How harmful are e-cigarettes to the head and neck cells?

Data sources Medline, Cumulative Index to Nursing and Allied Health Literature, Chemical Abstracts Plus, Dentistry and Oral Sciences and Web of Science databases, as well as grey literature, were searched for publications up to December 2020.Study selection Search terms and concepts were mentioned in line with clear PICOS (population, intervention, comparison, outcomes and study) criteria. Inclusion and exclusion criteria were outlined. All study designs were considered.Data extraction and synthesis Two independent reviewers screened 233 articles using Rayyan software. In total, 49 full-text articles were retrieved.Results Overall, 18 studies fit the inclusion criteria, of which two were clinical trials and sixteen were in vitro research. Varying strengths of nicotine concentration were examined for toxicity on head and neck cells. The use of electronic cigarettes (e-cigarettes) caused changes to cell size and shape and reduced cell viability and cell proliferation.Conclusions Although less harmful than tobacco smoke, e-cigarettes appear to induce damaging changes in head and neck cells.The article is available via Open Access. Click on the 'Additional link' above to access the full-text.accepted version (6 months), submitted versio