口腔仪器比色技术的研究进展

对于口腔临床医生而言,比色是一个比较复杂且较难解决的问题.视觉比色往往受到如光源、背景、年龄、性别和经验等诸多主、客观因素的影响,其比色的准确性和精确性有限.比色仪器有很多种类,最常见的有色度计、分光光度计、色光三原色(RGB)系统或它们的组合,其使用原理各不相同.由于仪器比色技术不受外界因素的影响,在临床上得到越来越广泛的运用,但其本身也存在一定的缺陷.本文就仪器比色技术的发展和现状作一综述.     

一步一步做好口腔美学修复临床比色

牙齿颜色是重要的美学参数, 前牙美学修复体尤其需要与相邻天然牙的颜色精确匹配。口腔医师对天然牙颜色的识别, 即临床比色, 是做好修复体颜色再现的基础。本文在讨论天然牙颜色特征以及影响临床比色各种因素的基础上, 阐述如何一步一步做好临床视觉比色和仪器比色, 并简要介绍比色训练方法和牙龈颜色的识别方法。     

仪器比色与视觉比色的临床研究

目的：通过临床实验比较视觉比色与仪器比色制作烤瓷修复的颜色准确性。方法：临床纳入26名自愿者,分别使用视觉比色和仪器比色的方法（Shade Eye NCC）选择修复体色调。相应的修复体制作完成并戴入口内,测色仪测量修复体及天然牙的色度学参数。计算两种选色方法制作的修复体与天然牙的色彩。结果：视觉比色方法修复体与天然牙色彩值为3.87（1.67）,而仪器比色的色差值为3.21（1.23）。配对t检验表明,两种比色方法制作的修复体与天然牙的颜色差别无统计学差异。结论：视觉比色与仪器比色方法制作的修复体颜色准确性相似。     

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颜色是影响美学修复效果的重要因素之一,仿真美学修复中的色彩复制过程包括色彩的定位、色彩的表达、色彩的再现三个步骤。色彩定位可采用视觉比色和仪器测色两种方法,影响视觉比色的因素包括比色工具、比色环境、色彩感知能力和比色训练情况,采用仪器测色时应注意其光学原理及仪器类型,并且在应用中注意正确的使用方法。     

2种比色法在金属烤瓷修复中应用的效果评价

目的对比视觉比色法和仪器比色法在金属烤瓷修复中的应用效果。方法对一段时间内126例需进行烤瓷修复的患者以随机的方式进行视觉比色法或用比色仪比色,根据"满意"、"可接受"、"不可接受"3个等级调查患者满意度,对2种比色法各个选项的结果以及前、后牙修复各个选项的结果进行统计分析。结果采用视觉比色法与仪器比色法在满意度上存在差别(χ2=6.220,P=0.045),采用视觉比色法时比色失败的构成比高于仪器比色法。前、后牙修复患者在满意度上也存在差别(χ2=6.094,P=0.048),前牙"不可接受"的构成比高于后牙修复患者。结论2种比色方法均可满足临床要求,患者对前牙的满意度低于后牙,仪器比色法在降低临床失败率上更具优势。     

口腔临床修复比色技术研究进展

修复体与天然牙颜色的协调程度直接关系到最终的修复效果，比色是美学修复中颜色再现或复制的一个重要步骤。口腔比色涉及到天然牙色、照明条件、比色技术、对比效应和观察者多个环节，只有对各个因素进行深入了解，才能保证临床比色的准确性。笔者总结现阶段比较常用的比色方法，针对常用的比色板以及比色仪器的优缺点、比色技术的发展现状作一综述，为改进临床比色质量提供参考。     

牙科比色法研究进展

牙齿颜色的测定方法主要分为视觉比色法和仪器测色法两种。由于视觉比色受到光源、环境、辨色能力等众多因素影响而常使比色结果出现一定误差。现今仪器测色以计算机比色仪更新较快,功能日趋完善,但亦存在一定局限性。笔者对各类比色方法优缺点及比色技术研究进展做一综述。     

三种比色板在牙科比色中的临床效果分析

目的：对比研究Vita经典比色板、Vita3D-Master比色板和SHOFU NCC比色板在牙科比色中的临床效果,以指导临床和技工制作瓷修复体。方法：采用修复前比色、修复体制作完成后口腔外比色以及口腔内核对颜色的方法,对比三种比色板的比色效果。结果：修复体制作完成后,在口腔内、外核对颜色时,使用Vita3D-Master比色板和SHOFU NCC比色板的满意度均高于Vita经典比色板,而Vita3D比色板和NCC比色板之间无显著性差异。结论：Vi-ta3D-Master比色板和SHOFU NCC比色板颜色范围较宽,临床比色可以取得较好的效果。     

金属烤瓷冠内外染色技术的临床应用

金属烤瓷修复因其美观、舒适、耐磨、无异物感等优点,在口腔修复临床工作中被广泛应用.但是天然牙的颜色范围广,变化大,不同人种、地区、性别、年龄的牙齿,甚至不同部位的同名牙齿,其颜色都可能有差异[1],而且临床目前多采用视觉测色法进行人工目测比色,再加上比色板的局限性,往往不能达到令人满意的效果.     

电脑色度计与视觉比色准确性的比较

目的:评价一种供临床使用的电脑色度计(Shade Eye Ncc)测色的准确性.方法:以临床上最常使用的Vita Classical比色板为标准,使用Shade Eye Ncc对色片的色度值进行测量,如果测量结果和该色片的色度值相符,则认为测量正确,反之,则认为是错误的.共测量5个比色板80个色片,计算测量准确率.选择15名无视觉缺陷的受试者进行Vita-Vita实验来测试视觉比色的准确率.使用卡方检验对获得的结果进行统计处理.结果:Shade Eye Ncc色度计比色的准确率为45%,高于视觉比色的准确性(39.16%),但差异尚不具有显著性.结论:视觉比色的准确性在不同个体之间有很大的差异;Shade Eye Ncc比色显示出了高度的重复性;但就本次试验而言,其测量的准确性与视觉比色相比,差异尚不具有显著性.     

The Role of Intraoral Scanners in the Shade Matching Process: A Systematic Review

Purpose

The variation in findings with regards to the accuracy and precision of intraoral scanners for shade selection are no doubt confusing for clinicians who may find it difficult to make evidence-based decisions. The aim of this systematic review is to provide a comprehensive and in-depth assessment of available studies to determine the viability of using intraoral scanners for the purpose of shade matching. The PICO-guided research question is as follows: when shade matching, are intraoral scanners as valid as visual or other digital shade measuring devices in determining tooth colors.

Methods

Electronic databases including PubMed/MEDLINE, SCOPUS, EBSCO, Cochrane, and ProQuest were systematically searched for articles published between January 1, 2011 and December 30, 2021 using the main search terms: “intraoral scanners,” “scanners,” “TRIOS,” “CEREC,” “Planmeca,” “Medit,” “digital dentistry” in concurrence with one of the following keywords: “EasyShade” OR “shade selection” OR “shade matching” OR “shade” OR “tooth color” OR “tooth shade” OR “digital shade matching.” Bibliographies of included articles and the following journals were searched for relevant articles: Journal of Prosthetic Dentistry, Journal of Prosthodontics, Journal of Esthetic and Restorative Dentistry, Journal of Advanced Prosthodontics, and Journal of Dentistry. A total of 15 articles were included in the review.

Results

Intraoral scanners are highly repeatable for shade matching, and outperformed visual shade matching. Accuracy varied significantly between studies, with the majority recommending the use of visual shade matching to confirm/verify the intraoral scanner results. Setting intraoral scanners to the Vita 3D Master shade guide improved both accuracy and precision. Shade matching with intraoral scanners may be influenced by external factors such as ambient light sources and incorrect use or manipulation.

Conclusion

Intraoral scanners set to the Vita 3D Master shade guide may be used for shade matching, but shade should be verified with visual shade matching. Further studies are required to address limitations of current studies.     

In vivo spectroradiometric evaluation of colour matching errors among five shade guides

Summary  The purpose of this study was to evaluate the colour errors of visual shade selection by five different shade guides. The maxillary left central incisors of sixty participants were visually evaluated by two groups of prosthodontists, with different clinical experience. The shade selection results were recorded and the most selected tab was determined as the resultant shade for each tooth. If totally different opinions were obtained, consensus was needed to determine the resultant shade among the observers. The colour distributions ( L*, a* and b* ) of each tooth and shade tab were measured using a spectroradiometer. The coverage errors (CEs) of each shade guide and colour differences (Δ E values) between a tooth and the selected shade tabs were calculated. Two-way anova and Tukey's post hoc analysis were used to evaluate the differences of CE and Δ E values among shade guides and clinical experience ( α  = 0·05). Coverage errors and Δ E values in all of the five shade guide systems were all beyond the clinical threshold of 3·3 units. The consensus led to a better colour matching than that of the single decision group in Vitapan 3D-Master and Shofu NCC shade guides. A significant difference ( P  < 0·001) was found among Δ E values of the shade guide system and clinical experience. In conclusion, all five of the shade guide systems used did not achieve clinically compatible shade matching. However, the Vitapan 3D Master shade guide system resulted in the lowest CEs and Δ E values. Consensus could be helpful in enhancing the aesthetic results using Vitapan 3D Master and Shofu NCC shade guides.     

Repeatability and reliability of human eye in visual shade selection

Deficiencies in the human visual percep‐tion system have challenged the efficiency of the visual shade‐matching protocol. The aim of this study was to evaluate the repeatability and reliability of human eye in visual shade selection. Fifty‐four volunteering dentists were asked to match the shade of an upper right central incisor tooth of a single subject. The Vita 3D‐Master shade guide was used for the protocol. Before each shade‐matching procedure, the definitive codes of the shade tabs were hidden by an opaque strip and the shade tabs were placed into the guide randomly. The procedure was repeated 1 month later to ensure that visual memory did not affect the results. The L*, a* and b* values of the shade tabs were measured with a dental spectrophotometer (Vita Easyshade) to produce quantitative values to evaluate the protocol. The paired samples t‐test and Pearson correlation test were used to compare the 1st and 2nd selections. The Yates‐corrected chi‐square test was use to compare qualitative values. Statistical significance was accepted at P < 0·05. Comparing baseline and 1st month records, statistical significance (P < 0·001) was found among qualitative data regarding repeatability on a yes/no (1/0) basis, revealing a very low percentage of repeatability (11·1%). Comparing baseline and 1st month records, statistical significance was not found (P = 0·000) among the L*, a*, b* and ΔE variables. These results indicate that dentists perform insufficiently regarding repeatability in visual shade matching, but they are able to select clinically acceptable shades.     

带金属底冠的定制比色板与VITA比色板的色度学分析比较

目的 比较VITA比色板和带金属底冠定制比色板的颜色特性。方法 采用PR-650型光谱扫描色度仪分别对5套VITA比色板和5套带金属底冠的定制比色板进行9区颜色测量。结果 VITA比色板的色度值范围L*为56.86-73.86,a*为-1.29-3.69,b*为7.09-21.94,透明度为3.20-7.59;定制比色板的色度值范围L*为60.59-78.54,a*为-1.09-4.99,b*为7.60-22.35,透明度为0.23-10.98。与VITA比色板相比,定制比色板的L*、a*、b*较大,二者的透明度也存在差异,同名比色片间的色差值大于1.5 NBS。结论 VITA比色板和定制比色板的颜色存在差异,金属底冠对金瓷修复体的颜色有一定影响,在临床比色时应予以充分考虑。     

Comparison of visual shade determination and an intra-oral dental colourimeter

The choice of correct tooth shade for the fabrication of a restoration remains a challenge, even for experienced clinicians. The aim of this research was to evaluate and compare the precision of two different shade determination methods in terms of repeatability. Maxillary right central incisor of 10 patients was evaluated visually with the use of Vitapan Classical shade guide by five observers and instrumentally with the Vitapan classical shade guide values of ShadeEye NCC intra-oral colourimeter three times consecutively. The in vivo repeatability of methods were analysed with the spectrophotometric L*, a*, b* values of the shade guide (Vitapan Classical). Within the limitations of this study, the repeatability of instrumental (intra-oral dental colourimeter) and visual shade determinations were acceptable.     

Comparison of shade matching by visual observation and an intraoral dental colorimeter

The purpose of this study was to compare the applicability of two shade-matching approaches: Vintage Halo shade guide (visual method) and Shofu ShadeEye NCC colorimeter (instrumental method). Twenty participants' maxillary left central incisors were evaluated. Corresponding metal ceramic crowns were fabricated with each shade-matching approach. The colour distributions (L*, a* and b*) of the middle third region of each tooth and corresponding metal ceramic crowns were spectrophotometrically assessed. The colour difference (DeltaE) and colour distributions (DeltaL*, Deltaa* and Deltab*) between the tooth and the corresponding crowns were calculated. We found that the colour differences of both groups fell within the clinical unacceptable range (DeltaE > 2.75). Regarding DeltaE and the three colour distributions, no significant difference was found, expect for a* (P < 0.01). The shade matching difficulty degree was analysed through the agreements of visual shade selection. Within easy matching cases, the instrumental method achieved better results (P = 0.041). In conclusion, it is suggested that the reliability of shade matching can be ensured by neither the colorimeter nor the visual approach. However, the colorimeter can achieve better results within easy matching cases.     

一种数码图像比色法准确性的实验性研究

目的探讨一种数码图像比色方法的准确性。方法建立一种数码比色方法:自行设计一封闭的拍摄环境,从拍摄参数、光源、图像的校正、色度数据的转换计量等方面加以控制,以Vitapan 3D-master比色板为研究对象,在恒定拍摄条件下分别对比色片摄片,数码图像经调整后读取比色片中1/3色度值。在Excel中进行色差计算并筛选获得比色结果,与目测法和色度计法相比较。应用卡方检验对结果进行统计处理。结果数码图像比色法准确率(53.45%)高于目测法(41.61%)和色度计法(36.55%),差异有统计学意义(P<0.05)。结论该数码图像比色法的准确性高于目测法和色度计法。     

电脑比色仪测色准确性的评价

目的：评价Shade Eye电脑比色仪测色的准确性。方法：测试样本为Shofu比色片和Vita比色片。用Shade Eye电脑比色仪对两种比色片从A1至D4逐一测色。结果：对Shofu比色片测色调配对率为53．75％,对Vita比色片测色的色调配对率为56．25％。经x^2检验,两组之间无差异。对Shofu比色片测色错配色调多为B色调和C色调,对Vita比色片测色错配色调多为B色调和D色调。结论：Shade Eye电脑比色仪的测色准确性有待改进。     

Shade selection performed by novice dental professionals and colorimeter

The objective of this study was to test inter-observer variability in shade selection for porcelain restorations, using three different shade guides: Vita Lumin Vacuum, Vita 3D-Master and Procera. Nineteen young dental professionals acted as observers. The results were also compared with those of a digital colorimeter (Shade Eye Ex; Shofu, Japan). Regarding repeatability, no significant differences were found between the three shade guides, although repeatability was relatively low (33-43%). Agreement with the colorimetric results was also low (8-34%). In conclusion, shade selection shows moderate to great inter-observer variation. In teaching and standardizing the shade selection procedure, a digital colorimeter may be a useful educational tool.     

Differences between the human eye and the spectrophotometer in the shade matching of tooth colour

Objectives

The aim of this work was to assess the agreement between instrumental and visual colour matching.

Methods

Shade selection with the 3DMaster Toothguide (Vita-Zahnfabrik) was performed for 1361 maxillary central incisors and compared with the shade obtained with the EasyShade Compact (Vita-Zahnfabrik) spectrophotometer.

Results

We observed a greater correlation between the objective method and the subjective one in the colour dimension of lightness (Kappa 0.6587), followed by hue (Kappa 0.4337) and finally chroma (Kappa 0.3578).

Conclusion

The colour dimension in which the greatest agreement is seen between the operator and the spectrophotometer is value or lightness.

Clinical significance

This study reveals differences between the measurement of colour via spectrophotometry and the visual shade selection method. According to our results, there is better agreement in the value or lightness colour dimension, which is the most important one in the choice of tooth colour.