Experimental tooth movement in murines: study period and direction of microscopic sections

Ana Carolina Cuzzuol FRACALOSSI, Milton SANTAMARIA JR, Maria Fernanda Martins-Ortiz CONSOLARO, Alberto CONSOLARO

Aim: This study aims to elucidate the relevant microscopic aspects of induced tooth movement in murines with regard to: (1) different study periods; and (2) transverse and longitudinal directions of microscopic sections. Experimental studies on induced tooth movement in murines use variable study periods and directions of microscopic sections, including those studies that speciically use the model adopted by Heller and Nanda in 1979. This manuscript was prepared in order to contribute to: (1) selection of the best study design for future studies on induced tooth movement in murines, and (2) improve the analysis criteria to be used by other investigators. Methods: The study was conducted on 50 male Wistar rats with 90 days of age, submitted to induced tooth movement for periods of 3, 5, 7 and 9 days. The maxillary left irst molar was submitted to mesial inclination by application of 75cN of force. Qualitative microscopic analysis evaluated the tissue and cellular phenomena secondary to induced tooth movement, at the different study periods and on transverse and longitudinal sections. Results: Among the phenomena investigated, hyaline areas of periodontal ligament were mostly observed at 5 days, and root resorptions were remarkable and well delineated at 9 days. Both phenomena affected mainly the distal roots, especially the distobuccal root. Conclusion: Considering the present objective, study periods of 5 to 9 days and transverse microscopic sections may be suggested for future studies on this subject.

Keywords: Induced tooth movement. Bone resorption. Root resorption.

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