• Journal of Dental Rehabilitation and Applied Science
• /
• v.16 no.2
• /
• pp.93-104
• /
• 2000

Orthodontic treatment in conjunction with second-molar extraction has been a controversial issue among orthodontists over many decades. The aim of this study was to investigate the treatment effects of upper second molar extraction cases. The sample included 19 upper second molar extraction orthodontic cases(ten Angle's Class I's and nine Class II's, average age=13Y 6M) cared at Kyung-Hee University Department of Orthodontics. Lateral cephalometric radiographs were taken before and immediately after treatment. Seventy-nine points were digitized on each cephalogram and 38 cephalometric parameters were computed comprising 22 angular measurements, 13 linear measurements, and 3 facial proportions. The data obtained from each malocclusion group were analyzed by paired t-test. The statistical results disclosed that there was no significant change in skeletal pattern after treatment except for that accountable by growth while there was statistically significant change in dentoalveolar and soft tissue patterns. There were no significant changes in Bjork sum, posterior facial height /anterior facial height and lower anterior facial height /anterior facial height. No significant changes in anteroposterior position of maxilla and palatal plane were manifested. Although facial axis and lower facial height was slightly increased and the mandible was rotated backward and downward, there was no remarkable change in the mandibular plane. There were statistically significant changes in distal movement of upper first molar, molar key correction and overjet reduction while there was no change in the occlusal plane. The upper lip was slightly retracted simultaneously with slight increase in nasolabial angle. These results signify that distalization of upper dentition with the second molar extraction does change occlusal relationship without gross modifications in the craniofacial skeletal configurationson. Henceforth the second molar extracted would be recommended to treat severe anterior crowding and protrusion with minor skeletal discrepancy.

• The korean journal of orthodontics
• /
• v.30 no.2 s.79
• /
• pp.159-174
• /
• 2000

Many treatment approaches of Cl III malocclusion have been introduced and the choice of treatment should be a function of the individual problem, not of the clinician(personal preference, experience and success rate of the operator). Therefore a function of the individual problem should be analysed exactly Much has been written in the orthodontic literature concerning the nature of Cl III malocclusion. It has been reported by many investigators that a Cl III malocclusion occurs in a variety of skeletal and dental configurations by differences of race and age. Lateral cephalometric radiographs of 125 individuals were studied for the presence and distibution of four horizontal components and one vortical component in a manner similar to McNamara. The results were as follows : 1. Cl III malocclusion is not a single clinical entity. It can result from numerous combinations of skeletal and dental components. 2. Maxillary skeletal retrusion was the most common single charateristic of the Cl III sample. 3. Only a small percentage of the cases in this study exhibited maxillary dentoalveolar protrusion. 4. Only a small percentage of the cases in this study exhibited mandibular dentoalveolar retrusion. 5. Mandible was usually well-positioned, but a wide variation was observed. 6. A large percentage of the cases in this study exhibited excessive vertical development. Thus, it appears that in designing the ideal treatment regime, those approaches which might restrict vertical development and promote maxillary horizontal growth could be more appropriate in many cases.