The waxed models were duplicated and poured again ( Figure 2D,E).Īt the next appointment, mock-up restorations were fabricated intraorally for esthetic and VDO evaluation. Then the technician completed the waxing of the canines, lower incisal edges, and lower third molars ( Figure 2B,C). Untouched canines and rearmost molars were strategic for the correlation between the waxed models and the preparations.
This step provided technical accuracy for intraoral repositioning of silicone guides for mock-up fabrication and provisional restorations and primarily enabled the use of the biogeneric copy in the software (CEREC inLab v4.0.2, Sirona Dental Systems GmbH, Bensheim, Germany) to generate the definitive restorations.
Both waxed models were then duplicated (Elite Double 32 Fast, Zhermack, Badia Polesine, Italy) and poured with scannable stone (Snow Rock 3D Scan, Dk Mungyo Corp, Hanrim-myun Gimhae-si, Gyeongsangnam-do, South Korea) ( Figure 2A). First, all teeth planned to be restored (maxillary arch: anteriors and premolars mandibular arch: second premolars, first and second molars) were additively waxed, except for the canines. 16 A complete mouth additive waxing was ordered (GEO Classic Mint-Opaque Wax, Renfert GmbH, Hilzingen, Germany) and carried out in two steps by the dental technician. The vertical dimension of occlusion (VDO) was arbitrarily augmented by 1 mm at the incisal to allow space for the restoration on the palatal aspect of the maxillary anterior teeth and to minimize the amount of preparation required for the ultrathin occlusal veneers. Centric relation (CR) was initially considered however, MIP position was utilized instead because the patient already had a retrognathic profile, which would be aggravated if CR was chosen. The bite was recorded at maximum intercuspal position (MIP), and casts were mounted on a semiadjustable articulator. 17, 18 Diagnostic casts (Pearl White GC Fujirock EP, GC America, Alsip, IL, USA) were obtained from complete arch polyvinyl siloxane impressions (Virtual, Ivoclar Vivadent). The restorative treatment was set in two stages: ultrathin CAD-CAM ceramic occlusal veneers on selected posterior teeth and bilaminar veneers (direct composite resin on palatal and ceramic on labial) on maxillary anterior teeth. 3 When experienced by young individuals, the tissue loss in moderate and severe cases of dental biocorrosion becomes problematic, resulting in significant biological (sensitivity and pulpal damage), esthetic, and functional consequences in addition to the complications due to the occlusal changes (with or without loss of the vertical dimension). 2 Modern lifestyles have led many to poor eating habits and dysfunctional behaviors that could explain the increase in prevalence of erosive lesions as well as their severity. Therefore, biocorrosion comprises endogenous and exogenous acidic and proteolytic chemical degradation of enamel and dentin as well the electrochemical piezoelectric action of the collagen in the dentin.
Likewise, the term “biocorrosion” differs from “corrosion” because the prefix “bio-” designates chemical, biochemical, and electrochemical actions on enamel and dentin. By definition, the term “erosion” is a physical mechanism, making the term “corrosion” more appropriate for dental tissues. However, the enamel thickness is reduced by dental biocorrosion. The dental enamel shell is designed to withstand a lifetime, 1 as witnessed in many patients in their 80s and 90s who can still enjoy their teeth despite obvious signs of wear and cracking.