title: Study on the influence of leucine-rich amelogenin peptide (LRAP) on the remineralization of enamel defects via micro-focus x-ray computed tomography and nanoindentation.
abstract: Regeneration of severely damaged enamel (e.g. deep demineralized lesions) is currently not possible, because the structural units of enamel crystal construction are removed after its maturation. The aim of this in vitro study was to evaluate the effect of surface impregnation by leucine-rich amelogenin peptide (LRAP) on the remineralization of eroded enamel using micro-focus x-ray computed tomography (µCT). Fifteen bovine enamel blocks were embedded in resin and three zones (sound, demineralization, and remineralization) were defined on each specimen. Lesions were prepared by immersing the samples in demineralization solution for 7 d. The samples were soaked in distilled water or 60 or 120 µg mL(-1) solution of LRAP in water for 30 min. After the surface treatment, specimens were incubated in artificial saliva for either 5 or 10 d at 37 °C. The amount of mineral gain (dΔZ%) and the relative changes in the lesion depth (dLD%), obtained from µCT, were used to evaluate the effect of LRAP on the remineralization of lesions. The effects of LRAP on cross-sectional integrated hardness ΔINH were studied after 10 d using nanoindentation. ANOVA test was used to determine the effect of time and/or LRAP concentration on dΔZ%, dLD% and ΔINH mean values. Tukey's analysis was used for multiple comparison testing (α = 0.05). Analysis of µCT data showed significant effect of time and LRAP concentration on the dΔZ% (p = 0.013, p = 0.003) and the dLD% (p  <  0.001, p = 0.002) mean values. The nanoindentation hardness was significantly improved by 120 µg mL(-1) LRAP (p = 0.02). Also, the peptide treatment affected the mineral distribution throughout the lesion by inhibiting of superficial deposition. This study showed that the treatment of eroded lesions in enamel by LRAP can improve and regulate the pattern of remineralization in vitro.
authors.affiliation: Research Center for Science and Technology in Medicine/Dental Biomaterials Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran. Cariology and Operative Dentistry Department, Tokyo Medical and Dental University, Tokyo, Japan. School of Dentistry, Tehran University of Medical Sciences, Northern Kargar str., Hakim Highway, Tehran, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Bagheri G
authors.forename: Alireza
authors.initials: A
authors.lastname: Sadr
authors.forename: Jorge
authors.initials: J
authors.lastname: Espigares
authors.forename: Ilnaz
authors.initials: I
authors.lastname: Hariri
authors.forename: Syozi
authors.initials: S
authors.lastname: Nakashima
authors.forename: Hidenori
authors.initials: H
authors.lastname: Hamba
authors.forename: Farhad
authors.initials: F
authors.lastname: Shafiei
authors.forename: Fathollah
authors.initials: F
authors.lastname: Moztarzadeh
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
mesh_terms: D000818:Animals; D002417:Cattle; D003743:Dental Enamel / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000503:physiopathology; D003746:Dental Enamel Proteins / Q000008:administration & dosage*; D003764:Dental Materials; D006244:Hardness / Q000187:drug effects / Q000502:physiology; D006245:Hardness Tests; D066298:In Vitro Techniques; D008422:Materials Testing; D012996:Solutions; D013552:Swine; D017001:Tooth Demineralization / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology; D014089:Tooth Remineralization / Q000379:methods*; D055114:X-Ray Microtomography
chemical_list: D003746:Dental Enamel Proteins; D003764:Dental Materials; D012996:Solutions; C067432:leucine-rich amelogenin peptide