Periapical Innervation of the Ferret Canine One Year After Pulpectomy

Previous studies have shown that, following removal of the dental pulp and its replacement with a filling material, the nerves in the periapical region proliferate within an area of chronic inflammation. This study examined these responses in the ferret in more detail, both quantitatively and in three dimensions, 12 months after pulpectomy which was followed by obturation with gutta percha and zinc oxide and eugenol sealer. The results were compared with the responses after three months. The basic patterns, in terms of both inflammation and neural proliferation, were similar at the two time periods. Both the sizes of the inflammatory lesions and the degree of neural proliferation were lower at 12 months than at three, although the differences were not significantly different in the small number of specimens examined. Bacterial stains failed to show bacteria either in the apical root canal delta or in the periapical area. It is possible that the persistent inflammation was due to the irritant nature of the obturating materials used but not due to the original tissue damage, since extraction sites, by comparison, healed very quickly. Apparently, following endodontic treatment, chronic periapical inflammation and concomitant neural proliferation can continue for long periods.

[1]  G. R. Holland,et al.  Distribution and morphological characteristics of axons in the periodontal ligament of cat canine teeth and the changes observed after reinnervation , 1991, The Anatomical record.

[2]  G. R. Holland.  The effect of pulpectomy on the longitudinal distribution of nerve fibres in the periodontal ligament of the ferret. , 1991, Archives of oral biology.

[3]  M. Byers,et al.  Effects of injury and inflammation on pulpal and periapical nerves. , 1990, Journal of endodontics.

[4]  M. Byers,et al.  Responses of nerve fibers to pulpal inflammation and periapical lesions in rat molars demonstrated by calcitonin gene-related peptide immunocytochemistry. , 1988, Journal of endodontics.

[5]  M. Byers,et al.  Inflammation of rat molar pulp and periodontium causes increased calcitonin gene‐related peptide and axonal sprouting , 1988, The Anatomical record.

[6]  G. R. Holland.  Periapical innervation of the ferret canine and the local retrograde neural changes after pulpectomy , 1988, The Anatomical record.

[7]  H. J. G. GUNDERSEN,et al.  Some new, simple and efficient stereological methods and their use in pathological research and diagnosis , 1988, APMIS : acta pathologica, microbiologica, et immunologica Scandinavica.

[8]  M. R. Sims,et al.  A transmission electron-microscope stereological study of the blood vessels, oxytalan fibres and nerves of mouse-molar periodontal ligament. , 1987, Archives of oral biology.

[9]  E B Hunziker,et al.  Stereology for anisotropic cells: Application to growth cartilage * , 1986, Journal of microscopy.

[10]  M. Byers.  Sensory innervation of periodontal ligament of rat molars consists of unencapsulated Ruffini‐like mechanoreceptors and free nerve endings , 1985, The Journal of comparative neurology.

[11]  K. Langeland,et al.  Innervation of the inflammatory periapical lesions. , 1981, Oral surgery, oral medicine, and oral pathology.

[12]  J. Linder.  A simple and reliable method for the silver impregnation of nerves in paraffin sections of soft and mineralized tissues. , 1978, Journal of anatomy.

[13]  M. Stefanini,et al.  Fixation of Ejaculated Spermatozoa for Electron Microscopy , 1967, Nature.

[14]  J. Erausquin,et al.  Root canal fillings with zinc oxide-eugenol cement in the rat molar. , 1967, Oral surgery, oral medicine, and oral pathology.

[15]  C. Martinelli,et al.  The innervation of chronic inflammatory human periapical lesions. , 1967, Archives of oral biology.

[16]  S. Seltzer,et al.  A HISTOLOGIC EVALUATION OF PERIAPICAL REPAIR FOLLOWING POSITIVE AND NEGATIVE ROOT CANAL CULTURES. , 1964, Oral surgery, oral medicine, and oral pathology.