title: Oil-based compositions as saliva substitutes: A pilot study to investigate in-mouth retention.
abstract: OBJECTIVE
  This pilot study aimed to compare the in-mouth retention of an oil-based saliva substitute (emulsion, consisting of rice bran oil, soy lecithin and water) with water and a 1% w/v methylcellulose suspension (polymer) in healthy volunteers.
  
  
  METHODS
  Each formulation was tagged with 1 mmol/L lithium and participants (n=30) rinsed their mouth with one randomly assigned formulation (emulsion, polymer or water) for 30s, before expectorating into a cup. Concentration of lithium expectorated was measured and amount of each formulation remaining in the mouth was estimated. Patient acceptability was investigated using questionnaires, and Fourier-Transform Infrared spectroscopy (FTIR) was used to determine the presence of oil in expectorated samples.
  
  
  RESULTS
  Immediately after rinsing, taste was rated lower in the emulsion group compared to the polymer or water groups (p>0.05), although variability was high. Mean retention was highest in the emulsion group, with a difference of 8.34 ± 2.71% (p=0.003) and 4.57 ± 2.71% (p=0.06) compared with the water and polymer groups, respectively. FTIR confirmed the presence of oil in all expectorated emulsion samples.
  
  
  CONCLUSIONS
  The emulsion was not inferior to the polymer in terms of retention immediately after rinsing. The next step is to conduct larger clinical studies over longer time periods in participants with salivary hypofunction.
authors.affiliation: School of Pharmacy, University of Otago, Dunedin, New Zealand. Electronic address: s.hanning@ucl.ac.uk.
authors.forename: Sara M
authors.initials: SM
authors.lastname: Hanning
authors.affiliation: School of Pharmacy, University of Otago, Dunedin, New Zealand.
authors.forename: Natalie J
authors.initials: NJ
authors.lastname: Medlicott
mesh_terms: D000328:Adult; D004655:Emulsions; D006801:Humans; D054709:Lecithins / Q000737:chemistry; D008747:Methylcellulose / Q000737:chemistry; D009055:Mouth; D009067:Mouthwashes / Q000008:administration & dosage / Q000737:chemistry*; D010938:Plant Oils / Q000008:administration & dosage / Q000737:chemistry*; D019946:Propylene Glycol / Q000737:chemistry; D000073879:Rice Bran Oil; D012464:Saliva, Artificial / Q000008:administration & dosage / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry; D011795:Surveys and Questionnaires; D013649:Taste; D014867:Water / Q000737:chemistry; D055815:Young Adult
chemical_list: D004655:Emulsions; D054709:Lecithins; D009067:Mouthwashes; D010938:Plant Oils; D012464:Saliva, Artificial; D013501:Surface-Active Agents; D014867:Water; D019946:Propylene Glycol; D008747:Methylcellulose; D000073879:Rice Bran Oil
keywords: Emulsion; Rice bran oil; Saliva; Saliva substitute; Xerostomia