A cross-sectional observational study was carried out among the subjects attending the outpatient Department of Oral Medicine and Radiology, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India with a self-reported habit of smoking for a period of 10-30 years. The sample was randomly selected. The study was carried out for a period of six months between December 2012 to May 2013.

A total of 40 subjects within the age group of 45-60 years participated in the study. Subjects who were not associated with tobacco smoking were excluded from the current study. Subjects participating in the study were explained about the intervention to be conducted on them. The purpose of the study was explained to each participant and a written informed consent was obtained from each subject before enrolling into the study. Ethical approval was obtained from Institutional research ethical committee of Vishnu dental college, Bhimavaram, Andhra Pradesh, India.

The sample was categorised into two groups

Group 1: 20 subjects with reverse smoking habit.

Group 2: 20 subjects with conventional smoking habit.

The clinical presentation of the palatal mucosa of all the study subjects was graded according to classification given by Alvarez Gómez GJ et al., followed by correlative histocytological investigations [3].

[Table/Fig-1a-f]:

Palatal changes associated with reverse smoking.

(a) Palatal keratosis seen on palate. (b) Showing excresences on the palate.

(c) Depicting hyperpigmentation on the palate. (d) White patch seen on palate.

(e) Red areas seen on palate. (f) Depicting palatal carcinoma on the palate.

The criteria used for cytological staging [6]:

Class I (Normal): Indicates that only normal cells were observed.

Class II (Atypical): Indicates the presence of minor atypia but no evidence of malignant changes.

Class III (Indeterminate): The cells display wider atypia that may be suggestive of cancer.

Class IV (Suggestive of cancer): A few cells with malignant characteristics or many cells with borderline characteristics.

Class V (Positive for cancer): Cells that is obviously malignant.

The criteria used for dysplasia [7]:

The collected data for each subject was entered into an excel sheet and subjected to statistical analysis.

All the variables from the study were statistically analysed for the mean values, SD, standard error range, and p-value. Evaluation of results and statistical analysis was carried out using Student’s t-test, Chi-square test and Pearson correlation. In all the above tests, p-value < .05 was taken to be statistically significant, p-value >.05 was taken to be statistically not significant, and p-value < .001 was taken to be statistically highly significant. The data were analysed using SPSS.15 software.

The demographic details of the study are given in [Table/Fig-4]. No subjects were dropped out during the study both in group 1 and group 2. The mean age of subjects in group 1 is 58.65±6.92 years and group 2 is 51.40±11.32 years. When the means of both the groups were compared, significant difference was observed in reverse smokers with a p-value of 0.019 [Table /Fig-4]. The gender distribution of the subjects in group 1 shows 15 females and 5 males. Group 2 shows 20 male subjects [Table/Fig-5].

When the frequency and duration of the habits are compared between the two groups, the frequency of smoking is much higher in conventional smokers and the duration of smoking is significantly higher in reverse smoking [Table/Fig-6].

The clinical presentation of the palatal changes among group 1 and 2 subjects is depicted in [Table/Fig-7]. Majority of the subjects in group 1 were witnessed with palatal keratosis and white patch and in group 2, subjects were witnessed with nicotina palatii.

The severity of clinical changes of the palatal mucosa in both the groups is depicted in [Table/Fig 8]. In group 1, 40% of the subjects (8) have shown moderate palatal changes and In 25% of the subjects (5) mild palatal changes and 15 % of the subjects (3) severe palatal changes and 10% of the subjects (2) with palatal carcinoma. In group 2, 80% of the subjects (16) have shown mild palatal changes and the remaining subjects showed no palatal changes. The severity of clinical changes in reverse smokers had shown statistically significant results with a p-value of 0.001 when compared to conventional smokers.

Cytological staging [6] in group 1 revealed class I cytology in 35% of the subjects (7), 40% of the subjects (8) in group 2 and class II cytology in 55% of the subjects (11) in group 1, 60% of the subjects (12) in group 2. Class III cytology is observed in 10% of the subjects (2) of group 1. There is no statistical significant difference observed in cytological staging between the groups with a p-value of 0.35 [Table/Fig-9].

Histopathological grading [7] of both the groups is shown in [Table/Fig-10], where the results in both the groups tend to show mild dysplastic features in majority of the subjects. Group 1 and group 2 revealed mild dysplastic features in 35% of the subjects and 15% of the subjects in group 1 showed moderate dysplastic features and significant difference was observed between the two groups with a p-value of 0.02.

Correlation between clinical appearance and other parameters in reverse smokers showed a significant positive correlation between the clinical appearance, graded clinical changes and cytological, histological changes [Table/Fig-11]. The results support that through the clinical appearance we can judge the severity of the lesion and its histopathological and cytopathological severity.

Tobacco is consumed in a variety of different ways, though smoking is the most prevalent form of its use. Cigars deliver nicotine both through smoke and direct oral contact with wrapped tobacco [8]. Chutta is a cigar made of tobacco leaves wrapped in cylindrical shape [5]. Chutta smoking is a popular form of tobacco use which is very much prevailed among the population of coastal belt region of Andhra Pradesh, India [9]. The habit of reverse smoking by holding the glowing end of chutta [3] within the oral cavity is better described in this part of India and is practiced extensively by older women living in rural areas [9]. The present study provides new insight into the underlying mucosal (palatal mucosa) changes both macroscopically and microscopically.

As a matter of fact, the act of reverse smoking leads to diverse changes in the palatal mucosa and these are often described as “palatal changes”. These changes may exist independently or in combination with each other and pose a different clinical picture such as palatal keratosis, excresences, patches, red areas, ulcerations and pigmentation changes [Table/Fig-1,2] [5]. These lesions can be multiple and has been studied macroscopically and microscopically by Van Wyk, Schwartz, Sutherland [1,10–12].

The damaging and harmful effects of tobacco usage on oral health are well recognised and several documents have reviewed the scientific evidence relating to the oral dysplastic changes attributable to tobacco use [13].

In majority of the times, the diagnosis and grading of oral epithelium dysplasia is truly based on a combination of architectural and cytological changes [13]. Currently, the gold standard procedure to assesss oral potentially malignant and malignant lesions seems to be microscopic evaluation of Haematoxylin and Eosin stained sections for the presence of architectural and cytological changes which in general are described as epithelial dysplasia [14]. In the present study, the same aforementioned gold standard method was followed to evaluate the lesions.

In the present study mean age of subjects in group 1 showed a significant difference when compared with the group 2. This shows that reverse smoking is observed only in elder age groups [9] [Table/Fig-4].

In the present study females were predominantly involved in reverse smoking to a greater extent than males [Table/Fig-5]. There are several explanations as why reverse smoking is predominantly accustomed by females in Coastal Andhra Pradesh [15,16]. There are few taboos involved in this habit, Firstly, females started smoking in the reverse way because they wanted to keep it secret from their husbands. Secondly, the strong winds, or splashing of water during household work, increase the chances of extinguishing the chutta if it is smoked in the conventional way. Thirdly, the chuttas are smoked in the reverse way to prevent hot ashes falling on children and clothes. Fourthly, treatment for toothache where the heat generated by reverse smoking probably produces a soothing sensation and then reverse smoking may continue as a habit [2]. For conventional smoking a different pattern is observed. This habit is practised to a far greater extent among males than females.

The frequency of smoking is much higher in conventional smokers when compared to reverse smoking i.e. even with small frequency of reverse smoking it can produce wide adverse effects. The duration of smoking is significantly higher in reverse smoking than the conventional smoking as most of the population in reverse smokers belong to older age group [Table/Fig-6].

In the present study, the common palatal change observed in reverse smokers was palatal keratosis, which is in accordance with the study of Alvarez Gómez GJ et al., and Mehta FS et al., [3,17], while among conventional smokers were those of Nicotina palatine owing to the effects of tobacco on oral mucosa [Table/Fig-7].

The present study reveals clinical changes in the palatal mucosa. With respect to that, in reverse smokers, majority (40%) of the subjects showed moderate changes while in conventional smokers, majority (80%) of the subjects showed mild palatal changes respectively [Table/Fig-8]. The severity of clinical changes in reverse smokers has shown statistically significant results when compared to conventional smokers. These findings were in accordance with those of Ortiz GM et al., who reported an increased incidence of palatal changes (96.7%) in reverse smokers [18]. According to Van Der EB et al., the prevalence rate of palatal lesions was found to be 55% among reverse smokers [19].

Our results are similar to the study conducted by Ramulu et al., suggesting there is association between smoking habits and various atypical changes [1]. Per se, the reverse smoking habit leads to tremendous (atypical) changes in the glandular zones of the palatal areas. There is an appreciable difference of palatal changes both in hard palate and soft palate. Since, soft palate usually contains less number of glands and are not backed by bone, the probability of occurrence of these changes is pretty much less in this region compared to hard palate region where the changes occur at a higher rate owing to its greater number of glands and are backed by bone.

These atypical changes are of mild and severe type where the mild atypical changes of the surface epithelium usually are confined to the ducts of the glands and to the surrounding epithelium. Severe atypical changes are witnessed in the lining of the epithelium of the ducts and also to a certain extent in the surrounding epithelium on the surface. Reddy et al., reported that earliest atypical changes in the orifices of the ducts of the glands are papules and is a consequence to hyperplasia of the mucous glands [20].

In the present study, out of 20 reverse smokers 2 subjects (10%) found to have carcinomatous transformation of palatal lesion [Table/Fig-8]. This observation is in accordance with the study conducted by Ramulu et al., who reported oral cancer in 2.4 % of the patients who were presented with nicotinic stomatitis due to reverse smoking which showed atypical changes to the extent of microinvasive carcinomas histopathologically [1]. They concluded that the chemicals released during reverse smoking induces hyperplasia and hypertrophy initially both in the ductal epithelium and surface epithelium. As a consequence, the ductal lining undergoes dysplastic changes from which micro invasive carcinoma and then invasive carcinoma may arise [21].

There exists an association between reverse smoking, nicotinic stomatitis and carcinoma of the hard palate. Reddy et al., stated that reverse smoker has a relative risk of developing carcinoma of hard palate 47 times more than non smoker [22]. According to Quigley et al., the excess heat generated (120°c) during smoking and higher content of nicotine is responsible for malignant transformation in reverse smokers [23].

The habit’s characteristic approach of placing fired end into the mouth causes the heat to lie inside the mouth with the lips providing the required seal. The unheated extreme of the cigar carries the air to the zone of combustion whilst the cigar/cigarette is kept moist (through lips), increases the time of consumption from 2 to 18 minutes. As the intern temperature of the cigar is increased over 760°c consequently the intra oral temperature is Raised around 120°c. This continuous encounter (based on the frequency and duration) of palatal mucosa to extreme temperatures results in thermal injury which along with products of combustion ultimately increases the frequency of lesions when compared to conventional smoking [3]

As reported by Van Der EB et al., majority of the palatal cancer cases were observed within the reverse smokers group [19]. On comparision of cytological findings, majority of the reverse smokers and conventional smokers had witnessed class II cytology with statistically significant results [Table/Fig-9]. These findings were in accordance with the study of Mehta FS et al., [15]. The reason might be that palatal lesions occurring in highly keratinized areas of the mouth hamper the exfoliation of possible atypical cells which arise from the deeper layers of the epithelium. Thus it appears that the reliability of cytological diagnosis is inversely associated with the degree of keratinization.

On comparing the histologic findings among reverse and conventional smokers, where the results in both the groups tend to show mild dysplastic features in majority of the subjects and few subjects showed moderate dysplastic features in group 1 with a significant difference [Table/Fig-10]. The present observation was in accordance with that of Reddy et al., [18,24], Ramulu et al., [1]. The present study showed the relationship of this habit to the development of macroscopic stomatitis nicotina and to the microscopic finding of epithelial atypia and even of carcinomatous changes without macroscopic evidence of palatal changes.

A significant positive correlation between the clinical appearance, graded clinical changes and cytological, histological changes was observed in reverse smokers [Table/Fig-11]. The above findings were in accordance with the study conducted by Mehta FS et al., [15,17].

Within its limitations, the present study had extracted the possible outcomes of the effects of tobacco smoking underlying sub clinically. The possible limitations in the current study would be less sample size, the future research is directed to overcome this obstacle and entail a definite probability of sub clinical effects of tobacco smoking.

Smoking in any form, either traditionally or with a peculiar habit of reverse smoking definitely alters the oral mucosa, in particular the palatal mucosa. Prevention of tobacco use is a key element in public health. Although the literature contains description of some of the toxic effects of handling tobacco, there has been very little evidence on the consequences of smoking underlying at clinical and cellular level.

Despite the relative paucity of existing scientific data, the need to assess and evaluate the underlying consequences of tobacco smoking both macroscopically and microscopically prompted us to conduct the current study. The present study is mainly intended to evaluate the clinical palatal changes by correlating with the cytological and histopathological findings of the affected mucosa (palatal mucosa). The importance of this correlation lies in the prime detection of high risk lesions at an infant stage and therefore aiding in treatment effective procedures.

The present study evidenced significant variations between the observed clinical palatal changes with that of cytological and histopathological findings. When compared to the conventional smokers, reverse smokers present clinically with aggressive changes of the palatal mucosa, although the cytological and histopathological features may correlate.

In conclusion, even though the clinical palatal changes appears to be normal there seems to be significant changes associated with the effect of smoking when observed through cytological and histopathological procedures. So, thus the habit of tobacco smoking may significantly cause the prompt changes where the individuals are at a greater risk of developing carcinomatous changes.