Effects of Irradiation on in situ Remineralization of Human and Bovine Enamel Demineralized in vitro

Abstract

The objective of this study was to evaluate the effects of irradiation and surface condition on in situ remineralization of demineralized human and bovine enamel. Specimens (n = 96) obtained from 24 human molars and 24 bovine incisors were prepared. The surfaces of half of the specimens were abraded while the others remained natural. Each of the 12 human and bovine abraded and sound specimens was irradiated fractionally up to 46.5 Gy (3.1 Gy/day, 5 days/week), while the remaining samples were not irradiated. Prior to and following the demineralization (pH 5.0; 14 days) all specimens were partly covered with nail varnish (control). After in vitro demineralization 2 irradiated and 2 nonirradiated specimens were inserted into both buccal aspects of 12 intraoral appliances, which were worn by 12 persons for a period of 6 weeks. All samples were brushed twice a day with a fluoride-containing toothpaste. Mineral analyses revealed a significant influence on mineral loss (ΔZ_demin), mineral gain (ΔΔZ), lesion depth (LD_demin), and lesion depth reduction (ΔLD) of the variables ‘material’ and ‘irradiation’ (p < 0.05; ANOVA). Reciprocal interactions could be observed between these two variables for ΔZ_demin, ΔΔZ, and LD_demin, due to significantly reduced values found for the irradiated, abraded bovine specimens compared to the nonirradiated ones (p < 0.05; Bonferroni post hoc test). It can be concluded that neither irradiation nor abrasion influenced in vitro demineralization or in situ remineralization of the human specimens, whereas abrasion hampered demineralization in irradiated, bovine specimens.

Bovine teeth as substitute for human teeth in dental research: a review of literature

“…Therefore, 68 papers were included in the final review. The studies covered seven main categories: morphology (5 studies) (22)(23)(24)(25)(26), chemical composition (11 studies) (27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37), physical properties (12 studies) (38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49), dental caries (7 studies) (6,9,(50)(51)(52)(53)(54), dental erosion/abrasion (10 studies) (55)(56)(57)(58)(59)(60)(61)(62)(63)(64), bonding/adhesive strength (17 studies) (65)(66)(67)(68)…”

“…Dental caries studies Table 1 shows the details of the seven studies reviewed (6,9,(50)(51)(52)(53)(54). There were four in vitro studies (6,9,50,51), one in situ study (52), and two in vitro/in situ studies (53,54).…”

Effect of high energy X-ray irradiation on the nano-mechanical properties of human enamel and dentine

“…16,17,24,25,26,27 However, only limited information is available concerning these effects on both enamel and dentine. Moreover, most of the previous investigations had limitations with regard to the instruments used, and there has been little study concerning the relationship between radiation dose and mechanical properties.…”

“…2,12,13 However, in recent years, some scientists have suggested that direct radiation damage can ratchet up the progression of radiation caries; in their studies, morphological and physical changes in both human and bovine dentine were documented after radiotherapy. 14,15,16,17 Unfortunately, the explanation regarding changes in the nano-mechanical properties of teeth has generated controversy in dental literature, and no in vivo study has reported the crucial radiotherapy dose-time relationship regarding the prevention of radiation caries. In vitro studies have limitations with regard to clinical conclusions.…”

Estudo in situ da resistência à desmineralização do esmalte dental submetido à irradiação com laser Er,Cr:YSGG associada ao uso de produtos fluoretados

“…No experimento in vitro foi observada diferença significativa entre os No estudo in situ, a radiação gama, para esterilização das amostras de esmalte utilizadas no dispositivo, não interferiu na diminuição da desmineralização ou na ativação da remineralização, como prevê a literatura [Kielbassa et al, 2006] Desta maneira, a maior adsorção causa um efeito prolongado da aplicação profissional (FFA + laser), em ambiente clínico. O uso de dentifrício, em ambiente doméstico, mantém o contínuo aporte de fluoreto para a formação de produtos de superfície de esmalte, solicitados nos ciclos de pH.…”