Influence of CAD/CAM zirconia for implant-abutment manufacturing on gingival fibroblasts and oral keratinocytes.

OBJECTIVES: This study investigated the influence of three CAD/CAM zirconia ceramics for implant-abutment manufacturing on cell viability, migration ability, and cytotoxicity of human gingival fibroblasts (HGF) and oral keratinocytes (HOK) in vitro. MATERIALS AND METHODS: HGF and HOK were cultured on zirconia ceramic disks (VITA In-Ceram YZ, Ivoclar IPS e.max ZirCAD, Sirona inCoris ZI) and on control disks made of tissue culture polystyrene. Cell viability was analyzed by a MTT assay. Migration ability was detected by a scratch assay. A ToxiLight assay was used to analyze the influence of the tested zirconia ceramics on adenylate kinase (ADK) release and cytotoxicity. RESULTS: At MTT assay, HGF showed an increased cell viability compared to the control after 9 and 12 days for all ceramics (p each ≤0.0002) while HOK demonstrated a decreased cell viability after 9 and 12 days for all ceramics (p each ≤0.0003). At scratch assay, HGF exhibited for all ceramics decreased relative distances of the scratch wound compared to the control from 24 to 48 h (p each <0.0001) with exception of VITA In-Ceram YZ after 48 h. HOK showed increased distances compared to the control for all ceramics after 48 h (p each <0.0001). At ToxiLight assay, a minimal cytotoxicity of the tested materials could be detected. CONCLUSIONS: Overall, significant influences of the investigated CAD/CAM zirconia ceramics on HGF and HOK could be shown. CLINICAL RELEVANCE: The analyzed zirconia ceramics could influence oral soft-tissue cells that might affect the esthetic outcome after implant placement using CAD/CAM zirconia abutments.

Interdevice agreement of eight equivalent dental color measurement devices.

OBJECTIVES: The reproducibility of electronic color-measuring devices used in dentistry refers to the consistency of measurements of a single device and also that between identical devices. This in vitro study evaluated the short-term interdevice agreement of eight equivalent dental measurement devices. METHODS: The short-term repeatability of eight identical VITA Easyshade Advance color measurement devices was evaluated. Each device was used to quantify the Commission Internationale de l'Eclairage (CIE) L*a*b* color coordinates of ceramic disks, designed in accordance with guidelines set by the VITA Toothguide 3D-Master shade tab organization. Statistical analysis involved calculating the intraclass correlation coefficients (ICCs) and color differences (ΔE*) for corresponding measurements taken by the devices. In addition, the mean color difference from the mean (MCDM) was calculated for each color. RESULTS: All devices showed high ICCs for the color coordinates (L = 0.996, a = 0.993, b = 0.999). The ΔE* by shade ranged from 0.62 to 1.67. The MCDM by color-measuring device ranged from 0.11 to 0.23. CONCLUSION: This in vitro study showed that the color-measuring devices used were suitable for determining shade with high repeatability. CLINICAL RELEVANCE: The high interdevice agreement of the VITA Easyshade Advance means that dental professionals can use this device independently, without compromising the consistency and quality of color measurements.

Influence of CAD/CAM all-ceramic materials on cell viability, migration ability and adenylate kinase release of human gingival fibroblasts and oral keratinocytes.

OBJECTIVES: The aim of this study was to analyze the influence of four CAD/CAM all-ceramic materials on cell viability, migration ability and adenylate kinase (ADK) release of human gingival fibroblasts (HGF) and oral keratinocytes (HOK). MATERIALS AND METHODS: HGF and HOK were cultured on disc-shaped CAD/CAM all-ceramic materials (e.max CAD LT, e.max CAD HT, Empress CAD and Mark II) and on discs made of tissue culture polystyrene surface (TCPS) serving as control. Cell viability was analyzed by using an MTT assay, and migration ability was investigated by a scratch assay. A ToxiLight assay has been performed to analyze the effect of all-ceramic materials on ADK release and cell apoptosis. RESULTS: At MTT assay for HGF, no significant decrease of cell viability could be detected at all points of measurement (p each > 0.05), while HOK demonstrated a significant decrease in cell viability especially on Empress CAD and Mark II at each point of measurement (p each < 0.001). Scratch assay demonstrated an increased migration ability for HGF on e.max CAD HT, Empress CAD and Mark II (p each < 0.001), whereas HOK showed a significantly decreased migration ability on all tested materials at all points of measurement (between -36 % and -71 %; p each < 0.001). At ToxiLight assay, only small cytotoxic effects of the all-ceramic materials could be investigated. CONCLUSIONS: This study disclosed significant differences in cell viability and migration ability of HGF and HOK on CAD/CAM all-ceramic materials. CLINICAL RELEVANCE: CAD/CAM all-ceramic materials can influence oral cell lines responsible for soft tissue creation which may affect the esthetic outcome.