Eruption of a permanent mandibular canine in a 5-year-old boy.

The premature eruption of a mature mandibular permanent canine is described in a healthy 5-year-old boy with developmental absence of the primary predecessor. The effects of early loss or missing primary teeth on eruption timing of the permanent successors are discussed. The very early maturation of the permanent canine appears to be a unique oddity, and there are no reports in the literature of eruption of this type of secondary tooth at such an early chronological age.

The effects of orthognathic surgery on pharyngeal airway dimensions and quality of sleep.

Orthognathic surgery has been associated with airway narrowing and induction of sleep-related breathing disorders. Therefore, the pharyngeal airway dimensions of 32 orthognathic surgery cases were prospectively investigated, and the relationship between the surgery and sleep quality assessed. Digitized lateral cephalometric radiographs were used to compare oropharyngeal airway morphologies before and after surgery. Patients were assessed in two main surgical groups based on sagittal jaw relationship. A questionnaire was used to assess changes in daytime sleepiness. The mandibular surgery cases were also assessed by overnight domiciliary sleep monitoring. A significant decrease in the retrolingual airway dimension was found in all patients after mandibular setback surgery and a significant increase in this dimension after mandibular advancement. The questionnaire and sleep study revealed no significant changes in snoring incidence or apnoeic events after mandibular setback surgery. For the mandibular advancement group, a change in sleep quality was found, but only in cases with signs of a pre-existing sleep disorder.