骨性Ⅲ类错牙合患者后退接触位的头影测量分析

目的:评价骨性Ⅲ类错牙合患者牙尖交错位与后退接触位的头影测量数据差异。方法:选择16例伴下颌有功能性移位的骨性Ⅲ类患者,(RCP位ANB<0°),测量分析治疗前ICP位与RCP位的头颅侧位片。使用SPSS17.0统计软件对数据进行统计分析。结果:在ICP位与RCP位,骨性指标SNB角、颌突角、FMA角、MP-SN角、Y轴角及N-per to Pog距离、ANB角、Wits值、APDI值、反覆盖、ODI值均有显著性统计学差异(P<0.001)。牙性指标U1-L1角(P<0.01),FMIA角(P<0.001)有统计学差异。软组织指标颏前点至零子午线距离(P<0.001),Z角(P<0.01)也有统计学差异。结论:对于存在功能性移位的骨性Ⅲ类患者,术前RCP位头颅侧位片分析对诊断错牙合严重程度和制定治疗方案有重要意义。     

Dynamic MRI evaluation of tongue posture and deglutitive movements in a surgically corrected open bite

Tongue thrust usually develops in the presence of anterior open bite in order to achieve anterior valve function. In the literature, tongue thrust is described both as the result and the cause of open bite. If it is an adaptation to malocclusion, then tongue posture and deglutitive tongue movements should change after treatment. In this case report, an adult who had skeletal open bite and Class II malocclusion caused by mandibular retrusion was treated surgically. The mandible was advanced in a forward and upward direction with a sagittal split osteotomy. The open bite and Class II malocclusion were corrected and an increase in the posterior airway space (PAS) was observed. Pretreatment and posttreatment dynamic magnetic resonance imaging (MRI) revealed that tongue tip was retruded behind the incisors and contact of the tongue with the palate increased. It was also determined that the anterior and middle portions descended, whereas the posterior portion was elevated at all stages. Advancement of the mandible, correction of open bite, and an increase in PAS affected not only the tongue posture and deglutitive movements, but also the breathing pattern of the patient.     

No posterior mandibular displacement in Angle Class II, division 2 malocclusion as revealed with electromyography and sirognathography.

The activity of the anterior and posterior temporal, and of the masseter muscles was studied by electromyography and the position of the mandible by sirognathography. The recordings were made in 22 children, aged 8-13 years, with Angle Class II, division 2 malocclusion before and during treatment of their malocclusion. The treatment comprised two phases: proclination of the upper incisors and bite raising with a removable plate, and the subsequent correction of the distal occlusion with an activator. The aim of the study was to reveal signs of anterior mandibular positioning during the treatment. The electromyographic recordings were made in the rest position of the mandible, and during maximal biting, chewing, and swallowing. The sirognathographic recordings comprised the positions of the mandible at rest, at intercuspation, and during tooth contact during chewing and maximal mandibular movements. The muscle activity at rest was unchanged during the period of observation. The activity during maximal biting, chewing, and swallowing decreased during the phase of proclination, which was interpreted as a result of occlusal instability. The positions of the mandible at rest, at intercuspation, and during chewing were stable during the treatment. Neither the electromyographic recordings nor the recordings of mandibular positions revealed any signs of anterior mandibular positioning during the treatment of the Class II, division 2 malocclusion.     

Correction of Class?II, Division 2 malocclusions using a completely customized lingual appliance and the Herbst device

Aim

The purpose of the present study was to examine the efficiency of correcting a Class?II, Division?2 malocclusion using a completely customized lingual appliance.

Materials and methods

In 18 consecutively completed, Class?II, Division?2 malocclusion patients, the correction of the upper incisor inclination, deep and distal bite were assessed by means of plaster casts, digital lateral cephalograms, and intraoral photographs taken at the time of debond. Furthermore, two independent calibrated examiners determined the weighted Peer Assessment Rating index (PAR Index) of the initial and end models.

Results

All Class?II, Division?2 patients were treated successfully: upper incisor inclination using the palatal plane as a reference improved on average from 95.4° to 111.2°. The deep bite was reduced on average from 3.6?mm to 1.7?mm. Neutral occlusion was achieved in all patients who had undergone correction of an initially pronounced distal occlusion (4.5?mm on average). An 86.2% marked improvement was observed in the weighted PAR index score from an average of 24.7 at the beginning of treatment to 2.9 at the end of treatment, with no patient classified as ??worse or no different.??

Conclusion

Class?II, Division?2 malocclusions can be efficiently and reliably treated by a combination of a completely customized lingual appliance and the Herbst device.     

Electromyography of masticatory muscles in three jaw registration positions

The purpose of this study was to investigate whether anteroposterior changes in mandibular position affect masticatory muscle activity. The electromyographic (EMG) activity of masticatory muscles during full and partial (10%) clenching in three mandibular bite registration positions--retruded contact position (RCP), intercuspal position (IP), and muscular position (MP)--was studied. Three groups of subjects with different ranges of anteroposterior positioning of the condyles were evaluated (normal occlusion, Class II, Division 2 malocclusion, and dual bite malocclusion). A posterior stabilizing splint for each registration position was made. EMG data were obtained from three bilateral muscles (masseter, anterior temporal, and posterior temporal). Clenching in the RCP elicited the lowest masseter muscle activity during full clenching, and the highest anterior temporal and posterior temporal muscle activity during partial clenching. If the relationships of the masticatory muscles are analyzed through a ratio that represents the interaction between biting and positioning muscles (masseter/posterior temporal muscle ratio), the RCP as compared with other positions had the lowest ratio. The RCP required more positioning muscle activity and permitted less biting muscle activity. There was no significant difference in the muscle activity between the IP and MP registrations. Small changes in jaw position (anterior to RCP) are not critical for the masticatory apparatus provided there is good intercuspation. The results of this investigation suggest that intercuspation in RCP is not the optimal position.     

The effect of anterior inclined plane treatment on the dentoskeletal of Class II division 1 patients

Most of Class II malocclusions are due to underdeveloped mandible with increased overjet and overbite. Lack of incisal contact results in the extrusion of the upper and lower anterior dentoalveolar complex, which helps to lock the mandible and prevent its normal growth and development, and this abnormality is exaggerated by soft tissue imbalance. The purpose of this study was to evaluate the skeletal and dental changes in patients treated with anterior inclined plane appliance in growing patients with moderate Class II Division 1 having deep overbite. In this study, 25 patients, including 15 girls and 10 boys, with a mean age of 9 +/-1.2 years were selected; all of them presented with moderate Class II deep bite with increased overjet and normal or horizontal growth pattern. Pre- and post-treatment X-rays and photos for an average of 8 months were taken. The statistical assessment of the data suggested that there were no significant changes in the vertical skeletal parameters. The mandibular incisors were protruded, whereas the maxillary incisors were retruded. Overbite and overjet were also reduced. There was significant increase in the mandibular length. The results revealed that in mixed dentition patients, the inclined plane corrected Class II discrepancies mostly through dentoskeletal changes.     

Extraction treatment of a Class II division 2 malocclusion with mandibular posterior discrepancy and changes in stomatognathic function

This case report describes the successful extraction treatment of a Class II division 2 malocclusion with mandibular posterior discrepancy and a congenitally missing maxillary lateral incisor on the left side. The posterior space in the mandibular arch was small, and the mandibular second molars were impacted, with distal tipping. The discrepancies in the maxillary and mandibular arches were resolved by extraction of the maxillary lateral incisor on the right side and the mandibular second premolars on both sides. The mesial movement of the mandibular first molars occurred appropriately, with the second molars moving into an upright position. A lip bumper was used with a preadjusted edgewise appliance in the maxillary dentition to reinforce molar anchorage and labial movement of the retroclined incisors. Despite the extraction treatment, a deep bite could be corrected without aggravation as a result of the lip bumper and utility arch in the mandibular dentition. Thus, an Angle Class I molar relationship and an ideal overbite were achieved. The occlusal contact area and masticatory muscle activities during maximum clenching increased after treatment. The maximum closing velocity and the maximum gape during chewing increased, and the chewing pattern changed from the chopping to grinding type. The findings in the present case suggest that the correction of a deep bite might be effective for improving stomatognathic function.     

Orthodontics and vertical distraction osteogenesis of the maxilla

A female patient (age 26) visited the orthodontist for correction of the reduced exposure of the upper incisors during laughing. She also reported crowding of the lower incisors and an association between lisping and her open bite. The diagnosis in this case: a Class III malocclusion case with incisor crowding and an open bite. Because her main complaint was reduced upper incisor exposure while talking and laughing, which would not be corrected with orthodontic appliances only, the position of the maxilla was corrected during orthodontic treatment by means of vertical intra-oral maxillary distraction. An acceptable and relatively stable result was achieved.     

A novel approach for treatment of mandibular deficiency with vertical growth pattern

This case illustrates the treatment of a 10.5-year-old girl with Class II Division I malocclusion and mandibular deficiency combined with vertical growth pattern. The patient was treated by a modified R-Appliance and extraction of upper and lower first bicuspids. Modified R-Appliance was used for 18 months followed by 17 months of Posterior bite plate, after which favorable correction of the malocclusion was observed. The SNB angle increased by 5 degrees and the IMPA decreased by 11 degrees. This case demonstrates that modified R-Appliance can be a suitable method for treatment of mandibular deficient cases with verticalgrowth pattern.     

���˰��Ϣ���2��������Ϸǰ�������9����Ч����

目的研究成人安氏Ⅱ类2分类错患者非拔牙矫治的效果。方法从烟台市口腔医院2005—2007年就诊的正畸患者中选取成人安氏Ⅱ类2分类错患者9例,采用唇倾上前牙、扩大牙弓、上颌平导或斜导的方法,促进下颌前移,并通过Ⅱ类牵引使磨牙关系由Ⅱ类变为Ⅰ类。测量矫治前后X线头影测量和模型测量指标的变化并进行比较。结果头影测量指标:矫治前后上颌骨矢状方向变化差异无统计意义,下颌骨矢状方向由蝶鞍中心、鼻根点及下齿槽座点所构成的角(SNB)平均增加2.3°,垂直方向下颌平面角平均增加了3.1°,上、下切牙唇倾度增加显著。模型测量指标:矫治前后覆明显减小,上、下颌尖牙和上颌磨牙间宽度明显增加,下颌磨牙增加相对较小,但均具有统计学意义。磨牙关系均由Ⅱ类变为Ⅰ类。结论成人安氏Ⅱ类2分类错可以通过唇倾上前牙、扩大牙弓、上颌平导或斜导的方法,促进下颌前移,并通过Ⅱ类牵引使磨牙关系由Ⅱ类变为Ⅰ类。     

Occlusal interferences in orthodontic patients before and after treatment,and in subjects with minor orthodontic treatment need

Different opinions have been expressed concerning the effect of orthodontic treatment on mandibular function. One factor discussed is occlusal interferences. The aim of this study was to establish the prevalence of occlusal interferences in 210 orthodontic patients before (mean age 12 years 8 months) and after (mean age 16 years 10 months) treatment and to compare them with subjects with minor orthodontic treatment need. The results showed a decrease in retruded contact position/intercuspal position (RCP/ICP) interferences in all morphological deviations, age, and gender groups. The prevalence of mediotrusion interferences decreased in some types of malocclusions whilst in others there was no change. One reason for this is that treatment was started when the majority of the patients had no second or third molars erupted. At the final registration, the second molars were erupted in all patients, and the third molars were erupted in approximately 25 per cent. Mediotrusion interferences were more consistent with basal morphological deviations, for example, Class III relationships and anterior open bite were more consistent in the same person, and more difficult to eliminate than RCP/ICP interferences. RCP/ICP interferences, often caused by dental deviation in position, size, and shape, were easier to correct. Optimal orthodontic treatment, if necessary, including selective grinding, will decrease the prevalence of occlusal interferences.     

正畸治疗安氏Ⅲ类错伴下颌偏斜的临床研究

目的探讨治疗安氏Ⅲ类错伴有单侧的后牙反、锁和单侧前牙反的牙源性下颌偏斜的有效方法。方法选择安氏Ⅲ类错伴单侧的后牙反、锁和单侧前牙反等牙源性下颌偏斜患者21例,年龄8~25岁,平均15.5岁。单侧后牙反、锁引起的下颌偏斜通过上颌扩弓、上下牙交互牵引纠正宽度不调,促使下颌自行复位;前牙反通过Ⅲ类牵引予以解除。结果 21例患者均取得良好的矫治效果,治疗后颜面对称性和咬合关系恢复正常,颏点偏斜平均减少（2.9±0.6）mm,因长期错导致的下颌骨偏斜亦得到了明显改善。结论牙源性下颌偏斜,经过合理正畸治疗,随着单侧后牙反、锁及单侧前牙反的解除可得到明显的改善。     

A growth-related concept for skeletal class II treatment.

The use of a combined activator--high-pull headgear appliance for treatment of Class II, Division 1 malocclusion is presented as a preliminary report. The activator itself is equipped with a palatal bar, lower lip pads, and torque-control auxiliaries for the upper incisors. The face-bow is mounted directly on the activator, and the extraoral force vector is equivalent to that of an anterior high-pull vector. During bite registration the veritcal displacement of the mandible is restricted to a minimum, and the anterior displacement should not exceed 6 mm. On the basis of current knowledge of the growth of the bony facial structures, treatment objectives and a specific approach for skeletal Class II correction are defined. Following these objectives, the therapy aims at correcting the malocclusion without diverting the anterior landmarks of the bony face from their specific lines of growth. This is brought about by the corresponding mechanics of the activator-headgear combination. The corrective effect of this appliance may be assumed to be the result of several different factors. The maxillary dentition is restrained in a posterior cranial direction, and an inhibitory effect on the maxilla counter to its line of development is attained. The mandibular dentition is influenced in an anterior downward direction by means of the bite registration, and the occlusion is unlocked during treatment. Any transfer of distally directed headgear forces from the maxilla to the mandible is prevented. Temporary stimulation of condylar growth, possibly combined with temporary posterior deflection of condylar growth, may also be induced. In this way it is possible to take maximum advantage of condylar growth in the sagittal dimension. Thus, not only is the malocclusion corrected but, at the same time, decisive profile improvement is achieved by anterior development of the mandible. From the experience gained so far with a Class II, Division 1 sample undergoing treatment with the activator-headgear combination, it would appear that skeletal control of the direction of facial growth during treatment is possible. A quantitative report on this group of approximately forty patients, some of whom are still receiving treatment, is in preparation.     

Mini-implants for en masse intrusion of maxillary anterior teeth in a severe Class II division 2 malocclusion

This case report describes the treatment of a 16-year-old post pubertal male patient with a severe Class II division 2 malocclusion and 100% deep bite. In the first phase of treatment, a 'Jones-Jig' molar distalization appliance was used to distalize the maxillary molars by more than 6 mm, to achieve a Class I molar relation. In the second phase of treatment, mini-implants were inserted between the roots of the maxillary lateral incisor and canine to intrude all the maxillary anterior teeth en masse in a single step. Four millimetres of intrusion was achieved. The implants remained stable throughout treatment. In the mandibular arch the incisors were proclined to alleviate the severe crowding. Good overjet and overbite was achieved and has been maintained one year after completion of active orthodontic treatment.     

Use of the centroid method of occlusion for studying the vertical and horizontal relationship of the mandible and maxilla

The aim of the present study was to verify whether the centroid method of occlusion for studying mandibular and maxillary growth enables accurate determination of vertical occlusal patterns (open and deep bite). Lateral cephalograms were obtained of Japanese adult females aged over 18 years of age with a Class II malocclusion (61 open bite and 47 deep bite), or a Class III type open bite (70 subjects) or deep bite (21 subjects) malocclusion. One-way analysis of variance followed by a Bonferroni's t-test was used to compare the results among these four groups. The Deltaabc area, which comprised the palatal, Ar-Gn, and A-B planes, was shown to be significantly larger in the open bite than in the deep bite group for both Class II and Class III malocclusion types (P < 0.01). There was no difference in the Deltaabc area between the Class II and Class III open bite groups or between the Class II and Class III deep bite groups. These findings suggest that the centroid method of occlusion is a versatile diagnostic technique that can accurately differentiate between vertical occlusal patterns of Class II and III types of malocclusion limited to Japanese adult females. The analytical method is also unaffected by gnathostatic differences according to Angle classification.     

Mandibular function in children with a lateral forced bite

Open-close-clench cycles have been studied in 12 children with a lateral forced bite in order to investigate how the neuromuscular system of the mandible adapts itself in the presence of occlusal interferences. The mandibular movements were registered in a frontal plane at the central incisors with an opto-electronic registration technique. Series of 35 cycles were recorded to intercuspal position, against flat occlusal splints constructed in intercuspal raised and retruded positions, and against splints with occlusal stops in a retruded position. Average lateral displacements of the mandible during cycle series against flat occlusal splints were measured relative to cycle series to intercuspal position and relative to series against splints with occlusal stops in the retruded position. The lateral mandibular displacements were registered at maximal tooth-tooth or tooth-splint contact and at 7, 14, and 21 mm mouth-opening. It was found that the mandible in the subjects investigated is displaced to the forced bite side both during cycle series into intercuspal position as well as when occlusal contacts are eliminated by the use of flat occlusal splints.     

A cephalometric comparison between Angle Class II, division 2 malocclusion and normal occlusion in adults

The lateral cephalometric radiographs of 56 adults with Angle Class II/2 malocclusion and of 81 persons with normal Class I occlusion are compared. The statistical analysis includes the calculation of the mean value, standard deviation and the determination of differences (Wilcoxon rank-test). Group characteristics are tested by stepwise discriminant analysis. The following statements regarding Angle Class II/2 as compared with normal Class I result from this study. The upper incisors are in a retruded position. The B-point is significantly retropositioned, whereas the pogonion is in a more normal position. The length of the mandibular corpus and the total length of the mandible are slightly diminished only. Normal values result for the size and position of the maxilla, the inclination of the mandibular corpus (angle between mandibular plane and NSe) and the gonion angle.     

Long-term stability of conservative orthodontic treatment in a patient with rheumatoid arthritis and severe condylar resorption

Rheumatoid arthritis is a chronic inflammatory condition that can result in progressive destruction of the articular surfaces of the joints, including the temporomandibular joint. The purpose of this article is to report the conservative correction of a Class II malocclusion in a woman with rheumatoid arthritis. The patient was 32 years 6 months old at the start of treatment. She had a convex profile and a skeletal Class II jaw-base relationship caused by severe condylar resorption. An anterior open bite of -2.0 mm and an excessive overjet of 10.0 mm were observed. Severe crowding was shown in the mandibular incisors. After 8 months of splint therapy, all first premolars were extracted, and 0.018-in preadjusted edgewise appliances were placed in both arches. Class II elastics were used during space closure. After 41 months of active orthodontic treatment, an acceptable occlusion was achieved, and the facial profile was considerably improved. From the cephalometric evaluations, the mandible was rotated counterclockwise, and the mandibular plane angle was significantly decreased. However, the anteroposterior position of the chin was not changed. The condylar resorption was not changed during and after orthodontic treatment. Conclusively, the proper facial profile was maintained, and the occlusion was stable after a 5-year retention period. Our results suggest the possibility of compromised treatment in a Class II malocclusion with an anterior open bite because of rheumatoid arthritis.     

口外颈牵引装置早期矫治安氏Ⅱ类1分类错的疗效研究

目的 评价口外颈牵引装置对生长发育期的安氏Ⅱ类1分类错(牙合)患者的疗效。方法 采用侧位X线头影测量,对15例患者进行观察分析。结果 上颌骨向前生长受到抑制,下颌骨生长得到充分表达,上下颌骨矢状不调得以改善。上颌第一恒磨牙伸长并向远中移动,上颌切牙唇倾角度减小,第一恒磨牙关系恢复至中性(牙合),覆(牙合)、覆盖有不同程度的减小。同时发现,腭平面角、(牙合)平面角、下颌平面角均无显著性变化。结论 口外颈牵引装置对生长发育期安氏Ⅱ类1分类错(牙合)有明显的矫形效果。     

高位头帽式肌激动器临床疗效的定量分析

目的：探讨高位头帽式肌激动器（HGAC）矫正骨性安氏Ⅱ类错He的作用机理和疗效。方法：采用HGAC对17例骨性安氏Ⅱ类错He患者进行矫治，应用Pancherz分析法结合一些常用测量项目对治疗前后X线头影片进行对比分析。结果：HGAC对上颌骨的生长发育有抑制作用，尤其体现在垂直方向上；对促进下颌骨的前后向生长，改善下颌后缩有明显作用，同时还避免了下颌顺时旋转的负面作用；牙齿牙槽方面对上前牙有舌倾和压入效果，对下前牙的位置控制良好。结论：HGAC对骨性安氏Ⅱ类错He矫治的疗效确切，尤其适用于上牙槽发育过度以及高角型病例。