The benefit of Ramfjord teeth to represent the full-mouth clinical attachment level in epidemiological study

Background: Since the periodontal disease Index of Ramfjord (Ramfjord index) can potentially shorten the examination time by almost half, many studies evaluated Ramfjord teeth in predicting full-mouth periodontal status of an adult population. The aim of this study was to evaluate the benefit of Ramfjord teeth in predicting the fullmouth clinical attachment level of an adult population in patients attending the college of dentistryBaghdad University. Materials and methods: The study participants were 100 patients with age range from 30-60 years old which represent group zero. The patients were divided into three main groups according to the age of the patients. Group I and group II each of them composed of 30 patients while group III composed of 40 patients. In the first time clinical attachment level (CAL) was measured from the full mouth (FM) and then from the Ramfjord teeth (RT) (teeth number: 16, 21, 24, 36, 41, 44) in all groups. Clinical attachment level (CAL) was measured in millimeters using periodontal probe. Results: The difference in the mean clinical attachment level measured from the full mouth (FM) and Ramfjord teeth (RT) by using paired t test was non significant in all the groups. Also in all groups the correlation coefficient as well as beta coefficient was high. Conclusion: The high agreement between Ramfjord teeth and full mouth CAL confirm the epidemiological validity of Ramfjord teeth to represent the full mouth.


INTRODUCTION
Most survey methods use full-mouth assessment of periodontal diseases, which involves the examination of 4 sites on all present teeth.Data from full-mouth examination are the gold standard for accurate assessment of periodontal disease.However, because of the restraints in time, logistic, and cost of full-mouth assessment, this clinical assessment of periodontal diseases is impractical in epidemiological surveys involving large population samples (1) .Therefore, the programs to examine part of teeth are proposed (2) .
Since the Ramfjord index can potentially shorten the examination time by almost half, Mumghamba et al evaluated Ramfjord teeth in predicting full-mouth periodontal status of an adult population (3) .Partial recording of Indices of periodontitis have long been used in clinical and epidemiological studies to predict full-mouth situation (4) .
(1)Assistant lecturer, Department of Periodontics, College of Dentistry, University of Baghdad Ramfjord index had a strong correlation with the full-mouth index in recording plaque, gingivitis, and other periodontal indicators like the probing pocket depth but due to the site-specificity of periodontal diseases, a part of the teeth does not fully reflect the status of full-mouth teeth (5) .So that different index teeth be selected depending on the purpose of survey so as to not only assesses both the incidence and severity of the disease correctly, but also improve the sensitivity and reduce the bias (6) .

MATERIALS AND METHODS
The patients participated in this study were referred to the department of Periodontics in college of dentistry Baghdad University.The patients include 100 male which represented by group (0).All the patients were suffered from chronic periodontitis which affect people mostly after the age of 30; the samples were divided into three main groups according to the age of the patients in which group (I) include 30 patients with an age range of (30-40) years, group (II) Oral and Maxillofacial Surgery and Periodontics 123 include 30 patients with an age of (>40-50) years while group (III) include 40 patients with an age more than 50 years.
Clinical attachment level (CAL) was measured in millimeters using William periodontal probe with Williams's markings from the cementoenamel junction to the bottom of the pocket/sulcus.The measurements were made at four surfaces of each tooth.The distance was measured indirectly by subtracting the distance from the gingival margin to the cemento-enamel junction from probing pocket depth.In some cases when there was gingival recession, loss attachment was measured by adding the distance from the gingival margin to the cemento-enamel junction to the probing pocket depth.The level of the cemento-enamel junction could be determined by feeling it with probe.
In some situation were the cemento-enamel junction was totally obliterated by:-1.Full crown coverage.
In these situations the tooth was excluded.If the patient had a Ramfjord tooth/teeth missing, he was excluded from the study.In the first time clinical attachment level (CAL) was measured from the full mouth (FM) and then from the Ramfjord teeth (RT) in all groups.The mean CAL per tooth was calculated by summing the measurements per tooth and dividing by the number of measurements.Mean CAL for full mouth was calculated by summing the mean CAL per tooth and dividing by the number of the teeth.While the mean CAL for Ramfjord teeth was calculated by summing the mean CAL per tooth for the Ramfjord teeth (teeth number: 16, 21, 24, 36, 41, 44) and dividing them by the number of the Ramfjord teeth, if the Ramfjord tooth was missing the case was ignored.
The statistical analyses used in this study were a paired t-test to compare the difference in the mean CAL measured from the full mouth (FM) versus Ramfjord teeth (RT).In addition to that Pearson correlation coefficients between the mean CAL calculated from the full mouth measurement and from the Ramfjord teeth were conducted and then a linear regression analysis (β coefficient) with the full mouth mean CAL as the outcome variable and the Ramfjord teeth mean CAL as independent variable were conducted .

RESULTS
Descriptive statistics which include mean and standard deviation of CAL for each group were shown in table (1).
The difference in the mean of CAL measured from the full mouth (FM) and Ramfjord teeth (RT) by using paired t-test were non significant in all the groups as shown in table (2) the p>0.05 non significant.The correlation between the mean CAL calculated from the full mouth and Ramfjord teeth was 0.75 in the 1 st age group and was 0.92 in the 2 nd age group, while it was 0.86 in the 3 rd age group, in the all previous groups the correlation coefficient were strong (+)ve, as shown in the table (3).
We then conducted a linear regression analysis with the full mouth mean CAL as the outcome variable and the Ramfjord teeth mean CAL as the independents variable in each group, the β coefficient for the mean CAL measured by Ramfjord teeth to predict the full mouth was ranged between 0.70 and 1.06, the result were positive for the all groups which mean it is a significant result, as shown in table (4).

DISCUSSION
The study based on CAL measurement in patients have chronic periodontitis of different age groups, the results show non significant differences between Ramfjord teeth and full mouth at different age groups using paired t-test.
The other results show strong (+ve) correlation between Ramfjord teeth and full mouth at different age groups.The beta coefficient which was used to assess prediction of the full-mouth mean CAL by Ramfjord teeth mean CAL was high.The high agreement between Ramfjord teeth and full mouth mean CAL proves the epidemiological validity of Ramfjord teeth to represent the full mouth.This was disagree with Fleiss et al, who found that the Ramfjord teeth are inadequate alternatives of the rest of the mouth for epidemiologic studies of periodontitis (7) , so that the assessment of Ramfjord teeth was not as suitable for evaluation of either disease extent or prevalence (2) .
But this study was in agreement with Mumghamba et al, Silness and Røynstrand, and Najah et al (3,5,8) .They concluded that there is high agreement between Ramfjord teeth and full mouth.
Partial-mouth examinations with appropriate adjustment of Ramfjord index teeth data may be useful for assessing periodontal disease progression in longitudinal population studies of human periodontitis (9) .So these results support the use of Ramfjord teeth procedure to conserve time, limit cost and reduce patient and examiner fatigue, while providing maximal clinical information (2) .