Ion exchanges between glass-ionomer restorative material and primary teeth components-an in vivo study

Abstract

Objectives: To analyze the ion exchange between conventional glass-ionomer restorative material, (Fuji IX-GC Co., Japan) and tooth components in primary molars after long periods of function in vivo. Methods: Five deciduous mandibular molars were collected after normal exfoliation. An intact deciduous molar served as control, a second deciduous molar was restored occlusaly with Fuji IX in vitro, and 3 deciduous molars with occlusal restorations were collected after 18, 24, and 48 months in vivo. The molars were sectioned bucco-lingual through the restoration and the chemical analysis was performed on enamel, dentin and restorative material along parallel lines crossing from buccal to lingual, using an energy dispersive X-ray spectrometer (EDS). The data was analyzed using SPSS program. Results: In the enamel adjacent to the glass-ionomer material, calcium and phosphate showed a significant reduction related to time (P<0.05). In both enamel and dentin strontium, silica and alumina migrated from the glass-ionomer material in significant concentrations (P<0.05), and fluorine showed an increase from zero in the intact deciduous molar to 1.2% after four years in vivo. In the glass-ionomer material fluorine was reduced in relation with time in vivo, while calcium concentration increased. Conclusions: There is a constant exchange of ions between glass-ionomer restorative material and tooth components in deciduous molars. It begins as early as two weeks in vitro and is increased in vivo. Strontium, alumina and fluorine released from the glassionomer have a bactericidal effect and may affect remineralization. Calcium may enhance the glass-ionomer mineralization and transform it into enamel like material. Clinical significance: The results showed that a continuous exchange of ions between enamel and dentin and glass-ionomer material occurs in vivo and the concentration of the ions is time related. Strontium, alumina and fluorine in enamel and dentin may cause a continuous anti bacterial and anti cariogenic effect, while calcium enhance mineralization of glass-ionomer in vivo, a factor that may increase the longevity of the restoration.

Remineralizing Effect of Nanofilled Glass Ionomer Combined with Titanium Dioxide Nanoparticle and Nanohydroxyapatite in Root Caries-like Lesions

“…The potential of remineralization of carious lesions in dentin in vitro by glass-ionomer cements (GIC) has been long established, and related to the release of fluoride ions from the restorative material. Diffusion of additional ions from GIC, like calcium, and phosphate has an additional effect on remineralized dentin in vivo in permanent teeth (26) . Those results are in agreement with others studies (27,28) , which showed significant remineralization effect of Nano glass ionomer on dentin.…”

Next generational fuji IX-a proposed universal dental material–but not yet 'set in cement'

“…The resultant bond is therefore not weak. Strong and significant bonding of glass ionomers to underlying tooth structure is due to chemical bonding interactions with the mineral phase of underlying tooth [23] aided by the evident ion-exchanges [2]. It ought to be noted that reactive, sclerotic dentine under carious lesions has a different mineral composition as compared to non-carious, non-deminerlized dentine substrate.…”

“…Importantly, fluorine showed a dramatic presence within the surrounding tooth after four years in vivo. Calcium exchange into the restorative material was also observed [2]. Ions such as strontium, alumina and fluorine migrating from the glass ionomer restorative into the surrounding dental structures may be presumed to possess a bactericidal/anti-cariogenic influence and may also enhance remineralization.…”

“…An analysis has been very recently presented regarding ion exchange between conventional glass-ionomer restorative material-FujiIX-and tooth [2]. This study is instructive in that for both enamel and dentine adjacent to glass ionomer cement restoration strontium, silica and alumina ions diffused from the restorative into the tooth substance.…”

“…Ions such as strontium, alumina and fluorine migrating from the glass ionomer restorative into the surrounding dental structures may be presumed to possess a bactericidal/anti-cariogenic influence and may also enhance remineralization. Calcium ion exchange into the restorative may, in turn, aid in transforming the material into a more robust, enamel-like material [2]. The fact that these ionic movements occur actively in vivo over time is of significant clinical import and speaks highly in itself for the usefulness of glass ionomers in dentistry.…”