Caries experience among adults in Northern Finland -association with oral hygiene and genetic factors

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

Markku Larmas lecture hall (H1091), Dentopolis, Oulu

Topic of the dissertation

Caries experience among adults in Northern Finland -association with oral hygiene and genetic factors

Doctoral candidate

DDS Anne Laajala

Faculty and unit

University of Oulu Graduate School, Faculty of Medicine, Research Unit of Population Health

Subject of study



Docent Kaisu Pienihäkkinen, University of Turku


Professor Marja-Liisa Laitala, University of Oulu

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Tooth decay among adults in Northern Finland

Tooth decay, i.e. caries, among adults seems to be associated with poor tooth brushing quality, high caries experience and genetics.

Caries is a process in which acids produced by bacteria dissolve minerals from tooth surface. When demineralization-remineralization – balance favours demineralization, an early caries lesion will form. If such situation continues, a caries lesion will proceed deeper in the tooth tissue. Caries lesions can be arrested depending on their stage either by improved self-care or by filling the caries cavity.

This doctoral thesis consists of four scientific papers. The study population consists of adults in the Northern Finland (Northern Finland Birth Cohort 1966). It examines prevalence of caries and its association with behavioural factors as well as previous caries experience. The discovered associations were used to generate a questionnaire for screening caries risk and restorative treatment need. Finally, genetic variations associated with caries were examined. The study was conducted in the department of Population health in the University of Oulu.

Main results were that early caries lesions were prevalent in nearly all participants, while a little less than half had more extensive lesions. Early caries lesions were most often among those participants who had high amount of plaque on their teeth and whose teeth were heavily filled. The generated screening questionnaire for the estimated need for caries treatment, performed well. The genetic study revealed few genetic variations associated with extensive caries lesions. The genetic variations were different among men and women.

This study adds knowledge about caries of adults and factors associating with it. According to the results, dental professionals should pay special attention to maintaining oral health of their male patients who already have had high number of dental fillings, have poor brushing quality and who have extensive caries lesions.
Last updated: 23.1.2024