Clinical implications of the use of ceramic restorations in 36 months of observation

Introduction. Zirconium-based ceramic restorations have very good aesthetics, biocompatibility and mechanical strength. Despite many advantages, there are also disadvantages, which include: incidents of porcelain chipping, cracks or breaks in the structure of the ceramic fabrication and accelerated aging phenomenon of zirconium oxide, consisting in spontaneous transformation of crystalline phases and drastic reduction in strength parameters. Aim of the study. To perform clinical evaluation of zirconium-based ceramic restorations after 36 months of use. Materials and methods. Functional and aesthetic aspects of crowns and bridges were evaluated by means of the California Dental Association quality assessment system for fixed restorations and the measuring devices DIAGNOdent and Florida Probe. Statistical analysis was performed. Results. No instances of cracks or fractures of zirconium restorations were observed in the analysed period. Chipping of porcelain was noted in twelve restorations. According to the CDA criteria, 90% of restorations after 36 months of use had “acceptable” marginal integrity and aesthetics. There were no statistical differences between the level of demineralization on the surface under the crown’s edge or a similar surface on adjacent natural tooth, as well as between the depth of gingival pockets of abutments and control teeth. Conclusions. Zirconium oxide-based ceramic restorations during 36 months of use in most cases fulfilled functional and aesthetic requirements. Although porcelain chipping constitutes a major disadvantage, it does not necessarily have to lead to the restoration’s replacement. Abutment teeth with zirconium restorations as well as adjacent natural teeth are equally prone to caries and periodontal diseases.