Dens Invaginatus
Investigating Invaginatus
I recall a paediatric lecture at uni when I first heard about Dens Invaginatus – the ‘tooth within a tooth’ and thinking that was crazy! In my first decade as a general dentist I don’t ever recall seeing one or diagnosing one - at least no severe ones (in retrospect, I’ve probably seen dozens of mild Class I’s). Given that the prevalence is around 4% in the general population, and that I’ve now seen a few pop up in the last few years, I thought it a good time to review the classification and treatment options. I hope you find them useful too.
What is Dens Invaginatus?
Dens invaginatus is a developmental dental anomaly, most commonly affecting permanent lateral incisors, but can occur in other teeth (though presentation in primary dentition is extremely rare). It occurs when the hard tissue within the cingulum pit is turned in on itself, and often includes some pulpal tissue. This leads to a situation where there is very little tooth between the oral cavity and the pulp, or even a groove that allows direct passage for bacteria and can result in rapid caries/ necrosis and infection soon after eruption of the tooth.
Classification – note the potential for bacterial movement in each example.
Image source: Gallacher, A., Ali, R. & Bhakta, S. Dens invaginatus: diagnosis and management strategies. Br Dent J 221, 383–387 (2016).
Diagnosis
Diagnosis is the key and if you can diagnose them early, you can help to prevent complex issues from developing, such as necrosis. Simple management such as a sealant can handle most of these cases.
Clinical Observations
· Palatal pit/groove noted after eruption of tooth.
· Anatomical anomaly such as barrel shaped tooth or dilated crown.
· Labial groove and incisal notch (more common for central incisor)
Radiographic Observations – may be a chance finding on radiographs taken for other purposes such as trauma. Indications can be seen on intra-oral and extra-oral 2D imaging. In appropriate cases, this may prompt the order for detailed 3D imaging such as a CBCT to fully understand the anatomy of the affected tooth/teeth.
Conclusion
Early detection of a Dens Invaginatus is crucial to help to avoid future complications. At 4% you will be surprised how many you see if you start looking!
We hope this have been helpful. Erica and Tim