Resilient Denture Liners Research Articles

The Effect of Various Disinfection Methods on The Tensile Bond Strength of Soft Lining Material

Disinfection of dentures and resilient denture liners were preferred for cross-contamination treatment and better safety. Nevertheless, it has been found that these techniques affect the physical and mechanical properties of denture liners. Objective: To evaluate the impact of various disinfection methods on the tensile bond strength of acrylic soft liner. Material and Methods: 25 samples were made, then divided randomly into five groups (4 disinfection groups as well as a control group), after the daily disinfection procedure, distilled water was used to store the samples at room temperature. After 30 days, a universal testing device (Gester, China) was used to assess the tens ile bond strength. The machine applied force to the specim ens at a crosshead constant speed of 5 mm/minute until failure was recorded. Statistics software (SPSS) was used to analyze the measurements. Results: After 30 days of regular ex posure to different disinfection methods, a greater mean value for bond strength showed in the control group while the lesse r value was in the chlorhexidine group. No significant difference was found between the control and Protefix tablet groups. The sodium hypochlorite and microwave groups had no significant difference between them, but they were significantly different from the control, Protefix tablet, and chlorhexidine groups. the chlorhexidine group was significantly different from the control and other disinfected groups. Conclusion: All disinfected soft liners revealed a decrease i n tensile bond strength, which was not significant with the protefix cleansing tablet but significant with the chlorhexidine, sodium hypochlorite, and microwave regimes.

Enhancing the physical properties of acrylic resilient denture liner using graphene oxide nanosheets

AbstractResilient denture liners (RDLs) change their hardness in a short time. Hence, their usefulness is limited to the short term only. Therefore, this laboratory study investigated the influence of graphene oxide (GO) nanosheets incorporation on the longevity of a commercially available RDL material. An auto‐polymerizing acrylic‐based RDL was selected for this purpose. The control group (G0) was prepared as such according to the manufacturer's instructions. However, for the G1 group, 0.1 wt/wt% of GO nanosheet was incorporated in powder of RDL. Similarly, G2 group and G3 group were the composites of 0.3 and 0.6 wt/wt% of the GO‐resin matrix. A total of 60 disk‐shaped samples were prepared, having three subgroups with 15 disks each (n = 15). Surface roughness, water contact angle, Shore A hardness, water sorption, and solubility parameters were evaluated using a two‐way analysis of variance (p < .05). GO nanosheets facilitated in reducing the hardness of RDL without affecting the surface roughness and wettability properties. Additionally, statistically reduced water solubility and sorption values were observed in G3 group, that is, 0.69 ± 0.25% and 0.93 ± 0.18%, respectively, compared to 1.17 ± 0.13% and 1.41 ± 0.18%, respectively, of the control group at the end of 14‐day water immersion. The incorporation of GO nanosheets seems a viable option for the enhanced physical properties and clinical life of RDLs.

Soft Denture Liner Adhesion to Conventional and CAD/CAM Processed Poly(Methyl Methacrylate) Acrylic Denture Resins-An In-Vitro Study.

This study aimed to evaluate the airborne-particle abrasion surface treatment effects on the tensile bond strength (TBS) between resilient denture liner and CAD/CAM or conventional heat polymerized poly (methyl methacrylate) (PMMA) acrylic denture resins. A total of 48 dumbbell-shaped specimens (70 mm in total length, and 12 mm and 7 mm in diameter at the thickest and thinnest section, respectively) were prepared from CAD/CAM and conventional acrylic resins. Before relining with denture liner, 12 specimens from each material were surface-treated by 110 µm Al2O3 airborne-particle abrasion, and the remaining specimens served as control (no treatment). Following relining, all the specimens were aged by thermal cycling (1000 cycles, 5–55 °C). The TBS of denture liner to acrylic denture resins was tested in a universal testing apparatus at a 5 mm/min crosshead speed. The debonded surfaces were visually examined for the failure modes. ANOVA and multiple comparisons posthoc analysis tests were applied to determine the significant difference in TBS between the study groups (α = 0.05). A significant difference in TBS was observed between the control and surface treated groups (p < 0.001) for both acrylic resins materials. However, there was no statistically significant difference in bond strength between the acrylic resins materials (p = 0.739). Surface treatment with airborne-particle abrasion demonstrated increased TBS of the soft denture liners to acrylic resins. The TBS of conventional and CAD/CAM acrylic resins to soft denture liners were not considerably different.

Comparison of tensile bond strength of denture reline materials on denture bases fabricated with CAD-CAM technology

Statement of problemStudies that have analyzed the bond strength of resilient denture liners to milled denture bases are sparse, and the authors are unaware of research that has investigated the tensile bond strength of denture relining materials to 3D-printed denture bases. PurposeThe purpose of this in vitro study was to evaluate the tensile bond strength of both hard and soft denture reline materials on denture bases fabricated by 3D printing and computer-aided design and computer-aided manufacture (CAD-CAM) milling technology. Material and methodsInjected, milled, and printed denture base specimens were fabricated (n=30) and bonded to 5 different denture reline materials: soft chairside reline (Coe Soft and PermaSoft), hard chairside reline (Tokuyama Rebase ii and Kooliner), and hard laboratory reline (ProBase Cold). Specimens of each reline material were divided into 5 groups (n=10) and were placed in distilled water for 24 hours before tensile testing. Maximum tensile stress values before failure were recorded, and the failure mode was also determined. The type of failure was analyzed by a scanning electron microscope. Statistics were analyzed with 2-way ANOVA and multiple comparison tests (α=.05). ResultsOverall, no statistically significant difference in tensile bond strength was found in the injected, milled, and printed denture groups. However, the printed denture base group demonstrated significantly lower values of tensile bond strength (P<.05) with PermaSoft, Tokuyama Rebase ii, and ProBase Cold groups than other denture base groups (milled and injected). The milled denture bases had the highest mean value of tensile bond strength with 4 of the 5 denture relining materials tested (Coe Soft, PermaSoft, Tokuyama Rebase ii, and Kooliner). No statistically significant difference (P>.05) was found among the injected, milled, and printed denture bases when relined with Kooliner. When comparing the denture reline type, the lowest values were seen with the soft chairside relining materials, and highest values with the hard laboratory reline material. Among the modes of failure, adhesive failures were observed predominantly with the printed denture base materials relined with soft chairside relining materials, while cohesive and mixed modes of failure were found in the milled and injected denture base groups. ConclusionsThe printed denture bases had significantly lower tensile bond strength values than the injection and milled denture bases with the PermaSoft, Tokuyama Rebase ii, and ProBase Cold denture relines, while milled denture bases demonstrated the highest values of tensile bond strength for all chairside relining groups. In addition, the soft chairside relining materials showed the lowest tensile bond strength values regardless of the denture processing method with respect to the denture base type (injected, printed, and milled) compared with the hard relining materials.

A comparative study of patients satisfaction with conventional and relined mandibular complete dentures

Edentulous patients are usually satisfied with the service of a conventional maxillary denture but not the mandibular denture, particularly if the patients present with advanced atrophy of residual ridges, systemic diseases, chronic tissue soreness or maladaptive denture wearing experience. For such patients, the relining of hard heat cured mandibular dentures with long term resilient denture liners may be considered as a non-surgical alternative to pre-prosthetic procedures or implant supported prostheses. Purpose of The Study: The purpose of the study was to compare the satisfaction level of the patients provided with both conventional and relined mandibular dentures. Materials and Methods: The study was conducted on fifteen edentulous patients. Each patient was provided with one maxillary and two mandibular complete dentures i.e. one conventional and another relined with long term silicone-based resilient liner (Molloplast-B). Patients’ general satisfaction with the two mandibular dentures was evaluated using questionnaire. The data so collected was compared and analyzed statistically. Results: The overall analysis of the results obtained from the study suggested that the use of soft liners may promote a more satisfying life for edentulous patients. There was an improvement in patients’ general satisfaction rating, ability to chew &speak, fit and comfort with relined mandibular dentures as compared to conventional acrylic resin mandibular dentures opposed by conventional maxillary dentures and the majority of patients had a preference for the relined mandibular dentures.

Effectiveness of silicone-based resilient denture liners on masticatory function: A randomised controlled trial

ObjectivesThis randomised controlled trial aimed to compare the masticatory function between the silicone-based resilient denture liner and conventional denture among edentulous patients. MethodsThe trial included edentulous patients who were willing to have a new set of complete dentures. Participants were randomly assigned to receive mandibular complete dentures with either a 1) conventional denture base (CD group) or (2) silicone-based resilient denture liner (RD group). Masticatory performance (evaluated with gummy jelly) and the maximum occlusal force were measured at baseline, on final adjustment, and at 3 months after the final adjustment. The outcomes were analyzed using two-way mixed analysis of variance and a paired t-test. The statistical significance was set at p < 0.05. ResultsThe masticatory performance was lower in the RD group than in the CD group; it increased significantly over time in the CD group, but not in the RD group. The maximum occlusal force in the RD group was significantly higher than that in the CD group; it increased significantly over time in the RD group, but not in the CD group. ConclusionsSilicone-based RD liners applied to mandibular complete dentures are effective in improving the maximum occlusal force but not the masticatory performance, as measured with gummy jelly. Clinical significancePrior evidence has suggested that mandibular complete dentures with resilient denture liners improve masticatory function. However, the results of this study indicate that difficulties may remain with the mastication of foods with a certain texture (e.g., gummy jelly).

Satisfaction with resilient denture liner versus acrylic resin telescopic prostheses for patients with ectodermal dysplasia: A nonrandomized crossover clinical trial

Statement of problemPatients with ectodermal dysplasia are characterized by anodontia or oligodontia. How their challenging prosthodontic rehabilitation might be optimized is unclear. PurposeThe purpose of this crossover study was to evaluate the effect of resilient denture liner versus acrylic resin copings in complete overdentures for patients with ectodermal dysplasia. Outcome measures included patient satisfaction, retention, and periodontal health of the abutment tooth. Material and methodsTen partially edentulous participants diagnosed with ectodermal dysplasia were recruited from the Faculty of Dentistry, Cairo University, Egypt, and enrolled in this crossover clinical trial. All participants received acrylic resin coping-retained maxillary complete overdentures (group N, stage 1). The acrylic resin copings were then replaced by a resilient denture liner (group S, stage 2). Patient satisfaction, retention, and periodontal health parameters were evaluated 1 week and 3 months after the completion of each stage. Patient satisfaction was assessed with a validated, reliable questionnaire. The results of the periodontal probing depths were tested with repeated measures ANOVA followed by the Bonferroni correction for pairwise comparisons. Tooth mobility, patient satisfaction, retention, and gingival index were tested by using the Wilcoxon signed ranked test. Ordinal data as the sixth and seventh domains of patient satisfaction were tested by using the McNemar test for paired comparisons (α=.05). ResultsThree months after overdenture delivery, a statistically significant difference was found between the groups regarding retention (P=.025), probing depth (P<.001), and gingival index (P=.011) favoring the acrylic resin coping-retained overdentures. Results of tooth mobility (P=.035), overall attitude (P=.041), ease of eating (P=.023), denture comfort (P=.024), and degree of teasing (P=.038) on wearing the denture showed a statistically significant difference between the groups, favoring the resilient denture liner. ConclusionsIn children with oligodontia and ectodermal dysplasia, the resilient denture liner-retained maxillary complete overdenture enhanced patient satisfaction and tooth mobility of anterior teeth, while minimally jeopardizing the periodontal condition of the abutment teeth.

Effectiveness of silicone-based resilient denture liners on the patient-reported chewing ability: A randomized controlled trial.

This randomized controlled trial (RCT) aimed to elucidate the effectiveness of silicone-based resilient denture liners on perceived chewing ability. The RCT included completely edentulous patients on both the maxilla and mandible, who were willing to fabricate a new set of complete dentures. A random permuted block method (block size: 4) was used to assign groups to receive maxilla conventional complete denture and mandibular with either a conventional complete denture (CD) or complete demure relined with silicone-based resilient denture liner (RD). The patient-reported chewing ability of six foods, soybean curd, fish sausage, soybean sprout, cubic rice cracker, hard rice cracker, and dry squid, on a 100-mm visual analog scale was measured and reported at the final adjustment and three months after the final adjustment. Mann-Whitney U test was used to analyze the differences between the CD and RD (p < 0.05). Edentulous patients wearing mandibular complete denture with RD had a higher patient-reported chewing ability than those wearing a CD, but the fish sausage did not in the RD three months after the final adjustment. It also took three months for the patient-reported masticatory ability to improve for cubic rice crackers, hard rice crackers, and dry squid and to show a difference between the RD and CD groups. Although limited to some food types, mandibular complete dentures relined with silicone-based liners improved patient-reported chewing ability.

Soft Liner with antimicrobial activity

Objective: To develop a material for denture relining and assess the microbiological and mechanical properties. The proposed liner was obtained through the incorporation of nanostructured silver vanadate (AgVO3) at 0, 1, 2.5, 5, and 10% polyethyl methacrylate (PEMA) containing plasticizer. Methods: Antimicrobial efficacy was evaluated by the Kirby Bauer agar method against Enterococcus faecalis, Pseudomonas aeruginosa, Candida albicans and Staphyloccocus aureus (n = 5); and mechanical properties were also assessed through roughness, such as Shore A hardness and tensile test. The results were analyzed by ANOVA and Tukey’s Multiple Comparison test (α = 0.05). Results: The material with AgVO3 at concentrations of 1% and 2.5% showed antimicrobial activity for E. faecalis, and 5% and 10% groups were effective for E. faecalis, P. aeruginosa and C. albicans. In the 5% group, hardness remained unchanged (p &lt; 0.001). None of the tested concentrations significantly changed the roughness and the tensile strength (P &gt; 0.05). Conclusion: Obtaining the material with antimicrobial potential promoted efficacy against E. faecalis, P. aeruginosa and C. albicans, kept the roughness property unchanged, did not change the adhesion property of the material to polymethyl methacrylate, and it maintained the hardness values compatible with resilient denture liners.

Resilient liners may reduce pain and discomfort in the short term in patients who wear complete dentures

Furokawa S, Kimoto S, Furuse N, et al. The effects of silicone-based resilient denture liners on pain: a randomized controlled trial [published online ahead of print February 12, 2020]. J Prosthodont Res. https://doi.org/10.1016/j.jpor.2019.11.006.

The effects of silicone-based resilient denture liners on pain: A randomized controlled trial

PurposeThis randomized controlled trial aimed to study the effects of lining mandibular complete dentures with silicone-based resilient denture liners, especially with respect to sensation. MethodsThe trial included completely edentulous patients who were willing to fabricate new set of complete denture. A random permuted block method (block size: 4) was used to assign participants to one of the following groups: mandibular conventional denture (CD) group or mandibular denture with resilient denture liner (RD) group. The outcomes were evaluated using both, objective measures (current perception threshold (CPT) and pain threshold (PT)) for external stimuli measured using the Neurometer CPT® and subjective measures (physical pain and psychological discomfort measured using the Japanese version of Oral Health Impact Profile for Edentulous patients—OHIP-EDENT-J). The outcomes were measured twice, at immediately after completion of denture adjustments (first measurement), and 3 months after the completion of denture adjustments (second measurement). All outcomes were analyzed using the Student t-test. A p-value of <0.05 was considered statistically significant. ResultsCPT was significantly higher with RD than CD only at second measurement with frequency level of 2000 Hz and 5 Hz. The pain thresholds were significantly higher in the RD group than the CD group. The physical pain and psychological discomfort scores were significantly lower in the RD group than in the CD group. ConclusionThis study concludes that edentulous patients wearing mandibular complete dentures with silicone-based resilient denture liners dull perception mandibular ridge mucosa and felt less pain than those without the liners.

Mechanical and Surface Properties of Resilient Denture Liners Modified with Chitosan Salts.

Chitosan (CS) and its derivatives show antibacterial and antifungal properties and could help treat and prevent denture stomatitis (DS). Mechanical and surface properties of resilient denture liners were evaluated when modified with CS salts. CS-hydrochloride (CS-HCl) and CS-glutamate (CS-G) were added to resilient denture liners Ufi Gel P and Coe-Soft at four different concentrations (0.1%, 0.2%, 0.4%, 1% w/w) from which specimens were produced, as well as a control group of each material with no added CS salt. Ten specimens per group (Ø 35 mm, height 6 mm) were manufactured. They were stored in distilled water at 37 °C for a total of 30 days (d). Shore A hardness (SHA) and surface roughness (Ra) were evaluated after 24 h (T1), 7 d (T2), 14 d (T3) and 30 d (T4). Kruskal–Wallis and U-test (Bonferroni-Holm adjusted) were used for statistical analysis (p ≤ 0.05). Ra increased significantly once CS salts were added. SHA increased significantly for some groups, but all specimens fulfilled requirements set by ISO 10139-2:2016. Modification with CS salts does not influence the mechanical properties of the modified resilient denture liners in a clinically relevant manner. Despite the increased roughness, the concept is suitable for further studies. Especially antimicrobial/antibiofilm studies are needed.

Retention force and allowable range of the angle of an implant-supported overdenture attachment system using healing screws and a silicone resilient denture liner

Statement of problemChanges in the intraoral condition immediately after implant placement and in patients using fixed prosthetic appliances with implant abutments cause problems that require the use of an easily adjustable implant-supported overdenture system. PurposeThe purpose of this in vitro study was to develop a simulated implant-supported overdenture attachment system by using healing screws for the patrix and a silicone resilient denture liner for the matrix and to investigate the initial retention force, time-course changes, and allowable range of the angle between attachments. Material and methodsTests on the retention force and allowable range of the angle were performed. Attachments using tissue-level healing screws (height: 2.0 and 3.0 mm) for the patrix and a silicone resilient denture liner for the matrix were prepared. In the retention force measurement test, the frequency of insertion and removal was set at 3 per day to simulate a 4-month relief period. The joined attachment model was pulled apart, and the maximum traction (N) required to remove it was defined as the retention force. The retention force was measured every 90 times (representing the number of insertions and removals per month). To test the allowable angle range, 2 patrices were used. The angle between the 2 patrices was set at 0, 10, 20, and 30 degrees, and the angular limit for joining with the matrix was measured. The initial retention force of the healing screw attachments was compared with that of a polymeric O-ring by using 1-way layout ANOVA followed by the Bonferroni test (α=.05). To analyze time-course changes in the 2 types of healing screw attachments, the retention force before insertion and removal was compared with that after repeated insertions and removals for each simulated period using 1-way layout ANOVA followed by the Dunnett test (α=.05). ResultsThe initial retention force of the 2.0- and 3.0-mm healing screws was 2.4 ±0.1 and 2.6 ±0.2 N. After repeating insertions and removals to simulate use for 4 months, the retention force of the 2.0- and 3.0-mm healing screws was 1.8 ±0.2 and 2.2 ±0.1 N, respectively, both showing significant differences from the initial retention force (P<.05). The allowable angle range test revealed that insertion and removal of the healing screws was possible up to 30 degrees. ConclusionsUnder the conditions of this in vitro study, repeated insertion and removal attenuated the retention force but was still equivalent to the retention force of the O-ring. The allowable range of the angle between patrices for insertion and removal was up to 30 degrees.

Changes in hardness of addition-polymerizing silicone-resilient denture liners after storage in artificial saliva

Statement of problemThe hardness of silicone resilient denture liners was reported to be more stable than that of acrylic resin resilient denture liners. However, the changes in hardness of these materials in artificial saliva are unclear. PurposeThe purpose of this in vitro study was to evaluate changes in the hardness of addition-polymerizing silicone-resilient denture liners for long-term use after storage in artificial saliva. Material and methodsFour addition-polymerizing silicone resilient denture liners were tested: GC Reline Soft, Elite Soft Relining, Megabase, and Mucopren Soft. All were long-term relining materials of the soft type. Fifteen disk-shaped specimens were prepared for each of the tested materials (40 mm in base diameter, 8 mm in thickness). Their initial hardness was assessed with a Shore A durometer, after which they were stored in artificial saliva at a temperature of 37°C. Hardness was examined after 7, 30, and 90 days. Statistical analysis was performed using parametric ANOVA for dependent and independent variables and Tukey honest significant difference (HSD) post hoc tests (α=.05). ResultsAll resilient denture liners increased in hardness during the experiment. The change was least for Elite Soft Relining, and GC Reline Soft was the hardest material. Initially, Megabase and Mucopren Soft were significantly softer than the other 2 materials, but their hardness increased rapidly after the first 7 days of specimen conditioning, achieving values close to Elite Soft Relining. ConclusionsWithin the limitations of the study, room temperature vulcanizing addition-polymerizing polyvinyl siloxanes of the soft type have different initial hardness, and this changes with storage time in artificial saliva at the temperature of the oral cavity.

Adhesive evaluation of three types of resilient denture liners bonded to heat-polymerized, autopolymerized, or CAD-CAM acrylic resin denture bases

Statement of problemLevels of bond strength between different types of resilient denture liner materials bonded to different denture base acrylic resins, CAD-CAM acrylic resins in particular, have not been well reported. PurposeThe purpose of this in vitro study was to measure the tensile bond strength and durability of various combinations of 3 different resilient denture liners bonded to 3 different poly(methyl methacrylate) denture base materials. Material and methodsThe tensile bond strength of 3 resilient denture liners, namely Ufi Gel SC, Silagum-Comfort, and Vertex Soft, combined with heat-polymerized (Vertex Rapid Simplified), autopolymerized (Vertex Self-Curing), and computer-aided design and computer-aided manufacturing (CAD-CAM) (IvoBase CAD) denture base resins were tested by using a universal testing machine (total N=138). Half of the specimens were thermocycled between 5°C and 55°C for 1500 cycles before testing. After testing, modes of failure and interface surfaces were examined using light microscopy and scanning electron microscopy, respectively. Thermogravimetric analysis was carried out to analyze the differences in content between the 3 different denture base acrylic resins. ResultsThe mean tensile bond strength values ranged from 0.36 ±0.1 MPa to 1.51 ±0.46 MPa. CAD-CAM denture base materials showed the lowest range of bond strength when coupled to resilient denture liners (0.36 to 0.42 MPa). No statistically significant differences (P=.74) were found in bond strength between the thermocycled (0.71 ±0.23 MPa) and non-thermocycled groups (0.74 ±0.21 MPa). Silicone-based resilient denture liners exhibited the highest tensile strength with each type of denture resin. All 3 types of failure modes (adhesive, cohesive, and mixed modes) were observed. ConclusionsSilicone-based resilient denture liners produced the highest tensile bond strength to all denture bases tested. Resilient denture liners bonded to CAD-CAM denture bases produced the weakest tensile bond strengths. Thermocycling did not produce statistically significant differences in tensile bond strength of the resilient denture liners to the denture base resins.

Influence of the mechanical properties of resilient denture liners on the retention of overdenture attachments

Statement of problemInformation is lacking about the selection criteria for silicone resilient denture liners applied as a matrix material for attachments on overdentures. PurposeThe purpose of this in vitro study was to investigate the mechanical properties of silicone resilient denture liners and their influence on the initial retention force of overdenture attachments and the reduction in retention force over time. Material and methodsNine types of silicone resilient denture liner were injected and fixed to the matrix section of an experimental denture base. They were then fitted to an epoxy resin model that simulated the residual ridge with a patrix ball attachment (n=10). The retention force of the denture was measured with a digital force gauge, and the maximum force of traction (N) was regarded as the initial retention force. The retention force reduction (N) after repeated insertion and removal (n=5) was calculated by subtracting the retention force after 3348 cycles (3-year simulated insertion and removal) from the initial retention force. The intaglio of the matrix was observed with a scanning electron microscope (SEM) before and after the 3348 cycles. Four mechanical properties (hardness, strain-in-compression, tensile strength, and arithmetic mean roughness) of the resilient denture liners were measured. One-way ANOVA of the initial retention force of each lining material was performed, followed by the Scheffe test (α=.05). Pearson correlation analysis was used (α=.05) to analyze correlations of the initial retention force with the retention force reduction after insertion and removal and the mechanical properties of each material. Multiple regression analysis with the stepwise method extracted the initial retention force and the retention force reduction as dependent variables, and the resilient denture liner mechanical properties as explanatory variables (α=.05). ResultsThe initial retention force of the resilient denture liners was 1.3 to 5.4 N. Multiple comparisons showed significant differences in some groups (P<.05). The retention force reduction of the resilient denture liners was 0.2 to 1.9 N. Multiple regression analysis with the stepwise method extracted hardness and strain-in-compression as explanatory variables for the initial retention force and the retention force reduction. ConclusionsWithin the limitations of this in vitro study, hardness was found to influence the initial retention force of the overdenture, and strain-in-compression influenced the retention force reduction in the 3-year simulation.

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

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

The influence of patient characteristics on acrylic-based resilient denture liners embedded in maxillary complete dentures

PurposeA major complication associated with the use of resilient denture liners (RDLs) is a change in hardness over time. In vivo studies on the deterioration of RDLs over time are needed. We aimed to investigate the influence of patient characteristics on the hardness of acrylic-based RDLs (ARDLs) embedded in complete maxillary dentures. We hypothesized that 1 month after application of the ARDLs, the hardness would be influenced by age, saliva condition, occlusal force, smoking, drinking, denture wearing during sleeping, denture cleanser usage, and denture type. MethodsThirty complete maxillary denture wearers were recruited after obtaining informed consent. One investigator measured the Shore D hardness of the commercially available ARDLs, Soften (SFT), FD Soft (FDS), and Bio Liner (BIO) using a Vesmeter®. The salivary flow rates and pH values and the occlusal force were measured for all patients before initiation of the study. T-tests and Pearson's correlation coefficients were used for the statistical analyses. A p-value of <0.05 was considered statistically significant. ResultsSmoking, wearing dentures while sleeping, use of denture cleansers, and denture type were associated with an increase in the hardness of the RDLs. The resting saliva pH only influenced the hardness of the SFT ARDLs. ConclusionsSmoking, denture wearing while sleeping, denture cleanser usage, denture type, and resting saliva pH are important predictors of the deterioration of ARDLs over time.

The Effects of Er:YAG, Nd:YAG, and Ho:YAG Laser Surface Treatments to Acrylic Resin Denture Bases on the Tensile Bond Strength of Silicone-Based Resilient Liners.

The present study was to assess the effect of surface treatments of Er:YAG, Nd:YAG, and Ho:YAG lasers on the tensile bond strength of a silicone-based resilient liner to an acrylic denture in an in vitro setting. Experimental dumbbell-shaped specimens (75 mm) were produced by combining two acrylate pieces fabricated from heat-polymerized acrylic resin (36 mm) with 3 mm of Molloplast(®)-B filling between them. The specimens (n=200) were randomly divided in half for thermocycling, and each 100 specimen set was randomized into five groups (n=20) with different surface treatments: control (no surface treatment), sandblasting, Er:YAG laser, Nd:YAG laser, and Ho:YAG laser. A tensile bond strength test was performed. The effect of the laser surface treatments was examined with scanning electron microscopy. Only the Er:YAG laser increased the tensile bond strength compared with the other treatments. The other laser groups showed lower bond strengths. The Ho:YAG laser resulted in considerably reduced tensile bond strength. The scanning electron microscopy images showed that applying laser surface treatments modified the surface of the denture base resin. There was not an overall improvement with the use of the studied laser modalities in the adhesion quality of resilient denture liner to acrylic resin, although Er:YAG laser showed a potential to improve their adhesion. These laser modalities need to be subjected to further studies to determine optimal setup for use in prosthodontics.

A Clinical Study of Improved Nitrile Butadiene Rubber Soft Lining Material and Acrylic Denture Base

ABSTRACT Relining of a complete denture essentially involves the recording of an impression within its support surface so as to correct the deficiency that has arisen as a result of tissues changes. Relining can be done simply, accurately and inexpensively by using lining material. In relining, a new thin layer of lining material is added to the existing denture base. Due to residual ridge resorption and irreversible changes in the tissues supporting, the prosthesis become loose and patient may complaint of frequent pain and ulceration. Relining can be done in such patients by using lining. A soft denture liner which is placed in a denture base that contacts tissues provides comfort. Resilient denture liners because of their viscoelastic properties act as shock absorber and reduce and distribute the stress on the denture bearing tissues. However, there is an increased probability of fungal growth on soft lining materials. Adherence of Candida to solid surface, such as denture resin or lining material has been thought to be the first step in successful colonization, subsequent plaque formation and development of pathogenesis. This study is done to find the adherence of Candida albicans to nitrile butadiene rubber (NBR) soft lining material and safe duration of its clinical usage. How to cite this article Bhandari AJ, Bhandari AJ. A Clinical Study of Improved Nitrile Butadiene Rubber Soft Lining Material and Acrylic Denture Base. Int J Prosthodont Restor Dent 2015;5(4):91-94.