This cross-sectional study was carried out among the dental patients who reported at Government Dental College and Research Institute in Bangalore city, India, during the months of May- June 2013. Ethical clearance was obtained from the Institutional ethical committee and necessary permission was sought.

The patients who fulfilled the inclusion and exclusion criteria were recruited from the waiting areas of the respective departments.

All those patients proficient in Kannada language, who reported to the institute and provided informed consent were included.

Patients below 18 years, illiterate and who were undergoing psychiatric therapy or who reported of generalized anxiety disorders were excluded from the study.

The translation of MDAS was done by means of a forward- and back- translation procedure [6]. Two bilingual experts and one dentist translated the original MDAS from English to Kannada language. The translated Kannada versions were submitted to panel of experts who agreed on the Kannada version of MDAS. The Kannada version was then back translated to English by other set of independent bilingual experts and a dentist to check for the validation of word modification. The back translated versions were submitted to panel of experts who reached at an agreement with minor modifications. The final back-translated version was pretested and was then referred as MDAS-K

Reliability of MDAS-K was established among 30 patients who were willing to revisit the dental institute to complete the same questionnaire after a week.

Construct Validity of MDAS-K was established among 301 patients who visited the outpatient clinics of different dental departments (Orthodontia, Prosthodontia, Oral Surgery, Periodontia and Conservative & Endodontia). The psychometric questionnaire consisted of structured proforma in Kannada on socio-demographic details (age, gender, education occupation and income) and non socio demographic variables (duration of previous dental visits, past dental experiences, self perceived oral health status, avoidance of dental care due to dental anxiety).

Convergent validity was assessed using VAS. VAS from 0 (non anxious) to 100mm (extremely anxious) was used in both test – retest and in the psychometric study.

The data was analysed using SPSS-14 software (Chicago, III.USA). The internal reliability (consistency) was evaluated using Cronbach’s alpha and inter item correlation. The external reliability or test-retest reliability (stability) was evaluated using inter- item correlation matrix. Paired t-test was used to measure any difference in the mean dental anxiety scores of MDAS–K. MDAS-K dental anxiety scores during the two consecutive visits were correlated using Pearson’s correlation. The independent t-test and one-way Analyses of Variance (ANOVA) were used to study the difference in the groups based on the mean dental anxiety scores. Post-hoc Bonferroni test was done for pair wise comparison of the results which were significant. Convergent validity between MDAS and VAS was measured by using Spearman’s Correlation test. The statistical significance was set at p<0.05

The Cronbach’s alpha for MDAS-K was 0.83. The Spearman’s inter item correlation in MDAS- K showed items were homogeneous and each of them measured the same as the rest of items in the scale thus confirming the internal consistency of MDAS- K [Table/Fig-1]. The inter-item correlation matrix between the five items of MDAS -K in the two visits q1(0.84), q2(0.85), q3(0.89), q4(0.81), and q5(0.86) was significant at p < 0.01. Pearson’s correlation co-efficient between anxiety scores in the two visits of MDAS –K was 0.901 which also confirmed the stability of MDAS-K. No statistically significant difference was observed between the mean dental anxiety scores of the MDAS-K in the two visits and also between VAS test and retest [Table/Fig-2].

The construct validity was established by analyzing the socio-demographic and other non socio-demographic variables.

Patients less than 30 years of age had the highest (11.54) mean anxiety scores among the considered age groups. Statistically significant differences wereobserved between the groups (p< 0.001). Post-hoc test showed significant difference in anxiety between age group up to 30 years and those above 30 years of age [Table/Fig-3]. Pearson’s rho correlation showed inverse correlation between age and mean anxiety score and was statistically significant (r = -0.2.p< 0.01).

Statistically significant differences were observed between the genders with respect to their mean anxiety scores (p < 0.001) with mean anxiety scores of males being lower than that of females. The correlation (rpb=0.2, p< 0.0005) between the mean dental anxiety scores and the gender was statistically significant [Table/Fig-3].

The mean dental anxiety score (11.52) was found to be higher among the unemployed patients than those who were employed. One-way ANOVA showed statistically significant difference between the groups (p<0.003). The post-hoc test showed significant difference between unemployed and semi skilled workers and also between unemployed and clerical/shop owners/farmer [Table/Fig-3].

The mean dental anxiety score of the patients who had visited the dentist previously was lower (9.95) than who had not [Table/Fig-4]. The mean dental anxiety score was the highest (10.91) in patients who were not able to express their dental visit experience. However, the difference was not statistically significant [Table/Fig-4]. The mean dental anxiety score was highest (11.85) in patients who had avoided dental visits when compared to those who did not. The Independent t-test showed statistically significant difference between the groups [Table/Fig-4].

A highly significant correlation between MDAS-K and VAS in the test- retest (0.76-0.79) and Psychometric study (0.71, p< 0.001) supported the convergent validity of MDAS-K.

The highest mean dental anxiety scores were experienced by patients visiting the department of Orthodontia (11.65). The difference in the mean anxiety scores of the patients with respect to different departments was statistically significant. Bonferroni post-hoc analysis showed significant difference in mean dental anxiety scores between patients visiting departments of Orthodontia and Prosthodontia, only [Table/Fig-4].

Effect of culture on the complex network of aetiology factors is possible because the response to felt/trait anxiety depends to a large extent on processes of cognitive appraisal and coping mechanisms developed by the individual.

The reliability was established by measuring the internal consistency and the stability of MDAS-K. Cronbach’s alpha for internal consistency of MDAS-K (0.83) was similar to the Tamil version (0.83) of MDAS but higher than another Indian study by Acharya et al., [11,12]. The Cronbach’s alpha value of Greek (0.90) and Turkish (0.91)version showed a higher consistency [7,9]. The test – retest correlation of 0.9 between MDAS-K pre and post was similar to that of the Greek version (0.94) [7]. Further the test–retest inter item correlation matrix for q1(0.84), q2(0.85), q3(0.89), q4(0.81), and q5(0.86) confirmed the stability of the questionnaire and was similar to that of the Tamil version q1(0.9), q2(0.83), q3(0.89), q4(0.89) and q5(0.92) [11].

Age related cerebral changes and other factors such as acceptance of the inevitable, extinction or habituation may attenuate the fears and phobias as age advances [13]. Lindell and Locker explained that lower levels of dental anxiety in the elderly may be because problems of chronic illness and disability looms larger than oral health issues and that older patient have more time for good experiences to neutralize aversive ones [14]. In this study, age was inversely correlated to dental anxiety. The patients with less than 30 years of age had the highest mean dental anxiety scores and the difference between the groups was statistically significant. The results of the study were similar to studies of Acharya and Humphris GM [12,15] while study by Tunc suggested higher dental anxiety levels in older individuals [9]. However, no significant difference was found between age and MDAS scores by Malvani and by Gisler [16,17].

In the present study, females were more dentally anxious than males. The results of this study are in agreement with studies by Acharya and Malvania on Indian population and by Gremigni, Stabholzon European population [12,16,18,19]. This may be explained by the fact that females desire greater control but their lower perception of actual control is likely to create psychological tension [14]. Secondly, there is a general willingness among females to acknowledge feeling of dental anxiety [12].

The mean dental anxiety score was highest among less educated patients. The reason may be that education equips a person to handle stress in a better way [19]. The results are in agreement with studies conducted by Acharya and Malvania who found decreased anxiety levels with higher education levels [12,16]. However, studies by Akeel, found that people with higher level of education to be more anxious [20].

Unemployed patients were more anxious than those who were employed, the difference was statistically significant and similar to the results of the Indian studies by Appukuttan and Malvania [11,16]. This could have been due to low level of rationalization of the situation by unemployed patients [16].

There was no statistically significant difference in the mean dental anxiety scores and patients monthly family income. The results of this study are similar to the study by Hakerberg and Kanegane [21,22]. However, the results are in contrast to those of Moore wherein those having extreme anxiety were of higher income [23].

The lowest dental anxiety scores were in patients who had visited the dentist previously. However, the results were not statistically significant. Similar results have been reported in studies on Indian and Dunedin adults [16,24].

There was no statistical difference in the mean dental anxiety scores of patients with regard to their previous dental visit experience. Acharya and Malvania have reported similar results [12,16]. In a longitudinal study by Thomson and Locker, putative conditioning experience did not appear to be the main aetiological agent in the adult onset of dental anxiety [24,25]. Methodological problems remain relating to the temporal sequence of events necessary to assign a causal role. It is also possible that dentally anxious subjects may be more likely than non anxious to classify their previous experiences as negative even if they did not play an aetiological role [25].

Implications of avoidance and fear of dentistry can be a vicious cycle where fear contributes to an avoidance behaviour which in turn, leads to a deteriorating oral health that aggravates the fear [21]. In this study, patients who had avoided dental visits due to anxiety had higher mean dental anxiety scores than patients who had not (p<0.05). Appukuttam found similar results in Tamil speaking adults [11].

In this study, patients who perceived their oral health to be good had the lowest mean anxiety scores. Appukuttan found that Tamil speaking patients with high dental anxiety score expressed their oral health status as poor [11]. In a study on Israeli military personnel, those with higher dental anxiety score expressed more dental treatment needs [26]. The study by Carrillo-Díaz, established a strong correlation between self assessed oral health status and dental anxiety [27].

The highest observed dental anxiety was in patients attending the Department of Orthodontia followed by Department of Oral Surgery, Conservative dentistry, Periodontics and Prosthodontics respectively.

In a study by Weinstein patients visiting department of Oral Surgery and Orthodontia had similar mean dental scores [28]. However, the study done by Yildirim found that patients seeking restorative and prophylactic dental care had higher dental anxiety levels than those seeking Orthodontic treatment [29]. Most of the patients visiting department of Orthodontia were less than 30 years of age and had never visited a dental surgeon before. These variables could have confounded the results of this study.

Patients visiting the Department of Oral Surgery were more anxious in this study than those visiting the Department of Conservative and Periodontics while in the study by Koleoso patients felt more anxious having their tooth drilled than those who would have a local anaesthetic in their gums [30].

In this study, the patients visiting Departments of Periodontics had higher mean dental anxiety scores than those visiting the Department of Conservative and Endodontics. This was in agreement with the study by Stabholz which ranked scaling as the second most common procedure provoking dental anxiety after dental extractions [19].

Prosthodontic care evoked least anxiety in the patients and was similar to the study by Weinstein [28]. It can be assumed that dental treatment of edentulous patients is painless or without any discomfort and therefore not invoking fear. However, psychological and somatic lack of ‘well-being and also with hostility and neuroticism’s may explain the mean dental anxiety score of 8.30 in patients visiting Department of Prosthodontia [31].

The correlation between the MDAS–K and VAS established the convergent validity as observed in the study by Bahammam, Appukuttan and Facco [10,11,32].

However, this study had certain limitations since it was a self reported questionnaire based study thus recall bias could have affected the outcomes. Secondly, since it was conducted in patients visiting dental teaching institute which may not have reflected the dental anxiety levels of general population. In this study no attempt was made to distinguish between patients who visited the Department of Conservative and Endodontic surgery on the basis of restoration or endodontic procedures as most of the patients were not aware of the difference between the two.

The high reliability and validity of MDAS-K demonstrated in this study supports its cross cultural validation and indicates that it may be a valuable tool in quantifying dental anxiety among Kannada speaking adult population. The broader acceptance and adaptation of this tool in various settings by dentists can improve the quality of oral care provided to the patients, by employing cognitive behavioural or pharmacological therapy, thereby effectively dealing with their dental anxiety.