The Effect of Preterm Birth on the Development of the Dentition

The aim of this study was to examine the effect of preterm birth on the development of the dentition. The spesific aims were to examine the effect on deciduous and permanent tooth crown dimensions, the eruption of permanent teeth and the sagittal occlusal relationships within the dentition. The subjects consisted of 328 prematurely born (< 37 gestational weeks ) white and black children and 1804 control children, who participated in the cross-sectional study of the Collaborative Perinatal Project (USA) in the 1960's and 1970's. Dental examinations, including dental casts were performed at the age of 6–12 years. Tooth crown size measurements, recording of the sagittal occlusal relationships and tooth eruption stages were performed by examining the dental casts. In general larger permanent tooth crown dimensions were found in preterm white boys and black girls and smaller permanent tooth crown dimensions in preterm white girls and black boys. There were both increased and decreased deciduous tooth crown dimensions in preterm children compared to controls, but no significant differences were found. Boys had larger tooth crown sizes than girls within all preterm and control groups showing sexual dimorphism. The results showed earlier eruption of permanent incisors and first molars in all preterm children compared to controls and also according to sex and race. Concerning the sagittal occlusal relationships, the results showed greater prevalence of prenormal canine relationships in preterm group than in the controls. When the molar relationships were concerned, the prevalence of mesial molar occlusion was greater in the preterm group. The incidence of bilateral symmetrical canine relationship was the same in both preterm and control groups, but inside the preterm group the girls had better symmetry than the boys. The findings of this research suggest that short gestation is not associated with reduced permanent and deciduous tooth crown dimensions in prematurely born children and also confirm the presence of the sexual dimorphism in tooth crown size. The studies also indicate that the clinical tooth eruption is accelerated in all observable permanent teeth in prematurely born children. The findings of occlusal morphology indicated that premature birth may effect the sagittal occlusal development. General health condition, neonatal and postnatal factors like intubation, postnatal molding of head shape and the importance of catch-up growth and early functional activity should be considered as possible influencing factors. Preterm birth may also interfere with the development of symmetry and lateralization.