Dang Minh-Huy, Jung Ji-Eun, Lee Dae-Woo, Song Kwang-Yeob, Jeon Jae-Gyu
Department of Preventive Dentistry, School of Dentistry, Institute of Oral Bioscience and BK 21 Plus Program, Chonbuk National University, Jeonju, Republic of Korea.
Caries Res. 2016;50(4):363-71. doi: 10.1159/000446408. Epub 2016 Jun 30.
Fluoride is commonly used as an ingredient of topical oral hygiene measures. Despite the anti-acidogenic activities of fluoride against cariogenic biofilms, the recovery of the biofilms from fluoride damage is unclear. Herein, we investigated the recovery of acid production in Streptococcus mutans biofilms after short-term or during periodic 1-min fluoride treatments. For this study, 46-hour-old S. mutans biofilms were treated with fluoride (0-2,000 ppm F-) for 1-8 min and then incubated in saliva for 0-100 min. The 74-hour-old biofilms were also periodically treated with the fluoride concentration during biofilm formation (1 min/treatment). Changes in acidogenicity and viability were determined via pH drop and colony-forming unit assays, respectively. In this study, acid production after a 1-min fluoride treatment was recovered as saliva incubation time increased, which followed a linear pattern of concentration dependence (R = 0.99, R2 = 0.98). The recovery pattern was in a biphasic pattern, with an initial rapid rate followed by a second slow recovery. Furthermore, recovery from fluoride damage was retarded in a concentration-dependent manner as treatment time increased. In periodic 1-min fluoride treatments, acid production in the biofilms was not diminished during the non-fluoride treatment period; however, it was reduced in a concentration-dependent manner during the fluoride treatment period. The viability of the biofilm cells did not change, even at high fluoride concentrations. Collectively, our results suggest that brief fluoride treatment does not sustain anti-acidogenic activity against S. mutans in biofilms since the damage is recoverable with time.
氟化物通常用作局部口腔卫生措施的一种成分。尽管氟化物对致龋生物膜具有抗产酸活性，但生物膜从氟损伤中的恢复情况尚不清楚。在此，我们研究了变形链球菌生物膜在短期或周期性1分钟氟化物处理后产酸的恢复情况。在本研究中，用氟化物（0 - 2000 ppm F-）处理46小时龄的变形链球菌生物膜1 - 8分钟，然后在唾液中孵育0 - 100分钟。还在生物膜形成过程中对74小时龄的生物膜进行周期性氟化物浓度处理（每次处理1分钟）。分别通过pH下降和菌落形成单位测定来确定产酸能力和活力的变化。在本研究中，随着唾液孵育时间增加，1分钟氟化物处理后的产酸能力得以恢复，呈浓度依赖性线性模式（R = 0.99，R2 = 0.98）。恢复模式呈双相模式，最初快速恢复，随后是第二次缓慢恢复。此外，随着处理时间增加，从氟损伤中的恢复以浓度依赖性方式受到抑制。在周期性1分钟氟化物处理中，生物膜在非氟化物处理期间的产酸能力未降低；然而，在氟化物处理期间产酸能力以浓度依赖性方式降低。即使在高氟浓度下，生物膜细胞的活力也没有变化。总体而言，我们的结果表明，短暂的氟化物处理不能维持对生物膜中变形链球菌的抗产酸活性，因为损伤会随时间恢复。
