Background: Increase in nicotine pouch (NP) users, particularly among the young, is a matter of concern requiring a comprehensive understanding of its short- and long-term oral health implications. The objective of this research was to systematically review potential oral side-effects associated with NP usage. Methods: This systematic review was conducted following the PRISMA guidelines. Databases (Medline via PubMed, Scopus, Cochrane Trial, and Google Scholar) were searched for relevant studies up to February 2024. Modified Newcastle-Ottawa Scale (NOS) and the Risk Of Bias In Non-randomized Studies - of Exposure (ROBINS-E) tool were used to assess the quality and bias of the included studies. Results: Three studies were included for this review, two from Europe and one from USA, and considered of a total of 190 participants. All studies were deemed to have a high risk of bias. Participants used NP for periods ranging from 1 month to 10 years. Among these studies, only one study provided information on the usage pattern between 1 and 5 units for an average of 11 ± 7 min per session. Oral mucosal changes at the site of placement were common among NP users. Oral lesions varied from slight wrinkling to various white lesions, seemingly related to the NP units consumed per day and their duration of usage. Other oral side effects included dry mouth, soreness, gingival blisters, and a strange jaw sensation. Conclusions: Research on the use of NP and its effect on oral health are currently limited. The use of NP should take into consideration the short-and-long-term effects, especially on oral health. Further studies are crucial to understand oral health implications associated with NP usage. Systematic review registration: PROSPERO Registration number CRD 42,024,500,711.

Though the oral cavity is anatomically proximate to the nasal cavity and acts as a key reservoir of EBV habitation and transmission, it is still unclear whether EBV plays a significant role in oral carcinogenesis. Many studies have detected EBV DNA in tissues and exfoliated cells from OSCC patients. However, very few studies have investigated the expression of functional EBV proteins implicated in its oncogenicity. The most studied are latent membrane protein 1 (LMP-1), a protein associated with the activation of signalling pathways; EBV determined nuclear antigen (EBNA)-1, a protein involved in the regulation of gene expression; and EBV-encoded small non-polyadenylated RNA (EBER)-2. LMP-1 is considered the major oncoprotein, and overexpression of LMP-1 observed in OSCC indicates that this molecule might play a significant role in oral carcinogenesis. Although numerous studies have detected EBV DNA and proteins from OSCC and oral potentially malignant disorders, heterogeneity in methodologies has led to discrepant results, hindering interpretation. Elucidating the exact functions of EBV and its proteins when expressed is vital in establishing the role of viruses in oral oncogenesis. This review summarises the current evidence on the potential role of EBV in oral oncogenesis and discusses the implications as well as recommendations for future research.