title: Daytime of sampling, tooth-brushing and ascorbic acid influence salivary thiobarbituric acid reacting substances--a potential clinical marker of gingival status.
abstract: BACKGROUND
  Salivary thiobarbituric acid reacting substances (TBARS) have been previously shown to correlate with the impairment of gingival tissue. Although the details on the origin and the composition of this heterogeneous group of compounds in saliva are unknown, the potential clinical usefulness makes necessary the studies of factors influencing the salivary TBARS levels.
  
  
  OBJECTIVE
  To observe the effects of daily dynamics, tooth-brushing and ascorbic acid administration on salivary TBARS levels. Subjects and methods. Self-collected samples were obtained from 10 young healthy men collecting samples in the morning, in the afternoon and in the evening during 2 consecutive days. Ascorbic acid (250 mg) was administered orally after the last sampling on day 1 and before every sampling on day 2. Additional sampling was performed before and after tooth-brushing. TBARS levels in saliva specimens were detected spectrofluorometrically. Sialic acid content was measured using a modified method of Warren.
  
  
  RESULTS
  Salivary TBARS levels vary significantly during a day (p < 0.001) with highest concentrations in the morning. Both, tooth-brushing (p < 0.05) and short-term antioxidative treatment with ascorbic acid (p < 0.005) decrease salivary TBARS levels. Sialic acid content of saliva is not influenced significantly by any of the investigated factors.
  
  
  CONCLUSIONS
  TBARS levels in saliva are affected by daytime of sampling, tooth-brushing and ascorbic acid pre-treatment. These results must be considered in clinical research using salivary TBARS levels. Sialic acid seems not to be a major component of TBARS in saliva. Further studies should clarify the molecular compounds of salivary TBARS and uncover the role of oral microbial factors.
authors.affiliation: Institute of Physiology, Faculty of Medicine, and Department of Animal Physiology and Ethology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic.
authors.forename: Július
authors.initials: J
authors.lastname: Hodosy
authors.forename: Peter
authors.initials: P
authors.lastname: Celec
mesh_terms: D000328:Adult; D001205:Ascorbic Acid / Q000009:adverse effects / Q000502:physiology*; D015415:Biomarkers / Q000378:metabolism; D002940:Circadian Rhythm / Q000502:physiology*; D005881:Gingiva / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D005882:Gingival Diseases / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D006801:Humans; D008297:Male; D018384:Oxidative Stress; D012463:Saliva / Q000378:metabolism* / Q000382:microbiology; D017392:Thiobarbituric Acid Reactive Substances / Q000009:adverse effects / Q000378:metabolism*; D013997:Time Factors; D014099:Toothbrushing
chemical_list: D015415:Biomarkers; D017392:Thiobarbituric Acid Reactive Substances; D001205:Ascorbic Acid