A comparison of toothpaste tablets and a sodium fluoride dentifrice for the control of supragingival plaque and gingivitis: A 2-week randomized controlled trial.

PURPOSE: To compare toothpaste tablets containing 0.243% sodium fluoride and a conventional sodium fluoride dentifrice for gingivitis and plaque control over a 2-week period. METHODS: Forty adult participants were randomized into two groups: Toothpaste tablets (Colgate Anywhere Travel Toothpaste Tablets) and conventional dentifrice (Colgate Cavity Protection). A blinded examiner measured the gingival and plaque index at baseline and after 2 weeks. A questionnaire was distributed at the end to determine overall satisfaction of the product used. Statistical analyses were performed separately for the gingival index and plaque index scores. Comparisons of the two treatment groups with respect to baseline and 2-week gingival index and plaque index scores were performed using Mann-Whitney U-test. Within-treatment comparisons of the gingival index and plaque index scores obtained at the 2-week examinations versus baseline were performed using Wilcoxon test. RESULTS: Both groups had statistically significant improvements in plaque control at the 2-week visit (P< 0.05). There was no statistically significant difference between groups for gingival and plaque index at the 2-week visit (P> 0.05). Overall satisfaction for both products were positive while perception on "texture/foaminess" was more negative for toothpaste tablets (P= 0.001). The results showed that toothpaste tablets' short-term performance on gingivitis and plaque control was equivalent to conventional dentifrice while the " texture/foaminess" of toothpaste tablets was found to be less appealing. CLINICAL SIGNIFICANCE: Toothpaste tablets are a relatively new form of toothpaste that can be a viable alternative to conventional dentifrice with the added benefit of an eco-friendly way of maintaining oral hygiene.

Effect of toothpaste tablets on gloss and surface roughness of resin-based composite materials.

PURPOSE: To evaluate the effects of toothpaste tablets on the gloss and surface roughness of resin-based composite materials and determine the relationship between gloss and roughness. METHODS: Rectangular jigs were designed and printed. Wells (2 mm deep x 7 mm diameter) were filled with Filtek Supreme Ultra A2B, light-cured and polished. A small-area glossmeter was used for gloss (GU) measurements and a profilometer for roughness measurements (Ra) at baseline and after challenge with each toothpaste. An automated tooth-brushing machine was set at 120 strokes/minute for a total of 10,000 strokes to evaluate four test groups with 16 specimens in each group. NC: Brushing with distilled water; TABS: Colgate Anywhere Travel Tooth Tabs; CP: Colgate Cavity Protection Toothpaste and AW: Colgate Whitening Advanced Toothpaste. Kruskal-Wallis test was used to test the difference in gloss and surface roughness among the groups and Pearson correlation was used to compare the relationship between gloss and roughness. RESULTS: There was no statistically significant difference in gloss and roughness among the four groups at baseline. At post-brushing, there was a statistically significant difference among the groups (P< 0.001) with increased roughness and decreased gloss for CP and AW when compared to TABS. There was a statistically significant correlation between post-brushing roughness and post-brushing gloss (P< 0.001, rho: -0.815). Thus, the higher the surface roughness the lower the gloss. CLINICAL SIGNIFICANCE: Toothpaste tablets retain better gloss and roughness of resin-based composite materials when compared to conventional toothpastes.

Assessing Adherence to Provider's Recommendations in Caries Risk Assessment and Management: A Retrospective Data Review.

AIM: To evaluate the distribution of caries risk category of patients at a dental institution and determine adherence to providers' recommendations. MATERIALS AND METHODS: A cross-sectional retrospective review of 1,235 patients records that included data collection on demographics, the sum of the number of decayed, missing due to caries, and filled teeth in the permanent teeth (DMFT), presence of frequent snacking, stimulated salivary flow rate, stimulated saliva pH, saliva buffering capacity, biofilm activity, caries risk category, anti-caries prescription accept/decline, and change in the caries risk category. Statistical analysis was carried out through Pearson's Chi-squared test and linear model ANOVA with a significance level of 0.05. RESULTS: Pearson's Chi-squared test showed a statistically significant difference in frequency by risk category (p < 0.001) indicating that patients were skewed toward high and extreme caries risk. Linear model ANOVA showed that higher risk categories were associated with lower salivary flow rates (p = 0.010) and higher biofilm activity (p < 0.001). About, 1 out of 3 patients were reported to have frequent snacking (N = 391, 32%). Frequent snacking patients were more likely to present with higher caries risk assessment (p < 0.001), younger age (p < 0.001), and female (p < 0.001). Despite recommendations from the dental student provider, only 27% accepted the anti-cavity prescriptions while 61% declined the recommendation. CONCLUSION: Distribution of caries risk category is not evenly distributed, but rather skewed toward high and extreme caries risk levels. Despite the identified risks, there is low adherence to the recommendations provided by healthcare providers. The results underscore the necessity for targeted interventions and initiatives aimed at fostering behavioral changes to enhance oral health outcomes. CLINICAL SIGNIFICANCE: There is a high need for targeted interventions and initiatives that promote behavioral changes to enhance oral health outcomes.

Impact of Dental Institutions' Values on Students' Intent to Practice in Underserved Communities: A Cross-sectional Study.

AIM: To evaluate how an institution's values can impact students' intent to practice in underserved areas. MATERIALS AND METHODS: The values of 71 accredited dental schools in the United States were searched and tabulated. The American Dental Education Association (ADEA) survey results were used to tabulate the desire to serve the underserved population before entering dental school and upon graduation. Additionally, responses on the total amount of educational debt on graduation was compiled for LLUSD and all other dental schools. Fisher's exact test was performed to compare the difference between the two cohorts and Wilcoxon test was used to assess difference within the groups. Tests were conducted at an alpha level of 0.05 with SAS v 9.1.3 (SAS Institute, Cary, NC, USA). RESULTS: The top five values of US dental institutions based on frequency were excellence, diversity/inclusion, integrity, innovation, and respect. There was no statistically significant difference between LLUSD and all other dental schools in their desire to serve the underserved community upon graduation (p > 0.05, in all instances). Overall, there was a trend that upon graduation, the desire to serve the underserved had less impact on students' decision-making on their career choices. This drop in the desire to serve the underserved was statistically significant within both cohorts in the year 2021 (p < 0.001). CONCLUSIONS: Dental institutions should focus on better understanding of how their values impact their students' career choices so that they can develop strategies to better align their values with the mission of addressing the dentist shortage in underserved areas. CLINICAL SIGNIFICANCE: Dental institutions' values play a major role in impacting students' career choices upon graduation and should be assessed using metrics that are measurable.

Dental Students' Knowledge, Attitude, and Confidence toward Evidence-based Dentistry: A 5-year Retrospective Study.

AIM: The purpose was to assess dental students' knowledge, attitude, and confidence toward evidence-based dentistry in five graduating Doctor of Dental Surgery (DDS) classes. MATERIALS AND METHODS: All dental students (class of 2019, 2020, 2021, 2022, and 2023) enrolled in the D3 research design course were required to take a pre-Knowledge, Attitude, and Confidence in Evidence-based Dentistry (KACE) survey. On completion of the 11-week course, a post-KACE survey was distributed to compare the differences in the three domains of evidence-based dentistry (EBD). For the knowledge domain, the responses from the 10 questions were converted to either correct (1) or wrong (0) so that the compiled scores could range from 0 to 10. The attitudes and confidence domains used a five-point Likert scale. The compiled attitude score was a sum of the responses from 10 questions yielding a range from 10 to 50. For confidence, the compiled score ranged from 6 to 30. RESULTS: The mean knowledge scores of all classes together before and after training were 2.7 and 4.4, respectively. Overall, there was a statistically significant difference between pre- and post-knowledge indicating an improvement in knowledge associated with the training (p < 0.001). The mean attitudes of all classes together before and after the training were 35.3 and 37.2, respectively. Overall, there was a statistically significant improvement in attitude (p < 0.001). The values of mean confidence of all classes together before and after the training were 15.3 and 19.5, respectively. Overall, there was a statistically significant improvement in confidence (p < 0.001). CONCLUSIONS: A dental curriculum emphasizing Evidence-based practice (EBD) resulted in increased knowledge acquisition, improved attitude, and confidence toward EBD of dental students. CLINICAL SIGNIFICANCE: Educational initiatives emphasizing evidence-based dentistry increase students' knowledge acquisition, improved attitude, and confidence toward EBD that may also translate to active implementation of EBD in their future practices.

Impact of COVID-19 on Teaching the Tooth Morphology Course to the New Generation of Learners: A Cross-sectional Study.

AIM: The purpose of the study was two-fold. First, to evaluate students' learning style and relate it to their academic performance. Second, to highlight changes implemented in the tooth morphology (TOMO) course as a response to the coronavirus disease-2019 (COVID-19) pandemic. MATERIALS AND METHODS: The study was performed during 2021-2022 with 101 dental students. Didactic lectures were delivered online and students challenged with nine quizzes and one final examination. Didactic score was calculated by averaging the scores of quizzes and the final exam. Lab score was a combination of five lab projects and the final competency. At course completion, students received a survey on their learning style and how they would like to receive feedback. Kruskal-Wallis test was used to assess differences in didactic and lab scores among groups. RESULTS: Many students perceived themselves as visual learners (39%) followed by kinesthetic (24%), aural (19%), and reader (18%). There was no difference among learning style groups in performance of didactic (p = 0.340) and lab scores (p = 0.845). Students preferred that the instructor talks them through the questions for feedback on quizzes (41%) while they preferred demonstrations when receiving feedback on their wax-ups (51%). Most students (75%) preferred a TOMO teacher that uses demonstrations. 2020-2021 marked the year of the pandemic where all lectures were delivered online and waxing projects were performed at-home. A postpandemic transformation occurred during 2021-2022, reverting to conventional in-person lab sessions while keeping online didactic lectures. CONCLUSION: We conclude that TOMO should be delivered by using various teaching styles rather than focusing on a single method while providing more demonstrations. CLINICAL SIGNIFICANCE: Teaching tooth morphology to the new generation type of learners efficiently will affect the clinical work of dental graduates.

The Outcome of a New Teledentistry Initiative in Response to the COVID-19 Pandemic: A Cross-sectional Study.

AIM: The purpose of this study was to assess the overall satisfaction of a new learning experience and evaluate the outcome of LLUSD's educational teledentistry initiative through a survey based on Kirkpatrick's multidimensional model of training evaluation. MATERIALS AND METHODS: An IRB application was approved (#5210385) for a cross-sectional study that included Loma Linda University School of Dentistry (LLUSD) dental students of the class of 2022 and 2023. The 9-question survey consisted of three sections. The first section included demographic questions on gender and the graduating class. The second section was related to perceived teaching effectiveness, attitude, behavior, and significance. The third section included an open-ended question. The survey was distributed by three student investigators. Descriptive statistics were calculated, and categorical variables were compared using the Chi-squared test (χ2 test). RESULTS: The perceived teaching effectiveness of the newly implemented educational initiative was high for increasing the ability to communicate with patients and for screening and identifying the need for referrals. A majority of students believed that teledentistry is an important means to improve patients' access to dental care and that the School has been providing a good educational environment in providing teledentistry sessions to patients. There were no significant differences in the frequencies of positive and negative responses to all questions (N = 6) by gender and by class (p >0.05, in all instances). CONCLUSIONS: Teledentistry eVisits allowed the continuation of patient contact and initial assimilation of patient information. There is potential for this educational initiative to be more actively and comprehensively implemented in the future. CLINICAL SIGNIFICANCE: New educational initiatives allow the continuation of patient contact that will ensure that students will graduate as competent oral health care providers despite challenges imposed by the pandemic.

Micro computed tomography analysis of abrasivity of toothpaste tablets compared to conventional toothpaste.

PURPOSE: To evaluate with microCT dentin and enamel abrasion depth caused by toothpaste tablets when compared to conventional toothpastes. METHODS: Dentin (N= 64) and enamel blocks (N=64) were randomized into four experimental groups of 16 specimens each for dentin and enamel. CP: Colgate Cavity Protection, served as the low abrasive toothpaste; AW: Colgate Total Advanced Whitening was used to represent a highly abrasive toothpaste. Two different types of toothpaste tablets were used. DT: Denttabs and BT: Bite tabs. To prepare the slurries, 40 mL of water was added to 25 g of each toothpaste and 4.4 g of each toothpaste tab. Blocks were brushed for a total of 10,000 and 40,000 strokes for dentin and enamel, respectively following ISO standard 11609. On completion of brushing, specimens were scanned with a microCT system. Tomographic 3D reconstruction followed by abrasion depths measurements were performed. Kruskal-Wallis procedure tested abrasion depths among the different groups. Tests of hypotheses were two-sided with an alpha level at 0.05. RESULTS: There was a statistically significant difference in dentin abrasion depth among the groups (P< 0.001). The mean dentin/enamel abrasion depths in microns were 25.3/4.4, 36.8/4.4, 66.8/3.0, and 230.3/15.5 for DT, BT, CP, and AW respectively. Dentin and enamel abrasion depth of AW was the highest and was different from all other groups after multiple comparisons (P< 0.05). CLINICAL SIGNIFICANCE: Dentin abrasivity of toothpaste tabs is negligible as determined with microCT.

Effect of charcoal dentifrices on tooth whitening and enamel surface roughness.

PURPOSE: To evaluate tooth color change and surface roughness after the use of charcoal dentifrices. METHODS: Bovine teeth (n= 64) used for color measurements were stained in tea solution and embedded in acrylic resin. Specimens were randomized into four groups of 16 specimens each. Cavity Protection (Colgate-Palmolive) was the negative control. Whitening dentifrices used were Black is White (Curaden AG); and My Magic Mud (Carbon and Clay Company) containing activated charcoal and Optic White (Colgate-Palmolive) containing hydrogen peroxide. Instrumental color measurements were performed at baseline, 1-week post-brushing, 30-day post-brushing, and 1-month follow-up. Another set of bovine teeth (n= 64) used for roughness measurements were embedded in acrylic resin and the surface ground flat. The experimental groups and brushing protocol were the same as for the color evaluation part. Surface roughness was measured with a contact type profilometer at baseline and after the last brushing session. Kruskal-Wallis procedure tested changes in color and surface roughness among the different groups. All post-hoc comparisons were conducted with Bonferroni corrections. Tests of hypotheses were two-sided with an alpha level at 0.05. RESULTS: Overall color change was not significantly different among groups at 1-week post-brushing and at 1-month follow-up. However, the hydrogen peroxide group had a significantly higher reduction in chroma in the yellow-blue axis when compared to negative control group at 30-day post-brushing and 1-month follow-up (P< 0.05). There was no significant difference in roughness among the groups at baseline (P= 0.2973) and post treatment (P= 0.8169). CLINICAL SIGNIFICANCE: The use of charcoal dentifrices did not have the claimed whitening effect but did not increase enamel surface roughness.

Dental and Dental Hygiene Students' Knowledge and Perception on Fluoride Use in Dentistry.

AIM: The 75th anniversary of community water fluoridation in the United States was celebrated in 2020. However, there are studies that stimulate polarized discussion over the use of fluoride in dentistry. The purpose of this study was to evaluate dental and dental hygiene students' knowledge and perception of fluoride use in dentistry. MATERIALS AND METHODS: A survey was conducted to gauge participant's knowledge and perception of fluoride and their opinion on the need for developing viable alternatives to fluoride. An Institutional Review Board (IRB# 5190496) application was filed and approved. A hard copy survey was distributed to all student classes at Loma Linda University School of Dentistry (U.S.) between January 13, 2020, and February 5, 2020. Descriptive data were compiled and analyzed. Knowledge-based questions were compared using Kruskal-Wallis procedure to evaluate correct percentage among different classes. Perception questions were analyzed using a Likert scale and also a Chi-squared test. All tests were two-sided with α at 0.05. RESULTS: Out of 482 students, 282 students responded (58.5%). The mean of correct responses for knowledge ranged from 49 to 69%. There was a statistically significant difference among the classes. Overall the perception of the use of fluoride in dentistry was positive, and it changed with exposure to lectures on fluoride over the years. CONCLUSION: There was a correlation between knowledge and the perception of the use of fluoride in dentistry, indicating the importance of adequate delivery of didactic teaching on knowledge of fluoride to dental and dental hygiene students. CLINICAL SIGNIFICANCE: The oral healthcare provider plays a pivotal role in communicating pertinent information on the benefits of fluoride in preventing dental caries to the general public, prompting adequate delivery of didactic teaching on this topic in dental education.

Systematic review of in vitro studies evaluating tooth bleaching efficacy.

PURPOSE: To review and assess the literature on in vitro studies evaluating tooth bleaching efficacy considering the use of a negative control, type of tooth substrate, storage medium, color evaluation methods, and evaluation time points. METHODS: The following databases were searched: PubMed (MEDLINE), Web of Science. Search used Medical Subject Headings (MeSH) in PubMed in addition to free text. The following limits were applied: English, articles published between January 1989 and October 2017. Additional free text key terms included: in vitro, tooth bleaching, placebo, negative control, overall CIELAB color change (ΔE*ab), change in shade guide units (ΔSGU), tooth color stabilization, evaluation time points, bovine teeth, and staining. Search was repeated in Web of Science but no additional articles were identified. A total of 11 studies were included for qualitative and quantitative analysis. RESULTS: The meta-analysis of nine included studies that reported ΔE*ab values, revealed that the NC statistically exceeded the perceptibility threshold (PT) of 1.2 (P< 0.05). The estimate was 2.872 with lower and upper bounds of 1.955 and 3.790, respectively. CLINICAL SIGNIFICANCE: Randomized controlled trials are gold standards to evaluate bleaching efficacy of different materials. However, in vitro studies offer a way to screen for potential bleaching efficacy. It is vital to determine an appropriate cut-off value for determining bleaching efficacy in vitro and further apply for clinical relevance.

Potential Penetration of CTAB- and MUDA-coated Gold Nanorods into Tooth Enamel.

AIM: Gold nanorods (GNRs) have gained interest as a promising carrier for antibiotics. Gold nanorods may reduce the development of antimicrobial resistance in certain microbial species. Although applications of GNRs to mitigate oral biofilms are under development, their use in the oral cavity may have adverse effects. The aim of this study was to evaluate the potential penetration of GNRs into the tooth enamel structure using confocal laser scanning microscopy (CLSM) and scanning transmission electron microscopy (STEM). MATERIALS AND METHODS: Our approach was to synthesize GNRs with cationic [cetyltrimethylammoniumbromide (CTAB)] and anionic [11-mercaptoundecanoic acid (MUDA)] surface coatings. We hypothesized that penetration would be surface coating dependent. RESULTS: Regardless of the chemical modification of the GNRs of size ∼20 nm × 8 nm, exposure of these materials did not result in superficial penetration into the enamel. CONCLUSION: Within the limitations of this study, it is concluded that the use of CLSM and STEM is a feasible approach to investigate the penetration of nanomaterials into the tooth structure. CLINICAL SIGNIFICANCE: Exposure of the enamel with chemically modified GNRs of size ∼20 nm × 8 nm will not result in superficial penetration into the enamel.

A 3 months clinical evaluation comparing two professional bleaching systems of 25% and 40% hydrogen peroxide and extended treatment outcome using a power versus a manual toothbrush.

OBJECTIVES: To assess two professional tooth bleaching products: Philips Zoom WhiteSpeed (PZW) and Ultradent Opalescence Boost PF (UOB); and to assess bleaching maintenance after use of Philips Sonicare power toothbrush (SDC) or manual toothbrush (MTB). METHODS: There was a randomized, parallel clinical trial. Eligible subjects were 18-75 years, with VITA Classical shade (VCS) of A3 on anterior teeth. Subjects were randomized to bleaching with PZW or UOB. Tooth color and shade were assessed using VITA EasyShade (VES), VCS, and VITA Bleachedguide (VBG). Subjects returned on Days 7 and 30. On Day 30, participants were dispensed either SDC or MTB for home use until Day 90. RESULTS: A total of 135 subjects completed the study. For the primary endpoint, ΔE at Day 7, a significantly larger reduction was observed for PZW than UOB (P value = .0059). Significant differences in shade were also observed at Day 7 for VCS (P value = 0.0106), and VBG (P value = .0489). On Day 90, the SDC was statistically superior to MTB in maintaining shade per VBG and VCS, but not ΔE. CONCLUSIONS: At Day 7, PZW showed statistically greater change in overall color and shade than UOB. The SDC maintained tooth shade significantly better than MTB. Both bleaching regimens were safe. CLINICAL SIGNIFICANCE: The outcomes confirm the bleaching efficacy advantage of a lower H2 O2 dose-LED accelerated professional tooth bleaching system, compared to a higher-dose H2 O2 approach. The safety assessments via clinical intraoral exam and daily logged use of subjects' desensitizing agents, and the incidence and severity of reported sensitivity, provide evidence that both professional products are safe for use. Finally, powered tooth brushing may confer an advantage to manual tooth brushing in maintaining tooth shade-change results following professional whitening.

The Effect of Delivery System and Light Activation on Tooth Whitening Efficacy and Hydrogen Peroxide Penetration.

PURPOSE: To evaluate the whitening efficacy of a new two-layer technology in-office system compared to a conventional gel-type system and determine hydrogen peroxide penetration (HPP) into the pulp cavity. MATERIALS AND METHODS: Extracted molars (n = 60) were assigned to group NC: glycerol gel; group QPRO: 20% HP varnish (Zoom Quick Pro, Philips Oral Healthcare); group ZOOM_NL: 25% HP gel (Zoom Chairside Whitening); and group ZOOM_WL: 25% HP gel (Zoom Chairside Whitening) with light-activation. HPP levels were estimated with leucocrystal-violet and horseradish-peroxidase. Instrumental color measurements were performed at baseline (T0 ), 1-day post first whitening (T1 ), 1-day post second whitening (T2 ), 1-day post third whitening (T3 ), and 1-month post whitening (T4 ). One-way analysis of variance followed by post hoc Tukey's HSD test was performed to detect difference in ΔE* and HP penetration levels (α = 0.05). RESULTS: ΔE* of NC was lower than other groups, whereas ΔE* of ZOOM_WL was greater than the other three groups, at T3 and T4 . Mean HPP level obtained from ZOOM_WL (1.568 ± 0.753 µg/mL) was significantly greater than those obtained from the other groups, whereas the mean HPP level observed in NC group (-0.131 ± 0.003 µg/mL) was significantly lower than the other groups. CONCLUSIONS: Tooth whitening efficacy and HPP levels vary based on whitening systems used. CLINICAL SIGNIFICANCE: The two-layer technology in-office varnish system may be an alternative whitening option to reduce chair time in the office. (J Esthet Restor Dent 28:313-320, 2016).

Time Course of Potassium Nitrate Penetration into the Pulp Cavity and the Effect of Penetration Levels on Tooth Whitening Efficacy.

OBJECTIVES: To establish time-course of potassium nitrate (PN) penetration into the pulp cavity, and determine whether PN pretreatment would affect whitening efficacy. MATERIALS AND METHODS: Extracted teeth (n = 100) were randomized into five groups of 20 specimens each. Relief ACP (Philips Oral Healthcare, Los Angeles, CA, USA) was applied for 0, 5, 15, 30, and 60 minutes for groups 15, respectively. A nitrate/nitrite assay kit was used for colorimetric detection of nitrate. Whitening was performed using a Zoom White Speed system (Philips Oral Healthcare) for 60 minutes. Tooth color was measured with a spectrophotometer at baseline (T0 ), 1-day post PN application (T1 ), 1-day post-whitening (T2 ), and 1-month post-whitening (T3 ). Kruskal-Wallis test was used to assess group differences in PN penetration and tooth color change. RESULTS: PN penetration differed among all groups except 2 and 3. There were no differences among groups for any baseline color parameters (p > 0.30). At T2 there was no change relative to baseline for individual components L*, a*, and b*. At T3 and T4 there was significant change relative to baseline for ΔL*, Δb*, and ΔE*, for all groups. CONCLUSIONS: PN penetration is time dependent and pretreatment with PN does not affect whitening efficacy. CLINICAL SIGNIFICANCE: Postassium nitrate penetration into the pulp cavity occurred as early as 5 minutes after application, and pretreatment with potassium nitrate containing desensitizers did not adversely affect tooth whitening efficacy. (J Esthet Restor Dent 28:S14-S22, 2016).

Effect of various tooth whitening modalities on microhardness, surface roughness and surface morphology of the enamel.

The purpose of this study was to evaluate the effect of four whitening modalities on surface enamel as assessed with microhardness tester, profilometer, and scanning electron microscopy (SEM). Whitening was performed according to manufacturer's directions for over-the-counter (OTC), dentist dispensed for home use (HW) and in-office (OW) whitening. Do-it-yourself (DIY) whitening consisted of a strawberry and baking soda mix. Additionally, negative and positive controls were used. A total of 120 enamel specimens were used for microhardness testing at baseline and post-whitening. Following microhardness testing specimens were prepared for SEM observations. A total of 120 enamel specimens were used for surface roughness testing at baseline and post-whitening (n = 20 per group). Rank-based Analysis of Covariance was performed to compare microhardness and surface roughness changes. Tests of hypotheses were two-sided with α = 0.05. There was a significant difference in Knoop hardness changes (ΔKHN) among the groups (Kruskal-Wallis test, p < 0.0001). Significant hardness reduction was observed in the positive control and DIY group (p < 0.0001). Mean surface roughness changes (ΔRa) were significantly different among the groups (Kruskal-Wallis test, p < 0.0001). Surface roughness increased in the OTC group (p = 0.03) and in the positive control (p < 0.0001). The four whitening modalities-DIY, OTC, HW and OW induced minimal surface morphology changes when observed with SEM. It can be concluded that none of the four whitening modalities adversely affected enamel surface morphology. However, caution should be advised when using a DIY regimen as it may affect enamel microhardness and an OTC product as it has the potential to increase surface roughness.

Review of the Mechanism of Tooth Whitening.

PURPOSE: This review integrated the current literature on diffusion of whitening agents, their interactions with stain molecules, and changes to the surface, with the aim of establishing a better understanding of the mechanism underlying tooth whitening. MATERIALS AND METHODS: An electronic PubMed database search, with combinations of the following terms was performed: Tooth Bleaching, Tooth Bleaching Agent, Hydrogen Peroxide, Pharmacokinetics, Tooth Permeability, Oxidation-Reduction, Tooth Demineralization, and Color. RESULTS: Tooth whitening is a dynamic process that involves diffusion of the whitening material to interact with stain molecules and also involves micromorphologic alterations on the surface and changes within the tooth that affect its optical properties. The interaction seems not to be limited to stain molecules, but rather an affinity-based interaction process that also accompanies effects on sound enamel and dentin structures. CONCLUSIONS: This review underlines that supervision by dental health professionals as recommended by the American Dental Association (ADA) Council on Scientific Affairs is critical to achieving a successful and safe whitening outcome. CLINICAL SIGNIFICANCE: The mechanism that underlies tooth whitening with the use of peroxide-based materials is a complex phenomenon encompassing diffusion, interaction, and surfaces changes within the tooth. Therefore, supervision by dental health professionals as recommended by the ADA Council on Scientific Affairs is imperative to achieve a successful and safe whitening outcome.

Effect of Light-Activated Tooth Whitening on Color Change Relative to Color of Artificially Stained Teeth.

PURPOSE: There is still controversy as to the efficacy of light activation used in tooth whitening. The purpose of this study was to evaluate the effect of light activation on tooth color change relative to the artificial dye color. MATERIALS AND METHODS: Extracted human third molars (160) were randomly distributed into eight groups of 20 specimens each based on artificial staining and use of light activation. All groups received three 45-minute sessions of in-office whitening at 3-day intervals. Color measurements were performed with an intraoral spectrophotometer at baseline prior to staining (T0), after artificial staining (T1), 1-day--(T2), and 1-week--(T3) post-whitening. Color differences were calculated relative to after artificial staining color parameters (L*1, a*1, b*1) with the use of a software analysis program enabling synchronization of two images. RESULTS: Within the same staining groups, the light-activated samples exhibited a greater color change than their nonlight-activated counterparts. However, only in the case of the yellow-stained samples at 1-day post-whitening was there a significant difference between the nonlight-activated and light-activated groups (Tukey's post hoc multiple comparison test for pairwise comparisons, p < 0.05). CONCLUSIONS: Light activation is a valid method for enhancing the efficacy of tooth whitening with respect to overall color change and works best with yellow stains. CLINICAL SIGNIFICANCE: Light activation is a valid method for enhancing the efficacy of tooth whitening with respect to overall color change and works best with yellow stains.

Repeatability in Color Measurements of a Spectrophotometer using Different Positioning Devices.

AIM: This study aimed to evaluate the repeatability of color measurements of an intraoral spectrophotometer with the use of three different methods by two operators. MATERIALS AND METHODS: A total of 60 teeth were obtained, comprising 30 human maxillary teeth [central incisors (n = 10); canines (n = 10); molars (n = 10)] and 30 artificial teeth [lateral incisors (n = 10); premolar (n = 20)]. Multiple repeated color measurements were obtained from each tooth using three measuring methods by each of the two operators. Five typodonts with alternating artificial and human teeth were made. Measurements were taken by two operators with the Vita EasyShade spectrophotometer using the custom tray (CT), custom jig (CJ) and free hand (FH) method, twice, at an interval of 2 to 7 days. Friedman test was used to detect difference among the three color measuring methods. Post hoc Wilcoxon signed-rank test with Bonferroni correction applied was used for pair-wise comparison of color measurements among the three methods. Additionally, a paired-sample t-test was used to assess a significant difference between the two duplicated measurements made on the same tooth by the same operator for each color parameter and measuring method. RESULTS: For operator A, mean (SD) overall color change-ΔE* (SD) perceived for FH, CT and CJ were 2.21(2.00), 2.39 (1.58) and 2.86 (1.92), respectively. There was statistically significant difference in perceived ΔE* in FH vs CJ (p = 0.0107). However, there were no significant differences between FH and CT (p = 0.2829) or between CT and CJ (p = 0.1159). For operator B mean ΔE* (SD) for FH, CT and CJ were 3.24 (3.46), 1.95 (1.19) and 2.45 (1.56), respectively. There was a significant difference between FH and CT (p = 0.0031). However, there were no statistically significant differences in ΔE* in FH vs CJ (p = 0.3696) or CT vs CJ (p = 0.0809). CONCLUSION: The repeatability of color measurements was different among the three measuring methods by operators. Overall, the CT method worked well for both operators. CLINICAL SIGNIFICANCE: The use of a custom tray with apertures can improve the repeatability of color measurements of an intraoral spectrophotometer.

Erosion Potential of Tooth Whitening Regimens as Evaluated with Polarized Light Microscopy.

AIMS: Tooth whitening is a widely utilized esthetic treatment in dentistry. With increased access to over-the-counter (OTC) systems concerns have been raised as to potential adverse effects associated with overuse of whitening materials. Therefore, this study aimed to evaluate enamel erosion due to different whitening regimens when used in excess of recommended guidelines. MATERIALS AND METHODS: Extracted human teeth (n = 66) were randomly divided into 11 groups (n = 6/group). Specimens were exposed to OTC products: Crest Whitestrips and 5-minute natural white and a do-it-yourself (DIY) strawberry whitening recipe. Within each regimen, groups were further divided per exposure time: specimens receiving the recommended product dosage; 5 times the recommended dosage; and 10 times the recommended dosage. Negative and positive controls were treated with grade 3 water and 1.0% citric acid, respectively. Specimens were nail-varnished to limit application to a 1 × 4 mm window. Following treatment, specimens were sectioned and erosion (drop in µm) measured using polarized light microscopy. Two-sample t-test was used to detect difference in amount of enamel erosion between negative and positive groups, while one-way analysis of variance (ANOVA), followed by post hoc Dunnett's test was used to detect difference between set of treatment groups and negative control groups or among all experimental groups. RESULTS: There was significant difference in mean amount of enamel erosion (p < 0.0001). Mean enamel erosion for positive control group was significantly greater than that for negative control group (23.50 vs 2.65 µm). There was significant effect for type of treatments on enamel erosion [F(9,50) = 25.19; p < 0.0001]. There was no significant difference between the negative control and each of treatment groups (p > 0.05 for all instances), except for Natural White_10 times treatment group (p < 0.0001) that was significantly greater than the negative control group (14.82 vs 2.65 µm). CONCLUSION: Caution is advised when using certain over-the-counter products beyond recommended guidelines as there is potential for enamel erosion. CLINICAL SIGNIFICANCE: Enamel erosion due to the overuse of whitening products varies for different modalities and products. Therefore, caution is advised when using certain over-the-counter products beyond recommended guidelines, as there is potential for enamel erosion.