The development of plate osteosynthesis for the treatment of fractures of the mandibular body – A literature review

Development of a test bench for biomechanical simulation-a preliminary study of mandibular forces

Purpose: The aim of this study is to develop a test bench, which integrates different complexity levels and enables in that way a flexible and dynamic testing for mid and long term intervals as well as testing of maximum loads till implant failure of different osteosynthesis systems on the mandible. Material and Methods: For this purpose, an analysis of the state of the art regarding existing test benches was combined with interviews of clinical experts to acquire a list of requirements. Based on these requirements a design for a modular test bench was developed. During the implementation of the test stand, functional tests were continuously carried out and improvements made. Depending on the level of complexity, the test bench can be used either as an incorporated variant or as a standalone solution. In order to verify the performance and the degree of fulfilment of the requirements of these two variants of the test bench, preliminary studies were carried out for all levels of complexity. In these preliminary studies, commercially available osteosynthesis and reconstruction plates were investigated for their biomechanical behaviour and compared with data from the literature. Results: In total, fourteen test runs were performed for the different levels of complexity. Firstly, five test runs were executed to test the simplified load scenario in the incorporated variant of the test bench. High forces could be transmitted without failure of the miniplates. Secondly a quasi-static test scenario was examined using the incorporated variant with simplified load insertion. Five experiments with a number of cycles between 40,896 and 100,000 cycles were carried out. In one case the quasi-static testing resulted in a fracture of the tested reconstruction plate with a failure mode similar to the clinical observations of failure. The last four test runs were carried out using the standalone variant of the test bench simulating complex load patterns via the insertion of forces through imitated muscles. During the test runs joint forces were measured and the amplitude and vector of the resulting joint forces were calculated for both temporomandibular joints. Differences in the force transmission depending on the implant system in comparison to the zero sample could be observed. Conclusion: The presented modular test bench showed to be applicable for examination of the biomechanical behavior of the mandible. It is characterized by the adjustability of the complexity regarding the load patterns and enables the subsequent integration of further sensor technologies. Follow-up studies are necessary to further qualify and optimize the test bench.

Comparative evaluation of different osteosynthesis modalities with respect to lingual splaying in mandibular interforaminal fractures using CBCT: A prospective study

Introduction

The management of interforaminal fracture can prove to be challenging because of its unique anatomy and muscular forces. Often, lingual splaying has been found either postoperatively or even during the procedures in such fractures and can be challenging when it comes to managing them. Various modalities such as miniplates, lag screws, and three-dimensional (3D) miniplates have been utilized to manage these fractures. This article compares these three modalities in the management of lingual splaying.

Material and Methods

Thirty patients were allotted randomly to either of the aforementioned modalities randomly in this prospective study. The patients were operated and followed up for the period of 6 months.

Results

It was found that no significant difference exists between the modalities in terms of reduction in lingual splay.

Conclusion

All three modalities have different ventures to offer. A larger sample size study may be warranted to elucidate the obtained results.

Patient-specific plates for facial fracture surgery: A retrospective case series

OBJECTIVES

Surgeons often encounter challenges when treating maxillofacial fractures using conventional methods that involve trimming or bending ready-made titanium plates for open reduction and internal fixation (ORIF) since it can be time-consuming, imprecise, and inconvenient. This retrospective case series aimed to introduce a novel bone reduction method that utilizes virtual planning, patient-specific surgical guides, and titanium plates.

METHODS

Seven patients with mandibular symphysis or subcondylar fractures resulting from facial trauma underwent cone-beam computed tomography (CBCT) or facial CT scans, and their medical histories were documented. Virtual surgery was conducted based on three-dimensional (3D) stereolithography images derived from CT scans using the FaceGide software (MegaGen, Daegu, Korea). ORIF was performed using patient-specific surgical guides and plates that were designed, printed, and milled. Radiographic, clinical, and occlusal evaluations were conducted at two weeks and six weeks postoperatively. Subsequently, 3D images from virtual surgery and postoperative CT scans were compared.

RESULTS

The comparison of 3D virtual surgery and postoperative images revealed minimal surface differences of less than 1 mm. T-scan evaluations indicated that there were no statistically significant differences between the two- and six-week postoperative assessments. Favorable clinical outcomes were observed.

CONCLUSION

This novel method demonstrated stable outcomes in terms of occlusion and healing, with no notable complications. Consequently, this approach may serve as a viable alternative to conventional methods.

CLINICAL SIGNIFICANCE

Facial fracture surgery that utilizes patient-specific surgical guides and plates within a digital workflow can facilitate meticulous surgical planning, reducing the risk of complications and minimizing operation time.

Current Trends in Head and Neck Trauma

The practicing otolaryngologist frequently encounters consultation for injuries in the head and neck. Restoration of form and function is essential to normal activities of daily living and quality of life. This discussion intends to provide the reader with an up-to-date discussion of various evidence-based practice trends related to head and neck trauma. The discussion focuses on the acute management of trauma with minor emphasis on secondary management of injuries. Specific injuries related to the craniomaxillofacial skeleton, laryngotracheal complex, vascularity, and soft tissues are explored.

The Effectiveness of Three-Dimensional Osteosynthesis Plates versus Conventional Plates for the Treatment of Skeletal Fractures: A Systematic Review and Meta-Analysis

PURPOSE

To assess the difference between preformed anatomically shaped osteosynthesis plates and patient-specific implants versus conventional flat plates for the treatment of skeletal fractures in terms of anatomical reduction, operation time, approach, patient outcomes, and complications.

MATERIAL AND METHODS

MEDLINE (1950 to February 2023), EMBASE (1966 to February 2023), and the Cochrane Central Register of Controlled Trials (inception to February 2023) databases were searched. Eligible studies were randomised clinical trials, prospective controlled clinical trials, and prospective and retrospective cohort studies (n ≥ 10). Inclusion criteria were studies reporting the outcomes of preformed anatomically shaped osteosynthesis plates and patient-specific implants versus conventional flat plates after treating skeletal fractures. Outcome measures included anatomical reduction, stability, operation time, hospitalisation days, patients' outcomes, and complications. Two independent reviewers assessed the abstracts and analysed the complete texts and methodologies of the included studies.

RESULTS

In total, 21 out of the 5181 primarily selected articles matched the inclusion criteria. A meta-analysis revealed a significant difference in operation time in favour of the preformed anatomical plates and patient-specific implants versus conventional plates. Significant differences in operation time were found for the orbital (95% CI: -50.70-7.49, p = 0.008), upper limb (95% CI: -17.91-6.13, p < 0.0001), and lower limb extremity groups (95% CI: -20.40-15.11, p < 0.00001). The mean difference in the rate of anatomical reduction in the lower limb extremity group (95% CI: 1.04-7.62, p = 0.04) was also in favour of using preformed anatomical plates and patient-specific implants versus conventional plates.

CONCLUSIONS

This systematic review showed a significant mean difference in surgery time favouring the use of preformed anatomical plates and patient-specific implants for orbital, upper, and lower limb extremity fractures. Additionally, preformed anatomical plates and patient-specific implants in the lower limb group result in a significantly higher rate of anatomical reduction versus conventional flat plates.

Immediate and late inflammatory and bone healing response post implantation of self-tapping and self-drilling osteosynthesis screws

The aim of this study was to comparatively analyse osseointegration after the implantation of self-tapping screws (STS) and self-drilling screws (SDS). Thus, 24 four-month-old male Wistar rats, received SDS and STS screws in their left and right tibias, respectively. Sample collection was performed immediately at 0 hours (0h), two, seven, and 21 days after implantation (2d, 7d, 21d). Samples from immediately and 21 days after were analysed by micro computed tomography (MicroCT). All time points were evaluated by histology (Haematoxylin and Eoisin and Goldner's Trichrome) and immunohistochemistry for tartrate-acid resistant phosphatase positive (TRAP+) osteoclasts. MicroCT images revealed an intimate contact between bone and each type of screw at 0h. However, SDS group presented decreased bone volume (BV, mm3) at 21 days in comparison with STS. Both SDS and STS post implantation presented areas of suitable new bone formation surrounding screw threads from seven days, and inflammation decreased from two to 21 days. Also, TRAP+ osteoclasts were mainly identified at seven days in both STS and SDS groups, particularly surrounding areas of pressure, with significant differences between groups. In conclusion, differences in shape and insertion technique for SDS and STS screws did not affect immediate and late inflammatory and bone healing response post implantation in this animal model. Both osteosynthesis screws allowed satisfactory post-surgical outcomes.

One miniplate versus two miniplates in the fixation of mandibular angle fractures. An updated systematic review and meta-analysis

PURPOSE

The aim of this study is to compare the outcomes after using one miniplate fixation in the external oblique ridge versus two miniplate fixation for mandibular angle fractures.

METHODS

A systematic review of MEDLINE (via PubMed), Scopus and Cochrane Library database was performed (last search date: 04 February 2022) according to the PRISMA guidelines. The research question was addressed using the PICO criteria. Only comparative studies between the two techniques were included. Random-effects model meta-analyses were performed.

RESULTS

Seventeen studies, comprising a total of 1667 patients, 846 undergoing one miniplate fixation and 854 undergoing two miniplate fixation for mandibular angle fractures were identified. No statistically significant differences were observed regarding surgical site infection (odds ratio [OR]= 0.94, 95% confidence interval [CI]: [0.69] - [1.28], p = 0.68, I²=0.00%), post-operative malocclusion (OR= 0.97, 95% CI: [0.53] - [1.18], p = 0.25, I²=0.00%), post-operative neurosensory dysfunction (OR= 0.67, 95% CI: [0.37] - [1.22], p = 0.19, I²=73.93%), pseudoarthrosis formation (OR=0.90, 95% CI: [0.58] - [(1.39], p = 0.63, I²=0.00%). Wound dehiscence was marginally less common in the one miniplate group (OR=0.52, 95% CI: [0.28] - [0.98], p = 0.04, I²=54.34%). The probability of scarring formation (OR=0.13, 95% CI: [0.05] - [0.32], p = 0.00, I²=0.00%) and hardware failure (OR=0.36, 95% CI [0.21] - [0.62], p = 0.00, I²=29.33%) were statistically significantly higher in the two miniplates arm.

CONCLUSION

One miniplate fixation and two miniplates fixation of mandibular angle fractures have similar results regarding post operative infection, malocclusion, neurosensory dysfunction and pseudoarthrosis formation while wound dehiscence, hardware failure and scarring seem to be more common when two miniplates are used as a fixation technique.

Analyzing the Fitting of Novel Preformed Osteosynthesis Plates for the Reduction and Fixation of Mandibular Fractures

Purpose: The known preformed osteosynthesis plates for the midface are helpful tools for a precise and fast fixation of repositioned fractures. The purpose of the current study is to analyze the precision of newly developed prototypes of preformed osteosynthesis plates for the mandible. Methods: Four newly designed preformed osteosynthesis plates, generated by a statistical shape model based on 115 CT scans, were virtually analyzed. The used plates were designed for symphyseal, parasymphyseal, angle, and condyle fractures. Each type of plate has three different sizes. For analysis, the shortest distance between the plate and the bone surface was measured, and the sum of the plate-to-bone distances over the whole surface was calculated. Results: A distance between plate and bone of less than 1.5 mm was defined as sufficient fitting. The plate for symphyseal fractures showed good fitting in 90% of the cases for size M, and in 84% for size L. For parasymphyseal fractures, size S fits in 80%, size M in 68%, and size L in 65% of the cases. Angle fractures with their specific plate show good fitting for size S in 53%, size M in 60%, and size L in 47%. The preformed plate for the condyle part fits for size S in 75%, for size M in 85%, and for size L in 74% of the cases. Conclusion: The newly developed mandible plates show sufficient clinical fitting to ensure adequate fracture reduction and fixation.

Biomechanical evaluation of magnesium plates for management of mandibular angle fracture

The aim of this study was to evaluate the efficacy of magnesium plates for the management of fractures of the mandibular angle. Fresh sheep hemimandibles were divided into 7 groups and a biomechanical cantilever bending test was used for the groups: Group 1 included fractured hemimandibles fixed at the angle with a single 1mm magnesium miniplate; Group 2 had fixation with a 1mm double magnesium miniplate; Group 3 used a 2mm thick single magnesium miniplate; Group 4 used double 2mm magnesium plates; Group 5 each had a single 1mm thick titanium plate; Group 6 used 1mm thick double titanium plates; and Group 7 comprised intact hemimandibles. Each group was tested using universal testing machine yield loads; yield displacements and stiffness were compared using one way analysis of variance (ANOVA) Group 1 (1mm single magnesium plate) and Group 2 (1mm double magnesium plates) showed lower stability than other groups, while the 2mm magnesium plate showed stability similar to the corresponding 1mm titanium plate. Pure magnesium has good mechanical properties and when it is designed properly it can be used for the management of mandibular fracture.

Improved in vivo osseointegration and degradation behavior of PEO surface-modified WE43 magnesium plates and screws after 6 and 12 months

Magnesium is a highly promising candidate with respect to its future use as a material for resorbable implants. When magnesium degrades, hydrogen gas is released. High doses of gas emergence are reported to impair osseointegration and may therefore lead to fixation failure. The successful delay and reduction of the degradation rate by applying plasma electrolytic oxidation (PEO) as a post processing surface modification method for magnesium alloy has recently been demonstrated. The aim of this study was thus to compare the degradation behavior of a WE43-based plate system with and without respective PEO surface modification and to further investigate osseointegration, as well as the resulting effects on the surrounding bony tissue of both variants in a miniature pig model. WE43 magnesium screws and plates without (WE43) and with PEO surface modification (WE43-PEO) were implanted in long bones of Göttingen Miniature Pigs. At six and twelve months after surgery, micro-CT and histomorphometric analysis was performed. Residual screw volume (SV/TV; WE43: 28.8 ± 21.1%; WE43-PEO: 62.9 ± 31.0%; p = 0.027) and bone implant contact area (BIC; WE43: 18.1 ± 21.7%; WE43-PEO: 51.6 ± 27.7%; p = 0.015) were increased after six months among the PEO-modified implants. Also, surrounding bone density within the cortical bone was not affected by surface modification (BVTV; WE43: 76.7 ± 13.1%; WE43-PEO: 73.1 ± 16.2%; p = 0.732). Intramedullar (BV/TV; WE43: 33.2 ± 16.7%; WE43-PEO 18.4 ± 9.0%; p = 0.047) and subperiosteal (bone area; WE43: 2.6 ± 3.4 mm²; WE43-PEO: 6,9 ± 5.2 mm²; p = 0.049) new bone formation was found for both, surface-modified and non-surface-modified groups. After twelve months, no significant differences of SV/TV and BV/TV were found between the two groups. PEO surface modification of WE43 plate systems improved osseointegration and significantly reduced the degradation rate within the first six months in vivo. Osteoconductive and osteogenic stimulation by WE43 magnesium implants led to overall increased bone growth, when prior PEO surface modification was conducted.

Biomechanical Assessment of the Validity of Sheep as a Preclinical Model for Testing Mandibular Fracture Fixation Devices

Mandibular fracture fixation and reconstruction are usually performed using titanium plates and screws, however, there is a need to improve current fixation techniques. Animal models represent an important step for the testing of new designs and materials. However, the validity of those preclinical models in terms of implant biomechanics remains largely unknown. In this study, we investigate the biomechanics of the sheep mandible as a preclinical model for testing the mechanical strength of fixation devices and the biomechanical environment induced on mandibular fractures. We aimed to assess the comparability of the biomechanical conditions in the sheep mandible as a preclinical model for human applications of fracture fixation devices and empower analyses of the effect of such defined mechanical conditions on bone healing outcome. We developed 3D finite element models of the human and sheep mandibles simulating physiological muscular loads and three different clenching tasks (intercuspal, incisal, and unilateral). Furthermore, we simulated fractures in the human mandibular body, sheep mandibular body, and sheep mandibular diastema fixated with clinically used titanium miniplates and screws. We compared, at the power stroke of mastication, the biomechanical environment (1) in the healthy mandibular body and (2) at the fracture sites, and (3) the mechanical solicitation of the implants as well as the mechanical conditions for bone healing in such cases. In the healthy mandibles, the sheep mandibular body showed lower mechanical strains compared to the human mandibular body. In the fractured mandibles, strains within a fracture gap in sheep were generally not comparable to humans, while similar or lower mechanical solicitation of the fixation devices was found between the human mandibular body fracture and the sheep mandibular diastema fracture scenarios. We, therefore, conclude that the mechanical environments of mandibular fractures in humans and sheep differ and our analyses suggest that the sheep mandibular bone should be carefully re-considered as a model system to study the effect of fixation devices on the healing outcome. In our analyses, the sheep mandibular diastema showed similar mechanical conditions for fracture fixation devices to those in humans.

Locking versus non-locking plating system in the treatment of mandibular fractures: A randomized comparative study

To evaluate fracture stability and complications such as infections, need for hardware removal, malunion, and nonunion when using 2.0-mm locking plating system in fixation of mandible fractures and to compare these to those associated with the 2.0-mm non-locking plating system. A prospective clinical study was conducted in a cohort of mandible fracture patients who were randomly assigned to two groups. Patients in the non-locking group were treated with 2.0-mm non-locking plating system, and those in locking group were treated with 2.0-mm locking plating system. Fracture stability, need for maxillomandibular fixation (MMF) and postoperative complications were assessed and compared. A total of 60 patients (30 in each group) were recruited. Significant differences were found between the two groups with respect to postoperative fracture stability (P = 0.001) and need for MMF (P = 0.005). Multivariate analysis revealed that type of fixation was not the only dependent variable which affected fracture stability. There were no significant differences in postoperative complications between the two groups. The 2.0-mm locking plating system provides greater stability and early functional restoration than the 2.0-mm non-locking plating system, with similar rates of postoperative complications. Thus, it can be used as a reliable and effective treatment modality for treating mandibular fractures.

Comprehensive analysis on orthopedic drilling: A state-of-the-art review

Bone drilling is a well-known internal fixation procedure to drill a hole, fixing the bone fragments to reduce the susceptibility of permanent paralysis. The success of bone drilling is evaluated based on the extent of osteonecrosis in terms of heat generation, tissue damage, quality of hole, and drilling forces. The appropriate control of cutting conditions, drill geometric parameters, and bone-specific parameters offer bone drilling a viable solution through conventional and non-conventional drilling techniques. The majority of the published research work considers only limited parameters and tries to optimize the drilling parameters and performance measures. However, bone drilling involves numerous conventional and non-conventional drilling parameters and technologies. In order to develop a better understanding of all the studied parameters and performance measures, there is a dire need to develop a framework. The key objective of this review study is to establish a hierarchy of the framework by collecting almost all the parameters studied until now and addressed the relationship between parameters and performance measures to diminish the controversies in the published literature. Therefore, this framework is novel in nature, organizing all the parameters, performance measures, logical comparisons, and limitations of studies. This holistic review can help medical surgeons and design engineers to understand the complicated relationship among parameters and performance measures associated with this state-of-art technologies. Also, modeling, simulations, and optimization techniques are included to explore the application of such techniques in recent advancements in orthopedic drilling.

Donor-site Morbidity after Retromolar Bone Harvesting Using a Standardised Press Fit Cylinder Protocol

Precise fitting and immobilisation of bone transplants at the recipient site is of utmost importance for the healing process. With the help of the standardised Osseo Transfer System, the recipient site is adjusted to the graft, rather than vice versa as it is typically done. The aim of this study was to analyse donor-site morbidity after harvesting cylindrical bone grafts from the retromolar region using the Osseo Transfer System. The patient satisfaction with the surgical procedures was also evaluated. All patients treated with this standardised reconstruction method between 2006 and 2013 at the Department of Cranio-Maxillofacial Surgery, University Hospital Giessen, were included in this study. Complications were recorded and evaluated. Bone graft success and patient satisfaction were documented with a questionnaire, and then confirmed by clinical and radiological follow-up examinations. Fifty-four patients were treated and 64 harvested cylindrical autologous bone grafts were transplanted. In all cases, dental implants could be inserted after bone healing. One patient lost an implant, associated with failure of the bone graft. Six patients who were examined continued to show neurological disorders in locally limited areas. No complete or long-term damage of the inferior alveolar nerve occurred. More than 94% (n = 52) of the patients were 'very satisfied' or 'satisfied' with the results and would recommend this surgical treatment to other patients. The standardised Osseo Transfer was an effective treatment option for small and mid-sized alveolar ridge augmentations. A low donor-site morbidity rate and a high transplant success rate were verified. The Osseo Transfer System demonstrated to be a reliable surgical technique without major complications. We highly recommend this surgical augmentation procedure as a surgical treatment for local bone defects.

The risk of tooth root injuries using cortical screws for intermaxillary fixation and osteosynthesis plates - A retrospective analysis

Intermaxillary fixation (IMF) and osteosynthesis plates (OP) are widely used for the non-surgical and surgical treatment of mandible and condyle fractures. The aim of this retrospective study was to analyze the frequency of tooth root injuries by IMF and OP screws. Electronic patient reports (2004-2013) were screened for patients treated with either IMF screws and/or OP in the Department of Oral- and Maxillofacial Surgery, University Medical Center Mainz, Germany. The frequency and the position of endangered and injured teeth were analyzed by orthopantomogram (OPTG) and cone beam computer tomography (CBCT). Next, possible predictive factors for tooth root injuries, namely interdental- and crestal distance, screw length and distance between tooth root and screw were evaluated. Further, the accuracy of OPTG vs. CBCT concerning the diagnosis of tooth root injuries was analyzed. Three-hundred sixty-six patients were included and 3388 teeth were defined as endangered by IMF- and OP screws. Overall, 16 injured teeth (0.5%) in 13 patients (3.55%) were detected. Nine injuries (56.3%) were caused by IMF- and seven injuries (43.8%) by OP screws. Three teeth were non-vital, one tooth had to be extracted. No correlation between the predictive factors crestal distance, screw length and tooth root injuries was found. If tooth injury occurred, a significant correlation between the interdental distance and the distance between tooth root and screw was found (κ = 0.48; p < 0,0001). Comparison between OPTG vs. CBCT demonstrated that many of the injuries that were seen in the OPTG (n = 230) could not be verified in the CBCT scans (n = 16) (κ = 0.12). To conclude, screws for IMF and OP can be considered as a safe procedure concerning the risk of tooth root injuries.

Locking Miniplate Osteosynthesis of Anterior Mandibular Fractures-Quo Vadis?

PURPOSE

This study compared the clinical stability and efficacy of locking miniplates with those of standard miniplates in the osteosynthesis of anterior mandibular fractures using bite force recordings and other clinical parameters.

MATERIALS AND METHODS

A prospective randomized double-blinded clinical trial was carried out in patients from various hospitals of Hassan (India). Patients were randomly divided into 2 groups of locking (test) and standard (control) miniplate osteosynthesis. Bite force measurements were performed preoperatively and postoperatively at weekly intervals for 6 weeks using a bite force recorder. As a secondary outcome, patients also were assessed for other clinical parameters that might interfere with successful osteosynthesis at the fracture site. Appropriate statistical testing for intra- and intergroup measurements was carried out.

RESULTS

Forty-eight men 28 ± 12.3 years old met the inclusion criteria (24 patients in each group). A statistically significant difference (P < .05) was found in the incisor bite force between the 2 groups, with values in the locking group exceeding those in the standard group at postoperative weeks 2 and 5. Duration of surgery was shorter in the locking group (P = .015). No relevant difference was found for the other clinical parameters.

CONCLUSIONS

Bite force statistically increased at progressive follow-up visits compared with the preoperative recording in the locking group. Bite force recordings of patients treated with locking plates were higher and statistically relevant compared with those of patients treated with standard miniplates at the incisor region at postoperative weeks 2 and 5. The clinical outcomes of the 2 miniplate systems in the present study were similar; however, the locking miniplates required a relatively shorter operating time, produced less trauma to the periosteum and soft tissues with less hardware, and can be used as a "1-plate-for-all" system.

Comparative evaluation of a single 2.0-mm AO locking reconstruction plate with conventional miniplate osteosynthesis for treatment of linear non-comminuted fractures of symphysis and parasymphsis region of the mandible

The objective of the study was to evaluate and compare the relative efficacy of treating linear non-comminuted mandibular fracture of symphysis and parasymphysis region using single 2.0-mm AO locking reconstruction plate or using two conventional miniplates. In this study, 80 patients of symphysis or parasymphysis fracture were divided randomly in two equal groups and treated with open reduction and internal fixation using two 2.5-mm miniplates or with a single 2.0-mm AO locking reconstruction plate. Operating time in case of open reduction and fixation using a single 2.0-mm locking reconstruction plate was significantly less when compared to open reduction and fixation using two conventional miniplates. Both groups showed satisfactory fracture reduction and healing. No postoperative malocclusion was noted, and both groups showed comparable improvement in masticatory efficiency. In conclusion, fracture fixation using a single 2.0-mm AO locking reconstruction plate without use of a second plate at the superior border for treatment of linear non comminuted mandibular fracture in symphysis and parasymphysis region gives comparable results as with treatment by conventional miniplate system and provides significant savings in operating time, ease of use and decrease in amount of hardware incorporated in the body.

Titanium Lag Screw Versus Miniplate Fixation in the Treatment of Anterior Mandibular Fractures

PURPOSE

The use of plates for open reduction and internal fixation of mandibular fractures has become a widely accepted method in the past 3 decades. However, the anterior mandible is well suited to lag screw fixation owing to the thickness of its bony cortices. Hence, the purpose of the present study was to comparatively evaluate clinical outcomes of fixation using lag screws and miniplates in anterior mandibular fractures.

PATIENTS AND METHODS

Fifty patients reporting to the department of oral and maxillofacial surgery with noncomminuted anterior mandibular fractures were randomly divided into 2 groups of 25 patients each. Patients in group A were treated with 2.5-mm lag screws 22 to 26 mm in length and those in group B were treated with 2.0-mm 4-hole miniplates with a gap using monocortical screws. Subsequent follow-up was performed at 3, 6, 12, and 24 weeks postoperatively. The primary determinants included radiographic analysis of the fracture gap and biting efficiency of the patients in groups A and B. The secondary determinants included evaluation of duration of surgery, occlusion before and after injury, and postoperative complications. Results were evaluated using χ² and unpaired t tests.

RESULTS

The mean age of the patients in this study was 29.1 ± 8.32 years (range, 18 to 67 yr). The mean postoperative fracture gap was considerably larger in group B. The mean duration of surgery (minutes) was 37.60 ± 9.30 for group A and 47 ± 6.55 for group B. The difference was statistically significant (P = .001). The lag screw group showed faster improvement in biting efficiency compared with the miniplate group.

CONCLUSIONS

Lag screw fixation was found to have good stability and rigidity, was inexpensive, and was less time consuming in treating anterior mandibular fractures compared with miniplates.

Comparison of a 2.0-mm locking system with conventional 2.0- and 2.4-mm systems in the treatment of mandibular fractures: a randomized controlled trial

PURPOSE

A comparative study of the use of the 2.0-mm locking fixation system with conventional systems in the treatment of mandibular fractures was performed.

METHODS

For this study, 87 consecutive patients with 112 mandibular fractures were randomized to receive either 2.0-mm locking plates (n = 45) or conventional 2.0- or 2.4-mm plates (n = 42) and had a minimum follow-up of 6 months. Fractures were classified based on the degree of displacement and complexity. Statistical analyses were used to verify possible differences between the groups when separately compared unfavourable and favourable cases (p ≤ 0.050).

RESULTS

Despite randomization, systemic diseases were more frequent in the 2.0-mm locking group in favourable cases. Substance abuse occurred predominantly in the 2.0-mm locking group, in unfavourable and favourable fractures. There were more cases of complex fractures in the conventional group in unfavourable cases. One case involving a major postoperative complication occurred in the locking group (2.2%) and three cases occurred in the conventional group (7.1%) but with no significant difference between groups. In this study, there were no major differences between conventional and locking 2.0-mm locking systems with regard to the outcome of treated mandibular fractures, showing that both are adequate as long as the criteria of their indication and requirements for installation are met.

CONCLUSIONS

It was concluded that the 2.0-mm locking fixation system can replace conventional systems in the treatment of mandibular fractures; in addition, this approach was effective in the treatment of unfavourable fractures that typically require the 2.4-mm conventional system.

Self-drilling and self-tapping miniscrews for osteosynthesis fixture after LeFort I osteotomy: An ex vivo trial for primary stability and a randomized clinical study

BACKGROUND

Self-drilling osteosynthesis screws (SDS) have a potential higher primary stability together with clinical advantages such as less time effort compared to self-tapping screws (STS). The aims of the study were to compare the primary stability of SDS and STS ex vivo and to analyze of the time-saving effect in vivo.

MATERIALS AND METHODS

Ex vivo, both screws were placed in porcine bone. Torque was measured for insertion and removal. Four specimens were kept in bone for histologic bone-to-implant-contact examination. In vivo, 49 patients who received orthognathic surgery in the maxilla were included in 2 centers. In a split-mouth design, the time for osteosynthesis fixation and perioperative events were recorded.

RESULTS

Ex vivo, insertion and removal torque measurements were higher for SDS, especially in dense bone. Histologic imaging on the exemplary-stained specimens showed higher bone contact and compressed bone matrix for SDS in all bone densities. In vivo, the mean osteosynthesis time in both centers was 5.5 min (±3.03) for SDS and 5.5 min (±2.37) for STS. Separate analysis showed that center I was faster with STS and center II with SDS. Although, in center I a higher rate of failed primary stability of SDS compared to STS was documented.

CONCLUSIONS

SDS showed a partially higher primary stability ex vivo, especially in dense bone. The timesaving effect of SDS is less pronounced than expected, but technically SDS might be favorable where drilling is difficult or even impossible.

Development of a methacrylate-terminated PLGA copolymer for potential use in craniomaxillofacial fracture plates

We synthesised methacrylate-terminated PLGA (HT-PLGA, 85:15 LA:GA, 169kDa), for potential use as an adhesively attached craniomaxillofacial fracture fixation plate. The in vitro degradation of molecular weight, pH and flexural modulus were measured over 6weeks storage in PBS at 37°C, with commercially available high (225kDa, H-PLGA) and low (116kDa, L-PLGA) molecular weight 85:15 PLGAs used as comparators. Molecular weights of the materials reduced over 6weeks, HT-PLGA by 48%, H-PLGA by 23% and L-PLGA by 81%. HT-PLGA and H-PLGA exhibited a near constant pH (7.35) and had average flexural moduli in excess of 6GPa when produced, similar to that of the mandible. After 1week storage both exhibited a significant reduction in average modulus, however, from weeks 1-6 no further significant changes were observed, the average modulus never dropped significantly below 5.5GPa. In contrast, the L-PLGA caused a pH drop to below 7.3 by week 6 and an average modulus drop to 0.6 from an initial 4.6GPa. Cell culture using rat bone marrow stromal cells, revealed all materials were cytocompatible and exhibited no osteogenic potential. We conclude that our functionalised PLGA retains mechanical properties which are suitable for use in craniofacial fixation plates.

Retrospective Analysis of Surgically Managed Maxillofacial Fractures in Kayseri Training and Research Hospital

Objective

To retrospectively evaluate the clinical and surgical data of patients with maxillofacial fracture (MFF) who were surgically treated at the Department of ENT and Head Neck Surgery in the Kayseri Training and Research Hospital and to compare and discuss the results with relevant literature, including that from Turkey.

Methods

Data concerning the age, gender, etiology, type and site of injury, treatment modality, and postoperative complications were collected and analyzed from medical records of patients who underwent maxillofacial surgery for MFF at the Department of ENT and Head Neck Surgery in the Kayseri Training and Research Hospital between January 2013 and March 2015.

Results

A total of 35 patients were surgically treated because of MFF between January 2013 and March 2015. Of the 35 patients, 28 (80%) were male, whereas seven (20%) were female. Traffic accidents (40%) were the most frequent cause of MFFs. Mandibular fractures (49.1%) were the most common fractures, followed by zygomatic fractures (31.6%). Surgical management of MFFs was performed via closed reduction (17.5%) and/or open reduction with internal fixation by miniplates (82.5%). A total of five complications were observed in the present study: malunion (n=2), removal of fixation plate because of infection (n=2), and permanent infraorbital nerve injury (n=1).

Conclusion

Based on the experience from the close proximity of the area, we think that surgeries for MFFs should be in the surgical repertoire of ENT surgeons.

Assessment of compression and strength of divergent screws mounted on miniplates for fixation of mandibular fractures: an in vitro experimental study

An efficient band of tension is critical for the adequate fixation of mandibular fractures, so fixation devices that compress are helpful. We aimed to evaluate the possibility of creating compression using screws inserted divergently into miniplates placed in the tension zone of mandibular fractures and record the effects on the strength of fixation. For this in vitro experimental study we prepared 20 sheep hemimandibles. After angle fractures had been created, the specimens were divided into standard and study groups (n=10 in each). In the standard group the tension zones were fixed in the standard manner with 4-hole miniplates and 4 parallel screws. Those in the study group were fixed as for the standard group but with 4×45° divergent screws. The differences in the gap in the fracture line before and after fixation were measured as indicators of compression. The strength of fixation was also assessed with a universal testing machine in vitro. The amount of compression was significant only in the study group (p<0.001), and there was no difference in the strength of fixation between the two groups (p=0.7). We conclude that divergent drilling and insertion of screws creates more horizontal force when miniplates are used, and results in reduction in the size of the probable gap in the fracture line. Insertion of divergent screws in miniplates may create compression between fractured segments without jeopardising the strength of fixation.

Study of Efficacy and the Comparison Between 2.0 mm Locking Plating System and 2.0 mm Standard Plating System in Mandibular Fractures

PURPOSE

The purpose of this study was to evaluate the efficacy and comparison between 2.0 mm locking plate system and 2.0 mm Champy's titanium mini plating system in mandible fractures.

MATERIALS AND METHODS

A total of 20 patients with mandibular fractures were selected and divided into two groups A and B on randomized basis. Group A was treated with open reduction internal fixation using 2.0 mm locking plates and group B with 2.0 mm Champy's titanium miniplates. All patients were followed up for 12 weeks postoperatively.

RESULTS

Results of the study show less screw loosening, less precision in plate adaptation and less alteration of the osseous or occlusal relationship upon screw tightening in group A. Chi square test was applied to compare the results between the two groups. Statistical analysis did not show significant difference of incidence of malocclusion between the two groups (p value = 0.606). Statistical analysis using un-paired t test showed significant difference of working time between the two groups (p value = 0.00296). When comparing the overall complication rates according to plates used, the χ(2) test showed no statistically significant difference between the locking and nonlocking plates (p > 0.05).

CONCLUSION

It is observed in our study that the locking plate/screw system offers significant advantages over the conventional plating system. The precise adaptation required for using conventional plates is not needed when this locking plate/screw system is used. Locking plate/screw system provides better stability than the conventional plate/screw system.

Functional and radiologic outcome of open reduction and internal fixation of condylar head and neck fractures using miniplate or microplate system

BACKGROUND

Although the appropriate management of condylar process fractures after miniplate or microplate fixation has been described, there has been no comparative analysis of these plating systems.

METHODS

A retrospective review of patients who underwent open reduction and internal fixation (ORIF) of condylar head or neck fractures at our institution from January 2000 through August 2010 identified 70 patients. Of these, 38 were treated with microplates and 32 with miniplates. The primary functional and radiographic results were the maximal mouth opening and condylar bone resorption, respectively. The rates of complications, including malocclusion, chin deviation, temporomandibular joint complaints, and facial nerve palsy, were recorded.

RESULTS

The maximal mouth opening was larger in the microplate group than in the miniplate group throughout the follow-up period; this difference was statistically significant 12 (P = 0.020), 18 (P = 0.026), and 24 (P = 0.032) months after ORIF. Similarly, the radiographic scores for bone resorption and condyle morphology were significantly better in the microplate group than in the miniplate group throughout the follow-up period [6 (P = 0.011), 12 (P = 0.035), 24 (P = 0.026), and 48 (P = 0.040) months after ORIF]. Moreover, patients who underwent miniplate fixation experienced a significantly higher incidence of temporomandibular joint click than those who underwent microplate fixation (P = 0.014).

CONCLUSIONS

Microplates limit dissection, providing excellent fixation for intracapsular condylar head fractures, and also provide adequate rigidity for fixation of condylar neck fractures. Microplate fixation of condylar head and neck fractures yielded excellent functional and radiographic results. The rates of complications after microplate fixation were equal to or less than those in the miniplate group. Prospective studies are needed to confirm these findings.

Use of a single 2.0-mm locking AO reconstruction titanium plate in linear, non-comminuted, mandible fractures

Purpose:

The aim of the following study is to prospectively evaluate the use of a single Arbeitsgemeinschaft für Osteosynthesefragen (AO) 2.0-mm locking reconstruction plate for linear non-comminuted mandibular fractures without the use of a second plate.

Materials and Methods:

This study consisted of a sample of 10 patients who reported to the department with fractures of the mandible and were treated over a period of 24 months from November 2010 to November 2012. Out of these, there were 8 male patients and 2 female patients. There were four cases of isolated parasymphysis fractures, 1 of the case had a parasymphysis fracture associated with subcondylar fracture, 4 had a body fracture and 2 had a symphysis fracture.

Results:

All patients had satisfactory fracture reduction and a successful treatment outcome without major complications. Only one patient (10%) developed minor complications.

Conclusion:

The study has demonstrated that treating linear non-comminuted mandibular fractures with a single AO 2.0-mm locking reconstruction plate provides excellent stability at the fracture site which in turn leads to sound bone healing and early functional rehabilitation.

Fractographic analysis of 2.0-mm plates with a screw locking system in simulated fractures of the mandibular body

PURPOSE

The purpose of the present study was to analyze the fractured plates from 2 brands of 2.0-mm locking fixation systems submitted to axial linear load testing.

MATERIALS AND METHODS

Four aluminum hemimandibles with linear sectioning to simulate a mandibular body fracture were used as a substrate and fixed with 2 fixation techniques from 2 national brands: Tóride and Traumec. The techniques were as follows: one 4-hole plate, with four 6-mm screws in the tension zone, and one 4-hole plate, with four 10-mm screws in the compression zone; and one 4-hole plate, with four 6-mm holes in the neutral zone. The hemimandibles were submitted to vertical linear load tests using an Instron 4411 mechanical test machine. The system was submitted to the test until complete failure had occurred. Next, a topographic analysis of the surface of the plates was performed using a stereomicroscope and an electronic scanning microscope. The samples were evaluated using different magnifications, and images were obtained.

RESULTS

The surface of the fracture analyzed in scanning electron microscopy demonstrated a ductile-type fracture, usually found in the traction test bodies of ductile materials, such as titanium. No evidence of failure was observed in any fracture surface from a change in the structure or composition of the material.

CONCLUSIONS

The plates were fractured by a ductile rupture mechanism, as expected, suggesting that the manufacturing of the national brand name plates used in the present study has been under adequate quality control, with no structural changes produced by the manufacturing process that could compromise their function.

In vitro mechanical assessment of 2.0-mm system three-dimensional miniplates in anterior mandibular fractures

This study constituted a comparative assessment of the mechanical resistance of square and rectangular 2.0-mm system three-dimensional miniplates as compared to the standard configuration using two straight miniplates. 90 polyurethane replica mandibles were used for the mechanical trials. Groups 1, 2, and 3 simulated complete symphyseal fractures characterized by linear separation of the central incisors; groups 4, 5, and 6 simulated parasymphyseal fractures with an oblique configuration. Groups 1 and 4 represented the standard method with two straight miniplates set parallel to one another. Square miniplates were used in groups 2 and 5, and rectangular miniplates in groups 3 and 6. A universal testing machine set to a velocity of 10mm/min and delivering a vertical linear load to the first left molar was used to test each group. Maximum load values and load values with pre-established dislocation of 5mm were obtained and submitted to statistical analysis using a calculated reliability interval of 95%. The mechanical performances of the devices were similar, except in the case of rectangular plates used in the parasymphyseal fractures. The innovative fixation methods used showed significantly better results in the case of symphyseal fractures.

Locking v/s non-locking reconstruction plates in mandibular reconstruction

Purpose:

To compare the efficacy of locking plates to non-locking plates in the osteosynthesis of mandibular fractures on the basis of clinical parameters.

Materials and Methods:

A prospective randomized clinical trial was conducted at the Faculty of Dental Science, CSMMU (formerly King Georges Medical College), Lucknow, to treat consecutive mandible fractures. The patients were randomly divided into two groups. The patients underwent osteosynthesis—group 1 with 2.4-mm locking titanium plates and group 2 with 2.7 mm non-locking titanium plates. The cause of trauma, the number of days from injury to surgery, average age, gender, and site distribution were all reviewed. The assessment of the patients was done at 1, 3, and 6 weeks and 3 months using the clinical parameters.

Results:

A total of 12 patients with mandibular fractures met the inclusion criteria. In our study, a statistically significant difference was not found in the clinical parameters such as infection, paraesthesia, hardware failure, and mobility between the fracture segments. A statistically significant difference was found between pain and swelling from the previous follow-up visit in groups 1 and 2. In locking group, pain decreases significantly at 3^rd week, 6^th week, 12^th week from 1^st week and pain was absent after 3 week. In non-locking group, pain decreases significantly at 3^rd week, 6^th week and 12^th week from 1^st week but pain was present till 12^th week. Pre-operative swelling was present only in case of non-locking group. Swelling was present in 66.7% of non-locking group and 0% in locking group. After one week swelling was absent in 100% patients at 3^rd, 6^th and 12^th week. Swelling was considerably decreased in locking group as compared to the non-locking group.

Conclusion:

These findings show that the use of locking plates in mandibular fracture was efficacious enough to bear the masticatory loads during osteosynthesis of the fracture. The locking plates provide the advantage of a greater stability, with clinical results almost similar to those seen with non-locking plate osteosynthesis.

Use of intermaxillary forces in early treatment of maxillary deficient class III patients: results of a case series

INTRODUCTION

The early treatment of Class III malocclusion with a protraction facemask can produce forward movement of the maxilla but is generally associated with posterior rotation of the mandible and dentoalveolar compensations. This article shows the dental and skeletal effects of intermaxillary elastics applied to temporary anchorage devices in the treatment of maxillary deficient Class III patients.

MATERIALS AND METHODS

A total of 6 patients with skeletal Class III malocclusion were treated with intermaxillary elastics only. This traction was applied between modified miniplates placed in the maxilla and a modified lower acrylic resin plate bonded on mandibular tooth surfaces. To evaluate the orthodontic changes, lateral cephalograms were taken at the start of the treatment (T1), at the end of the orthopaedic treatment (T2) and at the follow-up (T3).

RESULTS

All patients showed orthopaedic correction of the skeletal Class III relationship with reduction of facial concavity. No dentoalveolar compensations or changes in mandibular position were observed.

CONCLUSION

The treatment of maxillary deficiency with orthopaedic forces from skeletal anchorage directed to the hooks of a modified lower acrylic resin plate bonded on the mandibular tooth surfaces, seems to be a promising technique.

Finite Element Analysis: A Maxillofacial Surgeon's Perspective

The science of finite element analysis (FEA) is purely a mathematical way of solving complex problems in the universe. In medical field, this is an innovation in biomedical research and development, as it gives easier mathematical solution to biological problems. This article deals with the understanding of various basic material properties of bone like Young's modulus, yield strength, Bulk modulus, shear modulus, Poisson's ratio and density from a maxillofacial surgeon's perspective. Basic concepts in FEA, its application, advantages, disadvantages, and limitations in the field of maxillofacial surgery have been discussed. The importance of surgical fraternity to be in coordination with evolving technologies has been emphasized for the future of evidence based practice of oral and maxillofacial surgery.

Comparison of miniplate versus lag-screw osteosynthesis for fractures of the mandibular angle

OBJECTIVES

Treating mandibular angle fractures is common in maxillofacial surgery. The aim of this study was to compare lag screw fixation and miniplates.

STUDY DESIGN

This retrospective investigation compared patients treated with miniplates (n = 24) and with lag screws (n = 21). Inclusion criteria were a solitary angle fracture without comminution or other reasons for load-bearing osteosynthesis. The main parameters for the outcome analysis were fracture gaps at 4 defined measuring points on postoperative radiography. Postsurgical complications were recorded.

RESULTS

Fracture gaps measured in panoramic radiographs differed significantly between the lag-screw (average 0.56 mm) group and the group using 1 miniplate (average 0.85 mm) and 2 miniplates (1.40 mm). Miniplate fixation resulted in a wider fracture gap, especially in the region of the lower margin of the mandible.

CONCLUSION

Lag-screw fixation demonstrated smaller fracture gaps compared with miniplate fixation.

Treatment of linear mandibular fractures using a single 2.0-mm AO locking reconstruction plate: is a second plate necessary?

PURPOSE

To prospectively evaluate the use of a single Arbeitsgemeinschaft für Osteosynthesefragen (AO) 2.0-mm locking reconstruction plate for linear noncomminuted mandibular fractures without the use of a second plate.

PATIENTS AND METHODS

We analyzed the clinical and radiologic data of 45 patients with 74 fractures (21 single fractures, 22 double fractures, and 2 triple fractures). Fracture locations were the symphysis (n = 35, 47.3%), body (n = 15, 20.3%), and angle (n = 24, 32.4%). We recorded the mechanism of injury, time between admission to the hospital and surgery, gender and age, temporary maxillomandibular fixation and its duration, and the surgical approach. Postsurgical complications that were recorded as minor did not require surgical intervention, whereas major complications required further surgical intervention.

RESULTS

All patients had satisfactory fracture reduction and a successful treatment outcome without major complications. Ten patients (22.2%) developed minor complications.

CONCLUSION

The present study has demonstrated that treating linear noncomminuted mandibular fractures with a single AO 2.0-mm locking reconstruction plates is associated with no major complications and sound bone healing in all patients.

Application of a new chair-side method for the harvest of mesenchymal stem cells in a patient with nonunion of a fracture of the atrophic mandible--a case report

PURPOSE

This case report describes a new clinical method for chair-side processing of a cell mixture which contains mesenchymal stem cells (MSCs) which was applied for the first time in the treatment of a nonunion of an atrophic fractured mandible.

METHODS

Bone marrow was aspirated and a corticocancellous bone graft was harvested from the iliac crest of a 56-year-old woman with medical comorbidities and a fracture of the atrophic mandible. The fracture was stabilized with a reconstruction bone plate, and mononuclear cells including MSCs were concentrated by centrifugation and applied in combination with a particulate bone transplant. A sample of the grafted cells was characterized by flow cytometric analysis and by their ability to differentiate into various cell types.

RESULTS

The fracture healed uneventfully. No complications occurred during the 4-month follow-up.

CONCLUSION

Adding MSCs is a feasible alternative to enhance bone healing. This chair-side method requires little training and no cell laboratory support.