Submitted: 06 Dec 2017
Revised: 25 Jan 2018
Accepted: 28 Jan 2018
First published online: 18 Apr 2018
EndNote EndNote

(Enw Format - Win & Mac)

BibTeX BibTeX

(Bib Format - Win & Mac)

Bookends Bookends

(Ris Format - Mac only)

EasyBib EasyBib

(Ris Format - Win & Mac)

Medlars Medlars

(Txt Format - Win & Mac)

Mendeley Web Mendeley Web
Mendeley Mendeley

(Ris Format - Win & Mac)

Papers Papers

(Ris Format - Win & Mac)

ProCite ProCite

(Ris Format - Win & Mac)

Reference Manager Reference Manager

(Ris Format - Win only)

Refworks Refworks

(Refworks Format - Win & Mac)

Zotero Zotero

(Ris Format - FireFox Plugin)

Abstract View: 875
PDF Download: 584
Full Text View: 393
CC-BY © 2018 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided theoriginal work is properly cited.
Cross-Cultural adaption, validity and reliability of a Hindi version of the Corah’s Dental Anxiety Scale

Health Promotion Perspectives, 8(2), 120-126; DOI:10.15171/hpp.2018.15

Original Article

Cross-Cultural adaption, validity and reliability of a Hindi version of the Corah’s Dental Anxiety Scale

Meena Jain1 ,*, Shourya Tandon2, Ankur Sharma1, Vishal Jain3, Nisha Rani Yadav1

1 Manav Rachna Dental College, Faridabad, Haryana, India
2 Faculty of Dental Sciences, SGT University, Gurugram, Haryana, India
3 Institute of Dental Studies and Technologies, Modinagar, UP, India

Email: drmeenabansal@gmail.com

© 2018 The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background: An appropriate scale to assess the dental anxiety of Hindi speaking population is lacking. This study, therefore, aims to evaluate the psychometric properties of Hindi version of one of the oldest dental anxiety scale, Corah’s Dental Anxiety Scale (CDAS) in Hindi speaking Indian adults.Methods: A total of 348 subjects from the outpatient department of a dental hospital in Indiaparticipated in this cross-sectional study. The scale was cross-culturally adapted by forward and backward translation, committee review and pretesting method. The construct validity of the translated scale was explored with exploratory factor analysis. The correlation of the Hindi version of CDAS with visual analogue scale (VAS) was used to measure the convergent validity.Reliability was assessed through calculations of Cronbach’s alpha and intra class correlation 48 forms were completed for test-retest.Results: Prevalence of dental anxiety in the sample within the age range of 18-80 years was 85.63% [95% CI: 0.815-0.891]. The response rate was 100 %. Kaiser-Meyer-Olkin (KMO) test value was 0.776. After factor analysis, a single factor (dental anxiety) was obtained with 4 items.The single factor model explained 61% variance. Pearson correlation coefficient between CDASand VAS was 0.494. Test-retest showed the Cronbach’s alpha value of 0.814. The test-retest intraclass correlation coefficient of the total CDAS score was 0.881 [95% CI: 0.318-0.554].Conclusion: Hindi version of CDAS is a valid and reliable scale to assess dental anxiety in Hindi speaking population. Convergent validity is well recognized but discriminant validity is limited and requires further study.

Keywords: Dental anxiety, Psychometric, Questionnaires, Reliability, Validity

Citation: Jain M, Tandon S, Sharma A, Jain V, Yadav NR. Cross-cultural adaption, validity and reliability of a Hindi version of the Corah’s Dental Anxiety Scale. Health Promot Perspect. 2018;8(2):120-126. doi: 10.15171/hpp.2018.15.


Dental anxiety is defined as “a patient’s response to stress that is specific to dental situations”.1 It is one of the highly prevalent2-4and lesser studied problems5associated with dental treatment. Dental anxiety is known to be associated with various dental and general healthcare problems, such as poor quality of life,6 abstinence from, or avoidance of dental treatment,7-9 as well as lack of sleep.10

Generally, dental treatment is related to psychological and physical discomfort. A high percentage of anxious patients are so fearful that they avoid the dental treatment, cancel or delay the appointment, and become less cooperative during dental treatments. Patients may also have a low pain threshold attributable to dental anxiety.11 In addition to this avoidance behavior, dental anxiety also has a wide-ranging and dynamic impact on various aspects of a patient’s life.12,13 Therefore, an estimation of patient’s anxiety is an important step towards a safe and quality dental care.

Dental anxiety is usually measured using a wide range of available psychometric self-assessment scales such as Corah’s Dental Anxiety Scale (CDAS),14 Modified Dental Anxiety Scale (MDAS),15 State-Trait Anxiety Scale (STAI),16 General Geer Fear Scale,17 Getz Dental Belief Survey,18 Chotta Bheem-Chutki Scale19 and Dental Fear Survey (DFS).20 These scales range from 1 item to 20 items or even more. Different scales are based on different theoretical models and they measure dental anxiety from different perspectives.21

The CDAS is a 4-item, self-reported measure that asks the participants to rate the anticipated level of anxiety, a day before the visit to the dentist, while sitting in the dentist’s waiting area, when the dentist is preparing the drill, and before scaling of teeth.14 In the MDAS, the fifth question concerning local anesthesia injection for dental treatment has been added to CDAS.15 However, anxiety over anesthesia may not be directly associated with dental treatment anxiety but could be associated with the use of needles in general. Moreover, not all dental treatments require anesthesia. Therefore, MDAS can overestimate dental anxiety.22 Also, the CDAS is probably the oldest and most widely used scale.22The psychometric properties of this scale have been determined in English,15 Chinese,23 Portugese24 and Italian language.25 CDAS was also found valid and reliable in a sample of Brazilian adults.22

However, translation and validation of this scale have not yet been done for Hindi. According to the Official Languages Act, 1963, Hindi has been adopted as the official language of the Union of India. It is also the largest spoken and understood language by citizens of India, especially of North India. Apart from India, the language is also spoken in many other countries like Nepal, Guyana, Trinidad and Tobago, Suriname, Fiji, and Mauritius. This study was, therefore, conducted to develop and evaluate the validity and reliability of the Hindi version of CDAS when applied to a sample of Hindi speaking adults in India.

Materials and Methods

The psychometric properties of Hindi version of CDAS were studied through a cross-sectional study, approved by the Institutional Ethics Committee of the institution. The study was conducted from May to June 2017.

The instrument (CDAS) was translated and cross-culturally adapted26in Hindi at an institute of higher dental education in the National Capital Region of India. A “forward and backward blind translation” process was used. Two bilingual professionals who were fluent both in English and Hindi did the forward translation of scale from English to Hindi. These 2 Hindi versions were then again translated into English by 2 other translators, who were not aware of the original English CDAS questionnaire. These back-translated versions were committee reviewed by the authors along with four translators. They reviewed the translations for a comprehensive and semantic equivalence till the Hindi version was considered appropriate by all of them.

This translated version was pretested on the Hindi-speaking population. Twenty subjects from the outpatient department of the dental hospital were selected to fill in the questionnaire. The subjects were then interviewed to find out whether, they understood the translated questions. They were asked to mention if any question or word was difficult to understand. All corrections were discussed among the authors, and appropriate changes were made in the translated Hindi version. The final version was designated as CDAS-H.

A study sample was drawn from the population of patients visiting the outpatient department of the institute. The sample consisted of the patients who visited the dentist earlier, as well as the first time visitors. It included the individuals who consented to participate in the study and who were 18 years or above. Individuals who had either learning, audio-visual, psychiatric or intellectual disability or disorder, as well as those who were unable to read or understand Hindi language were excluded from the study. Validation was done among 348 participants who were selected from the patients attending the Outpatient department (OPD) on the days of study.

The study instrument was the final Hindi version of the 4 item CDAS. The scale measures the perceived dental anxiety of the patients. The respondents filled the self-report questionnaire according to the 5-point Likert scale that ranged from ‘not anxious’ to ‘extremely anxious’. The response was scored from 1 to 5. The scores for all the responses were added to obtain the level of dental anxiety for the participant. The total scores of CDAS for an individual varied from 1 to 20. Basic demographic data like age, gender and education were obtained along with the study instrument.2,3,4,23,25,27 Additionally, information such as self-perceived oral health status, previous visit to the dentist and their experience of the visit were also obtained. Apart from the CDAS, a visual analogue scale27 (VAS) was also recorded to measure the convergent validity. VAS was taken because no other standard scale to measure dental anxiety has been validated in the Hindi language. VAS has been used in studies for measuring dental anxiety28and was found to be valid.29 This was obtained on a scale from 0 to 100 calibrated over a 100 mm line where zero refers to “not at all anxious” and 100 refers to “extreme dental anxiety”. The participant was told to mark a point for the anxiety he felt towards dental treatment. VAS score was assessed by calculating the distance in mm from the left end of the line to the spot where the participant had marked.

Data were analyzed through IBM SPSSTM Statistics for Windows, version 20.0 (IBM Inc., Armonk, NY, USA). Reliability was investigated by calculating Cronbach’s alpha and intra class correlation (95% CI). Sampling adequacy was measured using Kaiser-Meyer-Olkin (KMO) test. Principal Component analysis with Varimax rotation was performed to examine the construct validity and to compare the factorial structure of the Hindi version of CDAS with the original version. Study variables were correlated using Pearson correlation to establish convergent validity. The differences in groups were calculated using independent t test (two-tailed) and one-way analysis of variance (ANOVA). Skewness and kurtosis value less than 3 and 7 respectively are considered non-significant deviations from normality and acceptable sensitivity.30All the statistics were considered significant at a P value of equal to or less than 0.05.


Descriptive statistics

The response rate was 100% as the forms were duly filled. Forty-eight forms that were completely filled for test-retest also had 100% response rate. Male participants in the study were 53%. Table 1 presents the categorization of participants according to their total CDAS score. The prevalence of dental anxiety was 85.63% (95% CI: 0.815-0.891). Around 8% of participants experienced extreme anxiety. The mean CDAS score was 8.73 (SD: 3.55), and the mean VAS score was 52.49 ± (SD: 24.70). None of the participants had CDAS total mean score of 0 or 20.

Table 1. Categorization of patients based on CDAS scores
CDAS score range No. (%) Mean CDAS score
0-4 (not anxious) 50 (14.37) 4
5-8 (low anxiety) 131 (37.64) 6.54 ± 1.10
9-12 (moderate anxiety) 109 (31.32) 10.49 ± 1.12
13-14 (high anxiety) 30 (8.62) 13.33 ± 0.48
15-20 (extreme anxiety/phobic) 28 (8.05) 15.68 ± 0.61
Total 348 (100) 8.73 ± 3.55

In the present study, the values of skewness and kurtosis for age, CDAS score, and VAS score were found to be within normal limits. Hence, these values reflect no significant deviation from normality. The age of participants ranged from 18 to 80 years with the mean of 29.98 ± (SD 11.90). Table 2 shows the descriptive statistics of variables evaluated in this study.

Table 2. The variables with the percentages, mean total score and statistical test
Variable No. of samples Percent Mean total CDAS score ± (SD) P value
Age group >0.05
≤30 231 66.38 8.70 ±(3.55)
31-50 91 26.15 8.87 ±(3.57)
≥51 26 7.47 8.54 ±(3.59)
Gender >0.05
Male 185 53.2 8.85 ±(3.55)
Female 163 46.8 8.60 ±(3.56)
Education >0.05
Primary level 57 16.4 9.49 ±(3.59)
Senior Secondary level 65 18.7 8.03 ±(3.56)
Degree/Diploma 200 57.5 8.69 ±(3.55)
Post-graduation 26 7.5 9.23 ±(3.58)
Oral Health <0.001
Excellent 57 16.4 7.43 ±(3.56)
Good 163 46.8 8.68 ±(3.55)
Average 101 29 9.03 ±(3.57)
Poor 27 7.8 10.67 ±(3.79)
Visited earlier to dentist <0.05
Yes 220 63.2 8.43 ±(3.55)
No 128 36.8 9.25 ±(3.57)
Previous dental experience <0.001
Good 183 83.2 7.87 ±(3.55)
Bad 37 16.8 11.22 ±(3.56)

Validity measures

A positive correlation was observed among four items of CDAS questionnaire in correlation matrix. Bartlett’s test of sphericity was found statistically significant (χ2 = 378.747, P < 0.0001). The KMO test value was found to be 0.776 which is acceptable to perform factor analysis. Eigen value for the single factor (dental anxiety) was 2.441 which demonstrated 61% of the variance (Table 3).

Table 3. Exploratory factor analysis with rotation
Component Initial Eigen value Percentage of variance Percentage
1 Total= 2.441 61.019 61.019
Items Matrix of the factorial structure Total Communalities
Q1 0.755 0.570
Q2 0.796 0.634
Q3 0.789 0.623
Q4 0.783 0.614
Extraction method- Principal Component Analysis with Varimax rotation

Discriminant Validity


CDAS total mean score of participants of age ≤30 years, 31-50, and ≥51 was 8.70, 8.87, and 8.54 respectively. One-way ANOVA showed that this difference was not significant statistically (F value: 0.113) (Table 2). Also, very weak correlation was found between age and CDAS total mean score, which was statistically not significant (r= -0.002, P > 0.05).


Mean score of CDAS for males was 8.85 whereas it was 8.60 for females but the difference was not statistically significant (Table 2). Kendall’s Tau Correlation Analysis showed no significant relation of gender with CDAS total score (r = -0.027, P > 0.05).


The CDAS total mean scores according to the level of education are presented in Table 2. Participants with primary level of education had highest mean CDAS score. But one-way ANOVA showed that the difference in scores was not statistically significant (F value: 1.947).

Dental attendance

The mean CDAS score of patients who had earlier visited a dentist was 8.43 whereas for those who had not visited any dentist was 9.25 and the difference was statistically significant (t test: 2.081). From the 220 participants who had visited a dentist earlier, 183 had a good experience with the mean CDAS score of 7.87 which is less than CDAS score 11.22 of those who had a bad experience during their dental visits. The difference was statistically significant (t test: 5.691) (Table 2).

Oral Health

CDAS total mean score was highest (10.67) for the participants who had a poor self-perceived oral health status. These scores decreased as the self-perceived oral health status improved. One-way ANOVA showed that this difference was highly significant statistically (F: value 5.653, P < 0.001) (Table 2).

Convergent validity

Pearson correlation coefficient was calculated to assess the convergent validity of the Hindi version of CDAS. Pearson correlation coefficient of the individual items CDAS 1, CDAS 2, CDAS 3, and CDAS 4 with VAS score was 0.327, 0.352, 0.407, and 0.466 respectively. CDAS and VAS scores had a highly significant correlation (r = 0.494, P <0.001), indicative of a fairly positive correlation.

Reliability measures

The inter-item correlations among 4 items in consecutive visits among 48 participants were to be found positive. Cronbach’s alpha for the test-retest was 0.814. Correlation among 4 CDAS items in first and second visit using Pearson correlation was 0.733, 0.737, 0.570, and 0.493 for CDAS 1, CDAS 2, CDAS 3, and CDAS 4, respectively (P <0.001). A positive correlation was observed among 4 items in the sample of 348. The Intra-class correlation coefficient between four items was 0.425 (95% CI: 0.318-0.554, F test: 8.397, P<0.001). Cronbach’s alpha for 348 study subjects was 0.782. Table 4 also details the inter-item statistics which showed that all the four items contributed significantly and the internal consistency of the CDAS scale is acceptable.

Table 4. Item-total statistics
Scale mean if item deleted Scale variance if item deleted Corrected item-total correlation Cronbach's alpha if item deleted
Q1 6.57 7.012 0.562 0.750
Q 2 6.66 7.850 0.615 0.717
Q 3 6.55 7.931 0.598 0.725
Q 4 6.41 7.673 0.593 0.726

Table 5 presents the intra-class correlation coefficient values for test-retest of 4 individual items refilled by 48 study subjects after 15 days. The test-retest ICC of the total CDAS score was 0.881 (95% CI: 0.318-0.554) with a P value <0.001 indicative of an excellent agreement.

Table 5. . Intra-class correlation coefficient (ICC) values for test-retest reliability of the 5 items and total score of Hindi version of CDAS
DAS ICC 95% CI F test P value
Lower Upper
CDAS 1 0.839 0.713 0.910 6.206 <0.001
CDAS2 0.842 0.719 0.912 6.337 <0.001
CDAS 3 0.726 0.511 0.846 6.486 <0.001
CDAS 4 0.660 0.393 0.809 2.938 <0.001
Total CDAS 0.881 0.824 0.925 8.397 <0.001


It is vital for a dentist to assess the dental anxiety levels of a patient so as to provide a good dental experience. It is also suggested to assess dental anxiety before preventive programs for better patient participation in oral hygiene maintenance. A valid and reliable scale to evaluate the dental anxiety of Hindi speaking Indian population was lacking. Hence, this hospital-based cross-sectional study was conducted in India to develop an appropriate Hindi version of CDAS and to evaluate the psychometric properties of the translated instrument. The present study results showed that the CDAS-H has good psychometric properties. The convergent validity (Pearson correlation coefficient = 0.494) was good. In this study, factor analysis resulted in loading on one factor which was consistent with observations from studies in Portuguese24 and Brazilian22 populations.

Cronbach’s alpha value of Hindi CDAS in the present study was 0.78 which is good and acceptable. The value of Cronbach’s alpha for adults from Brazilian population was 0.83,22 from Portuguese population was 0.838,24 for Italian population was 0.88325 and from English population, it ranged from 0.75 to 0.92 in various subgroups.15 The items fitted well with each other on the scale because the corrected item-total correlation coefficients of all 4 items were above 0.4.31 Also, CDAS-H has excellent test-retest reliability (ICC = 0.881). The 100% response rate for this questionnaire also indicates that a nominal supervision is required for measuring dental anxiety using CDAS-H. Also, the floor and ceiling effect for CDAS-H was not present.

In the present study, 8% of the participants had extreme dental anxiety. This was higher as compared to other studies done in Indian population by Acharya32(2.2%), Appukuttan et al2,3(3%), Appukuttan et al33(2.7%) and Marya et al34(4.4%). However, the percentage was lesser than in studies conducted in other countries like USA4 (20%), Bulgaria35 (11.7%), UK36 (11%), Turkey37 (23.5%) and Iran38 (12.5%). This may be due to difference in cultures and ethnicity of various study populations.

The present study showed no relation between age and mean dental anxiety score which was similar to the study done in Gujrati,39 Portuguese24and Iranian38 populations. However, the studies in Indian population by Acharya,32 Appukuttan et al2,3,33 and Marya et al34 showed that dental anxiety reduced as the age increased. Further, studies from other countries like China,23 USA4and Bulgaria35 also showed an inverse relation between age and dental anxiety level. However, Tunc et al37 showed a positive relation between age and dental anxiety. Therefore, the association between age and dental anxiety is not clear.

Most of the studies showed that females have higher mean dental anxiety scores as compared to males.37-39, It is believed that females acknowledge their anxiety more easily compared to their male counterparts.27 However, the present study showed that dental anxiety scores are independent of gender and the result was similar to the studies in Nepali31and in Portuguese24 populations. There was no significant effect of education on dental anxiety levels in the present study sample and this result is consistent with the study in Portuguese24population.

In this study, the self-perceived oral health status was inversely related to mean CDAS scores. The results were similar to study by Appukuttan et al.33 Participants with good previous dental experience had lesser mean dental anxiety scores in comparison to patients with a bad previous experience at a dental visit and this result was similar to the study conducted by Acharya.32

Several studies have shown a positive relationship of dental anxiety with general anxiety and depression.40,41 An association has been found between psychological status and dental anxiety.42 Patients with dental anxiety can have some underlying psychological distress which needs to be addressed. In patients with extreme dental anxiety, therefore, a dentist should motivate the patient to consult mental care professionals.41 CDAS-H is helpful for both dental and mental health professionals to assess dental anxiety during treatment.

Both, a good sample size of 348 subjects and a wide range of age group of participant’s increases the generalizability of results from the present study. The limitation of this study was that it used a self-reported questionnaire; therefore, dental anxiety levels in uneducated population could not be studied. Secondly, being a hospital-based study; it could have underestimated the prevalence of dental anxiety and percentage of extremely anxious subjects. Thirdly, criteria validity could not be established due to the absence of standard scales to measure dental anxiety/fear in Hindi language. Fourthly, a confirmatory factor analysis in a larger sample is warranted. Despite the fact, this study has made novel efforts in cross-cultural reliability and validity of CDAS-H.


The CDAS-H showed acceptable levels of reliability and validity. Convergent validity was well established as VAS correlated significantly with total CDAS score as well as with each item of CDAS individually. However, discriminant validity requires further studies as factors influencing or determining dental anxiety are still not established in Hindi speaking population. Also, not many studies have measured dental anxiety in Hindi speaking population. Epidemiological studies using CDAS-H are required to assess dental anxiety at the state or national level. CDAS-H can be utilized for research purposes as well as for individual patients in the dental office for those having Hindi as their first language. Further, it is recommended to translate and validate CDAS in various other languages for use in populations with different cultures and languages.

Ethical approval

Ethical approval to conduct the study was taken from the Institutional Ethics Committee, Manav Rachna Dental College, Faridabad, Haryana, India, with letter reference number MRDC/IEC/2017.280.

Competing interests

The authors declare that there is no conflict of interest.

Authors’ contributions

MJ involved in the conception and designing the study, data interpretation, wrote manuscript and acted as corresponding author. ST involved in the conception and designing the study, supervised the development of work, evaluated and edited the manuscript. AS performed the translation of instrument, data analysis and interpretation, evaluated and edited the manuscript. VJ involved in the conception and designing the study, data analysis, helped in writing the manuscript, evaluated and edited the manuscript. NRY performed the translation of instrument, helped in data collection, to evaluate and edit the manuscript.


The authors wish to express their sincere gratitude to all those who motivated and helped them in conducting this study.


  1. Corah NL, Gale EN, Illig SJ. Assessment of a dental anxiety scale. J Am Dent Assoc 1978;97(5):816-9.
  2. Appukuttan DP, Tadepalli A, Cholan PK, Subramanian S, Vinayagavel M. Prevalence of dental anxiety among patients attending a dental educational institution in Chennai, India--a questionnaire based study. Oral Health Dent Manag 2013;12(4):289-94.
  3. Appukuttan D, Subramanian S, Tadepalli A, Damodaran LK. Dental anxiety among adults: an epidemiological study in South India. N Am J Med Sci 2015;7(1):13-8. doi: 10.4103/1947-2714.150082. [Crossref]
  4. Tellez M, Kinner DG, Heimberg RG, Lim S, Ismail AI. Prevalence and correlates of dental anxiety in patients seeking dental care. Community Dent Oral Epidemiol 2015;43(2):135-42. doi: 10.1111/cdoe.12132. [Crossref]
  5. Seligman LD, Hovey JD, Chacon K, Ollendick TH. Dental anxiety: An understudied problem in youth. Clin Psychol Rev 2017;55:25-40. doi: 10.1016/j.cpr.2017.04.004. [Crossref]
  6. Carlsson V, Hakeberg M, Wide Boman U. Associations between dental anxiety, sense of coherence, oral health-related quality of life and health behavior--a national Swedish cross-sectional survey. BMC Oral Health 2015;15:100. doi: 10.1186/s12903-015-0088-5. [Crossref]
  7. Gaffar BO, Alagl AS, Al-Ansari AA. The prevalence, causes, and relativity of dental anxiety in adult patients to irregular dental visits. Saudi Med J 2014;35(6):598-603.
  8. Armfield JM. What goes around comes around: revisiting the hypothesized vicious cycle of dental fear and avoidance. Community Dent Oral Epidemiol 2013;41(3):279-87. doi: 10.1111/cdoe.12005. [Crossref]
  9. Armfield JM, Ketting M. Predictors of dental avoidance among Australian adults with different levels of dental anxiety. Health Psychol 2015;34(9):929-40. doi: 10.1037/hea0000186. [Crossref]
  10. Almoznino G, Zini A, Sharav Y, Shahar A, Zlutzky H, Haviv Y, et al. Sleep quality in patients with dental anxiety. J Psychiatr Res 2015;61:214-22. doi: 10.1016/j.jpsychires.2014.11.015. [Crossref]
  11. Goettems ML, Schuch HS, Demarco FF, Ardenghi TM, Torriani DD. Impact of dental anxiety and fear on dental care use in Brazilian women. J Public Health Dent 2014;74(4):310-6. doi: 10.1111/jphd.12060. [Crossref]
  12. Vermaire JH, van Houtem CM, Ross JN, Schuller AA. The burden of disease of dental anxiety: generic and disease-specific quality of life in patients with and without extreme levels of dental anxiety. Eur J Oral Sci 2016;124(5):454-8. doi: 10.1111/eos.12290. [Crossref]
  13. Beaton L, Freeman R, Humphris G. Why are people afraid of the dentist? Observations and explanations. Med Princ Pract 2014;23(4):295-301. doi: 10.1159/000357223. [Crossref]
  14. Corah NL. Development of a dental anxiety scale. J Dent Res 1969;48(4):596. doi: 10.1177/00220345690480041801. [Crossref]
  15. Humphris GM, Morrison T, Lindsay SJ. The Modified Dental Anxiety Scale: validation and United Kingdom norms. Community Dent Health 1995;12(3):143-50.
  16. Spielberger CD. Manual for the state-trait anxiety inventory (Self-evaluation questionnaire). Palo Alto, CA: Consulting Psychologists Press; 1970.
  17. Geer JH. The development of a scale to measure fear. Behav Res Ther 1965;3(1):45-53. doi: 10.1016/0005-7967(65)90040-9. [Crossref]
  18. Kvale G, Berg E, Nilsen CM, Raadal M, Nielsen GH, Johnsen TB, et al. Validation of the Dental Fear Scale and the Dental Belief Survey in a Norwegian sample. Community Dent Oral Epidemiol 1997;25(2):160-4.
  19. Sadana G, Grover R, Mehra M, Gupta S, Kaur J, Sadana S. A novel Chotta Bheem-Chutki scale for dental anxiety determination in children. J Int Soc Prev Community Dent 2016;6(3):200-5. doi: 10.4103/2231-0762.183108. [Crossref]
  20. Kleinknecht RA, Thorndike RM, McGlynn FD, Harkavy J. Factor analysis of the dental fear survey with cross-validation. J Am Dent Assoc 1984;108(1):59-61.
  21. Armfield JM. How do we measure dental fear and what are we measuring anyway? Oral Health Prev Dent 2010;8(2):107-15.
  22. Bonafe FS, Campos JA. Validation and Invariance of the Dental Anxiety Scale in a Brazilian sample. Braz Oral Res 2016;30(1):e138. doi: 10.1590/1807-3107BOR-2016.vol30.0138. [Crossref]
  23. Yuan S, Freeman R, Lahti S, Lloyd-Williams F, Humphris G. Some psychometric properties of the Chinese version of the Modified Dental Anxiety Scale with cross validation. Health Qual Life Outcomes 2008;6:22. doi: 10.1186/1477-7525-6-22. [Crossref]
  24. Campos JA, Presoto CD, Martins CS, Domingos PA, Maroco J. Dental Anxiety: Prevalence and Evaluation of Psychometric Properties of a Scale. Psychology, Community & Health 2013;2(1):19-27. doi: 10.5964/pch.v2i1.18. [Crossref]
  25. Facco E, Zanette G, Manani G. Italian version of Corah’s Dental Anxiety Scale: normative data in patients undergoing oral surgery and relationship with the ASA physical status classification. Anesth Prog 2008;55(4):109-15. doi: 10.2344/0003-3006-55.4.109. [Crossref]
  26. Beaton DE, Bombardier C, Guillemin F, Ferraz MB. Guidelines for the process of cross-cultural adaptation of self-report measures. Spine (Phila Pa 1976) 2000;25(24):3186-91.
  27. Luyk NH, Beck FM, Weaver JM. A visual analogue scale in the assessment of dental anxiety. Anesth Prog 1988;35(3):121-3.
  28. Appukuttan D, Vinayagavel M, Tadepalli A. Utility and validity of a single-item visual analog scale for measuring dental anxiety in clinical practice. J Oral Sci 2014;56(2):151-6.
  29. Facco E, Zanette G, Favero L, Bacci C, Sivolella S, Cavallin F, et al. Toward the validation of visual analogue scale for anxiety. Anesth Prog 2011;58(1):8-13. doi: 10.2344/0003-3006-58.1.8. [Crossref]
  30. Maroco J. [Analysis of structural equations]. Lisbon: Report Number; 2010.
  31. Giri J, Pokharel PR, Gyawali R, Bhattarai B. Translation and Validation of Modified Dental Anxiety Scale: The Nepali Version. Int Sch Res Notices 2017;2017:5495643. doi: 10.1155/2017/5495643. [Crossref]
  32. Acharya S. Factors affecting dental anxiety and beliefs in an Indian population. J Oral Rehabil 2008;35(4):259-67. doi: 10.1111/j.1365-2842.2007.01777.x. [Crossref]
  33. Appukuttan D, Datchnamurthy M, Deborah SP, Hirudayaraj GJ, Tadepalli A, Victor DJ. Reliability and validity of the Tamil version of Modified Dental Anxiety Scale. J Oral Sci 2012;54(4):313-20.
  34. Marya CM, Grover S, Jnaneshwar A, Pruthi N. Dental anxiety among patients visiting a dental institute in Faridabad, India. West Indian Med J 2012;61(2):187-90.
  35. Kirova DG, Atanasov DT, Lalabonova CK, Janevska S. Dental anxiety in adults in Bulgaria. Folia Med (Plovdiv) 2010;52(2):49-56.
  36. Humphris GM, Dyer TA, Robinson PG. The modified dental anxiety scale: UK general public population norms in 2008 with further psychometrics and effects of age. BMC Oral Health 2009;9:20. doi: 10.1186/1472-6831-9-20. [Crossref]
  37. Tunc EP, Firat D, Onur OD, Sar V. Reliability and validity of the Modified Dental Anxiety Scale (MDAS) in a Turkish population. Community Dent Oral Epidemiol 2005;33(5):357-62. doi: 10.1111/j.1600-0528.2005.00229.x. [Crossref]
  38. Saatchi M, Abtahi M, Mohammadi G, Mirdamadi M, Binandeh ES. The prevalence of dental anxiety and fear in patients referred to Isfahan Dental School, Iran. Dent Res J (Isfahan) 2015;12(3):248-53.
  39. Malvania EA, Ajithkrishnan CG. Prevalence and socio-demographic correlates of dental anxiety among a group of adult patients attending a dental institution in Vadodara city, Gujarat, India. Indian J Dent Res 2011;22(1):179-80. doi: 10.4103/0970-9290.79989. [Crossref]
  40. Pekkan G, Kilicoglu A, Hatipoglu H. Relationship between dental anxiety, general anxiety level and depression in patients attending a university hospital dental clinic in Turkey. Community Dent Health 2011;28(2):149-53.
  41. Halonen H, Salo T, Hakko H, Rasanen P. The association between dental anxiety, general clinical anxiety and depression among Finnish university students. Oral Health Dent Manag 2014;13(2):320-5.
  42. Talo Yildirim T, Dundar S, Bozoglan A, Karaman T, Dildes N, Acun Kaya F, et al. Is there a relation between dental anxiety, fear and general psychological status? PeerJ 2017;5:e2978. doi: 10.7717/peerj.2978. [Crossref]