Use of calcium-containing bioactive desensitizers in dental bleaching: A systematic review and meta-analysis.

BACKGROUND: Topical application of calcium-containing bioactive desensitizers (CBs) has been used to minimize bleaching-induced tooth sensitivity (TS). This study answered the research question "Is the risk of TS lower when CBs are used with dental bleaching in adults compared with bleaching without desensitizers?" TYPES OF STUDIES REVIEWED: The authors included randomized clinical trials comparing topical CB application with a placebo or no intervention during bleaching. Searches for eligible articles were performed in MEDLINE via PubMed, Cochrane Library, Brazilian Library in Dentistry, Latin American and Caribbean Health Sciences Literature, Scopus, Web of Science, Embase, and gray literature without language and date restrictions and updated in September 2022. The risk of bias was evaluated using Risk of Bias Version 2.0. The authors conducted meta-analyses with the random-effects model. The authors assessed heterogeneity with the Cochrane Q test, I2 statistics, and prediction interval. The authors used the Grading of Recommendations Assessment, Development and Evaluation approach to assess the certainty of the evidence. RESULTS: After database screening, 22 studies remained, with most at high risk of bias. No difference in the risk of TS was detected (risk ratio, 0.95; 95% CI, 0.90 to 1.01; P = .08, low certainty). In a visual analog scale, the intensity of TS (mean difference, -0.98; 95% CI, -1.36 to -0.60; P < .0001, very low certainty) was lower for the CB group. The color change was unaffected (P > .08). PRACTICAL IMPLICATIONS: Although topical CB dental bleaching did not reduce the risk of TS and color change, these agents slightly reduced the TS intensity, but the certainty of the evidence is very low.

Effectiveness and adverse effects of at-home dental bleaching with 37% versus 10% carbamide peroxide: A randomized, blind clinical trial.

PURPOSE: The aim of this trial was to evaluate bleaching effectiveness, tooth sensitivity and gingival irritation of whitening patients with 10% versus 37% carbamide peroxide (CP). METHODS: Eighty patients were selected by inclusion and exclusion criteria and randomly allocated into two groups (n = 40): 37% CP and 10% CP. In both groups, patients performed whitening for 3 weeks, 4 h/day for 10% group and 30 min/day for 37% group. Color was evaluated with Vita Classical, Vita Bleachedguide 3D Master and Spectrophotometer Easyshade, at baseline, weekly and 30 days after treatment. Absolute risk and intensity of tooth sensitivity (TS) and gingival irritation (GI) were assessed with numeric rating scale (NRS) and a visual analog scale (VAS). Color changes were compared with t-test for independent samples. TS and GI were evaluated with Fisher's exact tests. Mann-Whitney test was used for NRS, and t-tests for VAS (α = 0.05). RESULTS: The 37% CP group showed faster whitening than 10% group at 1-3 weeks. However, 1 month after conclusion, both groups showed equivalent bleaching (p = 0.06). Regarding sensitivity and gingival irritation, 10% and 37% groups met no significant differences (p > 0.05). CONCLUSION: The use of 37% CP 30 min/day showed equivalent results to 10% 4 h/day. CLINICAL SIGNIFICANCE: The use of 37% carbamide peroxide 30 min/day may decrease the time of tray use in at-home protocol for whitening because it presents equivalent results to 10% carbamide peroxide 4 h/day.

Is the use of a potassium nitrate dentifrice effective in reducing tooth sensitivity related to in-office bleaching? A randomized triple-blind clinical trial.

OBJECTIVE: The aims of this study were to evaluate whether the use of a dentifrice containing 5% potassium nitrate (KNO3 ) prior to and during in-office dental bleaching reduces bleaching-induced tooth sensitivity and affects bleaching efficiency. MATERIALS AND METHODS: Thirty-eight individuals were randomly distributed into two groups (n = 19). The experimental group performed toothbrushing using a dentifrice containing 5% KNO3 , one week before treatment and before the first and second bleaching sessions. In the control group, a placebo dentifrice without KNO3 was applied as described for the first group. Tooth sensitivity was recorded on visual analog scales (VAS) and numeric rating scales (NRS) immediately and up to 48 h after bleaching sessions. Color change at different time intervals, was evaluated with shade guide units (∆SGU) and a digital spectrophotometer (∆E CIELab 1976 and CIEDE2000) at baseline and 7, 15, and 30 days post-bleaching. Mann-Whitney test and t-test were used to evaluate TS intensity for NRS and VAS scales, respectively, and T-test was used for color difference evaluation. RESULTS: No significant difference in tooth sensitivity's absolute risk and intensity were observed between tested groups in any evaluated treatment time for NRS (p = 0.91) or VAS scales (p = 0.48). T-test showed no significant difference in both ∆E and ∆SGU tooth color among the experimental and control groups during the different evaluation times (p = 0.27). CONCLUSION: The use of a dentifrice containing 5% KNO3 does not prevent post-operatory tooth sensitivity but allows the same whitening efficiency as a regular dentifrice. CLINICAL SIGNIFICANCE: The use of a dentifrice-containing KNO3 did not prevent bleaching-induced tooth sensitivity when high-concentrated hydrogen peroxide was used for in-office bleaching.

Assessment of the effect of experimental bleaching agent with nano-bioactive material on postoperative sensitivity: A randomized, triple blind clinical trial.

OBJECTIVES: This clinical study aimed to evaluate the effect of incorporating bioactive nanoparticles (n-Bm) inside an in-office bleaching gel on the risk and intensity of tooth sensitivity (TS) and on bleaching effectiveness. MATERIALS AND METHODS: Sixty-six participants were selected and randomly assigned into two groups: control-only in-office gel and experimental-in-office gel with n-Bm. Teeth were bleached in two sessions (3 × 15-min). TS was recorded using a VAS and NRS. The color change was evaluated by subjective (VITA Classical and VITA Bleachedguide) and objective (Easyshade spectrophotometer) methods at baseline and 30 days after the end of treatment. The TS was evaluated by McNemar, Wilcoxon Signed Rank, and paired t test. The color changes between groups were compared using paired t test (α = 0.05). RESULTS: No significant differences between the groups were observed in the risk (control = 27% [95%IC 18-39]; experimental = 21% [95%IC 13-32]) and intensity of TS, as well as in the color change (p >0.05) for any color measurement. CONCLUSION: The inclusion of n-Bm into the bleaching agents did not affect the whitening effectiveness, as well as the risk and intensity of TS between groups. However, the results of the absolute risk of TS were low for both in-office gels used. CLINICAL SIGNIFICANCE: Despite no significant differences between groups, both experimental bleaching agents present suitable results with low values for TS.

Adhesive strategies in cervical lesions: systematic review and a network meta-analysis of randomized controlled trials.

OBJECTIVES: A network meta-analysis (NMA) was performed to assess which adhesive strategy is most clinically effective in treating non-carious cervical lesions (NCCLs). MATERIAL AND METHODS: Studies were identified by a systematic search of electronic databases including MEDLINE via PubMed, Brazilian Library in Dentistry (BBO), Cochrane Library, EMBASE, Latin American and Caribbean Health Sciences Literature database (LILACS), Scopus, and Web of Science without restrictions on publication year or language. The grey literature was also consulted. Only randomized clinical trials that compared different adhesive strategies in NCCLs in adult patients were included. The risk of bias was evaluated by using the Cochrane Collaboration tool. A random-effects Bayesian mixed treatment comparison model was used to compare adhesive strategies (3ER, 2ER, 2SE, and 1SE) at different follow-up times. The surface under cumulative ranking curve (SUCRA) was estimated for each strategy. Heterogeneity was assessed by using the Cochran Q test and I2 statistics. The quality of evidence was evaluated using the GRADE approach. RESULTS: A total of 5058 studies were identified, 66 of which met the eligibility criteria and of these 5 were judged "low" risk of bias and 57 were meta-analyzed. We did not observe significant differences in the NMA analysis for any two pairs of adhesives, except for the shortest follow-up for 2ER vs 3ER. The material 2SE ranked highest, although it differed only slightly from the other bonding strategies. CONCLUSIONS: No bonding strategy is better than the others. CLINICAL RELEVANCE: Adhesive efficacy cannot be characterized by its bonding strategy.

In vitro analysis of the pH stability of dental bleaching gels during in-office procedures.

BACKGROUND: Previous studies have shown that acidic bleaching gels could lead to worse collateral effects during an in-office bleaching procedure, while neutral or basic products leads towards a better experience. Considering this fact, the main purpose of this study was to evaluate the pH behavior of 6 in-office bleaching gels, compared to the information provided by their manufacturers. MATERIAL AND METHODS: Thirty enamel discs of bovine teeth were prepared, the initial colors of which were measured by a spectrophotometer and then divided into 6 groups. A pH meter was used to measure the pH every 30 seconds until the end of each procedure, when a new color evaluation was then made. The Tukey test was used for statistical analysis of the results. RESULTS: There was no difference in the color variation (ΔE) between the groups (p> 0.05). In two groups, the pH variation (ΔpH) showed neutral stability, with initial and final pH averages of 7.04 and 7.11 (p = 0.08) and 7.21 and 7.19 (p = 0.55), respectively; in another, there was alkaline stability, with an initial and final pH average of 8.54 and 8.37 (p = 0.14). In the other three brands, however, the results showed acidification, with initial and final pH averages of 6.14 and 5.22 (p = 0.001), 6.05 and 5.16 (p = 0.001) and 7.14 and 5.83 (p = 0.001), respectively. CONCLUSIONS: In 3 of the evaluated gels, a discrepancy existed between the manufacturer's information and the data obtained, which could lead, considering previous studies discussed throughout this article, to unexpected collateral effects on the patients, especially dental sensitivity. Thus, clinicians and researchers should be aware about pH stability studies of in-office bleaching gels for better predictability and safety on their clinical usage. Key words:Tooth bleaching, Bleaching agents, Hydrogen-ion concentration, Dentin sensitivity, Hydrogen peroxide.

Microporosity and polymerization contraction as function of depth in dental resin cements by X-ray computed microtomography.

This research aimed to obtain the depth dependence of polymerization contraction and microporosity from irradiated dental resin cements by X-ray computed microtomography (µCT). Samples (n = 5) of commercial Relyx U200 (RU) and AllCem Core (AC) dual-cure resin cements were injected in a cylindrical Teflon sampler (25 mm3 ) and separated according to polymerization mechanism: self-cured (not irradiated) and dual-cured (irradiated from the top surface with a LED device). The cement's volume was scanned with the µCT scanning conditions kept constant. To assess the depth dependence of polymerization contraction, it was measured the displacement of the cement mass from the sample holder at 30 vertical cuts (0.1 mm distant). To probe the microporosity, the percentage of area with presence of porosity by slice was obtained. All data were statistically treated. It was observed a positive linear correlation between depth and polymerization contraction in the irradiated groups. In the other hand, the concentration of micropores decreased with increasing depth. Furthermore, the composition of the resin cement was determinant for the correlation's coefficients of these physical properties with depth. The µCT technique showed to be useful to probe physical properties of dental restorative materials that influence in the clinical outcomes, revealing that, for thin specimens, when light cured the RU cement presented mechanical behavior more favorable for clinical applications.

Different light-activation systems associated with dental bleaching: a systematic review and a network meta-analysis.

OBJECTIVES: A systematic review and a network meta-analysis were performed to answer the following research question: "Is there any light-activation protocol capable of improving color change efficacy when associated with an in-office bleaching gel in adults?" MATERIAL AND METHODS: A search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library, and SIGLE without date and/or language restrictions in April 23, 2017 (updated on March 30, 2018). IADR abstracts (1990-2018), unpublished and ongoing trial registries, dissertations, and theses were also searched. Only randomized clinical trials conducted in adults that included at least one group treated with in-office dental bleaching with light activation were included. The risk of bias (RoB) was evaluated using the Cochrane Collaboration tool. A random-effects Bayesian-mixed treatment comparison (MTC) model was used to combine light-activated versus light-free in-office bleaching with direct light-free comparison trials. A meta-analysis with independent analysis (high- and low-concentrate hydrogen peroxide [HP]) was conducted for color change (∆E*, ∆SGU). RESULTS: After the removal of duplicates, title, and abstract screening, 28 studies remained. Nine were considered to be at a low RoB, five were at a high RoB, and the remaining were at an unclear RoB. The MTC analysis showed no significant difference in color change (ΔE* and ΔSGU) between light-activation protocols and light-free in-office bleaching, regardless of the HP concentration in the efficacy of the bleaching. CONCLUSION: No type of light-activated in-office bleaching was superior to light-free in-office bleaching for both high- and low-concentrate in-office bleaching gels (PROSPERO-CRD42017078743). CLINICAL RELEVANCE: Although many times dental professionals use "laser whitening" as a form of marketing, this study confirmed that no type of light-activation for in-office bleaching can improve the bleaching efficacy.

Didática no ensino superior: desafios e perspectivas dos docentes de Odontologia da Universidade Estadual de Ponta Grossa / Didactics in higher education: challenges and perspectives of Dentistry teachers of the State University of Ponta Grossa

O objetivo deste trabalho foi avaliar a percepção de docentes do curso de Odontologia quanto as principais dificuldades enfrentadas e as habilidades imprescindíveis para o exercício do magistério superior. Para tal, foi realizada uma pesquisa qualitativa com 47 professores do curso de Odontologia da Universidade Estadual de Ponta Grossa, divididos em dois grupos: a) tempo de atuação docente inferior a 5 anos; b) tempo de atuação docente maior que 5 anos. Após a validação do questionário, este foi encaminhado para os participantes da pesquisa responderem questões abertas sobre o exercício do magistério no ensino superior. Posteriormente à coleta dos dados, foi feita a análise descritiva das informações, exploração do material e interpretação dos resultados. Nos desafios enfrentados, os docentes com mais de 5 anos de atuação citaram a responsabilidade em formar um profissional, dificuldade em motivar os alunos e aquisição de segurança para docência como os principais. Por outro lado, docentes com atuação inferior a 5 anos apontaram o relacionamento com o aluno, insegurança profissional e obtenção do equilíbrio entre a teoria e a prática como principais desafios. Com relação às dificuldades enfrentadas atualmente, as respostas foram semelhantes para os dois grupos, sendo a falta de interesse dos alunos, falta de infraestrutura e de material de apoio para ministrar as aulas, as mais citadas. As habilidades mais mencionadas pelos professores como essenciais para o exercício da profissão incluíram a paciência, didática e necessidade de constante atualização. Pôde-se concluir que os professores enfrentam dificuldades na prática docente, independentemente do tempo de atuação (AU).

The objective of this study was to evaluate the perception of teachers of the Dentistry course regarding the main difficulties faced and the skills essential for the exercise of the higher education teaching profession. For that, a qualitative research was carried out with 47 professors of the Dentistry course at the State University of Ponta Grossa, divided into two groups: a) less than 5-year teaching experience; b) over 5-year teaching experience. After the validation of the questionnaire, it was sent to the participants of the research to answer open questions about teaching in higher education. After data collection, a descriptive analysis of the information, exploration of the material and interpretation of the results were carried out. Among the challenges faced, teachers with more than 5 years of work experience cited the responsibility to train a professional, difficulty motivating students and developing selfconfidence for teaching as the main points. On the other hand, teachers with less than 5 years of experience pointed out the relationship with the student, professional insecurity and obtaining a balance between theory and practice as the main challenges. With regard to the difficulties currently faced, the responses were similar for the two groups, namely, students' lack of interest, lack of infrastructure and support material to teach classes were the most cited. The most mentioned skills by the teachers as essential to the practice of the profession included patience, didactics and the need for constant updating. The results led to the conclusion that teachers face difficulties in teaching practice regardless of the time of performance (AU).

In-office dental bleaching with light vs. without light: A systematic review and meta-analysis.

OBJECTIVE: A systematic review and meta-analysis were performed to answer the following research question: Does light-activated in-office vital bleaching have a greater whitening efficacy and higher tooth sensitivity (TS) in comparison with in-office vital bleaching without light when used in adults? DATA AND SOURCE: Only randomized clinical trials (RCTs) involving adults who had in-office bleaching with and without light activation were included. Controlled vocabulary and keywords were used in a comprehensive search for titles and abstracts in PubMed, and this search was adapted for Scopus, Web of Science, LILACS, BBO, Cochrane Library, and SIGLE without restrictions in May 2016 and was updated in August 2017. IADR abstracts (1990-2016), unpublished- and ongoing-trial registries, dissertations, and theses were also searched. The risk-of-bias tool of the Cochrane Collaboration was used for quality assessment. The quality of the evidence was rated using the Grading of Recommendations: Assessment, Development, and Evaluation approach. Through the use of the random effects model, a meta-analysis with a subgroup analysis (low and high hydrogen peroxide concentration) was conducted for color change (ΔE*, ΔSGU) as well as the risk and intensity of TS. STUDY SELECTION: We retrieved 6663 articles, but after removing duplicates and non-relevant articles, only 21 RCTs remained. No significant difference in ΔE*, ΔSGU, and risk and intensity of TS was observed (p > .05). For ΔE and risk of TS, the quality of the evidence was graded as moderate whereas the evidence for ΔSGU and intensity of TS was graded as very low and low, respectively. CONCLUSION: Without considering variations in the protocols, the activation of in-office bleaching gel with light does not seem to improve color change or affect tooth sensitivity, regardless of the hydrogen peroxide concentration. (PROSPERO - CRD42016037630). CLINICAL RELEVANCE: Although it is commercially claimed that in-office bleaching associated with light improves and accelerates color change, this study did not confirm this belief for in-office bleaching gels with either high or low levels of hydrogen peroxide.

Polymerization shrinkage and porosity profile of dual cure dental resin cements with different adhesion to dentin mechanisms.

This research aims to probe the porosity profile and polymerization shrinkage of two different dual cure resin cements with different dentin bonding systems. The self-adhesive resin cement RelyX U200 (named RU) and the conventional Allcem Core (named AC) were analyzed by x-ray microtomography (µCT) and Scanning Electron Microscopy (SEM). Each cement was divided into two groups (n = 5): dual-cured (RUD and ACD) and self-cured (RUC and ACC). µCT demonstrated that the method of polymerization does not influence the porosity profile but the polymerization shrinkage. Fewer concentration of pores was observed for the conventional resin cement (AC), independently the method used for curing the sample. In addition, SEM showed that AC has more uniform surface and smaller particle size. The method of polymerization influenced the polymerization shrinkage, since no contraction for both RUC and ACC was observed, in contrast with results from dual-cured samples. For RUD and ACD the polymerization shrinkage was greater in the lower third of the sample and minor in the upper third. This mechanical behavior is attributed to the polymerization toward the light. µCT showed to be a reliable technique to probe porosity and contraction due to polymerization of dental cements.