A novel cone-beam CT scanning technique for measuring periodontal soft tissues in the esthetic area.

PURPOSE: This study investigated and tested a novel cone-beam computed tomography (CBCT) scanning technique capable of obtaining clear contours of soft tissues in the esthetic area. METHODS: Twenty-three periodontally healthy participants underwent this novel CBCT scanning technique. Soft tissue morphological parameters were measured on the CBCT images obtained. Intraoral clinical data were also collected at the same locations, and the accuracy of the CBCT method was tested. RESULTS: The median (interquartile range [IQR]) of the supracrestal gingival tissue thickness as 0.91 (0.73-1.13) mm, and the thickness of the central incisors was significantly greater than that of the canines (P < 0.05). The median (IQR) of keratinized tissue thickness was 0.73 (0.55-0.91) mm, which also showed a significantly greater thickness in the central incisors than in the canines (P < 0.05). Bland-Altman analysis suggested that CBCT could be accurate for measuring soft tissues in the esthetic area. CONCLUSION: The novel CBCT technique described yields clear contours of soft tissues in the esthetic area without the need for auxiliary tools. Moreover, measurements of soft tissue morphological parameters on CBCT appear to be accurate.

Tracing PRX1+ cells during molar formation and periodontal ligament reconstruction.

Neural crest-derived mesenchymal stem cells (MSCs) are known to play an essential function during tooth and skeletal development. PRX1+ cells constitute an important MSC subtype that is implicated in osteogenesis. However, their potential function in tooth development and regeneration remains elusive. In the present study, we first assessed the cell fate of PRX1+ cells during molar development and periodontal ligament (PDL) formation in mice. Furthermore, single-cell RNA sequencing analysis was performed to study the distribution of PRX1+ cells in PDL cells. The behavior of PRX1+ cells during PDL reconstruction was investigated using an allogeneic transplanted tooth model. Although PRX1+ cells are spatial specific and can differentiate into almost all types of mesenchymal cells in first molars, their distribution in third molars is highly limited. The PDL formation is associated with a high number of PRX1+ cells; during transplanted teeth PDL reconstruction, PRX1+ cells from the recipient alveolar bone participate in angiogenesis as pericytes. Overall, PRX1+ cells are a key subtype of dental MSCs involved in the formation of mouse molar and PDL and participate in angiogenesis as pericytes during PDL reconstruction after tooth transplantation.

High expression of aryl hydrocarbon receptor (AhR) plays an important role in the formation of fibrous epulis.

OBJECTIVES: Epulis is considered to be a massive reactive lesion rather than a true neoplasia. AhR is thought to be associated with inflammation and development of neoplasms. Here, we aimed to observe the expression of AhR in fibrous epulis and explore its role and possible mechanism in the pathogenesis of epulis. MATERIALS AND METHODS: Epulis and normal gingival tissues were collected, and AhR expression was detected at the mRNA and protein levels by quantitative polymerase chain reaction (qPCR) and immunohistochemistry, respectively. The expression levels of proinflammatory cytokines and apoptosis-related factor genes in human periodontal ligament cells (hPDLCs) and human gingival fibroblasts (hGFs) transfected with AhR short interfering RNA (siRNA) or negative control siRNA, upon stimulation with lipopolysaccharide of Porphyromonas gingivalis (Pg-LPS), were then examined. Finally, the expression levels of the proinflammatory cytokines and apoptosis-related factor genes in the epulis tissues were observed by qPCR. RESULTS: AhR expression in fibrous epulis was significantly increased at both the mRNA and protein levels. The expression of proinflammatory cytokines and apoptosis-related factor genes in hPDLCs transfected with AhR siRNA was significantly decreased when stimulated with Pg-LPS. The same trends were observed for hGFs. The opposite trend was detected in the epulis tissues. CONCLUSION: AhR may be a key factor in fibrous epulis pathogenesis that acts by regulating the expression of BCL2 family genes and inflammatory factor-related genes.

Big data analysis of patients with periodontitis and factors influencing treatment behavior / 口腔疾病防治

Objective @#To study patient-related information and factors altering their decision making in periodontal treatment and treatment behavior via big data analysis of the electronic medical records and to guide better dental care service and improve periodontal treatment. @*Methods@# A retrospective study was performed in patients with periodontitis who visited the Affiliated Stomatological Hospital of Tongji University from 2014 to 2016. Based on the periodontal sequence treatment procedure, the treatment types were divided into six groups and were analyzed using multivariable regression analysis. Chi-square test was performed according to gender and age.@*Results@#Age, payment method, disease severity, exhibited statistically significant differences regarding their effects on patients’ treatment behavior (P ＜ 0.05). Men were more likely to have severe periodontitis than women (male 41.04%; female 31.85%), and use medical insurance more often as payment method (male 86.14%; female 83.74%) (P ＜ 0.05). Compared with the population under 35 years old, moderate and severe periodontitis accounted for a larger proportion (84.58%) in the population over 35 years old. The compliance of the population over 35 years old was poor. Less follow-up reviews were conducted (17.10%) and medical insurance was less often used (49.65%) in this population. The differences were statistically significant (P ＜ 0.05).@*Conclusion@#Moderate and severe periodontitis accounted for a larger proportion in the population over 35 years old. Patients over 35 years old tend to choose simpler treatments with lower compliance and frequency of revisits. This situation may be related to the lower proportion of medicare use in this population. The awareness and compliance of periodontal treatment protocols in people over 35 years old needs to be improved.

[Comparison of subgingival debridement efficacy of air polishing and manual scaling].

PURPOSE: To assess the efficacy of subgingival air polishing and traditional manual scaling in 3-6 mm pockets. METHODS: Patients with chronic periodontitis who were in the maintenance phase were randomly assigned to receive subgingival air polishing (experimental group) and manual scaling (control group) in 4 teeth with probing depths of 3 to 6 mm. Clinical variables including plaque index (PI), probing depth (PD), probing on bleeding (BOP) and gingival recession (GR) were recorded at baseline, 7 and 30 days post-treatment. "Pocket closure" [PD ≤ 4 mm and BOP⁻] was also calculated as supplementary data. The data of the 2 groups were compared using paired t test with SAS 8.2 software package. RESULTS: Thirty-one patients were enrolled and PI was 0.8 during the study. Both treatment procedures resulted in significant reductions of PD at day 7 (P<0.0001). BOP% had significant reduction in the experimental group at day 7 (P=0.0390), but there was no significant difference compared to baseline at day 30. Meanwhile, BOP% in the control group demonstrated downward trends during the study, and significant improvement at day 30. The percentages of sites of "pocket closure" significantly increased in both groups (P=0.0329 and P=0.0035, respectively). CONCLUSIONS: The study indicates that subgingival air polishing and traditional manual scaling are both effective for improving clinical variables during supportive periodontal therapy (SPT) in teeth with probing depths of 3 to 6 mm. But the results reveal no significant difference between the 2 modalities.

[The effect of vascular endothelial cells on the migration of periodontal ligament cells and gingival fibroblasts].

PURPOSE: To investigate the effect of human vascular endothelial cells (HUVEC) on the migration of human periodontal ligament cells (HPDLC) and human gingival fibroblasts (HGF) through a model mimicking periodontal wound healing or regeneration. METHODS: HUVEC, HPDLC and HGF were co-cultured using a Transwell system, while HPDLC or HGF was cultured independently as control. Chemotaxis assay was performed using cell culture inserts (0.8µm pore size) to assess the effect of HUVEC on HPDLC and HGF vertical migration at 24h. A scratch wound assay was performed to assess the effect of HUVEC on HPDLC and HGF horizontal migration at 0 h, 8 h, 16 h and 24 h. A round glass sheet assay was performed to assess the effect of HUVEC on HPDLC and HGF wound healing ability at 1d, 4d and 7d. The data was processed with SPSS 13.0 software package. RESULTS: At the round glass sheet assay, while HUVEC was present, the integrated option density (IOD) of HPDLCs and HGFs were significantly higher than each of the single culture (P<0.01). Results of chemotaxis assay and scratch wound assay showed that the cell number of HPDLCs and HGFs were significantly higher than each of the single culture while HUVEC was present (P<0.01), and the number of PHDLCs was significantly higher than HGFs on chemotaxis assay (P<0.01) but the result of scratch wound assay was on the contrary (P<0.01). CONCLUSIONS: The presence of HUVEC can promote migration of periodontal cells, and the effect is more prominent on HPDLC than on HGF in vertical migration and wound healing, while horizontal migration is more prominent on HGFs as contrast.