Effect of Provisional Cements on Shear Bond Strength of Porcelain Laminate Veneers

Abstract

Objectives: The purpose of this study was to evaluate the effect of three provisional cements and two cleaning techniques on the final bond strength of porcelain laminate veneers. Methods: The occlusal third of the crowns of forty molar teeth were sectioned and embedded in autopolymerizing acrylic resin. Dentin surfaces were polished and specimens were randomly divided into four groups (n=10). Provisional restorations were fabricated and two provisional restorations were cemented onto each tooth. Restorations were fixed with one of three different provisional cements: eugenol-free provisional cement (Cavex), calcium hydroxide (Dycal), and light-cured provisional cement (Tempond Clear). Provisional restorations were removed with either a dental explorer and air-water spray, or a cleaning bur (Opticlean). In the control group, provisional restorations were not used on the surfaces of specimens. IPS Empress 2 ceramic discs were luted with a dual-cured resin cement (Panavia F). Shear bond strength was measured using a universal testing machine. Data were statistically analyzed by ANOVA, Tukey’s HSD and Dunnett tests. Surfaces were examined by scanning electronic microscopy. Results: Significant differences were found between the control group and both the light-cured provisional cement groups and the eugenol-free provisional cement-cleaning bur group (P<.05). Groups that had received light-cured provisional cement showed the lowest bond strength values. Conclusions: Selection of the provisional cement is an important factor in the ultimate bond strength of the final restoration. Calcium hydroxide provisional cement and cleaning with a dental explorer are advisable. (Eur J Dent 2011;5:373-379)

Effect of Intraoral Mechanical Cleaning Techniques on Bond Strength of Cast Crowns to Metal Cores

“…Intraoral clinical surface cleaning methods can include mechanical cleansing or the use of chemical agents. Commonly used mechanical cleansing methods reported in the literature include the use of dental explorer/excavator or pumice with rotary brush …”

“…An interim prosthesis requires the use of provisional cement. The use of provisional cements has been reported to adversely affect the retention outcome of indirect restorations when luted with resin cements . This is due to the surface residue contamination and resultant change in surface free energy associated with provisional cements, adversely decreasing resin cement shear bond strength .…”

“…Studies have evaluated the effect of surface residual contaminants from provisional cements on the shear bond strength of definitive indirect restorations . Abutment preparation surface and intaglio surface contamination of a definitive restoration could also develop from remnants of restorative fit checking medium . These residues are considered common contaminants and should be completely eliminated prior to definitive cementation …”

“…A common clinical scenario for endodontically treated teeth is the presence of a metal core. Elimination of provisional cement contaminants from metal cores prior to definitive cementation of indirect crown restorations is crucial to ensure a good outcome . However, not all extraoral cleaning methods are suitable for intraoral use.…”

Essential Considerations for the Cementation of Facets and Ceramic Laminates

“…Ceramic veneers not only restore the smile, but also allow the biomimetic recovery of the dental crowns. In cases requiring correction or change in tooth shape or position, changes in morphology, ceramic veneers exhibit promising aesthetic results when clinical procedures are carefully performed 9 .…”