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Rev. bras. ortop ; 58(1): 173-178, Jan.-Feb. 2023. graf
Article in English | LILACS | ID: biblio-1441355


Abstract The failure of ligament reconstruction has different risk factors, among which we can highlight the period before its incorporation, which is a mechanically vulnerable period. Loss of resistance over time is a characteristic of living tissues. Dissection with bone insertions of the cruciate ligaments of animal models is not described; however, it is essential for monoaxial assays to extract information from tests such as relaxation. The present work describes the dissection used for the generation of a test body for the performance of nondestructive tests to evaluate the mechanical behavior. We performed dissection of four porcino knee ligaments, proposing a dissection technique for the cruciate ligaments with bone inserts for comparison with collateral ligaments. The ligaments were submitted to relaxation tests and had strain gauges placed during the tests. The results showed viscoelastic behavior, validated by strain gauges and with a loss over time; with some ligaments presenting with losses of up to 20%, a factor to be considered in future studies. The present work dissected the four main ligaments of the knee demonstrating the posterior approach that allows maintaining their bone insertions and described the fixation for the monotonic uniaxial trials, besides being able to extract the viscoelastic behavior of the four ligaments of the knee, within the physiological limits of the knee.

Resumo A falha da reconstrução ligamentar tem diferentes fatores de risco, dentre os quais podemos destacar o período antes da sua incorporação, o qual configura um período mecânico vulnerável. A perda de resistência ao longo do tempo é uma característica dos tecidos vivos. A dissecção com as inserções ósseas dos ligamentos cruzados de modelos animais não é descrita; todavia, para os ensaios monoaxiais, é fundamental extrair as informações de ensaios como os de relaxação. O presente trabalho realiza a descrição da dissecção utilizada para a geração de corpo de prova para a realização de ensaios não destrutivos para avaliar o comportamento mecânico. Realizamos dissecção de quatro ligamentos de joelho porcino, propondo uma técnica de dissecção para os ligamentos cruzados com as inserções ósseas para comparação com os colaterais. Os ligamentos foram submetidos a testes de relaxação e foram colocadas strain gauges durante os testes. Os resultados mostraram comportamento viscoelástico, validado pelas strain gauges e com uma perda ao longo do tempo, sendo que, em alguns ligamentos, as perdas chegaram a até 20%, fator este a ser considerado em trabalhos futuros. O presente trabalho dissecou os quatro principais ligamentos do joelho, demonstrando a abordagem posterior que permite manter as suas inserções ósseas e descrevendo a fixação para os ensaios uniaxiais monotônicos, além de ter conseguido extrair o comportamento viscoelástico dos quatro ligamentos do joelho dentro dos limites fisiológicos do joelho.

Animals , Tensile Strength , Biomechanical Phenomena , Dissection , Knee Joint
Rev. estomatol. Hered ; 33(1): 18-25, ene. 2023. tab
Article in English | LILACS, LIPECS | ID: biblio-1441862


Objective: To evaluate the microtensile bond strength in different dentine conditions (etched-E, non-etched-N, dry-D and wet-W) of a multimode adhesive (Scotchbond Universal-SU, 3M/ESPE) and a total etching adhesive (Ambar-AB, FGM) using a sonic device (Smart Sonic Device-SD, FGM). Material and methods: In this in vitro study, ninety six sound extracted human molars were divided into 12 groups (n=8) according to different dentine conditions and adhesive systems. Enamel was removed and the middle dentine surfaces were polished. Each adhesive system was applied according to the different dentine conditions, and composite resin blocks were incrementally built up and stored for 24 hours. Specimens were sectioned into sticks and bond strength data were analyzed with the Kruskal-Wallis test and Mann-Whitney U tests. Results: No effects of sonic application and were observed. In general, AB showed lower results compared to the SU. E and N conditions did not statistically affect the bond strength of SU groups. Dry dentine presented statistically superior bond strength values when compared to wet dentine for SU/E/SD group. Conclusion: Adhesion of dry dentine with multimode adhesive system may be superior to wet dentine with sonic application. The modes of application had no influence in bond strength of studied adhesives.

Objetivo: Evaluar la resistencia de la unión microtensil en diferentes condiciones de dentina (grabado-E, sin grabado-N, seco-D y húmedo-W) de un adhesivo multimodo (Scotchbond Universal-SU, 3M/ESPE) y un adhesivo de grabado total (Ambar-AB, FGM) utilizando un dispositivo sónico (Smart Sonic Device-SD, FGM). Material y Métodos: En este estudio in vitro, noventa y seis molares humanos extraídos sanos se dividieron en 12 grupos (n=8) de acuerdo con diferentes condiciones de dentina y sistemas adhesivos. Se eliminó el esmalte y se pulieron las superficies centrales de la dentina. Cada sistema adhesivo se aplicó de acuerdo con las diferentes condiciones de dentina, y los bloques de resina compuesta se acumularon de forma incremental y se almacenaron durante 24h. Las muestras se seccionaron en barras y los datos de resistencia de la unión se analizaron con la prueba de Kruskal-Wallis y la prueba de U de Mann-Whitney. Resultado: No se observaron efectos de la aplicación sónica. En general, AB mostró resultados más bajos en comparación con el SU. Las condiciones E y N no afectaron estadísticamente la fuerza de unión de los grupos SU. La dentina seca presentó valores de fuerza de adhesión estadísticamente superiores en comparación con la dentina húmeda para el grupo SU/E/SD. Conclusión: La adhesión de la dentina seca con un sistema adhesivo multimodo puede ser superior a la dentina húmeda con aplicación sónica. Los modos de aplicación no tuvieron influencia en la resistencia de la unión de los adhesivos estudiados.

Humans , Tensile Strength , Dentin-Bonding Agents , Dentin , Ultrasonics , In Vitro Techniques
Braz. j. oral sci ; 22: e239389, Jan.-Dec. 2023. ilus
Article in English | LILACS, BBO | ID: biblio-1509457


Aim: The purpose of this study was to investigate the biofilm effect on the hybrid ceramic-resin cement bond strength (BS) by comparing two methods. Methods: Teeth were distributed into groups (n=5), according to the resin cement (Maxcem Elite-(MC) or NX3 Nexus-(NX)) and degradation method (24h or 7 days in distilled water; 7 or 30 days incubated with biofilm and 30 days in sterile media). Treated surfaces of Vita Enamic blocks (5x6x7mm) were luted to treated or no treated dentin surfaces and light-cured. After 24h, beams were obtained (1x1x10mm) and stored accordingly. The flexural bond strength (FBS) was assessed by four-point bending test. Additional beams were obtained from new teeth (n=5), stored for 24h or 7 days in distilled water, and submitted to a microtensile bond strength (µTBS) assay. Failure modes were determined by scanning electron microscopy (100X). The flexure strength of the cements (n=10) was assessed by a four-point bending test. Data were analyzed by 1 and 2-ways ANOVA, and Tukey's test (α=0.05). Results: There was no significant difference between the degradation methods for the FBS groups. For the µTBS, the significant difference was as follows: NX 7days > NX 24h > MC 7days = MC 24h. Failure mode was mainly adhesive and mixed, but with an increase of cohesive within cement and pre-failures for the MC groups assessed by µTBS. NX had better performance than MC, regardless of the method. Conclusions: The biofilm had no effect on the materials BS and FBS test was a useful method to evaluate BS of materials with poor performance

Tensile Strength , Microscopy, Electron, Scanning , Dental Bonding , Biofilms , Resin Cements
Pesqui. bras. odontopediatria clín. integr ; 23: e210155, 2023. tab, graf
Article in English | LILACS, BBO | ID: biblio-1507020


ABSTRACT Objective: To evaluate the mechanical properties of mini-implants (MIs) manufactured from stainless steel and compare them with conventional titanium-aluminum-vanadium alloy MIs. Material and Methods: The following groups were formed: G1 (n=24), 8×1.5 mm steel MIs; G2 (n=24), 12×2.0 mm steel MIs; and G3 (n=24), 10×1.5 mm titanium MIs. The 72 MIs were inserted in the infra zygomatic crest region of the maxilla and retromolar trigone in the jaw of 10 pigs. Pull-out, insertion torque, fracture and percussion tests were performed in order to measure the tensile strength, primary stability and fracture strength of MIs. A digital torque gauge was used to measure insertion and fracture torque, a universal mechanical testing machine was used for pull-out testing and a periotest device was used to measure the micromovement of MIs. For morphological and MI component evaluation, scanning electron microscopy (SEM) was performed. D'Agostino & Pearson, Kruskal-Wallis, and Dunn post-hoc and normality tests were used. Results: G2 insertion and fracture torques were significantly higher than G1 and G3 insertion and fracture torques (p<0.05). The pull-out and percussion tests presented similar values among the groups. SEM revealed that the fracture point was predominantly on the fourth thread for steel MIs (G1 and G2) and on the seventh thread for titanium-aluminum-vanadium MIs (G3). Conclusion: The mechanical properties of stainless steel MIs are superior to those of titanium-aluminum-vanadium alloy MIs.

Animals , Stainless Steel/chemistry , Tensile Strength , Titanium , Orthodontic Anchorage Procedures/instrumentation , Swine , Microscopy, Electron, Scanning/instrumentation , Statistics, Nonparametric , Flexural Strength , Mechanical Tests
Braz. j. oral sci ; 21: e225454, jan.-dez. 2022. ilus
Article in English | LILACS, BBO | ID: biblio-1366512


Aim: Evaluating the resin-dentin bond strength of Class II conventional and bulk-fill composite restorations, using different cavity sizes before and after aging. Methods: Seventy-five human molars were distributed into groups according to the buccolingual width of the cavities, conservative (n=25) and extended (n=50). They were divided according to the restorative material: conventional (Z100/control group) or bulk-fill resin composites (Filtek Bulk Fill/FBF; Tetric N Ceram Bulk Fill/TNCBF; Filtek Bulk Fill Flow/FBFF; Surefill SDR flow/SDR). The restored teeth were sectioned on sticks (n=50 per restorative materials + width cavities group), half were stored in Water/Ethanol 75% for 30 days and the other half were submitted to the immediate microtensile bond strength (µTBS) test. Data were analyzed applying the Three-Way Analysis of Variance (ANOVA), Bonferroni test, test t, and Weibull analyses (p<0.05). Results: SDR and FBF presented lower µTBSvalues for extended preparation when compared to the conservative preparation, before aging. After aging, only for the FBFF, a decrease in the µTBSvalues was observed. Comparing the µTBSvalues, before and after aging, the SDR demonstrated lower µTBSvalues after aging when the conservative cavity was used. A decrease in the µTBSvalues was observed for the Z100, the FBF and, the FBFF, after aging, when the extended cavity was used. Conclusion: The effect of cavity preparation and aging on the resin-dentin of Class II is material dependent. Most of the bulk-fill resin composites evaluated presented a similar performance to the conventional resin composites for all the conditions of this study

Humans , Tensile Strength , Aging , Composite Resins/analysis , Dental Cavity Preparation
Braz. j. oral sci ; 21: e226036, jan.-dez. 2022. ilus
Article in English | LILACS, BBO | ID: biblio-1393321


Dental implants could give back function, esthetics and quality of life to patients. The correct choice of the implant, especially in borderline cases, is essential for a satisfactory result. Aim: Thus, the objective of this study was to evaluate the mechanical behavior of Morse taper implants with two different prosthetic interfaces. Methods: Twenty self-locking Morse taper implants, 2.9 mm in diameter (FAC), and 20 Morse taper implants, 3.5 mm in diameter (CM) were divided into two groups (n=10), and submitted to strength to failure test, optical microscopic evaluation of fracture, metallographic analysis of the alloy, finite element analysis (FEA) and strain gauge test. A Student's t test (α = 0.05) was made for a statistical analysis. Results: For the strength to failure test, a statistically difference was observed (p <0.001) between FAC (225.0 ± 19.8 N) and CM (397.3 ± 12.5 N). The optical microscopic evaluation demonstrated a fracture pattern that corroborated with FEA ́s results. The metallographic analysis determined that the implants of the FAC group have titanium-aluminum-vanadium alloy in their composition. In the strain gauge test, there was no statistical difference (p = 0.833) between CM (1064.8 ± 575.04 µS) and FAC (1002.2 ± 657.6 µS) groups. Conclusion: Based on the results obtained in this study, ultra-narrow implants (FAC) should ideally be restricted to areas with low masticatory effort

Tensile Strength , Dental Implantation , Flexural Strength
Rev.chil.ortop.traumatol. ; 63(2): 83-86, ago.2022. ilus, graf
Article in Spanish | LILACS | ID: biblio-1436080


OBJETIVO Determinar la resistencia máxima a la tracción (RMT) de la continuación prepatelar del cuádriceps (CPC).MATERIALES Y MÉTODOS Se realizó un estudio en cadáveres humanos. Fueron incluidos diez especímenes, en los cuales se utilizaron los tercios proximal y medial de la cortical anterior de la patela para evaluar las propiedades mecánicas de la CPC. En cada espécimen, se estudió un área de sección transversal de 0,2 cm2 (A1) y 1 cm2 (A2). Se aplicó una carga gradual para determinar la RMT.RESULTADOS La mediana de la RMT en el A1 fue de 232,56 N (rango: 141,23 N a 295,33 N) y en el A2 fue de 335,30 N (rango: 216,45 N a 371,40 N). El incremento en la TMR fue significativo entre las 2 áreas (p = 0,006).CONCLUSIÓN El ignificado clínico de este estudio es que la CPC es un tejido fuerte que puede servir de anclaje seguro para reconstrucciones alrededor de la patela. Un área relativamente pequeña tolera al menos 140 N y, a medida que crece el área, también aumenta la RMT.

OBJETIVE To determine the ultimate tensile strength (UTS) of the prepatellar quadriceps continuation (PQC). MATERIALS AND METHODS A human cadaveric study was performed. Ten fresh-frozen specimens were used. The proximal and medial thirds of the anterior cortex of the patella were used to assess the mechanical properties of the PQC. In each specimen, transverse section areas measuring 0.2 cm2 (A1) and 1 cm2 (A2) were studied. A gradual load was applied to determine the UTS. RESULTS The median UTS of A1 was of 232.56 N (range: 141.23 N to 295.33 N), and that of A2 was of 335.30 N (range: 216.45 N to 371.40 N). The increment in UTS was significant between the 2 areas (p » 0.006). CONCLUSION The clinical significance of the present study lies in the fact that it shows that the PQC is a strong tissue that can be a safe anchor for reconstruction around the patella. A relatively small area supports at least 140 N, and, as the area grows, the UTS increases as well.

Humans , Male , Female , Adult , Middle Aged , Aged , Tensile Strength , Quadriceps Muscle/physiopathology , Biomechanical Phenomena , Knee Joint/physiopathology
Rev. ADM ; 79(1): 20-27, ene.-feb. 2022. ilus, tab
Article in Spanish | LILACS | ID: biblio-1361506


Los sistemas cementantes han mejorado notablemente, los objetivos que persiguen los nuevos cementos es que la adhesión sea duradera y conseguir siempre que sea posible una interface cerrada con un sellado perfecto. Se han podido desarrollar nuevas técnicas y nuevos materiales de cementación que han ido perfeccionando la unión del material restaurador al diente. En el presente estudio se compara la fuerza de adhesión a dentina de cementos de autograbado y cementos de grabado total para comprobar los efectos positivos en el grabado de la dentina. Para el estudio se utilizaron dos cementos a base de resina (RelyX U200 Clicker 3M y RelyX Ultimate 3M). Se encapsularon 40 molares en acrílico en dos grupos de 20 muestras para la aplicación de dos sistemas cementantes de autograbado (grupo 1) y de grabado total (grupo 2), respectivamente, se desgastaron hasta descubrir la dentina; siguiendo las especificaciones del fabricante se colocó el cemento en cada grupo, y después se sometieron a pruebas de cizalla en una máquina de ensayo universal Instron. La medida expresada en megapascales (MPa) fue: grupo 1 = 7.5569 y grupo 2 = 12.6444. En este caso fueron analizados dos grupos, tomándose la primera significancia bilateral. Se realiza la prueba en t de Student, con 95% de intervalo de confianza en la diferencia, demostrando así que el cemento RelyX Ultimate 3M tiene mayor fuerza de adhesión que el cemento RelyX U200 Clicker 3M. Nuestra investigación fue factible y llegamos a nuestro propósito, en el cual comprobamos la mayor adhesión de cementos de grabado total, los cuales son sometidos a un previo tratamiento del diente (AU)

Humans , Adolescent , Adult , Acid Etching, Dental , Cementation , Dentin-Bonding Agents , Resin Cements , Shear Strength , Tensile Strength , Dentin/drug effects
Journal of Peking University(Health Sciences) ; (6): 83-88, 2022.
Article in Chinese | WPRIM | ID: wpr-936116


OBJECTIVE@#To investigate the effect of a noval radio-frequency atmospheric-pressure glow discharge (RF-APGD) plasma jet on crosslinking of dentin collagen.@*METHODS@#(1) Twenty intact third molars were collected. The middle dentin discs were prepared for each tooth by low-speed water-cooled Isomet saw, and then immersed in 10% (mass fraction) H3PO4 solution for 16 h to obtain fully demine-ralized dentin collagen. The twenty dentin discs were then randomly divided into five groups. The control group was untreated while the four experimental groups were treated by plasma jet with gas temperature of 4 ℃ for different times (20 s, 30 s, 40 s, and 50 s). The structure and crosslinking degree of dentin collagen were characterized by attenuated total reflection-Fourier transform infrared spectroscopy. The surface morphology of demineralized dentin was observed by scanning electron microscope, and the microstructure was observed by transmission electron microscope. (2) Fourty non-caries third molars were collected to prepare 5 g fine dentin powder, then completely demineralized with 10% H3PO4 solution. The control group was untreated, while the four experimental groups were treated by plasma jet for 20 s, 30 s, 40 s and 50 s. The crosslinking degree of each group was determined by ninhydrin colorimetric method. (3) Forty intact third molars were collected to obtain dentin strips. Only two central symmetrical dentin strips (nasty 80) were taken from each tooth and immersed in 10% H3PO4 solution for 16 h to obtain fully demineralized dentin collagen. Eighty dentine collagen fiber strips were randomly divided into five groups. The control group was untreated and the axial surfaces of dentin collagen fiber strips in the expe-rimental groups were treated with the plasma jet for 20 s, 30 s, 40 s and 50 s. The ultimate tensile strength of dentin was measured by universal mechanical machine.@*RESULTS@#(1) The surface morphology of demineralized dentin observed by scanning electron microscope showed that the network structure of collagen fibers on the surface of demineralized dentin treated with the plasma jet for 20 s, 30 s and 40 s could maintain the uncollapsed three-dimensional structure, and part of the microstructure was destroyed after plasma jet treated for 50 s. After being treated by plasma jet for 20 s, 30 s and 40 s, the three-dimensional structure was uncollapsed, and the typical periodic transverse pattern of natural type Ⅰ collagen fiber could be seen. The results of infrared spectra showed that the secondary conformation of dentin collagen fibers was the same as that of the control group after being treated with the plasma jet, and the intensity of amide band was significantly increased after being treated for 30 s and 40 s. (2) The results of ninhydrin crosslinking test showed that the crosslinking ratio of dentin collagen treated by plasma jet for 30 s and 40 s was the highest, and the difference was statistically significant (P < 0.05). (3) The results of dentin ultimate tensile strength showed that the control group was (1.67±0.24) MPa, and the plasma jet treated 20 s, 30 s, 40 s and 50 s groups were (4.21±0.15) MPa, (7.06±0.30) MPa, (7.32±0.27) MPa, and (6.87±0.17) MPa, which were significantly different from that of the control group (P < 0.05).@*CONCLUSION@#The novel RF-APGD plasma jet treatment can promote the crosslinking degree of demineralized dentin collagen and improve their ultimate tensile strength.

Collagen , Dental Bonding , Dentin , Dentin-Bonding Agents , Microscopy, Electron, Scanning , Tensile Strength
Chinese Journal of Stomatology ; (12): 173-181, 2022.
Article in Chinese | WPRIM | ID: wpr-935845


Objective: To study the effect of hydroxyapatite (HA) based agents on the bonding properties of universal adhesive with different application modes, and to provide evidence for the use of adhesives after desensitization treatment. Methods: Sixty impacted third molars were extracted and selected (acquired from Department of Oral and Maxillofacial Surgery, College of Stomatology, Xi'an Jiaotong University). Four third molars were used to prepare 1 mm thick dentin disks and treated with 1% citric acid to simulate sensitive tooth models. The dentin surfaces were observed by scanning electron microscope (SEM) after treating with no desensitization (control group), desensitized by HA based toothpaste Biorepair and Dontodent Sensitive respectively (desensitizing toothpaste A group and B group), or HA paste treatment (desensitizing paste group ) (n=2 per group). The remaining teeth were selected to expose the mid-coronal dentin and establish dentin sensitivity models. Then, the specimens were divided into 4 former groups and received corresponding treatment. Each group was randomly divided into 2 subgroups, and intermediately strong universal adhesive (G-Premio Bond) was applied on the desensitized dentin by either etch-and-rinse mode or self-etch mode. Resin-dentin slice specimens (n=4 per subgroup), microtensile specimens (n=20 per subgroup) and slice specimens (n=6 per subgroup) were prepared. The microstructure and nanoleakage of the adhesive interfaces were observed by scanning electron microscopy (SEM). The microtensile strength (bond strength) and fracture mode were tested and recorded. The water permeability of the adhesive interface was observed by laser scanning confocal microscopy (LSCM). Results: SEM showed that desensitizing toothpaste and desensitizing paste could partially or entirely occlude most of the dentin tubules. For the etch-and-rinse mode, the bond strength of specimens treated with toothpaste A [(40.98±4.60) MPa], toothpaste B [(40.89±4.64) MPa] and HA paste [(41.48±3.65) MPa] was significantly higher than that of the control group [(38.58±4.28) MPa] (F=3.89,P<0.05). There was no statistically significant difference in bond strength among the 4 subgroups for self-etch modes (F=0.48,P>0.05). After desensitization, the bond strength of the control group and desensitizing groups in the self-etch mode was significantly higher than that in the etch-and-rinse mode (P<0.05). The overall fracture modes were mixed failure and interfacial failure in the control group and desensitizing groups. SEM showed speckled silver-stained particles deposited along the bottom of the hybrid layer on the bond interface of etch-and-rinse mode, and there were few silver-stained particles deposited on the bond interface of self-etch mode. LSCM showed continuous linear penetration in the hybrid layer of etch-and-rinse mode subgroups and discontinuous linear penetration in the hybrid layer of self-etch mode subgroups. Conclusions: HA based desensitizers have no adverse effect on the bond strength of intermediately strong universal adhesive and show good bonding performance accompanied with the self-etch mode.

Humans , Adhesives , Dental Bonding , Dental Cements , Dentin , Dentin-Bonding Agents , Durapatite , Materials Testing , Microscopy, Electron, Scanning , Resin Cements , Tensile Strength
Journal of Central South University(Medical Sciences) ; (12): 226-237, 2022.
Article in English | WPRIM | ID: wpr-929026


OBJECTIVES@#Root canal therapy is the most effective and common method for pulpitis and periapical periodontitis. During the root canal preparation, chemical irrigation plays a key role. However, sodium hypochlorite (NaOCl), the widely used irrigation fluid, may impact the bonding strength between dentin and restorative material meanwhile sterilization and dissolving. Therefore, it's important to explore the influence of NaOCl on the adhesion between dentin and restoration materials to ensure clinical efficacy. This study aims to explore the effect of NaOCl on dentine adhesion and evaluate the effect of dentine adhesion induced by sodium erythorbate (ERY), and to provide clinical guidance on dentin bonding after root canal therapy.@*METHODS@#Seventy freshly complete extracted human third molars aged 18-33 years old, without caries and restorations were selected. A diamond saw was used under running water to achieve dentine fragments which were divided into 10 groups with 14 fragments in each group: 2 control [deionized water (DW)±10% ERY] and 8 experimental groups (0.5%, 1%, 2.5%, and 5.25% NaOCl±10% ERY). The dentine specimens in the control group (treated with DW) and the experimental groups (treated with 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl) were immersed for 20 min using corresponding solutions which were renewed every 5 min. The other 5 groups were immersed in 10% ERY for 5 min after an initial washing with DW for 1 min. Then, we selected 4 dentine fragments from all 14 fragments in each group and the numbers and diameters of opening dentinal tubules were observed under scanning electron microscope (SEM). The other 10 dentine fragments from each group were used to make adhesive samples by using self-etch adhesive wand composite resin. All the above adhesive samples were sectioned perpendicular to the bonded interface into 20 slabs with a cross-sectional area of 1 mm×1 mm using a diamond saw under the cooling water, and then the morphology of 10 slabs in each group's bonding interface was observed from aspects of formation of resin tags, depth of tags in dentin, and formation of hybrid layer under SEM. The other 10 slabs of each group's microtensile bond strength and failure modes were also analyzed.@*RESULTS@#Among the 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl groups, the number and diameter of patent dentinal tubules gradually increased with the rise of concentration of NaOCl solution (all P<0.05). Among the DW, 0.5% NaOCl, 1% NaOCl, 2.5% NaOCl, and 5.25% NaOCl groups, the number and diameter of patent dentinal tubules increased after using ERY, but without significant difference (all P>0.05). Among the DW, 0.5% NaOCl, 1% NaOCl, and 2.5% NaOCl groups, the scores of formation of resin tags under SEM gradually increased with the increase of concentration of NaOCl solution, while the score in the 5.25% NaOCl group decreased significantly compared with the score of the 2.5% NaOCl group (P<0.05). There was no significant difference between using 10% ERY groups and without using 10% ERY groups (all P>0.05). The scores of length of the tags under SEM in the 5.25% NaOCl group was significantly higher than the scores of DW, 0.5% NaOCl, and 1% NaOCl groups (all P<0.05), and it was also higher than the score of the 2.5% NaOCl group, but without significant difference (P>0.05). There was no significant difference between using 10% ERY groups and without using 10% ERY groups (P>0.05). The scores of formation of hybrid layer under SEM in the 2.5% NaOCl and 5.25% NaOCl groups significantly decreased compared with the score of the DW group (all P<0.05). There were significant differences between the 2.5% NaOCl±10% ERY groups and between the 5.25% NaOCl±10% ERY groups (all P<0.05). Microtensile bond strength was greater in the 0.5% NaOCl, 1% NaOCl, and 2.5% NaOCl groups, but lower in the 5.25% NaOCl group than that in the DW group (all P<0.05). There were significant differences between the 2.5% NaOCl±10% ERY groups and between the 5.25% NaOCl±10% ERY groups (all P<0.05). The incidence of type "Adhesive" of failure modes in the 5.25% NaOCl group was significantly higher than that in other groups (all P<0.05), while the incidence of type "Adhesive" in the 5.25% NaOCl+10% ERY group was lower than that in the 5.25% NaOCl group (P<0.05).@*CONCLUSIONS@#The bonding strength to dentine increases with the increase of NaOCl concentration when the concentration lower than 2.5%; whereas it is decreased at a higher concentration (such as 5.25%). 10% ERY has a definite recovery effect on attenuated bonding strength to 5.25% NaOCl-treated dentine.

Adolescent , Adult , Humans , Young Adult , Ascorbic Acid , Dental Bonding , Dentin , Dentin-Bonding Agents/pharmacology , Diamond/pharmacology , Materials Testing , Microscopy, Electron, Scanning , Resin Cements/pharmacology , Sodium Hypochlorite/pharmacology , Tensile Strength , Water/pharmacology
Arq. odontol ; 58: 131-139, 2022. tab, graf
Article in English | LILACS, BBO | ID: biblio-1411880


Aim: To compare the influence of prophylaxis with sodium bicarbonate and amino acid glycine powder on the bond strength of bovine teeth enamel and on the properties of two adhesive systems. Methods:Thirty-six extracted bovine incisors were randomly divided into six groups (n = 6) according to the prophylactic treatment received: no prophylactic treatment (NT), sodium bicarbonate powder (SB), and glycine powder (GL). Each group was subdivided into 2 groups based on what adhesive systems were used: conventional system (A) and universal system (B). Composite resin was applied on the buccal surface of the teeth in a block measurement 8x8x6 mm. The specimens were cut to obtain beams measuring 1.0 x 1.0 mm and were subjected to microtensile bond strength tests. Results were compared using two-way ANOVA (p ≤ 0.05). Results: The GLA group obtained the highest bond strength value for the conventional adhesive (18.97 MPa), but the GLB group obtained a lower strength value than the SBB group (GLB: 21.05 MPa and SBB: 22.29 MPa) (p < 0.05). Conclusions: Cleaning of the enamel surface increases the adhesive properties of restorative materials, and the bond strength was more effective in the group that received glycine prophylaxis and the conventional adhesive system.

Objetivo:Comparar a influência da profilaxia com bicarbonato de sódio e ClinproProphy ™ na resistência de união do esmalte de dentes bovinos e nas propriedades de dois sistemas adesivos.Métodos: Trinta e seis incisivos bovinos extraídos foram divididos aleatoriamente em 6 grupos (n = 6), cada um de acordo com o tratamento profilático recebido: nenhum tratamento profilático (NT), bicarbonato de sódio em pó (SB), glicina em pó (GL). Cada grupo foi subdividido em 2 grupos com base nos sistemas adesivos utilizados: sistema convencional (A) e sistema universal (B). A resina composta foi aplicada na superfície bucal dos dentes em um bloco de 8x8x6 mm. As amostras foram cortadas para obter blocos medindo 1,0 x 1,0 mm e submetidas a testes de resistência de união por microtração. Os resultados foram comparados usando o teste two-way ANOVA (p ≤ 0,05). Resultados: O grupo GLA obteve o maior valor de resistência de união para o adesivo convencional (18,97 MPa), mas o grupo GLB obteve um valor de resistência menor que o grupo SBB (GLB: 21,05 MPa e SBB: 22,29 MPa) (p < 0,05). Conclusão: A limpeza da superfície do esmalte aumenta as propriedades adesivas dos materiais restauradores, e a resistência adesiva foi mais eficaz no grupo que recebeu profilaxia com glicina e sistema adesivo convencional.

Tensile Strength , Dental Bonding , Dental Enamel , Dental Prophylaxis , Glycine
Pesqui. bras. odontopediatria clín. integr ; 22: e210058, 2022. tab, graf
Article in English | LILACS, BBO | ID: biblio-1365226


ABSTRACT Objective To evaluate and compare the effect of 17% Ethylenediaminetetraacetic Acid (EDTA), 9% Etidronic acid (HEDP), and 7% Maleic acid (MA) on the push-out bond strength of NeoMTA Plus sealer to the coronal, middle, and apical thirds of root canal dentin. Material and Methods Forty single-rooted human maxillary central incisors were selected and decoronated to 12 mm long root fragments. Working length was established and root canals were then enlarged up to rotary Protaper F3. After each instrumentation, the root canal was irrigated with 2.5% NaOCl. For the final irrigation regimen, the specimens were divided into 4 groups (n=10) and treated with EDTA, HEDP, MA or Saline. Root canals were coated with NeoMTA Plus sealer, and obturation was done with single cone obturation technique. Subsequently, three horizontal sections were taken from the coronal, middle and apical thirds of each specimen, and POBS was measured using a universal testing machine. The type of bond failures was assessed under a stereomicroscope. Statistical analysis was done with One-way ANOVA with Tukey's Post hoc analysis. Results MA and EDTA showed the highest POBS. There was no significant difference in bond strength between MA and EDTA (p>0.05). HEDP and Saline showed lower POBS. Among all the four groups, the coronal third showed the highest values, followed by middle and apical thirds. Conclusion The type of chelating agent used during the root canal treatment significantly affects the bond strength of NeoMTA Plus to the root canal dentin.

Humans , Root Canal Filling Materials , Tensile Strength , Chelating Agents/chemistry , Dental Cements , Endodontics , Analysis of Variance , Edetic Acid , Etidronic Acid , Dental Materials/chemistry , Incisor , India , Maleic Hydrazide
Braz. j. oral sci ; 20: e210328, jan.-dez. 2021. ilus
Article in English | BBO, LILACS | ID: biblio-1253738


Aim: The in vitro study evaluated the effect of different concentrations of green tea extract solution (GT) on the bonding durability of etch-and-rinse adhesive system to caries dentin affected (CAD). Methods: Dentinal surfaces of human third molars were polished and submitted to a microbiological caries induction protocol for 14 days. After removal of the infected dentin layer, the samples were randomly divided into 4 groups (n= 10), according to the concentration of GT solution applied in CAD, after acid etching: 0.05%; 0.2%; 2% and NT (no treatment ­ control). After application of a etch-and-rinse adhesive system (Adper Single Bond 2, 3M ESPE), composite resin restorations were performed on the dentin. After 24 hours, the resin-dentin blocks were sectioned 1mm2 specimens, which were subjected to the microtensile test immediately or after 6 months of storage in water. Data were submitted to two-way ANOVA for randomized blocks and Tukey test (α= 5%). Results: There was no effect of double interaction (p= 0.934). The application of 0.2% GT promoted a statistically significant increase in dentin bond strength values in comparison to the condition where GT was not used (p=0.012). There was a significant decrease of bond strength after 6 months of storage, regardless of dentin pretreatment (p = 0.007). The G test identified that there was no statistical difference regarding failure mode (p= 0.326). Conclusion: The concentration of 0.2% improved the bond strength of an etch-and-rinse adhesive system to caries affected dentin, however, none of dentin pretreatments could prevent the decrease in bond strength over time

Tensile Strength , Camellia sinensis , Dental Caries , Dentin
Rev. Asoc. Odontol. Argent ; 109(3): 149-157, dic. 2021. ilus, tab
Article in Spanish | LILACS | ID: biblio-1370323


Objetivo: Describir las fallas en diferentes sistemas de implantes al ser sometidos a fuerzas de torsión creciente, de- terminar el torque en el cual aparece un daño medible en el implante o alguno de sus componentes y especificar la falla más frecuente. Materiales y métodos: Se realizó un estudio experi- mental in vitro. Se utilizaron 88 implantes agrupados según diseño y marca comercial (Federa, Rosterdent, Biomet 3i, Tree-Oss, B&W, ML) en 11 grupos de 8 implantes cada uno. Éstos fueron inmovilizados en acrílico y fijados en una pren- sa. Se aplicó una fuerza de torsión creciente con torquímetro de precisión digital hasta la aparición de alguna falla en el implante o sus componentes. Se registró el torque en el que se produjo la falla. Se realizó estadística descriptiva para el análisis de datos. Resultados: El 100% de los implantes o alguno de sus componentes mostraron una falla detectable al ser sometidos a fuerzas de torsión creciente (rango de torque: 83,5 Ncm ­im- plante con conexión cono morse 8 grados­ a 384 Ncm ­implan- te de conexión interna sin montar­). El torque promedio más bajo en el que aparecieron los daños fue 103,75 (±8,08) Ncm para implantes de conexión interna tipo cono morse, mientras que el más alto fue 279,87 (±89,73) Ncm para implantes de conexión interna sin montar. La falla más frecuente (28,4%) fue la fractura del tornillo del portaimplante y falseo del hexá- gono externo simultáneamente. Conclusión: Las fallas detectables a fuerzas de torsión creciente ocurrieron entre 83,5 Ncm y 384 Ncm. La falla rei-terada fue la fractura del tornillo del portaimplante y falseo del hexágono simultáneamente (AU)

Aim: To describe the failures in different implant sys- tems when subjected to increasing torsional forces, deter- mine the torque at which measurable damage occurs to the implant or one of its components, and determine the most frequent failure. Materials and methods: This was an experimental in vitro study. A total 88 implants were used, grouped accord- ing to design and trademark (Federa, Rosterdent, Biomet 3i, Tree-Oss, B&W, ML) into 11 groups of 8 implants each. The implants were immobilized in Duralay acrylic and fixed in a vice. Increasing torsional force was applied with a digital pre- cision torque wrench until the occurrence of any failure in the implants or their components. The torque at which the failure occurred was recorded. Descriptive statistics were performed for data analysis. Results: 100% of the implants or any of their compo- nents showed a detectable failure when subjected to increas- ing torsional forces (force range: 83.5 Ncm in an implant with 8-degree Morse taper connection to 384 Ncm in an implant with unmounted internal connection). The lowest average torque at which damage occurred was 103.75 (±8.08) Ncm for conical implants with Morse internal connection, while the highest was 279.87 (±89.73) Ncm for implant with unmounted internal connection. The most frequent failure (28.4%) was fracture of the implant retaining screw and distortion of the external hexagon simultaneously (AU)

Tensile Strength , Dental Implants , Torsion, Mechanical , In Vitro Techniques , Dental Restoration Failure , Torque
Rev. cuba. estomatol ; 58(4)dic. 2021.
Article in Spanish | LILACS, CUMED | ID: biblio-1408356


Introducción: Es frecuente el desprendimiento de los espigos de fibra de vidrio por pérdida de adhesión cuando son sometidos a las fuerzas masticatorias. Objetivo: Comparar in vitro la resistencia a las fuerzas de tracción de espigos de fibra de vidrio y anatomizado con un mismo cemento. Métodos: Estudio in vitro, de tipo experimental. Se seleccionaron 20 premolares extraídos por motivos ortodónticos que fueron distribuidos aleatoriamente en dos grupos. Se les realizó el tratamiento de conductos por un especialista, la preparación fue manual y la técnica de obturación por condensación lateral. Los dientes fueron preparados para, en forma estándar, recibir el espigo de fibra de vidrio y anatomizados con resina. Para ambos grupos la cementación siguió el protocolo sugerido por el fabricante de Allcem Core® (cemento dual). Los especímenes fueron troquelados en acrílico de autocurado. Para luego ser sometido a fuerza de tracción vertical en la máquina de pruebas de materiales (Instrom©). Resultados: En el grupo de dientes con espigos anatomizados se obtuvo una media de 31 Kg/F, postes de fibra de vidrio 12,47 Kg/F. Según las pruebas de Shapiro-Wilk, las muestras presentaron distribución normal (p > 0,05). Se contrastó la hipótesis con la prueba de t de Student y se encontró diferencia estadística altamente significativas entre los grupos (p = 0,001) Conclusiones: Existe una mayor resistencia a la tracción vertical en los espigos anatomizados(AU)

Introduction: Fiberglass posts often fall off their position due to loss of adhesive capacity when they are subjected to masticatory force. Objective: Compare in vitro the tensile bond strength of fiberglass and anatomized posts cemented with the same adhesive material. Methods: An in vitro experimental study was conducted. A selection was made of 20 premolars extracted by orthodontic indication which were then randomly distributed into two groups. The premolars underwent root canal treatment by a specialist. The preparation was manual and sealing was performed by lateral condensation. The teeth were prepared in the standard manner to receive the fiberglass and resin-anatomized posts. In both groups' cementation followed the protocol suggested by the manufacturer of Allcem Core® (dual cement). The specimens were stamped in self-curing acrylic. Next, they were subjected to vertical tensile strength in an materials testing machine (Instrom©). Results: The mean values obtained were 31 kg/F for teeth with anatomized posts and 12.47 kg/F for fiberglass posts. According to Shapiro-Wilk tests, the samples exhibited a normal distribution (p > 0.05). The hypothesis was contrasted with Student's t test, obtaining a highly significant statistical difference between the groups (p = 0.001). Conclusions: Vertical tensile bond strength is greater in anatomized posts(AU)

Humans , Bite Force , Dental Cements/adverse effects , Tensile Strength
Braz. dent. j ; 32(4): 106-115, July-Aug. 2021. tab, graf
Article in English | LILACS, BBO | ID: biblio-1345518


Abstract The aim of this study was to evaluate the effect of 2% chlorhexidine digluconate (CHX) on microtensile bond strength (µTBS) between an adhesive system and under 3 dentin conditions. For that, this study evaluated the adhesive interface at initial, after 6 months and 1 year of storage. Forty-eight human third molars were prepared and randomly divided into 3 groups, according to dentin substrates: sound dentin (Sd), caries-infected dentin (Ci) and caries-affected dentin (Ca). The groups were subdivided into two according to the dentin pre-treatment: application of 2% CHX or without pre-treatment (control). The dentin surfaces were etched with 35% phosphoric acid gel and bonded with Adper Single Bond 2 (3M ESPE) adhesive system according to manufacturer's instructions. Subsequently, the specimens were stored in deionized water at 37°C for 24h, 6 months and 1 year. Two additional teeth were used to analyze the bonding interfaces by SEM. Data was submitted to three-way ANOVA in a split plot design and Tukey's test (α = 0.05). The results showed that Ci decreased µTBS values when compared to Ca and Sd, regardless storages time or treatment. Stored samples for 6 months and 1 year decreased the µTBS for the control group, but no difference was found between storages time for the CHX group. As a conclusion, the 2% CHX application after etching showed improved dentin bond strength in the storage time, regardless of the substrates evaluated.

Resumo O objetivo deste estudo foi avaliar o efeito do digluconato de clorexidina 2% (CHX) na resistência de união à microtração (µTBS) entre um sistema adesivo e sob 3 condições de dentina. Para tanto, este estudo avaliou a interface adesiva no início, após 6 meses e 1 ano de armazenamento. Quarenta e oito terceiros molares humanos foram preparados e divididos aleatoriamente em 3 grupos, de acordo com os substratos dentinários: dentina hígida (Dh), dentina infectada por cárie (Di) e dentina afetada por cárie (Da). Os grupos foram subdivididos em dois de acordo com o pré-tratamento: aplicação de CHX 2% ou sem pré-tratamento (controle). As superfícies da dentina foram condicionadas com gel de ácido fosfórico a 35%, em seguida, utilizou-se o sistema adesivo Adper Single Bond 2 (3M ESPE) de acordo com as instruções do fabricante. Posteriormente, os corpos-de-prova foram armazenados em água deionizada a 37°C por 24h, 6 meses e 1 ano. Dois dentes adicionais foram usados ​​para analisar as interfaces de união no MEV. Os dados foram submetidos a ANOVA três fatores em esquema de parcela subdividida e ao teste de Tukey (α = 0,05). Os resultados mostram que a Di diminuiu os valores de µTBS quando comparado as Da e Dh, independente do tempo de armazenamento ou tratamento. Amostras armazenadas por 6 meses e 1 ano diminuíram a µTBS para o grupo de controle, mas nenhuma diferença foi encontrada entre o tempo de armazenamento para o grupo CHX. A aplicação de CHX 2% após o condicionamento apresentou melhora na resistência de união à dentina no tempo de armazenamento, independente dos substratos avaliados.

Humans , Dental Bonding , Dentin-Bonding Agents , Tensile Strength , Materials Testing , Composite Resins , Resin Cements , Dentin
Rev. bras. med. esporte ; 27(2): 207-211, Apr.-June 2021. tab, graf
Article in English | LILACS | ID: biblio-1280070


ABSTRACT Introduction: Ischemic preconditioning (IPC) has been described in the literature as a resource capable of improving physical performance. Objective: The purpose of this randomized double-blind study was to evaluate the influence of IPC on the neuromuscular performance of trained individuals. Methods: Twenty-four (24) resistance training participants (6 of them women) with a mean age of 25.8 ± 4.6 years were selected and divided into two groups: the upper limb group (ULG) composed of 12 individuals (4 women) and the lower limb group (LLG) composed of 12 individuals (2 women). The maximum repetitions test was applied in the bench press for the ULG and in the 45° leg press for the LLG, with 50% of the one-repetition maximum under control, placebo and IPC conditions, at a random interval of 72 hours between tests. The IPC was applied four hours before the tests by means of an analog sphygmomanometer cuff inflated to 220 mmHg on the arm for the ULG and on the thigh for LLG, with three cycles of five minutes each of ischemia and reperfusion, alternating between the right and left sides. For the placebo, the cuff was inflated to 40 mmHg without causing ischemia. The significance level for the Wilcoxon test was p <0.017, due to the Bonferroni correction. The effect size (ES) was also analyzed. Results: With IPC, the ULG performed 34.8 ± 4.8 repetitions, representing an improvement of 11.29% (IPC vs. control, ES = 0.68 and p = 0.002) and the LLG performed 40.5 ± 15.7 repetitions, representing an improvement of 37.47% (IPC vs. control, ES = 0.84 and p = 0.002). No significant improvements were observed for the placebo in either group. Conclusion: Our data showed that IPC positively influenced neuromuscular performance of both the upper and lower limbs. Level of evidence II; Therapeutic studies investigating the results of treatment (Prospectived comparative studye).

RESUMEN Introducción: El preacondicionamiento isquémico (PCI) ha sido descrito en la literatura como un recurso capaz de mejorar el desempeño físico. Objetivo: El objetivo de este estudio aleatorio doble ciego fue evaluar la influencia del PCI en el desempeño neuromuscular de individuos entrenados. Métodos: Fueron seleccionados 24 individuos (6 mujeres) con promedio de edad de 25,8 ± 4,6 años, practicantes de entrenamiento resistido, divididos en dos grupos, siendo un grupo de miembros superiores (GMS) compuesto por 12 individuos (4 mujeres) y grupo de miembros inferiores (GMI) compuesto por 12 individuos (2 mujeres). El test de repeticiones máximas fue aplicado en el ejercicio de supino para el GMS y en el leg press 45° para el GMI con 50% de una repetición máxima, en las condiciones de control, placebo y PCI, de forma aleatoria con intervalo de 72 horas entre los tests. El PCI fue aplicado cuatro horas antes de los tests mediante un manguito de esfigmomanómetro analógico inflado a 220 mmHg en el brazo para el GMS y en el muslo para el GMI, siendo tres ciclos de cinco minutos de isquemia y cinco minutos de reperfusión, alternando los lados derecho e izquierdo. Para el placebo, el manguito quedó en 40 mmHg, sin provocar isquemia. El nivel de significancia del test de Wilcoxon fue p <0,017, debido a la corrección de Bonferroni. El tamaño del efecto (TE) también fue analizado. Resultados: Con el PCI, el GMS realizó 34,8 ± 4,8 repeticiones, representando mejora de 11,29% (PCI vs control, TE = 0,68 y p = 0,002) y el GMI realizó 40,5 ± 15,7 repeticiones, representando mejora de 37,47% (PCI vs control, TE = 0,84 y p = 0,002). Con el placebo, ambos grupos no mostraron mejora. Conclusión: Nuestros datos mostraron que el PCI influenció positivamente el desempeño neuromuscular tanto de miembros superiores como inferiores. Nivel de evidencia II; Estudios terapéuticos: investigación de los resultados del tratamiento (estudio comparativo prospectivo).

RESUMO Introdução: O pré-condicionamento isquêmico (PCI) tem sido descrito na literatura como um recurso capaz de melhorar o desempenho físico. Objetivo: O objetivo deste estudo randomizado duplo cego foi avaliar a influência do PCI no desempenho neuromuscular de indivíduos treinados. Métodos: Foram selecionados 24 indivíduos (6 mulheres) com média de idade de 25,8 ± 4,6 anos, praticantes de treinamento resistido, divididos em dois grupos, sendo um grupo de membros superiores (GMS), composto por 12 indivíduos (4 mulheres) e grupo de membros inferiores (GMI), composto por 12 indivíduos (2 mulheres). O teste de repetições máximas foi aplicado no exercício de supino para o GMS e no leg press 45° para o GMI com 50% de uma repetição máxima, nas condições de controle, placebo e PCI, de forma aleatória com intervalo de 72 horas entre os testes. O PCI foi aplicado quatro horas antes dos testes por meio de um manguito de esfigmomanômetro analógico inflado a 220 mmHg no braço para o GMS e na coxa para o GMI, sendo três ciclos de cinco minutos de isquemia e cinco minutos de reperfusão, alternando os lados direito e esquerdo. Para o placebo, o manguito ficou em 40 mmHg, sem provocar isquemia. O nível de significância do teste de Wilcoxon foi de p < 0,017, devido à correção de Bonferroni. O tamanho do efeito (TE) também foi analisado. Resultados: Com o PCI, o GMS realizou 34,8 ± 4,8 repetições, representando melhora de 11,29% (PCI vs. controle, TE = 0,68 e p = 0,002) e o GMI realizou 40,5 ± 15,7 repetições, representando melhora de 37,47% (PCI vs. controle, TE = 0,84 e p = 0,002). Com o placebo, ambos os grupos não apresentaram melhora. Conclusão: Nossos dados mostraram que o PCI influenciou positivamente o desempenho neuromuscular tanto de membros superiores quanto inferiores. Nível de evidência II; Estudos terapêuticos-Investigação dos resultados do tratamento (Estudo prospectivo comparativo).

Humans , Male , Female , Adult , Young Adult , Ischemic Preconditioning , Muscle Strength/physiology , Athletic Performance/physiology , Endurance Training/methods , Muscles/blood supply , Tensile Strength , Double-Blind Method , Exercise Test/methods
Rev. ADM ; 78(3): 149-154, mayo-jun. 2021. ilus, tab
Article in Spanish | LILACS | ID: biblio-1254699


Introducción: Las alternativas de tratamiento de órganos dentales con gran destrucción en su estructura varían, no sólo por el material de restauración, sino también por el valor económico y estético. Dentro de las alternativas existe: corona convencional, endocorona cuyo objetivo principal es la elaboración de una restauradora que evita la colocación de postes intraconducto y endocorona con ausencia de una pared axial (EPA) que se realiza cuando una pared, mesial, distal, vestibular o palatina está ausente. Objetivo: Verificar si la endocorona EPA se comporta de igual manera que las coronas convencionales y endocoronas al medir su resistencia ante fuerzas de tracción. Material y métodos: Treinta premolares fueron tratados endodóncicamente, 10 fueron preparados para recibir una corona convencional (grupo A), 10 para endocorona (grupo B) y 10 para endocorona EPA (grupo C). Se realizaron fuerzas de tracción para obtener el valor máximo en el cual las coronas fallaron. Se realizó una prueba ANOVA para comparar los resultados. Resultados: Al someter a los tres tipos de coronas a fuerzas de tracción los resultados obtenidos fueron: 3.04 ± 0.55 MPa para la corona, 7.08 ± 1.6 MPa para la endocorona y 6.17 ± 1.12 MPa para la endocorona EPA. Conclusiones: No existió diferencia significativa entre la endocorona (7.08 MPa) y la EPA (6.17 MPa), convirtiéndose en una alternativa de tratamiento con buen pronóstico en la práctica diaria (AU)

Introduction: The alternatives of treatment of tooth with excessive wear vary not only by the restoration material but also by the economic and aesthetic value. Among the alternatives there is: conventional crown, endocrown whose main objective is the elaboration of a restorative that avoids the placement of intraconducting posts and endocrown without one axial wall (EPA) that is done when a wall; mesial, distal, vestibular or palatal is absent. Objective: To verify if the (EPA) behaves in the same way as the conventional crown and endocrown when measuring its resistance to tensile strength. Material and methods: 30 premolars were treated endodontically, ten were prepared to receive a conventional crown, 10 for endocrown and 10 for EPA. Tensile strength were performed to obtain the maximum value at which the crowns failed, an ANOVA test was performed to compare the results. Results: When the three types of crowns were subjected to tensile strength, the results obtained were; 3.04 ± 0.55 MPa for the crown, 7.08 ± 1.6 MPa for the endocrown and 6.17 ± 1.12 MPa for the EPA endocrown. Conclusions: There was no significant difference between the endocrown (7.08 MPa) and EPA endocrown (6.17 MPa) becoming an alternative treatment with good prognosis in daily practice (AU)

Humans , Tensile Strength , Tooth, Nonvital/therapy , Crowns , Prognosis , Bicuspid , Ceramics , Analysis of Variance , Cementation/methods
Chinese Journal of Medical Instrumentation ; (6): 512-516, 2021.
Article in Chinese | WPRIM | ID: wpr-922049


OBJECTIVE@#A rapid fixation device is developed to solve the problems of emergency fixation and transportation of patients with spinal injury.@*METHODS@#Through the analysis of the function,3D modeling design, finite element analysis and optimization design based on ANSYS Workbench, tensile strength verification experiment, we produced the prototype, and tested it, conducted a simulated rescue experiment.@*RESULTS@#The fixation device designed can meet the demand of spinal injury patients for safe rescue after accidents, and the quality of the rapid fixation device was lighten by about 30% without reducing the intensity.@*CONCLUSIONS@#The method based on optimal design can obviously improve the structure design, and has reference significance for other related rescue equipment design.

Humans , Equipment Design , Finite Element Analysis , Tensile Strength