Ki-67 expression in pericoronal tissues of impacted mandibular third molars

Abstract

The study was performed to histologically and immunohistochemically evaluate soft tis¬sue pathologic changes in pericoronal epithelial tissues of impacted mandibular third molars that did not exhibit pathologic pericoronal radiolucency and to clarify the role of Ki-67 expression for separation between healthy follicle and dentigerous cyst. Fifty pericoronal tissues associated with completely impacted mandibular third molars were submitted for histologic examination by each of 2 pathologists after surgical tooth re¬moval was performed. Biopsy samples were fixed in 10% buffered neutral formalin solu¬tion and embedded in paraffin blocks. Sections (4-6 μm) were obtained from the paraffin block and to evaluate the expression of Ki-67 sections were immunostained anti-Ki-67 primary antibody and streptavidin-biotin complex system. The incidence of normal tis¬sue of a dental follicle was 22%, and the incidence of dentigerous cyst was 52%, and the incidence of chronic nonspecific inflammatory tissue was 26%. Ki-67 expression was positive in 19 of 26 lining epithelia in cystic specimens, in 4 of 13 chronic nonspecific inflammatory tissue specimens, and in 0 of 11 healthy follicular specimens. These find¬ings suggest that the majority of cystic specimens demonstrated proliferative activity, therefore the incidence of dentigerous cyst associated with impacted third molar teeth is high and proliferative marker may be played a role in diagnosis of dentigerous cyst as¬sociated with radiographically normal third molar impactions.

Keywords

• Impacted tooth
• Third molar
• Dental follicle
• Dentigerous cyst
• Ki-67
• Cell neoplastic transformation

References

1. Adelsperger, J., Campbell, J.H., Coates, D.B., Summerlin, D.J., Tomich, C.E., 2000. Early soft tissue pathosis associated with impacted third molars without pericoronal radiolucency. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 89, 402-406.
2. Baykul, T., Saglam, A.A., Aydin, U., Basak, K., 2005. Incidence of cystic changes in radiographically normal impacted lower third molar fol licles. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 99, 542-545.
3. Brkic, A., Mutlu, S., Berberoglu, H.K., Olgac, V., 2010. Pathological changes and immunoexpression of p63 gene in dental follicles of asymp tomatic impacted lower third molars: An immunohistochemical study. J. Craniofac. Surg. 21, 854-857.
4. Curran, A.E., Damm, D.D., Drummond, J.F., 2002. Pathologically significant pericoronal lesions in adults: Histopathologic evaluation. J. Oral Maxillofac. Surg. 60, 613-617.
5. Eliason, S., Heimdahl, A., 1989. Pathologic changes related to long term impaction of third molars: A radiographic study. Int. J. Oral. Maxillofac. Surg. 18, 210-212.
6. Gerdes, J., Lemke, H., Baisch, H., Wacker, H.H., Schwab, U., Stein, H., 1984. Cell cycle analysis of a cell proliferation-associated human nuclear antigen defined by the monoclonal antibody Ki-67. J. Immunol. 133, 1710-1715.
7. Glosser, J.W., Campbell, J.H., 1999. Pathologic changes in soft tissues associated with radiographically normal third molar impactions. Br. J. Oral Maxillofac. Surg. 37, 259-260.
8. Gorlin, R.J., 1957. Potentialities of oral epithelium manifested by mandibular dentigerous cysts. Oral Sur g. Oral Med. Oral Pathol. 10, 271

9. Leitner, C., Hoffmann, J., Kröber, S., Reinert, S., 2007. Low-grade malignant fibrosarcoma of the dental follicle of an unerupted third molar without clinical evidence of any follicular lesion. J. Craniofac. Sur g. 35, 48-51.
10. Piattelli, A., Lezzi, G., Fioroni, M., Santinelli, A., Rubini, C., 2002. Ki-67 expression in dentigerous cysts, unicystic ameloblastomas, and amelo blastomas arising from dental cysts. J. Endod. 28, 55-58.
11. Rakprasitkul, S., 2001. Pathologic changes in the pericoronal tissues of unerupted third molars. Quintessence Int. 32, 633-638.
12. Saito, K., Mori, S., Tanda, N., Sakamoto, S., 1999. Expression of p53 protein and Ki-67 antigen in gingival hyperplasia induced by nifedipine and phenytoin. J. Periodontol. 70, 581-586.
13. Sano, K., Yoshida, S., Ninomiya, H., Ikeda, H., Ueno, K., Sekine, J., Iwamoto, H., Uehara, M., Inokuchi, T., 1998. Assessment of growth poten tial by MIB-1 immunohistochemistry in ameloblastic fibroma and related lesions of the jaws compared with ameloblastic fibrosarcoma. J. Oral Pathol. Med. 27, 59-63.