The effect of denture adhesives on Candida albicans growth in vitro

doi: 10.1111/j.1741‐2358.2011.00478.x
The effect of denture adhesives on Candida albicans growth in vitro Objective: Denture‐wearing favours the growth of Candida. In view of the fact that many denture wearers regularly use adhesives to enhance denture retention, stability and function, the aim of this work was to study the effect of denture adhesives on Candida albicans growth in vitro. Materials and methods: The denture adhesives tested were Corega^® cream, Kukident^® cream, Novafix^® cream, Polident^® cream, Protefix^® cream, Steradent^® cream, Aderyn^® powder, Corega^® ultra powder, Protefix^® powder and Corega^® strip. C. albicans growth curves were obtained in the presence or absence of a 1% solution of the denture adhesive diluted in Sabouraud broth. Macro‐ and microscopic morphological changes in C. albicans were analysed, as was microbial contamination of the denture adhesive. Results: Most of the denture adhesives studied induced morphological changes in C. albicans cells and colonies, but only two had any significant inhibitory effect on yeast growth. Kukident^® cream markedly inhibited C. albicans growth in a concentration‐dependent way, reducing the growth rate by 95%, whereas Corega^® cream also inhibited C. albicans growth but in a non‐concentration‐dependent way, reducing the growth rate by 37%. In addition, denture adhesives available as powders had detectable microbial contamination. Conclusion: Some commercially available denture adhesives showed microbial contamination and some had significant inhibitory effect on C. albicans growth.     

Effect of a denture cleanser on the concentration of volatile sulphur compounds and denture biofilm in institutionalised elderly

doi:10.1111/j.1741‐2358.2009.00341.x
Effect of a denture cleanser on the concentration of volatile sulphur compounds and denture biofilm in institutionalised elderly Objective: To determine the effectiveness of a denture cleanser in reducing the concentration of volatile sulphur compounds (VSC) and its antimicrobial action. Background: Micro‐organisms from the denture biofilm can cause local and systemic disease and halitosis. Denture cleansers are important adjuncts in oral care, but there is limited investigation on their effect in malodour compounds. Material and methods: Nineteen institutionalised elderly who wore at least an upper denture were selected; their VSC concentrations were measured and the denture biofilm was collected. In phase 1, the subjects wore their old denture and data were collected before (B₀) and after 7(A₁), 14(A₂), 28(A₃) days of continuous daily use of the denture cleanser. In phase 2, new dentures were inserted and measurements were made at 30(A_1.1), 60(A_2.2), 90(A_3.3) days of treatment. Results: The VSC concentration increased from B₀ to A₁ (p < 0.05)_, but no differences were found for the others intervals of times. Total micro‐organism data did not show a statistical difference between times in Phase I, but in Phase II, there was a statistical difference (p < 0.05) and a progressive re‐colonisation was observed. Conclusion: Within the limits of this study, it was concluded that the denture cleanser had no antimicrobial effect and VSC levels were not reduced.     

Examination of denture-cleaning methods based on the quantity of microorganisms adhering to a denture

doi: 10.1111/j.1741‐2358.2011.00461.x Examination of denture‐cleaning methods based on the quantity of microorganisms adhering to a denture Objectives: To investigate effective denture‐cleaning methods, we examined the relationships between the quantity of microorganisms adhering to dentures and the use of a denture brush and the frequency of use of a denture cleanser. Subjects and Methods: Denture plaque was collected from the mucosal surface of the examined dentures, which were 142 and 80 upper and lower complete dentures, respectively, worn by 96 outpatients (mean age: 71.9 years) of a university hospital and 41 nursing home residents (mean age: 84.8 years). The collected microorganisms were counted in terms of isolated representative colonies that were cultured and identified using standard methods. The use of a denture brush, the frequency of use, and the type and soaking time of denture cleansers as denture‐cleaning methods were surveyed. Results: The quantity of microorganisms was significantly lower in dentures of denture brush users than in those of non‐users in the outpatients (p < 0.01, Mann–Whitney U test). The quantity of microorganisms was significantly lower in the dentures of outpatients who used a denture cleanser daily or 3–4 times a week than in those who used one once or less per month and in the dentures of nursing home residents who used one daily than in those who used one at other frequencies (p < 0.05, Kruskal–Wallis test, followed by Dunn’s Multiple Comparison test). Conclusion: Within the limitations of this study, it was concluded that the use of a denture brush and daily use of denture cleanser should be recommended to complete dentures wearers as denture‐cleaning methods that effectively reduce the quantity of microorganisms adhering to dentures.     

Factors affecting the distribution and prevalence of oral mucosal lesions in complete denture wearers

Gerodontology 2010; doi: 10.1111/j.1741‐2358.2009.00351.x
Factors affecting the distribution and prevalence of oral mucosal lesions in complete denture wearers Objective: To determine the frequency of the oral lesions related to gender, age, the length of time of denture usage, education level and economic status. Methods: The 153 patients with old complete dentures (CD) were asked to participate in the investigation. The subjects (76 male and 77 female) were 37–85 years of age with a mean age of 61.8 ± 9.8 years. Education, economic status and age factors were estimated in subgroups. The data obtained were evaluated by one‐way anova , Mann–Whitney U‐test, Kruskal–Wallis test, Student’s t‐test and chi‐squared test. The level of statistical significance was set at p < 0.05. Results: The patients who had denture stomatitis and traumatic ulcers were statistically significantly older than the ones who did not have these lesions (p < 0.05). Based on the length of denture usage, patients who had a flabby ridge, fibrous inflammatory hyperplasia, traumatic ulcers (p < 0.01) and denture stomatitis (p < 0.05) were using their dentures statistically significantly longer than the ones who had healthy tissues. Conclusions: The CD wearers should be advised to visit their dentist regularly to prevent oral mucosal lesions due to the changing supporting tissues during the length of denture usage and to improve their quality of life.     

Clinical evaluation of three denture cushion adhesives by complete denture wearers

doi: 10.1111/j.1741‐2358.2010.436.x Clinical evaluation of three denture cushion adhesives by complete denture wearers Objective: The aim of this study was the clinical evaluation of three denture cushion adhesives and whether the results were correlated to Kapur Index for denture‐supporting tissues. Background: Various types of denture adhesives are used among denture patients. However, information on the clinical behaviour of denture cushions is limited. Materials and methods: Thirty edentulous patients had their denture‐supporting tissues scored by Kapur Index and their old dentures replaced. They received three brands of denture cushion adhesives (Fittydent^®, Protefix^® and Seabond^®) and were instructed to use them in a sequence according to the group they were randomly assigned to. Each brand of adhesive was used for 48 h on the lower denture according to the manufacturer’s suggestions. After each brand was used, participants spent 24 h without applying any sort of adhesive. Finally, a questionnaire evaluating and comparing the performance of each brand was filled out. Results: Denture adhesives generally improved patient satisfaction and masticatory ability, especially in participants with poor Kapur Index and those who reported a poor retention of their old dentures. Conclusion: Fittydent^® was the most preferred adhesive, showing the best retention and the longest duration of its effect, but also reported as difficult to remove from the denture‐bearing area.     

Effects of denture maintenance on satisfaction levels of Taiwanese elderly using removable partial dentures: a pilot study

doi: 10.1111/j.1741‐2358.2011.00500.x
Effects of denture maintenance on satisfaction levels of Taiwanese elderly using removable partial dentures: a pilot study Objective: The aim of this study was to evaluate the correlation between patient satisfaction with removable partial dentures and denture maintenance by patients, including regular application of denture adhesives and cleansers. Background: The success of removable partial dentures depends on patient satisfaction with dentures and their regular denture maintenance. Materials and methods: Demographic information, the Oral Impacts on Daily Performance (OIDP) indicator and details of denture maintenance (including the use of denture cleansers and adhesives) were collected from 193 (41.5% men and 58.5% women) participants by using questionnaires. A dentist performed oral examinations to evaluate denture function according to the OIDP items photographically and recorded the number of remaining teeth and Kennedy’s classification. Results: Most participants were satisfied with their removable partial dentures and tended to have higher satisfaction levels than the dentist’s estimation. Further, those using denture adhesives and cleansers had higher satisfaction levels than those not using such denture maintenance. Conclusions: Appropriate education regarding denture use is important because regular denture maintenance by patients affects their degree of satisfaction with dentures, as well as the dentist’s skill and the patient’s oral condition. Dentists could use this information to predict the potential success of dentures.     

In vivo assessment of the effect of an adhesive for complete dentures on colonisation of Candida species

doi: 10.1111/j.1741‐2358.2009.00345.x
In vivo assessment of the effect of an adhesive for complete dentures on colonisation of Candida species Objective: Denture adhesives have long been recognised by denture wearers as a useful adjunct to denture retention and stability. The objective of the present study was to evaluate, in vivo, the effect of a denture adhesive on oral quantities of Candida species by determination of absolute counts of colony‐forming units (CFU) per ml of saliva of individuals who use this denture adhesive for a period of 14 days. Materials and methods: Twenty‐four individuals were randomised in two equal groups of 12 (test and control), with the individuals of the test group using the adhesive for 14 days. Samples of saliva were collected from all individuals on days 0 (initial), 7 and 14. Aliquots of saliva were diluted and plated in duplicate on Sabouraud dextrose agar with chloramphenicol and incubated for 37°C for 48 h, the CFU/ml were counted in the individuals of each group and the data of each group were compared at the different time periods and analysed statistically by the non‐parametric Mann‐Whitney U‐test (α ≤ 5%). Results: There were no statistically significant differences between the test and control groups during the test periods. Conclusion: Within of the limitations of this study, the data suggested that the denture adhesive tested did not significantly alter the oral microbiota during the 14‐day trial period.     

Flexural and bond strengths of relined denture polymers assessed by four‐point bending tests and Weibull analysis

doi: 10.1111/j.1741‐2358.2011.00515.x Flexural and bond strengths of relined denture polymers assessed by four‐point bending tests and Weibull analysis Objectives: The aim of this study was to (1) investigate the flexural strengths of three denture resins i.e. heat, photopolymerised and microwaved and how it was affected by relining with auto‐ and visible light–polymerised hard reliners, (2) investigate the bond strengths between denture resins and hard reliners and (3) interpret the results of both tests by utilising Weibull analysis. Materials and methods: Specimens (65 × 10 × 2.5 mm) from denture resins, relined and bonded combinations were tested using a four‐point bending test in a universal testing machine and a crosshead speed of 5 mm/min. Ten specimens for each bulk resin and denture resin–reliner combination for a total of 150 were tested. Results: Statistical analysis indicated significant differences between bulk materials (p < 0.001) and between reliners (p < 0.001) for flexural and bond strength tests. Conclusion: It was concluded that (1) the four‐point flexural strength was different between the denture base materials, (2) flexure strength between bulk and relined or between relined with autopolymerised and photopolymerised bases was different, (3) flexural strength among relined denture bases was different and (4) bond strengths among relined denture bases were different.     

Effect of ill-fitting dentures on the swallowing duration in patients using polygraphy

doi: 10.1111/j.1741‐2358.2011.00536.x Effect of ill‐fitting dentures on the swallowing duration in patients using polygraphy Background: Surface electromyography (SEMG) has been widely used in the recent years to study swallowing physiology, offering a valid and reliable tool for identifying normal swallowing. The goal of our study was to assess the contribution of denture fitness in the age‐related increase of swallowing duration. Methods: Twenty denture wearers and 20 dentate individuals were analysed using SEMG and a computerised kinesiography of mandibular movement. Three spontaneous saliva swallowings were recorded for each patient with both their old and new prostheses. Three spontaneous saliva swallowings were recorded for each dentate person in two different recording sessions. Results: Old prosthesis mean swallowing time was 1.84 (SD ± 0.85) seconds while the new well‐fitting prostheses needed a 1.28 (SD ± 0.55) (p = 0.0009) swallowing time. The difference in swallowing time was significant (p = 0.01) between dentate subjects and individuals wearing an old prosthesis. No significant difference was found between dentate subjects and the same prosthesis wearers when a new well‐fitting prosthesis was worn. Conclusion: Data presented in this work suggest that part of the increased duration of swallowing showed by elderly and healthy people is because of incorrect an dental prosthesis. Prolongation of swallowing duration in the elderly population could be reconsidered in the light of the quality of dental device worn by the aged population.     

Relationship between salivary histatin 5 levels and Candida CFU counts in healthy elderly

Objectives: Few epidemiological studies have confirmed the antifungal activity of histatin 5 in saliva against Candida species. The purpose of this study was to examine the relationship between concentrations of histatin 5 and the number of cultivable Candida in saliva samples from elderly. Methods: Whole saliva samples were obtained from 124 elderly people, 65 years or older, living in a rural community. The concentrations of histatin 5 in saliva samples were determined by the enzyme‐linked immunosorbent assay (ELISA) using a monoclonal antibody. Total colony‐forming units (CFUs) were counted on a selective medium for Candida. Multiple linear regression analysis was performed to determine the independent contribution of explanatory variables to Candida CFUs using age, sex, histatin 5 concentration and type of denture prosthesis as independent variables. Results: Saliva samples from 104 subjects (84%) were candidal colony‐positive. The youngest group (65–69 years old) showed significantly smaller Candida CFU counts than those in the older group. The mean Candida CFU count of denture wearers was significantly higher than that of non‐denture wearers. Significantly negative associations were found between Candida CFU counts and histatin 5 level in the oldest group (p < 0.05) and in the full‐denture wearers (p < 0.01). Multiple linear regression analysis revealed that Candida CFU counts were mostly associated with type of dentures, followed by histatin 5 concentration. Conclusion: Possible activity of histatin 5 against Candida in whole saliva of elderly people was epidemiologically confirmed. The area covered by the prostheses was a strong factor associated with the Candida CFU count.     

Correlation between factors associated with the removable partial dentures use and Candida spp. in saliva

doi: 10.1111/j.1741‐2358.2010.00390.x
Correlation between factors associated with the removable partial dentures use and Candida spp. in saliva Objectives: To correlate the presence and number of Candida spp. in the saliva of wearers of removable partial dentures retained with precision attachments with the proportion of metal/acrylic resin present in the dentures. Methods: Saliva samples from 40 removable partial denture wearers (test) and one paired sample of individuals, non‐wearers of any type of removable denture (control) were collected, seeded, and the colony forming units of Candida counted and identified. The metal/acrylic resin proportion of each denture was quantified, using silicone plates pressed over each denture. Results: Candida spp. was found in the saliva of 80% of the individuals in the test group and 65% of the control, with C. albicans being the most prevalent species. The test group presented with the highest number of colony forming units of Candida per ml of saliva, and there was weak correlation between this number and the metal and resin area of the denture (Pearson’s coefficient of correlation). Greater prevalence and a higher number of colony forming units of Candida per ml of saliva occurred in removable partial denture wearers (p = 0.04) with a weak positive correlation between the metal and resin area and the number of colony forming units of Candida per ml of saliva. However, this correlation was more significant for the area of resin.     

The effect of long‐term disinfection procedures on hardness property of resin denture teeth

doi: 10.1111/j.1741‐2358.2011.00520.x The effect of long‐term disinfection procedures on hardness property of resin denture teeth Objective: The aim of the study was to evaluate the effect of long‐term disinfection procedures on the Vickers hardness (VHN) of acrylic resin denture teeth. Material and methods: Five acrylic resin denture teeth (Vipi Dent Plus‐V, Trilux–T, Biolux‐B, Postaris‐P and Artiplus‐A) and one composite resin denture teeth (SR‐Orthosit‐O) were embedded in heat‐polymerised acrylic resin within polyvinylchloride tubes. Specimens were stored in distilled water at 37°C for 48 h. Measurements of hardness were taken after the following disinfection procedures: immersion for 7 days in 4% chlorhexidine gluconate or in 1% sodium hypochlorite (CIm and HIm group, respectively) and seven daily cycles of microwave sterilisation at 650 W for 6 min (MwS group). In the WIm group, specimens were maintained in water during the time used to perform the disinfection procedures (7 days). Data were analysed with anova followed by the Bonferroni procedure (α = 0.01). Results: Microwave disinfection decreased the hardness of all acrylic resin denture teeth (p < 0.001). Immersion for 7 days in 4% chlorhexidine gluconate or distilled water had significant effect on the hardness of the acrylic resin denture teeth A (p < 0.01), and 1% sodium hypochlorite on teeth T (p < 0.01). All disinfection procedures decrease the hardness of the composite resin denture teeth (p < 0.01). Teeth O exhibited the highest and teeth V the lowest hardness values in the control group (p < 0.01). Conclusions: Disinfection procedures changed the hardness of resin denture teeth.     

Radiographic evaluation of alveolar ridge heights of dentate and edentulous patients

doi: 10.1111/j.1741‐2358.2010.00391.x Radiographic evaluation of alveolar ridge heights of dentate and edentulous patients Objective: To evaluate the reduction of residual alveolar ridge height on panoramic radiographs and the differences between denture wearers and non‐denture wearers. Materials and methods: The study consisted of 147 individuals (74 men and 73 women) [50 were denture wearers and 50 non‐denture wearers (examination groups) and 47 of them were dentate (control group)]. Individuals having diseases impacting on bone were excluded. Vertical measurements were made at 15 sites (central incisors, first premolars and molars at the left and right of both jaws and the distance between the zygoma/orbit). MANOVA (multi‐variate analysis of variation) was used for the statistical analysis of the results. Results: There were significant differences between the alveolar ridge heights of dentate and edentulous groups (p < 0.001). Between the denture wearer and the non‐denture wearer groups, there was significant difference in the lower jaw (p < 0.001), but no significant difference in the upper jaw (p = 0.635). There were also differences between men and women (p < 0.005) and upper and lower jaws at every measurement sites (p < 0.01). Conclusion: Reduction in residual alveolar ridge height was in close relation with gender, denture usage and edentulousness.     

Candida albicans biofilm formation on soft denture liners and efficacy of cleaning protocols

doi: 10.1111/j.1741‐2358.2011.00485.x
Candida albicans biofilm formation on soft denture liners and efficacy of cleaning protocols Objective: The aim of this study was to investigate Candida albicans biofilm formation on denture liners and to analyse the efficacy of cleaning protocols. Material and methods: Specimens were prepared from four silicone‐based soft denture liners. After artificial ageing and surface free energy determination, specimens were incubated with saliva (2 h) and Candida albicans ATCC 10231 for either short‐ (2.5 h) or long‐term (24 h) biofilm formation. Adherent cells were determined either after incubation of specimens with Candida albicans or after treatment with different denture cleaning protocols. Statistical analysis was performed using one‐way anova and the Games–Howell test (α = 0.05). Results: For both short‐ and long‐term biofilm formation, similar amounts of Candida albicans cells were found on the surface of the different liners (p = 0.295 and 0.178, respectively). For both short‐ and long‐term biofilm formation, the highest cleaning efficacy was observed for sodium hypochlorite (NaOCl; p < 0.01). The efficacy of the chemical denture cleaner in removing long‐term Candida albicans biofilms was significantly lower than the efficacy of removal by brushing (p < 0.001). Conclusion: Different silicone‐based soft denture liners yield similar Candida albicans biofilm formation on their surface. The highest efficacy for the removal of Candida albicans biofilms was identified for NaOCl. Chemical denture cleaners appear to have rather low efficacy to remove mature Candida albicans biofilms.     

Effect of denture adhesive on the micro-organisms in vivo

doi: 10.1111/j.1741‐2358.2010.00381.x Effect of denture adhesive on the micro‐organisms in vivo Background: Denture adhesives increase the retention and stability of dentures in edentulous patients, especially in cases where salivary flow is impaired or in the management of traumatised oral mucosa. Objectives: The effect of a denture adhesive on the oral flora at different time intervals. Method: Thirty denture‐wearing patients were involved in this study. While half of the group received a denture adhesive, the other half did not. At baseline, 1 and 2 months after delivering the dentures, smear samples were obtained from the saliva, palate and the dentures. Candida albicans, Candida krusei, Candida glabrata, Candida spp., Staphylococcus aureus, Moraxella catarrhalis, α‐haemolytic streptococci, β‐haemolytic streptococci, Pneumococcus aureus, S. anginosus, S. intermedius, S. constellatus, S. sanguis, S. gordonii, S. mitis, S. mutans, S. salivarius, and yeasts were investigated. The data were statistically analysed using anova and repeated measures. Results: Most types of the micro‐organisms were not seen and could not be analysed statistically except α‐haemolytic streptococci and C. albicans. No statistically significant difference was found for α‐haemolytic streptococci and C. albicans in saliva, palate and the denture at all time intervals. Conclusions: Prolonged use of the denture adhesive tested up to 2 months did not yield to increase in micro‐organisms of the oral flora.     

In vitro antiseptic properties of an ammonium compound combined with denture base acrylic resin

Background: Denture base acrylic resin is easily colonised by oral endogenous bacteria and Candida spp., and eventually by extra‐oral species such as Staphylococcus spp., Pseudomonadaceae or members of Enterobacteriaceae. This microbial reservoir can be responsive for denture related stomatitis and aspiration pneumonia, a life‐threatening infection especially in geriatric patients. However, the oral and denture hygiene of dependant elderly individuals is extremely poor. Objective: This in vitro study aimed to determine the per cent of a quaternary ammonium compound heat‐polymerised in acrylic resin necessary to obtain denture base displaying antiseptic properties. Design: Acrylic resin discs containing 2–50% ammonium polymer (Poly 202063A; 0% control) were soaked in artificial saliva for 4 weeks. Resin discs were incubated for 24 hours with Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa [37°C, brain–heart infusion (BHI) broth and phosphate‐buffered saline (PBS) buffer] and Candida albicans (30°C, Schaedler broth), in 15 ml (168 discs) and 600 μl (168 discs) of inoculum. Microbial growth was verified at t 0 hours and t 24 hours. Data were recorded as the mean of three colony forming unit (CFU) numerations. The borderline of antimicrobial effect was determined at 0.1% viable cells. Results: In 600 μl of PBS inoculum, resin specimens had a bactericidal effect (E. coli and S. aureus: 2%; P. aeruginosa: 10%) and a fungicidal effect (C. albicans: 50%). Long‐term stability and toxicity in vivo studies are now required. Conclusion: A 2% quaternary ammonium compound polymerised with a denture acrylic resin displayed antiseptic properties after a 4‐week soaking period in artificial saliva. Such antiseptic denture base could help geriatric patients to improve their oral health.     

The effect of immersion cleansers on gloss,colour and sorption of acetal denture base material

doi: 10.1111/j.1741‐2358.2012.00657.x The effect of immersion cleansers on gloss, colour and sorption of acetal denture base material Objective: To study the effect of peroxide and hypochlorite cleansers on gloss, colour and sorption of acetal denture resins. Materials and methods: Pink acetal and thermoplastic acrylic resins were evaluated. Thirty‐five specimens 39 × 39 × 1.8 mm of each resin were prepared. Each group of specimens (n = 7) was then immersed into cleansers for 100 days. Group I immersed in tap water, Group II in Corega Extradent for 5 min, Group III in Corega Extradent for 8 h, Group IV in NitrAdine? Seniors for 15 min and Group V in NaOCl 5.25%. Gloss, colour and weight measurements were taken initially and after 100 days. Data subjected to two‐way anova and Tukey’s test at α = 0.05. Results: Acrylic resin showed reductions of glossiness from ?5 to ?15 and acetal from ?0.2 to ?6. Colour changes (ΔΕ*) ranged from 2.64 to 7.64 for acrylic and 2.77 to 26.54 for acetal resin. Sorption for acrylic ranged from 11.64 to 17.06 μg/mm³ and 9.18 to 24.79 μg/mm³ for acetal resin. The results of (ΔΕ*) and sorption showed an interaction between denture resins and cleansers. Conclusions: The gloss of acetal resin was less affected by water, peroxides and NaOCl 5.25% compared with acrylic resin. Acetal resin showed clinically acceptable (ΔΕ*) whereas acrylic resin unacceptable ones for water and peroxide solutions. The immersion of acetal resin in NaOCl 5.25% showed clinically unacceptable (ΔΕ*) and higher sorption and should be avoided or should be managed with care.     

Cytogenetical damage in exfoliated oral mucosa cells in elderly people suffering denture stomatitis

doi:10.1111/j.1741‐2358.2009.00315.x
Cytogenetical damage in exfoliated oral mucosa cells in elderly people suffering denture stomatitis Objectives: The aim of this study was to evaluate comparatively the DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated oral mucosa cells from chronic denture stomatitis patients and healthy controls. Background: Over the course of ageing, individuals may develop many diseases such as denture stomatitis. Material and methods: A total of 23 chronic denture stomatitis patients and 23 controls presenting good oral conditions were included in this study. Individuals had epithelial cells mechanically exfoliated, placed in fixative and placed on clean slides, which were checked for nuclear phenotypes. Results: The results indicated no statistically significant differences (p > 0.05) of micronucleated oral mucosa cells from chronic denture stomatitis patients when compared to healthy controls. Nevertheless, chronic denture stomatitis was able to increase other nuclear alterations closely related to cytotoxicity such as karyorrhexis, pyknosis and karyolysis as depicted by significant differences (p < 0.05) between groups. No interaction was observed between smoking and chronic denture stomatitis. Conclusion: In summary, these data indicated that chronic denture stomatitis was able to induce cytotoxic effects as assessed by a micronucleus test.     

Flexural properties of repaired heat‐polymerising acrylic resin after wetting with monomer and acetone

doi:10.1111/j.1741‐2358.2009.00321.x
Flexural properties of repaired heat‐polymerising acrylic resin after wetting with monomer and acetone Objectives: Repair strength can be improved by treating fractured surfaces of a denture. Background: This study investigated flexural properties of heat‐polymerised acrylic resin specimens repaired with auto‐polymerising and visible light curing (VLC) resins after the repair surfaces were wetted with monomers or acetone. Materials and Methods: Fifty‐four specimens (65 × 10 × 2.5 mm) were prepared and 48 of them were sectioned to simulate denture fracture. Butt‐joint designed repair surfaces were wetted with heat‐, auto‐polymerising monomers and acetone for 180 s and repaired with auto‐polymerising and VLC resins. After repairs, specimens were subjected to three‐point bending test and flexural strength, strain, fracture load, modulus of elasticity and deflection values were recorded. Data were analysed with Student t and LSD tests (p ≤ 0.05). Results: Overall flexural strength, strain, fracture load and deflection values of specimens repaired with VLC resin were significantly higher than the specimens repaired with auto‐polymerising resin for all types of wetting agent (p < 0.05). Within the wetting agents, heat‐ and auto‐polymerising monomers produced the best mechanical properties, while wetting with acetone did not provide superior effect over both monomers. Conclusion: In clinical use, wetting the repair surfaces may result in stronger repairs. The use of bonding agent in VLC resin repairs in combination with wetting agent results in improved flexural properties.     

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

doi: 10.1111/j.1741‐2358.2010.00438.x 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 × 4 mm) of Elite Soft Relining (ES) and Mucopren Soft (MS) were randomly immersed in distilled water at 37°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 (μ =8.79 ± 7.36); T15 (μ = 4.23 ± 2.62) and T183 (μ = 8.78 ± 3.16), MS presented a higher increase in hardness than ES. After T7, MS underwent an increase in roughness (μ = 0.09 ± 0.80); ES underwent a decrease (μ = ?0.08 ± 0.16). RC caused the smallest variation in roughness. After T15, both materials presented an increase in roughness. After T183, ES (μ = ?0.30 ± 0.48) presented a higher roughness variation than MS (μ = ?0.07 ± 0.32). Hypochlorite caused an increase in roughness (μ = 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.