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Year : 2016  |  Volume : 6  |  Issue : 6  |  Page : 523-528
Caries risk in children of Udaipur City, India using genetic taste sensitivity to 6-n-propylthiouracil

1 Department of Pediatric and Preventive Dentistry, Mithila Minority Dental College and Hospital, Darbhanga, Bihar, India
2 Department of Pediatric and Preventive Dentistry, Darshan Dental College and Hospital, Udaipur, Rajasthan, India
3 Department of Pediatric and Preventive Dentistry, Goenka Research Institute of Dental Science, Gandhinagar, Gujarat, India
4 Department of Pediatric and Preventive Dentistry, Ahmedabad Dental College, Ahmedabad, Gujarat, India
5 Ex-Private Practitioner, Ahmedabad, Gujarat, India

Date of Submission08-Apr-2016
Date of Acceptance03-Oct-2016
Date of Web Publication12-Dec-2016

Correspondence Address:
Payel Karmakar
Department of Pediatric and Preventive Dentistry, Mithila Minority Dental College and Hospital, Laheria Sarai, Bihar
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2231-0762.195508

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Aims and Objectives: Dental caries still remains the single most common disease of childhood. The present study was conducted to test the hypothesis that a higher prevalence of dental caries would be observed among nontaster children compared to medium tasters or supertasters of 6n propylthiouracil impregnated filter papers. Materials and Methods: The present study was conducted on a random sample of 600 school children aged 6–12 years in Udaipur city. 6-n-propylthiouracil strips were prepared. The food preference questionnaire was filled by the participants, and their decayed missing filled status as well as taste sensitivity to the propylthiouracil impregnated filter papers were noted. The data obtained was then used for statistical analysis using chi square, analysis of variance, and Students t-tests with the consult of a statistician using the Statistical Package for the Social Sciences version 17 software. Results: Nontasters had a greater caries experience than the supertasters and medium tasters. Females were found to be more tasters than nontasters. It was also found that nontasters belonged to caries active group more than the tasters. Conclusion: The caries status was higher among the nontaster children with more sweet preference than in taster children and they belonged more to the caries active group.

Keywords: Caries, caries active, caries free, propylthiouracil, taste

How to cite this article:
Karmakar P, Arora R, Patel C, Sarvaiya B, Singh A, Patel M. Caries risk in children of Udaipur City, India using genetic taste sensitivity to 6-n-propylthiouracil. J Int Soc Prevent Communit Dent 2016;6:523-8

How to cite this URL:
Karmakar P, Arora R, Patel C, Sarvaiya B, Singh A, Patel M. Caries risk in children of Udaipur City, India using genetic taste sensitivity to 6-n-propylthiouracil. J Int Soc Prevent Communit Dent [serial online] 2016 [cited 2022 Jul 1];6:523-8. Available from: https://www.jispcd.org/text.asp?2016/6/6/523/195508

   Introduction Top

Vargas [1] in 1998 suggested ethnicity and socio-economic status as having roles in caries prevalence where as Ernest Newbrun in 1967 described sucrose as the “arch-criminal of dental caries.” Data of sugar consumption per capita with caries prevalence have clearly associated high caries prevalence with high sugar consumption.[2] The physiological mechanisms that affect a child's craving for sweets have not been well documented among the recent studies.[3]

6-n-propylthiouracil (PROP) and phenythiocarbamide (PTC) are members of a class of compounds known as “thioureas.” These compounds carry the chemical group N-C5S. This compound gives thioureas their characteristic bitter taste. PROP are of significant interest to taste researchers. They act not only as tools for understanding the genetic transmittance of taste but for gaining knowledge into the seemingly endless variations in taste preferences and food habits. Taste sensitivity to PTC and PROP can be determined by the use of threshold methods. The threshold is defined as the lowest concentration of a test solution that can be distinguished from plain water. Tasters have very low thresholds for PROP (i.e., they can taste even at very low concentrations), whereas nontasters have higher thresholds.[4]

The present study was conducted to test the hypothesis that a higher prevalence of dental caries would be observed among nontaster children compared to children who are medium tasters or supertasters among school going children.

   Materials and Methods Top

Source of data

The present study was conducted among a random sample of 600 boys and girls aged 6–12 years. In this study, a wide age range of 6-12 years was selected. This is a dynamic phase of growth and represents mixed dentition period in children. A similar age group was also selected by Verma et al.,[5] Sharma and Hegde,[6] and Rupesh and Nayak [7] Boys and girls were both considered to take into account the gender differences and differences in the growth milestones, body structure, and hormonal effects. Labelled magnitude scale (LMS) was used for the study. LMS [8] provided not only an absolute lower bound at which there is no sensation but also an absolute upper bound labeled “strongly imaginable of any kind.” Both Bartoshuket al.[9] and Green et al.[8] believed that preparing the scale in this manner puts different people's responses on the same metric scale creating a “universal ruler.”

A two-stage random sampling method was followed. The school served as the primary sampling unit and individual child as the unit of enquiry. Children were selected proportionate to the number of children in each school. The children were selected by systematic random sampling.

Study areas

Information regarding the number of primary and upper primary schools in the Udaipur district was procured from the office of the District Education Officer, Udaipur district.

Study schedule

A detailed monthly schedule was prepared well in advance by informing and obtaining consent from the authorities of respective institutes.

Ethical clearance

This proposed study was reviewed by the institutional ethical committee of Darshan Dental College and Hospital, Udaipur city, Rajasthan and clearance was obtained.

Exclusion criteria

  • Children with any systemic disease.
  • Children with unstable mental condition.
  • Children whose parents did not give consent or failed to bring the consent form on the date of examination.
  • Children under any regular medication.
  • Children with exaggerated gag reflex.

Preparation of 6-n-propylthiouracil strips

The pure sample of PROP was obtained from the Macleod's pharmaceuticals, Mumbai. PROP strips were made in the Sukhariya University in The Department of Pharmacology, Udaipur. Whattman filter paper was procured and cut into 2 × 2 cm sizes and were sterilized in an autoclave at 121°C for 15 min. The sterilized strips were weighed and stored in desiccators and the preweight of the papers was noted.

First, in a beaker, PROP (10 mg/ml) was dissolved in 5 ml of ethyl alcohol. Ten previously cut and sterilized Whattman filter paper strips were weighed and then kept in the PROP solution for 1 h for complete absorption of the drug. The strips were removed and were then air dried at room temperature. The weight of the strips after drying was recorded. The preweight and postweight difference was noted down. It was found that in each strip of filter paper approximately 1.6 mg of drug was impregnated.

PROP sensitivity test

PROP sensitivity test was carried out by placing the PROP impregnated filter paper strips on the dorsal surface of the anterior two-third region of the subject tongue for 30 s.

The participating children were divided into two groups as PROP tasters and PROP nontasters. This was done by their ability to rate the intensity of bitter taste of the PROP impregnated filter paper strips on the LMS.[8]

PROP taster status

The children were subdivided as follows:

  • Supertasters are individuals who have low taste threshold to bitter and sweet substances. This set of population perceives the taste as strongest imaginable and very strong.
  • Medium tasters are those who have the ability to perceive bitter and sweet substances in moderation.
  • Nontasters are the individuals who have high taste threshold to the bitter and sweet substances. They perceive the taste as weak and barely detectable.

Clinical assessment and data collection

Clinical examinations were performed by a single examiner (postgraduate student) in well-lighted classrooms. The examination was carried out with the help of a mouth mirror and an explorer. The students present on that particular day were selected for the examination.

Evaluation of dietary preferences

Food preference questionnaires were distributed among the students. The older children filled the questionnaire by themselves whereas the parents of younger children were asked to fill the questionnaire.

Recording of caries status


A tooth was diagnosed as caries when there was catch with No. 23 explorer accompanied by any of the following signs

  • If there is softness at the base area of the lesion.
  • If there is any opacity adjacent to the region signifying demineralization.
  • If there is any soft enamel adjoining to the region. The enamel can be scraped away by an explorer thus indicating its softness.

When in doubt, caries was not recorded as present. Missing teeth included only those teeth that were missing due to caries and those teeth that were indicated for extraction. Teeth that have been extracted for orthodontic reasons, unerupted teeth, or congenitally missing were not included. Teeth were recorded as filled if only they had permanent restorations. Indices were calculated for whole set of dentition, 32 for permanent dentition, and 20 for primary teeth. Thus, the highest DMFT and dmft scores possible were 32 and 20. respectively.

The data obtained was subjected statistical analysis. The analysis was done by using chi square test, analysis of variance test, and Students t-test using the SPSS Statistics for Windows, Version 17.0. Chicago: SPSS Inc.

   Results Top

Two-third of the total population were tasters (supertasters as well as medium tasters), and the remaining one-third were nontasters [Graph 1]. Females belonged more to the taster group, with P value less than 0.001 [Table 1]. The total decayed, missing and filled (dmft) value of the taster group was much lower than nontaster children (P < 0.001) [Table 2]. There was no statistically significant difference in the dmft/DMFT scores among both the sexes [Table 3]. The distribution of caries free and caries active children among the taster and nontaster children revealed that, in the taster group, only 2.32% were caries active. Caries active children belonged more to the nontaster group than the taster group [Graph 2].

Table 1: Gender distribution among the various groups of tasters

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Table 2: Comparison of mean and standard deviation of dmft among tasters and nontasters

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Table 3: Comparison of mean and standard deviation of dmft/DMFT with gender

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   Discussion Top

A total of 65.7% children were found to be tasters and 34.3% were found to be nontasters in the present study. This is in accordance with the study reported by Lin [9] The results in the present study indicated that, in general, the overall caries status (mean DMFT/dmft) was significantly much higher for non taster children. Lin [9] Verma et al.,[5] Sharma et al.,[6] and Rupesh and Nayak [7] also reported similar results. This could be due to the overall increase in the consumption of sugar rich food by nontaster children than the taster group and their preference of sweet and cariogenic food items. Verma et al.[10] also found similar results [Table 4].
Table 4: Comparison of food preference with taster status

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Among females, tasters accounted for more than one-third of the group. The findings were in accordance to

the studies by Duffy et al.,[11] Drewnowski et al.,[12] and Hussain et al.[13] This may be due to the presence of more fungiform papillae among females. Though Feeney and Hayes [14] found a contradictory result.

Dietary preferences showed that among nontasters only 29.4% disliked sweets. Fischer [15] in 1967 found that PTC tasters showed more dislike toward food items. Looy and Weingarten [16] reported that participants who did not like sucrose were nearly all PROP tasters. Loper et al.[17] found that PROP nontasters tend to have a higher calorie intake. Monneuse et al.[18] reported that both sex and age determined the preference for sweet taste. Females among all age groups preferred low sugar concentrations than males.

The present study included 234 children who were caries free and 58 children who were caries active. Most of the caries active children belonged to the nontaster group, and the result was statistically highly significant. A reverse result was observed for caries free children. Thus, the taste preference can be considered to be one of the factor for such distribution of caries free and caries active children. Shetty et al.[19] also found a similar result.

The limitations of the study were:

  • The children falling into a medium category were difficult to categorize, leading to comparable results with the other two groups occasionally.
  • Children less than 6 years of age were not selected for the present study due to their inability to comprehend the LMS scale.[5] However, Hu et al.[20] and Sachdeva et al.[21] stated the importance of early identification and introduction of preventive measures.
  • The salivary factors in the development of dental caries were not included in this study whereas various studies by different authors such as Bhayat et al.[22] and Singh et al.[23] have found increase in salivary Streptococcus mutans, decrease in salivary flow rate, and increase in the severity of dental caries.
  • In China, Yang et al.[24] found a correlation between caries status and severity with growth and development retardation in children. The present study did not take these factors into consideration.
  • Ingle et al.[25] found caries incidence to be higher among government school children than private school children. In the present study, caries difference were not compared among schools.

Scope of the study:

  • There is a rising trend in the dental caries incidences and decrease in the total tooth loss, as seen from a study conducted between 1990 and 2010 by Kassebaum et al.[26] PROP test, thus, can be carried out in the mixed dentition period and preventive measures can be undertaken accordingly.
  • Scope of the study also includes consideration of hormonal factors. Bennadi et al.[27]
  • Socioeconomic factors and basal metabolic rate (BMR) can also considered in further studies.

   Conclusion Top

The caries status was higher among the nontaster children with more sweet preference than in the taster children. Females belonged to the taster groups with a lower caries experience. Caries active individuals were more in the nontaster group whereas the caries free individuals more in the taster group.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Vargas CM, Crall JJ, Schneider DA. Socio-demographic distribution of pediatric dental caries: NHANES III, 1988-1994. J Am Dent Assoc 1998;129:1229-38.  Back to cited text no. 1
Lehl G, Bansal K, Sekhon R. Relationship between cariogenic diet and dental caries as evaluated from a 5-day diet diary in 4-12 yr old children. J Indian Soc Pedod Prev Dent 1999;17:119-21.  Back to cited text no. 2
Downer MC. Caries experience and sucrose availability: An analysis of the relationship in the United Kingdom over 50 years. Community Dent Health 1999;16:18-21.  Back to cited text no. 3
Tepper BJ. Genetics of Perception 6-n-Propylthiouracil: A Genetic Marker for Taste, with Implications for Food Preference and Dietary Habits. Am J Hum Genet 1998;63:1271-6.  Back to cited text no. 4
Verma P, Shetty V, Hegde A. Propylthiouracil(Prop) A Tool to Determine Taster Status in Relation to Caries Experience, Streptococcus Mutans Levels And Dietary Preferences In Children. J Clin Pediatr Dent 2006;31:113-7.  Back to cited text no. 5
Sharma A, Hegde A. Genetic Sensitivity To 6n Propylthiouracil (Prop) As A Screening Tool For Obesity And Dental Caries In Children. J Clin Pediatr Dent 2008;33:107-11.  Back to cited text no. 6
Rupesh S, Nayak U. Genetic Sensitivity to the Bitter Taste of 6-N Propylthiouracil: A New Risk Determinant for Dental Caries in Children. J Indian Soc Pedod Prev Dent 2006;24:63-8.  Back to cited text no. 7
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Fischer R. Genetics and gustatory chemoreception in man and other primates. In: Kare MR, Mailer O, editors. The chemical senses and nutrition. Baltimore: John Hopkins Press; 1967. p. 621-81.  Back to cited text no. 15
Looy H, Weingarten HP. Facial expressions and genetic sensitivity to 6-n-propylthiouracil predict hedonic response to sweet. Physiol Behav 1992;52:75-82.  Back to cited text no. 16
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  [Table 1], [Table 2], [Table 3], [Table 4]

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