Effect of various surface treatment methods on shear bond strength between acrylic denture teeth and thermoplastic nylon denture base.

PURPOSE: To evaluate the effect of mechanical, chemical, and mechanical-chemical surface treatment methods on shear bond strength between acrylic denture teeth and thermoplastic nylon denture base. MATERIALS AND METHODS: Maxillary central incisor teeth were treated with five different surface treatment methods: mechanical (sandblasting, T-shape diatoric holes), chemical (5% acetic acid solution, bonding agent), and mechanical-chemical (sandblasting + bonding agent) were embedded in thermoplastic nylon denture base (n = 10). A universal testing machine with a crosshead speed of 0.5 mm per minute was used to test the shear bond strength. Data obtained were statistically evaluated using one-way ANOVA and followed with Tukey post hoc test (α = 0.05) RESULTS: T-shaped diatoric holes exhibited significantly higher shear bond strength among the surface treatment groups, followed by sandblasting + bonding agent, sandblasting, bonding agent, and the acetic acid group (p < 0.001) CONCLUSION: T-shaped diatoric holes as a mechanical surface treatment showed higher shear bond strength than other methods.

Adhesion of Conventional, 3D-Printed and Milled Artificial Teeth to Resin Substrates for Complete Dentures: A Narrative Review.

BACKGROUND: One type of failure in complete or partial dentures is the detachment of resin teeth from denture base resin (DBR). This common complication is also observed in the new generation of digitally fabricated dentures. The purpose of this review was to provide an update on the adhesion of artificial teeth to denture resin substrates fabricated by conventional and digital methods. METHODS: A search strategy was applied to retrieve relevant studies in PubMed and Scopus. RESULTS: Chemical (monomers, ethyl acetone, conditioning liquids, adhesive agents, etc.) and mechanical (grinding, laser, sandblasting, etc.) treatments are commonly used by technicians to improve denture teeth retention with controversial benefits. Better performance in conventional dentures is realized for certain combinations of DBR materials and denture teeth after mechanical or chemical treatment. CONCLUSIONS: The incompatibility of certain materials and lack of copolymerization are the main reasons for failure. Due to the emerging field of new techniques for denture fabrication, different materials have been developed, and further research is needed to elaborate the best combination of teeth and DBRs. Lower bond strength and suboptimal failure modes have been related to 3D-printed combinations of teeth and DBRs, while milled and conventional combinations seem to be a safer choice until further improvements in printing technologies are developed.

The Effect of Salinized Nano ZrO2 Particles on the Microstructure, Hardness, and Wear Behavior of Acrylic Denture Tooth Nanocomposite.

The wear of acrylic denture teeth is a serious problem that can change the vertical dimensions of dentures. This study evaluates the effect of adding salinized nano ZrO2 particles on the microstructure, hardness, and wear resistance of acrylic denture teeth. Heat polymerizing polymethyl methacrylate resin was mixed with salinized ZrO2 at concentrations of 5 wt.% and 10 wt.%. Acrylic resin specimens without filler addition were used as a control group. SEM/EDS analyses were performed and the Vickers' hardness was evaluated. Two-body wear testing was performed using a chewing simulator with a human enamel antagonist. After subjecting the samples to 37,500 cycles, both height loss and weight loss were used to evaluate the wear behavior. The microstructural investigation of the reinforced-denture teeth indicates sound nanocomposite preparation using the applied regime without porosity or macro defects. The addition of zirconium oxide nanofillers to PMMA at both 5% and 10% increased the microhardness, with values of up to 49.7 HV. The wear mechanism in the acrylic base material without nanoparticle addition was found to be fatigue wear; a high density of microcracks were found. The addition of 5 wt.% ZrO2 improved the wear resistance. Increasing the nanoparticles to 10 wt.% ZrO2 further improved the wear resistance, with no microcracks found.

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)

Effect of experimental Ricinus communis solution for denture cleaning on the properties of acrylic resin teeth

This study evaluated Knoop hardness, surface roughness and color alteration of artificial teeth for dentures after immersion in water, 1 percent sodium hypochlorite and an experimental solution of 2 percent Ricinus communis (RC). Thirty specimens of Vipi, Biolux and Trilux were analyzed. Tests of Knoop hardness, surface roughness and color alteration were conducted immediately after specimen preparation (T0) and after two immersion protocols for 15 days (ΔT15) and 183 days (ΔT183). Data variation (ΔT) were subjected to ANOVA and Tukey's test (p<0.05). At ΔT15, Vipi presented hardness increase and Biolux presented the highest variation (p=0.01). RC caused the highest increase in hardness (p=0) and the lowest increase (p=0.005) in roughness. Biolux presented the lowest color alteration (p =0). At ΔT183, Trilux underwent the highest hardness variation (p=0). Biolux presented an increase in roughness (p=0). There was no significant differences in color alteration among the artificial teeth (p=0.06) and among solutions (p=0.08) after 183 days of immersion. All solutions (distilled water, 1 percent sodium hypochlorite and 2 percent RC) caused alterations on the analyzed properties. Both immersion protocols caused alterations on the analyzed properties.

Este estudo avaliou a dureza Knoop, rugosidade e alteração de cor de dentes artificiais após imersão em água, hipoclorito de sódio 1 por cento e solução de Ricinus communis 2 por cento (RC). Trinta espécimes de dentes das marcas Vipi, Biolux e Trilux foram analisados. Os testes de dureza, rugosidade e alteração de cor foram realizados após a obtenção dos espécimes (T0) e após dois protocolos de imersão nas soluções por 15 dias (Δ15) e 183 dias (Δ183). A variação dos dados (ΔT) foi submetida à ANOVA e teste de Tukey (p<0,05). Em ΔT15, Vipi apresentou aumento da dureza e Biolux, a maior variação (p =0,01). RC causou o maior aumento na dureza (p=0). RC causou o menor aumento na rugosidade (p=0,005). Biolux apresentou a menor alteração de cor (p=0). Em ΔT183, Trilux apresentou a maior variação na dureza. (p=0). Biolux apresentou aumento na rugosidade (p=0). Não houve diferença significante na alteração de cor entre dentes (p=0,06) e entre soluções (p=0,08) após 183 dias de imersão. Todas as soluções (água destilada, hipoclorito de sódio 1 por cento e RC) causaram alterações nas propriedades analisadas. Ambos os protocolos de imersão causaram alterações nas propriedades analisadas.

Estudo da resistência de união entre dentes de resina acrílica e bases de resina acrílica ativada termicamente por energia de microondas e poliamida em função de duas alturas de recobrimento cervical / Study of bond strength between acrylic resin teeth and acrylic resin bases thermally activated by microwave energy and polyamide according to two heights covering cervical

Esta pesquisa avaliou a resistência de união entre dentes de resina acrílica, uma base de RAAT e uma base de poliamida. Os corpos de prova foram preparados e divididos em seis grupos: quatro de poliamida e dois de resina acrílica ativada por microondas, que foi utilizada como controle. O teste de cisalhamento em 45º, foi feito em uma máquina de testes universal. Realizamos a análise dos dados através do teste não paramétrico de Kruskal-Wallis para comparação das medianas e o teste de comparações múltiplas de Dunn. As medianas de adesão variaram de 6,96 a 27,54Kgf. As maiores médias foram encontradas nos grupos controle (CB=28,89 e CI=14,23Kgf), no entanto, na maioria dos corpos de prova estudados não houve separação entre os dentes e a base de poliamida, em razão das características flexurais deste material.

This study investigated the bond strength between acrylic resin teeth, a polyamide base and a microwave polymerized acrylic resin denture bases. The specimens were prepared and divided in six groups: four of polyamide and two of acrylic resin, used as a control. A shear test was conducted in 45º, in an universal testing machine. Data were analysed using Kruskal-Wallis and multiple comparison Dunn’s test. The mean bond strength ranged from 6,96 to 27,54Kgf. Control group showed the greatest bond strength (CB=28,89 e CI=14,23Kgf), although in the great majority of the tested groups, there was no separation between the resin teeth and the polyamide base, due to flexural proprieties of this...