Doenças gengivais não induzidas por placa: um estudo multicêntrico sul-americano

Abstract

The present thesis is composed of five scientific articles, all focused on the clinicopathological study of non–plaque-induced gingival lesions. Article 1 presents a retrospective and observational study that analyzed 270 cases of peripheral ossifying fibroma (POF), diagnosed between 1999 and 2020 in an oral pathology service in Brazil. Morphological analysis, conducted using a semiquantitative methodology, assessed mesenchymal cellularity, inflammatory infiltrate, ulceration, and types of mineralized tissue. The findings showed a predominance in females (71.9%), with the most frequent site being the anterior upper gingiva (29.1%) and an association with incisors (49%). The most frequently found mineralized tissues were mature bone (86.7%) and immature bone (52.6%). A significant association was observed between immature bone deposition and lesions ≤ 1.7 cm in size (p = 0.041), as well as between immature bone and cementum-like tissue in lesions with an evolution time ≤ 16 months (p < 0.001). Additionally, there was an association between immature bone and hypercellularity of the mesenchymal component (p < 0.001), and between dystrophic calcification and ulceration (p < 0.001). Article 2 described a clinicopathological case of primary gingival rhabdomyosarcoma in an adult woman, whose clinical appearance mimicked a benign reactive lesion. The definitive diagnosis was established through biopsy and immunohistochemistry. Despite surgical resection followed by chemoradiotherapy, the patient experienced recurrence within seven months and died after further surgery and radiotherapy. The case underscores the importance of histopathological and immunohistochemical diagnosis to avoid underdiagnosis of malignant neoplasms in the gingiva. Article 3 consisted of a systematic review with meta-analysis aimed at estimating the global frequency of peripheral odontogenic fibroma (POdF) in oral pathology services. A total of 26 studies were included, selected from six electronic databases and gray literature. The results showed that POdF accounts for 0.05% of all biopsied oral lesions (95% CI: 0.03–0.06; I² = 80.8%), 2.31% of odontogenic tumors (95% CI: 1.57–3.06; I² = 87.2%), and 52.68% of peripheral odontogenic tumors (95% CI: 36.99–68.36; I² = 87.9%). The certainty of the evidence ranged from moderately low to very low due to methodological limitations of the included studies. It was concluded that POdF is one of the most frequent lesions among peripheral odontogenic tumors. Article 4 evaluated, in a multicenter and retrospective manner, the frequency and clinical features of reactive gingival lesions (RGLs) diagnosed in ten South American centers between 1996 and 2022. RGLs accounted for 6.1% of oral biopsies, with a predominance in females (68.1%; p ≤ 0.0001) and a median age of 47 years. The most common lesions were inflammatory fibrous hyperplasia (IFH) (40.8%), fibrous hyperplasia (FH) (21.3%), and pyogenic granuloma (PG) (16.1%). The anterior upper gingiva was the most frequently affected site (28.2%), followed by the posterior lower gingiva (26.2%) and anterior lower gingiva (24.4%). Most lesions were asymptomatic (88.6%; p ≤ 0.0001), sessile (64.9%; p ≤ 0.0001), and showed reddish (42.1%) or pink (26.4%; p ≤ 0.0001) coloration. Article 5 analyzed the prevalence and demographic characteristics of non–plaque-induced gingival diseases (NPIGDs) based on 11,624 cases diagnosed in ten Oral Pathology centers in Brazil and Argentina between 1996 and 2022. The most prevalent categories were reactive lesions (74.2%), potentially malignant oral disorders (8.6%), and malignant neoplasms (6.0%). The most frequent lesions were IFH (30.3%), FH (15.8%), PG (11.9%), POF (8.3%), peripheral giant cell lesion (6.5%), and squamous cell carcinoma (4.9%). Lesions were more frequent in females (66.2%), with a median age of 50 years and predominance in the lower gingiva (52.9%). Smoking was significantly associated with malignant lesions (77.5%; p ≤ 0.0001) and potentially malignant lesions (83.8%; p ≤ 0.0001). Taken together, the results of these five studies significantly contribute to the epidemiological, clinical, and diagnostic knowledge of non–plaque-induced gingival lesions in South American populations. They also reinforce the need for future revisions in current periodontal classifications and highlight the importance of histopathological examination in dental practice.