Early cellular reactions in mechanically stimulated gingival connective tissue.
OBJECTIVE
The aim of this study was to describe early cellular reactions occurring in mechanically stimulated gingival connective tissue.


METHODS
Elastic bands were inserted between the maxillary first and second molars of male rats aged 8 weeks, which were pulse-labeled with 3H-thymidine and subsequently killed in groups together with labeled control animals after periods of 1-168 hours. Autoradiographs were prepared from plastic mesiodistal sections and parameters of cell proliferation determined in gingival connective tissue sampling areas coronal to the interdental bone crest and in the central zone of the body of the papilla between the second and third molars. The incidence of macrophages was assessed in identical tissue compartments of adjacent sections by counting nonspecific esterase-positive cells, and the vascular reaction was evaluated by measuring vascular lumen area and endothelial cell proliferation.


RESULTS
Fibroblast and endothelial cell proliferation was significantly increased in mechanically stimulated tissue (p < 0.05) compared with controls, the incidence of macrophages was very low both in control and in stimulated specimens, and an immediate but transient vasodilatation occurred as part of the gingival tissue response to stimulation (p < 0.05).


CONCLUSIONS
The results question the role of macrophages at the early stages of gingival remodeling incident to mechanical stimulation.
Zentner
A
A
Department of Orthodontics, University of Mainz, Germany. Zentner@kieferortho.klinik.uni-mainz.de
Panagiotis
K
K
Heaney
T
T
D000818:Animals; D002455:Cell Division; D003238:Connective Tissue / Q000293:injuries*; D004727:Endothelium; D005347:Fibroblasts; D005881:Gingiva / Q000293:injuries*; D008264:Macrophages / Q000502:physiology*; D008297:Male; D008963:Molar; D051381:Rats; D011919:Rats, Inbred Strains; D014087:Tooth Movement Techniques; D014664:Vasodilation