MTA is rarely applied in the repair of root fractured section. A case of maxillary second premolar which fractured ten years ago had been connected with MTA in this article and the cone beam CT was used to evaluate the treatment effect.
Bicuspid ; Cone-Beam Computed Tomography ; Glutamates ; Guanine ; analogs & derivatives ; Humans ; Pemetrexed ; Tooth Root

Objective: To evaluate the efficacy of Mtwo rotary instruments during root canal retreatment. Methods : Thirty mandibular premolars with oval root canal were prepared with ProTaper rotary instruments and obturated with lateral condensation method. The samples were divided into 2 groups. In Mtwo group, the filling materials were removed with Mtwo retreatment system and Mtwo basic instruments. Inmanual stainless group, the filling material were removed with manual instruments. The percentage of residual filling material was measured with image proplus software and the operating time was recorded. Results: The percentage of residual filling material in Mtwo group was significantly lower than manual group in middle third, but the opposite result can be found in the coronal third. In the whole canal, no significant difference was found between the two groups. The mean operating time in Mtwo group was significantly shorter than manual group. Conclusion Mtwo rotary instruments can shorten the time of retreatment, neither of the groups can remove the filling material in oval root canal completely.

Objective: To explore the role of apoliprotein D (APOD) in the proliferation and migration of human dental pulp cells (DPCs) and to provide a basis for the use of APOD to promote pulp regeneration. Methods: APOD expression in human dental pulp cells was inhibited by siRNA. The inhibition effect of APOD was confirmed by qPCR and Western blot. After APOD inhibition, colony formation experiments and CCK8 assays were employed to confirm the proliferation ability of dental pulp cells. Transwell assays were used to verify the cell migration ability after the inhibition of APOD expression. Results : After inhibiting APOD expression, the colony formation rate in the si-apod group was reduced compared with the NC group, and the difference was statistically significant (t=7.624, P=0.002). The CCK8 experiment showed that the OD value in the si-apod group decreased at 3, 5 and 7 d compared with that in the NC group (P < 0.05). Transwell results showed that the number of cell divisions was 57.25 ± 4.03 in the si-apod group and 154.50 ± 8.39 in the NC group, and the difference was statistically significant (t=10.45, P < 0.001). Conclusion Inhibition of APOD expression in dental pulp cells inhibits their proliferation and migration ability.

Objective: To investigate the association between interleukin-6 -572 gene polymorphism and aggressive periodontitis. Methods : A case-control study involved 83 patients with aggressive periodontitis (AgP) and 69 health controls was held, and the genotype and allele distributions of interleukin-6 -572 gene polymorphism were analyzed by PCR-RFLP. Results : There was statistically significant differences in the genotype distribution by the chi-square test in the two groups (χ2 = 13.710, P=0.001). The distribution of allele frequencies in AgP group was statistically different (χ2=13.213, P < 0.001) from the healthy control group, and the OR for the G allele is 2.988 (95%CI: 1.634-5.465) when compared with the C allele. Conclusion IL-6 -572 gene polymorphism is associated with the susceptibility to AgP in Chinese Han population of Guangdong, and the IL-6 -572 G allele might be a risk factor of the genetic susceptibility to AgP.

Objective : To analyze the morphology and incidence of middle mesial canal (MM) and isthmus in the mandibular first permanent molar by cone-beam computed tomography (CBCT). Methods: Statistical analysis was performed on images from patients who underwent CBCT examination in the Department of Radiology at Stomatological Hospital, Southern Medical University. Samples exhibiting root canal treatment, root resorption and calcification were excluded. Data regarding sex, age, the presence or absence of isthmus and MM, and the number of roots and root canals were recorded. Results : Of the 217 mandibular first molar samples, 8 (3.7%) had an MM, and 2 (0.9%) had an independent apical foramen. The overall incidence rate of isthmus was 57.1%; this rate was 50.7% in the cervical third of the root canal, 17.5% in the middle third, and 13.4% in the apical third. The incidence rate of isthmus was 61.8% on the left side, 52.3% on the right side, 58.7% in males, and 55.8% in females. No significant difference was found between the left and right sides or between females and males (P > 0.05). The incidence rate of isthmus in people under 60 was greater than 50% but was significantly lower in people older than 60. Conclusion Only a very small proportion of MMs have an independent apical foramen in the mandibular first molar. The incidence of isthmus in the mesial root of the mandibular first permanent molar is high, and isthmus usually occurs in the cervical third of the root canal. During root canal treatment or apical surgery, attention should be given to the physical and chemical preparation of the isthmus.