A Nonsurgical Treatment Strategy for Longstanding, Nonreducible, Bilateral Temporomandibular Joint Dislocation: A Case Report.

Temporomandibular joint (TMJ) dislocation is a condition in which the mandibular condyle is displaced from the glenoid fossa and must be manipulated to return it to its normal position. Among several diagnostic subtypes, long-standing or chronically protracted TMJ dislocation is rare and challenging to manage. Treatment options include various nonsurgical and surgical approaches. This case report describes the successful nonsurgical management of a longstanding bilateral TMJ dislocation using elastic traction with a removable appliance and posterior bite planes. This technique should be attempted before performing additional surgical interventions.

Intermittent compressive force induces human mandibular-derived osteoblast differentiation via WNT/ß-catenin signaling.

Mechanical force induces an efflux of ATP that regulates osteoblast differentiation. However, the effect of mechanical force-induced ATP efflux on WNT/ß-catenin signaling remains unclarified. The aim of this study was to investigate the effect of intermittent compressive force (ICF) and ICF-induced extracellular ATP on osteoblast differentiation via WNT/ß-catenin signaling in human mandibular-derived osteoblast precursors (hMOBPs). The hMOBPs were subjected to ICF (1.5 g/cm2 , 0.3 Hz) for 20 h. To investigate the role of ATP, Apyrase (0.5 units/mL), an enzyme that hydrolyzes ATP, was added 30 min before ICF was applied. The extracellular ATP levels were measured immediately after ICF was removed. The mRNA expression of osteogenic related genes, including WNT was evaluated via quantitative real time polymerase chain reaction. In vitro mineralization was determined by Alizarin Red S staining. The localization of ß-catenin was detected using immunofluorescence staining and lentiviral-TOP-dGFP reporter assay. The results demonstrated that ICF increased ATP efflux and in vitro mineralization by hMOBPs. In addition, OSX, ALP, and WNT3A mRNA expression and ß-catenin nuclear translocation increased when ICF was applied. The upregulation of these genes was reduced by Apyrase, suggesting the role of ICF-induced ATP on osteoblast differentiation. Notably, ICF altered the mRNA expression of purinergic 2X receptors (P2XRs). A P2X1R antagonist (NF449) downregulated ICF-induced WNT3A, OSX, and ALP mRNA expression. Moreover, when 25 µM α, ß-meATP, a P2X1R agonist, was added, WNT3A, and OSX expression increased. In conclusion, our results demonstrate that ICF-induced ATP enhanced hMOBP differentiation. This enhancement was associated with WNT/ß-catenin signaling and P2X1R activation.

Purinergic 2X7 receptor activation regulates WNT signaling in human mandibular-derived osteoblasts.

OBJECTIVE: Purinergic 2X7 receptor (P2X7R) activation modulates in vitro mineralization by primary rat and human osteoblasts. However, the detailed mechanism of how P2X7R activation affects primary human osteoblasts remains unclear. The aim of this study was to investigate the effect of P2X7R activation on human mandibular-derived osteoblast (hMOB) differentiation. DESIGN: Primary human osteoblasts were obtained from non-pathologic mandibular bone from healthy patients. The hMOBs were cultured in osteogenic medium with or without 0.5-5µM 2'(3')-O-(4-benzoyl) benzoyl-ATP (BzATP), a selective P2X7R agonist. The mRNA expression of osteogenic differentiation markers and WNT-signaling molecules was investigated by quantitative real time polymerase chain reaction. In vitro mineral deposition was determined by Alizarin Red S staining. Transfection of small interfering RNA was performed to confirm the effect of P2X7R activation. WNT/ß-catenin signaling was detected by immunofluorescence staining for ß-catenin. RESULTS: BzATP inhibited osteogenic medium-induced RUNX2 and OSX mRNA expression in hMOBs. Moreover, BzATP significantly retarded in vitro mineralization. These findings indicated that BzATP/P2X7R activation inhibited hMOB differentiation. Interestingly, reduced WNT3A mRNA expression and blockage of osteogenic medium-induced ß-catenin nuclear translocation were also found. These data suggested that WNT signaling might be a target of P2X7R-regulated osteogenic differentiation. Furthermore, when recombinant human WNT3A was added to the BzATP-treated group, it rescued the reduced RUNX2 and OSX expression, and in vitro mineralization. CONCLUSION: Our results demonstrate that P2X7R activation by BzATP inhibits hMOB differentiation. This inhibitory effect was associated with inhibition of the WNT/ß-catenin signaling pathway.

Notch signalling inhibits the adipogenic differentiation of single-cell-derived mesenchymal stem cell clones isolated from human adipose tissue.

ADSCs (adipose-derived mesenchymal stem cells) are candidate adult stem cells for regenerative medicine. Notch signalling participates in the differentiation of a heterogeneous ADSC population. We have isolated, human adipose tissue-derived single-cell clones using a cloning ring technique and characterized for their stem cell characteristics. The role of Notch signalling in the differentiation capacity of these adipose-derived single-cell-clones has also been investigated. All 14 clones expressed embryonic and mesenchymal stem cell marker genes. These clones could differentiate into both osteogenic and adipogenic lineages. However, the differentiation potential of each clone was different. Low adipogenic clones had significantly higher mRNA expression levels of Notch 2, 3 and 4, Jagged1, as well as Delta1, compared with those of high adipogenic clones. In contrast, no changes in expression of Notch signalling component mRNA between low and high osteogenic clones was found. Notch receptor mRNA expression decreased with the adipogenic differentiation of both low and high adipogenic clones. The γ-secretase inhibitor, DAPT (N-[N-(3,5-difluorophenacetyl)-l-alanyl]-(S)-phenylglycine t-butyl ester), enhanced adipogenic differentiation. Correspondingly, cells seeded on a Notch ligand (Jagged1) bound surface showed lower intracellular lipid accumulation. These results were noted in both low and high adipogenic clones, indicating that Notch signalling inhibited the adipogenic differentiation of adipose ADSC clones, and could be used to identify an adipogenic susceptible subpopulation for soft-tissue augmentation application.

Antibiotic prophylaxis for orthognathic surgery: a prospective, comparative, randomized study between amoxicillin-clavulanic acid and penicillin.

OBJECTIVE: The present study was designed to evaluate the prophylactic efficacy after the correction of dentofacial deformities between short- and long-term penicillin and amoxicillin-clavulanic acid. MATERIAL AND METHOD: The present study was prospective, randomized, and double blinded. Patients were separated into four groups randomly: short-term and long-term (5 days) penicillin and short-term and long-term (5 days) amoxicillin-clavulanic acid. RESULTS: One hundred twenty two patients were assigned randomly into the four groups. Infection developed in a patient in the short-term amoxicillin-clavulanic acid group and in a patient in the long-term penicillin group. CONCLUSION: There were no differences in infection between the two groups of antibiotics. Based on the present study, short-term penicillin is still the most appropriate choice for prophylactic antibiotic in orthognathic surgery.

A review of odontogenic keratocysts and the behavior of recurrences.

OBJECTIVE: The purpose of this study is to report experiences of odontogenic keratocysts (OKCs) and analyze information regarding recurrences to better understand the nature of recurrences. STUDY DESIGN: Fifty-one cases of OKC treated at the Faculty of Dentistry, Chulalongkorn University, from 1988 to 2003 were studied retrospectively. Clinicoradiographic features, histologic features, and methods of treatment were reviewed. Recurrences were analyzed and compared with respect to sites of involvement, relationship to the remaining teeth, and methods of treatment. RESULTS: OKCs occurred predominantly in the 11- to 40-year-old age group. The body-angle-ramus area of mandible was the most common site of occurrence. Radiographically, the unilocular to multilocular radiolucency ratio was 2.5:1. Multilocular lesions occurred more frequently in the mandible (P < .05). Most of the lesions were diagnosed histologically as parakeratinized OKC (93.7%). The patients were followed from 1-14.6 years. However, 20 patients were lost to follow-up after a short period of time, and recurrences were found in 7 out of 31 cases (22.6%). The recurrent tumors occurred more frequently in patients who had an OKC associated with the remaining teeth and were treated by enucleation or enucleation with adjuvant therapy. CONCLUSIONS: According to a high recurrent rate of OKCs treated by enucleation, clinicians should give more attention to the dentate area if the enucleation is chosen as the treatment of choice.

Biologic mechanical advantages of 3 different cranial bone grafting techniques for implant reconstruction of the atrophic maxilla.

PURPOSE: The purpose of this study was to test the mechanical capacities of 3 different bone grafting techniques in the atrophic maxilla when co-stabilized with dental implants. Reconstruction of the atrophic maxilla is a difficult clinical challenge and implants cannot be placed without adequate bone. METHODS: The biomechanical performance of 3 different grafting techniques was evaluated in vitro using a maxillary model, cadaveric cranial bone blocks, and dental implants. A maxillary model fabricated from polyurethane (sawbone) was selected as a substrate for this study because of consistency in shape, size, and mechanical properties. This anatomic model was more consistent than different cadaveric maxilla, where significant variation was found to exist among atrophic specimens. Cadaveric cranial bone graft blocks were secured to the model maxilla (sandwich, ridge only, and sinus inlay) with a dental implant. The strength of the implant/bone graft complex was tested to failure in an Instron machine (Instron Inc, Canton, MA). RESULTS: The 3 bone grafting methods showed significantly different deformation and strength characteristics. The sandwich technique enhanced resistance to deformation under higher imposed loads. The location of the graft influenced the overall mechanical performance (eg, the ridge onlay) and showed a significantly higher resistance to compressive loads applied toward the alveolar ridge (mastication force). CONCLUSION: The ridge onlay grafting procedures created a higher biomechanical tolerance to imposed load than the sinus grafting (sinus inlay). Sinus grafting, although successful, was not the most ideal location for immediate mechanical loading resistance when compared with ridge augmentation in this in vitro model.