CD0412

I CE article _ mastering occlusal function Fig. 24_The upper and lower models were articulated and the Biogeneric proposal was calculated. Fig. 25_The Biogeneric proposal was compared with the preoperative amalgam surface and adjustments were made. stabilized with composite. Over the course of many months,thecompositewasadjustedandmonitored for chewing efficiency and comfort (Fig. 22). After many occlusion checks in the office, it was time for the definitive restorations. Having all of the patterns of occlusion agreeable to the patient, the three-dimensional shapes just needed to be reproduced into ceramic. Biogeneric Copy was the method of choice. Anesthesia was given, and the lower quadrants were scanned in prior to removing the composite and amalgam. Conservative preparations were completed and the prepared quadrant was scanned into the software. Usingthepre-operativeshapeasaguidelineforthe final restoration, CEREC was able to reproduce the shapedevelopedintocompositeovermanymonths. The crowns were milled and inserted with no oc- clusaladjustment.Thepatientwashappythatthere wasnodifferencebetweentheestablishedcompos- iteshapesandthefinalizedceramicshapes(Fig.23). Themajoradvantagetothistechniqueisthatituses the ultimate articulator: the patient himself. _Using something new with something old There are two exceptional methods used in the CEREC Software 4.0 program to establish anato- mical design and occlusion: 1. Biogeneric Individual: a mathematical calcula- tion with buccal bite articulation 2. Biogeneric Copy: the reproduction of current anatomy. Thebuccalbitearticulationsetsthedigitalteethin one static occluding position and does not show lat- eral or protrusive interferences. A CR-CO movement is also not capable in this static position. This should be considered a snapshot of the patient’s occlusion, andthedoctorneedstobeveryawareofpotentialin- terferences outside the CO position. This is not diffi- cult to do because adjacent tooth incline planes can be compared, as well as cusp tip positions, for exam- ple. Withthearticulationofupperandlowermodels with the buccal bite, one can see the true intermaxil- lary space and build the design appropriately. How- ever, there are no motion paths within the CEREC program,andthiswillprobablybeadesirablefeature in the future. The pre-operative surface is the best indicator to the motion paths of the jaws currently. The Biogeneric Copy method as illustrated earlier will show motion paths of the mandible through years of service. However it has a limitation as well: a previously placed restoration may not have com- pletethree-dimensionalheightforocclusioninsome areas. In other words, it may not have function in all areas that it possibly could because the restoration was made in infraocclusion in some areas. For in- stance, a large amalgam may not have a marginal ridgethatisinocclusionbecausetheoperatordidnot makeithighenoughdirectlyinthemouthyearsago. Therefore, the new Biogeneric Copy milled restora- tion copied from this amalgam would be limited as well at the same amalgam marginal ridge. Although each method has a specific limitation, they can now be utilized together in the new CEREC Software 4.0. Therefore, the best of both methods can be used to determine the occlusion points and avoidinterferenceswithjawmotionpaths.TheBio- generic mathematical calculation is used to make the best anatomy and place the design in harmony with the maximum intercuspation position. Then, theBiogenericCopymodelcanbeutilizedtoanalyze 12 I cosmeticdentistry 4_2012 Fig. 24 Fig. 25