A 66-year-old man reported to the appointment with complaints related to impaired aesthetics. The intraoral clinical examination revealed the presence of worn maxillary and mandibular dentition, with dentinal craters and sharp edges on the enamel of remaining teeth (Figures 1-4).
Upon extraoral examination, the patient showed bilateral hypertrophy of the masticatory muscles. The radiographic examination revealed the absence of tooth number 20. Teeth number 9 and 19 had previous endodontic treatment and direct composite restorations (Figure 5). Both posterior maxillary and mandibular dentition displayed worn occlusal/incisal surfaces. No anterior or canine guidance for eccentric jaw movements was present. The magnitude of occlusal vertical dimension loss was achieved using the interocclusal rest space with the jaw in rest position that was found to be around 6 mm, greater than the normal value (2 to 4 mm).
The treatment options were explained and a conservative treatment modality was adopted, which included the preparation of maxillary and mandibular canines and first molars for monolithic zirconia crowns in order to obtain four-point occlusal stability on the increased vertical dimension, that would allow to rehabilitate the anterior teeth with porcelain veneers and the remaining posterior teeth with ceramic overlays with facial coverage. In order to improve aesthetics, these monolithic zirconia crowns were veneered with porcelain in nonfunctional facial areas. A dental implant was proposed on the region of tooth number 20, but the patient decided to place a fixed bridge.
An informed consent was obtained from the patient. After facial and smile analysis, the photographic sequences were obtained and intraoral impressions were taken with irreversible hydrocolloid (Orthoprint, Zhermack). The digital planning using a digital smile design was complemented with a diagnostic wax-up that was produced on study casts and a direct mock-up with bis-acrylic composite (Protemp Plus, 3M ESPE).
All changes needed were done on the mock-up, and a silicone guide was obtained. Following this, the canines and first molars of both arches were prepared for full crowns. A medium grit diamond bur with rounded edge was used to ensure a minimum axial wall thickness for zirconia of about 1.0 mm to 1.5 mm. At gingival margin, a continuous circumferential chamfer with at least 0.5 mm reduction was made. A minimum of 1.5 to 2 mm incisal/occlusal reduction was ensured, approximately. The vertical and horizontal preparations were performed in order to obtain an angle of approximately 6 to 10 degrees between them. All edges and angles were rounded.
The anterior maxillary and mandibular teeth were minimally prepared for veneers, ensuring a minimum restoration thickness on the cervical and labial area of about 0.5 mm and 0.7 mm on the incisal edge. All other teeth were only softened from the sharp edges of the enamel.
Then, the retraction cords were applied (double retraction cord technique, #000 and #0 Ultrapak, Ultradent) and elastomeric single step impressions were made with putty and low consistency polyvinylsiloxane impression materials (Affinis, Coltene) to obtain the definitive casts. Maxillomandibular records (facebow) with the increased occlusal vertical dimension were obtained, and the master casts were mounted on a semiadjustable articulator. After tooth preparations, provisionals on the anterior teeth and first molars were placed and cemented with noneugenol temporary dental cement (TempBond NE, Kerr).
Digital technologies were then included in the workflow with the laboratory scanning of the master casts and CAD/CAM manufacturing software, along with computer-controlled machinery (Zirkonzahn).
The casts and the wax-up were scanned into the computer-aided design software in order to produce the monolithic zirconia crowns for the canines and first molar crowns. Facial cutbacks for feldspathic ceramic were made digitally in order to improve aesthetics on these crowns. These crowns were designed in such a way so that the incisal edges of the canines were included and the veneering porcelain was applied only onto nonfunctional labial/buccal areas. The monolithic zirconia frameworks were milled using CAD/CAM software according to the manufacturer's specifications (Prettau Zirkon, Zirkonzahn).
Following framework proof and occlusal adjustments of canines and first molar upper and lower crowns, ceramic was applied on the facial surfaces of the monolithic zirconia frameworks (IPS e.max Ceram, Ivoclar Vivadent) and the feldspathic veneers for the anterior maxillary and mandibular teeth were produced (IPS e.max Press, Ivoclar Vivadent).
The canine and first molar monolithic zirconia crowns were cemented according to the manufacturer's instructions. The crowns were pretreated with aluminum oxide sandblasting (110 mum; 3.5 bar), steam blasted, and dried with compressed air. After the application of the bonder, the excesses were removed by compressed air and the crowns were allowed to dry for 60 seconds. The dual-cured resin cement (RelyX Unicem, 3M ESPE) was applied, and the crowns were finally inserted. After an initial polymerization of 2 seconds of light cure, all the excesses were removed and a glycerin gel was applied before the final polymerization of 120 seconds.
The anterior upper and lower porcelain veneers were cemented with resin cement (RelyX Veneer Cement, 3M ESPE).
Immediately after cementation (Figures 6 and 7), a digital scan of remaining teeth of booth arches and a bite registration was obtained with an intraoral scanner (Trios, 3Shape) (Figure 8). Posterior facial and occlusal lithium disilicate glass-ceramic restorations were that obtained via CAD/CAM (IPS e.max CAD for Cerec and inLab, Ivoclar Vivadent) (Figure 9) and cemented on the same day with composite (Figure 10).
Minor occlusal adjustments were made intraorally and polished with polishing burs. Canine guidance and anterior guidance were also verified for eccentric jaw movements with posterior disclusion. A panoramic radiograph was obtained after cementation (Figures 11-13), and oral hygiene instructions were given to the patient such as an acrylic occlusal mouthguard for nocturnal use. The patient expressed his complete satisfaction with the aesthetics and function value of the final restorations. After 4 years, no complications were found with respect to fracture or cracking of any restoration (Figures 14 and 15).