Three-dimensional finite elemental analysis of zygomatic implants in craniofacial structures

The objective of this study was to analyse stress distribution in craniofacial structures around zygomatic osseointegrated implants. An integrated system for Digital Imaging and Communications in Medicine (DICOM) data were utilized to create a three-dimensional model of craniofacial structures. The amount and distribution of the main stresses were compared using three-dimensional finite elemental analysis. The system allowed visual confirmation and analysis of stress distribution as well as the convenient and simple construction of a digital biomechanical model that provided details of anatomical structures in the regions of interest. Zygomatic implants with or without connected implants supporting the superstructure were compared. Stresses in severely resorbed maxillae with connected implants were not concentrated around the alveolar bone supporting the zygomatic implants. Stresses where there were no connected implants tended to be generated in the zygomatic bone, at the middle part of the zygomatic implant and at the joint of the fixture-abutment. Stress due to occlusal forces is mainly supported by the zygomatic bone, is transferred predominantly through the infrazygomatic crest, and is divided between the frontal and temporal processes of the zygomatic bone in different directions.     

Short-term efficacy of physical therapy compared to splint therapy in treatment of arthrogenous TMD

A prospective randomized study was carried out to evaluate the efficacy of physical therapy in addition to splint therapy on treatment outcome in patients with temporomandibular disorders (TMD) with respect to objective and subjective parameters. Twenty-six patients suffering from an arthrogenic TMD and exhibiting a painfully restricted jaw opening were randomized in two groups. Thirteen patients were treated solely with Michigan splint (group I), 13 patients received supplementary physical therapy (group II). Before treatment a clinical examination and electronic recording of jaw movements were performed and subjective pain level was evaluated by visual analogue scales. After 3 months of therapy maintenance of improvement was evaluated. Within treatment groups comparison of data before and after treatment was analysed using Wilcoxon test. Groups were compared by Mann-Withney-U test. A P-value < 0.05 was considered significant. Compared with the baseline, in both groups mandibular movement capacity increased significantly after treatment, whereas subjective pain decreased significantly (P < 0.05). Active jaw opening increased from 28.6 +/- 5.8 to 35.9 +/- 4.8 mm in group I and from 30.1 +/- 5.4 to 40.8 +/- 4.1 mm in group II. After therapy the difference of active jaw opening between groups was significant (P < 0.05). Physical therapy also gave a supplementary improvement of protrusive mandibular movement capacity during electronic registration and subjective pain level. For none of these parameters this difference between groups was significant. Physical therapy seems to have a positive effect on treatment outcome of patients with TMD.     

Isolated osteochondroma near the mandibular angle

A benign tumour of osseous and cartilaginous origins, osteochondroma generally develops in osseous tissue and is frequently found near the end of long bones. It is relatively rare in the oral and maxillofacial region but is common in the mandibular condyle and coronoid process in the pediculate form. This is a report on a rare case of osteochondroma in soft tissue near the mandibular angle without pedicle to the bone.     

Genome-wide association scan for childhood caries implicates novel genes

Dental caries is the most common chronic disease in children and a major public health concern due to its increasing incidence, serious health and social co-morbidities, and socio-demographic disparities in disease burden. We performed the first genome-wide association scan for dental caries to identify associated genetic loci and nominate candidate genes affecting tooth decay in 1305 US children ages 3-12 yrs. Affection status was defined as 1 or more primary teeth with evidence of decay based on intra-oral examination. No associations met strict criteria for genome-wide significance (p < 10E-7); however, several loci (ACTN2, MTR, and EDARADD, MPPED2, and LPO) with plausible biological roles in dental caries exhibited suggestive evidence for association. Analyses stratified by home fluoride level yielded additional suggestive loci, including TFIP11 in the low-fluoride group, and EPHA7 and ZMPSTE24 in the sufficient-fluoride group. Suggestive loci were tested but not significantly replicated in an independent sample (N = 1695, ages 2-7 yrs) after adjustment for multiple comparisons. This study reinforces the complexity of dental caries, suggesting that numerous loci, mostly having small effects, are involved in cariogenesis. Verification/replication of suggestive loci may highlight biological mechanisms and/or pathways leading to a fuller understanding of the genetic risks for dental caries.     

Expression and possible immune-regulatory function of ghrelin in oral epithelium

Originally found in stomach mucosa, ghrelin is a peptide appetite hormone that has been implicated as an immuno-modulatory factor. Ghrelin has also been found in salivary glands and saliva; however, its expression patterns and biological properties in the oral cavity remain unclear. Therefore, we investigated the expression patterns of ghrelin in saliva, gingival crevicular fluid (GCF), and gingival tissue, as well as its in vitro effects on IL-8 production by TNF-α or LPS-stimulated oral epithelial cells. In the clinical samples obtained from 12 healthy volunteers, the concentration of ghrelin in GCF remarkably exceeded that detected in saliva. The expression of ghrelin mRNAs and growth hormone secretagogue (GHS) receptors could be detected in human oral epithelial cells. Immunohistochemical analysis revealed the expression of ghrelin in gingival epithelium, as well as in fibroblasts in the lamina propria. Ghrelin increased intracellular calcium mobilization and cAMP levels in oral epithelial cells, suggesting that ghrelin acts on epithelial cells to induce cell signaling. Furthermore, synthetic ghrelin inhibited the production of IL-8 from TNF-α or LPS-stimulated oral epithelial cells. These results indicate that ghrelin produced in the oral cavity appears to play a regulatory role in innate immune responses to inflammatory infection.     

Long-term results of treatment for temporomandibular disorders: an evaluation by patients

In this study, 110 patients with temporomandibular disorders who had been treated 2 to 81/2 years earlier were asked to evaluate the treatment they received. Of the patients, 85.5% reported that they were not experiencing pain or that they were experiencing much less pain; 79.1% reported that the treatment they had received had helped them completely or considerably. Analysis of the data did not disclose a subgroup or factor that could be correlated with the reduction of pain or the patient's perception of the success of treatment.     

Pattern of distribution of T lymphocytes, Langerhans cells and HLA-DR bearing cells in normal human oral mucosa

The tissue distribution of helper/inducer and suppressor/cytotoxic T cells, Langerhans cells (LC) and HLA-DR bearing cells was determined in normal oral mucosa by use of monoclonal antibodies OKT4, OKT8, OKT6 and OKIa1, respectively. OKT4+ and OKT8+ cells were invariably present in normal oral epithelium and in the lamina propria. OKT8+ cells were consistently seen inside the basal cell layer of the epithelium. The distribution of LC in oral epithelium showed regional variation. In palatal epithelium LC were evenly distributed in the basal half of the epithelium, whereas in buccal mucosa the highest concentration of LC was seen in the epithelium overlying the tips of connective tissue papillae. OKIa1 stained dendritic cells in the epithelium and plump cells with small dendritic processes in the connective tissue. Some of the latter were located close to the basal cells of the epithelium. The consistent relationship between immunocompetent cells and the epithelium of the oral mucosa suggests the presence of a local immunologic defence barrier in the oral mucosa.