The 3-dimensional miniplate is more effective than the standard miniplate for the management of mandibular fractures: a meta-analysis

Assessment of CAD/CAM Customized V Pattern Plate Versus Standard Miniplates Fixation in Mandibular Angle Fracture (Randomized Clinical Trial)

Background

Mandibular angle is the most common site for fractures, accounting for 23-42% of all cases of mandibular fractures. A customized fixation system is designed directly for a specific patient, which reduces the time spent bending and fixing the plate during the operation. This study was designed to assess the effect of CAD/CAM customized V pattern plate versus standard miniplates fixation in mandibular angle fracture.

Materials and Methods

This prospective randomized clinical trial included 26 patients suffering from mandibular angle fracture. Patients were selected from Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Cairo University and Ahmed Maher Teaching Hospital. Study group (13) needed open reduction and internal fixation by using CAD/CAM V plate with surgical guide, while control group (13) needed open reduction and internal fixation by using standard superior-inferior miniplate fixation. The patients were then followed up for one year postoperatively.

Results

It showed that there was a statistical difference between the study group and the control group regarding postoperative pain, occlusion, and maximal interincisal opening (p value < 0.05%). There was no statistical difference (p value > 0.05%) in the postoperative panoramic radiograph that was taken within the postoperative 1st week in both groups, while the increase in mean bone density was statistically significant (p value < 0.05%) from 6 months to one year postoperatively.

Conclusion

CAD/CAM customized V pattern plate is a suitable plate design because it offers sufficient stability for normal bone healing, the creation of an ideal occlusion, an early return to function, and adequate postoperative radiographic outcomes.

Trial Registration

It was registered at ClinicalTrials.gov. Registration number: NCT03761524. Registration date: 03.12.2018.

Resistance and Stress Analysis of 3D Plate and Locking Plate Fixation in Bilateral Sagittal Split Osteotomy: A Comparative Finite Element Study

Aim

This study evaluates the biomechanical properties of 3D plates and compares it with locking plates, in both set back and advancement models of bilateral sagittal split osteotomy (BSSO) using finite element model analysis.

Design

A stereolithography model of mandibular structure was imported to hypermesh to create 3D solid finite model. A BSSO was simulated on hemimandibular model and advancement and setback simulations were carried out for a distance of 4, 6, and 8 mm each. 3D plates for the right side and locking plates for the left side were simulated for fixation. Meshing of the model was carried out. After meshing, the model was imported to Ansys V18.1 for analysis of it. Forces simulating the masticatory muscles were applied on both sides. The values for stress and resistance in the screws and plates were measured and the lowest and highest deformation regions were estimated using von Mises analysis.

Results

The results suggest that the tension and resistance as measured through were better distributed in 3D plates when compared with that of locking plates; the stress concentration was shown to be higher in the locking plates and deformation resistance was greater in 3D plates.

Conclusion

The application of 3D plating system has found its place in the field of maxillofacial trauma. However, its application in the field of orthognathic surgery is yet to be explored and this study encourages us to conduct in vivo studies.

Update on ladder plates for mandibular angle fractures

PURPOSE OF REVIEW

Fractures of the mandibular angle are surgically challenging with high rates of postoperative complications. Among established fixation techniques for these injuries, Champy's tension band approach with miniplate fixation has held prominence. Rigid fixation, using two plates, also remains commonly used. More recently, geometric ladder plates, which confer greater three-dimensional stability have been developed to overcome the shortcomings of conventional fixation approaches. Herein, we aim to summarize the recent evidence surrounding the use of ladder plates and offer our own opinion for optimal treatment of these fractures.

RECENT FINDINGS

In high-powered studies, the rates of hardware failure, malocclusion, and malunion are lower among cohorts managed with ladder plates relative to miniplate groups. Rates of infection and paresthesia remain similar. Ladder plates have also been shown to decrease operative time in preliminary study.

SUMMARY

Ladder plates show superiority to miniplate approaches across several outcomes. However, the relatively larger strut plate constructs may not be necessary for minor, uncomplicated fractures. It is our belief that reasonable outcomes may be achieved with either approach depending on surgeon experience and comfort with the given fixation technique.

Finite element analysis of 3D-printed personalized titanium plates for mandibular angle fracture

This paper discussed the size of 3 D-printed personalized titanium plates that can gain maximum stability of mandibular fracture and minimize stress shielding through finite element analysis. A 3 D virtual model of mandible with mandibular angle fracture was created from the CT data of patient. 3 D-printed personalized titanium plates varying in length and thickness were designed, and finite element analysis was performed under different loading conditions and fracture healing periods. After that, the stress distribution and deformation of the mandible with gonial fracture could be observed, and the stress shielding rate could be obtained. Finally, SPSS21.0 was used for statistical analysis. The results of finite element analysis indicated that as the thickness of titanium plates and the healing time decreased, the maximum displacement increased, under a certain condition in which the pore size, the width, the hole distance and the bridge spacing were 2.0 mm, 4.0 mm, 6.0 mm, 12.0 mm, respectively. What's more, in this condition, the thicker the titanium plate and the shorter the healing time were, the higher the stress shielding was at central occlusion. When the thickness of the personalized 3 D-printed titanium plate was 1.0 mm, the maximum displacement tended to be stable and the stress shielding was minimized. It can not only improve the bone stability after tension band fixation, but also minimize the stress shielding, which is expected to expand the indications of tension band fixation.

Benefit-risk appraisal of lip-split mandibular "swing" vs. transoral approaches to posterior oral/oropharyngeal carcinomas using number needed to treat, to harm, and likelihood to be helped or harmed

PURPOSE

s: To evaluate benefit-risk profiles of lip-split mandibular "swing" vs. transoral approaches (LS-MSA; TOA) to the American Joint Committee on Cancer (AJCC) stage I-III posterior oral/oropharyngeal carcinomas (PO/OPC).

METHODS

Using a retrospective double-cohort study design, we enrolled stage I-III PO/OPC patients treated in two German medical centers during a 4-year interval. The predictor variable was surgical technique (LS-MSA/TOA), and main outcomes were complete resection with R₀ margins (CR-R₀), 5-year overall survival and recurrence (OS₅; R₅), and adverse events (AEs). Descriptive and bivariate statistics were computed with α = 95%. Benefit-risk profiles were investigated using number needed to treat (NNT), to harm (NNH), and likelihood to be helped or harmed (LLH).

RESULTS

At 5-year follow-ups of 202 subjects, LS-MSA caused significantly better CR-R₀ (P = 0.001; NNT: 4) and fewer R₅ (P = 0.003; NNT: 5), but more risks of wound dehiscence ([WD]; P = 0.01; NNH = 8), and orocutaneous fistula ([OCF]; P = 0.01; NNH: 10). LLH calculations demonstrated that LS-MSA was 2 and 1.6 times more likely to result in CR-R₀ and fewer R₅ than an incident of WD. There was no significant difference in OS₅, postoperative infections (within 30 postoperative days) and AE domains according to the University of Washington Quality of Life questionnaire version 4 (UW-QoLv4) between the surgical approach groups.

CONCLUSIONS

Compared to TOA, LS-MSA is an efficacious and tolerable intervention for inspecting and eradicating stage I-III PO/OPCs, and reducing recurrences at 5-year follow-ups. Post-LS-MSA WD and OCF require meticulous concerns and more investigations.

Comparison Between Conventional Titanium Miniplates and Indigenous Detachable Custom made 3D Titanium Plates (VAS 3D Bone Plate) for Fixation of Mandibular Fracture in Mental Foramen Region: A Randomized Clinical Trial and Finite Element Analysis

Purpose

To overcome limitation of 3D plate for fracture fixation in mental foramen region, by designing an indigenous custom made detachable 3D titanium plate (VAS 3D bone plate) and comparing it with two miniplate fixations for fractures of aforementioned region.

Methodology

Finite element analysis (FEA) of VAS plate and randomised clinical trial was performed and compared with miniplates. Twenty fractures in 19 patients with fracture in mental foramen region were divided randomly into two groups (Group I-fixation by miniplates and Group II with VAS plate) and evaluated for ease of fixation, neurosensory deficit, bite forces, occlusion and adequacy of fracture fixation.

Results

FEA of VAS plate revealed better performance for stress distribution, deformation and rigidity. A total of 20 mental foramen region fractures in 19 patients (18 male and 1 female) were treated. Group II had better results for bite forces and lingual control. Except for two patients with screw exposure in Group II and transient neurosensory deficit (resolved by 6 months), no other complications were observed. Ease of fixation was significantly better in miniplate group.

Conclusion

VAS plate was successful in providing satisfactory fixation and was observed to be better in terms of lingual control and masticatory efficiency.

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. Modeling of angle fracture, simulation of muscles of mastication, and defining of boundary conditions were integrated into the theoretical model. Strain levels during different loading conditions were analyzed using a finite element method (FEM). For mechanical test design, samples of the virtual mandible with angle fracture and the custom-designed fixation plates were printed using selective laser sintering (SLS) and selective laser melting (SLM) printing methods. Experimental data were collected from a testing platform with attached strain gauges to the mandible and the plates at different 10 locations during mechanical tests. Simulation of muscle forces and temporomandibular joint conditions were built into the physical models to improve the accuracy of clinical conditions. The experimental vs the theoretical data collected at the 10 locations were compared, and the correlation coefficient was calculated.

RESULTS

The results show that use of the novel-designated fixation plate has significant mechanical advantages compared to the two commonly used fixation plates. The results of measured strains at each location show a very high correlation between the physical model and the virtual mandible of their biomechanical behaviors under simulated occlusal loading conditions when treating angle fracture of the mandible.

CONCLUSIONS

Based on the results from our study, we validate the accuracy of our computational model which allows us to use it for future clinical applications under more sophisticated biomechanical simulations and testing.

Treatment of Mandible Fractures Using a Miniplate System: A Retrospective Analysis

Three-dimensional (3D) mini plate systems are used in the treatment of mandibular fractures. The system is advantageous in comparison to conventional plates due to the stabilization of tension and compression areas, improved initial stability, and biomechanical behavior. The aim of this retrospective study was to evaluate the use of a 3D miniplate system for the treatment of patients with mandibular fractures. Patients with mandibular fractures treated with a 3D plate system at the Department of Oral and Maxillofacial Surgery, University Hospital Münster, during a period of 5 years, were included in this study. Mandibular fracture conditions and minor and major post-operative complications were reported. In total, 336 patients and 391 mandibular fractures were assessed. The most common fracture site was anterior mandible, and 155 cases involved a tooth-bearing area. Minor complications were seen in 8.03% of cases, whereas only 1.49% of patients suffered from major complications. The treatment of mandible fractures using 3D miniplates resulted in fracture reduction with a low complication rate.

A customized fixation plate with novel structure designed by topological optimization for mandibular angle fracture based on finite element analysis

Background

The purpose of this study was to design a customized fixation plate for mandibular angle fracture using topological optimization based on the biomechanical properties of the two conventional fixation systems, and compare the results of stress, strain and displacement distributions calculated by finite element analysis (FEA).

Methods

A three-dimensional (3D) virtual mandible was reconstructed from CT images with a mimic angle fracture and a 1 mm gap between two bone segments, and then a FEA model, including volume mesh with inhomogeneous bone material properties, three loading conditions and constraints (muscles and condyles), was created to design a customized plate using topological optimization method, then the shape of the plate was referenced from the stress concentrated area on an initial part created from thickened bone surface for optimal calculation, and then the plate was formulated as “V” pattern according to dimensions of standard mini-plate finally. To compare the biomechanical behavior of the “V” plate and other conventional mini-plates for angle fracture fixation, two conventional fixation systems were used: type A, one standard mini-plate, and type B, two standard mini-plates, and the stress, strain and displacement distributions within the three fixation systems were compared and discussed.

Results

The stress, strain and displacement distributions to the angle fractured mandible with three different fixation modalities were collected, respectively, and the maximum stress for each model emerged at the mandibular ramus or screw holes. Under the same loading conditions, the maximum stress on the customized fixation system decreased 74.3, 75.6 and 70.6% compared to type A, and 34.9, 34.1, and 39.6% compared to type B. All maximum von Mises stresses of mandible were well below the allowable stress of human bone, as well as maximum principal strain. And the displacement diagram of bony segments indicated the effect of treatment with different fixation systems.

Conclusions

The customized fixation system with topological optimized structure has good biomechanical behavior for mandibular angle fracture because the stress, strain and displacement within the plate could be reduced significantly comparing to conventional “one mini-plate” or “two mini-plates” systems. The design methodology for customized fixation system could be used for other fractures in mandible or other bones to acquire better mechanical behavior of the system and improve stable environment for bone healing. And together with SLM, the customized plate with optimal structure could be designed and fabricated rapidly to satisfy the urgent time requirements for treatment.