Verification index

A verification indexes sole purpose is to ensure the analogs in the master model are positioned in relation to each other exactly the same way as the implants to each other in the patients mouth. Since implants do not have a periodontal ligament and therefore do not move like natural teeth the degree of precision needs to be exceptional. A CAD CAM titanium bar can not be retrofitted in case of ill fit because it is impossible to laser weld a titanium bar after it has been sectioned. To avoid a costly remake it is mandatory to make and try in the patients mouth a verification index. Every CAD CAM bar manufacturer requires a confirmed verification index be supplied with every case submitted for milling.

Luted temp cylinders

To make a verification index it is best to use non indexed metal temp cylinders or non indexing impression copings if available for the pertinent implant brand at hand. Remove the soft tissue mulange from the working model and secure each cylinder with a corresponding screw to the analogs in the working model. Connect the cylinders with Pattern Resin LS (GC)  or Triad® (Dentsply Truebyte) light cure material to form a bar. Once the connector material is cured remove the bar from the model. Replace the soft tissue mulange back on to the working model and reseat the index. Adjust the index until it seats without impinging on the soft tissue. Remove the index and the soft tissue mulange from the working model and reposition the index back on the model. Hand tighten only one screw and attest all cylinders seat properly.

Index try in

At the time of try in fasten the index with only one screw and observe if any other temp cylinders do not seat completely on the implants. If the abutment implant interface is too far below the tissue and seating can not be observed visually take an x-ray to ascertain proper seating. Should the index not seat passively section the index and fasten each temp cylinder with a screw to the corresponding implant. Lute the index in the patients mouth back together with GC pattern resin or light cure material. Send the index and all model work back to the laboratory to reset the analogs in the existing working model.

Repositioned analogs

Upon return of the seating index from the try in appointment, inspect the index if it has been sectioned and reluted by the dentist. In case the index was reluted the offending analog needs to be removed from the working model. Grind out the analog by carefully removing the stone around the analog to be repositioned. Care should be taken not to damage the abutment analog interface of the analog. Once the analog is removed from the stone model screw the now free analog on to the verification index and screw the index back on to the remaining analogs of the working model. Ensure the repositioned analog does not touch or bind the stone around the hole in the working model. Use GC pattern resin or light cure material to reattach the analog in the new position in to the model. Now the model is ready to be scanned for any CAD CAM bar restoration.