Longitudinal measurements of tooth mobility following orthodontic treatment / 대한치과교정학회지

OBJECTIVE: The aim of the present study was to evaluate the changes in tooth mobility following orthodontic treatment and to obtain information regarding the guideline of retainer wear duration during the post-treatment period. METHODS: The sample consisted of twenty patients who had been treated with edgewise appliances. The mobility of the maxillary teeth from the central incisor to the first molar was measured bilaterally by way of the Periotest(R), a non-invasive, electronic device that provides an objective measurement of the reaction of the periodontium to a defined impact load. Tooth mobility was monitored at the time of the removal of the orthodontic appliances and subsequently at three-month intervals during the two years following appliance removal. RESULTS: Tooth mobility decreased rapidly for the first six months and then decreased at a slower rate during the next six months; no statistically significant decrease in mobility was observed during the second year following appliance removal. CONCLUSIONS: The results of the present study suggest that adequate tooth stabilization is critical during the first six months following appliance removal and that continued wearing of retainers is recommended at least until twelve months after the completion of orthodontic treatment.

What determines dental protrusion or crowding while both malocclusions are caused by large tooth size? / 대한치과교정학회지

OBJECTIVE: To examine the differences in lateral cephalometric characteristics between patients with dental protrusion and crowding in order to determine what factors affect dental protrusion or crowding while both malocclusion types are caused by large tooth size. METHODS: Twenty nine individuals with dental protrusion and 22 individuals with dental crowding were enrolled in this study. All subjects had larger teeth than average and Class I molar relationships. Craniofacial characteristics and hyoid bone positions were determined from lateral cephalograms and compared between the two groups. RESULTS: In the comparisons of craniofacial characteristics, the measurements indicating maxillary length and facial convexity showed greater values in the protrusion group than in the crowding group. Comparisons of hyoid bone positions showed that the hyoid bone was positioned more anteriorly and superiorly in the protrusion group than in the crowding group. CONCLUSIONS: The results of the present study indicate that some craniofacial characteristics and tongue position may affect the development of dental protrusion or crowding; when an individual has large teeth, dental protrusion or crowding might be determined according to maxillary growth and tongue position.