Clinical Oral Investigations

, Volume 23, Issue 3, pp 1015–1022 | Cite as

What kind of third molars are disease-free in a population aged 30 to 93 years?

  • Irja VentäEmail author
  • Miira M. Vehkalahti
  • Anna L. Suominen
Original Article



The aim of the study was to characterize third molars that have remained disease-free in a representative sample of the Finnish population aged 30 years and older.

Materials and methods

Two-staged stratified cluster sampling (N = 8028) was used, and 6005 subjects participated in a clinical oral examination and panoramic radiography. Disease-free third molars were characterized as follows: no dentinal caries, no filling, periodontal pocket depths of neighboring second molars less than 4 mm, and no radiographic pathological findings. Logistic regression analyses served for assessment of the strength of characteristics of third molars for disease-free status.


Of the subjects, 2653 (44%) had at least one third molar. Of them, the majority (62%) had only diseased third molars, 16% had only disease-free ones, and 22% had both. Participants had in total 5665 third molars; 29% of them were disease-free. Female gender, higher level of education, and younger age were related to disease-free status (P < 0.001). Disease-free status was more likely for third molars at cervical or apical level than at occlusal level: odds ratio was 10.1 for all teeth, 8.5 for maxillary teeth, and 6.2 for mandibular teeth.


A third molar situated deeper in the bone was more likely to be disease-free than a tooth at occlusal level in the population aged 30 years and older.

Clinical relevance

Our results suggest that the number of disease-free third molars decreased with increasing age, and most dramatically, this occurred among teeth at cervical level with the neighboring second molar.


Third molar Pathology Adult population Epidemiology Panoramic radiograph 



Planmeca Oy placed digital panoramic X-ray apparatus and software at our disposal during the survey.


Field surveys were organized by the National Institute for Health and Welfare (THL) in Finland and partly funded by the Finnish Dental Society Apollonia and the Finnish Dental Association. The first author received a grant for this study from the Finnish Association of Women Dentists.

Compliance with ethical standards

Conflict of interests

The authors declare that they have no conflict of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.


  1. 1.
    Bouloux GF, Busaidy KF, Beirne OR, Chuang S-K, Dodson TB (2015) What is the risk of future extraction of asymptomatic third molars? A systematic review. J Oral Maxillofac Surg 73:806–811CrossRefGoogle Scholar
  2. 2.
    Suominen-Taipale L, Nordblad A, Vehkalahti M, Aromaa A (eds) (2008) Oral health in the Finnish adult population. Health 2000 Survey. Publications of the National Public Health Institute B25/2008, Helsinki Finland 2008. Accessed 28 May 2018
  3. 3.
    Magraw CBL, Moss KL, Fisher EL, Offenbacher S, White RP Jr (2016) Prevalence of visible third molars in the United States population: how many individuals have third molars? J Oral Maxillofac Surg 74:13–17CrossRefGoogle Scholar
  4. 4.
    Golden BA, Baldwin C, Sherwood C, Abdelbaky O, Phillips C, Offenbacher S, White RP Jr (2015) Monitoring for periodontal inflammatory disease in the third molar region. J Oral Maxillofac Surg 73:595–599CrossRefGoogle Scholar
  5. 5.
    Kinard BE, Dodson TB (2010) Most patients with asymptomatic, disease-free third molar elect extraction over retention as their preferred treatment. J Oral Maxillofac Surg 68:2935–2942CrossRefGoogle Scholar
  6. 6.
    Ventä I, Vehkalahti MM, Huumonen S, Suominen AL (2017) Signs of disease occur in the majority of third molars in an adult population. Int J Oral Maxillofac Surg 46:1635–1640CrossRefGoogle Scholar
  7. 7.
    National Institute for Health and Welfare (2017) Population studies. Health 2000-2011 Surveys. National Institute for Health and Welfare, Finland 2017. Accessed 28 May 2018
  8. 8.
    Aromaa A, Koskinen S (eds) (2004) Health and functional capacity in Finland. Baseline results of the Health 2000 Health examination survey. Publications of the National Public Health Institute B12/2004. Helsinki, Finland 2004. Accessed 28 May 2018
  9. 9.
    Heistaro S (2008) Methodology report. Health 2000 Survey. Publications of the National Public Health Institute B 26/2008. National Public Health Institute. Helsinki, Finland 2008. Accessed 28 May 2018
  10. 10.
    Nunn ME, Fish MD, Garcia RI, Kaye EK, Figueroa R, Gohel A, Ito M, Lee HJ, Williams DE, Miyamoto T (2013) Retained asymptomatic third molars and risk for second molar pathology. J Dent Res 92:1095–1099CrossRefGoogle Scholar
  11. 11.
    Pell G, Gregory B (1933) Impacted mandibular third molars: classification and modified techniques for removal. Dent Digest 39:330–338Google Scholar
  12. 12.
    Ventä I, Murtomaa H, Turtola L, Meurman J, Ylipaavalniemi P (1991) Assessing the eruption of lower third molars on the basis of radiographic features. Br J Oral Maxillofac Surg 29:259–262CrossRefGoogle Scholar
  13. 13.
    National Institutes of Health (NIH) (1980) NIH consensus development conference for removal of third molars. J Oral Surg 38:235–236Google Scholar
  14. 14.
    Stanley HR, Alattar M, Collett WK, Stringfellow HRJR, SpiegeL EH (1988) Pathological sequelae of “neglected” impacted third molars. J Oral Pathol 17:113–117CrossRefGoogle Scholar
  15. 15.
    Eliasson S, Heimdahl A, Nordenram Å (1989) Pathological changes related to long-term impaction of third molars. A radiographic study. Int J Oral Maxillofac Surg 18:210–212CrossRefGoogle Scholar
  16. 16.
    Huang H, Mercier P (1992) Asymptomatic impacted teeth in edentulous jaws undergoing preprosthetic surgery. A long term evaluation. Int J Oral Maxillofac Surg 21:147–149CrossRefGoogle Scholar
  17. 17.
    Knutsson K, Brehmer B, Lysell L, Rohlin M (1996) Pathoses associated to third molars subjected to removal. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 82:10–17CrossRefGoogle Scholar
  18. 18.
    Kay LW (1966) Investigations into the nature of pericoronitis. Br J Oral Surg 3:188–205CrossRefGoogle Scholar
  19. 19.
    Fernandes MJ, Ogden GR, Pitts NB, Ogston SA, Ruta DA (2010) Actuarial life-table analysis of lower impacted wisdom teeth in general dental practice. Community Dent Oral Epidemiol 38:58–67CrossRefGoogle Scholar
  20. 20.
    Dodson TB (2012) How many patients have third molars and how many have one or more asymptomatic, disease-free third molars? J Oral Maxillofac Surg 70(Suppl 1):4–7CrossRefGoogle Scholar
  21. 21.
    Miloro M, Dabell J (2005) Radiographic proximity of the mandibular third molar to the inferior alveolar canal. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 100:545–549CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Oral and Maxillofacial Diseases, Faculty of MedicineUniversity of HelsinkiHelsinkiFinland
  2. 2.Institute of DentistryUniversity of Eastern FinlandKuopioFinland
  3. 3.Department of Oral and Maxillofacial DiseasesKuopio University HospitalKuopioFinland
  4. 4.Public Health Evaluation and Projection UnitNational Institute for Health and WelfareHelsinkiFinland

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