Xerostomia: From Pharmacological Treatments to Traditional Medicine-An Overview on the Possible Clinical Management and Prevention Using Systemic Approaches.

Despite high incidence rates and severe complications, the management of xerostomia lacks clinical guidelines. The aim of this overview was to summarize the clinical experience derived from the last 10 years of treatments and prevention using systemic compounds. Results showed that the cytoprotective drug amifostine, and its antioxidant agents, are the most discussed as preventive agents of xerostomia in head and neck cancer (HNC) patients. In the presence of the disease, the pharmacological treatments have been mainly directed to stimulate secretion of the damaged salivary glands, or to counteract a decreased capacity of the antioxidant system, in view of an increasing of reactive oxygen species (ROS). However, the data demonstrated low ability of the drugs, together with a great number of side effects, which strongly limit their use. Concerning traditional medicine (TM), valid clinical trials are so limited that neither the efficacy nor the absence of interferences to concomitant chemical therapies can be validated. Consequently, the management of xerostomia and its devastating complications remain a very significant void in daily clinical practice.

Antimicrobial Effect of Thymus capitatus and Citrus limon var. pompia as Raw Extracts and Nanovesicles.

In view of the increasing interest in natural antimicrobial molecules, this study screened the ability of Thymus capitatus (TC) essential oil and Citrus limon var. pompia (CLP) extract as raw extracts or incorporated in vesicular nanocarriers against Streptococcus mutans and Candida albicans. After fingerprint, TC or CLP were mixed with lecithin and water to produce liposomes, or different ratios of water/glycerol or water/propylene glycol (PG) to produce glycerosomes and penetration enhancer vesicles (PEVs), respectively. Neither the raw extracts nor the nanovesicles showed cytotoxicity against human gingival fibroblasts at all the concentrations tested (1, 10, 100 µg/mL). The disc diffusion method, MIC-MBC/MFC, time-kill assay, and transmission electron microscopy (TEM) demonstrated the highest antimicrobial potential of TC against S. mutans and C. albicans. The very high presence of the phenol, carvacrol, in TC (90.1%) could explain the lethal effect against the yeast, killing up to 70% of Candida and not just arresting its growth. CLP, rich in polyphenols, acted in a similar way to TC in reducing S. mutans, while the data showed a fungistatic rather than a fungicidal activity. The phospholipid vesicles behaved similarly, suggesting that the transported extract was not the only factor to be considered in the outcomes, but also their components had an important role. Even if other investigations are necessary, TC and CLP incorporated in nanocarriers could be a promising and safe antimicrobial in caries prevention.

The role of adhesive materials and oral biofilm in the failure of adhesive resin restorations.

PURPOSE: To critically discuss adhesive materials and oral cariogenic biofilm in terms of their potential relevance to the failures of adhesive restorations in the oral environment. METHODS: The literature regarding adhesive restoration failures was reviewed with particular emphasis on the chemistry of adhesive resins, weakness in dentin bonding, water fluids, cariogenic oral biofilm and the relations that influence failures. Particular attention was paid to evidence derived from clinical studies. RESULTS: There was much evidence that polymerization shrinkage is one of the main drawbacks of composite formulations. Stress results in debonding and marginal leakage into gaps with deleterious effects in bond strength, mechanical properties and the whole stability of restorations. Changes in resins permit passage of fluids and salivary proteins with a biological breakdown of the restorations. Esterases enzymes in human saliva catalyze exposed ester groups in composite producing monomer by-products, which can favor biofilm accumulation and secondary caries. Adhesive systems may not produce a dense hybrid layer in dentin. Very often this is related to the high viscous solubility and low wettability in dentin of the hydrophobic BisGMA monomer. Thus, dentin hybrid layer may suffer from hydrolysis using both the Etch&Rinse and Self-Etching adhesive systems. In addition, exposed and non-resin enveloped collagen fibers may be degraded by activation of the host-derived matrix metalloproteinase. Plaque accumulation is significantly influenced by the surface properties of the restorations. Biofilm at the contraction gap has demonstrated increased growth of Streptococcus mutans motivated by the chemical hydrolysis of the adhesive monomers at the margins. Streptococcus mutans is able to utilize some polysaccharides from the biofilm to increase the amount of acid in dental plaque with an increase in virulence and destruction of restorations. Stability of resin restorations in the oral environment is highly dependent on the structure of the monomers used in composite and adhesive systems. Still, the issues related to microleakage of fluids into the gap and bacteria leaching from the surface of composites represent the main causes of failure of adhesive restorations. CLINICAL SIGNIFICANCE: Modifications of adhesive materials are necessary to address their instability in the oral environment.