The purpose of this study was to examine the response of the zygomaticomaxillary suture (ZMS) to experimental malocclusion in rats. Thirty-two male Wistar rats were divided into two groups. Malocclusion was produced in the experimental group (n = 20) by gluing a wire, 1 mm in diameter, on the upper left first molar. Duration of the procedure was 20 min. In the control group (n = 12), rats were forced to open their mouths for the same time as in the experimental group. Histomorphological changes of the ZMS were examined at intervals of 1, 2, 4 and 8 weeks. The specimens were stained with hematoxylin-eosin and Mallory’s azan. The suture in the control group showed a regular functional arrangement of component fibers, and osteoblasts lined the periphery of new bone at the inner half of the suture. On the untreated side in the experimental group, osteoclasts were most abundant after 2 weeks. Histomorphometric quantification of the sutural width revealed that, at the inner half of the suture, the width of the sutural space on the treated side in the experimental group was greater than that in the control group after 4 weeks (p < 0.05). The argyrophilic nucleolar organizer region (AgNOR) technique was used to investigate the transcriptional activity of fibroblasts in the suture. At the inner half of the suture, the number of AgNORs on the untreated side in the experimental group was greater than that on the treated side and that in the control group after 2 weeks (p < 0.05). Around the tip of the suture and at the outer half of the suture, there was no appreciable difference in the AgNOR number between the experimental and control groups. It was concluded that unilateral changes in occlusion had different effects on the treated and untreated sides of the ZMS. Moreover, the inner and outer halves of the suture showed different histological changes in response to experimental malocclusion.

Keywords:
Malocclusion, Zygomaticomaxillary suture, Histomorphometry, Argyrophilic nucleolar organizer region, Wistar rat
1.
Abe, Y. (1996) A histomorphometric study of AgNORs in cellular alterations of junctional and pocket epithelia in experimental periodontitis. Jpn J Oral Biol 38: 21–31.
2.
Cabrini, R.L., A.E. Schwint, A. Mendez, F. Femopase, H. Lanfranchi, M.E. Itoiz (1992) Morphometric study of nucleolar organizer regions in human oral normal mucosa, papilloma and squamous cell carcinoma. J Oral Pathol Med 21: 275–279.
3.
Crocker, J., P. Nar (1987) Nucleolar organizer regions in lymphomas. J Pathol 151: 111–118.
4.
Crocker, J., N. Skilbeck (1987) Nucleolar organizer region associated proteins in cutaneous melanotic lesions: A quantitative study. J Clin Pathol 40: 885–889.
5.
Dahlberg, G. (1940) Statistical Methods for Medical and Biological Students. New York, Interscience Publications.
6.
DuBrul, E.L. (1980) Sicher’s Oral Anatomy. St Louis, Mosby.
7.
Ferrari, C.S., S.W. Herring (1995) Use of a bite-opening appliance in the miniature pig: Modification of craniofacial growth. Acta Anat 154: 205–215.
8.
Forbes, D.P., S. Al-Bareedi (1986) Inhibition of secondary cartilage of the intermaxillary suture in Sprague-Dawley rats following the enucleation of maxillary molars. J Craniofac Genet Dev Biol 6: 73–88.
9.
Fukuda, J., H. Yamasaki, K. Onizuka, T. Kikuta, K. Hida, N. Yamada (1984) Changes of the temporomandibular joint following the occlusal disharmony in monkeys. Effect of the inadequate crown. J Kyushu Dent 38: 148–156.
10.
Hall, P.A., J. Crocker, A. Watts, A.G. Stansfeld (1988) A comparison of nucleolar organizer region staining and Ki-67 immunostaining in non-Hodgkin’s lymphoma. Histopathology 12: 373–381.
11.
Herring, S.W. (1972) Sutures – A tool in functional cranial analysis. Acta Anat 83: 222–247.
12.
Hinton, R.J. (1988) Response of the intermaxillary suture cartilage to alterations in masticatory function. Anat Rec 220: 376–387.
13.
Hirabayashi, S., K. Harii, A. Sakurai, E.K. Takaki, O. Fukuda (1988) An experimental study on craniofacial growth in a heterotopic rat head transplant. Plast Reconstr Surg 82: 236–243.
14.
Katsaros, C., S. Kiliaridis, R. Berg (1994) Functional influence on sutural growth. A morphometric study in the anterior facial skeleton of the growing rat. Eur J Orthod 16: 353–360.
15.
Kawakami, T., M. Nishimoto, Y. Matsuda, T. Deguchi S, Eda (1996) Histological suture changes following retraction of the maxillary anterior bone segment after corticotomy. Endod Dent Traumatol 12: 38–43.
16.
Kiliaridis, S., C. Engstrom, B. Thilander (1988) Histochemical analysis of masticatory muscle in the growing rat after prolonged alteration in the consistency of the diet. Arch Oral Biol 33: 187–193.
17.
Koskinen, L. (1977) Adaptive sutures. Proc Finn Dent Soc 73 (suppl 10–11): 3–80.
18.
Linge, L. (1972) Tissue reactions incident to widening of facial sutures. Trans Eur Orthod Soc 48: 487–497.
19.
Melsen, B., J.A. McNamara, D.C. Hoenie (1995) The effect of bite-blocks with and without repelling magnets studied histomorphometrically in the rhesus monkey (Macaca mulatta). Am J Orthod Dentofacial Orthop 108: 500–509.
20.
Miyawaki, S., D.P. Forbes (1987) The morphologic and biochemical effects of tensile force application to the interparietal suture of the Sprague-Dawley rat. Am J Orthod Dentofacial Orthop 92: 123–133.
21.
Moss, M.L. (1957) Experimental alteration of sutural area morphology. Anat Rec 127: 569–584.
22.
Moss, M.L. (1961) Extrinsic determination of sutural area morphology in the rat calvaria. Acta Anat 44: 263–272.
23.
Nanda, R., W. Hickory (1984) Zygomaticomaxillary suture adaptations incident to anteriorly-directed forces in rhesus monkeys. Angle Orthod 54: 199–210.
24.
Oudhof, H.A.J. (1982) Sutural growth. Acta Anat 112: 58–68.
25.
Oudhof, H.A.J., I.S. Markens (1982) Transplantation of the interfrontal suture in the Wistar rat. Acta Anat 113: 39–46.
26.
Ploton, D., M. Menager, P. Jeannesson, G. Himber, F. Pigeon, J.J. Adnet (1986) Improvement in the staining and in the visualization of the argyrophilic proteins of the nucleolar organizer region at the optical level. Histochem J 18: 5–14.
27.
Prahl, B. (1968) Sutural Growth. Investigation on the Growth Mechanism of the Coronal Suture and Its Relation to Cranial Growth in Rat; thesis University of Nijmegen.
28.
Southard, K.A., D.P. Forbes (1988) The effects of force magnitude on a sutural model: A quantitative approach. Am J Orthod Dentofacial Orthop 93: 460–466.
29.
Sukekawa, R., I. Itoh (1995) Histological study of the frontopremaxillary suture in mice. Jpn J Oral Biol 37: 419–425.
30.
Sukekawa, R., I. Itoh (1997) Histomorphology and its experimental alteration of coronal suture in mice. Jpn J Oral Biol 39: 155–163.
31.
Young, R.W. (1959) The influence of cranial contents on postnatal growth of the skull in the rat. Am J Anat 105: 383–415.
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2000
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