Oral health related quality of life of edentulous patients after denture relining with a silicone-based soft liner

Background: Knowledge of benefits caused by a treatment on quality of life is very relevant. Despite the wide use and acceptance of soft denture liners, it is necessary to evaluate the patient's response about the use of these materials with regard to improvement in oral health related quality of life (OHRQoL). Objectives: The aim of this study was to evaluate the influence of denture relining in the OHRQoL of edentulous patients. Materials and methods: Thirty-two complete denture wearers had their lower dentures relined with a silicone-based material (Mucopren soft, Kettenbach, Germany) according to chairside procedures. OHRQoL was assessed before and after 3 months of relining by means of OHIP-EDENT, and the median scores were compared by Wilcoxon test (p <= 0.05). Results: After 3 months of relining, participants reported significant improvement of their OHRQoL (p <= 0.01). Conclusion: Denture relining with a soft liner may have a positive impact on the perceived oral health of edentulous patients.

Evaluation of experimental cleanser solution of Ricinus communis: effect on soft denture liner properties

Objective: This study evaluated colour stability, hardness and roughness of soft denture liners after immersion in various cleansers. Materials and methods: Thirty specimens (14 mm x 4 mm) of Elite Soft Relining (ES) and Mucopren Soft (MS) were randomly immersed in distilled water at 37 degrees C, sodium hypochlorite 1%, and an experimental Ricinus communis solution (RC) for 7, 15 and 183 continuous days. Results: ANOVA (p < 0.05) and Tukey's test indicated that after T7 (mu =8.79 +/- 7.36); T15 (mu = 4.23 +/- 2.62) and T183 (mu = 8.78 +/- 3.16), MS presented a higher increase in hardness than ES. After T7, MS underwent an increase in roughness (mu = 0.09 +/- 0.80); ES underwent a decrease (mu = -0.08 +/- 0.16). RC caused the smallest variation in roughness. After T15, both materials presented an increase in roughness. After T183, ES (mu = -0.30 +/- 0.48) presented a higher roughness variation than MS (mu = -0.07 +/- 0.32). Hypochlorite caused an increase in roughness (mu = 0.02 +/- 0.19). Conclusion: After all periods ES presented higher colour alteration than MS; highest colour alteration was caused by hypochlorite. Both materials were more stable after immersion in RC.

Peel bond strength of resilient liner modified by the addition of antimicrobial agents to denture base acrylic resin

In order to prolong the clinical longevity of resilient denture relining materials and reduce plaque accumulation, incorporation of antimicrobial agents into these materials has been proposed. However, this addition may affect their properties. Objective: This study evaluated the effect of the addition of antimicrobial agents into one soft liner (Soft Confort, Dencril) on its peel bond strength to one denture base (QC 20, Dentsply). Material and Methods: Acrylic specimens (n=9) were made (75x10x3 mm) and stored in distilled water at 37 degrees C for 48 h. The drug powder concentrations (nystatin 500,000U - G2; nystatin 1,000,000U - G3; miconazole 125 mg - G4; miconazole 250 mg - G5; ketoconazole 100 mg - G6; ketoconazole 200 mg - G7; chlorhexidine diacetate 5% - G8; and 10% chlorhexidine diacetate - G9) were blended with the soft liner powder before the addition of the soft liner liquid. A group (G1) without any drug incorporation was used as control. Specimens (n=9) (75x10x6 mm) were plasticized according to the manufacturers' instructions and stored in distilled water at 37 degrees C for 24 h. Relined specimens were then submitted to a 180-degree peel test at a crosshead speed of 10 mm/min. Data (MPa) were analyzed by analysis of variance (alpha=0.05) and the failure modes were visually classified. Results: No significant difference was found among experimental groups (p=0.148). Cohesive failure located within the resilient material was predominantly observed in all tested groups. Conclusions: Peel bond strength between the denture base and the modified soft liner was not affected by the addition of antimicrobial agents.

Effects of the Compaction Pressure on the Magnetic Properties of a Sintered Fe-Based Alloy

The structural and magnetic properties of a Fe-based alloy before and after sintering have been analyzed. X ray diffraction measurements confirm the deformation of the magnetic particles in the compacted samples. After sintering, hysteresis energy dissipation, remanence and intrinsic coercivity differ by less than 10% as porosity changes from 15 to 7%.

Effect of denture cleansers on metal ion release and surface roughness of denture base materials

Chemical disinfectants are usually associated with mechanical methods to remove stains and reduce biofilm formation. This study evaluated the effect of disinfectants on release of metal ions and surface roughness of commercially pure titanium, metal alloys, and heat-polymerized acrylic resin, simulating 180 immersion trials. Disk-shaped specimens were fabricated with commercially pure titanium (Tritan), nickel-chromium-molybdenum-titanium (Vi-Star), nickel-chromium (Fit Cast-SB Plus), and nickel-chromium-beryllium (Fit Cast-V) alloys. Each cast disk was invested in the flasks, incorporating the metal disk to the heat-polymerized acrylic resin. The specimens (n=5) were immersed in these solutions: sodium hypochlorite 0.05%, Periogard, Cepacol, Corega Tabs, Medical Interporous, and Polident. Deionized water was used as a control. The quantitative analysis of metal ion release was performed using inductively coupled plasma mass spectrometry (ELAN DRC II). A surface analyzer (Surftest SJ-201P) was used to measure the surface roughness (µm). Data were recorded before and after the immersions and evaluated by two-way ANOVA and Tukey's test (α=0.05). The nickel release proved most significant with the Vi-Star and Fit Cast-V alloys after immersion in Medical Interporous. There was a significant difference in surface roughness of the resin (p=0.011) after immersion. Cepacol caused significantly higher resin roughness. The immersion products had no influence on metal roughness (p=0.388). It could be concluded that the tested alloys can be considered safe for removable denture fabrication, but disinfectant solutions as Cepacol and Medical Interporous tablet for daily denture immersion should be used with caution because it caused greater resin surface roughness and greater ion release, respectively.

Extraoral Implants in the Rehabilitation of Craniofacial Defects: Implant and Prosthesis Survival Rates and Peri-Implant Soft Tissue Evaluation

Purpose: Few reports have evaluated cumulative survival rates of extraoral rehabilitation and peri-implant soft tissue reaction at long-term follow-up. The objective of this study was to evaluate implant and prosthesis survival rates and the soft tissue reactions around the extraoral implants used to support craniofacial prostheses. Materials and Methods: A retrospective study was performed of patients who received implants for craniofacial rehabilitation from 2003 to 2010. Two outcome variables were considered: implant and prosthetic success. The following predictor variables were recorded: gender, age, implant placement location, number and size of implants, irradiation status in the treated field, date of prosthesis delivery, soft tissue response, and date of last follow-up. A statistical model was used to estimate survival rates and associated confidence intervals. We randomly selected 1 implant per patient for analysis. Data were analyzed using the Kaplan-Meier method and log-rank test to compare survival curves. Results: A total of 150 titanium implants were placed in 56 patients. The 2-year overall implant survival rates were 94.1% for auricular implants, 90.9% for nasal implants, 100% for orbital implants, and 100% for complex midfacial implants (P = .585). The implant survival rates were 100% for implants placed in irradiated patients and 94.4% for those placed in nonirradiated patients (P = .324). The 2-year overall prosthesis survival rates were 100% for auricular implants, 90.0% for nasal implants, 92.3% for orbital implants, and 100% for complex midfacial implants (P = .363). The evaluation of the peri-implant soft tissue response showed that 15 patients (26.7%) had a grade 0 soft tissue reaction, 30 (53.5%) had grade 1, 6 (10.7%) had grade 2, and 5 (8.9%) had grade 3. Conclusions: From this study, it was concluded that craniofacial rehabilitation with extraoral implants is a safe, reliable, and predictable method to restore the patient's normal appearance. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:1551-1557, 2012

Evaluation of Complete Denture Quality and Masticatory Efficiency in Denture Wearers

Purpose: This study aimed to investigate (1) the influence of complete denture quality and years of denture use on masticatory efficiency and (2) the relationship between complete denture quality and years of use. Materials and Methods: A cross-sectional study was conducted with 93 edentulous patients (mean age: 65.6 years) wearing both mandibular and maxillary dentures. Patients were classified into two categories according to years of denture use: <= 2 years and >= 5 years. Masticatory efficiency was evaluated via the colorimetric method with beads as the artificial test food. A reproducible method for objective evaluation of the technical quality of complete dentures was employed. The association between denture quality and years of denture use was analyzed using chi-square and Fisher exact tests. The results of masticatory efficiency testing were analyzed using two-way analysis of variance (with the Tukey post hoc test) in terms of years of denture use <= 2 years, >= 5 years) and denture quality (poor, average, good). Results: A significant relationship was found between denture quality and years of denture use (P < .05). Masticatory efficiency differed significantly (P < .05) between patients with <= 2 years of denture use (0.101 +/- 0.076 absorbance) and >= 5 years of use (0.068 +/- 0.076 absorbance). Masticatory efficiency was not influenced by denture quality. Conclusions: Complete denture quality and masticatory efficiency significantly decreased over time. However, complete denture quality did not influence masticatory efficiency. Int J Prosthodont 2012;25:625-630.

Evaluation of Vickers hardness of different types of acrylic denture base resins with and without glass fibre reinforcement

Objective: To evaluate the Vickers hardness of different acrylic resins for denture bases with and without the addition of glass fibres. Background: It has been suggested that different polymerisation methods, as well as the addition of glass fibre (FV) might improve the hardness of acrylic. Materials and methods: Five types of acrylic resin were tested: Vipi Wave (VW), microwave polymerisation; Vipi Flash (VF), auto-polymerisation; Lucitone (LT), QC20 (QC) and Vipi Cril (VC), conventional heat-polymerisation, all with or without glass fibre reinforcement (GFR) and distributed into 10 groups (n = 12). Specimens were then submitted to Vickers hardness testing with a 25-g load for 30 s. All data were submitted to ANOVA and Tukey's HSD test. Results: A significant statistical difference was observed with regard to the polymerisation method and the GFR (p < 0.05). Without the GFR, the acrylic resin VC presented the highest hardness values, and VF and LT presented the lowest. In the presence of GFR, VC resin still presented the highest Vickers hardness values, and VF and QC presented the lowest. Conclusions: The acrylic resin VC and VW presented higher hardness values than VF and QC resins. Moreover, GFR increased the Vickers hardness of resins VW, VC and LT.

Effect of Chlorhexidine on Denture Biofilm Accumulation

Purpose: Adequate denture hygiene can prevent and treat infection in edentulous patients, who are frequently elderly and have difficulty brushing their teeth. This study evaluated the efficacy of complete denture biofilm removal using a chlorhexidine solution in two concentrations: 0.12% and 2.0%. Materials and Methods: Sixty complete denture wearers participated in a trial for 21 days after receiving brushing instructions. They were distributed into three groups, according to the tested solution and regimen (n = 20): (G1) Control (daily overnight soaking in water); (G2) daily immersion at home in 0.12% chlorhexidine for 20 minutes after dinner; and (G3) a single immersion in 2.0% chlorhexidine for 5 minutes at the end of the experimental period, performed by a professional. Biofilm coverage area (%) was quantified on the internal surface of maxillary dentures at baseline and after 21 days. Afterward, the differences between initial and posttreatment results were compared by means of the Kruskal-Wallis test (a = 0.05). Results: Median values for biofilm coverage area after treatment were: (G1) 36.0%; (G2) 5.3%; and (G3) 1.4%. Differences were significant (KW = 35.25; p < 0.001), although G2 and G3 presented similar efficacy in terms of biofilm removal. Conclusions: Both chlorhexidine-based treatments had a similar ability to remove denture biofilm. Immersion in 0.12% or 2.0% chlorhexidine solutions can be used as an auxiliary method for cleaning complete dentures.

Abrasiveness of conventional and specific denture-cleansing dentifrices

This study analyzed the weight loss and surface roughness caused in Plexiglass specimens by conventional dentifrices (Sorriso, Colgate and Close Up) and specific dentifrices used for cleaning of dentures (Corega and Dentu Creme). Plexiglass specimens were divided into 6 groups (n=6) including: a control (distilled water - DW) and experimental groups. Brushing was performed in a toothbrushing machine with a soft brush and a dentifrice suspension and DW according to different brushing times (50, 100, 200 and 250 min -18,000, 36,000, 72,000 and 90,000 cycles, respectively, calculated to correspond to 1, 2, 4 and 5 years of regular brushing). The results of weight loss and surface roughness were analyzed by ANOVA and Tukey’s test at 5% significance level. In all tested times, the effect of DW was insignificant. Dentifrices differed significantly from DW in the initial period. Corega dentifrice caused greater mass loss in all studied times, followed by Close Up. Dentifrices resulted in a surface roughness similar to the DW at 50 min. In the other times, Sorriso, Colgate and Corega caused more surface roughness than DW. In conclusion, specific dentifrices caused larger mass loss and lower surface roughness as conventional dentifrice.

CHO cell adhesion on modified surfaces of different materials.

Epithelial cells are mainly responsible for the formation of tissues that cover the external and internal surfaces of organs like skin, lining of the lungs and intestines. The cells must adhere to substrates and to each other in compliance with certain stimulus. In this way, adhesion properties can be regulated by the cell which simultaneously senses the chemical and mechanical properties of its environment. Their adhesion and growth on biomaterials depends on substrate properties such as surface wettability, topography and chemistry. The aim of this study is to investigate cell-surface interactions using several materials and different surfaces.