University of Oulu

Närhi, L., Tolvanen, M., Pirttiniemi, P., & Silvola, A.-S. (2022). Malocclusion severity and its associations with oral health-related quality of life in an adult population. European Journal of Orthodontics, 44(4), 377–384.

Malocclusion severity and its associations with oral health-related quality of life in an adult population

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Author: Närhi, Linnea1; Tolvanen, Mimmi2; Pirttiniemi, Pertti1;
Organizations: 1Department of Oral Development and Orthodontics, Oral Health Sciences, Faculty of Medicine, University of Oulu, Medical Research Center Oulu (MRC Oulu), Oulu University Hospital, Finland
2Center for Life Course Health Research, Faculty of Medicine, University of Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.4 MB)
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Language: English
Published: Oxford University Press, 2022
Publish Date: 2022-12-07


Aim: The aim of this study was to investigate malocclusion severity and its associations with oral health-related quality of life (OHRQoL) among middle-aged adults.

Materials and methods: The study material consisted of 1786 subjects from the Northern Finland Birth Cohort 1966 who attended dental and oral examination as part of the 46-year-old follow-up study. Malocclusion severity was assessed using the Dental Health Component (DHC) of the Index of Orthodontic Treatment Need (IOTN) and the Peer Assessment Rating index (PAR) from digital 3D dental models. Participants also answered a questionnaire including the Oral Health Impact Profile (OHIP-14) and a question on their satisfaction with occlusal function. Differences between malocclusion severity groups were evaluated for both genders separately. For adjusted models, multivariate Poisson regression models were conducted.

Results: In this study population, 31.3% had great or very great orthodontic treatment need according to DHC and the mean PAR total score was 22.05. The most severe malocclusions were associated with OHRQoL, especially the psychosocial and handicap dimensions, and satisfaction with occlusal function. There was a significant difference between genders, men having more severe malocclusion but women reporting more OHRQoL impacts.

Conclusion: One third of the study population were considered to have severe malocclusion. There was an association between malocclusion severity and OHRQoL in adult population, particularly in women.

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Series: European journal of orthodontics
ISSN: 0141-5387
ISSN-E: 1460-2210
ISSN-L: 0141-5387
Volume: 44
Issue: 4
Pages: 377 - 384
DOI: 10.1093/ejo/cjab070
Type of Publication: A1 Journal article – refereed
Field of Science: 313 Dentistry
Funding: This study was supported by the Finnish Dental Association Apollonia, Finnish Cultural Foundation and Finnish female dentists (to L.N.). NFBC1966 received financial support from the University of Oulu, grant no. 24301140, and ERDF European Regional Development Fund, grant no. 539/2010 A31592.
Dataset Reference: NFBC data are available from the University of Oulu, Infrastructure for Population Studies. Permission to use the data can be applied for research purposes via electronic material request portal. In the use of data, we follow the EU general data protection regulation (679/2016) and Finnish Data Protection Act. The use of personal data is based on cohort participant’s written informed consent at his/her latest follow-up study, which may cause limitations to its use. Please contact NFBC project centre ( and visit the cohort website ( for more information.
Copyright information: © The Author(s) 2021. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.