The study of bone density assessment on dental implant sites

INTRODUCTION: Bone density is one of the important factors for the long term success of endosseous implants. The bone density varies from site to site and from patient to patient. A preoperative evaluation of the bone density is quite useful to oral surgeons for planning dental implantation. More accurate information on the bone density will help surgeons identify suitable implant sites, thereby increase the success rate of dental implantation. This study examined the correlation between the bone density measured preoperatively by computed tomography (CT) and the implant primary stability measured by resonance frequency analysis. Furthermore, the effects of the implant sites, gender, age and generalized systemic disorder patients on the bone density and primary implant stability were examined. MATERIALS AND METHODS: One hundred and fourteen patients were selected. None of the patients had undergone a tooth extraction or bone graft history in the previous year. Preoperatively, the patients underwent CT scanning to evaluate the Hounsfield unit (HU), and resonance frequency analysis (RFA) was used to evaluate the implant primary stability at the time of implant installation. All implants were 4.0 mm diameter and 11.5 mm length US II. All patients were recorded and the HU and implant stability quotient (ISQ) value were evaluated according to the sites, gender and age. RESULTS: The highest HU values were found in the mandibular anterior site (827.6+/-151.4), followed by the mandibular molar site (797+/-135.1), mandibular premolar site (753.8+/-171.2), maxillary anterior site (726.3+/-154.4), maxillary premolar site (656.7+/-173.8) and maxillary molar site (621.5+/-164.9). The ISQ value was the highest in the mandibular premolar site (81.5+/-2.4) followed by the mandibular molar site (80.0+/-5.7), maxillary anterior site (77.4+/-4.1), mandibular anterior site (76.4+/-11.9), maxillary premolar site (74.2+/-14.3) and maxillary molar site (73.7+/-7.4). The mean HU and ISQ value were similar in females and males. (HU: P=0.331, ISQ: P=0.595) No significant difference was also found in the age group respectively. However, the correlation coefficients between the variables showed a closed correlation between the HU and ISQ value. CONCLUSION: These results showed close correlation between the bone density (HU) and primary stability value (ISQ) at the time of implant installation (Correlation coefficients=0.497, P<0.01). These results strengthen the hypothesis that it might be possible to predict and quantify the initial implant stability and bone density from a presurgical CT diagnosis. These results strengthen the hypothesis that it might be possible to predict and quantify the initial implant stability and bone density from a presurgical CT diagnosis.

Multicentric melanotic neuroectodermal tumor of infancy: a case report

A melanotic neuroectodermal tumor of infancy (MNTI) is a uncommon osteolytic pigmented neoplasm that primarily affects the jaws of newborn infants. Most patients (> 90%) present with the tumor in the first year of life. Approximately 65% form in the maxilla, 11% in the mandible, 5% in the brain and elsewhere. MNTI is normally benign, but up to 15% may recur and a few have metastasized. Approximately 200 cases of MNTI have been reported but only 2 of them presented as multifocal. A case of MNTI in a 7 month old boy was encountered. The chief complaint was maxillary anterior ridge swelling. The incisional biopsy findings were MNTI. Two months after the first operation, mild swelling of another site was observed. The infant was examined periodically since undergoing two procedures with no recurrence. This case demonstrates the possibility of a multicentric MNTI. We report a multicentric MNTI with a review of the relevant literature.

The study of stability of absorbable internal fixation after mandibular bilateral sagittal split ramal osteotomy

INTRODUCTION: To evaluate the skeletal stability after a bilateral sagittal split osteotomy (BSSO) setback of the mandible fixed with a biodegradable internal fixation device or metal internal fixation device. MATERIALS AND METHODS: Thirty consecutive patients underwent mandibular setback via BSSO. Fifteen patients were fixed with a biodegradable internal fixation device or metal internal fixation device respectively. Posteroanterior (PA) and lateral cephalograms were taken preoperatively and at two days, 5.5 months and 14.5 months postoperatively. The relevant skeletal points were traced and digitized to evaluate the skeletal changes postoperatively. The relapse rates were analyzed and compared statistically. RESULTS: There was no statistically significant differences in postoperative stability between the two groups.(P<0.05) CONCLUSION: The biodegradable internal fixation device may make an effective device alternative to a metal internal fixation device for setback BSSO.

Primary Extranodal Marginal Zone B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue In The Oral Cavity : A Case Report