Introduction:
Bonding is considered the gold standard for the luting of all-ceramic crowns, as it provides strong micromechanical and chemical adhesion between the tooth and the restoration. This approach enhances retention, improves marginal adaptation, reduces microleakage, and supports optimal esthetics. However, bonding protocols must be tailored to the ceramic material used. Glass-ceramics, such as lithium disilicate, can be etched with hydrofluoric acid and silanized, achieving reliable bond strength. In contrast, zirconia requires alternative protocols, including the APC concept (air abrasion, phosphate monomer-containing primer, and composite resin cement), to optimize adhesion.

Methods:
Two clinical cases treated at the fixed prosthetic department of the dental clinic of Monastir, Tunisia, were selected for comparison. In the first case, a maxillary anterior tooth was restored with a lithium disilicate glass-ceramic crown (E-max) using conventional adhesive bonding with hydrofluoric acid etching and silane application, followed by resin cementation. In the second case, a zirconia anterior crown was placed following the APC concept.

Results:
Both treatment protocols demonstrated excellent clinical outcomes, including precise marginal fit, stable retention, and high esthetic integration. Postoperative follow-up revealed healthy periodontal tissues and patient satisfaction with the final appearance.

Conclusions:
Material-specific adhesive protocols are crucial for the long-term success of all-ceramic restorations. Hydrofluoric acid etching and silanization remain the gold standard for glass-ceramics, while the APC concept provides a reliable strategy for zirconia bonding. Understanding and applying these protocols enhances the functional performance and esthetic longevity of anterior ceramic crowns.