The use of electronic cigarettes, or “e-cigarettes”, among youths has sparked worries about the possibility of nicotine dependence as a serious public health issue. Dental practitioners play a critical role in helping their patients quit smoking. Dental schools across the globe have policies encouraging their students to help patients quit smoking. Current research, however, indicates that a significant portion of dental students smoke combustible cigarettes and use e-cigarettes. According to studies, using e-cigarettes has resulted in the subsequent initiation of combustible cigarette smoking among its users. The aim of this study was to determine the association between the use of electronic cigarettes and the subsequent initiation of combustible cigarette smoking among dental students who were not attitudinally susceptible to smoking combustible cigarettes. A longitudinal cohort study was conducted among 121 study participants who were never combustible cigarette users and were attitudinally non-susceptible to smoking at baseline. At baseline, 66 (54.6%) study participants were categorized as e-cigarette users who were attitudinally non-susceptible to combustible cigarette smoking, and 55 (45.4%) study participants were categorized as non-users who were attitudinally non-susceptible to combustible cigarette smoking. The initiation of combustible cigarette smoking was assessed at 6- and 12-month intervals. Binomial regression analysis of the outcome at the end of one-year follow-up, when analyzed with independent variables, revealed a significant influence of e-cigarette use on taking up combustible cigarette smoking [Relative Risk: 9.395; 95% CI: 3.03–29.04]. Chi-squared analysis of independent variables revealed e-cigarette use to be significantly associated with fathers’ education level (p = 0.00), parental cigarette smoking status (p = 0.00), cigarette smoking among friends (p = 0.00), and family income (p = 0.00). E-cigarette users are more likely to believe it to be healthier (p = 0.00) than combustible smoking. In the present study, e-cigarette usage demonstrated a significant influence on taking up combustible cigarette smoking among its users. Educational institutions should implement stringent policies and regulations to prevent health professionals from using these products.