Denture stomatitis–yeast occurrence and the pH of saliva and denture plaque

abstract – The study comprised 30 denture wearers with generalized simple or granular inflammation in the palate and 30 without (controls). Yeasts, mostly Candida species, were cultivated from the maxillary dentures of all subjects with inflammation and of 23 controls. Hyphae were found in the maxillary denture smears from 28 subjects with inflammation and from 18 controls. Thus it seems unjustified to consider the occurrence of hyphae pathognomonic of denture stomatitis. The pH of whole saliva did not differ in the two groups (inflammation: mean pH 6.5, control: 6.6). There was no clear relation, between the pH of resting saliva and the amount of fungal cultures. Thirty minutes after a mouth rinse with 10 ml of a 25% sucrose solution, the mean saliva pH had dropped equally in both groups. With regard to the denture plaque, samples taken 40 min after the rinse indicated a more pronounced acid production in the plaque associated with inflammation. The pH of "resting" plaque was also lower in the inflammation than in the control group (mean maxillary pH 5.7 and 6.3, respectively, α= 0.002). No association was found between the pH and the occurrence of hyphae in "resting" denture plaque. This supports the view that the pH is of no major importance for filamentation in vivo .     

Oral hygiene habits, denture plaque, presence of yeasts and stomatitis in institutionalized elderly in Lathian, Scotland

The purpose of the present study was to examine the relation between oral hygiene habits, denture plaque, presence of yeasts and stomatitis in institutionalised elderly. A sample of 201 residents, 48-99 yr of age (mean age 82 yr), was selected from four different institutions in Lothian, Scotland. Clinical recordings were carried out under standardised circumstances using well recognised indices. Information about oral hygiene habits was obtained through structured interviews conducted immediately before the clinical examination. A multivariate analysis, principal component, was carried out on the correlated five maxillary denture plaque scores and two components, accounting for 74% and 12% of the variation, were identified. Using these two independent variables, an analysis of variance was carried out testing for significance between the four effects: soaking habits, brushing habits, denture stomatitis and growth of yeasts in the palate together with their interactions. The analysis showed a significant relation between maxillary denture plaque, soaking habits and the presence of denture stomatitis. There was no relation between denture plaque and brushing habits or between denture plaque and growth of yeasts.     

Quantitative relationship between yeast and bacteria in denture-induced stomatitis

Quantitative cultural studies of yeasts and bacteria were made from 7-day-old denture plaque accumulate on pieces of self-adhesive tape stuck on the fitting surface of the maxillary denture in 17 edentulous subjects with healthy oral mucosa and in 27 patients affected with denture-induced stomatitis. Significantly higher numbers of yeasts and bacteria were cultured in the stomatitis patients than in the controls. This indicates that the rate of plaque formation is increased in patients with denture-induced stomatitis. Yeasts usually constituted less than 1% of the anaerobic bacterial counts, but the percentage of yeasts was significantly higher in the stomatitis patients than in the controls. There was a significant correlation between initially higher yeast counts and improvement of the clinical condition of the palatal mucosa following antimycotic treatment. In some patients only bacteria were grown and antimycotic treatment had no effect. The study supported the contention that yeast antigens and toxins of denture plaque are significant factors in initiation and maintenance of denture-induced stomatitis. However, bacteria may also be involved as pathogens.     

Risk factors associated with denture stomatitis in the United States

BACKGROUND: This study reports denture stomatitis (DS) prevalence from a large USA probability sample from the National Health and Nutrition Examination Survey, 1988-1994 (NHANES III). METHODS: Oral examinations were performed on 3450 individuals 18-90+ years of age (mean: 59.2; SD: 0.50 years), 57.7% male and 42.3% female. Multivariable logistic regression models were fitted for DS using sociodemographic, denture quality, blood analytes, alcohol and tobacco use, history of diabetes, and current antibiotic use as covariates. Odds ratios (OR), adjusted for other covariates in each model (AOR) are presented. RESULTS: Of 3450 removable denture wearers, 963 (27.9%) had DS. DS prevalence was associated with wearing maxillary (AOR: 6.20) and mandibular (AOR: 5.21) complete dentures continuously; smoking >/=15 cigarettes day (maxillary complete: AOR = 1.31; mandibular complete: AOR = 1.50; maxillary partial: AOR = 2.04); vitamin A deficiency (mandibular complete: AOR = 5.97; maxillary partial: AOR = 5.67; mandibular partial: AOR = 24.42). Maxillary dentures with inadequate relines had approximately half the OR of DS than those with adequate relines (maxillary complete: AOR = 0.42; mandibular complete: AOR = 0.50). CONCLUSIONS: Denture stomatitis prevalence is associated with the amount of tissue covered by dentures, low vitamin A levels, cigarette smoking, and constant denture wear.     

Assessment of denture plaque pH in subjects with and without denture stomatitis

abstract — To evaluate the "resting" pH and induced pH changes in denture plaque, soft deposits were collected from the fitting surface of the denture, pooled and suspended in water. Plaque pH was determined with microelectrode equipment before and after mouth rinsing with a sucrose solution. A characteristic level in the "resting" pH of denture plaque was found in most of 12 subjects tested. pH values below the baseline level were recorded for more than 2 h after a rinse. The pH depressions were more pronounced in maxillary than in mandibular plaque. Further, the pH minima tended to be lower in subjects with denture stomatitis than in. controls. No clear relationship could be established between the "resting" pH and the concentration of Candida hyphae in denture smears or palatal inflammation.     

Capacity of denture plaque/biofilm removal and antimicrobial action of a new denture paste

The efficacy of a paste for complete dentures was analyzed in terms of denture plaque/biofilm removal and antimicrobial action against specific microorganisms by determination of colony forming units of mutans group streptococci and yeast from 120 full denture wearers with a healthy palatine mucosa. The patients were given a questionnaire to evaluate the experimental product in terms of important characteristics. The paste was widely accepted by the patients, and effective in denture plaque removal and antimicrobial action. The species of yeasts most frequently isolated were C. albicans, C. tropicalis and C. glabrata. We conclude that it is possible for complete denture wearers to keep their dentures clean with the regular use of a paste-like hygienic product.     

Quantitative relationship between yeasts and bacteria in denture-induced stomatitis

Abstract – Quantitative cultural studies of yeasts and bacteria were made from 7-day-old denture plaque accumulated on pieces of self-adhesive tape stuck on the fitting surface of the maxillary denture in 17 edentulous subjects with healthy oral mucosa and in 27 patients affected with denture-induced stomatitis. Significantly higher numbers of yeasts and bacteria were cultured in the stomatitis patients than in the controls. This indicates that the rate of plaque formation is increased in patients with denture-induced stomatitis. Yeasts usually constituted less than 1% of the anaerobic bacterial counts, but the percentage of yeasts was significantly higher in the stomatitis patients than in the controls. There was a significant correlation between initially high yeast counts and improvement of the clinical condition of the palatal mucosa following antimycotic treatment. In some patients only bacteria were grown and antimycotic treatment had no effect. The study supported the contention that yeast antigens and toxins of denture plaque are significant factors in initiation and maintenance of denture-induced stomatitis. However, bacteria may also be involved as pathogens.     

Assessment of denture plaque pH in subjects with and without denture stomatitis.

To evaluate the "resting" pH and induced pH changes in denture plaque, soft deposits were collected from the fitting surface of the denture, pooled and suspended in water. Plaque pH was determined with microelectrode equipment before and after mouth rinsing with a sucrose solution. A characteristic level in the "resting" pH of denture plaque was found in most of 12 subjects tested. pH values below the baseline level were recorded for more than 2 h after a rinse. The pH depressions were more pronounced in maxillary than in mandibular plaque. Further, the pH minima tended to be lower in subjects with denture stomatitis than in controls. No clear relationship could be established between the "resting" pH and the concentration of Candida hyphae in denture smears or palatal inflammation.     

Clinical and microbial evaluation of treatment regimens to reduce denture stomatitis

This study evaluated the effect of an antimicrobial mouthrinse, denture soft relines, and a placebo rinse on the clinical findings and microbial flora of 78 patients with denture stomatitis. For 28 days the study and control groups performed oral rinses and denture soaks. Reline group patients had maxillary denture soft relines that were changed every 7 days. At the end of the study, the mean severity of denture stomatitis was significantly less in the groups that used the study rinse (P less than 0.01) and received denture relines (P less than 0.05) compared to the control. Analysis of variance revealed significant differences in ranked adjusted percentage counts in two out of 13 denture plaque organisms investigated (Fusobacterium nucleatum [P less than 0.05] and total Bacteroides [P less than 0.05]), with the antiseptic rinse producing the lowest count. Yeast populations were reduced, but not significantly (P = 0.07). In the absence of other mechanical denture hygiene procedures, the antiseptic rinse and relines were equally effective in reducing denture stomatitis and potential pathogens of denture plaque flora.     

Denture plaque and palatal mucosa in denture stomatitis: scanning electron microscopic and microbiologic study

Denture plaque is an etiologic factor in denture stomatitis. In this study, denture and mucosa samples from nine patients were examined in the SEM and processed for microbiologic cultures. Denture plaque in patients with denture stomatitis showed a considerable thickness containing cocci, filaments, rods, yeasts, and desquamated epithelial cells. Some microorganisms were revealed in the connective tissue in one patient and phagocytizing polymorphonuclear leukocytes were found in the palatal mucosa of the patients with denture stomatitis.     

Regional variations in viable bacterial and yeast counts of 1-week-old denture plaque in denture-induced stomatitis

Abstract – Quantitative cultural studies of yeasts and bacteria were made from 1-week-old denture plaque accumulated on pieces of self-adhesive tape stuck on the fitting surface of the maxillary denture in four well-defined locations. A tape piece was also stuck on the buccal denture flange. The cultural examinations were made in 15 patients with denture-induced stomatitis which affected most of the denture-bearing mucosa. There was no significant difference of the bacterial counts from the different sampling areas although the variations between patients was significant. The yeast counts from the test area located on the buccal denture flange were significantly lower than those originating from the fitting denture surface. On the other hand, there was no significant variation of the yeast counts when comparing the test areas of the fitting denture surface. In 12/15 of the patients yeast counts of 10³/cm² were obtained from the fitting denture surface. The results indicate that the environmental conditions beneath a denture base predispose for yeast colonization and are different from those present on the buccal flange.     

A 3-months''study of enzymes as denture cleansers

It was the purpose of the study to test the efficacy of dissolvent tablets containing mutanase and protease in removing denture plaque. The study group consisted of forty institutionalized geriatric denture wearers, who were assigned randomly into an enzyme group and a placebo group. Enzyme tablets and placebo for denture soaking were administered by the nurses. The dentures were immersed for 15 min once daily for three months. The amount of denture plaque, the clinical condition of the palatal mucosa, and the concentration of yeasts and bacteria in mucosal and denture smears were recorded before, during, and after the experimental period. The study was designed and carried out as a double-blind study. After denture soaking for six weeks a significant reduction of the amount of denture plaque and improvement of the clinical condition of the palatal mucosa was recorded. After denture soaking for twelve weeks the conditions had improved further when comparing the enzyme group with the placebo group.     

The effect of verbal information and demonstration on denture hygiene in elderly people

The purpose of the present study was to investigate the effect of two oral hygiene information programs on denture hygiene. The programs were provided individually to healthy elderly denture wearers. Totally, 150 edentulous persons between 67 and 89 years of age were selected and randomly assigned to two experimental groups and one control group. In one test group (INFO) the participants were only given individual verbal information on how to remove denture plaque. The participants of the second test group (DEMO) received individual demonstration of denture cleaning in addition. One hundred and thirty-eight persons completed the study. The percentage plaque covering the maxillary denture base was assessed by a morphometric point-estimator scoring method at the start of the study and after 14 and 180 days. Verbal information resulted only in a short-term effect (14 days), whereas demonstration on how to remove denture plaque gave long-term (180 days) improvement of denture hygiene.     

Evaluation of a dehydrated test strip, Microstix®-Candida, for detection of Candida-induced denture stomatitis

abstract – The outgrowth of yeasts from the fitting surface of the maxillary denture and the palatal mucosa was estimated in 63 denture wearers by means of smears and by culture on Microstix®-Candida (M–C). There was a significant relationship between the concentration of yeasts as assessed by smears and by M–C. There were confluent spots on M–C, indicating large numbers of yeast cells, in 81 % of 37 denture wearers with a positive microscopic diagnosis for Candida-induced denture stomatitis, whereas there were confluent spots on M–C in only one of 26 denture wearers with a negative microscopic diagnosis for infection. It is concluded that the M–C test system seems to have sufficient diagnostic sensitivity to be an alternative to the smear for establishing the diagnosis of Candida-induced denture stomatitis.     

Effect of denture surface glazing on denture plaque formation

This study evaluated, in vivo, the efficacy of a denture glazing material (Palaseal) in modifying plaque colonization of dentures. Ten subjects were selected and received maxillary temporary partial removable dentures, with complete acrylic palatal coverage. The right half of the fitting surface of the denture bases were glazed with Palaseal, whereas the other half was not glazed. One month after insertion, two fragments of the resin base of all dentures were removed (one from the glazed side and another from the non-glazed side). These samples were prepared and examined by scanning electron microscopy. Three months after insertion, other fragments were obtained and analyzed. Microscopic observation at 1 month revealed that, for all patients, the plaque film was thinner on the treated side in comparison to the non-treated side. However, at the 3-month evaluation, some areas of the glaze showed cracking, and both glazed and non-glazed sides were covered by a dense bacterial plaque film. In conclusion, the findings of this clinical experiment showed that glazing denture's fitting surface did not prevent bacterial colonization, but favored plaque removal while the glaze layer remained intact. After three months, glaze cracks created microretentive areas that increased plaque accumulation.     

Status and treatment of denture stomatitis patients: a 1-year follow-up study

Abstract – The material comprised 48 patients, 19 exhibiting atropiiic and 29 hyperplastic denture stomatitis. Twenty-seven patients with healthy mucosa served as a reference group. Past history, resilience of the mucosa, denture function and scores of palatal erythema, plaque and yeasts were recorded. The therapeutic program included new dentures, surgical and nystatin treatment, hygienic instruction and nutritional advice. The results concerning past history showed significantly more smokers, more patients with recurrent urinary tract infections in combination with prolonged antibiotic therapy, and more patients wearing their dentures at night in the denture stomatitis group. Nystatin treatment did not affect the healing of palatal erythema evaluated after 1 year. The treatment program evaluated after 1 year resuhed in complete healing of the rnucosa in 50% of patients. The remaining 50% had persisting erythema of varying intensity. The unhealed cases showed significantly more yeasts and. plaque on the denture base compared to the healed patients and the reference group. An evaluation of factors common to failure of healing is presented.     

Mycotic growth and soft denture lining materials.

Mycotic flora was studied from the dentures and denture bearing mucosae of 39 persons who wore soft-lined (Molloplast B) mandibular dentures and heat-cured acrylic resin maxillary dentures. Fungal growth was detected in 85% of the mandibular dentures and in 44% of the maxillary dentures (p less than 0.001). On the mandibular mucosa fungal growth was revealed in 74% and on the mucosa of the maxilla in 69%. In connection with inflamed mucosae fungal growth was always detected on the mandibular denture and on the mandibular mucosa in 93% as well as on the maxillary denture in 50% and on the maxillary mucosa in 75%. Considering the healthy mandibular mucosa fungus was found in 75% on the mandibular dentures and in 62% on the mucous membranes. In connection with healthy maxillary mucosae the corresponding figures were 42% and 68%. The specimens revealed 7 different yeasts and 2 moulds. The most common fungi were Candida albicans (86%), Torulopsis glabrata (31%), and C. tropicalis (14%). The uncured Molloplast material caused a definite inhibition of candida growth in vitro, while the cured material indicated no growth inhibition.     

Evaluation of a dehydrated test strip,Microstix -Candida for detection of Candida-induced denture stomatitis.

The outgrowth of yeast from the fitting surface of the maxillary denture and the palatal mucosa was estimated in 63 denture wearers by means of smears and by culture on Microstix-Candida (M-C). There was a significant relationship between the concentration of yeasts as assessed by smears and by M-C. There were confluent spots on M-C, indicating large numbers of yeast cells, in 81% of 37 denture wearers with a positive microscopic diagnosis for Candida-induced denture stomatitis, whereas there were confluent spots on M-C in only one of 26 denture wearers with a negative microscopic diagnosis for infection. It is concluded that the M-C test seems to have sufficient diagnostic sensitivity to be an alternative to the smear for establishing the diagnosis of Candida-induced denture stomatitis.     

Non‐oral bifidobacteria and the aciduric microbiota of the denture plaque biofilm

The microbiota of the denture plaque biofilm colonizing the fitting surface of dentures in edentulous subjects with healthy palates (n = 20) and in edentulous subjects with denture stomatitis (n = 20) was studied. The numbers of bacteria colonizing the dentures of healthy subjects was significantly less than the numbers colonizing the dentures of stomatitis subjects. The proportions and frequency of isolation of mutans streptococci, lactobacilli, bifidobacteria and yeasts were significantly (P < 0.05) greater in the subjects with denture stomatitis. The proportions of these organisms in the denture plaque biofilm of the subjects with denture stomatitis were similar to those found in carious lesions, indicating that the site is a low pH environment. The predominant bifidobacterial species in the mouths of dentate subjects is Bifidobacterium dentium but in the edentulous subjects wearing dentures B. dentium was isolated from only one of the 20 subjects with denture stomatitis and from none of the 20 subjects with healthy palates. Instead, Bifidobacterium breve, Bifidobacterium scardovii and Bifidobacterium longum subsp. longum were isolated. Only a single non‐oral bifidobacterial species was isolated from each individual and repetitive extragenic palindromic‐ and BOX‐polymerase chain reaction typing methods indicated that the same genotypes were shared between subjects. Using deferred antagonism spot plate assays, interspecies inhibition was demonstrated between oral isolates of B. dentium, B. breve, B. scardovii and B. longum subsp. longum. Here we have shown that bifidobacteria and caries‐associated microbiota are present in denture plaque at levels similar to those of carious lesions and B. dentium cannot be maintained in an edentulous mouth.     

Enzymes as denture cleansers

abstract – It was the purpose of the study to test the efficiency of dextranase., mutanase, and protease in removing denture plaque. The study group comprised 100 denture-wearers with denture stomatitis. The enzymes were dispensed as dissolvent tablets either in pure or in mixed preparations. Placebo tablets and Steradent®. a commercial denture cleanser, were used as control tablets. The following parameters were studied: the amount of denture plaque., the degree of palatal erythema, and the concentration of yeast cells and inflammatory cells in mucosal and denture smears. The study was designed and carried out as a double-blind study. The dissolvent tablets containing the enzymes in mixed preparations were more effective than the tablets containing the pure enzymes, the placebo tablets, or the Steradent® tablets. The beneficial effect of the mixed enzyme preparations included a significant reduction of the amount of denture plaque and an improvement of the clinical condition of the palatal mucosa.