Supernumerary tooth is common,but symmetrical supernumerary tooth on both sides is rare.A case of symmetrical supernumer-ary tooth of maxillary posterior teeth area is reported in this paper.

Dens invaginatus is an unusual malformation.The difficulty in recognizing a tooth with dens invaginatus frequently results in the delayed diagnosis followed by unpromising treatment outcome because the abnormality cannot be seen until the tooth is involved with pulp necrosis even apical periodontitis.The application of CBCT scanning and dental microscope is playing a significantly important role in both diagnosis and treatment of dens invaginatus.This paper presents 2 cases with dens invaginatus which were well diagnosed and properly trea-ted,reviews the pathology and intends to get the principle ideas for the diagnosis and treatment of dens invaginatus.

20 children aged 3 years ±3 months with dental caries were randomly divided into 2 groups(n =1 0).The caries tissue was re-moved by conventional bur and Er:YAG laser respectively without the use of mouth speculum,mouth gag and binding belts.In laser group the success rate of treatment at first visit and return visit was higher(P <0.05)and children's dental anxiety grad was lower(P <0.05).The Er:YAG laser is more effective in easing children's dental anxiety and in the dental treatment.

Objective:To examine the adiponectin level in gingival crevicular fluid(GCF)in patients of chronic periodontitis with dia-betes mellitus type 2.Methods:20 patients of diabetes mellitus type 2 with chronic periodontitis(DM&CP),20 of periodontitis(CP) and 20 health subjects(H)were included.The periodontal indexes (SBI,PLI,PD and AL)were measured,GCF samples were quan-tified by periotron 8000,the adiponectin content in GCF was tested by adiponectin ELISA kit.The relationship between the adiponectin level in GCF and the periodontal indexes of the DM&CP patients was analyzed statistically.Results:The adiponectin level in GCF in group DM&CP was significantly lower than that in the other 2 groups(P <0.05).The adiponectin levels in GCF in group CP and H were not statistically different.The adiponectin level in GCF was negatively correlated with PD and AL(P <0.05),but had no correlation with SBI and PLI(P >0.05).Conclusion:Decrease of adiponectin in GCF may play a role in the development of DM&CP.

Objective:To explore the expression of PD-1 mRNA and PD-L1 mRNA in peripheral blood mononuclear cells(PBMCs)of OLP patients.Methods:The peripheral blood lymphocyte subsets (CD3 +,CD4 +,CD8 +,CD1 9 +,CD1 6 ++56 +)and humoral immunity indexes (lgG,lgA,lgM,C3,C4)were detected in 36 patients with OLP by flow cytometry and nephelometry respectively.The expres-sions of PD-1 mRNA and PD-L1 mRNA in PBMCs of 36 patients with OLP and 1 8 healthy individuals(the controls)were detected by fluorescence quantitative PCR,the correlation of PD-1 mRNA or PD-L1 mRNA with the immune function of OLP patients was analysed. Results:In OLP patients the percentages of peripheral blood lymphocyte subsets (CD3 +,CD4 +,CD8 +,CD1 9 +,CD1 6 + +56 +)as well as the complement of C3 and C4 were lower(P <0.05),the percentages of CD1 9 +(B)and the level of lgMwere higher(P <0.05),the expression levels of PD-1 mRNA and PD-L1 mRNA in rPBMCs were higher(P <0.05)than in the controls.There was positive correla-tion between PD-1 mRNA and PD-L1 mRNA expression level.The expression level of PD-1 mRNA was negatively correlated with CD4 +,but positively with lgG,the expression level of PD-L1 mRNA was positively correlated with CD1 9 +.Conclusion:The up-regu-lation of PD-1 mRNA and PD-L1 mRNA in PBMCs is correlated with the immunity of OLP patients.PD-1 /PD-L1 pathway may play an important role in immune pathogenesis of OLP.

Objective:To analyse pros and cons of Shikani laryngoscope anatomically during nasal intubation.Methods:60 pa-tients,with ASAⅠ -Ⅱ,aged 1 9 to 29 years old,undergoing titanium plate and titanium screw removal surgery after orthognathia, were randomly divided into Shikani group (S group,n =30)and HC video laryngoscope group (V group,n =30).Successful intuba-tion rate of the first attempt,total time cost,nasal bleeding rate and the incidence of postoperative airway complications were compared. Results:Compared with group V,the time cost of group S was significantly lower(P <0.05).But the rate of successful intubation for the first attempt,nasal bleeding rate and incidence of complications were the same in both groups(P >0.05).Conclusion:Shikani la-ryngoscope is faster,less invasive with easy maintenance in nasal intubation.

Objective:To investigate the association between dihyrofolate reductase(DHFR)gene rs1 1 742688 polymorphism and non-syndrom cleft lip with or without cleft palate (NSCL/P)in northest Chinese population.Methods:PCR-restriction fragment length polymorphism(PCR-RFLP)was used to identify the rs1 1 742688 polymorphism of DHFR gene of 220 NSCL/P patients(inclu-ding 1 38 core families)and 1 80 healthy controls.Hardy-Weinberg test and SPSS statistical software were used to calculate the data, OR and 95% confidence intervalarents.Results:In case-contral analysis,there was no significant difference in TT genotype of rs1 1 742688 between NSCL/P subjects and the controls(χ2 =0.439,P >0.05)in.Conclusion:The polymorphism of rs1 1 742688 in DHFR gene is not associated with NSCL/P in northest Chinese population.

Objective:To analyze the 3D changes of pharyngeal airway in patients with skeletal Class Ⅲ malocclusion after rapid maxillary expansion(RME)and maxillary protraction.Methods:53 patients underwent orthodontic treatment with Hyrax palatal ex-panders and maxillary protraction.Cone-Beam computed tomography(CBCT)scan was taken before treatment(T0),after 1 6 d RME (T1 )and after about 5 month maxillary protraction(T2).Data were reconstructed into 3D model,sagittal and transversal measure-ments,cross sectional areas,volumes of the pharyngeal airway were computed.Results:After RME,the transversal measurements, cross sectional areas,volumes of nasal passage were increased(P <0.05).After maxillary protraction,the 4 nasopharyngeal measure-ments were increased(P <0.05).Conclusion:RME and maxillary protraction may increase pharyngonasal airway.

Objective:To study the influences of angled abutments connected with small diameter implants in anterior maxilla restora-tion.Methods:Simulation models of angled abutment with small diameter restoration in anterior maxilla were established,the biome-chanical properties of the models were studied by finite element method(FEM)analysis.Results:Following the increase of the abut-ment angle,the stress and strain of all parts increased linearly and more concentrated,while appropriate prosthetic crown could share some load.Cortical bone elastic deformation exceeded the threshold when the abutment angle was bigger than 8 °.Conclusion:With abutment angle increase,stresses and strains will increase and will be more concentrated,which is unfavorable for load conduction.Ap-propriate crown can reduce the adverse effects of angled abutment.Angled abutment should not be used for d 3.5 implant.

Objective:To evaluate the vomer development of cleft palate patients.Methods:38 patients over 1 4 years(averaged 23.4 years)of age with cleft palate and 76 controls of normal people(aged 22.8 year on average)were included.The 3D computed tomo-graphy reconstruction images of the bony nasal septum were measured.The development of the vomer was evaluated by comparing the L1 (the length of the lower edge of the vomer),L2 (the length from nasal spine to the point of the sella)and S (the approximate area of vomer)among deferent groups.Results:The L1 ,L2,and S of cleft palate patients were smaller than those of the controls(P <0. 05).Compared with the postoperative cleft cases,the S and L2 of preoperative cases were bigger(P <0.05).Conclusion:The vomer development is adversely affected by cleft palate.Not only the vomer-palate fusion is lower,but also the sutura between vomer and na-sal septum cartilage and ethmoid bone are short.And the latter is greatly influenced by surgical trauma.