Adaptations of the masticatory system after bilateral fractures of the mandibular condylar process

Management of Pediatric Mandibular Condyle Fractures: A Literature Review

This narrative review evaluates the literature on the management of mandibular condyle fractures in growing patients. It aims to illustrate some fundamental biological principles and to offer a series of considerations applicable to clinical practice. The discussion is based on 116 papers published in PubMed and two relevant textbooks. Condylar fractures may be overlooked, especially in pre-scholar children, where compliance is usually reduced. However, these injuries can have disabling sequelae such as ankyloses, facial deformities, malocclusion, and chronic pain in some patients if not diagnosed and managed correctly. Due to their significance, mandibular condyle fractures in children are a subject of considerable clinical interest. As of today, there is consensus about their treatment. Four management options are available: expectative (analgesia, soft food and follow-up), functional protocols (guiding elastics, orthodontic appliances and exercises), maxillomandibular fixation (MMF), and open reduction and internal fixation (ORIF). Nondisplaced and minimally displaced fractures should be treated expectantly; severely displaced non-comminuted fractures can be safely operated on if the expertise is available, even in patients with deciduous dentition. Moderately displaced fractures can be managed with functional protocols or operatively, depending on the background and know-how of the specialist. Functional protocols can achieve good outcomes, especially in patients with deciduous dentition. MMF should be foregone in children due to its many drawbacks.

The effects of treatment timing on the management of patients with multiple facial fractures and on the self-perception of TMD recovery

OBJECTIVE

To investigate the effects of time on the orofacial functions and on the self-perception of temporomandibular disorders (TMD) recovery in a population of patients with multiple facial fractures.

METHODS

Orofacial functions and self-perception of TMD recovery was verified in patients with midface and/or lower face fractures. Patients were divided according to the time between fracture reduction and the clinical assessments: 0-1 month (Group 1), 1-3 months (Group 2), and 15 >3 months (Group 3).

RESULTS

Patients in Group 1 presented a greater compromise of swallowing and mastication when compared to patients with older fractures (p = 0.015), whereas patients in Group 3 presented a poorer TMD recovery (TMJ pain: p = 0.010 and tinnitus: p = 0.004).

CONCLUSION

Delays in functional treatments involving the myofunctional orofacial system have a negative impact on the recovery of essential orofacial functions and on TMD symptoms..

Role of Whey Protein in the Treatment Outcome of Maxillofacial Trauma Patients: An Interventional Study

Introduction

Maxillofacial fracture severely affects the diet of the patients leading to reduction of body weight. Facial trauma affects the muscles of mastication and the bones of face leading to reduction in bite force. The purpose of our study was to investigate the effect of whey protein supplement in the postoperative period of maxillofacial trauma patients with respect to body weight, bite force and callus formation.

Methodology

Patients were divided into control group and study group having 20 patients each. The control group received usual modified diet for maxillofacial fracture and study group received same diet along with whey protein for 6 weeks.

Results

There was mean weight loss of 3.15 kg in control group whereas there was no weight loss of in the study group. There was statistically significant increase in bite force in the study group compared to the control group with p value < 0.05. Early callus formation was seen in study group compared to control group.

Conclusion

Our results showed that patients who were supplemented with whey protein had no loss of body weight, better masticatory efficiency, better healing of the fracture sites and overall early recovery.

Management of Mandibular Condyle Fractures in Pediatric Patients: A Multicentric Retrospective Study with 180 Children and Adolescents

Background: Mandibular condyle fractures in pediatric patients can lead to crippling sequelae such as ankylosis, pain and facial deformity if not managed properly. However, there is no consensus on the best approach for treating these fractures in children. Objective: This study aimed to describe the management of mandibular condyle fractures in growing patients across 14 maxillofacial departments worldwide. Methods: A retrospective multicenter study was conducted on children and adolescents aged 0 to 16 who had at least one mandibular condyle fracture. This study included patients who underwent expectant, closed, or open management and were treated over an 11-year period. Results: 180 patients had at least one mandibular condyle fracture, and 37 had a second condylar fracture. One hundred sixteen patients (65%) were males, and 64 (35%) were females (ratio 1.8:1). An expectant strategy was chosen in 51 (28%) patients, a closed treatment-stand-alone maxillomandibular fixation (MMF)-in 47 (26%), and open reduction and internal fixation (ORIF) was performed in 82 (46%) patients. The management varied significantly between the different departments (p < 0.0001). Significant differences were also identified between the fracture type (non-displaced, displaced or comminuted) and the management of the 180 patients with a single condylar fracture. Out of 50 non-displaced fractures, only 3 (6%) had ORIF, 25 (50%) had expectant management, and 22 (44%) had MMF. Out of 129 displaced fractures, 79 (62%) had ORIF, 25 (19%) had a soft diet, and 25 (19%) had MMF. Conclusions: Expectative management, MMF, and ORIF were all effective in treating pediatric mandibular condyle fractures, with a low incidence of complications and asymmetry.

Analysis of Mandibular Muscle Variations Following Condylar Fractures: A Systematic Review

This review analyzes muscle activity following mandibular condylar fracture (CF), with a focus on understanding the changes in masticatory muscles and temporomandibular joint (TMJ) functioning.

MATERIALS AND METHODS

The review was conducted following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. A search was performed on online databases using the keywords "masticatory muscles" AND ("mandibular fracture" OR "condylar fracture"). The eligibility criteria included clinical trials involving human intervention and focusing on muscle activity following a condylar fracture.

RESULTS

A total of 13 relevant studies were reviewed. Various studies evaluated muscle activity using clinical evaluation, bite force measurement, electromyography (EMG), magnetic sensors and radiological examinations to assess the impact of mandibular fractures on masticatory muscles.

CONCLUSIONS

Mandibular condylar fractures can lead to significant changes in muscle activity, affecting mastication and TMJ functioning. EMG and computed tomography (CT) imaging play crucial roles in assessing muscle changes and adaptations following fractures, providing valuable information for treatment planning and post-fracture management. Further research is required to explore long-term outcomes and functional performance after oral motor rehabilitation in patients with facial fractures. Standardized classifications and treatment approaches may help improve the comparability of future studies in this field.

Evaluation of Masticatory Forces in Patients Treated for Mandibular Fractures: A Case-Control Study

Purpose:​​​​​ This study aimed to evaluate the masticatory forces in patients treated for mandibular fractures. To assess the magnitude of damage to the masticatory system caused by the various mandibular fractures and the period required for their normalization.

Materials and Methods: Data were recorded from the authentic and original bite force measurement device from 2015 to 2017. The sample was composed of 30 isolated mandible fractures patients, Group 1 consisting 15 patients with unilateral mandible fractures, Group 2 consisting 15 patients with bilateral mandible fractures, treated with ORIF (open reduction immobilization fixation) under general anesthesia, and Group 3 was a control group. Predictor variables were drawn from predefined intervals for three months (ninth POW) postoperative week.

The condition of wound healing was checked, and masticatory forces are measured at the first, fourth, sixth, and ninth postoperative weeks and compared with a control group of the same age and gender. The outcome variables were the success rate and associated complications.

Results: For the study, a total of 30 patients with 15 bilateral and 15 unilateral isolated mandibular fractures were included. The study result suggests that the patient had lower bite forces relative to the control group at all intervals. All patients showed a significant increase in the bite force values from the first to the fourth postoperative weeks (p = ‹0.001), which also increased significantly from the fourth to sixth postoperative weeks (p = ‹0.001), and from the sixth to the ninth week. 

Conclusion: ​​​​ Based on the results obtained from our study, we conclude that there is a temporary adverse effect on masticatory forces. Fracture of the bilateral mandible has a stronger influence on bite force than unilateral mandible fracture. These fractures also take a longer time to normalize.

Comparative evaluation of bite force in patients treated for unilateral mandibular condylar fractures by open and closed methods

BACKGROUND/AIM

Condylar fractures account for a large proportion (20% to 52%) of mandibular injuries. The goal of treating these fractures is to restore the occlusion, thereby re-establishing the masticatory function as close as possible to the patient's pre-trauma state. The aim of this study was to compare the bite forces following unilateral condylar fractures treated by open reduction and internal fixation (ORIF) with those managed by the closed method.

METHOD

Patients with unilateral mandibular condylar fractures were divided into two groups (n = 20) using a simple randomization method. Patients in group I were treated by open reduction and internal fixation (ORIF) using titanium miniplates and screws. Patients in group II were treated by the closed method with inter-maxillary fixation. Patients in both groups were evaluated pre-operatively and then post-operatively at one week, one month and three months for maximum bite force achieved at the central incisor, premolar and molar regions.

RESULTS

Pre-operative bite forces on the unaffected site were significantly higher than the affected site in both groups, whereas no significant difference was observed in bite forces between the unaffected and affected sites in both groups post-operatively. The bite forces achieved at both the unaffected and affected sites in the ORIF group were significantly higher than in the closed group.

CONCLUSION

Maximum bite forces differed significantly when the treatment was done with the open method, and the patients treated with the open method needed less time to achieve the maximum bite forces, thereby making an earlier return to function.

Mini - Retromandibular access to sub condylar mandibular fractures - Our experience

Condylar fractures alone accounts to about 25% to 40% of all the fractures of mandible. Management of condylar fractures has always been a controversy. Nowadays there has been more emphasis on open reduction of condylar fractures by the surgeons.The reasons could be the result of complications of closed reduction where the patient may not be able to masticate properly and deviation still present thereby the structural and functional loss forcing the surgeons' choice to open up. The anterior parotid approach has lesser risk of injury to parotid gland and also to facial nerve we attempted to use mini retro mandibular access for such fractures. So the aim was to explore the feasibility of the mini retro mandibular approach to sub condylar fractures. The patients reported to the department of oral and maxillofacial surgery department clinically and radio logically diagnosed and treated for condylar fractures were included. The maximal mouth opening, protrusive and lateral excursive movements, midline orientation with opposing arch, scar visibility, sialocele and facial nerve weakness were all recorded post operatively and compared with pre-operative recording. The mini retro mandibular access with anterior parotid transmessetric approach to sub condylar fractures can be the choice for the surgical management of sub condylar fractures which is absolutely easy, reliable, with less visible scar and with less chances of landing in facial nerve complications.

Is Open Reduction and Internal Fixation Sacrosanct in the Management of Subcondylar Fractures: A Comparative Study

PURPOSE

This paper is intended to compare and evaluate the better treatment option in the management of subcondylar fractures of the mandible.

MATERIALS AND METHODS

This study included 20 patients who were diagnosed clinically and radiologically to have sustained an isolated subcondylar fracture of the mandible. They were divided into two groups randomly. Group I included 10 patients who underwent treatment by intermaxillary fixation alone followed by active physiotherapy in the form of conservative management. Group II included 10 patients who underwent treatment by surgical intervention for open reduction and internal fixation under general anesthesia following elastic guidance. Factors such as maximal mouth opening, pain scores, and deviation of mandible on mouth opening were taken into consideration and evaluated.

RESULTS

It is observed that the patients in Group I had weight loss and restrictions in their social well-being in the early recovery phase, in addition to delay in return to function. In spite of the early return to function, patients in Group II were subjected to all kinds of surgical complications such as transient facial nerve injury, infection, and unesthetic scar. The maximal mouth opening and deviation of the mandible on mouth opening remained almost the same in both groups.

CONCLUSION

A regular follow up of operated patients post trauma is essential to obtain morphological and functional recovery. When the respective advantages and disadvantages of both treatment options were compared and evaluated, it was observed that patients treated by closed reduction had a better clinical and psychological outcome.

Prediction of Conservative Treatment Failure for Isolated Unilateral Mandibular Condylar Fractures Using Quantitative Measures: Suggestion of Indications for Intervention

BACKGROUND

Interest in the treatment of mandibular condyle fracture in cases of maxillofacial trauma has been a huge concern for decades because of a diversity of opinions on the topic and the relatively few studies conducted on individuals treated by physiotherapy or rehabilitation with or without intermaxillary fixation (IMF).

METHODS

We measured fracture gaps between bone ends over an 8-year period from 2012 to 2019. The study cohort was composed of only conservatively treated patients. This retrospective study was conducted to identify factors that influence treatment failure by comparing a functional treatment (physiotherapy) group with an IMF group in terms of fracture gaps and other variables. In addition, an algorithm was devised to enable clinicians to determine promptly whether IMF is needed for mandibular condylar fractures.

RESULTS

Significant correlations were observed between several parameters and malocclusion. Multiple regression analysis resulted in the following coefficients: 0.072 for fracture gap (P = 0.006) and 0.006 for age (P < 0.05) in functional treatment group. However, in the IMF group, correlations with malocclusion were 0.063 for fracture gap (P = 0.000) and 0.003 for age (P = 0.083).

CONCLUSIONS

We proposed a diagnostic algorithm for isolated unilateral mandibular condyle fractures that provides guidance regarding surgical correction. If indications for surgical correction, as regards anatomical location, fracture level, fracture gap between bone ends, and patient cooperability, are not satisfied, clinicians should select IMF or functional treatment (rehabilitation). If the fracture gap is less than 6 mm and the patient is cooperative, functional rehabilitation would be more suitable than IMF.

Development of a Wearable Mouth Guard Device for Monitoring Teeth Clenching during Exercise

Teeth clenching during exercise is important for sports performance and health. Recently, several mouth guard (MG)-type wearable devices for exercise were studied because they do not disrupt the exercise. In this study, we developed a wearable MG device with force sensors on both sides of the maxillary first molars to monitor teeth clenching. The force sensor output increased linearly up to 70 N. In four simple occlusion tests, the trends exhibited by the outputs of the MG sensor were consistent with those of an electromyogram (EMG), and the MG device featured sufficient temporal resolution to measure the timing of teeth clenching. When the jaw moved, the MG sensor outputs depended on the sensor position. The MG sensor output from the teeth-grinding test agreed with the video-motion analysis results. It was comparatively difficult to use the EMG because it contained a significant noise level. Finally, the usefulness of the MG sensor was confirmed through an exercise tolerance test. This study indicated that the developed wearable MG device is useful for monitoring clenching timing and duration, and the degree of clenching during exercise, which can contribute to explaining the relationship between teeth clenching and sports performance.

Lateral Pterygoid Muscle Biometric Modifications in Pterygoid Process Fractures Associated With Mandibular Fractures

PURPOSE

Pterygoid process fractures (PPFs) are classically associated with Lefort fractures but can also be encountered in association with other facial fractures such as mandibular fractures. The aim of this study was to estimate the frequency of PPFs associated with mandibular fractures and identify factors associated with PPF.

MATERIALS AND METHODS

We conducted a retrospective cross-sectional study using computed tomography scanning of patients having a mandibular fracture between November 2018 and April 2020. PPFs were classified using the classification by An et al. Volume, length, and width of both lateral pterygoid muscles have been evaluated by using an image processing software. Study population has been divided into 2 groups: fracture of pterygoid process or the absence of PPF. To evaluate the implication of lateral pterygoid muscle in the pathophysiology of PPF, we compared lateral pterygoid muscle volume, its maximal length, and width between both groups. Patients with bilateral fractures were excluded from this analysis.

RESULTS

About 304 patients with at least 1 mandibular fracture have been included in this study. About 18 patients presenting an association of mandibular fracture and PPF were finally selected. About 83.33% of the patients were concerned by a fracture of the posterior part of the mandible. The PPF was classified as type IIA by the classification of An et al for 94.4% of patients. The lateral pterygoid muscle volumes were significantly larger on the side of the PPF (P = .02). However, there were no significant differences in the maximum length (P = .49) and width (P = .1) of lateral pterygoid muscle.

CONCLUSIONS

Our study showed an association between mandibular fractures (mainly ipsilateral posterior) and isolated PPF through a lateral pterygoid muscle volume increase.

Biomechanical Evaluation of Mandibular Condyle Fracture Osteosynthesis Using the Rhombic Three-Dimensional Condylar Fracture Plate

PURPOSE

The aim of the present study was to evaluate the biomechanical stability of osteosynthesis in mandibular condyle fractures using a newly designed rhombic 3-dimensional (3D) condylar fracture plate and compare it with that using standard two 4-hole miniplates and with that in nonfractured condyles.

MATERIALS AND METHODS

Using 200 porcine mandibles, 3 different monocortical plating techniques were evaluated. The condyles were fractured along a defined line tangentially through the sigmoid notch and perpendicular to the posterior border. After anatomic reduction, osteosynthesis was performed using either standard rhombic 3D condylar fracture plates and standard screws (group A) or locking rhombic 3D condylar fracture plates, which were fixed either with standard screws (group B) or locking screws (group C). For comparison, nonfractured condyles (group D) and condyles fixed with standard two 4-hole miniplates and 8 screws (group E) were included. Using a universal mechanical testing machine (TIRA Test 2720; TIRA GmbH Schalkau, Germany), each group was subjected to linear loading from laterally to medially, medially to laterally, anteriorly to posteriorly, and posteriorly to anteriorly. The maximum axial force and displacement at the maximum force were measured. The mean values were compared for statistical significance using analysis of variance with Bonferroni's correction (statistical significance set at P < .05).

RESULTS

The main mode of failure in the plating techniques investigated was the pull out of screws from the proximal fragment. We found no statistically significant differences in the stability of osteosynthesis between the two 4-hole miniplates and the rhombic 3D condylar fracture plate when loading from posteriorly to anteriorly, laterally to medially, and medially to laterally. However, when loading from anteriorly to posteriorly, a statistically significant difference between the standard and locking system and the two 4-hole miniplate system was observed, with the latter proving more stable.

CONCLUSIONS

The results of the present biomechanical study suggest that the rhombic 3D condylar fracture plates are suitable for the treatment of condylar neck fractures. Both types of the plate are able to resist physiologic strains comparable to the two 4-hole miniplates.

Dynamic Stability Assessment of the Temporomandibular Joint as a Sequela of Open Reduction and Internal Fixation of Unilateral Condylar Fracture

PURPOSE

Dynamic stability of the temporomandibular joint (TMJ) is the characteristic of the joint to achieve normal function by harmonious, balanced, synchronized interactions of the various functional subunits of the stomatognathic system. The aim of this study was to evaluate changes in the mechanics and dynamics of the TMJ during recovery from surgical treatment of an isolated condylar fracture.

PATIENTS AND METHODS

This is a prospective cohort study involving 30 patients who underwent open reduction and internal fixation for an isolated unilateral condylar fracture and were clinically asymptomatic at 6 months after surgery. The dynamics of the TMJ were assessed by bite-force analysis, both static and dynamic, to assess masticatory efficiency. Surface electromyography was recorded to assess changes in muscle dynamics. Joint vibration analysis was performed to evaluate the internal functioning of the TMJ. All the assessments were carried out bilaterally to allow comparison of the injured and uninjured joints, and the data were analyzed with the paired t test and independent-samples t test. Statistical significance was considered at P < .05.

RESULTS

The study included 18 male and 12 female patients aged between 20 and 40 years. Bite-force analyses showed significantly higher bite forces on the uninjured side at 6 months after surgery. Similarly, surface electromyography analysis showed increased muscle activity on the affected side pointing toward some compensatory hyperactivity in the masticatory muscles. Joint vibration analysis showed that there was increased friction during function in both the injured and uninjured joints.

CONCLUSIONS

The observations in this study suggest that residual imbalances are present in the TMJ at 6 months after open reduction and internal fixation of condylar fractures. Therefore, long-term studies are required to establish a complete timeline of adaptive changes occurring in the TMJ after condylar fractures, especially in comparison with other treatment modalities.

Does Fracture Pattern Influence Functional Outcomes in the Management of Bilateral Mandibular Condylar Injuries?

The purpose of this study was to compare the functional outcomes of different types of bilateral mandibular condylar fractures. This was a retrospective study of patients with bilateral mandibular condylar fractures at a level-1 trauma center over a 15-year period. The primary predictor variable was fracture pattern, classified as type I (bilateral condylar), type II (condylar-subcondylar), or type III (bilateral subcondylar). Secondary predictor variables were demographic, injury-related, and treatment factors. Bivariate associations between the predictors and complication rates were computed; a multiple logistic regression model was utilized to adjust for confounders and effect modifiers. Thirty-eight subjects with bilateral condylar injuries met the inclusion criteria. The sample's mean age was 37.6 + 18.2 years, and 16% were female. The most common mechanisms of injury were motor vehicle collisions (53%) and falls (29%). Seventy-four percent had associated noncondylar mandibular fractures, and 32% of cases had concomitant midface fractures. Fifty-three percent of cases were classified as type I, 21% as type II, and 26% as type III. Ten subjects (26%) were managed with open reduction and internal fixation. The average length of follow-up was 4.5 + 6.3 months. After adjusting for confounders and effect modifiers, the type of fracture was a significant predictor of functional complications with type II injuries having the highest likelihood of a poor functional outcome (odds ratio: 7.77, 95% confidence interval: 1.45-41.53, p  = 0.02). Asymmetric bilateral mandibular condylar fractures may be associated with an increased risk of poor functional outcomes.

"Closed Reduction" Principles Can Manage Diverse Conditions of Temporomandibular Joint Vertical Height Loss: From Displaced Condylar Fractures to Idiopathic Condylar Resorption

PURPOSE

The aim of this case series was to describe a modification of the classic "closed reduction" technique to manage unilateral or anterior open bite owing to a loss in vertical height (LVH) caused by several disorders and pathologies other than displaced condylar fractures.

MATERIALS AND METHODS

The protocol included insertion of an occlusal appliance to increase the height of the premature contact and the width of the open bite, stabilization of the dental arches by rigid arches, and the use, during sleep, of rubber bands in the open bite region to pull the mandible cranially. In addition, when awake, the patient performed physiotherapy exercises to guide the mandible into maximum intercuspation. The increased open bite enhanced the effect of the rubber bands in guiding the mandible into the original habitual occlusion and the rigid arches served to minimize tooth eruption.

RESULTS

The present cases showed the favorable outcome of this low-risk treatment in the re-establishment of the original habitual occlusion within 1 to 4 weeks and without reconstruction of the LVH.

CONCLUSION

The efficacy of this complication-free approach to correct occlusion in various conditions of LVH suggests that this protocol should be applied before venturing into surgical intervention.

Treatment of fractures of the mandibular condylar head with ultrasound-activated resorbable pins: early clinical experience

Controversy continues about the benefits and disadvantages of open reduction and internal fixation of fractures of the condylar head. Once a decision to treat surgically has been made, an appropriate method of fixation must be chosen. Standard titanium fixation has a number of complications, including the risk of protrusion of the screw beyond the condylar head and the possible need for removal later. Resorbable fixation is an alternative, and ultrasound-activated resorbable pins are a new innovation. We have treated a series of 15 patients with 17 fractures of the condylar head, in which the use of ultrasound-activated resorbable fixation has provided adequate strength and stability during early healing. Complications included technical difficulties in achieving complete anatomical reduction as a result of fragmentation of the condylar head, and three facial nerve palsies, two of which recovered within three months. No pins failed, and there was no sign of instability during healing.

Conservative interdisciplinary treatment of a case with multiple facial and condyle fractures

The purpose of this case report is to describe an interdisciplinary approach for a 51-year-old male who underwent multiple facial fractures including bilateral condyle fractures. The patient underwent emergency surgery, which included open reduction of the maxilla and mandibular symphysis and closed reduction of the bilateral condyle fractures. Although the patient recovered a comfortable range of mouth opening and alleviation of the temporomandibular joint (TMJ) symptoms after surgery, he suffered from a large anterior-posterior discrepancy due to less stability on the condyle-fossa relationships and from open bite with contacts only on both second molars and right second premolars. In this case, first, to increase the occlusal contact, comprehensive orthodontic treatment was completed. Second, occlusal equilibration was selectively performed to relieve the interferences and establish a stable range of mandibular movement without any changes in the vertical dimension. Third, both the upper central incisors and left lateral incisor were minimally restored with splinted and single zirconia crowns, which had modified lingual contours to provide adequate anterior guidance permitting the anterior-posterior discrepancy of the posterior teeth during protrusion. This conservative interdisciplinary treatment, including open and closed reduction, orthodontic treatment, occlusal adjustment, and minimal prosthetic restorations, resulted in a stable mandibular position and recovery of mastication function.

Efficacy of Retromandibular Transparotid Approach for the Management of Extracapsular Subcondylar Mandibular Fractures Using 2-mm Titanium Miniplates: A Prospective Clinical Study

PURPOSE

The aim of this study was to evaluate the long-term clinical and radiologic results of the retromandibular transparotid approach to displaced extracapsular subcondylar mandibular fractures.

PATIENTS AND METHODS

A prospective cohort study was conducted over a period of 5 years on patients surgically treated for displaced extracapsular subcondylar mandibular fractures by the retromandibular transparotid approach. Variables including the type of fracture, degree of mouth opening, fracture displacement, deviation, excursive movements of the mandible, and facial nerve function were monitored before and after treatment. Appropriate statistics were computed.

RESULTS

Thirty-nine patients with 47 fractures were evaluated. There were 34 subcondylar fractures (located below the sigmoid notch) (87%), and 5 fractures were located in the head region in bilateral cases. Of the fractures, 31 (79%) were unilateral and 8 (21%) were bilateral. In a multivariate study, condylar coronal displacement, coronal sagittal displacement, difference in the ramal height, maximal interincisal distance, protrusive movements, and deviation of the mandible on opening showed statistically significant differences in pretreatment and post-treatment patients (P = .001). The interincisal distance was 46.8 mm (SD, 5.2 mm) postoperatively versus 24.1 mm (SD, 6.7 mm) before treatment. The average range of protrusion was significantly lower (P = .001) in patients before treatment, at 1.9 mm (SD, 1.2 mm), when compared with 6.1 mm (SD, 2.0 mm) postoperatively. During mouth opening, deviation of the mandible is often a sign of compensatory movement of the contralateral joint due to shortening of the ascending ramal height on the affected joint. The mean deviation of the mandible from the midline was 4.2 mm (SD, 1.0 mm) in patients before treatment, with a significant difference (P = .001) in patients after treatment, with a mean of 1.9 mm (SD, 0.995 mm). Temporary injuries to the facial nerve branches were observed in 3 cases (8%) 1 week after treatment, which later resolved within 3 weeks to 3 months.

CONCLUSIONS

The retromandibular transparotid approach provides good exposure and facilitates accurate reduction and fixation of the subcondylar fragment with positive outcomes, good cosmetic results, and rare major complications. Most facial nerve injuries are transient in nature after this approach. A Synthes 2-mm titanium single mini-plate (West Chester, PA) provides stable results after fixation.

Assessment of masticatory function using bite force measurements in patients treated for mandibular fractures

Bite force measurements are excellent criteria for assessment of masticatory efficiency. The purpose of this study was to assess the effect of mandibular fractures on the bite forces of patients treated for such fractures. Patients who were surgically treated for isolated mandibular fractures in the Department of Oral and Maxillofacial Surgery from January 2006 to December 2007 were included in the study. Patients were asked to bite on a bite force transducer on the first, fourth, sixth, and ninth postoperative weeks. The bite force values were compared with those of age, sex, and weight-matched controls. A total of 60 patients were included in the study. It was found that maximum bite forces in patients were significantly less than in controls for several weeks after surgery. After the ninth postoperative week, the maximum bite force measured < 65% the normal in patients with isolated angle fractures and > 80% the normal in patients with isolated parasymphysis fractures. The same values reduced to < 60% in patients with fractures of angle and parasymphysis and < 70% in patients with fractures of parasymphysis and condylar complex. An inverse relationship was found between the bite force values and the number of fractures of the mandible. We also found lower bite forces and longer period for normalization in patients who had fractures in those regions of the mandible which are more significantly associated with the masticatory apparatus for example angle or condyle of the mandible.

Severe open bite due to traumatic condylar fractures treated nonsurgically with implanted miniscrew anchorage

This case report illustrates the use of miniscrews to treat a patient with an open bite caused by mandibular condylar fractures. The patient was 36 years old when she visited our hospital with a chief complaint of difficulty with chewing. She had suffered condylar and maxillary bone fractures in a traffic accident 6 months before her visit. She had an anterior open bite and Angle Class II molar relationships. Her mandibular midline was deviated to the right relative to the maxilla. The cephalometric analysis showed a skeletal Class II relationship. Titanium miniscrews were implanted in the bilateral maxillary buccal areas. The maxillary dentition was retracted and intruded by using elastomeric chains and miniscrews. After this treatment, an Angle Class I molar relationship was achieved, her overjet and overbite became ideal, and a good facial appearance was obtained. The total active orthodontic treatment period was 33 months. Treating an open bite with molar intrusion often leads to counterclockwise rotation of the mandible; however, in this patient, the mandible was moved anteriorly and upward. We believe that this movement was caused by the patient's condylar fractures and the subsequent remodeling. Although there was some relapse, our results suggest that implant anchorage is useful for correcting anterior open bites originating from condylar fractures.

Electromyographic analysis of anterior temporalis and superficial masseter muscles in mandibular angle fractures--a pilot study

INTRODUCTION

Fracture of the mandible occurs more frequently and the surgical anatomy of the mandible and adjacent structures is extremely important in understanding the pattern of fracture, the displacement of fractured fragments, and factors necessary for uncomplicated healing. In the field of dentistry, surface electromyography, electrokinesiography, and more recently, TMJ sound analysis have been particularly important developments. Previous electromyographic studies involving anterior temporalis and superficial masseter have been conducted in mandibular condylar fractures and in orthognathic and cosmetic procedures of the jaws.

MATERIALS AND METHODS

This experimental study was undertaken to measure the electrical activity of the anterior temporalis and superficial masseter muscles in mandibular angle fracture cases (n = 6) and the changes in the electrical activity over a period of 6 months.

RESULTS

The study shows that muscle activity increases significantly over a period of time but never matches the muscle activity of the normal subjects of same sex and age in a follow-up of 6 months post-trauma.

DISCUSSION

Electrodiagnostic testing is a potentially valuable tool for the management of patients who have suffered craniomaxillofacial trauma. Electromyography is being employed in clinical practice, and allows the inclusion of quantitative data on the qualitative aspects of a diagnosis. These data are often of significant importance in the correct management of therapy and patient follow-up, particularly if the subject is at risk of developing a different and/or more serious disease.

Three-dimensional mandibular motion after closed and open reduction of unilateral mandibular condylar process fractures

OBJECTIVE

To detect the changes in 3D mandibular motion after two types of condylar fracture therapies.

MATERIALS AND METHODS

Using a 3D motion analyzer, free mandibular border movements were recorded in 21 patients successfully treated for unilateral fractures of the mandibular condylar process (nine patients: open reduction, rigid internal fixation, and functional treatment; 12 patients: closed reduction and functional treatment; follow-up: 6-66 months), and in 25 control subjects.

RESULTS

No differences were found among the groups at maximum mouth opening (MO), protrusion and in lateral excursions. During opening, the patients had a larger maximal deviation to the fractured side than the controls (controls 2.3 mm, open treatment 3.9 mm, closed treatment 4.2 mm; Kruskal-Wallis test, p=0.014; closed treatment vs. controls, p=0.004), with a larger coronal plane angle (controls 2.4°, open treatment 3.6°, closed treatment 4.4°; p=0.016; closed treatment vs. controls, p=0.013). In the closed treatment patients, a longer follow-up was related to increased maximum MO (p=0.04), sagittal plane angle (p=0.03), and reduced lateral mandibular deviation during MO (p=0.03).

CONCLUSION

Mandibular condylar fractures can recover good function; some kinematic variables of mandibular motion were more similar to the norm in the open treatment patients than in closed treatment patients.

The adaptive response of jaw muscles to varying functional demands

Jaw muscles are versatile entities that are able to adapt their anatomical characteristics, such as size, cross-sectional area, and fibre properties, to altered functional demands. The dynamic nature of muscle fibres allows them to change their phenotype to optimize the required contractile function while minimizing energy use. Changes in these anatomical parameters are associated with changes in neuromuscular activity as the pattern of muscle activation by the central nervous system plays an important role in the modulation of muscle properties. This review summarizes the adaptive response of jaw muscles to various stimuli or perturbations in the orofacial system and addresses general changes in muscles as they adapt, specific adaptive changes in jaw muscles under various physiologic and pathologic conditions, and their adaptive response to non-surgical and surgical therapeutic interventions. Although the jaw muscles are used concertedly in the masticatory system, their adaptive changes are not always uniform and vary with the nature, intensity, and duration of the stimulus. In general, stretch, increases neuromuscular activity, and resistance training result in hypertrophy, elicits increases in mitochondrial content and cross-sectional area of the fibres, and may change the fibre-type composition of the muscle towards a larger percentage of slow-type fibres. In contrast, changes in the opposite direction occur when neuromuscular activity is reduced, the muscle is immobilized in a shortened position, or paralysed. The broad range of stimuli that affect the properties of jaw muscles might help explain the large variability in the anatomical and physiological characteristics found among individuals, muscles, and muscle portions.

Prospective closed treatment of nondisplaced and nondislocated condylar neck and head fractures versus open reposition internal fixation of displaced and dislocated fractures

OBJECTIVE

assessment of open reduction internal fixation in displaced or dislocated fractures of the condylar neck and head assessed versus closed treatment of nondisplaced, nondislocated fractures.

MATERIALS AND METHODS

One hundred and twenty patients suffering from 158 fractures; classes II to V according to Spiessl and Schroll, e.g., displaced and dislocated fractures were operated on; classes I and VI nondisplaced, nondislocated fractures were treated conservatively. At 1year, facial symmetry, pain, facial nerve function, and scarring were assessed clinically; reossification and fragment angulation were assessed from radiographs; vertical position, incisal maximum movements, and condyle translation were judged by millimeters.

RESULTS AND DISCUSSION

Clinical courses were uncomplicated in classes I to IV and did reach horizontal and vertical fragment reposition with minor remodeling in follow-up. Single cases evinced persistent pain, dysocclusion, facial nerve palsy, and plate fractures. Results were less successful in classes V and VI: although open reposition internal fixation showed good repositioning in class V, marked vertical bone remodeling occurred; single cases suffered from pain, dysocclusion, and plate fracture. Class VI cases had the worst translation, likewise marked condyle remodeling, and frequent dysocclusion.

CONCLUSION

Classes V and VI remain challenging to treat, while the other classes can be treated reliably with this study's rationale. Condyle remodeling in classes V and VI, translation in class VI may benefit prospectively from even more careful mobilization, improved osteofixation as minimalized operation trauma.

The treatment of condylar fractures: to open or not to open? A critical review of this controversy

The treatment of condylar process fractures has generated a great deal of discussion and controversy in oral and maxillofacial trauma and there are many different methods to treat this injury. For each type of condylar fracture, the techniques must be chosen taking into consideration the presence of teeth, fracture height, patient's adaptation, patient's masticatory system, disturbance of occlusal function, deviation of the mandible, internal derangements of the temporomandibular Joint (TMJ) and ankylosis of the joint with resultant inability to move the jaw, all of which are sequelae of this injury. Many surgeons seem to favor closed treatment with maxillomandibular fixation (MMF), but in recent years, open treatment of condylar fractures with rigid internal fixation (RIF) has become more common. The objective of this review was to evaluate the main variables that determine the choice of method for treatment of condylar fractures: open or closed, pointing out their indications, contra-indications, advantages and disadvantages.

Botulinum Toxin in Closed Treatment of Mandibular Condylar Fracture

BACKGROUND

The topic of condylar injury in adults has generated more discussion and controversy than any other in the field of maxillofacial trauma. The treatment of condylar fractures in adults is still a highly debated theme.

METHODS

Patients with unilateral subcondylar or condylar neck fractures of the mandibula without any significant angulation of the condylar head were managed with closed-treatment protocol. Closed treatment was applied through the injection of 100 units of botulinum toxin A, diluted to a concentration of 20 IU/mL, into the muscles of mastication of the fractured side. Masseter and anterior fibers of temporalis muscles were reached through percutaneous extraoral route and 30 IU of the toxin was injected to each muscle. Additional 40 IU of the toxin was injected around the fractured bone fragments through transmucosal intraoral route to paralyze medial and lateral pterygoid muscles as much as possible. An asymmetric occlusal splint was applied for maxillomandibular fixation to restore the vertical height for 10 days. Functional therapy with intermaxillary guiding elastics was advocated for 2 months.

RESULTS

There were no complications related to either toxin injections or splint application procedures. The toxin was effective on all occasions. Fractured condylar process and ramus of the mandibula were in good approximation and remained in reduced positions. None of the patients had any occlusal disturbance, mandibular asymmetry, or joint dysfunction in the follow-up period.

CONCLUSIONS

We believe that modification of treatment options concerning the clinical situation of the patients is the best method for condylar injury. The purpose of this study is to present and discuss the results achieved in closed treatment of a selected group of patients with mandibular condylar fractures to whom botulinum toxin A was injected to relieve the spasm of muscles of mastication, along with special splint application.

Biomechanical evaluation of different types of rigid internal fixation techniques for subcondylar fractures

PURPOSE

The aim of this study was to evaluate the biomechanical stability of various internal fixation systems for subcondylar fractures.

MATERIALS AND METHODS

Eighteen identical synthetic mandibles were used. Left condylar processes were cut to mimic perpendicular subcondylar fracture and right sides were mimicked oblique subcondylar fracture. The fixation systems used included single 4-hole mini adaptation plate, double fixation with the same plates, single 4-hole mini dynamic compression plate (DCP), Eckelt lag screw system, Wurzburg lag screw plate system and double 4-hole biodegradable miniplates made of poly L-lactide (PLLA). In oblique fractures, one of the screws fixing plates was used bicortically through bone fragments. The loading vector simulated physiologic forces to the condyle on biting with servohydraulic testing machine until failure was reached. Load-displacement curve, maximum load for failure, and stiffness were measured.

RESULTS

In perpendicular fracture, double adaptation plate showed the highest level of tolerance load followed by Eckelt lag and double PLLA plate. In stiffness, double adaptation plate and Eckelt lag screw showed higher level of stiffness, whereas double PLLA was almost at the same level of single DCP. In oblique fracture, double adaptation plate showed the highest strength.

CONCLUSIONS

In this laboratory setting, double adaptation plates fixation proved to have superior biomechanical stability in both fracture conditions. Eckelt lag screw showed good stability in the perpendicular fracture, however, it was weak in the oblique fracture.

A Comparative Biomechanical Evaluation of Mandibular Condyle Fracture Plating Techniques

OBJECTIVES

The aim of this study was to comparatively evaluate the resistance of 3 plating rigid internal fixation techniques for mandibular condylar process fractures.

MATERIALS AND METHODS

Synthetic hemi-mandible replicas made in polyurethane were used to evaluate a control, and 3 mandibular condyle plating techniques using 2-mm system plates and screws. The plating techniques were fixation with a 4-hole plate and 4 6-mm screws, fixation with a 4-hole plate and 4 8-mm screws and fixation with 2 4-hole plates with 4 6-mm screws each. Each group was subjected to linear loading in medial to lateral and anterior to posterior directions by an Instron 4411 servohydraulic mechanical testing unit (Instron Corp, Norwood, MA). Load peak value and peak displacement were measured. Means and standard derivations were derived and compared for statistical significance using an analyses variance (P < .05) and compared by Tukey test.

RESULTS

Statistically significant differences were noted between fixation groups for the different mechanical measures evaluated under the different directions of linear loading. The 2-plate fixation system presented better behavior, followed by 1 plate with 4 8-mm screws and 1 plate with 4 6-mm screws. The fixation systems used were more resistant to antero-posterior load and the use of 8-mm screws improved the resistance of the fixation when compared with 6-mm screws only in the antero-posterior test.

CONCLUSION

Under the conditions tested the 2-plate fixation system provided the most favorable mechanical behavior. We can suggest that lengthy screws, with bicortical engagement, can increase the stability at fixation of mandibular condylar process fractures.

A Biomechanical Comparison of 2 Techniques for Reconstructing Atrophic Edentulous Mandible Fractures

OBJECTIVES

The purpose of this investigation was to evaluate and compare the biomechanical behavior of 2 techniques for the reconstruction of atrophic edentulous mandible fractures.

MATERIALS AND METHODS

Thirty polyurethane atrophic edentulous mandible replicas (Sawbones, Vashon Island, WA) were used in this investigation (10 controls, 10 replicas of 2 different fixation techniques). The first reconstruction technique was a traditional titanium locking reconstruction plate affixed to the lateral border (buccal surface) of the mandible. The second reconstruction technique used the same type of plate, but placed it on the inferior border of the mandible. Both constructs were subjected to vertical loading at the symphysis and torsional loading at the body regions of the mandible replicas by an Instron 1331 (Instron, Canton, MA) servohydraulic mechanical testing unit. Mechanical deformation data within a 0-900 N range were recorded. Maximum load, displacement at maximum load, and stiffness were determined. Means and standard deviations were derived and compared for statistical significance using a Fisher's Protected Least Significant Differences Test with a confidence level of 95% (P < .05). Second- and third-order polynomial best-fit curves were also created for each group to further evaluate the mechanical behavior.

RESULTS

For symphysis loading, statistically significant differences were noted between the control group and both of the plating techniques for displacement at maximum load. However, no differences were noted between the experimental groups for displacement at maximum load, stiffness, or maximum load. For body loading, statistically significant differences were noted between the control group and the inferior border plating group for displacement at maximum load. However, no differences were noted between the experimental groups for displacement at maximum load, stiffness, or maximum load.

CONCLUSION

During this bench top investigation, there were no significant differences noted in mechanical behavior between the 2 specific experimental groups for any of the conditions measured. When placed in the context of functional parameters, both of the plating techniques met or exceeded the requirements for loading.

Prospective evaluation of a pragmatic treatment rationale: open reduction and internal fixation of displaced and dislocated condyle and condylar head fractures and closed reduction of non-displaced, non-dislocated fractures

This study prospectively evaluated closed reduction (CR) outcomes in non-displaced, non-dislocated high-condylar and condylar-head fractures (Class VI after Spiessl and Schroll) and open reduction and internal fixation (ORIF) of displaced (Class III) or dislocated (Class V) fractures. Thirty-eight patients with 54 fractures (16 (42%) with bilateral fractures, 14 (37%) CR, 24 (63%) ORIF) were enrolled in a 1 year follow-up that 18 patients with 33 fractures completed. Condylar translation in Class VI fractures recovered to 11 mm for vertical opening, 8mm for protrusion and 10 mm for mediotrusion; Class III synonymously 8 mm, 8 mm and 6 mm; and Class V 7 mm, 6mm and 7 mm; incisal movements recovered to 38 mm, 8 mm and 8 mm in Class VI; 55 mm, 7 mm and 10 mm in Class III with 1 (8%) malocclusion, 1 (8%) impaired vertical opening and 55 mm, 7 mm and 9 mm in Class V with 2 (18%) malocclusions. Fragment-reduction versus the non-fractured condyle was -0.3 mm to +1.3 mm and +3 degrees to +9 degrees in Class VI, -1 mm to -0.2 mm and +3 degrees to +2 degrees in Class III, -3.3 mm to +3.1 mm and -11.2 degrees to +1 degrees in Class V. Malocclusion and joint locking were unreliable determinants for a treatment decision, being forged by concomitant fractures. Joint movements were within normal range at 1-year follow-up except Classes III and V vertical opening translation. After predefined criteria, 92% successful outcomes were attained. Multiple factor analysis should be used to prospectively evaluate the unacceptable clinical outcomes. Class VI fractures with intact vertical support should prospectively be evaluated whether these benefit from ORIF.

Treatment of mandibular condylar process fractures: Biological considerations

The topic of condylar injury in adults has generated more discussion and controversy than any other in the field of maxillofacial trauma. It is an important subject because such injuries are common and complications of trauma to the temporomandibular joint (TMJ) are far-reaching in their effects. Why are there so many different methods to treat this injury? How can seemingly disparate treatment options all produce satisfactory outcomes in the majority of patients? The reason lies with the biological adaptations that occur within the masticatory system that are poorly understood, not readily quantifiable, and variable from one person to the next. This discussion presents our current understanding of the adaptations that must occur to provide the patient with a satisfactory outcome. The adaptations for patients treated open are different than for those treated closed. However, it is when these adaptations fail to occur that unsatisfactory outcomes occur, regardless of how they were treated.

A biomechanical evaluation of mandibular condyle fracture plating techniques

OBJECTIVES

The purpose of this investigation was to evaluate the biomechanical behavior of various rigid internal fixation techniques for mandibular condylar process fractures.

MATERIALS AND METHODS

Synthetic mandible replicas (Synbone, Landquart, Switzerland) were used to evaluate a control, and four monocortical mandibular condyle plating techniques. Each group was subjected to linear loading in lateral to medial, medial to lateral and posterior to anterior directions by an Instron 1331 (Instron, Canton, MA) servohydraulic mechanical testing unit. Yield load, yield displacement, and stiffness were measured. In addition, each group was subjected to torsional loading using an Instron 8521 (Instron). Yield torque, yield rotation, and stiffness were measured. Five samples were tested for each group and method of loading (n = 100). Means and standard deviations were derived and compared for statistical significance using a 1-way analysis variance (P <.05). Third-order polynomial best-fit curves were also created for each group to further evaluate and compare the mechanical behavior.

RESULTS

Statistically significant differences were noted between fixation groups for the different mechanical measures evaluated under the different conditions of linear loading. Statistically significant differences were noted between groups for yield rotation during torsional loading. Although different in magnitude, similar patterns of mechanical behavior were observed in the third-order polynomial best-fit curves for lateral to medial loading, medial to lateral loading and torsional loading. For posterior to anterior loading, different patterns of mechanical behavior were noted between the experimental groups, but similar behavior was noted between the control and mini dynamic compression plate

CONCLUSIONS

While differences were noted between each of the fixation systems in their abilities to resist loads under the conditions tested, the mini dynamic compression plate provided the most favorable mechanical behavior. Based on the presumed clinical parameters, we can suggest that none of the systems evaluated were ideal for the treatment of mandibular condyle fractures, but that the mini dynamic compression plate is the closest to an effective means for reconstruction.