Vita Classical Research Articles

A comparative study of shade-matching performance using intraoral scanner, spectrophotometer, and visual assessment

This study aimed to explore the clinical applicability of the shade-matching function in intraoral scanners. This study measured the tooth colors of maxillary anterior dentitions of 83 adults using visual matching, a spectrophotometer, and a scanner according to two color systems: VITA Classical (VC) and VITA 3D-Master (V3D). Agreement between each method was assessed by weighted Cohen’s kappa coefficient (KW, α = 0.05). For V3D, the overall agreement between the scanner and spectrophotometer (KW = 0.498) was higher than that between the scanner and visual matching (KW = 0.473). Similarly, the agreement between the scanner and spectrophotometer (KW = 0.283) was higher than that between a scanner and visual matching (KW = 0.140) for VC. Regarding tooth position, the highest agreement between the scanner and spectrophotometer was observed on the right central incisor (KW = 0.542) for V3D. Tooth color measurement with a scanner was comparable to that with a spectrophotometer, especially on the central incisors when using the VITA 3D-Master system. A scanner could serve as an alternative to a spectrophotometer for shade selection. However, color matching should still be visually verified.

The decomposition rate and bleaching efficacy of in-office bleaching gels with different pHs: a randomized controlled trial.

To evaluate the decomposition rate of active hydrogen peroxide (HP) and bleaching efficacy during in-office bleaching using high-concentration HP gels with different pHs. A randomized, parallel, double-blind controlled trial was conducted with 40 volunteers randomized into four groups (pH 5.4; pH 7.0; pH 7.7, and pH 8.0). During the first session in-office bleaching, approximately 0.01g of the gel was collected and titrated with potassium permanganate to obtain the concentration of active HP and pH values were measured using an electrode. Bleaching efficacy was assessed using a spectrophotometer [∆Eab, ∆E00, and WID], Vita Classical and Vita Bleachedguide scales [∆SGU]. The decomposition rate of HP concentration and pH values change were calculated using ANOVA one-way. The bleaching efficacy was assessed using two-way repeated measures ANOVA. Tukey's test was applied as a post-hoc test (p < 0.05). All gels experienced decreasing HP concentration over time. pH 5.4 gel showed greatest reduction after 50min (p < 0.001). pH 8.0 and 7.7 gels remained stable; pH 5.4 remained acidic, while pH 7.0 turned acidic (p < 0.001). No significant difference in bleaching degree was observed among gels. They all showed a similar and clinically important color change after two clinical sessions, remained stable 1-month post-treatment (p > 0.05). All bleaching gels kept at least 70% of their HP content after 50min, suggesting that there is a surplus of HP. They provided similar whitening efficacy 1-month after bleaching. It is possible that lower HP concentrations may be equally effective in achieving desired results while reducing the potential for side effects. RBR-35q7s3v.

Effects of sterilization on the color of ceramic shade guides used in fixed prosthetics

Aesthetic demands are very high in dentistry, and the color of prosthetic teeth is an important factor in success. Today, despite technological advances, the shade guide is still the most widely used instrument for determining tooth color. During the color selection process, the shade guide meets mucous membranes and saliva, making it a semi-critical material. To avoid any risk of cross-contamination, the shade guide can be sterilized. The aim of this study was to assess the impact of sterilization on the color of ceramic shade guides used in fixed prosthetics.: This was a quasi-experimental study. The study population was the sample teeth of the VITA 3D MASTER® shade guide and the VITA CLASSICAL® shade guide, except for the bleaching samples. Brightness, chroma, hue and delta E (∆E) were studied. Before and after each cycle of 120 sterilizations, measurements were taken using the VITA EASYSHADE V® Spectrophotometer. 2 to 2 comparisons of the mean brightness values show statistically significant differences between the two shades. For the same comparison, statistically significant differences were found for the shade and ∆E of the VITA 3D MASTER® shade guide. Sterilization leads to variations in shade guide color. Progressive wear could lead to color changes that are not clinically acceptable and could hinder the esthetic results of prostheses. It would be important to determine the number of sterilization cycles that should not be exceeded when using shade guides.

Bleaching efficacy of in-office dental bleaching with different application protocols: a single-blind randomized controlled trial.

This randomized controlled trial aimed to evaluate the equivalence in the color change, adverse effects, self-perception (AS) and the impact on oral condition (IO) of participants submitted to different application protocols of in-office dental bleaching. 165 participants were bleached with a 35% hydrogen peroxide gel (Total Blanc Office One-Step, DFL), according to the following protocols: (1) 2 applications of 20-min each (2 × 20min); (2) 1 × 40-min and; (3) 1 × 30-min. The color change was evaluated with the Vita Easyshade spectrophotometer, Vita Classical and Vita Bleachedguide scales. The intensity and risk of tooth sensitivity (TS) and gingival irritation (GI) were recorded using a 0-10 visual analogue scale (VAS). AS and IO was assessed before and after the bleaching procedure using the Orofacial Aesthetic Scale and Oral Health Impact Profile-14, respectively. Equivalent color change were observed (p < 0.001), with no significant difference between groups. The group 2 × 20min presented the highest risk of TS (76%, 95% CI 63 to 85), compared to the 1 × 30min (p < 0.04). The intensity of TS and GI and the risk of GI was similar between groups (p > 0.31). Irrespectively of the group (p = 0.32), significant improvements were observed for all items of AS and IO after bleaching (p < 0.02). The 1 × 30min protocol produced equivalent color change to the other bleaching protocols with reduced risk of TS and shorter application time. A more simplified application regimen of a single application of 30min yields effective bleaching and patient satisfaction while minimizing undesirable side effects and improving patient satisfaction.

Clinical Comparative Study of Shade Measurement Using Two Methods: Dental Guides and Spectrophotometry.

Tooth color is a determining factor in the fabrication of dental prostheses. The aim of the present study is to compare two measurement methods used in the field of dentistry: dental guides and spectrophotometry. A total of 2768 natural teeth were measured using the Vita Classical and Vita 3D-Master dental guides (Vita-Zahnfabrik, Bad Säckingen, Germany), as well as a Vita Easyshade Compact spectrophotometer (Vita-Zahnfabrik). The measurements were carried out by one operator under suitable illumination conditions at 5500 degrees Kelvin. The obtained results show that the measurements obtained with the Vita Classical dental guide classifies teeth into the A-B categories, while the spectrophotometer preferentially classifies teeth into the B-C categories. The correlation coefficients obtained with the dental guides ranged from -0.32 to -0.39 (p < 0.01), while those for the spectrophotometer ranged from -0.35 to -0.55 (p < 0.01). Therefore, we can conclude that the spectrophotometer is more reliable and reproducible in its measurements than the dental guides.

Color variation of composite resins in relation to the Vita Classical shade guide

Aim: The aim of this study was to verify the color variation between different composite resins and the Vita Classical Shade Guide. Methods: Two-millimeter thickness samples were made (n = 6) from eight commercial brands of composite resin (shade A2): Charisma (Kulzer), Forma (Ultradent), Harmonize (Kerr), Luna (SDI), Opallis (FGM), Oppus Bulk Fill (FGM), Vittra (FGM) and Filtek Z250 XT (3M ESPE). Specimens were stored in distilled water for 7 days and then polished. Color measurements of samples and A2 shade of the Vita Classical Shade Guide were performed using the Vita Easy Shade Advance 4.0 spectrophotometer on a black background. Color variations were calculated using the CIEDE2000 formula, considering values ≥0.81 being noticeable by the human eye and ≥1.77 being clinically unacceptable. Results were statistically analyzed with a 5% significance level. Results: Color variation (ΔE) of composite (E1 ) compared to the Vita Classical Shade Guide (E0 ) was greater than clinically acceptable for all the materials evaluated in this study. Forma (ΔE=2.08 ± sd=0.47) and Filtek Z250 XT (2.50 ± 0.20) had the smallest amount of color variation values found in the results. Harmonize (3.32 ± 0.63) presented values similar to Filtek Z250 XT, but it was worse than Forma. Vittra (3.51 ± 0.28), Charisma (3.80 ± 0.20), Opallis (4.24 ± 0.30) and Luna (5.67 ± 0.20) did not differ among each other and presented higher color variation than Forma, Filtek Z350XT and Harmonize. Oppus Bulk Fill (13.94 ± 1.12) was the composite with the greatest color variation. Conclusions: The findings in this study show that attention should be taken when using the Vita Color Shade Guide for composite shade selection.

Effect of topical application of ibuprofen/arginine on the in-office bleaching-induced tooth sensitivity: A randomized, triple-blind controlled trial

ObjectiveThe application of anti-inflammatories as topical desensitizers before dental bleaching is an approach to reduce bleaching-induced tooth sensitivity (TS). This randomized controlled trial compared the risk and intensity of TS and the color change resulting from in-office dental bleaching after using an experimental desensitizing gel containing ibuprofen and arginine. MethodsSixty-two participants with upper canine shades A2 or darker were randomly assigned to either the ibuprofen-arginine desensitizing group or the placebo group. The desensitizing gel was applied for 15 min before in-office bleaching with 35 % hydrogen peroxide gel for 50 min (2 sessions). To assess the absolute risk and intensity of TS, visual (0–10) and numeric rating (0–5) scales were used, and group comparisons were made using the McNemar test, Wilcoxon test, and paired Student t-test (α = 0.05). Color change was evaluated using Vita Classical, Vita Bleachedguide (ΔSGU), and Vita EasyShade (ΔEab, ΔE00, and ΔWID) before and one month after the bleaching procedure. Group comparisons for color change were done using a paired t-test (α = 0.05). ResultsThe odds ratio for TS was 0.14 [95 % CI 0.02 to 0.6], meaning lower odds of TS for the desensitizing gel. A lower intensity of TS was also observed for the experimental group (p < 0.005) up to 48 h after bleaching. All color evaluation tools demonstrated effective and similar whitening for both groups (p > 0.05). ConclusionsUsing the experimental desensitizing gel containing ibuprofen and arginine effectively reduced the risk and intensity of TS without compromising the bleaching efficacy. Clinical relevanceThe topical application of ibuprofen/arginine on the in-office bleaching reduced risk and intensity of bleaching-induced tooth sensitivity.

In-vivo repeatability of three intra-oral spectrophotometers.

The objective was to assess the repeatability of three spectrophotometers, based on the CIELCh factors and shadeguide reference measurements. Color analysis was performed using three devices: Rayplicker, Easyshade 4, and Easyshade V. Five repeated measures were performed by the same operator, on the right central maxillary incisor of 30 patients. The CIELCh factors were retrieved and the intra-class correlation was calculated. The Vita Classical and Vita 3D Master shadeguides were used to evaluate the respective Fleiss' Kappa factors. Rayplicker and Easyshade V demonstrated strong intra-class correlation based on the CIELCh factors: 0.98, 0.99, and 0.91 for Rayplicker, and 0.95, 0.99, and 0.93 for Easyshade V, for the L*, C*, and h* parameters, respectively. Regarding the repeatability of the shadeguide data, while Easyshade 4 had the best repeatability when using the Vita Classical as a reference, Rayplicker and Easyshade V showed better repeatability when using the Vita 3D Master. These findings suggest that both Rayplicker and Easyshade V are reliable devices for measuring CIELCh parameters. In terms of shadeguide references, the reliability of spectrophotometers is generally lower compared to the CIELCh measurements. Given their good repeatability, both the Rayplicker and the Easyshade V spectrophotometers are reliable tools for prosthetic dental practices.

Visual Tooth Color Determination with Different Reference Scales as an Exercise in Dental Students' Education.

Visual color determination (VCD) requires color competence and individual training. The aim of this study was to evaluate the deviations in students' VCD with two different reference scales. The research hypothesis was that none of the color references would provide a better result. Participants evaluated nine templates randomly using two reference scales (VITA-classical (VC) and 3D-Master-Toothguide (3DM_TG)). The color distance to the chosen color (ΔEab) was calculated in the CIELAB 2000. The sum's changes in the parameters (LCh°) represented the target variable. Results were evaluated with non-parametric, rank-scaled methods, utilizing the median with a 25%-75% quartile. The significance level (α = 0.05) is determined using the Student's t-test. The mean ± 95%CI (SD) was -1.27 ± -1.09 (3.18); the median ΔE00 was -1.49 (-1.97; 0.96) for dC3DM_TG. The determination with VC showed noticeable differences (dCVC), with a mean ΔE00 of 0.00 ± 0.00 (2.20) and a median ΔE00 of 0.00 (1.17; 1.71). The standard error was 0.19 for the dCVC and 0.27 for the dC3DM_TG. dC3DM_TG vs. dCVC showed significant differences at p < 0.001. The dental student's VCD resulted in color deviations, regardless of the reference template used. The color deviations in hue and chroma were comparable, regardless of the reference scale. VCD's early implementation in dental education is useful to avoid shade misjudgments and potentially expensive remakes of dentures.

THE POTENTIAL OF ACTIVATED CHARCOAL MADE FROM INDONESIAN JAMBI FOREST WOOD FOR HOME-USE BLEACHING TEETH

Introduction: Discoloration of the teeth can occur when stains damage the surface of tooth enamel. Developing treatment of teeth discoloration has increasingly due to discoloration teeth. Activated wood charcoal is one of the natural ingredients that can be used as an alternative to chemical home-use bleaching. Objective: The purpose of this study was to obtain the effectiveness of activated charcoal made from tembesu wood and bulian wood for home-use bleaching teeth Materials and Methods: This experiment was conducted at two locations: the Jambi Health Polytechnic Pharmacy Laboratory and the Jambi University Laboratory. It involved 60 samples, which were divided into six groups. The samples used in this research consisted of individuals with missing permanent teeth. The tooth color was assessed using the Vita Classical Shade Guide Tool. Charcoal derived from bulian wood and tembesu wood was mixed with toothpaste at concentrations of 10%, 20%, and 30%. Results: Our results showed a significant teeth whitening in both groups, namely Tembesu wood and Bulian. Particularly, we found that Tembesu wood, when used at concentrations of 10%, 20%, and 30%, is highly effective in teeth whitening. Specifically, at a 10% concentration of Tembesu wood, teeth whitening displayed a notable increase from day four to day 10. Meanwhile, at concentrations of 20% and 30%, teeth whitening exhibited significant improvement from day two to 10. In the case of Bulian Wood, teeth whitening was similarly effective for concentrations of 10% and 20%, with noticeable enhancement from day two to 10. For the 30% concentration, teeth whitening effectiveness increased substantially, starting from day one and continuing through day 10. Finally, no statistically significant difference between the two groups was found (p&gt;0.05). Discussion: Tembesu wood and bulian wood at concentrations of 10%, 20%, and 30% are effectively used for teeth whitening, and there is no statistically significant difference between the two groups (p &gt; 0.05).

Hybrid light applied with 37% carbamide peroxide bleaching agent with or without titanium dioxide potentializes color change effectiveness

BackgroundThe effectiveness of dental color change was assessed by incorporating titanium dioxide (TiO2) into 37% carbamide peroxide bleaching agent associated with hybrid light. MethodologyFifty bovine incisors were selected to receive the bleaching treatment, and separated into five groups (n = 10): 35% hydrogen peroxide (HP) (Whiteness HP, FGM/HP); 37% carbamide peroxide (CP) (Whiteness SuperEndo, FGM/CP); CP + hybrid light (HL) (CP HL); CP + 1% TiO2 (CP TiO2); CP TiO2 + hybrid light (CP TiO2 HL). The bleaching gels were applied to the dental surface for 30 min. Hybrid light (Whitening Plus, DMC/infrared laser diodes + blue LEDs +violet LEDs) was applied with 1 min of active light, alternating with 1 min of pause. A spectrophotometer (VITA Easyshade® Advance, Vita) was used to determine the color of the dental elements at baseline and time points after the 1st, 2nd and 3rd bleaching sessions. Color change effectiveness was evaluated using Vita Classical, CIEL*a*b*, WID and ΔEab, ΔE00 and ΔWID parameters. ResultsGeneralized mixed linear models for repeated measures (α = 5%) showed significant decrease in Vita Classical scores and a* and b* values, as well as an increase in L* and ∆WID values for all the groups. Higher color change values for ΔEab were observed for CP HL and CP TiO2 HL, while those of ΔE00 and ΔWID were higher for CP TiO2 HL at the end of the bleaching treatment. ConclusionHybrid light applied with TiO2 incorporated into CP potentiated the effectiveness of the color change in the tooth structure.

Different Methods for Assessing Tooth Colour-In Vitro Study.

Colour assessment using digital methods can yield varying results, and it is important for clinicians to recognize the potential variability intra and inter-device. This study aimed to compare the L*a*b* values of VITA Classical (VC) and VITA Toothguide 3D-MASTER (VM) guides using two methods, SpectroShade (SS) and eLAB. Thirty-four measurements per tab were performed by a single operator across three batches of each guide. Intraclass correlation coefficients (ICC) between batches were calculated. Values <0.5, 0.5-0.75, 0.75-0.9, and >0.90 were classified as poor, moderate, good, and excellent reliability, respectively. Results were reported as mean and standard deviation of the L*a*b* values and respective colour differences (ΔE00) for each tab and method. Statistical analyses were performed with an independent t-test, α = 0.05. ICC values between batches were excellent for all L*a*b*, except for a* component in eLAB. There were statistically significant differences between methods in most L*a*b* values. The intra-device mean ΔE00 was 0.5 ± 0.6 for VC, 0.5 ± 0.8 for VM in SS, 1.1 ± 0.8 for VC, 1.1 ± 0.9 for VM in eLAB. The mean ΔE00 inter-device was 4.9 ± 1.7 for VC, 5.0 ± 1.7 for VM. Both methods demonstrated good internal consistency, with high ICC values and low intra-device colour differences, but exhibited high variability between methods, higher for a* the component.

High-performance photoinitiating systems for new generation dental fillings.

To obtain new generation dental composites with improved performance properties compared to currently available dental fillings on the market and to determine the influence of new initiating systems on final product parameters such as degree of cure, hardness, color, and shrinkage. In order to verify the effectiveness of the developed initiating systems, typical spectroscopic, electrochemical, and kinetic studies using the real-time FT-IR method were shown. Moreover, paste dental fillings were prepared, the compositions were irradiated with the dental lamp, and the degrees of cross-linking were measured by Raman spectroscopy. The polymerization shrinkage was also determined using the rheometer. In addition, their hardness was examined on the Shore scale. Finally, the color analysis of the composites in the L*a*b*color space was compared with the VITA CLASSIC colorant. It was shown that, due to their excellent spectroscopic and electrochemical properties, new quinazolin-2-one can act as co-initiators in cationic and radical photopolymerization. It was demonstrated that the most effective composite containing the initiator system in the form of 3-SCH3Ph-Q, IOD, MDEA, and an inorganic filler as nanometric silica and a bonding agent is cured more than 90% after just 1 cycle of dental lamp exposure (30s), the hardness of the composite after curing on the Shor Scale is 82±4, and the polymerization shrinkage is less than 2.8%. The article demonstrates effective new initiator systems as an alternative to CQ/amine for obtaining new-generation dental composites. The developed dental composites are a big competition to the currently used dental fillings on the market.

Influence of coloring techniques on the surface characteristics and color stability of a monolithic zirconia ceramic

The color of monolithic zirconia restorations is obtained by presintering or postsintering coloring techniques. However, studies on the differences in surface characteristics and their influence on color stability are lacking. The purpose of this in vitro study was to evaluate the influence of shading and staining techniques for a zirconia ceramic on the surface characteristics and colorimetric parameters (color difference, translucency, and whiteness index) after exposure to coffee or red wine and then polishing. Ceramic disks (N=30; Ø10×1mm) were allocated into 3 groups: preshaded-shaded by the manufacturer (IPS e.max ZirCAD MT, shade A2); manually shaded-unshaded zirconia (IPS e.max ZirCAD MT, bleaching shade-BL) colored by the brushing technique, before sintering; stained-unshaded zirconia (IPS e.max ZirCAD MT BL) colored by the staining technique, after sintering. Spectrophotometric color assessments ensured the same initial perceived color (Vita Classical A2) for specimens included in the study (∆E00<1.77 acceptability threshold). Surface characteristics were assessed by scanning electron microscopy and atomic force microscopy. The specimens were immersed in coffee (n=5) or red wine (n=5) for 12 and 24 days and subsequently polished. The data were statistically and descriptively analyzed for color differences (∆E00), translucency parameters (TP00), and whiteness indexes for dentistry (WID), considering acceptability and perceptibility thresholds. The shaded groups found an irregular ceramic surface with uniformly sized zirconia crystals. The stained group found a glass-covered smoother surface. Significant alterations in color parameters (∆E00, TP00, WID) were observed with immersion in pigmenting beverages (P<.001) both after 12 days, and after 24 days. The shaded specimens had greater color alterations after immersion but benefited from the polishing procedure, which reduced color differences below an acceptable threshold in comparison with the baseline. Stained specimens had lower color alterations after immersion, but the polishing protocol was detrimental as it whitened the ceramic by subsurface exposure. The coloring technique influences the surface characteristics of zirconia ceramic and also the color parameters after exposure to colored beverages and polishing.

A Clinical Study Comparing the Maxillary Anterior Tooth Shade and Fabricated Crown Shade of the Western Uttar Pradesh Population to Commercial Shade Guides.

Background It is essential for dentists and technicians to work together to fabricate and create restorations that are a "perfect" shade match for a particular person. Thus, the Vitapan 3D-Master tooth shade system (Vita Zahnfabrik, Germany) was created and put into use in order to improve the accuracy of shade-selection operations. The objective was to visually assess the color of the maxillary anterior teeth in male and female subjects from various age groups in Uttar Pradesh, India. Materials and methods There were 150 patients in total, and they were divided equally into three groups of 50: Group I, which included patients aged 18 to 30; Group II, which included patients aged 31 to 40; and Group III, which included patients aged 41 to 50. Ceiling-mounted fluorescent lighting fixtures with PHILIPS 65 D tubes (OSRAM GmbH, Germany) were installed. Three medical experts provided their opinions as part of this research. The maxillary central incisor was placed next to tabs of various shades, and the doctors' final assessment was based solely on the central one-third of the face. From each of the two sample sets, a total of 30 patients were selected. Once the crown had been made from the prepared tooth of the patient, it was colored according to two shade guidelines (Vita Classic and Vita 3D Master). The three clinicians matched the shade of the manufactured crown with visual shade guides. For shade matching, a modified United States Public Health Service (USPHS) standard was employed. Results The Chi-square test was used to compare categorical variables across groups. According to the Vitapan Classic shade guide, 26% of Group I participants matched the first Hue group (A1), 14% of Group II participants matched the first Hue group (A3), and 20% of Group III participants matched the second Hue group (B2). Master shade guide for Vita 3D 26% of Group I participants matched with the second value group (2M2), 18% of Group II participants matched with the third value group (3L 1.5), and 24.5% of Group III participants matched with the third value group (3M2). Eighty percent of people who were matched to Alpha scored for crowns made using the Vita 3D Master shade guide, while 94.1% of people who were matched to Charlie scored for crowns made using the Vitapan Classic shade guide in a comparison of the two shade guides. Conclusion The majority of the shades obtained from the Vita 3D master shade guide were found to be 1M1 and 2M1 in the younger patients, 2M1 and 2M2 in the second age group, and 3L 1.5, 3M2 in the older age group. In contrast, the Vitapan Classic shade guide revealed A1, A2, A3, B2, C1, D2, and D3 as the predominant shades.

Physicochemical evaluation of hydrogen peroxide bleaching gels containing titanium dioxide catalytic agent, and their influence on dental color change associated with violet LED.

The purpose of this study was: 1) to analyze the physical-chemical properties of hydrogen peroxide (HP) agents at 7.5% (HP7) and 35% (HP35), and the association with or without TiO2 nanotubes; 2) to evaluate dental bleaching effectiveness by using HP7 and HP35 together with or without TiO2 nanotubes, and applied with or without violet LED (VL). 80 bovine incisors were treated according to groups (n=10): HP35; HP35+VL; HP35T (HP35+TiO2); HP35T+VL; HP7; HP7+VL; HP7T (HP7+TiO2); HP7T+VL. Bleaching effectiveness was measured at 4 time points according to the Vita Classical, CIEL*a*b*, CIEDE2000, and WID parameters. HP35, HP35T, HP7, and HP7T were evaluated for mass change, pH, mean particle size (P), polydispersity (PDI), and zeta potential (ZP), over 6 months of storage. The pH of HP35 thickener was higher when associated to TiO2. At baseline, both of the bleaching gels containing TiO2 had lower P, PDI, and PZ (p<0.05). All groups showed a significant decrease in Vita Classical color scores (p=0.0037). There was a higher L* value, and lower b* values for HP7 when associated to VL after the 3rd session. (p<0.05). HP35T showed higher color change (ΔEab, ΔE00), and lower a* value in the presence of VL (p<0.05). ΔWID presented lower values for both gels, when TiO2 was incorporated (p≤0.05). The incorporation of TiO2 to the bleaching gel showed good stability with minimal variations in physical-chemical properties. The color change in HP35 was more effective than in HP7, but the VL boosted the bleaching effectiveness of HP7, whereas TiO2 did not increase bleaching effectiveness.

Comparison between Visual shade selection and Instrumental Shade Determination using Intra Oral Scanner and Digital Spectrophotometer

Background: Improper shade selection is one of the most common causes behind restorations’ remake and patient dissatisfaction. Multiple protocols and devices have been proposed to address the limitations of visual shade selection. Objective: To compare the accuracy of dental shade matching gathered visually with both VITA Classical (VC) and VITA 3D-Master (V3D) shade guides with those obtained instrumentally with both 3Shape Trios 3 and VITA Easyshade® Advance 4.0. Materials and Methods: For visual shade selection (VSS), one- hundred participants from King AbdulAziz University, Faculty of Dentistry participated in the study and asked to select the shade of six masked shade tabs from both VC [A1, A2, B1] and V3D [1M1, 2M3, 3R1.]. Later, Instrumental shade determination (ISD) was completed by one experienced participant for six cycles using: VEasy and Trios 3. Results: Significant difference was found between VSS and ISD. The results suggested that although participants significantly preferred VC over V3D in terms of VSS, this did not improve the shade selection performance. Besides, in ISD, no significant difference was reported between VEsay and Trios 3. There was no statistical significance difference between neither Trios 3 when combined with VC and V3D nor between VEasy when combined with VC and V3D. VEasy showed the best shade selection performance when combined with V3D, although the difference was non-significant. Conclusion: The result of the present study supports the promising use of the intra oral scanner 3Shape Trios 3 and dental spectrophotometer VITA Easyshade® Advance 4.0. Combination with a visual selection method may result in more accurate and reliable results.

Clinical Testing of Walking Bleach, In-Office, and Combined Bleaching of Endodontically Treated Teeth.

Objective. The causes of internal posteruptive discoloration of teeth are bleeding, necroses, infections, and endodontic filling materials. The aim of this study was to establish the results of bleaching endodontically treated teeth using walking bleach, in-office, and combined techniques, using 30% carbamide peroxide and 35% hydrogen peroxide, as well as the effect of etiological factors, and the time elapsed after endodontic treatment on the success of bleaching. Materials and Methods. The research involved 30 endodontically treated teeth in healthy patients. Retroalveolar X-rays were taken to check the quality of root canal obturation. Endodontic treatment and obturation were carried out on the discolored non-vital teeth without any previous endodontic treatment. Before bleaching, two millimeters of the filling were removed from the root canal and the very entry into the canal was protected with glass ionomer cement. The teeth were divided into three groups, depending on the bleaching technique: walking bleach technique (10 patients), in-office technique (10 patients), and combined technique (10 patients). The teeth were bleached with 30% carbamide peroxide and 35% hydrogen peroxide. The bleaching procedure was repeated in all the patients three times. The color of all teeth was determined based on the Vita Classic guide before and after bleaching. The Χ2 square and Kruskal−Wallis tests were used to identify differences in teeth bleaching results. Results. A statistically significant difference (p < 0.05) was established between bleaching success and the time elapsed after endodontic treatment. There were no statistically significant differences observed between the bleaching success and etiological factors, bleaching techniques, or bleaching agents. Conclusions. The effectiveness of non-vital tooth bleaching is affected by the time elapsed after endodontic treatment.

Pigmentation techniques of a 4YSZ: Effect on the fatigue mechanical behavior of a 4YSZ adhesively luted onto dentin analog.

To characterize the effect of pigmentation techniques on the fatigue behavior of a 4YSZ ceramic adhesively luted onto dentin analog (glass fiber-reinforced epoxy resin). 4YSZ ceramic discs (Ø= 10mm, 1mm thickness) were allocated into 5 groups: Ctrl - unshaded (IPS e.max ZirCAD MT BL); Manuf - shaded by the manufacturer (IPS e.max ZirCAD MT A2); Brush - unshaded pigmented, pre-sintering, using a brush; Stain - unshaded pigmented, post-sintering, during glaze application; Brush+Stain - combination of both techniques. Color assessments ensured the same perceived color (Vita Classical A2). Dentin analog discs (Ø= 10mm, 2.5mm thickness) were obtained, paired with the 4YSZ discs, and adhesively luted using a resin cement. Cyclic fatigue testing (n=15) was run (20Hz; 10,000 cycles/step, initial load 200N; step-size 100N up to 700N; then 50N until specimen failure). Fractographic, roughness and topography analyses were performed. No statistical (p>0.05) detrimental influence were observed for fatigue outcomes (Ctrl = Manuf = Brush = Stain = Brush+Stain). However, the Brush+Stain technique induced inferior statistical (p<0.05) fatigue performance compared to Stain. All failures were radial cracks with origin at the ceramic intaglio surface. The staining technique triggered statistically higher roughness (p<0.05). Uniformly sized zirconia crystals were seen in the Ctrl, Manuf and Brush groups, and a smooth vitreous surface with encrusted pigments in the Stain and Brush+Stain groups. Pigmentation techniques (Vita Classical A2 shade) have no detrimental effect on the mechanical fatigue properties of 4YSZ ceramic adhesively luted onto dentin analog.

The accuracies of three intraoral scanners with regard to shade determination: An in vitro study.

To compare the accuracies of three intraoral scanners for shade determination function in vitro, and to preliminarily investigate the shade-matching characteristics of the three intraoral scanners. The shade of the middle third region of each shade tab on the Vita Classical A1-D4 shade guide (VC) was measured with a spectrophotometer (Vita Easyshade V, VE) and three intraoral scanners, including CEREC Omnicam (OM), 3Shape TRIOS 3 (T3), and TRIOS 4 (T4). A conversion table between VC values and CIELAB values was established from the database of VE to analyze the trueness. The reproducibility of the instruments was then compared by repeating the measurements five times. The mean color difference for each instrument was highest in the OM, followed by the T4, and lowest in the T3 and VE, respectively. The L* and a* value for OM, and the b* value for T4, were significantly different from those for VE (p <0.05). The reproducibility of the instrument was highest in the VE (Fleiss' kappa: 0.95), followed by the T3 (Fleiss' kappa: 0.89), T4 (Fleiss' kappa: 0.87), and OM (Fleiss' kappa: 0.78). Of the three intraoral scanners, the trueness was best on the T3. The reproducibility of all the instruments was excellent.