Early risk factors for posterior crossbite and anterior open bite in the primary dentition.

OBJECTIVE: To investigate risk factors specific to posterior crossbite and anterior open bite at the age of 3 years. MATERIALS AND METHODS: The study included 422 children of the French EDEN mother-child cohort. The main outcomes were the presence of posterior crossbite and anterior open bite assessed by dentists at 3 years. Social characteristics (collected during pregnancy), neonatal characteristics (collected at birth), duration of breast-feeding (collected prospectively), sucking habits at 3 years, and open lips (as a proxy for mouth breathing) were studied and two logistic regressions conducted. RESULTS: Preterm birth appears to be a risk factor specific for posterior crossbite (OR: 3.13; 95% CI: 1.13-8.68), whereas small for gestational age seems to be associated with a lower risk of posterior crossbite (OR: 0.32; 95% CI: 0.12-0.87). Ongoing pacifier or thumb sucking at 3 years is a risk factor for both posterior crossbite and anterior open bite. CONCLUSIONS: Children born preterm seem to be more at risk for posterior crossbite than those born at term. Different mechanisms may be involved in posterior crossbite and anterior open bite.

A laser Doppler study of gingival blood flow variations following periosteal stimulation.

OBJECTIVES: Evaluation of the modifications occurring in human gingival blood flow following periosteal stimulation. MATERIAL AND METHODS: Laser Doppler was used to measure the gingival blood flow (GBF). The reproducibility of the technique was validated by comparing measures made at intervals of 1 week. Sensitivity was verified by recording GBF before and after injection of an anesthetic containing a vasoconstrictor. Finally, 12 patients were subjected to GBF measurements before and 8 days after periosteal stimulation prior to gingival grafting. RESULTS: The laser Doppler accurately measured GBF. Measurements made at day 0 and day 7 were not statistically different (p=0.60). After injection of an anesthesic solution containing vasoconstrictor, the laser Doppler recorded a sharp decrease of the GBF (p=0.04). The patient that underwent periosteal stimulation showed statistically significant increases (p=0.02) in GBF before and 1 week post-stimulation. CONCLUSION: Periosteal stimulation induces significant increases in the GBF after 1 week.