In vitro bioevaluation and docking study of dihydrosphingosine and ethambutol analogues against sensitive and multi-drug resistant Mycobacterium tuberculosis.

Tuberculosis remains a major public health problem and one of the top ten causes of death worldwide. The alarming increase in multidrug-resistant and extensively resistant variants (MDR, pre-XDR, and XDR) makes the disease more difficult to treat and control. New drugs that act against MDR/XDR strains are needed for programs to contain this major epidemic. The present study aimed to evaluate new compounds related to dihydro-sphingosine and ethambutol against sensitive and pre-XDR Mycobacterium strains, as well as to characterize the pharmacological activity through in vitro and in silico approaches in mmpL3 protein. Of the 48 compounds analyzed, 11 demonstrated good to moderate activity on sensitive and MDR Mycobacterium tuberculosis (Mtb), with a Minimum Inhibitory Concentration (MIC) ranging from 1.5 to 8 µM. They presented 2 to 14 times greater potency of activity when compared to ethambutol in pre-XDR strain, and demonstrated a selectivity index varying between 2.21 and 82.17. The substance 12b when combined with rifampicin, showed a synergistic effect (FICI = 0.5) on sensitive and MDR Mtb. It has also been shown to have a concentration-dependent intracellular bactericidal effect, and a time-dependent bactericidal effect in M. smegmatis and pre-XDR M. tuberculosis. The binding mode of the compounds in its cavity was identified through molecular docking and using a predicted structural model of mmpL3. Finally, we observed by transmission electron microscopy the induction of damage to the cell wall integrity of M. tuberculosis treated with the substance 12b. With these findings, we demonstrate the potential of a 2-aminoalkanol derivative to be a prototype substance and candidate for further optimization of molecular structure and anti-tubercular activity in preclinical studies.

Performance of IS6110-LAMP assay for detection of Mycobacterium tuberculosis complex in blood and urine samples from patients with extrapulmonary tuberculosis.

BACKGROUND: The diagnosis of extrapulmonary tuberculosis (EPTB) shows numerous difficulties because of non-specific symptomatology and low sensitivity of conventional methods. Loop-mediated isothermal amplification (LAMP) is a fast and low-cost technique, which can amplify under isothermal conditions an amount of target DNA copies into approximately a billion copies. OBJECTIVE: The present study aimed to evaluate a IS6110-LAMP system for Mycobacterium tuberculosis detection in blood and urine samples from patients with EPTB. METHODS: The collected samples (n = 122) were stratified in two groups: Group EPTB - patient samples with confirmed EPTB (n = 61); Group non-TB - patient samples without TB (n = 61). The urine samples underwent decontamination, and the components of blood samples were separated (plasma and PBMC). DNA extractions were performed in all biological samples followed by IS6110-LAMP assay technique. The detection limit was evaluated through dilution curves (1:10) using Mtb reference strain (H37Rv) genomic DNA. FINDINGS: The detection limit of IS6110-LAMP was 10 fg/µL (∼10-20 bacilli/µL). The IS6110-LAMP technique sensitivity and specificity were 95.65 % and 79.25 %, respectively, with a general kappa agreement index of 0.762. MAIN CONCLUSIONS: Based on these results, IS6110-LAMP test showed considerable diagnostic parameters, being able to aid in the speed and accuracy of the final EPTB diagnosis.

Teaching of Clinical Reasoning Guided by Illness Script Theory. / Ensino do Raciocínio Clínico Orientado pela Teoria dos Scripts de Doenças.

BACKGROUND: Teaching of clinical reasoning (CR) can be facilitated by educational strategies guided by illness script theory. OBJECTIVE: To evaluate the effects of an educational strategy guided by illness script theory on the diagnostic accuracy of chest pain in medical students. METHODS: Experimental study in 3 phases, with 18 third-year medical students completing phase 3. Phases 1 and 2 had 27 students. In phase 1, each participant solved 8 clinical cases (6 of chest pain and 2 distractors). In phase 2, participants were divided into 2 groups, which distinctly trained 3 of the chest pain diagnoses from phase 1. In phase 3, after 1 week, each participant solved 8 new cases, with the same diagnoses as phase 1. Case resolution time and diagnostic accuracy were evaluated. The significance level adopted for statistical analysis was p < 0.05. RESULTS: In phase 3, both groups showed improved diagnostic accuracy and reduced case resolution time for the trained diagnoses, with no transfer of learning. For these diagnoses, the diagnostic accuracy scores in phases 1 and 3 were: group 1 = 1.00, IQR [0.00 to 1.00] versus 2.00, IQR [2.00 to 2.50], p = 0.017 and group 2 = 1.00, IQR [0.66 to 1.17] versus 3.00, IQR [1.33 to 3.00], p = 0.006. Case resolution times in seconds were: group 1: 485, IQR [450 to 583] versus 318, IQR [284 to 418], p = 0.027 and group 2: 655, IQR [543 to 740] versus 408, IQR [337 to 569], p = 0.010. CONCLUSION: The proposed strategy seems to contribute to improved diagnostic accuracy, and it may be considered for teaching CR.

FUNDAMENTO: O ensino do raciocínio clínico (RC) pode ser facilitado por estratégias educacionais orientadas pela teoria dos scripts de doenças (SD). OBJETIVO: Avaliar o efeito de uma estratégia educacional guiada pela teoria dos SD na acurácia diagnóstica (AD) da dor torácica (DT) em estudantes de medicina. MÉTODOS: Estudo experimental em 3 fases, com 18 estudantes do 3º ano concluindo a fase 3, visto que as fases 1 e 2 tiveram 27 alunos. Na fase 1, cada participante resolveu 8 casos clínicos (6 de DT e 2 distratores). Na fase 2,os participantes foram divididos em 2 grupos, que treinaram distintamente 3 dos diagnósticos de DT da fase 1.Na fase 3, após uma semana, cada participante resolveu 8 novos casos, com os mesmos diagnósticos da fase 1.O tempo de resolução dos casos (TRC) e a AD foram avaliados. O nível de significância adotado na análise estatística foi p < 0,05. RESULTADOS: Na fase 3, foram observadas melhora da AD e redução do TRC para os diagnósticos treinados em ambos os grupos, não ocorrendo transferência de aprendizagem. Para esses diagnósticos, os escores de AD nas fases 1 e 3 foram: grupo 1 = 1,00, IIQ [0,00-1,00] versus 2,00, IIQ [2,00-2,50]; p = 0,017 e grupo 2 = 1,00, IIQ [0,66-1,17] versus 3,00, IIQ [1,33-3,00]; p = 0,006. O TRC em segundos foram: Grupo 1: 485, IIQ [450-583] versus 318, IIQ [284-418]; p = 0,027 e grupo 2: 655, IIQ [543-740] versus 408, IIQ [337-569]; p = 0,010. CONCLUSÃO: A estratégia parece contribuir para melhora da AD e pode ser considerada para o ensino do RC.

Ensino do Raciocínio Clínico Orientado pela Teoria dos Scripts de Doenças / Teaching of Clinical Reasoning Guided by Illness Script Theory

Resumo Fundamento O ensino do raciocínio clínico (RC) pode ser facilitado por estratégias educacionais orientadas pela teoria dos scripts de doenças (SD). Objetivo Avaliar o efeito de uma estratégia educacional guiada pela teoria dos SD na acurácia diagnóstica (AD) da dor torácica (DT) em estudantes de medicina. Métodos Estudo experimental em 3 fases, com 18 estudantes do 3º ano concluindo a fase 3, visto que as fases 1 e 2 tiveram 27 alunos. Na fase 1, cada participante resolveu 8 casos clínicos (6 de DT e 2 distratores). Na fase 2,os participantes foram divididos em 2 grupos, que treinaram distintamente 3 dos diagnósticos de DT da fase 1.Na fase 3, após uma semana, cada participante resolveu 8 novos casos, com os mesmos diagnósticos da fase 1.O tempo de resolução dos casos (TRC) e a AD foram avaliados. O nível de significância adotado na análise estatística foi p < 0,05. Resultados Na fase 3, foram observadas melhora da AD e redução do TRC para os diagnósticos treinados em ambos os grupos, não ocorrendo transferência de aprendizagem. Para esses diagnósticos, os escores de AD nas fases 1 e 3 foram: grupo 1 = 1,00, IIQ [0,00-1,00] versus 2,00, IIQ [2,00-2,50]; p = 0,017 e grupo 2 = 1,00, IIQ [0,66-1,17] versus 3,00, IIQ [1,33-3,00]; p = 0,006. O TRC em segundos foram: Grupo 1: 485, IIQ [450-583] versus 318, IIQ [284-418]; p = 0,027 e grupo 2: 655, IIQ [543-740] versus 408, IIQ [337-569]; p = 0,010. Conclusão A estratégia parece contribuir para melhora da AD e pode ser considerada para o ensino do RC.

Abstract Background Teaching of clinical reasoning (CR) can be facilitated by educational strategies guided by illness script theory. Objective To evaluate the effects of an educational strategy guided by illness script theory on the diagnostic accuracy of chest pain in medical students. Methods Experimental study in 3 phases, with 18 third-year medical students completing phase 3. Phases 1 and 2 had 27 students. In phase 1, each participant solved 8 clinical cases (6 of chest pain and 2 distractors). In phase 2, participants were divided into 2 groups, which distinctly trained 3 of the chest pain diagnoses from phase 1. In phase 3, after 1 week, each participant solved 8 new cases, with the same diagnoses as phase 1. Case resolution time and diagnostic accuracy were evaluated. The significance level adopted for statistical analysis was p < 0.05. Results In phase 3, both groups showed improved diagnostic accuracy and reduced case resolution time for the trained diagnoses, with no transfer of learning. For these diagnoses, the diagnostic accuracy scores in phases 1 and 3 were: group 1 = 1.00, IQR [0.00 to 1.00] versus 2.00, IQR [2.00 to 2.50], p = 0.017 and group 2 = 1.00, IQR [0.66 to 1.17] versus 3.00, IQR [1.33 to 3.00], p = 0.006. Case resolution times in seconds were: group 1: 485, IQR [450 to 583] versus 318, IQR [284 to 418], p = 0.027 and group 2: 655, IQR [543 to 740] versus 408, IQR [337 to 569], p = 0.010. Conclusion The proposed strategy seems to contribute to improved diagnostic accuracy, and it may be considered for teaching CR.

Synthesis of alkynylated 1,2,4-oxadiazole/1,2,3-1H-triazole glycoconjugates: Discovering new compounds for use in chemotherapy against lung carcinoma and Mycobacterium tuberculosis.

A total of forty-three compounds were synthesized, including thirty-two new ones. Among those compounds, seventeen were selected and tested on human tumor cell lines: PC-3 (prostate adenocarcinoma), HCT-116 (colorectal tumor), NCIH-460 (lung carcinoma), SKMEL-103 (melanoma) and AGP-01 (gastric tumor). Alkynylated 1,2,4-oxadiazoles 2m, 3g and 3k exhibited antiproliferative activities against NCIH-460 in culture. Alkynylated N-cyclohexyl-1,2,4-oxadiazoles 3a-m and bis-heterocycle glucoglycero-1,2,3-triazole-N-cyclohexyl-1,2,4-oxadiazole derivatives 5a-k and 6-11 were evaluated for their in vitro efficacy towards Mycobacterium tuberculosis (Mtb) H37Ra and H37Rv strains. In general, glycerosugars conjugated to 1,2,4-oxadiazole via a 1,2,3-triazole linkage (5a, 5e, 5j, 5k, and 7) showed in vitro inhibitory activity against Mtb (H37Rv). The largest molecules bis-triazoles 10 and 11, proved inactive against TB. Probably, the absence of the N-cyclohexyl group in compound 8 and 1,2,4-oxadiazole nucleus in compound 9 were responsible for its low activity. Glucoglycero-triazole-oxadiazole derivatives 5e (10 µM) and 7 (23.9 µM) were the most promising antitubercular compounds, showing a better selective index than when tested against RAW 264.7 and HepG2 cells. Vero cell were used to investigate cytotoxicity of compounds 5a, 5h, 5j, 5k, and these compounds showed good cell viability. Further, in silico studies were performed for most active compounds (5e and 7) with potential drug targets, DprE1 and InhA of Mtb to understand possible interactions aided with molecular dynamic simulation (100ns).

Identification of nontuberculous mycobacteria species by multiplex real-time PCR with high-resolution melting.

INTRODUCTION: Nontuberculous mycobacteria (NTM) species, as human pathogens, are increasing in the world, as is the difficulty of accurately identifying them. Differential diagnosis, especially between the M. tuberculosis complex and NTM species, and the characterization of NTM species is important. This study aimed to evaluate the performance of a molecular system based on multiplex real-time PCR with high-resolution melting (HRM) for the identification and differentiation of NTM species of clinical importance of an endemic area for tuberculosis in northeastern Brazil. METHODS: The technical protocol of the molecular system was based on multiplex real-time PCR-HRM, and evaluated the sensitivity and specificity of the detection of NTM species in mycobacterial clinical isolates from the studied region. The gold standard method was specific gene sequencing. RESULTS: The sensitivity and specificity of multiplex real-time PCR-HRM modified for differentiation between NTM and M. tuberculosis were 90% and 100%, respectively. The PCR-HRM sensitivities for the characterization of NTM species (M. kansasii, M. abscesses, M. avium, and M. fortuitum) were 94.59%, 80%, 57.14%, and 54%, respectively. CONCLUSIONS: The multiplex real-time PCR-HRM modified assay has the potential to rapidly and efficiently identify nontuberculous mycobacteria of clinical importance, which is crucial for immediate implementation of the appropriate therapy and thus avoiding complications and sequelae in patients.

Didelphis albiventris as a carrier of Leptospira sp. in the central nervous tissue in the semiarid region of Northeast, Brazil.

Leptospirosis has been investigated in several species of wild animals. The white-eared opossum (Didelphis albiventris) is a mammal common in the brazilian semi-arid, so, this study aimed to investigate its role in the occurrence of the leptospirosis in the region Northeast of Brazil. 12 animals were used, from which samples were collected for the attempt of isolation, molecular detection and serological examination. There was no microbial growth, nor were any anti-Leptospira sp. antibodies found in the serological samples. The PCR detected leptospiric DNA in the central nervous system (CNS) of five animals (41.7 %). The gene in one of the samples was sequenced and showed identity with Leptospira interrogans. The presence of Leptospira sp. in the CNS of Didelphis albiventris does not allow the characterization of the studied animals as reservoirs with potential for transmission of the pathogen in the region, however it represents a site that needs to be further investigated.

Differential distribution in vitamin D receptor gene variants and expression profile in Northeast Brazil influences upon active pulmonary tuberculosis.

Tuberculosis is an infectious disease with variable outcomes. This variability is due to host immune capacity in containing the infection process initiated by the Mycobacterium tuberculosis (MTB). Vitamin D is able to modulate a very specific immune response against MTB infection, and its action relies on vitamin D receptor (VDR) binding. Altered VDR forms may compromise vitamin D pathway and proper immune response after MTB infection. Herein we assessed the relationship of five potentially functional polymorphisms from VDR: rs2228570 FokI, rs11568820 Cdx-2, rs2248098, rs1540339 and rs4760648, with tuberculosis susceptibility. The SNP rs4760648 T/T was associated with differential susceptibility to tuberculosis (OR = 2.50, 95%CI = 1.20-5.36, p = 0.01). The SNP rs1540339 presented association to both T allele (OR = 0.55, 95%CI = 0.35-0.88, p = 0.01) and the T/T genotype (OR = 0.404, 95%CI = 0.20 - 0.78, p = 0.005). The FokI T allele was identified as associated to diminished susceptibility (OR = 0.67, 95% CI = 0.45-0.99, p = 0.04) to active TB, as well as T/T genotype (OR = 0.15, 95%CI = 0.04-0.45, p = 9.58 × 10-5). We also performed the expression analyses and observed a down-regulation of VDR in patients (-10.717 FC, p = 8.42e-12), and according to the presence of associated FokI SNP, we observed that the C/T and T/T genotypes presence increases VDR expression (+ 1.25 and + 2.35 FC, p = 0.425 and p = 0.506, respectively). This study shows that vitamin D receptor variants can influence upon pulmonary tuberculosis susceptibility and VDR mRNA levels are decreased in those patients.

Identification of nontuberculous mycobacteria species by multiplex real-time PCR with high-resolution melting

Abstract INTRODUCTION: Nontuberculous mycobacteria (NTM) species, as human pathogens, are increasing in the world, as is the difficulty of accurately identifying them. Differential diagnosis, especially between the M. tuberculosis complex and NTM species, and the characterization of NTM species is important. This study aimed to evaluate the performance of a molecular system based on multiplex real-time PCR with high-resolution melting (HRM) for the identification and differentiation of NTM species of clinical importance of an endemic area for tuberculosis in northeastern Brazil. METHODS: The technical protocol of the molecular system was based on multiplex real-time PCR-HRM, and evaluated the sensitivity and specificity of the detection of NTM species in mycobacterial clinical isolates from the studied region. The gold standard method was specific gene sequencing. RESULTS: The sensitivity and specificity of multiplex real-time PCR-HRM modified for differentiation between NTM and M. tuberculosis were 90% and 100%, respectively. The PCR-HRM sensitivities for the characterization of NTM species (M. kansasii, M. abscesses, M. avium, and M. fortuitum) were 94.59%, 80%, 57.14%, and 54%, respectively. CONCLUSIONS The multiplex real-time PCR-HRM modified assay has the potential to rapidly and efficiently identify nontuberculous mycobacteria of clinical importance, which is crucial for immediate implementation of the appropriate therapy and thus avoiding complications and sequelae in patients.

Preemptive Use of Piroxicam on Tooth Sensitivity Caused By In-Office Bleaching: A Randomized Clinical Trial.

This clinical trial evaluated the effect of preemptive use of the non-steroidal anti-inflammatory drug piroxicam in a single dose 30 min prior to in-office bleaching on the prevention of tooth sensitivity (TS) reported by patients. Fifty patients were submitted to two sessions of in-office tooth bleaching with 35% hydrogen peroxide used for 2 sessions, each consisting of a single 45-min application, with an interval of 7 days between session. Thirty minutes prior to the procedure, the patient randomly received a single dose of piroxicam (200 mg) or placebo in a double-blind, randomized, crossover design. The TS was evaluated using verbal rate (VRS) and visual analog (VAS) scales during the bleaching procedure and at 24 h after each session. The color changes were assessed by the Vita Bleachedguide scale 1 week after each bleaching session. Risk of TS was calculated from the VRS and analyzed by the McNemar test, while the level of TS was analyzed by the Mann-Whitney test. For the VAS, t-tests were used to compare data from the treatments at each assessment time. Data regarding color changes were subjected to Wilcoxon and Mann-Whitney tests (α=0.05). The preemptive administration of piroxicam did not affect the risk and level of TS compared to placebo, irrespective of the assessment time. The treatment sequence did not affect bleaching effectiveness. In conclusion, the administration of a single dose of piroxicam prior to in-office tooth bleaching was unable to significantly reduce the risk and level of TS.

Preemptive use of piroxicam on tooth sensitivity caused by in-office bleaching: a randomized clinical trial

Abstract This clinical trial evaluated the effect of preemptive use of the non-steroidal anti-inflammatory drug piroxicam in a single dose 30 min prior to in-office bleaching on the prevention of tooth sensitivity (TS) reported by patients. Fifty patients were submitted to two sessions of in-office tooth bleaching with 35% hydrogen peroxide used for 2 sessions, each consisting of a single 45-min application, with an interval of 7 days between session. Thirty minutes prior to the procedure, the patient randomly received a single dose of piroxicam (200 mg) or placebo in a double-blind, randomized, crossover design. The TS was evaluated using verbal rate (VRS) and visual analog (VAS) scales during the bleaching procedure and at 24 h after each session. The color changes were assessed by the Vita Bleachedguide scale 1 week after each bleaching session. Risk of TS was calculated from the VRS and analyzed by the McNemar test, while the level of TS was analyzed by the Mann-Whitney test. For the VAS, t-tests were used to compare data from the treatments at each assessment time. Data regarding color changes were subjected to Wilcoxon and Mann-Whitney tests (α=0.05). The preemptive administration of piroxicam did not affect the risk and level of TS compared to placebo, irrespective of the assessment time. The treatment sequence did not affect bleaching effectiveness. In conclusion, the administration of a single dose of piroxicam prior to in-office tooth bleaching was unable to significantly reduce the risk and level of TS.

Resumo Este ensaio clínico avaliou o efeito do uso preemptivo do anti-inflamatório não-esteroidal piroxicam em dose única 30 minutos antes do clareamento de consultório na prevenção de sensibilidade dentária (SD) relatada pelos pacientes. Cinquenta pacientes foram submetidos a duas sessões de clareamento dental em consultório com peróxido de hidrogênio a 35% por 2 sessões, consistindo de aplicação única de 45 minutos, com um intervalo de 7 dias entres as sessões. Trinta minutos antes do procedimento, o paciente recebia aleatoriamente dose única de piroxicam (200 mg) ou do placebo em um desenho duplo-cego, randomizado e cruzado. A SD foi avaliada usando a escalas de gradação verbal (EGV) e visual analógica (EVA) durante o procedimento clareador e 24h após o procedimento. As mudanças de cor foram avaliadas usando a escala Vita Bleachedguide uma semana após cada sessão de clareamento. O risco de SD foi calculado a partir de EGV a analisado pelo teste de McNemar, enquanto o nível de SD foi analisada pelo teste de Mann-Whitney. Para EVA, testes T foram usados para comparar dados dos tratamentos em cada tempo de avaliação. Dados de mudança de cor foram submetidos aos testes de Wilcoxon e Mann-Whitney (α=0.05). A administração preemptiva de piroxicam não afetou o risco e nível de SD quando comparado ao placebo, independentemente do tempo de avaliação. A sequencia de tratamento não afetou a efetividade do clareamento. Como conclusão, a administração de dose única de piroxicam previamente ao clareamento dental de consultório não foi efetiva em reduzir significantemente o risco e nível de SD.

A simple method to increase the bleaching effectiveness of high-concentrated carbamide peroxide used for in-office bleaching.

This in vitro study aimed to evaluate the effect of two alternative clinical protocols on the tooth bleaching effectiveness of 37% carbamide peroxide. Thirty enamel-dentin blocks from bovine incisors were stained with a coffee solution for 1 week. After color measurement at baseline with a portable spectrophotometer, the blocks were bleached during two 45-min applications of 37% carbamide peroxide with a 2-day interval between bleaching procedures, according to one of the following protocols: 1) Control: placement of bleaching agent over dried enamel; 2) Moist enamel: placement of bleaching agent over enamel previously humidified with a damp gauze for 1 min; 3) Moist cotton pellet: covering the bleaching agent with a moist cotton pellet during the entire bleaching procedure. The tooth color was assessed 2 days after each bleaching procedure. The data of ΔL, Δa, Δb, and ΔE were individually analyzed using ANOVA and Tukey's test (α = 0.05). In general, applying the bleaching agent to the moist enamel resulted in lower Δa and Δb values, and higher ΔL and ΔE values than the control. No difference was observed between the control and the protocol of covering the bleaching agent with a moist cotton pellet. Regardless of the protocol, the second bleaching procedure resulted in a further increase in ΔL and ΔE, and a reduction in Δa. A further decrease in Δb was observed only for the moist enamel protocol. In conclusion, humidifying the enamel with a damp gauze prior to the placement of 37% carbamide peroxide improved the effectiveness of the bleaching.

High-concentration carbamide peroxide can reduce the sensitivity caused by in-office tooth bleaching: a single-blinded randomized controlled trial.

Objectives A single-blinded, randomized, parallel clinical trial evaluated the use of 37% carbamide peroxide (CP) on bleaching effectiveness and tooth sensitivity reported by patients undergoing in-office tooth bleaching, in comparison with the results of using 35% hydrogen peroxide. Material and Methods Forty patients were allocated to receive two sessions of in-office tooth bleaching using either 35% hydrogen peroxide (HP) or 37% CP. Each patient's sensitivity level was evaluated during and up to 24 h after bleaching. The effectiveness of the bleaching procedures was evaluated with a spectrophotometer one week after each session and 30 days after the last session. The impact of tooth bleaching on the patients' perceptions regarding smile changes, in addition to the bleaching procedures and their results, were also recorded. Absolute and relative sensitivity risks were calculated. Data on sensitivity level were analyzed using the Mann-Whitney or T-test, and data from the color evaluation were subjected to 2-way repeated measures ANOVA. Results The use of CP reduced the risk and level of tooth sensitivity to values close to zero, whereas the difference between the bleaching agents disappeared after 24 h. An increased bleaching effect was observed for HP, mainly due to an improved reduction of redness and yellowness. Participants perceived improved tooth bleaching for HP and reduced sensitivity for CP, but no differences regarding the comfort of the techniques were noted. Conclusions In our study, 37% CP resulted in reduced tooth sensitivity but decreased the tooth bleaching effectiveness. However, both bleaching agents resulted in high levels of patient satisfaction.

Color restoration and stability in two treatments for white spot lesions.

This study evaluated the effectiveness of resin infiltration or enamel microabrasion for restoring color changes caused by incipient carious lesions as well as the color stability achieved by these treatments. Enamel specimens were subjected to cariogenic challenge to produce white spot lesions (WSLs) using a microcosm biofilm model. These lesions were treated with resin infiltration or enamel microabrasion (n = 8), and color changes were measured with a spectrophotometer at baseline and after the treatments. Untreated specimens were used as a control. The treated specimens were then immersed in coffee for 1 week, and tooth color was measured again. Data for ΔL*, Δa*, Δb*, and ΔE were analyzed by two-way repeated measures ANOVA and Tukey's test (α = 0.05). Caries induction resulted in significant color changes, mainly decreased lightness. Neither resin infiltration nor enamel microabrasion were able to restore tooth color. The specimens subjected to resin infiltration and the control specimens were more susceptible to color changes following immersion in coffee. In conclusion, enamel microabrasion and resin infiltration were unable to restore the initial tooth color observed prior to WSL induction. Moreover, resin-infiltrated enamel seems more susceptible to staining solutions than enamel subjected to microabrasion.

Effect of topical application of dipyrone on dental sensitivity reduction after in-office dental bleaching: A randomized, triple-blind multicenter clinical trial.

BACKGROUND: Tooth sensitivity commonly occurs during and immediately after dental bleaching. The authors conducted a trial to compare tooth sensitivity after in-office bleaching after the use of either a topical dipyrone or placebo gel. METHODS: A split-mouth, triple-blind, randomized, multicenter clinical trial was conducted among 120 healthy adults having teeth that were shade A2 or darker. The facial tooth surfaces of the right or left sides of the maxillary arch of each patient were randomly assigned to receive either topical dipyrone or placebo gel before 2 in-office bleaching sessions (35% hydrogen peroxide) separated by 2 weeks. Visual analog and numerical rating scales were used to record tooth sensitivity during and up to 48 hours after bleaching. Tooth color change from baseline to 1 month after bleaching was measured with shade guide and spectrophotometer measures. The primary outcome variable was absolute risk of tooth sensitivity. An intention-to-treat analysis was used to analyze data from all patients who were randomly assigned to receive the dipyrone and placebo gels. RESULTS: No statically significant difference was found in the absolute risk of tooth sensitivity between the dipyrone and placebo gels (83% and 90%, respectively, P = .09; relative risk, 0.92; 95% confidence interval, 0.8 to 1.0). A whitening effect was observed in both groups with no statistically significant difference (P > .05) between them. No adverse effects were observed. CONCLUSION: Topical use of dipyrone gel before tooth bleaching, at the levels used in this study, did not reduce the risk or intensity of bleaching-induced tooth sensitivity. PRACTICAL IMPLICATIONS: Topical application of dipyrone gel does not reduce bleaching-induced tooth sensitivity.

Changes in dental esthetic perceptions of patients subjected to inoffice tooth bleaching / Mudanças nas percepções estéticas odontológicas de pacientes submetidos a clareamento dental de consultório

Objective: This study evaluated changes in the esthetic perceptions of patients subjected to inoffice tooth bleaching. Material and Methods: Fifty participants included in a clinical trial evaluating the in-office tooth bleaching answered two questionnaires about their dental esthetic perceptions. The participants answered the Orofacial Esthetic Scale (OES) questionnaire and the Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) before and after treatment. The average scores observed at baseline were compared with those recorded after tooth bleaching using the paired t-test or the Wilcoxon signed rank test (α = 0.05). Results: Improvement in tooth color (reduction of 5.1 shade guide units) had a positive impact on patients' perceptions. According to PIDAQ, tooth bleaching significantly increased the psychological impact and dental selfconfidence; and reduced esthetic concerns. The OES demonstrated improvements in participants' satisfaction for all questions, except for the one on "facial appearance". However, higher effect size was observed for the question related to tooth color, as expected. Conclusion: Tooth bleaching was associated with an overall improvement in dental esthetic perception, even when only tooth color was affected. (AU)

Objetivo: Este estudo avaliou mudanças nas percepções estéticas de pacientes submetidos a clareamento dental de consultório. Material e Métodos: Cinquenta pacientes incluídos em um ensaio clínico avaliando clareamento dental de consultório responderam a dois questionários sobre suas percepções estética odontológicas. Os participantes responderam ao questionário de escala estética orofacial (EEO) e o questionário de impacto psicossocial da estética orofacial (PIDAQ) antes e após o tratamento. As médias dos escores no início do tratamento foram comparados com aqueles mensurados após o clareamento usando o teste-T pareado ou de Wilcoxon (α = 0,05). Resultados: Melhora na cor dental (redução de 5,1 unidades da escala de cor) teve um impacto positivo nas percepções dos pacientes. De acordo com PIDAQ, o clareamento dental significativamente aumentou o impacto psicossocial e autoconfiança dental, e reduziu as preocupações estéticas. O EEO demonstrou melhora na satisfação dos participantes para todas as questões, exceto para a de "aparência facial". Entretanto, maior efeito foi observado para a questão relacionada à cor dos dentes, como esperado. Conclusão: O clareamento dental foi associado com um aumento geral na percepção estética odontológica, mesmo que apenas a cor dos dentes foi afetada. (AU)

High-concentration carbamide peroxide can reduce the sensitivity caused by in-office tooth bleaching: a single-blinded randomized controlled trial

Abstract Objectives A single-blinded, randomized, parallel clinical trial evaluated the use of 37% carbamide peroxide (CP) on bleaching effectiveness and tooth sensitivity reported by patients undergoing in-office tooth bleaching, in comparison with the results of using 35% hydrogen peroxide. Material and Methods Forty patients were allocated to receive two sessions of in-office tooth bleaching using either 35% hydrogen peroxide (HP) or 37% CP. Each patient's sensitivity level was evaluated during and up to 24 h after bleaching. The effectiveness of the bleaching procedures was evaluated with a spectrophotometer one week after each session and 30 days after the last session. The impact of tooth bleaching on the patients' perceptions regarding smile changes, in addition to the bleaching procedures and their results, were also recorded. Absolute and relative sensitivity risks were calculated. Data on sensitivity level were analyzed using the Mann-Whitney or T-test, and data from the color evaluation were subjected to 2-way repeated measures ANOVA. Results The use of CP reduced the risk and level of tooth sensitivity to values close to zero, whereas the difference between the bleaching agents disappeared after 24 h. An increased bleaching effect was observed for HP, mainly due to an improved reduction of redness and yellowness. Participants perceived improved tooth bleaching for HP and reduced sensitivity for CP, but no differences regarding the comfort of the techniques were noted. Conclusions In our study, 37% CP resulted in reduced tooth sensitivity but decreased the tooth bleaching effectiveness. However, both bleaching agents resulted in high levels of patient satisfaction.

A biofilm cariogenic challenge model for dentin demineralization and dentin bonding analysis.

OBJECTIVES: This study was designed to adapt a previously developed in vitro microcosm biofilm model to create carries-affected dentin (CAD) and establish conditions for using the model in bonding studies. MATERIALS AND METHODS: Biofilms were originated from human saliva and grown on dentin discs for 0 (sound dentin), 3, 5, 7, 14, or 21 days under intermittent cariogenic condition (n = 10). At each time point, composite cylinders were bonded to the dentin using self-etch adhesive (Clearfil SE Bond). The response variables were integrated mineral loss (ΔS), lesion depth (LD), shear bond strength (SBS), and failure mode. Data were statistically analyzed (α = 0.05). Bonded interfaces were analyzed by scanning electron microscopy (SEM), and dentin surfaces characterized by infrared spectroscopy (Fourier transform infrared spectroscopy, FTIR). RESULTS: Lower ΔS was found for sound dentin than for CAD in all experimental groups, except for the group under cariogenic challenge for 3 days. The SBS to CAD was significantly lower than control for all cariogenic challenge times. Adhesive failures were predominant in all groups. ΔS and LD had a significant negative correlation with SBS. A significant exponential decay in SBS was associated with increased ΔS values. CAD had lower mineral and amide I content and an irregular hybridization interface compared to sound dentin. CONCLUSIONS: The microcosm biofilm model was able to artificially induce CAD, which imposed challenge to the bonding of the polymeric adhesive material. CLINICAL RELEVANCE: Presence of CAD might interfere with the bonding of polymeric materials. The microcosm biofilm model proposed could be useful for preclinical dentin bonding studies.

Immediate and delayed photoactivation of self-adhesive resin cements and retention of glass-fiber posts.

The aim of this study was to evaluate the effect of immediate and delayed photoactivation of self-adhesive resin cements (SARCs) on the retention of glass-fiber posts luted into root canals. Bovine incisors were endodontically treated, and post holes of 9 mm in depth were prepared. Fiber posts were luted using one of two SARCs, BisCem (Bisco Inc., Schaumburg, USA) or RelyX Unicem clicker (3M ESPE, Saint Paul, USA), or a regular (etch-and-rinse) resin cement (AllCem; FGM, Joinvile, Brazil). Photoactivation was performed immediately, or at 5 or 10 min after cementation. Root/post specimens were transversely sectioned 7 days after luting into 1-mm-thick slices, which were submitted to push-out testing in a mechanical testing machine. Bond strength data were analyzed by two-way ANOVA and Student-Newman-Keuls' method (α = 0.05). Immediate photoactivation resulted in the highest bond strength for Unicem. BisCem demonstrated higher bond strength values when photoactivated after a 10-min delay. Immediate photoactivation yielded the lowest bond strengths for AllCem, although no differences in bond strength were observed between photoactivation delayed by 5 and 10 min. In conclusion, the moment of resin cement photoactivation may affect the intraradicular retention of fiber posts, depending upon the resin cement used for luting.

Transplante dentário: Atualização da literatura e relato de caso / Dental Transplantation: Literature Update and Case Report

Apesar dos grandes avanços da odontologia, com consequente diminuição das indicações de exodontia por doença periodontal e cárie, a prática da remoção de dentes que podem ser tratados de forma conservadora ainda é rotineira em locais onde a condição sócio-econômica é desfavorável. As terapêuticas possíveis frente a um dente perdido são geralmente por reabilitação protética, implantes e ortodontia, todavia são tratamentos que geralmente dependem de condição financeira. Desse modo, o transplante dental surge como uma opção de tratamento a todas as camadas sociais, sendo denominado por alguns pesquisadores de "prótese biológica". As principais indicações para a transferência de um dente natural do seu alvéolo para outro sítio estão relacionadas a cáries extensas, reabsorção radicular, doença periodontal, fratura coronorradicular, agenesia e aplasia de dentes, dentes inclusos. A técnica cirúrgica deve ser minimamente traumática para melhor prognóstico do dente a ser transplantado, uma vez que o ligamento periodontal não deve ser manipulado, por ser necessário à reparação dos tecidos periodontais.

Despite major advances in dentistry, with consequent reduction of the indications for extraction for periodontal disease and tooth decay, the practice of removing teeth may be treated conservatively is still routinely used in places where the socio-economic status is unfavorable. The therapeutic potential against a missing tooth are usually for prosthetic rehabilitation, implants and orthodontics, however, are treatments that often depend on financial condition. Thus, the dental transplant comes as a treatment option to all social strata, being called by some researchers "bioprosthetic". The main indications for the transfer of a natural tooth in its socket to another site is related to extensive caries, root resorption, periodontal disease, fractured coronorradicular, agenesis and aplasia of teeth, impacted teeth. The surgical procedure should be minimally traumatic to better prognosis of the tooth to be transplanted, since the periodontal ligament should not be manipulated by the need of periodontal tissue repair.