Matti Rajala’s research while affiliated with University of Helsinki and other places

The purpose of this study was to evaluate the reproducibility of the Periodontal Treatment Need System (PTNS), when plaque retentions were examined separately. A sample of 8000 persons was drawn to represent the Finnish population aged 30 yr and over. The first clinical examination (total sample) was made by a specially trained expanded-duty dental auxiliary (EDDA). During the second examination (2-6 months later), 20% of the total sample was reexamined by a dentist, and of those, every 6th patient was examined by the EDDA. Reproducibility of the PTNS was assessed as intra- and interexaminer agreement and was calculated using Cohen's kappa and weighted kappa. The intraexaminer weighted kappa values were 0.67 +/- 0.05 for the PTNS and 0.48 +/- 0.15 for plaque retentions. The interexaminer weighted kappa values between the PTNS registrations were 0.77 +/- 0.05 and 0.74 +/- 0.12 in plaque retentions when examinations were made within 1 day, and 0.53 +/- 0.05 and 0.37 +/- 0.07, respectively, when the interexaminer registrations were made with an interval of 2-6 months between them. The kappa values for intra- and interexaminer reliability reflect quite high reproducibility.

Nyyssönen V (Institute of Dentistry, University of Kuopio, PO Box 138, 70101 Kuopio 10, Finland), Pauniol, Rajala M and Vehkalahti M. Dental caries in the adult population in Finland. International Journal of Epidemiology 1984, 13: 486–490. The aim of this study was to describe the prevalence of untreated dental caries in the adult population aged 30 years and over in Finland according to sex, age, region of living, and socioeconomic status. The level of untreated caries per subject also was studied and population estimates were made for prevalence and level of untreated caries. The representative sample used in this study included 5028 dentate subjects. Data were collected using interviews and clinical examination. The prevalence of untreated caries was 55% in women, and the figure for men was 67%. In eastern Finland the figures for women and men differed significantly. The mean number of decayed teeth was 2.5 per person. Men had more decayed teeth per person than women did. The number decreased significantly with increasing socioeconomic status. The data presented in the study provide a reliable picture of the occurrence of untreated dental caries in Finnish adults arid form the basis for further analyses.

A representative sample of Finnish denture wearers (n = 3875) aged 30 or over were examined clinically and interviewed about their oral hygiene habits, use of dental services and possible prosthetic treatment during last visit to a dentist. Of these denture wearers, over 80% brushed their dentures at least once a day, and 16% visited a dentist at least once in 2 yr. For denture stomatitis the age-standardized risk ratio decreased with brushing frequency in women and increased in men. For frequency of dental visits the prevalence of denture stomatitis increased in both men and women when visits were made over 2-yr intervals. The prevalence of denture stomatitis was higher in the group with dentures over 1 yr old. It seems that the oral hygiene measures as they are generally carried out and regular dental visits are not effective enough methods in preventing denture stomatitis.

The need for complete denture treatment was compared to utilization of complete denture services. To estimate the need for complete denture treatment we used data from the Mini-Finland Survey which included 3620 persons who were edentulous in one or both jaws. Data about utilization of services was obtained through questionnaires sent to samples of dentists and special dental technicians. Utilization of services was 21.8% of the need assessed with professional criteria and 17.7% of the subjective need. Compared to the subjectively assessed need, utilization of complete denture services was highest among young women and lowest among men aged 60-69 yr. Subjective need for denture services was highest in older groups. From these results we conclude that certain barriers prevent patients from seeking care; and as these barriers are reduced, use of complete denture services may increase.

Of a representative sample of 8000 persons aged 30 and over living in Finland, 3875 users of removable dentures were examined. The condition of the oral mucosa was recorded during clinical examinations. The prevalence of oral mucosal lesions associated with removable dentures was analyzed according to age, sex, place of residence, geographical region of living, and type and location of prosthesis. Lesions were found in about 50% of the denture wearers. Women were affected more often than men. The prevalence of lesions decreased with age and differed slightly according to region of living and place of residence. Compared with the wearing of partial dentures, wearing complete dentures increased the risk of lesions. Only one of the 72 denture users who wore a denture with metallic base plate had oral mucosal lesions associated with wearing a denture.

The aim of this study was to analyze the factors that affected the choice between public and private dental services in 1979, when 9% of adults had received their dental services in a public health center. In September 1979 the National Board of Health conducted a telephone interview among Finnish adults over 15 yr old. When a representative sample of 1992 adults was drawn, the response rate was 90.4%. All subjects over 17 yr of age who had used dental services within the last 5 yr were included in the study, making a final sample of 1368. According to the logistic function, the greatest differences were between rural and urban areas. Of the subjects living in urban areas, 18% had visited public health centers; and of those living in rural areas, 45% had visited health centers. Of the adults living in an urban setting, 70% and in rural areas 49% visited private dentists. Of the subjects who had used private dental services, nearly half were managers and upper white-collar workers; while of those using communal services, less than one third worked in such jobs. In urban areas managers and upper white-collar workers used private services twice as often as they used public services. In an urban setting, subjects who had visited a dentist during the last 2 yr had received treatment mainly in the private sector; and in a rural setting, subjects had been treated mainly in health centers.

From a representative sample of 8000 persons aged 30 yr and over, 7190 were examined clinically. Thirty-one percent were edentulous, 23% of the men and 38% of the women. Results of our study were compared with seven other nationwide studies of edentulousness in Finnish adults made during the last decade. For subjects 35-64 yr old the rate of edentulousness was lowest in our clinical study. For those over 64 yr old the rates of edentulousness varied from 54% to 67%. In general, results obtained using interviews or questionnaires gave higher percentages for edentulousness than did the clinical study. Statistical evaluation of the differences in rates found in these studies did not show edentulousness to be either increasing or decreasing in Finland during the 1970's.

The aim of this study was to analyze the present state of occupational dental care in Finland. In addition, the viewpoints of employees and employers concerning possibilities for developing occupational dental care were evaluated. Five percent of employers had arranged dental services for their employees. Twenty-four firms either had their own dentist or had made an agreement with a dentist about dental care for their employees. Most of these dentists delivered all kinds of dental treatment to employees, and the costs of treatment were usually paid from the worker's sickness benefit funds. Many such funds also subsidized the costs of dental treatment delivered in other dental offices. In 1978 about 49% of the workers covered by such funds received subsidies for their dental expenses. The most important means of developing adult dental care in Finland was considered to be widening the scope of public dental care. The second means was widening the scope of the national health insurance system. In third place, the employers supported development of private dentistry. Employees, however, preferred to include dental care in agreements made by collective bargaining.

A sample of 8000 persons was drawn to represent the Finnish population aged 30 years and over. The participation rate was 89.9%. Root caries was recorded when the lesion was obviously soft and more than half of it was located on cementum. Lesions adjacent to fillings were not included. The reproducibility and the standard of the clinical recordings were tested by reexamining 20% of the studied population 2-6 months after the first clinical examination. The overall prevalence of root caries was 21.6% for men and 14.5% for women. The prevalence increased for both sexes almost consistently with age. Root caries was found 1.6 times more often among men than women. Among men 2.23% and among women 1.19% of teeth were affected by root caries.