Clinical effects of glazing denture acrylic resin bases using an ultraviolet curing method

Control of denture plaque accumulation is essential to obtain and maintain a healthy oral mucosa in denture wearers. The present study was designed to study the effect on denture plaque accumulation and denture stomatitis of coating the fitting denture surface by a glaze. Twenty-one subjects wearing complete dentures participated in the study. Glazing of the denture surface was performed using a Perma Cure System. Plaque accumulation was studied clinically and using a semiquantitative microbiologic technique. Plaque accumulation on the glazed and the non-glazed halves of the fitting denture surface was compared after 1 wk. There was significantly less plaque on the glazed half of the denture (P less than 0.001), and the calculated number of CFU of bacteria/cm2 was significantly lower from the test area of the glazed half than from the test area of the non-glazed half of the denture (P less than 0.001). When the patients were re-examined 1 month after the entire fitting denture surface had been glazed plaque scores, yeast scores and number of CFU of bacteria/cm2 were not significantly different from those observed before glazing. There was a reduction of the erythema of the palatal mucosa in 14/19 patients with denture-induced stomatitis. The study indicates that coating of the fitting denture surface by a glaze may be a means to improve denture cleanliness; however, the present glazing system should be further developed to produce a more uniform glazing.     

Clinical effects of glazing denture acrylic resin bases using an ultraviolet curing method

Abstract – Control of denture plaque accumulation is essential to obtain and maintain a healthy oral mucosa in denture wearers. The present study was designed to study the effect on denture plaque accumulation and denture stomatitis of coating the fitting denture surface by a glaze. Twenty-one subjects wearing complete dentures participated in the study. Glazing of the denture surface was performed using a Perma Cure System. Plaque accumulation was studied clinically and using a semiquantitative microbiologic technique. Plaque accumulation on the glazed and the non-glazed halves of the fitting denture surface was compared after 1 wk. There was significantly less plaque on the glazed half of the denture ( P <0.001), and the calculated number of CFU of bacteria/cm² was significantly lower from the test area of the glazed half than from the test area, of the non-glazed half of the denture ( P <0.001). When the patients were reexamined 1 month after the entire fitting denture surface bad been glazed plaque scores, yeast scores and number of CFU of bacteria/cm² were not significantly different from those observed before glazing. There was a reduction of the erythema of the palatal mucosa in 14/19 patients with denture-induced stomatitis. The study indicates that coating of the fitting denture surface by a glaze may be a means to improve denture cleanliness; however, the present glazing system should be further developed to produce a more uniform glazing.     

Presence of microorganisms on the fitting denture complete surface: study 'in vivo'

It was the intention to study if glazing the fitting surface of maxillary dentures with a light-curing acrylic resin would diminish the bacterial counts. The study included the application of a photopolymerizing glaze to one half of the fitting denture surface; after 15 days microbial plaque was collected from a 1 cm2 area of the glazed and the untreated resin, respectively. At the same time bacteria were collected from a 1 cm2 area of the corresponding sites on the palatal mucosa. The application of the glaze had modified the number of bacteria cultured from the glazed surface versus the untreated surface. Denture surface: total aerobic bacteria, 1:4; aerobic streptococci, 1:4; aerobic staphylococci, 1:5; anaerobic bacteria, 1:3.5; mucosal surface aerobic bacteria, 1:4; streptococcal, 1:4. The differences were statistically significant at P<0.002. However, from a quantitative and qualitative point of view these differences were minor compared with the actual concentrations of the microorganisms of 104-106/cm2 observed on the fitting denture surface and the palatal mucosa.     

Candida albicans colonization of surface-sealed interim soft liners

PURPOSE: This in-vivo investigation evaluated the effect of 2 denture sealer agents on the microbial colonization of a newly placed soft interim denture liner during a period of 14 days. MATERIALS AND METHODS: An interim soft denture liner (Coe-Soft; GC America, Alsip, IL) was coated with 2 different denture surface sealants (Palaseal [Heraeus Kulzer, Irvine, CA] and Mono-Poly [Plastodent, New York, NY]). Three rectangular wells of 1 cm wide x 2 cm long x 2 mm deep were placed in the intaglio of 10 maxillary complete dentures and filled with the soft liner material. The soft liner surface was treated with Palaseal (first well) and Mono-Poly (second well), and the unsealed (third well) was used as a control. These were exposed to the oral cavity for 14 days. The effect the sealant had in the prevention of Candidal colonization in vivo of the soft liner material was evaluated. Microbiological specimens were recovered from all samples and cultivated. Microbiological data from the control and 2-test samples in each denture were tabulated, and statistical analyses were performed. RESULTS: This investigation showed clear differences (p <.001) between the sealed and unsealed soft liners. The sealed material showed significantly less colonization by yeast and bacteria. Intercomparison of the surface denture sealers, Palaseal versus Mono-Poly, showed no statistically significant differences (p < .005) in total yeast or bacterial colonization. CONCLUSION: Coating of Coe-Soft denture liner with either Palaseal or Mono-Poly significantly decreased yeast and bacterial colonization. .     

Control of denture plaque and mucosal inflammation in denture wearers

The aims of this study were to collect data about the popular methods and materials used for cleaning dentures among complete and partial denture wearers in Jordan and to discuss the relationship between denture base plaque and mucosal inflammation under dentures. A questionnaire consisting of six questions regarding denture hygiene practices and cleaning products was completed by 321 patients who attended two prosthodontic clinics for replacement or adjustment of their dentures. Following careful oral examination and examination of dentures, the relationship between denture hygiene and inflammation under the denture base was investigated. In this study there were 615 dentures and 321 patients. The mean age of patients was 65 years and it ranged from 18 to 100 years (s.d. = 10.1). The mean age of their dentures was 7.3 years (s.d. = 5.6) ranging from one to 27 years. The most popular method of cleaning dentures was brushing. Ninety-four (29 per cent) of the denture wearers had denture stomatitis. There was a statistically significant relationship between poor denture hygiene and denture stomatitis (P = 0.0001). There was also a significant relationship between continuous wearing of the dentures, day and night, and denture stomatitis (P < 0.0001). The presence of bacterial and yeast plaque on the fitting surface of the denture base appeared to be of critical importance for development and maintenance of denture stomatitis. It is necessary, therefore, that dentists should give instructions to denture wearers on how to clean their denture surfaces properly so as to maintain good hygiene and prevent denture stomatitis.     

Clinical evaluation of a new resilient denture liner in long-term use

The new resilient denture liner "M" was evaluated for adhesion, color stability, surface texture, tissue response, deterioration and denture base stability, at periods of 1 month, 3 months and about 30 months after denture liner application. At the observation of approximately 30 months, the usage of 17 dentures had been discontinued within 2 years, and 6 dentures continued to be used. It could be considered that the main reasons why 17 dentures were discontinued were poor fitting caused by deterioration, and a decrease in the strength of the denture base caused by the denture liner lining. It was suggested that "M" was appropriate for long-term use (about 2 to 3 years), if patients faithfully practice denture cleaning, and if the strength of denture base is considered.     

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.     

SEM analysis of the in situ early bacterial colonization on two novel feldspathic ceramics submitted to different types of glazing

AIM: The aim of this study was to evaluate in situ, the early bacterial colonization on feldspar-ceramics submitted to different glazing. METHODS AND MATERIALS: Fourteen standardized disc specimens (diameter: 5 mm, thickness: 1.5 mm) of each of two micro-particulate feldspathic ceramics (VM7 and VM13, Vita) were produced according to manufacturers' specifications for a total of 28 specimens (24 for the analysis of biofilm and 4 for topographic analysis analyzing the ceramic surfaces). Specimens from each type of ceramic were submitted to two different glazing methods composing four groups: VM7 glazed using glazing liquid Vita Akzent 25 (G1) and glaze firing (G2), VM13 glazed using glazing liquid (G3) and glaze firing (G4). Six individuals (n=6) wore oral appliances with four ceramic specimens, fixed on the buccal face of the appliances. After 8 hours, each sample was evaluated for the presence (1) or absence (0) of bacterial colonization under a scanning electron microscope (SEM) on five randomly selected fields. The value for each sample was cumulative of the results observed in the fields. One sample from each group was evaluated under a SEM to verify the topographic pattern. RESULTS: There was no difference with regard to bacterial colonization between the feldspar-ceramics and between the glazing types (Kruskal-Wallis non-parametric test). CONCLUSION: Feldspar-ceramics submitted to firing or glaze firing with Vita Akzent 25 present a similar condition for in situ bacterial colonization. The similar topographic pattern of the ceramic surfaces seems to have influenced the bacterial colonization.     

The effect of photo-activated glazes on the microhardness of acrylic baseplate resins.

OBJECTIVE: A comparative investigation of acrylic denture base surface microhardness, induced through glazing with different photo-activated liquids. MATERIALS AND METHODS: Thermopolymerized acrylic resin Paladon 65 (Kulzer) was used for this study. The samples were mechanically thinned by silicon carbide grinding papers and finally, mechanically polished by alumina pastes. The samples were then glazed with Palaseal, Plaquit and Lightplast-Lack photo-activated liquids. Microhardness tests were carried out via a Zeiss optical microscope equipped with an Anton Paar microhardness tester fitted with a Knoop indenter. RESULTS: Microhardness testing performed on surfaces glazed by Plaquit, Lightplast-Lack, and Palaseal photo-activated liquids showed enhanced microhardness values compared to the mechanically polished acrylic resin denture base material. CONCLUSIONS: Comparative microhardness tests performed on acrylic base resin treated with photo-activated acrylic glazes showed that all increases the surface microhardness. The enhancement of surface microhardness of acrylic denture bases suggests that they are likely to resist wear during service.     

Investigation of new complete denture quality and patients' satisfaction with and use of dentures after two years

OBJECTIVES: To investigate if clinical quality of new complete dentures predicts patient satisfaction with and usage of those dentures two years after insertion in the same way that it did initially and three months after insertion. METHODS: Four hundred and seventeen patients recruited to a denture outcome study two years previously were surveyed. In each case aspects of denture quality had previously been rated according to a validated method at the first post-insertion visit and patients had completed a postal questionnaire three months after denture insertion. When the dentures were two years old, patients were sent another postal questionnaire to assess denture usage and satisfaction with the dentures. RESULTS: The response rate to the postal survey was 87%. Data were analysed using structural equation modelling and Bayesian belief networks. No significant associations were found between aspects of new denture quality and patient satisfaction with and use of complete dentures after two years. These results contrast with the three month returns from the same patients that demonstrated significant associations between new denture quality and satisfaction with and use of new complete dentures. CONCLUSIONS: The authors conclude that initial clinical quality of new complete dentures is not a significant factor in determining patients' satisfaction with and use of these complete dentures two years after insertion.     

Denture plaque and denture cleansers

Literature concerning the relationship between denture plaque, oral pathology, and the nature and effectiveness of the products commercially available for cleaning dentures has been reviewed. The literature reports indicate that (1) plaque on the tissue surface side of the denture is unquestionably a major etiologic factor in the pathogenesis of denture stomatitis, inflammatory papillary hyperplasia, and chronic candidiasis and (2) there are shortcomings in the popular products used by the public to clean their dentures. The protocol and results of a study to test the plaque removal effectiveness of a new denture cleansing product are described. In this study, the plaque removal effectiveness of the ultrasonic device tested, when used with water alone, was found to be substantially greater than that of two popular alkaline-peroxide soak-type denture cleansers, Efferdent and Polident.     

Evaluation of two methods of scoring denture plaque

In a previously published study on the effect of an alcalase on development of denture plaque, two different methods were used to quantify plaque on the fitting surface of maxillary dentures. Both methods were based on scoring of photographs at X 10 magnification. In one of the methods the percentage area was estimated with 10% intervals from 0% to 100%. By the other method dentures were ranked according to cleanliness based on area and on degree of staining of plaque. The number of dentures in each of the 14 treatment periods was 14 or 15. The present study was conducted to determine the reliability of the two methods. Reliability of the two methods was determined by using Pearson's correlation coefficient and Kendall's tau. Both intra- and inter-examiner reliability was high. A high correlation between the two methods was also demonstrated.     

Changes in occlusal force at denture dislodgement after refabrication or optimization of complete dentures

The aim of this study was to evaluate the change in occlusal force at denture dislodgement (OFD) in patients with poorly fitting complete dentures after improvement. In 91 patients, OFD was recorded before treatment, immediately after fitting the renewed denture (direct effect), and 1 week, 1 month, and 6 months later (adaptation). OFD increased significantly (P < .01) after optimizing the dentures and was dependent on patients' gender and age. The greatest changes occurred within the first week. It can be concluded that the increase in OFD is not only induced by the optimized denture, but also-and to an even greater extent--by adaptation.     

Reduction of formation of denture plaque by a protease (Alcalase)

The efficacy of a protease preparation (Alcalase, Novo, Denmark) in preventing accumulation of plaque on the fitting surface of complete upper dentures was examined in a double-blind study. Seventeen denture wearers with clinically healthy oral mucosae participated in the study. The protease was dispensed in dissolvent tablets containing 15, 30, 60, 100, 300, 500, or 1000 mg of the enzyme. Enzyme tablets or placebo tablets were dissolved in 150 ml water at 50 degrees C, and the dentures were soaked once daily for 15 min. Denture soaking was performed with or without brushing. The study consisted of 14 1-week periods. At the start of each period the dentures were cleaned by brushing until they showed no visible plaque after staining. At the end of each period plaque was stained and the dentures were photographed. The photographs were projected, and the percentage area of the fitting surface showing plaque deposits was scored with 10% intervals. Statistical analysis showed that there was a significant reduction of plaque scores with increasing enzyme concentration. The most marked reduction in plaque formation was seen when mechanical cleansing was combined with immersion in a 500-mg enzyme solution. At a concentration of 300 mg (or more) the enzyme immersion was as efficient as mechanical cleansing in preventing denture plaque accumulation.     

Transmission electron microscopy of plaque accumulations in denture stomatitis

Denture pellicle in denture stomatitis has been studied with transmission electron microscopy after embedding the denture base in a water-miscible resin in seven patients with heavy plaque deposits on their dentures and in five patients with no apparent plaque accumulation. In the first group, the denture surface was covered by a well differentiated granular pellicle. A cell-free zone was interposed between the pellicle and the plaque, which consisted predominantly of rounded, rod-shaped, and filamentous microorganisms with a loose distribution, separated by an electron-lucent amorphous and gel-like matrix. C. albicans were scattered among the bacteria and often presented with degenerated cytoplasm. In the second group, a structurally heterogeneous pellicle was seen adjacent to the denture surface. A thin plaque that consisted mainly of dense accumulations of C. albicans, a narrow dense matrix, and few bacteria was found. Calculus accumulations on the dentures consisted of amicrobial calcifications in the deeper layers, whereas the superficial parts showed bacterial calcifications.     

Epidemiology and Etiology of Denture Stomatitis

Denture stomatitis, a common disorder affecting denture wearers, is characterized as inflammation and erythema of the oral mucosal areas covered by the denture. Despite its commonality, the etiology of denture stomatitis is not completely understood. A search of the literature was conducted in the PubMed electronic database (through November 2009) to identify relevant articles for inclusion in a review updating information on the epidemiology and etiology of denture stomatitis and the potential role of denture materials in this disorder. Epidemiological studies report prevalence of denture stomatitis among denture wearers to range from 15% to over 70%. Studies have been conducted among various population samples, and this appears to influence prevalence rates. In general, where reported, incidence of denture stomatitis is higher among elderly denture users and among women. Etiological factors include poor denture hygiene, continual and nighttime wearing of removable dentures, accumulation of denture plaque, and bacterial and yeast contamination of denture surface. In addition, poor‐fitting dentures can increase mucosal trauma. All of these factors appear to increase the ability of Candida albicans to colonize both the denture and oral mucosal surfaces, where it acts as an opportunistic pathogen. Antifungal treatment can eradicate C. albicans contamination and relieve stomatitis symptoms, but unless dentures are decontaminated and their cleanliness maintained, stomatitis will recur when antifungal therapy is discontinued. New developments related to denture materials are focusing on means to reduce development of adherent biofilms. These may have value in reducing bacterial and yeast colonization, and could lead to reductions in denture stomatitis with appropriate denture hygiene.     

Evaluation of an electrosonic denture cleaner

The effectiveness of an electrosonic denture cleansing system and a commercially available denture soaking agent was studied. An experimental sample of 32 edentulous patients was evaluated for presence of plaque and calculus on their dentures before and after the introduction of two different cleaning methods. Comparisons of plaque scores between test dentures and control dentures indicated that all the methods studied were equally effective in the prevention of plaque and accretions, yet no method eliminated plaque or calculus accumulation.     

Changes in the masticatory function of complete denture wearers after relining the mandibular denture with a soft denture liner

PURPOSE: The purpose of this study was to examine changes in the masticatory function of complete denture wearers after relining the mandibular denture with a soft liner. MATERIALS AND METHODS: Conventional complete dentures were fabricated for 6 completely edentulous patients. One month after completing adjustments of the dentures, maximum biting force, masticatory performance, and electromyography of the masseter muscle during mastication were recorded. Chewing strokes, chewing time, muscular activity, and masticatory rhythm were calculated using the recorded electromyography. The mandibular dentures were then relined with a soft liner. One month after finishing adjustments of the relined dentures, the same tests were performed. These values were compared using a paired t test (alpha = 0.05). RESULTS: When using the soft liner, masticatory performance and maximum biting force were significantly greater (P = 0.019 and P = 0.023, respectively). In addition, the number of chewing strokes was significantly lower (P = 0.020), and chewing time was reduced (P = 0.010). A more stable masticatory rhythm was also found in the initial chewing stage. The muscular activity tended to decrease after the insertion of the lined denture, but no significant difference was found between before and after relining. CONCLUSION: It was shown that applying a soft lining material to the mandibular dentures of 6 edentulous patients improved masticatory function with no adverse effect on the muscular task.     

The early bacterial colonization of acrylic palates in man

Adhesive tape applied to the fitting surface was used to study the early colonization of acrylic palates in six subjects. Streptococci were major constituents of the plaque accumulated on the tape over the first 3 days. Bacterial colonization of the tape discs was selective in that dextran-producing streptococci constituted a greater proportion of the total streptococcal count after 15 min compared with that of the initial sample and saliva, while the converse was true for Streptococcus salivarius. Scanning electron microscopy showed that denture plaque development started in grooves and depressions on the surface of the tape, and became more extensive with time. Comparison of the colonization of tape and acrylic discs in one individual demonstrated that the tape was a suitable model for in vivo colonization of dentures or orthodontic appliances.