By Armen Mirzayan, DDS
The author had the opportunity to use Sirona’s new CEREC® Omnicam (Sirona Dental Systems, LLC,www.sirona.com) for a few months while it was in its initial testing stages. First introduced in August 2012, this new camera has some incredible new features. Designed for access, the Omnicam is small enough to allow for the best intraoral access in even the tightest spaces. It is also very lightweight, making intraoral access easy. This is critical in capturing impressions within tight spaces such as second and third molar areas.
One compelling feature of the CEREC Omnicam is that it is truly powder-free, scanning tooth structure without the need for an opaquing medium. This addresses the intimidation factor for the potential new user who may have found this task difficult to overcome. Essentially, practitioners need not alter any traditional skill sets to
operate the CEREC Omnicam; they need only to prepare the tooth adequately, achieve hemostasis, and place the Omnicam over the working field.
The most progressive feature of the new CEREC Omnicam is its unique ColorStream capture, which makes it possible to distinguish soft tissue from hard tissue based on inherent color characteristics, and more importantly, to discern restorations from enamel and dentin. Clinicians can also identify and differentiate amalgam restorations, soft tissue, dentin, enamel, and green retraction cord.
A patient presented with a fractured all-ceramic crown (Figure 1). While it is well known that ceramic restorations require bulk for strength, it was evident that this crown did not satisfy that requirement. The patient was informed that a new crown was warranted, and gave consent for the restorative process to begin.
After the patient was anesthetized, the preparation was made, providing enough clearance for a lithium-disilicate crown. When hemostasis was achieved (Figure 2) the CEREC SW 4.0 was then launched; it selected the material, tooth number, and design type (Figure 3).
Initially, the upper dentition was captured with Color Streaming. Figure 4 shows a snapshot of the landscape and a layout of the software. On the left, there is a live view, so the doctor can perfectly visualize the area, and on the right, the 3-D model preview is rendered (Figure 5).
The clinician moved the camera over the area until a solid model was formed. After capturing the opposing maxillary quadrant, the buccal bite was addressed (Figure 6). The patient bit down into the maximum intercuspation and the images were taken from the buccal area, as opposed to the mandibular and maxillary arches. The models were then articulated together with the buccal bite model.
Once the models were related to each other, the practitioner trimmed the master model into dies and placed the margin. The color contrast of the green retraction cord and white tooth structure allowed for easy identification of the margins (Figure 7).
Once the margins were verified, the CEREC SW 4.0 proposed a restoration (Figure 8 and Figure 9), using the patented biogeneric algorithm, where the software derived the morphology of the proposal from the adjacent teeth, made positive contact with the adjacent teeth, and placed the restoration into occlusion with the opposing arch.
Fine adjustments were managed by the “scale” (Figure 10 through Figure 12) and the “smooth and remove” tools. The whole design process took only a few minutes, since the CEREC SW 4.0 did most of the work for the dentist.
Once the contacts were checked and the design was finished (Figure 13and Figure 14), the restoration was milled in just 10 minutes (Figure 15).
A lithium-disilicate restoration was then placed in the patient’s mouth to verify accuracy and fit, and crystallized in an oven for 13 minutes. The restoration turned a natural tooth color, and was placed into the patient’s mouth with a fourth-generation bonding agent and resin cement (Figure 16 and Figure 17).
The whole process from anesthesia to delivery of the restoration took a mere 80 minutes. The doctor’s total work time consisted of preparing the tooth and delivering the restoration. Properly trained staff can attend to the design and processing steps so that the practitioner can attend to more productive matters.
Dr. Mirzayan has been a CEREC user since 2001, and a beta tester for Sirona since 2002. He is the co-founder of CERECDoctors.com, an online educational website.
About the Author
Armen Mirzayan, DDS- Private Practice, Los Angeles, California
October 2012, Volume 8, Issue 10
Published by AEGIS Communications