Oral health neglect is a common feature of PS abuse.[2,3] Alcohol has been thought to influence DC via the microbial oxidation of ethanol in saliva in alcohol abusers resulting in the formation of acetaldehyde that inhibits the cariogenic oral flora. Alcohol enhances fluoride release from certain restorative materials.[4] Nicotine, a major constituent of tobacco, is known to limit the proliferation of Streptococcus viridians.[5] On the contrary, sugar-laced chewing tobacco extracts have been shown by in vitro evidence for stimulated growth of S. mutans and S. sanguis.[6]

It is considered that frequent chewing of areca nut confers a protection against DC. Areca nut by itself lacks ingredients that have cariostatic properties. The extrinsic stain formed by the chronic habit acts as a laminate preventing adherence and colonization of the cariogenic microbes. The gritty consistency of the areca nut mediates a mechanical cleansing activity eliminating the food debris.[7] Repeated chewing stimulus results in an increased salivary flow rate that also aids in the removal of organisms and food debris. The tannins in this bolus have antimicrobial properties. Attrition in chewers makes the teeth surface smooth and reduces the risk of pit and fissure caries. The sclerosis of dentin by repeated masticatory trauma renders the dentin resistant to the microbial invasion.[7] The addition of lime alters the pH of the oral cavity making it unsuitable for the cariogenic organisms to survive.[8] Moreover, the salivary flow rate and pH have been shown to vary with the type of areca nut and tobacco chewed.[9]

Trained physicians and dental surgeons calibrated and examined the patients. Their clinical findings were recorded in a predetermined format, which included detailed recording of the patients’ habits (alcohol and tobacco (with/without areca nut)) as per earlier published protocols and clinical observations including Oral Hygiene Index-Simplified (OHI-S) and Dental Caries, Missing, Filled Tooth (DMFT) index.[1] Tobacco use was measured as pack (ten’s) years. Smoking tobacco pack years were calculated as published in the literature and smokeless tobacco (2 gm per pack) used per year as pack years.

Only dentate subjects were enrolled for the study. Based on their PS habits, the study group was broadly divided into four groups without any overlap. They were alcohol-only abusers (A), alcohol and smoking tobacco abusers (AS), alcohol and chewing tobacco abusers (AC) and smoking, chewing tobacco with alcohol abusers (ASC). Presence of attrition and extrinsic stain (< two-thirds of any surface in any teeth) were noted. Occasional tobacco users were excluded. For the present study, tobacco use was considered as abuse when the subject used any form and quantity of tobacco continuously for three months. Alcohol abuse was considered as per standard definitions.[1]

Across study groups, prevalence of at least one DC was not statistically significant (P=0.113), while at least one missing tooth (P=0.000) was significant. The mean difference in DMFT, OHI-S, DC, missing and filled teeth across study groups was significant. Mean years of alcohol abuse and units of alcohol consumed per week were significantly different across the study groups (P =0.001 and 0.000 respectively).

Figure 1 depicts the type of alcohol used by the study group. Table 2 depicts the oral hygiene measures adopted by the study population and was not significantly different across groups. Outcome of oral hygiene measures was measured as caries experience. Material and methods used for oral hygiene were significantly associated with OHI-S and DMFT as well as missing teeth [Table 3].

Bivariate logistic regression between DMFT greater than or equal to 1 and 0, revealed that marital status (OR 1.217, 95%CI- 0.95 – 1.560, P = 0.122), religion (OR 1.03; 95%CI 0.84 – 1.25, P = 0.797), education (OR 1.03; 95%CI – 0.93 – 1.15; P = 0.54) were not significant while age group (OR 1.07; 95%CI – 1.01 – 1.13; P = 0.02) and occupation (OR 1.04; 95%CI 1.008 – 1.066; P = 0.011) were significant. On further analysis of age group and occupation, none of the individual subgroups had ORs that were statistically significant.

Similarly, for DC greater than or equal to 1 and 0, bivariate logistic regression revealed that marital status (OR 1.032, 95%CI- 0.827 – 1.289, P = 0.778), occupation groups (OR 1.023; 95%CI 0.998 – 1.049; P = 0.075), religion (OR 1.039; 95%CI 0.865 – 1.247, P = 0.686), education (OR 1.012; 95%CI – 0.919 – 1.114; P = 0.81) were insignificant while age group (OR 0.924; 95%CI – 0.879 – 0.971; P = 0.002) was significant. On further analysis of age group, none of the individual subgroups had statistically significant OR.

There was a statistical significance between the prevalence of DMFT, missing teeth and filled teeth between chewers and non-chewers while filled teeth was only significant between those with and without pouching habit [Figure 2]. There was a statistically significant difference in the caries experience between those with and without attrition with a P value of 0.021 [Table 4]. The mean DC in patients having attrition was 1.56 while for patients with no attrition it was 2.05.

Table 5 depicts the results of one-way ANOVA for DMFT, DC, missing and filled teeth. The means of filled and dental caries-affected teeth were significantly different across the group. Pack years did not influence the DMFT scores.

Reports of DC among PS users from various parts of the globe have been documented. In a survey of hospitalized alcoholic patients in Wyoming, USA, alcohol abusers had a three times higher permanent tooth loss than the USA’s national average for corresponding ages.[11] A smaller group of alcoholics in Maryland, USA also had a higher number of missing teeth.[12] In a case-control study of 85 volunteer Finnish alcoholics, there were significantly fewer teeth and more remaining teeth with DC.[13] Use of tobacco and or areca nut[7,8] in various forms and its interaction is known to cause abnormality in salivary pH, flow rate[8] as well as the oral micro-flora[5,6] thereby influencing the initiation and progression of DC. Mean age, DC, DC point prevalence and DMFT in the entire study population was 38.49 years, 2.02±2.6, 58.6% and 3.49±3.93 respectively. These values are comparatively higher than the Indian national average of DC - 42.24% and DMFT of 1.39. This indicates that PS use has a larger role to play in poor oral health. This has been in accordance with previous reports such as those of Dasanayake et al., from London.[4] In our earlier reports from this part of India, PS use has been documented to have DC experience varying with various type of PS. However, the DC experience has not been studied in detail in those reports.[1–3]

In the present study, there was a significant statistical difference when the mean remaining teeth, DC, filled teeth and DMFT were compared across the various types of PS abuse [Table 1]. This indicates that the type of PS abused would probably influence the DC experience and oral hygiene status. About 95% of all subjects in each study group used toothpaste, more than 80% of them brushed once a day and more than 97% used a toothbrush to maintain oral hygiene. The oral hygiene measures were not significantly different between the study groups. On the contrary, the type of PS abuse differed with respect to current DMFT status. The brushing material (toothpaste/toothpowder/others) used and mode of oral hygiene care (toothbrush/fingers/others) had a significant difference in terms of current DMFT and OHI-S scores. This finding also explains that the type of PS would probably be a major factor in determining the DC, DMFT as well as OHI-S. As Table 2 indicates, the method of oral hygiene care used by the subjects in the present study, did not significantly differ among study groups indicating that the PS abused is an important factor that differed in the study population. Though tobacco abuse was prevalent for longer periods among the study groups, as indicated by the higher mean duration, it was not contributory.

Tobacco usage in any form immediately increases salivary flow, but the effect of long-term use is poorly understood. The pH of saliva tends to rise during smoking tobacco, which in the long term reduces marginally. There are reports of increasing concentration of thiocynate in saliva, probably from the smoked form of tobacco.[14] Lower cystatin activities have been reported in tobacco smokers. Cystatins are believed to contribute to balanced oral health by inhibiting certain proteolytic enzymes.[15] There have been contradictory reports of DC in tobacco smokers. A few studies show a higher incidence of DC in smokers[16] while some show decreased activity of Streptococci and other oral commensals[5] and other studies failed to show any differences.[15] Our study is in concurrence with previous findings of increased incidence of DC among smokers.[4,17]

Offenbacher and Weathers[18] reported on the dental effects of smokeless tobacco use among school-aged males from Georgia. In their study, DMFT scores for smokeless tobacco users with gingivitis were higher than for those who did not use smokeless tobacco and did not have gingivitis. From their findings they concluded that the presence of gingivitis was an indicator of oral hygiene and that poor oral hygiene was a cofactor with smokeless tobacco use in the development of dental caries.[18] However, the smokeless tobacco in Western countries[19] and several areca nut preparations in India[17] contained varying amount of sugars which could be responsible for root caries rather than coronal caries as well as an increased amount of gingival recession in smokeless tobacco users.[19] In the present study, the increased incidence of DC in the groups that used tobacco, chewing (2.18), smoking (2.06) or both (1.91) in addition to alcohol as compared to the alcohol-only usage group (1.72), experienced higher DC. This finding supports the fact that tobacco in any form increases the risk of DC.

As indicated in Tables ​Tables1,1, ​,5,5, the higher incidence of missing teeth due to DC, particularly in alcoholic smokers is another indicator of the synergistic effect of tobacco use and poor oral hygiene that has been reported earlier.[17] Analysis of chewing and pouching habits [Table 4] confirm the fact that smokeless tobacco with/without areca nut when chewed causes less DC than when pouched. These findings were in agreement with the reports of Moller et al.[7] Similarly, in those cases who had attrition, prevalence of DC was lower. This could be due to the fact that attrition could lower the grooves and pits, which probably play a major role in the initiation of DC.[7]

As observed in Table 4, DMFT between those with significant extrinsic stain and without it were not significantly different while the incidence of DC classified on the presence and absence of attrition had a statistically significant difference. These findings reiterate the fact that chewing forms could cause attrition, and DC in such situations are less. Moreover, extrinsic stains could act as a protective laminated covering and aid in prevention of DC.[7,8] In the present study, the difference between the incidence of DMFT score and missing teeth was significantly higher in subjects with > two-thirds of surface with extrinsic stains than with others [Table 4].

The interaction of oral flora with PS abuse has not been reported in the literature to the best of our knowledge. However, a smaller sample size has been used to report the changes in oral microflora with PS use, especially use of chewing tobacco.[20] It has been showed that use of chewing tobacco decreased the colony-forming units’ count of Lactobacillus, Prevotella and Porphyromonas species and increased Fusobacterium species.[20] In our study, the mean dental caries experience among the types of PS abuse, significantly different, in terms of caries experience, could have probably been due to the postulated decrease in the normal oral microbial flora as a result of PS use.