Comparison of palatal and alveolar cysts of the newborn in premature and full-term infants.

PURPOSE The frequency of cysts has been reported to be high in newborns, but they are rarely seen after three months of age. There has been a lack of studies describing the clinical prevalence in the premature infant after 22 weeks and less than 37 weeks gestation. The purpose of this study was to quantify and describe the clinical prevalence of palatal and alveolar cysts in premature infants as compared to full term infants. METHODS Sixty premature infants, born at less than 37 weeks gestation, and 60 term infants, born greater than 37 weeks gestation, were examined in the first few days after birth for the presence of palatal and alveolar cysts. Alveolar cysts were further classified according to location as either maxillary or mandibular, and anterior or posterior. Information regarding birth weight, race, sex, and maternal health during pregnancy was also collected. RESULTS The prevalence of palatal cysts in the premature infant (9%) is less than the prevalence in term infants (30%), to a statistically significant level (P < 0.004, by the Fisher's exact test). Differences between preterm and term infants were also noted in the prevalence of maxillary anterior alveolar cysts, (preterm having 27% and term 58%, P < 0.0005) and maxillary posterior alveolar cysts (preterm 2% and term 10%, P < 0.06). The prevalence of palatal and maxillary alveolar cysts was demonstrated to increase with increasing gestational age, increasing postnatal age, and increasing birth weight (by plots of cumulative percent). No significant differences were found for gender or for race. CONCLUSION The prevalence of palatal and alveolar cysts in the premature infant is less than the prevalence in the full term infant to a statistically significant level. Palatal and maxillary alveolar cysts increase with increasing gestational age, post-natal age, and birth weight.