Influência de espessuras de fibromucosa e de material reembasador de próteses totais na distribuição de tensões sobre implantes cone morse durante fase de osseointegração: análise pelo método dos elementos finitos - 3D / Influence of fibromucosal thickness and reline material of complete dentures on stress distribution on cone morse implants during osseointegration phase: analysis by the finite element method - 3D

Durante o período de osseointegração de implantes em uma reabilitação oral com prótese do tipo protocolo ou overdenture, uma prótese total convencional provisória poderá ser utilizada e revestida com materiais reembasadores macios, os quais têm por objetivo reduzir o estresse para a interface ossoimplante. A avaliação mecânica de tal situação clínica é de extrema relevância, a fim de se estabelecer protocolos mais seguros durante esta fase inicial da implantodontia. O objetivo deste estudo foi realizar uma análise biomecânica pelo método dos elementos finitos 3D, da distribuição de tensões durante a fase provisória de reabilitação com implantes osseointegrados simulando uma situação clínica de protocolo/overdenture inferior sobre 4 implantes do tipo cone morse, na fase de cicatrização. Para este estudo foram confeccionados 6 modelos 3D, sob carregamento em 2 direções (vertical e oblíquo em relação ao plano oclusal), simulando osso tipo II, variando a altura do tecido gengival (2 mm e 3 mm) e a espessura do material reembasador (0 mm - sem material, 2 mm e 4 mm), sendo utilizado um cicatrizador compatível com a altura + 0,5 mm para cada situação gengival. A posição dos 4 implantes cone morse (UNITITE, UCM 3510N, SIN) foi sempre a mesma, nas posições perdidas dos dentes 46, 43, 33 e 36. Para a altura gengival de 2 mm foi utilizado cicatrizador de 2,5 mm de altura (UNITITE, CIMU 4525, SIN) e para a altura gengival de 3 mm, o cicatrizador de 3,5 mm de altura (UNITITE, CIMU 4535, SIN). Os modelos utilizados foram: (G2C2,5-SR) altura gengival de 2mm, cicatrizador de 2,5mm, sem material reembasador; (G2C2,5-R2) altura gengival de 2mm, cicatrizador de 2,5mm, com soft rreembasador de 2mm; (G2C2,5-R4) altura gengival de 2mm, cicatrizador de 2,5mm, com material reembasador de 4mm; (G3C3,5-SR) altura gengival de 3mm, cicatrizador de 3,5mm, sem material reembasador; (G3C3,5-R2) altura gengival de 3mm, cicatrizador de 3,5mm, e reembasador de 2mm e (G3C3,5-R4) altura gengival de 3mm, cicatrizador de 3,5mm e soft reembasador de 4mm. A metodologia para modelagem se baseou em um escaneamento de superfície de uma prótese total inferior montada, sob um modelo inferior padrão, e de seu modelo de assentamento. As geometrias dos implantes (CM 3,5x10mm) e de seus cicatrizadores foram obtidas por simplificação do desenho dos mesmos no programa SolidWorks e no programa Rhinoceros 3D. O software utilizado para análise foi o ANSYS 17.0. A visualização dos resultados foi qualitativa através de mapas de deslocamento, von Mises e tensão máxima principal. As regiões com maiores deslocamentos foram as dos implantes mais anteriores (#33 e #43), sendo os do modelo 6 submetidos a forças verticais os que apresentaram maiores deslocamentos, próximos a 0,05 mm. A força oblíqua, de forma geral, tendeu a sobrecarregar mais os implantes do lado onde as cargas foram aplicadas. No tecido ósseo foi possível observar que o osso cortical se mostrou com mais concentração de tensão de tração que o osso trabecular. A utilização do material reembasador gerou menores tensões transmitidas para o tecido gengival, concentrando estas tensões principalmente no material reembasador. A não utilização de material reembasador aumenta as concentrações de tensões nos implantes/cicatrizadores, independentemente de sua espessura ou da espessura gengival. Concluiu-se que o uso de reembasador soft diminuiu as tensões nos implantes/cicatrizadores e tecido gengival; o aumento da espessura do material reembasador não influenciou na diminuição das tensões aos tecidos de suporte e tecidos gengivais mais espessos foram favoráveis em diminuir as tensões transmitidas ao tecido ósseo, mas concentram mais tensões nos implantes/cicatrizadores(AU)

During the period of osseointegration of implants in an oral rehabilitation with a protocol or overdenturetype prosthesis, a conventional temporary complete denture can be used and coated with soft reline materials, which aim to reduce the stress to the bone-implant interface. The mechanical assessment of such a clinical situation is extremely relevant in order to establish safer protocols during this initial phase of implantology. The objective of this study was to perform a biomechanical analysis by the 3D finite element method, of the stress distribution during the provisional phase of rehabilitation with osseointegrated implants simulating a clinical situation of protocol/lower overdenture on 4 cone morse implants, in the healing phase. For this study, 6 3D models were made, under loading in 2 directions (vertical and oblique in relation to the occlusal plane), simulating type II bone, varying the height of the gingival tissue (2 mm and 3 mm) and the thickness of the reline material (0 mm - without material, 2 mm and 4 mm), using a healer compatible with the height + 0.5 mm for each gingival situation. The position of the 4 cone morse implants (UNITITE, UCM 3510N, SIN) was always the same, in the missing positions of teeth 46, 43, 33 and 36. For the 2 mm gingival height, a 2.5 mm high healer was used. (UNITITE, CIMU 4525, SIN) and for a gingival height of 3 mm, the healer with a height of 3.5 mm (UNITITE, CIMU 4535, SIN). The models used were: (G2H2,5-WS) 2mm gingival height, 2.5mm healing, without soft material; (G2H2,5-S2) 2mm gingival height, 2.5mm healing, with 2mm reline; (G2H2,5-S4) 2mm gingival height, 2.5mm healing, with 4mm reline; (G3H3,5-WS) gingival height of 3mm, healing of 3.5mm, without soft material; (G3H3,5-S2) 3mm gingival height, 3.5mm healing, and 2mm reline and (G3H3,5-S4) gingival height of 3mm, healing of 3.5mm and reliner of 4mm. The methodology for modeling was based on a surface scan of a complete lower denture assembled, under a standard lower model, and its seating model. The geometries of the implants (CM 3.5x10mm) and their healers were obtained by simplifying their design in the SolidWorks program and in the Rhinoceros 3D program. The software used for analysis was ANSYS 17.0. The visualization of the results was qualitative through displacement maps, von Mises and maximum principal stress. The regions with the greatest displacements were those of the most anterior implants (#33 and #43), and those of model 6 submitted to vertical forces presented the greatest displacements, close to 0.05 mm. The oblique force, in general, tended to place more stress on the implants on the side where the loads were applied. In the bone tissue, it was possible to observe that the cortical bone showed a higher concentration of tensile stress than the trabecular bone. The use of soft material generated lower tensions transmitted to the gingival tissue, concentrating these tensions mainly in the soft material. The non-use of soft material increases stress concentrations on implants/healers, regardless of their thickness or gingival thickness. It was concluded that the use of a soft reliner reduced the stresses on the implants/healers and gingival tissue; the increase in the thickness of the reline material did not influence the reduction of tensions to the supporting tissues and thicker gingival tissues were favorable in reducing the tensions transmitted to the bone tissue, but concentrated more tensions in the implants/healing agentes(AU)

Comparative Study on Color Stability of Denture Reline Polymers when Using Microwave and Chemical Disinfection

This study investigated the color stability of reline resin after two methods of disinfection i.e microwave disinfection and chemical disinfection. A stainless steel moldwith a breakaway compartment (10 mm in diameter by 0.7 mm thickness) was made to fabricate specimens of various resins. Each material was mixed according to manufacturer’s instructions and applied into the mold. Prior to color stability testing, specimenswere cleaned in distilled water for 20 minutes to kill any microorganisms that may had contaminated the discs during fabrication. And then specimens were immersed in Sodium Perborate Monohydrate 200 ml of solution for 15 days and microwaved for 15 days sothat it is comparable to chemical disinfection soaking. The color stability of each specimen was measured again using spectrophotometer and values were obtained. The data of ∆E, ∆L, ∆b, ∆a were analysed by 2 way repeated measures ANOVAs test. Significant statistic changes in color parameters ∆L, ∆a, ∆b of the reline resin DPI, Ufi Gel Hard And Kooliner were observed when dentures were disinfected by Sodium Perborate Monohydrate 2% solutions. The color stability of the reline resin was influenced by time, regardless of disinfection or non disinfection. This can be attributed to bleaching (whitening) effect of reline material. Discoloration Original Research Article of resin based materials may be caused by intrinsic or extrinsic factors. Intrinsic factors are related to internal alterations in material resulting from physicochemical reactions or residual monomer oxidation with time. Thus the initiator, quantity and type of monomer and the polymerisation efficiency can affect the color stability of resin based materials. The color stability deviation value ∆E significantly increased to maximum for chemical disinfectant, least for Control group and intermediate for microwaved group. Ufi Gel showed the highest deviation ∆E and Control Group showed the lowest deviation according to results

Relining of removable dentures: a literature review

Introduction: The alveolar bone resorption that occurs after tooth loss leads to maladaptation of prostheses over the mucosa, causing discomfort to the patient. However, these maladaptations can be solved by prosthesis relining. Objective: The aim of this study was to discuss based on the literature, the relining of complete and partial removable dentures. Literature review: Dentistry makes use of relining materials that can be either rigid or resilient, having a temporary or permanent characteristic. However, to obtain a satisfactory result, the knowledge of their indications, contraindications, advantages, disadvantages is required, in addition to the characteristics and types of materials. Patients should be aware of the importance of constant monitoring, or even the need to reline their dentures, as it is not possible to determine the biological tolerance of each individual. Conclusion: The installation and proservation phases become essential to minimize bone resorption, and also to achieve rehabilitative treatment success.

Avaliação in vitro da biocompatibilidade de resinas acrílicas para base de próteses e materiais reembasadores resilientes / In vitro biocompatilibility of denture base acrylic resins and soft reline materials

O objetivo deste estudo foi avaliar a citotoxicidade de 3 resinas acrílicas (RA) para bases de prótese sendo duas polimerizadas por energia de microondas (Vipi Wave-VW e Nature Cryl-NC) e uma fotoativada (Eclipse-E); e a biocompatibilidade de materiais reembasadores resilientes (MRR), sendo 2 à base de silicone (Ufi Gel P e Sofreliner S), 2 à base de resina acrílica (Durabase Soft e Trusoft) e 2 condicionadores de tecidos (Softone e Coe Comfort) por meio de análises do metabolismo celular, da morfologia celular, do padrão de morte celular, da proliferação celular e da expressão do fator de crescimento TGFß 1, da integrina α5ß1 e de citocinas. A análise das RA foi realizada com células L929; para os MRR, as análises foram realizadas utilizando-se células L929, e/ou HaCaT e/ou RAW 264,7. Os resultados obtidos foram submetidos à análise estatística, realizada ao nível de significância de 5%. Todos os materiais quando testados com eluatos não apresentaram efeitos citotóxicos, e quando testados em contato direto (MTT e azul de alamar) alteraram significativamente a viabilidade celular, tendo sido os menores valores observados para o material NC quando comparado ao E. Para os materiais reembasadores o T, S e C. Maior taxa de necrose e apoptose foram observadas para os eluatos de todos os materiais quando avaliados no período de 24 horas; além disso, foi demonstrado que os materiais avaliados podem desencadear a expressão do TGFß 1, da integrina α5ß1 e de proteínas inflamatórias (fator de necrose tumoral - TNF-α, da citocina IL-1ß e de 5 quimiocinas: CCL2, CCL3, CCL5, CXCL2 e CXCL4). Sendo assim, de acordo com as limitações do presente estudo, pode-se concluir que a resina Nature Cryl resultou em menor viabilidade celular que a resina Eclipse e que os materiais Ufi Gel P e Sofreliner S apresentaram, em geral, melhor bicompatibilidade dentre os materiais reembasadores resilientes avaliados

The aim of this study was to evaluate the cytotoxicity of 3 denture base acrylic resins with different polymerization methods (Eclipse, Vipi Wave and Nature Cryl) and the biocompatibility of soft lining materials, 2 silicone-based (Ufi Gel P and Sofreliner S), 2 acrylic-based (Durabase Soft and Trusoft) and 2 tissue conditioners (Softone and Coe Comfort), by analysing cell metabolism, cell morphology, pattern of cell death, cell proliferation and expression of growth factor TGFß 1, integrin α5ß1 and cytokines. For the acrylic resins, analyses were made with L929 cells, while for the resilient lining materials, analyzes were performed using L929, and/or HaCaT and/or RAW 264.7 cells. Results were statistically analyzed, at a significance level of 5%. The 24 and 48-h eluates from all materials were not cytotoxic to the cells. For the direct contact tests (MTT and Alamar Blue), a significant effect on cell viability was found, with the lowest values observed for materials NC when compared with E and between the reliners Trusoft, Softone and Coe Comfort. For all materials, increased rate of necrosis and apoptosis were observed for the 24 hs eluates. It was also demonstrated that all materials tested can trigger the expression of TGFß 1, α5ß1 integrin and inflammatory proteins (tumor necrosis factor -TNFα, cytokine IL-1ß and 5 chemokines- CCL2, CCL3, CCL5, CXCL2 and CXCL4). Thus, within the limitations of this study, it can be concluded that the denture base acrylic resin Nature Cryl resulted in lower cell viability compared to the Eclipse resin and that the materials Ufi Gel P and Sofreliner S showed better biocompatibility among the soft liner materials evaluated

The effect of bur preparation on the surface roughness and reline bond strength of urethane dimethacrylate denture base resin.

Background: The clinical success of relining depends on the ability of reline resin to bond to denture base. Surface preparations may influence reline bond strength of urethane-based dimethacrylate denture base resin. Aim: To investigate the effect of bur preparation on the surface roughness (R a ) of eclipse denture base resin and its shear bond strength (SBS) to an intra-oral self-curing reline material. The mode of reline bonding failure was also examined. Materials and Methods: Twenty-four cylindrical Eclipse™ specimens were prepared and separated into three groups of eight specimens each. Two groups were subjected to mechanical preparation using standard and fine tungsten carbide (TC) burs and the third group (control) was left unprepared. The R a of all specimens was measured using a contact stylus profilometer. Subsequently, relining was done on the prepared surface and SBS testing was carried out a day later using a universal testing machine. Results: One-way ANOVA revealed significant differences (P<0.05) in R a and SBS values for all the groups. Post-hoc Tukey's HSD test showed significant differences (P<0.05) between all the groups in the R a values. For SBS also there were significant differences (P<0.05), except between standard bur and control. Conclusions: 1) There was a statistically significant difference in the R a of Eclipse™ specimens prepared using different carbide burs (P<0.05). 2) There was a statistically significant difference in the relined SBS (P<0.05) when prepared using different burs, but the difference between the standard bur and the control group was not statistically significant.

Efeito da termociclagem sobre a rugosidade de reembasadores resilientes / Effect of thermocycling on surface roughness of soft denture liners

Objetivo: Este estudo buscou avaliar o efeito do armazenamento em água e da termociclagem sobre a rugosidade de reembasadores resilientes. Material e método: Quatro reembasadores resilientes (Ufi-gel P, Dentuflex, Trusoft e Dentusoft) foram selecionados. Os materiais foram preparados de acordo com as instruções dos fabricantes e colocados em matrizes vazadas com 20 mm de diâmetro e 5 mm de espessura. Cinco corpos de prova de cada resina foram fabricados e a rugosidade superficial (Ra) foi avaliada de acordo com os seguintes grupos experimentais: GC (grupo controle): imediatamente após a confecção das amostras; GA: após armazenamento em água destilada a 37 °C por 24 horas; GT: após termociclagem. Os resultados foram submetidos à análise de variância de dois fatores, seguida do teste de Tukey (a = 0,05). Resultado: A resina Ufigel P apresentou menores valores de rugosidade (p = 0,000368) em relação aos outros materiais. No período inicial de avaliação (GC) e após 24 horas de armazenamento em água (GA), não houve alteração da rugosidade para todos os materiais testados (p > 0,05). Após a termociclagem, houve aumento significativo da rugosidade apenas para o reembasador Dentusoft (p = 0,000368). Conclusão: A ciclagem térmica aumentou os valores de rugosidade para a resina Dentusoft, não havendo qualquer alteração para os demais materiais.

Purpose: This study evaluated the effect of storage in water and thermocycling on roughness of reline materials. Material and method: Four reline materials (Ufi-gel P, Dentuflex, Trusoft and Dentusoft) were selected. The materials were prepared according to the manufacturers' instructions and were placed in stainless steel moulds (20 mm in diameter and 5 mm thick). Five samples of each resin were made (n = 5) and roughness (Ra) analyses according to the following experimental conditions: GC (control group): immediately after specimen preparation; GA: after storage in distilled water at 37 °C for 24 hours; GT: after thermocycling. Data were submitted to 2-way ANOVA followed by Tukey's test (a = 0.05). Result: Ufigel P resin had smaller surface roughness values (p = 0.000368) than the other ones. The initial period of evaluation (GC) and storage in water (GA) did not change roughness of the tested materials (p > 0.05). There was a significant increase in roughness after thermocycling only for Dentusoft (p = 0.000368). Conclusion: Thermocycling increased the roughness of the Dentusoft, with no change to the other materials.

Effect of microwave postpolymerization treatment on residual monomer content and the flexural strength of autopolymerizing reline resin.

Background : Microwave postpolymerization has been suggested as a method to improve the flexural strength of an autopolymerizing denture reline resin. However, the effect of microwave postpolymerization on the residual monomer content and its influence on flexural strength have not been investigated. Objectives : This study analyzed the effect of microwave postpolymerization on the residual monomer content and its influence on the flexural strength of an autopolymerizing reline resin (Denture Liner). Materials and Methods : A total of 70 specimens (64 Χ 10 Χ 3.3 mm) were polymerized according to the manufacturer's instructions and divided into 7 groups (n = 10). Control group specimens were not subjectedto any further processing. Before testing, the specimens were subjected to postpolymerization in a microwave oven using different power (550 and 650 W) and time (3, 4, and 5 min) settings. Two specimens of each group were then manually ground into fine powder and samples extracted from the specimens using reflux method. The samples were then subjected to gas chromatography for residual monomer determination in area%. Eight specimens were subjected to a three-point bending device with a span of 50 mm and crosshead speed of 5 mm/min, and the flexural strength was determined in MPa. Data analyses included Student's t-test and one-way analysis of variance. Results : For the Denture Liner reline resin, the residual monomer content decreased and the flexural strength increased significantly with the application of microwave irradiation using different time/power combinations. The specimens with the lowest residual monomer content were the similar specimens which presented with the highest flexural strength. Conclusion : Microwave postpolymerization irradiation can be an effective method for increasing the flexural strength of denture liner (at 650 W for 5 min) by reducing the residual monomer content by further polymerization at free radical sites.

Avaliação in vitro da citotoxidade de resinas acrílicas para reembasamento baseadas em uma nova formulação / In vitro cytotoxicity evaluation of reline acrylic resins based on new formulation

O objetivo deste estudo foi determinar a citotoxicidade in vitro de duas resinas reembasadoras experimentais autopolimerizáveis contendo alta concentração de agentes de ligação cruzada, etilenoglicol dimetacrilato (EGDMA) e 1,4-butanodiol dimetacrilato (BDMA) comparadas com uma resina reembasadora comercial (Tokuyama Rebase Fast II). Foram confeccionados corpos-de-prova em forma de discos das três resinas acrílicas reembasadoras rígidas sob condições assépticas. Os fibroblastos (L929) foram cultivados em placas com 96 compartimentos e incubadas por 24 h em meio de cultura Eagle. Os extratos foram preparados, colocando-se três amostras de cada resina em frascos de vidro estéreis com 9 mL de meio de Eagle e incubadas a 37º C por 24 h. O efeito citotóxico dos extratos foram avaliados utilizando os testes de incorporação do 3 H-timidina e MTT, que refletem os níveis de síntese de DNA e metabolismo celular, respectivamente. Os dados foram analisados estatisticamente, utilizando análise de variância (P<0.05). Para o teste de incorporação do 3 H-timidina, não foram observadas diferenças significativas (P>0.05) entre os materiais. A média da quantidade do isótopo incorporado no DNA celular para todas as resinas acrílicas foi estatisticamente menor do que para o controle. Todas as resinas acrílicas foram classificadas pelo teste de incorporação do 3 Htimidina como moderadamente citotóxicas. Da mesma forma, para o teste do MTT, não foi encontrada diferença significativa para a citotoxicidade entre os materiais (P>0.05). Quando a citotoxidade foi comparado com o grupo controle, todas as resinas foram classificadas entre não citotóxicas e discretamente citotóxicas pelo teste do MTT. Assim, conclui-se que a incorporação dos agentes de ligação cruzada, EGDMA e BDMA não influenciaram significativamente sobre a citotoxicidade observada. Não houve diferença entre a viabilidade celular para os materiais avaliados em ambos os testes

The aim of this study was to determine the cytotoxicity in vitro of two trials autopolymerizing reline systems made with higher concentration of cross-linking agents, EGDMA and BDMA compared to a commercial reline resin. Sample disks of the three hard reline acrylic resins were fabricated under aseptic conditions. The Fibroblast L929 cells were cultured in 96-well plates and incubated for 24 h in Eagle's medium. Eluates were prepared by placing three samples into a sterile glass vial with 9 mL of Eagle's medium and incubating at 37ºC for 24 h. The cytotoxic effect from the eluates was evaluated using the 3H-thymidine incorporation and MTT assays, which reflect DNA synthesis levels and cell metabolism, respectively. The data were statistically analyzed by using the one-way analysis of variance (P<.05). With the 3H-thymidine incorporation assay, no significant differences (P > .05) were found between the materials. The mean quantity of isotope incorporated into cellular DNA for all acrylic resins was statistically smaller than for the control. All acrylic resins were graded by the 3Hthymidine incorporation assay as moderate cytotoxic. Similarly, with the MTT assay, no significant difference in cytotoxicity was found between the materials (P > .05). When the cytotoxicity was compared with control group, all resins assay were between non cytotoxic and slight cytotoxic by the MTT. The incorporation of cross-linking agents, EGDMA and BDMA had no significant influence on the cytotoxicity observed. There was no cell viability difference between all materials in both assays.

The color stability of direct denture reline resins / 대한치과보철학회지

STATEMENT OF PROBLEM: Direct denture reline resins tend to discolor during service in the oral environment by intrinsic and extrinsic factor. PURPOSE: This study was designed to evaluate the color stability of direct denture reline resins. MATERIAL AND METHODS: Mild Rebaron(GC Corp., Japan), Meta Base M(Sun medical Co., Japan), Mild Rebaron LC(GC Corp., Japan) and as a control group, Vertex SC(Dentimex Zeist, Holland) were chosen for this study. Ten specimens of each direct denture reline resins were fabricated. Treatment methods designed for this study were the coffee staining test(7days) and the accelerated aging test(100hours). The color changes before and after treatment were measured by Tristimulous colorimeter(Yasuda seiki seisakusho, Ltd. Japan) and analyzed. RESULTS: All the direct denture reline resins subjected to the coffee staining test and the accelerated aging test showed noticible difference in color change. After coffee staining test, Meta Base M showed the highest color change followed by Vertex SC, Mild Rebaron LC and Mild Rebaron. There were no statistical differences between Meta Base M and Vertex SC and between Mild Rebaron LC and Mild Rebaron(p>0.05). After accelerated aging test, Mild Rebaron LC showed the highest color change followed by Vertex SC, Meta Base M and Mild Rebaron. There were no statistical differences only between Mild Rebaron and Mata Base M(p>0.05) but among the others, there were statistical differences(p<0.05). CONCLUSION: Within the limitation of this study, all the direct denture reline resins subjected to the extrinsic and intrinsic factors showed noticible difference in color change, and there were differences among manufacturers.

The effect of denture cleansers on the bond strength and the surface hardness of reline resin to denture base resin / 대한치과보철학회지

STATEMENT OF PROBLEM: Removable partial denture and complete denture often require denture base relines to improve the fittness against tissue-bearing mucosa because of the gradual change in edentulous ridge contour and resorption of underlyng bony structure. Self-curing hard reline resins offers the immediate and relatively inexpensive means to be recondition the surface of denture base directly. However weak bond between denture base resin and reline material can harbor bacteria, promote staining, or result in complete separation of the two materials. PURPOSE: The purpose of this study was to evaluate the effect of denture cleansers on bond strength and surface hardness of reline resin to denture base resin Denture base resin beams(60.0x15.0x3.0 mm) were made with Lucitone 199. MATERIAL AND METHODS: 10mm section was removed from the center of each specimen. The samples were replaced in the molds and the space of 10mm sections were packed with Tokuso Rebase reline material. The specimens were immersed in denture cleansers(Polident, Cleadent) and were evaluated after 1week, 2weeks, and 4weeks. The bond strength and surface hardness of self-curing hard reline materials to heat-curing denture base resin were measured using an UTM(universal testing machine). RESULTS AND CONCLUSION: 1) There was no significant difference of usage, kind, and denture cleaner by application time on the bonding strength of self-curing hard reline resin to denture base resin. 2) There was no significant difference of usage, kind, and denture cleaner by application time on the surface hardness, but the surface hardness showed decreasing tendency, as the time of immersion was extended 3) The failure modes of the specimens was initially adhesive failure and finally cohesive failure of self-curing hard reline resin.

A Study on the Bond Strength of Reline Resin to Pressure Injection Type Thermoplastic Denture Base Resin / 대한치과보철학회지

The purpose of this study was to evaluate the bond strength of reline resin to pressure injection type thermoplastic denture base resin.The denture base resins used in this study were Hipolycarbonate(High Dental Co.,Japan),Acetal dental(Pressingdental s.r.l.,Repubblica di San Marino)of thermoplastic resin and Acron MC(GC Dental Industrial Co.,Japan)of heatcured resin.The reline resins used were Lucitone 199(Dentsply international Inc.,USA),Tokuso rebase(Tokuyama Corp.,Japan),and Lightdon-U(Dreve-Dentamid-Gmbh,Germany).The reline resins are representative of heat-cured,self-cured,and light-cured resin respectively.Bond strength was examined by use of a three-point transverse flexural strength test. The results were as follows: 1.The bond strength of Lucitone 199 to Acron MC was the highest. 2.The bond strengths of Lucitone 199 and Tokuso rebase to Hi-polycarbonate resulted in a value of approximately one half that of Lucitone 199 to Acron MC,and there were no significant differences between these and the bond strength of Tokuso rebase to Acron MC(p<0.05). 3.The bond strengths of reline resins to Acetal dental were lower than those of reline resins to Hi-polycarbonate. 4.For all base resins Lightdon-U showed lower bond strength than the other reline resins.

Effects Of Metal Surface Treatments On The Shear Bond Strength Between Ni-Cr Denture Base And Reline Resins / 대한치과보철학회지

The purpose of this study was to evaluate the effects of four metal surface treatments on the shear bond strength of reline resin to Ni-Cr alloy. The denture base metal used in this study was Ni-Cr alloy(Ticonium Premium 100, Ticonium Co., U.S.A.). 120 specimens were divided into five metal surface treatments:sandblasting only, MR.BOND(Tokuyama Corp., Japan), Cesead Opaque Primer(Kuraray Co., Japan), METALPRIMER II(GC Corp., Japan)and Super-Bond C&B(Sun Medical Co., Japan) after sandblasting. They were bonded with one of three reline resins: Mild Rebaron(GC Corp., Japan), Mild Rebaron LC(GC Corp., Japan) and Meta Base M(Sun Medical Co.,Japan).Then they were thermocycled 1,000 times at temperature of 4 celsius degrees and 60 celsius degrees. The shear bond strengths were measured using the universal testing machine(Instron,Model 4301, England)with a cross-head speed of 2 mm/min. The results were as follows: 1.All metal primers and adhesive cement significantly improved the bond strength of reline resin to Ni-Cr alloy compared with sandblasted specimens. 2.In Mild Rebaron and Mild Rebaron LC,Cesead Opaque Primer showed the highest bond strength, but the differences among Cesead Opaque Primer,MR.BOND and METALPRIMER II were not significant.The bond strength of Cesead Opaque Primer was significantly different with that of Super-Bond C&B. 3.In Meta Base M,Super-Bond C&B showed the highest bond strength,but there was no difference between Super-Bond C&B and three metal primers. 4.There was no difference in the bond strength between Mild Rebaron and Mild Rebaron LC when metal surface was treated with the same method. 5.The bond strengths of Mild Rebaron and Mild Rebaron LC treated with Cesead Opaque Primer were higher than that of Meta Base M.The bond strengths of Mild Rebaron treated with MR. BOND and METALPRIMER II was higher than that of Meta Base M.However,there was no difference among three reline resins treated with Super-Bond C&B.