Crowding – detailed

➤ Moderate crowding

• Unlike mild crowding in the mixed dentition, which may resolve on its own, moderate crowding is likely to persist.
• Treatment is indicated if lower incisor position is normal to retrusive, lips are normal or retrusive, there is loss of leeway space and/or the arches are constricted (Proffit et al. 2013).
• Treatment is usually an interim measure and the child will likely require a 2nd phase treatment in the full permanent dentition (Proffit et al. 2013).
• There is however a lack of strong evidence on the long term benefits for treating these cases in the mixed dentition.

➤ Severe crowding

• In severe crowding mixed dentition cases, there may usually be other associated problems which also require early treatment – such as a functional shift, pseudo Class III or Class II incisor pattern – and these should be treated accordingly.
• If the severe crowding is the only problem, then planning for future extractions or starting serial extractions may be the only early treatment modality to assist with long term treatment (Proffit et al. 2013).
• A borderline case may best be delayed until the full permanent dentition for treatment so careful extraction patterns can be decided upon.

➤ Early loss of primary canines

• Early loss of primary canines as the lateral incisors erupt is usually a sign of severe crowding (Cobourne and DiBiase et al. 2010)
• The permanent incisors may be well aligned due to the temporary space gained from the C’s exfoliation. This can however be deceptive as it masks a severe crowding appearance.
• If a unilateral primary canine is lost, a balancing (contralateral) extraction of the other primary canine is recommended to maintain midlines (Proffit et al. 2013).
• The treatment indications are similar to severe crowding.

➤ Prevention of crowding

• Early loss of deciduous teeth can lead to arch length decrease (loss of leeway space or primate space). This is an indication for early treatment.
• Supernumeraries/odontomas can lead to displacement and crowding of teeth which require early treatment.

➤ Aesthetic concerns of displaced teeth

• Displaced teeth as a result from crowding can be a significant aesthetic concern to a patient. This is often a primary indication for treatment.

➤ Aesthetic concerns of the crowding

• The appearance of the crowding itself can also be a significant aesthetic concern to the patient. The aesthetic concerns are not necessarily linked to the severity of the problem. (Jolley et al. 2010, Meyer-Marcotty et al. 2010)

➤ Mild to severe crowding

• There is no strict threshold for the treatment of crowding. The IOTN (Brook and Shaw 1989) has defined a mild need at >2mm of crowding, a moderate need at > 4mm of displacement and a severe need at crowding which has caused impaction teeth (apart from third molars).

➤ Trauma to soft tissues

• Displaced teeth due to crowding can cause irritation to the cheeks, tongue or gingiva. In more severe cases this can cause mucosa ulcerations and is a strong indication for treatment.

➤ Trouble maintaining oral health

• Whilst there is an absence of strong population-based evidence between less crowding and better oral health, localised crowding can result in difficulties or impaired cleansability and is associated with increased gingivitis (Macey et al. 2000).
• Correcting the crowding can improve the patient’s quality of life and subsequently motivate them to upkeep better oral health.

➤ Any associated problems requiring treatment

• Associated problems such as increased or decreased overjet, posterior crossbites, a deep bite and/or skeletal malocclusions may be the primary indicator for treatment instead. See associated problems.