OBJECTIVE: This study aimed to investigate the therapeutic effects and advantages of skeletal class Ⅲ malocclusion treatment by transmission straight wire technique. METHODS: Ninety-seven patients who received treatment for skeletal class Ⅲ malocclusion at the Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 2012 to January 2017 were selected for this retrospective study. All these patients refused surgery. They were divided into two groups in accordance with the type of skeletal malocclusion: mild-to-moderate skeletal malocclusion group (-4°≤ANB <0°) and severe skeletal malocclusion group (-8°≤ANB<-4°). Each of the two groups was divided further into two small groups in accordance with the technique used: T group (transmission straight wire technique) and M group (MBT technique). RESULTS: The crossbite of all 59 patients in the mild-to-moderate skeletal malocclusion group was successfully treated. The molars were classified as classⅠrelationship, and the facial profile improved. Significant differences were found in the values of U1/SN angle, L1/MP angle, and Lip-Diff between the T and M groups before and after the treatment (P<0.05). The extent of incisor root resorption was lighter in the T group than in the M group (P<0.05). In the severe skeletal malocclusion group, the crossbite of all 38 patients was cured or partially cured. Fourteen patients showed severe lower anterior teeth inclination (five in the T group and nine in the M group), and the profiles did not significantly improve. Significant differences were observed in the values of U1-NA value, U1/SN angle, L1-NB value, L1/MP angle, LLP, and Lip-Diff between the T and M groups before and after the treatment (P<0.05). The extent of incisor root resorption was lighter in the T group than in the M group (P<0.05). CONCLUSIONS Relative to the MBT technique, the transmission straight wire technique has great advantages in improving facial profile, reducing the compensatory inclination of the upper and lower anterior teeth, and reducing the risk of root resorption in the treatment of skeletal class Ⅲ malocclusion.
Cephalometry ; Humans ; Malocclusion ; Malocclusion, Angle Class II ; Malocclusion, Angle Class III ; Maxilla ; Retrospective Studies

The purpose of this study was to compare mandibular teeth development of Angle Class I malocclusion group with that of Angle Class III malocclusion group. The studied subjects consisted of 217 Angle Class I malocclusion patients and 235 Angle Class III malocclusion patients. Two study methods were used. One was to evaluate tooth development degree by means of Nolla stage method, the others was to measure tooth length on panoramic radiograph. The following results were obtained, in 7, 8 and 9 years, tooth development of Angle Class III malocclusion group was significantly faster than that of Angle Class I malocclusion group. in 6 year and 10, 11, 12, 13, 14 years, the difference of tooth development degree between Angle Class III malocclusion group was not significant.
Humans ; Malocclusion* ; Malocclusion, Angle Class I* ; Malocclusion, Angle Class III* ; Tooth*

OBJECTIVETo study the association of vertical facial skeletal types and sagittal facial skeletal types with anterior alveolar bone thickness.

METHODSAmong 168 cases with malocclusion in early permanent dentition stage, 93 patients were male and 75 patients were female. All patients (aged 10-14 years) were divided into 9 groups by different facial skeletal types, mandibular anterior alveolar bone thickness in patients' lateral cephalometric films were measured. ANOVA were performed to measurement results with the SPSS 13.0 statistical software.

RESULTSThough sagittal facial skeletal types were the same, there were significant differences between different vertical facial types groups. The order was low-angle group, average-angle group and high-angle group according to the size. A high-angle individual often had a thin anterior alveolar bone while a low-angle individual often had the opposite morphology character. There was no statistical significance between skeletal type I, II and III. But group of skeletal type III also had a thin alveolar bone thickness which had no significant difference with high-angle group. Low-angle group III had no significant difference with average-angle group I and II in alveolar bone thickness.

CONCLUSIONSagittal facial skeletal types have little influence on anterior alveolar morphology, but the vertical facial skeletal types have strong connection with anterior alveolar bone thickness.

Adult ; Cephalometry ; Face ; Female ; Humans ; Male ; Malocclusion ; Malocclusion, Angle Class II ; Malocclusion, Angle Class III ; Mandible

OBJECTIVETo analyze the morphological characters of Angle's Class III malocclusion patients and the relationship between characters and treatment options.

METHODSA total of 472 Class III patients were collected during 1997-2000. The standardized coordinates' values of the patients were obtained by Procrustes superimposition (PS). Cluster analysis was carried out to divide the patients into different subdivisions and the relationship between treatment options and subdivisions was analyzed.

RESULTS472 patients were divided into 14 subdivisions with special characters. The morphological templates were formed by computer. There were certain relationships between characters and treatment options.

CONCLUSIONThe mechanism of malocclusion of different Class III patients are not necessarily same. The typing has significance to choose the treatment method.

Female ; Humans ; Male ; Malocclusion ; Malocclusion, Angle Class III ; Orthodontic Appliances

OBJECTIVETo investigate the effect of different premolar extraction models on postextraction Bolton overall ratio among different classes of malocclusion.

METHODS180 patients with equivalent skeletal and dental classifications were chosen(Group I, II and III, with 60 per group). According to dental casts, the Bolton overall ratios of each group were measured and compared before and after hypothetical premolar extraction (the four premolar extraction models were all first premolars, all second premolars, upper first and lower second premolars, and upper second and lower first premolars). Chi-square Test analysis was taken within each group in order to compare the abnormal rates of postextraction Bolton overall ratios.

RESULTSThe differences of pretreatment Bolton overall ratios among three types of malocclusions were found statistically significant (P=0.000). For Class I and Class II group, the four extraction models made no statistically significant differences in the abnormal rates of postextraction Bolton overall ratio (P>0.05). For Class III group, the four extraction models made statistically different results that was the upper second and lower first premolar extraction model creating lower abnormal rates than the upper first and lower second premolar extraction model (P=0.002).

CONCLUSIONAs far as the postextraction Bolton overall ratios are concerned, Class I and II malocclusions can choose any of four premolar extraction models, while to Class III malocclusions, the upper second and lower first premolar extraction model fits better than the upper first and lower second premolar extraction model.

Bicuspid ; Female ; Humans ; Male ; Malocclusion ; Malocclusion, Angle Class III ; Odontometry

OBJECTIVETo study the characteristics of the arch form of skeletal Class III malocclusion and provide references for diagnosis and treatment plan.

METHODS7 indexes in dental casts of 47 patients with skeletal Class III malocclusion and 50 individuals with normal occlusion were measured respectively. And differences between corresponding upper and lower measurements were calculated. Independent samples t-test was employed for comparing between the two groups by SPSS 17.0.

RESULTSCompared with normal occlusion sample, Class III malocclusion group had smaller anterior segment lengths and larger canine angles (P<0.05). Differences between upper and lower first premolar widths were larger in males with skeletal Class III malocclusion. And differences between upper and lower anterior segment lengths were smaller in males with skeletal Class III malocclusion (P<0.05).

CONCLUSIONArch widths of patients with skeletal Class III malocclusion are basically normal. The lengths of anterior segment are smaller and the anterior arch forms are straighter.

Bicuspid ; Dental Arch ; Dental Occlusion ; Female ; Humans ; Male ; Malocclusion, Angle Class II ; Malocclusion, Angle Class III

OBJECTIVETo figure out the differences of the morphological characteristics of mandibular symphysis between Class II and Class III adult skeletal malocclusions with different abnormal vertical skeletal patterns.

METHODS109 Chinese female adults of skeletal Class II and Class III were chosen and divided into four groups according to vertical and sagittal skeletal pattern: Class II--vertical-growth-pattern group (n=30), Class III--vertical-growth-pattern group (n=25), Class II--horizontal-growth-pattern group (n=29), Class III--horizontal-growth-pattern (n=25). Lateral cephalograms were taken. The symphyseal widths and heights, along with lower incisor positions were evaluated. Observation and statistics analysis were done to clarify the morphological characteristics of the symphyseal region of different skeletal patterns.

RESULTSThere were morphological differences of symphyseal region between Class II and Class III skeletal malocclusions, but not significant in width and total height. With a vertical-growth-pattern, Class II malocclusions had higher alveolus than Class III, but smaller chin prominence and lower basal bone (P < 0.01). With a horizontal-growth-pattern, Class II malocclusions had higher alveolus (P < 0.05) and larger alveolar top width (P < 0.001). With a same sagittal skeletal pattern, vertical-growth-pattern group had thinner but higher symphyseal region and bigger chin prominence (P < 0.001 in Class II while P < 0.05 in Class III). Besides, a vertical-growth-pattern malocclusion was prone to have a cucurbit-morph chin, of which Id width was larger than basal width (P < 0.01).

CONCLUSIONThere are morphological differences in symphyseal region between Class II and Class III skeletal malocclusions with different abnormal vertical skeletal patterns. The influence of abnormal vertical skeletal pattern to symphyseal morphological characteristics is greater than that of abnormal sagittal skeletal pattern. There is a risk of orthodontic movement of low incisors in vertical-growth-pattern skeletal malocclusion.

Adult ; Female ; Humans ; Malocclusion, Angle Class II ; pathology ; Malocclusion, Angle Class III ; pathology ; Mandible ; pathology

OBJECTIVETo investigate the correlation between Angle's class III patients' occlusion plane and anterior overbite by controlling the changes in occlusion plane during orthodontic treatment.

METHODSIn total, 90 Angle's class III adult orthodontic patients were selected as the experimental group, and 30 normal adults were selected as the control group. According to the overbite, the class III patients were divided into three groups, and 14 indicators were measured. ANOVA and multiple comparison analysis were used to analyze the difference between class III patients, and linear analysis was used to analyze the correlation between anterior overbite and anterior-posterior occlusion plane.

RESULTSIn class Ill patients, posterior occlusion plane and anterior overbite size were negatively correlated (r = -0.24, P < 0.05), whereas anterior occlusal plane and anterior overbite size were positive correlated (r = 0.23, P < 0.05).

CONCLUSIONThe shape of the occlusion plane varies in different anterior overbite patients. During orthodontic treatment in different overbite class III patients, the vertical height of the posterior teeth and the rotation of the occlusion plane should be controlled.

Adult ; Dental Occlusion ; Humans ; Malocclusion, Angle Class III ; Overbite ; Tooth

OBJECTIVEThis study aims to compare the changes of hyoid bone position before and after treatment of Angle class Ⅲ malocclusion using improved appliance FR Ⅲ.

METHODSForty patients with Angle class Ⅲ malocclusion were chosen and divided into two groups, namely, experimental and control. Each group had 20 patients. The young patients in the experi-mental group were treated using improved appliance FR Ⅲ, whereas those in the control group were treated using classic appliance FR Ⅲ. The hyoid bone position of the two groups were comparatively analyzed using an X-ray film before and after treatment.

RESULTSCompared with the condition before treatment, the condition after treatment showed that the hyoid bone position of young patients with Angle class Ⅲ malocclusion treated using improved appliance FR Ⅲ, H-FH, H-S, H-Ptm, and Ar-H-Me exhibited an increased angle (P<0.01), whereas the hyoid bone position of those treated using H-MP and H-Gn showed a decreased angle (P<0.01). The hyoid bone position of young patients with Angle class Ⅲ malocclusion treated using classic appliance FR Ⅲ, H-FH, H-S, and H-Ptm had an increased angle (P<0.05). Moreover, the hyoid bone position of those treated using Ar-H-Me had an increased angle (P<0.01), and the hyoid bone position of those treated using H-MP and H-RGn had a decreased angle (P<0.05).

CONCLUSIONSCompared with the hyoid bone position before treatment, the hyoid bone position after treatment of the young patients with Angle class Ⅲ malocclusion treated using improved appliance FR Ⅲ may move backward and downward, and the mandibular and hyoid bone position may move through clockwise rotation. The mandibular and hyoid bone position of young patients with Angle class Ⅲ malocclusion treated using classic appliance FR Ⅲ obtained a large angle by moving clockwise. The man-dibular bone moves backward and downward, thereby improving the hyoid bone in backward and upward directions. This condition makes a significant difference in treating the hyoid bone position of young patients with functional Angle class Ⅲ malocclusion.
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Humans ; Hyoid Bone ; Malocclusion, Angle Class III ; Mandible

A double labial-arch retaining appliance to retain the treatment effective of Class III osteal malocclusion were introduced and used to retain 60 patients with Class III osteal malocclusion. At the same time, 60 patients with Class III osteal malocclusion were retained with conventional Hawley retainer as the control group. The results indicated that the double labial-arch retaining appliance has good effect to the retain of Class III osteal malocclusion.
Cephalometry ; Humans ; Male ; Malocclusion, Angle Class III ; Orthodontic Appliance Design