Artificial teeth obtained by additive manufacturing: Wear resistance aspects. A systematic review of in vitro studies.

Wear resistance is one of the properties that must be considered for maintaining the long-term functionality of artificial teeth in dental prostheses. This property can be altered by the method of tooth fabrication, the material, the chewing force, and the relationship to the antagonist tooth. This systematic review evaluated the wear resistance of artificial teeth obtained by the additive manufacturing method and aims to answer the question, "Do artificial teeth for dental prostheses obtained by additive manufacturing show wear resistance similar to prefabricated ones?" The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Checklist guidelines were followed with a customized search in Scopus, PubMed/Medline, Embase, Science Direct, and Google Scholar databases on August 30, 2023. The inclusion criteria were artificial teeth for dental prostheses in acrylic resin by additive manufacturing and comparing the wear resistance with conventional prefabricated teeth, in vitro and English studies, without time restriction. And excluded if 1) do not make artificial teeth by additive manufacturing or that were metal or ceramic teeth; 2) clinical trials, animal studies, review articles, case reports, letters to the editor, short communication, book chapters; 3) another language that is not English. The selection was in two steps, reading the titles and abstracts, followed by reading the selected studies in full. The risk of bias analysis was performed with the adaptation of the quasi-experimental studies tool by Joanna Briggs Institute. Four hundred and twelve articles were found in the databases, after the selection steps and application of eligibility criteria, 6 articles were included for qualitative data analysis and presented low risk of bias. For teeth obtained by additive manufacturing, 2 studies reported lower wear resistance, 2 studies had higher resistance, and 2 similar compared to prefabricated ones. Additive manufactured teeth compared to prefabricated teeth show influences on wear resistance due to differences in material composition, relationship to the antagonist's tooth, applied force, chewing cycles, and processing methods.

Analysis of Diffusion Coefficients of Iron Monoboride and Diiron Boride Coating Formed on the Surface of AISI 420 Steel by Two Different Models: Experiments and Modelling.

In the present work, two mathematical diffusion models have been used to estimate the growth of the iron monoboride and diiron boride coating formed on AISI 420 steel. The boronizing of the steel was carried out with the solid diffusion packing method at a boronizing temperature of 1123 K-1273 K. Experimental results show the two-coating system consists of an outer monoboride and an inner diiron boride coating with a predominantly planar structure at the propagation front. The depth of the boride coating increases according to temperature and treatment time. A parabolic curve characterizes the propagation of the boride coatings. The two proposed mathematical models of mass transfer diffusion are founded on the solution corresponding to Fick's second fundamental law. The first is based on a linear boron concentration-penetration profile without time dependence, and the second model with time dependence (exact solution). For both models, the theoretical law of parabolic propagation and the average flux of boron atoms (Fick's first fundamental law) at the growth interfaces (monoboride/diiron boride and diiron boride/substrate) are considered to estimate the propagation of the boride coatings (monoboride and diiron boride). To validate the mathematical models, a programming code is written in the MATLAB program (adaptation 7.5) designed to simulate the growth of the boride coatings (monoboride and diiron boride). The following parameters are used as input data for this computer code: (the layer thicknesses of the FeB and Fe2B phases, the operating temperature, the boronizing time, initial formation time of the boride coating, the surface boron concentration limits, FeB/Fe2B and Fe2B/Fe growth interfaces, and the mass transfer diffusion coefficient of boron in the iron monoboride and diiron boride phases). The outputs of the computer code are the constants εFeB and εFe2B. The assessment of activation energies of AISI 420 steel for the two mathematical models of mass transfer is coincident (QFeB=221.9 kJ∙mol-1 and QFe2B=209.1 kJ∙mol-1). A numerical analysis was performed using a standard Taylor series for clarification of the proximity between the two models. SEM micrographs exhibited a strong propensity toward a flat-fronted composition at expansion interfaces of the iron monoboride and diiron boride coating, confirmed by XRD analysis. Tribological characterizations included the Vickers hardness test method, pin-on-disc, and Daimler-Benz Rockwell-C indentation adhesion tests. After thorough analysis, the energies were compared to the existing literature to validate our experiment. We found that our models and experimental results agreed. The diffusion models we utilized were crucial in gaining a deeper understanding of the boronizing behavior of AISI 420 steel, and they also allowed us to predict the thicknesses of the iron monoboride and diiron boride coating. These models provide helpful approaches for predicting the behavior of these steels.

Effect of Recycled Polyvinyl Butyral (rPVB) Addition on the Tribological Performance of Glass-Fiber Reinforced Polyamide (PAGF) during Reciprocating Sliding Wear Conditions.

Plastic recycling in the automotive industry is a priority. In this study, the effect of adding recycled polyvinyl butyral (rPVB) from automotive windshields on the coefficient of friction (CoF) and specific wear rate (k) of a glass-fiber reinforced polyamide (PAGF) is investigated. It was found that, at 15 and 20 wt.% of rPVB, it acts as a solid lubricant, reducing CoF and k up to 27% and 70%, respectively. Microscopical analysis of the wear tracks showed that rPVB spreads over the worn tracks, forming a lubricant layer, which protects the fibers from damage. However, at lower rPVB content, fiber damage cannot be prevented as the protective lubricant layer is not formed.

Influence of TiO2 nanoparticles content as reinforce material to enhance the mechanical and corrosion resistance properties of Sn and Sn-Ag alloy for dental applications.

This study evaluated the influence of the TiO2 nanoparticles (NPs) on the mechanical and chemical performance of Sn and Sn-Ag alloys. The XRD (X-ray diffraction) and HR-TEM (high resolution-transmission electron microscopy) methods were used to characterize the NPs synthesized by the sol-gel microwave process. The chemical composition of the alloys was Sn, Sn+3TiO2 NPs, Sn-5Ag+1.5TiO2 NPs, Sn-10Ag, and Sn-10Ag+3TiO2 NPs, obtained from an experimental factorial design (EFD). A statistical model was used to determine the mechanical and chemical properties, showing the Vickers hardness response surface, tensile strength, wear, and corrosion resistance. The wear and corrosion tests for the various alloy compositions were performed using human artificial saliva solution. The results indicated that the Sn-10Ag+3TiO2 NPs exhibited the highest mechanical performance due to their increased hardness (380 HV), tensile strength (370 N), and wear resistance (0.34 × 10-3 mm3 Nm-1); in all the cases, the inclusion of TiO2 NPs enhanced the corrosion resistance of the alloys. According to the American Dental Association (ADA), Sn-10Ag+3TiO2 NPs alloy could be classified as a possible type IV restorative material.

Effects of Nb Additions and Heat Treatments on the Microstructure, Hardness and Wear Resistance of CuNiCrSiCoTiNbx High-Entropy Alloys.

In this research, a set of CuNiCrSiCoTi (H-0Nb), CuNiCrSiCoTiNb0.5 (H-0.5Nb) and CuNiCrSiCoTiNb1 (H-1Nb) high-entropy alloys (HEAs) were melted in a vacuum induction furnace. The effects of Nb additions on the microstructure, hardness, and wear behavior of these HEAs (compared with a CuBe commercial alloy) in the as-cast (AC) condition, and after solution (SHT) and aging (AT) heat treatments, were investigated using X-ray diffraction, optical microscopy, and electron microscopy. A ball-on-disc configuration tribometer was used to study wear behavior. XRD and SEM results showed that an increase in Nb additions and modification by heat treatment (HT) favored the formation of BCC and FCC crystal structures (CS), dendritic regions, and the precipitation of phases that promoted microstructure refinement during solidification. Increases in hardness of HEA systems were recorded after heat treatment and Nb additions. Maximum hardness values were recorded for the H-1Nb alloy with measured increases from 107.53 HRB (AC) to 112.98 HRB, and from 1104 HV to 1230 HV (aged for 60 min). However, the increase in hardness caused by Nb additions did not contribute to wear resistance response. This can be attributed to a high distribution of precipitated phases rich in high-hardness NiSiTi and CrSi. Finally, the H-0Nb alloy exhibited the best wear resistance behavior in the aged condition of 30 min, with a material loss of 0.92 mm3.

Effect of SiO2 and Al2 O3 nanoparticles on wear resistance of PMMA acrylic denture teeth / Efeito das nanopartículas de SiO2 e Al2 O3 na resistência ao desgaste de dentes em acrílico PMMA para prótese

Objetivo: Este estudo teve como objetivo avaliar a resistência ao desgaste de dentes em acrílico para próteses contendo nanopartículas de dióxido de silício (nano-SiO2 ) e dióxido de alumínio (nanoAl2 O3 ). Material e Métodos: O material em polimetilmetacrilato (PMMA) foi utilizado para fabricar 84 amostras (n=10) contendo nano-SiO2 e nano-Al2 O3 nas concentrações 0,1% em peso, 0,3% em peso e 0,5% em peso de pó acrílico. Uma máquina de teste de desgaste de dois corpos e um microscópio digital foram usados para medir as mudanças na perda de peso e rugosidade da superfície, respectivamente. Testes de ANOVA a um fator e testes de comparações múltiplas de Tukey foram utilizados para análise dos dados (α = 0,05). Resultados: O material modificado com nano-SiO2 demonstrou um aumento significativo na perda de peso em comparação com o material acrílico artificial convencional (p ˂ 0,05) enquanto o material modificado com nano-Al2 O3 demonstrou aumento não significativo na perda de peso, exceto no subgrupo 0,5% (p < 0,05). Não há diferenças significativas em relação à alteração da rugosidade após a simulação de desgaste entre todos os grupos testados (p > 0,05). Conclusão: As nanopartículas de nano-Al2 O3 exibem menos efeito negativo que o nanoSiO2 , podendo ser usado com cautela, se necessário. (AU)

Objective: This study aimed to evaluate the wear resistance of acrylic denture teeth containing silicon dioxide (nano-SiO2 ) and aluminum dioxide (nano-Al2 O3 ) nanoparticles. Material and Methods: Poly methyl methacrylate (PMMA) denture tooth material was used to denture tooth material was used to fabricate 84 specimens (n=10) containing nano-SiO2 and nano-Al2 O3 in concentrations 0.1wt%, 0.3wt%, and 0.5wt% of acrylic powder. A two-body wear testing machine and digital microscope were used to measure the changes in weight loss and surface roughness respectively. One-way ANOVA and pair-wise Tukey's post-hoc tests were used for data analysis (α = 0.05). Results: Nano-SiO2 modified teeth material demonstrated a significant increase in weight loss in comparison conventional artificial acrylic teeth material (p ˂ 0.05) while nanoAl2 O3 modified teeth material demonstrated non-significant increase in weight loss except for 0.5% subgroup (p ˂ 0.05). There is no significant differences regarding roughness change after wear simulation among all tested groups (p > 0.05). Conclusion: Nano-Al2 O3 nanoparticles exhibit less negative effect than nano-SiO2 so; it could be used with caution if necessary. (AU)

Nanotribological behavior of deep cryogenically treated martensitic stainless steel.

Cryogenic treatments are increasingly used to improve the wear resistance of various steel alloys by means of transformation of retained austenite, deformation of virgin martensite and carbide refinement. In this work the nanotribological behavior and mechanical properties at the nano-scale of cryogenically and conventionally treated AISI 420 martensitic stainless steel were evaluated. Conventionally treated specimens were subjected to quenching and annealing, while the deep cryogenically treated samples were quenched, soaked in liquid nitrogen for 2 h and annealed. The elastic-plastic parameters of the materials were assessed by nanoindentation tests under displacement control, while the friction behavior and wear rate were evaluated by a nanoscratch testing methodology that it is used for the first time in steels. It was found that cryogenic treatments increased both hardness and elastic limit of a low-carbon martensitic stainless steel, while its tribological performance was enhanced marginally.

High-Energy Dissipation Performance in Epoxy Coatings by the Synergistic Effect of Carbon Nanotube/Block Copolymer Conjugates.

Hierarchical assembly of hard/soft nanoparticles holds great potential as reinforcements for polymer nanocomposites with tailored properties. Here, we present a facile strategy to integrate polystyrene-grafted carbon nanotubes (PSgCNT) (0.05-0.3 wt %) and poly(styrene-b-[isoprene-ran-epoxyisoprene]-b-styrene) block copolymer (10 wt %) into epoxy coatings using an ultrasound-assisted noncovalent functionalization process. The method leads to cured nanocomposites with core-shell block copolymer (BCP) nanodomains which are associated with carbon nanotubes (CNT) giving rise to CNT-BCP hybrid structures. Nanocomposite energy dissipation and reduced Young's Modulus (E*) is determined from force-distance curves by atomic force microscopy operating in the PeakForce QNM imaging mode and compared to thermosets modified with BCP and purified carbon nanotubes (pCNT). Remarkably, nanocomposites bearing PSgCNT-BCP conjugates display an increase in energy dissipation of up to 7.1-fold with respect to neat epoxy and 53% more than materials prepared with pCNT and BCP at the same CNT load (0.3 wt %), while reduced Young's Modulus shows no significant change with CNT type and increases up to 25% compared to neat epoxy E* at a CNT load of 0.3 wt %. The energy dissipation performance of nanocomposites is also reflected by the lower wear coefficients of materials with PSgCNT and BCP compared to those with pCNT and BCP, as determined by abrasion tests. Furthermore, scanning electron microscopy (SEM) images taken on wear surfaces show that materials incorporating PSgCNT and BCP exhibit much more surface deformation under shear forces in agreement with their higher ability to dissipate more energy before particle release. We propose that the synergistic effect observed in energy dissipation arises from hierarchical assembly of PSgCNT and BCP within the epoxy matrix and provides clues that the CNT-BCP interface has a significant role in the mechanisms of energy dissipation of epoxy coating modified by CNT-BCP conjugates. These findings provide a means to design epoxy-based coatings with high-energy dissipation performance.

Study of PVD AlCrN Coating for Reducing Carbide Cutting Tool Deterioration in the Machining of Titanium Alloys.

The manufacture of medical and aerospace components made of titanium alloys and other difficult-to-cut materials requires the parallel development of high performance cutting tools coated with materials capable of enhanced tribological and resistance properties. In this matter, a thin nanocomposite film made out of AlCrN (aluminum-chromium-nitride) was studied in this research, showing experimental work in the deposition process and its characterization. A heat-treated monolayer coating, competitive with other coatings in the machining of titanium alloys, was analyzed. Different analysis and characterizations were performed on the manufactured coating by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDXS), and X-ray diffraction (XRD). Furthermore, the mechanical behavior of the coating was evaluated through hardness test and tribology with pin-on-disk to quantify friction coefficient and wear rate. Finally, machinability tests using coated tungsten carbide cutting tools were executed in order to determine its performance through wear resistance, which is a key issue of cutting tools in high-end cutting at elevated temperatures. It was demonstrated that the specimen (with lower friction coefficient than previous research) is more efficient in machinability tests in Ti6Al4V alloys. Furthermore, the heat-treated monolayer coating presented better performance in comparison with a conventional monolayer of AlCrN coating.

Evaluación del desgaste por cepillado, in vitro, de una resina compuesta, fotopolimerizada por lámpara halógena: en dos tiempos diferentes / Wear evaluation of the in vitro toothbrushing of a composite resin cured by halogent light curing: in two different times

El objetivo de este trabajo fue evaluar el desgaste abrasivo por cepillado in vitro de la resina compuesta 4Seasons, de dos colores diferentes (A3 y C4) y polimerizadas por dos diferentes tiempos (20 e 40 s), utilizando cepillo dental y dentífrico; también se uso como material de referencia, el PMMA. Fueron confeccionados 10 especímenes, para cada uno de los 5 grupos (PMMA, A3 20s, A3 40s, C4 20s, C4 40s). Después de su confección, cada espécimen era almacenado en agua desmineralizada a 37 ± 2 ºC, por 24 horas, regularizados con lija; después del lavado en ultrasonido, volvían a ser almacenados en las mismas condiciones por 7 días. El cepillado fue realizado en una máquina para desgaste por cepillado, aplicándose una carga de 3N, con frecuencia de 4,5 ciclos/seg; el período de cepillado de un espécimen comprendía 150,000 ciclos. Fueron realizados 5 lotes de cepillado, de modo que un espécimen de cada material de cada grupo fuese sometido a cada una de las posiciones ocupadas por los 10 cepillos. La cantidad de masa pérdida fue calculada por pesaje (pre y post cepillado). Este trabajo también fue ilustrado con gráficos de rugosidad y MEB. La tasa media de desgaste fue de 2,8 mg para PMMA, de 5,5 mg para A3-20s, 4,7 mg para A3-40 s, 5,4 para C4-20s y 4,2 mg para C4-40s. ANOVA mostro que no hubo diferencia significante entre los grupos, para p=0,166. Concluyéndose que no existió diferencia de resistencia al desgaste abrasivo entre los grupos

To evaluate abrasive wear, by weight changes, of a resin composite to in vitro toothbrushing, of two different colors (A3 and C4), cured by two times (20 and 40 s). Resin composite 4Seasons was material studied and PMMA was used as reference material. Ten cylindric samples had been prepared for each one of the five evaluated groups (PMMA, A3 20s, A3 40s, C4 20s, C4 40s). After confection, samples were immersed in deionized water, at 37± ºC, for 24 h, and then regularized by abrasive gritting with sandpaper, after that, were cleaned in ultrasound bath, and restored to the same described conditions, for 7 days. The toothbrushing was then conducted in a proper machine that holds 10 specimens, with 3 N load of each toothbrush on the respective sample using dentifrice and water. 150.000 cycles were applied per group. Five lots of toothbrushing had been performed; in a way that one sample of each group had been submitted to the brushing action at one position in the machine. The amount of weight loss for each sample was calculated by means of weighting. Roughness and MEV were also evaluated. Data were analyzed with one-way ANOVA. The average rate of wear was of 2.8 mg for PMMA, 5.5 mg for A3-20s, 4.7 mg for A3-40 s, 5.4 for C4-20s, and 4,2 mg for C4-40s. One-way ANOVA showed no significant difference between groups (p=0.166). It was possible to conclude that difference of the resistance to the abrasive wear between the studied groups did not exist

Avaliação do desgaste por escovação, in vitro, de uma resina composta, fotopolimerizada por lâmpada halógena, em dois diferentes tempos / In vitro toothbrushing wear evaluation of a resin composite cured by QTH curing unit in two different times

Um dos principais problemas dos materiais restauradores (incluindo a resina composta) é o desgaste por abrasão. Portanto, o objetivo neste trabalho foi avaliar in vitro o desgaste abrasivo por escovação da resina composta 4Seasons, de duas cores diferentes (A3 e C4) e com fotopolimerização por dois diferentes tempos (20 e 40 s), utilizando escova Sorriso, da Colgate, e creme dentifrício Colgate Tripla Ação; também foi usado, como material de referência, o polimetil metacrilato. Assim, foram confeccionados dez corpos-de-prova, para cada um dos cinco grupos formados (PMMA, A3 20s, A3 40s, C4 20s, C4 40s). Cada espécime consistia basicamente num cilindro de cerca de 1,8 mm de altura e 8 mm de diâmetro. Cada espécime, após sua confecção, era imerso em água deionizada, a 37 ± 2 ºC, por 24 horas, quando então eram regularizados com lixa (granulação # 600 e # 1.000); após lavagem com ultrassom, voltavam a ser armazenados nas mesmas condições, até completar-se um período de uma semana. A escovação foi então efetuada numa máquina própria, que comportava dez espécimes simultaneamente, sendo de 3 N a carga de cada escova sobre o respectivo espécime; a velocidade de cada escova era de 18 cm/s, com a freqüência (ida e volta, num percurso total de 4 cm) de 4,5 ciclos/s; o período de escovação de um espécime compreendia 150. 000 ciclos. Foram efetuados cinco períodos (ou lotes) de escovação, de modo que um espécime do material de cada grupo tivesse sido submetido à ação de cada uma das posições ocupadas pelas dez escovas.

A quantidade de massa perdida, para cada espécime, foi calculada por meio de pesagem (pré e pós escovação), numa balança com acuidade de milionésimo de grama. O trabalho foi também ilustrado com gráficos de rugosidade e com fotomicrografias tomadas ao MEV. A taxa média de desgaste foi de 2,8 mg para o PMMA, de 5,5 mg para o A3-20s, 4,7 mg para o A3-40 s, 5,4 para o C4-20s e 4,2 mg para o C4-40s; a respectiva análise de variância mostrou não existir diferença significante entre os grupos, para p=0,166; o coeficiente de variação entre os grupos foi bastante semelhante. Foi possível concluir que não existiu diferença da resistência ao desgaste abrasivo entre os grupos estudados.

One of the main problems of dental restorative materials (including the resin composites) is the abrasion wear. Therefore, the aim of this work was to evaluate in vitro the abrasive wear by toothbrushing of the resin composite 4Seasons, of two different colors (A3 and C4), cured by two different times (20 and 40 s), using a toothbrush (Sorriso - Colgate), and a dentifrice (Tripla Ação Colgate). Polimetil meth-acrylate was used as reference material. Ten cylindric samples (approximately 1.8 mm height and 8 mm diameter) had been prepared for each one of the five evaluated groups (PMMA, A3 20s, A3 40s, C4 20s, C4 40s). After confection, samples were immersed in deionized water, at 37 ± 2ºC, for 24 h, and then regularized by abrasive gritting with sandpaper (from #600 to # 1 000); after that, were cleaned in ultrasound bath, and restored to the same described conditions, until completing the period of one week. The toothbrushing was then conducted in a proper machine that holds 10 specimens simultaneously, with a 3 N load of each toothbrush on the respective sample. The speed of each toothbrush was of 18 cm/s, at a frequency of 4.5 cycles/s (each cycle consisting of 2 cm forward and 2 cm backward). 150. 000 cycles were applied per sample. Five periods (or lots) of toothbrushing had been performed, in a way that one sample of each group had been submitted to the brushing action at one position in the machine.

The amount of weight loss for each sample was calculated by means of weighting (before and after toothbrushing), in an analytical balance with accuracy of millionth of gram. Roughness and MEV photomicrographies were also evaluated. The average rate of wear was of 2.8 mg for PMMA, 5.5 mg for A3-20s, 4.7 mg for A3-40 s, 5.4 for C4-20s, and 4,2 mg for C4-40s. One-way ANOVA showed no significant difference between groups (p = 0.166). The coefficient of variation between the groups was sufficiently similar. It was possible to conclude that difference of the resistance to the abrasive wear between the studied groups did not exist.

In vitro wear resistance of three types of polymethyl methacrylate denture teeth

The wear resistance of denture teeth is important to the longevity of removable prostheses of edentulous patients. The ability of denture teeth to maintain a stable occlusal relationship over time may be influenced by this property. The purpose of this in vitro study was to evaluate the wear resistance of polymethyl methacrylate (PMMA) denture teeth based on their chemical composition when opposed by a ceramic antagonist. The maxillary canines (n=10) of 3 PMMA denture teeth (Trubyte Biotone, cross-linked PMMA; Trilux, highly cross-linked IPN (interpenetrating polymer network)-PMMA; and Vivodent, highly cross-linked PMMA) were secured in an in vitro 2-body wear-testing apparatus that produced sliding contact of the specimens (4.5 cycles/s, sliding distance of 20 mm, under 37°C running water) against glazed or airborne particle abraded ceramic. Wear resistance was measured as height loss (mm) under 300 g (sliding force) after 100,000 cycles, using a digital measuring microscope. Mean values were analyzed by 2-way ANOVA and Tukey’s test (á=0.05). The wear of Trubyte Biotone (0.93 ± 0.14 mm) was significantly higher than that of both other types of teeth tested against abraded ceramic (p<0.05). The Vivodent tooth (0.64 ± 0.17 mm) exhibited the best wear resistance among the denture teeth tested against airborne particle abraded ceramic. There were no statistically significant differences (p>0.05) in wear among the 3 denture teeth evaluated against glazed ceramic. Trilux and Vivodent teeth tested against either glazed or airborne particle abraded ceramic did not differ significantly from each other (p<0.05). All teeth showed significantly more wear against airborne particle abraded ceramic than against glazed ceramic (p<0.05). In conclusion, the three types of PMMA denture teeth presented significantly different wear resistance against the abraded ceramic. The high-strength PMMA denture teeth were more wear-resistant than the conventional PMMA denture tooth.

Analysis of the relationship between the surface hardness and Wear resistance of indirect composites used as veneer materials

This study evaluated the surface hardness and wear resistance of indirect composites (Artglass and Solidex) and the existence of a correlation between these properties. Twenty-four specimens (12 per material) were fabricated using a polytetrafluoroethylene matrix (5.0 mm in diameter; 7.0 mm high) following an incremental technique. Polymerization was done with a xenon stroboscopic light curing unit. After polishing, the specimens were stored in water at 37°C during either 1 day (n=6 per material) or 55 days (n=6 per material), after which Vickers surface hardness and wear resistance were assessed. Data were analyzed statistically by unpaired Student t-test, two-way ANOVA and Tukey's test. Surface hardness. Artglass had higher surface hardness than Solidex after 1-day immersion period (p<0.01), but after 55 days there was no significant difference between the materials (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p<0.01), while no significant difference was found between Solidex means (p>0.05). Wear resistance. Solidex had higher wear than Artglass after 1-day immersion period (p<0.01), but no significant difference was found between the materials after 55 days (p>0.05). Comparing the materials at both periods, Artglass means differed significantly to each other (p<0.01), with higher wear at 55-day period, but no difference was found between Solidex means (p>0.05). These results suggest that Artglass was better than Solidex in terms of hardness and wear resistance after 1-day water immersion. However, it was more susceptible to degradation, showing greater wear after 55 days. In conclusion, there was an inverse correlation between surface hardness and wear resistance for both Artglass and Solidex indirect composites, that is the higher the hardness, the lower the wear.

Este trabalho avaliou a dureza superficial e resistência à abrasão de duas resinas compostas indiretas (Artglass e Solidex) bem como a existência de correlação entre estas propriedades. Foram confeccionados 24 corpos-de-prova (12 de cada compósito) pela técnica incremental utilizando uma matriz de politetrafluoretileno. A polimerização foi feita usando uma unidade fotopolimerizadora com lâmpada estroboscópica de xenônio. Após polimento, os corpos-de-prova foram armazenados em água a 37°C durante períodos de 1 dia (n=6 por material) ou 55 dias (n=6 por material), após os quais a dureza superficial Vickers e a resistência à abrasão foram testadas. Os dados foram analisados estatisticamente por meio do teste t de Student não-pareado, ANOVA a dois critérios de classificação e teste de Tukey. A comparação entre os materiais para a dureza superficial demonstrou que, no período de 1 dia, Artglass teve maior dureza (p<0,01). No período de 55 dias não houve diferença estatisticamente significante entre os materiais (p>0,05). Comparando os materiais nos dois períodos, Artglass apresentou diferença estatisticamente significante (p<0,01), o que não foi observado para o Solidex (p>0,05). A comparação entre os materiais para a resistência à abrasão demonstrou que, no período de 1 dia, o Solidex teve maior desgaste (p<0,01) que o Artglass, enquanto no período de 55 dias não houve diferença significante (p>0,05). Comparando os materiais em ambos os períodos, houve diferença estatisticamente significante para o Artglass (p<0,01), com maior desgaste no período de 55 dias, mas não houve diferença significante para o Solidex (p>0,05). Esses resultados sugerem que o Artglass teve melhor desempenho que o Solidex quanto à dureza e resistência ao desgaste após 1 dia de imersão em água; porém, foi mais suscetível à degradação, com maior desgaste após 55 dias. Concluiu-se que houve correlação inversa entre dureza superficial e resistência ao desgaste para os compósitos...