular necrosis and no cases of degenerative joint disease. Conclusions: Although a two-incision approach could be considered for all displaced talar neck fractures, there are certain fractures that can be anatomically reduced and stabilized through a single lateral incision which may limit the risk of avascular necrosis. Full article