Objective: To investigate morphological changes in the dental arches of acromegaly-like rats recently developed by means of exogenous IGF-I administration.
Design: Human recombinant IGF-I (640microg/day) was continuously administered subcutaneously for 4 weeks by osmotic mini-pumps to 10-week-old male rats (n=6). Control animals were injected with saline alone (n=6). After administration, all the rats were housed for 4 more weeks. Arch width (W), length (L) and angle (theta) in the mandible and maxilla were measured once a week during and after IGF-I administration.
Results: The concentration of circulating IGF-I, and W and theta in the mandible were significantly increased as compared with the control rats. Although the mandibular dental arch stopped expanding once administration ended, it did not return to the control size.
Conclusions: In our acromegaly-like rat model, mandibular dental arch growth is greater in the lateral than antero-posterior direction during and after IGF-I administration.