Unilateral primary or secondary retention of permanent teeth, and dental malformations.

The purpose of the present investigation was to describe the dentition in subjects with local primary or secondary unilateral retention of two or more permanent teeth, and to elucidate the aetiology by comparing the regions of retention with the innervation pattern of the jaws. The material comprised radiographic dental orthopantomograms (OTP) from 12 patients with an age range of 6-18 years (six females and six males). The locations of retention and the dental morphology in the affected regions were analysed. Comparison with contralateral teeth was undertaken and the innervation pattern of the affected field was considered. Varying degrees of dental root malformation were found to be associated with primary and secondary retention. More pronounced root malformations were observed in subjects with several affected teeth. A connection between unilateral retained permanent teeth and temporary or permanent disruption of the nerve supply to the affected region is suggested.