Participation of osteoclastogenic factors in immunopathogenesis of human chronic periapical lesions.

BACKGROUND: Chronic periapical lesions (CPLs) are common lesions of the oral cavity and are the result of caries, tooth fracture, iatrogenic causes, or factors causing contamination and pulp necrosis. Inflammatory cells participate in the expansion of CPLs by releasing factors that stimulate or inhibit osteolytic activity. The objective of this study was to investigate the participation of RANKL, TNF-α, cathepsin K, IL-33, and OPG in the development of radicular cysts (RCs) and periapical granulomas (PGs). METHODS: Paraffin-embedded sections of 30 RCs and 22 PGs were submitted to immunohistochemistry. RESULTS: Immunoexpression of the proteins studied was observed in the epithelium and capsule of RCs, as well as in connective tissue of PGs. The expression of the osteoclastogenic factors studied differed significantly in RCs and PGs (P < .001), with lower expression of OPG in RCs. In PGs, the lowest expression was observed for cathepsin K. Comparison of the 2 lesions showed a similar participation of RANKL and IL33, while a significant difference was observed for OPG (P < .001), TNF-α (P = .002), and cathepsin K (P = .016). No association of the expression of the proteins with lesions size was observed. CONCLUSIONS: This study demonstrated the participation of RANKL, TNF-α, IL-33, cathepsin K, and OPG in the development of RCs and PGs, with emphasis on the highest immunoreactivity of cathepsin in RCs and TNF-α and OPG in PGs. OPG possibly determines the slower growth of PGs compared to RCs.

A Twenty-year Survey of Pathologic Reports of Two Common Types of Chronic Periapical Lesions in Shiraz Dental School.

BACKGROUND AND AIMS: Accurate differential diagnosis between radicular cysts and periapical granulomas cannot be made from radiographs alone. Histological prevalence studies, therefore, assume special importance and may aid the clinician in making judgments regarding therapy. The incidence of radicular cysts has ranged with wide discrepancies in data. The purpose of this study was to evaluate recorded pathologic reports of two common types of chronic periapical lesion in Shiraz Dental School. MATERIALS AND METHODS: In this study, biopsy reports of 227 specimens of chronic periapical lesions were reviewed. The following information was extracted from each report: patient's gender, age, tooth associated with the lesion and the pathological diagnosis. Probable significant differences in the occurrence of lesions between different ages and genders were analyzed using chi-square test. RESULTS: 15.9% of the lesions were granulomas, and 84.1% were cysts. A slight difference in the occurrence of the lesions was found between males and females with no statistical significance (P > 0.005). The highest incidence of both lesions was in the third decade of life. No significant differences were found in age distribution of the lesions. The most common location for two lesions was the maxillary anterior teeth. CONCLUSION: Histological differentiation between cysts and granulomas is not always accurate and serial sectioning of excisional biopsies is more valuable than randomized sectioning of curetted biopsies.