ABSTRACT
Objective:To analyze the biomechanical stress distribution on the sagittal fractured of the mandibular condyle(SFMC) fixed by double plates in 3 different ways.Methods:The fixation finite element models with double straight plates(SS),one straight and one L-form plates(SL),and double L-form plates(LL)were established.The biomechanical stresses on condyle were calculated with finite element analysis.Results:In the model of SS fixation the maximum equivalent stress (MES),maximum total displacement (MTD)and maximum total corner(MTC)of condylar stump were 525.475 MPa,0.902 2 mm and 0.260 1°;MES,MTD,and MTC on fractured free-end were 4.425 MPa,0.882 7 mm and 0.019 9°,respectively.In the model of SL fixation MES,MTD and MTC on condylar stump were 1 135 MPa,0.9367 mm and 0.126 1°;MES,MTD and MTC on fractured free-end were 2.656 MPa,0.887 1 mm and 0.016 9°,respectively.In the model of LL fixation MES,MTD and MTC on condylar stump were 2 208 MPa,0.923 8 mm and 0.172 2°;MES,MTD and MTC on fractured free-end were 14.66 8 MPa,0.876 6 mm and 0.018 1°,respectively.Conclusion:Double L plates fixation is a proper way for SFMC.
ABSTRACT
OBJECTIVE@#To study mutations in the GJB2 gene in Kazak patients with nonsyndromic hearing impairment from Xinjiang.@*METHOD@#One hundred and ninety-three cases of Kazak from the Xinjiang region, including 97 cases of hearing loss and 96 cases of normal people, were performed mutational analysis of the GJB2 coding region by PCR-direct sequencing.@*RESULT@#Eight kinds of mutation were found in the encoding region of hearing impairment group:12 cases of 35 delG homozygous, 5 cases of 79G>A homozygous, 8 cases of 79G>A heterozygous, 1 case of 79G>A heterozygous and 608T>C heterozygous, 5 cases of 79G>A heterozygous and 341A>G heterozygous, 4 cases of 235 delC heterozygous, 2 cases of 341A>G heterozygous, 1 case of 439T>G heterozygous, 1 cases of 457G> A heterozygous, 2 cases of 521G>A homozygous. Four kinds of mutations found in the normal group were confirmed as common polymorphic mutation.@*CONCLUSION@#The study suggests that the GJB2 gene mutation of the Kazak deaf population in Xinjiang has ethnic and regional characteristics. There is a rather high carrier frequency of GJB2 mutation of Kazak patients in Xinjiang. In this study the 35 delG mutation is a common mutation of Kazak patients.