The purpose of this study was to compare the differences in cephalometric parameters after active orthodontic treatment applying mini-screw implants (G1) or transpalatal arches (G2) as anchorage in adult patients with bialveolar dental protrusion needing extraction of four premolars. A total of 34 Chinese patients (18-33 years) with bialveolar dental protrusion were randomly assigned to G1 and G2. Sliding mechanics and en-masse retraction of anterior teeth were applied to close extraction spaces. The changes in skeletal, dental and soft tissues were analyzed in both groups on lateral cephalograms before and after active orthodontic treatment. Independent samples and paired-samples t-tests were utilized to analyze the morphological changes in both groups. ANB angle was decreased in G1 and remained unchanged in G2 (P < 0.05). Upper incisors were retracted more in G1 than in G2 (P < 0.01). Upper incisors and molars were intruded in G1, but extruded in G2 (P < 0.01). Although the upper molars were found with no significant distalization (P > 0.05), there existed molars distalization in some patients. However, the maxillary molars in G2 were mesialized (P < 0.01). The intrusion of upper molars in G1 resulted in counterclockwise rotation of the mandible and decrease of SN-MP angle (P < 0.01). Upper lip linear measurements including UL-Y and UL-E were decreased more in G1 than in G2 (P < 0.05). Mini-screw implants provide absolute anchorage in vertical and sagittal directions. Better dental, skeletal and soft tissue changes could be achieved by mini-screw implants especially in hyperdivergent patients. Skeletal anchorage should be routinely recommended in patients with bialveolar dental protrusion.

ObjectiveMolar intrusion by mini-screw implantation can cause different degrees of root resorption. However, most methods (2-D and 3-D) used for evaluating root resorption have focused on the root length without considering 3-D resorption. The purpose of this study was to volumetrically evaluate root resorption using cone beam computed tomography(CBCT) after mini-screw implant intrusion.Materials and Methods1. The volumes of 32 teeth were measured using CBCT and laser scanning to verify the accuracy of CBCT. 2. Twelve overerupted molars from adult patients were investigated in this study. After mini-screw implants were inserted into the buccal and palatal alveolar bones, 150 g of force was applied to the mini-screw implants on each side to intrude the molars. CBCT images of all patients were taken immediately prior to intrusion and after intrusion. The volumes of the roots were calculated using the Mimics software program. The differences between the pre-intrusion and post-intrusion root volumes were statistically evaluated with a paired-samples t-test. In addition, the losses of the roots were statistically compared with each other using one-way analysis of variance at the P<0.05 level.ResultsNo statistically significant volume differences were observed between the physical (laser scanning) and CBCT measurements (P>0.05). The overerupted molars were significantly intruded (P<0.05), and the average intrusion was 3.30±1.60 mm. The differences between the pre-intrusion and post-intrusion root volumes were statistically significant for all of the roots investigated (P<0.05). The roots were sorted by volume loss in descending order as follows: mesiobuccal, palatal, and distobuccal. Statistical significance was achieved among the three roots. The average total resorption for each tooth was 58.39±1.54 mm3.ConclusionVolume measurement using CBCT was able to effectively evaluate root resorption caused by mini-screw intrusion. The highest volume loss was observed in the mesiobuccal root among the three roots of the investigated first molar teeth.

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Temporomandibular joint osteoarthrosis (TMJOA) is characterised by chronic inflammatory changes, with subsequent gradual loss of joint cartilage. NF-κB is a crucial transcription factor in the course of inflammatory and immune responses, which are involved in OA pathology activated by proinflammatory cytokines. Genistein is known to have anti-inflammation and modulation of metabolic pathways through repression of the NF-κB signaling pathway in inflammatory disease. But so far, studies on the effects of genistein on TMJOA are very limited. So, the purpose of this study is to investigate the protective effect of genistein against experimentally induced condylar cartilage degradation through downregulating NF-κB expression in created osteoarthritis rats in vivo. Male SD rats were created as temporomandibular joint osteoarthritis models and administered through oral gavage with low and high dosage genistein (30 mg/kg and 180 mg/kg, respectively) daily for 4 weeks. The morphological changes of the condylar cartilage were studied with HE and Masson staining. The expressions of p65 and inflammatory cytokines (IL-1β and TNFα) were detected using immunohistochemistry and real-time PCR. The results showed that experimentally created osteoarthritis reduced the condylar cartilage thickness of rats and increased the gene expression of cytokines (IL-1β and TNFα) and positive cells of p65. Genistein treatment had positive effects on the condylar cartilage renovation, while high dose genistein treatment had more significant effects on the reversing of OA changes and reduction of the expression of p65 and inflammatory cytokines (IL-1β and TNFα). The results indicated that high dose genistein treatment had obvious therapeutic effects on condyle cartilage damages of OA rats. The mechanism may be that genistein suppresses the NF-κB expression activated by inflammatory cytokines.