The present study aimed at evaluating the quality of life related to oral health in patients who referred to MMT centers. The findings showed that the quality of life associated with oral health was significantly lower in people who use stimulants than narcotics. Although this rate of discrepancy was not severe, a significant difference was observed between scores of the two groups of drug abusers in the areas of mental disability, mental distress, and physical disability. More specifically, the effect of oral problems caused by using stimulants was higher on dimensions of quality of life, such as distraction, stress, peace disturbance, confusion in group, life dissatisfaction, and inability to perform activities. In other words, stimulants affect mental health and quality of life related to oral health negatively. Consistent with these findings, Nazemi et al. (2019) reported that different dimensions of mental health (anxiety and social dysfunction) were significantly associated with the OHIP-14 index (22). Our findings on Fig. 1 also corroborate this point. According to Fig. 2, in addicts who use narcotics, physical disability was most associated with quality of life related to health. These results confirm the findings reported in the literature indicating that the type of substances applied affect the status of oral health indicators (23). This finding can be justified by mentioning that the most common oral lesions caused by using stimulants include dry mouth (16, 24, 25), spongy gingiva, and erythematosus with margin (16) that plays the most important role in the decline of their oral health (16). Islami et al. showed that the means of ruxism, rampant carries, xerostomia, attrition, and DMFT were higher in people with a history of using amphetamines stimulants (25). In contrast, missing teeth and caries had a significant relationship with drug abuse (26).
Generalized pigmentation was observed only in methamphetamine users. According to the literature, the duration of drug withdrawal was significantly associated with the incidence of oral lesions, so that less pigmented lesions were observed in addicts who have quit their addiction even for one month. In other words, increased duration of withdrawal improved the pink color, firmness, and stippled knife edge margin of the gum (16). Eslami et al. conducted a study in Tabriz noting that abuse of stimulants (amphetamines and methamphetamines) was higher than narcotics (opium syrup) in women (25). This pattern change can explain higher incidence of oral health-related psychological problems followed by using stimulants. In this regard, many other factors may be influential, including the effect of addiction treatment methods, such as methadone therapy and withdrawal duration (16). Lowa investigated amphetamine-dependent people and found that they intook more sugary foods, crumbs (instead of main meals), and drank cranberry drinks compared with the healthy individuals. Drug addicts believed that substance use reduced their appetite and increased their cravings for sugar (27). In the present study, only one fourth of those who referred to the substance abuse centers had been visited by dental professionals during the past year and a significant percentage of participants reported lack of a history of visits to dentists over the last three years. In Boston, about half of men and women who were addicted to drugs had more than a year since their last dental visit or were unable to recall the time of their last visit (28). According to the results of other studies, it seems that referring to dentists to receive educational and medical services is low among drug addicts around the world.
By comparing the results of this study with those reported in the literature, it can be claimed that the type of substance used by addicts is probably a more decisive factor than other personal variables in terms of the quality of life related to oral health. This finding can be justified by mentioning that quality of life related to oral health showed no significant difference not only among different levels of age, education, employment, economic status, marriage, and chronic illness, but also in other underlying factors such as a history of dental visits or the use of toothbrushes. Such discrepancy in the findings may be attributed to the sample size or the participants' characteristics since they were selected among patients who referred to MMT centers through available sampling method. Therefore, findings of the study are not generalizable to the population. In the studies by Shekarchizadeh (2013), Heidari (2019), Ahmadi (2019), Isfahani Zadeh, (2013), and Darvishpour Kakhki (2014) a significant relationship was found between the quality of health-related life and factors such as education, age, gender, and teeth condition (29, 30, 31, and 8). This finding is in contrary to the findings of the present study. Given that the participants of the above-mentioned studies included women, retired, or elderlies of different cities, differences in the results can be attributed to diversity in their nutritional, environmental, cultural, or genetic factors. However, results of the studies by Akbari (2015), Khabazian (2020), Gholami (2020), and Khatami Nasab (2020) are consistent with our findings in reporting that age and education had no relationship with quality of life related to oral health (32, 33, 34, 35). In this study, the total score of the oral health-related quality of life was 34.89 ± 6.50. Considering that these mean scores were received from the addicts who referred to addiction treatment centers, our findings cannot be representative of all addicts in Ahvaz. Moreover, substance use rates are naturally higher among the large population of addicts who are homeless and sleep on the street. As a result, future researchers are recommended to investigate addicts who are not in medical centers to provide a more comprehensive viewpoint in this area.
Limitations Of The Study
Due to the cross-sectional nature of this study, some limitations existed in reporting the definitive causal relationship between the studied variables. Furthermore, this study did not investigate addicts under treatment due to specific problems in accessing them.