A study of the changes in facial profile after orthodontic treatment. Part 1. Comparison between the improved group and unimproved group.

The purpose of this study was to investigate the harmonious facial profile before and after orthodontic treatment on permanent dentition and to determine the factors which influence lateral facial harmony. Materials were lateral Roentgen cephalograms from 150 subjects (25 males and 25 females each in 3 groups--maxillary protrusion, mandibular protrusion and crowding--) taken before and after treatment. The average age before treatment was 11 years and 6 months and, after treatment, was 14 years and 3 months. The term of active treatment was 2 years and 9 months. Lateral facial evaluation based on the external profile line was performed by a group of 40 persons which included dental students and the general public. In the 5 stage evaluation, each subject could receive from 40 to 200 points. The subjects with more than 121 points were classified in the harmonious group; those with less than 120 points were classified in the disharmonious group. Subjects who had been classified as disharmonious before treatment but became harmonious after treatment constituted the improved group. Subjects classified disharmonious before treatment who remained disharmonious after treatment constituted the unimproved group. The value of the overall harmonious group before treatment was 8.6% and, after treatment, was 36.6%. The increase in the percentage of cases classified as harmonious varied among the different occlusal types: for the mandibular protrusion, the value before treatment was 2% and after treatment was 32%, for crowding it was 18% before and 46% after treatment, and for maxillary protrusion, it was 6% before and 32% after treatment. The ratio of percentage in the harmonious group increased on every malocclusion group after treatment, suggesting the importance of orthodontic treatment for improvement of lateral facial harmony. Before treatment, the morphological conditions in the improved group were more advantageous than those in the unimproved group.

A study of the harmonious profile in facial esthetics. Part 1. Descriptive statistics.

UNLABELLED: The purpose of this study was to investigate the relationship between a harmonious profile and normal occlusion, differences between good and poor groups, and the characteristics of a good group from normal occlusion group and after orthodontic treatment groups. The sample included 60 subjects with normal occlusion (normal subjects) and 88 after orthodontic treatment subjects (orthodontic subjects). Evaluators were 20 students and 20 orthodontists from Tokyo Dental College. For the purpose of profile evaluation, normal and orthodontic subjects were classified into 3 groups (good, mediocre, and poor) based in their external profile lines. Lateral Roentgen-cephalograms were used to measure hard and soft tissues. Mean values and Student's t-test were calculated statistically. RESULTS: 1. The frequencies of the good and poor subjects were similar in both normal subjects and orthodontic subjects. When considering the mediocre group, however, the normal subjects were more likely to have a better profile than the other subjects. 2. There were differences in hard tissues between the good group and the poor group in both the normal subjects and the orthodontic subjects, but only slight differences in soft tissues. 3. In the good groups of both normal and orthodontic subjects (all subjects), the edges of the upper and lower central incisors and upper and lower lips retruded, the ratio of upper facial height to total facial height was greater and the chin region was thicker than in the poor group. Additionally, in the good group of normal subjects, the maxilla protruded and the anteroposterior difference between the maxilla and mandible was larger.

Changes in oral functions and posture at rest following surgical orthodontic treatment and myofunctional therapy. Evaluation by means of video recording.

Fifteen adult patients with skeletal mandibular prognathism or openbite underwent surgical and orthodontic treatment, then received myofunctional therapy. Cephalograms, facial photographs and oral models were taken on each patient. Patients were then videotaped, frontally and laterally. Observations were made of forty different oral behaviors and oral rest posture. Changes in morphology, speech, and swallowing are described and evaluated.

Stability of occlusion after orthodontic treatment with tooth extraction in adult cases.

The purpose of this study was to evaluate stability of occlusion in adult cases at least 4 years after orthodontic treatment and to clarify parameters influencing this stability. The subjects were 25 cases (mean age: 19 y 8 m) who had been treated with Edgewise technique involving first-premolar extraction. During orthodontic treatment, decreases in the maxillary and mandibular incisors' irregularity index (Max.I.I. and Mand.I.I.), posterior movement of the upper and lower incisors, increases in upper incisal height, decreases in lower incisal height, and increases in upper and lower canine width were noted. In the posttreatment period, increases in Max.I.I. and Mand.I.I., anterior movement of incisors, increases in incisal height, and decreases in canine width were observed. The amounts of overjet and overbite decreased during the treatment period and increased during the post-treatment period. Multiple regression analysis was useful to deduce which parameters influenced stability of occlusion after orthodontic treatment.

An orthodontic study of temporomandibular joint disorders. Part 2: Clinical research in orthodontic patients.

The purpose of this survey was to investigate the symptoms of temporomandibular joint disorders (TMD) in orthodontic patients and to define the relationships between symptoms and malocclusion and/or orthodontic treatment. The subjects were 532 patients, 6 to 38 year old Japanese, in the orthodontic department of Tokyo Dental College Hospital. They were examined for past or recent TMJ sounds, pain in the TMJ area, and abnormal jaw movements. The prevalence of TMJ symptoms was 33.8%. Sex differences were not statistically significant. The prevalence of TMD symptoms increased with age. TMD symptoms in young orthodontic patients (6-18 years old) were more common than in untreated subjects. Posterior crossbite and open bite patients had a high prevalence of symptoms.

Changes in oral functions and muscular behavior due to surgical orthodontic treatment.

The faces of fifteen adult patients who had undergone surgical orthodontic treatment were videotaped frontally and laterally in order to observe their oral circumferential behavior for function and their facial muscle posture at rest. As the ANB angle became 0.9 degrees from -3.5 degrees and the occlusal relationship improved to normal, facial morphology became harmoneous. In general observation, habits of facial muscle tensity at rest was reduced and lip sucking following forward tongue thrusting was decreased after treatment. Pronunciation of previously unclear sounds such as 'Ta' and 'Sa' improved and breath leakage decreased after treatment. The cooperative motions between lips and tongue improved significantly. Although a few subjects still had weak lip tensity and facial muscles, habits of tongue thrusting during swallowing were generally reduced and swallowing motions became more natural. As the movement of tongue tip became smoother, rhythmical chewing improved, and they became capable of chewing on both sides. Good relationships between morphology, oral function, and muscular behavior are very important in stabilization of the normal dentition after surgical orthodontic treatment. Normally maintained forces of balanced occlusion reduce the possibility of relapse.

An orthodontic study of temporomandibular joint disorders. Part 1: Epidemiological research in Japanese 6-18 year olds.

Malocclusion is considered one of the etiological factors of temporomandibular joint disorder (TMD). The purpose of this study was to investigate the prevalence of TMD and the relationship between TMD and the type of occlusion. The sample consisted of 7337 Japanese children, 6-18 years old, 3219 boys and 4118 girls. TMD symptoms were recorded as well as the type of occlusion in children with TMD. The prevalence of TMD overall was 12.2%. The prevalence increased with age and was slightly higher in girls (13%) than in boys 11.1%. This difference was not statistically significant. Joint sound as the only symptom was more common in younger subjects. TMD symptoms seemed more complicated with age when pain and abnormal jaw movement combined with sound. Joint sound was the most common symptom (89.3%), followed by the combination of sound and pain (2.2%). The incidence of other symptoms was under 1%. In subjects with TMD, 24.9% exhibited crowding, 20.1% had excessive overjet, 6.8% deep bite, 6.3% edge-to-edge bite, 5.6% anterior crossbite, 5.4% open bite, and 3.8% posterior crossbite. Morphologically normal occlusion was observed in 27.1%. In this study, many subjects with TMD had malocclusions. Early treatment may be important in the prevention of severe TMD. Although those with morphologically normal occlusions were included, a more detailed study concerning other causes of TMD is needed also.

[Longitudinal observation of condylar position in anterior crossbite at the mixed dentition during orthodontic treatment].

We investigated the condylar position by transcranial radiography which can be put daily clinical use easily. The patients are 8 anterior crossbite at the mixed dentition (4 functional crossbite and 4 skeletal crossbite). We observed their condylar positions before treatment (average age is 9.3 years old), after correction of overbite (average age is 10.0 years old) and 3-4 years after correction of overbite (average age is 14.0 years old). The results were as follows: 1. Condylar position of 7 cases changed after correction of overbite. The differences between right and left condylar position of six in seven cases had been recognized before treatment decreased after correction of overbite. Their condylar position were stable during the observation period of 3-4 years after correction of overbite. The condylar position of the other one case closed to fossa and then relapsed 3-4 years later. 2. Condylar position of only one case hasn't changed during the observation. 3. In functional crossbite cases, there were some differences between right and left condylar position before treatment, but no differences after crossbite correction. In skeletal crossbite cases, there was no tendency of the changing on their condylar position through treatment. 4. The changing to same direction was observed in the decrease of differences on condylar position and in the result of frontal cephalogram analysis. 5. There wasn't special relationship between changing of condylar position and orthodontic appliances. 6. TMJ dysfunction was observed in the case which has significant difference in its condylar positions before treatment and in the other case in which difference was not corrected after treatment. We recognized the usefulness of transcranial radiography for orthodontic treatment.