[Clinical study of extraction treatment of Class II division I malocclusion with Empower self-ligating brackets].

PURPOSE: To evaluate and compare the treatment efficiency of Empower interactive self-ligating brackets and traditional brackets in Class II division I extraction patients. METHODS: Forty patients with Class II division I malocclusion were randomly divided into 2 groups. Twenty patients received Empower self-ligating technique (group A) and the other 20 patients received MBT technique (group B). Four first premolars were extracted and without any other anchorage devices added in both groups. The duration of treatment, the number of visits and chair-side time were recorded. Cephalometric analysis was performed before and after treatment. The data was analyzed with SPSS 13.0 software package for paired t test. RESULTS: Treatment time and number of visits in group A were more than in group B, but there was no significant difference between the 2 groups. Chair-side time in group A reduced 151.15s on average compared with group B. Significant changes were observed in both groups after treatment. Upper and lower anterior teeth retracted and convex profile improved.U1-SN, U1-NA, L1-MP, L1-NB, UI-PTV, LI-PTV, UL-EP, LL-EP decreased. Significant differences were found in UM-PTV between the 2 groups(P<0.05). CONCLUSIONS: Compared with traditional brackets, Empower self-ligating brackets can save chair-side time, control anterior teeth torque and posterior teeth anchorage effectively, but can not reduce the treatment time or number of visits. Supported by Youth Research Project of Shanghai Municipal Health Bureau(2010Y155).

[Research of soluble interleukin-1 and tumor necrosis factor receptor treatment in orthodontic tooth movement in rats].

OBJECTIVE: To investigate the effects of local injections of recombinant soluble human receptors on experimental orthodontic tooth movement in the rat. METHODS: 64 male Sprague-Dawley rats were observed. Starting at day 1, three groups of animals each received local injections of soluble interleukin-1 receptor II (sIL-1-R II ), soluble' tumor necrosis factor receptor I (sTNF-R I ) and their combinations. One group served as the control. The amount of tooth movement was recorded and selected tissue sections were stained with hematoxylin-eosin (HE) to observe the histological morphologic alterations of the periodontal tissues and also were stained with tartrate-resistant acid phosphatase (TRAP) histochemistry to analyze the changes of the amount and distribution of osteoclasts and odontoclasts. RESULTS: The time-depended histomorphology changes in each receptor group were similar to those in the control group, but the resorption of alveolar bone was slighter at each time point and the surface of root appeared no or a few cement resorption signs. On day 14, the TRAP-positive cells on the surface of alveolar bone and root were reduced by approximately 50% relative to those in the control group (P<0.05). Whereas statistical tests revealed there were no significant differences among the experimental groups (P>0.05). CONCLUSION: Local injections of recombinant human sIL-1-R II and sTNF-R I in the orthodontic tooth of rats could reduce the amount and velocity of orthodontic tooth movement and reduce the incidence of root resorption.

[Dentoalveolar characteristics in skeletal class I patients with excessive overjet].

OBJECTIVE: To investigate the dentoalveolar characteristics in skeletal class I patients with excessive overjet. METHODS: Ten cephalometric measurements of 60 skeletal class I patients with excessive overjet were analyzed. RESULTS: Compared with patients with normal overjet, 1-SN, 1-NA and MxAAH were significantly increased in excessive overjet group I (overjet: 3 - 5 mm) and 1-SN, 1-NA and MxAAH were significantly increased in excessive overjet group II (overjet: 5 - 7 mm). CONCLUSIONS: The protrusion and tipping of maxillary incisor, and absence of compensatory proclination of mandibular incisor may be the factors, caused skeletal class I excessive overjet. Increased height of anterior maxillary anterior alveolar process was the compensatory change in skeletal class I patients with excessive overjet.

[The preventive effectiveness in reducing tooth decay and decalcification of different concentration of fluoride toothpaste for orthodontic patients].

OBJECTIVE: To investigate the preventive effectiveness in reducing tooth decay and decalcification of different concentration of fluoride toothpaste for orthodontic patients. METHODS: 86 patients were divided into the first test group and the second test group. The patients of the first test group brushed tooth with 1.1% sodium fluoride and acidulated phosphate gel. The patients of the second test group brushed tooth with 0.243% sodium fluoride in a silica base. The extent of facial tooth decay and decalcification of the twelve upper and lower teeth from right cuspid to left cuspid was scored blindly and independently by four observers after 12 months of product use. The scores were rated either one (having tooth cavity/decalcification) or zero (no tooth cavity/decalcification). Four observer's readings were averaged per tooth, and then per patient for the two treatment groups. RESULTS: After 12 months of product use, the mean caries score of the first test group was 0.326, and the mean caries score of the second test group was 0.490. There was significant difference between them. CONCLUSION: A gel system containing 1.1% sodium fluoride and acidulated phosphate provides a clinically better efficacy in reducing tooth decay and decalcification than does a toothpaste containing 0.243% sodium fluoride in a silica base under and adjacent to orthodontic brackets used in orthodontic therapy.