Biomechanical behavior of temporomandibular joint movements driven by mastication muscles.

Surgery of jawbones has a high potential risk of causing complications associated with temporomandibular joint disorder (TMD). The objective of this study was to investigate the effects of two drive modeling methods on the biomechanical behavior of the temporomandibular joint (TMJ) including articular disc during mandibular movements. A finite element (FE) model from a healthy human computed tomography was used to evaluate TMJ dynamic using two methods, namely, a conventional spatial-oriented method (displacement-driven) and a compliant muscle-initiated method (masticatory muscle-driven).

Gradient gyroid Ti6Al4V scaffolds with TiO surface modification: Promising approach for large bone defect repair.

Large bone defects, particularly those exceeding the critical size, present a clinical challenge due to the limited regenerative capacity of bone tissue. Traditional treatments like autografts and allografts are constrained by donor availability, immune rejection, and mechanical performance. This study aimed to develop an effective solution by designing gradient gyroid scaffolds with titania (TiO) surface modification for the repair of large segmental bone defects.

Comparative biomechanics of all-on-4 and vertical implant placement in asymmetrical mandibular: a finite element study.

Background: Clinical scenarios frequently present challenges when patients exhibit asymmetrical mandibular atrophy. The dilemma arises: should we adhere to the conventional All-on-4 technique, or should we contemplate placing vertically oriented implants on the side with sufficient bone mass? This study aims to employ three-dimensional finite element analysis to simulate and explore the biomechanical advantages of each approach.

Methods: A finite element model, derived from computed tomography (CT) data, was utilized to simulate the nonhomogeneous features of the mandible.

[Accurate tissue flap reconstruction method based on the quadratic surface developability for head and neck soft tissue defects].

Soft tissue defects resulting from head and neck tumor resection seriously impact the physical appearance and psychological well-being of patients. The complex curvature of the human head and neck poses a formidable challenge for maxillofacial surgeons to achieve precise aesthetic and functional restoration after surgery. To this end, a normal head and neck volunteer was selected as the subject of investigation.

Biomechanical comparison of all-on-4 and all-on-5 implant-supported prostheses with alteration of anterior-posterior spread: a three-dimensional finite element analysis.

The all-on-4 concept is widely used in clinical practice. However, the biomechanical changes following the alteration of anterior-posterior (AP) spread in all-on-4 implant-supported prostheses have not been extensively studied. Three-dimensional finite element analysis was used to compare the biomechanical behavior of all-on-4 and all-on-5 implant-supported prostheses with a change in anterior-posterior (AP) spread.

3D printed PEKK bone analogs with internal porosity and surface modification for mandibular reconstruction: An in vivo rabbit model study.

Polyetheretherketone (PEEK) and its derivative polyetherketoneketone (PEKK) have been used as implant materials for spinal fusing and enjoyed their success for many years because of their mechanical properties similar to bone and their chemical inertness. The osseointegration of PEEKs is datable. Our strategy was to use custom-designed and 3D printed bone analogs with an optimized structure design and a modified PEKK surface to augment bone regeneration for mandibular reconstruction.

Experimental validation of a new model for mandibular motions.

Long-term excessive forces loading from muscles of mastication during mandibular motions may result in disorders of temporomandibular joint (TMJ), myofascial pain, and restriction of jaw opening and closing. Current analysis of mandibular movements is generally conducted with a single opening, protrusive and lateral movements rather than composite motions that the three can be combined arbitrarily. The objective of this study was to construct theoretical equations reflecting the correlation between composite motions and muscle forces, and consequently to analyze the mandibular composite motions and the tensions of muscles of mastication in multiple dimensions.

Effect of the prosthetic index on stress distribution in Morse taper connection implant system and peri-implant bone: a 3D finite element analysis.

Background: The combination of a prosthetic index with Morse taper connection was developed, with the purpose of making prosthetic procedures more precise. However, the presence of the index may compromise the mechanical performance of the abutment. The aim of this study is to evaluate the effect of prosthetic index on stress distribution in implant-abutment-screw system and peri-implant bone by using the 3D finite element methodology.

3D-printed porous condylar prosthesis for temporomandibular joint replacement: Design and biomechanical analysis.

Background: Customized prosthetic joint replacements have crucial applications in severe temporomandibular joint problems, and the combined use of porous titanium scaffold is a potential method to rehabilitate the patients.

Objective: The objective of the study was to develop a design method to obtain a titanium alloy porous condylar prosthesis with good function and esthetic outcomes for mandibular reconstruction.

Methods: A 3D virtual mandibular model was created from CBCT data.

Biomechanical behavior of mandible with posterior marginal resection using finite element analysis.

This study aims to characterize biomechanical behavior of various designs of posterior mandibular marginal resection under functional loadings using finite element method. The ultimate goal of this work is to provide clinically relevant information to prevent postoperative fracture and to stipulate prophylactic internal fixation for planning of marginal mandibulectomy. A 3D mandibular master model was reconstructed from cone beam computed tomography images.

Evaluation of a custom-designed human-robot collaboration control system for dental implant robot.

Background: The purpose of this study is to develop a methodology to better control a human-robot collaboration for robotic dental implant placement. We have designed a human-robot collaborative implant system (HRCDIS) which is based on a zero-force hand-guiding concept and a operational task management workflow that can achieve highly accurate and stable osteotomy drilling based on a surgeon's decision and robotic arm movements during implant surgery.

Method: The HRCDIS brings forth the robot arm positions, exact drilling location, direction and performs automatic drilling.

Biomechanical and Mechanostat analysis of a titanium layered porous implant for mandibular reconstruction: The effect of the topology optimization design.

A porous scaffold/implant is considered a potential method to repair bone defects, but its mechanical stability and biomechanics during the repair process are not yet clear. A mandibular titanium implant was proposed and designed with layered porous structures similar to that of the bone tissue, both in structure and mechanical properties. Topology was used to optimize the design of the porous implant and fixed structure.

Experimental validation of finite element simulation of a new custom-designed fixation plate to treat mandibular angle fracture.

Background: The objective of the study was to validate biomechanical characteristics of a 3D-printed, novel-designated fixation plate for treating mandibular angle fracture, and compare it with two commonly used fixation plates by finite element (FE) simulations and experimental testing.

Methods: A 3D virtual mandible was created from a patient's CT images as the master model. A custom-designed plate and two commonly used fixation plates were reconstructed onto the master model for FE simulations.

Accuracy of dental implant surgery with robotic position feedback and registration algorithm: An in-vitro study.

Background: The purpose of this study was to develop and validate a positioning method with hand-guiding and contact position feedback of robot based on a human-robot collaborative dental implant system (HRCDIS) for robotic guided dental implant surgery.

Methods: An HRCDIS was developed based on a light-weight cooperative robot arm, UR5. A three-dimensional (3D) virtual partially edentulous mandibular bone was reconstructed using the cone bone computed tomography images.

Topological optimization of 3D printed bone analog with PEKK for surgical mandibular reconstruction.

Purpose: The purpose of this study was to analyze mechanical behaviors of a topologically optimized and 3D-printed mandibular bone block with polyetherketoneketone (PEKK) for surgical mandibular reconstruction.

Materials And Methods: 3D virtual mandibular models were reconstructed from cone beam computed tomography images. A proposed mandibular resection of the mandibular body (40 mm anterior-posteriorly) was segmented.

Photodynamic therapy versus systemic antibiotic for the treatment of periodontitis in a rat model.

Background: To compare the therapeutic effect of photodynamic therapy (PDT) with Toluidine blue O hydrogel versus systemic antibiotic (SA) in treating periodontitis on rats.

Methods: Thirty-two Wistar rats were divided into four groups and treated differently: Negative control (NC) group, normal rats; positive control (PC) group, rats with periodontitis; SA group, rats with periodontitis treated with systemic antibiotic; PDT group, rats with periodontitis treated with PDT. After treatment, gingival sulcus bacterial load was measured by counting the colony forming units per milliliter (CFU mL ).

Biomechanical behavior of mandibles reconstructed with fibular grafts at different vertical positions using finite element method.

Background: For large mandibular defects, surgical reconstruction using microvascular fibular grafts has advantages over other alternatives in terms of blood supply and good quality of grafted bone. However, the fibular segment is usually lower in height than that of the original mandible, meaning that the vertical positioning of the fibular graft is variable, with different biomechanical consequences on the reconstructed mandible.

Objectives: To use finite element method (FEM) to evaluate stress distribution and displacement of a reconstructed mandible versus an intact mandible under occlusal loads.