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.

Validation of the Brazilian versions of two inventories for measuring oral health-related quality of life of edentulous subjects

'Objectives: To analyse the validity of the Brazilian versions of OHIP-EDENT and GOHAI as assessment tools of edentulous subjects' OHRQoL. Background: Inventories for measuring oral health-related quality of life (OHRQoL) are important in clinical studies regarding oral rehabilitation. However, there is a need for comprehensive validation after translation into different cultural settings. Materials and methods: The sample comprised of 100 complete denture wearers (29 men, 71 women, mean age of 65.2 +/- 9.9 years). The associations between each OHRQoL inventory and other variables served as measurements of construct validity. Data analysis comprised the Spearman correlation test as well as multiple regression using the OHRQoL inventories as dependent variables and the other scales as determinants. Results: Both OHRQoL inventories showed good correlation with denture satisfaction, whereas lower correlation coefficients were found among the inventories and the HAD subscales. Denture satisfaction alone explained 48% and 39% of the variance found for the OHIP-EDENT and GOHAI, respectively, as assessed by multiple regression. A smaller effect was found for OHIP-EDENT. Conclusion: Both OHIP-EDENT and GOHAI showed good construct validity for measurement of OHRQoL of edentulous subjects.

Evaluation of the flexural strength and elastic modulus of resins used for temporary restorations reinforced with particulate glass fibre

Objective: The flexural strength and the elastic modulus of acrylic resins, Dencor, Duralay and Trim Plus II, were evaluated with and without the addition of silanised glass fibre. Materials and methods: To evaluate the flexural strength and elastic modulus, 60 test specimens were fabricated with the addition of 10% ground silanised glass fibres for the experimental group, and 60 without the incorporation of fibres, for the control group, with 20 test specimens being made of each commercial brand of resin (Dencor, Duralay and Trim Plus II) for the control group and experimental group. After the test specimens had been completed, the flexural strength and elastic modulus tests were performed in a universal testing device, using the three-point bending test. For the specimens without fibres the One-Way Analysis of Variance and the complementary Tukey test were used, and for those with fibres it was not normal, so that the non-parametric Mann-Whitney test was applied. Results: For the flexural strength test, there was no statistical difference (p > 0.05) between each commercial brand of resin without fibres [Duralay 84.32(+/- 8.54), Trim plus 85.39(+/- 6.74), Dencor 96.70(+/- 6.52)] and with fibres (Duralay 87.18, Trim plus 88.33, Dencor 98.10). However, for the elastic modulus, there was statistical difference (p > 0.01) between each commercial brand of resin without fibres [Duralay 2380.64 (+/- 168.60), Trim plus 2740.37(+/- 311.74), Dencor 2595.42(+/- 261.22)] and with fibres (Duralay 3750.42, Trim plus 3188.80, Dencor 3400.75). Conclusion: The result showed that the incorporation of fibre did not interfere in the flexural strength values, but it increased the values for the elastic modulus.

A cross-over randomised clinical trial of eccentric occlusion in complete dentures

The objective of this study is to compare the effects of canine guidance (CG) and bilateral balanced occlusion (BBO) on denture satisfaction and kinesiographic parameters of complete denture wearers, by means of a cross-over trial. Fifty edentulous patients received new maxillary and mandibular complete dentures. After the intra-oral adjustments and adaptation period, 44 participants were enrolled in the trial and randomly received a sequence of occlusal schemes: BBO followed by CG, or CG followed by BBO. Outcomes were assessed after 30 days of each occlusal scheme. Participants answered a denture satisfaction questionnaire and a kinesiograph instrument recorded mandibular physiologic movements and pattern of maxillary denture movement during chewing. Wilcoxon test and paired sample t-test were used to compare satisfaction levels and kinesiographic data for each occlusal scheme, respectively (a = 0.05). The results showed no differences between occlusal schemes on participants satisfaction and in any of the kinesiographic parameters studied, except for the vertical intrusion of the maxillary complete denture during chewing, which was lower with CG. It can be concluded that the occlusal scheme did not influence on satisfaction and kinesiographic parameters evaluated, as long as volume and resilience of residual edentulous ridges of the participants were normal. Clinical Trial Registration Identifier: NC.T01420536.

The influence of mandibular implant-retained overdentures in masticatory efficiency

Objective: To evaluate the masticatory efficiency of patients rehabilitated with conventional dentures (CDs) or implant-retained mandibular overdentures. Background: Despite the evident benefits of implants on mastication as assessed by subjective patient-based outcomes, the extent of implant overdenture treatment effect on food comminution is not well established. Materials and methods: A randomised clinical trial was carried out with 29 completely edentulous patients divided into two groups. The first group was rehabilitated with a mandibular overdenture retained by two splinted implants with bar-clip system, while the second group was rehabilitated with a mandibular CD. Both groups also were rehabilitated with maxillary CDs. Masticatory efficiency and patient satisfaction were assessed 3 months after denture insertion. Masticatory efficiency was evaluated through the colorimetric method with the beads as the artificial test-food. Comparisons for masticatory efficiency and patient satisfaction were performed using Student's t-test (alpha = 0.05). Results: No significant statistical difference was found for masticatory efficiency (p = 0.198). Patient overall satisfaction was significantly higher for the mandibular overdenture (p < 0.001). In addition, mandibular overdenture patients were significantly more satisfied with chewing experience (p < 0.05) and retention of the lower denture (p < 0.005). Conclusion: The results of this study suggest that mandibular overdenture significantly improves chewing experience, although limited effect on masticatory efficiency has been observed.

Prosthetic misfit of implant-supported prosthesis obtained by an alternative section method

PURPOSE. Adequate passive-fitting of one-piece cast 3-element implant-supported frameworks is hard to achieve. This short communication aims to present an alternative method for section of one-piece cast frameworks and for casting implant-supported frameworks. MATERIALS AND METHODS. Three-unit implant-supported nickel-chromium (Ni-Cr) frameworks were tested for vertical misfit (n = 6). The frameworks were cast as one-piece (Group A) and later transversally sectioned through a diagonal axis (Group B) and compared to frameworks that were cast diagonally separated (Group C). All separated frameworks were laser welded. Only one side of the frameworks was screwed. RESULTS. The results on the tightened side were significantly lower in Group C (6.43 +/- 3.24 mu m) when compared to Groups A (16.50 +/- 7.55 mu m) and B (16.27 +/- 1.71 mu m) (P<.05). On the opposite side, the diagonal section of the one-piece castings for laser welding showed significant improvement in the levels of misfit of the frameworks (Group A, 58.66 +/- 14.30 mu m; Group B, 39.4.8 +/- 12.03 mu m; Group C, 23.13 +/- 8.24 mu m) (P<.05). CONCLUSION. Casting diagonally sectioned frameworks lowers the misfit levels. Lower misfit levels for the frameworks can be achieved by diagonally sectioning one-piece frameworks. [J Adv Prosthodont 2012;4:89-92]

Trial of Experimental Toothpastes Regarding Quality for Cleaning Dentures

The aim of this study was to evaluate the efficacy of experimental toothpastes for removing denture biofilm by means of a randomized crossover trial. Thirty volunteers brushed their dentures using a brush and four pastes: (1) Corega refreshing mint (control), (2)0.2% chloramine T, (3)1.0% chloramine T, and (4) 0.01% fluorosurfactant. Each paste was used for 7 days, and participants were randomized to use them according to one of four sequences. Biofilm was disclosed (neutral red) after each period, photographed, and quantified by means of a software program. All experimental toothpastes were similar to the control in terms of posttreatment biofilm coverage. Int J Prosthodont 2012;25:157-159.

Antimicrobial Photodynamic Therapy in the Treatment of Oral Candidiasis in HIV-Infected Patients

Objective: Antimicrobial photodynamic therapy (aPDT) has been used to combat local infections, and it consists of the combination of a photosensitizer, a light source, and reactive oxygen species (ROS) to kill microbial cells. In this study, we evaluated the effectiveness of aPDT in the treatment of candidiasis in HIV-infected patients. Methods: Twenty-one patients were divided into three groups. Control group (CG) was treated with the conventional medication for candidiasis (fluconazole 100 mg/day during 14 days). Laser group (LG) was subjected to low-level laser therapy (LLLT), wavelength 660 nm, power of 30 mW, and fluence of 7.5 J/cm(2), in contact with mucosa during 10 sec on the affected point. An aPDT group (aPDTG) was treated with aPDT, that is, combination of a low-power laser and methylene blue 450 mu g/mL. Pre-irradiation time was 1 min. Parameters of irradiation were the same ones as for the LG, and patients were single irradiated. Patients were clinically evaluated and culture analysis was performed before, immediately after, and 7, 15, and 30 days after the treatment. Results: Our results showed that fluconazole was effective; however, it did not prevent the return of the candidiasis in short-term. LLLT per se did not show any reduction on Candida spp. aPDT eradicated 100% of the colonies of this fungus and the patients did not show recurrence of candidiasis up to 30 days after the irradiation. Conclusions: These findings suggest that aPDT is a potential approach to oral candidiasis treatment in HIV-infected patients.

Foreign Body Ingestion During Dental Implant Procedures

Two cases of swallowing of foreign material related to dental implants during dental practice are described. A conservative approach by clinical-radiographic follow-up was performed in both cases; however, one of the patients required colonoscopy under general anesthesia for the removal of the impacted foreign body from the intestinal region. These complications not only have associated economic cost but also carry the risk of malpractice litigation against the professional; thus, the surgeon was responsible for all the costs of hospital and surgery management of this case. Details of the clinical signs, radiographic examinations, type of treatment, and follow-up are presented.

Antimicrobial Properties and Cytotoxicity of an Antimicrobial Monomer for Application in Prosthodontics

Purpose: This study aimed to investigate the antimicrobial properties and cytotoxicity of the monomer methacryloyloxyundecylpyridinium bromide (MUPB), an antiseptic agent capable of copolymerizing with denture base acrylic resins. Materials and Methods: The antimicrobial activity of MUPB was tested against the species Candida albicans, Candida dubliniensis, Candida glabrata, Lactobacillus casei, Staphylococcus aureus, and Streptococcus mutans. The minimum inhibitory and fungicidal/bactericidal concentrations (MIC, MFC/MBC) of MUPB were determined by serial dilutions in comparison with cetylpyridinium chloride (CPC). The cytotoxic effects of MUPB at concentrations ranging from 0.01 to 1 g/L were assessed by MTT test on L929 cells and compared with methyl methacrylate (MMA). The antimicrobial activity of copolymerized MUPB was tested by means of acrylic resin specimens containing three concentrations of the monomer (0, 0.3, 0.6% w/w). Activity was quantified by means of a disc diffusion test and a quantification of adhered planktonic cells. Statistical analysis employed the Mann-Whitney test for MIC and MFC/MBC, and ANOVA for the microbial adherence test (a= 0.05). Results: MUBP presented lower MIC values when compared with CPC, although differences were significant for C. dubliniensis and S. mutans only (p= 0.046 and 0.043, respectively). MFC/MBC values were similar for all species except C. albicans; in that case, MUPB presented significantly higher values (p= 0.046). MUPB presented higher cytotoxicity than MMA for all tested concentrations (p < 0.001) except at 0.01 g/L. Irrespective of the concentration incorporated and species, there was no inhibition halo around the specimens. The incorporation of MUPB influenced the adhesion of C. albicans only (p= 0.003), with lower CFU counts for the 0.6% group. Conclusions: It was concluded that non-polymerized MUPB has an antimicrobial capacity close to that of CPC and high cytotoxicity when compared with MMA. The antimicrobial activity of MUPB after incorporation within a denture base acrylic resin did not depend on its elution, but was shown to be restricted to C. albicans.

Photodynamic inactivation of microorganisms present on complete dentures. A clinical investigation

The aim of this study was to evaluate the effectiveness of photodynamic therapy (PDT) for the disinfection of complete dentures. Biofilm samples were collected from dentures of 60 denture users who were randomly divided into four experimental groups (n = 15 each): subjects whose maxillary dentures were sprayed with 50 and 100 mg/l of PhotogemA (R) suspension (groups P50S and P100S) and patients whose maxillary dentures were treated with 50 and 100 mg/l of PhotogemA (R) gel (groups P50G and P100G). Dentures with photosensitizers were left in the dark for 30 min (pre-irradiation time) and then irradiated with blue LED light at 37.5 J/cm(2) (26 min). Denture samples were taken with sterile cotton swab before (left side surfaces) and after (right side surfaces) PDT. All microbial material was diluted and plated on selective media for Candida spp., Staphylococcus mutans spp., streptococci and a non-selective media. After incubation (48 h/37A degrees C), the number of colony-forming units (cfu/ml) was counted. Microorganisms grown on selective media were identified using biochemical methods before and after PDT. The data were submitted to McNemar and Kruskal-Wallis tests (alpha = 0.05). No growth after PDT was observed in 60, 53, 47, and 40% of dentures from P100G, P50G, P100S, and P50S groups, respectively. When evidence of microorganisms' growth was observed, PDT regimens eliminated over 90% of microorganisms on dentures. This clinical study showed that PDT was effective for disinfecting dentures.

Alternativa protética para correção da angulação com componentes não indexados sobre implantes Cone Morse indexados: sistema tubo parafuso

From a recent perspective the morse-taper dental implants connections are increasingly being used as an alternative for replacement of a missing teeth. Nevertheless, there are a large variety of prosthetic components available on the market with some limitations regarding the final prothesis. This article demonstrated the difficulties and limitations of prosthesis implant-retained connections when using morse-taper implants (with a prosthetic index) case in which the surgical placement of the implant wasn’t successfully performed. The alternative to overcome this scenario was the technique using the tube screw over the top of a mini abutment component. It was possible to manufacture and to have satisfactory adaptation, achieving the satisfaction of the patient, restoring function and esthetics.

Planejamento reverso em próteses totais implanto suportadas com carga imediata

The main objective of this paper was to discuss the importance of the reverse planning as guidance to surgical procedures on immediate loading implant-retained prosthesis, presenting a case report. Such design aims to define anchorage orientation after determination of prosthetic design. This is quite important because the possibility of success of cases with this kind of planning may achieve high levels of satisfaction. Another important aspect is the possibility of fast and definitive restoration of patients’ function and aesthetics

Reestablishment of occlusion through overlay removable partial dentures: a case report

Loss of posterior teeth may cause an imbalance in the stomatognathic system. Overlay removable partial dentures (ORPD) are a reversible and relatively inexpensive treatment for patients with severely worn teeth. This paper presents a treatment with ORPD in a 55-year-old male patient who had severe attrition in the maxillary and mandibular teeth, temporomandibular joint pain and reduced vertical dimension of occlusion (VDO). The treatment consisted in the reestablishment of the VDO using Lucia’s jig, fabricating removable partial denture with reconstruction of the worn teeth without preparation. This therapy can be used as an alternative treatment to provide esthetic, function and stable occlusion in patients with severely worn teeth.