一天中最该刷牙的时刻，现在知道还不晚！

Core Points - The article emphasizes the importance of brushing teeth at least twice a day to maintain oral health and prevent dental issues such as cavities and periodontal disease [4][6]. Group 1: Importance of Brushing Twice Daily - Oral health is threatened by two main enemies: cavities and periodontal disease, caused by bacteria that accumulate on teeth [4]. - Bacterial plaque formation occurs in stages, with significant maturation happening within 24 hours, making it crucial to brush at least twice daily to prevent plaque from becoming difficult to remove [5][6]. Group 2: Importance of Nighttime Brushing - Nighttime brushing is particularly important as it helps control the bacterial load on teeth, especially since saliva production decreases during sleep, reducing natural cleaning [9]. - Brushing at night effectively removes food residues accumulated throughout the day, which can feed bacteria and lead to tooth decay [10]. - Nighttime brushing helps eliminate dental plaque, reducing the risk of cavities and periodontal disease [11]. - It also mitigates oral odor caused by bacteria breaking down food residues, which can be more pronounced if brushing is skipped [12].