Year : 2010 | Volume
: 21 | Issue : 2 | Page : 266--269
Role of bitewing in enhancing the assessment of DMFS index in a group of Indian adolescents
Praveena Tantradi1, V Sreenivasan2, Harish Kadaganche3,
1 Department of Oral Medicine and Radiology, Maratha Mandal's N.G.H. Institute of Dental Sciences and Research Center, Belgaum, Karnataka, India
2 Department of Oral Medicine and Radiology, Subharati Dental College, Meerut, India
3 Department of Oral Medicine and Radiology, Vaidik Dental College, Daman, India
Department of Oral Medicine and Radiology, Maratha Mandal«SQ»s N.G.H. Institute of Dental Sciences and Research Center, Belgaum, Karnataka
Context: Caries epidemiological studies based on clinical examination alone tend to underestimate proximal caries.
Aims: This study aims to determine the additional value of radiographic examination (bitewings) compared to clinical examination in assessing posterior proximal caries. It also aims to determine the radiographic multiplication /adjusting / correction factors by which a clinical decayed surface (D-S) and decayed-missing-filled surfaces (DMFS) score could be multiplied, to obtain an actual D-S and DMFS score
Materials and Methods: Two groups of 100 subjects each, in the age range of 16-20 years, were examined clinically for caries and their DMFS index recorded. Both groups were subjected to bitewing radiographs to detect the clinically undiagnosed posterior proximal caries. The radiographic adjusting factors were determined for group A. To check its repeatability and thus its usefulness, radiographic correction factor was determined for Group B.
Statistical Analysis: The results were statistically analyzed with the use of means, standard deviations, regression equation and «DQ»Z«DQ» test. Level of significance was determined at P > 0.05.
Results: A significant number of clinically undetected proximal caries was diagnosed with the help of bitewing radiographs. The difference between the radiographic adjusting/correction factor for D-S and DMFS score for the two groups was statistically not significant (P > 0.05) thus verifying the repeatability of the radiographic correction factors.
Conclusion: The radiographic correction factors can be used to obtain a more precise estimate of true caries prevalence in a particular study population without having to subject all individuals to radiographic examination.
|How to cite this article:|
Tantradi P, Sreenivasan V, Kadaganche H. Role of bitewing in enhancing the assessment of DMFS index in a group of Indian adolescents.Indian J Dent Res 2010;21:266-269
|How to cite this URL:|
Tantradi P, Sreenivasan V, Kadaganche H. Role of bitewing in enhancing the assessment of DMFS index in a group of Indian adolescents. Indian J Dent Res [serial online] 2010 [cited 2021 May 13 ];21:266-269
Available from: https://www.ijdr.in/text.asp?2010/21/2/266/66653
The process of quantifying the disease prevalence, incidence and related factors is an important operation - one that is necessary to the eventual improvement of public dental health. Quantitative measurement of disease most commonly relies on "indices." An index is an expression of clinical observations in numerical values. 
Caries epidemiological studies have traditionally been based on clinical examination alone. ,, Several studies have confirmed that the prevalence of proximal caries is significantly underestimated when clinical data are compared with the radiographic information. Radiographs are claimed to be of great importance, particularly for the detection of proximal caries in contacting posterior surfaces. ,,,,,,,,,,,,,, Use of radiographs has resulted in considerable rise in the decayed surface (D-S) and decayed-missing-filled surfaces (DMFS) score , with relatively largest contribution in the teenagers. , However, ethical and budgetary problems as well as time constraints and technical limitations have not always allowed an epidemiologist to routinely use radiographs.  Therefore, research should be aimed at gathering more information about the precise extent of underestimated proximal dental caries when only clinical criteria is used and its influence on DMFT and DMFS scores. 
Radiographic multiplication / adjusting / correction factor has been calculated by Mann et al,  to compensate for the clinically undetected proximal caries. The above factor is a numerical value derived by dividing the sum total of the clinically detected caries plus additional radiographically detected proximal caries by the number of caries detected clinically. This value when multiplied by the clinically detected caries in a given population for whom radiographs have not been taken, help to compensate for the clinically underestimated proximal caries to reflect the actual D-S or DMFS score. However, such a factor is dependent on various factors like caries prevalence, age of the participants, average fluoride use in the population, amount of restorative treatment etc. Therefore, it was proposed that correction factors should be determined for various study population. ,,
Thus this study was designed for 16-20 year old subjects in Bagalkot (a place in India with natural fluoridation) to determine:
The additional value of radiographic examination (bitewings) compared to clinical examination in assessing posterior proximal cariesThe radiographic multiplication /adjusting / correction factors and verify its repeatability and thus its usefulness
Materials and Methods
In the period from August to October, 2005, a total of 200 subjects (two groups of 100 each - decided after power analysis) willing to participate in the study were included with no gender preference. The subjects were 16 to 20-year-old students from colleges in Bagalkot as increased efficiency of bitewing radiographs has been reported in teenagers.  Individuals with fixed orthodontic appliance, fixed prosthesis, crowding, and supernumerary or missing teeth in the premolar and molar region were excluded. The study was approved by Rajiv Gandhi University of Health Sciences, Bangalore and written informed consent was obtained from each subject.
A single trained examiner using mouth mirror and probe, performed intra oral examinations with the aid of dental chair light in Group A comprising of 100 subjects. The DMFS index was recorded clinically using the criteria given by Henry Klein, Carrole E. Palmer and Knutson JW in 1938.  Bitewing radiographs of premolar and molar regions (four radiographs each) were taken. Rinn XCP (extension cone paralleling) bitewing instruments and Kodak Ekta speed films were used. The exposure parameters of 70 Kvp, 8 mA and 12-inch focal spot film distance was used with a round collimator and open-ended beam-indicating device.
All the exposed films were processed manually in comparison with a standard reference film mounted in the dark room as the quality of the films processed automatically is not often as high as those carefully developed manually.  To avoid bias the bitewing radiographs were read later without reference to clinical scores. The bitewing radiographs were examined by two trained observers. A particular surface was scored as carious if radiolucency extending more than half way into enamel was present. Caries was recorded only when both examiners agreed. In case of difference of opinion, a senior radiologist's opinion was taken as final. A magnifying lens (2Χ) was used to study the finer details.
Additional proximal caries revealed by the radiograph was determined. The correction factor for D-S and DMFS score was calculated using the formula
where in the corrected D-S/DMFS, score is equal to the sum of clinical D-S/DMFS score and additional proximal caries detected radiographically.
The correction factors for D-S and DMFS score was calculated for group A. To verify its repeatability and thus its usefulness in the study population a second sample of 100 subjects (Group B) within the same age group, place, and exclusion and inclusion criteria were chosen. Clinical and radiographic examinations were performed and correction factors calculated in the above described manner.
The results were statistically analyzed with the use of means, standard deviations, regression equation and "Z" test. Level of significance was determined at P>0.05.
Two hundred subjects, 127 males and 73 females participated in the study. The sample population had a low level of caries experience due to natural fluoridation. A significant number of additional proximal D-S was detected with the help of bitewing radiographs in both groups [Table 1].
The mean caries experience and additional radiographic yield in both groups was almost same [Table 2].
Before applying correction factor, the significance of correlation between clinical and radiographic D-S and DMFS score was ascertained by using regression equation [Corrected D-S = 0.34 + 1.17 (Clinical D-S) and Corrected DMFS = 0.29 + 1.17 (Clinical DMFS)] for each of the 100 clinical D-S and DMFS values in Group A. High correlation was found between mean clinical and mean radiographic corrected D-S and DMFS values [Table 3].
The use of bitewings resulted in 41% and 53% increase in D-S count in Group A and B respectively; the DMFS count increased by 32% and 29% respectively. So the radiographic correction factor for D-S was 1.41 for Group A and 1.53 for Group B. The correction factor for DMFS was 1.32 for Group A and 1.29 for Group B. The difference between them was statistically not significant (P>0.05), thus verifying the repeatability of the radiographic correction factor in this study population.
It is a well documented fact that in caries evaluation radiographs are of great importance, particularly for the detection of proximal caries in contacting posterior surfaces. ,,,,,,,,,,,,,, Further, in routine epidemological research in which no additional diagnostic aids like bitewing radiographs are used, reference is usually made to the possible under evaluation of the presence of proximal caries. , However, for both research purpose and need assessments it is beneficial to have a more accurate figure of the D-S and DMFS. 
This study was undertaken to quantify the additional radiographic yield in proximal caries detection and to find a means to obtain a more precise estimate of caries prevalence in a particular study population without having to subject all individuals to radiographic examination.
In this study, a significant number of clinically undiagnosed proximal caries was detected thus confirming the value of bitewing radiographs in proximal caries diagnosis. The additional radiographic yield was 193.33% and 335.29% in group A and B respectively. Studies by Blaney JR and Greco JF,  Kidd EA and Pitts NB  Pitts NB,  Poorterman et al,  have reported additional radiographic yield ranging from 40% to 700%. This variation in the additional radiographic yield is due to difference in the caries prevalence, clinical and radiographic caries diagnostic threshold used, water fluoridation, age group examined, examination equipment etc.
The radiographic correction factor calculated is dependent on the additional radiographic yield which in turn is dependent on the above mentioned factors. In this study the radiographic correction factor for DMFS score was 1.41 and 1.53 for Group A and Group B respectively. In studies by Mann et al. and Poorterman et al,  the radiographic correction factor ranged from 1.20 to 2.0 emphasizing on the dependence of the calculated factor on the additional radiographic yield.
The limitation of the study is that derived radiographic correction factor is valid only in that particular population and age group for whom it is calculated. However, multicentric studies can be undertaken to check whether similar age group subjects having same DMFS and D-S score from different places will have similar additional radiographic yield and thus common radiographic correction factor. Further the radiographic correction factor has to be recalculated every few years keeping in mind the changing caries prevalence due to preventive programs undertaken in the community.
Radiographs provide additional diagnostic yield when compared to clinical caries examination alone. The calculated radiographic correction factor was found to be repeatable thus can be used to provide a more accurate estimate of caries prevalence without having to subject all individuals to radiographic examination. However, even radiographs are known to miss out some carious lesion. So when other methods which provide better proximal caries detection than bitewing radiograph becomes widely available, then they can be used to compute a correction factor.
We thank Dr. Mangala Meti, Dr. Surekha R, Dr. Rajashekhar, Dr. S. Jayadev and Mr. D.K. Sangam for their help in carrying out this study. We also thank Dr. Vishal Saxena, Dr. Neelkant Patil, Dr. Sathyaprakash, Dr. Santosh Patil, Dr. Steven Rodrigues, Dr. Praveenkumar Mandroli and Dr. Soumya BG for valuable contribution.
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