title: Efficacy of four preventive measures against enamel demineralization at the bracket periphery-comparison of microhardness and confocal laser microscopy analysis.
abstract: OBJECTIVE
  The aim of this in-vitro study was to investigate the efficacy of four preventive measures against enamel demineralization and to compare the suitability of microhardness (MH) measurements and confocal laser microscopy (CLSM).
  
  
  METHODS
  A total of 80 teeth were randomly allocated into four groups. The effect against demineralization of two coating materials (group 1: resin-modified glass ionomer (RMGI) cement varnish (ClinproXT); group 2: composite sealant (ProSeal)) and that of two types of bracket-bonding material (group 3: amorphous calcium phosphate (ACP) composite (AegisOrtho); group 4: RMGI (FujiOrthoLC)) was compared after pH-cycling by MH and CLSM. Measurements were made at the edge of the coating/bracket as well as at 50, 100, 200, and 400 μm distance. The data were converted into values of mineralization (Vol%) and analyzed by parametric (ANOVA and Tukey's post hoc) or non-parametric (Kruskal-Wallis and Games-Howell post hoc) tests.
  
  
  RESULTS
  ClinproXT and ProSeal were proved to protect the bracket periphery. However, the area next to them showed demineralizations. The mean area of lesion (CLSM-data) was significantly different between the groups (p < 0.0001). The smallest lesions were revealed for the RMGI-based materials. MH identified only for group 4 a significant difference between the area next to the bracket base and that at 200 and 400 µm distance.
  
  
  CONCLUSIONS
  There was nearly no lesion under both coatings. A stagnation of demineralization was identified particularly for the RMGI. ProSeal showed an inferior protection of the untreated enamel. MH and CLSM analysis were suitable to detect subsurface lesions.
  
  
  CONCLUSIONS
  A diverse efficacy of materials against enamel demineralization at bracket periphery has to be noticed.
authors.affiliation: Department of Orthodontics, Ludwig-Maximilians-University, Goethestr. 70, 80336, Munich, Germany. epaschos@med.uni-muenchen.de.
authors.forename: Ekaterini
authors.initials: E
authors.lastname: Paschos
authors.affiliation: Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Franz-Josef
authors.initials: FJ
authors.lastname: Geiger
authors.affiliation: Department of Restorative Dentistry, Periodontology and Pediatric Dentistry, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Yuriy
authors.initials: Y
authors.lastname: Malyk
authors.affiliation: Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Rudzki
authors.affiliation: Department of Orthodontics, Ludwig-Maximilians-University, Goethestr. 70, 80336, Munich, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Wichelhaus
authors.affiliation: Department of Restorative Dentistry, Periodontology and Pediatric Dentistry, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Nicoleta
authors.initials: N
authors.lastname: Ilie
mesh_terms: D002130:Calcium Phosphates / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006244:Hardness; D066298:In Vitro Techniques; D008422:Materials Testing; D018613:Microscopy, Confocal; D016910:Orthodontic Brackets; D010895:Pit and Fissure Sealants / Q000737:chemistry*; D013499:Surface Properties; D017001:Tooth Demineralization / Q000517:prevention & control*
chemical_list: D002130:Calcium Phosphates; C500418:Clinpro Sealant; D003188:Composite Resins; D005899:Glass Ionomer Cements; D010895:Pit and Fissure Sealants; C020243:calcium phosphate
keywords: ACP; CLSM; Demineralization; Microhardness; Sealant; White-spots