Evaluation of Bond Strength of Silicone and Acrylic Resin Based Resilient Denture Liners Over A Period of Storage in Water

Background: Two potential problems commonly identified with a denture base incorporating a resilient liner are afailure of the bond between the acrylic resin and resilient liner material and a loss of resiliency of the resilient liner material over time. Methods: The current study was performed to assess the bond strength and hardness of acrylic resilient liner in both auto-polymerized and heat-polymerized forms and silicone resilient liner in auto-polymerized form to a processed denture base resin over a period of water storage for 1 day, 1 week and 1 month. The denture liners investigated were acrylic resin-based heat-polymerized (Super-soft), acrylic resin-based autopolymerized (Coe-Soft) and silicone based autopolymerized (GC-reline) resilient liner. The resilient liners were processed according to manufacturer’s instructions. Tensile bond strength was measured in ASI Instron universal testing machine at a crosshead speed of 20 mm/min, and hardness was measured using a Shore-A durometer. Results: Two-way ANOVA and Tukey HSD tests were used to analyze the data (α=0.05). The results indicated that there were significant differences both in the hardness and bond strength values of resilient liner materials. Conclusion: Autopolymerized silicone resilient liner has increased bond strength and hardness values than autopolymerized acrylic liner but the bond strength and hardness values of autopolymerized silicone liner was less than heat cure acrylic resilient liner.

Nonthermal plasma on the shear bond strength of relining resin to thermoplastic denture base resin / 대한치과보철학회지

PURPOSE: This study evaluated the effect of nonthermal plasma treatment on the bond strength of autopolymerizing relining resin to the injection molded thermoplastic denture base resins (TDBRs) with different surface treatments. MATERIALS AND METHODS: Acrylic Resin (Acrytone), Polyester (Estheshot-Bright), Polyamide (Valplast) and Polypropylene (Weldenz) were subjected to various surface treatments: No treatment, Nonthermal plasma, Sandblasting, Sandblasting and nonthermal plasma. Specimens were bonded using an autopolymerizing relining resin. Shear bond strength was tested using universal testing machine with crosshead speed of 1 mm/min. Statistical analysis by two-way analysis of variance with Tukey's test post hoc was used. RESULTS: Acrytone showed significantly higher shear bond strength value among other TDBR group while Weldenz had the lowest. The sandblasting and nonthermal plasma condition had significantly higher shear bond strength value in all of the resin groups (P < .05). CONCLUSION: The use of nonthermal plasma treatment showed limited effect on the shear bond strength between TDBRs and relining resin, and combination of nonthermal plasma and sandblasting improved the shear bond strength between TDBR and reline material.

Effect of light-curing, pressure, oxygen inhibition, and heat on shear bond strength between bis-acryl provisional restoration and bis-acryl repair materials

PURPOSE: This study aimed to discover a way to increase the bond strength between bis-acryl resins, using a comparison of the shear bond strengths attained from bis-acryl resins treated with light curing, pressure, oxygen inhibition, and heat. MATERIALS AND METHODS: Self-cured bis-acryl resin was used as both a base material and as a repair material. Seventy specimens were distributed into seven groups according to treatment methods: pressure - stored in a pressure cooker at 0.2 Mpa; oxygen inhibition- applied an oxygen inhibitor around the repaired material,; heat treatment - performed heat treatment in a dry oven at 60degrees C, 100degrees C, or 140degrees C. The shear bond strength was measured with a universal testing machine, and the shear bond strength (MPa) was calculated from the peak load of failure. A comparison of the bond strength between the repaired specimens was conducted using one-way ANOVA and Tukey multiple comparison tests (alpha=.05). RESULTS: There were no statistically significant differences in the shear bond strength between the control group and the light curing, pressure, and oxygen inhibition groups. However, the heat treatment groups showed statistically higher bond strengths than the groups treated without heat, and the groups treated at a higher temperature resulted in higher bond strengths. Statistically significant differences were seen between groups after different degrees of heat treatment, except in groups heated at 100degrees C and 140degrees C. CONCLUSION: Strong bonding can be achieved between a bis-acryl base and bis-acryl repair material after heat treatment.

Evaluation of linear dimensional accuracy of hard chairside and laboratory heat cure reline resins at different time intervals after processing.

Context: Relining with heat cure denture base resin is time‑consuming and the patient has to remain without dentures within this period. Recently, some autopolymerizing resins marketed as hard chairside reline systems with low exothermic heat allow the dentists to reline prosthesis directly in the mouth. However, the decision to use these materials must be based on physical properties such as dimensional accuracy that directly influences the accuracy of fit of the denture base. Aim: The aim was to compare the linear dimensional changes of two hard chairside reline resins with two laboratory heat cure resins at 3 times intervals after processing. Settings and Design: A stainless steel split mold (International Organization for Standardization 1567) was used for sample fabrication. Five measurements of the reference dimensions (AB and CD) were measured directly from the mold and the samples with a profile projector, and mean difference were calculated. Subjects and Methods: Forty samples were fabricated by incorporating the split mold into first pour of denture flasks and packing each of the chairside reline resins (“Kooliner” and “Ufi Gel Hard”) and laboratory heat cure resins (“Dental Products of India Heat Cure” and “Trevalon”). The mean difference in dimensional change at 3 times intervals (0 h, 4 days and 2 months) were calculated and subjected to statistical analysis. Statistical Analysis Used: One‑way ANOVA, RMANOVA and post hoc Tukey’s tests. Results: All resins showed different levels of significant shrinkage (P < 0.001) after processing (T0) ranging from −0.128 to −0.310 mm. After 4 days (T1), there was significant shrinkage (P < 0.001) ranging from −0.168 to −0.296 mm. After 2 months (T2), there was again significant shrinkage (P < 0.001) ranging from −0.018 to −0.216 mm. Chairside reline resins showed less dimensional shrinkage at each time interval than the laboratory heat cure resins. Conclusions: Hard chairside resins are dimensionally accurate than the laboratory heat cure resins.

Reattachment of a fractured fragment with relined fiber post using indirect technique: a case report

Although fiber-reinforced posts have been widely used, they sometimes fail to obtain sufficient retention because of an extremely large canal space. To address this, several techniques have been introduced including relining of the fiber-reinforced posts. Here, we used a relined glass-fiber post to increase retention and fitness to the root canal in a crown reattachment case. The relining procedure was performed by using an indirect method on the working cast. This case also highlights the esthetic concerns regarding dehydration of the attached crown fragment.

Impact strength of denture base and reline acrylic resins subjected to long-term water immersion

Water may influence the mechanical properties of the acrylic resins. Thus, the effect of water storage on the impact strength (IS) of one denture base (Lucitone 550 - L) and four reline resins (Tokuyama Rebase II - T; UfiGel Hard - U; Kooliner - K; New Truliner - NT) was evaluated. Bars of L were made (60 x 6 x 2 mm) and relined (2 mm) with T, U, K, NT and L. Intact specimens of each material (60 x 6 x 4 mm) were also fabricated for comparative purposes. Specimens were submitted to Charpy impact tests without water storage (control) and after immersion in water for 7, 90 and 180 days. Data (kJ/m²) analyzed by two-way ANOVA and Tukey's test (p=0.05) revealed that after 90 days, U exhibited an increase in the IS (0.93) compared to 7 days (0.58). K (1.48) and L/K (7.21) exhibited a decrease at the 7-day period (1.01 and 3.23, respectively). NT (0.60) showed an increase in the IS after 180 days (1.52), whereas L/NT (7.70) showed a decrease (3.17). Water immersion improved the IS of U and NT, and decreased the IS of K, L/K, and L/NT. Water may affect differently the IS of acrylic resins and, consequently, the resistance to fracture of relined denture bases.

A água pode influenciar as propriedades mecânicas das resinas acrílicas. Assim, o efeito do armazenamento em água na resistência ao impacto (RI) de uma resina para base de prótese (Lucitone 550-L) e quatro materiais reembasadores (Tokuyama Rebase II-T; UfiGel Hard-U; Kooliner-K; New Truliner-NT) foi avaliado. Barras da resina L foram confeccionadas (60 x 6 x 2 mm) e reembasadas (2 mm) com T, U, K, NT e L. Amostras não reembasadas de cada material também foram confeccionadas (60 x 6 x 4 mm) para fins comparativos. As amostras foram submetidas aos testes de impacto tipo Charpy sem armazenamento (controle) e após imersão em água por 7, 90 e 180 dias. Os resultados (kJ/m²) analisados por meio de ANOVA dois fatores e teste de Tukey (p=0,05) revelaram que, após 90 dias, U exibiu aumento na RI (0,93) comparado com 7 dias (0,58). K (1,48) e L/K (7,21) exibiram diminuição no período de 7 dias (1,01 e 3,23, respectivamente). NT (0,60) apresentou aumento na RI após 180 dias (1,52), enquanto L/NT (7,70) apresentou redução (3,17). A imersão em água melhorou a RI de U e NT e diminuiu a RI de K, L/K, e L/NT. A água pode afetar de maneira diversa a RI das resinas acrílicas e, consequentemente, a resistência à fratura das bases de próteses reembasadas.

A study on the shear bond strength between Co-Cr denture base and relining materials / 대한치과보철학회지

PURPOSE: This study evaluated the bonding strength of direct relining resin to Co-Cr denture base material according to surface treatment and immersion time. MATERIALS AND METHODS: In this study, Co-Cr alloy was used in hexagon shape. Each specimen was cut in flat surface, and sandblasted with 110 microm Al2O3 for 1 minute. 54 specimens were divided into 3 groups; group A-control group, group B-applied with surface primer A, group C-applied with surface primer B. Self curing direct resin was used for this study. Each group was subdivided into another 3 groups according to the immersion time. After the wetting storage, shear bond strength of the specimens were measured with universal testing machine. The data were analyzed using two-way analysis of variance and Tukey post hoc method. RESULTS: In experiment of sandblasting specimens, surface roughness of the alloy was the highest after 1 minute sandblasting. In experiment of testing shear bond strength, bonding strength was lowered on group B, C, A. There were significant differences between 3 groups. According to period, Bonding strength was the highest on 0 week storage group, and the weakest on 2 week storage group. But there were no significant differences between 3 periods. According to group and period, bonding strength of all group were lowered according to immersion time but there were no significant differences on group B and group C, but there was significant difference according to immersion time on group A. CONCLUSION: It is useful to sandblast and adopt metal primers when relining Co-Cr metal base dentures in chair-side.

Wettability of denture relining materials under water storage over time

STATEMENT OF PROBLEM: Poor wettability of denture relining materials may lead to retention problems and patient discomfort. PURPOSE: Purpose of this study is to compare and evaluate wettability of nine denture relining materials using contact angle measurements under air and water storage over time. MATERIAL AND METHODS: Nine denture relining materials were investigated in this study. Two heat-curing polymethyl-methacrylate (PMMA) denture base materials: Vertex RS, Lang, one self-curing polyethyl-methacrylate (PEMA) chairside reline resin: Rebase II, six silicone relining materials: Mucopren soft, Mucosoft, Mollosil(R) plus, Sofreliner Touch, GC Reline(TM) Ultrasoft, Silagum automix comfort were used in this experiment. Contact angles were measured using high-resolution drop shape analysis system (DSA 10-MK2, KRUESS, Germany) under three conditions (in air after setting, 1 hour water storage, and 24 hours water storage). Nine materials were classified into three groups according to material composition (Group 1: PMMA, Group 2: PEMA, Group 3: Silicone). Mean values of contact angles were compared using independent samples t-test and one-way ANOVA, followed by a Scheffe's post hoc analysis (alpha= 0.01). RESULTS: Contact angles of materials tested after air and water storage increased in the following order: Group 1 (PMMA), Group 2 (PEMA), Group 3 (Silicone). Heat-cured acrylic denture base resins had more wettability than silicone relining materials. Lang had the highest wettability after 24 hours of water storage. Silicone relining materials had lower wettability due to their hydrophobicity. Wettability of all denture relining materials, except Rebase II and Mollosil(R) plus, increased after 24 hours of water storage. CONCLUSIONS: Conventional heat-cured resin showed the highest wettability, therefore, it can be suggested that heat-cured acrylic resin is material of choice for denture relining materials.

Effect of surface design on bond strength of relining denture resin / 대한치과보철학회지

STATEMENT OF PROBLEM: Removable partial denture and complete denture often require denture base relines to improve the fit against the tissue-bearing mucosa because of gradual changes in edentulous ridge contours and resorption of underlying bone structure. PURPOSE: This study was performed to investigate the effect of surface design on bond strength of relining denture base resins to denture base acrylic resin. MATERIALS AND METHOD: Heat curing resin(Lucitone 199, Dentsply U.S.A. and Vertex, Dentimex, Holland), self curing resin(Tokuso rebase, Tokuyama, Japan), and visible light curing resin(Triad, Dentsply, U.S.A.) were used in this study. The surface designs were classified as butt, bevel and rabbet joint and the bond strengths were measured by Universial Testing Machine(Zwick Z020, Zwick Co., Germany). RESULTS AND CONCLUSION: The obtained results from this study were as follows; 1. The bond strength of Vertex resin was higher than those of Tokuso rebase and Triad. 2. The bond strength of rabbet and bevel joint was higher than that of butt joint. 3. The failure mode of Triad and Tokuso rebase was mainly adhesive, but cohesive failure was shown mainly in vertex.

Physical Properties Of Relining Denture Base Resins With Different Polymerizing Methods / 대한치과보철학회지

This study would like to measure and compare water sorption and solubility of acrylic resins, with 3 different polymerizing methods, and tensile strength between denture base resin and relining resins. For this experiment, 3 different acrylic resins were used; heat polymerizing resin: Vertex (Dentmex, Zeist,Holland), autopolymerizing resin: Tokuso Rebase (Tokuyama Corp, Tokyo, Japan), and light curing resin: Mild Rebaron LC (GC Corp, Tokyo, Japan) The results were as follows; 1. Tokuso Rebase showed the lowest water sorption, followed by Mild Rebaron LC and Vertex. Among resins, there were some signigicant differences (P0.05). About 50% of Rebaron LC showed cohesive fracture. 4. Tensile strength has more decreased after thermocycling than before, but there was no statistical difference (P>0.05).

A case of allergic contact stomatitis due to denture relining materials / 대한피부과학회지

Many sensitizing chemicals and additives are used in manifacturing and mending dentures. Among them, phtolyldiethanolamine, a kind of accelerto for polymerization, is necessary only in self-curing acrylic resins which are available for repairing and relining of denture. Although the sotirce of denture stomatitis is still controversial, a true allergy to denture base materials can be recognized by a patch test. We report a case of allergic contact stomatitis due to dentn e relining materials in a 65-year-old denturecariying edentulous patient. Patch testievi.aled positive reaction to polyldiethanolamine which is considerd to be contained in a cold curing acrylic resin fluid.