Effect of various dentin disinfection protocols on the bond strength of resin modified glass ionomer restorative material

Effect of a novel quaternary ammonium silane based cavity cleanser FiteBac 2% K21 QAS in comparison with other cavity disinfectants on the bond strength of resin-modified glass ionomer cement

Background

The application of cavity cleansers for cavity disinfection can be a crucial step in the longevity of restorations. The objective of the present study was to compare the effect of the application of a new quaternary ammonium silane (QAS)-based cavity cleanser (2% K21 QAS), with other commercially available cavity disinfectants on the bond strength of resin-modified glass ionomer cement (RMGIC).

Materials and Methods

The buccal surfaces of 40 extracted premolars were trimmed to obtain a flat dentinal surface and were randomly divided into four experimental groups depending on the cavity cleansers used before restoration. Group 1: 2% chlorhexidine (CHX), Group 2: QAS (FiteBac 2% K21 QAS), Group 3: silver diamine fluoride-potassium iodide (Riva Star, SDF-KI), and Group 4: 3% hydrogen peroxide (H2O2). Then, a predetermined dimension of RMGIC restoration was bonded to the treated dentin surfaces. Following this, each sample was tested for shear bond strength (SBS) using a universal testing machine at a crosshead speed of 0.5 mm/min.

Results

Among the experimental groups, SDF-KI has shown the highest mean SBS, followed by 2% K21 QAS, and 2% CHX, which have shown almost comparable results. The 3% H2O2 group has shown the lowest values.

Conclusion

According to the results of the present study, 2% K21 QAS has the potential to be used as an effective cavity cleanser before the placement of RMGIC restorations. Since its application does not affect the bond strength of restoration, it can be successfully used as an alternative to CHX and SDF-KI.

[Potentialities of photoactivated disinfection in dentistry]

Infection control is an essential part of dental practice. Oral antiseptics should be highly effective against the most common oral pathogens without causing microbial resistance, biocompatible with the human tissues with no interaction with fillings materials. Photoactivated disinfection (PAD) is based on activation of photosensitizers - specific substances releasing active oxygen forms after absorption of the light. The active oxygen forms destroy bacterial cell structures without affecting human cells. The overwhelming majority of Russian and international researchers have reported high effectiveness of PAD in periodontics, implantology and endodontics, whereas the use of PAD in caries treatment and prevention is not so fully understood yet. Earlier studies have demonstrated high sensitivity of cariogenic bacteria to PAD, suggesting it as an additional minimally invasive caries therapy improving treatment effectiveness. PAD spares dental tissues without reduction in the effectiveness of disinfection. It is particularly important in treatment of deep carious lesions and disinfection of thin dentine layer near the pulp. Effectiveness of PAD in caries treatment has been demonstrated for both permanent and deciduous dentition. PAD doesn't affect bond strength to fillings, improves plasticity of dental pulp and dental hard tissues mineralization in children. Effective control of a wide range of bacteria without causing resistance makes PAD a prospective method of treatment and prevention of caries.

Effect of silver diamine fluoride-potassium iodide and 2% chlorhexidine gluconate cavity cleansers on the bond strength and microleakage of resin-modified glass ionomer cement

Background:

Disinfection of the prepared cavity can be a crucial step in the longevity of restorations. The objective of this study was to compare the antimicrobial action (AMA) of silver diamine fluoride-potassium iodide combination (SDF-KI) with 2% chlorhexidine gluconate (CHX) and to compare the alteration in bond strength and microleakage while using SDF-KI and CHX as cavity cleansers in resin-modified glass ionomer cement (RMGIC) restorations.

Materials and Methods:

Samples were grouped as follows: Group 1: Polyacrylic acid (PAA), Group 2: CHX, Group 3: SDF-KI, and Group 4: Distilled water (CTRL). AMA was assessed by measuring the zone of inhibition of the above-mentioned materials by dispensing them into the punch hole prepared on agar plates with an inoculum of Streptococcus mutans. For assessing the effect of the cavity cleansers on the bond strength of RMGIC, they were applied to the dentinal samples prepared from freshly extracted noncarious molars. After the surface was treated, cylindrical restoration of RMGIC was placed and allowed to set. The shear bond strength was then evaluated using a universal testing machine. Rhodamine-B dye penetration was viewed under a fluorescent microscope to evaluate the microleakage of RMGIC following surface treatment of the standardized cavities prepared on the cervical third of freshly extracted noncarious premolars.

Results:

SDF-KI (34 ± 0.8 mm) showed potent AMA followed by CHX (23.9 ± 0.7 mm) and PAA (12.7 ± 0.8 mm). SDF-KI showed a drastic increase in the bond strength when compared to the PAA, CHX, and CTRL groups. Although the application of SDF-KI showed the least microleakage among all the groups, it was not statistically significant.

Conclusion:

The application of SDF-KI and CHX is useful against S. mutans in an in vitro study. Although SDF-KI group showed the least microleakage among the groups, it was not statistically significant. SDF-KI application has shown a drastic increase in the bond strength of RMGIC although further research is required for the suitable reasoning of the phenomenon.

Glass Ionomer Cements for the Restoration of Non-Carious Cervical Lesions in the Geriatric Patient

Background: The restoration of non-carious cervical lesions in geriatric patients is a demanding process. Glass ionomer cements can be promising materials for the management of these lesions in older adults. The aim of this literature review is to present the benefits of glass ionomers and how they can be used for the restoration of non-carious cervical lesions of older adults depending on the geriatric patient’s profile. Data sources: All available in vitro and in vivo studies from Google Scholar, PubMed and Scopus search engines corresponding to glass ionomer cements, geriatric dentistry, elderly patients, and non-carious lesions as key words were reviewed. Data synthesis: The advantages of glass ionomer cements, such as good retention and fluoride release, make them suitable for the restoration of non-carious cervical lesions. However, several factors related to the geriatric patient’s profile determine the most suitable material type. Conclusion: In general, the resin modified glass ionomer cements (RMGICs) appear to be preferred, but under certain circumstances the use of the conventional product is more appropriate, despite its poorer mechanical features. Further studies are required for more reliable data analysis and clinical interpretation of the relevant results.