Denture Teeth For Flat Gums

                      Zero Degree Teeth & Flat Plane Occlusion                                                       By: F.Spiva Jr. CDT MDT CD
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                                                   <Thedenturepro@AOL.Com>

 

     “Zero Degree Denture Teeth”
     When you look into your own or someone else’s mouth and observe the chewing
surface of the teeth, you will note that the chewing surface, from side to side, forms a “V”(vee). The tooth edge next to the cheek slopes downward towards the center of the tooth, and then slopes back up to the tooth edge on the tongue side. Those edges and slopes are  what we call “Cusp’s”. Where the slopes meet in the center of the tooth we call the (central  groove) . The “central groove” divides a molar (back tooth) from side to side meaning the cheek side and tongue side.

    The angle of the slope from the top of the cusp down to the “central groove”, in
manufactured denture teeth, ranges from a 10 degree slope to as steep as a 33 degree slope.The “Zero Degree” denture tooth has no degree of slope. The chewing surface is “flat”, but the surface has cutting grooves created in much the same manner as if you viewed the old teachers paddle. The paddle had holes drilled in it and the tooth has depressed areas as though a tiny ice cream scoop removed part of the flat surface leaving circular pockets. The edges of those tiny pockets act as a cutting blade in the same manner as the edges of the holes in the teachers paddle. Applied with enough force against skin or a food material,those edges cut like a knife.......”Zero Degree Denture Teeth” are flat surfaced yet can cut like a knife with cutting circular grooves in the chewing surface.

 

     “Flat Plane Occlusion”
 Once again lets look into a mouth of natural teeth.  If you took a soft piece of wire
about the size of say a hair pin and placed one end on top of the last back tooth and pressed it against the chewing surfaces, say down through the central groove of the other teeth, moving forward to the front tooth we usually call the stomach tooth (1st. right or left, lower cuspid).  If you then remove the wire, you will see that it is not straight and level, but curved front to back like the floor runner on a rocking chair.

    If you take another piece of wire and place it on top of the cheek side edge or cusp of a molar tooth on the right side of the mouth, and then press it down against the tooth’s surface allowing the wire to extend across over the tongue and press it against the molar tooth on the left side of the mouth, when you take the wire out of the mouth you will note that it also is not straight and level but forms a curve.

    You now have two pieces of wire that proves that your teeth grow not on a level
plane but rather in two curves, one front to back of the jaw and the other side to side of the jaw.......Now, how is that important to the construction of dentures. First of all denture teeth are not buried in bone, they sit on top of the gums. You then have to see that natural teeth come together like a set of teeth on gears. A better example might be to place your hands together and slightly let you fingers interlock....that’s how natural teeth fit against one another.

     Now place you hands together and do not let your fingers lock, keep the fingers
tight.You can now rub your hands together in any direction you choose without
interference......That is, if you will, “Flat Plane Occlusion”.

     “Flat Plane Occlusion” as it relates to dentures means that the denture teeth are set “flat” and “level”. The two curves that we know exist in natural growing teeth are avoided.Technically those two curves are called “The Curve of Spee” and “The Curve of Wilson”. My experience over 40 plus years of creating dentures was that Zero Degree Denture Teeth set on a Flat Plane of Occlusion provided the patient with dentures that were more stable, better balanced and created less problems in chewing.

     Dentures created with denture teeth having deep degreed teeth and set in the curves of Spee and Wilson often times created interference in the chewing motions. The usual chewing action created by these types of dentures is Bite, Slide, Bump, Climb and Chew......The chewing action with Zero degree teeth on a Flat plane is Bite and Chew. My patient success over my years of practice is estimated at over 95%. I believe that using the Zero Degree Denture Teeth set on a Flat Plane of Occlusion is the major factor in that success.....Of course there are other techniques and I used them when I thought they would provide the best results. Feel free to respond on this site or contact The Denture Pro. at thedenturepro@aol.com for a personal response to any question you may have.