Efficacy of Cone Beam Computed Tomography in Diagnosing Osteoporosis

Osteoporosis is a major health problem worldwide characterized by reduced bone mass and disrupted bone architecture that leads to increased susceptibility to fractures. It has become one of the leading causes of morbidity and mortality in older males and females, occurring more commonly in post-menopausal women.1 The prevalence of osteoporosis varies from 16% to 30% in Caucasian women with 39.7% women risked at sustaining a fracture once in a lifetime.1In a study conducted upon middle aged Indian women, a high prevalence of osteopenia (52%) and osteoporosis (29%) was found, with nutritional deficiency being the causative factor. 2 With such high prevalence rates, the need for timely detection cannot be overemphasized. The disease being largely asymptomatic, comes under the radar of the clinician only when a fracture occurs. The diagnosis is largely centered around measurement of bone mineral density by use of Single and dual X-ray absorptiometry (DXA), Ultrasonic measurement of bone, Computed tomography and Radiography with DXA being the gold standard and also the most commonly used technique.3 Dental radiographs are usually advised for a variety of dental diseases and conditions. This provides an opportunity to use dental radiographs as a screening tool for predicting osteoporosis. The role of pantomographs as a screening tool is well established.8,9 Cone beam computed tomography (CBCT), since its advent in 1999, has been specialised for dental use with its various advantages over conventional CT such as lower exposure dose, higher spatial resolution and space saving. Nowadays, CBCT is the modality of choice for patients requiring implant planning.it provides high resolution images in all three planes thereby allowing accurate quantitative measurements of hard structure. Over the recent years, many clinicians have attempted to establish CBCT as a modality to evaluate bone mineral content(BMC) and have concluded that lumbar vertebrae and femoral neck osteoporosis can be predicted accurately from the radiodensity values of the body of the mandible and it is possible to evaluate BMC from the voxel values of CBCT for dental implant treatment5,6.

However, there is still a controversy regarding use of CBCT for determination of bone quality. CBCT gray values give an approximate density and therefore cannot be expressed as HU as in conventional CT.

Few researchers have explored the use of radio morphometric indices such as computed tomography mandibular index superior (CTI(S)), computed tomography mandibular index inferior (CTI(I)), computed tomography cortical index (CTCI) and the computed tomography mental index (CTMI: inferior cortical width) and have been instrumental in establishing the fact that these indices can be used to differentiate between osteoporotic and non-osteoporotic patients7. Very few studies have been done using CBCT and no such study is available in the literature on an Indian population. Thus, this study will aim at determining the utility of these CBCT indices in detection of osteoporosis (confirmed through DXA scan) to aid in timely detection and therefore timely intervention to increase the quality of life and reduce morbidity and mortality occurring as a consequence of this disease.