Rechargeable anticandidal denture material with sustained release in saliva

Antifungal agents incorporated in denture base materials: a scoping review of the current evidence and technology prospecting

BACKGROUND

The aim of this study was to summarize existing data and perform technological prospecting on the effect of incorporating antifungal agents into denture base materials in inhibiting Candida spp., as well as to explore the antimicrobial properties of these materials.

METHODS

A comprehensive electronic search was carried out in six major bibliographic databases (PubMed, Scopus, Embase, Cochrane Library, Web of Science and Lilacs) until February 2024. In addition, international patent databases were also examined. The search process, study and patent selection, data extraction and risk of bias assessment were carried out independently by researchers. The collected data underwent qualitative analysis.

RESULTS

A total of 10 718 articles were identified in the searched databases, of which 40 documents were included for qualitative data analysis (articles: 31; patents: 9). The majority of the studies focused on investigating tissue conditioners (n = 14) and acrylic resins (n = 14). The primary antifungal agents studied were nystatin (n = 15) and fluconazole (n = 13). The most commonly utilized microbiological evaluation methodology was the agar diffusion test (n = 16), followed by the microdilution (n = 7) and biofilm formation assays (n = 7). All of the studies investigated the inhibitory effect of these materials against Candida species.

CONCLUSION

The incorporation of antifungal agents into denture base materials has been extensively studied and has shown a significant inhibitory response against Candida spp. across various methodological assays.

Prosthodontic implications of saliva and salivary gland dysfunction

PURPOSE

To provide a detailed overview of the fundamentals of saliva constituents and production. The review outlines the clinical manifestations as a consequence of salivary gland dysfunction and management strategies for patients with salivary gland dysfunction. Prosthodontic implications of saliva and salivary gland dysfunction are presented.

MATERIALS AND METHODS

English-language literature relating to saliva constituents, physiologic saliva production, clinical manifestations secondary to salivary gland dysfunction, salivary biomarkers, and management strategies were retrieved via electronic search. Relevant articles were summarized for this manuscript with a view toward providing pragmatic information.

RESULTS

Saliva is produced by three pairs of major and minor salivary glands. The major salivary glands, namely, the parotid, submandibular, and sublingual glands, contribute approximately 90% of saliva production. Saliva contains serous and mucinous secretions produced by different types of cells within salivary glands. Parasympathetic and sympathetic fibers innervate the major salivary glands, and upon stimulation, the parasympathetic innervation increases serous secretions, while the sympathetic innervation increases protein secretion. Stimulated saliva is mainly derived from the parotid glands which are composed of serous acini, while unstimulated saliva is mainly derived from the submandibular glands which are composed of mixed seromucous acini. As major salivary glands contribute the most to salivary flow, local or systemic factors influencing those glands can disrupt saliva production resulting in clinically significant oral manifestations.

CONCLUSION

This review provides a fundamental overview of saliva production. In addition, the review highlights the various clinical manifestations secondary to salivary gland dysfunction, explores salivary biomarkers for screening of systemic diseases, discusses management strategies for patients with salivary gland dysfunction, and outlines the prosthodontic implications of saliva and salivary gland dysfunction.

Highlights on Drug and Ion Release and Recharge Capacity of Antimicrobial Removable Prostheses

This article aimed to review the ion and drug release, recharge abilities, and antimicrobial properties of drug/ion-releasing removable prostheses, and to assess their capability in preventing and inhibiting denture stomatitis as well preventing caries and reversing carious lesions. Data was collected from published scientific papers listed in PubMed database from January 1975 to December 2021. English full-text articles, involving clinical or in vitro studies, focusing on removable prostheses and are concerned with drug/ion release and rechargeability as a way to prevent or inhibit denture stomatitis or dental caries were included. The relevant articles reported that ion- or drug-modified polymethylmethacrylate acts as a reservoir for these ions and drugs and is capable of releasing significant amounts with sustained release effect. Recharging of modified resin resulted in greater sustainability of ion and drug release, thus improving the long-term effects of protection against demineralization and reducing the adhesion of Streptococcus mutans and Candida albicans. Modifications of removable prostheses with rechargeable ions and drugs enhance remineralization, hinder demineralization, and reduce microbial adhesion in difficult-to-access areas. Selection of denture base for clinical use will consider its ability to act as an ion/drug reservoir that is capable of release and recharge.

Overview of incorporation of inorganic antimicrobial materials in denture base resin: A scoping review

STATEMENT OF PROBLEM

Dental hygiene for institutionalized patients and recurring Candida-associated denture stomatitis remain problematic because of a patient's limited dexterity or inability to eliminate Candida from denture surfaces. Although there has been extensive research into antimicrobial modification of denture base resins with inorganic materials, scoping reviews of the literature to identify knowledge gaps or efficacy of inorganic antimicrobial materials in denture base resins are lacking.

PURPOSE

The purpose of this scoping review was to provide a synopsis of the efficacy of the major classes of inorganic antimicrobial materials currently incorporated into denture base resins.

MATERIAL AND METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews was applied. Four electronic databases, including Embase, PubMed, Web of Science, and Google Scholar, were accessed for articles in the English language, up to February 2019, without restrictions on the date of publication.

RESULTS

From the 53 articles selected, 25 distinguishable inorganic materials were found and divided into 3 subgroups. Forty-three articles evaluated nanomaterials, where mostly silver ion nanoparticles and/or titanium dioxide nanoparticles were incorporated into denture base resins. Fourteen articles examined antimicrobial drugs and medications, including azole group medications, amphotericin-B, Bactekiller, chlorhexidine, Novaron, and Zeomic. Two articles classified as others explored hydroxyapatite- and fiber-incorporated denture base resins.

CONCLUSIONS

Although nanotechnology and antimicrobial medications or drugs have been successfully used to reduce Candida-associated denture stomatitis, long-term solutions are still lacking, and their disadvantages continue to outweigh their advantages.

Understanding the Mechanical, Surface, and Color Behavior of Oral Bioactive Prosthetic Polymers under Biodegradation Processes

Changes in the properties of resin-based polymers exposed to the oral environment can emerge when chlorhexidine (CHX) is incorporated to develop bioactive systems for treating denture stomatitis. Three reline resins loaded with CHX were prepared: 2.5 wt% in Kooliner (K), 5 wt% in Ufi Gel Hard (UFI), and Probase Cold (PC). A total of 60 specimens were submitted to physical aging (1000 cycles of thermal fluctuations, 5-55 °C) or chemical aging (28 days of pH fluctuations in artificial saliva, 6 h at pH = 3, 18 h at pH = 7). Knoop microhardness (30 s, 98 mN), 3-point flexural strength (5 mm/min), and surface energy were tested. Color changes (ΔE) were determined using the CIELab system. Data were submitted to non-parametric tests (α = 0.05). After aging, bioactive K and UFI specimens were not different from the controls (resins without CHX) in mechanical and surface properties. Thermally aged CHX-loaded PC specimens showed decreased microhardness and flexural strength but not under adequate levels for function. The color change was observed in all CHX-loaded specimens that underwent chemical aging. The long-term use of CHX bioactive systems based on reline resins generally does not impair removable dentures' proper mechanical and aesthetic functions.

Antifungal property of acrylic denture soft liner containing silver nanoparticles synthesized in situ

OBJECTIVES

Denture soft liner is applied to relieve pain from candida-induced denture stomatitis and promote healing, but with shortage of antifungal activity and easily harbors fungi. To overcome this problem, the in-situ method was used to synthesize silver nanoparticles (AgNPs) in acrylic soft liner to obtain antifungal effects.

METHODS

Acrylic soft-liner with various weight percentage of silver 2-ethylhexanoate (0%, 0.1 %, 0.2 %, 0.3 %) were prepared in 10 mm × 10 mm × 3 mm. After chemical polymerization, the diameter of AgNPs synthesized in situ and the degree of conversion of each group were measured. After 3, 7, and 14 days of storage in water, the antifungal rate (AFR) of in vitro direct contact antifungal assays and the antifungal test of non-cumulative extract solution were measured respectively. The release profiles of silver ions from the specimen within 14 days were also evaluated.

RESULTS

Evenly distributed AgNPs (4.7 nm-5.3 nm) were observed, and the degree of conversion had no significant difference among these groups. The AFR increased as the silver concentration rose, while decreasing with the storage time. After 14 days of water storage, the AFR of 0.2 % and 0.3 % groups still reached 63.38 % and 75.51 %, respectively. The non-cumulative extract solution had no antifungal effect.

CONCLUSIONS

Within the service life, the acrylic soft liner containing AgNPs synthesized in situ had effective control of Candida albicans through direct contact.

CLINICAL SIGNIFICANCE

This study suggests that AgNPs synthesized in situ may be an effective strategy in modifying acrylic denture soft liner to treat and prevent denture stomatitis.

Therapeutic tools for oral candidiasis: Current and new antifungal drugs

BACKGROUND

Candidiasis is one of the most common opportunistic oral infections that presents different acute and chronic clinical presentations with diverse diagnostic and therapeutic approaches. The present study carries out a bibliographic review on the therapeutic tools available against oral candidiasis and their usefulness in each clinical situation.

MATERIAL AND METHODS

Recent studies on treatment of oral candidiasis were retrieved from PubMed and Cochrane Library.

RESULTS

Nystatin and miconazole are the most commonly used topical antifungal drugs. Both antifungal drugs are very effective but need a long time of use to eradicate the infection. The pharmacological presentations of miconazole are more comfortable for patients but this drug may interact with other drugs and this fact should be assessed before use. Other topical alternatives for oral candidiasis, such as amphotericin B or clotrimazole, are not available in many countries. Oral fluconazole is effective in treating oral candidiasis that does not respond to topical treatment. Other systemic treatment alternatives, oral or intravenous, less used are itraconazole, voriconazole or posaconazole. Available novelties include echinocandins (anidulafungin, caspofungin) and isavuconazole. Echinocandins can only be used intravenously. Isavuconazole is available for oral and intravenous use. Other hopeful alternatives are new drugs, such as ibrexafungerp, or the use of antibodies, cytokines and antimicrobial peptides.

CONCLUSIONS

Nystatin, miconazole, and fluconazole are very effective for treating oral candidiasis. There are systemic alternatives for treating recalcitrant infections, such as the new triazoles, echinocandins, or lipidic presentations of amphotericin B.

Synthesis, Antifungal Activity, and Biocompatibility of Novel 1,4-Diazabicyclo[2.2.2]Octane (DABCO) Compounds and DABCO-Containing Denture Base Resins

The fungal pathogen Candida albicans causes a variety of oral infections, including denture stomatitis, which is characterized by inflammation of the oral mucosa in direct contact with dentures and affects a significant number of otherwise healthy denture wearers. While antifungal treatment reduces symptoms, infections are often recurrent. One strategy to address this problem is to incorporate compounds with fungicidal activities into denture materials to prevent colonization. Our laboratory synthesized novel derivatives of 1,4-diazabicyclo[2.2.2]octane (DABCO), which is an organic compound typically used as a catalyst in polymerization reactions. DABCO derivatives with different aliphatic chain lengths (DC16, DC16F, DC18, and C6DC16), as well as methacrylate monomers conjugated to DABCO compounds (DC11MAF and C2DC11MAF), were synthesized and tested for antimicrobial activity. All the compounds exhibited fungicidal activity against several Candida species at concentrations ranging between 2 and 4 μg/ml. Moreover, acrylic denture base resins fabricated to contain 1, 2, or 4 wt% DABCO compounds inhibited surface C. albicans biofilm formation, as well as fungal growth, in disc diffusion assays. Remarkably, discs (4 wt%) aged for 2 months also exhibited approximately 100% growth-inhibitory activity. While some DABCO compounds exerted intermediate to high cytotoxicity against mammalian oral cell types, DC11MAF and denture base resin discs containing 2 or 4 wt% C2DC11MAF exhibited relatively low cytotoxicity against periodontal ligament (PDL) cell and gingival fibroblast (GF) lines, as well as primary oral epithelial cells. These studies demonstrate that DABCO derivatives can be incorporated into denture materials and exert fungicidal activity with minimal cytotoxicity to mammalian cells. DC11MAF and C2DC11MAF are considered strong candidates as therapeutic or preventive alternatives against Candida-associated denture stomatitis.