Part 2: To Save or Extract a Tooth? That is the question

Our first blog discussed the structural, periodontal and esthetic requirements of saving or extracting a tooth. Appreciating the concepts of “Biological Width” (Figure 1) and  “Ferrule” (Figure 2), one can understand the relationships between the periodontal (gum) tissues and restorative dentistry. When a tooth can be saved by doing a crown, a periodontal procedure called “crown lengthening” will be discussed as a means to save your tooth in this blog.

Crown Lengthening Procedure

For the long term stability of your new crown, there must be an adequate amount of remaining tooth structure above the gums to properly retain the new crown. On average, this minimum amount of tooth structure above the gums is 4mm.1 When there is not enough remaining tooth structure above the gums a crown lengthening procedure will extend the height of the tooth above the gumline. Crown lengthening can also be performed to correct the esthetic appearance of your smile. Sometimes when you smile you may show excess gum tissue that makes your teeth appear short and uneven (Figure 3).  A periodontist will reduce the gum tissue and bone level in order to properly fabricate your crown. If a crown is fabricated and the principles of “Biological Width” and “Ferrule” are violated, the gums around the crown will become swollen, bleeding and painful. The body will try to combat the irritant in the gums in order to recreate the “protective seal” around the tooth.2

Crown lengthening is a very common surgical procedure, usually performed in less than one hour, and can be completed with local anesthetics or sedatives. Specialized surgical instruments will be used to recontour both the gum tissue and the underlying bone around the tooth for which your crown has been planned (Figure 4). Only the tissue in the immediate area surrounding the tooth will be treated. When adequate healing has been achieved, typically 6-8 weeks or longer depending on the location and tissue type, you will be instructed to return to your restorative dentist to finalize the dental crown treatment (Figure 4).

When the decision is made to retain your tooth, it may require a new crown and crown lengthening. Crown lengthening is a surgical procedure completed by a specialist. The doctors at PDG are specialists who routinely manage these types of cases and partner with dentists in the community to achieve a long term functional & esthetic result. In our next article, we will show a clinical case describing where a tooth cannot be saved. Your partner in dental health, Dr. Tassos Sfondouris.

References

  1. Shillingberg, Herbert et.al. Fundamentals of Fixed Prosthodontics. 4th Edition 2012. Quintessence Publishing Co,Inc.
  2. Padbury Jr A, Eber R, Wang H-L. Interactions between the gingiva and the margin of restorations. J ClinPeriodontol 2003; 30: 379–385

 

Figure 1: “Biological Width” and it describes a peripheral gum “seal” around our teeth that measures on average 2mm.
(Image from Spear Education)

 

Figure 2: To save or extract a tooth, we need 4mm of tooth structure above the gums. 2.5mm from gum margin to the bone and 1.5mm ferrule. This can be achieved by crown lengthening via bone removal, however it would be unacceptable esthetically. (Image from Spear Education)

 

Figure 3: The patient’s existing veneers were defective and unpleasing. Some of this was due to her short crowns. The plan was to perform crown lengthening surgery followed by ceramic crowns to improve the tooth proportions and ultimately the appearance of her new smile. (actual patient of practice)

 

Figure 4: After crown lengthening and ceramic crowns. (actual patient of practice)

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