Biomechanical evaluation of a new design titanium miniplate for the treatment of mandibular angle fractures

Comparison of bite force evaluation for mandibular angle fracture fixation by conventional miniplates versus new design miniplates: a clinical study

PURPOSE

To evaluate postoperative masticatory efficacy of a new design non-compression titanium miniplate compared to conventional non-compression titanium miniplate on the basis of bite force for treatment of mandibular angle fractures.

METHODOLOGY

The prospective study included 20 patients with mandibular angle fractures randomly categorized into 2 groups: Group I, fixation of angle fractures by conventional miniplates, and Group II, fixation of angle fractures by new design miniplates. Evaluation was done for clinical outcome, primarily bite force; radiological outcome; and associated postoperative morbidities at different time intervals.

RESULTS

The results showed to be highly significant in terms of mean operating time for plate adaptation and fixation and bite force adaptation (p = 0.003 at follow-up of 6 months) for the newer miniplate compared to the conventional miniplate. No statistically significant difference was seen for postoperative paresthesia, malunion, non-union, occlusal discrepancy, or hardware failure.

CONCLUSION

Within the limits of the study, it appears that the single, monocortical, non-compression, superior border new design miniplate proved to be a successful procedure for treating non-comminuted mandibular angle fractures specifically in terms of enhanced postoperative masticatory efficiency as compared to conventional miniplates. Further clinical studies with larger sample size can derive a more comprehensive conclusion.

Stability and Clinical Outcomes of Angle Fracture Fixation Using Sagittal Split Plate (SSOP) Versus Two Miniplates: Randomized Clinical Trial

The aim of this study was to compare the stability and clinical outcomes between the two miniplates and sagittal split plate (SSOP) in angle fracture fixation. Thirty-eight patients with a mandibular angle fracture were selected and divided randomly into two groups. Intervention was treated with SSOP, and the control group was treated with conventional two miniplates. Clinical evaluation included occlusion, edema, nerve affection, wound dehiscence and mouth opening. Radiographic parameters included the measurement of inter-ramus distance, inter-mental distance and bone density. All clinical parameters were evaluated at one week, one month and three months intervals. Radiographic parameters were evaluated immediately postoperative, and after three months. Results showed that SSOP had less postoperative complications (10.50%) than the two miniplates (31.60%). It can be concluded that both methods offered high performance in management of mandibular angle fractures. However, SSOP group had a significantly shorter operating time, increased bone density and less edema. Clinical trial registration number: NCT03839368.

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.

New design titanium miniplate versus conventional miniplate in treatment of mandibular angle fractures: A comparative study

Introduction

Mandibular angle fracture (MAF) is the second most common site of all fractures of the mandible with the highest complication rate. Management of MAF has evolved in the past four decades. The purpose of the prospective study was to compare the efficacy of new design titanium miniplate (NDM) with conventional titanium miniplate (CTM) in the treatment of MAF.

Objectives

Mouth opening, occlusion, bite force measurement, and radiographs compared preoperatively and first week, first month and third month postoperatively.

Materials and Method

Fourteen patients diagnosed with MAF were randomly divided into two groups: Group A (seven patients) was treated with NDM and Group B (seven patients) with CTM. Patients were assessed preoperatively and postoperatively at an interval of one week, one month and three months.

Results

Repeated measures ANOVA and Post hoc Tukey test showed a significant increase in bite force and mouth opening for both groups in first and third postoperative months. Unpaired t-test showed slightly better mouth opening in Group B and slightly higher bite force in Group A.

Discussion

Both miniplates fulfilled all the study objectives and equally satisfactory healing was seen at the end of third month. NDM offers better stability, rigidity, and anatomic reduction of the fracture with a drawback of difficulty in adaptation and increased operative timing compared to CTM. Hence, we would like to conclude that both miniplates are equally efficient in the treatment of non-comminuted angle fractures with the NDM having upper hand in stability.

Management of Mandibular Angle Fractures Using Single Y-Shaped Titanium Miniplate at the Superior Border: A Prospective Clinical Study

Treatment of angle fractures remains controversial. The various techniques documented for the treatment are: wire osteosynthesis, one miniplate at superior border (2.0 mm), a single plate on inferior border (2.3 or 2.7 mm) along with tension band in the form of arch bar at the upper border, 2 miniplates (1 at superior border and 1 at inferior border), 3-D strut plates or lag screw. To evaluate the efficacy of single Y-shaped titanium miniplate at the superior border in the management of mandibular angle fractures. Total of 15 healthy adult patients reporting to the department of Oral and Maxillofacial Surgery for the treatment of mandibular angle fractures was randomly selected. All the cases were assessed clinically at 1st post-operative day, 1st, 3rd, 6th and 12th week post-operatively for pain, status of occlusion, neurosensory deficit and postoperative hard & soft tissue healing. Radiographic assessment was also done at 1st postoperative day, 6 weeks and 12 weeks. Postoperative pain, infection, wound dehiscence, neurosensory deficit were not evident during the follow- up periods. Radiographically, the fracture reduction was good and plate fracture was not seen in any case. Y- shaped titanium miniplate is an effective method in the management of the mandibular angle fractures and provided satisfactory results.

Macaca mulatta is a good model for human mandibular fixation research

Biomechanical and clinical studies have yet to converge on the optimal fixation technique for angle fractures, one of the most common and controversial fractures in terms of fixation approach. Prior pre-clinical studies have used a variety of animal models and shown abnormal strain environments exacerbated by less rigid (single-plate) Champy fixation and chewing on the side opposite the fracture (contralateral chewing). However, morphological differences between species warrant further investigation to ensure that these findings are translational. Here we present the first study to use realistically loaded finite-element models to compare the biomechanical behaviour of human and macaque mandibles pre- and post-fracture and fixation. Our results reveal only small differences in deformation and strain regimes between human and macaque mandibles. In the human model, more rigid biplanar fixation better approximated physiologically healthy global bone strains and moments around the mandible, and also resulted in less interfragmentary strain than less rigid Champy fixation. Contralateral chewing exacerbated deviations in strain, moments and interfragmentary strain, especially under Champy fixation. Our pre- and post-fracture fixation findings are congruent with those from macaques, confirming that rhesus macaques are excellent animal models for biomedical research into mandibular fixation. Furthermore, these findings strengthen the case for rigid biplanar fixation over less rigid one-plate fixation in the treatment of isolated mandibular angle fractures.

Ag-Incorporated Polydopamine/Tannic Acid Coating on Titanium With Enhanced Cytocompatible and Antibacterial Properties

Titanium (Ti) and its alloys are the most commonly used materials for bone implants. However, implant failure often happens due to bacterial infection. Developing antibacterial coatings on Ti implants is an effective strategy. Dopamine and tannic acid were cross-linked to form coating on Ti through Michael addition and Schiff base reaction. In addition, the Ag ions were grafted on the coating by the redox reaction of phenolic hydroxyl groups. Thus, an Ag-incorporated polydopamine/tannic acid coating was prepared on Ti substrate. SEM, EDS, water contact angle, FTIR, and XRD results demonstrated that the coating was formed on Ti successfully. The antibacterial activity of the coating against Gram-negative E. coli was examined, and the cytotoxicity of the coating was investigated by mouse fibroblast cells. The improvement of hydrophilicity, good cytocompatibility, and antibacterial effectiveness indicates that the coating has potential to surface modification of Ti implants.

Improving mandibular reconstruction by using topology optimization, patient specific design and additive manufacturing?-A biomechanical comparison against miniplates on human specimen

In this study, topology optimized, patient specific osteosynthesis plates (TOPOS-implants) are evaluated for the mandibular reconstruction using fibula segments. These shape optimized implants are compared to a standard treatment with miniplates (thickness: 1.0 mm, titanium grade 4) in biomechanical testing using human cadaveric specimen. Mandible and fibula of 21 body donors were used. Geometrical models were created based on automated segmentation of CT-scans of all specimens. All reconstructions, including cutting guides for osteotomy as well as TOPOS-implants, were planned using a custom-made software tool. The TOPOS-implants were produced by electron beam melting (thickness: 1.0 mm, titanium grade 5). The fibula-reconstructed mandibles were tested in static and dynamic testing in a multi-axial test system, which can adapt to the donor anatomy and apply side-specific loads. Static testing was used to confirm mechanical similarity between the reconstruction groups. Force-controlled dynamic testing was performed with a sinusoidal loading between 60 and 240 N (reconstructed side: 30% reduction to consider resected muscles) at 5 Hz for up to 5 · 10⁵ cycles. There was a significant difference between the groups for dynamic testing: All TOPOS-implants stayed intact during all cycles, while miniplate failure occurred after 26.4% of the planned loading (1.32 · 10⁵ ± 1.46 · 10⁵ cycles). Bone fracture occurred in both groups (miniplates: n = 3, TOPOS-implants: n = 2). A correlation between bone failure and cortical bone thickness in mandible angle as well as the number of bicortical screws used was demonstrated. For both groups no screw failure was detected. In conclusion, the topology optimized, patient specific implants showed superior fatigue properties compared to miniplates in mandibular reconstruction. Additionally, the patient specific shape comes with intrinsic guiding properties to support the reconstruction process during surgery. This demonstrates that the combination of additive manufacturing and topology optimization can be beneficial for future maxillofacial surgery.

Green Tea Polyphenols Coupled with a Bioactive Titanium Alloy Surface: In Vitro Characterization of Osteoinductive Behavior through a KUSA A1 Cell Study

A chemically-treated titanium alloy (Ti6Al4V) surface, able to induce hydroxyapatite precipitation from body fluids (inorganic mineralization activity), was functionalized with a polyphenolic extract from green tea (tea polyphenols, TPH). Considering that green tea polyphenols have stimulating effects on bone forming cells (biological mineralization), the aim was to test their osteoinductive behavior due to co-operation of inorganic and biological mineralization on mesenchymal stem cells KUSA A1. The functionalized surfaces were characterized by using the Folin⁻Ciocalteu method and X-ray photoelectron spectroscopy to confirm the successful outcome of the functionalization process. Two cell cultures of mesenchymal stem cells, KUSA A1 were performed, with or without osteoinductive factors. The cells and surfaces were characterized for monitoring cell viability and hydroxyapatite production: Fourier Transform Infrared Spectroscopy and Raman spectroscopy analyses showed deposition of hydroxyapatite and collagen due to the cell activity, highlighting differentiation of KUSA A1 into osteoblasts. A higher production of extracellular matrix was highlighted on the functionalized samples by laser microscope and the fluorescence images showed higher viability of cells and greater presence of osteocalcin in these samples. These results highlight the ability of polyphenols to improve cell differentiation and to stimulate biological mineralization, showing that surface functionalization of metal implants could be a promising way to improve osteointegrability.

Bio-Functional Design, Application and Trends in Metallic Biomaterials

Introduction of metals as biomaterials has been known for a long time. In the early development, sufficient strength and suitable mechanical properties were the main considerations for metal implants. With the development of new generations of biomaterials, the concepts of bioactive and biodegradable materials were proposed. Biological function design is very import for metal implants in biomedical applications. Three crucial design criteria are summarized for developing metal implants: (1) mechanical properties that mimic the host tissues; (2) sufficient bioactivities to form bio-bonding between implants and surrounding tissues; and (3) a degradation rate that matches tissue regeneration and biodegradability. This article reviews the development of metal implants and their applications in biomedical engineering. Development trends and future perspectives of metallic biomaterials are also discussed.

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.

Finite-Element Analysis of a New Designed Miniplate which is Used via Intraoral Approach to the Mandible Angle Fracture: Comparison of the Different Fixation Techniques

The mandible is the largest facial bone as well as the most commonly fractured bone in the maxillofacial region. Despite numerous studies conducted to identify optimal treatment modalities and plates configurations for intraoral and transoral approaches, no definitive conclusion has been reached. This study used finite element analysis (FEA) to assess 4 scenarios for treatment of an angle fracture (6-hole noncompression miniplate; 6-hole single plate/Champy's technique, 3D strut plate; 2 parallel 4-hole noncompression miniplates). Analysis included segmental displacement and Von Mises Stress evaluations of a 3D reconstruction of a human mandible. Von Mises Stress values for plates did not vary significantly among treatment groups. Moreover, no significant differences were observed in cumulative displacement of segments subjected to vertical and horizontal loads, with all treatment configurations demonstrating clinical acceptability.