Statement of problem. Lighting conditions are an essential factor for accurately determining tooth color. However, the ideal lighting conditions for determining tooth shade are rarely met and are difficult to quantify. While the use of a standardized daylight lamp D55 can improve accuracy, its high cost limits its use in dental offices. The use of modern operatory treatment units for tooth color determination is promising, as they now allow for the adjustment of light source settings such as color temperature and intensity. However, studies are needed to determine whether they provide accurate color determination. Purpose. The purpose of this study was to assess the accuracy of visual tooth shade determinations under the adjusted light sources of 2 different dental treatment units in comparison with a standardized daylight lamp D55. Material and methods. Dental treatment units from 2 manufacturers KaVoLUX 540 LED (LK) and LEDview Plus (LDS) were tested. The light sources of these units were adjusted to match daylight conditions. A daylight lamp (Dialite Color 7; Eickhorst Co. KG) was used as a control (D55). A total of 49 participants (median age of 25 years, 30 women) underwent the Ishihara screening and received standardized training calibration. A total of 2205 clinical visual tooth shade determinations were performed with the Toothguide Training Box using the Vita 3D-Master shade guide under the 3 different lighting types. Each participant had 15 color determinations made under each of the 3 light settings. Color differences were analyzed by using the Kruskal-Wallis, Wilcoxon rank-sum, and chi-squared tests (alpha=.05). Results. The type of lighting used for tooth shade determination had no significant effect on the accuracy of selected shade based on the Delta E00 metric (P=.133). Perfect matches were achieved in 50.8% of the cases under LK, 49.8% under LDS, and 53.6% under D55 light, with no significant difference among percentages (P=.315). Although there was a significant difference in time elapsed for shade determination by light type (P=.004), this difference was not clinically relevant (20.8 seconds for LK, 23.9 seconds for LDS, 21.9 seconds for D55). Conclusions. The accuracy of color determination for both examined dental operatory lamps was found to be comparable with that of the standard D55 daylight lamp when adjusted to specific settings. (J Prosthet Dent 2025;133:238-245)

Matching tooth color with restoration is one of the most difficult tasks in restorative dentistry. One of the important aspects of dental education is teaching and learning color matching. The purpose of this study was to investigate the effect of the teaching method on improving the ability to determine color by dental students. In this study, dental students were randomly divided into two groups. The first group was taught the methods of tooth color matching in person and practically. In the s

Statement of problem. Monolithic zirconia restorations have become popular because of their excellent mechanical properties and acceptable esthetics. While the biomechanical properties of zirconia have been investigated, research into their esthetic properties is sparse. Zirconia can be colored by infiltration before sintering, although how occlusal adjustment can affect restoration color is unclear. Purpose. The purpose of this in vitro study was to analyze the color of differently characterized monolithic white and precolored zirconia specimens after standardized grinding. Material and methods. White and precolored monolithic zirconia plates (Cercon ht) (n=36) were stained by infiltration with target colors Vita A2, A3.5, and A4. In a standardized experimental arrangement, all plates were ground in 9 steps, and the color was measured with a spectroradiometer at each step. Color differences (Delta E-00) were analyzed by using regression analysis, the Kruskal-Wallis test, and the inverse prediction with confidence intervals (alpha=.05). Results. Mechanical material removal had a significant effect on the color stability (P<.05) of both white and precolored monolithic zirconia. For each grinding step and each target color, the precolored groups had a significantly lower Delta E-00 mean than the white groups (P<.05), except at the 20-mu m step for groups W-A4 and P-A4 (P>.05). For target color A2, the difference was significant with P<.001 at all 9 grinding steps. For target color A3.5, the difference was significant with P=.003 at grinding level 20 mu m, and P<.001 for all other grinding steps. For target color A4, the difference was not significant with P=.603 at grinding level 20 mu m, whereas the difference was significant with P=.007 at grinding level 50 mu m, and with P<.001 for all other grinding steps. Conclusions. Precolored zirconia had less color change after grinding than white zirconia. This study established grinding depths for white and precolored zirconia corresponding to color perceptibility and acceptability thresholds.

Objective To evaluate the repeatability, interexaminer, and interdevice reliability of two clinically applicable spectrophotometers under laboratory and clinical conditions. Material and Methods For the in vitro part of the study, measurements were performed by the use of Vita Easyshade Advance 4.0 (ES-A) and the Easyshade V (ES-V) at identical positions on different shade tabs (3D-Master; Vita Zahnfabrik, Bad Sackingen, Germany). To test repeatability, one shade tab was measured 50 times by one operator. To determine interrater and interdevice agreement, two operators used both devices to perform 10 measurements on five different shade tabs. Clinical interdevice and interexaminer reliability was checked with a positioning jig used (15 participants). Measurement accuracy of both devices was evaluated for the recommended color of shade tabs. Results Repeatability of results from both Easyshades was excellent for all color components (maximum deviation between measurements was <= 0.1 units). Interrater agreement was also perfect (intraclass correlation, ICC = 1.000). Interdevice agreement was lower, but still good (ICC >= 0.834). In the clinical environment, interrater and interdevice agreements were similar (ICC > 0.964 and ICC > 0.873). Accuracy was satisfactory for both devices, with both observers in full agreement for nearly 80% of ratings. Conclusions Both Easyshades produced reliable and accurate measurements and can therefore be recommended for clinical determination of tooth color. Clinical Significance The outcome of this study might help clinicians estimate the performance of a new digital shade determination device.

OBJECTIVES:The purpose of this study was to analyze the color infiltration in monolithic zirconia after grinding, which plays an essential role in the color stability of restorations after occlusal adjustment.METHODS:One hundred and eight white zirconia plates (36 Dentsply Sirona-Cercon high translucency [C], 36 Zirkonzahn-Prettau [P], 36 Zirkonzahn-Prettau anterior [Pa]) were stained by infiltration with target colors Vita A2, A3.5, and A4. In a standardized experimental setup, all plates were grinded in nine successive steps (from baseline to 500 μm), and color was measured with a spectroradiometer at each grinding step. Color differences ΔE00 between initial color and after each grinding step were calculated. The data was analyzed using regression, Kruskal-Wallis test, inverse prediction, and simultaneous 95%-confidence intervals.RESULTS:Grinding had a significant effect on color stability across all zirconia types and target colors (p < 0.001). At each cut level and target color, ΔE00 means for groups C, P, and Pa were statistically different (p < 0.05). Among the three zirconia types, Pa had the lowest ΔE00 mean score for cut levels 20-100 μm for A2 and between 50 and 300 μm for A3.5 and A4. For all other cut levels, differences between Pa and P were not significant (α = 0.05). C had the largest mean ΔE00 except for A4 until 100 μm, where it was second best.CONCLUSION:Zirconia type had a significant effect on the color infiltration depth across all target colors. Pa showed the best color stability until 150 μm material reduction, whereas C presented significantly less color stability than the other two zirconia materials.CLINICAL SIGNIFICANCE:Color stability is important for minimizing the risk of restoration failure due to unacceptable color changes after grinding. Pa is less susceptible to color change and has an additional buffer of 60 μm until exceeding the color acceptability threshold. When higher flexural strength is needed, P is to be preferred.

Objective To meet esthetic requirements, monolithic zirconia can be stained by color-infiltration. However, adjustments of occlusal surfaces are often necessary, leading to demasking effects if too much of the color-infiltrated layer is removed. The effect of subsequent material removal on color stability of individually stained zirconia is analyzed here. Materials and methods Thirty-six white zirconia disks were divided into three groups. Standardized staining strategies for tooth colors VITA A2, A3.5, and A4 were developed and applied to the disks. Samples were grinded in nine successive steps from 20 to 500 mu m. A spectroradiometer was used to measure the color differences after each step. Regression analyses were performed for color differences from baseline as a function of depth of material removal. Depth of material removal resulting in color changes surpassing the acceptability threshold of Delta E-00= 1.8 was estimated using inverse prediction. Results Up to 500 mu m material removal, color difference Delta E(00)changes linearly with the depth of material removal (P < 0.05). Regression analyses showed coefficients of determination (R-2) of 0.97 (VITA A2), 0.87 (VITA A3.5), and 0.96 (VITA A4). Acceptability threshold was surpassed at 62, 87, and 92 mu m, respectively. Conclusions Discolorations occur within clinically relevant occlusal adjustments of <100 mu m. The effect is more severe with lighter, less saturated tooth colors. Clinical significance Staining that is resistant to occlusal adjustments and abrasion is only possible if the staining solution infiltrates sufficiently deep into the ceramic structure. This study provides for the first time in the literature numerical values that describe the thresholds of acceptability of color differences in zirconia ceramics. These values are essential because they determine the extent of possible occlusal adjustments, and thus the color stability. Further research is necessary to improve the infiltration depth of staining solutions.

OBJECTIVES:To evaluate the effect of small-group education including practical training on dental students' shade determination performance compared with a control group.METHODS:Sixty-three non-colour-blind preclinical students were asked to participate and belonged to an intervention (n = 31) and a control (n = 32) group, respectively. All students received a lecture on dental shade determination. The members of the intervention group were educated and practically trained in small groups in addition. Ten volunteers, each with unrestored upper right middle and lateral incisors, were recruited. The students of both the intervention and control groups were then asked to determine the colour of the volunteers' test teeth using the 3D-Master shade guide (Vita Zahnfabrik, Bad Säckingen, Germany) under artificial daylight illumination. For analytical purposes, the CIE L*a*b* coordinates were obtained using a spectrophotometer. Colour differences, ΔE, between all shade tabs selected by the students and the natural teeth were calculated. ΔE observed in the intervention and control groups were compared using t tests. In addition, a multi-level regression model was adjusted for age and gender.RESULTS:Mean (SD) ΔE between the shade tabs selected by the students and the natural teeth in the intervention and control groups were 3.8 (2.1) and 4.3 (2.3), respectively (P < .001). The effect of group membership was reproduced in multivariate analysis whereas age and gender did not reach statistical significance.CONCLUSIONS:With more intensive education and practical training the ability to perform clinical shade determinations improved for students without previous clinical experience. The results obtained support the idea of implementing thematic small-group education in the dental curriculum.

Objective To assess surface discoloration of four enamel sealants based on different chemical compositions after exposure to artificial aging and staining solutions. Furthermore, their cleanability after polishing will be evaluated. Materials and Methods Selected sealants were a composite resin-based sealant with fillers (Pro Seal), a composite resin-based sealant without fillers (Light BondSealant), a resin-modified glass ionomer-based sealant (ClinproXT Varnish) and a silicon-based sealant (Protecto). Natural teeth served as medium. Immersion solutions were water, juice, tea, and turmeric. In a standardized setting, all samples were measured seven times with a spectroradiometer (Photoresearch PR670) at baseline, after thermocycling; 7 days; 2 and 4 weeks of immersion; and after finally polishing. Results Thermocycling had no significant effect on color stability. After exposure to staining solutions, all sealed surfaces showed significant color changes. Color change predominately occurred for all sealants in the first week of staining (P <= .01). Best resistance to staining decreased as follows: Protecto > Light Bond Sealant > ProSeal > Clinpro XT Varnish. Surface cleaning by polishing significantly reduced the color change. Conclusion Sealed enamel surfaces are prone to discoloration, which is most prominent in filled composite and glass-ionomer-based sealants. Staining can be reduced by polishing; however, in this in vitro setting the original color could not be restored. Clinical Significance Enamel sealants might exert adverse effects in terms of discoloration. This should be taken into consideration by clinicians and patients, particularly when sealants are applied in esthetically critical areas.

The objective of the study was to investigate the clinical outcome for electroplated telescopic removable dental prostheses (E-RDPs) with zirconia primary crowns.

The purpose of this in vitro study was to evaluate the effect of enamel sealants on bleaching of natural teeth by use of 40 % hydrogen peroxide in a dental surgery. The color stability of the results from bleaching was, furthermore, determined 10 months after the bleaching procedure. In a standardized setting, four sealants (Pro Seal®, Light Bond™ Sealant, Protecto®, and Clinpro™ XT Varnish) were applied to and removed from human teeth in accordance with the manufacturer’s instructions. Natural teeth served as medium; half of the teeth were sealed and the others served as controls. Hydrogen peroxide gel (40 %; Opalescence Boost; Ultradent Products, South Jordan, UT, USA) was used as bleaching agent. Color measurement was performed with a spectroradiometer (Photoresearch PR670) before the bleaching process (T1) and 24 h (T2) and 10 months (T3) after bleaching. The spectroradiometer results were expressed by use of the Commission Internationale de l’Éclairage (CIE) L*a*b* color notation. The L*, a*, and b* values of the sealed and the unsealed surfaces were not significantly different at any time during the study (p > 0.05), irrespective of the sealant used. Ten months after the bleaching process, mean L*, a*, and b* values were lower than at 1-day post-bleaching; the mean value of ΔE between 1-day post-bleaching and 10 months post-bleaching was 2.46 (±3.1). The results of the study suggest that the effectiveness of professional tooth whitening is not appreciably affected by the application of the four sealants tested.

OBJECTIVE:To evaluate changes in tooth color for 2 age cohorts (younger cohort, YC: 1950-1952; older cohort, OC: 1930-1932) over a mean observation period of 8 years.MATERIAL AND METHODS:Sixty-one participants with 106 upper central incisors were subjected to baseline and follow-up examinations (YC: n = 46/OC: n = 15). International Commission on Illumination color coordinates of 1 or 2 unrestored test teeth for each participant were recorded by use of a spectrophotometer (VITA Easyshade 1) during both measurement times. Changes of color coordinates during the study period were evaluated by use of generalized linear mixed models with the variable "participant" as random effect. ΔEab and E2000 color differences were calculated between baseline and follow-up.RESULTS:Significant changes in color coordinates were observed, with the exception of lightness in OC. The direction of the changes depended on the cohort. A decrease of lightness (value) was observed in YC (ΔL = 4.0; P < .001) whereas in OC chroma increased (ΔC = -3.3; P < .001). For both groups, a significant shift to more reddish tooth colors was observed. In almost all cases, color differences between baseline and follow-up exceeded the 50:50 acceptability thresholds for color differences (ΔE = 2.7) in both YC (≈90%) and OC (≈80%).CONCLUSIONS:For both quinquagenarians and septuagenarians, clinically relevant changes in tooth color were observed after a decade; these could affect the long-term success of prosthetic restorations in terms of a satisfactory color match between natural teeth and dental prostheses. In contrast with the findings of cross-sectional studies, the changes were partially age-group-specific.CLINICAL SIGNIFICANCE:Tooth color can change over a decade. When fixed dental prostheses are planned, one should consider that changes of tooth color could lead to mismatch between a restoration and adjacent teeth during the period in clinical service.

Poor oral health conditions are well documented in the institutionalized elderly, but the literature is lacking research on relationships between dementia and periodontal health in nursing home residents. The purpose of this cohort study, therefore, was to assess whether dementia is associated with poor oral health/denture hygiene and an increased risk of periodontal disease in the institutionalized elderly. A total of 219 participants were assessed using the Mini Mental State Examination (MMSE) to determine cognitive state. According to the MMSE outcome, participants scoring ≤20 were assigned to dementia group (D) and those scoring >20 to the non-dementia group (ND), respectively. For each of the groups D and ND, Gingival Bleeding Index (GBI) and Denture Hygiene Index (DHI) linear regression models were used with the confounders age, gender, dementia, number of comorbidities and number of permanent medications. To assess the risk factors for severe periodontitis as measured by the Community Index of Periodontal Treatment Needs, a logistic regression analysis was performed. Statistical analysis revealed no significant differences of GBI as well of DHI for demented and healthy subjects (p > 0.05). Severe periodontitis was detected in 66 % of participants with dementia. The logistic regression showed a 2.9 times increased risk among demented participants (p = 0.006). Oral hygiene, denture hygiene and periodontal health are poor in nursing home residents. The severity of oral problems, primarily periodontitis, seems to be enhanced in subjects suffering from dementia. Longitudinal observations are needed to clarify the cause–reaction relationship.

The objective of this study was to evaluate the repeatability, inter-examiner and inter-device reliability, and accuracy of the new VITA Easyshade Advance (ES-A) spectrophotometer in comparison with the Easyshade Compact (ES-C).

Für den Erfolg einer zahnärztlichen Restauration spielt neben der Funktion selbst auch die erzielte Ästhetik eine entscheidende Rolle. Durch die Gegenwärtigkeit und Wertung des ästhetischen Aspekts in Medien und Gesellschaft findet eine Sensibilisierung statt, sodass dem Schönen und der Harmonie ein hoher Stellenwert zugeteilt wird – sei es im sozialen, kulturellen oder medizinischen Bereich. Auf dem Gebiet der Zahnmedizin spielt die Ästhetik für die Zufriedenheit der Patienten mit einer Restauration eine wesentliche Rolle, wobei die Zahnfarbe eine Schlüsselposition einnimmt.

Abstract Objectives. Because of its good matching performance the VITA 3D-Master shade guide (3D) is frequently used for determination of tooth color. Numerous composites/ceramics are, however, available in VITA Classical (VC) shades only. The objective of this study was to investigate the possibility of performing a shade match with 3D Master and converting this result via a table in a VC shade (indirect method) without this resulting in an apparent inferior shade matching in comparison with direct shade matching with the VC. Methods. Experiments were performed with an artificial, computer-generated tooth color space. Conversion tables were generated by calculating the color difference (ΔE) between a 3D shade and the closest VC shade (simple conversion table) and with the aid of optimization procedures. Statistical differences between the direct and indirect methods and between the indirect methods were assessed by use of a U-test. Results. Median ΔE was 2.38 for direct matching with the VC and 2.86 for indirect matching by use of a simple conversion table (p < 0.01). Optimized tables performed slightly better (median ΔE = 2.81). Conclusions. Within the limitations of the study, it is usually possible to determine tooth color with the 3D and convert it, via a table, into a VC shade without adding a clinically apparent error to the direct shade match with the VC.

Statement of the problem. An important aspect of dental education is teaching and learning shade matching. Objective. To assess the success of two different strategies for learning shade matching. Materials and methods. Seventy-one pre-clinical students (mean age 23; 33.3% men) were divided into two groups. One group (TTB) formed teams of two and they matched three pre-determined teeth on each other using the 3D-Master shade guide. After this exercise, they learned shade matching using a standardized device (Tooth Guide Training Box, TTB) by matching shade tabs in an artificial environment. The other group (GL) matched tooth color in a pre-defined clinical setting in groups of four students. After this, they matched the same teeth as before training, again in groups of two, similarly to group TTB. The reference tooth color was determined by two experienced prosthodontic clinicians. The L*a*b* values for the tabs were provided by the manufacturer and the color difference (Delta E-ab) between the chosen tab and the reference was calculated. Linear general estimation equation models were used for statistical evaluation (p = 0.05). Results. In the TTB group, the difference between Delta E-ab values before and after training was 0.03, which was not significant (p = 0.927; 95% CI: -0.70/0.77). In the GL group, Delta E-ab was 0.98 smaller after training, which was significant (p < 0.001; 95% CI: 0.50/1.50). Conclusion. The ability to match tooth color could be improved by using a group-learning approach in a clinical setting and implementation of such a training session should be considered in undergraduate and postgraduate dental education.

INTRODUCTION:An objective structured clinical examination (OSCE) has been implemented in preclinical dentistry. It was taken at an early stage (propaedeutics course). The objectives of this study were to evaluate the reliability, validity, and feasibility of the examination, and the effect of circuit number on OSCE score.METHODS:The OSCE was designed by an expert committee on the basis of pre-reviewed blueprints and checklists. Eleven stations formed an interdisciplinary circuit. Six groups of students (n = 62) passed sequentially round the same circuit. Statistical analysis was performed by using SPSS. Reliability was determined by measurement of internal consistency (Cronbach's α, Guttman's λ(2) ), standard error of measurement (SEM) (comprising generalisability index α, dependability index ϕ and pass 150;fail reliability p(c) ), consistency coefficient κ, item 150;scale correlation (Pearson correlation), and, because the unidimensionality of the stations could not be assumed, factor analysis including varimax rotation. Convergent validity (Pearson correlation, t-test), and predictive validity for future preclinical courses and the final preclinical examination were assessed by analysis of variance (ANOVA). The effect of the circuit number on score improvement was calculated, including a correction for the general competence of the students (ANOVA). Cost was calculated on the basis of the time invested.RESULTS:Fifty-three out of sixty-two students passed the OSCE (mean score: 67%, SD 7.7, range, 47-81). Scores for each station correlated significantly with total scores (r = 0.35-0.54, P < 0.01). For internal consistency, α = 0.75 (relative SEM 3.8) and λ(2) = 0.766. The dependability index was ϕ = 0.694 (absolute SEM 4.4), p(c) = 0.89 and κ = 0.61. Factor analysis yielded two components: dental-materials-oriented stations and all other stations (explained variance 43%). Scores correlated significantly with success in passing practical tests (i.e. performing dental procedures under examination conditions) (known group validity, P < 0.01) and with scores for subsequent courses and the final preclinical examination (Physikum) (predictive validity, P < 0.001). Later groups performed 4% better on average (CI 95%: 1.2-6.8%; P < 0.01). The cost was 181 Euro per student.CONCLUSIONS:The OSCE is reliable and valid in the context of preclinical dentistry. The cost is substantial. The problem of improvement of students' results with ascending circuit number has to be addressed.

Aims. To evaluate the additional operating expenses caused by shade matching by dental technicians in the dental practice and by color changes of fixed partial dentures. Methods. A questionnaire was handed out to visitors of the 2010 ADT dental technician congress in Germany. Thirty-one completed questionnaires were evaluated. Results. Mean costs caused by shade matching and shade correction per month were 1269$ (SD = 1278$; n = 25) and per unit of FPD 9.32$ (SD = 8.89$). Conclusions. An improvement of shade matching, shade communication and reproduction should be made in order to minimize the considerable economic damage for dental laboratories.