Dental Education Lecture: Central Cusp Infection Treatment
As we discussed in the last lecture, the nerve becomes infected and causes root tip infection (red, Fig.1) after the central cusp is snapped off. What we need to do is to remove infected nerve inside the tooth and let root tip infection heals by itself.
First of all, we need to open up the infected nerve (Fig.2) and remove the latter (Fig.3). By diligent cleaning, the root canal (actually a tube inside the tooth) is basically free of debris and germs. After this, a strong alkaline paste is placed inside the tooth (yellow, Fig.5) and sealed with cotton (pink) and temporary filling (gray). The alkaline paste can further kill remaining germs and clear the root tip infection (light blue, Fig.6). The paste also promote root tip closure (dark blue, Fig.7). The doctor may need to change the dressing every one or two months until the root tip is close.
The closure of the root tip makes it possible to fill the root canal tight by condensing the top of filling material (brown, Fig.8). Without the closure of the root tip, root canal filling may be pushed out the root tip (Fig.9). In fact the filling material is not tightly contacting the wall of the root canal, leaving a space (green, Fig.9). The space may invite the germ to grow and causes re-infection inside the tooth (black, Fig.10) and in the root tip (red) after a permanent filling is placed (gray).
Therefore, root canal treatment for central cusp infection is not easy. Adults should bring the kid to the office several times without delay or hesitation even though it appears that the kid is out of pain.
Next lecture will show us a case of successful treatment of central cusp.
Xin Wei, DDS, PhD, MS 1st edition 07/04/2009, last revision 07/05/2009