ABSTRACT
The purpose of this study was to evaluate the relation between the treatment duration and cephalometric measurements and the PAR index in Class I malocclusion patients. In 100 Class I malocclusion patients, PAR score and cephalometric measurements were taken from study model and cephalometric radiographs and cephalmetric radiographs and analyzed statistically. The results of this study were obtained as follows: 1. Treatment duration was correlated with extraction and pre PAR index. 2.ANB, FMA,FMIA and IMPA exhibited positive correlation between pre PAR index and pretreatment cephalometric measurements. 3. 1 to FP exhibited positive correlation between post PAR index and posttreatment cephalometric measurements, and 1 to FP exhibited negative correlation. 4. 1 to SN, II A and 1 to FP exhibited positive correlation between % PAR reduction and the change of cephalometric measurements FMA, FMIA, WITS and UL, exhibited negative correlation. The results of this study indicate that PAR index taken from study model relate with items concerned with upper and lower incisors, and there are the tendency that pretreatment PAR index are larger in the patients with large ANB value and hyperdivergent face.
Subject(s)
Humans , Incisor , Malocclusion , RitodrineABSTRACT
The purpose of this study was to evaluate the effect of splinting methods on the rearrangement of periodontal fibers after experimental tooth movement. Orthodontic force was applied by placing closed coil spring between upper third incisor and canine in seven dogs, weighing 20kg or more. After 3 weeks of force application, 0.025 inch multistrand wire and polyethylene ribbon were bomded to each side, as a flexible and rigid splinting respectively in 6 experimental animals. The remaining one served as a control. Each two animals were sacificed at 4, 8 and 12 weeks after splinting respevticvely and prepared histologically for hematoxylin-eosin and Masson';s trichrome staining. The results of this study were odtained follows: 1. After tooth mocement, periodontal space was narrowed and periodontal fibers were thick on pressure side while elongated fibers were observed on tension side. 2. After 4 weeks of retention, the rearrangement of periodontal fibers was observed in the flexible splinting group, but not in the rigrd splinting group. 3. After 8 weeks of retention, the rearrangement of periodontal fivers was obwerved in both groups, but the difference could not be detected between two groups. 4. During the retention period, the rearrangement of periodintal fibers was faster in tension side than in pressure side. There results show that the rearrangement of periodontal fibers is also obtained by rigid splinting after tooth movement. It is suggested that the rigid splinting by polyethylene ribbon can be used as way of postorthodontic retention.
Subject(s)
Adult , Animals , Dogs , Humans , Incisor , Polyethylene , Splints , Tooth Movement Techniques , ToothABSTRACT
Among the radiographs for temporomandibular joint, transcranial radiograph is widely used for screening and diagnosing temporomandibular disorder because it has sharp image and it is easy to take. This study was performed to compare condylar position and image sharpness in standard and individually corrected transcranial radiographs using Accurad-200 headholder. Submentovertex view, Reverse-Towne view, Standard and individually corrected transcranial radiographs of 45 university students who were randomly selected were traced, measured and analyzed. The results were as follows: 1. The means of condylar axes and lateral slopes were 16.8degrees and 22.5degrees respectively. There were no differences between male and female or right and left side. 2. Individually corrected radiographs showed smaller posterior joint space and larger anterior joint space than standard radiographs, but superior joint space did not show a statistical difference between standard and individually corrected radiographs. 3. While a large number(42.2%) of the standard radiographs showed concentric condylar position, lots of(57.8) condylar positions were retropositioned in the individually corrected radiographs. 4. The image sharpness was inferior in the individually corrected radiographs to that of the standard radiographs.
Subject(s)
Female , Humans , Male , Joints , Mass Screening , Radiography , Temporomandibular Joint Disorders , Temporomandibular JointABSTRACT
Tongue posture at rest position of Class III malocclusion is very important in malocclusion and phonation. Because Class III malocclusion shows low tongue position, speech defect is commonly occured. This study was attempted to evaluate the correlationship between the tongue posture at rest position and during /s/ phonation and facial skeleton in centric occlusion. Thirty subjects with Class III malocclusion who had no orofacial defects such as cleft palate, medical history of neurologic pathology, hearing defect and any previous speech therapy were selected. Ninety sheets of lateral cephalometric radiographs taken at rest position, during /s/ phonation and centric occlusion were traced, measured and statistically analysed. The results obtained were as follows; 1. In Class III malocclusion, the posture of tongue was positively correlated with the position of hyoid body. The hyoid body was positioned anteriorly and inferiorly as the vertical facial skeleton was increased in centric occlusion. 2. In Class III malocclusion, the vertical position of tongue tip at rest position was not correlated with facial skeleton in centric occlusion, but the horizontal position had low correlation with mandibular body length, APDI, and 1 to SN. 3. In Class III malocclusion, there was the tendency that the dorsal position of the tongue was lowered as the vertical facial skeleton was increased. 4. In Class III malocclusion, the vertical and horizontal position of tongue tip during /s/ phonation was not correlated with facial skeleton in centric occlusion.