| 1279 Bone Density Around Endosseous Implants Determined by Quantitative Computed Tomography | ||
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G. GRIFFITHS, Veterans Administration Medical Center, Baylor College of Dentistry, Dallas, TX, USA Objectives: The purpose of this pilot study is to non-invasively determine bone mineral density (BMD) around endosseous implants using 3-D medical reconstruction software (Vitrea2™) and quantitative computed tomography. Methods: Edentulous male patients (n=7, age 61.5±11.5 years) were selected for implant evaluation and placement. Two-stage implant (Zimmer™) placement procedures were utilized. Patients requiring 2-4 implants were initially seen for placement of half the total number of implants unilaterally. Baseline CT scan (Siemens Sensation™ CT/I Cardiac Scanner) was then performed on each patient. 6 months from baseline, the remaining contralateral implant(s) were placed, and subsequent CT scan performed for analysis. Total dose exposure for each CT scan limited to 1-2 mSv by narrowing region of interest (ROI). CT axial scans (1mm-slice width) were performed to evaluate bone characteristics including BMD, 3-D topography, and dimensional measurements for implant placement. Hounsfield units (HU) were measured at implant placement sites and non-operated sites in maxilla/mandible and calibrated using epoxy-resin gradient phantom (CIRS) placed against patient's face during scanning. Hounsfield units were assigned by software to each gradient component of the phantom, allowing conversion of HU to BMD measurement as mg mineral/mL. DICOM data from Vitrea2 was converted to 8-bit/256 gray-scale images and analyzed using ImageJ v.1.35i for macroscopic bone changes. Total #CT slices analyzed=182 for 14 implants. Results: BMD ranged from 1,247±472mg/mL in mandible and 570±205mg/mL in maxilla, depending on ROI and topography surrounding implant. Conclusions:This novel approach to bone density analysis is being used in an ongoing investigation to determine effect of an oral bisphosphonate, alendronate (Fosamax®), on implant osseointegration in patients. This technique has significant potential in screening cancer patients with osteolytic metastatic disease taking intravenous or oral bisphosphonates, who might develop osteonecrosis of the jaws (ONJ). Supported by Veterans Administration Grant #04-069/Merck US-IISP Grant #29268. | ||
| Seq #109 - Diagnostics & Drugs 3:30 PM-4:30 PM, Thursday, 29 June 2006 Brisbane Convention & Exhibition Centre Exhibit Hall 1 | ||
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