Dental Education Lecture: Crack Tooth Involving Nerve
Earlier, we discuss crack tooth. If the crack does not get into nerve, we just need a crown to hold the tooth in one piece.
When crack extends to nerve, we have excruciating pain. To solve problems, we need to do root canal (to take out pain), crown build-up (a type of filling to close a hole for root canal) and crown.
This happens to Mrs. Hutton's back tooth. After root canal and crown build-up, excruciating pain subsides promptly. In one week, we are preparing the crack tooth for crown. Before taking impression, photos are taken to show crack line (arrowheads in Fig.1). For orientation purpose, C denotes cheek side of the crack tooth, whereas T stands for tongue side. Black arrowhead points to the back portion of the crack line; white arrowhead points to the front portion of the crack line. Before crown build-up (white filling, W in Fig.3), the two portions of the crack line is connected, as shown by a black line in Fig.2. Before treatment, the crack tooth tends to separate as shown by two arrows in Fig.2 when Mrs. Hutton bites on something hard. After root canal, the white filling (W in Fig.3) holds the two separate portions together internally (from inside). But this is not enough. We need a crown (a cap) to hold the tooth together externally (from outside: Tooth Repair Fig.5). Let us tilt the bottom of Fig.1, 2, or 3 a little up to show the back portion of crack line a little better (Fig.4). It appears that after tooth preparation, the crack line is inside of the confinement (border) of the crown (as demonstrated by 4 arrowheads). In other word, the crown appears to completely cover and seal the crack line. The chance of nerve re-infection is decreased. We are going to discuss reasons behind crack tooth next.
Xin Wei, DDS, PhD, MS 1st edition 08/10/2010, last revision 08/25/2010