Title

Investigation of foreign materials in gingival biopsies: a clinicopathologic, energy-dispersive microanalysis, and an in-vitro study.

Lead Author Affiliation

International Dental Studies

Lead Author Status

Doctoral Student

Presentation Category

IDS Student Presentations

Introduction/Context

Foreign body gingivitis (FBG) has been previously described as a localized inflammatory reaction associated with the presence of foreign material in gingival tissues. However, among the gingival biopsies submitted to the Pacific Oral Pathology Laboratory (POPL) for diagnosis, we have identified foreign material in lesions that are markedly keratinized and described clinically as white plaques rather than inflamed lesions. We evaluated the clinical and histopathological features of these lesions and the composition of the foreign particles.

Methods

86 gingival biopsies containing foreign material were retrieved from the POPL archives. Composition of these particles was identified by energy-dispersive x-ray spectroscopy (EDX). Further, primary human gingival fibroblasts (HGF) were stimulated with silica (SiO2) micro-particles to investigate the production of COL-1, MMP2 and inflammatory cytokines.

Results

Foreign material was most commonly found in women (61%), in the 6th or 7th decade of life, and the clinical lesions were most frequently described as white plaques involving posterior mandibular gingiva. Histopathological examination identified verrucous hyperplasia in 60.5% of the cases and epithelial dysplasia in 28.5% of the cases. EDX microanalysis revealed that Si (94%) followed by Ca (85%) and Al (66%) were the most frequently detected elements in the foreign particles. Silica micro-particles induced higher COL-1 expression and increased MMP-2 activity in HGF, and higher levels of pro-inflammatory cytokines such as IL-6, IL-8 and TGF-ß in a micro-particle-concentration-dependent manner.

Significance/Conclusions

Our study demonstrates that there is a strong association between the presence of foreign material in gingiva and clinically and microscopically demonstrable hyperkeratotic verrucous plaques. Moreover, we found that the most common element in the foreign material is Si which is usually found in the Earth’s crust as silica. Our in vitro findings demonstrate the importance of silica-mediated effects on gingival fibroblasts, suggesting that the presence of silica in gingival biopsies could modulate the host inflammatory response and should be further investigated.

Comments

This work was supported by Interdisciplinary Pilot Project Research Award 03-Activity 116 from the Arthur A. Dugoni School of Dentistry. This work will be presented at the Joint International Association of Oral Pathology and American Academy of Oral and Maxillofacial Pathology Meeting, June 23-28, 2018, Vancouver, Canada.

Location

2nd floor clinic and reception waiting areas

Format

Poster

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May 23rd, 2:00 PM May 23rd, 4:15 PM

Investigation of foreign materials in gingival biopsies: a clinicopathologic, energy-dispersive microanalysis, and an in-vitro study.

2nd floor clinic and reception waiting areas

Foreign body gingivitis (FBG) has been previously described as a localized inflammatory reaction associated with the presence of foreign material in gingival tissues. However, among the gingival biopsies submitted to the Pacific Oral Pathology Laboratory (POPL) for diagnosis, we have identified foreign material in lesions that are markedly keratinized and described clinically as white plaques rather than inflamed lesions. We evaluated the clinical and histopathological features of these lesions and the composition of the foreign particles.