The story of Leong’s premolar (Dens Evaginatus)

Dr. Rosalind Ho BDS (S’pore) MFGDP (UK)

Leong’s premolar refers to the projected part or a bump/tubercle on the biting surfaces of permanent premolars.

It may occur on the molars, canine, and incisor teeth but is rare.

It is composed of enamel over a dentine core and there is an extension of the pulp horn containing nerves and vessels.

If this structure fractures off, the pulp may be exposed and becomes infected, even necrotic resulting in pain or abscess formation.

It is a developmental anomaly and the patient may not be aware of it until he or she develops pain.

Features;

1 it may occur unilaterally or bilaterally
2 seen more frequently in Asians
3 more frequent in mandibular teeth than maxillary teeth
4 may be seen in some syndromes like Sturge Weber syndrome, etc

Implications;

1 Extra cusp may wear off or fracture causing tooth infection
2 It may cause interference during biting
3 Joint pain may be experienced related to the trauma in 2
4 It may irritate the tongue as it becomes sharp on wearing off.

Management;

If asymptomatic or there is no pain, no treatment is needed.
Preventive measures
1 Oral hygiene care
2 Application of fluoride on the reduced cusp
3 Remove the structure slightly and apply composite
resin to reinforce the surface
4 Reduce the opposing tooth slightly to minimize wear

If there is pain,
Root canal treatment is indicated for adult teeth.
For young teeth where the tips of the roots are not fully formed, MTA pulpotomy may be carried out to save teeth.

Conclusion:

During the check-up, the dentist would highlight the presence of Leong’s premolar teeth so that pro-active steps may be taken to prevent potential problems resulting in root canal therapy.

For further interest on Leong’s premolar, please click on the following article https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1834-7819.1998.tb00183.x