Effects of presintering pigmentation on the physicochemical and optical properties of zirconia: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Personalized presintering pigmentation (PPSP) has been proposed to enhance the esthetics of monolithic zirconia. However, concerns remain regarding its impact on mechanical and optical properties. PURPOSE: The purpose of this study was to systematically review and meta-analyze the effects of PPSP on the physicochemical and optical properties of monolithic zirconia. MATERIAL AND METHODS: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided search of the PubMed, Scopus, and LILACS databases was conducted through December 2024. The protocol had been registered in the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY) (2024120027). Studies evaluating PPSP effects on zirconia physicochemical and optical properties were included. Random-effects meta-analyses were performed in RevMan 5.4 when at least 2 studies reported comparable outcomes. Risk of bias was assessed with the Risk of Bias tool for DEntal MATerials (RobDEMAT). Standardized mean differences were used to estimate pooled effects and the I² statistic to assess heterogeneity. RESULTS: Thirty-four studies were included. The descriptive review revealed that prolonged shading durations and acid colorants adversely affected most of the studied outcomes. The meta-analysis showed that when all techniques were combined, PPSP decreased zirconia's biaxial and flexural strength, except when the zirconia specimens had been industrially colored before PPSP (P<.001); the surface roughness (Ra and Rz) and the Vickers hardness translucency of industrially colored zirconia were also reduced after PPSP (P<.001). Although statistically significant reductions were observed, pooled flexural strength values remained above the International Organization for Standardization (ISO) 6872 standard minimum requirement for 3-unit fixed dental prostheses (800 MPa). Translucency parameters were within established acceptability thresholds. CONCLUSIONS: PPSP affects zirconia properties, but within limits that remain above the minimum flexural strength requirement for 3-unit fixed partial dentures and within established perceptibility and acceptability thresholds for translucency when manufacturer instructions are strictly followed.