title: Linear regression modeling to compare fluoride release profiles of various restorative materials.
abstract: OBJECTIVE
  The aim of this study was to compare the released fluoride profiles of various restorative materials by using linear regression analysis.
  
  
  METHODS
  Specimens were prepared using a cylindrical Teflon mold with a height of 2 mm and a radius of 8 mm. After being prepared, specimens were immediately placed into artificial saliva which was replaced at various times during 6 weeks. These released intrinsic fluoride amounts were measured by using an ion selective electrode. Then, data obtained cumulatively were statistically analyzed, and the released profiles were compared.
  
  
  RESULTS
  It was observed that the materials released fluoride at different levels of concentration and the largest fluoride release was obtained from the conventional glass ionomer cement. This was followed by resin modified glass ionomer cement, polyacid modified composite resin, and fluoride releasing composite resin, respectively. Although the released fluoride amounts of the materials were different, their release profiles were found to be similar in that the release was initially fast and then it became steady as time passed.
  
  
  CONCLUSIONS
  The statistical modeling of the release profiles helps to compare the fluoride release behavior of materials and also to predict fluoride release amounts for the future. In literature, for these purposes, separate nonlinear statistical models have extensively been utilized. However, the single linear statistical modeling approach has numerous advantages such as providing estimators having good statistical properties, exact results, precise inference and simplicity in calculation. Therefore, this study was conducted to introduce the use of single linear regression modeling to compare release profiles statistically.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, University of Ankara, Ankara 06500, Turkey. cdenizcank@yahoo.com
authors.forename: Deniz C
authors.initials: DC
authors.lastname: Can-Karabulut
authors.forename: Inci
authors.initials: I
authors.lastname: Batmaz
authors.forename: Hikmet
authors.initials: H
authors.lastname: Solak
authors.forename: Mustafa
authors.initials: M
authors.lastname: Taştekin
mesh_terms: D020770:Compomers / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent; D004058:Diffusion; D005459:Fluorides / Q000737:chemistry*; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D017736:Ion-Selective Electrodes; D016018:Least-Squares Analysis; D016014:Linear Models; D008422:Materials Testing; D019279:Resin Cements / Q000737:chemistry; D012464:Saliva, Artificial / Q000737:chemistry; D013997:Time Factors
chemical_list: C084111:Charisma composite resin; D020770:Compomers; D003188:Composite Resins; D003764:Dental Materials; C088486:Dyract; D005899:Glass Ionomer Cements; C467912:Photac-Fil Quick; D019279:Resin Cements; D012464:Saliva, Artificial; D005459:Fluorides