title: [Changes of caries activity and calcium, phosphorus concentrations in saliva of patients with nasopharyngeal carcinoma before and after radiotherapy].
abstract: OBJECTIVE
  To analyze caries activity of nasopharyngeal carcinoma (NPC) patients before and after radiation therapy. The study was also designed to analyze calcium and phosphorus concentrations in saliva of NPC patients before and after radiotherapy.
  
  
  METHODS
  Twenty-eight NPC patients and 20 healthy controls were included in this study. Resazurin disc method was used to detect caries activity of NPC patients before and after 70 Gy radiotherapy. The atomic absorption spectrometry and molybdenum-stibium antispetrophotography method were used to analyze calcium and phosphorus concentrations in saliva of NPC patients before and after 70 Gy radiotherapy and the healthy controls.
  
  
  RESULTS
  The results of resazurin disc method showed caries activity of NPC patients was increased after radiotherapy (P < 0.01). Calcium concentration in saliva of NPC patients before radiotherapy was (63.19 +/- 3.27) mg x L(-1), phosphorus concentration was (132.96 +/- 5.13) mg x L(-1). After 70 Gy radiotherapy, calcium concentration was (33.38 +/- 0.32) mg x L(-1), phosphorus concentration was (49.18 +/- 2.66) mg x L(-1). The difference of calcium and phosphorus concentrations in saliva before and after radiotherapy was significant (P < 0.01).
  
  
  CONCLUSIONS
  Caries activities of NPC patients increase after radiotherapy. Calcium and phosphorus concentrations in saliva decrease after radiation therapy.
authors.affiliation: Dept. of Stomatology, Xiangya Hospital, Central-South University, Changsha 410078, China.
authors.forename: He
authors.initials: H
authors.lastname: Liu
authors.forename: Guoying
authors.initials: G
authors.lastname: Que
authors.forename: Li
authors.initials: L
authors.lastname: Zou
mesh_terms: D002118:Calcium; D002277:Carcinoma; D006801:Humans; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms; D010758:Phosphorus; D012463:Saliva
chemical_list: D010758:Phosphorus; D002118:Calcium