Partials | Chromeworks Inc.

Rest Prepping: Tried & True or Tested

Please consider these Rest Prepping techniques!

Prepping teeth is a study that is beyond the scope of this site. There are however, a few things we can discuss to help keep us all out of trouble and produce an exceptional result for the patient.

I-Bars:

A mesial rest is always a great option for either upper or lower bicuspids. Consider that rarely is the mesial-occlusal areas of #21 and #28 ever in occlusion. Prepping may not be necessary here.

Akers:

A distal rest is customary with a retentive buccal and lingual reciprocal arm. Consider a mesial rest as in the RPA clasp. Please check the opposing teeth for clearance.

Cuspids:

Upper cuspids require an evaluation of the opposing clearance. We find a mesial rest with slight reduction gingivally for room usually meets all the requirements and allows for a variety of clasp designs including aesthetic clasps. Lower cuspids are much easier as occlusal problems typically don't exist. We like the simplicity of a chevron rest on these teeth.

Double Akers (crib clasp):

These are all too often a problem. We need a minimum of 1.5mm clearance for these as in the illustration. We often receive "dots" in the center of the occlusion leaving little, if any, room for the clasp assembly to clear the opposing. Please cut through buccal-lingually as shown.

An Important Note on reducing opposing tooth:

We spend an extraordinary amount of time to make sure our partial frames are not bulky and are free of occlusal interference. We make sure the rest areas are as thin as the alloy will allow. When shallow prepping leaves us with insufficient room to accomplish this we are forced to remove from the opposing. We always mark this in red on your model in the hopes the natural dentition will be reduced as indicated. Grinding on the frame to free up the occlusion will void the warranty and significantly impair the frame or reduce its effective life. We understand that certain teeth and patients can be difficult and have solutions for each case. Crowns and fixed bridges can be the most difficult to adjust. Please call before final impressions so we can discuss the alternatives. Thanks.

We like good communication! Your objective is our objective. Is it (In order of importance)...

Aesthetics? Seems to be the trend these days, and who can blame them?
Retention?
Strong bite?
Stress relief?
Weak teeth?

We can help. You might be interested in...

Resin Clasps

With the right shade, these are an aesthetic and reliable alternative. Also resin clasping is turning out to be quite a stress relieving as well.

Diverse designs can radically increase or minimize retention when needed.

Hinges

They might cost more but they are a great way, when properly fitted to healthy tissue (ie. relined appropriately, to save weak teeth. We don't recommend hinges on uppers but we still make them occasionally when asked.

Gold Clasping

Gold clasping is one of the finest ways to retain a partial! Either with a full gold frame or a blend of chrome-colbalt and gold. With the addition of our laser, we can now do remarkable fusions of gold and chrome. We also have round gold and pgp wire for very light retention applications.

Bite Openers:

Consider resin before metal.

Appliance Fractures:

Breaking Dentures? Look to alignment of teeth over ridge.
Dentures breaking down the midline?
Teeth or saddles breaking off?

Allergies or other reactions to the appliance

Patient having a reaction to the partial? Over the past 20 years we have experienced very few allergic reactions to our alloys -Nobilstar, V2000, V2000+. Based on our experience, please consider these conditions:

Has the partial been processed using a "heat cure" system or has it been "cold cured"? too many suspected metal allergies turn out to be under-cured acrylic. Try re-curing the denture overnight under pressure and heat.
Has the partial been repaired using a nickel based "brazing" type weld material? A laser will eliminate the need for nickel-based soldering alloys.
Consider doing a patch test using a small square of alloy to determine if the problem is an alloy or acrylic reaction.
Consider gold (JLCB) as an alternative alloy. Most patients intolerant of chrome-cobalt will do fine with gold.