denture - induced stomatitis ( atrophic chronic candidiasis ) is an inflammatory lesion of 
 the denture bearing mucosa that affects approximately 50% of patients wearing maxillary 
 complete dentures , and has a 
 multifactor etiology .
factors of particular significance are trauma caused by the 
 denture itself , infection by candida , poor denture hygiene , continuous denture wear , and 
 dietary and systemic factors , including suppressed immunocompetence .
especially elderly people wearing 
 dentures or patients with metabolic diseases , such as diabetics , organ transplant 
 patients , cancer patients or patients on chronic antibiotic treatment have an increased 
 risk for developing oral candidiasis .
biofilm found on dentures consists of a complex mixture of fungi and bacteria and 
 desquamated epithelial cells .
this 
 biofilm act as a protective reservoir for oral microorganisms , and candida 
 albicans and other species of yeast found in biofilm have been reported as 
 important agents for the installation , maintenance and exacerbation of denture 
 stomatitis .
scanning electron microscopic evaluation of dentures retrieved from patients 
 suffering from denture stomatitis demonstrates that candida biofilm not 
 only colonizes the surface , but also penetrate the cracks and imperfections of the 
 denture material .
, also other pathogenic and opportunistic 
 microorganisms have been isolated from patient 's dentures which include 
 staphylococcus sp . , streptococcus sp . and pseudomonas 
 sp .. moreover , the 
 colonization of oral surfaces , including denture - seating surfaces , could serve as a 
 reservoir for disseminated infections , such as gastrointestinal infections .
even respiratory pathogens that are 
 uncommon in the oral flora have been isolated from dentures , including 
 escherichia coli , klebsiella pneumoniae , mrsa or 
 methicillin - resistant staphylococcus aureus and 
 enterobacteria .
the presence 
 of these bacteria increases the risk of aspiration pneumonia and/or aspiration 
 pneumonitis , in particular when swallowing disorders are observed ( e.g. : in patients 
 with neurological disorder including peripheral or central neuromotor disability , such 
 as cerebral palsy , stroke , parkinson 's disease , alzheimer 's disease or down 
 syndrome ) . for
the above 
 described reasons , adequate removal of pathogenic biofilm present on dentures should be 
 recommended as a routine practice .
the efficacy of several denture cleansers has been clinically evaluated in a number of 
 approaches , and commercially available denture cleansing products are generally not very 
 efficient in denture biofilm control . in addition , some of these cleansers are either 
 corrosive or change the colour or hardness of the polymer after repeated use .
the ideal denture maintenance product must be effective in the 
 removal of organic and inorganic deposits , have antibacterial and antifungal biofilm 
 removal properties , be non - toxic to humans , compatible with the denture materials 
 including metals , easy to handle and also have a low cost .
the aim of this study was to evaluate the clinical 
 efficacy of a novel disinfecting cleaning tablet for complete denture cleansing , medical 
 interporous ( msi laboratories ag , vaduz , liechtenstein ) , in terms of 
 denture biofilm removal and antimicrobial action in denture wearers .
this study was conducted with 40 complete denture wearers ( 14 men and 26 women ) with a 
 mean age of 62.39.0 years ( range : 45 to 70 years ) .
dentures were inserted at least 1 
 year ( mean 5.54.8 years ) prior to the study and were made from heat - polymerized acrylic 
 resin .
this research 
 study was approved by the institutional research ethics committee ( process number 
 2007.1.207.58.4 ) .
patients were informed of the nature of the investigation , and written 
 informed consent was obtained prior to enrolment .
exclusion criteria were : time of denture use less than one year and absence of biofilm 
 on internal surface of upper dentures during the first examination .
only subjects wearing upper complete dentures 
 with scores of " 1 " or greater were selected . in other words ,
volunteers were instructed to clean their dentures according to two methods : 1 ) control : brushing 3 times a day using a denture brush ( denture - condor s.a .
, so 
 bento do sul , sc , brazil ) and tap water following meals ( breakfast , lunch and 
 dinner ) ; 2 ) experimental : brushing the denture using the denture brush and tap water following 
 meals ( breakfast , lunch and dinner ) , and treating the denture with medical 
 interporous denture tablets , by immersing the denture into 150 ml of 
 lukewarm water and then adding one tablet .
the denture was then allowed to soak in the 
 solution for at least 15 min once a day for 21 days .
after treatment , the denture was 
 removed from the solution and rinsed vigorously under running water before replacing 
 back in the mouth .
the 40 patients were randomly distributed to each group and received verbal information 
 and practical demonstration of both control and experimental techniques .
after 
 participants had received their denture maintenance instructions and hygiene materials , 
 disclosure of the internal surface of maxillary denture of each participating denture 
 wearer was assessed using a 1% neutral red solution .
the disclosed dentures were then brushed until complete removal 
 of disclosed biofilm ( biofilm free ) . for evaluation of the efficacy in the removal of 
 biofilm , after 21 days of the use of both denture maintenance methods ( control and 
 experimental ) ,
the internal surfaces of upper dentures were disclosed again by 1% 
 neutral red solution .
the surfaces were then photographed ( digital camera canon eos 
 digital rebel ef - s 18 - 55 ; and flash : canon mr-14 ex , canon inc . ,
the camera was fixed on a stand ( cs-4 
 copy stand , testrite inst .
after quantification , biofilm 
 was eliminated by brushing with the denture brush and liquid soap ( job qumica , produtos 
 para limpeza ltda .
, monte alto , sp , brazil ) . photographs were transferred to a computer and the total surface area and the areas 
 corresponding to the stained region were measured using image processing software ( image 
 tool 2.02 , uthsc , san antonio , texas ) .
biofilm percentage was calculated using the 
 relation between biofilm area multiplied by 100 , and total surface area of the denture 's 
 internal base . for the microbiological analysis , at the end of the 21 days evaluation period ,
serial dilutions were prepared in pbs ( 10 ) and 
 cultivated in chromagar 
 candida ( chromagar , paris , france ) culture medium ( cm ) under laminar 
 flow , in duplicate at 37c for 48 h. the counting of the number of colony - forming units 
 ( cfu ) of yeast - like fungi was performed and the identification was carried out on the 
 basis of the macroscopic morphology and use of code of colors ( candida albicans 
 -green ; candida dubliniensis - green ; candida 
 glabrata - purpura ; candida tropicalis - blue ; 
 candida parapsilosis - white ) .
the identity of the isolated yeasts 
 was confirmed by the tests of tube formation of germination ( gt ) , chlamydoconidia and 
 tests of fermentation and assimilation .
the influence of the treatments on the denture biofilm percentage was assessed with an 
 independent sample t - test .
the homogeneity of the variances was tested with a levene 's 
 test and normality of the residuals was tested with a shapiro - wilk test ( sw ) . a 
 significance level of p<0.05 was used .
the data were transformed to 
 their square root to meet the assumptions . in the tables ,
the back - transformed mean 
 values together with their 95% confidence interval are shown .
the analysis of the antimicrobial action was performed after processing the original 
 data ( cfu ) in log 10 .
counts were not normally distributed 
 and were compared by the mann - whitney test .
table 1 shows the biofilm percentage in the 
 internal surface of the upper complete denture after the use of the control method and 
 after the use of the medical interporous denture tablets ( experimental ) . 

the percentage was obtained from the measurement of the total and disclosed area with 
 biofilm .
total amount of denture biofilm presence ( as percentage of total denture surface 
 area ) in the control group ( control ) and after treatment ( experimental ) with 
 medical interporous dentures tablet ( mean , n=20 ) ci : confidence interval the data were transformed to their square root prior to the analysis to obtain 
 homogeneity of the variances ( f1,38=1.797 , p=0.188 ) and 
 normality of the residuals ( sw40=0.946 , p=0.056 ) .
an 
 independent t - test revealed a significant lower biofilm percentage for the experimental 
 group [ 4.7 , 95% confidence interval ( ci ) 2.4 to 7.9 ] in comparison with the control 
 group ( mean 37.5 , 95% ci 28.2 to 48.1 ) ( t38=7.996 , p<0.001 ) .
table 2 presents the total cfu counts ( in log 
 10 ) of yeast obtained for the control group ( cg ) and for the experimental group ( mi ) .
a 
 significant reduction of yeast cfu could be found after treatment with medical 
 interporous denture tablets as compared to the control group .
the data 
 of table 2 were analyzed by the mann - whitney 
 test , which showed significant difference between the groups .
total of cfu ( log 10 ) of the yeasts after the use of the brushing and water 
 ( control group ) and after the use of the medical interporous dentures 
 tablet ( experimental group ) cg : control group ; mi : medical interporous dentures tablet
the study of oral hygiene in elderly denture wearers is becoming increasingly important 
 because of the increasing numbers of elderly people in the world . today
, approximately 
 600 million people are aged over 60 years , and this number is estimated to double by 
 2025 , 80% of which live in developing countries . in brazil , by the year 2050 , over 100 
 million people will be old - aged . 

microbial biofilm on the fitting surface of the denture is one of the principal causes 
 of denture stomatitis .
the 
 correlation between poor denture cleanliness and denture stomatitis is statistically 
 significant according to kulak - ozkan , et al .
removal of the denture biofilm by means of good denture 
 hygiene is important in the prevention of the denture stomatitis , in aesthetic aspects 
 and in the maintenance of a healthy mucosa .
efficient biofilm control by mechanical or chemical denture 
 cleansing has produced significant resolution of this oral disease .
however , the incidence of denture 
 stomatitis is still significant affecting 11 - 67% of denture wearers and recent studies 
 indicate that 1 in every 3 removable denture wearers in the united states suffers from 
 denture stomatitis
these type 
 of denture cleansers can be divided into five groups : alkaline peroxides , alkaline 
 hypochlorite , diluted organic and inorganic acids , disinfectants and enzymes . while chemical biofilm control is a useful and appropriate 
 procedure , such treatment
should always be accompanied by mechanical control of biofilm 
 in the fitting surface of the denture , and brushing the fitting surface of the prosthesis should be 
 indicated as an essential technique of hygiene , at least for patients with motors 
 disabilities . because of this evidence , the association of both methods was used in the 
 present study in the experimental group ( brushing and immersion in medical 
 interporous for 15 min ) .
dentures are made of poly - methyl methacrylate ( pmma ) and all of them become quickly 
 colonized by various microorganisms once they are being placed in the mouth .
these 
 microorganisms , including bacteria , fungi and viruses , initially adhere to the surface 
 of the denture material and subsequently penetrate into the dentures via a complex of 
 pores and tracks formed by the release of gases during the construction polymerization 
 process .
the dentures in this study were at least 1 year old 
 once it is necessary for patients to be really adapted to the daily use of the denture , 
 which ensures the formation of biofilm .
moreover , with the continuous use , the resin 
 looses gradually its polished surface , which also contributes to the buildup of biofilm 
 and penetration of microorganisms in the porous of the acrylic resin .
so , the 
 effectiveness of the product in biofilm removal , as well as its antimicrobial action can 
 be evaluated . in another study , jeganathan , et al .
( 1996 ) suggested that the increasing occurrence of stomatitis in 
 some of the analyzed denture wearing patients may be related to the age of the denture : 
 the denture may become traumatic because of old age and the surface may present 
 porosities that make it more difficult to keep clean .
this may partially explain the 
 varying number of cfu of candida albicans in the experimental group in 
 this present study .
the overall objective of immersing a denture in a cleaning maintenance solution is to 
 obtain a clean but also decontaminated prosthesis through the destruction of 
 microorganisms by means of the chemical actions including the effervescency properties 
 of the cleanser .
it has been shown 
 previously that 24 h accumulations can be removed moderately effectively after 15 min of 
 immersion and completely with overnight soaking .
( 2008 ) affirmed that the contact time with nitradine 
 ( msi laboratories ag , vaduz , liechtenstein ) needs to be sufficiently long ( i.e. , at 
 least 10 - 15 min ) in order to obtain meaningful reductions , and this may be attributed to 
 the time needed for the disinfectant to penetrate in to the biofilm . in the present 
 study ,
the percentage of biofilm in the experimental group has diminished substantially 
 ( from 37.5% to 4.7% ) in comparison to the control group after 21 days of use .
although 
 the use of nitradine is indicated daily for 2 weeks , a period of 21 days 
 was used in this study as a parameter of comparison with others studies found in 
 literature .
( 2009 ) , while evaluating the mechanical method , found significant 
 differences between the control and experimental groups , and brushing with experimental 
 dentifrice presented greater effectiveness in removing the biofilm . hence , regular overnight soaking in this product may increase the antimicrobial 
 potential even further , clean the denture completely and leave polished and shiny 
 surfaces .
( 2000 ) in addition to the usual instructions in oral hygiene that should be given to 
 patients wearing prosthesis , the use of disclosing solutions to identify biofilm 
 accumulations was demonstrated .
since mature biofilm is much more resistant to removal 
 than the 24 h biofilm , the 
 quantification of the biofilm can be regarded as a good outcome measurement for denture 
 hygiene .
the use of neutral red solution is justified by its high affinity to oral 
 biofilms and the ease of removal . in 
 addition ,
photography combined with 
 quantitative analysis was employed 
 to standardize an objective evaluation method .
a limitation of most biofilm measurement 
 techniques , including the present method is the two dimensional nature of the recording . 
 the use of a disclosing method appears to present no disadvantage when compared with the 
 biofilm weight .
furthermore , biofilm 
 staining is the most commonly used technique for denture biofilm 
 quantification , and hence , 
 provides a more efficient method if data need to be compared with previous studies .
the 
 analysis used in this study was based on biofilm quantification on the internal surface 
 of the maxillary complete denture , in accordance with the studies by paranhos , et 
 al .
( 2007 ) , keng and 
 lim ( 1996 ) , sheen , et 
 al .
this surface has 
 greater potential for build - up of pathogenic micro - organisms and the consequent 
 development of denture stomatitis . as suggested by paranhos , et al .
( 2007 ) , we did not measure the external 
 surface , since it accumulates much less biofilm .
the ideal denture cleanser should be efficient in removal of organic and inorganic 
 depositions , non toxic , low cost , ease to use and reduce the amount of biofilm , stain 
 and food of the dentures surface .
we observed a significant difference between the 
 control group and the experimental group in reduction in candida sp 
 however with some variability .
this could be related to the variability in the 
 number of cfu of candida sp , between the periods of study and the 
 subjects , as previously described by with gornitsky , et al .
medical interporous denture tablets contain nitradine , a 
 disinfecting formula that demonstrated high in vitro biofilm removal 
 activity against a variety of micro - organisms , namely candida albicans , 
 pseudomonas aeruginosa , staphylococcus aureus , including the mrsa type , and 
 viruses .
the efficacy of these tablets in reducing the biofilm 
 percentage may also be due to the presence of sodium lauryl sulfate ( sls ) in its 
 formula , moore , et al .
( 1984 ) 
 reported that in a group of six cleansers alkaline peroxide cleansers , only two of them 
 had a superior performance against yeasts , maybe because of the presence of sls .
sls is 
 a detergent used to solubilize protein in a variety of biochemical analysis 
 techniques .
( 2008 ) , while testing 
 the modified robbins device to study the in vitro biofilm removal 
 efficacy of nitradine found that the number of c. albicans 
 biofilm cells on various materials was reduced by 3 - 4 log units after a single 
 15 min treatment , while reductions of c. 3 log units were obtained for mrsa and 
 pseudomonas aerouginosa .
this study showed the efficacy of 
 nitradine and the optimal conditions for the application of this 
 disinfectant .
( 1988 ) showed that 
 brushing combined with soaking treatment removed significantly more organisms than 
 brushing alone : the level of microorganisms recovered from the prosthesis were 
 significantly lower , which confirms the results from our current study . in the same 
 study , dills , et al .
( 1988 ) observed 
 that the denture cleansers tested were not selective in its antimicrobial action , and 
 that denture cleanser soak treatment displayed a broad spectrum activity in eliminating 
 gram negative anaerobic rods , gram positive facultative cocci , and gram 
 negative anaerobic cocci .
these results support the need to use a 
 denture disinfectant in addition to brushing the prosthesis for proper denture 
 hygiene .
since most elderly people do not know how to keep dentures clean , knowledge of the 
 efficacy of different denture maintenance protocols is of importance to improve the 
 quality of life of these dentures wearing patients and also the durability of the denture itself will be prolonged . 

this study suggests that nitradine - based disinfecting cleaning tablets are 
 efficient in removal of denture biofilm .
so , the medical interporous product can be useful clinically , 
 especially for institutionalized patients , frail elderly patients in nursing homes , 
 patients undergoing cancer treatment , and hiv infected patients , and seem to be 
 effective against methicillinresistant staphylococcus aureus ( mrsa ) , 
 which can cause a type of staph infection that is hard to treat because it can not be 
 killed by many common antibiotics .
moreover , the " tablet form " application is very easy - to - use and a consumer friendly 
 method , which is another benefit for the elderly denture wearer .
additional studies are 
 currently ongoing to address the physicochemical properties of the medical 
 interporous as well as its mechanism of action in the prevention of 
 denture stomatitis symptoms .
microbial denture biofilm counts were substantially higher in the control method 
 ( denture brushing with tap water ) , when compared with the treatment based on denture 
 brushing and the immersion in medical interporous denture tablets . 

therefore , these tablets should be recommended as a routine denture maintenance method 
 for the prevention of the development of microbial biofilm - induced denture 
 stomatitis .
tom coenye and prof . bart vande vannet for critical 
 review of the paper content .
 objectivethis study evaluated the efficacy of nitradinetm - based disinfecting 
 cleaning tablets for complete denture , in terms of denture biofilm removal and 
 antimicrobial action . 
 material and methodsforty complete denture wearers ( 14 men and 26 women ) with a mean age of 62.39.0 
 years were randomly assigned to two groups and were instructed to clean their 
 dentures according to two methods : brushing ( control ) - 3 times a day with denture 
 brush and tap water following meals ; brushing and immersion ( experimental ) - 
 brushing the denture 3 times a day with denture brush and tap water following 
 meals and immersion of the denture in nitradinetm - based denture tablets 
 ( medical interporoustm ) . 
 each method was used for 21 days . 
 denture 
 biofilm was disclosed by a 1% neutral red solution and quantified by means of 
 digital photos taken from the internal surface before and after the use of the 
 product . 
 microbiological assessment was conducted to quantify candida 
 sp . 
 
 resultsan independent t - test revealed a significant lower biofilm percentage for the 
 experimental group ( 4.7 , 95% ci 2.4 to 7.9 ) in comparison with the control group 
 ( mean 37.5 , 95% ci 28.2 to 48.1 ) ( t38=7.996 , p<0.001 ) . 
 a significant reduction 
 of yeast colony forming units could be found after treatment with medical 
 interporoustm denture tablets as compared to the control group 
 ( mann - whitney test , z=1.90 ; p<0.05 ) . 
 conclusionthe present findings suggest that nitradinetm - based disinfecting 
 cleaning tablets are efficient in removal of denture biofilm . 
 in addition , a clear 
 antimicrobial action was demonstrated . 
 therefore , they should be recommended as a 
 routine denture maintenance method for the prevention of the development of 
 microbial biofilm - induced denture stomatitis . 
INTRODUCTION
MATERIAL AND METHODS
RESULTS
DISCUSSION
CONCLUSION
ACKNOWLEDGEMENTS