|
| Author name | Type of study | Salient features of the study | Factor evaluated | Results and conclusion |
|
| Kubica et al. 2014 [13] | In vitro | Developed an analytical method for rapidly verifying sucrose and other saccharides in EC e-liquids and evaluated the sugar content in branded e-liquids | Sugars | (i) Sucrose is present in branded e-liquids |
|
| Ghazali et al. 2018 [14] | In vivo observational (case-control) study | Evaluated oral health of 120 participants, of which 40 were EC users | EC use | EC users: |
| (i) Had increased gingival bleeding |
| (ii) DMFT similar to controls |
| (iii) Relatively young |
|
| Fagan et al. 2018 [6] | In vitro | Quantified sugar levels and aldehydes in branded EC liquids, flavors, and nicotine concentrations | Sugars | Increased: |
| (i) Levels of cariogenic sugars such as glucose, fructose, and sucrose, with sucrose levels higher than fructose and glucose |
| Flavors | (ii) Aldehydes such as formaldehyde, acetaldehyde, and acrolein, with acetaldehyde being the highest |
| Nicotine | (iii) Association of formaldehyde and acrolein with fructose and sucrose |
| (iv) Sugars and aldehydes in unheated EC liquids may promote experimentation among youngsters |
|
| Huilgol et al. 2018 [15] | In vivo | Evaluated the EC use and oral health link | Frequency of EC use | (i) Daily use of ECs was independently correlated to poor oral health |
|
| Ghazali et al. 2019 [16] | In vivo observational (case-control) study | Compared the caries occurrence between the noncigarette and non-EC users, cigarette users, and EC users | EC use | (i) No significant difference in the mean DMFT values between all groups at baseline and 6 months |
|
| Nelson et al. 2019 [17] | In vitro | Evaluated the flavorless EC aerosol influence on the planktonic growth of oral commensal such as streptococci and compared the outcomes with those of CC smoke | EC aerosol | (i) E-liquid and aerosol sparsely affected streptococcal growth, while CC smoke hindered streptococcal growth |
| (ii) Smoke-treated growth media was more detrimental to oral commensal streptococci than e-liquid or EC aerosol |
|
| Kim et al. 2020 [4] | In vitro | Evaluated the cariogenic potential of EC aerosols generated from e-liquids with sweet flavors | EC aerosol flavor | (i) EC aerosols enhanced microbial adhesion to enamel, specifically the S. mutans, due to their viscosity, doubled biofilm formation, and reduced enamel hardness |
| (ii) Esters in e-liquid promoted enamel demineralization |
| (iii) Sugar alcohols inhibited S mutans growth and adhesion |
| (iv) The EC aerosol’s physiochemical properties were similar to high-sucrose, gelatinous candies, and acidic drinks. Viscous e-liquids, together with the chemicals in sweet flavors, increased the cariogenic potential of EC’s |
|
| Fischman et al. 2020 [18] | In vitro | Tested the influence of popular e-liquid flavorings on the planktonic growth of oral commensals such as streptococci | E-liquid flavor | Flavored E-liquids: |
| (i) More unfavorable for oral commensal bacterial growth than unflavored e-liquids |
| (ii) Disturb the composition and growth of primary colonizers hindering healthy dental plaque and host-bacteria interactions |
| (iii) Alterations in the pioneering oral communities may be harmful to oral health |
|
| Rouabhia and Semlali 2021 [19] | In vitro | Evaluated the effects of ECs on S. mutans growth, biofilm formation, and virulence genes expression | EC aerosol | (i) Promoted S. mutans growth at the early culture period |
| (ii) ECs increased S. mutans growth and virulent gene expression |
| (iii) ECs increased adhesion and biofilm formation on teeth surfaces |
|
| Vemulapalli et al. 2021 [7] | In vivo observational (cross-sectional) study | Evaluated the link between vaping and untreated caries at the population level | | (i) Higher levels of untreated caries in only EC smokers and dual smokers (EC + CCs) |
|
| Xu et al. 2022 [3] | In vitro | Evaluated the influence of flavors in e-liquids on single and multispecies biofilm formation, growth, and the inhibition mechanism | E-liquid flavor | Flavors: |
| (i) Inhibit single-species and multispecies biofilms dose-dependently |
| (ii) Produce bactericidal effect on the oral streptococci, inhibit oral commensal bacteria biofilm formation and growth, and negatively influence the oral microenvironment |
|
| Catala-Valentin et al. 2022 [20] | In vitro | Explored the influence of ECs on oral bacteria | EC aerosol | (i) EC aerosols disturb oral bacterial homeostasis by hindering commensal growth and promoting biofilm formation by the opportunistic pathogen S. mutans |
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