PREDICTION OF CARIES RISK
ARTICLE ABSTRACT The study sample consisted of 100 children with visual impairment aged 6–14 years. 6-n-propylthiouracil (PROP) sensitivity test was carried out. The Caries experience was recorded, estimation of Streptococcus mutans done and their taste likes and dislikes assessed through a food preference questionnaire. The Caries experience and S. mutans levels were highest in the non-tasters, comparatively low in medium tasters and the least in the supertasters. Dietary preferences indicated tasters were sweet dislikers and non-tasters, sweet likers. PROP test can be a useful tool in determining genetic taste sensitivity levels amongst the visually impaired children and thus used as a screening tool in those children who are at a high risk of developing dental caries.
KEY WORDS: 6-n-propylthiouracil, labeled magnitude scale, dental caries, S. mutans
PROP test: prediction of caries risk by genetic taste perception among the visually impaired children Vabitha Shetty, MDS;1* Pooja B.L.;2 Amitha M. Hegde, BSc, BDS, MDS3 1Professor; 2Postgraduate
student; 3Sr Professor and Head of the Department, Department of Pedodontics and Preventive Children Dentistry, A.B. Shetty Memorial Institute of Dental Sciences, Mangalore, Karnataka, India. *Corresponding author e-mail: [email protected] Spec Care Dentist 34(1): 34-40, 2014
Int r od uct ion
Oral health is considered to be a mirror image of general health. Oral health is a vital component of overall health and is all the more important for children with special health needs.1 Special and medically compromised children present a unique population that challenges the dentist’s skills and knowledge.2 Challenges to the oral health are more complex for visually impaired children, who are often unable to adequately apply the techniques necessary to control plaque and are at greater risk for developing dental diseases.3 Literature review reveals high incidence of dental caries and periodontal diseases in physically handicapped children including the children who are visually impaired and they present a unique problem in dental management of this population because the chronicity of oral disease complicate the primary physical or mental disability.4 The development of dental caries is dependent upon critical interrelationship between susceptible host/tooth surface, specific oral bacteria and dietary carbohydrates. Several studies have indicated that children with high sugar intake have higher caries rate and this is positively related to sweet score and total sugar exposure.5 Inherited behavior and taste thresholds may play an important role in the frequency of carbohydrate intake. Genetic sensitivity to taste may be associ-
34 S p e c C a r e D e n t i s t 3 4 ( 1 ) 2 0 1 4
scd_307.indd 34
ated with the preference for rejection of some foods by children.6-8 The ability to taste bitter thiourea compound such as 6-n-propylthiouracil (PROP) is inherited. PROP tasters are more sensitive to many oral sensations, including bitter and sweet tastes and the sensation of fats. PROP status influences food selection and dietary habits in children.9,10 PROP in clinical practice is a medication used in the treatment of Grave’s disease (Hyperthyroidism).11 Being extremely bitter, PROP can be tasted at a very low concentration and this bitter property of PROP has proved to be a useful tool in determining the genetic sensitivity levels to bitter and sweet taste.12 PROP has already proven to be a useful tool to identify children at greater risk for dental caries by identifying the genetic sensitivity levels of the children.13,14 This study investigated the ability of the PROP test to facilitate the identification of children with visual impairment who are at an enhanced risk for developing dental caries thus enabling us to
©2012 Special Care Dentistry Association and Wiley Periodicals, Inc. doi: 10.1111/j.1754-4505.2012.00307.x
05/12/13 11:59 AM
PREDICTION OF CARIES RISK
initiate aggressive preventive oral health care programs for them.
M ater ials and me tho ds Source of data A total number of 100 children with total visual impairment between the age groups of 6–14 years belonging to both the sexes formed the study group. They were selected from two schools and centers for the visually impaired, namely, Government Blind School, Kasargod, Kerala and Karnataka Welfare Association for the Blind, Bangalore. Informed consent was taken from all parents/caretakers and ethical clearance obtained from the concerned institution. Ours is a self-funded research study.
Exclusion criteria 1 Subjects who are un-cooperative. 2 Subjects with underlying systemic disease. 3 Subjects under any medication and antibiotics three months before the study.
M ethodology Preparation of the PROP strips Pure samples of PROP was obtained from Macleod’s pharmaceuticals, Mumbai and sterile PROP strips containing 6-n-propyltthiouracil were prepared at N.G.S.M Institute of Pharmaceutical Sciences, Mangalore.15 Whatman filter paper was cut into 2 × 2 cm size and sterilized in an autoclave at 121°C for 15 minutes. The sterilized strips were weighed and stored in the desicator until they were used for further preparation. 6-n-propylthiouracil (10 mg/ml) was dissolved in 5 ml of alcohol in a beaker. Ten previously cut and sterilized Whatman filter paper strips were soaked in the above solution for one hour for the complete absorption of the drug. The strips were removed and allowed to dry at room temperature. Approximately 1.6 mg of drug was impregnated on each strip.15
Shetty et al.
scd_307.indd 35
PROP sensitivity test PROP sensitivity test was carried out by placing the filter paper containing approximately 1.6 mg of 6-n-propylthiouracil on the dorsal surface of the anterior two-third region of the tongue for 30 seconds. Based on their ability to rate the intensity of bitter taste on a modified labeled magnitude scale (LMS).16 these children were subdivided into two groups as PROP tasters and PROP non-tasters. The tasters were further classified as super tasters and medium tasters.16 In our study the examiner had to verbally explain in the local language regarding the details of LMS to the children and also about the strongest imaginable bitter taste perception with suitable dietary examples.
Recording of caries experience The visually impaired children were examined at their respective schools/ centers, seated on an ordinary chair, under good illumination using a sterile mouth mirror and CPI probe while taking protective cross infection control measures. The Caries experience was recorded using DMFT/dft indices. A total DMFT/dft score of more than five was considered to have increased caries activity.17
Estimation of streptococcus mutans levels Streptococcus mutans colony count was done using unstimulated salivary samples using the mutans-sanguis selective medium agar plates.18,19
Evaluation of dietary preferences A food preference questionnaire was prepared (questionnaire enclosed as Annexure 2) and given to the parents/ caretakers/teachers of the children to establish their sweet, sour and strong taste preferences.20 We considered a child frequently preferring two or more of the foods designated under the sweet category as a sweet liker, while a child frequently preferring two or more of the foods designated under bitter/spicy/ pungent food was considered a disliker.
Table 1. Distribution of genetic taste sensitivity based on PROP status. Prop status
Percentage
Super tasters
27%
Medium tasters
65%
Non tasters
8%
Total
100%
St a t is t ica l a na ly si s
All collected data were collected on forms and subjected to Statistical analysis using the Kruskal Wallis Test (H) and Chi-Square Test (X2). The measures of central tendency(mean)and standard deviation were calculated for variables. We assessed the association between PROP status to caries experience by Kruskal Wallis test (H = 18.40 for DMFT and H = 43.68 for dft, p < .001)and PROP status to S. mutans counts(X2 = 49.88) and dietary preferences(X2 = 22.677) by chi-square test(p < .001). A statistical package SPSS ver.17.0 was used to do the analysis. p < .05 was considered as significant.
R es ul t s
Table 1 shows that of the total population, 92% were tasters (Super tasters-27%, Medium tasters-65%) and only 8% were non-tasters. Tasters accounted for more than three fourth of all the children included in the study. When the differences in the mean values of the DMFT/dft scores were compared among the various taster groups shown in Table 2, we observed that in the Permanent dentition, super tasters and medium tasters had a mean DMFT value of 0.259 and 1.349, respectively, whereas the non-tasters had a value of 2.625, which was statistically very highly significant (p < .001) In the mixed dentition, the mean dft values were 0 and 0.184 for super tasters and medium tasters, respectively, whereas for non-tasters, a much higher value of 5.125 was observed, which was statistically very highly significant (p < .001).
S p e c C a r e D e n t i s t 3 4 ( 1 ) 2 0 1 4 35
05/12/13 11:59 AM
PREDICTION OF CARIES RISK
Table 2. Comparison of caries experience among the tasters and non-tasters. PROP TEST DMFT
dft
N
Mean
Std. Deviation
Super tasters
27
0.2593
0.44658
Medium tasters
65
1.3486
1.30734
Non tasters
8
2.6250
4.17261
Super tasters
27
0.0
0.0
Medium tasters
65
0.1846
0.84580
Non tasters
8
5.1250
4.08613
H
P
18.40
ARTICLE ABSTRACT The study sample consisted of 100 children with visual impairment aged 6–14 years. 6-n-propylthiouracil (PROP) sensitivity test was carried out. The Caries experience was recorded, estimation of Streptococcus mutans done and their taste likes and dislikes assessed through a food preference questionnaire. The Caries experience and S. mutans levels were highest in the non-tasters, comparatively low in medium tasters and the least in the supertasters. Dietary preferences indicated tasters were sweet dislikers and non-tasters, sweet likers. PROP test can be a useful tool in determining genetic taste sensitivity levels amongst the visually impaired children and thus used as a screening tool in those children who are at a high risk of developing dental caries.
KEY WORDS: 6-n-propylthiouracil, labeled magnitude scale, dental caries, S. mutans
PROP test: prediction of caries risk by genetic taste perception among the visually impaired children Vabitha Shetty, MDS;1* Pooja B.L.;2 Amitha M. Hegde, BSc, BDS, MDS3 1Professor; 2Postgraduate
student; 3Sr Professor and Head of the Department, Department of Pedodontics and Preventive Children Dentistry, A.B. Shetty Memorial Institute of Dental Sciences, Mangalore, Karnataka, India. *Corresponding author e-mail: [email protected] Spec Care Dentist 34(1): 34-40, 2014
Int r od uct ion
Oral health is considered to be a mirror image of general health. Oral health is a vital component of overall health and is all the more important for children with special health needs.1 Special and medically compromised children present a unique population that challenges the dentist’s skills and knowledge.2 Challenges to the oral health are more complex for visually impaired children, who are often unable to adequately apply the techniques necessary to control plaque and are at greater risk for developing dental diseases.3 Literature review reveals high incidence of dental caries and periodontal diseases in physically handicapped children including the children who are visually impaired and they present a unique problem in dental management of this population because the chronicity of oral disease complicate the primary physical or mental disability.4 The development of dental caries is dependent upon critical interrelationship between susceptible host/tooth surface, specific oral bacteria and dietary carbohydrates. Several studies have indicated that children with high sugar intake have higher caries rate and this is positively related to sweet score and total sugar exposure.5 Inherited behavior and taste thresholds may play an important role in the frequency of carbohydrate intake. Genetic sensitivity to taste may be associ-
34 S p e c C a r e D e n t i s t 3 4 ( 1 ) 2 0 1 4
scd_307.indd 34
ated with the preference for rejection of some foods by children.6-8 The ability to taste bitter thiourea compound such as 6-n-propylthiouracil (PROP) is inherited. PROP tasters are more sensitive to many oral sensations, including bitter and sweet tastes and the sensation of fats. PROP status influences food selection and dietary habits in children.9,10 PROP in clinical practice is a medication used in the treatment of Grave’s disease (Hyperthyroidism).11 Being extremely bitter, PROP can be tasted at a very low concentration and this bitter property of PROP has proved to be a useful tool in determining the genetic sensitivity levels to bitter and sweet taste.12 PROP has already proven to be a useful tool to identify children at greater risk for dental caries by identifying the genetic sensitivity levels of the children.13,14 This study investigated the ability of the PROP test to facilitate the identification of children with visual impairment who are at an enhanced risk for developing dental caries thus enabling us to
©2012 Special Care Dentistry Association and Wiley Periodicals, Inc. doi: 10.1111/j.1754-4505.2012.00307.x
05/12/13 11:59 AM
PREDICTION OF CARIES RISK
initiate aggressive preventive oral health care programs for them.
M ater ials and me tho ds Source of data A total number of 100 children with total visual impairment between the age groups of 6–14 years belonging to both the sexes formed the study group. They were selected from two schools and centers for the visually impaired, namely, Government Blind School, Kasargod, Kerala and Karnataka Welfare Association for the Blind, Bangalore. Informed consent was taken from all parents/caretakers and ethical clearance obtained from the concerned institution. Ours is a self-funded research study.
Exclusion criteria 1 Subjects who are un-cooperative. 2 Subjects with underlying systemic disease. 3 Subjects under any medication and antibiotics three months before the study.
M ethodology Preparation of the PROP strips Pure samples of PROP was obtained from Macleod’s pharmaceuticals, Mumbai and sterile PROP strips containing 6-n-propyltthiouracil were prepared at N.G.S.M Institute of Pharmaceutical Sciences, Mangalore.15 Whatman filter paper was cut into 2 × 2 cm size and sterilized in an autoclave at 121°C for 15 minutes. The sterilized strips were weighed and stored in the desicator until they were used for further preparation. 6-n-propylthiouracil (10 mg/ml) was dissolved in 5 ml of alcohol in a beaker. Ten previously cut and sterilized Whatman filter paper strips were soaked in the above solution for one hour for the complete absorption of the drug. The strips were removed and allowed to dry at room temperature. Approximately 1.6 mg of drug was impregnated on each strip.15
Shetty et al.
scd_307.indd 35
PROP sensitivity test PROP sensitivity test was carried out by placing the filter paper containing approximately 1.6 mg of 6-n-propylthiouracil on the dorsal surface of the anterior two-third region of the tongue for 30 seconds. Based on their ability to rate the intensity of bitter taste on a modified labeled magnitude scale (LMS).16 these children were subdivided into two groups as PROP tasters and PROP non-tasters. The tasters were further classified as super tasters and medium tasters.16 In our study the examiner had to verbally explain in the local language regarding the details of LMS to the children and also about the strongest imaginable bitter taste perception with suitable dietary examples.
Recording of caries experience The visually impaired children were examined at their respective schools/ centers, seated on an ordinary chair, under good illumination using a sterile mouth mirror and CPI probe while taking protective cross infection control measures. The Caries experience was recorded using DMFT/dft indices. A total DMFT/dft score of more than five was considered to have increased caries activity.17
Estimation of streptococcus mutans levels Streptococcus mutans colony count was done using unstimulated salivary samples using the mutans-sanguis selective medium agar plates.18,19
Evaluation of dietary preferences A food preference questionnaire was prepared (questionnaire enclosed as Annexure 2) and given to the parents/ caretakers/teachers of the children to establish their sweet, sour and strong taste preferences.20 We considered a child frequently preferring two or more of the foods designated under the sweet category as a sweet liker, while a child frequently preferring two or more of the foods designated under bitter/spicy/ pungent food was considered a disliker.
Table 1. Distribution of genetic taste sensitivity based on PROP status. Prop status
Percentage
Super tasters
27%
Medium tasters
65%
Non tasters
8%
Total
100%
St a t is t ica l a na ly si s
All collected data were collected on forms and subjected to Statistical analysis using the Kruskal Wallis Test (H) and Chi-Square Test (X2). The measures of central tendency(mean)and standard deviation were calculated for variables. We assessed the association between PROP status to caries experience by Kruskal Wallis test (H = 18.40 for DMFT and H = 43.68 for dft, p < .001)and PROP status to S. mutans counts(X2 = 49.88) and dietary preferences(X2 = 22.677) by chi-square test(p < .001). A statistical package SPSS ver.17.0 was used to do the analysis. p < .05 was considered as significant.
R es ul t s
Table 1 shows that of the total population, 92% were tasters (Super tasters-27%, Medium tasters-65%) and only 8% were non-tasters. Tasters accounted for more than three fourth of all the children included in the study. When the differences in the mean values of the DMFT/dft scores were compared among the various taster groups shown in Table 2, we observed that in the Permanent dentition, super tasters and medium tasters had a mean DMFT value of 0.259 and 1.349, respectively, whereas the non-tasters had a value of 2.625, which was statistically very highly significant (p < .001) In the mixed dentition, the mean dft values were 0 and 0.184 for super tasters and medium tasters, respectively, whereas for non-tasters, a much higher value of 5.125 was observed, which was statistically very highly significant (p < .001).
S p e c C a r e D e n t i s t 3 4 ( 1 ) 2 0 1 4 35
05/12/13 11:59 AM
PREDICTION OF CARIES RISK
Table 2. Comparison of caries experience among the tasters and non-tasters. PROP TEST DMFT
dft
N
Mean
Std. Deviation
Super tasters
27
0.2593
0.44658
Medium tasters
65
1.3486
1.30734
Non tasters
8
2.6250
4.17261
Super tasters
27
0.0
0.0
Medium tasters
65
0.1846
0.84580
Non tasters
8
5.1250
4.08613
H
P
18.40
