Characterization of short root anomaly in a Mexican cohort--hereditary idiopathic root malformation

The purpose of this study was to systematically characterize individuals with short root anomaly (SRA) without any history of orthodontic treatment. The long-term objective of the study was to improve diagnosis and treatment planning and determine risk factors for developing SRA.

Twenty-seven patients including two families and 16 unrelated individuals from (9-48 years) reported to orthodontic and/or dental practitioners within the USA.

Digital panoramic and periapical films were analyzed to document pattern and frequency of SRA-affected teeth. Crown-to-root (CR) ratios of the affected teeth were used to characterize the extent of malformation. Pedigree analysis by inspection was completed for one family to determine pattern of inheritance.

Twenty-six of the twenty-seven individuals were of Latino descent, and one was of Filipino descent. Hard tissues including enamel, dentin, pulp chambers and canals, and surrounding soft tissues were normal. We found that 25 of 27 individuals had localized SRA and two Latino individuals had generalized SRA. Teeth were affected bilaterally with maxillary central incisors (~63%) and mandibular second premolars most commonly involved (~33%). Affected teeth had a distinct, similar radiographic appearance; in the generalized cases, there was a more severe affection with larger (~twice) CR ratios. Ninety-four percent of affected individuals did not show a significant difference in the CR ratios at different ages. Pedigree analysis suggests an autosomal dominant inheritance pattern in one family.

This is the first report to show that SRA occurs more frequently in Latino individuals and has a predilection for anterior teeth. The occurrence of SRA in two families further confirms a hereditary component and supports a distinct nosology and nomenclature, hereditary idiopathic root malformation (HIRM) and warrants further investigation.