Resin infiltration versus fluoride varnish for visual improvement of white spot lesions during multibracket treatment. A randomized-controlled clinical trial.

AIMS: This study aimed to evaluate the visual improvement of resin infiltration of white spot lesions (WSL) during orthodontic treatment with the multibracket appliance (MBA) compared to fluoride varnish. METHODS: Patients aged 12-17 years with at least one WSL with an International Caries Detection and Assessment System (ICDAS) score of 1-2 during an active MBA treatment were included and randomized to receive either resin infiltration (Icon) or fluoride application (Flairesse). Standardized digital images were obtained before, one-day, one-week, one-month, three-months and six-months after treatment using a DSLR camera and a matching polarization filter. A grey reference card was used for color standardization. A Matlab routine was used to measure the color difference between adjacent healthy enamel and treated WSL. The independent-samples t-test was used for intergroup and paired-samples t-test for intragroup comparison. RESULTS: Images of 116 teeth from 36 patients were analyzed. The ΔE for the "Icon" treated WSL was smaller (T1ICON = 5.0 ± 1.4) than in the fluoride group (T1Fluoride = 8.4 ± 3.2). Caries infiltration significantly improved the aesthetic appearance of WSL (p < 0.001), which remained satisfactory at six months (T5ICON = 5.2 ± 1.6). CONCLUSION: WSL infiltration management during orthodontic treatment was superior to topical fluoridation in not only arresting the enamel lesions but also significantly improving the aesthetic appearance of demineralized regions around the brackets. CLINICAL RELEVANCE: WSL treatment in orthodontic patients is usually initiated after debonding. Research has shown that the earlier WSL is treated, the better the aesthetic outcome. There is limited data on the efficacy of resin infiltration of WSL during orthodontic treatment.

Illuminant metamerism between natural teeth and zirconia restorations evaluated with a chromatic adaptation transform.

STATEMENT OF PROBLEM: Little is known about the effect of illuminant metamerism between natural teeth and zirconia restorations, despite their increasing clinical popularity. PURPOSE: The purpose of this in vitro study was to compare illuminant metamerism between pairs of natural teeth and layered zirconia restorations and pairs of natural teeth and monolithic zirconia restorations under 10 different illuminants and analyze their metameric potential. MATERIAL AND METHODS: Spectral reflectance factors were obtained from 10 pairs of extracted natural teeth and layered zirconia restorations and 28 pairs of extracted natural teeth and monolithic multilayer zirconia restorations. Each pair showed a color match that was within the visual threshold for clinical acceptability (CIEDE2000≤1.8). A special index of metamerism for the change of illuminant (Milm) was calculated from the CIEDE2000 color difference equation. Descriptive statistics and the one-sample t test were used to analyze the results for the Milm and for both groups of layered and monolithic zirconia restorations (α=.05). RESULTS: Layered zirconia restorations reached a mean ±standard deviation value for Milm=0.3 ±0.2 and Milm=0.5 ±0.4 for monolithic zirconia restorations (P<.01). CONCLUSIONS: The effect of illuminant metamerism between natural teeth and zirconia crowns was weak and generally within the clinical acceptability limit.

Objective shade matching, communication, and reproduction by combining dental photography and numeric shade quantification.

OBJECTIVE: The subject of this case report is the application of a newly developed workflow for objective shade communication sans visual shade assessment or the use of shade guides. CLINICAL CONSIDERATIONS: Clinical complications stemming from issues relating to esthetic integration can present a burden on the restorative team, often resulting in strenuous relationships among its members. The faithful imitation of the optical appearance of dental hard tissues with direct- and indirect restorations has been at the center of interest in a great number of publications from the realm of esthetic dentistry over the past 40 years. The present report describes a new approach to objective shade communication, by transcending the role of dental photography from its purely descriptive purpose to the level of quantification, thus abandoning the use of the established shading regimes and replacing them with a patient personal shade recipe based on the CIELAB color space instead. CONCLUSIONS: Objective shade communication is possible with the eLAB system by combining numeric shade quantification with dental photography. CLINICAL SIGNIFICANCE: The eLAB system presents a viable alternative to the traditional approach to shade communication and shade matching in dentistry.

Bridging instrumental and visual perception with improved color difference equations: A multi-center study.

OBJECTIVES: This multicenter study aimed to evaluate visual-instrumental agreement of six color measurement devices and optimize three color difference equations using a dataset of visual color differences (∆V) from expert observers. METHODS: A total of 154 expert observers from 16 sites across 5 countries participated, providing visual scaling on 26 sample pairs of artificial teeth using magnitude estimation. Three color difference equations (ΔE*ab, ∆E00, and CAM16-UCS) were tested. Optimization of all three equations was performed using device-specific weights, and the standardized residual sum of squares (STRESS) index was used to evaluate visual-instrumental agreement. RESULTS: The ΔE*ab formula exhibited STRESS values from 18 to 40, with visual-instrumental agreement between 60 % and 82 %. The ∆E00 formula showed STRESS values from 26 to 32, representing visual-instrumental agreement of 68 % to 74 %. CAM16-UCS demonstrated STRESS values from 32 - 39, with visual-instrumental agreement between 61-68 %. Following optimization, STRESS values decreased for all three formulas, with ΔE' demonstrating average visual-instrumental agreement of 79 % and ∆E00 of 78 %. CAM16-UCS showed average visual-instrumental agreement of 76 % post optimization. SIGNIFICANCE: Optimization of color difference equations notably improved visual-instrumental agreement, overshadowing device performance. The optimzed ΔE' formula demonstrated the best overall performance combining computational simplicty with outstanding visual-instrumental agreement.

Determination of the spectrally resolved extinction coefficient of human dental enamel using collimated transmission spectroscopy.

OBJECTIVES: The determination of the extinction coefficient of human dental enamel to deliver further optical properties of enamel to improve the understanding of light propagation in teeth and to improve restoration materials. METHODS: The extinction coefficient was measured within a spectral range of 300-980 nm using a collimated transmission setup. 35 specimens from 16 donors were examined. The donors were categorized by age and the researched specimen were categorized by tooth type, tooth quality and lateral expansion of the enamel to clarify the influence of these parameters. RESULTS: The obtained spectrally resolved extinction coefficient was accurately described by a power law, which agrees with theoretical scattering models. The results were evaluated with regard to the influence of parameters such as subject age, tooth type, enamel sample quality and enamel width. For this purpose, both the average values of multiple measurements of a single sample in a defined spectral range as well as the curve slope of the averaged results versus wavelength were compared. SIGNIFICANCE: The results provide detailed information about the optical properties of human enamel. The wide spectrum investigated provides important information for the evaluation of the main scatterers and the optical impression under any light condition. However, the deviation of the extinction coefficient varies less between the mean values for the specimens grouped by several parameters than between the specimens themselves within a group. This indicates a unique optical behaviour for every specimen and this requires consideration in the development of artificial materials.

The effect of ultraviolet induced fluorescence on visually perceived tooth color under normal light conditions.

OBJECTIVE: Restorative and prosthetic materials should provide an appearance similar to natural teeth under all light conditions, including UV-rich environments and daylight. Various studies claim that UV-induced fluorescence makes teeth whiter and brighter in daylight. The aim of this paper is to determine experimentally the significance of tooth fluorescence in natural sunlight on perceived tooth color. METHODS: A total of 35 extracted, hydrated teeth without restorations or endodontic treatments were evaluated in an experimental setup. A UV/VIS spectrometer using a reflectance/backscattering probe was used to collect the reflected spectrum. Unfiltered and filtered sunlight was used for irradiation of the samples so as to use the combined ultraviolet and visible spectrum (UV/VIS) and the visible spectrum (VIS) exclusively. Color coordinates for each group were measured using the CIE L*a*b* 1976 system, averaged, and compared. RESULTS: The average color difference between both groups (UV/VIS and UV) was ΔE* 0.527. The average tooth color for the VIS group was L*VIS 72.21, a*VIS -2.42, and b*VIS 22.35, and for the UV/VIS group was L*UV/VIS 72.00, a*UV/VIS -2.47, and b*UV/VIS 22.44. SIGNIFICANCE: UV induced fluorescence from sunlight does not make teeth whiter and brighter.

[Light in Dental Photography]. / Fototipps: Licht in der dentalen Fotografie

Effective lighting is a key factor in achieving a good image, not just in dental photography. A variety of light sources can be used for this. It is important to know the colour quality of the light sources and adjust the camera accordingly. This helps to avoid unwanted alterations in colour. Lighting is crucial to a successful image. It controls not only the lightness or darkness of the image, but also the tone, feel and atmosphere of the picture. Manipulating the light, for example by using special filters, can also be a useful diagnostic tool for treatment.

eLABor_aid: a new approach to digital shade management.

Contemporary dental patients present with high expectations and demand seamless optical integration of restorative interventions. As a result, clinicians and technicians are required to develop methodologies that remain practical yet increase the accuracy and objectivity of shade analysis and estimation. There have been significant advances in digital technologies over the past 20 years, with digital photography being at the forefront. Digital photography has made an immediate and profound impact on applied clinical dentistry, primarily due to instantaneous image visualization and distribution. However, standardization protocols in terms of image acquisition and objective analysis remain equivocal. By utilizing reflective cross-polarized light digital photography with a standardized white balance gray reference card serving as the known reference, in conjunction with a specific digital single-lens reflex (DSLR) camera profile and digital photographic processing software working in the CIE L*a*b* (1976) color space, one can achieve standardized image acquisition and subsequent objective image analysis. The goal of this systematic approach is to identify the most efficient and effective means to generate consistent and optimum visual integration and restorative outcomes through numerical quantification, in order to enable clinicians and technicians to work predictably even when they are in different geographic locations.

The use of a standardized gray reference card in dental photography to correct the effects of five commonly used diffusers on the color of 40 extracted human teeth.

OBJECTIVE: The aim of this in vitro study was to investigate the color changes of human teeth caused by five different diffuser materials commonly used in dental photography, as well as software influence, and to confirm whether the use of a standardized gray reference card is effective in correcting these color changes during digital postproduction. MATERIALS AND METHOD: Forty extracted human teeth were obtained from a specialized oral surgery practice in Cham, Germany. Five commonly used diffuser materials were chosen to be investigated, which included: polyethylene (PET), White Frost photographic paper, LumiQuest polyamide (nylon) material, 80 gsm white printing paper, and 3M linear polarizing filter sheet used for cross polarization. A digital single-lens reflex camera (Canon EOS 5D MKII) was used, together with a twin flash suitable for macrophotography (Canon MT-24EX Macro Twin Lite). Images were tethered into Adobe Lightroom CC using the RAW format. A standardized gray reference card (WhiBal, Michael Tapes Design) was used for exposure calibration and white balancing. Classic Color Me- ter software (Ricci Adams, version 1.6 (122)) was used to obtain CIE L*a*b* values of the specimens before and after white balancing and exposure correction. RESULTS: All diffusers caused visually perceivable color changes on the extracted teeth: White Frost (ΔE* 1.24; sd 0.47), 80 gsm printing paper (ΔE* 2.94; sd 0.35), LumiQuest polyamide (ΔE* 3.68; sd 0.54), PET (ΔE* 6.55; sd 0.41), and 3M linear polarizing filter sheet (ΔE* 7.58; sd 1.00). The use of a standardized gray reference card (WhiBal) could correct these values below the visually perceivable threshold: White Frost (ΔE* 0.58; sd 0.36), 80 gsm printing paper (ΔE* 0.93; sd 0.54), LumiQuest polyamide (ΔE* 0.66; sd 0.58), PET (ΔE* 0.59; sd 0.33), and 3M linear polarizing filter sheet (ΔE* 0.53; sd 0.42). SIGNIFICANCE: The use of a standardized gray reference card with specified CIE L*a*b* values should be considered when diffusers are used in dental photography in order to reveal the color of preoperative situations (ie, shade documentation) and document postoperative results accurately.