[The symmetry of nasal maxillary complex of patients with unilateral complete cleft lip and palate at the stage of mixed dentition-A cone beam CT study].

PURPOSE: To investigate the symmetry of nasal maxillary complex in the three-dimensional directions of patients with unilateral complete cleft lip and palate(UCLP) at the stage of mixed dentition. METHODS: Craniofacial cone-beam CT(CBCT) images of 20 UCLP patients at the stage of mixed dentition were selected. Three-dimensional reconstruction of bone tissue was carried out by Mimics software, nasal root point and 32 markers with the same name of the healthy side and the cleft side of the nasal maxillary complex were traced, three-dimensional reference planes were set up, then the distances between the points to the three-dimensional planes were measured respectively. SPSS 22.0 software package was used to analyze the data. RESULTS: In the horizontal direction, compared with the non-cleft side, the width of the cleft side of the maxilla at INM and SPC was smaller, the width of maxilla at LPA and SPr was larger, the differences were statistically significant (P<0.05). In the sagittal direction, compared with the non-cleft side, the depth of LPA, Maz and SPr at the cleft side was larger, the depth of SPM and SPC was smaller, the differences were statistically significant (P<0.05).In the vertical direction, the positions of LPA, INM and Maz at the cleft side was lower than the non-cleft side, SPC and SPr were higher, the differences were statistically significant(P<0.05). The remaining points had no significant difference (P>0.05). CONCLUSIONS: The nasal maxillary complex of UCLP patients at the stage of mixed dentition is asymmetric in three directions. The asymmetric locations were mainly located in the nasal cavity and alveolar bone. No obvious asymmetry is found in the orbital region and the maxillary region far from the cleft.

[Association between cervical vertebral maturation stages and dental calcification stages in patients with unilateral complete cleft lip and palate].

OBJECTIVE: The purpose of the study is to investigate the relationship between dental calcification stages (DCS) and cervical vertebral maturation stages (CVMS) in patients with unilateral complete cleft lips and palates (UCLP) and to provide a theoretical basis for the treatment time selection of cleft lip and palate (CLP) patients. METHODS: A total of 123 UCLP patients and 215 non-CLP subjects were selected. The DCS of the left mandibular canine, premolar, and second molar in non-CLP subjects and on both cleft sides of UCLP patients were assessed utilizing the Demirjian method. CVMS was observed utilizing the Baccetti method. The results were analyzed by Spearman rank correlation, and the correlation coefficients were compared. RESULTS: There was a correlation between the CVMS and the DCS of the left mandibular canine, the first premolar, the second premolar, and the second molar in the non-CLP subjects and on both cleft sides of the UCLP patients (r=0.762-0.864, P<0.05; r=0.809-0.914, P<0.05, respectively). The correlation between the CVMS and the DCS of the mandibular first premolar was highest among the UCLP patients. Except for the first and the second premolars of UCLP females, the correlation between the DCS and the CVMS of the other teeth did not differ among the non-CLP subjects (P>0.05). CONCLUSIONS: DCS can be utilized as a biological index to determine the growth development statuses. The correlation between the CVMS and the DCS of the mandibular first premolar was the highest.

Intermittent Stretching and Osteogenic Differentiation of Bone Marrow Derived Mesenchymal Stem Cells via the p38MAPK-Osterix Signaling Pathway.

AIMS: The relationship between the p38MAPK signaling pathway and osterix in osteogenic differentiation of BMMSCs subjected to intermittent stretching was investigated. METHODS: BMMSCs derived from C57BL/6J mice were divided into the following groups: 1) control, 2) stretch, and 3) SB203580+stretch (SB203580 is a p38MAPK signal pathway inhibitor). BMMSCs were exposed to an intermittent mechanical strain of 0.8% (8000µ strain) at 0.5 Hz, twice a day for 30 min each application. BMMSCs were harvested on days 1, 3, and 5 post-treatment. The expression of ALP, COL I, OCN, and osterix mRNA was assessed utilizing RT-PCR while the expression of P-p38MAPK and osterix protein was assessed by Western blot analysis. The osterix gene in mouse BMMSCs was knocked down using RNAi technology and its protein expression was also assessed by Western blot. RT-PCR was used to detect ALP, COL I, and OCN mRNA expression. RESULTS: Intermittent stretching was found to promote expression of ALP, COL I, OCN, and osterix mRNA. Silencing the osterix gene was found to reduce levels of ALP, COL I, and OCN mRNA. Western blot analysis demonstrated that the levels of osterix and P-p38MAPK proteins in the stretch group were significantly higher than in the control group (P<0.05). There was less expression of ALP, COL I, OCN, and osterix mRNA in the SB203580+stretch group than in the control and stretch groups. CONCLUSIONS: Data demonstrate that intermittent stretching promotes osteogenic differentiation of BMMSCs, and the p38MAPK-osterix pathway has an important role in the control of osteogenesis-related gene expression.

[Comparative study on the apical root resorption between self-ligating and conventional brackets in extraction patients].

PURPOSE: To explore whether orthodontic light force with self-ligating brackets can reduce the amount of external apical root resorption (EARR). METHODS: Thirty patients with Class I or II crowding malocclusion were selected. Four first premolars of all patients were extracted in orthodontic treatment. 15 patients were treated with self-ligating brackets (Damon 3MX) and 15 patients with conventional ligation brackets, respectively. Patients in two groups were comparable in gender, age, crowded degree and malocclusion classification at the commencement of treatment. EARR of the maxillary and mandible incisors was evaluated on panoramic radiographs and models taken before and after treatment, and measured in millimeters. Student's t test was performed using SPSS19.0 software package. RESULTS: Overall, no difference was found in the amount of EARR between the two groups. The amount of EARR in maxillary central incisor was (2.05±1.51) mm in Damon group and (2.08±1.21) mm in conventional group(P=0.973>0.05); (1.77±1.01) mm in maxillary lateral incisor in Damon group and (1.91±1.59) mm in conventional group(P=0.848>0.05); (2.06±1.62) mm in mandibular central incisor in Damon group and (1.98±1.50) mm in conventional group(P=0.926>0.05); (1.94±1.45) mm in mandibular lateral incisor in Damon group and (1.84±1.17) mm in conventional group(P=0.888>0.05). CONCLUSION: No difference should be expected for root resorption between self-ligating and conventional brackets in orthodontic extraction treatment.

[Correlation analysis on the malocclusion and articulation of skeletal angle III malocclusion in mixed dentition].

OBJECTIVE: To investigate the effects of skeletal Class III malocclusion in mixed dentition on speech articulation and to look for which factors lead to the speech errors. METHODS: Thirty-eight children with skeletal Angle Ill malocclusion in mixed dentition were selected as a sample group and 40 children with normal occlusion in mixed dentition as a control group. Two phoneticians evaluated their articulations and wrote down error phonemes respectively. The correlation analysis was undertaken between the number of errors and the measurements of patients' cephalometry. RESULTS: The number of errors were correlated significantly with overbite, UI-LI, OBJ (OB+OJ) and TD-PW. CONCLUSION: There is articulatory malfunction in the majority of skeletal Angle III malocclusion patients in mixed dentition. Articulatory malfunction is related to the position of incisors and the tongue.

[Changes in mastication efficiency before and after orthodontic treatment of adult skeletal angle III malocclusion].

PURPOSE: To evaluate the changes of mastication efficiency pre- and post-treatment in adult skeletal Angle III malocclusion, and to analyze the effect of malocclusion on mastication efficiency. METHODS: Masticatory efficiency was analyzed in 60 patients with adult skeletal Angle III malocclusion pre- or post-orthodontic treatment and 30 adults with normal occlusion as controls. Masticatory efficiency was measured by means of a spectrophotometer using Gelatin. SPSS 10.0 software package was used for Student's t test and step-wise regression. RESULTS: (1) Significant difference of masticatory efficiency was found among the three groups (P < 0.001). Multiple comparision showed significant difference among pre-treatment group, post-treatment group and normal controls (P < 0.05). (2) Step-wise regression results suggest that overjet and mandibular prognathism were closely related to masticatory efficiency in both pre- and post-treatment group. CONCLUSION: Orthodontic therapy can improve masticatory function in patients with malocclusion.

[Influence of different porcelain surface treatment method on the bonding of metal brackets to porcelain].

OBJECTIVE: To investigate the influence of different porcelain surface treatment methods on the shear bond strength of metal brackets bonded to porcelain. METHODS: 80 porcelain facets were divided randomly into two groups according to different adhesive material that was used to bond metal brackets. Adhesive material were Jing-Jin enamel adhesive and light-cured composite resin. Each group was further divided into 4 subgroups according to different surface treatment methods, which were acid etching with 37% phosphoric acid (H3PO4), acid etching with 9.6% hydrofluoric acid (HF), deglazing by grinding and silanating the porcelain surface. All specimens were stored in 37 degrees C water for 24 hours and then the shear bond strength and the porcelain fracture after debonding was determined. The porcelain surfaces after HF etching, H3PO4 etching and deglazing by grinding were examined by scanning electron microscopy respectively. RESULTS: The shear bond strengths in the HF etching groups, the deglazing groups and the silanating groups were much greater than that in the phosphoric etching groups (P < 0.01). Adequate orthodontic bonding strength was achieved both when bonded with light-cured composite resin after deglazing by grinding and when bonded with either of these adhesives after HF etching or surface silanating. There were no differences in the rates of porcelain fractures among groups (P > 0.05). CONCLUSION: HF etching, deglazing by grinding and silanating can all increase the shear bond strength between metal bracket and porcelain. Surface silanating of porcelain is a better surface treatment when metal brackets bonded to porcelain.

[A statistic analysis on absence of third molar germs in orthodontic patients].

OBJECTIVE: To examine the absence of the third molar germs in orthodontic patients and to evaluate the relationship between third molar germs and malocclusion. METHODS: The subjects comprised 234 patients (male 92, female 142) from the orthodontic clinic whose ages were 14-18. The assessments of the third molar germs were made from panoramic radiographs, and the assessments of ANB angle were made from lateral cephalograms. All the data were analyzed by statistic chi2 test. RESULTS: The percentage of male who missed one or more third molar gems (37.0%) was higher than that of female (24.6%). There was no significant difference between the absent frequencies of third molar germs on left and right sides in either maxilla or mandible. The absent percentage of third molar germs in skeletal III subjects was higher than those in both skeletal class I and II subjects. The absent difference of third molar germs was in upper arches (P < 0.05), but not in lower arches (P > 0.05). There was no significant difference in absent percentage of third molar germs between skeletal class I and II subjects. CONCLUSION: Male patients have higher absent frequencies of third molar germs than female ones. Skeletal class III patients have higher absence of third molar germs in upper jaws than skeletal class I and II patients.