ABSTRACT
Objective@#Exploring the position and bone wall thickness characteristics of the maxillary central incisors in Southern Chinese adults to provide a clinical reference for the design of immediate maxillary central incisor implantation surgery.@*Methods@#The hospital ethics committee approved the study, and the patients provided informed consent. CBCT images of 990 adult patients (aged 20-79 years) from the Stomatology Hospital (January 2018 to December 2021) were categorized based on the dental arch form and age-sex groups. Sagittal CBCT images of the maxillary central incisors were used to measure the labial and palatal bone thickness wall at 4 mm the CEJ to apical, the middle of the root, and the angle between the tooth long axis and the long axis of the alveolar process, to compare the thickness of the labial and palatal bone walls in samples of male and female patients, and to explore the relationship between the angle between the tooth long axis and the alveolar process long axis in samples of male and female patients in different age groups (20-39 years; 40-59 years; 60-79 years).@*Results@#Significant differences were found in the labiopalatine side of the alveolar bone of the maxillary incisor root position. A total of 95.8% (948/990) of the maxillary incisors were positioned more buccally, 4.1% (41/990) were positioned more midway, and 0.1% (1/990) were positioned more palatally. The thicknesses of the bone wall at the CEJ of 4 mm below the palatal side, the middle of the root, and at the apex were greater (1.82 ± 0.56 mm, 3.20 ± 1.10 mm, and 7.70 ± 2.00 mm, respectively) than those at the labial side (1.21 ± 0.32 mm, 0.89 ± 0.35 mm, and 1.86 ± 0.82 mm, respectively), with statistical significance (P<0.05). Male bone wall thickness was generally greater than female bone wall thickness (P<0.05). The angle between the long axis of male teeth and the alveolar bone was 14.77° ± 5.66°, while that of female teeth was 12.80° ± 5.70°, with a statistically significant difference (P<0.05). The angle between the long axis of teeth and the alveolar bone in the 40-59-year-old group and the 60-79-year-old group was greater than that in the 20-39-year-old group, and the difference was statistically significant (P<0.05).@*Conclusion@#A total of 95.8% of adults in South China have maxillary central incisors with root deviation toward the labial bone cortex. The thickness of the labial bone wall is much thinner than that of the labial bone wall, which is the middle of the thickness of the root. In Southern Chinese adults, the angle between the upper central incisor and the long axis of the alveolar bone in males is greater than that in females, and the degree of the angle increases with age. It is recommended to pay attention to the thickness of the bone wall around the root and the angle between the teeth before immediate implantation surgery to choose a reasonable implantation plan.
ABSTRACT
Objective @# To investigate the clinical effects of micro implant anchorage nail and Ni-Ti coilspring to lower the elongation molar. @*Methods@#60 patients with the first maxillary molar elongation were divided into 2 groups. 30 of them were treated with micro implant anchorage nail and Ni-Ticoil spring to lower the molar (observation group), and the other 30 patients were treated with segmental arch to lower the molar (control group). The average lowering time, depth and pain degree of the 2 groups were compared. @*Results@#The average lowering time was faster and the overage lowering depth was greater in the observation group than that in the control group; the slight pain rate in the observation group was significantly higher than that in the control group (P<0.05), while the ratio of moderate pain and severe pain was significantly lower than that in the control group (P<0.05).@*Conclusion@# To lower the elongation molar with micro implant anchorage nail and Ni-Ti coilspring might have shorter course and less pain.
ABSTRACT
Objective@# To study the change of STAT1 expression in the anterior cingulate cortex on rats under orthodontic force, and to further explore the roles of STAT1 and related JAK-STAT1 signaling pathway in the mediation and regulation of pain during tooth movement. @*Methods@#112 male Sprague-Dawley (SD) rats (225±25 g) were used in this study. They were randomly divided into experimental groups (96 rats) and control groups (16 rats). All rats were installed bilateral maxillary device for tooth movement models. Rats in the experimental groups were applied 80g orthodontic force on both sides and were divided into six subgroup 4 h, 12 h, 24 h, 2 d, 3 d, 7 d, with 16 rabbits in each subgroup. The control groups were only installed the same orthodontic devices, without the application of orthodontic force. Brain tissue of the anterior cingulate cortex was isolated after 4 h, 12 h, 24 h, 2 d, 3 d, 7 d since experiment, and the expression level of STAT1 and p-STAT1 was analyzed with the method of immunofluorescence and PCR. @*Results @#For the immunofluorescence result, there was significant difference in STAT1 expression between control groups and different experimental groups at different time points in total (P < 0.05). The STAT1 expression amount in the 4 h group decreased significantly when compared with the control group (P < 0.05); to the 2 d group, the difference is still statistically significant (P < 0.01). 3 d group, 7 d group and control group had no statistically significant difference. The STAT1 expression amount in 4 h group, 12 h group, 24 h group was significantly lower than that in 3 d and 7 d groups, differences were statistically significant (P < 0.05). The STAT1 expression in the 2 d group was significantly lower than that of 7 d (42.35 ± 5.77) group, the difference was statistically significant (P < 0.05). There was significant difference in p-STAT1 expression between control groups and different experimental groups at different time points in total (F = 623.518, P < 0.05). The p-STAT1 expression amount in experimental groups were higher than that in the control group (P < 0.05). The p-STAT1 expression in 4 h group was lower than that in 12 h and 24 h group and higher than that in 2 d, 3 d and 7 d groups, of which the differences were statistically significant (P < 0.05). The p-STAT1 expression in 12 h group was lower than that in 24 h group and higher than that in 2 d, 3 d and 7 d groups, of which the differences were statistically significant (P < 0.05). For the PCR result, the expression of mRNA in STAT1 of experimental groups of 4 h, 12 h, 24 h, 2 d, 3 d, 7 d and the control groups were not statistically significant (P > 0.05).@*Conclusions @#After applying orthodontic force, the expression of STAT1 decreased transiently and the expression of p-STAT1 increased transiently. The reduction of STAT1 was probably caused by the phosphorylation of STAT1 and decrease in the translation level of STAT1, rather than changes in the transcriptional levels. The orthodontic pain might be related with the activation of STAT1 into phosphorylated STAT1.