ABSTRACT
Objective: To detect the clinical effect of T win-Block appliance in the treatment of the patients with Class II division 1 malocclusion, and to provide the basis for clinical treatment. Methods: A total of 30 patients with class II division 1 malocclusion were treated with Twin-Block appliance. The variables of the patients before and after treatment were measured with Ricketts cephalometric radiographys. Results: Compared with before treatment, the length of corpora mandibulae (Xi-Pm) of the patients after treatment was increased by 2. 50 mm (P<0. 05), the SNB angle was increased by 2. 58° (P<0. 05), and the ANB was decreased by 2. 71 (P<0. 01); the molar relationship distance and the Overjet were decreased by 2. 81 mm and 3. 68 mm, respectively (P<0. 01); the Ll-OP was decreased by 1.89 mm, the distance of Ll-APog was increased by 1.84 mm, and the angle Ul-APog was decreased by 7. 35° (P<0. 01); the Ls-TVL was increased by 1. 85 mm, the Sm-TVL was increased by 2. 12 mm (P<0. 05), and the Pos-TVL was increased by 2. 89 mm (P<0. 05). Conclusion: The Twin-Block appliance could obviously promote the development of mandibular bone, upright the anterior teeth and improve the lip angle of upper anterior teeth and the proflie in the treatment of the patients with class II division 1 malocclusion in the growth development period.
ABSTRACT
Objective To compare the X-ray cephalometric results of teeth and skeleton relationship between individual lingual orthodontic and labial straight wire orthodontics,and to provide reliable theoretical foundation for selecting orthodontic system in clinic. Methods The general conditions of the patients, classification of malocclusion,severity of denture crowding and orthodontic design were used as the selection criteria. Thirty familiar adult patients with malocclusion in clinic were divided into two groups randomly:individual lingual orthodontics group (A group)and labial straight wire orthodontics group (B group),15 cases in each group.X-ray cephalometrics were taken using Steiner and Tweed cephalometrics analysis,the results of analysis were compared between pre-treatment and post-treatment in two groups respectively, and the course of treatment in two groups was compared,too.The difference of treatment effect and course of treatment between two different orthodontic systems was evaluated.Results The relationship of first molar and canine of the patients in two groups was neutral relationship,overbite and overjet of anterior teeth was shallow,the teeth arrangement was orderly and no space was left after treatment.There was no statistically significant difference (P>0.05)between two groups in each measured values detected by Steiner Analysis after orthodontic treatment;there was no statistically significant difference (P>0.05)between two groups in each measured value detected by Tweed Analysis after orthodontic treatment;and there was no statistical significance (P>0.05 )in the D-values of Steiner Analysis and Tweed Analysis between two groups before and after treatment.The duration of treatment of the patients in two groups had no significant difference (P>0.05).Conclusion Both individual lingual orthodontics and labial straight wire orthodontics could obtain well teeth arrangement and occluding relationship and achieve satisfying clinical orthodontic outcome.
ABSTRACT
Objective:To study the related factors of landmarks identification repeatability in the computer monitoring. Methods:Totally 30 lateral cephalograms were selected at random, and the landmarks were identified by 2 orthodontists with the computer monitor twice. The data were obtained and the differences were analyzed. Results:There were differences in inter-operator and intra-operator in their coordination. The operators were similar to each other within a certain range. There were significant differences between the data of the abscissas and ordinate in some landmarks. Conclusion:The repeatability of identified landmarks is closely related to the location of the landmarks, the landmarks identification by human eyes and the quality of the X-rays.