When To Extract An MIH Affected Molar?
This post follows on from the last post How To Restore A MIH Affected Molar. A very important consideration, when presented with a child with MIH, is how to treat them to achieve the most definitive, cost-effective and stress-free result. One treatment is to extract the affected molar(s) and this post will discuss some considerations and indications for this treatment.
The implications of restoring a severely affected first permanent molar (FPM) are significant. Any restoration placed is likely to have a guarded prognosis. Furthermore, as the tooth has entered the restorative cycle it will require more complex and expensive interventions in the future. This could involve several restorations, followed by root canal treatment and crown and several decades later an implant and crown. Overall, a treatment commitment of >$30,000 per tooth. As such, in a child, we can take advantage of growth to achieve an excellent and biological outcome.
What to Consider
When presented with a patient with MIH affected molars, comprehensive oral visual and radiological examinations should be performed. Information that is required includes:
· Medical history of the child
· Severity and extent of affected teeth
o More severely affected are likely to benefit from extractions
o Is the affected tooth/teeth in the maxilla, mandible or both
· Condition of other teeth
· Developmental stage of other teeth, including the presence of 8’s
· Malocclusion
o Presence of crowding or spacing
· Dental Anomalies
· Compliance (1, 2)
Once a comprehensive examination has been performed, an informed decision can be made. If you are considering extractions, we would strongly recommend that an orthodontic consultation is sought. This can help guide the ideal timing and need for balancing (contralateral) or compensating (opposite arch/antagonistic) extraction(s). Furthermore, if there are malocclusion or crowding issues, coordination with orthodontic colleagues can help achieve the best result.
Sourced from: Paediatric Dentistry, 2018, Welbury et al (3)
Timing of FPM Extractions
Extraction prior to the age of 8 years can lead to distal eruption of the premolar and should be avoided if possible (which is not always the case, for example in cases of severe dental breakdown, requirement for a general anaesthetic for treatment…). (1, 4)
There is no confirmed ‘ideal’ extraction time. However, if you are aiming to achieve maximal natural space closure, extraction when the furcation of the 7 has just formed will hopefully allow the greatest closure. Space closure in the maxilla is always more reliable than the mandible and if extractions are delayed, as long as there is still bone overlying the 7, natural space closure should be relatively acceptable. (4, 5) Even if we have extracted at the most ‘ideal’ time, we always let parents know that their child may need orthodontics in the future.
Variations to the ‘Ideal’ Time
In certain cases, it may be pertinent to delay extraction of the FPM. For example, in a Class II Div 1 malocclusion case, delaying a maxillary extraction until further development has occurred can allow for the FPM space to be utilised for orthodontic retraction. (1, 2)
If extractions have been delayed and the 7’s have erupted, natural space closure is very limited. This does not mean extraction(s) should not be considered, but orthodontic closure with consideration for anchorage requirements, will be necessary. Once again, an orthodontic colleague can help you arrive at the best decision for your patient.
Balancing and Compensation Extractions
The requirement to balance or compensate for the removal of the FPM truly depends upon the malocclusion of the patient. For example, if the patient has a Class II Div 1 malocclusion and requires removal of the mandibular FPM, a compensating extraction of a perfectly healthy maxillary FPM may not be required if it is in occlusion with the mandibular E. Conversely, if the patient is a Class I malocclusion, removal of the mandibular FPM will likely result in over eruption of the maxillary FPM and a compensating extraction should be considered. (1,2)
A Class II Div 1 Malocclusion, with #26 occluding on #75. Extraction of #36 is less likely to result in over-eruption of #26.
To avoid making this post overly lengthy, we have highlighted a guideline and an article in the references that discusses in more detail some considerations for balancing and compensating extractions as well as the timing of extractions.
Summary
Extraction of a compromised FPM should be considered in children and adolescents. Restoring a compromised FPM at a young age can leave the child with a considerable lifelong burden. Taking advantage of growth and development may result in an excellent outcome with the 7’s and 8’s in functional occlusion and negate the requirement for later wisdom teeth extraction. This is a massive topic and we recommend contacting your paediatric and orthodontic colleagues if you have patients you believe would benefit from this treatment.
All the best
Sarah and Tim
1. Ong DC, Bleakley JE. Compromised first permanent molars: an orthodontic perspective. Aust Dent J 2010;55:2-14; quiz 105.
2. Cobourne MT, Williams A, Harrison M. National clinical guidelines for the extraction of first permanent molars in children. Br Dent J 2014;217:643-648.
3. Welbury R, Duggal MS, Hosey MT. Paediatric Dentistry. Oxford: Oxford University Press, 2018.
4. Saber AM, Altoukhi DH, Horaib MF, El-Housseiny AA, Alamoudi NM, Sabbagh HJ. Consequences of early extraction of compromised first permanent molar: a systematic review. BMC Oral Health 2018;18:59.
5. Wu M, Chen L, Bawole E, Anthonappa RP, King NM. Is there sufficient evidence to support an optimum time for the extraction of first permanent molars? Eur Arch Paediatr Dent 2017;18:155-161.