Dear Editor: We have read with a great interest the article by Gupta et al. [1] who performed a meta-analysis exploring the association between chronic mechanical irritation and oral squamous cell carcinoma. The conclusion of the meta-analysis is that chronic oral mucosa irritation has a significant association with oral squamous cell carcinoma, and the nature of association could be that of a potential co-factor (dependent risk factor) rather than an independent risk factor. Read more in PDF.