Clinical Assessment & Presentations
Intra-oral Features
Loss of arch length / crowding
Early loss of primary molars often results in loss of leeway space which causes crowding.
The degree of space loss and crowding is primarily influenced by the age, existing crowding and tooth position in the arch (Cobourne and DiBiase 2010).
The earlier the primary tooth is loss the more potential for loss of arch length. Loss of arch length also increases if there is already crowding in the dental arch. There is generally more space loss in the maxilla than mandible. The loss of Es will often cause more first permanent molar drifting than the Ds. The loss of Cs will often cause more midline deviation than the Ds (Crawford et al. 2008).
Loss of arch length can be prevented by maintaining the space. Despite the applications of many different types of space maintainers, it must be acknowledged that the best space maintainer is actually the primary tooth itself. Therefore in patients who have a high risk of space loss, every attempt should be made to maintain the primary tooth if possible (i.e. prevent the need for extractions by intervening on dental caries/pathology early). If extraction of a primary tooth is warranted then a space maintainer appliance is recommended to prevent loss of arch length and future crowding. The longevity of the space maintainer and oral hygiene are key considerations to whether a patient will have effective space maintenance (Proffit et al. 2007). A specialist orthodontist consult to assess the child’s complete facial, skeletal and dental relationships is recommended to determine the usefulness of the space maintainer.
Midline shifting
Early loss of canines or at times the first primary molar can cause a dental midline shift. Primary canines are rarely loss, and if they do become exfoliated early by the lateral incisor’s eruption it is a sign of severe future crowding. A unilateral loss will cause significant midline deviation and a balancing extraction of the contralateral primary canine is warranted to maintain incisor symmetry (Royal College of Surgeons Guideline 2006).
Malocclusion and ectopic teeth
The loss of arch length will cause a molar or canine malocclusion. It can also cause ectopic teeth to develop, such as palatally or lingually ectopic premolars due to the loss of leeway space. Early loss of lower deciduous teeth may cause supra-eruption of the upper teeth.
In the above figure, the early loss of an upper E causes mesial drifting of the upper first permanent molar which reduces leeway space and arch length. This causes a Class II molar relationship to develop. Because of the lack of space, the second premolar is likely to erupt palatally as it deviates from its normal eruption path.
