Effect of Graphene Oxide Nanoparticles Incorporation on the Mechanical Properties of a Resin-Modified Glass Ionomer Cement.

The objective of this study was to evaluate the effect of incorporating different concentrations of graphene oxide (GO) nanoparticles on the mechanical properties of a resin-modified glass ionomer cement (RMGIC). A commercial RMGIC (Resiglass R, Biodinâmica) was modified by incorporating 0.1% and 0.5% (by weight) of GO into the powder's material. An unmodified RMGIC was used as a control group. Powder samples were characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Specimens were fabricated and subjected to flexural strength (n = 15), modulus of elasticity (n = 15), Vicker's microhardness (n = 10), and surface roughness tests (n = 10). Data were analyzed using one-way ANOVA and Tukey's post hoc test (α = 5%). Experimental groups' powder demonstrated a homogeneous dispersion of GO. No statistically significant difference was observed in flexural strength (p = 0.067) and modulus of elasticity (p = 0.143) tests. The groups containing 0.1% and 0.5% GO showed significantly higher microhardness and lower surface roughness values (p < 0.001) compared to the control group. The incorporation of GO nanoparticles at concentrations of 0.1% and 0.5% improved the microhardness and surface roughness without negatively affecting the flexural strength and modulus of elasticity of an RMGIC.

Root Canal Dentin Microhardness after Contact with Antibiotic Medications: An In Vitro Study.

Background: Antibiotic pastes used as intracanal medication in cases of revascularization therapy might cause negative effects on tooth properties, such as a reduction in dentin microhardness. This in vitro study investigated dentin microhardness in three different locations distancing from the canal lumen after 20 days of treatment with a tri-antibiotic paste (ciprofloxacin, metronidazole, and minocycline), and with a double-antibiotic paste (ciprofloxacin and metronidazole), with calcium hydroxide [Ca(OH)2] UltracalTM XS-treated dentin as comparison. Material and Methods: Human mandibular premolars (n = 48) had the root canals cleaned and shaped and were used to produce dentin slices. Dentin slices remained immersed in the medications for 20 days. The Knoop microhardness (KHN) test was performed before (baseline/Day-0) and after treatment (Day-20) with the medications. Indentations were made at 25 µm, 50 µm, and 100 µm distances from the root canal lumen. The KHN was compared intra-group using Wilcoxon's test. Independent groups were compared using Mann-Whitney's and Kruskal-Wallis' tests, at α = 5%. Results: The microhardness in all the tested groups was reduced at Day-20 in comparison with Day-0 (p < 0.001) (intra-group comparison/same distances). The Day-0 values were similar, and the Day-20 values were higher for the Ca(OH)2 group (p < 0.05) (comparison between groups/same distances). Conclusions: Calcium hydroxide for 20 days would be preferred rather than antibiotic pastes to minimize the expected reduction in dentin microhardness during regenerative procedures.

Filling Material Bond Strength to Dentin Is Positively Influenced by the Agitation of Endodontic Final Irrigating Solutions.

Introduction: The final step of irrigation has been considered to of increase the bonding strength of filling material to dentin. This study investigated the impact of three final-step irrigation methods on the endodontic sealer bond strength to dentin by using a micro push-out test. Materials and Methods: Palatal roots of human maxillary molars were cleaned and shaped and randomly divided in six groups (n=15) according to the final-step irrigation method and the type of root canal sealer used. The solutions used for the final-step irrigation were 17% ethylenediaminetetraacetic acid and 2.5% sodium hypochlorite, which underwent three methods: 1) syringe-needle irrigation/conventional, 2) passive ultrasonic irrigation, and 3) XP-endo Finisher agitation. The root canal sealers used were: EndoSequence BC Sealer, and AH-Plus sealer. Roots were obturated with the single cone technique and then, cross-sectioned in 2-mm-thick slices (3 slices from each root). Push-out test was performed on the sliced specimens (cervical, middle, and apical thirds) with a universal testing machine. Bond strength values were recorded in megapascal (MPa). Subsequently, each specimen was longitudinally split to verify the type of failure. Data analysis was performed using Johnson transformation, three-way analysis of variance, Tukey's post-hoc tests, and the partial Eta squared test. Results: There were significant differences in bond strength between the sealers [AH: 4.46±2.24 and BC: 3.47±2.19 MPa (P<0.001)]; between final-step irrigation methods [passive ultrasonic irrigation: 4.52±2.25, XP-endo Finisher: 3.93±3.93 and syringe-needle irrigation/conventional: 3.37±2.51 MPa (P<0.001)], and between the root canal thirds represented by the sliced specimens [cervical: 5.45±2.39, middle: 4.14±1.99 and apical: 2.30±1.30 MPa (P<0.001)]. The interaction between the variables had no significance (P>0.05). Conclusion: Agitation of the final irrigating solution may improve the bonding of the sealer to canal walls. AH-Plus sealer had the highest bond strength. The bond strength reduced significantly towards the apical third.

Efficacy of articaine anesthesia with needle-free/Comfort-in method and conventional needle injection in dental patients with irreversible pulpitis: a randomized clinical trial.

OBJECTIVE: To assess the anesthetic efficacy of articaine with the needle-free/Comfort-in™ method compared to the conventional needle method. To assess pain during anesthesia application, onset of anesthesia and patient`s self-reported quality of life-related to oral health after the dental emergency appointment. MATERIALS AND METHODS: This parallel, randomized clinical trial was conducted by a single operator/dentist in the state of Maranhao, northeast of Brazil. Included participants were adult dental patients with one molar (maxillary) or premolar (maxillary or mandibular) tooth diagnosed with symptomatic irreversible pulpitis. The primary outcome was the anesthetic efficacy, measured using a combination of electrical and cold pulp tests (cold + EPT) and the Numerical Rating Scale (NRS). Secondary outcomes were pain during anesthesia application, onset of anesthesia, and patient`s quality-of-life (measured with the OHIP-14). RESULTS: 62 patients were randomized in the anesthesia needle-free group and Comfort-in group (34.26 ± 10.786 × 33.29 ± 8.399 years old, respectively). The group of patients in the Comfort-in group had 71.0% success. Patients from the Comfort-in group reported statistically lower pain during the anesthesia application than patients from the conventional group (2.13 ± 2.172 × 6.03 ± 3.146 NRS scores, respectively) as well as immediately after the anesthetic procedure. Patients self-reported negative impact in quality of life was similar between groups before (p > 0.05) and after (p > 0.05) the dental emergency. CONCLUSIONS: Comfort-in™ had similar efficacy to the conventional needle method. CLINICAL RELEVANCE: This trial showed that it is possible to anesthetize patients with tooth pulpits without using needles to provide comfort mainly to anxious patients.

Oral Health-Related Quality of Life among Adolescents in the First 6 Months of Fixed Orthodontic Therapy.

Clarification on disabilities that may arise during orthodontic treatment allows patients to have more realistic expectations. This prospective study assessed the impact of fixed orthodontic therapy on adolescents' quality of life over 6 months. A total of 78 adolescents aged 11-17 years were included. Quality of life was measured using the Child Perceptions Questionnaire (CPQ11-14, short form) at five moments: before treatment (T0), one week (T1), one month (T2), three months (T3), and six months (T4) after treatment initiation. Multiple and pairwise comparisons were conducted for CPQ11-14 scores (Friedman and Wilcoxon test; effect size). Changes in the quality of life were assessed as mean differences (T0-T1 and T0-T4) in total and domain scores (Kruskal-Wallis and Mann-Whitney test) (α = 5%). Significant differences were observed between T0 and T4 in the oral symptoms' domain (p < 0.001), and between T0 and T1, T2, T3, and T4 for emotional well-being (p < 0.001 for all). Significant differences in impact were also found between T0 and T2, T3, and T4 with regard to social well-being (p = 0.004, =0.049, and <0.001, respectively). Orthodontic therapy positively impacted the emotional and social aspects of adolescents' quality of life. Negative effects were primarily related to pain, mouth sores, and difficulty biting or chewing. Understanding the symptoms and feelings of orthodontic patients aids professionals in decision-making.

Tissue repair capacity of bioceramic endodontic sealers in rat subcutaneous tissue.

This study aimed to evaluate the tissue repair capacity of four bioceramic endodontic sealers by quantifying type I and III collagen fibers. The following sealers were tested: EndoSequence BC Sealer (Brasseler, Brasseler, Savannah, USA), Bio C Sealer (Angelus, Londrina, Brazil), Bioroot RCS (Septodont, Santa Catarina, Brazil), and Sealer Plus BC (MKLife, Porto Alegre, Brazil). Polyethylene tubes 1.5 mm in diameter and 1 cm in length containing the endodontic sealers were implanted in the subcutaneous tissue of five rats (Rattus norvegicus albinus, Wistar lineage). After 14 days, the animals were euthanized, and collagen fibers were quantified from the histological tissue sections. Given a non-normal distribution of the data, a gamma regression with log link function was employed and implemented through the generalized linear models module, was used to test whether there was a significant difference between the sealers. The pairwise comparison was performed using Least significant difference. There were significant differences between the sealers for type I (p=0.001), type III (p=0.023), and total collagen (p=0.002). Overall, Bioroot sealer was statistically superior to the other sealers, except in the analysis of type III collagen, in which there was no difference between the Bioroot sealer and Bio C Sealer sealer and the control group (p>0.05). Bioroot RCS bioceramic endodontic sealer stimulates a greater production of collagen.

Tissue repair capacity of bioceramic endodontic sealers in rat subcutaneous tissue

Abstract This study aimed to evaluate the tissue repair capacity of four bioceramic endodontic sealers by quantifying type I and III collagen fibers. The following sealers were tested: EndoSequence BC Sealer (Brasseler, Brasseler, Savannah, USA), Bio C Sealer (Angelus, Londrina, Brazil), Bioroot RCS (Septodont, Santa Catarina, Brazil), and Sealer Plus BC (MKLife, Porto Alegre, Brazil). Polyethylene tubes 1.5 mm in diameter and 1 cm in length containing the endodontic sealers were implanted in the subcutaneous tissue of five rats (Rattus norvegicus albinus, Wistar lineage). After 14 days, the animals were euthanized, and collagen fibers were quantified from the histological tissue sections. Given a non-normal distribution of the data, a gamma regression with log link function was employed and implemented through the generalized linear models module, was used to test whether there was a significant difference between the sealers. The pairwise comparison was performed using Least significant difference. There were significant differences between the sealers for type I (p=0.001), type III (p=0.023), and total collagen (p=0.002). Overall, Bioroot sealer was statistically superior to the other sealers, except in the analysis of type III collagen, in which there was no difference between the Bioroot sealer and Bio C Sealer sealer and the control group (p>0.05). Bioroot RCS bioceramic endodontic sealer stimulates a greater production of collagen.

Resumo Este estudo visou avaliar a capacidade de reparação de tecidos de quatro cimentos endodônticos biocerâmicos através da quantificação de fibras colágenas de tipo I e III. Foram testados os seguintes cimentos: EndoSequence BC Sealer (Brasseler, Brasseler, Savannah, EUA), Bio C Sealer (Angelus, Londrina, Brasil), Bioroot RCS (Septodont, Santa Catarina, Brasil), e Sealer Plus BC (MKLife, Porto Alegre, Brasil). Foram implantados tubos de polietileno de 1,5 mm de diâmetro e 1 cm de comprimento contendo os cimentos endodônticos no tecido subcutâneo de cinco ratos (Rattus norvegicus albinus, linhagem Wistar). Após 14 dias, os animais foram eutanasiados e as fibras colágenas foram quantificadas a partir de cortes histológicos do tecido. Diante de uma distribuição não-normal dos dados, uma regressão gama com função de ligação log, implementada por meio do módulo de modelos lineares generalizados, foi empregada para testar se havia diferença significativa entre os cimentos. A comparação dois a dois foi realizada utilizando Least significant difference. Houve diferença significativa entre os cimentos para os colágenos tipo I (p=0,001), tipo III (p=0,023) e colágeno total (p=0,002). No geral, o cimento Bioroot foi estatisticamente superior aos demais cimentos, com exceção na análise do colágeno tipo III na qual não houve diferença entre o cimento Bioroot e o cimento Bio C Sealer e o grupo controle (p>0,05). O cimento endodôntico biocerâmico Bioroot RCS foi capaz de estimular uma maior produção de colágeno.

Apical Sealing and Bioactivity of an Experimental Gutta-Percha Containing Niobium Phosphate Bioglass.

This study evaluated the apical sealing ability and bioactivity of an experimental gutta-percha containing niobium phosphate bioglass. Thirty-six human premolars were endodontically prepared and divided into three groups: GPC-filling with conventional gutta-percha; GBC-filling with bioceramic gutta-percha (EndoSequence BC); GNB-filling with experimental gutta-percha containing niobophosphate. Teeth were stored in tubes containing 2 mL of simulated body fluid (SBF) solution in an oven for 30 days. Then, the samples were immersed in lanthanum nitrate solution and analyzed for apical nanoleakage (NI) with a scanning electron microscope (SEM/EDS) and transmission electron microscope (TEM). Gutta-percha specimens were immersed for 28 days (SBF) and analyzed in SEM/EDS and X-ray diffraction (XRD) to assess bioactivity. NI data originated from the SEM/EDS were analyzed using the Kruskal-Wallis test (α = 5%). NI data originated from TEM and bioactivity were descriptively reported. Statistical analysis did not detect a significant difference between groups (p = 0.13) for NI. In the bioactivity analysis, an abundant layer of hydroxyapatite was identified only in the surface of the GNB group samples. The gutta-percha containing niobophosphate bioglass promoted an apical sealing similar to EndoSequence BC, in addition to demonstrating bioactivity through the deposition of hydroxyapatite on the surface of the material after immersion in SBF.

Effect of Bioactive Filler Addition on the Mechanical and Biological Properties of Resin-Modified Glass Ionomer.

The maintenance of affected dentin can promote the greater conservation of tooth structure. The development of materials that have properties capable of reducing the demineralizing potential and/or even helping in dental remineralization is important for conservative dentistry. This study aimed to evaluate, in vitro, the alkalizing potential, fluoride as well as calcium ion release ability, antimicrobial activity, and dentin remineralization properties of resin-modified glass ionomer cement (RMGIC) incorporated with a bioactive filler (niobium phosphate (NbG) and bioglass (45S5)). The study samples were grouped into RMGIC, NbG, and 45S5. The materials' alkalizing potential, ability to release calcium as well as fluoride ions, and antimicrobial properties concerning Streptococcus mutans UA159 biofilms were analyzed. The remineralization potential was evaluated using the Knoop microhardness test, which was performed at different depths. The alkalizing and fluoride release potential was higher for the 45S5 group (p < 0.001) over time. An increase in the microhardness of demineralized dentin was observed in the 45S5 and NbG groups (p < 0.001). No differences in biofilm formation were observed between the bioactive materials, although 45S5 exhibited lower biofilm acidogenicity at different time points (p < 0.001) and greater calcium ion release in the microbial environment. A resin-modified glass ionomer cement enriched with bioactive glasses, particularly 45S5, is a promising alternative for the treatment of demineralized dentin.

Cases of Maxillofacial Trauma Treated at Hospitals in a Large City in Northeastern Brazil: Cross-Sectional Study.

Maxillofacial trauma is associated with facial deformation, loss of function, emotional and social impacts, and high financial costs. This study investigated cases of maxillofacial trauma in a large Brazilian city through a cross-sectional study conducted at two public and two private hospitals. Primary data of 400 patients were collected through a questionnaire, clinical examination, and tomography. Statistical analysis at the 5% significance level was performed. Motorcycle accident was the major cause of trauma (41%); the most frequent trauma and treatment were mandibular fracture (24.3%) and surgery (71%), respectively. The female sex was more affected only regarding domestic accidents (p = 0.041) and falls (p < 0.001). Motorcycle accidents were more prevalent among 20 to 29 year-olds (p < 0.001), followed by physical aggression (p < 0.001) and sports accidents (p = 0.004). Falls were more frequent among 40 to 59 year-olds (p < 0.001). Mandibular fracture affected males and 20 to 29 year-olds more and was mainly associated with motorcycle accidents (48.2%) and physical aggression (22.7%) (p = 0.008). Nose fracture was more frequent in falls (29.6%), physical aggression (22.5%), and sports accidents (21.1%) (p < 0.001). Compound fracture was associated with motorcycle accidents (84.2%; p = 0.028). Maxillofacial trauma (mandibular, nasal, and zygomatic fractures) was associated with motorcycle accidents, physical aggression, and falls. Surgical treatment, hospital care, and public services were the most frequent.

Postoperative Pain Following Root Canal Instrumentation Using ProTaper Next or Reciproc in Asymptomatic Molars: A Randomized Controlled Single-Blind Clinical Trial.

Aim: The development of postoperative pain following root canal instrumentation may impair patient's comfort and undermine their trust in the dentist. This study assessed the effect of root canal instrumentation techniques (rotary (PTN; ProTaper Next®) and reciprocating (R; Reciproc®)) on the postoperative pain intensity (primary outcome) and tenderness on biting (secondary outcome) of patients' asymptomatic molars. Methodology: This study protocol was registered with ReBec-WHO (U1111-1182-2800). From a pool of 112 patients evaluated for eligibility (healthy adults (≤18 years old)), with a single asymptomatic molar (maxillary or mandibular) indicated for root canal treatment, diagnosed with asymptomatic irreversible pulpitis (including chronic hyperplastic pulpitis), 75 were randomly allocated in similar proportions to receive the intervention (two-appointment root canal therapy) in either the PTN or R group. The allocated procedures were performed using standardized protocols. Participants (blinded to the instrumentation technique) rated their pain intensity at 6, 12 and 24 h and from day 2 to day 7 following the root canal instrumentation appointment using a VAS and an NRS; the ibuprofen tablets taken and the presence of tenderness on biting were recorded. The instrumentation time was registered. Univariate and multivariate statistics measured the effect of independent variables on the outcomes. Results: From the 75 patients allocated, 8 patients (4 from each group) were lost; in total, 33 patients were analyzed in the PTN group and 34 in the R group. The frequencies of postoperative pain (p > 0.05) and tenderness on biting (p > 0.05) were similar between groups. The medication intake (mean of 1.31 tablets) and the time of instrumentation (approximately 11 min) were similar between groups. Conclusion: ProTaper Next and Reciproc® caused a slight risk of tenderness on biting and contributed to similar self-reported postoperative pain (low intensity) up to 7 days following root canal shaping.

Antimicrobial action of ozonated water and photodynamic therapy with sonic activation in root canals infected with Enterococcus faecalis.

Background: New protocols are constantly being tested in the search for complete disinfection of root canals without the undesirable effects of sodium hypochlorite. This study evaluated the antimicrobial effect of ozonated water and photodynamic therapy (PDT) with sonic activation in root canals infected with Enterococcus faecalis. Material and Methods: Seventy single-rooted canals of human teeth were prepared and contaminated with E. faecalis for 21 days. The teeth were divided into six experimental groups (n=10): ozonized water without (O + S-) and with sonic activation (O + S +); PDT without (PDT + S-) and with sonic activation (PDT + S +); PDT + ozonized water without (PDT + O + S-) and with sonic activation (PDT + O + S +); and two control groups, one positive (n = 5) and one negative (n = 5). Microbial collections were performed before and shortly after treatment, counted in the log of colony-forming units and tested for significant difference between these counts, if any (Student's t-test). The ANOVA two-way test was applied to evaluate whether the Treatment factor (Ozone, PDT and Ozone + PDT) and the Sonic factor (With and without sonic activation) had any effect on microbial reduction. Results: In all protocols, there was a significant microbial reduction (p=0.025), whereas in the groups in which sonic activation was used, the microbial reduction was significantly greater (p=0.001). Conclusions: The treatments significantly reduced the number of microorganisms in the root canals. Sonic activation helped to increase the microbial reduction in infected root canals. Key words:Endodontics, ozone, photodynamic therapy, enterococcus faecalis.

Experimental pastes containing niobophosphate and 45S5 bioactive glasses for treatment of dentin hypersensitivity: dentin permeability and tubule obliteration.

OBJECTIVES: This study tested the ability of bioactive pastes containing niobophosphate and 45S5 glasses to reduce dentin permeability and to obliterate dentinal tubules, as a mean of reducing human dentin hypersensitivity. MATERIALS AND METHODS: Experimental pastes with concentrations of 10, 20, and 30 wt% of two bioactive glasses (45S5 or niobophosphate [NbG]) were formulated. A paste without bioactive glass (placebo) and a commercial paste (Nano P, FGM) were used as controls. Forty dentin disc specimens were obtained from caries-free extracted third human molars and divided in 8 groups (n = 5). Percentage of permeability (%Lp) was assessed in a dental permeability machine considering hydraulic conductance, immediately after pastes application and at day 7, day 14, and day 21. The precipitates formed on the surface of the dentin discs (and dentinal tubules) were analyzed by SEM/EDS and micro-Raman spectra. Data of dentin permeability (%) 2-way repeated-measures (ANOVA) and Holm-Sidak post-tests (α = 0.05). Dentinal tubule obliteration was visually (and elemental) evaluated and descriptively reported. RESULTS: The experimental bioactive glass pastes containing NbG and 45S5, regardless of the concentration, reduced dentin permeability in comparison with pastes without bioactive glasses (P < 0.05). The formulated placebo and commercial paste did not reduce permeability over time (P < 0.05). SEM/EDS and micro-Raman analyses showed that both type of bioactive pastes (NbG or 45S5-based) presented mineral precipitates obliterating the dentinal tubules at day 21. NbG seems to offer a better initial effect than 45S5, while at 21 days there is no difference between both glasses. CONCLUSION: Experimental bioactive pastes containing NbG and 45S5 (at concentrations of 10%, 20%, or 30%) have potential to reduce dentin permeability (over time) in comparison with pastes without bioactive glasses; and this occurs on behalf of obliteration of dentinal tubules by microparticle and precipitate formation. CLINICAL RELEVANCE: Bioactive pastes containing NbG and 45S5 may benefit patients presenting dentin hypersensitivity, because these pastes can start acting fast after application and maintain their action up to 21 days.

Effect of an enamel matrix derivative (Emdogain) on the microhardness and chemical composition of human root dentin: an in vitro study.

The advantage of using an Enamel matrix derivative EMD Emdogain as an intracanal medication could be a manner to strength the tooth structure, improving the physical and chemical properties of dentin. We tested, in vitro, the effect of Emdogain on the surface microhardness and chemical composition of root dentin. Ten human teeth were used to produce dentin specimens originated from the canal walls (n = 30) that remained in contact to Emdogain gel for 90 days. Baseline and 90-days after Emdogain treatment measurements were performed using Fourier Transform Infrared Spectroscopy (ATR/FTIR), Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS) and Knoop indenters. The use of EMD (Emdogain) for 90 days in contact with human root canal dentin specimens did not alter the microhardness and morphology of dentin. The elemental structure of dentin was altered because there was a reduction in carbonate content.

Impact of Immersion Media on Physical Properties and Bioactivity of Epoxy Resin-Based and Bioceramic Endodontic Sealers.

This study assessed the effects of immersion media [distilled water (dw), phosphate buffered saline (pbs) and simulated body fluid (sbf)] in the physical properties [fluid uptake/sorption/solubility and alkalinization activity (pH)] and bioactivity of a bioceramic sealer: the BioRoot RCS (BioRoot) (Septodont). The epoxy-resin sealer AH Plus (Dentsply) was used as comparison. Sealers were immersed in dw, pbs and sbf to evaluate the fluid uptake/sorption/solubility and pH's media. Bioactivity was assessed with SEM/EDS, FTIR-ATR and XRD. BioRoot solubility was as follows: sbf > pbs = dw. BioRoot had alkaline pH, and AH Plus had neutral pH, regardless of the medium. BioRoot presented mineral precipitates and peaks indicating hydroxyapatite-precursors in pbs and sbf. AH Plus physical properties were not affected by immersion media and it had no bioactivity. pbs and sbf should be preferred to investigate bioceramic sealers over distilled water, because they were able to highlight the sealer properties. BioRoot maintained the alkaline environment and favored hard tissue deposition.

Does polishing of bleached enamel affect roughness and tooth color stability after exposure to coffee?

OBJECTIVE: This laboratory randomized study was designed to evaluate the effect of polishing on roughness and color stability of bleached teeth after coffee immersion. MATERIALS AND METHODS: Ninety bovine crowns were randomly allocated to six groups (n = 15), according to bleaching protocols: At-home: standard protocol using 10% hydrogen peroxide (HP) or In-office: standard protocol using 35% HP; and with polishing protocols: (1) no polishing, (2) bleached enamel polished with #0.5 µm or (3) #2-4 µm diamond particles grit pastes. Samples were daily immersed into coffee solution for 45 min followed by mechanical brushing simulation (30 s) for 30 days. The surface roughness (Ra) and color alteration, expressed by ΔEab , ΔE00 , and whitening index (WI) were analyzed at baseline, after bleaching/polishing protocols and after coffee solution staining. The surface from each group was examined using a scanning electron microscope. Data were analyzed by two-way repeated measure analysis of variance followed by the Tukey test (α = 0.05). RESULTS: Staining increases Ra, ΔEab , ΔE00 , and decreases WI values. Polishing after bleaching did not prevent staining, however, tooth polished with #0.5 µ-grit polishing paste showed better performance than #2-4 µ-grit (ΔEab : p = 0.001/ΔE00 : p = 0.003). Scanning electron microscope revealed a more irregular surface after coffee staining for all groups regardless bleaching/polishing protocols. CONCLUSIONS: Using #0.5 µ-grit diamond paste to polish 35%HP in-office bleached enamel reduces the roughness and tooth staining. However, polishing after 10%HP at-home bleached enamel neither affects roughness nor improves tooth color stability after exposure to coffee. CLINICAL SIGNIFICANCE: Polishing after at-home bleaching does not have benefits but after 35% hydrogen peroxide in-office bleaching, the polishing with #0.5 µ-grit polishing paste is indicated to reduce roughness and the tooth staining over time.

Synthesis and characterization of experimental endodontic sealers containing bioactive glasses particles of NbG or 45S5.

OBJECTIVE: This study evaluated the influence of adding bioactive glasses particles [Niobophosphate (NbG) or bioglass (45S5)] into endodontic cements in relation to physical, chemical and biological properties. METHODS: The following commercial cements were used as comparison: AH Plus (Dentsply), Endofill (Dentsply), MTA Fillapex (Angelus) and EndoSequence (BC Sealer, Brasseler). Setting time, radiopacity, flow rate, weight loss/variation, alkaline capacity (pH) at different time-intervals (24h/48h/7d/14d/28d), bioactivity (assessed under SEM/EDS, FTIR/ATR and XDR) and cell viability were measured. Data were analyzed by One-way ANOVA/Holm-Sidak post-test (α = 5%) (normal distribution) and Kruskal-Wallis/Students-Newman-Keuls post-test (α = 5%) (non-normal distribution). RESULTS: Bioactive endodontic experimental cements (containing NbG or 45S5) had high alkalinization capacity. The experimental cements presented high weight loss/variation (p < 0.001). 45S5 experimental cement did not present radiopacity (p < 0.001). AH Plus had the lowest cell cytotoxicity when compared to the other tested cements (p < 0.001). Regarding bioactivity, SEM/EDS analyses showed precipitates with high concentrations of Ca/P for 45S5 and NbG, as well as for MTA Fillapex and BC Sealer. AH plus and Endofill did not present bioactive precipitates. FTIR/ATR and XDR analyses found hydroxyapatite precursors for NbG, 45S5, MTA Fillapex and BC Sealer. SIGNIFICANCE: The incorporation of bioactive particles (NbG or 45S5) into endodontic cements had potential to neutralize acidic environments and induced formation of hydroxyapatite precursors. Clinically, these would produce a cement that is bactericidal and have the potential to improve tissue healing. The improved radiopacity and flowability would facilitate the visualization of the material in the radiograph and the filling of anatomical complexities during root canal obturation. As drawbacks, the excessive weight loss and post-setting cytotoxicity could result in clinical degradation of the cement and adjacent tissue irritation for the patient.

Ex vivo evaluation of the effectiveness of XP-endo Finisher on the removal of smear layer from the root canal / Avaliação ex vivo da eficácia do XP-endo Finisher na remoção de smear layer do canal radicular

ABSTRACT Objective: The aim of this study was to evaluate the effectiveness of XP-endo Finisher (XP) on removal of the smear layer in root canals by comparing different irrigation protocols. Methods: Seventy-two human single-rooted teeth were similarly instrumented using R25 Reciproc files (VDW, Munich, Germany) applied in reciprocating mode with a VDW GOLD endo motor (VDW, Munich, Germany). The working length was determined at 1 mm short of the apical foramen. The canals were irrigated with 5 mL of 2.5% sodium hypochlorite during instrumentation. The teeth were divided at random into six groups (n=12). A control group, which was not submitted to the final irrigation protocol, and five experimental groups with different irrigants and agitation techniques: EDTA/File, EDTA/XP, EDTA/Passive Ultrasonic Irrigation (PUI), Distilled Water (DW)/XP, and DW/PUI). Smear layer removal quality scores were assessed in the apical, middle, and cervical thirds of the root canal based on images obtained by scanning electron microscopy. Data were analyzed using the Kruskal-Wallis test, followed by two-by-two comparisons with the Dunn test (α=5%). Results: EDTA/File, EDTA/PUI, and EDTA/XP groups demonstrated significantly lower scores than the other groups (P<0.05) in all thirds evaluated. No significant difference was observed between the groups in which distilled water was used and the control group in all thirds evaluated (P> 0.05). Conclusion: The XP-endo Finisher file did not increase the efficiency of EDTA in removal of the smear layer in root canals.

RESUMO Objective: Avaliar a eficácia do XP-endo Finisher (XP) na remoção da smear layer em canais radiculares, comparando diferentes protocolos de irrigação. Métodos: Setenta e dois dentes humanos unirradiculares foram similarmente instrumentados usando limas R25 (VDW, Munich, Germany) aplicadas no modo reciprocrantes em um motor endodôntico VDW GOLD (VDW, Munich, Germany). O comprimento de trabalho foi determinado a 1 mm aquém do forame apical. Os canais foram irrigados com 5 mL de hipoclorito de sódio 2,5% durante a instrumentação. Os dentes foram divididos aleatoriamente em seis grupos (n=12). Um grupo controle, que não foi submetido ao protocolo final de irrigação, e cinco grupos experimentais com diferentes irrigantes e técnicas de agitação: EDTA/Lima, EDTA/XP, EDTA/Irrigação Ultrassônica Passiva (IUP), Água destilada (AD)/XP, e AD/IUP). Os escores de qualidade de remoção da camada de smear layer foram avaliados nos terços apical, médio e cervical do canal radicular com base em imagens obtidas por microscopia eletrônica de varredura. Os dados foram analisados pelo teste de Kruskal-Wallis, seguido de comparações dois a dois pelo teste de Dunn (α = 5%). Resultados: Os grupos EDTA/lima, EDTA/PUI e EDTA/XP demonstraram escores significativamente menores que os outros grupos (P <0,05). Não foi observada diferença entre os grupos que utilizaram água destilada e o grupo controle em todos os terços avaliados (P> 0.05). Conclusão: A lima XP-endo Finisher não aumentou a eficiência do EDTA na remoção da smear layer em canais radiculares.

Development and characterization of experimental ZnO cement containing niobophosphate bioactive glass as filling temporary material.

AIMS: The aim of this study was to develop and characterize a temporary restorative material based on a zinc oxide matrix containing niobophosphate bioactive glass (NbG) for the caries-affected dentin treatment. MATERIAL AND METHODS: NbG was added to a ZnO2 matrix in different concentrations (wt%). EDS-SEM, ATR-FTIR and XRD analyses were performed to characterize the cement. Calcium release was evaluated in TRIS solution after 1, 7 and 14 days by colorimetric method (A650). Compressive strengths and setting times were performed to analyze mechanical properties. RESULTS: EDS spectra confirmed the presence of Ca, P and Nb in the groups containing NbG. EDS mapping exhibit the ZnO2 homogeneous distribution, and NbG immersed in this matrix. Peaks suggesting interaction between matrix and NbG were not detected in Ftir spectra. Calcium releasing showed to be time-dependent for experimental groups containing 10, 20, 30 and 40%. The NbG incorporation progressively increased the compressive strength values in the experimental groups. NbG incorporation seemed to influence the ZnO2 matrix early setting reaction. No statistical difference was observed in the final setting time. CONCLUSION: The addition of NbG particles into zinc oxide matrix could work as a mechanical reinforcement. It is suggested that the calcium released by the cement containing at least 10% NbG could induce apatite formation.

Development and characterization of self-etching adhesives doped with 45S5 and niobophosphate bioactive glasses: Physicochemical, mechanical, bioactivity and interface properties.

OBJECTIVE: The aim of study was to develop and characterize experimental bioactive glasses (45S5 and niobophosphate bioactive glass (NbG)) and evaluate the effects of their addition in self-etching adhesive systems on physicochemical, mechanical, and bioactive properties, microtensile bond strength (µTBS), and nanoleakage (NL). METHODS: Two-step self-etching adhesive systems containing 5, 10, and 20 wt.% of 45S5 and NbG bioactive glasses were developed. An experimental adhesive without microparticles and a commercial adhesive (Clearfil SE Bond) were used as control groups. The materials were evaluated for their degree of conversion (DC%), ultimate tensile strength (UTS), softening in solvent, radiopacity, sorption and solubility, alkalizing activity (pH), ionic release, and bioactivity. µTBS and NL were evaluated after 24 h and 1 year of storage. The data were subjected to analysis of variance and post-Holm-Sidak tests (α = 0.05). RESULTS: The addition of the two bioactive glasses did not change the values of the degree of conversion, ultimate tensile strength, and softening in solvent. The adhesive system containing 20% NbG showed the highest radiopacity. The incorporation of 45S5 increased water sorption and solubility, raised the pH, and allowed the release of large amounts of calcium. After 28 days of immersion in simulated body fluid, the 45S5 adhesive precipitated hydroxyapatite and calcium carbonate (SEM/EDX, ATR/FTIR, and XDR). The addition of 45S5 and NbG to the adhesives improved the stability of the resin-dentin interface after 1 year. SIGNIFICANCE: The incorporation of microparticles from 45S5 bioactive glass in self-etching adhesive systems is considered an excellent alternative for the development of a bioactive adhesive that improves the integrity of the hybrid layer on sound dentin.