Masticatory motion after surgical or nonsurgical treatment for unilateral fractures of the mandibular condylar process.

PURPOSE: We sought to compare mandibular motion during mastication in patients treated in either an open or a closed fashion for unilateral fractures of the mandibular condylar process. PATIENTS AND METHODS: Eighty-one male patients with unilateral condylar process fractures were treated either with (n = 37) or without (n = 44) surgical reduction and rigid fixation of their condylar process fractures. At 6 weeks, 6 months, 1 year, and 2 years after treatment, the subjects' chewing cycles were recorded using a magnetic sensor array (Sirognathograph; Siemens Corp, Bensheim, Germany) while chewing Gummi-Bears (HARIBO, Bonn, Germany) unilaterally on the same side as the fracture and on the opposite side. The chewing cycles were analyzed using a custom computer program, and the duration, excursive ranges, and 3-dimensional cycle shape were compared between the 2 treatment groups at each time interval using multilevel linear modeling statistics. RESULTS: The 2 treatment groups did not differ significantly for any measure of cycle duration or any excursive range (except lateral excursions at 1 year post-treatment) at any of the time intervals. However, the 3-dimensional cycle shapes of the 2 groups did differ significantly at all time intervals. CONCLUSION: Surgical correction of unilateral condylar process fractures has relatively little effect on the more standard measures (duration and excursive ranges) of masticatory function. However, surgical correction better normalizes opening incisor pathways during mastication on the side opposite the fracture.     

Recovery of mandibular motion after closed and open treatment of unilateral mandibular condylar process fractures

The purpose of this study was to determine the rate of recovery of mandibular motion in patients treated for fractures of the mandibular condylar process. One hundred and thirty-six patients (111 men, 25 women), 74 treated by closed and 62 by open methods, were included. They underwent testing of mandibular and condyle mobility at 6 weeks, 6 months, and 1, 2, and 3 years post surgery. Their ranges of motion were compared to those of 52 controls (26 men and 26 women). A jaw-tracking device was used to assess mandibular motion. Multilevel statistical models were used to assess differences between groups, and to estimate rate of recovery in the fracture patients. In general, patients with unilateral fractures of the condylar process had maximum excursions that returned to normal values within 3 years after fracture, regardless of treatment. Patients treated open exhibited a faster rate of improvement in maximum interincisal opening than patients treated closed (0.43 mm/month vs 0.15 mm/month, respectively), but part of the difference was due to a significantly smaller opening after 6 weeks for the patients treated open (38 mm vs 42 mm, respectively). Patients treated open also exhibited a faster rate of improvement in maximum excursion toward the fracture side than patients treated closed (0.10 mm/month vs 0.04 mm/month, respectively). Based upon this study, patients with unilateral fractures of the condylar process, who are treated closed and not put into maxillomandibular fixation but are instructed in physical therapy, can be expected to achieve normal maximum excursions within 3 years after treatment. Patients treated open will have reduced maximum opening initially, but may reach normal levels of opening sooner than patients treated without surgery. Patients treated without surgery may have smaller than normal excursion toward the non-fracture side for at least 3 years after fracture, especially if their fracture was at or above the condylar neck. Improvement rates for other maximum excursions are similar for patients treated with or without surgery.     

Changes in the masticatory cycle following treatment of posterior unilateral crossbite in children.

In a previous study, we established that young children with unilateral posterior crossbite have a longer mandibular ramus and more superiorly and posteriorly positioned condyles on the crossbite side. In this study, we evaluated chewing cycle shape and duration in 14 of the patients before treatment, and we looked for changes in cycle shape and duration 6 months after treatment with rapid palatal expansion. Mandibular kinematics was recorded while chewing gum using an optoelectric recording system at 100 Hz. Subjects were asked to chew normally for 20 cycles, chew on the crossbite side only for 20 cycles, and chew on the noncrossbite side only for 20 cycles. A special computer program selected the 10 most representative cycles from each series and computed an average duration and an average maximum excursion along 3 orthogonal axes. Multilevel linear models were used to generate an 8th-order polynomial describing average cycle shape and to test for statistically significant differences in shape between the patients and the controls and between the patients before and after treatment. Before treatment, the patients chewed more slowly than did the controls. Treatment shortened their cycle duration to equal control values. Before treatment, the patients also had larger maximum excursions than did the controls and exhibited a reverse-sequence cycle shape when chewing on the crossbite side. Treatment did not alter the patients' abnormal cycle shape. These results suggest that some features of the masticatory kinematics respond to orthodontic treatment alone, but others do not.     

Bite forces after open or closed treatment of mandibular condylar process fractures.

PURPOSE: This study compared maximum voluntary bite forces in patients who received either open or closed treatment for fractures of the mandibular condylar process. PATIENTS AND METHODS: One hundred fifty-five patients (127 male, 28 female) with unilateral fractures of the mandibular condylar process (91 treated closed and 64 treated open) were included in this study. Maximum voluntary bite forces were measured at 6 weeks, 6 months, and 1, 2, and 3 years after fracture. At each trial, unilateral maximum voluntary bite force was measured at 4 different tooth positions bilaterally using a standard transducer. Electromyography (EMG) of the masseter muscles was also recorded during the bite force measurements, and ratios of the working/balancing side EMG were calculated. Analysis of the data was performed using standard statistical methods. RESULTS: The only significant difference between the 2 samples was in the level of fractures on the condylar process. No patients treated open had fractures of the "head" of the condylar process, whereas there were 11 in the group treated closed. No differences were observed in maximum voluntary bite forces between the 2 treatment groups at any time period, or were there correlations between bite force magnitude and location of the fracture, displacement of the fracture, or any other variable studied. Both groups showed a significant recovery of maximum bite force from the 6-week to the 6-month testing session. For both groups, working/balancing EMG ratios were significantly greater when subjects were biting on the side opposite the fracture. When biting on that side, the working/balancing EMG ratios were higher in the closed treatment group, but the difference did not reach significance. CONCLUSIONS: Maximum voluntary bite forces in patients treated for mandibular condylar process fractures do not differ significantly when treatment is open or closed. Neuromuscular adaptations to the fractured mandibular condylar process occur in both groups.     

Association between shape of the mandibular condylar head and the occurrence of unilateral condylar fracture – A retrospective computed tomographic study

This retrospective study aims to evaluate the correlation between the shape of the mandibular condylar head and the incidence of unilateral condylar fracture using computed tomography.Medical records of patients diagnosed with unilateral condylar fractures from the year 2012–2019 were reviewed. The shape of the condylar head on the non - fractured side was analysed using a Radiant Dicom Viewer. The analysis was done using both visual and analytical methods. In the analytical method, a horizontal line was drawn at the base of the curvature of the condylar head. The highest peak point of the head was marked, and a perpendicular line was drawn connecting the highest point to the horizontal line. The shape was categorized into four types as convex, flat, angled, and round based on these lines.201 CT scans were examined, of which 69 were excluded as they did not meet the inclusion criteria. The remaining 132 were included in our study. On examining the shape, flat-shaped condyle was seen in 57 scans (43.2%), followed by convex in 31 scans (23.4%), angled in 30 (22.7%) and round in 14 scans (10.6%). The relationship between the shape of the mandibular condylar head and the incidence of unilateral condylar fracture was analysed using a chi-square test, which showed high statistical significance (p value 0.0001). The flat-shaped condylar head was more prone to fracture, and the round-shaped condylar head was least prone to fracture.In conclusion, the shape of the mandibular condylar head had a statistically significant association with the incidence of unilateral condylar fracture. The assessment of the shape of the condylar head can be taken as a guide to suspect condylar fractures and other associated mandibular fractures.     

Functional outcomes following surgical treatment of bilateral mandibular condylar fractures

Debate continues regarding unilateral or bilateral treatment for mandibular condylar fractures. This retrospective study evaluates the functional outcomes of bilateral condylar process fractures after surgical intervention. From May 1994 to December 2004, 51 adult patients with bilateral mandibular condylar process fractures were studied. There were 33 cases of bilateral condylar fractures (type I); 12 cases of condylar-subcondylar fractures (type II); and six cases of bilateral subcondylar fractures (type III). All patients underwent open reduction and internal fixation. Four patients had chin deviation, six had malocclusion, three had poor chewing function and eight had limited mouth opening. Type I patients had a significantly higher incidence of limited mouth opening (P = 0.039) and associated maxillary fractures (n = 12) and psychiatric disease (n = 6) which yielded significantly poor functional outcomes. Complications included transient facial paresis (n = 4), fracture and loosening of postoperative plates (n = 3) and surgical wound infections (n = 2). Open reduction with rigid fixation for bilateral condylar fractures provided satisfactory functional outcomes in this study. Concomitant maxillary fractures and underlying psychiatric problems are poor outcome factors. Aggressive rehabilitation in the first 9 months is important for early functional recovery.     

Preliminary functional results of endoscope-assisted transoral treatment of displaced bilateral condylar mandible fractures

Temporomandibular joint (TMJ) function was evaluated following endoscope-assisted transoral open reduction and miniplate fixation of displaced bilateral condylar mandibular fractures. The transoral treatment of bilateral condylar fractures was performed in 13 patients from May 2000 to December 2004. Eleven of the 13 patients had additional mandibular fractures. Out of 26 fractures of the condylar process, 11 were located at the condylar neck and 15 were subcondylar. One, 6 and 12 months after surgery TMJ function was evaluated. Anatomic reduction was achieved using an endoscope-assisted transoral approach even when the condylar fragment was displaced medially and in fractures with comminution. Good TMJ function was noted 6 and 12 months after surgery. Mouth opening was measured to be more than 40 mm without deviation. Postoperative range of motion with a satisfying lateral excursion was found. Early rehabilitation and pre-injury TMJ function was achieved following minimally invasive anatomic fracture reduction.     

Condylar fractures of the mandible. I. Classification and relation to age, occlusion, and concomitant injuries of teeth and teeth-supporting structures, and fractures of the mandibular body.

In 123 individuals, 138 fractures of the mandibular condyle were classified with respect to fracture level, dislocation at the fracture level, and condylar head relation to the articular fossa. The age of the patient and the location of the most distal occlusal contact were recorded as well as teeth injuries and concomitant fractures of the mandibular body. The position of the most distal occlusal contact did not influence the dislocation of the condylar fragment. Teeth injuries such as fractures and luxation were found to be associated with condylar head or neck fractures, whereas the concomitant fractures of the mandibular body were mostly seen with the subcondylar fractures. Teeth injuries as well as concomitant fractures of the mandibular body were found more frequently in patients with bilateral than unilateral condylar fractures. Fractures of teeth in the molar and bicuspid regions were most frequent on the condylar fracture side, while the concomitant fractures of the mandibular body were located to the contralateral side. Medial angulation of the condylar fragment with lateral override at the fracture level was the typical fracture in adults, and angulation without override the characteristic fracture in growing individuals. Medical override occurred both in children and in adults and seemed to be the result of more severe trauma to the chin.     

Unilateral mandibular condylar fractures: a 31-year follow-up of non-surgical treatment

At the University Hospital of Malmö, Sweden, standardized trauma charts were used for registration of all jaw fractures from 1972 to 1976. During the year 2005 the aim was to interview all patients treated non-surgically for unilateral mandibular condylar fractures during this period. In total, 49 patients with unilateral condylar fractures were treated non-surgically in 1972–1976. Of these, 23 patients were available for follow-up, 17 were dead, 7 were not found and 2 did not answer letters or phone calls. The follow-up was a telephone interview according to a standardized questionnaire concerning occurrence of pain and headache, function of the jaw and joint sounds. Information from original records, radiographic reports and the standardized trauma charts revealed fracture site, type of fracture and intermaxillary fixation if any. Eighty-seven percent of the patients reported no pain from the jaws, 83% had no problems chewing and 91% reported no impact of the fracture on daily activities. Neck and shoulder symptoms were reported by 39% and back pain by 30%. The 31-year results of non-surgical treatment of unilateral non-dislocated and minor dislocated condylar fractures seem favourable concerning function, occurrence of pain and impact on daily life.     

Morphological occlusal features following condylar fractures in children

Early fracture of the mandibular condyles may be related to an asymmetric morphologic occlusion. The aim of the study was to investigate the morphologic occlusal symmetry of non-surgically treated children after condylar fractures. The original study group consisted of 55 subjects (31 males and 24 females) who suffered temporomandibular joint condylar fractures at a young age and were treated conservatively, with physiotherapy only. Thirty-two of the respondents who were injured at a mean age of 6.5 years (range 9 months-12 years) comprised the study group. Their occlusion was re-examined intra-orally as well as on study models, at the mean age of 10.5 years (range 2.8-20.7 years). Of these, 21 suffered unilateral and 11 bilateral condylar fractures. The control group comprised a random population of 705 school children. The chi-square test was used for statistical comparison. The general distribution of occlusal patterns (Angle) differed significantly in the study group and in the controls. From the asymmetric occlusal features, only the lower midline deviation was found to be slightly more prevalent in the injured group, with almost perfect coincidence of the side of the fracture and the direction of the lower midline deviation. No significant differences were found in the distribution of posterior crossbite, anterior crossbite, and Class II subdivision in the two groups. Among children who experienced condylar fractures, a higher prevalence of malocclusion was diagnosed; the most prominent asymmetric trait was lower midline deviation coinciding with the side of the unilateral fractured condyle.     

偏侧咀嚼对张闭口运动的影响

目的:分析偏侧咀嚼患者在最大张闭口运动中的下颌运动轨迹特征。方法:通过下颌运动轨迹描记检测技术,比较偏侧咀嚼和正常咀嚼人群在大张口运动中的运动轨迹,进行统计分析。结果:1)偏侧咀嚼组在大张口运动时开闭口轨迹多数分离,开口型与与双侧咀嚼组相比差异有统计学意义(P<0.05)。2)偏侧咀嚼组张闭口运动时垂直向和矢状向位移显著低于双侧咀嚼组(P<0.01)。结论:最大张闭口运动中偏侧咀嚼组开口型多数偏向工作侧,50%的人群开闭口轨迹分离,开口度减小,说明长期偏侧咀嚼会导致张闭口运动轨迹的异常。     

髁状突骨折致颞下颌关节慢性创伤性关节炎的临床观察

目的 初步探讨髁状突骨折致颞下颌关节慢性创伤性关节炎的一般规律.方法 髁状突骨折致慢性创伤性关节炎病例32例.对此组病例的临床、影像学表现等资料进行分析.结果 23例(23/32,71.8%)存在开口受限,7例(7/32,21.9%)有单纯关节弹响,2例(2/32,6.3%)为关节单纯疼痛;22例单侧髁状突骨折中5例(5/22,22.7%)对侧关节逐渐发生轻重不等骨关节病.结论 髁状突骨折经治疗后遗留的慢性创伤性关节炎,其临床表现为关节运动受限、疼痛、弹响等,且以关节运动受限为主.单侧髁状突骨折病例,其未骨折侧亦可发生损伤性病变.     

髁突形态与髁突矢状骨折发生率之间的关系分析

目的：分析髁突形态与单侧髁突矢状骨折(sagittal fracture of mandibular condyle, SFMC)发生率之间的关系。方法：回顾2010年12月—2021年12月河北医科大学第三医院收治的155例单侧髁突矢状骨折患者的病例资料,将其螺旋CT数据以DICOM格式导入RadiAnt DICOM Viewer软件。根据Yale的髁突形态的分类标准,将髁突形态分为平、凸、角、圆4种。根据Hlawitschka的髁突矢状骨折分类标准,将髁突矢状骨折分为A、B、M 3类,分析髁突形态与单侧髁突矢状骨折发生率之间的关系。采用SPSS 26.0软件包对数据进行统计学分析。结果：155例患者中,健侧髁突形态占比分别是平形41.9%、凸形37.4%、圆形11.6%、角形9.0%,髁突矢状骨折的分类占比分别是A型20.6%、B型42.6%、M型36.8%。不同髁突形态的髁突矢状骨折发生率不同,两者之间存在相关性(P=0.015)。平形髁突相比其他3种类型的髁突更容易发生矢状骨折,角形髁突最不容易发生矢状骨折。结论：髁突形态不同会影响髁突矢状骨折发生率,平形髁突更容易发生髁突矢状...     

单侧后牙反者髁突侧向运动轨迹的研究

目的通过记录单侧后牙反者与正常者下颌侧向运动时髁突在三雏方向上的运动轨迹。探讨单侧后牙反者髁交侧向运动轨迹的特征。揭示其与正常之间的差异。方法正常15例,单侧后牙反7例．应用计算机化的髁突运动轨迹描记仅(computer-Aide,Axiography,CADlAX)Ⅰ型以及分析软件(Gamma Dental Sofrware for Windows 2．3．2．22。GDSW)记录下颌做左右侧向运动时髁突在水平面及矢状面上的运动轨迹。结果实验组侧向运动中非工作侧矢状向最大位移量王著小于正常对照组。工作侧髁突向后运动的幅度大于正常对照组。结论单侧后牙反者髁突侧向运动轨迹形态与正常有明显差异。其两侧关节囊、韧带松驰。     

Masticatory muscle function after unilateral condylar fractures: a prospective and quantitative electromyographic study

Electromyographic (EMG) recording of masticatory muscle activity was performed in 9 adult men with unilateral condylar fracture immediately after conservative treatment of the condylar fracture (TO) and 4 (T1) and 8 (T2) months after the trauma. From TO to T2, maximal voluntary contraction of the anterior and posterior temporal muscles and of the masseter muscle opposite the fracture side (contralateral) increased significantly. Activity in the anterior temporal muscles also rose significantly during natural chewing, whereas the masseter muscles remained at the same level, but activity consistently tended to be strongest contralaterally to the condylar fracture. In addition, there was a tendency from T1 to T2 for natural chewing to take place predominantly on the contralateral side. The most obvious overall changes during the follow-up were shorter and stronger contractions in all muscles during chewing, on the side of the impaired joint. The increase of activity in the anterior temporal muscles during maximal bite and natural chewing, and the occurrence of stronger and shorter contractions during ipsilateral chewing, were interpreted as signs of improved function due to healing and relief of pain from the impaired joint. On the other hand, there was a specific rise of maximal activity only in the contralateral masseter. and during natural chewing, activity was constantly stronger in the same muscle in combination with the tendency of increasing predominance of contralateral strokes. These traits specificly related to the masseter muscles were considered an indication of a permanent functional distortion due to reflex suppression on the fracture side as an after-effect of the injury.     

克氏针治疗下颌骨髁突矢状骨折13例回顾性分析

目的探讨克氏针内固定方式在下颌髁突矢状骨折治疗中的应用价值。方法回顾分析2019年1月至2020年1月在广州中医药大学附属佛山市中医院口腔医疗中心就诊的下颌骨髁突矢状骨折复位后采用克氏针内固定治疗的患者,共13例19侧。治疗过程包括常规手术切开、暴露并复位游离的下颌骨髁突后,根据下颌骨髁突骨质断端情况利用2~4根克氏针固定,伴发其他部位骨折时同期手术治疗。术后1周通过CBCT评估游离的下颌骨髁突复位精准度及稳固性,通过临床检查评价咬合关系、开口度、开口型。结果所有患者骨折断端对位良好,克氏针无扭曲、折断和松脱;术后咬合关系、开口度、开口型恢复良好。结论克氏针治疗下颌骨髁突矢状骨折效果确切,有临床应用价值。     

Open Reduction and Rigid Internal Fixation of Mandibular Condylar Fractures by an Intraoral Approach: A Long-Term Follow-Up Study of 15 Patients

PURPOSE: To evaluate the long-term results obtained with open reduction and rigid internal fixation of mandibular condylar fractures by an intraoral approach. PATIENTS AND METHODS: Fifteen patients with 24 mandibular condylar fractures were retrospectively examined with an average follow-up of 23 months (range, 6-63 months). Clinical and radiographic examination was conducted according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), including an evaluation of maximum voluntary bite force measurements and facial nerve function. Statistical analysis was performed on maximum voluntary bite force measurements and maximum pressure pain threshold. RESULTS: Two patients fulfilled the criteria for a RDC/TMD diagnosis. Myofacial pain (group I) and bilateral arthralgia (group III), combined with a moderate nonspecific physical symptom score, was diagnosed in 1 patient and 1 patient received a diagnosis of disc displacement with reduction (group II). Satisfying radiographic fracture healing was seen in 12 joints. However, miniplate fracture occurred in 3 patients and severe bone resorption of the condylar head was seen in one patient. Minor adjustment of the postoperative occlusion was necessary in 6 patients. No significant difference between maximum voluntary isometric bite force measurements or maximum pressure pain threshold was found between the fracture side and the opposite side in unilateral cases or between the operated and nonoperated side in bilateral cases. None of the patients showed facial nerve injury or visible facial scars. CONCLUSION: Within the limitations of a retrospective study, the present study emphasized that optimal management of dislocated bilateral condylar injuries combined with other fractures of the facial skeleton constitute a challenging issue in maxillofacial trauma. Moreover, open reduction and rigid internal fixation of mandibular condylar fractures by an intraoral approach is a technically demanding surgical procedure associated with a high risk of postoperative complications in these injuries.     

Conservative treatment of unilateral condylar fractures in children: a long-term clinical and radiologic follow-up of 55 patients

The purpose of this prospectively designed study was the long-term clinical and radiological evaluation of conservatively treated unilateral condylar fractures in children. Fifty-five children aged between 2 1/2 and 9 3/4 years, presenting with a singular unilateral fracture of the mandibular condyle, were treated in a nonsurgical-functional way using an intraoral myofunctional appliance. In the follow-up period, patients were investigated by standardized clinical examination and by evaluation of panoramic radiographs taken immediately post-traumatically, after 6, 12, 24, 48 and 72 weeks, and then yearly through the period of growth. With a satisfactory clinical course in all patients, there was no instance of functional disturbance or mandibular asymmetry after the respective follow-up periods. The radiographs showed a fairly good shape of the condyle (no or only slight condylar deformity) in the 47 patients of the 2-6 year age group. In the eight patients of the 7-10 year age group presenting with a class II or III condylar fracture, healing was characterized by incomplete condylar regeneration, resulting in a moderate condylar deformity in two cases, a definite reduction in condylar neck height in two cases, and a hypertrophic condylar deformity in four cases. The positive results of this study confirm the concept of a nonsurgical-functional approach in children presenting with various types of unilateral fractures of the mandibular condyle. Condylar remodeling was the mode of fracture healing in instances of displaced and dislocated condylar fractures.     

Dental injuries in association with mandibular condyle fractures

Abstract A total of 356 patients with mandibular condyle fractures were studied regarding associated dental injuries. One third of the patients had injured teeth, on average, 3.7 teeth had been injured per accident. Dental traumas were distributed equally between the anterior (incisors and canines) and posterior teeth (premolars and molars) in both jaws. In unilateral condylar fracture cases maxillary dental injuries involved more often premolars and/or molars of the fracture side than those of the non-fracture side. The mean number of dental traumas in the mandible was higher in cases of simultaneous mandibular body fracture than without, whereas the presence of mandibular body fracture did not affect number of associated dental injuries in the maxilla. The dental injuries were mostly to hard tissue (78%), which were commonest in men, 20 to 29 years of age, and in victims of violence or fall accidents. Severe dental injuries in association with mandibular condyle fractures were more common in accidents due to traffic and miscellaneous causes than in those due to violence. Severe dental injuries were more often encountered when simultaneous mandibular body fracture was present than when it was not and more so in bilateral than unilateral condylar fracture cases. The most important factor correlating with the severity of dental injuries was the presence of bilateral condylar fracture.     

Temporomandibular joint articulations on working side during chewing in adult females with cross‐bite and mandibular asymmetry

Influence of mandibular asymmetry and cross‐bite on temporomandibular joint (TMJ) articulation remained unknown. This study aimed to investigate whether/how the working‐side condylar movement irregularity and articular spaces during chewing differ between patients with mandibular asymmetry/cross‐bite and control subjects. The cross‐bite group and the control group consisted of 10 adult female patients and 10 adult female subjects, respectively. They performed unilateral gum‐chewing. The mandibular movements were recorded using a video‐based opto‐electronic system. The 3D articular surface of the TMJ for each individual was reconstructed using CT/MRI data. For local condylar points, the normalised jerk cost (NJC) towards normal direction to the condylar surface, the angle between tangential velocity vector and condylar long axis and intra‐articular space were measured. Three rotatory angles at centre of the condyle were also measured. During closing and intercuspation, (i) movements of posterior portion of the deviated side condyle showed significantly less smoothness as compared with those for the non‐deviated side and control subjects, (ii) the rotations of the condyle on the deviated side induced greater intra‐articular space at posterior and lateral portions. These findings suggest that chewing on the side of mandibular deviation/cross‐bite may cause irregular movement and enlarged intra‐articular space at posterior portion of the deviated side condyle.