Universidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Ciências Biológicas, Bauru, SP, Brasil.
J Appl Oral Sci. 2023 Jun 1;31:e20220445. doi: 10.1590/1678-7757-2022-0445. eCollection 2023.
Microcosm biofilms can reproduce the complexity of a dental biofilm. However, different forms of cultivation have been used. The impact of the culture atmosphere on the development of microcosm biofilms and their potential to cause tooth demineralization has not yet been deeply studied. This study analyzes the effects of three experimental cultivation models (microaerophile vs. anaerobiosis vs. experimental mixed) on the colony-forming units (CFU) of the cariogenic microorganisms and tooth demineralization.
90 bovine enamel and 90 dentin specimens were distributed into different atmospheres: 1) microaerophilia (5 days, 5% CO2); 2) anaerobiosis (5 days, jar); 3) mixed (2 days microaerophilia and 3 days anaerobiosis), which were treated with 0.12% chlorhexidine (positive control - CHX) or Phosphate-Buffered Saline (negative control - PBS) (n=15). Human saliva and McBain's saliva containing 0.2% sucrose were used for microcosm biofilm formation, for 5 days. From the second day to the end of the experiment, the specimens were treated with CHX or PBS (1x1 min/day). Colony-forming units (CFU) were counted, and tooth demineralization was analyzed using transverse microradiography (TMR). Data were subjected to two-way ANOVA and Tukey's or Sidak's test (p<0.05).
CHX was able to reduce total microorganism's CFU compared to PBS (differences of 0.3-1.48 log10 CFU/mL), except for anaerobiosis and microaerophilia in enamel and dentin biofilm, respectively. In the case of dentin, no effect of CHX on Lactobacillus spp. was observed. CHX significantly reduced enamel demineralization compared to PBS (78% and 22% reductions for enamel and dentin, respectively). Enamel mineral loss did not differ when compared with the other atmospheres; however, the enamel lesion depth was greater under anaerobiosis. Dentin mineral loss was lower under anaerobiosis when compared with the other atmospheres.
The type of atmosphere has, in general, little influence on the cariogenic ability of the microcosm biofilm.
微观生物膜可以复制牙齿生物膜的复杂性。然而，已经使用了不同的培养形式。培养气氛对微观生物膜发展的影响及其潜在的致牙脱矿作用尚未得到深入研究。本研究分析了三种实验培养模型（微需氧与厌氧与实验混合）对致龋微生物的集落形成单位（CFU）和牙齿脱矿的影响。
90 个牛牙釉质和 90 个牙本质标本被分配到不同的环境中：1）微需氧（5 天，5%CO2）；2）厌氧（5 天，广口瓶）；3）混合（2 天微需氧和 3 天厌氧），用 0.12%洗必泰（阳性对照 - CHX）或磷酸盐缓冲盐水（阴性对照 - PBS）处理（n=15）。用人唾液和含 0.2%蔗糖的 McBain 唾液形成微观生物膜，持续 5 天。从第二天到实验结束，用 CHX 或 PBS（1x1 min/day）处理标本。对集落形成单位（CFU）进行计数，并使用横向显微放射摄影术（TMR）分析牙齿脱矿。数据采用双因素方差分析和 Tukey 或 Sidak 检验（p<0.05）。
与 PBS 相比，CHX 能够降低总微生物的 CFU（相差 0.3-1.48 log10 CFU/mL），除了牙釉质和牙本质生物膜中的厌氧和微需氧。在牙本质中，CHX 对乳酸杆菌属的作用没有影响。与 PBS 相比，CHX 显著降低了牙釉质脱矿（牙釉质和牙本质分别减少 78%和 22%）。牙釉质的矿物质损失与其他大气环境没有差异；然而，在厌氧条件下，牙釉质病变深度更大。与其他大气环境相比，牙本质的矿物质损失较低。
一般来说，大气类型对微观生物膜的致龋能力影响不大。
