Evaluation of temporomandibular joint space and condylar morphology in patients with anterior open-bite based on cone-beam CT / 口腔疾病防治

Objective@#To investigate the difference of the temporomandibular joint between patients with anterior open-bite and normal overbite with cone beam CT (CBCT).@*Methods @# Fifty-four patients with anterior open bites and 54 patients with normal overbites were selected from the Department of Orthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University from June 2014 to August 2020. Sagittal and coronal images of the temporomandibular joint were reconstructed with multiplanar reconstruction techique. The Kamelchuk method was used to measure the superior, posterior and anterior space of the temporomandibular joint, and the condylar morphology was divided into two types: normal and abnormal. The joint space and condylar morphology of the anterior open-bite group and the normal overbite group were statistically analyzed. The anterior open-bite group was divided into 3 subgroups: ① Ⅰ° open-bite (open bite distance < 3 mm), ② Ⅱ° open-bite (open bite distance ≥ 3 mm and ≤ 5 mm) and ③ Ⅲ° open-bite (open bite distance > 5 mm). The difference of overbite spaces of the temporomandibular joint was compared among these three subgroups.@*Results@#Compared to the normal group, no significant differences were found for the anterior and superior space of the temporomandibular joint in the anterior open-bite group (P > 0.05), but the posterior space increased significantly (P < 0.01). A total of 52.8% of patients in the anterior open-bite group had abnormal condyles, whereas 21.3% of patients in the normal group, overbite significant differences was found between the two groups (P < 0.01). Compared with patients with Ⅰ° and Ⅱ° openbite, the condyle of patients with III° open bites was more forward in the fossa (P < 0.05).@*Conclusion @#The position of the condyle in the fossa of patients with anterior open bites is more forward, and abnormal condylar bone is more common found.

Post-operative Stability of Counter Clockwise Rotation of the Mandibular Plane in Skeletal CIII with Anterior Openbite Patients

3degrees).CONCLUSION: This study evaluated the amount of horizontal relapse, and the degree of relapse. Stable results were obtained. Although there was no statistical significance between the degree of openbite and the amount of horizontal relapse, the group with a greater amount of openbite had a greater amount of relapse.

Central tongue reduction for macroglossia

Macroglossia can cause dentomusculoskeletal deformities, instability of orthodontic and orthognathic surgical treatment, and create masticatory, speech and airway management problems. To determine whether a reduction glossectomy is necessary, it will important to identify the signs and symptoms of macroglossia. Development of dentoskeletal changes directly related with tongue size, such as an anterior open bite or a Angle Class III malocclusion tendency, would indicate that reduction glossectomy may be beneficial. For reduction glossectomy, several techniques have been reported. However, in most techniques the tip of tongue is removed. So its excision causes the loss of most mobile and sensitive portion of the tongue, and creates ankylosed, globular tongue. To avoid such problems, central tongue reduction technique have been proposed. This article will introduce central tongue reduction for anterior openbite case associated with macroglossia.

Evaluation of skeletal stability after BSSRO in skeletal class III with anterior open bite

OR = 1mm). Serial lateral cephalometric radiographs were taken within 2 weeks preoperatively, within 1 week postoperatively and at a follow up period that ranged from 7 to 24 months postoperatively. All cephalometric radiographs were traced and digitized using the Quick ceph image Pro for analysis. And then, horizontal and vertical changes of reference points(B point, Pogonion, L1) were assessed by the linear measurements in millimeters on both axes. The results were as follows: 1. Mean horizontal relapses were 0.67+/-0.93mm (11%) at B point (P0.05). 3. The mean angular change of occlusal plane to SN was 0.24+/-1.19 (P>0.05) and that of mandibular plane to SN was 1.03+/-1.85 (P<0.05). 4. There was correlation between the extent of preoperative overbite and the postsurgical relapse at B point and Pogonion. 5. There was no correlation between the amount of surgically produced horizontal movement and the postoperative horizontal relapse at B point.

Postoperative stability and occlusal plane alternation by orthgnathic surgery of skeletal Class III malocclusion with anterior open bite / 대한치과교정학회지

The purpose of this study is to investigate the stability of counterclockwise rotation of mandible by sagittal split ramus osteotomy to correct the skeletal Class III malocclusion with anterior open bite. Twenty five skeletal Class III open bite patients(mean age 20.6 years) who were treated by the sagittal split ramus osteotomies with rigid fixation were examined in this study. Cephalometric radiographs were taken for ach patients preoperative(T1), early postoperative(T2), and late postoperative period(T3). Mean postoperative period(T3).Mean postoperative period was 8.0 months. Cephalomerric analysis was done and data from T1, T2, and T3 were analyzed statistically by paired t-test and pearson correlation analysis. The following results were obtained. 1. Mandibular plane angle decreased 2.9degrees and mandibular occlusal plane angle related to SN plane decreased 2.7degrees after orthognathic surgery(T2). At 6 months after orthgnathic surgery(T3), mandibular plane angle increased 1.0degrees, but mandibular occlusal plane angle did not changed. 2. The amount of horizontal relapse long time after orthornathic surgery(T3) was 1.6mm at B point and it was 22% of the total posterior movements. There was no vertical relapse in the anterior facial height. 3. The related factor with horizontal relapse at late postoperative period was mandibular plane angle(p<0.01). The related factors with decreasing posterior facial height were amount of mandibular setback(p<0.01), increasing of mandibular ramus height(p<0.01), and decrease of the mandibular plane angle during operation(p<.01). 4. There was no relationship between the amount of changes in mandibular occlusal plan angle during operation and the amount of relaspe after surgery.

Change of condylar position after orthodontic treatment of anterior open bite / 대한치과교정학회지

This study was aimed to evaluate the changes in condylar position when severe anterior open bite patients were treated with MEAW. The subjects consisted of 11 patients(21 TMJs) who visited the department of orthodontics in SNUH, having severe anterior open bite as a chief complain. They were supposed to wear the up and down elastics and MEAW after finishing the leveling. The condylar position was evaluated with individualized corrected tomography in centric occlusion taken before and after treatment. The results were as follows; 1. In the change of condylar position after treatment, there were no statistically significant differences in right and left TMJs. 2. In the change of condylar position after treatment, there were no statistically significant differences in each malocclusion groups. 3. There were no statistically significant differences in percent displacement of condyle between before and after treatment. 4. There were no statistically significant differences in the amount of change in condylar change.

An electromyograghic study of muscular activities of tongue and lip muscles in anterior open-bite / 대한치과교정학회지

The purpose of the present study was to investigate the difference of muscular activities of the tongue and lip muscles between anterior open-bite and normal occlusion during various function. Thirty eight subjects of 12.1-39.6 years were employed in this study: Eighteen subjects were anterior open-bites and twenty subjects were normal occlusions. During rest position, maximum effort of lip sealing, command swallow of saliva and sucking & swallowing of juice, the electromyographic datas of the genioglossus, superior longitudinal muscle of tongue, upper and lower orbicularis oris were recorded and integrated with Medelec MS 25 electromyographic machine. Lateral cephalometric radiographs were taken on all subjects for the analysis of tongue posture and size. All data were recorded and statistically processed. The findings of this study can be summerized as follows: 1. During the rest position, muscular activity of tongue was higher than that of lip muscle in open-bite, but no difference in normal occlusion group. 2. During the swallowing of juice, the activity of orbicularis oris was higher than that of genioglossus in open-bite. But the normal occusion was showed higher activity of tongue during the swallowing of juice. 3. The open-bite, compared to the normal occlusion, had higher value of tongue muscle activity during the rest position. 4. Compared to normal occlusion group, the open-bite had higher value of lip muscle activity during the sucking and swallowing of juice. 5. During the command swallow of saliva, the normal occlusion was showed harmonious swallowing pattern, but the open-bite showed much variation and disharmony in muscular contraction sequence, tended to absent of lip muscle activity. 6. At the lateral cephalometric radiographs, compared to the normal occlusion, the open-bite was showed lower tongue posture. But no difference was found in intermaxillary space. It is suggested that the open-bite, compared to the normal occlusion, had higher muscular activity of tongue during the rest position and various functions, showed lower tongue posture on the lateral cephalogram. In the development of anterior open-bite malocclusion, these factors may be an etiologic factor.

A cephalometric evalauation of anterior openbite malocclusions treated by multiloop edgewise archwire technique / 대한치과교정학회지

The purpose of this study was to evaluate the change of before and after treatment of anterior openbite malocclusions treated by Multiloop Edgewise Archwire technique. The openbite sample consisted of 4 male and 12 female adults, treated with nonextraction or third molar extraction. The normal sample consisted of 58 subjects, which have pleasing facial profile and normal occlusion and no experience of orthodontic or prosthodontic treatment. The 58 subjects of normal sample were subdivided by cephalometric vertical relationship of face. The 40 subjects, cephalometric vertical relationship of face was in normal range, classified as Normal Sample group 1. The 18 subjects, increased cephalometric vertical relationship of face, classified as Normal Sample group 2. The computerized cephalometric analysis was accomplished with 50 reference points for 22 skeletal measurements, 46 dentoalveolar measurements, 8 soft tissue measurements. Statistical analysis of the data was carried out with paired t-test, Student's t-test, and DUNCAN test using SAS(PC version). The results were as follows: 1. There were no statistically significant differences in skeletal measurement between before and after treatment. The major changes were in dentoalveolar region. 2. After treatment, the long axis of maxillary and mandibular posterior teeth were distally tipped-back, and uprighted to bisected occlusal plane. The interincisal angle was increased. 3. There were no statistically significant increase in the upper posterior dental height and statistically significant decrease in the lower posterior dental height. The upper anterior dental height was increased, but there was no statistically significant increase in the absolute upper anterior dental hight. The lower anterior dental height was increased. 4. After treatment, the maxillary occlusal plane to palatal plane angle and the mandibular occlusal plane to mandibular plane angle were statistically significant increased. Then, there were no statistically significant difference between after treatment group and normal sample group 2. 5. After treatment, the percentage of upper lip length to upper anterior dental height was decreased. Then, There were no statistically significant difference between after treatment group and normal sample group 2.