Dental Outcomes of Preterm Infants

Diane L. Eastman, MA, RN, CPNP


NAINR. 2003;3(3) 

In This Article

Delayed Eruption and Size of Teeth

The timing of primary teeth eruption in premature infants has not been well established. Delayed eruption has been observed in several longitudinal and cross-sectional studies.[29,30,31] In each of these studies, the delay in tooth eruption was related to gestational age or low birth weight.

Viscardi et al[32] attempted to relate delayed tooth eruption to neonatal factors other than birth weight and gestational age. They followed a group of 35 infants with birth weights less than 2,500 grams and gestational age less than or equal to 36 weeks. Fourteen (40%) of this group had their first tooth erupt in the "normal" range of less than or equal to 10 months chronological age, and 21 (60%) had the first tooth erupt over 10 months of age. The late erupting group was comprised of those with birth weights <1,000 grams and/or <31 weeks' gestation. Other factors appeared to be important related to nutrition. The nutritional factors that correlated significantly with tooth eruption were age when full enteral feedings were achieved, age when oral vitamin supplements were started, and average weight gain per day. They concluded that prolonged intubation for illness and inadequate nutrition were important factors affecting the timing of tooth eruption.

Backström et al[33] studied the development of primary and permanent teeth in a group of preterm infants and also examined calcium, phosphorus, and vitamin D supplementation. Birth weights in the preterm group ranged from 690 to 1,930 grams and gestational ages ranged from 23 to 35 weeks. The children were followed until they reached the ages of 9 to 11 years. A control group was recruited for comparison. The corrected teething age was similar in both groups as a whole. When divided by sex, the preterm girls had significantly later tooth eruption than full-term girls. This difference was not observed between preterm and full-term boys. Preterm girls also had significantly later tooth eruption than preterm boys. Full-term boys and girls showed no differences. By 2 years of age, the median number of teeth was the same in both groups with no difference noted between the genders. The heavier the infant at 3 months chronological age, the sooner the first tooth erupted. Early vitamin D supplementation did not affect maturation of primary teeth. Permanent teeth maturation did not differ between the preterm and control groups. There was no difference between the sexes, and maturation of permanent teeth did not depend on body weight. If maturation and teething of the primary teeth was delayed at 1 year of age, it was also delayed in the permanent teeth at 9 to 11 years. The most mature permanent teeth were found in the preterm children who received vitamin D at a dose of 1,000 international units (IU)/d; however, mineral supplementation did not affect maturation.

Harila-Kaera et al[1] studied the effect of preterm birth on permanent tooth crown dimensions. Three hundred twenty-eight premature black and white children and 1,804 control children were examined at 6 to 12 years of age. This study suggested decreased tooth crown dimensions in some preterm infants. One significant difference was increased crown dimensions of some permanent teeth in the white preterm boys and black preterm girls and smaller dimensions in the white girls and black boys. Differences between gender, race, and growth patterns, especially accelerated or catch-up growth, may influence the determination of permanent tooth crown dimensions.


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