The effects of TMJ symptoms on skeletal morphology in orthodontic patients with TMJ disc displacement

Objective. The aim of this study was to investigate the effects of temporomandibular joint (TMJ) symptoms on skeletal morphologies of orthodontic patients with TMJ disc displacement (DD). Materials and methods. The sample consisted of 197 women seeking orthodontic treatment. The subjects were divided into two groups according to the presence of TMJ symptoms: the presence and absence of TMJ symptoms. Each group was sub-divided into three groups based on magnetic resonance images of bilateral TMJs: bilateral normal disc position (BN), bilateral disc displacement with reduction (DDR) and bilateral disc displacement without reduction (DDNR). Seventeen variables from lateral cephalograms were analyzed by two-way analysis of variance to identify differences in skeletal morphologies with respect to TMJ symptoms and TMJ DD status. Results. Patients with TMJ DD were more likely to have short ramus height, short mandibular body length and backward positioning of the ramus and mandible. These skeletal morphologies became more severe as TMJ DD progressed to DDNR. However, the skeletal morphologies associated with TMJ DD were not significantly different between symptomatic and asymptomatic patients. As a result, patients with TMJ DD had backward positioning and clockwise rotation compared to those with bilateral normal TMJs, irrespective of the presence of TMJ symptom. Conclusions. This study suggests that TMJ DD is associated with altered skeletal morphology, but TMJ symptoms do not significantly influence the relationships between TMJ DD and skeletal morphology.     

Magnetic resonance imaging-verified temporomandibular joint disk displacement in relation to sagittal and vertical jaw deformities

This retrospective study was designed to analyze the relationships between temporomandibular joint (TMJ) disk displacement and skeletal deformities in orthodontic patients. Subjects consisted of 460 adult patients. Before treatment, lateral cephalograms and TMJ magnetic resonance imaging (MRI) were recorded. Subjects were divided into six groups based on TMJ MRI according to increasing severity of TMJ disk displacement, in the following order: bilateral normal TMJs, unilateral disk displacement with reduction (DDR) and contralateral normal, bilateral DDR, unilateral disk displacement without reduction (DDNR) and contralateral normal, unilateral DDR and contralateral DDNR, and bilateral DDNR. Subjects were subdivided sagittally into skeletal Class I, II, and III deformities based on the ANB (point A, nasion, point B) angle and subdivided vertically into hypodivergent, normodivergent, and hyperdivergent deformities based on the facial height ratio. Linear trends between severity of TMJ disk displacement and sagittal or vertical deformities were analyzed by Cochran–Mantel–Haenszel test. The severity of TMJ disk displacement increased as the sagittal skeletal classification changed from skeletal Class III to skeletal Class II and the vertical skeletal classification changed from hypodivergent to hyperdivergent. There were no significant differences in the linear trend of TMJ disk displacement severity between the sexes according to the skeletal deformities. This study suggests that subjects with skeletal Class II and/or hyperdivergent deformities have a high possibility of severe TMJ disk displacement, regardless of sex.     

Relationship between internal derangement of the temporomandibular joint and dentofacial morphology in women with anterior open bite.

INTRODUCTION: Anterior open bite is known to be associated with internal derangement of the temporomandibular joint (TMJ). This study examined the relationships between internal derangement and dentofacial morphology in women with anterior open bite. METHODS: Fifty-one women with anterior open bite were enrolled in this study. The sample was divided into 3 groups based on magnetic resonance imaging of bilateral TMJs: normal disk position, disk displacement with reduction, and disk displacement without reduction. One-way analysis of variance was used to compare the 3 groups with respect to the cephalometric variables, and Duncan's multiple comparisons were performed at the 95% confidence level to identify the differences among the 3 groups. RESULTS: Internal derangement of the TMJ was much more prevalent in subjects with a more posteriorly rotated mandibular ramus, a smaller mandible, and a greater tendency for a skeletal Class II pattern, although all subjects had an anterior open bite. These patterns were more severe as the internal derangement progressed to disk displacement without reduction. CONCLUSIONS: Some cephalometric characteristics, such as a decrease in posterior facial height, decrease in ramus height, and backward rotation and retruded position of the mandible, are associated with TMJ internal derangement in women with anterior open bite.     

Cephalometric keys to internal derangement of temporomandibular joint in women with Class II malocclusions.

The aim of this study was to find cephalometric keys to provide information on the progression of temporomandibular internal derangement. The sample consisted of 58 women with Class II malocclusions. They were examined with routine lateral cephalograms and magnetic resonance imaging of the temporomandibular joint (TMJ) before orthodontic treatment. They were classified into 3 groups according to the results of the magnetic resonance imaging: normal disk position, disk displacement with reduction, and disk displacement without reduction. Thirty-four cephalometric variables regarding their pretreatment lateral cephalograms were analyzed by 1-way analysis of variance to evaluate the differences in the dentofacial morphology among the 3 groups. The results showed a decrease in posterior facial height, a decrease in ramus height, and backward rotation and retruded position of the mandible in the subjects with internal derangement of the TMJ. These changes were less severe in those with disk displacement with reduction and more severe as internal derangement progressed to disk displacement without reduction. The results suggest that internal derangement of the TMJ might induce dentofacial changes, and that some cephalometric variables can assist in identifying potential patients with internal derangement of the TMJ.     

Longitudinal study on TMJ disk status and its effect on mandibular growth

Abstract

Objective: This longitudinal study assessed the potential contribution of temporomandibular joint (TMJ) disk status over mandibular linear and angular changes.

Design: Cohort study.

Setting: Edmonton, Alberta, Canada.

Participants: Seventy-three adolescent subjects attending TMJ or orthodontic clinics with or without TMJ disk abnormality were followed during a mean 3 years 7 months. From this sample 39 subjects underwent orthodontic treatment.

Methods: Disk displacement and disk length measurements taken from MRIs were utilized to evaluate the TMJ disk status. Mandibular changes were quantified from cephalometric radiographs by superimposing the mandible around the internal cortex of the posterior wall of the mandibular symphysis. Fishman’s skeletal maturation system was used to calculate the percentage of mandibular growth remaining during the follow-up. This expected mandibular growth was factored out through a statistical normalization process applied to the actual difference between the initial and final mandibular measurements. In addition, previous orthodontic treatment was also considered for the analysis. A multiple analysis of variance (MANOVA) was used to evaluate interaction between the independent variables (TMJ disk status and previous orthodontic treatment) over the dependent variables (mandibular ramus, mandibular body, mandibular length and gonial angle measurements).

Results: No significant contribution was found of any of the evaluated variables or its interactions over the mandibular measurements.

Conclusions: No evidence was found of TMJ disk abnormality as an associated significant factor with mandibular dimensional changes. The findings have to be evaluated with caution because of some limitations identified in this study.     

Dentofacial characteristics in orthodontic patients with centric relation–maximum intercuspation discrepancy

Introduction:To investigate dentofacial characteristics of orthodontic patients with centric relation (CR)–maximum intercuspation (MI) discrepancy and to analyze changes in dentofacial characteristics between CR and MI positions in these patients using lateral cephalograms.Materials and Methods:Adult female patients were classified into two groups: large CR-MI discrepancy (greater than 2.0 mm horizontal or vertical mandibular incisor movements during CR to MI change, n  =  20) and small CR-MI discrepancy (less than 1.0 mm horizontal and vertical mandibular incisor movements during CR to MI change, n  =  22). All subjects underwent temporomandibular joint (TMJ) magnetic resonance imaging prior to treatment. Gnathological stabilizing splints were used to find a reliable CR position in patients with large CR-MI discrepancy. Sixteen variables from lateral cephalograms were analyzed to identify differences in cephalometric variables between CR and MI positions in patients with large discrepancy. Differences in dentofacial cephalometric variables at MI positions between patients with large and small CR-MI discrepancies were also analyzed.Results:Patients with large CR-MI discrepancy had backward positioning and rotation of the mandible at the MI position compared to the norm. In addition, the mandible moved more posteriorly and rotated more in a clockwise direction during MI to CR change. Interestingly, all patients with large CR-MI discrepancy had TMJ disk displacement. There were no significant differences in the cephalometric variables of the MI positions between patients with small and large CR-MI discrepancies.Conclusions:This study suggests that adult patients with backward positioning and rotation of the mandible should be carefully evaluated as a result of the potential CR-MI discrepancy.     

Relationship between temporomandibular joint internal derangement and facial asymmetry in women.

INTRODUCTION: Internal derangement (ID) of the temporomandibular joint (TMJ) can cause facial asymmetry. The purposes of this study were to analyze the relationship between facial asymmetry and TMJ ID by using posteroanterior cephalometric variables, and to compare the findings with the results of magnetic resonance imaging (MRI). METHODS: The sample consisted of women seeking orthodontic treatment at Seoul National University Dental Hospital who had routine posteroanterior cephalograms and bilateral MRIs of the TMJ. To eliminate the influence of condylar hyperplasia on facial asymmetry, only those with SNB angles less then 78 degrees were selected (n = 63). They were classified into 5 groups according to the results of the MRI: bilateral normal disk position, unilateral normal TMJ and contralateral disk displacement with reduction (DDR), bilateral DDR, unilateral DDR and contralateral disk displacement without reduction (DDNR), and bilateral DDNR. Fourteen variables from posteroanterior cephalograms were analyzed with 1-way ANOVA to evaluate differences among the 5 groups. RESULTS: Subjects with TMJ ID of greater severity on the unilateral side had shorter ramal height compared with those with bilateral normal or bilateral DDR or bilateral DDNR. In addition, the mandibular midpoint deviated toward the side where the TMJ ID was more advanced. CONCLUSIONS: Subjects with a more degenerated TMJ on the unilateral side might have facial asymmetry that does not come from condylar or hemi-mandibular hyperplasia.     

Bilateral TMJ disk displacement induces mandibular retrognathia

Unilateral non-reducing TMJ disk displacement has been shown to retard mandibular growth on the ipsilateral side, with facial asymmetry a sequela. We hypothesized that bilateral affliction would impair mandibular growth bilaterally, generating mandibular retrognathia. Non-reducing TMJ disk displacement was surgically created in 10 growing New Zealand White rabbits. Ten additional rabbits served as a sham-operated control group. Facial growth was followed in serial cephalograms, with tantalum implants, during a period corresponding to childhood and adolescence in man. The results verified that bilateral non-reducing TMJ disk displacement retarded mandibular growth bilaterally, the extent corresponding to mandibular retrognathia in man. Maxillary growth was also retarded, but to a lesser degree. Growth impairment fluctuated over time, the most striking retardation occurring during periods of general growth acceleration. This should be taken into consideration when orthodontic treatment, aimed at stimulating mandibular growth, is initiated in adolescent individuals with non-reducing TMJ disk displacement.     

伴颞下颌关节病错畸形的正畸治疗原则与方案

颞下颌关节(TMJ)的生物学特征是适应性改建,主要表现为髁突在咬合状态与下颌位置改变时会引发吸收、增生或修复.错畸形类型与颞下颌关节病(TMD)易感性之间存在关联.总体上,错畸形与TMD易感性从高到低依次为:突面、偏颌、直面、凹面错畸形.在突面畸形中,骨源性与混合Ⅱ型的TMD易感性最高,常表现为突吸退(突面畸形-髁突吸...     

Orthodontic finishing after TMJ disk manipulation and recapture

Orthodontic treatment has as its goal in most patients to achieve a cosmetic and functional result. There are functional goals for all orthodontic treatment and in some few cases the functional outweigh the cosmetic; an example would be a cleft-palate case. Orthodontic finishing to a specific condylar position is not routinely a goal of orthodontic care. The reason for this is that only patients who have pain, dysfunction and a negative change in quality of life from their temporomandibular apparatus need this tangential type of treatment. Research has shown that most patients suffering from a temporomandibular disorder (TMD) have displacement of the temporomandibular disk(s). Research has shown that when the mandibular condyle is repositioned to the Gelb 4/7 position that the temporomandibular joint disk is recaptured to a normal position between 85% and 96% of the time. The Gelb 4/7 position has been equated to the physiologic position of the mandibular condyle in the glenoid fossa. TMJ condyle repositioning to the physiologic position has been correlated to disk recapture proven by magnetic resonance imaging (MRI). A case is shown in which a displacement without reduction is manipulated into reduction and maintained with orthodontic correction. TMJ disk displacement without reduction is usually preceded by TMJ disk displacement with reduction. Pumping of the upper joint compartment can assist in reducing the TMJ disk displacement without reduction. Magnetic resonance imaging before and after the manipulation and after orthodontic treatment are shown. A detailed method of orthodontic finishing that maintains a specific condylar position and TMJ disk recapture is shown.     

Condylar bony change and mandibular deviation in orthodontic patients – using helical CT and MRI

This study was designed to assess the relationship between condylar bony change and mandibular deviation in the orthodontic patient. Seventy‐one patients were examined with helical computed tomography and magnetic resonance imaging to assess the condylar bony change and/or disk displacement prior to acceptance for orthodontic treatment. They were grouped into no condylar bony change (NBC) and unilateral condylar bony change (UBC). Frontal and lateral cephalograms and panoramic radiographs were also utilized to evaluate craniofacial morphology, and condylar and ramal heights. The results revealed that TMJ sounds occurred more in the UBC than the NBC group at all ages; but, TMJ pain and difficulty of mouth opening did not show remarkable differences. Erosion, a characteristic feature in age 9–13 years in UBC, occurred with normal disk position or disk displacement without reduction. Flattening exhibited normal disk position in age 9–13 years but was accompanied with disk displacement in age 14–18 years and 19 years and above. Osteophyte formation was highly associated with disk displacement without reduction in all age groups. Moreover, the UBC group's mandible was deviated to the ipsilateral side with significantly shorter condylar height on the affected side. In all age groups of UBC, the difference of condylar height was highly correlated with anterior maxilla, occlusal and gonial planes and with mandibular deviation. All aforementioned results suggest that unilateral condylar bony change can occur with normal disk position or ahead of disk displacement in the young patients. It seems that unilateral condylar bony changes can cause not only mandibular deviation but can also affect the cant of maxillary basal bone, mandibular plane angle and lower dentition.     

双颌手术升支截骨后退术后下颌稳定性及与关节关系的研究

目的　探讨升支矢状劈开截骨术(BSSRO)小钛板坚固内固定与口内入路升支垂直截骨术(BIVRO)下颌后退术后颌稳定性的不同规律,了解导致复发的有关因素特别是髁状突移位在不同手术后复发过程中的意义。方法　升支截骨手术后退下颌的患者共38例,皆为双颌手术,其中下颌BSSRO19例,BIVRO后退术19例。于手术前1周(T1),手术后1周(T2),3个月(T3)及1年(T4)分别拍摄定位头颅侧位片及定位颞下颌关节薛氏位片用于测量下颌移动幅度及关节髁状突的手术后移位。结果　双颌手术下颌升支截骨后退术后,BSSRO坚固内固定组1年时的复发率为25%,而BIVRO组大部分患者1年时下颌发生了与手术目的相同的移动,两组的不稳定主要发生在术后3个月内。结论　手术使髁状突移位术后位置的调整可导致BIVRO术后的下颌继续后移而不稳定,而髁状突近心骨段术中向后旋转术后位置的调整可导致BSSRO术后的下颌骨继续向前而不稳定     

The accuracy of preoperative orthognathic predictions

We assessed the accuracy of preoperative OPAL trade mark orthognathic predictions by retrospective analysis of 25 Class II patients who had had orthodontic treatment combined with mandibular advancement osteotomy. Preoperative and postoperative lateral cephalographs were digitised and surgical predictions generated using OPAL software. Each prediction was compared with the corresponding clinical changes. We also made a method error study by doing a random retracing of 25 cephalographs. Predictions of some of the principal OPAL values (SNA, ANB, LAFH%, OJ, OB) were reasonably accurate in terms of mean values. However, there were large individual variations for most variables and predictions of the vertical skeletal, incisor, and Wits measurements were imprecise. In particular, there was a bias towards under-prediction of the vertical skeletal changes when there was more backward mandibular rotation than anticipated. Immediate postoperative cephalographs were also affected by a 2.1mm mean downward displacement of the mandible as a result of the surgical wafer.     

MRI of TMJ in patients with severe skeletal malocclusion following surgical/orthodontic treatment

The aim of this study was to evaluate temporomandibular joints (TMJ) by magnetic resonance imaging (MRI) in patients who had undergone surgical/orthodontic or orthodontic treatment in a three-year follow-up study. Subjects consisted of 20 patients (40 TMJ), 16 females and four males (mean age 33.7 years, range 19-53 years), with severe temporomandibular disorders (TMD) referred to the Oral and Maxillofacial Department at Oulu University Hospital due to skeletal jaw discrepancy. All patients underwent extensive surgical/orthodontic or orthodontic treatment between 1996 and 2003. Clinical stomatognathic examination and MRI examinations were performed before the surgical/orthodontic or orthodontic treatment and one year after the completion of the treatment. The average treatment time was 23 months (range 12-34 months). MRI revealed a marked decrease, especially in the number of TMJ with joint effusion after the treatment. There were only a few changes in the number of diagnosed disk dislocations before and after the treatment. In five joints with anterior disk dislocation with reduction (r-ADD), a change to anterior disk dislocation without reduction (nr-ADD) was found. In 25 of the 40 condyles, the condylar configuration was normal on MRI before the treatment and in 19 condyles one year after the treatment. TMD signs and symptoms according to the Helkimo dysfunction index showed a statistically significant decrease after the treatment.     

骨性Ⅱ类错伴颞下颌关节紊乱矫正后的长期稳定性

目的:研究骨性Ⅱ类错伴颞下颌关节紊乱患者在正颌-正畸联合治疗后面型和咬合的长期稳定性。方法:选择10例在本院正颌-正畸中心治疗结束3年以上、资料齐全的骨性Ⅱ类错患者,男2例,女8例,平均年龄(22.3±2.9)岁,治疗结束平均随访期(2.63±1.36)a。治疗方案为术前正畸、正颌手术、术后正畸,手术根据面型测量数据采用双颌手术或上颌手术+颏成形,术中采用坚强内固定。比较治疗前(T0)、治疗结束(T1)和随访结束(T2)的X线头影测量数据,评价颞下颌关节(TMJ)症状量表和MRI的变化。采用SPSS16.0软件包分别对治疗前、随访结束与治疗结束的测量数据进行配对t检验。结果:覆盖平均增加0.62mm,有显著性差异,其余骨性、牙性复发和软组织改建无统计学意义;随访结束UI-NA距离、覆盖和覆变化>2mm占10%,Go-Co长度变化>2mm占20%,软组织颏前点的变化量>2mm占40%,LI-NB距离和颏唇沟的深度变化均小于2mm;所有患者关节症状无加重,MRI未见髁突吸收加重,盘髁关系未见明显改变。结论:骨性Ⅱ类错伴TMD患者通过正颌-正畸联合治疗,能获得面型美观和正常的咬合关系,远期面型结构及咬合关系未见明显复发趋势,未发现TMJ症状加重趋势。     

Changes in condylar and joint disc positions after bilateral sagittal split ramus osteotomy for correction of mandibular prognathism

The effect of combined orthodontic and orthognathic treatment was studied retrospectively in 24 patients with skeletal class III malocclusions with mandibular hyperplasia, particularly the effect on temporomandibular joint (TMJ) disc position. The patients underwent preoperative orthodontic treatment, orthognathic surgery, and postoperative orthodontic treatment. The patients were studied clinically, radiographically with lateral cephalometric radiograph and MRI to locate the position of the TMJ disc in relation to the glenoid fossa. One patient had less pain after treatment, one lost abnormal joint clicking sounds after treatment. There were no TMJ symptoms in 20 of the 24 preoperatively and postoperatively. 48 sagittal MRI images showed that the disc length before treatment was 3.040–12.928 (mean 8.289 ± 2.028) and after treatment was 3.699–11.589 (mean 8.097 ± 1.966); results were not significant (p > 0.05). Maximum disc displacement before treatment was 6.090 (mean 1.383), after treatment it was 11.931 (mean 2.193); results were not significant (p > 0.05). The results suggest that combined orthodontic and orthognathic treatment (including bilateral SSRO and rigid internal fixation) can be used safely to correct skeletal class III malocclusion with mandibular hyperplasia without causing additional TMJ symptoms.     

一种新型Ⅲ类磁力矫治器在骨性Ⅲ类患者早期治疗中的作用评价

目的:本研究自主开发了一种新型Ⅲ类磁力Twin-block功能矫形装置（MOA-Ⅲ）,通过对青春前期安氏Ⅲ类错的临床治疗,分析其对青春前期安氏Ⅲ类错患者颅面复合体的作用,探讨其临床矫治机制。方法:应用MOA-Ⅲ矫治器对30例（男12例,女18例）青春前期轻度骨性Ⅲ类错患者进行治疗。另外选取18例（男7例,女11例）未立刻进行治疗并随访半年的患者作为对照组。患者平均初始年龄为9岁3个月,平均治疗时间为6.6个月。利用SPSS15.0软件包,应用t检验对40项相关头颅测量数据进行分析。结果:MOA-Ⅲ可对上、下颌骨间关系的调整起到非常有效的作用。上颌骨发生前移并伴随一定的顺时针旋转,下颌骨则发生轻度的后下旋转。下颌骨体及下颌支长度无显著变化。治疗后上颌前牙发生一定程度唇倾,而下前牙发生一定程度的舌倾。软组织测量显示,上唇前移而下唇发生一定程度的后移。对照组除一些下颌骨及软组织的测量项目发生变化外,其他项目均无显著差异。结论:通过与未进行治疗的对照组进行比较,应用MOA-Ⅲ矫治器对青春前期轻度骨性Ⅲ类错进行治疗是有效的。其矫治结果主要来自上颌骨及上颌牙列的前移及下颌骨的顺时针方向旋转。     

An adolescent case of skeletal maxillary protrusion with osteoarthritis of the temporomandibular joint

This article is designed to report the treatment of an adolescent patient, aged 13 years and 5 months, with maxillary protrusion and temporomandibular joint-osteoarthritis (TMJ-OA). MRI showed anterior disk displacement without reduction in both TMJs and the left condyle revealed a flattened-structure with undefined cortical bone. TMJ pain disappeared 4 months after splint therapy, and the initiation of orthodontic treatment was postponed until the end of pubertal growth. After extraction of the maxillary first premolars, multi-bracket appliances were placed at the aged 16 years and 11 months. After 2.5-year treatment, an acceptable occlusion was achieved without additional clockwise rotation of the mandible. It is emphasized that careful planning is required to avoid any progress in TMJ-OA throughout the treatment for young patients.     

Comparison of skeletal and dental morphology in asymptomatic volunteers and symptomatic patients with bilateral disk displacement with reduction

The purpose of this study was to evaluate the effect of bilateral disk displacement with reduction (BDDR) on the skeletal and dental pattern of affected individuals. There were 42 symptomatic female patients and 46 asymptomatic normal female volunteers. All study participants had bilateral high-resolution magnetic resonance scans in the sagittal (closed and open) and coronal (closed) planes for evaluation of the temporomandibular joints. Linear and angular cephalometric measurements were taken to evaluate the skeletal, denture base, and dental characteristics of the two groups. Analysis of variance was used to compare the symptomatic subjects with the control subjects. The length of both the anterior (S-Na) and posterior (S-Ba) cranial base was smaller in the BDDR group. SNA and SNB angles were also smaller in the symptomatic group. There were also significant differences in the denture pattern. The interincisal angle was larger and the upper incisor was more retroclined in the BDDR group. This study showed that alterations in skeletal morphology may be associated with disk displacement (DD). The mechanisms by which DD is produced or the mechanisms that cause that skeletal alteration are yet to be clarified. This study suggests that subjects with BDDR may manifest altered craniofacial morphology. The clinician should be aware of this possibility especially for the growing patients and the orthognathic surgery candidates.     

Mandibular advancement using an intra-oral osteogenic distraction technique: a report of three clinical cases

Osteogenic distraction has been used for decades to lengthen limbs and now attention is focused upon its use within the craniofacial skeleton. This paper addresses distraction of the mandible. It is proposed that mandibular osteogenic distraction could be a possible adjunct to the orthodontic treatment of those adult patients with skeletal anomalies, who would benefit from combined orthodontic/orthognathic treatment. Three consecutive cases from one unit are presented, where adult patients with severe Class II division 1 malocclusions have undergone orthodontic treatment combined with mandibular osteogenic distraction, instead of conventional bilateral sagittal split osteotomies.