title: Histochemical changes of occlusal surface enamel of permanent teeth, where dental caries is questionable vs sound enamel surfaces.
abstract: OBJECTIVE
  This in vitro study was to classify questionable for caries occlusal surfaces (QCOS) of permanent teeth according to ICDAS codes 1, 2, and 3 and to compare them in terms of enamel mineral composition with the areas of sound tissue of the same tooth.
  
  
  METHODS
  Partially impacted human molars (60) extracted for therapeutic reasons with QCOS were used in the study, photographed via a polarised light microscope and classified according to the ICDAS II (into codes 1, 2, or 3). The crowns were embedded in clear self-cured acrylic resin and longitudinally sectioned at the levels of the characterised lesions and studied by SEM/EDX, to assess enamel mineral composition of the QCOS. Univariate and multivariate random effect regressions were used for Ca (wt%), P (wt%), and Ca/P (wt%).
  
  
  RESULTS
  The EDX analysis indicated changes in the Ca and P contents that were more prominent in ICDAS-II code 3 lesions compared to codes 1 and 2 lesions. In these lesions, Ca (wt%) and P (wt%) concentrations were significantly decreased (p = 0.01) in comparison with sound areas. Ca and P (wt%) contents were significantly lower (p = 0.02 and p = 0.01 respectively) for code 3 areas in comparison with codes 1 and 2 areas. Significantly higher (p = 0.01) Ca (wt%) and P (wt%) contents were found on sound areas compared to the lesion areas.
  
  
  CONCLUSIONS
  The enamel of occlusal surfaces of permanent teeth with ICDAS 1, 2, and 3 lesions was found to have different Ca/P compositions, necessitating further investigation on whether these altered surfaces might behave differently on etching preparation before fissure sealant placement, compared to sound surfaces.
authors.affiliation: Department of Paediatric Dentistry, School of Dentistry, University of Athens, 2 Thivon Str., Goudi, 115 27, Athens, Greece. mmichal@dent.uoa.gr.
authors.forename: M
authors.initials: M
authors.lastname: Michalaki
authors.affiliation: Department of Paediatric Dentistry, School of Dentistry, University of Athens, 2 Thivon Str., Goudi, 115 27, Athens, Greece.
authors.forename: C J
authors.initials: CJ
authors.lastname: Oulis
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, School of Dental Medicine/Medical Faculty, University of Bern, Bern, Switzerland.|, Corfu, Greece.
authors.forename: N
authors.initials: N
authors.lastname: Pandis
authors.affiliation: Department of Biomaterials, School of Dentistry, University of Athens, 2 ThivonStr, Goudi, 115 27, Athens, Greece.
authors.forename: G
authors.initials: G
authors.lastname: Eliades
mesh_terms: D002118:Calcium / Q000032:analysis; D003188:Composite Resins / Q000737:chemistry; D003731:Dental Caries / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000473:pathology*; D003743:Dental Enamel / Q000737:chemistry* / Q000000981:diagnostic imaging* / Q000473:pathology*; D019229:Dentition, Permanent; D006801:Humans; D008964:Molar, Third / Q000000981:diagnostic imaging / Q000473:pathology; D010758:Phosphorus / Q000032:analysis; D019252:Radiography, Dental, Digital; D013499:Surface Properties
chemical_list: D003188:Composite Resins; D010758:Phosphorus; D002118:Calcium
keywords: Altered enamel composition; ICDAS-II codes 1 and 2; Incipient lesions; Questionable for caries occlusal surfaces