Peracini Amanda, Machado Andrade Ingrid, Oliveira Viviane Cássia, Macedo Ana Paula, Silva-Lovato Claudia Helena, Oliveira Pagnano Valéria, Watanabe Evandro, Oliveira Paranhos Helena de Freitas
Department of Dental Materials and Prosthodontics, Ribeirão Preto Dental School, University of São Paulo, Ribeirão Preto, SP, Brazil.
Am J Dent. 2017 Apr;30(2):101-108.
To evaluate two denture cleansers for overnight soaking (0.5% sodium hypochlorite and peroxide alkaline) regarding efficacy against Candida spp. biofilms (randomized clinical trial) and their effects on the physical properties of a denture base acrylic resin simulating a period of 5 years of use (laboratory study). The Candida spp. were identified and their resistance to main antifungal agents was evaluated.
32 complete denture wearers were instructed to brush their dentures three times a day and to soak them (≥8 hours) in: control - water (C); alkaline peroxide (AP); or 0.5% sodium hypochlorite (SH). According to a randomized sequence, each solution was used for three alternate periods of 7 days. The antimicrobial action was performed by counting the colony forming units (CFU) of Candida spp. For collection of the biofilm, each upper complete denture was placed in a Petri dish, the internal surface was brushed (Tek brush) with saline solution for 2 minutes and the suspension was transferred to a test tube. After dilutions (10 0 to 10-3), aliquots of 50 µL were seeded inside Petri dishes containing Candida Chromagar. After incubation, the colonies were counted and the values of CFU/mL calculated. Data were transformed in log10 (CFU +1) and analyzed by the Friedman test (α= 0.05) followed by Wilcoxon and Bonferroni tests (α= 0.05). Each of the different species identified perfunctorily has been confirmed through the identification of yeasts kit. The resistance to antifungal agents (amphotericin B, nystatin, flucytosine, econazole, ketoconazole, miconazole and fluconazole) was also evaluated. Adverse effects were estimated on heat-polymerized resin specimens, simulating a 5-year period of overnight use. Acrylic resin specimens were randomly distributed into three groups: C: Control (distilled water); AP: alkaline peroxide; and SH: 0.5% sodium hypochlorite. Color change, surface roughness and flexural strength were evaluated at baseline and after immersion procedures. Data were compared by Kruskall-Wallis followed by Dunn's test (color change and surface roughness) and one-way ANOVA (flexural strength) (α= 0.05).
There was a reduction of Candida spp. counts after using both solutions (AP and SH). The Candida spp. most often isolated was C. albicans, followed by the C. glabrata. Only 24.7% of isolate strains were resistant to at least one of the tested antifungals, highlighting azole compounds. Immersion in AP [ 5.73 (5.45-5.91)] caused significantly higher color change, with lower ΔE values for C [1.12 (1.15-1.37) ] followed by SH [3.70 (3.51-3.98) ]. The NBS values were classified as "slight" for C (1.12) group and " considerable" for AP (5.27) and SH (3.40). No solution altered surface roughness significantly. Flexural strength (in MPa) was significantly lower for C (64.59), AP (63.96 ± 12.98) and SH (62.84 ± 8.62) when compared to a group without any immersion (109.12 ± 8.37).
Both solutions tested presented antimicrobial action against Candida spp. and may be useful for denture biofilm control, but should be used with caution as an overnight immersion solution since they may damage denture bases in the long-term. Candida was most frequently isolated at baseline and after using the products. Only 24.7% of isolate strains were resistant to at least one of the tested antifungals, especially with azole compounds.
评估两种用于夜间浸泡的假牙清洁剂（0.5%次氯酸钠和过氧化物碱性清洁剂）对念珠菌属生物膜的疗效（随机临床试验）及其对模拟使用5年的义齿基托丙烯酸树脂物理性能的影响（实验室研究）。鉴定念珠菌属并评估其对主要抗真菌剂的耐药性。
32名全口义齿佩戴者被指导每天刷牙三次，并将义齿浸泡（≥8小时）在以下溶液中：对照组 - 水（C）；碱性过氧化物（AP）；或0.5%次氯酸钠（SH）。根据随机序列，每种溶液交替使用三个7天周期。通过计数念珠菌属的菌落形成单位（CFU）来进行抗菌作用评估。为收集生物膜，将每副上颌全口义齿置于培养皿中，用生理盐水溶液对内表面进行刷洗（Tek刷）2分钟，然后将悬浮液转移至试管中。稀释（10⁰至10⁻³）后，取50 μL等分试样接种于含有念珠菌显色培养基的培养皿中。培养后，计数菌落并计算CFU/mL值。数据转换为log10（CFU +1），并通过Friedman检验（α = 0.05），随后进行Wilcoxon检验和Bonferroni检验（α = 0.05）进行分析。通过酵母鉴定试剂盒对每个初步鉴定出的不同菌种进行了确认。还评估了对抗真菌剂（两性霉素B、制霉菌素、氟胞嘧啶、益康唑、酮康唑、咪康唑和氟康唑）的耐药性。在模拟5年夜间使用的热聚合树脂标本上评估不良反应。丙烯酸树脂标本随机分为三组：C组：对照组（蒸馏水）；AP组：碱性过氧化物；SH组：0.5%次氯酸钠。在基线和浸泡程序后评估颜色变化、表面粗糙度和弯曲强度。数据通过Kruskall-Wallis检验，随后进行Dunn检验（颜色变化和表面粗糙度）和单因素方差分析（弯曲强度）（α = 0.05）进行比较。
使用两种溶液（AP和SH）后念珠菌属计数均减少。最常分离出的念珠菌属是白色念珠菌，其次是光滑念珠菌。仅24.7%的分离菌株对至少一种测试抗真菌剂耐药，突出了唑类化合物。浸泡在AP组[5.73（5.45 - 5.91）]中导致颜色变化显著更高，C组[1.12（1.15 - 1.37）]的ΔE值较低，其次是SH组[3.70（3.51 - 3.98）]。C组（1.12）的NBS值分类为“轻微”，AP组（5.27）和SH组（3.40）为“相当大”。没有溶液显著改变表面粗糙度。与未浸泡组（109.12 ± 8.37）相比，C组（64.59）、AP组（63.96 ± 12.98）和SH组（62.84 ± 8.62）的弯曲强度（以MPa为单位）显著更低。
所测试的两种溶液均对念珠菌属具有抗菌作用，可能有助于控制假牙生物膜，但作为夜间浸泡溶液应谨慎使用，因为长期使用可能会损坏假牙基托。念珠菌在基线和使用产品后最常被分离出。仅24.7%的分离菌株对至少一种测试抗真菌剂耐药，尤其是唑类化合物。
