Soft tissue image reconstruction using cone-beam computed tomography combined with laser scanning: a novel method to evaluate the masticatory mucosa.

OBJECTIVE: To construct a 3-D model of the masticatory mucosa to measure the thickness of the facial/lingual gingiva and palatal mucosa. STUDY DESIGN: Maxillofacial regions of 8 volunteers were scanned using cone-beam computed tomography to generate 3-D maxillary and mandibular models. Digital models were obtained by laser scanning of the impressions. Models were constructed using global data registration and Boolean subtraction. Accuracy was assessed by comparison against control patients with a periodontal pack around their gingival boundaries. Inter- and intra-observer variability were determined. RESULTS: Masticatory mucosa models (in stereolithography format) showed the gingival and mucosal contours. The gingival thickness of the 3-D models and controls were not significantly different (P > .05). The interclass correlation coefficient and Kappa values indicated good intra-observer and inter-observer agreement, respectively. CONCLUSIONS: Cone-beam computed tomography combined with laser scanning can be reliable for visualizing and measuring the thickness of the masticatory mucosa.

Osteogenic differentiation of human periodontal ligament stem cells expressing lentiviral NEL-like protein 1.

NEL-like protein 1 (NELL1) is a newly identified secreted protein involved in craniosynostosis and has been found to promote osteogenic differentiation of mesenchymal stem cells. The objective of this study was to investigate the effect of NELL1 on osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs) and the potential underlying mechanism. hPDLSCs underwent lentivirus-mediated NELL1 transfection (Lenti-NELL1) and markers of osteogenesis were assessed [alkaline phosphate (ALP), osteocalcin (OCN) and calcium deposition] to evaluate the effect of NELL1 on the differentiation of these cells. Quantitative polymerase chain reaction (qPCR) was employed to measure the mRNA expression of Msx2 and Runx2, and Lenti-enhanced green fluorescent protein (EGFP) served as a control. Western blot analysis and qPCR analyses confirmed that Lenti-NELL1-transfected hPDLSCs could express NELL1. Compared with the Lenti-EGFP group, ALP, OCN, calcium deposition and Msx2 mRNA expression were markedly increased (P<0.01), but there was no significant difference in Runx2 mRNA expression between the two groups (P>0.01). hPDLSCs can be transfected by Lenti-NELL1 and can stably express NELL1. NELL1 is able to promote the osteogenic differentiation of hPDLSCs, which may be related to the downregulation of Msx2 expression. Lenti-NELL1 transfection can be used during in vitro gene therapy for periodontal regeneration.

[Study on reference value of healthy teeth mobility of youth].

OBJECTIVE: This study aimed to establish the reference value range of healthy teeth mobility in Chinese youth. METHODS: 200 right side teeth of Han nationality of Chinese youths were measured so as to get the range of the parameters. RESULTS: All parameters of 14 teeth were achieved. The parameter of TM in mandibular incisor was the highest and in mandibular first molar lowest. CONCLUSION: It is very significant to get and quantify the healthy teeth's parameter range. Because they can be served as the healthy contrast when dentists diagnose the mobility. It also reflects the fact that lower the TM parameter is, firmer the tooth will be.

[Primary culture of human periodontal ligament fibroblasts by explants with enzymatic digestion].

OBJECTIVE: To increase the success rate of primary culture of human periodontal ligament fibroblasts (HPLF), and to establish an experimental model for studying HPLF in vitro. METHODS: The primary cells were isolated from human periodontal ligament by explants with enzymatic digestion method. Morphological analysis and immunocytochemical staining were used to characterize the cell lineage, and growth curve assay to evaluate the biological features of HPLF. RESULTS: The success rate of primary culture of HPLF was 77.8%. Cultured cells were spindle-shaped, and had a positive reaction to antibodies against vimentin, and a negative reaction to antibodies against keratin. Their morphological and biological characteristics were similar to those of typical HPLF. Growth of HPLF obtained by this method was satisfactory. CONCLUSION: The success rate of primary culture of HPLF is significantly increased by explants combined with enzymatic digestion. The method is simple and feasible.