Third permanent molars, what should orthodontists do?

orthodontics In summary

Join me for a podcast summary looking at the grey topic of lower third molar management. The podcast explores the different guidelines of removal, factors for consideration for removal as well as the effect orthodontics can have on third molar pathology. The lecture was given by Flavia Artese at this year’s British Orthodontic Conference in my city London.

Flavia Artese began with asking the clincal question we face, what would you do with an impacted 3rd molar?

Difference in international practice

· UK NICE guidelines 2000: Surgical removal of impacted third molars should be limited to patients with evidence of pathology

· AAOMS White paper USA 2016: currently or likely to be non-functional associated with disease or at a high risk of developing disease

What factors in decision making

1. Eruption path

· Mandible = mesial, whereas Maxilla = distal

o Rate of impaction Mandible 25%, maxilla 14% Worthington 2016

2. Mechanism of tooth eruption – explained by Frazier-Bowers

· A pathway created by the dental follicle

o Triggers eruption of intraosseous eruption

o Genetic control of cell differentiation in dental follicle

§ Requires root elongation, vascular pressure and DL ise 2008

Orthodontic influence = SPACE

· Decrease with distal movement of posterior teeth

o Distalisation, elastics

§ Kim 2014 = limit of lower molar distalisation

§ 35% of cases already have contact with lingual cortical plate

· Increase through mesial movement

o 80% of 3rd molars erupted in premolar extraction cases Kim 2003

o Increase in retromolar area

o 2nd molars – removal of guidance = unpredictable alignment of 3rd molars, tipped, therefore will likely require orthodontic alignment Gooris 1990

§ Flavia suggested if 7s impacted, removal of 8s and 2nd molar uprighting, as no delay until full root development

Prediction method

· Mandibular morphology

o Longer the mandible = greater chance of 3rd molar eruption: Begtrub 2012

· Retromolar space

o OPG - size of crown and space available: If space greater then size of the tooth = 75% eruption, if less space available than the tooth size = 75% of impaction Olive

Prediction of orthodontists and surgeons Bastos 2016

· Orthodontists 38% extract

· Surgeons 50% extract

· Surgeons extract more

o Surgical morbidly 10% Yamada 2022

o Greater pathology: 82% when erupted, 74% in soft tissue, bone 33%

Surveillance protocol

· No complaints from patients

Fully erupted

· No consensus of protocol pathology

Review of guidelines Gadiwalla 2021

Only 2 guidelines were recommended , RCS and SIGN

· Recommended guidelines

Conclusion

· Limited evidence

· Orthodontists can influence the space

· If second molars require extraction, will require time to erupt as well as

· CBCT should be used for diagnosis

· Refer to oral surgeon for assessment of difficulty in removal

Please join Flavia Artese at the 2025 International Orthodontic Conference in Rio De Janeiro

Contributions

Contents: AbdAllah Sharafeldin

Contents edited and produced: Farooq Ahmed