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Objective: To assess dentine caries removal effectiveness (CRE) and minimal invasiveness potential (MIP) of carbide and polymer burs., Methods: Sectioned carious molars were photographed. Digital images were taken, before and after caries removal, using a Digital Single Lens Reflex camera. The following regions of interest were measured using visual criteria: Residual Infected Dentine (RI), Residual Affected Dentine (RA), Removal Sound Dentine (RA), Prepared Cavity (PC) and Removed Sound Dentine (RS). CRE was determined on basis of: relative residual infected dentine (RI/II), relative residual carious-affected dentine (RA/IA) and total relative residual dentine (RI+RA/II-IA). MIP was determined on basis of: infected dentine cavity size (PC/II), total relative cavity size (PC/II+IA), and corrected relative cavity size (PC-RS/II+IA)., Results: The polymer bur showed the highest preservation of carious-affected dentine after excavation, when the RA/IA ratio was studied. Both kind of burs showed similar values after assessing the RI/II and RI+RA/II-IA ratios. The infected dentine relative cavity size (PC/II) was higher when the carbide bur was used. Both burs attained similar PC/II+IA and PC-RS/II+IA ratios., Conclusions: Polymer burs accomplished the concept of minimal-invasive dentistry, showing its self-limiting ability. The minimal-invasiveness potential showed that carbide burs resulted in the worst compromise between effective and selective infected-caries removal., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Objectives: Determine visual 50:50% color difference acceptability thresholds (AT) for regions of the dental color space with varying chromaticity. Methods: A 40‐observer panel belonging to two different groups (dentists and laypersons) evaluated 144 dental resin composites pairs (divided in three different sets of 48 pairs according to chroma value: Low Chroma (LC), Medium Chroma (MC) and High Chroma (HC) placed 40 cm away and inside of a viewing cabinet (D65 Standard light source; diffuse/0° geometry). A Takagi–Sugeno–Kang (TSK) fuzzy approximation was used for fitting the data points and calculate the 50:50% acceptability thresholds in CIEDE2000. A paired t‐test was used to evaluate the statistical significance between thresholds differences and Bonferroni correction was applied. Results: The CIEDE2000 50:50% AT were ∆E00 = 2.84, ∆E00 = 2.31 and ∆E00 = 1.80 for LC, MC and HC sets of sample pairs, respectively. The 50:50% AT values were statistically significant between the different sets of sample pairs, as well as the 50:50% AT values obtained for different observer groups. Conclusions: 50:50% CIEDE2000 acceptability thresholds for dentistry are significantly different depending on the chromaticity of the samples. Observers show higher acceptability for more achromatic samples (low chroma value) than for more chromatic samples. Clinical Significance: The difference in the AT for distinct regions of the dental color space can assist professionals as a quality control tool to assess clinical performance and interpret visual and instrumental findings in clinical dentistry, dental research, and subsequent standardization processes. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the optical properties and the relative translucency parameter of Ceramill ZI White (3Y‐TZP) and Ceramill Zolid FX White (5Y‐PSZ) zirconia ceramic systems and compare them with those of the bovine dentin and enamel/dentin structures. Materials and Methods: 3Y‐TZP and 5Y‐PSZ zirconia ceramic systems were evaluated. A 0.5‐mm‐thick 3Y‐TZP (3Y‐NC.5), 0.5‐mm‐thick (5Y‐NC.5), and 1.4‐mm‐thick (5Y‐C.14) were used. A 0.5‐mm‐thick dentin specimens and 1.4‐mm‐thick enamel/dentin specimens (n = 5) were obtained from anterior bovine maxillary teeth. Scattering, absorption, transmittance, and albedo coefficient were calculated using Kubelka–Munk's model. Data were statistically analyzed using Kruskal–Wallis and Mann–Whitney tests (p < 0.001), and goodness‐of‐fit coefficient (GFC). Relative translucency parameter differences were evaluated using translucency thresholds. Results: Reflectance, scattering, absorption, and transmittance properties were wavelength dependent. Good matches (GFC ≥ 0.999) in spectral reflectance were observed between 0.5‐mm‐thick dentin and 1.4‐mm‐thick enamel/dentin, and 3Y‐NC.5 and 5Y‐NC.5. Scattering was the main optical extinction process during light interaction with zirconia and dental structures, as indicated by albedo coefficient. Translucency differences were acceptable only for 3Y‐NC.5 and the dentin structure, and 5Y‐C.14 and the enamel/dentin structure. Conclusions: Optical properties of 3Y‐TZP and 5Y‐PSZ dental zirconia differed from each other and from bovine dental structures. Nevertheless, 3Y‐TZP showed similar relative translucency parameter to bovine dentin. Clinical Significance: To achieve the best esthetic results in restorative dentistry, it is crucial for clinicians to know about the optical properties of 3Y‐TZP and 5Y‐PSZ and to be able to compare these properties with those of dental structures. [ABSTRACT FROM AUTHOR]

Usually, dentin and enamel shades are layered in dental restorations with the purpose of mimicking the natural appearance of teeth. The main objective of this study was to develop and assess accuracy of a color-prediction method for both monolithic and layered dental resin-based composites with varying shades and under different illuminants. A total of 15 different shades of VITAPAN Excell, VITAPAN Dentine and VITA Physiodens as well as VITA Enamel of five different thicknesses (0.5–2.5 mm range) were used to manufacture monolithic and layered samples. A non-contact spectroradiometer with CIE 45 ∘ / 0 ∘ geometry was used to measure the color of all samples over a standard ceramic black background. Second-degree polynomial regression was used as predictive method for CIE-L*a*b* color coordinates. Performance of predictive models was tested using the CIEDE2000 total color difference formula ( Δ E 00 ), while accuracy was evaluated by comparative assessment of Δ E 00 with corresponding 50:50% acceptability ( A T 00 ) and perceptibly ( P T 00 ) thresholds for dentistry. A mean color difference between measured (real) and predicted color of Δ E 00 = 1.71 , with 62.86% of the color differences below A T 00 and 28.57% below P T 00 , was registered for monolithic samples. For bi-layered samples, the mean color difference was roughly Δ E 00 = 0.50 , with generally 100% and more than 85% of the estimations below A T 00 and P T 00 , respectively. The predictive method allowed highly accurate color estimations for both monolithic and layered dental resin-based composites with varying thicknesses and under different illuminations. These results could be useful to maximize the clinical success of dental restorations. [ABSTRACT FROM AUTHOR]

Objective: Evaluate the effectiveness and color stability of bleaching techniques on blood‐stained teeth. Material and Methods: The teeth were stained by blood and allocated to groups: walking bleach, inside/outside, and in‐office bleaching. L*, a*, b*, C*, h° color coordinates were measured using a clinical spectrophotometer at baseline, weekly (T1‐T2‐T3), and at 1‐week (T4), 6‐months (T5), and 1‐year (T6) follow‐up evaluations. ΔEab*, ΔE00, and ΔWID were calculated between sequential evaluation timepoints and between baseline and each evaluation timepoint. Color coordinates and WID differences in each timepoint and technique were analyzed by Wilcoxon Signed Rank, Kruskal‐Wallis and Mann–Whitney U test, respectively. ΔEab*, ΔE00, and ΔWID were interpreted by color visual thresholds. Results: The techniques presented a significant increase in L* and WID and, a significant decrease in a* and b* until the completion of treatments. Statistical differences between the techniques for a*, b* and WID were observed from T1 until T3. All techniques demonstrated excellent effectiveness for ΔEab*, ΔE00, and ΔWID between baseline and each evaluation and follow‐up timepoints. However, at T6, it was possible to identify a rebound effect for all techniques. Conclusions: All bleaching techniques presented excellent effectiveness. The stability of the whitening produced was maintained for 6 months. Clinical Significance: Effective whitening of blood‐stained teeth was achieved using walking bleach (sodium perborate), inside/outside (hydrogen peroxide ‐ 7.5%) and in‐office techniques (hydrogen peroxide ‐ 35%). The bleaching techniques were effective after the completion of the treatments. A slight rebound was observed at 1 year follow‐up. [ABSTRACT FROM AUTHOR]