Intermittent hypoxia causes mandibular growth retardation and macroglossia in growing rats
Am J Orthod Dentofacial Orthop 2017;151:363-71
In this study, we aimed to examine the role of intermittent hypoxia (IH) in dentofacial morphologic changes in growing rats. Methods: Seven-week-old male rats were exposed to IH at 20 cycles per hour (nadir of 4% oxygen to peak of 21% oxygen) for 8 hours per day for 6 weeks. Control rats were exposed to normoxia (N). Maxillofacial growth was compared between the 2 groups by linear measurements on cephalometric radiographs. To examine the dental arch morphology, study models and microcomputed tomography images of the jaws were taken. Additionally, tongue size was measured. Results: The gonial angle and the ramus of the mandible were smaller in the IH group than in the N group, whereas the body weights were not different between the 2 groups. Morphometric analysis of the dentition showed a significantly wider mandibular dentition and narrower maxillary dentition in the IH than in the N group. The relative width (14.2 %) and length (tongue apex to vallate papillae, 13.5 %) of the tongue to the mandible were significantly greater in the IH group than in the N group. Conclusions: IH induced dentofacial morphologic discrepancies in growing rats.