title: Effects of chlorhexidine and fluoride on irradiated enamel and dentin.
abstract: The effectiveness of mouthwash protocols in preventing gamma irradiation therapy damage to the ultimate tensile strength (UTS) of enamel and dentin is unknown. It was hypothesized that the use of chlorhexidine and fluoride mouthwash would maintain the UTS of dental structures. One hundred and twenty teeth were divided into 2 groups: irradiated (subjected to 60 Gy of gamma irradiation in daily increments of 2 Gy) and non-irradiated. They were then subdivided into 2 mouthwash protocols used 3 times per day: 0.12% chlorhexidine, 0.05% sodium fluoride, and control group (n = 10). The specimens were evaluated by microtensile testing. The results of the Tukey test (p < 0.05) indicated that the gamma irradiation therapy significantly reduced the UTS of the enamel, crown, and root dentin. Macromolecular alterations were suggested by optical retardation data in dentin. Structural alterations, in both substrates, were detected by scanning electron microscopy analysis. Mouthwash with 0.12% chlorhexidine partially prevented the damage to the mechanical properties of the irradiated crown dentin, whereas the 0.05% sodium-fluoride-irradiated enamel showed UTS similar to that of non-irradiated enamel.
authors.affiliation: Biomechanics Group, School of Dentistry, Federal University of Uberlândia, Dept. of Operative Dentistry and Dental Materials, Av. Pará 1720, Bloco 2B, Sala 2B-24, Campus Umuarama, Uberlândia, MG 38400-902, Brazil. carlosjsoares@umuarama.ufu.br
authors.forename: C J
authors.initials: CJ
authors.lastname: Soares
authors.forename: N A
authors.initials: NA
authors.lastname: Neiva
authors.forename: P B F
authors.initials: PB
authors.lastname: Soares
authors.forename: P
authors.initials: P
authors.lastname: Dechichi
authors.forename: V R
authors.initials: VR
authors.lastname: Novais
authors.forename: L Z
authors.initials: LZ
authors.lastname: Naves
authors.forename: M R
authors.initials: MR
authors.lastname: Marques
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002710:Chlorhexidine / Q000494:pharmacology*; D003743:Dental Enamel / Q000737:chemistry / Q000528:radiation effects*; D003799:Dental Stress Analysis; D003804:Dentin / Q000737:chemistry / Q000528:radiation effects*; D005720:Gamma Rays / Q000009:adverse effects*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D009067:Mouthwashes / Q000494:pharmacology*; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D012969:Sodium Fluoride / Q000494:pharmacology*; D018709:Statistics, Nonparametric; D013718:Tensile Strength / Q000187:drug effects / Q000528:radiation effects; D019228:Tooth Crown / Q000528:radiation effects; D014092:Tooth Root / Q000528:radiation effects; D055815:Young Adult
chemical_list: D009067:Mouthwashes; D011837:Radiation-Protective Agents; D012969:Sodium Fluoride; D002710:Chlorhexidine