Preventing proximal caries with glass ionomer cement restoration and silver diamine fluoride pretreatment

Abstract

Dental caries is the most common oral health problem worldwide, affecting people throughout their lifetime. In 2021, glass ionomer cement (GIC) was listed as a fluoride-containing product on the World Health Organization (WHO) Model List of Essential Medicine. This study started with a review to provide an overview of the clinical application of GIC with updated evidence in restorative and preventive dentistry. This initial review showed that GIC is a versatile dental material with a wide range of applications in restorative and preventive dentistry. It has been used as restorative material, luting cement for indirect restorations, liner and base of restorations, and dental sealants. A second review was performed to investigate the effectiveness of GIC restorations in preventing new caries compared with other types of restorations. The study found that GIC restorations exhibited better preventive effect on new caries than other types of restorations. CGIC demonstrated better preventive effect on new caries than resin-modified GIC (RMGIC) and amalgam restorations, but showed no statistical differences with composite resin restorations in primary dentition. RMGIC restorations showed no statistical differences in preventive effect on new caries compared with composite resin restorations. A third review was performed to compare the preventive effect on secondary caries of GIC restorations with amalgam or resin-composite restorations. The review found that GIC restorations showed a superior preventive effect against secondary caries compared to amalgam restorations, and a similar preventive effect against secondary caries compared to resin-composite restorations. To enhance the antimicrobial effect of GIC restoration, this study used silver diamine fluoride (SDF) solution as dentin pretreatment prior to GIC restoration. A first laboratory study assessed the fluoride and silver ion release of GIC restorations, including CGIC and RMGIC restorations, with 38% SDF solution dentin pretreatment. The results showed that 38% SDF dentin pretreatment sustainably increased the fluoride and silver release of GIC restorations for up to 2 years. Hence, the following laboratory studies used an in vitro model to investigate the enamel caries preventive effects of 38% SDF pretreatment on neighboring tooth proximal to GIC restorations. The results indicated that SDF pretreatment enhanced the preventive effect of GIC on proximal enamel surface on neighboring tooth through inhibiting cariogenic biofilm, reducing enamel demineralization and promoting enamel remineralization. After that the preventive effects of 38% SDF pretreatment on GIC restorations against root caries on neighboring tooth was investigated. The results showed that SDF pretreatment enhanced the preventive effect of GIC on the proximal dentin surface of neighboring tooth by inhibiting cariogenic biofilm, dentine demineralization and collagen degradation. SDF pretreatment enhanced the caries preventive effect of GIC restorations, while it introduced an extra step that increased the time required for operators and the treatment cost for patients. To address this challenge, we explored modifications on GIC materials. Hence, the fourth laboratory study was performed to develop an antimicrobial silver zeolite glass ionomer cement (SZ-GIC) and determine its biocompatibility, physical, adhesive and antibacterial properties. The results showed that SZ-GIC exhibited enhanced physical, adhesive and antibacterial properties compared to GIC.