Ronald J. Hunt

Percent Agreement, Pearson's Correlation, and Kappa as Measures of Inter-examiner Reliability

Percent agreement and Pearsons correlation coefficient are frequently used to represent inter-examiner reliability, but these measures can be misleading. The use of percent agreement to measure inter-examiner agreement should be discouraged, because it does not take into account the agreement due solely to chance. Caution must be used in the interpretation of Pearsons correlation, because it is unaffected by the presence of any systematic biases. Analyses of data from a reliability study show that even though percent agreement and kappa were consistently high among three examiners, the reliability measured by Pearsons correlation was inconsistent. This study shows that correlation and kappa can be used together to uncover non-random examiner error.

Edentulism and oral health problems among elderly rural Iowans: the Iowa 65+ rural health study.

A household health interview survey of 3,673 noninstitutionalized people aged 65 and over in two rural Iowa counties included questions about loss of teeth, use of dentures, and presence of oral health problems. Edentulism rates were 10-15 per cent lower than those found a decade earlier in national health surveys. A log-linear analysis found that the best demographic predictors of edentulism were education, age, and marital status. Spouses tended to be of similar dentition status, i.e., both edentulous or both dentate. No association was found between the loss of teeth and prevalence of digestive problems. Only 7 per cent of the edentulous people felt they needed to visit a dentist, even though 70 per cent had not seen one for over five years. About 40 per cent had dentures that were over 20 years old, with half of these being over 30 years old. Many dentures were loose and causing soreness in the mouth or difficulty in eating. These elderly people appeared to expect some problems with dentures and oral pain and accepted them without feeling a need to seek treatment.

Incidence of tooth loss among elderly Iowans.

This study investigated the 18-month incidence of tooth loss in a random sample of 451 dentate noninstitutionalized Iowans aged 65 and older residing in two rural counties. They had a mean of 19.0 teeth at baseline and lost an average of 0.4 teeth during the subsequent 18 months. Twenty-one per cent of the population lost at least one tooth. Four people had all their teeth extracted. Of the teeth present at baseline, 1.9 per cent subsequently were extracted. The highest incidence of tooth loss occurred among mandibular molars (3.7 per cent), followed by maxillary premolars and canines (3.1 per cent each). The best predictors of tooth loss were previous coronal and root caries.

Effect of Retainer Margin and Distribution of Mercury on Dental Amalgam Mercury Vaporization Patterns

The results of this study showed that mercury vaporization patterns were not related directly to specimen postset mercury distribution. During the setting process, amalgam specimen retainer configurations affected these patterns significantly.