What is Crown Lengthening?
Crown Lengthening. One of the most important, yet difficult to explain procedures in dentistry. Think of it like a banana. Say you peel a banana half way and discover a brown mushy spot mid banana extending down below the peel. In order to remove the brown spot, you must first peel back to peel to expose it. In this analogy, the banana is the tooth, the peel is bone, and the brown spot is decay. If you’ve got decay that extends below the gum line to (or below) bone level, then you must first remove bone (“pull back the banana peel”) to expose the lesion. This allows a more isolated, clean field. The dentist, then, can cleanly place a filling, crown, or other type of restoration without the obstruction of bone, bleeding, tissue, etc. The dentist (me) is “lengthening” the “crown” of the tooth by subtracting bone. I’m not REALLY lengthening the crown, but increasing the exposed part of the crown by removing the surrounding bony support.
Secondly, bone does not like to be close to a crown or a filling. Technically, there is a term “biological width.” This describes the safe distance of 2-3 mm between bone and the restoration (crown or filling). If bone is too close, the tissue gets red and bleeds. The area can become inflamed and hurt. An overall unhappy situation. Crown lengthening prevents this. Think of it like a bad wound. You must expose and clean the wound and area around it before covering it up with a band aid (or in this case… a crown!!).
Many dentists do not implement the crown lengthening procedure because:
A) They’re scared of it
B) They don’t know how to do it.
C) They don’t want the hassle/ loss of revenue/ logistic pain of sending the case to a specialist.
D) They don’t even know the crown lengthening procedure exists.
If crown lengthening is ignored in a case that requires it, the patient is destined to a lifetime of a bleedy, annoying crown. This will ultimately be blamed on a “cracked root” or something unrelated. I have actually seen some of these cases, sadly, be extracted.
Crown lengthening is a MINOR surgical procedure. It is no worse than a simple extraction or deep cleaning. I make a small incision next to the tooth, reduce a small area of bone with a round diamond bur and place suture. Very Simple. Then, after 2 weeks of healing, the crown or filling may be done.
The crown lengthening procedure takes about 30 minutes and will save a LIFETIME of tooth problems. Furthermore, the “restoration” (crown or filling) is a cleaner, quicker, and easy appointment for both the dentist and the patient. Yes, crown lengthening is an extra procedure (time, expense, etc.), but saves you BIG TIME in the long term.
Now that you understand the basic principal of Crown Lengthening, it becomes clear how this procedure can be used in cosmetic dentistry. The gums (or gingiva) is the “frame” of the tooth. It outlines the teeth and the smile. It can make the teeth look short, long, wide, thin, asymmetrical, or symmetrical.
Everyone wants their smile to look a certain way. Since the gums always sit a specific distance from bone, then (similar to the “biological width” concept) the bone position will dictate tissue position. The term “Cosmetic Gum Contouring” (Described elsewhere in this website) refers to the manipulation of gum tissue (alone) into a more esthetic position. BUT, if the bone position doesn’t allow the tissue to be moved past a certain point, then Crown Lengthening must be implemented. Does this make sense? You can’t move the tissue up to make a more esthetic smile if you’re going to be exposing bone. Believe me, you’re not going to like the way your smile looks with bone exposed!!!!! ; ) And Ouch!!
Therefore, the dentist must determine (usually by a technique called “sounding” where the bone is in relation to current tissue position and in relation to the target tissue position. With “Sounding”, I take a periodontal probe (a small pin shaped ruler on a handle) and push it down to the the level of bone. The ruler-like markings on the probe then tells me everything I need to know.
If bone does not interfere with my target tissue position, then I can do Cosmetic Gum Contouring (please see “Cosmetic Gum Contouring” section of website) WITHOUT having to do Crown Lengthening. Are all these crazy terms starting to make sense now??? Ok. Take a breath!
Below are some before and after photos of cases where Crown Lengthening was needed to move the tissue into a more esthetically appealing position. As you can see, some of these movements were significant. Therefore, such a dramatic tissue change could only happen in conjunction with the movement of bone.