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Dental Education Lecture: In Office Bleaching

There are two ways to treat severely discolored front teeth: bleaching and crown.  Bleaching is more conservative.  We save tooth structure.  It is also easier to maintain oral hygiene with your own natural teeth.  These days we often use all porcelain crowns to repair the front teeth.  Bleaching makes cosmetic crowns/veneers more beautiful, because discoloration can show through transparent cosmetic crowns.

It is our routine to let the patient do take-home external and internal bleaching first.  It is easy to do and less expensive.  If for any reason take-home bleaching is not very satisfactory, we will supplement with in office bleaching.  In last lecture, one patient is unable to remove the temporary filling.  At home internal bleaching is not done for a discolored tooth.  In office bleaching gives rise to excellent results.  Today we introduce a new case in which we need to supplement in office bleaching to treat two severely discolored teeth.

A 40 year-old lady seeks treatment because one of heavily discolored teeth (#9, Fig.1) is chipped.  Both teeth have root canal therapy done before.  A mismatched filling material is shown through the shell of #8 crown.  We decide to try take-home bleaching.  We remove old fillings and create spaces for internal bleaching.  She follows instruction very well.  Two or three weeks later, she return.  The tooth #9 is still pretty dark (Fig.2).  For unbiased comparison, we take photos with two shade guides (labeled as A2 and A4) by side before (Fig.3) and after (Fig.4) in office internal and external bleaching.  You may notice that in office bleaching whiten these two teeth further.

To do in office bleaching,  we need to place isolation dam (light blue in Fig.5) to protect nearby gums from being bleached and then place bleaching material (dark blue) on the tooth surface as well as inside part of the root canal space (not shown).  A special lighting (on the lower right corner of Fig.5) is used to facilitate whitening effect.  Bleaching dressing is changed several times for maximum results.

Fig.6 shows these two front teeth when white filling is finished.  As compared to Fig.4 taken before filling, it is apparent that white filling improves whitening a little more.  At least we lay a good foundation for cosmetic crowns, which will be discussed next.

The patient in Fig.7 and 8 does not want to do any bleaching after root canal therapy is done for #8.  For tooth labeling, see Fig.1.  White filling is re-done (compare Fig.7 and 8).  It appears that new white filling placed on a discolored tooth looks not so white, instead very dull.  He may need several crowns with masking technique.  We will discuss crowns/veneers to fix discoloration.  See you next time.

Xin Wei, DDS, PhD, MS 1st edition 02/01/2009, last revision 03/21/2010