There are two CEREC parameters that impact the occlusal firmness of our CEREC restorations. Understanding and then calibrating Occlusal Offset and Occlusal Contacts Strength will make all the difference in the quality of our occlusal results. Once mastered, it will be a major clinical theater stress reliever.
The Occlusal Offset controls the level of our occlusal table. This parameter does not show up on the virtual design screen, but will impact the occlusal milling. Before 4.0, I would calibrate this parameter with my Correlation mills (now called BioCopy), since this was the best way to calibrate Correlation occlusal quality. I discovered that -150 to -175 produced consistent Correlation occlusal right on strength. Fine tuning Occlusal Offset parameter is also impacted by reflective medium choice and application style for the Bluecam system. With Omnicam, I have shifted the Occlusal Offset to -200 with consistent results for BioCopy.
The second parameter that impacts the milled restoration occlusal firmness is Occlusal Contacts Strength. With the buccal scan and apposing arch scan, we are able to precisely manage both Biogeneric and BioCopy occlusion contact firmness and contact position placement. My Occlusal Contacts Strength number is -50 for both Bluecam and Omnicam.
Two other contributors to final occlusal firmness are occlusal contact placement/size and finishing style. The -50 Occlusal Contacts Strength produces a light blue color. I prefer to place my occlusal contacts on non-inclined surfaces on the working cusps, marginal ridges, and landing pad in the central fossa. The Occlusal virtual grinding located in the Tool feature will virtual grind occlusal firmness to the Occlusal Contacts Strength parameter. Following this tool virtual command, I then take the Form removal and smooth action and refine the occlusal contact size to 1 sq/mm and remove from inclined surfaces. It works like a charm and has provided consistent occlusal outcomes.
The last thing I want to do is remove the beautiful occlusal morphology because the occlusal table is high. This is stressful and takes away the incredible emotional rush that comes when our CEREC restorations drop in with perfect proximal contacts, margins closed and occlusion right on and the patient says, “Wow, that feels just right.”
As I instruct in my hands-on classes and my online cadstar.tv CEREC video tutorials, parameter metric recommendations is a place to start, and then fine tune relative to the user’s system and finishing styles.