In vitro comparison of visual and computer-aided pre- and post-tooth shade determination using various home bleaching procedures

Accuracy of Color Determination by Intraoral Scanners in Bleached and Unbleached Teeth: A Clinical Study

PURPOSE

This clinical study aimed to evaluate the color measurement ability of intraoral scanners (Trios 3, (3Shape, Copenhagen, Denmark) and Cerec Omnicam, (Dentsply Sirona, Charlotte, NC, USA) in comparison to VITA Classical and VITA 3D-Master shades obtained by a spectrophotometer (Easyshade V, VITA, Zahnfabrik, Bad Säckingen, Germany).

METHODS

Four hundred eighty teeth from thirty patients were included in the study. Fifteen patients had never undergone bleaching, and the other fifteen had undergone professional bleaching within the last 6 months. VITA Classical and VITA 3D Master shades were determined using Trios 3 (T3), Cerec Omnicam (CO), and EasyShade V from cervical, middle, and incisal/occlusal areas of maxillary and mandibular central and lateral incisors, canines, and first premolars. Color accuracy rates (cAR) were assessed by categorizing the color data according to the Munsell color system for bleached and unbleached teeth, maxillary and mandibular, and teeth arranged from anterior to posterior in each quadrant. McNemar, Mann-Whitney U, and Wilcoxon tests and Point Biserial Correlation Analysis were used for statistical analysis (significance level α=0.050).

RESULTS

The bleached teeth had a significantly higher cAR for T3 in VITA 3D Master and VITA Classical guides (p<0.05). The cAR of the incisal area in VITA 3D Master was significantly lower in both scanners (p<0.05) except for the lightness/hue/chroma of bleached teeth. T3 cAR increased statistically significantly from anterior to posterior (p<0.001); however, no significant difference was found for CO (p=0.482).

CONCLUSION

The color accuracy rates of both scanners for shade guides that included all color components in this study were below 30%, which was not clinically satisfactory for color measurement. Confirming the measurements with a spectrophotometer is recommended.

Over-the-counter products in tooth bleaching: A scoping review

OBJECTIVE

To map and summarize the current scientific evidence concerning the active ingredients, effectiveness, and adverse effects of over-the-counter (OTC) bleaching products.

DATA AND SOURCE

This study was conducted according to the PRISMA-ScR guidelines for scoping reviews and registered on the Open Science Framework platform.

STUDY SELECTION

Database searches were conducted in PubMed/MEDLINE, Embase, and Scopus up to January 2024. All in vitro, in situ, and clinical studies evaluating the effectiveness and adverse effects of OTC bleaching products were included. A descriptive analysis of the included studies was performed.

RESULTS

A total of 88 studies were included. Most of them were in vitro studies (n = 49), followed by randomized clinical trials (n = 28). The main OTC bleaching products identified were whitening or stain-removing toothpastes (n = 42), followed by whitening strips (n = 39). Most clinical studies indicate that whitening strips are effective in improving tooth color and providing whitening benefits. In contrast, the bleaching effectiveness of toothpastes, mouth rinses and whitening trays was mainly supported by in vitro studies. The main adverse effects associated with OTC bleaching agents were tooth sensitivity and gingival irritation.

CONCLUSION

A wide variety of OTC bleaching products is available for consumer self-administered use. Clinical studies have mainly confirmed the bleaching effectiveness of whitening strips, while the validation for toothpastes, mouth rinses and whitening trays has mainly relied on in vitro studies. Nevertheless, the use of OTC bleaching products may result in adverse effects, including tooth sensitivity, gingival irritation, and enamel surface changes.

CLINICAL SIGNIFICANCE

Some over-the-counter bleaching products may have whitening properties supported by clinical studies, particularly those containing hydrogen or carbamide peroxide. Nonetheless, clinicians must be aware of the potential risks associated with excessive self-administration of these products, which may result in adverse effects.

Preemptive use of ibuprofen and desensitizer decreases immediate tooth sensitivity after in-office bleaching: A triple-blind, randomized, placebo-controlled clinical trial

BACKGROUND

The authors evaluated the synergistic analgesic effect of preemptive administration of 400 mg of ibuprofen (IBU) and potassium fluoride 2% (KF2), both in isolation or combination, on the painful perception of tooth sensitivity after tooth bleaching.

METHODS

Fifteen patients participated in this triple-blind, randomized, placebo-controlled clinical trial. The study used a crossover design for drug administration and a split-mouth design for desensitizer agent. Four paired groups were formed: IBU plus KF2 (IBU + KF2); IBU (IBU + placebo KF); KF2 (placebo IBU + KF2), and placebo (placebo IBU + placebo KF). The outcome measure was the perception of tooth sensitivity, assessed using a visual analog scale. Data were collected at 4 different times: immediately after tooth bleaching (baseline) and after 6, 30, and 54 hours. Statistical analysis was performed using the Friedman test and relative risk.

RESULTS

IBU plus KF2 was found to be more effective in reducing tooth sensitivity immediately after bleaching (baseline) compared with the placebo group (P < .05). The risk of experiencing moderate or severe tooth sensitivity was approximately 4 times higher in the placebo group than in the IBU plus KF2 group (relative risk, 4.00; 95% CI, 1.01 to 15.81; P = .025).

CONCLUSIONS

The combined use of 400 mg of IBU and KF2 appears to be beneficial in managing postbleaching tooth sensitivity. It provides a superior analgesic effect compared with placebo.

PRACTICAL IMPLICATIONS

The preemptive administration of IBU plus KF2 reduces tooth sensitivity after tooth whitening when compared with placebo. This clinical trial was registered in the Brazilian Clinical Trials Registry Platform. The registration number is U1111-1249-8191.

In vitro evaluation of the effect of addition of biomaterials to carbamide peroxide on the bleaching efficacy and microhardness of enamel

Background and Aim

Teeth bleaching, although considered safe and conservative, cause microscopic changes in the tooth structure. The aim of this study is to evaluate the bleaching efficacy of carbamide peroxide (CP) bleaching gel when modified with the incorporation of bioactive glass (BG) and hydroxyapatite (HA) and its effect on enamel microhardness.

Materials and Methods

Forty-five maxillary incisors were decoronated, artificially stained and mounted in acrylic. The samples were divided into three groups of 15 each and subjected to the following bleaching protocol for 8 h/day at 37°C for 2 weeks: Group 1 - 16% CP, Group 2 - CP modified with BG, and Group 3 - CP modified with hydroxyapatite (HA). Spectrophotometric color assessment using CIE L*a*b* system and Vickers microhardness were assessed before and after bleaching. Data were analyzed using Student's paired t-test and one-way ANOVA followed by Tukey's post hoc analysis.

Results

There was a significant change in color (L*a*b*) in all the three groups when compared to the baseline values. However, no significant difference in the total color change (ΔE) was observed between the three groups. Enamel microhardness reduced significantly in the CP group, whereas it increased in the BG and HA group after bleaching. Scanning electron microscopy images of BG and HA groups showed crystalline deposits suggesting mineral deposition.

Conclusion

Addition of biomaterials can be a beneficial alternative to bleaching with CP alone, considering the increase in microhardness without hindering the bleaching action.

Comparison of different digital shade selection methodologies in terms of accuracy

PURPOSE

This study aims to evaluate the accuracy of different shade selection techniques and determine the matching success of crown restorations fabricated using digital shade selection techniques.

MATERIALS AND METHODS

Teeth numbers 11 and 21 were prepared on a typodont model. For the #11 tooth, six different crowns were fabricated with randomly selected colors and set as the target crowns. The following four test groups were established: Group C, where the visual shade selection was performed using the Vita 3D Master Shade Guide and the group served as the control; Group Ph, where the shade selection was performed under the guidance of dental photography; Group S, where the shade selection was performed by measuring the target tooth color using a spectrophotometer; and Group I, where the shade selection was performed by scanning the test specimens and target crowns using an intraoral scanner. Based on the test groups, 24 crowns were fabricated using different shade selection techniques. The ΔE values were calculated according to the CIEDE2000 (2:1:1) formula. The collected data were analyzed by means of a one-way analysis of variance.

RESULTS

For the four test groups (Groups C, Ph, S, and I), the following mean ΔE values were obtained: 2.74, 3.62, 2.13, and 3.5, respectively. No significant differences were found among the test groups.

CONCLUSION

Although there was no statistically significant difference among the shade selection techniques, Group S had relatively lower ΔE values. Moreover, according to the test results, the spectrophotometer shade selection technique may provide more successful clinical results.

In vitro evaluation of the effect of different bleaching varnishes: Hydrogen peroxide penetration into the pulp chamber and color change

OBJECTIVE

To evaluate the penetration of hydrogen peroxide (HP) into the pulp chamber and the color change of different bleaching varnishes in low concentrations used for at-home bleaching.

MATERIALS AND METHODS

Ninety healthy premolars were used, randomly distributed into nine groups (n = 10) according to bleaching varnish (PL, PolaLuminate; VS, VivaStyle Paint On Plus; CA, Cavex Bite&White whitening pen and; AW AlignerWhite) and time (10 and 30 min), and a control group (no bleaching). The penetration of HP was evaluated by UV-Vis spectroscopy. To evaluate the color change (ΔEab , ΔE00 , ΔWID ) a digital spectrophotometer was used (α = 0.05).

RESULTS

The AW group in 10 min and the control group showed similar and lower HP penetration in the pulp chamber when compared to the other groups (p = 0.003). Increasing the application time to 30 minutes elevated the amount of HP inside the pulp chamber for all groups (p = 0.003), except for PL (p > 0.05). When applied for 30 min all bleaching varnishes showed higher color change (ΔWID ) when compared to 10 min (p = 0.04).

CONCLUSIONS

For all bleaching varnishes evaluated, PolaLuminate applied for 30 min showed lower penetration into the pulp chamber and higher bleaching effects.

CLINICAL SIGNIFICANCE

The use of bleaching varnishes seems promising for teeth bleaching, but it varies according to user product and protocol.

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.

The Effect of In-Office Bleaching with Different Concentrations of Hydrogen Peroxide on Enamel Color, Roughness, and Color Stability

The aim of this study is to evaluate the effectiveness of in-office bleaching in esthetic dentistry on the roughness and color stability of the enamel surface, using different concentrations of hydrogen peroxide (HP). Fifty human incisors were randomly divided into 5 groups (n = 10). No bleaching was performed in the control group. For these groups, concentrations of 40% HP with fluoride (F), 35% HP with calcium (Ca), 25% HP with nano-hydroxyapatite (nHA) and 18% HP with nHA were used for bleaching in the test groups. Surface roughness was assessed at baseline after bleaching occurred. Color measurements were first obtained at baseline, then after the first and second sessions of bleaching, and, finally, after the staining protocol. Scanning electron microscopy and atomic force microscopy were performed. Statistical analysis was conducted with a one-way ANOVA, followed by a post hoc Tukey's test and a paired-samples t-test (p < 0.05). All the bleaching gels used exhibited a similar color change (p > 0.05). Bleaching gels containing 18% HP with nHA and that containing 35% HP with Ca caused less surface roughness of the enamel. Of these concentrations, 25% HP with nHA caused the most surface roughness and no significant difference was observed, compared with 40% HP with F. The highest coloration after bleaching was observed in 40% HP with F and 25% HP with nHA. The lowest coloration was obtained in 35% HP with Ca and 18% HP with nHA but no significant difference was observed between them and the control group. A concentration above 18% HP does not increase the bleaching effectiveness. The results show that 18% HP with nHA and 35% HP with Ca resulted in the least increase in enamel surface roughness when compared to high-concentrate HP; however, it also prevented recoloration after bleaching.

Evaluation of the effect of anodization-colored titanium abutments and zirconia substructure thickness on zirconia substructure color: An In vitro study

BACKGROUND AND AIM

The aim of this study is to evaluate the effect of anodized titanium abutments and zirconia substructure thickness on the color of zirconia substructure.

MATERIALS AND METHODS

In this study, an electrochemical anodization setup was prepared for titanium coloring. Commercial titanium, anodization-colored yellow and pink titanium, and zirconia were used as different abutment specimens. Thirty zirconia discs in 0.7, 0.9, and 1.1 mm thickness were prepared from zirconia blocks as zirconia substructure specimens (n = 10). Zirconia substructure specimens of different thicknesses were placed on abutment specimens of different colors and L*, a*, b* values were measured with a spectrophotometer device. Color difference (ΔE) was calculated according to the CIELab formula by comparing the L*, a*, and b* values obtained on the zirconia abutment with the L*, a*, and b* values obtained on the other abutments. Statistical analyzes were performed with two-way analysis of variance and Tukey Honestly Significant Difference (HSD)test (p < 0.05).

RESULTS

The increase in the thickness of the substructure resulted in a statistically significant difference on ΔE, L*, a*, and b* values (p < 0.001). The effect of abutment color had no significant effect on ΔE values. The highest ΔE value was 18.10 at zirconia substructure with 0.7 mm thickness when paired with pink-anodized titanium abutment specimens.

CONCLUSION

The thickness of zirconia substructure and the color of titanium abutments affect zirconia substructure color.

Whitening Optical Effect of New Chewing Gums

Background:

Today, many treatments are available to enhance the color of teeth, but they require a few days to weeks to deliver this effect.

Objective:

To evaluate the instantaneous optical whitening effect of two new sugar-free chewing gums and one dentifrice of proven efficacy versus one placebo chewing gum.

Methods:

This was a single-blind, parallel trial. 424 participants entered the study and were randomly allocated to four groups. They received a personal silicone mask with a calibrated hole at one upper incisor to apply a dental colorimeter. The tools tested were chewing-gum containing indigotine (E132-FD&C Blue 2) and spirulina, chewing-gum containing only spirulina, chewing-gum placebo, and dentifrice containing Blue Covarine. Vita® Easyshade scored the tooth color, and the WIO and WID whiteness indexes were calculated. For chewing gums, the color of the teeth was scored before the assumption and after 2’30” of mastication. For dentifrice, participants brushed for 1’30”, then rinsed, and the color was scored before brushing and after 2’30”. Statistical analysis was performed by ANOVA and Tukey post-hoc.

Results:

The two experimental whitening chewing gums and the dentifrice significantly increased the WIO and the WID indexes from the baselines (p<0.001). Moreover, their effects were statistically greater than those reported for the placebo chewing gum (p<0.05) but not significatively different among them (p=NS).

Conclusion:

All the tested whitening tools showed an instant optical whitening perception. Further studies are required to assess the intensity of the effect over a prolonged time to meet the people's request for fast whitening tools.

The clinical trial registration no. is PVM-2020-01.

Tooth color in dental students from Buenos Aires University, Dental School, Argentina

The aim of this study was to evaluate tooth color in dental students at the University of Buenos Aires, Argentina. The participants were 184 students (157 women and 27 men) aged 21 to 33 years, mean age 24.45 (SD 2.79) years, who were in the fourth year of their dental degree. They agreed to participate through an informed consent. Exclusion criteria were: having undergone a bleaching treatment within the previous six months, presence of total or partial peripheral restoration, pigmentations, fracture, carious and non-carious lesions or absence of the right upper central incisor (1.1). A dental prophylaxis procedure was performed on the buccal surface of each 1.1 tooth with a prophylaxis brush (TDV) mounted on a low-speed rotary instrument Kavo 2068 CHC (Germany) micromotor and a Kavo LUX K201(Germany) contra-angle. Shade was measured in the middle third of each 1.1 tooth, by the same observer, using a VITA Easyshade V spectrophotometer (Zahnfabrikn Bad Säckingen, Germany), which was calibrated before each determination according to manufacturer's instructions, in the same dental unit (Sino S2316), with natural illumination, in the same time slot, without using the dental unit lamp. The results were recorded in an ad-hoc form and rates and confidence interval were obtained. Shade prevalence percentages (95% CI) were: A1: 46.2 (38.83 - 53.68); followed by A2 and B2, both with 17.39 (12.21 - 23.66); A3: 6.52 (3.41-11.11); B1: 4.35 (1.9-8.39); D2: 2.72 (0.89 - 6.23); B3: 2.17 (0.60-5.47) and C2: 1.09 (0.13-3.87); D3, C3, A3.5 and A4: 0.54 (0.01-2.99). Shades D1 and C1 were not determined in any subject. Within the conditions of this study, A1 was the most prevalent shade in central incisors, followed by A2 and B2.

Color variations during digital imaging of facial prostheses subjected to unfiltered ambient light and image calibration techniques within dental clinics: An in vitro analysis

Background

The study aimed to evaluate 1) the amount of color variations presents within clinical images of maxillofacial prosthetic silicone specimens when photographed under different clinically relevant ambient lighting conditions, and 2) whether white balance calibration (WBC) methods were able to mitigate variations in ambient lighting.

Methods

432 measurements were acquired from standardized images of the pigmented prosthetic silicone specimens within different ambient lighting conditions (i.e., 2 windowed and 2 windowless clinics) at noon with no light modifying apparatus. The specimens were photographed once without any white balance calibration (raw), then independently alongside an 18% neutral gray card and Macbeth color chart for calibration in a post-processing (PPWBC) software, and once after camera calibration (CWBC) using a gray card. The LAB color values were extracted from the images and color variations (ΔE) were calculated after referring to the corresponding spectrophotometric values as control.

Results

Images in windowless and windowed clinics exhibited highly significant differences (p < 0.001) with spectrophotometer (control). CWBC demonstrated no significant differences (p > 0.05) in LAB values across windowed clinics. PPWBC using Macbeth color chart produced no significant differences for a* values (p > 0.05) across all clinics while PPWBC by gray card showed no significant differences (p > 0.05) in LAB values when only similar clinics (either windowed or windowless) were compared.

Conclusion

Significant color variations were present for maxillofacial prosthetic specimens owing to natural ambient light. CWBC and PPWBC using color charts were more suitable for color correction across windowed clinics while CWBC and PPWBC using gray cards had better outcomes across windowless setups.

Tooth Color Change and Erosion: Hydrogen Peroxide Versus Non-peroxide Whitening Strips

AIM

The study evaluated the efficacy and potential erosion of non-peroxide strips compared to hydrogen peroxide (HP) whitening strips (WSs).

METHODS

Color evaluation samples (N=64) were distributed into four groups and treated according to manufacturer's directions. NC: Negative control treated with water; BT: Non-peroxide Brilliant Dissolving Strips; FM: Non-peroxide Fancymay Teeth WSs; WS: Crest 3D Brilliance HP White Strips. A contact-type spectrophotometer was used to measure color at baseline (T1), 1-day posttreatment (T2), and 1-week posttreatment (T3). Teeth were cut to a rectangular block for micro-CT erosion assessment. The samples (N=30) were divided into five groups. In addition to the four groups for color assessment, a positive control (PC) treated with 0.25% citric acid was added. The samples were scanned, reconstructed, and measured for erosion depth using a micro-CT analysis program software. Kruskal-Wallis test was used to determine differences in color change and erosion depth among the groups. Tests of hypotheses were two-sided with an alpha level of 0.05.

RESULTS

The mean ΔE*ab at 1-day/1-week posttreatment were 2.4/2.5, 2.8/2.9, 2.8/3.2, and 8.6/11.0 for NC, BT, FM, and WS, respectively. There was a statistically significant difference for ΔE*ab at 1-day and 1-week posttreatment (p<0.001). Group WS had the highest color change, while the other three groups did not differ from each other (p>0.05). Mean erosion depths in microns were 0.52, 0.58, 0.42, 0.49, and 29.55 for NC, BT, FM, WS, and PC, respectively. There was a statistically significant difference among the groups (p=0.004). Group PC had the greatest erosion, while the other groups had negligible erosion that did not differ from each other (p>0.05).

CONCLUSION

Peroxide WSs had superior whitening efficacy compared to non-peroxide strips. None of the tested products compromised tooth structure integrity through enamel erosion.

Accuracy and repeatability of different intraoral instruments on shade determination compared to visual shade selection

OBJECTIVE

To evaluate the accuracy and repeatability of intraoral instruments used for shade determination compared to visual shade selection (VSS).

MATERIALS AND METHODS

A total of 20 subjects and 10 observers, balanced by gender, participated in the study. Observers performed VSS of the upper right central incisor from each subject. Instrumental shade determination of the same teeth was performed using a spectrophotometer (Easyshade V) and intraoral scanners (CEREC Omnicam, Primescan, Trios 3 and Trios 4). Vita Classical shade nomenclature was used to record the shade designation for all instruments and VSS. The accuracy of the instruments was determined by comparing the instrument readings with the most frequent visual shade selected. The percentage of accuracy was obtained by comparing the number of agreements with the number of comparisons. The percentage of repeatability was obtained by comparing the number of repeated shades with the number of shade measurements in each group. Accuracy was compared using Cochran Q test followed by pairwise comparisons using multiple McNemar's tests with Bonferroni correction. Repeatability of the instruments was evaluated using Cronbach's alpha.

RESULTS

Omnicam showed a significant lower accuracy than the other instruments (p < 0.05). No statistical difference on repeatability was found among the different instruments (p > 0.05). It was not found any statistical differences for VSS accuracy among the observers (p = 0.437) and between genders (p = 0.867).

CONCLUSION

Instrumental repeatability (≥75%) and similar accuracy between the best performed instruments (69%-77.5%) and the observers performance (65%-90%) supports the use of high-performance instruments for dental shade determination.

CLINICAL SIGNIFICANCE

Most instruments (Easyshade V, Primescan, Trios 3, and Trios 4) showed similar accuracy performance to observers in the VSS.

The effectiveness of in-office dental bleaching with and without sonic activation: A randomized, split-mouth, double-blind clinical trial

OBJECTIVE

This study was aimed at comparing the bleaching efficacy and bleaching sensitivity (BS) of two higher-concentration in-office bleaching gels (37% carbamide peroxide [CP] and 38% hydrogen peroxide [HP]) applied under two conditions: alone or in association with sonic activation.

METHODS

Fifty-six volunteers were randomly assigned in the split-mouth design into the following groups: CP, CP with sonic activation (CPS), HP, and HP with sonic activation (HPS). Two in-office bleaching sessions were performed. Color was evaluated using Vita Classical, Vita Bleachedguide, and digital spectrophotometer at baseline and at 30 days post-bleaching. Absolute risk and intensity of BS were recorded using two pain scales. All data were evaluated statistically (color changes [t test], BS [Chi-square and McNemar test], and BS intensity [VAS; t test; NRS; Wilcoxon; α = 0.05]).

RESULTS

Significant and higher whitening was observed for HP when compared with CP (p < 0.04). However, higher BS intensity was observed in the former (p < 0.001). No significant difference was observed in whitening effect or BS when the HP or CP bleaching gels were agitated (sonic application) compared with when they were not (p > 0.05).

CONCLUSION

The 37% CP gel demonstrated lower bleaching efficacy and lower BS compared with the 38% HP bleaching gel. The whitening effect was not influenced by the use of sonic activation.

CLINICAL SIGNIFICANCE

The use of 37% CP gel did not achieve the same whitening effect when compared to 38% HP gel used for in-office bleaching. The use of sonic activation offers no benefit for in-office bleaching.

A Pilot Study on the Degree of Tooth Staining Caused by Pollen Water and Chlorhexidine: In Vitro Study

Background:

Chlorhexidine oral rinse has been used as an adjuvant in the treatment of periodontal disease. However, there are drawbacks of using chlorhexidine i.e. tooth staining and other side effects, including allergy reaction. In light of the proven therapeutic properties of pollen water as well as its relatively cheap cost in the market, pollen water has a potential to be an effective alternative to chlorhexidine oral rinse. The aim of this study is to compare the degree of tooth staining influenced by water-based pollen mouthwash to the standard Chlorhexidine mouthwash using spectrophotometer.

Materials and Methods:

24 specimens from extracted intact human teeth were soaked into the three different solutions, Chlorhexidine, Pollen water (date palm pollen water suspension), and normal water. Color measurements were carried out by a spectrophotometer devise and recorded at 5 different time intervals. Color change (∆E), Chroma (C*) and Hue (H*) were analyzed and compared among the three solutions.

Results:

Overall mean ∆E was similar in all groups, significant difference between all time points was found only in pollen water. The change in C* was higher in pollen water as compared to other solutions. There was a subtle increase in H* in the Chlorhexidine samples after week 3. The H* values in pollen water were stable, but a sudden decrease was observed in week 6. The difference in H* among the three solutions was significant after 3 weeks.

Conclusion:

Within the limitation of our study, it can be concluded that Pollen water stained teeth to a lesser extent than did chlorhexidine. It might be beneficial to use Pollen water as mouthwash however, further investigation is needed regarding the efficacy of plaque control.

[Modern aspects of determining dental color in aesthetic dentistry]

One of the important factors for creating a beautiful smile is the color of the teeth, which for most people has a more important role than anatomical characteristics. The exact reproduction of the color of the tooth affects the appearance and psycho-emotional state of the patient. The purpose of this work is to review domestic and foreign literature on methods for determining the color of teeth. Methods for determining color are divided into visual, spectrophotometric, colorimetric, digital photo analysis and computer method. The most common in the practice of a dentist is visual, which is based on comparing the examined tooth with color templates. Determination of the color of teeth using scales does not give a reliable result, which is due to the small number of shades in the colors, the phenomenon of metamerism, the impossibility of converting the obtained data into digital values, etc. The hardware method for determining the color of teeth compensates for the disadvantages of the visual and has a high adaptability, which requires many interrelated factors. Due to the complexity and high cost, the devices are used mainly for research purposes. Currently, innovative methods for determining the color of teeth, based on digital and computer analysis, are being actively developed. Thus, hardware methods for determining the color of teeth significantly increase the accuracy of choosing the shade of a future aesthetic restoration or orthopedic construction, excluding subjective factors, however, they require mandatory certification. Correct color assessment and identification helps to reduce costly re-treatments and reduce warranty costs. Despite this, visual methods using scales remain in demand among practicing doctors, due to their low cost and ease of use. The accuracy of determining the color of teeth in this case depends on the professionalism of the dentist, as well as on the correctness of the photo protocol.

Is the at-home bleaching treatment applied only on the lingual surface as effective as that on the buccal surface? A randomized clinical trial

OBJECTIVES

This double-blind randomized clinical trial compared the effectiveness and bleaching sensitivity (BS) of at-home dental bleaching performed on the buccal surface and on the lingual surface.

METHODS

Using a split-mouth design, 25 patients were assigned to two bleaching groups: 10% hydrogen peroxide (White Class 10%, FGM) applied once daily for 60 min to the buccal surface (BSB) and 10% hydrogen peroxide (White Class 10%, FGM) applied once daily for 60 min to the lingual surface (LSB), both for 14 days. The color was evaluated before bleaching, after the first and second weeks, and 1 month after the bleaching using Vita Classical and Vita Bleachedguide scales and a Vita Easyshade spectrophotometer. BS was recorded daily using a 0-4 numerical rating scale and a 0-10 visual analogue scale. The following statistical tests were used: color changes (Mann-Whitney), absolute risk of BS (McNemar's exact), and the intensity of BS (Mann-Whitney). In all statistical tests, the significance level was 5%.

RESULTS

Significant bleaching was observed after the end of bleaching in both groups, with higher bleaching effectiveness for BSB when compared to LSB (p < 0.05). Regarding BS, no significant difference was observed between groups (p = 1.00).

CONCLUSIONS

The 10% hydrogen peroxide (White Class 10%, FGM) applied in at-home bleaching performed on the lingual surface did not promote a similar result of color change compared to on the buccal surface. Regarding BS, there was no significant difference between the groups.

CLINICAL RELEVANCE

The at-home bleaching performed on the lingual surface promotes a lower result in the color change. BS is similar between the groups.

CLINICAL TRIAL REGISTRATION NUMBER

RBR-283byt.

Accuracy and repeatability of different intraoral scanners on shade determination

OBJECTIVE

To evaluate the accuracy and repeatability of different intraoral scanners on shade determination.

MATERIALS AND METHODS

Ten different shades of Vita Mark II blocks were used. A disc-shape specimen (10 mm in diameter and 1 mm thick) per ceramic block was fabricated. Ten color measurements per specimen were performed by each instrument (Vita Easyshade V [control], 3shape Trios, Cerec Omnicam, Cerec Primescan) and recorded in Vita Classic color system. The number of correct shade match per instrument for each shade was recorded. Instrumental accuracy was compared using Cochran Q test and repeatability was analyzed using Cronbach's alpha.

RESULTS

There was a significant difference in the instrumental accuracy for shade determination (p < 0.001). There was no statistical difference between the Easyshade V (78%) and the 3Shape Trios (66%) (p > 0.05), with the latter being similar to the other scanners Primescan(63%) and Omnicam (57%) (p > 0.05). No significant difference was found (p > 0.05) when different shades were evaluated by the same instrument. Similar repeatability was found for the different devices, ranging from 44.3% for Easyshade to 51.9% for Omnicam.

CONCLUSION

The evaluated instruments showed less than expected repeatability and accuracy on measuring different dental shades. Therefore, caution should be exercised when using instrumental shade determination, which should be accompanied by experienced human visual assessment.

CLINICAL SIGNIFICANCE

The outcome of this study might help clinicians evaluate the performance of intraoral scanners as a shade matching tool.

[The color analysis of nanocomposite material before and after exposure to whitening toothpastes using a portable spectrophotometer]

PURPOSE

To determine the effect of whitening toothpastes on the color of a nanocomposite material using a spectrophotometer.

MATERIAL AND METHODS

The study involved 50 samples from nanocomposite restoration material which were exposed under laboratory conditions to brushing with one of 4 types of toothpastes (control with no bleaching agents, peroxide paste with carbamide, abrasive and enzyme-based pastes). Using the parameters a, b and L obtained by spectrophotometry, delta E (ΔE) value was calculated. To determine the maximum and minimum A posteriori comparisons by the Scheffe method were used to influence the delta E parameter after exposure to the pastes. Oxygen-containing paste (OZPP) had a maximum effect on the increase of the ΔE parameter, ΔE=1.03 comparing to ΔE=0.20 in control toothpaste. The isolated effect of a toothbrush resulted in a large change in the parameter ΔE, compared to the effect of a controls. However, the ΔE does not indicate the clarification of the material, but only a change in color relative to the initial measurement. As a result of spectrophotometry and statistical data processing, it was found that all pastes had a sufficient effect on the color change for the device to determine, but this change was not noticeable to the human eye.

Comparison of Bleaching Products With Up to 6% and With More Than 6% Hydrogen Peroxide: Whitening Efficacy Using BI and WI D and Side Effects - An in vitro Study

The aim of this study was to evaluate the effect of bleaching agents containing different concentrations of hydrogen peroxide (HP) on color-change and on enamel-surface in bovine teeth. Furthermore the influence on cell viability and proliferation was investigated. Two hundred and forty teeth were randomly assigned into four groups (home bleaching ≤6%, in-office bleaching ≤6%, in-office bleaching > 6% HP, and control group). Bleaching was performed after artificial staining and the bleached index (BI) as well as the whiteness index (WI_D) was measured at several time points. Chemical analysis for HP concentrations and the pH of the bleaching products was done. Furthermore, enamel surfaces of randomly selected specimens were analyzed using scanning electron microscopy (SEM) and cytotoxicity of the tested bleaching products was evaluated in vitro using dental pulp cells (DPCs) and L929 cells. A statistically significant whitening effect was observed in almost all products. As expected all investigated products resulted in decreased cell viability, however, with different values of LC50 (median lethal concentration). SEM analysis showed an analog of enamel alterations with decreasing pH, increasing exposure time, and increasing HP concentration. Bleaching agents containing a low HP concentration are considered to be effective and to have less damaging effects on enamel and tested cells.

Double-blind Randomized Study to Evaluate the Safety and Efficacy of Over-the-counter Tooth-whitening Agents Containing 2.9% Hydrogen Peroxide

OBJECTIVES

In this double-blind randomized study, we evaluated the safety and efficacy of over-the-counter (OTC) bleaching products that included 2.9% hydrogen peroxide (H₂O₂) with two methods of application: strip and paint-on.

METHODS AND MATERIALS

A commonly used product was selected for each type (strip and paint-on) of OTC bleaching agent. In total, 75 volunteers were assigned randomly into five groups: two test groups (strip and paint-on), two negative control groups (products without H₂O₂), and one positive control group (dentist-supervised home bleaching). The tooth shade was evaluated with a spectrophotometer and Vita shade guide at baseline and 2 weeks and 4 weeks after use. To document any adverse reactions, such as hypersensitivity or tissue irritation, all patients were examined and the Gingival Index (GI), Plaque Index (PI), and a visual analog scale (VAS) measuring the cold response were obtained.

RESULTS

There were significant differences among the five groups ( p<0.001). The positive control showed the greatest color changes; then, in decreasing order, the strip-type test group, paint-on-type test group, and negative controls. The strip-type bleaching agent was significantly more effective than the paint-on-type agent and the negative control, while it was significantly less effective than the dentist-supervised home bleaching. Regardless of the treatment group, the canines showed greater color changes than did the central or lateral incisors. Some cases of gingival irritation and hypersensitivity were observed, but they were mild and reversible. GI, PI, and VAS scores were not significantly changed.

CONCLUSIONS

Within the limitations of this study, the results indicated that the strip-type and paint-on-type OTC bleaching agents were significantly less efficacious than was dentist-supervised home bleaching; however, they showed acceptable safety and efficacy. The strip-type was more effective than was the paint-on-type in this study.

Randomized controlled clinical trial on bleaching sensitivity and whitening efficacy of hydrogen peroxide versus combinations of hydrogen peroxide and ozone

The clinical efficacy regarding bleaching sensitivity and tooth shade lightening using a standard hydrogen peroxide (H₂O₂) bleaching gel was compared with the additional use of ozone either before or after application of H₂O₂. Using computer-generated tables, 45 participants were randomly allocated into three groups (n = 15 each) in this investigator-driven, single-centre trial. In Group 1, upper anterior teeth were bleached using ozone (produced via a healOzone X4 device) for 60 seconds, then 38% H₂O₂ for 20 minutes; in Group 2, 38% H₂O₂ application (20 min) was followed by ozone (60 s); air produced by the healOzone machine (60 s) followed by 38% H₂O₂ (20 min) was used in Group 3 (control). Bleaching sensitivity was evaluated via visual analogue scales, and a treatment-blinded reader objectively recorded tooth shades using a colorimeter before and 24 hours after bleaching (at α = 0.05). The H₂O₂/ozone combination did not result in pain sensations, while both ozone/H₂O₂ and H₂O₂ alone increased bleaching sensitivity (p < 0.001). Teeth achieved lighter shades (higher L*/lower b* values) after bleaching in all groups (p < 0.001), while Ozone boosted lighter tooth shades, irrespective of its use before or after H₂O₂ (p < 0.05). Due to the complimentary effects, applying ozone after H₂O₂ seems preferable for bleaching.

Dental color matching: A comparison between visual and instrumental methods

The aim of this study was to compare the agreement rate (%) and color difference (ΔE*ab) of three dental color-measuring devices, with the visual shade identification. The tooth color were determined by two operators, which were advised to select a VITA classic shade tab in each other's agreement. The Shadepilot (SP), CrystalEye (CE) and ShadeVision (SV) were used to measure tooth color. Statistically analyses include agreement rate (%), color difference (ΔE*ab), McNemar test (p=0.05), Student's t-test (p=0.05) and Bland Altman scatterplots. The SP had an agreement of 56.3% with the visual shade determination, the CE 49.0% and SV 51.3%. ΔE*ab of the visually and instrumentally selected shade tabs and natural teeth were frequently above the threshold for acceptability. Comparing both methods, for SP ΔE*ab values differ in a range of clinical acceptability.

Influence of Light Conditions and Light Sources on Clinical Measurement of Natural Teeth Color using VITA Easyshade Advance 4,0® Spectrophotometer. Pilot Study

OBJECTIVES

The purpose of this study was to evaluate and compare lightness (L), chroma (C) and hue (h), green-red (a) and blue-yellow (b) character of the color of maxillary right central incisors in different light conditions and light sources.

MATERIALS AND METHODS

Two examiners who were well trained in digital color evaluation participated in the research. Intraclass correlation coefficients (ICCs) were used to analyze intra- and interobserver reliability. The LCh and L*a*b* values were determined at 08.15 and at 10.00 in the morning under three different light conditions. Tooth color was assessed in 10 subjects using intraoral spectrophotometer VITA Easyshade Advance 4.0^® set at the central region of the vestibular surface of the measured tooth.

RESULTS

Intra- and interobserver ICC values were high for both examiners and ranged from 0.57 to 0.99. Statistically significant differences in LCh and L*a*b* values measured in different time of the day and certain light condition were not found (p>0.05). Statistically significant differences in LCh and L*a*b* values measured under three different light conditions were not found, too (p>0.05).

CONCLUSIONS

VITA Easyshade Advance 4.0^® is reliable enough for daily clinical work in order to assess tooth color during the fabrication of esthtic appliances because it is not dependent on light conditions and light sources.

A Study on Possibility of Clinical Application for Color Measurements of Shade Guides Using an Intraoral Digital Scanner

PURPOSE

To assess if color measurement with intraoral scanner correlates with digital colorimeter and to evaluate the possibility of application of a digital scanner for shade selection.

MATERIALS AND METHODS

The L*a*b* values of the five shade tabs (A1, A2, A3, A3.5, and A4) were obtained with an intraoral scanner (TRIOS Pod) and a colorimeter (ShadeEye). Both devices were calibrated according to the manufacturer's instructions before measurements. Color measurement values were compared with paired t-test, and a Pearson's correlation analysis was performed to evaluate the relationship of two methods.

RESULTS

The L*a*b* values of the colorimeter were significantly different from those of the digital scanner (p < 0.001). The L* and b* values of both methods were strongly correlated with each other (both p < 0.05). The device repeatability in both methods were reported to be excellent (p < 0.05). Within the limitations of this study, color measurements with digital intraoral scanners and computer-assisted image analysis were in accordance with those of the colorimeter with respect to L* and b* values; however, all the coordinates of shade tabs were significantly different between two methods.

CONCLUSIONS

The digital intraoral scanner may not be used as the primary method of color selection in clinical practices, considering significant differences in color parameters with colorimeter. The scanner's capability in shade selection should be further evaluated.

In Vivo Evaluations of Inter-Observer Reliability Using VITA Easyshade® Advance 4.0 Dental Shade-Matching Device

OBJECTIVES

The aim of this study was to evaluate the inter-observer reliability of dental shade-matching device using an in vivo model.

MATERIALS AND METHODS

Four observers who were well trained in color assessment and handling of the dental shade-matching device determined teeth color and CIE-Lab values on maxillary right central incisors in 10 patients with completely healthy and intact dentitions. VITA Easyshade® Advance 4.0 shade-matching device was utilized to measure the central region of the labial surface of all investigated teeth, twice by each observer. The inter-observer reliability of the measurements was observed and deviations between Lab and [Formula: see text]E values between the observers were calculated. Intraclass correlation coefficients (ICCs) were used to analyze inter-observer reliability.

RESULTS

One-way ANOVA showed no statistically significant differences in color measurement of four observers in all the measured values (p>0.05). Delta E values ranged from 3.018 to 5.234. Although some small differences existed, statistically significant differences between the observers were not found (p>0.05). Inter-observer ICCs were very high for all observers (from 0.651 to 0.992).

CONCLUSION

Inter-examiner reliability of measurements using VITA Easyshade® Advance 4.0 shade-matching device was acceptable. Apart from the digital equipment, a well trained observer seems to be crucial in order to achieve correct dental color measurement.

In Vivo and in Vitro Evaluations of Repeatability and Accuracy of VITA Easyshade® Advance 4.0 Dental Shade-Matching Device

OBJECTIVES

The objective of this study was to evaluate the intra-device repeatability and accuracy of dental shade-matching device (VITA Easyshade® Advance 4.0) using both in vitro and in vivo models.

MATERIALS AND METHODS

For the repeatability assessment, the in vivo model utilized shade-matching device to measure the central region of the labial surface of right maxillary central incisors of 10 people twice. The following tooth colors were measured: B1, A1, A2, A3, C1 and C3. The in vitro model included the same six Vitapan Classical tabs. Two measurements were made of the central region of each shade tab. For the accuracy assessment, each shade tab from 3 Vitapan Classical shade guides was measured once. CIE L*a*b* values were determined. Intraclass correlation coefficients (ICCs) were used to analyze the in vitro and in vivo intra-device repeatability of the shade-matching device. The difference between in vitro and in vivo models was analyzed. Accuracy of the device tested was calculated.

RESULTS

The mean color differences for in vivo and in vitro models were 3.51 and 1.25 E units, respectively. The device repeatability ICCs for in vivo measurements ranged from 0.858 to 0.971 and for in vitro from 0.992 to 0.994. Accuracy of the device tested was 93.75%.

CONCLUSION

Within the limitations of the experiment, VITA Easyshade®Advance 4.0 dental shade-matching device enabled reliable and accurate measurement. It can be a valuable tool for the determination of tooth colours.

A novel regression model from RGB image data to spectroradiometric correlates optimized for tooth colored shades

OBJECTIVES

Objectives of this study were to correlate RGB data from the VITA Linearguide 3D Master and VITA Bleached Guide 3D Master shade guides with their spectroradiometric correlates through a regression model while indicating a methodology for validation of accuracy of digital imaging systems. Additional objectives were to provide summary RGB data and to determine a relationship between lightness and RGB values for these shade guides.

METHODS

Radiant energy measurements and images were taken with a Canon Rebel T3i and Macro Ring Lite MR-14EX for each shade tab. RGB data was extracted using Image J and compared with spectroradiometric measurements. Regression models relating the RGB data to spectroradiometric counterparts in CIE XYZ and absolute reflectance were developed using SAS 9.3. Image data was statistically analyzed to determine a relationship between RGB values and lightness.

RESULTS

Regression models with R(2) values greater than 0.99 for RGB to XYZ and greater than 0.95 for RGB to absolute reflectance were developed. Summary RGB data for the shade guides including Pearson correlation coefficients ranging between -0.92 and -0.97 for RGB related to lightness was determined.

CONCLUSIONS

A relationship between RGB and lightness for the shade guides was found. Regression models were developed that allow tooth color information to be translated from digital images to accurate shade tab correlates for color matching purposes in dentistry. This allows for optimal color accuracy when using digital imaging to translate color information and provides a method of validating digital imaging systems for color accuracy.

Effect of hydrogen peroxide concentration on enamel color and microhardness

OBJECTIVES

The aim of this study was to investigate the effect of hydrogen peroxide gels with different concentrations (20%, 25%, 30%, and 35%) on enamel Knoop microhardness (KNH) as well as on changes in dental color (C).

METHODS

Cylindrical specimens of enamel/dentin (3-mm diameter and 2-mm thickness) were obtained from bovine incisors and randomly divided into six groups (n=20), according to the concentration of the whitening gel (20%, 25%, 30%, 35%, control, thickener). After polishing, initial values of KNH0 and color measurement, assessed by spectrophotometry using the CIE L*a*b* system, were taken from the enamel surface. The gels were applied on the enamel surface for 30 minutes, and immediate values of KNHi were taken. After seven days of being stored in artificial saliva, new measures of KNH7 and color (L7* a7* b7*, for calculating ΔE, ΔL, and Δb) were made. Data were submitted to statistical analysis of variance, followed by Tukey test (p<0.05).

RESULTS

Differences in gel concentration and time did not influence the microhardness (p=0.54 and p=0.29, respectively). In relation to color changes, ΔE data showed that the 35% gel presented a higher color alteration than the 20% gel did (p=0.006).

CONCLUSION

Bleaching with 35% hydrogen peroxide gel was more effective than with the 20% gel, without promoting significant adverse effects on enamel surface microhardness.

Can demineralized enamel surfaces be bonded safely?

OBJECTIVE

To evaluate and compare the effects of enamel demineralization, microabrasion therapy and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) application on the shear bond strength (SBS) of orthodontic brackets bonded to enamel surfaces and enamel color.

MATERIALS AND METHODS

Eighty freshly extracted human maxillary premolar teeth were allocated to one of the four groups. Brackets were bonded directly to non-demineralized enamel surfaces in Group I (control group), directly to the demineralized enamel surfaces in Group II, to demineralized enamel surfaces after CPP-ACP application in Group III and to demineralized enamel surfaces after microabrasion therapy in Group IV. The samples were stored in water for 24 h at 37°C and then underwent thermocycling. The SBS in megapascals (MPa) was determined by a shear test with 0.5 mm/min crosshead speed and failure types were classified with modified adhesive remnant index scores. The data were analyzed with one-way analyses of variance (ANOVA), Tukey and chi-square tests at the α = 0.05 level.

RESULTS

Significant differences were found among the four groups (F = 21.57, p < 0.01). No significant difference was found between Group I and III (17.12 ± 2.84 and 15.08 ± 3.42 MPa, respectively) or between Group III and IV (12.82 ± 2.64 MPa). The lowest SBS value was determined in Group II (5.88 ± 2.12 MPa). Enamel demineralization, microabrasion therapy and CPP-ACP application affected enamel color significantly.

CONCLUSION

CPP-ACP application and microabrasion therapy are able to increase the decreased SBS of orthodontic brackets because of enamel demineralization.

Influence of Simulated Pulpal Pressure on Efficacy of Bleaching Gels

Aim

The aim of this study was to investigate the influence of simulated pulpal pressure on efficacy of bleaching gels.

Materials and methods

Cylindrical enamel-dentin specimens from bovine teeth (3 mm diameter, enamel and dentin layer each 1 mm thick) were divided into 4 groups, according to the bleaching treatment: negative control (non-bleached), bleached with 10% carbamide peroxide (CP), bleached with 7.5% hydrogen peroxide (HP) and bleached with 35% hydrogen peroxide. Ten percent CP gel was applied for 8 h/day and 7.5% HP for 1 h/day, during 14 days. For 35% HP treatment, two sessions of 45 minutes each were employed. In intermediate periods specimens were stored in artificial saliva. Experimental groups (n = 19) were subdivided according to the simulation of pulpal pressure (25 mm Hg) during bleaching treatment. Initial color measurement and after bleaching treatment were assessed by spectrophotometry, using CIE L*a*b* system. The data were statistically analyzed by ANOVA and Dunnett's posthoc tests (p < 0.05).

Results

There was significant difference of ∆E for all experimental groups compared to negative control group, according to Dunnett's test (p < 0.0001). There were no significant difference for total color variation (∆E) among experimental groups (p > 0.05).

Conclusion

It was concluded that all bleaching gels showed bleaching efficacy compared to non-bleached group and that the simulated pulpal pressure did not influence the bleaching outcomes of the tested gels.

Clinical significance

Although numerous in vitro studies investigating the efficacy of bleaching agents have been performed, they do not properly simulate the pulpal pressure. In order to make these studies closer to clinical conditions, it is important to reproduce these conditions in laboratory, so the results can be more reliable. This in vitro study was performed under simulated pulpal pressure, aiming to investigate its influence on dental bleaching outcomes.

How to cite this article

Borges AB, Batista GR, Arantes PT, Wiegand A, Attin T, Torres CRG. Influence of Simulated Pulpal Pressure on Efficacy of Bleaching Gels. J Contemp Dent Pract 2014;15(4):407-412.

A clinical study of the effectiveness of a light emitting diode system on tooth bleaching

The purpose of this study was to evaluate the efficacy of a Light Emitting Diode (LED) System (BriteWhite) on tooth bleaching. Method: eeth 11 and 21 of twenty one subjects were treated in the chair with a LED light and 44% carbamide peroxide gel, followed by an at-home treatment period of 14 days with 35% carbamide peroxide. The color of the teeth was measured with a spectrophotometer (L*; a*; b*) before treatment (control) and after the above mentioned two stages. The subjects were also instructed to note tooth and gingival sensitivity. Results: For the L* component a statistically significant difference (p<0.05) between base-line and directly after the LED treatment stage (whiter) was found and a complete relapse was found after the 14 day at-home treatment period. The b* component showed statistically significant differences (p<0.05) between base-line and the LED stage (less yellow more blue), with a further significant color improvement after the 14 day treatment period. For the a* component (green to red) no statistically significant change was (p>0.05) found throughout the study (Wilcox on Signed Rank Sum Test). A major color change of 1.8 units (ΔE_ab) was found after the LED treatment stage with only a further small 0.2 unit improvement after the 14 day at-home treatment stage. Tooth and gingival sensitivity scores were low (below mild) throughout the treatment stages. Conclusion: A major tooth color increase was found after the in-office LED/gel treatment stage and only an insignificant further improvement was noted after the additional 14 day at-home treatment period. Only low tooth and gingival sensitivity scores were found. A slight increase in both the sensitivity and gingival scores after the LED/gel activated stage could be observed. Overall the total color increase was low.

Enamel properties after tooth bleaching with hydrogen/carbamide peroxides in association with a CPP-ACP paste

BACKGROUND

This study evaluated the impact of bleaching teeth using blends of a CPP-ACP paste (MI Paste; MI) and carbamide/hydrogen peroxides in different proportions on surface properties of bleached enamel.

METHODS

Ninety bovine incisors were bleached with 7.5% hydrogen peroxide (HP), 16% carbamide peroxide (CP), MI and blends of HP or CP:MI at three proportions (1:1, 2:1, 1:2). Hardness and roughness were measured at baseline and after bleaching. Enamel morphology was evaluated by Scanning Electron Microscopy (SEM). The data were analyzed by two-way ANOVA for repeated measurements and Tukey's test.

RESULTS

Most of the samples bleached with MI in combination with peroxides presented increased hardness and roughness which were associated to mineral deposition, as observed by SEM images. Blends with higher fractions of MI did not offer superior benefits.

CONCLUSIONS

The use of a CPP-ACP paste mixed to carbamide/hydrogen peroxides can decrease adverse side-effects from tooth bleaching on an enamel surface.

Efficacy of a Novel At-home Bleaching Technique With Carbamide Peroxides Modified by CPP-ACP and Its Effect on the Microhardness of Bleached Enamel

This study was designed to evaluate in vitro the efficacy of a novel at-home bleaching technique using 10% or 16% carbamide peroxide modified by casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and its influence on the microhardness of bleached enamel. A total of 40 bovine incisors were divided into four groups (n=10) according to the bleaching agent used: 10% carbamide peroxide only; a blend of 10% carbamide peroxide and a CPP-ACP paste; 16% carbamide peroxide only; and a blend of 16% carbamide peroxide and a CPP-ACP paste. During the 14-day bleaching regimen, the samples were stored in artificial saliva. The Vickers microhardness and color of the teeth were assessed at baseline (T0) and immediately after the bleaching regimen (T14) using a microhardness tester and a spectrophotometer, respectively. The degree of color change was determined by the Commission Internationale de l'Eclariage (CIE) L*a*b* system (ΔE, ΔL*, Δa*, and Δb*) and Vita shade guide parameters. The data were analyzed by analysis of variance and the Tukey test (p&lt;0.05). The teeth that were bleached with a blend of peroxide (10% or 16%) and the CPP-ACP paste presented increased microhardness values at T14 compared with T0, whereas the samples that were bleached with peroxide only did not show any differences in their microhardness values. All of the bleaching agents were effective at whitening the teeth and did not show a statistically significant difference using the CIEL*a*b* system (ΔE, ΔL*, Δa*, and Δb*) or the Vita shade guide parameters. The use of a CPP-ACP paste with carbamide peroxide bleaching agents increased the bleached enamel's microhardness and did not have an influence on whitening efficacy.

A clinical study of the effectiveness of two different 10% carbamide peroxide bleaching products: a 6-month followup

The purpose of this study was to evaluate the efficacy of two different 10% carbamide peroxide bleaching products just after treatment and after a 6-month follow-up period. Methods. Two 10% carbamide peroxide products (Opalescence PF and Nite White ACP) were applied nightly for 14 days, according to the manufacturers' instructions. The color of teeth 11 and 21 of thirty-four subjects having A2 or darker teeth were measured with a spectrophotometer (L^∗; a^∗; b^∗) before treatment, just after treatment (14 days) and after 6 months. Results and Conclusions. Both products produced significant whitening of teeth with total color change (ΔE_ab^∗) of approximately 5.20 units. There was a significant improvement in all 3 color coordinates (L*, a*, and b^∗) for up to 6 months postbleaching (P < .05). Nite White showed a higher degree of relapse (27%) than Opalescence (18%) over the 6-month period. It is suggested that rebleaching after 6 months is not necessary.

In vitro evaluation of color replication of metal ceramic specimens using visual and instrumental color determinations

STATEMENT OF PROBLEM

It remains unclear whether or not the performance of intraoral colorimetric devices is accurate.

PURPOSE

The purpose of this study was to evaluate the color replication of metal ceramics using an intraoral colorimeter and visual shade determination.

MATERIAL AND METHODS

Twenty-five metal ceramic specimens were prepared to match 5 different shades (A1, B1, C3, D3, A3.5) of the Vitapan Classical shade guide. Five clinicians determined the shades of the specimens using the same shade guide. The shade determination was based on the agreement of at least 3 of the 5 observers. Instrumental shade determinations were made with an intraoral colorimeter (ShadeEye NCC) to obtain results in terms of the Vitapan Classical shade guide. Based on these shade determinations, 50 additional metal ceramic specimens (25 visually determined and 25 instrumentally determined) were prepared. The master (initial) and definitive (additional) specimens were analyzed with a spectrophotometer. L*, a*, b* values of each specimen were measured, and the color difference between the master and definitive specimens was calculated. The Wilcoxon signed rank test was used to analyze the color difference (ΔE) values (α=.05).

RESULTS

Visual shade determination produced lower ΔE values than instrumental shade determination. The differences between ΔE values of different shade determination methods were significant for master specimens of the shades B1 and A3.5 (P=.02). The ΔE value calculated from the result of instrumental determination of shade B1 (ΔE=2.97) was within the clinically acceptable limit (ΔE=3.5), whereas the ΔE value for A3.5 (4.03) exceeded the limit for clinical acceptability. The ΔE values for C3 exceeded the acceptable limit for both shade determination methods (ΔE>3.5).

CONCLUSIONS

Color replication of metal ceramic specimens using visual shade determination was more accurate compared to instrumental shade determination. The replication of the high-value shades (A₁-B₁) was observed to be reliable with both shade determination methods.

In vivo Spectrophotometric Assessment of the Tooth Whitening Effectiveness of Nite White 10% with Amorphous Calcium Phosphate, Potassium Nitrate and Fluoride, Over a 6-month Period

To clinically evaluate the effectiveness of Nite White 10% carbamide peroxide with amorphous calcium phosphate, potassium nitrate and fluoride over a 6-month follow-up period. Nite White was applied nightly for 14 days, according to the manufacturer's instructions. The color of teeth 11 and 21 of twenty one subjects was measured with a spectrophotometer (L(*); a(*); b(*)). Subjects were instructed to take note of any tooth sensitivity and gingival irritation. For all three components (L(*), a(*) and b(*)) statistical significant differences (p<0.05) in the values between base-line (pre-bleaching) and; after treatment, after 1-month, after 3-months as well as after 6-months were found (Wilcoxon Signed Rank Sum Test). Significant differences were also found amongst the ΔE(*) (ab) (0-14days) values and; ΔE(*) (ab) (0-1 month), ΔE*(ab) (0-3 months) and ΔE(*) (ab) (0-6 months). However, no significant differences were found between pairs of ΔE(*) (ab) (0-1 month), ΔE(*) (ab) (0-3 months) and ΔE(*) (ab) (0-6months). The decrease in ΔE(*) (ab) was the highest after 1 month (~30%). The highest decrease in L(*) was about 58% after 1 month. Over the 14-day treatment period tooth sensitivity was 24.5%.

CONCLUSIONS

Nite White ACP demonstrated significant tooth-whitening (unit increase = 5.29) with a low tooth sensitivity (25%) probably due to the presence of amorphous calcium phosphate, potassium nitrate, and fluoride. The whitening effect decreased the most after one month and then maintained well even after a 6 month period (units 3.89).

CLINICAL IMPLICATIONS

The product is a good tooth whitener with a color increase of about 5 units accompanied with a low sensitivity.

Influence of surfactants on the effectiveness of bleaching gels

This study evaluated the influence of surfactants on the effectiveness of 35% hydrogen peroxide (HP) and 10% carbamide peroxide (CP) bleaching gels. One hundred and forty bovine teeth were used, which were stained by immersion in a coffee, red wine, and tobacco mixture for 7 days. At the end of this process, the color measurement at baseline was taken with the Vita Easyshade spectrophotometer. The teeth were divided into seven groups: (a) negative control (NC), (b) positive control for HP (PC-35), (c) HP + Tween 20 (T20-35), (d) HP + laurel sodium sulfate (LSS-35), (e) positive control for CP (PC-10), (f) CP + Tween 20 (T20-10), and (g) CP + laurel sodium sulfate (LSS-10). Group NC was kept in artificial saliva for 21 days. Groups PC-35, T20-35, and LSS 35 received three applications of bleaching gel for 10 min; the process was repeated after 7 days. Groups PC-10, T20-10, and LSS-10 received the gel for 8 h per day for 14 days. After the bleaching process, the final color was measured. The analysis of variance and Tukey tests showed statistically significant differences for the parameters of ∆L, ∆b, and ∆E of the HP gels with surfactant and positive control group (PC-35). Within the limits of this in vitro study, the addition of surfactants to HP bleaching gel increased the bleaching effectiveness.