Idiopathic external root resorption associated to hypercalciuria.

Although external root resorption (ERR) is a physiological process in deciduous dentition, it is very infrequent in permanent dentition - where the phenomenon is related to the existence of inadequate occlusal forces, periodontal pathology and microtraumatisms, etc. However, in many cases root resorption cannot be attributed to any concrete cause; such cases are defined as idiopathic external root resorption (IERR). Epidemiological studies have found that the underlying cause can only be established in 5% of all ERR. The present study describes three cases of IERR with different degrees of involvement and associated to mild calciuria and a history of nephrolithiasis. Hypercalciuria with normal blood calcium levels is usually idiopathic and exhibits a familial trait, with a prevalence of 20-40 cases per 1,000 individuals in adults. A form of hypercalciuria associated to nephrolithiasis with a mutation of the CLCN5 gene has been identified, involving low molecular weight proteinuria - though this mutation has not been uniformly demonstrated in most cases of idiopathic hypercalciuria. The peculiarity of the cases described in the present study is attributable to the coexistence of IERR with normocalcemic hypercalciuria and nephrolithiasis - thus pointing to the need for in-depth evaluation of the possible association of these three clinical situations.