目测法比色准确性的评估

目的:研究目测法比色的准确性.方法:采用Vitapan比色板对100颗上颌天然切牙进行比色,选定比色片标号.在CIE1976L*a*b*色度系统下,运用松风ShadeEye NCC电脑比色仪对天然牙和比色片进行颜色的测量和分析.结果:目测法比色所选色片与天然牙的色差为0.26～6.70,平均色差为1.78.比色片的明度值与天然牙的明度值有显著性的差异.结论:门诊医师所选比色片与天然牙间的颜色存在一定的差异.     

视觉比色机械训练系统对色彩识别能力的影响

目的：评价TTB视觉比色机械训练系统对受试者比色能力的影响.方法：使用TTB系统对102名受试者进行每周1次、共3周的视觉比色训练,记录每次TTB训练的成绩及时间,计算每次TTB测试的比色效率值.在训练前后均随机选29色Vita 3D-Master比色板的5个色标进行比色测试,计算比色平均色差及单项色彩因素选择正确率,做为培训前、后比色能力测试成绩.结果：TTB测试比色效率逐渐提高,三次测试效率之间的差异均有统计学意义（P＜0.01）;培训后比色能力测试中所选色片与目标色片的平均色差小于培训前比色平均色差,差异有统计学意义（P＜0.01）.经培训后受试学生对单项色彩因素选择正确率均高于培训前水平,差异有统计学意义（P＜0.01）.结论：视觉比色机械培训可提高受试者的色彩识别能力.     

口腔修复临床经验对比色准确性训练的影响

目的:观察口腔修复临床经验在比色准确性训练中的作用.方法:选择具备1～2年口腔修复临床经验的口腔医学生37名(A组)以及无口腔修复临床经验的口腔医学生57名(B组).每组学生一部分使用TTB训练,其余使用TT训练.训练前首先使用Vita 3D-master比色板作为比色工具,随机抽取10个比色板标准色标进行测试.然后对测试对象进行每周1次、连续3周的牙比色训练.每次训练完成后进行比色测试并计算比色准确率.采用SPSS16.0软件包进行非参数秩和检验,比较每次测试成绩的差异及A组与B组之间每次训练后测试成绩的差异.结果:临床经验组与无临床经验组训练前比色准确率分别为(65.67±20.48)％和(70.17±17.57)％.经过3次训练后,比色准确率分别为(78.91±22.82)％和(80.17±17.77)％.2组训练前及每次训练后比色正确率差异无显著性(P＞0.01).训练后与训练前比较,比色正确率提高,差异有统计学意义.结论:具有1～2年修复临床经验和无临床经验的口腔医学生之间,口腔修复临床经验对比色准确性无明显影响,TT/TTB系统的比色训练均能提高所有受试对象的比色准确性.     

Crystaleye电脑比色仪和目测法比色的临床效果比较

目的:比较Crystaleye分光光度计电脑比色仪比色和目测法的比色效果,探讨电脑比色仪临床使用的可行性.方法:随机选取前牙或第一前磨牙区的单颗Ni-Cr烤瓷全冠修复患者63例,分别用Vitapan classical比色板目测比色法和Crystaleye电脑比色仪比色,根据2种比色方法的比色结果,制作1组修复体(冠V和冠S).修复后,用Crystaleye电脑比色仪对每组修复体和比色参照的天然牙进行测色,计算每组修复体体部与天然牙体部的总色差⊿E值,采用SPSS13.0软件包对结果进行配对t检验.由患者(p)和医师(d)按照双盲法,分别对2套冠进行比色评价(Vp,Vd,Sp,Sd),对评价结果进行配对x2检验.结果:V组⊿E(3.13±0.80)和S组⊿E(2.68±0.72)的差异有统计学意义(P<0.001).比色评价上,Vp组和Sp组差异无统计学意义(P=0.035);Vd组和Sd组的差异有统计学意义(P<0.01);p组和d组差异有统计学意义(P<0.01).结论:Crystaleye电脑比色仪的比色效果优于肉眼比色,Crystaleye电脑比色仪可用于临床并辅助医师比色.     

Crystaleye比色仪比色与比色板比色的临床效果对七匕

目的：比较Crystaleye比色仪比色方法与Vita 3D Master比色板比色方法的临床应用效果.方法：对80例患者的103颗前牙采用随机分组的方法,分为两组,即比色仪组：40例患者（52颗前牙）;比色板组：40例患者（51颗前牙）.分别采用Crystaleye比色仪比色方法和Vita 3D Master比色板比色方法进行临床测色.制作修复体后,在口内再用C rystaleye比色仪对修复体和对照牙分别进行测色.分别计算两组修复体与对照牙的色差（△E）并评价患者对修复体颜色的满意度.结果：比色仪组的△E为（2.97±1.64）,比色板组的△E为（6.07±2.28）;t检验,差异有统计学意义（P＜0.05）.比色仪组的患者满意度整体水平高于比色板组;x2检验,差异有统计学意义.结论：Crystaleye比色仪与Vita 3D Master比色板相比：比色结果更准确,患者满意度更高.     

烤瓷修复体的比色方法及相关问题

烤瓷牙比色问题是目前审美性修复工作中的难点及热点,如何有效地进行临床比色、并使比色信息准确传递与再现是国内外学者们不断探索的课题.本文就现有的比色方法及相关问题作一综述,旨在为临床修复工作及科研提供更好的服务.     

比色板与电脑比色仪比色准确性的分析

目的 通过分析比色板与电脑比色仪比色的准确性,探讨电脑比色仪对比色板色标未能覆盖颜色的精确表达作用.方法 选取天然牙颜色分布相对均一的单颗前牙全瓷冠修复患者120例,按照随机数字表分为两组(V组和S组),每组60例.V组采用比色板,S组采用电脑比色仪,对患者的天然牙进行比色;再根据测色结果分为色标颜色组(V1、S1)和中间颜色组(V2、S2).修复后使用电脑比色仪对所有修复体及V组比色参照的天然牙进行测色,分别计算每组修复体中部与天然牙中部的总色差△E*ab,对结果进行配对t检验.结果 V组△E*ab(3.92±1.59)与S组△E*ab(2.23±0.96)的差异有统计学意义(P＜0.01);V1组△E*ab(2.29±0.88)与V2组△E*ab(4.42±1.42)的差异有统计学意义(P＜0.01);S1组△E*ab(2.12±0.84)与S2组△E*ab(2.27±1.01)的差异无统计意义(P=0.014).V2组AE*ab与S2组△E*ab的差异有统计学意义(P＜0.01);V1组△E*ab与S1组△E*ab的差异无统计学意义(P=0.698).结论 对于比色板色标未能覆盖的颜色,电脑比色仪的定位与表达比单纯用比色板比色更准确,利于指导修复体的颜色再现.     

牙科比色板和比色仪的研究现状

比色对于牙科医生来说仍然具有挑战性。牙科色彩学研究的不断深入促生了新型比色板和可用于临床的比色仪,这些比色板和比色仪的出现提高了牙齿颜色测量、交流和再现的成功率,但其应用和研究仍存在一些问题。本文就比色板和比色仪的研究现状作一综述。     

体外模型评估Cyrstaleye比色仪的可靠性和准确性

目的:通过体外模型,评估Crystaleye口腔比色仪的可靠性和准确性,探讨该仪器临床应用的可行性。方法:在可靠性实验中,随机选取Vita classical,Vita 3d master和Shofu vintage比色板各一块,用Crys-taleye比色仪对三块比色板上的各色片依次测量十遍,记录比色结果。在准确性实验中,随机选取上述三种比色板各三块,用Crystaleye比色仪对比色板上的各色片依次测一遍,记录比色结果。用t test和1-w ayANOVA统计方法分别对同一比色板颈中切三部分及不同比色板相应颈中切三部分之间的可靠性和准确性结果做统计分析。结果:Crystaleye比色仪对三种比色板各色片颈中切三部分均有较高的可靠性,尤其中1/3的可靠性最高,范围是84.62%-91.25%。Crystaleye比色仪对三种比色板色片中1/3有较高的准确性,其范围是70.83%-87.18%,与切1/3和颈1/3的准确性差异有统计学意义。Crystaleye比色仪的可靠性和准确性较比三种比色板无明显差异。结论:Crystaleye比色仪对各品牌的比色板色片的测色结果均有较好的可靠性。对各品牌比色板色片中1/3的测色结果有较好的准确性,具有一定的临床应用价值。     

新型NCC比色板在重新比色中的临床应用研究

目的评价新型NCC比色板在牙科重新比色中的临床效果。方法采用经传统Vita比色板比色失败的168例、208个单位瓷修复体随机分成两组,一组用Vita3D比色板重新比色、配色,重新制作。另一组采用新型SHOFUNCC比色板重新比色、配色,重新制作,比较两组的比色效果。结果NCC比色板组的满意率为92．86％,与对照组相比有显著性差异（P〈0．05）。结论新型NCC比色板颜色较宽,临床比色可取得较好效果。     

The clinical measurement of tooth colour and stain

There are many contributory factors to tooth colour and different techniques for its measurement. The aim of this paper is to evaluate methods of tooth colour and stain measurement, with an emphasis on recent advances in objective clinical measurement techniques. The overall colour effect of natural teeth is created by a combination of light which is reflected and scattered by tooth enamel and the underlying dentine. Developmental defects of the dentition can affect the intrinsic discolouration of teeth, for example, amelogenesis imperfecta and dentinogenesis imperfecta. Extrinsic discolouration is predominantly caused by stain build up on a tooth surface from bacteria, foodstuffs or metalic compounds. Tooth colour and stain measurement are currently assessed using a wide range of measurement methods divided into subjective (visual shade matching) and objective instrumental assessment such as by colourimetry, spectrophotometry and digital image analysis. The most popular method of assessing tooth colour clinically is visual shade matching, as this approach is quick and simple to use. However, variation in results can occur as a consequence of the subjective nature of this method. The instrumental approaches including quantitative light-induced fluorescence remove or significantly reduce the subjective component. Image analysis appears to be the most suitable method for tooth colour measurement and further work is being carried out to establish this approach.     

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.     

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本文着重介绍应用复合树脂对临床不同类型牙体美容缺陷进行美学修复的临床设计方案、洞斜面设计、牙体美学分层修复颜色设计理念与方法,并结合临床病例对修复过程中重要环节如口腔微笑分析、牙体比色、牙体预备、酸蚀、粘接、牙体修复、抛光修整等操作步骤及临床要点进行归纳、总结。旨在为临床医生合理应用复合树脂进行牙体修复,获得良好美学效果提供借鉴和帮助,以期共同努力提高复合树脂牙体美学修复水平。     

A randomised controlled trial to investigate the effects of dehydration on tooth colour

Objectives

To assess effects of dehydration on tooth colour.To investigate any change in tooth colour resulting from dehydration and the time required for any change to return to baseline.

Methods

20 subjects with intact maxillary central incisors were recruited. In each case one incisor was randomly assigned as test tooth with the other acting as control. Spectrophotometric shade of the test teeth was assessed before dehydration and after rubber dam isolation every 10 min for 30 min. Test teeth were allowed to rehydrate and measurements taken every 10 min for 30 min. Data was collected in CIE L*a*b* colour coordinates.A panel of 10 examiners assessed before and after dehydration digital images of the control and test teeth. The panel judged whether central incisors were of same or different shade and which tooth was lighter if a difference was detected.

Results

All colour coordinates showed significant differences between baseline versus 10, 30 min of dehydration and 30 min of rehydration (p < 0.02) except L* after 30 min rehydration. The panel found test and control teeth to be of same shade before and of different shade after dehydration (p < 0.001). Test teeth were significantly lighter after dehydration (p < 0.005).

Conclusion

A significant change in shade of teeth when dehydrated was detected by both instrumental and visual assessment. Teeth became lighter and perceivable colour change had not returned to baseline shade within 30 min of rehydration. Therefore shade matching procedures should be carried out before the teeth are exposed to dehydration.

Clinical significance

As most dental procedures lead to dehydration of teeth which can alter their shade and may lead to errors in shade matching. To avoid unacceptable mismatch of colour between natural teeth and dental restoration it is important that the shade matching procedure is carried out at the beginning of the appointment.     

The effects of polishing and bleaching on the colour of discoloured teeth in vivo

Bleaching is an effective method for restoring the colour of discoloured vital teeth. Power bleaching, in particular, in which a bleaching solution containing 35% hydrogen peroxide is activated by a strong light source using a plasma arc, makes it possible to bleach teeth effectively in a short time. The purpose of this study was to determine how polishing or power bleaching the tooth surface affects tooth colour. The subjects selected were patients who had slightly discoloured teeth. The colour of precisely identified sites on six anterior teeth was measured before treatment, after polishing and after bleaching, to ascertain changes in colour. The measurements revealed that tooth colour changes slightly after polishing, but it shows a much greater change after bleaching, and that the post-bleaching change in tooth colour was caused both by elevation of lightness and reduction of yellowness. They also revealed that the colour difference between pre-treatment and post-bleaching does not depend on the type of tooth. These results suggested that power bleaching is an effective technique for improving slightly discoloured vital teeth, regardless of the type of tooth.     

Colour compatibility between teeth and dental shade guides in Quinquagenarians and Septuagenarians

Summary  The aim of this investigation was to determine colour compatibility between dental shade guides, namely, VITA Classical (VC) and VITA 3D-Master (3D), and human teeth in quinquagenarians and septuagenarians. Tooth colour, described in terms of L * a * b * values of the middle third of facial tooth surface of 1391 teeth, was measured using VITA Easyshade in 195 subjects (48% female). These were compared with the colours ( L * a * b * values) of the shade tabs of VC and 3D. The mean coverage error and the percentage of tooth colours being within a given colour difference (Δ E _ab ) from the tabs of VC and 3D were calculated. For comparison, hypothetical, optimized, population-specific shade guides were additionally calculated based on discrete optimization techniques for optimizing coverage. Mean coverage error was Δ E _ab  = 3·51 for VC and Δ E _ab  = 2·96 for 3D. Coverage of tooth colours by the tabs of VC and 3D within Δ E _ab  = 2 was 23% and 24%, respectively, (Δ E _ab  ≤ 2 as clinically acceptable match). The hypothetical guides performed better and would only need seven to eight tabs to reach the same results as VC and 3D. Both guides had a mean coverage error that was too high and coverage that was too low according to an acceptable colour difference of tooth colour for these subjects. The optimized hypothetical, population-specific guides performed better indicating the possibility for improvement in colour compatibility of the guides with tooth colour in future shade guide development, allowing acceptable shade matching for most of the patients in clinical routine.     

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.     

The bleaching of teeth: a review of the literature

OBJECTIVES: To review current knowledge of tooth whitening with respect to external bleaching methods. DATA: The scope is the external bleaching of vital teeth and focuses on mechanisms; in vivo and in vitro measurement methods, and factors influencing the efficacy of the whitening process. SOURCES: "Medline" and "ISI Web of Science" databases from 1966 and 1974, respectively were searched electronically with key words tooth, teeth, colo*r, white*, bleach* and peroxide. CONCLUSIONS: The importance of tooth whitening for patients and consumers has seen a dramatic increase in the number of products and procedures over recent years, with a concomitant rise in publications on this topic. Literature suggests that the mechanisms of tooth whitening by peroxide occur by the diffusion of peroxide through enamel to cause oxidation and hence lightening of coloured species, particularly within the dentinal regions. A number of approaches are available for measuring changes in tooth colour. These include visual measurements by trained clinicians and instrumental measurements using spectrophotometry, chromameters and digital image analysis. The key factors that affect tooth whitening efficacy by peroxide containing products are concentration and time. In general, higher concentrations are faster than lower concentrations. However, lower concentrations can approach the efficacy of higher concentrations with extended treatment times. Alternative bleach systems to peroxide have received only minor attention. The efficacy of light activated systems versus non-light activated controls in clinical studies is limited and conflicting. Other factors which can influence tooth bleaching outcome include type of stain, initial tooth colour and subject age.     

The prevalence of tooth discolouration and the self-satisfaction with tooth colour in a Chinese urban population

OBJECTIVES: To determine the prevalence of tooth discolouration, self-satisfaction with tooth colour, and correlation with socio-demographic-behavioural factors in adults and teenagers in Chengdu, China. DESIGN: A cross-sectional survey. PARTICIPANTS: 405 Chinese urban adults and teenagers from a multistage random probability sample. METHODS: Tooth colour was measured on the maxillary central incisors using a colorimeter. Tooth discolouration was determined according to the discolouration level figure and evaluation criteria. Self-satisfaction with tooth colour was assessed on a five-point qualitative scale. Data were coded and analyzed using SPSS software. RESULTS: The mean values for L*, a* and b* were 70.67 (s.d. 1.91), 4.29 (s.d. 2.05) and 17.51 (s.d. 4.13), respectively. Age and sex were the most important factors associated with tooth colour (P < 0.05). About half of the study population (48.9%) suffered from some tooth discolouration, and 52.6% were dissatisfied with their tooth colour. Education and smoking were significant factors affecting self-satisfaction with tooth colour (P < 0.05). CONCLUSIONS: Tooth discolouration is common among the Chinese, and many Chinese are dissatisfied with their tooth colour. Self-satisfaction with tooth colour decreased with increasing severity of discolouration. Further research is needed to determine types of tooth discolouration among broader regions in China.