Kurol J, Thilander B Infraocclusion of primary molars and the effect on occlusal development, a longitudinal study. Eur J Orthod. 1984; 6:277-93
Kurol J Infraocclusion of primary molars: an epidemiologic and familial study. Community Dent Oral Epidemiol. 1981; 9:94-102
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Infra-occluded primary molars: diagnosis and management

From Volume 16, Issue 2, April 2023 | Pages 85-90


Trishna Patel

MChD/BChD BSc, MFDS RCPS (Glasg), PGCert

Orthodontic Specialty Registrar 3, Derby and Sheffield

Articles by Trishna Patel

Email Trishna Patel

Catherine A Brierley

BDS(Hons), MFDS RCS, MClinDent, Orthodontic, Post-CCST

Sheffield and Chesterfield, Chesterfield, Derbyshire, UK

Articles by Catherine A Brierley


Infra-occluded primary molars can be challenging in terms of their surgical management and potential sequelae. The prognosis of these teeth needs to considered allowing treatment planning for a stable long-term outcome for the patient. This article outlines the key principles to consider following a diagnosis of an infra-occluded primary molar, and it provides a management tool to aid decision making.

CPD/Clinical Relevance: Timely diagnosis and management of infra-occluded primary molars is vital within the overall care pathway for these patients.


Infra-occlusion is when a tooth has failed to maintain its occlusal level relative to adjacent teeth and is therefore found below the occlusal plane.1 In 1981, Kurol described infra-occlusion as when the occlusal surface of a tooth is 1 mm below the occlusal surface of a fully erupted adjacent tooth.2 The timely management of infra-occluded primary teeth avoids the need for more complex surgical management as well as allows planning for the resultant space. This article highlights the key principles behind management of such cases.

The prevalence of infra-occluded primary molars ranges between 1% and 39%, with mandibular molars being much more affected than maxillary molars.2,3 The incidence is greater the older the patient, with infra-occlusion recorded from the age of 3 years suggesting a cumulative process.3 Bjerklin, however, demonstrated that there was little increase in infra-occlusion after the age of 20 years, suggesting primary molars after this age had a good long-term prognosis.4 There also appears to be equal frequency in males and females, as well as the site of occurrence.

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