Dental Education Lecture: Internal Bleaching at Home
Both external and internal bleaching can be done at home. The former is straightforward, whereas the latter needs special instruction. Internal bleaching is done after root canal therapy. Fig.1 is front view of two upper central incisors. The one that needs to be whitened internally is shown as gray. Let us turn the tooth 90 degrees so that the buccal (B, near the cheek/lip) surface is on your left-hand side and the lingual (L, next to your tongue) on your right hand side (Fig.2). Then make a cross cut so that you can see what the dentist has done for the darkened tooth (Fig.3). He has finished root canal filling (brown) and cut it below the gum line (arrowhead) to leave an ample space for internal bleaching. The space is packed lightly with cotton pellet (pink circles) and closed with temporary filling (blue). Root canal filling material needs one or two days to set, to be firm and to prevent leakage of bleaching solution into the root tip. After that, you can use a sharp instrument (hook-like, Fig.4) to remove the temporary filling and cotton pellet (Fig.5). Then you squeeze bleaching gel (green) into the space as deep as possible (Fig.6). We also recommend that you use bleaching trays to do external bleaching at the same time. If you follow the instruction just mentioned and manufacture instruction to bleaching material well, you will be pleased with bleaching results in about one to two weeks (Fig.7). When you finish bleaching each day or every other day (if you have tooth sensitivity due to bleaching), you place a few of cotton pellet into the space to prevent food entrapment. Last you return to dental office to finish filling to seal the space (yellow, Fig.8). In fact the doctor uses the whitest material to further improve whitening. Two cases of external and internal bleaching have been presented in last lecture. Two more cases will be presented in next lecture to show that if you do not follow the instruction well, the result of whitening is not satisfactory. For example, if you do not remove the temporary filling (blue in Fig.3), you end up with external bleaching only. Talk to you next.
Xin Wei, DDS, PhD, MS 1st edition 02/01/2009, last revision 08/30/2009