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1.
Biosci. j. (Online) ; 36(5): 1785-1793, 01-09-2020. tab, ilus
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1147935

RESUMO

This study objectives to evaluate the fracture strength of upper central incisors (UCI) restored with composite resin (CR) in Class III cavities and endodontically treated teeth with or without glass fiber post (GFP), analyzing their failure mode. Sixty human UCI were randomly divided into four experimental groups: endodontically treated teeth without GFP (G1), endodontically treated teeth with GFP (G2), teeth with mesial/distal Class III cavities restored with CR without GFP (G3), and teeth with mesial/distal Class III cavities restored with CR with GFP (G4). The samples were submitted to the fracture strength test in a universal testing machine with a compression shear load applied at speed of 1.0 mm/min until fracture occurred. The data were submitted to one-way ANOVA (α=0.05) and the samples were analyzed for failure mode. The analysis did not show a significant statistical difference in fracture strength between the groups (p>0.05). The results showed that only endodontically treated teeth (G1) (753.4N) presented behavior similar to teeth with GFP (G2) (702.1N). The same occurred when comparing teeth with Class III cavities without GFP (G3) (670.2 N) and with GFP (G4) (746.1N). It can be concluded that glass fiber posts do not change the fracture strength of incisors with endodontic treatment and Class III cavities. KEYWORDS: Cavities. Composite resins. Endodontically treated teeth. Fracture. INTRODUCTION Endodontically treated teeth with little remaining crown structure are considered more fragile than healthy teeth due to the loss of healthy dental structure (KARZOUN et al., 2015). In such cases, the use of an intraradicular post is indicated to promote retention to the future restoration. For many years, the cast metal cores (CMC) and the intraradicular metal posts were the only form of tooth retention (SMITH et al., 1998). However, research indicates that such posts may cause irreparable fractures (BARCELLOS et al., 2013; GUO et al., 2016), for requiring the wear of the dentin structure (CHUANG et al., 2010) and for presenting both a high modulus of elasticity (SANTOS-FILHO et al., 2008; FARINA et al., 2015) and the possibility of corrosion (LASSILA et al., 2004)thus limiting their use. Glass fiber posts (GFP) have advantages over metal posts because they provide better aestheticsand dentin-like biomechanical properties (GORACCI et al., 2007; MARTELLI et al., 2008; SANTOS-FILHO et al., 2008; MOSHARRAF et al., 2012; AMARNATH et al., 2015). Their retention is related to specific characteristics such as post length, type of cement used, and amount of remaining tooth structure (ALOMARI et al., 2011; MAKADE et al., 2011; INAGAKI et al., 2014; KHOROUSHI et al., 2016). It is also known that the clinical applicability of GFP is directly related to the reconstruction of the dental element lost (MAKADE et al., 2011; AMBICA et al., 2013; WANDSCHER et al., 2014; REZAEI et al., 2015; RAHMAN et al., 2016). Thus, an intraradicular post should be selected with caution, verifying the amount of remaining tooth structure, root canal anatomy, post length and diameter, as well as the physical properties and modulus of elasticity (ALOMARI et al., 2011; HATTA et al., 2011; LE BELL-RÖNNLÖF et al., 2011). The higher the amount of remaining crown, the higher the resistance of the dental element (ZOGHEIB et al., 2008; Received: 02/06/19 Accepted: 30/12/19


Este estudo objetiva avaliar a resistência à fratura de incisivos centrais superiores (ICS) restaurados com resina composta (RC) em cavidades Classe III e dentes tratados endodonticamente com ou sem pino de fibra de vidro (PFV), analisando seu padrão de fratura. Sessenta ICS humanos foram divididos aleatoriamente em quatro grupos experimentais: dentes tratados endodonticamente sem PFV (G1), dentes tratados endodonticamente com PFV (G2), dentes com cavidades mesiais/distais Classe III restauradas com RC sem PFV (G3), e dentes com cavidades mesiais/distais Classe III restauradas com RC com PFV (G4). As amostras foram submetidas ao teste de resistência à fratura em uma máquina universal de ensaios com uma carga de cisalhamento de compressão aplicada na velocidade de 1,0 mm / min até a ocorrência da fratura. Os dados foram submetidos à ANOVA unidirecional (α=0,05) e as amostras foram analisadas quanto ao modo de falha. A análise não mostrou diferença estatisticamente significativa na resistência à fratura entre os grupos (p>0,05). Os resultados mostraram que os dentes apenas tratados endodonticamente (G1) (753,4N) apresentaram comportamento semelhante aos dentes com PFV (G2) (702,1N). O mesmo ocorreu ao comparar dentes com cavidades Classe III sem PFV (G3) (670.2 N) e com PFV (G4) (746.1N). Pode-se concluir que pinos de fibra de vidro não alteram a resistência à fratura de incisivos com tratamento endodôntico e cavidades Classe III.

2.
Dent Mater ; 36(10): e302-e308, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32811665

RESUMO

OBJECTIVES: To investigate the role of proteoglycans (PGs) on the physical properties of the dentin matrix and the bond strength of methacrylate resins with varying hydrophilicities. METHODS: Dentin were obtained from crowns of human molars. Enzymatic removal of PGs followed a standard protocol using 1 mg/mL trypsin (Try) for 24 h. Controls were incubated in ammonium bicarbonate buffer. Removal of PGs was assessed by visualization of glycosaminoglycan chains (GAGs) in dentin under transmission electron microscopy (TEM). The dentin matrix swelling ratio was estimated using fully demineralized dentin. Dentin wettability was assessed on wet, dry and re-wetted dentin surfaces through water contact angle measurements. Microtensile bond strength test (TBS) was performed with experimental adhesives containing 6% HEMA (H6) and 18% HEMA (H18) and a commercial dental adhesive. Data were statistically analyzed using ANOVA and post-hoc tests (α = 0.05). RESULTS: The enzymatic removal of PGs was confirmed by the absence and fragmentation of GAGs. There was statistically significant difference between the swelling ratio of Try-treated and control dentin (p < 0.001). Significantly lower contact angle was found for Try-treated on wet and dry dentin (p < 0.002). The contact angle on re-wet dentin was not recovered in Try-treated group (p = 0.9). Removal of PGs significantly improved the TBS of H6 (109% higher, p < 0.001) and H18 (29% higher, p = 0.002) when compared to control. The TBS of commercial adhesive was not affected by trypsin treatment (p = 0.9). SIGNIFICANCE: Changing the surface energy of dentin by PGs removal improved resin adhesion, likely due to more efficient water displacement, aiding to improved resin infiltration and polymerization.

3.
Sci Rep ; 10(1): 7313, 2020 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-32355304

RESUMO

The objective of this study was to evaluate the effects of glycolic acid (GA) (with pH 1.2 and 5) and ethylenediaminetetraacetic acid (EDTA) on the chemical and mechanical properties of dentin to investigate the potential use of GA as final irrigant in the root canal therapy. Specifically, changes in microhardness, smear layer removal, erosion, mineral content distribution, apatite/collagen ratio and flexural strength of mineralized dentin treated with GA were assessed. Saline solution was used as a negative control. Knoop microhardness (KHN) was measured on the root canal lumen of root segments. Dentin beams were used for 3-point flexural strength (σ) test. Scanning electron microscopy (SEM) images of root sections were obtained for evaluation of smear layer removal and dentin erosion on root segments and energy dispersive X-ray spectroscopy (EDS) was used for mineral content distribution. The apatite/collagen ratio (A/C) in dentin powder were examined by Fourier transform infrared (FTIR) spectroscopy. KHN, σ and A/C results were statistically analyzed with ANOVA and Tukey tests (α = 0.05). Smear layer and dentin erosion scores were analyzed with Kruskal-Wallis and Dunn tests (α = 0.05). Root dentin treated with EDTA and GA presented similar KHN regardless of the pH (p > 0.05). However, KHN was significantly reduced in EDTA and GA groups when compared to control group (p<0.001). GA showed the same ability to remove the smear layer and to cause dentin erosion as EDTA. EDS results showed that the GA and EDTA solutions did not alter the dentin mineral content distribution. The apatite/collagen ratio reduced with all irrigant solution and was the lowest with GA pH 5 (p<0.001), while σ was not significantly affected by the experimental solutions (p = 0.559). It can be concluded that GA has similar ability to remove the smear layer than EDTA. GA does not affect negatively the chemical/mechanical properties and it does not increase dentin erosion. The use of GA with low pH seems to promote less change in collagen/apatite ratio, but further studies are needed to establish an ideal clinical protocol. Therefore, this study supports the potential use of GA as an alternative final irrigation solution for root canal preparation.

4.
Eur Endod J ; 5(1): 35-39, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32342036

RESUMO

Objective: The purpose of this research was to compare relative effectiveness of sodium hypochlorite 5.25% (NaOCl), 2% chlorhexidine gel (CHX) and 6.5 % grape seed extract (GSE) against Enterococcus faecalis using instrument Reciproc R25 in root canal preparation. Methods: Forty-five mesiobuccal root canals from extracted human maxillary molars were collected and infected with Enterococcus faecalis. The samples were divided into five groups according to the different types of irrigants: saline (positive control) (n=5); in the other groups were used 10 root canals for each group: NaOCl+EDTA; CHX gel+EDTA; GSE solution+EDTA; GSE gel+EDTA. All the groups were prepared with reciprocating instruments Reciproc R25. Bacterial reduction was measured by two-way ANOVA (P<0.001) followed by Tukey HSD post-hoc tests, from the counting of colony forming units (CFUs) from samples collected before instrumentation and after. The significance level established at 5% (P<0.05). Results: The group prepared with the NaOCl resulted in highest antimicrobial capacity among of all (P>0.05), followed by CHX and GSE gel (P<0.05). Control and GSE solution showed similar results (P<0.05) and resulted in the lowest percentage of the reduction of the microorganism into the root canals. Conclusion: NaOCl had the higher elimination capacity of Enterococcus faecalis than GSE and CHX.

5.
Gen Dent ; 68(1): 41-44, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31859661

RESUMO

The objective of this study was to evaluate the antimicrobial capacity of glycolic acid (GA) at different concentrations as a final irrigant during the preparation of root canals. The sample consisted of 77 extracted single-rooted human teeth with complete root formation, no previous endodontic treatment, and a root length of at least 14 mm. The root canals were prepared in a standardized manner with a rotary file system. During this process, irrigation was performed with 2.5% sodium hypochlorite (NaOCl), and the final irrigant was 17% ethylenediaminetetraacetic acid (EDTA). After the root canal sterilization procedure, Enterococcus faecalis was cultured in a Petri dish, and 70 sterilized root canals were inoculated with a suspension containing 3.0 × 108 colony-forming units (CFUs) per milliliter. The roots were divided into 7 groups (n = 10) according to the following solutions: 0.9% sodium chloride (NaCl); 6% NaOCl; 17% EDTA; 10%, 17%, or 25% GA; or 17% citric acid (CA). The capacity of the different substances to reduce E faecalis was evaluated by counting the CFUs before and after treatment with the final irrigant solutions. Data were subjected to an analysis of variance and the Tukey test at a 5% significance level. The greatest bacterial reduction was observed in the group irrigated with NaOCl (P < 0.05). There were no statistically significant differences among the groups irrigated with GA in different concentrations (P > 0.05), but they all demonstrated greater disinfection capacity than CA and EDTA (P < 0.05). CA showed significantly greater antimicrobial capacity than EDTA (P < 0.05). EDTA showed significantly greater antimicrobial capacity only in relation to NaCl (P < 0.05). At different concentrations, GA demonstrated greater capacity to eliminate E faecalis from root canals than did EDTA.


Assuntos
Anti-Infecciosos , Glicolatos , Irrigantes do Canal Radicular , Preparo de Canal Radicular , Anti-Infecciosos/farmacologia , Cavidade Pulpar , Ácido Edético , Enterococcus faecalis , Glicolatos/farmacologia , Humanos , Preparo de Canal Radicular/métodos , Hipoclorito de Sódio
6.
Photodiagnosis Photodyn Ther ; 29: 101625, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31866534

RESUMO

INTRODUCTION: This study aimed to evaluate the antimicrobial action of calcium hypochlorite(Ca[OCl]2) and sodium hypochlorite (NaOCl) with reciprocating instrumentation and photodynamic therapy(PDT), and its influence on root dentin structure. METHODS: One hundred and ten human teeth were used to antimicrobial evaluation, inoculated with Enterococcus faecalis and divided into 11 groups (n = 10): G1 - distilled water(control); G2-1 % NaOCl; G3-5.25 % NaOCl; G4-1 % Ca(OCl)2; G5-5.25 % Ca(OCl)2; G6-PDT; G7-distilled water + PDT; G8-1 % NaOCl + PDT; G9-5.25 % NaOCl + PDT; G10-1 % Ca(OCl)2+PDT; G11-5.25 % Ca(OCl)2+PDT. In all groups, except G6, the root canals were instrumented with #R50 Reciproc file in the working length in association with tested chemical auxiliary substance. The counting of colony forming units (CFUs) was performed to calculate the bacterial percentage reduction of each group. Following, 55 bovine teeth were used to microhardness evaluation and divided into the same 11 groups (n = 5), with no instrumentation and immersion in the tested protocols. The modification of root dentin microhardness was evaluated by using the Vicker tester. Finally, 33 bovine teeth were used to organic components evaluation and divided into the same 11 groups (n = 3), with no instrumentation and immersion in the tested protocols. The modification of organic components of root dentin was evaluated by light microscopy. Specific statistical analysis was performed for each evaluation. RESULTS: The higher bacterial reduction was observed in groups 3,4,5,8,9,10 and 11, with no statistical difference between them (p > 0.05). The higher microhardness reduction was observed in groups 8,9,10 e 11, with no statistical difference between them (p > 0.05). The highest modification on organic components was observed in groups 3,5,9 and 11, with no statistical difference between them (p > 0.05). CONCLUSIONS: The association of Ca(OCl)2, reciprocating instrumentation and PDT promotes effective antimicrobial action. Moreover, lower modification was induced in microhardness and organic components of root dentin, by using Ca(OCl)2 in low concentration associated to PDT.

7.
Mater Sci Eng C Mater Biol Appl ; 106: 110283, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31753393

RESUMO

The aim of this study was to characterize glycolic acid (GA) and examine its effects on powder and flexural strength of dentin. Particle size and energy-dispersive EDS in GA powder was performed for chemical analysis. Surface tension and pH levels of ethylenediaminetetraacetic acid (EDTA), citric acid (CA), and GA solutions were evaluated at different times and temperatures. Dentin powder and mineralized dentin beams were immersed for 1 min in EDTA, CA, or GA solutions and subjected to Fourier transform infrared spectroscopy for apatite/collagen ratio analysis and 3-point flexure test, respectively. GA showed the largest particle size (µm), and its surface tension was similar to that of EDTA and CA. Surface tension decreased in solutions of higher concentrations. GA showed pH stability at all times and temperatures evaluated. The apatite/collagen ratio reduced with increased GA concentrations, while flexural strength was not significantly affected by GA concentration. GA seems a good choice as a final irrigation solution after root canal preparation.


Assuntos
Dentina/química , Glicolatos/química , Ácido Cítrico/química , Colágeno/química , Colágeno/metabolismo , Cavidade Pulpar/efeitos dos fármacos , Dentina/efeitos dos fármacos , Ácido Edético/química , Resistência à Flexão , Glicolatos/farmacologia , Humanos , Concentração de Íons de Hidrogênio , Tamanho da Partícula , Desnaturação Proteica , Irrigantes do Canal Radicular/química , Irrigantes do Canal Radicular/farmacologia , Tensão Superficial , Temperatura
8.
Mater Sci Eng C Mater Biol Appl ; 100: 323-329, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30948068

RESUMO

The aim of this study was to investigate the effects of glycolic acid (GA) on the microhardness, roughness, dentin mineral content distribution; smear layer removal and cytotoxicity. One hundred human teeth were randomly divided into six groups: distilled water (control group), 17% EDTA, 10% citric acid (CA), 5% GA, 10% GA, and, 17% GA. Microhardness and roughness were measured in the canal lumen. Scanning electron microscopy (SEM) images (2000×) for smear layer removal evaluation; energy dispersive X-ray spectroscopy (EDS) for chemical analysis. Cell viability assay was made on fibroblast cells. The lowest microhardness and higher roughness were observed for 17% GA. GA showed the ability to remove the smear layer to a similar level as EDTA and CA, with no statistical difference between the concentrations used. GA and CA were cytotoxic in a dose-dependent manner. GA showed potential as an endodontic agent for final irrigation in root canal terapies.


Assuntos
Endodontia , Glicolatos/farmacologia , Fenômenos Mecânicos , Irrigantes do Canal Radicular/farmacologia , Células 3T3 , Animais , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Dureza , Humanos , Camundongos , Camada de Esfregaço/patologia
9.
Odontology ; 107(3): 316-323, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30710179

RESUMO

Proteoglycans are biomacromolecules with significant biomineralization and structural roles in the dentin extracellular matrix. This study comprehensively assessed the mechanical properties and morphology of the dentin extracellular matrix following chemical removal of proteoglycans to elucidate the structural roles of proteoglycans in dentin. Dentin extracellular matrix was prepared from extracted teeth after complete tissue demineralization. Chemical removal of proteoglycans was carried-out using guanidine hydrochloride for up to 10 days. The removal of proteoglycans was determined by dimethylmethylene blue colorimetric assay and histological staining analyses using transmission electron microscopy and optical microscopy. The modulus of elasticity of dentin matrix was determined by a 3-point bending test method. Partial removal of proteoglycans induced significant modifications to the dentin matrix, particularly to type I collagen. Removal of proteoglycans significantly decreased the modulus of elasticity of dentin extracellular matrix (p < 0.0001). In conclusion, the subtle disruption of proteoglycans induces pronounced changes to the collagen network packing and the bulk modulus of elasticity of dentin matrix.


Assuntos
Dentina , Proteoglicanas , Colágeno Tipo I , Matriz Extracelular , Microscopia Eletrônica de Transmissão
10.
Biomed Res Int ; 2019: 2196519, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30719440

RESUMO

Objectives: The aim of this study was to evaluate the influence of ferule and the post type on the fracture strength and stress distribution in premolars. Materials and Methods: Forty human mandibular premolars were decoronated, allocated in four groups, and restored as follows: CPC-NF: cast post-and-core and absence of ferule; CPC-F: cast post-and-core and presence of ferule; FPC-NF: glass-fiber posts and absence of ferule; FPC-F: glass-fiber posts and presence of ferule. The fracture strength (FS) and failure patterns were evaluated. Finite element analysis (FEA) evaluated the stress distribution. Results: FS did not differ between CPCs and FPC either in presence or in absence of ferule. The presence of ferule increased FS with both post types. Mean values of FS for ferule groups were higher than functional or parafunctional loads reported in literature, which was not the case for FPC-NF when compared to parafunctional loads. FEA with a functional load showed slightly higher compressive stresses in dentin in the group CPC-NF, which was much lower than the compressive strength of dentin. Lower percentage of catastrophic failures was observed in nonferule groups irrespective of post type, which was explained by the stress concentration in the cervical root region when FEA with the FS load was simulated. Conclusion: Ferule effect was shown to be more important than post type in the analysis. Both posts showed potential to withstand functional loads irrespective of presence of ferule. However, the mean FS was lower than parafunctional loads for FPC in the absence of ferule.


Assuntos
Força Compressiva/fisiologia , Resistência à Flexão/fisiologia , Vidro/química , Fraturas dos Dentes/fisiopatologia , Dente Pré-Molar/fisiopatologia , Resinas Compostas/química , Materiais Dentários/química , Falha de Restauração Dentária , Análise do Estresse Dentário/métodos , Análise de Elementos Finitos , Humanos , Teste de Materiais/métodos , Cimentos de Resina/química , Estresse Mecânico
11.
Braz Dent J ; 29(5): 459-464, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30517444

RESUMO

The aim of this study was to compare the efficacy of grape seed extract (GSE), calcium hypochlorite [Ca(ClO)2], and sodium hypochlorite (NaOCl) irrigant solutions with rotary or reciprocating instrumentation for disinfection of root canals inoculated with Enterococcus faecalis. The mesiobuccal root canals of mandibular molars were prepared and inoculated with Enterococcus faecalis for 21 days. The roots were then randomly divided into the following eight experimental groups (n=11) according to the instrumentation technique and disinfection protocol: ProTaper Next or Reciproc R25 with sodium chloride (control group), 6% NaOCl, 6% Ca(ClO)2, or 50% GSE used for irrigation during instrumentation. The antimicrobial activity was determined on the basis of a reduction in colony-forming units (CFUs) counted on bacterial samples collected before and after root canal instrumentation and expressed as a percentage of reduction. Data were evaluated by two-way ANOVA followed by Tukey HSD post-hoc tests (p<0.05). No significant differences were observed in bacterial reduction between the ProTaper Next and Reciproc R25 systems (p>0.05), regardless of the irrigant solution used. Furthermore, all active solutions (6% NaOCl, 50% GSE, and 6% Ca(ClO)2) showed similar potential to reduce bacterial counts (p>0.05) and were significantly more effective than sodium chloride (control) (p<0.05). The results suggest that the GSE and Ca(ClO)2 have potential clinical application as irrigant solutions in endodontic therapy since they present bactericidal efficacy against Enterococcus faecalis.


Assuntos
Antibacterianos/farmacologia , Desinfecção/métodos , Enterococcus faecalis/efeitos dos fármacos , Irrigantes do Canal Radicular/farmacologia , Compostos de Cálcio/farmacologia , Resinas Compostas/química , Instrumentos Odontológicos , Cavidade Pulpar/microbiologia , Extrato de Sementes de Uva/farmacologia , Humanos , Técnicas In Vitro , Dente Molar , Hipoclorito de Sódio/farmacologia , Células-Tronco
12.
J Adhes Dent ; 20(4): 365-369, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30206579

RESUMO

PURPOSE: To evaluate the efficacy of natural collagen crosslinkers on compromised adhesive bond strength to NaOCl-treated pulp chamber dentin. MATERIALS AND METHODS: Mesial surfaces of the pulp chamber dentin of 120 extracted human molars were obtained. The dentin fragments were divided into six groups according to the protocols used: no treatment (negative control), sodium hypochlorite (NaOCl) for 30 min and final irrigation with 17% EDTA for 3 min (positive control). After treatment with NaOCl and EDTA, the dentin surfaces of the experimental groups were treated for 5 min with one of the following: grape seed extract (GSE), tannic acid (TA), green tea (GT), or n-acetyl cysteine (NAC). Half of the samples of each group were bonded with an etch-and-rinse (Single Bond; 3M Oral Care) and the other half using a self-etch (Scotchbond Universal; 3M Oral Care) adhesive. The restoration was completed with composite. The bonded specimens were sectioned to produce sticks and subjected to the microtensile bond strength test. Data were analyzed by two-way ANOVA and Tukey's HSD test (p < 0.05). RESULTS: Both adhesives had similar bond strengths (p > 0.05). The NaOCl-treated group had significantly lower bond strength than the negative control (p < 0.05). The application of NAC did not recover compromised bonding (p > 0.05). On the other hand, GSE, TA and GT had significant reversal effects of the bond strengths to NaOCl-treated dentin (p < 0.05). CONCLUSION: Compromised bonding of adhesives to NaOCl-treated dentin can be reversed by the application of either GSE, TA or GT.


Assuntos
Colágeno , Cavidade Pulpar , Adesivos Dentinários , Colagem Dentária , Cimentos Dentários , Dentina , Humanos , Teste de Materiais , Cimentos de Resina , Irrigantes do Canal Radicular , Resistência à Tração
13.
Braz. dent. j ; 29(5): 459-464, Sept.-Oct. 2018. tab
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-974175

RESUMO

Abstract The aim of this study was to compare the efficacy of grape seed extract (GSE), calcium hypochlorite [Ca(ClO)2], and sodium hypochlorite (NaOCl) irrigant solutions with rotary or reciprocating instrumentation for disinfection of root canals inoculated with Enterococcus faecalis. The mesiobuccal root canals of mandibular molars were prepared and inoculated with Enterococcus faecalis for 21 days. The roots were then randomly divided into the following eight experimental groups (n=11) according to the instrumentation technique and disinfection protocol: ProTaper Next or Reciproc R25 with sodium chloride (control group), 6% NaOCl, 6% Ca(ClO)2, or 50% GSE used for irrigation during instrumentation. The antimicrobial activity was determined on the basis of a reduction in colony-forming units (CFUs) counted on bacterial samples collected before and after root canal instrumentation and expressed as a percentage of reduction. Data were evaluated by two-way ANOVA followed by Tukey HSD post-hoc tests (p<0.05). No significant differences were observed in bacterial reduction between the ProTaper Next and Reciproc R25 systems (p>0.05), regardless of the irrigant solution used. Furthermore, all active solutions (6% NaOCl, 50% GSE, and 6% Ca(ClO)2) showed similar potential to reduce bacterial counts (p>0.05) and were significantly more effective than sodium chloride (control) (p<0.05). The results suggest that the GSE and Ca(ClO)2 have potential clinical application as irrigant solutions in endodontic therapy since they present bactericidal efficacy against Enterococcus faecalis.


Resumo O objetivo deste estudo foi comparar a eficácia do extrato de semente de uva (ESU), hipoclorito de cálcio [Ca(ClO)2] e hipoclorito de sódio (NaOCl) como soluções irrigadores quando utilizadas com instrumentos reciprocantes e rotatórios para desinfecção de canais radiculares infectados com Enterococcus faecalis. Raízes mesio-vestibulares de molares inferiores foram preparados e inoculados com E. faecalis por 21 dias. As raízes foram aleatoriamente divididas em 8 grupos (n=11) de acordo com a técnica de instrumentação e protocolo de irrigação: ProTaper Next ou Reciproc R25 associados com soro fisiológico (grupo controle), Ca(ClO)2 6%, NaOCl 6% ou ESU 50%. A atividade antimicrobiana foi determinada pela redução do número de Unidades Formadoras de Colonias (UFCs) coletadas antes e após a instrumentação e expressas em porcentagens de redução. Os dados foram analisados estatisticamente pelos testes ANOVA seguido pelo teste complementar de Tukey HSD (p<0,05). Não foi encontrado diferença estatisticamente significante na redução bacteriana entre os sistemas ProTaper Next e Reciproc R25 (p>0.05), independente da solução irrigadora usada. Além disso, todas as soluções ativas (NaOCl, ESU e Ca(ClO)2) mostraram similar potencial em reduzir a quantidade de bactérias (p>0.05) e foram significativamente mais efetivas que o soro fisiológico (p<0.05). Pode-se concluir que o ESU e o Ca(ClO)2 apresentam potencial para aplicação clínica como irrigantes endodônticos uma vez que apresentaram efetividade antimicrobiana contra o E. faecalis.

14.
J Conserv Dent ; 21(3): 269-273, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29899628

RESUMO

Aim: The aim of this study was to compare the bacterial reduction achieved with reciprocating instruments such as Reciproc® R25 (VDW GMBH, Munich, Germany) and Reciproc® R25 combined with rotary file Mtwo 40.04 (VDW GMBH) during root canal preparation. Materials and Methods: Fifty mesiobuccal root canals of maxillary molars were contaminated with Enterococcus faecalis broth culture and then an initial bacterial sample was collected from the root canal with paper cones and plated on brain-heart infusion agar. The root canals were divided into four groups as follows: Reciproc® R25 (n = 20) and Reciproc® R25 combined with Mtwo 40.04 instrument (n = 20). The negative controls consisted of five uncontaminated root canals and the positive control consisted of five contaminated roots that were not subjected to any decontamination procedure. Irrigation was performed using sodium chloride. After instrumentation, samples were collected with paper cones and the rate of bacterial reduction was calculated. Microbiological testing (colony-forming units [CFUs]) was performed to quantify the decontamination obtained by the proposed protocols. Statistical analysis was performed by paired t-test and analysis of variance test. Results: Both techniques significantly reduced the number of bacteria in the root canal (P < 0.05), with no significant difference among them (P > 0.05). Conclusion: The addition of the instrument Mtwo 40.04 after the root preparation with the instrument R25 does not improve its decontamination capability.

15.
Arch Oral Biol ; 82: 203-208, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28651092

RESUMO

OBJECTIVE: Proteoglycans (PGs) are multifunctional biomacromolecules of the extracellular matrix of collagen-based tissues. In teeth, besides a pivotal regulatory role on dentin biomineralization, PGs provide mechanical support to the mineralized tissue and compressive strength to the biosystem. This study assessed enzymatic protocols for selective PGs removal from demineralized dentin to determine the roles of these biomacromolecules in the bulk mechanical properties and biostability of type I collagen. METHODS: Selective removal of glycosaminoglycans chains (GAGs) and PGs from demineralized dentin was carried out by enzymatic digestion protocols using chondroitinase ABC (c-ABC) and trypsin (Try). A comprehensive study design included assessment of dentin matrix mass loss, biodegradability of the PGs/GAGs-depleted dentin matrix, ultimate tensile strength (UTS) and energy to fracture tests. Quantitative data was statistically analyzed by two-way and one-way ANOVA followed by the appropriate post hoc tests (α=0.05). RESULTS: Transmission electron microscopy images show effective GAGs removal by c-ABC and Try and both enzymatic methods released statistically similar amounts of GAGs from the demineralized dentin. Try digestion resulted in about 25% dentin matrix mass loss and increased susceptibility to collagenolytic digestion when compared to c-ABC (p=0.0224) and control (p=0.0901). Moreover, PGs digestion by Try decreased the tensile strengths of dentin. Statistically lower energy to fracture was observed in c-ABC-treated dentin matrix. CONCLUSIONS: GAGs plays a pivotal role on tissue mechanics and anisotropy, while the core protein of PGs have a protective role on matrix biostability.


Assuntos
Dentina/química , Proteoglicanas/fisiologia , Anisotropia , Fenômenos Biomecânicos , Colágeno Tipo I/metabolismo , Força Compressiva , Matriz Extracelular/metabolismo , Glicosaminoglicanos/fisiologia , Humanos , Técnicas In Vitro , Microscopia Eletrônica de Transmissão , Dente Molar , Resistência à Tração , Desmineralização do Dente
16.
Microsc Res Tech ; 80(6): 627-633, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28177560

RESUMO

PURPOSE: To evaluate the influence of irrigation protocols and drying procedures on the bond strength of two methacrylate-based sealers to dentin and the associated failure pattern using scanning electron microscopy (SEM). MATERIALS AND METHODS: Fifty single-rooted human teeth were prepared with an irrigation protocol using either 5.25% sodium hypochlorite (NaOCl) or 2% chlorhexidine (CHX) and 17% EDTA (ethylenediaminetetraacetic acid) for smear layer removal. The following subgroups were also created based on drying of the root canal walls: paper points, the canals were blot dried with paper points with the last one appearing dry; or, ethanol, excess distilled water was removed with paper points followed by dehydration with 95% ethanol for 1 min and blotting with paper points. Each group was divided into two subgroups on the basis of the root canal sealer: EndoREZ and RealSeal SE. Bond strength was measured by the push-out test. The data were analyzed by ANOVA/Tukey HSD (α = 0.05). Failure patterns were classified as adhesive, cohesive, and mixed in the SEM analysis. The failure mode was evaluated by the chi-squared test (α = 0.05). RESULTS: The roots irrigated with NaOCl showed significantly lower bond strength than the roots irrigated with CHX (p < .05). RealSeal SE showed higher bond strength when compared with EndoREZ (p < .05). The highest values of bond strength were in the CHX and ethanol groups with RealSeal SE (p < .05). An increase in adhesive failure was observed in the NaOCl and EDTA group. CONCLUSIONS: The bond strength of both methacrylate-based sealers is influenced by the irrigant protocol.


Assuntos
Clorexidina/química , Resinas Compostas/química , Metacrilatos/química , Selantes de Fossas e Fissuras/química , Irrigantes do Canal Radicular/química , Tratamento do Canal Radicular/métodos , Hipoclorito de Sódio/química , Cavidade Pulpar , Dentina/química , Humanos , Microscopia Eletrônica de Varredura , Materiais Restauradores do Canal Radicular/química , Dente/fisiologia , Raiz Dentária/fisiologia
17.
Clin Oral Investig ; 21(3): 873-878, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27129588

RESUMO

OBJECTIVES: The purpose of this study was to investigate, in vitro, the retaining of 2 % CHX gel, 2 % CHX liquid and QMix (an endodontic irrigant) within a root canal for 24 h, 30, 90, and 120 days by chemical analysis. METHODS: Eighty extracted human teeth were used for this study. The samples were divided into four groups (G1-G4), according to the chemical auxiliary substance used to perform the instrumentation: G1 (control): distilled water, G2: 2 % CHX gel, G3: 2 % CHX liquid, and G4: QMix. The roots were prepared up to the instrument #45 by serial instrumentation. Longitudinal grooves were carved on the free surfaces of the roots, providing 2 halves of each root and resulting in 40 samples per group. Each group was randomly divided into four subgroups (n = 10), and substantivity was evaluated after 24 h, 30, 90, and 120 days. The amount of 2 % CHX gel, 2 % CHX liquid, and QMix (in micrograms) was measured through reverse-phase high-performance liquid chromatography. Statistical analysis was performed by ANOVA and Games-Howell test for post-hoc comparisons (α = 0.05). RESULTS: CHX gel, CHX liquid, and QMix were retained in dentin up to 120 days. Significantly less substantivity was observed for QMix, irrespective of the period of time. Statistically significant higher values were observed for CHX gel after 24 h, while no differences were noted between CHX gel and CHX liquid after 30, 90, and 120 days of evaluation (p < 0.05). CONCLUSIONS: Two percent CHX (gel and liquid) and QMix are retained in root canal dentin for up to 120 days. CLINICAL RELEVANCE: This study proposes an alternative of auxiliary chemical substance to be used during the chemo-mechanical preparation.


Assuntos
Anti-Infecciosos Locais/farmacologia , Biguanidas/química , Clorexidina/química , Dentina/efeitos dos fármacos , Polímeros/química , Irrigantes do Canal Radicular/química , Humanos , Técnicas In Vitro
18.
J Conserv Dent ; 20(5): 302-306, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29386775

RESUMO

Aim: To evaluate the effects of sodium hypochlorite (NaOCl), chlorhexidine (CHX), and two naturally derived reducing agents on the bond strength of epoxy resin-based sealer to root dentin. Materials and Methods: A total of 60 single-rooted human teeth were prepared using ProTaper (Dentsply Tulsa Dental Specialties, Johnson City, TN, USA) and an irrigation protocol including 5% NaOCl or 2% CHX gel, and ethylenediaminetetraacetic acid (EDTA), for smear layer removal. The following subgroups (n = 10) were also assessed according to the naturally derived reducing agent used: no agent (control group); grape seed extract (GSE); and green tea. Root canals were filled with gutta-percha and AH Plus (Dentsply DeTrey, Konstanz, Germany). Bond strength was measured using the push-out test, and statistical analyses were performed using ANOVA; failure patterns (modes) were classified as adhesive, cohesive, or mixed. The types of failure modes were evaluated using the Chi-squared test at α =0.05. Results: The irrigation protocols demonstrated similar bond strength values (P > 0.05). However, the Chi-squared test revealed significant differences in failure mode among the groups (P < 0.05). An increase in the incidence of adhesive failures was observed for the NaOCl and EDTA groups. The other groups demonstrated a prevalence of mixed and cohesive failures. Conclusion: The irrigation protocols and use of naturally derived reducing agents had no effect on the bond strength of the resin-based sealer to dentin; however, improvement was evident in the adhesion quality of AH Plus to NaOCl-treated root dentin, due to the prevalence of cohesive failure.

19.
Int J Prosthodont ; 29(4): 351-3, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27479340

RESUMO

PURPOSE: This study evaluated the vertical misfit of implant-supported frameworks made using different techniques to obtain passive fit. MATERIALS AND METHODS: Thirty three-unit fixed partial dentures were fabricated in cobalt-chromium alloy (n = 10) using three fabrication methods: one-piece casting, framework cemented on prepared abutments, and laser welding. The vertical misfit between the frameworks and the abutments was evaluated with an optical microscope using the single-screw test. Data were analyzed using one-way analysis of variance and Tukey test (α = .05). RESULTS: The one-piece casted frameworks presented significantly higher vertical misfit values than those found for framework cemented on prepared abutments and laser welding techniques (P < .001 and P < .003, respectively). CONCLUSION: Laser welding and framework cemented on prepared abutments are effective techniques to improve the adaptation of three-unit implant-supported prostheses. These techniques presented similar fit.


Assuntos
Prótese Parcial Fixa , Materiais Dentários , Planejamento de Prótese Dentária , Teste de Materiais/métodos
20.
Braz Dent J ; 27(2): 228-33, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27058389

RESUMO

The aim of this study was to evaluate the bond strength of a composite resin to glass-fiber post (GFP) treated or not with phosphoric acid, silane coupling agent, and unfilled resin. GFPs were etched or not with 37% phosphoric acid and different surface coating applied: silane coupling agent, unfilled resin, or both. Composite resin blocks were built around a 4-mm height on the GFP. Unfilled resin (20 s) and composite resin (40 s) were light activated by a light-emitting diode unit. The specimens were stored in distilled water at 37 °C for 24 h. Microtensile bond test was performed using a mechanical testing machine until failure (n=10). The data were analyzed using two-way ANOVA followed by Student-Newman-Keuls' test (p<0.05). Failure modes were classified as adhesive, mixed, or cohesive failures. Additional specimens (n=3) were made to analyze the bonded interfaces by scanning electron microscopy. The statistical analysis showed the factor 'surface coating' was significant (p<0.05), whereas the factor 'HP etching' (p=0.131) and interaction between the factors (p=0.171) were not significant. The highest bond strength was found for the silane and unfilled resin group (p<0.05). A predominance of adhesive and cohesive failures was found. Differences regarding the homogeneity and thickness of the unfilled resin layer formed by different GFP surface treatments were observed. The application of silane and unfilled resin can improve the bond strength between GFP and resin composite.


Assuntos
Condicionamento Ácido do Dente , Técnica para Retentor Intrarradicular , Humanos , Microscopia Eletrônica de Varredura , Propriedades de Superfície
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