Comparison of the registration methods for the three-dimensional facial scans applied to the design of full-arch implant supported restoration / 北京大学学报(医学版)

OBJECTIVE@#To compare the registration accuracy of three-dimensional (3D) facial scans for the design of full-arch implant supported restoration by five methods and to explore the suitable registration method.@*METHODS@#According to the criteria, ten patients with maxillary edentulous jaw or end-stage dentition requiring implant supported restorations were enrolled in this study. A special rim with individual feature marks reflected appropriate occlusal relationship and esthetic characteristics was made for each patient. Both 3D facial scan data of natural laughter and with opener traction to expose the teeth or occlusal rim of each patient were acquired by facial scan and input to the digital analysis software Geomagic Qualify 2012. The dataset was superimposed by five different methods: seven facial anatomical landmark points alignment, facial immobile area alignment (forehead and nasal area), facial anatomical landmark points and immobile area combining alignment, facial feature points alignment, facial and intraoral feature points alignment with the same local coordinate system. The three-dimensional deviation of the same selected area was calculated, the smaller the deviation, the higher the registration accuracy. The 3D deviation was compared among the three registration methods of facial anatomical landmark points, facial immobile area alignment and the combination of the above two methods. Friedman test was performed to analyze the difference among the three methods (α=0.05). The effect of the aid of the facial and intraoral feature points were evaluated. Paired t test were performed to analyze the difference (P<0.05).@*RESULTS@#The average three-dimensional deviation of the selected area after alignment with the facial anatomical landmarks was (1.501 2±0.406 1) mm, significantly larger than that of the facial immobile area best-fit alignment [(0.629 1±0.150 6) mm] and the combination of the two methods[(0.629 1±0.150 6) mm] (P < 0.001). The aid of the facial feature points could significantly reduce the deviation (t=1.001 3, P < 0.001). There was no significant statistical difference in the remaining groups.@*CONCLUSION@#The forehead area of the 3D facial scan can be exposed as much as possible. The establishment of facial characteristic landmark points and the use of the invariant area alignment can improve the accuracy of registration. It should be clinically feasible to apply three-dimensional facial scan to the design of full-arch implant supported restoration with the registration of the immobile area on the face especially the forehead area.

Effects of 16 week aerobic exercise on baPWV and ABI of middle-aged and elderly patients / 中国应用生理学杂志

OBJECTIVES@#To investigate the interventional effects of 16-week aerobic exercises on the elderly's arteriosclerosis and its mechanism.@*METHODS@#Twenty-seven elderly people with the average age of 62. 70 ±3. 26 joined a 16-week square dance/taijiquan exercise program that conducted 60 minutes each time, six times per week. Arterial stiffness and its related indexes such as systolic pressure(SBP), diastolic pressure(DBP), left brachial-ankle pulse wave velocity (L-baPWV), right brachial-ankle pulse wave velocity(R-baPWV), left ankle brachial index (L-ABI), right ankle brachial index(R-ABI), serum triglyceride(TG), total cholesterol(TC), high density lipoprotein cholesterol(HDL-c), low density lipoprotein cholesterol(LDL-c), superoxide dismutase(SOD), malondialdehyde(MDA) and glutathione peroxidase (GSH-Px) were detected at 3 time points including before exercise program, by the end of exercise for 8 weeks and 16 weeks.@*RESULTS@#① Compared with pre-exercise, the R-baPWV and R-ABI of the elderly people were decreased at the end of the 8 week, and the L-baPWV, RbaPWV, R-ABI and L-ABI were decreased significantly at the end of the 16 week. ②Compared with pre-exercise, SBP and DBP were declined markedly (<0.01, <0.05) at the end of the 8 week, SBP, DBP and pulse pressure were decreased significantly (<0.01, <0.05) at the end of the 16 week. ③Compared with pre-exercise, TC and LDL-c were declined markedly (<0.01) at the end of the 8 and the 16 week, and there was no difference of the level of TG and LDL-c between pre-exercise and post-exercise. ④There was no evident difference of serum level of SOD, GSH-Px, MDA between pre-exercise and post-exercise at the end of the 8 week. Compared with pre-exercise, the level of serum SOD, GSH-Px was increased evidently while the content of serum MDA was decreased significantly (<0.01).@*CONCLUSIONS@#Sixteen-week aerobic exercises could reduce baPWV and ABI levels, regulate blood pressure, blood lipids and lipid peroxides levels of the elderly evidently, thus improve the controlling quality of atherosclerosis.

Three-year clinical effects of a modified semi-fixed bridge on restoring a missing posterior tooth / 北京大学学报(医学版)

OBJECTIVE@#To observe the effects of a modified semi-fixed bridge to restore a missing posterior tooth for three years.@*METHODS@#In the study, 38 cases with a posterior tooth missed were chosen as experiment group. The inclusion criteria for these cases required that one abutment tooth be defected, and another abutment intact. The missed posterior tooth was restored with a modified semi-fixed bridge in which a metal wing retainer was applied to the intact abutment tooth and a full crown retainer was applied to the defected abutment tooth, and the non-rigid connector linked to the metal wing retainer and the pontic, while the rigid connector linked to the full crown retainer and the pontic. And 42 cases with same abutment conditions were chosen as control group. These control patients were treated with classical rigidly-fixed partial dentures. The clinical effects regarding the bridge survival, abutment conditions, and etc. were observed by examination.@*RESULTS@#The average observation time for experiment group was 40.3 months (from 9 to 60 months). One case failed with loose crown retainer after 7 months' usage. Another failed case was the same performance after 20 months' wearing. The restorations were rebounded after the inner face of crowns was treated, and they were used normally. No loose abutment and retainer, no decayed abutment teeth were found, and the marginal adaptations between retainers and abutment teeth were good. The average observation time of control group was 44.7 months(from 22 to 50 months). No secondary decays and loose abutment teeth were detected and the marginal adaptation of the retainers was good.@*CONCLUSION@#This modified semi-fixed bridge has similar survival rate and clinical effects to restore a missing posterior tooth when compared with the traditional rigidly-fixed partial dentures. But the long-term observation is required.