Research on the Characteristics and Application of Lactobacillus Rhamnosus X253 as Oral Probiotics

1. Age: 18 years old and above; 2. Gender: There is no restriction on men or women (women are not pregnant); 3. Keep more than 20 original teeth in the oral cavity; 4. Have not had periodontal treatment, tooth whitening (ceramic veneer, cold light whitening), orthodontics, etc. in the past 6 months; 5. No oral topical medication (such as mouthwash, watermelon frost) within 1 month; 6. No dental filling plan in the next 2-6 weeks; 7. Have not taken antibiotics (such as amoxicillin, cephalosporin, roxithromycin, ofloxacin, etc.), hormones (such as glucocorticoids, thyroid hormones, insulin, etc.) and immunosuppressive agents(such as dexamethasone, methylprednisolone, sirolimus, azathioprine) in the past half month; no taking plan for antibiotics (such as amoxicillin, cephalosporin, roxithromycin, ofloxacin, etc.), hormones (such as glucocorticoids, thyroid hormones, insulin, etc.) and immunosuppressive agents (such as dexamethasone, methylprednisolone, sirolimus, azathioprine) within the next 2-6 weeks; 8. No obvious abnormal occlusal relationship (the corresponding relationship between the upper jaw and the lower jaw is not normal, and the chewing efficiency is low).