单侧后牙反患者髁状突及下颌升支对称性的螺旋CT研究

目的:探讨单侧后牙反成年患者髁状突及下颌升支的对称性。方法:对22例单侧后牙反患者进行螺旋CT扫描、多层面重建和相关参数测量,并进行统计分析。结果:双侧髁突内、外突点的距离,髁突内倾角及下颌角点的距离有显著差异,但髁突左右径、髁状突最大横截面积、下颌支高度及下颌支冠状位最大面积的差异无统计学意义。结论:单侧后牙反患者左右侧髁状突及下颌支的位置不对称,但髁突及下颌升支大小无显著差异。     

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。     

单侧完全性唇腭裂患者髁突及下颌升支对称性的锥形束CT研究

目的: 评价单侧完全性唇腭裂(UCLP)患者下颌骨髁突及升支垂直向对称性。方法: 取25例单侧完全性唇腭裂患者作为实验组,25例同年龄正常牙合人群作为对照组,两组均拍摄锥形束CT(CBCT)图像,对下颌髁突高度(CH)、升支高度(RH)及髁突与升支高度和(CH+RH)进行测量分析及不对称指数计算,所得数据使用SPSS17.0进行配对样本t检验和独立样本t检验。结果: 单侧完全性唇腭裂患者健侧与患侧下颌髁突高度、髁突与升支高度和具有统计学意义。单侧完全性唇腭裂组与对照组髁突与升支高度和不对称指数具有统计学意义。结论: 单侧完全性唇腭裂患者下颌骨髁突高度、髁突与升支高度和存在不对称畸形,患侧明显小于健侧,且髁突与升支高度和不对称指数与正常牙合人群比较存在差异。     

成人下颌升支应用解剖的研究

目的　研究成人下颌升支后份及髁突的应用解剖。方法　对 16个成人离体下颌升支后缘高度、升支后份厚度 ,下颌孔后缘至下颌升支后缘的距离、髁突高度、髁突颈前后径、内外径测量分析。结果　下颌升支后缘前方 15mm范围内由后向前逐渐增厚 ,部分下颌升支在下颌孔上方 10mm处无松质骨。结论　应用拉力螺钉进行髁突骨折复位固定时应参照以上解剖规律进行。     

单侧后牙反(牙合)患者髁状突及下颌升支对称性的螺旋CT研究

目的：探讨单侧后牙反[牙合]成年患者髁状突及下颌升支的对称性。方法：对22例单侧后牙反[牙合]患者进行螺旋CT扫描、多层面重建和相关参数测量,并进行统计分析。结果：双侧髁突内、外突面积的差异无统点的距离,髁突内倾角及下颌角点的距离有显著差异,但髁突左右径、髁状突最大横截面积、下颌支高度及下颌支冠状位最大计学意义。结论：单侧后牙反[牙合]患者左右侧髁状突及下颌支的位置不对称,但髁突及下颌升支大小无显著差异。     

下颌升支合并髁状突游离精确复位再植治疗髁状突高位粉碎性骨折

目的介绍下颌升支合并髁状突游离精确复位再植治疗髁状突高位粉碎性骨折的方法与手术技巧。方法对10例患者16侧髁状突颈部高位粉碎性骨折行下颌升支髁状突游离并准确原位复位钛板固定,术后定期随访检查下颌运动,牙列咬合,张口度并行X线片及CT检查。结果全部伤口一期愈合,随访1～3年患者张口度牙列咬合均恢复至基本正常,无关节疼痛、弹响及明显功能障碍。结论本方法操作简便、损伤较轻、复位准确、固定可靠,并发症较少且轻微,适用于有明显移位的髁突高位粉碎性骨折,升支高度明显变短,无法通过腮腺切口或仅通过下颌下后方切口复位的患者,但髁状突的形态改变和适应性功能改建仍需长期继续观察。     

SPECT-CT对成人下颌偏斜患者双侧颞下颌关节代谢及形态对称性研究

目的:利用SPECT-CT骨显像对成人下颌偏斜患者双侧颞下颌关节代谢及形态对称性研究。方法:对36例成人下颌偏斜患者行SPECT骨显像,对髁突、下颌升支、下颌角图像进行冠状面、矢状面、横断面采集进行三维重建,计算出放射性计数比值,并通过CT扫描三维重建后同机融合,根据双侧颞下颌关节解剖关系测量偏斜侧及对侧髁突的高度、内外径、后斜面倾斜角及后斜面长度的差异,进行对比观察。结果:颞下颌关节各区域(髁突、下颌升支、下颌角)放射性计数比值均有所不同,偏斜侧的放射性计数比值均低于对侧,且两侧放射性计数比值有显著差异(P＜0.05);偏斜侧髁突高度及内外径均较之对侧减小(P＜0.01);偏斜侧髁突后斜面长度、后斜面倾斜角较之对侧增大(P＜0.01)。结论:SPECT-CT骨显像对成人下颌偏斜疾病的诊断评估起到了至关重要的作用。     

渐进性髁突吸收致下颌后缩正颌外科的治疗进展

病因及发病机制仍不明确的渐进性/特异性髁突吸收(PCR/ICR),是一种发生在髁突的罕见的骨吸收性疾病,临床表现为髁突形态改变、体积减小和下颌升支高度降低等,后期往往出现比较严重的下颌后缩畸形及咬合功能障碍.手术作为一种治疗牙颌面畸形的有效方案,可以达到功能性及面型美观的改善.本文就PCR致下颌后缩的正颌外科治疗作一综述.     

颌下切口下颌升支垂直截骨在髁突高位骨折手术中的应用

目的:探讨应用颌下切口下颌升支垂直截骨术治疗髁突高位骨折的效果。方法:对16例(19侧)下颌骨髁突高位骨折患者采用颌下切口下颌骨升支后缘垂直截骨取出升支后缘骨块将骨折的髁突游离后取出,体外直视下将骨折片与升支后缘骨块复位固定后再回植,行颞下颌关节重建。结果:于术后6、12、24个月复查全部患者的开口度为30～48 mm,平均34.92 mm。所有患者咬合关系良好,无关节疼痛症状。部分病人有轻度开口偏斜,均<3 mm,有1例患者有关节弹响。结论:颌下切口下颌升支垂直截骨是治疗髁突高位骨折的一种可选择方法,具有操作简便、复位准确、近期疗效满意等优点。     

安氏II类骨性下颌后缩患者Twin－Block矫治前后下颌骨变化的三维测量研究鄢

目的：观察安氏Ⅱ类下颌后缩病例Twin－Block矫治器治疗前后下颌骨的三维变化,探讨Twin－Block对下颌骨生长发育的影响。方法：替牙晚期、恒牙列早期安氏Ⅱ类骨性下颌后缩病例10例,采用Twin－Block矫治器矫治,矫治前、后拍摄CBCT,应用Mimics 17．0软件进行下颌骨三维重建后定点测量,SPSS 13．0软件进行统计分析。结果：矫治后下颌骨综合长度、下颌体、下颌升支长度增长明显,有统计学差异,但是髁突宽度及喙突长度无明显变化。结论：Twin－Block功能矫治可以促进安氏Ⅱ类骨性下颌后缩患者下颌骨长度及升支高度的增长。     

青少年下颌后缩患者颅颌面硬组织结构特征的Delaire头影测量初步分析

目的采用Delaire头影测量法分析重庆地区青少年下颌后缩患者颅颌面硬组织特征及其补偿机制,为进一步诊断、治疗设计及预后分析提供参考。方法选取重庆地区11～14岁下颌后缩患者56例及正常青少年40例为研究对象,拍摄头颅侧位片,采用传统头影测量法和Delaire头影测量法分析其颅颌面硬组织结构特征。结果传统头影测量法分析发现,与正常相比,下颌后缩患者∠SNB、Co-Go、Co-Pog、U1-L1减小,∠ANB、∠SN-MP、L1-MP增大,∠SNA、Go-Pog无统计学差异。Delaire头影测量法分析发现,下颌后缩患者∠1、∠5、（Cp-Oi）/C2减小,∠2、（M-Cp）/C2、∠3、∠4增大,C3/C2、NP-F1无统计学差异;Me-F1为-8.70 mm±2.48 mm,Me-Met为5.74 mm±2.58 mm。结论Delaire头影测量法可较直观地定量评估下颌后缩患者颅颌面骨骼结构特征及其补偿机制,下颌后缩畸形主要由下颌骨相对后移及下颌骨发育不足所致。     

替牙期骨性Ⅲ类不同垂直骨面型患者的髁突形态特点

目的 比较替牙期骨性Ⅲ类不同垂直骨面型患者的髁突形态特点及差异,为替牙期颅面部生长发育的研究和临床诊疗提供一定的参考依据。方法 选择替牙期骨性Ⅲ类错患者共60例为研究对象,按照不同的垂直骨面型分为高角组、均角组和低角组,每组20例。采用计算机辅助X线头影测量技术,对3组患者的全颌曲面断层片进行测量,比较各组间髁突形态特点。结果 替牙期3组患者的髁突上部高度h值有统计学差异（P＜0.01）,高角组最小,低角组最大（P＜0.05）;升支高度RH值组间无统计学差异（P＞0.05）;h/RH值组间有统计学差异（P＜0.01）,高角组低于均角组和低角组（P＜0.05）;髁突高度与髁突颈部宽度的比值在组间亦无统计学差异（P＞0.05）。结论 替牙期骨性Ⅲ类不同垂直骨面型患者的髁突形态存在差异,这可能与不同垂直骨面型的生长趋势有关。     

Changes in the position of the condyle after bilateral sagittal split ramus osteotomy in patients with mandibular retrusion and protrusion: a new condyle: fossa matching concept

The purpose of this study was to compare the condylar positional changes after bilateral sagittal split ramus osteotomy (BSSRO) in patients with mandibular retrusion and those with mandibular prognathism. We also studied the correlation between the degree of matching of the condyle and fossa, and condylar displacement. Thirty patients with mandibular retrusion (n = 11) or mandibular prognathism (n = 19) who underwent BSSRO were included. The condylar position was assessed from spiral computed tomographic (CT) scans taken preoperatively, during the first postoperative week, and at least 6 months postoperatively. All data were measured by MIMICS 17.0 and analyzed by Student’s t test and Pearson’s correlation analysis. The size of the condyles of patients with mandibular retrusion was significantly less than those of patients with mandibular prognathism (491.5 (172.8) compared with 823.2 (212.0) mm³). The size of the glenoid fossa in those with mandibular retrusion (599.6 (110.4) mm³) and those with prognathism (597.6 (151.6) mm³) did not seem to differ. Postoperatively the condyles moved outwards, backwards, and downwards in both groups of patients. Correlation analysis between the condyle:fossa volume ratio and the condylar positional changes showed that a large condyle:fossa volume ratio correlated with the smaller positional changes in the condyle. The condylar position changed immediately after mandibular advancement and setback, and persisted in the long term. Larger condyles tended to have fewer positional changes.     

Facial development disorders due to inhibition to endochondral ossification of mandibular condyle process caused by malnutrition

Objective:To analyze the effect of protein restriction on histomorphometric parameters of bone remodeling in mandibular condyle process and its possible influence in facial development in growing rats.Materials and Methods:Wistar rats weaned at the age of 21 days were assigned to one of the following groups: control (fed a regular hard diet ad libitum) and protein restricted (PR) (fed a hard diet lacking in protein ad libitum). The animals were euthanized on day 35 after the onset of the experiment. Mandibles were resected, fixed in 10% formalin, hemisected at the symphysis, and then radiographed in order to perform cephalometric studies of the condylar process length and the height of the lower alveolar process. Mandibles were then processed for light microscopy, and histomorphometric determinations were performed on histologic sections of the condylar process subchondral bone.Results:The PR group showed a significantly lower body weight than control group at the end of the experiment. The length of the condylar process was lower in the PR group; however, the diet used in this study did not affect the height of the lower alveolar process. The histomorphometric analysis showed that the PR group exhibited a statistically significant decrease in bone formation and bone volume in condylar process subchondral bone.Conclusion:Protein restriction inhibits bone formation and longitudinal growth in the mandibular condylar process. This result suggest that protein restriction can alter normal facial development.     

A Study of Mandibular Shape

Abstract

The technique of medial axis transformation of the outline form was used for the specific analysis of mandibular shape. When used to compare mandibular shape derived from lateral cephalographs between three equal samples of 30 female patients aged 12–15 years, marked overall similarity was noted between patients with Classes I, II and III occlusions. There were however subtle contrasts including the degree of coronoid and condylar separation and orientation of the ramus relative to the corpus. Such constancy of mandibular form derived from this technique of investigation was in marked contrast to the data of traditional cephalometric studies which combine both size and shape parameters together. This study therefore demonstrated that shape appears less variable than size.     

Mandibular antegonial and ramus notch depths and condylar bone change

The present study sought to clarify the relationship between antegonial and ramus notch depths and condylar bone change, and analyse the effects of such change on craniofacial structure. The study sample was of 28 pre-orthodontic patients with signs and symptoms of temporomandibular joint (TMJ) disorders, who underwent helical computed tomography to diagnose their TMJ pathology. Craniofacial structures were compared between 14 subjects with bilateral condylar bone change (BBC group: two male and 12 female) and 14 subjects with no bone change (NBC group: two male and 12 female). Sella-nasion-point B (SNB) and point A-nasion-point B (ANB) angles were significantly smaller in BBC than in NBC, with ramus height and mandibular body lengths significantly shorter in BBC than in NBC. The BBC lower facial height and SN-Go-Ar angle, as well as antegonial and ramus notch depths, were significantly greater than in NBC, and the mandible was significantly more retruded in BBC than in NBC. These results showed that condylar bone change might be related not only to mandibular size (e.g. retrusion) but also to mandibular outline (including antegonial and ramus notch depth).     

Mandibular advancement using a retrocondylar cartilage graft: a 20-year prospective study

We examined the outcome after a mean of 46 months (range 18-204) of 73 patients with severe mandibular retrusion who had surgical advancement of the mandible by a post-condylar cartilage graft. The extent of the mandibular advance and the change in position of the condyle were measured by a previously described cephalometric method. Tomograms of the temporomandibular joint (TMJ) were taken at defined intervals and any changes in the articulation recorded. The mandible was advanced by a mean (S.D.) of 9.8 (3.4) mm. The mean postoperative change recorded on the final cephalometric radiograph was 0.4 (4.7) mm forward (95% CI -0.70 to+1.50). The mandibular condyle was advanced horizontally by a mean 7.2 (2.1) mm and depressed vertically by a mean of 5.9 (2.6) mm. postoperatively the condyle relapsed horizontally by a mean of 1.5mm and moved vertically downward by a mean of 0.2mm. Eleven patients had substantial skeletal relapse. Eight patients were regarded as clinical failures. Skeletal relapse did not always lead to clinical failure because of compensatory mandibular growth. Changes in the condylar region, which contributed to relapse, included condylar absorption and remodelling (n=7) and absorption of the cartilage graft (n=6). There were no postoperative functional problems with the TMJ. We conclude that the post-condylar cartilage graft is a useful technique for the treatment of certain cases of mandibular retrusion. The postoperative morbidity was less than that reported after other techniques of mandibular advancement including distraction. Skeletal relapse was found in more cases than clinical results had suggested.     

Relationship between bilateral condylar bone change and mandibular morphology: a study using morphometry

This study was undertaken to evaluate the relationship between bilateral condylar bone change (BCBC) and mandibular morphology. Thirty Japanese women with BCBC as diagnosed from computed tomographic scans were compared to 2 control groups: 26 Class I and 25 Class II Japanese women. All cephalograms were traced and scanned, and 14 homologous landmarks were digitized. Coordinates were used for cephalometric analysis, Procrustes analysis, Euclidean distance matrix analysis (EDMA), and thin-plate spline (TPS) analysis. Comparison of the cephalometric data for the BCBC and Class I groups revealed significant shrinkage in the condylar process and ramus height, in addition to a shorter body length. The centroid size showed that BCBC mean geometric forms were smaller than those of Class I and Class II. The landmark morphology of the BCBC group differed from both Class I and Class II, as shown by the residuals (P < .001). EDMA showed expansion of infradentale-pogonion (9.9%) and along the anterior slope height of the condyle (28.6%), while the posterior slope height decreased (21.6%). The vertical ramus height (gonioncondylion) also decreased by 11.8% in comparison to Class I. Compared to Class II, BCBC ramus height was shorter by 8.9%, condylar width decreased 13.7%, and the posterior condylar slope was 22% shorter. TPS analysis showed increased antegonial notching, a vertically expanded symphysis, and a collapsed and more horizontal condyle in the BCBC group. The combination of the above methods was very helpful in assessing mandibular morphology and showed that BCBC might be related not only to changes in the condyle, but may dictate changes in the rest of the mandible as well.     

正畸辅助儿童髁突囊内骨折外脱位伴下颌后缩的闭合性治疗

目的 ：尝试正畸辅助闭合性治疗儿童髁突囊内骨折外脱位伴颏部骨折及下颌后缩,并观察其短期治疗效果。方法 ：1例9岁儿童外伤后15 d就诊,临床及影像学检查诊断为颏部骨折,双侧髁突囊内骨折外脱位,伴下牙弓增宽、下颌后缩。取模设计模型外科,制作Herbst矫治器。全麻下手法复位双侧髁突并缩窄下牙弓,同时戴入矫治器前移下颌。结果 ：配戴1个月后去除矫治器,随访6个月后患者咬合关系正常,下颌运动无碍,锥形束CT（CBCT）显示双侧髁突愈合改建良好,颏部骨折对位愈合。结论 ：借助Herbst矫治器的辅助,可闭合性治疗儿童髁突骨折外脱位伴颏部骨折及下颌后缩,短期随访获得了良好的咬合关系、髁突形态及下颌功能。     

Growth of the mandible following replacement of the mandibular condyle with the sternal end of the clavicle: an experimental investigation in Macaca mulatta.

This study was designed to investigate the long-term effects of transplanted clavicles to the temporomandibular joint (TMJ) in juvenile monkeys. Sixteen juvenile female monkeys (Macaca mulatta) were used in this experiment. Eight animals were used as controls and were allowed to grow undisturbed for an 18-month period (group control). Eight animals were divided into two groups and underwent bilateral condylar excision via extraoral vertical ramus osteotomies. Four of these animals had their condylar segments removed and immediately replaced to serve as surgical controls (group condyle). The other four underwent condylar replacement with the sternal end of their clavicles (group SCJ). Standardized lateral cephalometric radiographs with the aid of tantalum bone markers were used to evaluate maxillary and mandibular growth. One-way analysis of variance (ANOVA) was used to determine the significance of differences between groups. All animals showed good mandibular function and a class I molar relationship following an 18-month evaluation period. Statistical analysis showed there was no significant difference in maxillary or mandibular growth between any of the three groups. The results of this investigation show that the sternal end of the clavicle may be a viable option in mandibular condylar transplant surgery.