Acrylic Denture Teeth Research Articles

Fracture behavior of pontics of fiber-reinforced composite fixed dental prostheses.

To evaluate the load-bearing capacities and failure mechanisms of FRC FDPs using shell-shaped acrylic denture teeth as pontics with different composite resins as filling materials. Eighty-four inlay-retained FDPs with FRC frameworks were made using shell-shaped posterior artificial teeth as pontics. Different composite resins were used as filling materials to complete the shape of the pontics. Four groups (n=21/group) were formed based on the filling material. Each group was subdivided into three subgroups and tested at 90º and 30°. Each FDP was statically loaded from the pontic until the final fracture. ANOVA revealed statistically significant differences in the load-bearing capacities according to filling material, angle and storage (p<0.01). The fracture propagated from the fiber-rich part of the pontic towards the occlusal surface of the FDP. The filling material influenced the load-bearing capacities of FRC FDPs with shell-shaped denture teeth used as pontics.

Effects of different surface treatments on the bond strength of acrylic denture teeth to polymethylmethacrylate denture base material.

The purpose of this study was to investigate the effects of various surface pretreatments in the ridge lap area of acrylic resin denture teeth on the shear bond strength to heat-polymerized polymethylmethacrylate (PMMA) denture base resin. Tooth debonding of the denture is a major problem for patients with removable prostheses. A total of 84 central incisor denture teeth were used in this study. Seven test groups with 12 specimens for each group were prepared as follows: untreated (control, group C), ground, with a tungsten carbide bur (group H), airborne-particle abrasion (group AA), primed with methyl methacrylate (group M), treated with izobutyl methacrylate (group iBMA), Eclipse Bonding Agent applied (group E), and Er:YAG laser irradiated (group L). Test specimens were produced according to the manufacturers' instructions and mounted to a universal testing machine for shear testing with a crosshead speed of 1 mm/min. Data were evaluated by one way variance analysis (ANOVA) and Tukey's test (α=0.05). Similar bond strength values were found between groups L and M, and these were the highest shear bond strengths among the groups. The lowest one was observed in group E. All surface treatments, except group E, exhibited significant difference when compared with group C (p<0.05). Lasing of the ridge lap area to enhance the bond strength of acrylic resin denture teeth to PMMA denture base resin might be an alternative to wetting with MMA monomer. To overcome tooth debonding, surface treatment of the ridge lap area should be performed as part of denture fabrication.

Color stability of denture teeth and acrylic base resin subjected daily to various consumer cleansers.

This study evaluated color stability of acrylic denture teeth and base resins after 48 weeks of commercial denture cleanser simulation. Two brands of denture teeth (Trubyte Portrait IPN, TP; SR Vivodent DCL, SR) in shades A1, B1, and C1 and three acrylic base resins (Lucitone, LU; Paragon, PA; Valplast, VA) prepared to manufacturer's specifications were exposed 10 hours daily to four cleansers (Clorox Bleach, CB; Polident 3 minute, PO3; Efferdent, EF; and Kleenite, KL) and distilled water control, approximating consumer overnight use. Color measurements used the standard Commision International de l'Eclairage (International Commission on Illumination, CIE L*a*b*) color space (0, 4, 12, 24, 36, and 48 weeks.) Color differences (ΔE*) at 48 weeks were subjected to four-way analysis of variance (ANOVA). Mean values were compared with Fisher's (protected least significant difference) intervals (0.05 significance level). Mean color differences (ΔE*) demonstrated color changes in each material. ANOVA-indicated color changes in teeth were significantly affected by both cleansers and teeth brand (p < 0.05), but not shade. Color changes in base resins were significantly affected by cleansers (p < 0.05), but not brand alone. Overall, KL produced the least color change while CB and PO3 produced the most for all materials. After 48 weeks of daily simulation, TP teeth were more color stable than SR in all cleansers except EF (p < 0.0001). Base resin VA was less color stable than LU and PA. Cleanser KL resulted in the lowest color changes. All tested materials yield clinically acceptable color changes (ΔE* < 3.5); all cleansing methods tested can be recommended, although Kleenite demonstrated the least change after 48 weeks.

Achieving a good bond in acrylic resin denture teeth

Achieving a good bond in acrylic resin denture teeth

Monomer priming of denture teeth and its effects on the bond strength of composite resin

The bond strength of acrylic resin denture teeth used as pontics in fiber-reinforced composite fixed dental prostheses needs to be improved. The purpose of this study was to assess the influence of various chemical surface-conditioning monomers on the ridge-lap surface of acrylic resin denture teeth by determining the strength of their bonding to a composite resin and changes in surface hardness. Acrylic resin denture teeth of 2 different brands (Artic 8 and Vitapan Cuspiform) (n=120) were tested. Four monomer systems were used as surface primers (conditioning): a flowable composite resin, methylmethacrylate 99%, composite primer, and a photopolymerizable dimethacrylate resin. Five surface-conditioning exposure times were used: no conditioning, 1, 5, 15, and 60 minutes. Surface microhardness measurements were made after the application of the monomer systems. Shear bond strength tests were subsequently performed, followed by a new surface microhardness indentation after the application of the load. The evaluation of the changes on specimen surfaces was performed with a scanning electron microscope. The differences between the shear bond strength and the surface hardness were evaluated for statistical significance by using a 3-way ANOVA. Tooth brand, monomer used, exposure time, and their 2- and 3-way interactions had a significant effect on the shear bond strength and hardness before and after testing, except for the 3-way interaction effect on hardness before testing. The chemical pretreatment of the ridge-lap surface of acrylic resin denture teeth increased the shear bond strength and influenced the surface hardness. The monomer systems caused dissolution on the denture surfaces.

The bond between acrylic resin denture teeth and the denture base: recommendations for best practice

Failure of the bond between denture teeth and base acrylic resin has been shown to be a cause of denture failure leading to inconvenience and costly repair. The optimal combination of acrylic resin denture tooth, denture base material, laboratory protocol and processing method has not yet been established. Extensive research enables the following recommendations for best practice to be made. Adopt practices that maximise the strength of the bond: select appropriate denture teeth; select base acrylic resin from the same manufacturer as the denture teeth; remove the glaze from ridgelaps of the denture teeth; apply monomer to the ridgelaps of the denture teeth before packing the base acrylic resin dough; use the manufacturers' recommended liquid/powder ratio; follow the manufacturers' recommended curing cycle; allow the flask to cool slowly and rest before deflasking. Adopt practices that avoid factors detrimental to bond strength: remove all traces of wax from the ridge laps of the denture teeth; remove all traces of mould seal from the ridgelaps of the denture teeth. It is evident that a number of factors are involved which may assist or prevent formation of an adequate bond, suggesting that attention to detail by the dental technician may be the most critical factor.

EFFECT OF DENTURE CLEANSERS ON THE COLOR STABILITY OF DIFFERENT DENTURE TEETH MATERIALS

Objectives: Denture cleansers are commonlyused for cleaning partial and complete dentures.The purpose of this in vitro study was to evaluatethe effect of denture cleansers on color stability ofconventional acrylic, reinforced acrylic andporcelain denture teeth materials.Materials and Methods: Maxillary centralincisors in A2 color were used from three types ofdenture teeth (n=10). Denture teeth kept in distilledwater were considered as control group. Testspecimens were immersed in denture cleansers,which prepared according to the manufacturersinstructions. Color measurements were performedbefore immersion of cleansers, after 1 week andafter 3 weeks with a colorimeter. Color changes(ΔE) of the specimens were calculated and theresults were compared statistically with three wayANOVA.Results: Significant differences were found onthe color changes of denture teeth after 1 week and3 weeks of the immersion of denture cleansers(p<0,05). Also ΔE values were increasedsignificantly with time (p<0,05). The lowest ΔEvalues were observed in distilled water. The lowestΔE values were observed in porcelain teeth in alldenture cleansers (p<0,05). Color changes ofconventional acrylic and reinforced acrylic teeth inall denture cleansers after 3 weeks were acceptable.Conclusions: The greatest color change wasobserved in conventional acrylic resin teeth,reinforced acrylic and porcelain teeth, respectively,after immersion of denture cleansers.

Effect of Different Chemical Disinfectants on Color Stability of Acrylic Denture Teeth

The purpose of this study was to evaluate the effects of chemical disinfectants on the color stability of acrylic denture teeth (ADT) via spectrophotometric analysis. A total of 120 central ADT specimens were randomly assigned to eight experimental groups and immersed in the following solutions (n = 15). Tap water/control group (CON), neutral soap (NTS), 2% sodium hypochlorite (SHC1), 5.25% sodium hypochlorite (SHC2), sodium perborate (SPB), povidone-iodine (PVI), chlorhexidine gluconate (CHG), and glutaraldehyde (GTA). Color measurements of teeth were performed by spectrophotometry after 10, 30, 48, 72, 144, and 960 immersion cycles in each tested solution. Color differences (ΔE*) were then evaluated using the Commission Internationale D'Eclairage (CIE) L*a* b* color system. Furthermore, Kruskal-Wallis, Mann-Whitney U, and Friedman comparison tests (α = 0.05) were performed on all data. There were significant differences in ΔE* values (p < 0.05) among the eight experimental groups. In addition, the highest ∆E* values were obtained in group SHC2, followed, respectively, by the SHC1, CHG, SPB, PVI, NTS, and CON groups. All the chemical disinfectants used in the study affected the color values of ADTs. Furthermore, ΔE* values increased along with the number of immersion cycles and total immersion time.

Golden Rectangle Ratio – How Precious Is It? : A Clinical Study

Maxillary central incisors are of critical value in the dental esthetics. The golden rectangle ratio concept may play a role in selecting the optimum width and length of this tooth. The aim of this study is to investigate the existence of this ratio among individuals with natural dentition and routinely used acrylic denture teeth sets and to validate its role in dental esthetics. The clinical crown length of maxillary left and right central incisor (CI) is measured, mean is calculated and combined crown width of left and right central incisors is measured. Crown width to crown length ratio of natural dentition and acrylic denture teeth sets of different manufacturers was calculated and compared with the Golden Rectangle ratio and statistically analysed. Golden rectangle was found to have a significant relationship with esthetic appearance of maxillary central incisors. The results of this study will help in proper selection of teeth for all restorative procedures.

Mandibular implant-supported fixed dental prosthesis with a modified design: A clinical report

This clinical report describes the rehabilitation of a patient with a mandibular implant-supported fixed dental prosthesis. Because of the limited restorative space available in the posterior mandible and in considering the higher wear rate of acrylicresin in comparison with titanium when it opposes metal ceramic restorations, the treatment used a milled titanium barwithacrylic resin denture teeth, which replaced the anterior teeth with milled titanium for the posterior occluding surfaces.

An in vitro study of the effect of different restorative materials on the reliability of a veneering porcelain

Implant-supported, porcelain veneered restorations experience a greater rate of porcelain fracture than tooth-supported restorations. For completely edentulous patients, one approach to minimizing porcelain fracture is touse acrylic resin in the mandible, although its efficacy is unknown. The purpose of this study was to evaluate the reliability of a veneering porcelain fatigued with different restorative materials invitro. Fifty-nine veneering porcelain disk specimens were fabricated by layering veneering porcelain on nickel-chromium base metal alloy disks. Four groups of different indenter materials fatigued the porcelain specimens: group WC, tungsten carbide served as a control; group FC, pressed leucite glass ceramic; group NHC, nanohybrid composite resin denture tooth; and group AR, unfilled acrylic resin denture tooth. Porcelain specimens were randomly divided into 4 groups (n=14). A step-stress accelerated life-testing model was used. Use-level probability Weibull plots were generated, and the reliability of each group was estimated for a theoretical completion of 50 000 cycles at 150 N. Nanohybrid composite resin and unfilled acrylic resin denture tooth groups had higher reliability than tungsten carbide and leucite glass ceramic groups. No significant differences existed between the reliability of the tungsten carbide and leucite glass ceramic groups and the nanohybrid composite resin and acrylic resin denture tooth groups. Veneering porcelain disk specimens fatigued with the unfilled acrylic resin and nanohybrid composite resin denture tooth indenters exhibited higher reliability than the specimens fatigued with either the tungsten carbide or leucite glass ceramic indenters. All of the veneering porcelain disk specimens failed with the same mode of fracture, although thesurface posttest exhibited different fracture characteristics among specimens fatigued with the 4 different materials.

Color degradation of acrylic resin denture teeth as a function of liquid diet: ultraviolet-visible reflection analysis

The effect of different beverages on acrylic resin denture teeth color degradation is evaluated. Ten acrylic resin denture teeth brands were evaluated: Art Plus (AP), Biolux (BX), Biotone IPN (BI), Magister (MG), Mondial 6 (MD), Premium 6 (PR), SR Vivodent PE (SR), Trilux (TR), Trubyte Biotone (TB), and Vipi Dent Plus (VP). Teeth were immersed in staining solutions (coffee, cola, and orange juice) or artificial saliva (control) (n=6) for 1, 7, 15, or 30 days. Specimen colors were evaluated spectrophotometrically based on the Commission Internationale d'Eclairage L*a*b* system. Color differences (ΔE) were calculated between the baseline and post-staining results. Data were evaluated by analysis of variance and Tukey test (α = 0.05). BI (1.82 ± 0.95) and TR (1.78 ± 0.72) teeth exhibited the greatest ΔE values, while BX (0.88 ± 0.43) and MD (1.09 ± 0.44) teeth were the lowest, regardless of solution and measurement period, and were different from BI and TR teeth (P < 0.05). Cola and coffee promoted higher denture teeth color alterations than orange juice and saliva (P < 0.05). Saliva generated the lowest denture teeth color alterations. Greater immersion times caused higher denture teeth color changes. The lifespan of removable dentures and the aesthetic satisfaction of several edentulous patients may be increased with the use of stain-resistant artificial denture teeth.

A technique to restore worn denture teeth on a partial removable dental prosthesis by using ceramic onlays with CAD/CAM technology

High wear resistance of denture teeth on a removable prosthesis contributes substantially to the clinical longevity of the prosthesis. In the restoration of worn denture teeth on a partial removable dental prosthesis (PRDP), acrylic resin denture teeth replacement can be considered if the opposing occlusal surfaces are acrylic, which shows similar wear rates. However, when the antagonistic materials are enamel or ceramic, an alternative material with better wear resistance is recommended for the maintenance of vertical dimension of occlusion over time.

Shear Bond Strength of Denture Teeth to Two Chemically Different Denture Base Resins after Various Surface Treatments

Debonding of acrylic teeth from the denture base remains a major problem in prosthodontics. The objective of this study was to evaluate the effect of various surface treatments on the shear bond strength of the two chemically different denture base resins-polymethyl methacrylate (PMMA) and urethane dimethacrylate (UDMA). Two denture base resins, heat-cured PMMA (Meliodent) and light-activated UDMA (Eclipse), were used in this study. A total of 60 molar acrylic denture teeth were randomly separated into four groups (n = 15), according to surface treatment: acrylic untreated (group AC), Eclipse untreated (group EC), treated with eclipse bonding agent (group EB), and Er:YAG laser-irradiated eclipse (group EL). Shear bond strength test specimens were prepared according to the manufacturers' instructions. Specimens were subjected to shear bond strength test by a universal testing machine with a 1 mm/min crosshead speed. The data were analyzed with one-way ANOVA and post hoc Tukey-Kramer multiple comparison tests (α = 0.05). The highest mean bond strength was observed in specimens of group EB, and the lowest was observed in group EC specimens. A statistically significant difference in shear bond strength was found among all groups (p < 0.001), except between groups EC and EL (p = 0.61). The two chemically different denture base polymers showed different shear bond strength values to acrylic denture teeth. Laser-irradiation of the adhesive surface was found to be ineffective on improving bond strength of acrylic denture teeth to denture base resin. Eclipse bonding agent should be used as a part of denture fabrication with the Eclipse Resin System.

Effect of immersion cleansers on the bond strength between a denture base resin and acrylic resin teeth

The aim of the present study was to assess the shear bond strength between a heat-polymerized denture base resin and acrylic resin teeth after immersion in different denture cleansers by simulating a 180-day use. Two acrylic teeth (Biotone, Biotone IPN, Dentsply Ind. e Com., Rio de Janeiro, RJ, Brazil) were chosen for bonding to a heat-polymerized denture base resin (Lucitone 550- Dentsply Ind. e Com., Rio de Janeiro, RJ, Brazil). Eighty specimens were produced and divided into eight groups (n=10) according to their experimental condition (distilled water, 2% chlorhexidine digluconate, 1% sodium hypochlorite and Corega Tabs). Shear bond strength tests (MPa) were performed with a universal testing machine at a crosshead speed of 0.5mm/min. Data were analyzed by two-way analysis of variance (ANOVA) and Student-Newman–Keuls' multiple comparisons post hoc analysis (α=.05). The shear bond strength results revealed statistically significant differences between the groups. For the Biotone IPN tooth, significantly lower shear bond strength values were found for the group immersed in sodium-perborate solution (4.48±2.18MPa) than for the group immersed in distilled water (control group) (10.83±1.84MPa). For Biotone, significantly higher bond strength values (10.04±3.28MPa) were found for the group immersed in Corega Tabs than for the control group (5.45±2.93MPa). The immersion in denture cleanser solutions was more detrimental to the conventional acrylic denture tooth (Biotone) than to the highly cross-linked denture tooth (Biotone IPN). However, this effect was not observed for the groups immersed in Corega Tabs solution, regardless of the type of denture tooth.

Effect of Chemical and Microwave Disinfection on the Surface Microhardness of Acrylic Resin Denture Teeth

The purpose of this study was to evaluate the effect of simulated disinfections (2% glutaraldehyde, 1% sodium hypochlorite, and microwave energy) on the surface hardness of Trilux, Biocler, Biotone, New Ace, and Magister commercial artificial teeth. Specimens (n = 10) were made with the teeth included individually in circular blocks of acrylic resin, leaving the labial surface exposed. Cycles of simulated chemical disinfection were accomplished with the specimens immersed in the solutions at room temperature for 10 minutes, followed by tap water washing for 30 seconds and storage in distilled water at room temperature for 7 days until the next disinfection. Simulated disinfection by microwave energy was carried out in a domestic oven with 1300 W at a potency of 50% for 3 minutes with the specimens individually immersed in 150 ml of distilled water. Control (no disinfection) and the experimental groups (first and third disinfection cycles) were submitted to Knoop hardness measurements with indentations at the center of the labial tooth surface. Data were submitted to repeated measure two-way ANOVA and Tukey's test (α = 0.05). Biocler, Magister, and Trilux showed lower surface microhardness when submitted to microwave. Lower microhardness for Biotone was promoted by hypochlorite, while no significant difference was shown for New Ace. The third disinfection cycle significantly decreased the tooth surface hardness only for microwave. Different disinfection methods promoted different effects on the microhardness of different types of artificial teeth. Surface microhardness of the teeth was less affected by the simulated chemical disinfections when compared to microwaved specimens.

Penetration of monomer systems into acrylic denture teeth used as pontics

This journal suppl. entitled: Abstracts of the Academy of Dental Materials Annual Meeting, 9-12 October 2013 - Vancouver, BC, Canada

Effect of Plasma Treatment of Acrylic Denture Teeth and Thermocycling on the Bonding Strength to Heat Cured Acrylic Denture Base Material

Effect of Plasma Treatment of Acrylic Denture Teeth and Thermocycling on the Bonding Strength to Heat Cured Acrylic Denture Base Material

Evaluation of shear bond strength of three different types of artificial teeth to heat cure denture base resin: An in vitro study

Bonding of artificial teeth and denture base material remained a significant problem for successful prosthetic treatment. The purpose of this in vitro study was to evaluate shear bond strength of three different artificial teeth with heat cure denture base material after various surface conditioning methods and thermocycling. Ninety mandibular first molar denture teeth were selected. They were divided into three groups, Group I: Nanocomposite resin (Veracia), Group II: Composite teeth (Endura), and Group III: Cross-linked acrylic denture teeth (Acry rock). All groups were further subdivided into subgroups based on surface conditioning methods. Subgroup A: No surface conditioning (control group), Subgroup B: Surface conditioning with methyl methacrylate-based bonding agent (Vitacoll), and Subgroup C: Air abrasion with 50 μm aluminum oxide powder particles plus silane-coupling agent (Monobond-S) and Vitacoll bonding agent. Evaluation of shear bond strength of all the specimens was done using universal testing machine. Mean shear bond strength of Group I, Subgroup B (6.87 ± 0.934) showed higher value when compared with Group II, Subgroup B (6.76 ± 1.84) and Group III, Subgroup B (5.66 ± 2.18). The control group (untreated surface) of all three types of artificial teeth used in this study showed significantly lower shear bond strength values than experimental groups (surface conditioning methods; P < 0.05). The results of this study suggest that there were significant differences in shear bond strength among control group and surface treatment groups of denture teeth bonded to heat cure denture base resin.

Effect of plasma treatment of acrylic denture teeth and thermocycling on the bonding strength to heat cured acrylic denture base material

Acrylic resin polymer s used in prosthodontic treatment as a denture base material for several decades. Separation and debonding of artificial teeth from denture bases present a laboratory and clinical problem affect patient and dentist. The aim of this study is to evaluate the effect of oxygen plasma and argon plasma treatment of acrylic teeth and thermocycling on bonding strength to hot cured acrylic resin denture base material. Materials and Methods: Sixty denture teeth (right maxillary central incisor) are selected. The denture teeth are waxed onto the beveled surface of rectangular wax block according to Japanese standard for artificial teeth. The control group consisted of 20 denture teeth specimen without any treatment. The oxygen plasma group consisted of 20 denture teeth specimen treated with oxygen plasma for two minutes exposure time at plasma apparatus. The argon plasma group consisted of 20 denture teeth treated with argon plasma for two minuets exposure time. All the specimens are undergone flasking and wax elimination procedure in the conventional way. All specimens stored in distilled water for 7 days at 37°C, then half of the specimens of all groups undergoes thermocycling between 5°C - 55°C in 60 seconds cycles for three days and tested for shear bond strength using universal testing machine the data was collected and analyzed statistically using analysis of variance and independent sample t-test. Results: The plasma treated groups showed the higher mean force required to fracture the acrylic teeth from their heat cured acrylic resin denture bases, as compared to control group, and the oxygen plasma treatment group showed higher shear bond value than the argon plasma treatment. The thermocycling had a deleterious effect on bonding strength for control group while the plasma treated group showed an increase in bond strength following thermocycling. Conclusion: Plasma treatment method was an effective approach for increasing the shear bond strength as a result of surface oxidation and chemical etching effect of oxygen plasma and micromechanical interlocking effect of argon plasma.