Primary Canine Hypoplasia in African American and Indonesian Children: Prevalence, Expression and Tooth Size

This study documents the prevalence and expression of localized hypoplasia of primary canine teeth (LHPC) in two groups: African American (Gullah) and Indonesian (Malay). New data for these groups clarify defect etiology. The impact of variation in tooth size on defect expression has not been studied in humans.

The author analyzed dental casts of Gullah (n = 112 individuals, 466 teeth) at Ohio State University and Javanese Malay (n = 141 individuals, 582 teeth) at Gadja Mada University for primary canine hypoplasia. Scoring of enamel defects, measures of defect size, and crown size were evaluated for accuracy. Measures of intra-observer reliability are high (Kappa = 0.83, %concordance = 94.5; n = 175 teeth).

As expected, the prevalence of LHPC in Gullah (12.7% of teeth, 33.9% of individuals) was significantly greater than in Malay (3.1% of teeth, 11.4% of individuals). The number of teeth affected per individual is often two or less. Gullah defects were common on the cervical 1/3 of the crown and on the mesial aspect of lower canines. Large defects (> 2.0 mm, height and width) are frequent in lower canines; smaller-sized lesions appear often in upper and lower canines. Differences in mean tooth size of individuals with and without defects vary by group and sex.

Inter-group differences reaffirm the impact of socio-economic factors in LHPC etiology. Defect location is preferentially cervical, implying post-natal stress, and mesial in lower canines. Malay tooth crown size is not a factor in defect etiology, yet Gullah females with LHPC have larger crown size.