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Objective@# To analyze the correlation between third molar agenesis and craniofacial morphology by studying the location and number of congenital missing third molars and results of craniofacial cephalometric measurement. @*Methods@# A total of 123 patients were included, including 64 patients in the control group without congenital third molar absence and 59 patients in the absence group with at least one third molar absent. Cephalometric measurements included FMA, IMPA, AR-Go, GoGn-Sn, Co-A, Co-Gn, ANS-Me, Go-Me, SN-MP, Ar-Go-Me, SNA, SNB, ANB, Y-axis angle, Y-axis length, Ar-Go, Go-Me, MP-OP, FH-PP, FH-OP, a total of 18 bone tissue indicators, U1-SN, U1-L1, U1-NA, L1-NB, U1-APo and L1-APo, a total of 6 dental indicators, and UL-EP, LL-EP and nasolabial angle, a total of 3 soft tissue indicators. The correlation between congenital agenesis of third molars and craniofacial morphology was analyzed. @*Results@# The most common missing location of the third molar occured in the upper jaw and the most common number of missing teeth was one. In control group, Ar-Go-Me and SN-MP were larger (P<0.05), U1-SN, U1-NA, L1-NB, UL-EP and LL-EP were larger (P<0.05), and U1-L1 was smaller (P<0.01). There were no significant differences in Ar-Go and Go-Me between the two groups(P>0.05). @*Conclusion @#Patients with four third molars are more likely to have backward and downward rotation of the mandible and are more likely to develop into a convex facial type than patients with missing third molars, which has a higher correlation with hyperdivergent growth pattern and convex facial type.
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Objective To develop a Class Ⅲ twin-block magnetic orthopedic appliance (TMOA-Ⅲ) and to investigate the treatment effects of this appliance on skeletal Class Ⅲ malocclusion of mixed dentition and early permanent dentition.Methods The sample consisted of 76 Chinese children (42 males and 34 females,mean age 9.1 years) with Class Ⅲ malocclusion caused by maxillary retrognathism,and the subjects were divided into a treatment group and a control group.The treatment group,38 subjects (21 males and 17 females),were instructed to wear TMOA-Ⅲ for 5-8 months (mean 7.5 months) and the control group,38 subjects (21 males and 17 females),did not wear any appliance.Cephalometric radiographs were taken and measurement data were used for analysis.Results Compared with the control group,patients of the treatment group showed a favorable increase of maxilla length and anterior movement (PNS-A,P＜0.001;SNA,A-NPg,P＜0.05),and skeletal Class Ⅲ facial profiles improved (UL-EL,NsPgs-HL,Facial convexity,P ＜ 0.001;LL-EL P ＜ 0.005).Conclusions The results indicate that TMOA-Ⅲ is effective for the treatment of Class Ⅲ malocclusion caused by maxillary retrognathism in mixed dentition and early permanent dentition,which provides another choice for the treatment besides the face mask.
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@#BACKGROUND. The aim of this study was to analyze craniofacial sagittal and vertical dimensions in subjects with normal occlusions to establish age and gender-specific lateral cephalometric measurement standards for Mongolian children. MATERIAL AND METHODS. The study group consisted of a sample of 642 untreated subjects with normal occlusions from 6 to 15 year old. Craniofacial anatomic landmarks were identified directly on the digital images. A customized cephalometric analysis was used to measure 18 variables of linear measurement and 18 variables of angular measurement on software program (Winceph 11.0). Student’s t-test was employed to test for gender differences in each age. RESULTS. Most of the linear measurements, larger craniofacial distances were recorded in males than females. Also linear measurements were increasing according to age. There were no statistically significant gender differences with regard to most angular measurements at subsequent age groups. Soft tissue analysis revealed flatter profiles in females than in males from the age of 10-11 years onward, while age-dependent changes in the soft tissue profile were similar in both genders. СONCLUSION. In untreated subjects with normal occlusion craniofacial development of the hard can be considered age- and gender-dependent. Therefore age- and gender-specific differences of linear craniofacial distances should be taken into account for diagnosis and treatment planning in children and adolescents. The present results can be used as reference values for children and adolescents of Mongolian origin.
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Objective:To evaluate skeletal,dentoalveolar and soft tissue profile changes by activator therapy in patients with different skeletal patterns of Class Ⅱ1 malocclusions.Methods:22 subjects(10 girls,12 boys,mean age 11.5 ±0.67 years) in the mixed or early permanent dentition,were included and divided into low angle(n =15) and average angle(n =7) groups on the basis of skeletal pattern.All patients were treated with a traditional activator.The skeletal,dentoalveolar and soft tissue profile changes were compared on lateral cephalograms before and after treatment.Statistical analysis was performed with t-test of SPSS 13.0 at a level of significance of P ＜ 0.05.Results:Activator treatment in these growing patients resulted in a correction of the skeletal Class Ⅱ relationship (decrease of ANB,Wits and NA-Pg),an advancement of the mandibular structures(increase of Co-Pg and L1-APg),and changes of the teeth(increase of L6-MP).The changes of Wits,NA-Pg and L1-APg value of low and average angle groups were 1.34° ± 1.82 ° and 3.50 ° ± 1.77°,(3.06 ± 2.00) mm and (5.80 ± 3.17) mm,(-1.16-± 1.74) mm and (-2.83 ± 1.48) mm respectively(P ＜0.05).No statistical significance was found in the soft tissue profile changes whether intra-class or inter-group comparison.Conclusion:The activator appliance is effective in treating growing patients with mandibular deficiency,and mandibular reconstruction,in patients with average angle it is more effective than in those with low angle.
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OBJECTIVE: This study was designed to determine the most reliable cephalometric measurement technique in the normal population and patients with basilar invagination (BI). METHODS: Twenty-two lateral radiographs of BI patients and 25 lateral cervical radiographs of the age, sex-matched normal population were selected and measured on two separate occasions by three spine surgeons using six different measurements. Statistical analysis including intraclass correlation coefficient (ICC) was carried out using the SPSS software (V. 12.0). RESULTS: Redlund-Johnell and Modified (M)-Ranawat had a highest ICC score in both the normal and BI groups in the inter-observer study. The M-Ranawat method (0.83) had a highest ICC score in the normal group, and the Redlund-Johenll method (0.80) had a highest ICC score in the BI group in the intra-observer test. The McGregor line had a lowest ICC score and a poor ICC grade in both groups in the intra-observer study. Generally, the measurement method using the odontoid process did not produce consistent results due to inter and intra-observer differences in determining the position of the odontoid tip. Opisthion and caudal point of the occipital midline curve are somewhat ambiguous landmarks, which induce variable ICC scores. CONCLUSION: On the contrary to other studies, Ranawat method had a lower ICC score in the inter-observer study. C2 end-plate and C1 arch can be the most reliable anatomical landmarks.
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Humans , Odontoid Process , Pathology , SpineABSTRACT
The measurement and visualization of the roundness of the cranial circumference has not been attempted by the simple measurement device. That's why there has been a tendency that the morphologic cranial deformity can be diagnosed with accuracy only by the experienced physician. The accurate understanding of the roundness of the cranial circumference, however, is essential for the diagnosis and the decision of the treatment principle in cranofacial morphological deformity. Current methods, such as simple physical examination and/or the photography, are not enough to accurately express the roundness of the cranial circumference. In order to develop the new method of measurement, authors selected 16 points from the axial cutting plane of the cranium. These points can be selected under the same principle even though the axial plane changes. After measuring the distance of 16 points, the values are put into computer program. In conclusion, authors can retrieve the x, y coordinates of the 16 points and can show the intuitive roundness of the circumference of the selected axial plane of the cranium. This measurement tool will be helpful not only for the identification of the severity of the morphologic cranial deformity, but for the classification and the assessment of the result of the surgery.