Cone-beam computed tomographic characteristics in degenerative temporomandibular joint disease patients with chewing side preference.

OBJECTIVES: This study is aimed at assessing the Cone-beam computed tomographic (CBCT) characteristics of temporomandibular joints (TMJ) in degenerative temporomandibular joint disease (DJD) patients with chewing side preference (CSP). MATERIALS AND METHODS: CBCT images of 98 patients with DJD (67 with CSP and 31 without CSP) and 22 asymptomatic participants without DJD were measured retrospectively to compare the osteoarthritic changes and the morphology of TMJ. Quantitative analysis of the TMJ radiographic images was performed to present a comparison between the three inter-group groups and between the two sides of the joints. RESULTS: The frequencies of the articular flattening and surface erosion occur more often in the preferred side joints of DJD patients with CSP than the contralateral side. In addition, the horizontal angle of condyle, the depth of glenoid fossa (DGF), and the inclination of articular eminence (IAE) were larger in DJD patients with CSP than that in asymptomatic participants (p<0.05). Also, the condylar anteroposterior dimension of preferred side joints was significantly less than that of non-preferred side (p=0.026), while the width of condyles (p=0.041) and IAE (p=0.045) was greater. CONCLUSIONS: DJD patients with CSP appear to have a higher prevalence of osteoarthritic changes, with the morphological changes such as flat condyle, deep glenoid fossa, and steep articular eminence, which might be considered the characteristic imaging features. CLINICAL RELEVANCE: This study found that CSP is a predisposing factor for the development of DJD, and attention should be paid to the existence of CSP in DJD patients during the clinical practice.

A comparative study of condyle position in temporomandibular disorder patients with chewing side preference using cone-beam computed tomography.

BACKGROUND: Chewing side preference (CSP) could cause structural and morphological changes of temporomandibular joint (TMJ) and has been suggested as one aetiology of temporomandibular disorders (TMDs), but the condylar position in TMD patients with CSP is unknown. OBJECTIVE: To compare the condylar position in the TMD patients with and without CSP. METHODS: Ninety TMD patients with unilateral symptom (69 with CSP and 21 without CSP) and 20 asymptomatic participants received cone-beam computed tomography. The condylar position was determined based on the measurements of sagittal joint spaces. Intergroup and intra-group comparisons of the condylar position were performed. RESULTS: The condyles in asymptomatic participants located nearly randomly in anterior, centric and posterior positions. Patients without CSP had significantly more posterior condyles than asymptomatic participants (57.1% vs 30.0%, p < 0.05). In patients with CSP, 50.7% of the condyles on the preferred chewing side and 42.0% on the unpreferred side located posteriorly, reaching no significant level compared with the asymptomatic participants and patients without CSP (p > 0.05). The symptomatic joints and asymptomatic joints in patients with CSP and without CSP showed no significant differences in condylar position. While patients without CSP had significantly more posterior condyles in symptomatic joints than asymptomatic participants (p < 0.05), patients with CSP showed a trend towards more posterior condyles in symptomatic joints compared with the asymptomatic participants (53.6% vs 30.0%, p = 0.054). CONCLUSION: Condylar position is not a strong indicator to differentiate CSP-related TMDs from non-CSP-related TMDs. Posterior condyle could not be viewed as one indicator of TMD.

The use of 3D-printed titanium mesh tray in treating complex comminuted mandibular fractures: A case report.

RATIONALE: Precise bony reduction and reconstruction of optimal contour in treating comminuted mandibular fractures is very difficult using traditional techniques and devices. The aim of this report is to introduce our experiences in using virtual surgery and three-dimensional (3D) printing technique in treating this clinical challenge. PATIENT CONCERNS: A 26-year-old man presented with severe trauma in the maxillofacial area due to fall from height. DIAGNOSIS: Computed tomography images revealed middle face fractures and comminuted mandibular fracture including bilateral condyles. INTERVENTIONS AND OUTCOMES: The computed tomography data was used to construct the 3D cranio-maxillofacial models; then the displaced bone fragments were virtually reduced. On the basis of the finalized model, a customized titanium mesh tray was designed and fabricated using selective laser melting technology. During the surgery, a submandibular approach was adopted to repair the mandibular fracture. The reduction and fixation were performed according to preoperative plan, the bone defects in the mental area were reconstructed with iliac bone graft. The 3D-printed mesh tray served as an intraoperative template and carrier of bone graft. The healing process was uneventful, and the patient was satisfied with the mandible contour. LESSONS: Virtual surgical planning combined with 3D printing technology enables surgeon to visualize the reduction process preoperatively and guide intraoperative reduction, making the reduction less time consuming and more precise. 3D-printed titanium mesh tray can provide more satisfactory esthetic outcomes in treating complex comminuted mandibular fractures.

Enhancement of periodontal tissue regeneration by transplantation of osteoprotegerin-engineered periodontal ligament stem cells.

INTRODUCTION: The objective of the present study was to evaluate the capacity of a tissue-engineered complex of human osteoprotegerin (hOPG)-transfected periodontal ligament stem cells (PDLSCs) seeding on beta-tricalcium phosphate (ß-TCP) to regenerate alveolar bone defects in New Zealand rabbits. METHODS: PDLSCs were isolated from rabbit periodontal ligament tissues and expanded in vitro to enrich PDLSC numbers, and their proliferative activities and differentiation capability were evaluated under specific induction conditions. Lentiviral vector containing hOPG and enhanced green fluorescent protein (EGFP) was constructed by using Gateway technology and transfected into rabbit PDLSCs. The expression of hOPG was determined with quantitative real-time reverse transcription-polymerase chain reaction and Western blot. The PDLSCs with or without engineered hOPG were seeded on ß-TCP scaffolds prior to transplantation. Morphological characterization of cells and materials was done by scanning electron microscope. Twenty rabbits with alveolar bone defects were randomly allocated into four groups and transplanted with ß-TCP, PDLSCs/ß-TCP, and hOPG-transfected PDLSCs/ß-TCP or were left untreated as a control. Animals were sacrificed 12 weeks after operation for histological observation and histomorphometric analysis. RESULTS: PDLSCs expressed STRO-1 and vementin and favored osteogenesis and adipogenesis in conditioned media. Expressions of hOPG were significantly upregulated after transfection of the lentiviral vector into PDLSCs. PDLSCs attached and spread well on ß-TCP, and there was no significant difference in growth of PDLSCs on ß-TCP between the hOPG transfection group and the non-transfection group. The histological observation and histomorphometric analysis showed that the hOPG-transfected PDLSCs/ß-TCP complex exhibited an earlier mineralization and more bone formation inside the scaffold than control, ß-TCP, and PDLSCs/ß-TCP complexes. Implantation of hOPG-transfected PDLSCs contributed to new bone formation as determined by EGFP gene expression under circularly polarized light microscopy. CONCLUSIONS: The present study demonstrated the feasibility of ß-TCP scaffolds for primary PDLSC culture and expression of hOPG gene in vitro and in vivo, and hOPG-transfected PDLSCs could serve as a potential cell source for periodontal bone regeneration, which may shed light on the potential of systemic hOPG gene therapy in combination with PDLSC tissue engineering as a good candidate in periodontal tissue engineering for alveolar bone regeneration.

[Effect of glimepiride on the glucose uptake of rat mandibular osteoblasts in hyperglycemia].

OBJECTIVE: To explore the effect of glimepiride on the glucose uptake as well as glucose transporter (GLUT)-1 and GLUT-3 expression levels of rat mandibular osteoblasts in hyperglycemia. METHODS: Primary osteoblasts were isolated and cultured. Then, the cells were placed in an osteogenic medium containing two glucose concentrations (5.5 and 16.5 mmol X L(-1)), with or without glimepiride (10 micromol x L(-1)). Glucose uptake was determined by employing 18F-deoxyglucose (18F-FDG) in the cells, and GLUT-1 and GLUT-3 expression levels were evaluated by Western blot analysis. RESULTS: Glucose at 16.5 mmol x L(-1) significantly inhibited 18F-FDG uptake and downregulated GLUT-3 protein expression in osteoblasts. Hyperglycemia increased GLUT-1 protein expression. Glimepiride significantly increased glucose uptake and upregulated GLUT-1 and GLUT-3. CONCLUSION: Glimepiride enhance the glucose transporter in rat osteoblasts at two different glucose concentrations.

[Temporomandibular joint ankylosis caused by systemic (distal) infection: a case report and literature review].

There were many causes for temporomandibular joint (TMJ) ankylosis including infection, trauma, degenerative changes and space-occupying lesion. This article reported a case of bilateral TMJ ankylosis caused by systemic (distal) infection. A 35-year old female patient complained of difficulty of opening mouth for about 20 years. She developed abscess in several places all over the body including bilateral TMJ 20 years ago. CT indicated that the condylar process was fused with the temporal bone. The patient was treated with resection of bilateral condylar/coracoid process and total joint prosthesis replacement. The maximal incisal opening was 2.5 cm 3 months post operation. The patient obtained a satisfied function of eating and speaking.

[Effects of glimepiride on proliferation, differentiation and mineralization of rat mandibular osteoblasts in hyperglycemia].

PURPOSE: To evaluate the effects of hyperglycemia and glimepiride on proliferation, differentiation and mineralization of rat mandibular osteoblasts to verify the hypothesis of dental implant administration. METHODS: Primary osteoblasts were isolated and cultured. Then the cells were placed in an osteogenic medium, containing 2 different concentrations of glucose (5.5 mmol/L and 16.5 mmol/L), with or without glimepiride (10 µmol/L). Cell proliferation was evaluated through MTT assay. Alkaline phosphatase (ALP) activity was determined by biochemistric method. Col I protein levels were determined by Western blot. OCN mRNA levels were tested by RT-PCR. SPSS 13.0 software package was used for statistical analysis. RESULTS: Hyperglycemic conditions interfered with the proliferation, ALP activity and OCN mRNA expression of rat osteoblasts, but improved the expression of Col I on day 14. Glimepiride stimulated rat osteoblast proliferation, ALP activity and OCN mRNA expression. The addition of glimepiride to normoglycemic (5.5 mmol/L) cultures registered a significant increase of Col I expression at 7 d and 14 d. Glimepiride significantly increased Col I expression in cells cultured with 16.5 mmol/L glucose for 7 days, but failed to increase at 14 d. CONCLUSIONS: Hyperglycemic conditions interfered with the proliferation, differentiation and mineralization of osteoblasts in rats; however, glimepiride improved the proliferation, differentiation and mineralization of osteoblasts in rats.

Extrapancreatic roles of glimepiride on osteoblasts from rat manibular bone in vitro: Regulation of cytodifferentiation through PI3-kinases/Akt signalling pathway.

Glimepiride, a third-generation sulfonylurea, has also been reported to have extrapancreatic functions including activation of PI3-kinase (PI3K) and Akt in rat adipocytes, skeletal muscle and endothelial cells. It is tempting to speculate that glimepiride would improve bone-implant contact in diabetic patients by mediating the activity of GLUT1 and 3 via the PI3K/Akt pathway. In this study, we investigated the effects of glimepiride on rat mandible osteoblasts cultured under two different levels of glucose. Cell proliferation was determined by the MTT assay. The supernatant was used to measure alkaline phosphatase (ALP) activity. Glucose uptake was determined by measuring the rate of 2-deoxy-d-glucose (2-DG) uptake. Western blotting was performed used to determine collagen I and PI3K/Akt expression. RT-PCR was performed used to determine osteocalcin (OCN) mRNA expression. We found that hyperglycemia down-regulated proliferation, ALP activity, OCN mRNA and GLUT3 protein expression in rat osteoblasts, and upregulated collagen I and GLUT1 protein expressions. Glimepiride enhanced the proliferation, ALP activity and OCN mRNA levels, and upregulated collagen I and GLUT1 and 3 protein expressions of rat osteoblasts at two different glucose concentrations. This study also provides the first evidence that glimepiride stimulates the phosphorylation of PI3K/Akt in osteoblasts and ameliorated the damage caused by high concentrations of glucose through the PI3K/Akt pathway.