Tooth Eruption and Dental Impaction

Abstract

A broad range of variation exists in the normal eruption times for primary and permanent teeth in humans. However, normality is usually associated with bilateral symmetry. Furthermore, cases where eruption time is grossly beyond the extremes of normalcy might be considered to represent a pathological state [1]. Radiography plays an important part in determining the normality of tooth eruption with regard to position and time sequence. This is particularly important in patients whose teeth are undetectable by clinical means, such as those with delayed eruption or impaction. Impaction is the impedance of dental eruption by adjacent or overlying tooth, bone, or pathosis.

Occasionally, one or two primary teeth—natal teeth— are present at birth or, in the case of neonatal teeth, erupt within the first month of life [2]. Eighty-five percent of such prematurely erupting teeth are mandibular primary central incisors, 11% are primary maxillary incisors, and 4% are primary posterior teeth [2]. Such teeth are generally well-formed and normal in all respects.