Dental Education Lecture: Crack Tooth
Crack tooth has a crack line across the tooth surface (Fig.1 arrowheads). When you bite down hard, the tooth is separating along the crack line, accompanied by pain. When you relieve the biting pressure, the tooth is trying to return its original status. Sometimes the pain is more severe the moment you relieve the bite pressure than when you bite down.
The crack line may be more obvious when the tooth is stained (Fig.2). In early stage of cracking, the tooth looks normal in X-ray (Fig.3). But we need to place a crown to prevent any further cracking. If left unprotected, the cracking may extend to the nerve (Fig.3 black outline), causing spontaneous pain. We have to do root canal. The tooth may be even completely split. We may have to take the broken tooth out.
For the present case, we proceed to make a crown. After crown preparation (evenly removing outer layer of the tooth), the crack line is still visible (Fig.4). However, the patient feels better after placing a temporary crown. Fig.4 is taken after removing the temporary crown, but before placing a permanent crown. We wish the patient doing well after cementing the permanent crown. Sometimes the patient may develop pain after crown placement, because we do not know how deep the crack is relative to nerve.
Xin Wei, DDS, PhD, MS 1st edition 06/06/2010, last revision 12/09/2010