Is premature birth an orthodontic risk factor? A controlled epidemiological clinical study

Intermittent hypoxia in neonatal rodents affects facial bone growth

Preterm human infants often show periodic breathing (PB) or apnea of prematurity (AOP), breathing patterns which are accompanied by intermittent hypoxia (IH). We examined cause-effect relationships between transient IH and reduced facial bone growth using a rat model. Neonatal pups from 14 timed pregnant Sprague-Dawley rats were randomly assigned to an IH condition, with oxygen altering between 10% and 21% every 4 min for 1 h immediately after birth, or to a litter-matched control group. The IH pups were compared with their age- and sex-matched control groups in body weight (WT), size of facial bones and nor-epinephrine (NE) levels in blood at 3, 4, and 5-weeks. Markedly increased activity of osteoclasts in sub-condylar regions of 3-week-old IH-treated animals appeared, as well as increased numbers of sympathetic nerve endings in the same region of tissue sections. Male IH-pups showed significantly higher levels of NE levels in sera at 3, 4 as well as 5-week-old time points. NE levels in 4- and-5-week-old female pups did not differ significantly. Intercondylar Width, Mandible Length and Intermolar Width measures consistently declined after IH insults in 3- and 4-week-old male as well as female animals. Three-week-old male IH-pups only showed a significantly reduced (p < 0.05) body weight compared to those of 3-week controls. However, female IH-pups were heavier than age-matched controls at all 3 time-points. Trabecular bone configuration, size of facial bones, and metabolism are disturbed after an IH challenge 1 h immediately after birth. The findings raise the possibility that IH, introduced by breathing patterns such as PB or AOP, induce significantly impaired bone development and metabolic changes in human newborns. The enhanced NE outflow from IH exposure may serve a major role in deficient bone growth, and may affect bone and other tissue influenced by that elevation.

Oral characteristics and dietary habits of preterm children: A retrospective study using National Health Screening Program for Infants and Children

The rate of preterm birth is increasing worldwide and preterm infants are susceptible to oral health problems. Hence, this study aimed to investigate the effect of premature birth on dietary and oral characteristics as well as dental treatment experiences of preterm infants using a nationwide cohort study. Data was retrospectively analyzed from National Health Screening Program for Infants and Children (NHSIC) of the National Health Insurance Service of Korea. 5% sample of children born between 2008 and 2012 who completed first or second infant health screening were included and divided into full-term and preterm-birth groups. Clinical data variables such as dietary habits, oral characteristics, and dental treatment experiences were investigated and comparatively analyzed. Preterm infants showed significantly lower rates of breastfeeding at 4-6 months (p<0.001), delayed start of weaning food at 9-12 months (p<0.001), higher rates of bottle feeding at 18-24 months (p<0.001), poor appetite at 30-36 months (p<0.001) and higher rates of improper swallowing and chewing function at 42-53 months (p = 0.023) than full-term infants. Preterm infants also had eating habits leading to poor oral conditions and higher percentage of absence of dental visit compared to full-term infants (p = 0.036). However, dental treatments including 1-visit pulpectomy (p = 0.007) and 2-visit pulpectomy (p = 0.042) significantly decreased when oral health screening was completed at least once. The NHSIC can be an effective policy for oral health management in preterm infants.

Orofacial characteristics of the very low-birth-weight preterm infants

OBJECTIVE

To evaluate the orofacial characteristics of very low-birth-weight preterm infants through anthropometric facial measures, orofacial anteroposterior analysis and the relationship between the gum pads.

METHOD

Orofacial examinations was performed in 154 infants, classified into two groups: Group A comprised 54 very low-birth-weight infants who were examined after clinical stabilization and before hospital discharge, and Group B comprised 100 full-term infants.

RESULTS

The average anthropometricmeasurements in millimetres for Group A and Group B were as follows: upper third:30.2 and 31.1; middle third: 24.2 and 25.9; lower third: 27.6 and 29.9; facial width: 64.8and 81.4. Regarding the orofacial anteroposterior analysis, the results showed that in99% of these infants, the mandible was in a retrognathic position relative to the maxilla.Group A and Group B had the following distributions of the relationship between thegum pads: overbite-overjet: 43% and 77%; overjet: 39% and 17%; open bite: 15% and3%; end-to-end: 2% and 1%; overbite: both 2%.

CONCLUSION

The very low-birth-weight preterm infants showed the upper third with the highest values in the facialharmony analysis, followed by the lower third and the middle third; and exhibited themandible in a retrognathic position relative to the maxilla, and with overbite-overjet themost prevalent type of gum pad relationship. The study emphasizes the importance of orofacial examination during neonatal hospitalization and the investigation of birth weight and gestational age in a multidisciplinary therapeutic approach that includes orofacial neonatal evaluation and actions that promote oral health, besides foster follow-up studies.