早期上颌扩弓纠正单侧后牙反(牙合)改善功能性下颌偏斜

目的:通过头颅定位后前位片(P-A)测量,探讨上颌扩弓纠正单侧后牙反(牙合),改善早期功能性下颌偏斜的临床效果.方法:混合牙列或早期恒牙列,上颌单侧后牙反(牙合)伴有/或不伴有前牙反(牙合),下颌功能性偏斜病例16例,采用上颌Quad-Helix扩弓方法,矫治前后头颅定位后前位片(P-A)测量分析,用统计软件处理数据.结果:单侧后牙反(牙合)矫正后,面部不对称有明显改善.结论:混合牙列或早期恒牙列,由于单侧后牙反(牙合)导致的功能性下颌偏斜,采用扩大上颌牙弓方法,可使下颌骨的不对称得到明显改善,是早期纠正下颌功能性偏斜的有效方法.     

早期上颌扩弓纠正单侧后牙反改善功能性下颌偏斜

目的:通过头颅定位后前位片(P-A)测量,探讨上颌扩弓纠正单侧后牙反牙合,改善早期功能性下颌偏斜的临床效果。方法:混合牙列或早期恒牙列,上颌单侧后牙反牙合伴有/或不伴有前牙反牙合,下颌功能性偏斜病例16例,采用上颌Quad-Helix扩弓方法,矫治前后头颅定位后前位片(P-A)测量分析,用统计软件处理数据。结果:单侧后牙反牙合矫正后,面部不对称有明显改善。结论:混合牙列或早期恒牙列,由于单侧后牙反牙合导致的功能性下颌偏斜,采用扩大上颌牙弓方法,可使下颌骨的不对称得到明显改善,是早期纠正下颌功能性偏斜的有效方法。     

儿童单侧后牙反患者下颌及颞颌关节的对称性研究

目的研究儿童单侧后牙反牙合患者下颌及颞颌关节的对称性。方法以26例替牙期单侧后牙反牙合患儿为试验组,28名正常牙合替牙期儿童为对照组,分别摄定位颏顶位片及双侧颞颌关节中位断层片进行比较。结果替牙期单侧后牙反牙合患儿在下颌骨坐标系中DMP点更靠颊侧。在颅底坐标系中,反牙合侧DMP点更靠远中,DMP、MM、DM点更靠颊侧。双侧髁突位置不对称、非反牙合侧关节前间隙减小,上后间隙均增大。结论相对于下颌坐标系,反牙合侧第一磨牙位置与对侧相比更靠远中及颊侧。在骨性结构上,未见下颌的不对称。试验组双侧髁突位置及关节间隙有差异,说明下颌发生功能性侧方移动。     

单侧后牙反(牙合)髁突前伸运动轨迹的研究

目的:探讨单侧后牙反牙合髁突前伸运动轨迹的特征并比较与正常牙合之间的差异。方法:正常牙合5人,单侧后牙反牙合7人,采用计算机化的髁突运动轨迹Ⅰ型描记仪及分析软件,记录下颌最大前伸运动时髁突在水平面及矢状面上的运动轨迹。结果:单侧后牙反牙合者前伸后退运动轨迹多不重合,反牙合侧前伸髁道斜度明显大于对侧。结论:单侧后牙反牙合者存在前伸牙合干扰,其两侧颞下颌关节不对称。     

儿童功能性单侧后牙反患者的髁突对称性及矫治后髁突位置变化的研究

目的探讨儿童功能性单侧后牙反患者的髁突对称性及上颌扩弓治疗后髁突位置的变化。方法选择22例通过上颌扩弓成功矫治的功能性单侧后牙反儿童患者,男10例,女12例,年龄6.0-8.5岁,平均7.5岁作为实验组。另选择22例正常患者,男11例,女11例,年龄6.5-9.0岁,平均7.5岁作为对照组。反组矫治前后与对照组患者均拍摄曲面断层片和双侧闭口位矫正薛氏位片,测量髁突形态的不对称指数和髁突在关节窝中的相对位置。用SPSS 12.0软件进行统计分析。结果反组患者两侧髁突形态无明显不对称,与对照组相比,髁突高度(CH)、升支高度(RH)以及两者之和(CH+RH)的不对称指数均无统计学差异。反组矫治前(T1)两侧髁突在关节窝中的位置有明显差异,非反侧关节前间隙减小(P<0.05),上后间隙增大(P<0.05)。非反侧髁突在关节窝中的位置(R)相对反侧更加靠前(P<0.01)。矫治后(T2)双侧髁突位置变得相对对称。结论儿童功能性单侧后牙反患者的髁突形态相对对称,而髁突位置存在不对称性,说明下颌向反侧发生功能性偏斜,而这种偏斜并未导致髁突发生骨性不对称;正畸治疗可使两侧髁突位置更加协调。     

成人下颌偏斜患者颞下颌关节形态及位置的变化

目的：研究下颌偏斜患者颞下颌关节形态及其位置的变化.方法：对21例下颌偏斜患者和20例个别理想[牙合]志愿者拍摄颞下颌关节中位断层片,选择描述髁突位置及髁突和关节窝形态的15个指标进行测量及统计分析.结果：下颌偏斜患者双侧关节结节高度、关节窝指数增大,髁突后斜面与水平基准线的夹角减小;偏斜侧的关节前间隙、关节前后间隙面积比,髁突高度、髁突上部高度减小;对侧的关节上间隙、髁突高度、髁突上部高度、髁突前斜面与水平基准线的夹角、关节窝后斜面与水平基准线的夹角增大.结论：下颌偏斜患者的双侧髁突和关节窝形态及髁突在关节窝中的位置都发生了改变,尤其以非偏斜侧髁突变化较为明显.     

成人下颌偏斜患者颞下颌关节形态变化与TMD的关系

目的:研究下颌偏斜患者颞下颌关节形态、位置的变化与颞下颌关节紊乱病的关系.方法:拍摄21例下颌偏斜患者和20例个别正常(牙合)志愿者的颞下颌关节中位断层片,选择描述髁突位置及髁突和关节窝形态的17个指标进行测量及统计分析,将有变化的指标与Fricton颞下颌关节紊乱指数(CMI)进行相关性分析.结果:成人下颌偏斜患者偏斜侧关节前间隙(A)、关节前后间隙面积比(X/Y)及对侧关节上间隙(S)、髁突高度(TCH)的变化与Fricton颞下颌关节紊乱指数(CMI)有相关性.结论:成人下颌偏斜患者偏斜侧髁突在关节窝中的位置后移,对侧髁突在关节窝中的位置向前下移位,对侧髁突高度增高与其出现的关节症状有一定相关性.     

单侧后牙反(牙合)时下颌骨的功能性移位及颞下颌关节适应性改变的实验性研究

本实验是研究用活动扩弓导板治疗单侧后牙反(牙合)时,下颌骨功能性移位的改善及髁突变化情况。研究对象是6名7～11岁儿童,单侧后牙反(牙合)且下颌中线向反(牙合)侧偏移2mm以上,ICP位髁突位置正常。 研究方法 Ⅰ阶段,用覆盖(牙合)面的平面扩弓导板消除因双侧咬合不平衡引起的不对称神经肌反射(该     

单侧后牙扩弓的有效方法

目的:探讨附颊屏的(牙合)垫矫治器进行单侧后牙扩弓,治疗单侧后牙反(牙合)的可行性.方法:选择混合牙列期或恒牙列早期的单侧后牙反(牙合)病例4例,男2例,女2例,年龄12～15岁,平均13.5岁,应用附颊屏的(牙合)垫矫治器配合改良横腭杆进行治疗,对矫治前后模型进行测量分析.结果:4例患者经过3～5个月的治疗,单侧后牙反(牙合)均纠正,效果满意.模型分析显示,反(牙合)侧治疗前后第一、第二前磨牙腭尖及第一磨牙近中腭尖到腭中缝的距离变化均较正常侧明显.结论:附颊屏的(牙合)垫矫治器配合改良横腭杆治疗单侧后牙反(牙合),既可保持正常侧良好的咬合关系,又可快速矫治后牙反(牙合).     

成人下颌偏斜患者颞下颌关节对称性研究

目的:了解下颌偏斜患者颞下颌关节形态学差异及相关性。方法:对21例下颌偏斜患者拍摄颞下颌关节中位断层片,选择描述髁突位置及髁突和关节窝形态的15个指标进行测量及统计分析。结果:下颌偏斜患者非偏斜侧的髁突在关节窝中的位置较偏斜侧向前下移位;非偏斜侧的髁突高度、髁突上部高度较偏斜侧高;非偏斜侧的髁突前斜面斜度、关节窝后斜面的斜度较偏斜侧大。双侧髁突前斜面斜度与关节前间隙、关节窝深度呈正相关;髁突上部高度与髁突高度呈正相关;偏斜侧髁突后斜面斜度与关节窝后斜面斜度呈正相关;非偏斜侧髁突后斜面斜度与关节上间隙、关节结节高度呈负相关。结论:下颌偏斜患者双侧颞下颌关节具有形态学差异。双侧髁突形态的变化与其同侧关节窝形态的变化及其在关节窝中的位置具有一定相关性。     

Mandibular asymmetry and condylar position in children with unilateral posterior crossbite.

The purpose of this retrospective study was to determine if condylar position in children with functional unilateral crossbites was different from that found in children with Class I noncrossbite malocclusions and if there was a change in condylar position after correction of the crossbite by palatal expansion. Mandibular asymmetry in children with functional unilateral posterior crossbite was also compared to that of a Class I noncrossbite group. Thirty-one children aged 6 to 14 years (mean, 9.3 years; standard deviation, 2.2) with functional unilateral crossbites were compared to 31 children aged 9.5 to 14.1 years (mean, 11.9 years; standard deviation, 1.3) exhibiting Angle Class I noncrossbite malocclusions. Pretreatment submentovertex radiographs were used to study mandibular skeletal, dental, and positional asymmetries with reference to cranial floor and mandibular coordinate systems. In addition, the anterior, superior, and posterior joint spaces were measured to determine differences between the groups with the use of pretreatment and posttreatment horizontally corrected tomograms of the temporomandibular joints. Finally, the distances of the mesiobuccal cusp of the upper first molar relative to the buccal groove of the lower first molar were measured in both groups before treatment. Univariate analyses revealed that the mandibles of children in the functional unilateral posterior crossbite group exhibited asymmetry in both anteroposterior and transverse dimensions when compared with the Class I noncrossbite group (P <. 05). These asymmetries were the result of a functional deviation of the mandible that was present in all subjects in the crossbite group. This deviation was manifested occlusally by a Class II subdivision on the crossbite side as indicated from the study model analysis (P <.05). Examination of condylar position as evidenced by horizontally corrected tomograms demonstrated a large standard deviation, resulting in an inability to detect any significant differences within or between groups at both T1 and T2 (P >.05). This study raised the question of the appropriateness of measuring joint spaces for routine diagnostic purposes.     

Morphological and positional asymmetries of young children with functional unilateral posterior crossbite.

This prospective clinical study evaluated the morphological and positional mandibular asymmetry of young patients with functional unilateral posterior crossbite. The sample included 9 girls and 6 boys (8.8 +/- 1.0 years of age), evaluated at the initiation of treatment and approximately 6 months after the retention phase (1.1 +/- 0.2 years after initiation of treatment). Each patient had a complete unilateral posterior crossbite involving 3 or more posterior teeth, a functional shift from centric relation-intercuspal position, and no signs or symptoms of temporomandibular disorder. A bonded palatal expansion appliance was used to rapidly expand the maxilla (1 month) and retain the treatment changes (6 months). Zonograms were used to assess articular joint spaces, and submental vertex radiographs were used to assess morphological and positional asymmetry. The results showed that the mandible was significantly longer on the noncrossbite side than it was on the crossbite side. The asymmetry was most evident for the ramus and involved both the condylar and the coronoid processes. The posterior and superior joint spaces were larger on the noncrossbite side than they were on the crossbite side. After treatment and retention, the mandible showed no significant morphological asymmetries. Mandibular growth was greater on the crossbite side than it was on the noncrossbite side, and the mandible had been repositioned; the crossbite side had rotated forward and medially toward the noncrossbite side. We concluded that unilateral posterior crossbites produce morphological and positional asymmetries of the mandible in young children, and that these asymmetries can be largely eliminated with early expansion therapy.     

CBCT evaluation of condylar changes in children with unilateral posterior crossbites and a functional shift

Posterior crossbite is one of the most frequently occurring malocclusions in adolescents with a prevalence of 7% to 23%. The most common form of posterior crossbite is a unilateral posterior crossbite with a functional side shift. It has been suggested that functional posterior crossbites (FUPXB) may result in right-to-left-side differences in the condyle fossa relationship, resulting in temporomandibular joint (TMJ) problems. The objective of this study was to determine if pathological position of the condyles can cause condylar signs or symptoms like degenerative joint disease (DJD) or juvenile condylar resorption (JCR), or if the position of the condyle is just an altered position within the TMJ. Sixty patients with an average age of 9.6years were randomly selected from the office of one of the investigators (T.S.). The study group consisted of 29 patients with a FUPXB and the control group had 31 patients with no posterior crossbite. All patients had multislice CT scans of the TMJ taken as part of the orthodontic records. Transverse widths were measured at the skeletal base and the dentoalveolar base. Molar inclinations, condylar angulations, condylar anterior joint space, superior joint space, and posterior joint space were measured. Independent sample t-tests were used to compare different measurements between groups and paired sample t-tests were used to compare differences within the same patient. Reliability of measurements were determined using pairwise correlation. For dentoalveolar measurements of transverse width, the maxillomandibular difference for the study group was -8.2 mm and for the control group was -4.0 mm. No significant differences were found between the molar inclinations, condylar width, angulation, or any joint space measurements between the two groups. A total of 61.3% of the subjects in the control group and 72.4% in the study group had a radiographic sign of joint disease. The lack of condylar positional differences between the control and crossbite groups suggests that TMJ signs and symptoms in the study group may be related to remodeling in the TMJ instead.     

Condyle fossa relationship associated with functional posterior crossbite,before and after rapid maxillary expansion

Objective:To investigate condylar symmetry and condyle fossa relationships in subjects with functional posterior crossbite comparing findings before and after rapid maxillary expansion (RME) treatment through low-dose computed tomography (CT).Materials and Methods:Twenty-six patients (14 girls and 12 boys, mean age 9.6 ± 1.4 years) with functional posterior crossbite (FPXB) diagnosis underwent rapid palatal expansion with a Hyrax appliance. Patients'' temporomandibular joints (TMJ) underwent multislice CT scans before rapid palatal expansion (T0) and after (T1). Joint spaces were compared with those of a control sample of 13 subjects (7 girls and 5 boys, mean age 11 ± 0.6 years).Results:Anterior space (AS), superior space (SS), and posterior space (PS) joint space measurements at T0 between the FPXB side and contralateral side demonstrated no statistically significant differences. After RME treatment (T1), all three joint spaces increased on both the FPXB side and the non-crossbite side. However, differences were statistically significant only for the SS when comparing the two sides at T1. SS increased more than AS and PS in the non-crossbite condyle (0.28 mm) and FPXB condyle (0.37 mm), and PS increased only on the FPXB side (0.34 mm).Conclusions:There were no statistically significant differences in condyle position within the glenoid fossa between the FPXB and non-crossbite side before treatment. Increases in joint spaces were observed after treatment with RME on both sides. These changes were, however, of small amounts.     

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.     

单侧后牙正锁(牙合)患者下颌侧方运动时的髁突轨迹特征

目的:探讨单侧后牙正锁(牙合)患者在下颌侧方运动过程中髁突的运动轨迹特征及其与正常(牙合)者之间的差异.方法:选取单侧后牙正锁(牙合)患者26例为实验组,个别正常(牙合)26例为对照组,应用髁突运动轴图描记仪(computer aided diagnosis axiograph,CADIAX)记录下颌侧方运动时髁突的运动轨迹.实验数据采用SPSS10.0软件包分析,选用成组t检验、配对t检验或秩和检验比较组间差异有无统计学意义.结果:实验组下颌侧方运动过程中髁突轨迹不流畅变异大,两侧运动轨迹不对称.非锁(牙合)侧髁突的矢状位移、垂直位移以及空间最大位移大于锁(牙合)侧和对照组,水平位移小于后者,差异有统计学意义(P<0.05);非锁(牙合)侧髁突的矢状倾斜度大于锁(牙合)侧和对照组,水平倾斜度小于后者,差异有统计学意义(P<0.05).结论:单侧后牙正锁(牙合)患者下颌侧方运动过程中两侧髁突运动轨迹不对称.     

The functional shift of the mandible in unilateral posterior crossbite and the adaptation of the temporomandibular joints: a pilot study.

Changes in the functional shift of the mandibular midline and the condyles were studied during treatment of unilateral posterior crossbite in six children, aged 7-11 years. An expansion plate with covered occlusal surfaces was used as a reflex-releasing stabilizing splint during an initial diagnostic phase (I) in order to determine the structural (i.e. non-guided) position of the mandible. The same plate was used for expansion and retention (phase II), followed by a post-retention phase (III) without the appliance. Before and after each phase, the functional shift was determined kinesiographically and on transcranial radiographs by concurrent recordings with and without the splint. Transverse mandibular position was also recorded on cephalometric radiographs. Prior to phase I, the mandibular midline deviated more than 2 mm and, in occlusion (ICP), the condyles showed normally centred positions in the sagittal plane. With the splint, the condyle on the crossbite side was displaced 2.4 mm (P < 0.05) forwards compared with the ICP, while the position of the condyle on the non-crossbite side was unaltered. After phase III, the deviation of the midline had been eliminated. Sagittal condylar positions in the ICP still did not deviate from the normal, and the splint position was now obtained by symmetrical forward movement of both condyles (1.3 and 1.4 mm). These findings suggest that the TMJs adapted to displacements of the mandible by condylar growth or surface modelling of the fossa. The rest position remained directly caudal to the ICP during treatment. Thus, the splint position, rather than the rest position should be used to determine the therapeutic position of the mandible.