Raising the Vertical Dimension of Occlusion
ArgenZ Anterior (ST) Monolithic Zirconia in a Full-Mouth Rehabilitation
When treating a patient for anterior guidance, the first step begins with investigating cuspid function. For proper occlusion, the incisal edge of the lower anterior teeth should come to a vertical stop in the middle third of the maxillary anterior teeth. Patients without proper incisal occlusion frequently develop problems regarding the vertical dimension of occlusion (VDO) or the vertical separation between the jaws when the teeth are in contact.
The patient, a Class II Division II patient, exhibited a deficiency in VDO with evidence of a bite collapse. The patient also exhibited a decreased lower one-third facial height. Most symptoms were seen intraorally. The cuspids were misaligned and occluding without overjet, resulting in continual bruxism that can be seen in the severe wear of his lower arch, especially on the incisors. The main objective of this case was to establish a proper occlusal scheme, by establishing proper centric relation along with adequate anterior guidance, and increasing the necessary VDO to improve facial height and provide a new and brighter smile with a full-mouth reconstruction (Figure 1 and Figure 2).
• Prevent potential TMJ issues and pain with proper occlusion.
• Give overjet to establish vertical overlap and stop incisal edge wear.
• Create harmonious Curve of Spee to correct appearance of worn anteriors.
• Improve buccal corridor.
• Establish simultaneous bilateral posterior contacts.
• Improve esthetics with a fuller, more natural smile.
The patient expressed a desire for all-ceramic restorations. However, due to the patient’s history of severe grinding, strength and esthetics were crucial for the long-term clinical success of the restorations. With a flexural strength of 765 MPa and super-translucency, monolithic ArgenZ Anterior was the ideal choice over lithium disilicate, which requires a more aggressive tooth reduction. Having used ArgenZ Anterior for 2 years now, we have found this zirconia to be the best all-ceramic alternative that offers predictability in its strength, much less tooth reduction, and the ability to mimic the appearance of natural teeth.
Casts were generated from full upper and lower impressions. A face-bow transfer was done using the Kois Dento-Facial Analyzer System (Panadent, panadent.com) to mount the upper cast. Then, both arches were mounted onto a semi-adjustable Panadent articulator (Figure 3).
Deprogrammers: Bite Jig and Open Bite Splint
An initial overbite of 5 mm was recorded regarding the starting incisal edge position relative to the lower incisal edge. Through extensive diagnostics, including phonetics and photos, a 2-mm inner occlusal opening was found necessary to raise the VDO. The incisal pin on the Panadent articulator was raised by 2 mm to simulate the new VDO. An opening bite jig (deprogrammer) was fabricated and transferred to the mounted models (Figure 4). A full-mouth open bite splint with the 2-mm inner occlusal increase was fabricated and worn by the patient for a total of 6 weeks to determine whether or not he could tolerate the new vertical opening. After ensuring the new open vertical dimension would be tolerable, diagnostic planning began.
A full-mouth diagnostic wax-up was created according to the new VDO and presented to the patient for approval. The wax-up was replicated into solid models for later use in the production of temporaries and final crowns. The full diagnostic wax-up became the blueprint for all phases during treatment (Figure 5).
Restoration Treatment Lower Arch
At the initial preparatory appointment, the lower arch was done first to achieve proper phonetics, as the 2 mm would primarily be dedicated toward raising the lower anterior teeth. The lower teeth were prepped in three stages: posterior left, posterior right, and anterior. After prepping each posterior quadrant, bite registrations were taken with the deprogrammer in place on the anterior teeth as a reference for the desired occlusal space. The anterior teeth were then prepped and bite registration was captured with the posterior bites in place to capture the proper vertical.
Temporary mock-ups were generated from the wax-up and used to create temporaries. 3Shape digital technology was utilized during the production process. The full-diagnostic wax-up was scanned to be later transposed on the prepped lower arch model. Crown designs were morphed from the diagnostic wax-up and connected to the prepped margin lines. The crowns were milled from ArgenZ Anterior (ST) Monolothic Zirconia and sintered according to parameters developed by Argen. Staining was done according to Zirkonzahn (zirkonzahn.com) staining guidelines with Newport Beach Smile Designs techniques (Figure 6 and Figure 7).
The entire lower arch was seated successfully. No adjustments were done on the final crowns, and only minor balancing adjustments were made on the upper teeth.
Two weeks later, the upper arch was prepped following the same protocol as the lowers. The nature of working in segments and replacing bite registration for any upper prepped teeth cannot be overstated as to maintain tripodization and minimize any inaccuracies in the vertical occlusal space. A temporary mock-up was again generated from the wax-up and used to fabricate temporaries.
Like for the lower arch, the final crowns for the upper arch were designed digitally and morphed from the full-mouth diagnostic wax-up with the prepped margin lines. Similar milling, sintering, and staining procedures from the lower arch were performed as well. The final crowns were seated and final adjustments were made (Figure 8 and Figure 9).
Clinical work was performed by Dr. Keith Cowhey in Seal Beach, California. The author also thanks Anthony Hua for his contributions.
About the Author
Disclaimer: The statements and opinions contained in the preceding material are not of the editors, publisher, or the Editorial Board of Inside Dental Technology.
Manufacturer Contact Information