Photoelastic analysis of bone deformation in the region of the mandibular condyle during mastication

A finite element analysis of the trapezoidal plate. How to get a stable fixation at different fracture lines?

The fractures in the condylar area are a challenge for every surgeon, for the treatment of which trapezoidal condylar plate is used in most cases. However, it is not possible to position the plate in the ideal osteosynthesis lines according to Meyer et al. in every clinical situation. In many cases, the fracture line is also not in the centre of the trapezoidal plate. The aim of this study is to investigate the osteosynthesis rigidity and the effect of plate localisation relative to the fracture line. In a simulation model in the first group the plate was positioned in the ideal position in the middle of the condylar base, in the second group the plate position was changed - the plate was shifted upwards until the fracture passed underneath the centre of the plate again and in the last group the plate was moved further down so that the fracture passes underneath the middle of the plate. Heterogeneity of the bone was simulated using different sets of biomechanical properties. In the experiment, the joints were fully constrained and a force of 500 N was applied to the opposite side. An interaction between bone and plate was completely excluded and the stability of the plates as well as the mobility of the bone fragments was analysed. The results have shown that an inferior position of the fracture line leads to greater mobility of the fragments if the position of the osteosynthesis material is the same. With a deep fracture line, a more cranial positioning of the plate leads to better stabilisation. This study needs to be experimentally validated.

Influence of Method of Treatment of Mandibular Condylar Fractures on Range of Articular Path Measured by Cadiax Device

Background/Objectives: The aim of this study was to evaluate the function of the treated temporomandibular joint based on the analysis of the image of the articular path using the Cadiax device depending on the choice of treatment method for unilateral condylar fracture of the mandible. Methods: Sixty patients who were treated for condylar fractures of the mandible at the Maxil-lofacial Surgery Department in Katowice were qualified for the analysis of the range of movements of the mandibular heads using the Cadiax device. From the group of patients who suffered fractures of the mandible, including condylar processes, patients were finally qualified for the measurement of the articular path of the injured and healthy joint according to strict criteria. Results: The condylar examination was performed in 20 patients who had conservative condylar fracture treatment and 40 patients who underwent various surgeries in the course of a single condylar fracture. The control group consisted of 20 patients whose mean values for the articular pathway measured for both sides were 12.73 and 12.69 and fell within the standard developed for healthy joints tested with the Cadiax device. Conclusions: We have achieved an almost ideal treatment for condylar fractures. We are also beginning to notice the need for rehabilitation of patients after this type of surgery.

Evaluation of the Efficacy of Three Times Titanium Plate Gradual Fixation Method in the Treatment of Extracapsular Condylar Fractures

OBJECTIVE

An improved method of treating inwardly dislocated mandibular extracapsular condylar fracture-three times titanium plate gradual fixation method was introduced, and the clinical efficacy of this method was evaluated.

METHODS

Twenty patients with extracapsular condylar fractures who underwent surgical treatment using the three times titanium plate gradual restoration and fixation method in the Department of Oral Craniomaxillofacial Surgery of the Ninth People's Hospital of Shanghai from November 2020 to June 2023 were selected as the study subjects.

RESULTS

After condylar restoration 22 sides reached healing and 1 side was basically healed; in 3 months after the operation, the degree of opening the mouth and the type of the opening of the mouth reached normal, and 1 case had mildly poor occlusion, which required to be further adjusted through orthodontics, and there was no temporomandibular function disorder or facial nerve function damage.

CONCLUSION

Three times of gradual fixation with a titanium plate can make the condylar process achieve precise and stable repositioning, and make the surgical process orderly, and it is a kind of reliable fixation method for extracapsular condylar fractures.

Two Miniplates Versus Three Dimensional Plate in Management of Mandibular Condylar Fractures: A Systematic Review and Meta-Analysis

Study Design

Systematic Review and Meta-analysis.

Objective

This systematic review and meta-analysis aimed to compare the efficacy of 2 miniplates vs a three-dimensional plate in the management of mandibular condylar fractures. The primary objective was to assess key parameters, including intraoperative time, maximum mouth opening, complications, and functional outcomes, to determine potential differences between the 2 fixation methods.

Methods

A comprehensive literature search was conducted to identify relevant studies. Inclusion criteria were applied, and the selected studies underwent systematic review. The key parameters were extracted and subjected to meta-analysis to quantify and compare the outcomes associated with the use of 2 miniplates and three-dimensional plates. The methodologies of the included studies were critically evaluated to address potential biases and confounding factors.

Results

The meta-analysis results indicated that there were no statistically significant differences between the 2 fixation methods in terms of intraoperative time, maximum mouth opening, complications, and functional outcomes. However, concerns were raised regarding the high risk of bias, confounding factors, and considerable heterogeneity observed across the reviewed studies.

Conclusions

The findings suggest that both 2 miniplates and three-dimensional plates are viable options for the management of mandibular condylar fractures. Despite the lack of statistical significance in the observed differences, the study highlights the need for further prospective research with enhanced methodologies, standardized protocols, larger sample sizes, and reduced bias to refine our understanding and potentially influence clinical management protocols.

A single-centre retrospective 10-year experience of the rhombic 3D condylar fracture plate for open reduction and internal fixation of condylar neck and base fractures

Fractures of the mandibular condyle account for a significant proportion of mandibular fractures. The specific functional loads require particular specifications for the implant design used for open reduction and internal fixation of such fractures. The clinical and radiographic outcomes in patients treated using a single rhombic 3D condylar fracture plate for open reduction and internal fixation at a single institution, and who fulfilled the inclusion and exclusion criteria, are presented. The primary outcome variables were: occlusion, maximum interincisal distance and mandibular excursion at 1, 3, and 6 months postoperatively, and radiographic measurements for mandibular height and gonion angle. In total, 263 patients were included, of whom 173 (65.8%) were male and 90 (34.2%) female. The mean age was 40.4 ± 18.9 years. There was satisfactory occlusion in 98.9% of patients at the 6-month follow-up, and a significant improvement in all parameters for mandibular excursion (p < 0.001), with a reduced ramus height and an increase in the gonion angle on the fractured side. Excellent clinical and radiographic results were achieved using the rhombic-shaped implant, deeming it appropriate for the osteosynthesis of mandibular condyle fractures.

Dynamic imaging of force chains in 3D granular media

Granular media constitute the most abundant form of solid matter on Earth and beyond. When external forces are applied to a granular medium, the forces are transmitted through it via chains of contacts among grains-force chains. Understanding the spatial structure and temporal evolution of force chains constitutes a fundamental goal of granular mechanics. Here, we introduce an experimental technique, interference optical projection tomography, to study force chains in three-dimensional (3D) granular packs under triaxial shear loads and illustrate the technique with random assemblies of spheres and icosahedra. We find that, in response to an increasing vertical load, the pack of spheres forms intensifying vertical force chains, while the pack of icosahedra forms more interconnected force-chain networks. This provides microscopic insights into why particles with more angularity are more resistant to shear failure-the interconnected force-chain network is stronger (that is, more resilient to topological collapse) than the isolated force chains in round particles. The longer force chains with less branching in the pack of round particles are more likely to buckle, which leads to the macroscopic failure of the pack. This work paves the way for understanding the grain-scale underpinning of localized failure of 3D granular media, such as shear localization in landslides and stick-slip frictional motion in tectonic and induced earthquakes.

Incidence of Facial Nerve Injury and Sialocele Formation Following Mandibular Condylar and Sub-condylar Fracture Fixation

Purpose

To study the incidence of sialocele formation in the parotid gland and to study the incidence of facial nerve affliction following treatment of mandibular condylar and sub-condylar fractures.

Materials and methods

The present study is a retrospective study conducted on a total of 82 patients with 107 sub-condylar and condylar fractures treated in this centre from August 2008 to August 2020. The surgical approaches used to treat the fractures were considered, and the occurrence of sialocele, salivary fistula and facial nerve paralysis was noted. The facial nerve function was analysed using House-Brackmann system of classification.

Results

The incidence of sialocele formation was seen in 15.87% of cases, and the incidence was seen more commonly during a preauricular approach (52.94%) followed by retromandibular (41.17%) followed by anterior parotid transmassetric approach (11.76%). The incidence of facial nerve affliction was seen in 17.57% of cases with majority of them showing temporal branch involvement in 21.05% of cases.

Conclusion

During the treatment of condylar and sub-condylar fractures, the facial nerve is at considerable risk of damage; however, understanding the anatomy of the nerve is of importance to avoid such complications. Sialocele formation is also an undesirable complication of such surgeries, a prompt diagnosis and early treatment is mandatory to overcome further unwanted sequel.

The "low preauricular" transmasseteric anteroparotid (TMAP) technique as a standard way to treat extracapsular condylar fractures

Condylar fracture treatment is a debated topic among maxillofacial surgeons. Various surgical techniques are used today, each one with advantages and disadvantages. The aim of this study is to present and evaluate our technique adopted for treatment of any type of extracapsular condylar fractures. Between 2020 and 2022, 16 condylar fractures were treated. In two patients with bilateral condylar fractures, the present technique was compared to the mini-retromandibular approach. All the patients were checked for clinical and radiological outcomes, facial nerve injury, scar visibility and presence of salivary complications. Dental occlusion was always restored, and facial nerve damage or salivary disorders were not observed. The skin incision, limited to the caudal two-thirds of the auricle, made the scar almost invisible and greatly improved the surgical field in the condylar neck area, facilitating the treatment. The proposed technique provides easier internal fixation for both neck and base condylar fractures with good cosmetic results, ensuring better protection of the facial nerve and parotid gland. The surgical technique described has not shown disadvantages in terms of operational difficulty, results, and complications. This novel surgical technique could represent a new choice in the treatment of extracapsular condylar fractures, although further studies are needed to support this new proposal.

Evaluation of the pattern of fracture formation from trauma to the human mandible with finite element analysis. Part 2: The corpus and the angle regions

BACKGROUND/AIMS

Although the mandible is the largest and strongest bone of the facial skeleton, it is frequently broken. The fracture location in the mandible depends on the biomechanical features, direction and angle of the trauma, and masticatory muscles. This study aimed to evaluate the stresses caused by trauma to the corpus and angle regions from different angles.

MATERIALS AND METHODS

After computer-based mandible models were created using finite element analysis, a force of 2000 Newton(N) was simulated with the mouth open or closed to the corpus and the angle. To the corpus: at 90° (Model 1) in the lateromedial direction, 45° (Model 2) in the lateromedial-inferosuperior direction, and 90° (Model 3) in the inferosuperior direction. To angle: 90° (Model 4) in the lateromedial direction and 45° (Model 5) in the lateromedial-inferosuperior direction. The resulting stress intensity was assessed using FEA.

RESULTS

Following the simulated forces, the maximum stress in the mandible occurred in the condylar region, except in Model 3 (Left(L)Corpus2[36 megapascals(MPa)]) in the mouth-closed condition. After traumas in Model 1 (open-mouth: LCondyle2[547 MPa]) and Model 4 (closed-mouth: LCondyle2[607 MPa]), higher stress values occurred in the condyle. In the mouth open-closed state, there was no significant stress change in the condyle region in Model 1 (open-mouth: LCondyle2[547 MPa], closed-mouth:LCondyle2[546 MPa]) or in Model 2 (open mouth: Right(R)Condyle2[431 MPa], closed-mouth:LCondyle2[439 MPa]). In Model 3, lower stress values occurred in the closed-mouth rather than the open-mouth (LCondyle1[167 MPa]) state. In Models 4 and 5, the stress values increased in the mouth-closed condition compared with the mouth-open condition.

CONCLUSIONS

Stress in the mandible is affected by the location of the trauma and the angle of incidence of the blow. In trauma to both the corpus and the angle, the most common area to be fractured is the condyle.

A, Srivastav S, P.G. G, Kumar P, Chaudhry K. Treatment Outcome Comparison Between two 3-Dimensional Plates (Y-Shaped Plate Versus Trapezoidal Condylar Plate) in Management of Mandible Condylar Fracture: A Randomized Control Trial

Aim

To compare the treatment outcomes (clinical, functional and radiographical) using the two different 3-Dimensional plates in open reduction internal fixation of mandibular condylar fracture (MCF). Assessment of ease of fixation and fixation time were also performed.

Methodology

20 MCF patients were divided equally into two groups (Group A: Trapezoidal Condylar Plate and Group B: Y-shaped plate) and the treatment outcomes were compared. Intraoperatively time required for fixation was also compared. The patients were followed up at different timelines till 3 months.

Result

Baseline parameters had statistically insignificant distribution in both groups implying effective randomization and balanced confounding factors. Intraoperatively, adequate anatomical reduction was achieved in both groups with statistically insignificant difference in time required for fixation. Postoperatively, no statistically significant difference was found in radiographic and functional parameters. None of the patients in either group reported with facial nerve injury, condylar resorption, Temporomandibular Disorders. However, 02 patients in Group A and 01 patient in Group B presented with infection, parotid fistula, and hardware failure respectively with statistically insignificant difference.

Conclusion

This study concluded that the treatment outcomes were satisfactory with the use of both 3-D plate, but further studies with larger sample size and longer follow up are required.

Evaluation of the pattern of fracture formation from trauma to the human mandible with finite element analysis. Part 1: Symphysis region

BACKGROUND/AIM

The mandible is the largest, strongest bone in the maxillofacial region. When a fracture occurs in the mandible, its location depends on several factors: the direction of the trauma, the angle of the trauma, masticatory muscles and the quality of the bone. The aim of this study was to evaluate the stresses caused by trauma to the symphysis region from different angles.

MATERIALS AND METHODS

Computer-based mandible models were created, and a 2000 N force was applied to the symphysis at three different angles using finite element analysis. Six trauma situations were simulated with the mouth open or closed. Forces were applied to the symphysis at 90° (Model 1) in the anteroposterior direction, 45° (Model 2) in the anteroposterior-inferosuperior direction and 90° (Model 3) in the inferosuperior direction, when the mouth was open or closed. The resulting stress intensity was assessed using finite element analysis.

RESULTS

As a result of trauma applied to the symphysis region, maximum stresses were found where the impact originated and at the condyle region (Model 2, open mouth: condyle 1 [1172 MPa]). The open mouth position caused higher stress values than the closed mouth position (Model 2, open mouth: condyle 1 [1172 MPa]; closed mouth: symphysis 4 [82 MPa]). The Model 2, open-mouth state (Model 2, open mouth: condyle 1 [1172 MPa]) sustained higher stresses than all the other models.

CONCLUSION

The stress values in the mandible were affected by the force applied to the symphysis region, the angle of impact arrival and the open or closed state of the mouth. Keeping the mouth closed at the time of trauma reduced the stress value. A closed mouth during trauma directed at the symphysis reduced the possibility of mandible fractures.

Evaluation of trabecular bone and mandibular cortical thickness in adults with different vertical facial types

OBJECTIVES

This study investigated differences in trabecular structure and mandibular cortical thickness in adults related to vertical facial type (VFT), sex, and their interactions.

STUDY DESIGN

Lateral cephalometric radiographs (LCRs) and panoramic radiographs (PRs) of 256 patients were reviewed. The VFT classification into low-angle, normal, and high-angle groups was determined using angular and linear measurements on LCRs. Fractal dimension (FD) values and mandibular radiomorphometric indices (RMIs) were calculated on PRs.

RESULTS

Two-way analysis of variance revealed significant differences in FD overall among VFT groups in all sites (P < .001), with pairwise comparisons indicating the greatest values in the high-angle group in the condyle (P < .05) but in the low-angle group elsewhere (P < .001). RMIs were significantly different overall regarding VFT only in the posterior mandible (P = .004), with pairwise comparisons revealing low-angle and normal group values greater than high-angle group values (P < .05). Patient sex and the interaction of facial type and sex had no significant effect on any bone measurements.

CONCLUSIONS

VFT had significant effects on trabecular structure at all measured sites, but cortical thickness was affected only in 1 location.

A dual osteoconductive-osteoprotective implantable device for vertical alveolar ridge augmentation

Repair of large oral bone defects such as vertical alveolar ridge augmentation could benefit from the rapidly developing additive manufacturing technology used to create personalized osteoconductive devices made from porous tricalcium phosphate/hydroxyapatite (TCP/HA)-based bioceramics. These devices can be also used as hydrogel carriers to improve their osteogenic potential. However, the TCP/HA constructs are prone to brittle fracture, therefore their use in clinical situations is difficult. As a solution, we propose the protection of this osteoconductive multi-material (herein called “core”) with a shape-matched “cover” made from biocompatible poly-ɛ-caprolactone (PCL), which is a ductile, and thus more resistant polymeric material. In this report, we present a workflow starting from patient-specific medical scan in Digital Imaging and Communications in Medicine (DICOM) format files, up to the design and 3D printing of a hydrogel-loaded porous TCP/HA core and of its corresponding PCL cover. This cover could also facilitate the anchoring of the device to the patient's defect site via fixing screws. The large, linearly aligned pores in the TCP/HA bioceramic core, their sizes, and their filling with an alginate hydrogel were analyzed by micro-CT. Moreover, we created a finite element analysis (FEA) model of this dual-function device, which permits the simulation of its mechanical behavior in various anticipated clinical situations, as well as optimization before surgery. In conclusion, we designed and 3D-printed a novel, structurally complex multi-material osteoconductive-osteoprotective device with anticipated mechanical properties suitable for large-defect oral bone regeneration.

Application of the lambda plate on condylar fractures: Finite element evaluation of the fixation rigidity for different fracture patterns and plate placements

PURPOSE

The treatment challenges of condylar fractures necessitated the production of several plate designs. Among the relatively new plate designs is the lambda plate, for which biomechanical and clinical data are lacking. The purpose of this study is to examine the rigidity of fixation achieved when the lambda plate is applied to different fractures of the condylar neck and base.

METHODS

Five fractures of the condylar area were designed on a virtual model of a healthy mandible obtained from a CT scan. The fractures were reduced using the lambda plate. For the same fractures, alternative placements of the plate were simulated. The generated models were analysed using the finite element analysis for a 500 N bite load. The displacement of the two condylar fragments along the fracture line was calculated as an indicator of the rigidity of the fixation.

RESULTS

The displacement along the fracture was less than 0.144 mm for the neck fractures and greater than 0.165 mm for the fractures of the condylar base. A more cranial placement of the plate for the neck fractures further reduced the displacement, while a more anterior placement of the plate for the base fractures resulted in displacements greater than 0.330 mm.

CONCLUSION

According to our study, the lambda plate offers better rigidity when applied as cranially as possible for condylar neck fractures. The lambda plate did not provide adequate fixation for base fractures. A second plate at the sigmoid notch should be considered to achieve better stabilization along the fracture if the lambda plate is eventually used.

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. A condylar defect model was subsequently created by virtual condylectomy on the initial mandibular model. The segmented condylar defect model was reconstructed by either solid or porous condyle with a fixation plate. The porous condyle was created by a density-driven modeling scheme with an inhomogeneous tetrahedral lattice structure. The porous condyle, supporting fixation plate, and screw locations were topologically optimized. Biomechanical behaviors of porous and solid condylar prostheses made of Ti-6Al-4V alloy were compared. Finite element analysis (FEA) was used to evaluate maximum stress distribution on both prostheses and the remaining mandibular ramus.

RESULTS

The FEA results showed levels of maximum stresses were 6.6%, 36.4% and 47.8% less for the porous model compared to the solid model for LCI, LRM, and LBM loading conditions. Compared to the solid prosthesis, the porous prosthesis had a weight reduction of 57.7% and the volume of porosity of the porous condyle was 65% after the topological optimization process.

CONCLUSIONS

A custom-made porous condylar prosthesis with fixation plate was designed in this study. The 3D printed Ti-6Al-4V porous condylar prosthesis had reduced weight and effective modulus of elasticity close to that of cortical bone. The.

Reliability of a Trapezium Miniplate with Endoscope-Assisted Internal Fixation in Mandibular Subcondylar Fractures: A Three-Dimensional Analysis

This study aimed to evaluate the reliability of a trapezium plate for open reduction and internal fixation (ORIF) of mandibular subcondylar fractures with the simultaneous use of an endoscope. We selected and retrospectively studied 18 patients (12 males and 6 females) with unilateral mandibular subcondylar fractures who visited the Wonju Severance Christian Hospital. The mean age of the patients was 43.43 ± 15.76 years. Patients underwent ORIF with trapezium miniplate application through an intraoral incision under general anesthesia. The clinical and radiographic findings of the fractured side were compared with those of the non-operated side at 6 months follow-up. All occlusions became stable, and transient functional disturbances disappeared within 6 months of periodic follow-up. Functional mandibular movement recovered within the normal range, with an average mouth opening of 41.5 mm, protrusion of 7.5 mm, and lateral excursion of 7 mm at 6 months. Radiographic controls and statistical analysis confirmed a decent anatomical reduction in all 18 cases. In conclusion, the use of a trapezium miniplate with endoscope-assisted ORIF in mandibular subcondylar fractures can be useful for fixation and functional recovery.

Semi-Rigid Fixation Using a Sliding Plate for Treating Fractures of the Mandibular Condylar Process

Occlusal displacement often occurs after surgery for condylar process fractures because it is difficult to reduce these fractures precisely. However, performing semi-rigid fixation using a sliding plate may overcome this limitation. A retrospective clinical comparison between semi-rigid and rigid fixations was performed. Among 34 patients who had unilateral condylar process fractures, 17 were treated with rigid fixation and the remaining with semi-rigid fixation using a sliding plate. For all patients, panoramic radiographs were collected 1 day and 6 months after surgery. In these radiographs, ramus height and condylar process inclination were measured, and the differences between the fractured and normal sides were assessed. Additionally, the radiographic density of the fracture area was measured. Differences in surgical outcomes and operative times between the two groups and changes in postoperative deviations within each group were analyzed. There was no statistically significant difference in ramus height and condylar process inclination between the two groups at postoperative day 1 and 6 months. Radio-density was observed to be higher in the rigid fixation group, and it increased with time in both groups. The semi-rigid fixation group had a significantly shorter operative time than the other group did. Semi-rigid and rigid fixations showed no differences in terms of effectiveness and outcomes of surgery. In terms of operative time, semi-rigid fixation was superior to rigid fixation.

New protocol for simplified reduction and fixation of subcondylar fractures of the mandible: a technical note

The dilemma regarding the management of condylar fractures generally revolves around the surgical approach, implant design, and the surgeon’s experience. Zide and Kent’s guidelines streamlined the decision making process for condylar fractures. However, there exists no standardized protocol for reduction and fixation of condylar fractures. Here, we have described a detailed and stepwise protocol, common to any surgical approach, that would lead to predictable, reproducible, and repeatable results in every surgeon’s hands.

Biomechanical evaluation of the human mandible after temporomandibular joint replacement under different biting conditions

Temporomandibular joint (TMJ) replacement with an implant is only used when all other conservative treatments fail. Despite the promising short-term results, the long-term implications of TMJ replacement in masticatory function are not fully understood. Previous human and animal studies have shown that perturbations to the normal masticatory function can lead to morphological and functional changes in the craniomaxillofacial system. A clearer understanding of the biomechanical implications of TMJ replacement in masticatory function may help identify design shortcomings that hinder their long-term success. In this study, patient-specific finite element models of the intact and implanted mandible were developed and simulated under four different biting tasks. In addition, the impact of re-attaching of the lateral pterygoid was also evaluated. The biomechanics of both models was compared regarding both mandibular displacements and principal strain patterns. The results show an excessive mediolateral and anteroposterior displacement of the TMJ implant compared to the intact joint in three biting tasks, namely incisor (INC), left moral (LML), and right molar (RML) biting. The main differences in principal strain distributions were found across the entire mandible, most notably from the symphysis to the ramus of the implanted side. Furthermore, the re-attachment of the lateral pterygoid seems to increase joint anteroposterior displacement in both INC, LML and RML biting while reducing it during LGF. Accordingly, any new TMJ implant design must consider stabilising both mediolateral and anteroposterior movement of the condyle during biting activities and promoting a more natural load transmission along the entire mandible.

Finite element analysis of different titanium miniplates: Evaluation of three-dimensional designs applied on condylar neck fractures

INTRODUCTION

The fixation of condylar neck fractures is raising difficulties and for this reason, many plate designs have been developed. The current study compares the performance of four miniplates used in the condylar neck.

MATERIAL AND METHODS

A virtual condylar neck fracture in a mandible obtained from a CT scan was fixed with four miniplates (two straight miniplates, lambda, strut, and trapezoidal). Using finite element analysis, we examined the fragments' displacements and stress distribution in the titanium material and bone. The models were analyzed under two loading conditions: a reduced bite force of 135 N and a force of 500 N.

RESULTS

No risk of material failure was observed. For a load of 135 N, all four plates offer an adequate fixation. For 500 N of applied loading, the lambda and strut plates showed the best rigidity and lowest bone strains. The two parallel plates showed the lowest rigidity and the trapezoidal plate the highest bone strains around all screws.

DISCUSSION

These findings imply that three-dimensional miniplates (lambda, strut) perform better when higher loads are applied. On the other hand, the trapezoidal plate has an increased risk of screw loosening and the two straight plates higher mobility of the fragments.

Evaluation of 3D Trapezoidal Plates in Open Reduction and Internal Fixation of Subcondylar Fractures of Mandible: A Clinical Trial

Background  Fractures of the mandibular condyle are common and account for 25% to 50% of all fractures of the mandible. Various methods exist for open reduction and internal fixation (ORIF) of condylar fractures. This study was done to explore three-dimensional (3D) plates as a viable option. Aim  This study aims to evaluate the effectiveness of 3D trapezoidal plates in open reduction and internal fixation of subcondylar fractures. Materials and methodology This was a non-randomized clinical trial conducted on 20 patients who reported at the Department of Oral and Maxillofacial Surgery, Tamil Nadu Government Dental College and Hospital, Chennai, India. The ORIF was done under general anesthesia. A retromandibular transmasseteric approach was used to expose the fracture site, and the fracture was stabilized using 3D titanium trapezoidal plates. Parameters, such as mouth opening, mandibular deviation, occlusion, surgical accessibility, fracture reduction, adaptability, the difference in ramal height, angulation of the fractured condyle, operative time, facial nerve weakness, implant failure, complications, and scar formation were assessed. Statistical analysis was done using Statistical Package for Social Sciences (SPSS), version 21 (IBM SPSS Statistics for Windows, Armonk, NY). Results  There was an improvement in mouth opening and occlusion in the immediate postoperative period. The surgical accessibility ranged from good to excellent. The fracture reduction was excellent in 60% of patients and good in 40%. In one patient, there was a transient weakness of the marginal mandibular nerve which recovered by three months. Another patient had a wound infection that subsided within the first postoperative week. None of the patients had a device failure during the six-month follow-up period. Conclusion  The trapezoidal 3D plates could be considered as a viable option for treating subcondylar fractures of the mandible in terms of surgical accessibility, stability, ease of device placement, stability of reduced fracture, reduced osteosynthesis material requirement, and minimal damage to the surrounding tissues.

Stability of bioabsorbable fixation systems according to different locations of mandibular fracture: A three-dimensional analysis

This study aimed to elucidate whether the stability of an unsintered hydroxyapatite particles/poly-_l-lactide (uHA/PLLA) system is comparable with that of titanium, according to different load-bearing areas of the mandible. The study included patients who underwent open reduction and internal fixation of the mandibular body, angle, or subcondylar fracture. The stability of uHA/PLLA systems was compared between the immediate and 6-month postoperative time points using three-dimensional cone-beam CT image analysis. The positional changes of each landmark were measured in three-dimensional (3D) coordinate systems using simulation software. Among 36 patients, there were more displacements of the landmarks between the immediate and 6-month postoperative time points after subcondylar fracture reduction than after body or angle fracture reductions. Strong upward displacements of the landmarks after subcondylar fracture reduction were found in the lateral pole [mean (SD) = 1.75 (3.16), p-value = 0.003] and medial pole [mean (SD) = 1.64 (2.50), p-value = 0.024], but not in the center. Subgroup analyses revealed similar unstable results in males on the condylar landmarks after subcondylar fracture reduction. There were tendencies for lateral displacement of the coronoid process in the body fracture group [mean (SD) = 0.8 (0.83)] and angle fracture group [mean (SD) = 0.75 (0.58)] postoperatively (p-value = 0.01). This study concluded that bioresorbable osteosynthesis can be recommended for body or angle fractures, while the indication for subcondylar fractures is less clear.

Does Three-Dimensional Plate Offer Better Outcome and Reduce the Surgical Time Following Open Reduction and Internal Fixation of Adult Mandibular Unilateral Subcondylar Fractures. A Randomized Clinical Study

PURPOSE

The management of the condyle fractures continue to be a source of perineal controversy in the field of oral and maxillofacial trauma. The aim of this study was to compare the surgical feasibility, functional outcome, and stability of fixation between the conventional miniplate and 3-dimensional plate in the management of adult mandibular unilateral subcondylar fractures.

MATERIALS AND METHODS

A prospective randomized clinical study with well-structured inclusion and exclusion criteria was carried out. Patients were allocated into Group A (Miniplates) and Group B (3-D Plates). The primary outcome variables were time taken for fixation, maximum mouth opening, occlusal stability, increase in angulation, and increase in the gap between fractured segments in the radiograph. The secondary outcome variables were needed for intermaxillary fixation (IMF) with guiding elastics and jaw movements. Statistical analysis was done using χ² test and student's t test with P value less than 0.05 indicating statistical significance.

RESULTS

Forty-four patients (40 male and 4 female) were enrolled, with 22 patients in each group. Time taken for fixation using 3-D plates was significantly lower than conventional miniplates (9.6 ± 0.9 minutes with P value 0.001). Although clinical parameters showed improved results for Group B, there was no statistical significance. Radiological parameters ie increase in angulation, and increase in the gap, showed statistically significant results. Group A had significant increases in the angulation of the fractured condyle at the end of the third and sixth months with a P value of 0.008 and 0.0001, respectively. The gap between the fractured segments was significantly increased in Group A at the end of the first and third months, with a P value of 0.022 and 0.003, respectively.

CONCLUSIONS

Our results concluded that 3-D plate offers superior fracture fragment stability and less displacement of the fractured segments. It has an added advantage of the ease of adaptation and shorter operating time.

Analysis between Retromandibular and Periangular Transmasseteric Approach for Fixation of Condylar Fracture - A Prospective Study

Introduction:

Condylar fractures make up for an average of 17.5%–52% of all mandibular fractures. The aim of the present study was to compare the ease, success, and complications between retromandibular and periangular transmasseteric approaches when used for open reduction and internal fixation of condylar fractures.

Materials and Methods:

A total 20 cases with condylar fracture, ten each for retromandibular and periangular transmasseteric approach, were included in the study. Patients were evaluated at 1 week, 1 month, 3 months, and 6 months. Postoperative occlusion, maximum mouth opening, range of movement, facial nerve function, visibility, convenience of plating, and time taken for exposure, fixation, and closure were recorded. Incidence of complications such as wound dehiscence, wound infection, hematoma, sialocele formation, Frey's syndrome, and hypertrophic scars were also evaluated.

Results:

The mean exposure time in the retromandibular approach was 10 min 31 s and 9 min 17 s in the periangular transmasseteric approach. The incidence of facial nerve injury was 2 of 10 patients in the retromandibular group and 3 of 10 patients in the periangular transmasseteric group, all of which resolved within 6 months. The incidence of sialocoele was 2 of 10 in the retromandibular group. The time taken for exposure of the fracture site was statistically significant between the two approaches (P = 0.048) with longer time required for retromandibular approach.

Discussion:

It can be summarized that both the approaches are comparable and well suited for surgical management of condylar fractures. It was observed that in displaced condylar neck fractures, greater difficulty was experienced in the periangular transmasseteric approach than the retromandibular approach.

Clinico-anatomical classification of the processus condylaris mandibulae for traumatological purposes

Mandible condyle fracture has been reported to constitute 9-45 % (Asprino and Consani, 2006), 14.1 % (Bataineh, 1998), 25-50 % (Silvennoinen, Iizuka, 1992), 32 % (Chrcanovic et al., 2004), and 38 % (Brasileiro and Passeri, 2006) of all mandible fractures (Kozakiewicz and Swiniarski, 2013). Small bone segments, limited available space for application of the fixation material and limited visibility of the operative field are common difficulties. To guarantee satisfactory treatment effects, anatomical reduction and proper fracture stability are necessary. The use of 3-4 screws in the upper section (proximal segment) provides adequate immobilization, which can be easily achieved when the condyle is low and wide. However, if the condyle is slender, it is not technically possible to fix 2 plates and 4 screws for osteosynthesis. Selection of the appropriate fixative material that will provide adequate rigidity during the healing period while simultaneously allowing proper construction of the lateral silhouette of the processus condylaris mandibulae to fix the plate remains a key consideration. The aim of this study was to evaluate clinico-anatomical classification of the condyle of mandible posture for traumatological purposes. Five hundred computer tomography virtual models were created, from which 11 measurements were made, and 2 indexes were calculated. Assessment of types based on the ratio of the condyle height index revealed a dichotomous division into high and short condyles. Statistically associated with the division, the Width_neck_basal (the width of the bone at the level of semilunar notch measured by a frontal projection perpendicular to line "A", as described by Neff (Neff et al., 2014)) measurement allowed the creation of the following clinico-anatomical classification: -slender-type condyles have a Width_neck_basal in the range of 4-8.5mm; -squad-type condyles have a Width_neck_basal in the range of 11.5-19.5mm. Patients with a Width_neck_basal value in the 8.5-11.5mm range cannot be classified using this method, and a different method to assess the lateral condylar silhouette must be used. The proposed clinic-anatomical classification method avoids the problems associated with incorrect osteosynthesis plate selection. Assignment to a group can be obtained by making one measurement (the Width_neck_basal). In that way, the optimal fixing material can be selected by the surgeon before the operation commences, with great intraoperation time savings.

Biomechanical evaluation of unilateral subcondylar fracture of the mandible on the varying materials: A finite element analysis

Fixation materials used in the surgical treatment of subcondylar fractures contribute to successful clinical outcomes. In this study, we simulated the mechanical properties of four fixation materials [titanium (Ti), magnesium alloy (Mg alloy), poly-L-lactic acid (PLLA), and hydroxyapatite/poly-L-lactide (HA-PLLA)] in a finite-element analysis model of subcondylar fracture. Two four-hole plates were fixed on the anterior and posterior surfaces of the subcondyle of the mandible. In the simulation model of a subcondylar fracture, we evaluated the stress distribution and mechanical deformation of fixation materials. The stress distribution conspicuously appeared on the condylar neck of the non-fractured side and the center of the anterior plate for all materials. More stress distribution to the biologic component appeared with HA-PLLA than with Ti or Mg alloy, but its effects were less prominent than that of PLLA. The largest deformation was observed with PLLA, followed by HA-PLLA, Mg alloy, and Ti. The results of the present study imply the clinical potential of the HA-PLLA fixation material for open reduction of subcondylar fractures.

A Retrospective Study of Condylar Fracture Management in a Tertiary Care Hospital-A 10-Year Experience

Introduction

Since the advent of rigid fixation, there has been a paradigm shift in the management of condylar fractures from closed treatment options to open reduction and rigid internal fixation.

Materials and Method

Sixty-eight cases of condylar fractures reporting to Vydehi Institute of Dental Sciences, Bangalore, between 2009 and 2018 were reviewed in terms of age, sex, type of fracture, position of the mandibular third molar and the treatment rendered.

Results

The majority of the patients were males (60). There was an involvement of the right side in 34, left in 21 and bilateral involvement in 13 cases. Forty-three of the fractures were subcondylar, and 25 were intracapsular. Significantly in most cases, the mandibular third molar was either fully erupted (42) or missing (12). Sixty-one cases were subjected to surgical management including 49 cases of rigid internal fixation, and 12 of the intracapsular fractures had the condylar stump/segment removed. Only seven cases were not treated surgically. Most of the cases (44) were in the age group of 21-40, 12 were in the age group of 41-60, 9 were in the age group of 1-20, and 3 patients were above 60.

Conclusion

Condylar fractures more often do not require surgical intervention, and their incidence is more likely to occur when the third molar is either fully erupted or missing.

Evaluation of Stress Distribution of Four Different Fixation Systems at High- and Low-Level Subcondylar Fractures on a Nonhomogenous Finite Element Model

PURPOSE

The aim of the present study was to provide insight into a suitable fixation system for subcondylar fractures located at different levels.

MATERIALS AND METHODS

High and low subcondylar fractures were simulated on a nonhomogenous mandibular model, and rhombic, trapezoid, and lambda plates and 2 miniplates were used for fixation. The stress in the bone and displacement of the fracture site were measured using finite element analysis.

RESULTS

For both high and low subcondylar fractures, the lowest von Mises stress was measured in the rhombic plate system. For high subcondylar fractures, the highest tension in the cortical bone was measured in the trapezoid plate system, and the highest compression was measured in the rhombic plate system. For low subcondylar fractures, the highest tension in the bone was measured in the rhombic system and the highest compression was measured in the trapezoid system. In both high and low subcondylar fracture models, the least displacement amount was measured in the 2-plate system.

CONCLUSIONS

The results of the present study have shown that the rhombic plate system might be the proper choice for high subcondylar fractures and the 2-plate system might provide better results for low subcondylar fractures.

Open Rigid Internal Fixation of Low-Neck Condylar Fractures of the Mandible: Mechanical Comparison of 16 Plate Designs

BACKGROUND

In the literature, no information on plates for low-neck mandibular condylar osteosynthesis can be found, despite the fact that 30 plate designs have already been published. The aim of this study was to compare any dedicated plates for possible use in low-neck condylar fracture osteosynthesis.

METHODS

The force required for 1-mm displacement of the fixed fracture fragments and incidents of screw loosening were recorded on polyurethane mandibles among 16 designs of titanium plates fixed by 6-mm screws in a 2.0 system.

RESULTS

Double-straight plate fixation was the mechanical gold standard (15.2 ± 3.5 N), followed by A-shape Condylar Plates (14.9 ± 2.1 N), X-shape Condylar Plates (14.2 ± 1.3 N) and Auto Repositioning Plates (11.8 ± 2.4 N). Screw loosening was uncommon, as a minimum of three screws were placed into the condylar part. Fewer screws were lost from the ramus part of the fixation if the plate was attached to the condylar part by three screws. Often, the stability of the ramus screws was lost when there were only two fixing screws in the condyle (p < 0.001).

CONCLUSIONS

It is advisable to consider the mechanical advantages as one decides which plate to choose for open rigid internal fixation in low-neck condylar fractures, or to only be aware of the significant differences in mobility within the fracture line after fixation with different dedicated plates.

Mechanical Evaluation of Titanium Plates for Osteoesynthesis High Neck Condylar Fracture of Mandible

Background: In the literature no information about plates for the high-neck mandibular condylar osteosynthesis could be found despite that 30 plate designs have been published. The main course consider the basal condylar or diacapitular fractures. The aim of the study was to test mechanically all available designs (only 4 of 30 was proper) on polyurethane mandibles using an individually designed clamping system. Methods: Forces required for a 1 mm displacement of fixed fracture fragments and incidents of screw loosening were recorded. Results: It has occured that dedicated plates for fixation are much weaker than set of two straight plates (p < 0.0001). General observation is the bigger plate and more screws, the better rigid stable osteosynthesis of mandibular condyle, however, there are limitations in plates design for high-neck fractures resulted in restricted operation field. Conclusion: Double straight plates occured to be the best mechanical fixation for high-neck fractures of the mandibular condyle. Maybe other existing plates could be used but only after prebending or that fracture required novel dedicated plates design.

Comparison of Titanium and Bioresorbable Plates in "A" Shape Plate Properties-Finite Element Analysis

(1) Background: The main disadvantage of rigid fracture fixation is remain material after healing period. Implementation of resorbable plates prevents issues resulting from left plates. The aim of this study is to compare the usage of bioresorbable and titanium “A” shape condyle plate in condylar fractures. (2) Methods: Thickness of 1.0 mm, height of 31 mm, and width of 19 mm polylactic acid (PLLA) and titanium “A” shape plate with 2.0 mm-wide connecting bar and 9 holes were tested with finite element analysis in high right condylar neck fracture. (3) Results: On bone surface the highest stress is on the anterior bridge around first hole (approx. 100 MPa). The highest stress on screws is located in the first screw around plate in the anterior bridge and is greater in titanium (150 MPa) than PLLA (114 MPa). (4) Conclusion: Pressure on bone in PLLA osteosynthesis is two times higher than in titanium fixation. On small areas where pressure on bone is too high it causes local bone degradation around the fracture and may delay the healing process or make it impossible. Fixation by PLLA is such flexible that bone edges slide and twist what may lead to degradation of callus.

Which fixation methods are better between three-dimensional anatomical plate and two miniplates for the mandibular subcondylar fracture open treatment?

PURPOSE

To compare the clinical outcomes of a single three-dimensional (3-D) anatomical plate versus two conventional straight miniplates for the open treatment of mandibular subcondylar fractures.

METHODS

This retrospective clinical study included patients with mandibular subcondylar fractures treated by the retromandibular transparotid approach using a 3-D plate or two straight miniplates. Outcome variables included preoperative conditions of patients and fractures, extent of postoperative bone healing, and incidence of complications. Other variables included age, sex, fracture site, and follow-up duration. Variables were evaluated using descriptive statistics and compared between groups.

RESULTS

Twenty-eight fractures were analyzed: 13 fractures using 3-D plate and 15 fractures using two straight miniplates. None of the assessed variables showed significant differences between the two groups (p < 0.05). Unfortunately, in the 3-D plate group, reoperation was necessary for nonunion owing to plate breakage in one case with a bone defect around the fracture.

CONCLUSION

The 3-D plate and two straight miniplates were equally effective for the surgical management of mandibular subcondylar fractures. Although a 3-D plate is sufficient for a typical simple fracture, in cases with a bone defect around the fracture, selection of the plate fixation method should be carefully considered.

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.

METHODS

A three-dimensional intact edentulous mandibular bone (Model I) and a reconstructed mandible bone with fibular graft were created from CBCT images. Calculation models were generated with fibular bone graft extracted from the reconstructed mandible of identical length placed into a mimicked defect area on the right-hand side of the mandible at three different vertical positions: superior (Model II), intermediate (Model III), and inferior (Model IV). Forces were applied at lower left first molar region and lower left central incisor area. Von Mises stresses and mandibular displacement were calculated as outcome measurements during loadings.

RESULTS

Maximum stress and strain within the reconstructed mandible were identified at the posterior border of the graft and the contralateral condyle. Maximum displacement occurred near the interface of fibular graft and anterior segment of the mandible. Stress distribution in the graft under functional loads is much higher than that in the residual mandibular segments from Models II to IV. The combined average maximum stress from anterior and posterior loads is 10.66 times higher in the mandible with inferiorly positioned graft (Model IV), 8.72 times for superior graft (Model II), and 3.68 times for intermediate graft (Model III) than that in the control group (Model I). The worst displacement result during functional loadings was in the group with fibular graft located at the inferior border of the mandible.

CONCLUSIONS

The position of fibular graft placed in the surgical resection site has significant effects on the mechanical behavior of the reconstructed mandible. The fibular graft aligned with the inferior border of the mandible, the most common site designated location by clinicians, has the worst effects on the stress distribution and displacement to the mandibular under functional loads. The fibular graft placed at the intermediate location has the best biomechanics and provides favorable condition for subsequent prosthetic reconstruction.

Does lag screw fixation of condylar fractures result in adequate stability? A finite element analysis

The great incidence and controversies related to the diagnosis, treatment, surgical accesses, and type of osteosynthesis materials confer an outstanding role to condylar fractures among facial fractures. Plate configurations, with diverse formats and sizes, may be used to surgically resolve condylar fractures. With the purpose of improving the advantages and minimizing the disadvantages of fixation techniques, the neck screw was developed aiming at the needed stabilization to render a correct fixation through a system of dynamic compression. This is achieved by increasing the contact between the fractured bone stumps, as well as assisting at the time of fracture reduction. The present paper aims at comparing the fixation and stability of mandibular condylar fractures using the neck screw and an overlaid "L"-shaped-4-hole-2 mm plate on the one hand, with a system in which the neck screw and the "L"-shaped plate form a single structure, having been joined by a welded point, on the other hand. The results with the neck screw are satisfactory, and, thus, it is an alternative for the reduction and fixation of fractures of the mandibular condyle, whether or not a plate is joined to the structure, provided it is correctly prescribed and with adequate surgical sequence and technique.

Surgical Management of Double/Triple Mandibular Fractures Involving the Condylar Segment: Our Perspective

A series of surgical cases operated in our unit are considered to analyze and evaluate the different techniques and sequencing employed in the surgical management of double/triple mandibular fractures involving a condylar fracture. Deviating from the normal sequence of reducing and fixing the dentate segment first, we addressed the condylar segment first. A combination of different approaches for different cases such as a periangular with a vestibular, a preauricular and a retromandibular with a vestibular were used according to the type of fractures. The accessibility to one difficult case with a medially displaced condyle was facilitated by using Hegar's uterine dilators. In all cases, good anatomical reduction was achieved with stable occlusion and without any signs of facial nerve impairment. The 'Condyle first' approach in the surgical management of double/triple mandibular fractures, is a reliable and efficient technique.

Resistance of four fixation techniques used to treat subcondylar fractures

OBJECTIVE

This study aimed to evaluate the resistance of four fixation techniques used to treat subcondylar fractures. The following techniques were evaluated: fixation with one 4-hole single straight plate; fixation with one 2-mm 4-hole system plate and one 1.5-mm 3-hole system plate; fixation with two 2-mm plates with a 3-hole anterior plate; and fixation with two 2-mm plates with four holes each.

STUDY DESIGN

Each fixation technique was subjected to a resistance test. The load values were measured when displacement of 1, 2, and 5 mm was reached. Load values were compared for statistically significant differences using analysis of variance (ANOVA; p < 0.5) and Tukey's test.

RESULTS

Statistically significant differences were observed, when the load was applied to the first molar on the side of the fracture. The group treated with a 4-hole, 2-mm, one plate system showed resistance to lower load values than the groups treated with two plates in any combination.

CONCLUSIONS

When the fracture was fixed using two plates, regardless of the kind of plates used, no statistically significant difference between the groups was observed. However, two plate systems showed better resistance than one plate systems.

Evaluation of an experimental oblique plate for osteosynthesis of mandibular condyle fractures

OBJECTIVE

The aim of this study was to test the bone thickness and potential screw length for osteosynthesis of condylar base fractures (according to the Loukota classification) with an experimental titanium plate, placed in an ideal position against 2 types of conventional plates.

STUDY DESIGN

After exclusion of completely edentulous mandibles, 28 dentate macerated mandibles available at the time of the study were included. Linear regression models 1 and 2 compared the sums of the 2 cranial bone thicknesses and the 3 caudal thicknesses among the 3 different plate designs, and linear models 3 and 4 tested the bone thickness in the 2 most cranial screw axes.

RESULTS

Linear models 1 and 2 revealed significantly higher potential screw lengths for the experimental oblique plate. Equally, linear models 3 and 4 indicated significantly higher bone thickness for the novel oblique plate.

CONCLUSION

The novel proposed oblique plate allows for favorable plate positioning in a biomechanically ideal location with sufficient amounts of local bone for stable plate fixation. When plates with 15-degree angulated screw holes are used, stable bicortical plate fixation can be achieved.

Finite Element Evaluation of Stable Fixation in Combined Mandibular Fractures

PURPOSE

The fixation of combined mandibular fractures, especially symphyseal-condylar fractures, although occurring commonly and having a higher complication rate in the clinic, is rarely investigated regarding predictable therapeutic approaches. Thus this study's aim was to assess different forms of condylar fixation when combined with symphyseal fracture fixation.

MATERIALS AND METHODS

Using finite element models, we analyzed the stress distribution that occurs when a condylar fracture is fixed with 1 miniplate, 2 miniplates, or a trapezoidal condylar miniplate and when a symphyseal fracture is fixed with 2 parallel plates, 2 perpendicular plates, or 2 lag screws. The null hypothesis was that there would be no differences among the different fixation techniques.

RESULTS

The results showed a stress concentration in the anterior region of the condyle, close to the sigmoid notch. Moreover, adequate fixation in the symphysis could result in less tension at the condylar region. Therefore, when the symphysis was fixed with a lag-screw technique, condylar fixation was less required, showing a more adequate stress distribution when the condyle was fixed with 1 or 2 plates. Conversely, when the symphyseal fixation was less effective, by use of perpendicular plates, there was a change in the stress distribution at the condylar region, altering fixation behavior and resulting in more tension and displacement in the condyle, especially when a trapezoidal plate was used.

CONCLUSIONS

A lag screw and parallel double plates appear to be suitable for symphyseal fixation, whereas 2 straightly positioned plates and a trapezoidal plate are suitable for condylar fixation. However, the combination of perpendicular plates in symphyseal fixation and a trapezoidal plate in condylar fixation showed an altered stress distribution.

Comparison of Different Fixation Types Used in Unilateral Mandibular Condylar Fractures: An In Vivo Study With New Biomechanical Model

INTRODUCTION

The aim of this in vivo study is to compare the single-titanium, double-titanium mini plate, and single resorbable plate systems used in internal rigid fixation of the unilateral mandibular condylar fractures on new design biomechanical model.

METHODS

Thirty synthetic polyurethane models were used for biomechanical testing. Fracture lines were created for each model. Fragments were fixed with single-titanium plates in Group A (n = 10), double-titanium plates in Group B (n = 10), and single biodegradable plate (PPLA) in Group C (n = 10). Masticatory forces were applied to the models and the biomechanical properties of the titanium plate and screws, resorbable plate, and screws were evaluated.

RESULTS

The average failure force for Group A, Group B, and Group C is 199, 324, 177N and the average bone displacement for Group A, Group B, Group C is 1.9, 0.3, 2.1 mm, respectively.

DISCUSSION

Double titanium plates showed the most acceptable results in the fixation of unilateral subcondylar fractures where the single titanium and biodegradable plate systems failed to provide enough stability in unilateral subcondylar fracture fixation. Biodegradable plate systems are still not an alternative in fixation of unilateral condylar fractures.