Non-Cochrane · aetiology · PM40291822

The effects of electronic smoking on dental caries and proinflammatory markers: a systematic review and meta-analysis.

Tabnjh Abedelmalek Kalefh, Alizadehgharib Sara, Campus Guglielmo, et al. · Frontiers in oral health · 2025 · PubMed · doi:10.3389/froh.2025.1569806

Oral Health Dental cariesAMSTAR 2: not applicable

Full textEvery question was extracted from the full text, figures and supplements by two independent LLM extractors, disagreements adjudicated. Rows cite where in the review the value comes from.

Questions

current version

GRADE rated

No studies

Included studies

linked below

No studies 0 · 0%Ungraded 24 · 100%Very low 0 · 0%Low 0 · 0%Moderate 0 · 0%High 0 · 0%

Ungraded means an effect was reported without a GRADE rating; it is not a gap. No studies means the review found nothing to answer the question. The six categories are a display order, not a score.

Review question

Element	Planned (methods)	Found (results)
Population	Human cells or oral bacteria exposed to e-cigarettes, or humans who use e-cigarettes (any age or sex); includes laboratory studies of oral bacteria or human oral cells	42 study-entries (41 unique): caries stream 25 (14 laboratory, 9 cross-sectional, 2 cohort; published 2014-2024); inflammation stream 17 (mostly cross-sectional, 2 cohort; published 2018-2024); countries include USA, Saudi Arabia, UK, Poland, Kuwait, Egypt, Turkey and others
Intervention	Electronic cigarette use / e-cigarette aerosol or vapour (ENDS, vaping)	E-cigarette use / e-cig aerosol or e-liquid (ENDS/vaping); flavored and unflavored; nicotine and non-nicotine
Comparison	Conventional cigarette smokers (CS) and non-smokers (NS)	Non-smokers (NS) and conventional cigarette smokers (CS); some studies also included dual smokers, waterpipe or heated-tobacco smokers; in vitro controls (unexposed / unflavored e-liquid / cigarette smoke)
Outcomes	Clinically evaluated and user-reported changes in proinflammatory markers and dental-caries-associated variables attributable to e-cigarettes	Meta-analyzed: DMFT/DMFS (3 studies); IL-1β (11), IL-6 (6), IL-8 (6), TNF-α (7), and combined salivary markers (Fig 3A-F). Narrative: untreated caries, dry mouth, caries risk (CAMBRA), pH, sugars, enamel/dentin changes; cariogenic and commensal oral bacteria (9 studies)
Study designs	Observational and interventional studies plus laboratory (in vitro/ex vivo) studies of oral bacteria or human oral cells; any age/sex; English; no time limit. Excluded: reviews/meta-analyses, case reports/series, conference abstracts/posters, comment articles, unclear studies	In vitro/ex vivo laboratory, cross-sectional, cohort/prospective, and a few interventional (before-after switching) studies
Timing	Not specified (no time limit)	Follow-up 6-12 months in the few longitudinal studies; most cross-sectional (single time point)

Search date: September 2024 (initial search April 2024, updated September 2024). Databases: PubMed; Embase; Web of Science; Scopus

Questions and results

E-cigarette use (ENDS / vaping) vs Non-smokers

Population: Humans who use e-cigarettes (adolescents to adults) assessed for dental caries

4 questions

Outcome	Effect	Evidence	Status / GRADE
Dry mouth (xerostomia) Cross-sectional to 12 months Two studies reported more frequent xerostomia (dry mouth) among e-cigarette users than non-smokers, which may raise caries risk, but results were not pooled (ungraded, narrative). Source: Results 'Vaping and dental caries'; Table 1 (refs 23, 27) · same question in other reviews	Narrative synthesis. E-cigarette users reported dry mouth more frequently than non-smokers: Chaffee 2021 dry mouth 12% (OR 1.4); Alhajj 2022 dry mouth 33.3% in e-cigarette users vs 23.4% in controls. Not pooled.	2 studies	Ungraded
Dental caries experience (DMFT/DMFS index) Cross-sectional to 6 months A meta-analysis of 3 studies compared DMFT/DMFS in e-cigarette users vs non-smokers, but the pooled effect appears only in Figure 3A (unavailable) and heterogeneity was very high (I2=98%); the effect of vaping on dental caries remains unclear (ungraded). Source: Results 'DMFT' and 'Meta-analysis'; Figure 3A; Table 1 (refs 22, 29, 30) · same question in other reviews	Cohen's d 0.93 [-1.11, 2.98]	3 studies	Ungraded
Untreated dental caries and caries risk Cross-sectional Across individual cross-sectional studies, e-cigarette users tended to have more untreated caries and higher caries risk than non-smokers (per-study OR ~2.0-4.2), but results were not pooled (ungraded, narrative). Source: Results 'Vaping and dental caries'; Discussion; Table 1 (refs 7, 14, 17) · same question in other reviews	Narrative synthesis (not meta-analyzed). E-cigarette users had more untreated caries and higher caries risk than non-smokers in individual studies: Vemulapalli 2021 untreated-caries OR 2.04 (non-smokers as reference);…	3 studies	Ungraded
DMFT/DMFS score Overall Population: People who use electronic cigarettes The review reports that the effect of vaping on dental caries remains unclear. Source: Results, DMFT; Figure 3A · same question in other reviews	Cohen's d 0.93 [-1.11, 2.98]	3 studies	Ungraded

E-cigarette aerosol / e-liquid exposure (flavored and unflavored; nicotine and non-nicotine) vs Unexposed controls / unflavored e-liquid / conventional cigarette smoke

Population: Oral bacteria (streptococci), dental hard tissue (enamel/dentin) and e-liquids studied in vitro/ex vivo (with a few clinical microbiome studies)

3 questions

Outcome	Effect	Evidence	Status / GRADE
Enamel/dental hard-tissue changes and e-liquid cariogenic properties (demineralization, colour change, pH, sugar content, metals) In vitro evidence suggests e-liquids are often acidic and sugar-containing and can alter enamel/dentin colour and properties, supporting a plausible cariogenic effect, but findings are heterogeneous and not pooled (ungraded, narrative). Source: Results 'Vaping and dental caries' / 'Data synthesis'; Table 1 (refs 12, 13, 21, 24, 25, 26, 28) · same question in other reviews	Narrative synthesis. In vitro studies showed e-liquids can be acidic (Fairchild 2021: 84% of vapes pH<5.5) and contain sugars (Fagan 2018 sucrose ~125 ug/ml; Kubica 2014 sucrose 0.76-72.93 ug/g), and e-cigarette…	NR	Ungraded
IL-1β level Overall Population: People who use electronic cigarettes The review reports no e-cigarette effect on salivary IL-1β, while findings for GCF may differ. Source: Results, IL-1β; Figure 3B · same question in other reviews	Cohen's d 0.98 [-0.03, 1.99]	11 studies	Ungraded
Cariogenic and commensal oral bacteria (S. mutans and commensal streptococci growth, adhesion, biofilm) Most in vitro studies indicate e-cigarette aerosol/e-liquid (especially flavored/high-concentration) disrupts normal oral flora and favors cariogenic S. mutans growth and biofilm, plausibly increasing caries risk; not pooled (ungraded, narrative). Source: Results 'Vaping and dental caries' and 'Data synthesis'; Table 2 (refs 15, 16, 31-37) · same question in other reviews	Narrative synthesis of 9 studies (Table 2). E-cigarette aerosol/e-liquid at higher concentrations (>=5%) and flavored liquids inhibited commensal oral streptococci and allowed S. mutans to proliferate, with increased…	9 studies	Ungraded

E-cigarette use (ENDS / vaping) vs Non-smokers

Population: Humans who use e-cigarettes (mostly adults, often with periodontal disease) assessed for oral proinflammatory markers

6 questions

Outcome	Effect	Evidence	Status / GRADE
Interleukin-8 (IL-8) Cross-sectional (single time point) for most; a few 6-month prospective · Overall (saliva + GCF) Meta-analysis suggests no significant effect of e-cigarette use on the salivary level of Interleukin-8 (IL-8) (6 studies), though heterogeneity was high (I2=84%) and the pooled estimate appears only in Figure 3C (unavailable); GCF data were limited (1 study(ies)) (ungraded). Source: Results 'IL-8'; Figure 3C; Table 3 · same question in other reviews	Cohen's d -0.43 [-1.02, 0.14]	6 studies	Ungraded
Combined salivary proinflammatory markers (IL-1β, IL-6, IL-8, TNF-α) Cross-sectional (single time point) for most; a few 6-month prospective · Saliva Combining all four salivary cytokines, the meta-analysis found no effect of e-cigarette use on salivary proinflammatory marker levels (low between-marker heterogeneity, I2=31%); the pooled estimate appears only in Figure 3F (unavailable) and is ungraded. Source: Results 'For all markers'; Figure 3F · same question in other reviews	Cohen's d 0.21 [-0.36, 0.77]	4 studies	Ungraded
Tumour necrosis factor-alpha (TNF-α) Cross-sectional (single time point) for most; a few 6-month prospective · Overall (saliva + GCF) Meta-analysis suggests no significant effect of e-cigarette use on the salivary level of Tumour necrosis factor-alpha (TNF-α) (7 studies), though heterogeneity was high (I2=95%) and the pooled estimate appears only in Figure 3E (unavailable); GCF data were limited (2 study(ies)) (ungraded). Source: Results 'TNF-α'; Figure 3E; Table 3 · same question in other reviews	Cohen's d 0.66 [-0.16, 1.43]	7 studies	Ungraded
Interleukin-1 beta (IL-1β) Cross-sectional (single time point) for most; a few 6-month prospective · Overall (saliva + GCF) Meta-analysis suggests no significant effect of e-cigarette use on the salivary level of Interleukin-1 beta (IL-1β) (11 studies), though heterogeneity was high (I2=97%) and the pooled estimate appears only in Figure 3B (unavailable); GCF data were limited (2 study(ies)) (ungraded). Source: Results 'IL-1β'; Figure 3B; Table 3 · same question in other reviews	Cohen's d 0.98 [-0.03, 1.99]	11 studies	Ungraded
Interleukin-6 (IL-6) Cross-sectional (single time point) for most; a few 6-month prospective · Overall (saliva + GCF) Meta-analysis suggests no significant effect of e-cigarette use on the salivary level of Interleukin-6 (IL-6) (6 studies), though heterogeneity was high (I2=95%) and the pooled estimate appears only in Figure 3D (unavailable); GCF data were limited (1 study(ies)) (ungraded). Source: Results 'IL-6'; Figure 3D; Table 3 · same question in other reviews	Cohen's d 0.83 [-0.16, 1.79]	6 studies	Ungraded
IL-1β level GCF Population: People who use electronic cigarettes The review reports that GCF evidence was limited and may show a potential association. Source: Results, IL-1β; Figure 3B · same question in other reviews	Cohen's d 1.58 [-0.79, 3.94]	2 studies	Ungraded