Safety and Effectiveness of a Novel Color Corrector Serum for Causing Temporary Changes to Tooth Shade: A Randomized Controlled Clinical Study.

Tooth color is a major driver of facial esthetics. While permanent changes in tooth shade can be achieved by bleaching and restorations, there is a need for cosmetic products that can cause reversible color changes. This randomized controlled clinical study assessed the effectiveness and safety of a novel color-correcting product (Hismile™ V34 Color Corrector Serum™) versus a placebo (vehicle control lacking the color-change dyes). A single-center, randomized, controlled, examiner-blind, two-group, parallel design, single-use study design was followed. The test products were applied on a cotton bud for 30 s, and then, rinsed off. Tooth shade for maxillary central incisors was measured at baseline, immediately, and at 30 and 60 min, using the Vita Bleachedguide 3D-Master® Shade Guide and the EasyShade Advanced 4.0 spectrophotometer (for determining values of L*a*b*). The subjects (N = 60) had a baseline shade of 1M2 (rank 9) or darker. A single application of the test product resulted in an immediate and significant (p < 0.001) three shade improvement (26.2%) according to the shade guide, and the same significant benefits extended to 30 and 60 min. The placebo product did not alter tooth shade (p = 0.326). These changes were accompanied by significant improvements in the L value (whiteness) up to 30 min, and a reduction in b* (yellowness) for up to 60 min. Two-thirds of subjects using the test product stated in a survey that their teeth appeared both whiter and brighter. No safety issues arose from the use of the test product or vehicle control. These results indicate that using a color corrector can achieve worthwhile changes to tooth shade for up to 60 min.

A Comparative Study to Check the Accuracy of Tooth Shade Selection With Standardized Digital Photographs and a Spectrophotometer.

BACKGROUND: The success of any dental prosthesis depends on aesthetics and function. A proper shade selection is a prime requisite for providing aesthetics to dental patients. PURPOSE: This study aims to compare the photographic method of shade selection with that of a digital spectrophotometer. MATERIALS AND METHODS: The study included 50 participants. The primary inclusion criterion was the presence of the maxillary left central incisor without a history of restorative or endodontic procedures. The shade of the left maxillary central incisor was determined using the VITA Easyshade V spectrophotometer (VITA Zahnfabrik, BadSäckingen, Germany) and the digital photography method for all the selected participants. The CIELAB colour space utilizes three values (L*, a*, and b*) to objectively measure colour. While the digital photography approach used Adobe Photoshop software (Adobe Systems Incorporated, San Jose, CA) to report solely the L*, a*, and b* values, the spectrophotometer reported the L*, a*, and b* values along with the actual shade. After obtaining the values of L*, a*, and b*, ΔE, which is their difference, was calculated using a standard formula. Statistical analysis was carried out by using Student's t-test and proportion z-test. RESULTS: When the comparison of the L*a*b* values was done, Student's t-test showed similar (P>0.05) L(t=0.16, P=0.872), a (t=0.52, P=0.607), and b (t=0.23, P=0.820) values between the two groups; that is, they did not differ significantly or showed perfect matching. There was agreement (ΔE≤2) in 42 (84.0%) cases and disagreement (ΔE>2) in eight (16.0%) cases. The proportion z-test showed an agreement of 84.0%, which was statistically highly significant (z=20.44, P<0.001). CONCLUSION: The true shade of the teeth can be depicted using standardized digital images.

Impact of restoration thickness and tooth shade background on the translucency of zirconia laminate veneers: An in vitro comparative study.

Purpose: Our in vitro comparative study aimed to investigate the impact of thickness and tooth shade background on the translucency of highly translucent zirconia veneers. Materials and Methods: A total of 75 5Y-TZP zirconia veneers of shade A1 were fabricated with thicknesses of 0.50 mm (n = 25), 0.75 mm (n = 25), and 1.0 mm (n = 25). The translucencies were measured on composite resin teeth with shades A1, A2, A3, A3.5, and A4 using a digital color imaging spectrophotometer. Data were analyzed using ANOVA and post hoc Tukey's test (p < 0.05). Results: The translucency values were optimal for the veneers placed over the substrate teeth with shades A1 and A2, regardless of the veneer thickness. Additionally, veneers with a thickness of 0.50 mm exhibited significantly higher translucency than those with thicknesses of 0.75 mm and 1.0 mm. Conclusions: Our study demonstrated that the translucency of the highly translucent zirconia veneers was influenced by both veneer thickness and tooth shade background. The optimal veneer thickness for achieving the highest translucency was 0.50 for the veneers with A1 and A2 shades placed over the substrate teeth. Clinical Relevance: The optimal thickness for achieving the highest translucency of the highly translucent zirconia laminate veneers was 0.50 mm for the veneers with A1 and A2 shades placed over the substrate teeth. Clinicians and dental technicians could consider this when selecting materials for aesthetic restorations.

Gingival Pigmentation Features in Correlation with Tooth and Skin Shades: A Cross-Sectional Study in a Saudi Population.

PURPOSE: The present study aimed to observe the anatomical distribution of gingival melanin pigmentation and evaluate its intensity and extent in different age groups and in correlation with skin and tooth shades. MATERIALS AND METHODS: The participants of this study were 391 patients attending the Dental University Hospital. The presence of gingival pigmentation was assessed using De Krom's Oral Pigmentation Chart and its intensity was assessed using the Dummett-Gupta Oral Pigmentation Index. Skin colour and tooth shade were measured using the Fitzpatrick scale and the VITA classical shade guide, respectively. Statistical analyses included descriptive statistics and Pearson's Χ2 test for the association between the study variables. RESULTS: The prevalence of gingival pigmentation among the sample size was 74.4%, and pigmentations were present on both arches in 57.6% (n = 224) of the participants. The extent (category 1) was highest when pigmentation was evident in both arches, with category 4 being the least extent. Age and sex did not show a correlation with gingival pigmentation. Gingival pigmentation intensity was mild when pigments were present in one arch (p < 0.00), whereas it was heavy when both arches presented with gingival pigmentation. Medium brown colour and tooth shade A1 were the most common among participants with gingival pigmentation (p < 0.00). The association between gingival pigmentation intensity and extent in relation to skin colour was statistically significant (p < 0.00), as was tooth shade (p < 0.05). CONCLUSIONS: Gingival pigmentation is highly prevalent in the Saudi population, with different severity and extent levels. The effect of gingival pigmentation on smile and overall facial aesthetics should be considered when providing dental and cosmetic treatments.

Assessment of Prevalent Gingival Shades in the South Indian Population: An Observational Study.

INTRODUCTION: Gingival shade matching, often overlooked, plays an integral role in designing prostheses for patients with high smile lines, gingival defects, and cases where the acrylic flange of removable dentures extends into the aesthetic zone. The purpose of this study was to find the most prevalent gingival shade in a sample of the South Indian population. MATERIALS AND METHODS:  A total of 110 participants were included in the study based on the inclusion and exclusion criteria. The standard daylight method of shade matching was used for this study. The participants were seated in a dental chair in the vertical position with their heads supported, their mouths open, and cheek retractors in place. The study area, gingiva, and vestibular region in relation to maxillary and mandibular right central incisors were dried with a three-way syringe, 15cm away, for 3 seconds before shade matching for 5 seconds at each reference point with an Ivoclar Vivadent IPS Dsign shade guide. CONCLUSION: The most prevalent shade in the marginal and vestibular regions of the gingiva of the South Indian population was found to be GM2 shade, while the most prevalent shade of the attached gingiva was found to be G2 shade. A good percentage of the attached gingival shade was not matched with the tabs available in this shade guide.

A Smartphone Application for Personalized Tooth Shade Determination.

Tooth shade determination methods for evaluating the effectiveness of whitening products at home are limited. In this study, an iPhone app for personalized tooth shade determination was developed. While capturing dental photographs in selfie mode before and after whitening, the app can maintain consistent illumination and tooth appearance conditions that affect tooth color measurement. An ambient light sensor was used to standardize the illumination conditions. To maintain consistent tooth appearance conditions determined by appropriately opening the mouth, facial landmark detection, an artificial intelligence technique that estimates key face parts and outlines, was used. The effectiveness of the app in ensuring uniform tooth appearance was investigated through color measurements of the upper incisors of seven participants via photographs captured in succession. The coefficients of variation for incisors L*, a*, and b* were less than 0.0256 (95% CI, 0.0173-0.0338), 0.2748 (0.1596-0.3899), and 0.1053 (0.0078-0.2028), respectively. To examine the feasibility of the app for tooth shade determination, gel whitening after pseudo-staining by coffee and grape juice was performed. Consequently, whitening results were evaluated by monitoring the ∆Eab color difference values (1.3 unit minimum). Although tooth shade determination remains a relative quantification method, the proposed method can support evidence-based selection of whitening products.

Evaluation of the Effect of Electronic Cigarette Devices/Vape on the Color of Dental Ceramics: An In Vitro Investigation.

The use of vaping or electronic cigarette devices (ECDs) has recently increased as an alternative to conventional tobacco smoking products. By recording the CIELAB coordinates (L*a*b*) and computing the total color difference (ΔE) values using a spectrophotometer, the effect of ECDs on contemporary aesthetic dental ceramics was investigated in this in-vitro study. A total of seventy-five (N = 75) specimens from five different (n = 15) dental ceramic materials (Pressable ceramics (PEmax); Pressed and layered ceramics (LEmax); Layered zirconia (LZr); Monolithic zirconia (MZr) and Porcelain fused to metal (PFM)) were prepared and exposed to aerosols produced by the ECDs. The color assessment was performed using a spectrophotometer at six time intervals (0 = baseline; 250-puff exposures; 500-puff exposures; 750-puff exposures; 1000-puff exposures; 1250-puff exposures; and 1500-puff exposures). By recording L*a*b* and computing total color difference (ΔE) values, the data were processed. A one-way ANOVA and Tukey procedure for pairwise comparisons were used to assess color differences between tested ceramics (p < 0.05). All test materials demonstrated significant color differences (ΔE) after exposure to vaping (p < 0.05). The LZr group displayed noticeably high ΔE values at all the distinct puff exposure intervals, with the highest ΔE value of (13.67) after 1500 puffs. The lowest (ΔE) values were observed in the PFM group after 250 and 500 puffs (0.85 and 0.97, respectively). With the exception of the group PEmax (p = 0.999), all groups produced readings of "ΔE" that indicated significant differences (p < 0.05) at various degrees of puff exposures. ECDs can noticeably alter the color of the dental ceramics affecting the esthetics of the patients. All the materials tested demonstrated significant color changes (ΔE > 3.33) above the clinically acceptable threshold, except for the PFM and PEmax group (ΔE < 3.33) which showed color stability after exposure to the ECDs.

Tooth Shade and Blood Type: A Descriptive Cross-sectional Study in Tunisia.

AIM: The aim of the study was to assess the prevalence of tooth shade and its correlation with blood type. MATERIALS AND METHODS: This study analyzed 312 blood donors at the university Hospital in Monastir between November 2021 and June 2022. Both male and female subjects were included, with ages ranging from 18 to 60 years old. Patients with certain dental conditions or habits were excluded from the study. The study recorded various information about blood donors, including gender, age, governorate of origin, tooth shade, and blood type. The tooth shade values were recorded using A-D shade guide. Data input and tabulation were carried out using Microsoft Excel 2016 and SPSS (version 25.0). RESULTS: The study included 312 participants, with 85.58% males and 14.42% females. Tooth shade value B was the most prevalent (43%), and D was the least prevalent (7%). The statistical analysis showed that there was no significant link between tooth shade and blood type. However, there were three statistically significant categories: Blood type B/Tooth shade B, Blood type O/Tooth shade C, and Blood Type O/Tooth shade D. CONCLUSION: The study examined the link between tooth color and blood type but did not find a significant link. However, significant values were found in different subgroups. A wider selection of subjects and a more rigorous measurement equipment might lead to more favorable results. CLINICAL SIGNIFICANCE: By considering the patient's blood type alongside other relevant factors, clinicians can enhance the accuracy and precision of tooth shade selection, resulting in harmonious and natural-looking dental restorations. This approach improves patient satisfaction and acceptance.

Comparison of Shade Matching Ability among Dental Students under Different Lighting Conditions: A Cross-Sectional Study.

Successful esthetic dentistry to meet patient satisfaction and produce a progressive impact on someone's personality cannot be succeeded without proper shade selection, both for direct or indirect restoration of dentition. The accurate shade selection is one of the most interesting phases of restoring the natural look of teeth. In clinical practices, dental students should be aware of the various light sources used for shade selection. The purpose of this research is to compare the shade matching ability of clinical and non-clinical students under clinical and correcting light. This comparative cross-sectional study was instigated amongst clinical and non-clinical students of the dental complex of King Faisal University, Kingdom of Saudi Arabia, after obtaining ethical approval from the Research Ethics Committee with reference number (KFU-REC-2022-MAR-EA000518). A total of 102 students assessed the shade under clinical (fluorescent light) and correcting light (handheld Dental Base Light) by using VITA Classical shade guides. Statistical analysis was done using SPSS version 23 (Armonk, NY, USA). The Chi-square test and t-test were used to evaluate the association between shade matching scores under correcting and clinical light. Out of 102 students, 41 (40.2%) were non-clinical and 61 (59.8%) were clinical, with a mean age of 21.66 ± 1.397 years. Shade matching scores were found significantly higher (p < 0.001) with the light-correcting device (2.29 ± 1.26) as compared to clinical light (1 ± 1.11) for non-clinical students. Similarly, clinical students also had significantly better (p < 0.001) shade matching with the light-correcting device (4.01 ± 1.34) in comparison to clinical light (2.47 ± 1.25). This study concluded that the shade matching scores under correcting light was significantly better than the results obtained by dental operatory light. Furthermore, it was also evidenced that clinical students' skills in matching shades were significantly improved under a correcting light source as compared to non-clinical students.

Investigation of the esthetic perception of different canine parameters.

OBJECTIVES: The aim of this study is to analyze the esthetic perception of selected canine features, namely crown length, shade, inclination, and angle of incisal edge tip. MATERIALS AND METHODS: The anterior maxillary teeth of a Central European woman were photographed and digitally modified in order to investigate esthetic perceptions of the above four categories. Three groups of examiners with different levels of experience in the field of dentistry (laypersons/inexperienced dental students, advanced dental students, dentists) evaluated the photographs twice with the help of visual analogue scales. RESULTS: The best-evaluated canines have approximately the same length as the central incisor, have the same shade as the other anterior teeth, are best embedded in a lighter overall tooth shade, are neutral to slightly palatal inclined, and have a right angled to rounded incisal edge (≥ 90°). The canines evaluated as least esthetic, however, are longer than the central incisors, darker, inclined labially, and have a tapered incisal edge. No significant differences could be found between the evaluations of the groups with regard to the four feature categories. CONCLUSIONS: Laypersons, advanced dental students, and dentists generally evaluate according to the same esthetic standards. Gender does not have a significant influence on evaluation. Clear definitions of esthetically favored shades, incisal edge shapes, inclination, and lengths of the canines can be given. CLINICAL RELEVANCE: Since the esthetics of the smile line play a critical role for patients, dentists, dental technicians, and their supplying industry, knowledge of the esthetically preferred morphology of canines is essential. CLINICAL SIGNIFICANCE: The aim of this study is to give clear definitions of esthetically favored shades, incisal edge shapes, and lengths of the canines, as the esthetics of the smile line play a critical role for patients, dentists, dental technicians, and their supplying industry (e.g., denture tooth manufacturers). Precise knowledge of esthetic preferences is important in clinical practice for both dentists and dental technicians, for example, in order to adequately advise patients regarding esthetic corrections. Also, in the case of missing teeth, this knowledge is essential for optimal and satisfactory restorations. Thus, this study can contribute to the satisfaction of general practitioners and patients.

Are there any color match and color correlation between maxillary anterior teeth?

OBJECTIVE: To evaluate the color match and color correlation between maxillary anterior teeth. MATERIALS AND METHODS: CIELab values of 1182 intact maxillary anterior teeth in 197 human specimens were measured through spectrophotometry. ∆E00 color differences between similar regions of the same and different type teeth were calculated and compared with perceptibility and acceptability thresholds using 1-sample t test to evaluate color matches. Regression analyses assessed linear relationships between the color coordinates of similar regions of different type teeth. Percentages of different modes of the color match between the same specimen's teeth (2-tooth/3-tooth color match or color mismatch) were determined. RESULTS: Mean ∆E00 values for the same type teeth were less than 1.8 (p = 1). Mean ∆E00 values for different type teeth were mostly greater than 1.8 (p < 0.001), except for central and lateral teeth in middle (p = 0.29) and incisal (p = 0.75) regions and for lateral and canine teeth in cervical regions (p = 0.33). The 2-tooth color match showed the highest percentage (>50%). CONCLUSIONS: The same type teeth indicated color matches. Central and lateral teeth showed color matches in middle and incisal regions, while lateral and canine teeth disclosed color matches in cervical regions. The corresponding color coordinates of mismatched regions were linearly correlated. CLINICAL SIGNIFICANCE: In order to predict and determine the shade of maxillary anterior teeth and create natural colors for corresponding restorations, some tooth color relationships and equations are presented in this study.

Does age determine the lightness and darkness of tooth shades? A retrospective study.

The study aimed to analyze whether age determines the lightness and darkness of tooth shades. The demand for esthetics has soared to a next level progressively in many developing countries including India; the importance provided to match the tooth shade creates a great difference in the satisfactory outcome of the patient in the field of dentistry. Therefore, this particular study analyzed the differences in tooth shade values based on age factor among the Indian population. 238 individual's case sheets with the age between 18 and 65 years. 18-30 years of age were considered as group 1 (young adults), 31-45 years in group 2 (middle age), and above 45 years in group 3 (older age). The clinical intraoral pictures of the patients which were taken prior to the treatment were obtained and the shade of any one of the upper permanent central incisors was assessed using the Vitapan 3D-Master shade guide, especially the middle portion of the facial surface of the incisors. The collected data were imported to Statistical Package for the Social Sciences, version 17 (IBM Corporation). Chi-square test was used to assess the significance. From the data, 17.2% showed A1 shade, 35.2% A2 shade, 7.5% A3 shade, 5% A4 shade, 7.1% B1 shade, 15.9% B2 shade, 7.1% B3 shade, 3.3% B4 shade, and 1.1% C1 shade. The individuals under the category of above 45 years showed darker tooth shade compared to young adults and middle age population (Chi-square test, P < 0.001). Significant association was established with darker tooth shades by increasing age and vice versa. The older age population showed a higher correlation for dark shade between teeth. The aging process significantly affects the teeth color. Hence, as a dentist, it is important to know about the distribution of tooth shade and its association with age to get an outcome with adequate patient satisfaction.

Visual and digital tooth shade selection methods, related effective factors and conditions, and their accuracy and precision: A literature review.

OBJECTIVE: Despite developments of dental shade selection methods, shade selection is still a challenge affecting esthetic outcomes. The purpose of this review was to discuss visual and digital shade taking methods, related effective factors and conditions, and their accuracy and precision to find out the most accurate, precise shade selection method available in dentistry. OVERVIEW: The key terms of accuracy, background, ceramic, color, colorimeter, color analysis, color science, color measurement, color measuring instrument, color matching, composite resin, dental/tooth shade guide, digital camera, esthetics, imaging, imaging application/program/ software, intraoral scanner, light source, photography, precision, shade, shade matching/ determination/prediction/reproduction/selection, shade taking device, spectrophotometer, spectrophotometry, tooth color measurement, tooth color/shade, and visual perception were used separately and jointly to detect related English-language articles published between January 1, 1985, and January 1, 2021. Electronic/non-electronic searches of Google Scholar/PubMed/Scopus/Web of Science were accomplished. Consequently, 249 articles were considered. Accordingly, the digital methods show higher accuracy and precision compared to the visual methods while requiring to be enhanced regarding accuracy to achieve ideal shade taking results. CONCLUSIONS: Dental spectrophotometers provide the highest overall accuracy and precision among different shade selection methods while needing clinical setting to control related effective factors/conditions and technological improvement to perform optimally. CLINICAL SIGNIFICANCE: Different factors can affect the accuracy and precision of tooth shade selection methods and devices. The understanding of these effective factors may lead to a standard shade taking protocol using accurate, precise methods and devices.

Impacts of the Triple bristles three-sided sonic powered toothbrush on tooth shade, plaque control and gingival health.

OBJECTIVES: To evaluate the efficacy of the Triple bristles three-sided sonic powered toothbrush in plaque removal and its impact on tooth shade and gingival health, and to compare this with a conventional manual toothbrush. METHODS: Fifty two participants (26 males and 26 females; mean age [SD] = 22.48 [1.52], SE = 0.210, 95% CI = 22.06-22.90) were recruited into this controlled within-subject, randomized, two-treatment, 1-month crossover and examiner-blinded observational study between October 2020 and January 2021 in the School of Dentistry, University of Jordan. Within each participant, the upper and lower jaws were randomized to receive a brushing protocol either with the Triple bristles three-sided sonic brush or with a soft manual standard toothbrush with flat trimmed bristles. Tooth shades were recorded for upper and lower anterior and premolar teeth. The Turesky-Modified Quigley-Hein Plaque Index (TMQHPI) and bleeding on probing (BOP) were evaluated at study baseline, 1 week and 1 month after applying the brushing protocol. RESULTS: Both tested brushes were associated with significant reduction in plaque scores and BOP (p < 0.05). The Triple bristles brush was more effective in reduction in plaque and BOP in the lower jaw and among females than the manual brush (p < 0.05). CONCLUSIONS: The Triple bristles brush was more superior for reduction in plaque and probing on bleeding in the lower jaw and among females.

Tooth Shade and Skin Colour: A Descriptive Cross-Sectional Study.

INTRODUCTION: Selection of proper tooth shade is one of the most significant factors influencing patients' aesthetic perception and improved prosthesis acceptance. Guidelines in the dental literature suggest age, sex, colour of skin, hair and eye for selecting tooth shade when past records cannot be obtained. The objective of the study was to find out the prevalence of the most common tooth shade in relation to the skin colour and the prevalence of the same in relation to age and sex. METHODS: A descriptive cross-sectional study was carried out at Kathmandu Medical College from June to August 2019. Vitapan Classical Shade guide was used to select the shade of upper right central incisor in 338 participants. Revlon Foundation Makeup Shade guide was used to determine colour of skin. Participants were examined without facial makeup. Skin colour and teeth shade were examined in daylight at about the same time of the day. Data obtained were computed and analysed using Microsoft Excel 2016 software. RESULTS: Prevalence of tooth shade with high value (lighter shade) was seen in all fair 121 (35.8%), medium 63 (18.6%) and dark skin tones 23 (6.8%). Most common teeth shade in fair individuals was B1 47 (37.9%), in medium also B1 25 (7.4%) and dark was B2 9 (2.7%). Age range of 10 to 35 years had tooth shade with higher value 159 (47.04%). CONCLUSIONS: Hence, teeth shade with high value (lighter shade) was prevalent in skin tone of all types in current study. Skin tone was not related to teeth shade selection, teeth became darker with age and females had lighter teeth shade (high value).

How reliable and accurate is the shade determination of premolars by spectrophotometry?

OBJECTIVES: To evaluate the reliability and accuracy of spectrophotometric shade determination of premolars and to compare the results with those for incisors. MATERIAL AND METHODS: Fifty-seven participants with natural maxillary incisors and premolars were recruited to investigate the research question. The colour of test teeth (incisors, n = 210; premolars, n = 192) was measured by use of the Vita Easyshade Advance (ES-A) and Vita Easyshade V (ES-V). Accuracy was evaluated by rating the shade tab matches recommended by the devices (scale, 1 = excellent match to 3 = mismatch). Inter-device reliability between the ES-A and ES-V for measurement of incisors and premolars was evaluated using intra-class correlation coefficients (ICC). The ratings for the accuracy of the devices were analysed using descriptive and bivariate statistics. A linear regression model was used to evaluate possible independent influencing confounders on the shade match. RESULTS: Inter-device agreement of the ES-A and ES-V for measurement of incisors and premolars was excellent for all colour components (ICC > 0.9). The accuracy of both devices was acceptable to excellent for incisors and premolars, although the ES-V was more accurate than the ES-A (p < 0.001). No significant difference in accuracy was detected between premolars and incisors (p = 0.182). The linear regression model confirmed the bivariate testing. CONCLUSIONS: The reliability and accuracy of spectrophotometric shade determination seem comparable for incisors and premolars. The recently introduced ES-V seems more accurate than its predecessor model. Further studies are needed to validate the results of this study.

Use of a new skin colour measurement method for the investigation of relationship between skin and tooth colour.

PURPOSE: There is conflicting information about the relationship between tooth color and skin color in the literature. The aim of the present study was evaluation of the correlation between L, a, b values of skin and tooth shade using a new skin color measurement method. MATERIALS AND METHODS: CIELab values of teeth were obtained through measurements from the middle third of the labial surfaces on central incisors of individuals using a clinical spectrophotometer. CIELab values of the skin were measured through facial images using a software which was manufactured for present study. A statistical analysis program (SAS 9.4) was used for the analysis of the data. Kolmogorov-Smirnow test, t-test, and multivariate regression analysis were used to evaluate the data (α=0.05). RESULTS: Correlations between variables revealed that while the lowest and statistically insignificant correlations were observed with a* values of the skin, significant correlations did not exceed moderate level (p < .05). When considering regression analysis results, b* values of the skin had a statistically significant effect in describing b* values of the tooth, while L* and a* values of the skin were observed to be insufficient in describing L* and a* values of the teeth. CONCLUSION: Results of this study suggest that different significant correlations were observed between the skin and tooth color for different L*, a*, and b parameters (p <0.05 and p <0.01). The results indicated that skin color can be used for tooth color selection in case of loss of natural teeth or when discoloration is present on existing teeth.

Effect of application of desensitizers before bleaching on change of tooth shade.

The aim of this in vitro study was to evaluate the effects of desensitizer pre-treatment on in-office bleaching using an artificial discoloration tooth model. The stained specimens were divided into four groups (n=10); without application (Control group), Shield Force plus (SF group), UltraEz (UE group) and Teeth Mate AP paste (TM group) applied before bleaching. Each group was bleached by an in-office bleaching agent. The CIE L*a*b* values were measured by a colorimeter before and after ten consecutive bleaching treatments and the color difference (∆E) was calculated. There was no statistical difference among ∆E values of Control, UE, and TM groups (p>0.05). There was a significant difference between SF and Control groups (p<0.001). It was concluded that application of TM and UE did not affect the change of tooth shade while SF application impeded the bleaching effect.

The Effect of Accelerated Aging on the Colour Stability of Composite Resin Luting Cements using Different Bonding Techniques.

INTRODUCTION: The main criterion of successful aesthetic restoration is to match the colour of the adjacent teeth. Porcelain laminate veneer is widely practiced indirect restoration in the contemporary aesthetic dentistry. The underlying luting cement colour influences the final outcome of the thin, translucent veneer shade. Hence, colour stability of luting cement is important criteria during their selection. AIM: The objective of the study was to assess the colour stability of the different dentin bonding techniques in composite resin luting cements. MATERIALS AND METHODS: A total of forty intact, non carious teeth were prepared to receive Porcelain Laminate Veneers (PLV). The lithium disilicate PLV were fabricated, and fitting surface was conditioned with 5% hydrofluoric acid and silane application. According to the bonding technique employed for the cementation of the PLV, the teeth samples were randomly divided into the four groups of ten each. The Group I and Group II samples were conditioned with etch and wash; the polymerization of resin was accomplished with the dual cure for Group I and light cure for Group II. The Group III and Group IV samples were conditioned with self-etch and self-adhesive technique correspondingly. The teeth shade was recorded in similar locations with a spectrophotometer before and after subjecting them to the accelerated ageing process. The ageing process included the thermocycling process in water between 5°C and 55°C for 5000 cycles followed by 100 hours xenon light exposure. The data were analysed with SPSS 19.0 by ANOVA and LSD post-hoc comparison. RESULTS: The higher mean colour change was observed in Group I sample (etch washdual cure) with a ∆E value of 2.491. The ∆E value for Group II (etch wash-light cure) and Group III (selfetch) was 1.110 and 2.357 respectively. The lowest mean colour change was observed in Group IV (self-adhesive) with ∆E at 0.614. Statistical analysis showed significant differences between Group IV and Group I; Group IV and Group III with p<0.05. CONCLUSION: The self-adhesive and etch-wash light cure luting cements were found to be less susceptible for colour changes due to accelerated ageing.

Effects of combining ozone and hydrogren peroxide on tooth bleaching: A clinical study.

OBJECTIVES: The purpose of this study was to evaluate the efficiency of bleaching after combining ozone and 38% H2O2 in comparison to the sole use of 38% H2O2. METHODS: Consecutive 26 participants (13 males and 13 females) were recruited into this study. They were randomly allocated into 2 groups (n=13 for each group). In group 1 (test group); the participants' upper anterior teeth were treated with 38% H2O2 for 20min then the teeth were exposed to ozone for 60s (healOzone(®) X4, KaVo Dental, Biberach, Germany). In group 2 (controls); the upper anterior teeth were treated with 20min of 38% H2O2 only. The shade of teeth was evaluated by recording the L* a* b* values and Vita Classic shades at study baseline and after bleaching in both groups. The statistically significant changes were set at P≤0.05. RESULTS: Tooth sensitivity and teeth shades were comparable between groups at study baseline (p>0.05). Controls reported more tooth sensitivity following bleaching (p<0.001). Teeth achieved better Vita shades, higher L* values (lighter shades), and lower a* and b* values (lighter shades) after bleaching in both groups (P≤0.05). However, teeth bleached with H2O2 and ozone achieved better Vita shades, higher L* values and lower a* values (lighter shades) than those bleached with H2O2 alone (p<0.001). Changes in b* values were not significantly different between groups. CONCLUSIONS: Bleaching with 38% H2O2 for 20min followed by 60s of ozone application would result in teeth with lighter shades than bleaching with 38% H2O2 alone.