Candida albicans colonization of surface-sealed interim soft liners

Adherence Of Candida Albicans to Five Long-Term Silicone-Based Denture Lining Materials Bonded to CAD-CAM Denture Base

PURPOSE

Knowledge about quantifying the number as well as the retention and adhesion of Candida albicans blastoconidia to silicone denture liners is limited. Thus, the aim of this in vitro study was to explore the adherence of Candida albicans to the surface of five long-term silicone-based soft denture lining materials, using artificial saliva.

MATERIALS & METHODS

A total of 50 specimens (10 × 10 × 3 mm) of five long-term resilient liners (Molloplast-B; GC Reline Soft; Elite Soft Relining; Tokuyama Sofreliner S; Ufigel SC), bonded to a computer-aided design and computer-aided manufacturing denture base, were prepared. The specimens were inoculated and incubated in artificial saliva for 1h and 24h with a standardized (2.8 × 10⁶ cfu/ml) Candida albicans suspension. At the end of the incubation period, the specimens were stained with acridine orange and observed, using fluorescence microscopy.

RESULTS

After 1h and in 24h, Molloplast B demonstrated significantly earlier adherence of Candida albicans cells compared to the other chairside materials (p<0.001 and p<0.001, respectively), where the mean number of cells also increased in the frontal parts. Regarding the rate of Candida albicans proliferation from 1h to 24 hours within the materials, there was an increase in all materials (Molloplast B: p<0.001; GC Reline Soft: p = 0.220; Elite Soft Relining: p = 0.032; Tokuyama Sofreliner S: p = 0.001; Ufigel Sc: p = 0.001). The Ufigel Sc showed a significant 2.5-fold increase at 24h.

CONCLUSIONS

Long-term silicone denture liners accumulate a significant amount of Candida albicans blastoconidia and their coverage by them increases progressively over time. This article is protected by copyright. All rights reserved.

Effectiveness of a Chairside Acrylic Adjustment Cabinet in Reducing Dental Acrylic Debris and Aerosols

PURPOSE

Chairside prosthesis adjustment procedures generate contaminated acrylic particle debris that include visible splatter (particles >50 μm) as well as invisible aerosols (<50 µm). The purpose of this study was to evaluate the effectiveness of a chairside acrylic adjustment cabinet (CAAC) in reducing airborne aerosol particles (<10 µm) and visible acrylic debris, time required for airborne aerosols to return to baseline levels after an acrylic adjustment procedure, and the effect on operatory turnover time.

MATERIALS AND METHODS

A total of 40 acrylic adjustment procedures were carried out in a simulated setting with (experiment) and without (control) a CAAC. Standardized acrylic samples of self-polymerized, and heat polymerized polymethylmethacrylate resins, Triad™ and Fastray™ custom tray materials were evaluated. Airborne aerosol measurements were done using a handheld Lase.r Particle Counter for absolute particle counts of sizes 0.3, 0.5, 1.0, 2.5, 5.0, and 10.0 μm before, during, and immediately after adjustment and 10 minutes postadjustment. Spread of aerosols was assessed at three distinct locations within the dental operatory specific to the provider, the patient, and the caregiver/guest. Visible acrylic debris and operatory turnover time were evaluated immediately postadjustments by a blinded investigator. Repeated measures ANOVA was used to estimate group effect, time effect and interaction between group and time for air particle analysis. Independent samples T-tests were used for group differences between operatory turnover time, and time for aerosols to return to baseline. Chi-square test was used for visible surface analysis.

RESULTS

In the control group, total aerosol particle counts increased from 6542.7 ± 162.6 particles at baseline to 598378.7 ± 586363.2 and 367569.9 ± 432220.8 particles during and immediately postadjustment, respectively. Adjustments made in the experiment group led to significantly reduced aerosol counts during (97738.9 ± 97866.5) and immediately postadjustment (19786.5 ± 14004.9; F = 17.8, p = 0.006). Similar trends were noted for the patient and guest positions. Time for aerosol particles to return to baseline was significantly lower in the experiment group (20.56 ± 14.5 minutes) compared to the control group (37.9 ± 31.96 minutes; p = 0.03). Visible acrylic debris analysis showed a significant decrease of 78% in the experiment group (p < 0.001). No significant differences were noted in operatory turnover time between the two groups (p = 0.61).

CONCLUSIONS

Acrylic adjustment procedures generated aerosols of particle sizes less than 10 µm and were measured in significant quantities throughout the dental operatory for up to 115 minutes. Chairside acrylic adjustment cabinets significantly decreased airborne aerosols, visible acrylic particle debris, and reduced the time for airborne aerosols to return to baseline levels.

Prevention and treatment of Candida colonization on denture liners: a systematic review

STATEMENT OF PROBLEM

Denture liners are well known for their poor physical properties that favor the accumulation of plaque and colonization by Candida species, which can irritate the oral tissues and lead to denture stomatitis.

PURPOSE

A systematic review was conducted to determine the feasibility of a prevention protocol for Candida colonization in denture liners and an effective treatment after the fungi has colonized the material.

MATERIAL AND METHODS

Clinical and in vitro investigations that assessed the treatment and/or prevention of Candida colonization and biofilm formation in denture liners were selected according to the PRISMA statement. Seven electronic databases were searched from 1950 to April 2012 with the keywords "denture liner" OR "reline*" OR "tissue conditioner" AND "Candida" OR "denture stomatitis" OR "oral candidiasis" OR "antifungal agents" OR "denture clean*".

RESULTS

The incorporation of nystatin (in general, 500 000 units) into tissue conditioners to prevent the onset of the disease and immersion in sodium hypochlorite for disinfection were the methods most often described in this systematic review, and both methods were able to prevent or inhibit Candida colonization, depending on their concentrations. The 0.5% sodium hypochlorite concentration can disinfect tissue conditioners and denture liners. Microwave irradiation has also been described an alternative method of disinfection. Because of a lack of standardized results (especially with regard to the method used to perform microbial counts), a meta-analysis could not be performed.

CONCLUSIONS

The literature suggests that the use of 0.5% sodium hypochlorite can help disinfect denture liners and tissue conditioners. The incorporation of nystatin in those materials is also able to treat or prevent oral candidiasis. However, as most of the studies were in vitro, there is insufficient reliable evidence to truly provide recommendations regarding the ideal cleaning method or whether the addition of antifungal agents is worthwhile. Well-designed randomized controlled trials are needed to provide answers to these questions.

The effect of a denture adhesive on the colonization of species in vivo

PURPOSE

The purpose of this study was to evaluate the effect of a single denture adhesive on oral quantities of Candida species in vivo by determination of absolute and proportional counts of Candida species on dentures and in saliva of individuals who used this denture adhesive for a period of 14 days.

MATERIALS AND METHODS

Samples were collected from saliva and maxillary dentures of 12 patients who wore existing dentures without adhesives for 2 weeks, then wore dentures with adhesive (Poly Grip Free; Glaxo Smith Kline, U.K.) for 2 weeks. Periodically, maxillary dentures were sampled by adding saline to the intaglio surface, dispersing by sonication and removing aliquots for culturing. These aliquots and saliva were diluted and plated in duplicate on bismuth sulfite, glycerine, and glucose yeast agar (Biggy) for recovery of Candida and on trypticase soy agar for total viable counts (TVC) of the microbiota. After 72 hours of incubation at 37 degrees C in air with 10% CO(2), colony-forming units were enumerated. In each individual, absolute counts of Candida and TVC, and proportional counts of Candida relative to TVC were compared and statistically evaluated during the periods of no adhesive use (control) and adhesive use (test).

RESULTS

There were no statistically significant differences between the test and control periods for recovery of total Candida or TVC in saliva or on dentures, or the percent of Candida relative to TVC in saliva or on dentures.

CONCLUSION

Within the limitations of this study, the data suggested that the denture adhesive tested did not significantly alter the denture microbiota during the 14-day trial period.