成人下颌偏斜患者下颌髁突三维CT形态对称性研究

目的:建立成人下颌偏斜患者CT三维重建模型,测量、分析髁突形态、三维特征,并比较双侧髁突对称性,为下颌偏斜患者临床诊断、治疗提供参考.方法:对20例下颌偏斜患者(18～30岁)的头颅进行螺旋CT扫描,在Mimics 8.13软件工作站上进行三维图像重建和参数测量,对结果进行统计学分析.结果:偏斜对侧髁突高度较偏斜侧增大(P＜0.05);髁突内外径较偏斜侧增大(P＜0.01);髁突后斜面长度、髁突后斜面倾斜角较偏斜侧减小(P＜0.01).结论:下颌偏斜可引起髁突的非对称性改建,故下颌偏斜患者双侧髁突形态不对称.     

Temporomandibular synovial fluid pressure response to altered mandibular positions

Hydrostatic synovial fluid pressure within the superior aspect of the temporomandibular joint space of the growing pig, Sus scrofa domesticus, was examined in response to various acute and chronic alterations of mandibular position. Bilateral measurements of pressure were recorded with chronically implanted wick catheters in three 8-week-old pigs before and at the time of appliance placement and then at 2-day intervals until the animals were 20 weeks old. Besides confirming the observations of a previous study, we noted that forward positioning of the mandible caused an increase in synovial fluid pressure that decayed to baseline levels within 2 hours. Posterior positioning of the mandible effected a larger increase in pressure that partially decayed over 2 hours but did not return to baseline levels over the entire course of the experiment. These results may have significance in the understanding of the physiology of the temporomandibular joint, local control mechanisms involved in the normal and treatment-aided growth of the mandible, and disorders of the temporomandibular joint.     

Temporomandibular joint symptoms and disc displacement in patients with mandibular prognathism

Our objective was to find out the incidence of signs and symptoms of temporomandibular joint (TMJ) and disc displacement in patients with mandibular prognathism. Fifty-one patients were examined clinically and by axial computed tomography(CT). The incidence of TMJ signs and symptoms was 6/25(24%) in patients with simple mandibular prognathism and 12/26(46%) in patients with mandibular prognathism and asymmetry. No discs were displaced in patients with simple mandibular prognathism, but 15(58%) of the patients with mandibular prognathism and asymmetry had displaced discs. There was no association between signs and symptoms of TMJ and disc displacement. Patients with mild protrusion and severe asymmetry of the mandible had a high incidence of disc displacement, which interestingly was on the deviated side in 14 of the 15 patients affected. We conclude that skeletal morphology may have a role in the development of TMJ disorders but the mechanism is obscure.     

Soft tissue response to mandibular advancement using 3D CBCT scanning

This prospective longitudinal study assessed the 3D soft tissue changes following mandibular advancement surgery. Cranial base registration was performed for superimposition of virtual models built from cone beam computed tomography (CBCT) volumes. Displacements at the soft and hard tissue chin (n = 20), lower incisors and lower lip (n = 21) were computed for presurgery to splint removal (4-6-week surgical outcome), presurgery to 1 year postsurgery (1-year surgical outcome), and splint removal to 1 year postsurgery (postsurgical adaptation). Qualitative evaluations of color maps illustrated the surgical changes and postsurgical adaptations, but only the lower lip showed statistically significant postsurgical adaptations. Soft and hard tissue chin changes were significantly correlated for each of the intervals evaluated: presurgery to splint removal (r = 0.92), presurgery to 1 year postsurgery (r = 0.86), and splint removal to 1 year postsurgery (r = 0.77). A statistically significant correlation between lower incisor and lower lip was found only between presurgery and 1 year postsurgery (r = 0.55). At 1 year after surgery, 31% of the lower lip changes were explained by changes in the lower incisor position while 73% of the soft tissue chin changes were explained by the hard chin. This study suggests that 3D soft tissue response to mandibular advancement surgery is markedly variable.     

Repair processes of experimental root fractures in rat molars examined by histopathological techniques and 3D micro-CT imaging

AimsThe purpose of this study was to investigate the repair processes of experimental intra-alveolar root fractures of immature rat molars with histopathological techniques and 3-dimensional micro-computed X-ray tomography (3D micro-CT) imaging.MethodsTwelve left upper first molars of 4-week-old rats were dislocated toward the palate with modified Hoe's pliers at a load of 900 g for 20 s, and repositioned. After 1 or 2 weeks, the maxillae were dissected and scanned with micro CT for 3D micro-CT imaging. After standard histological preparation, buccolingual serial sections of the maxillae were stained with hematoxylin and eosin or Masson–Goldner stain and observed by light microscopy. Subsequently, we examined the identified root fracture lesions by 3D micro-CT imaging and histopathological sections.ResultsWe identified 6 intra-alveolar vertical incomplete fracture lines in the mesial roots. Histopathological findings showed that newly differentiated odontoblast-like cells had formed immature reparative dentin on the pulpal side of the fracture line at 1 postoperative week, and deposited reparative dentin with a tubular structure at 2 weeks. While surface resorption and granulation-tissue formation occurred on the periodontal side of the fracture line, the narrow fracture line remained unchanged, and the surface resorption lacunae were partly covered with cementum at postoperative 2 weeks.ConclusionsRoot-fracture investigation requires a combination of histopathological observation and 3D-CT imaging. Intra-alveolar fractured root repair accompanied by tubular reparative dentin formation at the pulpal side, and the deposition of cementum at the periodontal side, may occur when the fracture line is too narrow for the formation of granulation tissue.     

成人骨性下颌偏斜患者与正常人下颌骨及颞下颌关节单光子发射型CT/CT同机融合骨显像的比较研究

目的 采用单光子发射型(single-photo Emission CT,SPECT)CT/CT同机融合骨显像技术对成人骨性下颌偏斜患者与正常人下颌骨及颞下颌关节的生长差异进行比较研究.方法 选取成人骨性下颌偏斜患者20例和正常成人志愿者15例,进行SPECT/CT同机融合骨扫描检查,以分析比较下颌偏斜患者与正常人两侧下颌骨及颞下颌关节骨血流和骨代谢的差异性.结果 成人骨性下颌偏斜患者下颌骨不同部位的骨血流和骨代谢存在特定性差异,正常人下颌骨不同部位的骨血流和骨代谢存在特定性差异;正常人下颌骨不同部位左右两侧放射性计数值比值均接近于1,对称性较好;与正常对照组相比,骨性下颌偏斜患者放射性强度均为对侧高于偏斜侧;髁状突差异最大(P＜0.01),其次为下颌角(P＜0.01),下颌升支中份差异最小(P＜0.05);不同部位两侧差异均有统计学意义.结论 SPECT/CT同机融合骨显像在精确解剖定位的基础上,能更加准确显示颞下颌关节的功能变化.

Abstract：

Objective To investigate mandible and temporomandibular joint (TMJ) in adults with and without mandible deviation using SPECT/CT fusion imaging. Methods SPECT/CT fusion imaging over bilateral mandible and TMJ was performed in 20 adult patients with mandibular deviation and 15 adult volunteers without mandibular deviation. Results Compared with the control group, the radioactive intensity of contralateral side was higher than that of the deviated side in patients with mandibular deviation. The biggest difference was found in the condyle process (P＜0. 01) and the mandibular angle (P＜0. 01). Conclusions Based on accurate anatomical localization, SPECT/CT fusion imaging was very sensitive in detecting functional alteration in TMJ.     

成人骨性下颌偏斜患者与正常人下颌骨及颞下颌关节单光子发射型CT/CT同机融合骨显像的比较研究

Objective To investigate mandible and temporomandibular joint (TMJ) in adults with and without mandible deviation using SPECT/CT fusion imaging. Methods SPECT/CT fusion imaging over bilateral mandible and TMJ was performed in 20 adult patients with mandibular deviation and 15 adult volunteers without mandibular deviation. Results Compared with the control group, the radioactive intensity of contralateral side was higher than that of the deviated side in patients with mandibular deviation. The biggest difference was found in the condyle process (P＜0. 01) and the mandibular angle (P＜0. 01). Conclusions Based on accurate anatomical localization, SPECT/CT fusion imaging was very sensitive in detecting functional alteration in TMJ.     

Temporomandibular joint comparative imaging: diagnostic efficacy of arthroscopy compared to tomography and arthrography

This comparative imaging study of the TMJ was conducted to examine the diagnostic data obtained from arthroscopy as compared to data from tomography and arthrography. Six joints from cadaver material were imaged by each technique and subsequently dissected. Each technique had value, but none was comprehensive. Tomography was the technique of choice for imaging osseous changes. Double joint space arthrotomography was useful for examining articular disk position and morphology. Diagnostic arthroscopy, through direct visualization of surface morphology, showed localized surface pathosis, such as synovitis; provided data on the location and size of disk perforations; and contributed reliably to a diagnosis of disk displacement on the basis of associated pathosis such as stretching of the posterior attachment.     

Quantification of the mandibular defect healing by micro-CT morphometric analysis in rats

Purpose

The goal of this study was the evaluation of the bone tissue structural characteristics over the time course of mandibular defect healing using micro-CT technique, as well as determination of the inter-relationships between different micro-CT parameters used for assessment of the bone regeneration process and the patterns of their dynamic changes.

Temporomandibular joint and masticatory muscle involvement in myotonic dystrophy: a study by magnetic resonance imaging

OBJECTIVE: The purpose of this study was to evaluate the masticatory muscles and the temporomandibular joint (TMJ) by magnetic resonance imaging (MRI) in myotonic dystrophy (MD) patients. STUDY DESIGN: MRI of the masticatory muscles and TMJ was performed in 15 MD patients, 11 male and 4 female, aged 16 to 53 years (mean, 31 years). Many of them had dental malocclusion, especially Angle class III and anterior open bite, and 3 complained of recurrent TMJ dislocation. TMJ and masticatory muscle pain was not observed, and joint sounds were noted in only 1 patient. RESULTS: The analysis of MRI scans showed masticatory muscle involvement in 13 patients (86.6%). In 11, the involvement was moderate to intense. The main abnormalities observed were increased intramuscular tissue signal on T1 (fatty infiltration) and volumetric reduction of muscles. Regarding the TMJ, articular disk displacement was seen in only 1 patient, but abnormalities of disk shape were common. Mild bone abnormalities were frequently observed, including changes of shape and contour of bone surface, and sclerosis of bone marrow. In 4 patients the condyle moved anterior to the eminence with the mouth opened fully (condylar hyperexcursion). CONCLUSIONS: This study shows that masticatory muscles are frequently and intensively affected in MD patients. Bone changes are the most consistent abnormalities observed in the TMJ. It is possible that remodeling is caused by biomechanical changes in the jaw as a result of masticatory muscle involvement.     

偏突颌患者颞下颌关节盘冠状向位置的MRI评估

目的研究偏突颌畸形患者双侧颞下颌关节盘-髁突位置在冠状位磁共振图像(magnetic resonance imaging,MRI)上的差异,并分析其关节盘移位程度与偏斜严重程度的相关性。方法对54例骨性Ⅲ类错患者进行标准化临床影像学检查得到闭口斜冠状位MRI,通过计算机软件测量分析其冠状位关节盘内外侧移位情况,应用wilcoxon秩和检验分析各组间颞下颌关节盘-髁位置在冠状位磁共振图像上的差异。结果40例偏突颌畸形患者中,偏斜侧7侧(17.5%)关节盘外侧移位,16侧(40.0%)内侧移位;而40侧偏斜对侧关节盘中,27侧(67.5%)关节盘内侧移位,仅2侧(5.0%)关节盘向外侧移位。14例(28侧)无偏斜骨性Ⅲ类患者中,18侧(64.3%)存在关节盘内侧移位,未发现外侧移位的关节盘。本研究证实了偏斜侧关节盘内外侧位置与偏斜对侧及无偏斜组存在显著性差异(P<0.05),中等到重度偏突颌患者偏斜侧关节盘位置与轻度及无偏斜者之间的差异具有统计学意义(P<0.05)。结论在冠状位磁共振图像中显示,中等到重度偏突颌患者偏斜侧关节盘倾向于向外侧移位,偏斜对侧关节盘倾向于向内侧移位。     

Histological changes in the temporomandibular joint in rabbits depending on the extent of mandibular lengthening by osteodistraction

We studied the histological changes in the temporomandibular joint (TMJ) after unilateral mandibular distraction osteogenesis in rabbits. Eight rabbits were used, two of which served as controls and the other six had distraction of the left mandibular body after a latency period of 7 days at a rate of 0.5mm a day for a total of 2mm (n = 2), 3.5mm (n = 2), and 5mm (n = 2) of distraction. After a 14-day consolidation period, TMJs from both sides were harvested and prepared for histological examination under an optical microscope using haematoxylin and eosin stain. We found no degenerative or inflammatory changes in either TMJ in any of the groups. Endochondral ossification in the condyle was greater on the opposite side in the experimental group than in the condyles of the control group. Endochondral ossification was active in the 3.5-mm group.     

Temporomandibular joint sounds: correlation to joint structure in fresh autopsy specimens.

In an attempt to better understand the cause of different types of temporomandibular joint (TMJ) sounds, we recorded joint sounds from 27 fresh autopsy specimens, displayed the time frequency distribution of the sound as a three-dimensional graph, and correlated the sound character to morphologic observations at subsequent dissection. Eleven joints elicited sounds, and 16 joints were silent. All joints with sounds had different degrees of intraarticular changes. These ranged from disk displacement with reduction to displacement without reduction and arthrosis of the articular surfaces. Reciprocal clicking occurred both in joints with disk displacement with and without reduction, as well as in joints with arthrotic changes. Crepitation only occurred in joints with arthrosis and perforation. The sample was too small to demonstrate any statistically significant association between the joint sound classified as clicking or crepitation and joint structure types of joint pathosis in this small sample. A high frequency component to the sound appeared to be associated with arthrosis of the articular surfaces. It was concluded that joint sounds indicate joint abnormality but that the absence of joint sound does not exclude intraarticular pathosis.     

Changes in temporomandibular joint morphology in class II patients treated with fixed mandibular repositioning and evaluated through 3D imaging: a systematic review

To estimate the effects of skeletal class II malocclusion treatment using fixed mandibular repositioning appliances on the position and morphology of the temporomandibular joint (TMJ). Two independent reviewers performed comprehensive electronic searches of MEDLINE, EMBASE, EBM reviews and Scopus (until May 5, 2015). The references of the identified articles were also manually searched. All studies investigating morphological changes of the TMJ articular disc, condyle and glenoid fossa with 3D imaging following non‐surgical fixed mandibular repositioning appliances in growing individuals with class II malocclusions were included in the analysis. Of the 269 articles initially reviewed, only 12 articles used magnetic resonance imaging and two articles used computed tomography (CT) or cone‐beam CT images. Treatment effect on condyle and glenoid fossa was discussed in eight articles. Treatment effect on TMJ articular disc position and morphology was discussed in seven articles. All articles showed a high risk of bias due to deficient methodology: inadequate consideration of confounding variables, blinding of image assessment, selection or absence of control group and outcome measurement. Reported changes in osseous remodelling, condylar and disc position were contradictory. The selected articles failed to establish conclusive evidence of the exact nature of TMJ tissue response to fixed mandibular repositioning appliances.     

利用CBCT对不同年龄组下颌偏斜患者髁突进行的三维形态研究

目的建立不同年龄组下颌偏斜患者CT三维重建模型,测量、分析不同年龄组下颌偏斜患者髁突形态三维特征,并比较双侧髁突对称性。方法选择3个不同年龄组:替牙组(8～11岁)和年轻恒牙列组(11～16岁),成人组(18～30岁)的偏颌患者各12例,进行CBCT扫描,采集颅面部DICOM数据,使用Sim plant对骨组织进行三维重建和参数测量,对结果进行统计学分析。结果不同年龄组偏颌患者髁突三维形态存在差异性。替牙组下颌偏斜患者两侧髁突形态无明显差异;年轻恒牙列组髁突高度、髁突内外径、下颌支高度、髁突后斜面长度、髁突后斜面倾角偏斜侧与对侧比较出现了差异,双侧髁突形态发生了非对称性改变;成人组下颌偏斜患者双侧髁突形态发生了明显的非对称性改变,偏斜对侧髁突高度、下颌升支高度、髁突内外径较偏斜侧增大,髁突后斜面长度、后斜面倾斜角较偏斜侧减小。结论下颌偏斜可引起髁突的非对称性改建,从替牙组到成人组,下颌偏斜有从下颌移位向骨骼异常发展的趋势,故下颌偏斜患者应该早期矫治。     

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.