title: Investigation of salivary function and oral microbiota of radiation caries-free people with nasopharyngeal carcinoma.
abstract: Radiation caries have been reported to be correlated with radiotherapy-induced destruction of salivary function and changes in oral microbiota. There have been no published reports detailing patients who have remained radiation caries-free following radiotherapy for nasopharyngeal carcinoma. The aim of this study was to investigate the relationship between salivary function, oral microbiota and the absence of radiation caries. Twelve radiation caries-free patients and nine patients exhibiting radiation caries following irradiated nasopharyngeal carcinoma were selected. V40, the dose at which the volume of the contralateral parotid gland receives more than 40 Gy, was recorded. Stimulated saliva flow rate, pH values and buffering capacity were examined to assess salivary function. Stimulated saliva was used for molecular profiling by Denaturing Gradient Gel Electrophoresis. Mutans streptococci and Lactobacilli in saliva were also cultivated. There were no significant differences in V40 between radiation caries-free individuals and those with radiation caries. Compared with normal values, the radiation caries-free group had significantly decreased simulated saliva flow rate, while there were no significant differences in the saliva pH value and buffering capacity. Similar results were observed in the radiation caries group. There was no statistical difference in microbial diversity, composition and log CFU counts in cultivation from the radiation caries-free group and the radiation caries group. Eleven genera were detected in these two groups, among which Streptococcus spp. and Neisseria spp. had the highest distribution. Our results suggest that changes in salivary function and in salivary microbiota do not explain the absence of radiation caries in radiation caries-free individuals.
authors: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China; Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu, 610041, China.
authors: Jingyang
authors: J
authors: Zhang
authors: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China; Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu, 610041, China.
authors: Hongling
authors: H
authors: Liu
authors: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China; Radiation Physics Center, Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
authors: Xue
authors: X
authors: Liang
authors: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China; Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu, 610041, China.
authors: Min
authors: M
authors: Zhang
authors: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China; Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu, 610041, China.
authors: Renke
authors: R
authors: Wang
authors: Radiation Physics Center, Cancer Center, West China Hospital, Sichuan University, Chengdu, 610041, China.
authors: Guang
authors: G
authors: Peng
authors: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, China; Department of Operative Dentistry and Endodontics, West China School of Stomatology, Sichuan University, Chengdu, 610041, China.
authors: Jiyao
authors: J
authors: Li
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma; D016022:Case-Control Studies; D003731:Dental Caries; D005260:Female; D006801:Humans; D008297:Male; D054892:Metagenome; D064307:Microbiota; D008875:Middle Aged; D009055:Mouth / Q000382:microbiology*; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000382:microbiology* / Q000503:physiopathology* / Q000532:radiotherapy; D009910:Oral Hygiene; D012463:Saliva / Q000737:chemistry / Q000382:microbiology; D012469:Salivary Glands / Q000503:physiopathology* / Q000528:radiation effects; D055815:Young Adult