The aim of study was to evaluate the stress distribution in implant-supported prostheses and peri-implant bone using internal hexagon (IH) implants in the premaxillary area, varying surgical techniques (conventional, bicortical and bicortical in association with nasal floor elevation), and loading directions (0°, 30° and 60°) by three-dimensional (3D) finite element analysis. Three models were designed with Invesalius, Rhinoceros 3D and Solidworks software. Each model contained a bone block of the premaxillary area including an implant (IH, Ø4 × 10 mm) supporting a metal-ceramic crown. 178 N was applied in different inclinations (0°, 30°, 60°). The results were analyzed by von Mises, maximum principal stress, microstrain and displacement maps including ANOVA statistical test for some situations. Von Mises maps of implant, screws and abutment showed increase of stress concentration as increased loading inclination. Bicortical techniques showed reduction in implant apical area and in the head of fixation screws. Bicortical techniques showed slight increase stress in cortical bone in the maximum principal stress and microstrain maps under 60° loading. No differences in bone tissue regarding surgical techniques were observed. As conclusion, non-axial loads increased stress concentration in all maps. Bicortical techniques showed lower stress for implant and screw; however, there was slightly higher stress on cortical bone only under loads of higher inclinations (60°).
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http://dx.doi.org/10.1080/10255842.2016.1209188 | DOI Listing |
Oper Orthop Traumatol
December 2024
Department of Orthopedics and Traumatology, Centre Hospitalier Universitaire Vaudois, (CHUV), Rue de Bugnon 46, 1011, Lausanne, Switzerland.
Objective: Minimally invasive percutaneous techniques are used to stabilize fractures of the anterior pelvic ring. Stabilization of the fracture facilitates early mobilization and rehabilitation, while percutaneous techniques reduce complications such as infection and bleeding.
Indications: Indicated for patients with non- or minimally displaced fractures of the anterior pelvic ring, or if fracture displacement can be reduced using minimally invasive techniques.
J Hand Surg Glob Online
November 2024
The Curtis National Hand Center, MedStar Union Memorial Hospital, Baltimore, MD.
Purpose: Osteoporotic patients are at risk of peri-implant fractures after distal radius fixation. A unicortical screw in the proximal hole of the plate can theoretically decrease stress riser formation by eliminating the hole in the far bone cortex. This construct has been proposed in orthopedic literature to prevent peri-implant fractures but has not been tested in an osteoporotic distal radius model.
View Article and Find Full Text PDFClin Implant Dent Relat Res
December 2024
Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy.
Introduction: Short implants are today a reliable, minimally invasive option for the rehabilitation of the posterior maxilla. However, maintaining marginal bone stability remains a crucial factor for long-term success, particularly in the case of short implants. The present multicenter prospective case-control study aimed to compare the clinical outcomes of bone-level and tissue-level short implants in the posterior maxilla, focusing on implant survival and peri-implant marginal bone stability over 1 year of function.
View Article and Find Full Text PDFJ Clin Exp Dent
November 2024
Department of Oral Implantology, Faculty of Odonto-Stomatology, University of Medicine and Pharmacy at Ho Chi Minh City.
Background: Severe maxillary resorption presents challenges in dental implant placement. This research aims to assess the feasibility, angular orientation, and appropriate length of pterygoid implants in patients with significant maxillary atrophy.
Material And Methods: The study examined Cone Beam Computed Tomography (CBCT) scans from 60 completely edentulous patients classified as Cawood and Howell's Classes V or VI, with less than 4mm residual bone height in their posterior maxilla.
J Orthop Surg Res
November 2024
Spine Surgery Department, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.
Background: Patients with L4-S1 lumbar degenerative disease (LDD) with osteoporosis are prone to sacral-screw loosening during spinal internal fixation. We aimed to compare the clinical efficacy and imaging results of sacral bicortical, tricortical, and polymethylmethacrylate (PMMA)-augmented pedicle-screw fixation in the treatment of L4-S1 LDD with osteoporosis.
Methods: This is a retrospective study, 72 patients were enrolled and divided into three groups according to the S1-screw fixation method: PMMA-augmented pedicle-screw fixation (Group A, n = 26), bicortical fixation (Group B, n = 22), and tricortical fixation (Group C, n = 24).
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