Dental microbrush tips: absence of acute cytotoxicity and NF-κB activation in human oral cells.

Dental microbrushes are widely used in adhesive and restorative dentistry; however, flocked nylon designs have been reported to release fibers during clinical manipulation. While such remnants have been discussed in the context of bonding integrity, their potential biological impact on adjacent oral soft tissues remains unclear. The present study investigated the cytotoxic and inflammatory effects of commercially available flocked nylon and elastomer-based dental microbrushes on primary human gingival fibroblasts and HSC-2 oral epithelial cells. Cells were exposed to six microbrush types under direct contact conditions for 24 h. Cell viability was assessed by MTT assay and trypan blue exclusion. Inflammatory activation was evaluated by reverse transcription-quantitative PCR analysis of IL6, IL8 (CXCL8), CCL8, and CCL20 expression, CXCL8 protein quantification by ELISA, and immunofluorescence analysis of NF-κB p65 nuclear translocation. Pro-inflammatory stimulation with IL-1β and TNF-α served as a positive control. None of the tested microbrushes significantly reduced cell viability or induced transcriptional upregulation of inflammatory mediators. CXCL8 protein secretion remained unchanged, and NF-κB signaling was not activated following microbrush exposure. In contrast, cytokine stimulation robustly induced inflammatory responses, confirming the sensitivity of the experimental model. Within the limitations of this in vitro model, commercially available dental microbrushes did not trigger measurable cytotoxicity or pro-inflammatory signaling in oral soft tissue cells. These findings support the short-term biological compatibility of the investigated materials while highlighting the need for further studies addressing chronic exposure, inflammatory priming, and immune cell involvement.