[Hard and soft tissue changes following the treatment of Class II division 1 malocclusion using twin-block appliance].

OBJECTIVE: To investigate the hard and soft tissue changes following the treatment of Class II division 1 malocclusion using Twin-block appliance. METHODS: 50 Class II division 1 malocclusion subjects whose handwrist radiographs were in FG-G stage were selected. One group (27 patients) was treated with Twin-block appliance, the other group (23 patients) was observed without treatment The acquired data of cephalometric of two groups were analyzed statistically with SPSS 11.0. RESULTS: Soft tissue changes, Ls-E, Li-E, U1-Stms, Stms-Stmi, NsLs-FH, LsNsLi, LsNsPg', the angle of H decreased. Sn-Stms, Stmi-Me', Ns-Me', Sn-Me', NsLi-FH, NsPg'-FH, A'Ls-FH, B'Li-FH, LiB' Pg', CmSnLs, GSnPg', the angle of Z increased, there was statistically significant difference (P < 0.05). Hard tissue changes, SNB, L1-NB, IMPA increased, ANB, U1-SN, U1-NA, FMIA decreased, there was statistically significant difference (P < 0.05). CONCLUSION: Sagittal relationship between upper- and lower-jaws is effectively improved after orthopedics with Twin-block appliance. Lower face height increases. Soft tissue profile tends to be straight-styled.

[Soft tissue changes following the treatment of Class II division 1 malocclusion using Headgear-activator appliance].

PURPOSE: To investigate the soft tissue changes following the treatment of Class II division 1 malocclusion using Headgear-activator appliance. METHODS: Fifty Class II division 1 malocclusion subjects who were at peak high velocity on the growth curve were divided into two groups. Standardized lateral cephalogram was taken for each patient in the two groups before and after treatment. SPSS11.0 software package was used to calculate the mean and standard deviation, matched t-test was used to evaluate the changes of the soft tissues. RESULTS: The angle of CmSnLs,LiB'Pg' and Z increased, the angle of H, LsNsLi and LsNsPg' decreased, there was statistically significant difference between the two groups. CONCLUSIONS: Using Headgear-activator appliances, soft tissue profile is effectively improved. Soft tissue chin is moved forward obviously. Lip protrusion is decreased.

[Bone histomorphometry study in agglutination of femoral condyle of dog after being compressed].

OBJECTIVE: This study simulated clinical implant surgery using squeeze technique by establishing a rational animal model. To measure the morphologic parameters in order to observe the agglutination of the cancellous bone after being compressed. The study wanted to get some favourable support of implant squeeze technique in bone healing and obtaining primary stabilities of implants, so as to provide some reasonable and valid guidance in the application and improvement of implant squeeze technique. METHODS: The cancellous bone in condyles of femur of dog had been chosen as the experimental position, prepared the implant holes using squeeze technique according to different compressing extent (0, 0.6, 1.2, 2.0 mm), and then inserted the corresponding implants into them. After different healing periods (1, 2, 4, 12 weeks), the mongrel dogs were sacrificed and the hard tissue slices were made and then the morphologic parameters were measured. RESULTS: The morphologic parameter of the bone tissue shows that after being compressed, the trabecular bone thickness was almost constant, while the trabecular bone number increased, and the trabecular bone spacing decreased, obviously in the 1-week and 2-week groups. The differences went down gradually along with the extend of healing time. CONCLUSION: The clinical implant surgery using squeeze technique can improve peri-implant bone density so it is good for obtaining primary stabilities of implants.

[Effect of early treatment with the Twin-block appliance].

OBJECTIVE: To evaluate the effectiveness of early treatment with the Twin-block appliance for the developing Class II division 1 malocclusion. METHODS: A Total of 30 children with Class II division 1 malocclusion, 18 (8 male, 10 female) out of which received treatment with the Twin-block appliance, the other 12 cases (6 male, 6 female) without treatment served as control group. Cephalometric data were collected at the start and the end of the study and statistical analysis were applied. RESULTS: Except the factor of growth, treatment with the Twin-block appliance resulted in reduction of ANB (1.55 degrees), overjet (5.46 mm) and correction of molar relationship (4.07 mm). These changes were due to the change of Pg/OLp, Co/OLp and mandibular length. The change of A/OLp was not significant. The skeletal effect contributing to the change on overjet and molar relation were 58% and 78% respectively. CONCLUSION: Early treatment with the Twin-block appliance was effective in reducing ANB angle, overjet and correction of molar relationship. The changes were mainly profit from the favorable skeletal change of mandible, especially from its length, while the effect on maxillary was not significant.