The Manufacture and Characterization of Silver Diammine Fluoride and Silver Salt Crosslinked Nanocrystalline Cellulose Films as Novel Antibacterial Materials.

John Jackson,Claudia Dietrich,Ali Shademani,Adriana Manso

doi:10.3390/gels7030104

Abstract

There is an unmet need for biocompatible, anti-infective, and mechanically strong hydrogels. This study investigated the use of poly vinyl alcohol (PVA), polysaccharides, and nanocrystalline cellulose (CNC) to deliver silver in a controlled manner for possible use against oral or wound bacteria. Silver was included in solvent cast films as silver diammine fluoride (SDF) or as nitrate, sulphate, or acetate salts. Hydrogel formation was assessed by swelling determinations and silver release was measured using inductively coupled plasma methods. Antibacterial studies were performed using Gram-positive and negative bacteria turbidity assays. PVA formed homogenous, strong films with SDF and swelled gently (99% hydrolyzed) or vigorously with dissolution (88% hydrolyzed) and released silver slowly or quickly, respectively. CNC-SDF films swelled over a week and formed robust hydrogels whereas CNC alone (no silver) disintegrated after two days. SDF loaded CNC films released silver slowly over 9 days whereas films crosslinked with silver salts were less robust and swelled and released silver more quickly. All silver loaded films showed good antibacterial activity. CNC may be crosslinked with silver in the form of SDF (or any soluble silver salt) to form a robust hydrogel suitable for dental use such as for exposed periodontal debridement areas.

Highlights

Infections associated with dental procedures remain a challenging problem for clinicians
Considering the renewed interest in the use of silver products as anti-infective wound dressings and the use of silver diammine fluoride (SDF) in dentistry, the objective of this study was to explore the use of swelling hydrogel—forming biomaterials such as hyaluronic acid (HA), carboxymethyl cellulose (CMC), poly vinyl alcohol (PVA), and CNC as delivery systems for SDF in medical applications
Films made from SDF in CMC or HA failed to form homogenous materials

Summary

Introduction

Infections associated with dental procedures remain a challenging problem for clinicians. Oral bacterial infections are difficult to treat because there is a constant exposure to bacteria that is difficult to prevent [1]. Systemic antibiotics may have limited access to infected areas such as in periodontal, periapical, or root canal systems. Periodontal infections are often treated by gingival flap exposure, debridement, and surface treatment to encourage bone and gingival tissue regrowth [3], but bacterial infections in such procedures have frequent recurrence [4]. In root canal settings the drilled channel is usually filled with gutta percha and endodontic cement as a permanent material before crown fixation, yet this material has little or no antibiotic activity [6]. In dental caries lesion treatments, newer non-amalgam fillings often require revisions due to subsequent biofilm formation and recurrent caries lesions [7]

Objectives

Methods

Results