ABSTRACT
Objective:To localize the impacted maxillary canine and to observe the root resorption of adjacent incisor in 3 dimen-sions using cone beam computed tomography(CBCT).Methods:92 impacted maxillary canines in 63 patients were scanned by CBCT.The three-dimensional images were obtained by multiplanar reconstructions(MPR).The cusp tip of each impacted canine was localized and set to the X,Y and Z planes after the observation of sagittal,coronal and axial views.The root resorption of adjacent in-cisors was observed.Results:In the X-axis,92% of impactions were mesial by 1 0.4 to 1 5.1 mm,8% distal by 2 to 5 mm;in the Z-axis,60% of impactions were palatal by 1 to 4 mm,40% buccal by 0 to 4 mm.41 .3% of the impacted canines were without root resorption of adjacent incisor,36.5% with slight,1 4.3% with moderate and 7.9% with severe root resorption of the adjacent inci-sor.Conclusion:The most frequent location of impacted maxillary canine is palatal and mesial with high incidence of root resorption of adjacent incisor.
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Objective To observe the clinical features and to identify γ-secretase gene mutations in a Chinese family with follicular occlusion triad (FOT).Methods Clinical evaluation was carried out in a family with FOT through field investigation.Peripheral blood samples were obtained from the family members and 100 unrelated healthy controls.DNA was extracted from the blood samples,and PCR was performed to amplify all the coding regions of PSEN1,PSENEN and NCSTN genes followed by DNA sequencing and comparative analysis.Results There were 14 members over 3 generations in this family,of whom,6 (4 males and 2 females) were affected by FOT.FOT was inherited in an autosomal dominant manner in this family.Clinical manifestations varied greatly among the 4 surviving affected members.DNA sequencing revealed a novel missense mutation,c.647A ＞ C (p.Q216P),in the exon 6 of NCSTN gene in the proband,which was cosegregated perfectly with affected,but not with unaffected,members in the family.The mutation was not found in any of the unrelated controls and had not been registered in the single nucleotide polymorphism (SNP) database in NCBI.Conclusions There is a novel heterozygous missense mutation,c.647A＞C in the exon 6 of NCSTN gene,which may be the molecular basis of pathogenesis of FOT in this family.
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Objective; To evaluate the efficacy of Twin-block appliance in Class Ⅱ division 1 of adolescents. Methods: Several e-lectronic databases (PubMed, The Cochrane library, Embase, CBMdisk, CNKI, VIP)were searched. Abstract that appears to fulfill the initial selection criteria were selected by consensus and original articles were retrieved. Five Chinese journals were hand searched for possible missing articles. Randomized controlled trials(RCTs) that evaluate the efficacy of Twin-block appliance in Class Ⅱ division I adolescents without any surgical intervention or syndromic characteristics were considered. A comparable untreated control group was required to factor out normal growth changes. The quality of included studies was evaluated according to Cochrane Reviewers Handbook 4.2.6 Meta-analysis was performed by using RevMan 5.0.0 software. Results: Four RCTs including 289 patients were identified. The results of our meta-analysis showed a significant increase on SNB angle, Ar-Gn, Nasolabial angle and Labial-mental fold compared with control group(P<0.05). Whereas overjet, overbite, ANB angle and Ls-E had a significant decrease. In addition, SNA angle and Li-E didnt show statistical significant changes(P>0. 05). Conclusion; In Class II division 1 of adolescents, Twin-block appliance can effectively decrease their overjet, overbite, ANB angle, and induce anterior-posterior growth of mandible. The effect on restrain forward growth of the maxilla was unclear. More RCTs are required to evaluate the efficacy of Twin-block appliance.