Purpose: The purpose was to investigate the effect of simulated intra-oral temperature and humidity variations on dentin bonding performance of resin luting agents.

Methods: A self-cure resin luting agent (Super-Bond C&B, SB) and dual cure type resin luting agents (Panavia V5, PV; RelyX Ultimate, RU; Estecem II, E2) were used. The PV, RU, and E2 groups were divided into two sub-groups; light cured (LC) and self-cured (CC). Specimen preparation was performed at room temperature (LAB), supragingival finish line (SUP), and subgingival finish line (SUB) simulation occurred in a thermostatic device (31 ± 2℃/93 ± 3%). The SUB specimens were stored in water 10 s after bonding. Shear bond strength (SBS) values were measured and analyzed using Dunn's test with Bonferroni correction (P = 0.05).

Results: The bonding performance of SB was stable under all the environmental conditions. In contrast, the SBSs of PV, RU, and E2 significantly decreased in SUP and SUB (P < 0.05). The SBSs of PV, RU, and E2 were reduced in CC (except for PV/LAB).

Conclusion: The bonding performance under the three environmental conditions were resin luting agent dependent. SB provided the highest SBS regardless of the bonding environments. Light irradiation strongly influenced the bonding performance of the dual cure resin luting agents.

Purpose: This study aimed to compare the effects of two different color shades (A2, A3) and thicknesses of translucent zirconia materials on translucency and to compare the masking ability of these materials on different colored abutment teeth (dentin, resin, and metal).

Methods: Highly transparent zirconia (ZR Lucent Supra, Shofu) was used to fabricate plate specimens with five different thicknesses (0.5, 1.0, 1.5, 2.0, and 2.5 mm), and monolithic zirconia crowns of the maxillary left central incisor. Three different colored abutment teeth (dentin, resin, and gold-colored) were fabricated. The translucency parameter (TP) and color difference (ΔE₀₀) were calculated from the L*, a*, and b* obtained by measurement. The color difference (ΔE₀₀) between crowns of different abutment tooth colors and reference color specimens was calculated.

Results: The TP values decreased significantly as the thickness of the specimens increased. The ΔE₀₀ was significantly different for gold-colored teeth compared to dentin- and resin-colored teeth (P < 0.05).

Conclusion: The color difference between the reference values was large for highly translucent shade-gradient monolithic zirconia crowns, regardless of the shade, when the abutment-tooth color was gold. The study findings indicate that to achieve a highly esthetic crown, the color of the abutment tooth and the thickness of the crown should be considered.

A simple processing technique for a denture marking plate is reported. An outline of the rectangular plate was designed with a three-dimensional (3D) software. The alphanumeric size was set at approximately 2-mm in height. The current case printed telephone code number, abbreviation of university, and prefectural code, with 0.75-mm in depth. The alphanumeric groove was filled with white colored opaque resin. The plate was inserted into the denture base with an acrylic repair resin. The numbers and letters were clearly visible through the acrylic resin material. This method is applicable to varying sizes of marking plates placed on partial dentures.