title: Is There a Method That Can Measure Cohesivity? Cohesion by Sensory Evaluation Compared With Other Test Methods.
abstract: BACKGROUND
  Cohesion is described as the force between particles of the same substance that acts to unite them. Contrary to rheology, there are currently no ready-made instruments designed to measure cohesion, or methods which could be easily adapted to gels. To study and compare the possible clinical effects from the cohesive properties of a gel, it is necessary to standardize the definition and measurement of cohesion.
  
  
  OBJECTIVE
  The purpose of this study was to develop and evaluate methods for measuring cohesion.
  
  
  METHODS
  Three different methods were evaluated and compared with measures of perceived cohesion; compression force, dispersion in water and drop weight. Two different families of fillers (Emervel and Restylane) were used for evaluating the different methods.
  
  
  RESULTS
  The compression force did not reflect the measures of perceived cohesion. The dispersion method showed variable results over time, had some practical issues, and is evaluated by subjective assessment. The best correlation to the perceived cohesion was found with the drop weight method.
  
  
  CONCLUSIONS
  The drop weight method which closely resembles the definition of cohesion (IUPAC) was considered to be the best method for measuring cohesion.
authors.affiliation: Galderma, Uppsala, Sweden.
authors.forename: Katarina L M
authors.initials: KL
authors.lastname: Edsman
authors.forename: Åsa M
authors.initials: ÅM
authors.lastname: Wiebensjö
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Risberg
authors.forename: Jan Åke
authors.initials: JÅ
authors.lastname: Öhrlund
mesh_terms: D006801:Humans; D006820:Hyaluronic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D008422:Materials Testing / Q000379:methods*; D012212:Rheology / Q000379:methods*
chemical_list: D006820:Hyaluronic Acid; C445361:Restylane