Chlorhexidine: is it still the gold standard?

Chitosan nanoparticles loaded with epigallocatechin-3-gallate: synthesis, characterisation, and effects against Streptococcus mutans biofilm

This study evaluated the effects of chitosan nanoparticles loaded with epigallocatechin-3-gallate (EGCG) against Streptococcus mutans biofilm. EGCG-loaded chitosan (Nchi + EGCG) nanoparticles and Chitosan (Nchi) nanoparticles were prepared by ion gelation process and characterised regarding particle size, polydispersion index, zeta potential, and accelerated stability. S mutans biofilms were treated twice daily with NaCl 0.9% (negative control), Nchi, Nchi + EGCG, and chlorhexidine (CHX) 0.12% (positive control). After 67 h, the biofilms were evaluated for acidogenesis, bacterial viability and dry weight. Biofilm morphology and structure were analysed by scanning electron microscopy. The nanoformulations presented medium to short-term stability, size of 500 nm, and polydispersion index around 0.400. Treatments affected cell morphology and biofilm structure. However, no effects on microbial viability, biofilm dry weight, and acidogenesis were observed. Thus, the nanoformulations disassembled the biofilm matrix without affecting microbial viability, which makes them promising candidates for the development of dental caries preventive and therapeutic agents.

Impact of modifications on the characteristics of salivary pellicle on dental hard tissue: a scoping review

OBJECTIVES

The salivary pellicle regulates interfacial events on dental surfaces and is a promising target for modification to improve dental health. This scoping review systematically examines substances that modify the pellicle, evaluating their potential and identifying knowledge gaps.

DATA

This review followed the PRISMA-ScR guidelines. Studies investigating how substances applied during pellicle formation on enamel or dentin affect its structure, composition, or protective function were included.

SOURCES

A systematic search of Medline was conducted up to March 2024 using predefined terms. Only English-language research articles were included. No hand-searching was performed.

STUDY SELECTION

A total of 864 records were identified. After title and abstract screening, 110 articles were assessed in full, resulting in 85 eligible studies for data charting. These studies investigated human saliva-derived pellicles on enamel or dentin, comparing their composition, structure, or protective properties with and without modification. Most studies, conducted equally in vitro and in situ, focused on fluorides and metals (n = 28), peptides and proteins (n = 21), and polyphenols (n = 18), while other substances were less frequently examined (n = 17). Modifications affected the pellicle's ultrastructure, altered its proteome, or enhanced its protective role against erosion, abrasion, and bacterial adherence.

CONCLUSIONS

Despite numerous studies and distinct substance classes, findings remain inconclusive and must be interpreted within the context of individual study designs.

CLINICAL SIGNIFICANCE

Modifying the pellicle can improve its protective function, presenting a promising approach for preventive dentistry. However, the long-term effects of these substances within the dynamic oral environment remain unclear. This review underscores the need for further research to close existing knowledge gaps and confirm clinical relevance.

Efficacy of localized sustained-release drugs in periodontitis and comorbid diabetes: A systematic review and meta-analysis

Our meta-analysis aimed to evaluate the efficacy of localized sustained-release drugs in periodontitis and comorbid diabetes. PubMed, Cochrane Library, Embase, and Web of Science were comprehensively searched until 4 December 2024, and 10 randomized controlled trials (RCTs) were included. The results indicated that, compared to the control group, localized sustained-release drugs significantly reduced probing depth (PD) (SMD = -0.77, 95% confidence interval [CI] (-1.37, -0.16)) but did not reduce clinical attachment loss (CAL) (SMD = -0.18, 95% CI (-0.60, 0.23)), sites with glycated hemoglobin (HbA1c) (SMD = 0.03, 95% CI (-0.38, 0.43)), plaque index (SMD = -0.37, 95% CI (-0.80, 0.06)), sites with bleeding on probing (BOP) (SMD = -0.26, 95% CI (-0.68, 0.16)), and gingival index (SMD = 0.07, 95% CI (-0.30, 0.44)). Subgroup analysis by different drugs elicited that, compared to the control treatment, chlorhexidine was effective in reducing BOP% (SMD = -0.55, 95% CI (-0.90, -0.19)). Our meta-analysis finds that the efficacy of localized sustained-release drugs in periodontitis and comorbid diabetes is limited.

Antibacterial Activity and Randomised Controlled Trial of Chlorhexidine-Coated Floss on Gingival Bleeding

INTRODUCTION

While Chlorhexidine mouthwash is widely studied for the treatment of periodontal disease, research on chlorhexidine in the form of dental floss is limited. This study aims to evaluate the effect of chlorhexidine wax-coated dental floss on dental plaque accumulation and gingival bleeding. Additionally, antibacterial activity and cellular toxicity were also investigated in vitro.

METHODS

Various concentrations of chlorhexidine wax-coated floss (0%, 0.12%, 1%, and 2%) were prepared. The antibacterial activity against Streptococcus mutans was studied using a disc diffusion assay. Cellular toxicity was assessed in L929 cells and human gingival fibroblasts using an MTT assay. To evaluate the effects on plaque accumulation and gingival bleeding, 27 participants were randomly divided into 3 groups: 1) 0% chlorhexidine wax-coated dental floss (control), 2) 0.12% chlorhexidine wax-coated dental floss, and 3) 1% chlorhexidine wax-coated dental floss. All participants were instructed to use the provided dental floss once daily at bedtime for 14 days. Six sites per tooth were evaluated for the Quigley-Hein plaque index and bleeding index (BI) at day 0 (baseline) and day 15. All fully erupted teeth, except the third molars, were examined.

RESULTS

Chlorhexidine-coated floss exhibited antibacterial activity against S. mutans in a dose-dependent manner. In an in-vitro study, a 2% concentration of chlorhexidine in the floss was found to be highly toxic, leading to its exclusion from clinical trials. After 14 days of use, significantly lower levels of BI were observed in the groups using chlorhexidine wax-coated dental floss, compared to the control. Additionally, there was no significant difference in BI between the 0.12% and 1% chlorhexidine wax-coated dental floss groups. However, no significant difference in plaque index was found between the groups using chlorhexidine wax-coated dental floss and the control group.

CONCLUSIONS

This study demonstrated the antibacterial and anti-gingivitis properties of chlorhexidine wax-coated dental floss. Our results showed that using chlorhexidine wax-coated dental floss at a concentration as low as 0.12% could significantly reduce gingival bleeding. However, no additional benefit of chlorhexidine wax-coated dental floss on dental plaque accumulation was found.

Clinical and Microbiological Evaluation of 0.2% Tea Tree Oil Mouthwash in Prevention of Dental Biofilm-Induced Gingivitis

Background: Dental biofilm-induced gingivitis is a prevalent condition caused by dental plaque accumulation. Chlorhexidine mouthwash is a gold standard for plaque control but is associated with adverse effects such as tooth staining and altered taste. This study aimed to evaluate the clinical and antimicrobial effectiveness of 0.2% tea tree oil mouthwash as a natural alternative to 0.2% chlorhexidine mouthwash. Methods: A comparative study was conducted on 60 participants aged 18-60 years, divided into two groups: Group T (tea tree oil) and Group C (chlorhexidine), each comprising 30 participants. Clinical outcomes assessed included Plaque Index (PI), Gingival Index (GI), Bleeding on Probing (BOP), and microbiological Colony Forming Units (CFUs). Parameters were recorded at baseline, 7 days, and 28 days. Results: Group T exhibited significantly lower PI and BOP scores at 7 and 28 days compared to Group C (p < 0.05). Both groups showed comparable reductions in CFU counts, indicating similar antimicrobial efficacy. Importantly, tea tree oil had fewer adverse effects, with no reports of tooth staining or altered taste, unlike chlorhexidine. Conclusion: Tea tree oil mouthwash demonstrated equivalent or superior clinical outcomes compared to chlorhexidine, with fewer side effects. It is a viable and well-tolerated alternative for managing plaque-induced gingivitis, supporting further research into its long-term use and efficacy.

Biocompatibility of irrigation solutions to dental-derived mesenchymal stem cells in regenerative endodontic procedure: a systematic review of in vitro studies

Regenerative endodontic procedures (REPs) offer an alternative to apexification in necrotic immature permanent teeth, promoting continued root development and dentinal wall thickening. Success in REPs requires effective disinfection and the survival of dental-derived mesenchymal stem cells (DMSCs), such as dental pulp stem cells (DPSCs), stem cells from the apical papilla (SCAPs), and periodontal ligament stem cells (PDLSCs). This review investigates the biocompatibility of irrigation solutions, including sodium hypochlorite (NaOCl), ethylenediaminetetraacetic acid (EDTA), and chlorhexidine (CHX), on DMSCs. Following PRISMA guidelines, a comprehensive search was conducted in PubMed, Scopus, Web of Science, Cochrane, and SciELO, with the last update on March 4, 2024. Studies from January 2008 to April 2024 assessing viability, proliferation, migration, differentiation, and mineralization of DMSCs treated with NaOCl, EDTA, and CHX were included. The papers were selected using PICOS criteria and quality was assessed using the PRILE checklist and risk of bias with the Quality Assessment Tool for In Vitro Studies. Of 738 studies identified, 15 met inclusion criteria. The findings suggest that NaOCl and CHX exhibit lower biocompatibility towards DMSCs compared to EDTA. NaOCl and CHX are cytotoxic to DMSCs, while EDTA demonstrates favorable biocompatibility, promoting osteogenic differentiation and mineralization. This highlights potential implications for irrigant selection in regenerative procedures, as appropriate irrigants may enhance cellular survival and improve clinical outcomes.

Expert consensus on the prevention and treatment of enamel demineralization in orthodontic treatment

Enamel demineralization, the formation of white spot lesions, is a common issue in clinical orthodontic treatment. The appearance of white spot lesions not only affects the texture and health of dental hard tissues but also impacts the health and aesthetics of teeth after orthodontic treatment. The prevention, diagnosis, and treatment of white spot lesions that occur throughout the orthodontic treatment process involve multiple dental specialties. This expert consensus will focus on providing guiding opinions on the management and prevention of white spot lesions during orthodontic treatment, advocating for proactive prevention, early detection, timely treatment, scientific follow-up, and multidisciplinary management of white spot lesions throughout the orthodontic process, thereby maintaining the dental health of patients during orthodontic treatment.

Effects of Antimicrobial Agents Used for Dental Treatments: Impacts on the Human Oral Ecosystem and the Resistome

Antimicrobial resistance (AMR) is a major public health concern, especially with regard to bacterial resistance to antibiotics. Dentists are responsible for approximately 10% of all antibiotic prescriptions. In addition, there seems to be a lack of awareness of potential resistance toward antiseptics and biocides such as chlorhexidine digluconate (CHX) or cetylpyridinium chloride (CPC), which are commonly used in dental practice but also included in over-the-counter products. In comparison to the gut microbiome, only a small number of studies have investigated the impact of antibiotics on the oral microbiome. Amoxicillin is a commonly prescribed antibiotic in dentistry, often used in combination with metronidazole. Several studies have addressed its impact on the oral microbiome. Similarly, the effects of ciprofloxacin, clindamycin, cephazolin, and benzylpenicillin have also been examined in various studies. However, due to variations in study designs, it is difficult to compare the effects of antibiotics on the oral microbiota, and conclusions can only be drawn at the phyla level. In contrast, studies on CPC and CHX have also focused on the genus level. The oral resistome mainly contains genes involved in resistance to macrolides, MLSB (macrolide, lincosamide, and streptogramin B), lincosamide and streptogramin A, fluoroquinolone, tetracycline, or penicillin. The oral cavity therefore serves as a reservoir for antibiotic resistance genes (ARGs), which are of crucial importance both for inflammations in the oral cavity and for the treatment of the entire human organism. Therefore, dentists must weigh up the benefits and risks of using antibiotics very carefully.

Remineralization and bacterial inhibition of early enamel caries surfaces by carboxymethyl chitosan lysozyme nanogels loaded with antibacterial drugs

OBJECTIVE

This study aimed to develop dual-functional CMC-LYZ-ACP nanogels. Three different antibacterial substances, tea polyphenols (TPs), silver nitrate (AgNO3), and chlorhexidine (CHX) are then combined to form three dual-functional CMC-LYZ-ACP nanogels for remineralization and antibacterial purposes.

METHODS

An in vitro model of Streptococcus mutans biofilm was established to analyze the inhibitory effect of the antibacterial-remineralizing dual-functional nanogels on the biofilm. And the nanogels were applied to the surface of demineralized enamel to assess their remineralization efficacy.

RESULTS

The three remineralization-antibacterial dual-functional CMC-LYZ-ACP nanogels exhibited stable particle sizes within 200 nm and were all negatively charged nanospherical structures. They demonstrated significant inhibitory effects against Streptococcus mutans and achieved good remineralization outcomes both in vitro and in vivo.

CONCLUSION

The incorporation of the three antibacterial agents (AgNO3, TPs, CHX) endowed the CMC-LYZ-ACP nanogels with excellent antibacterial properties, inhibiting the growth of plaque biofilms while maintaining their potent remineralization capabilities.

CLINICAL SIGNIFICANCE

Remineralizing demineralized enamel while inhibiting biofilm adhesion and formation of caries-inducing bacteria can block caries and provide new strategies for early enamel caries treatment.

The effect of an antioxidant gel compared to chlorhexidine during the soft tissue healing process: An animal study

BACKGROUND

Prolonged inflammation and oxidative stress can impede healing. To enhance healing efficiency, many solutions have been employed. This is an in vivo study comparing chlorhexidine (CHX) to a commercial antioxidant gel (AO).

METHODS

Envelope flaps were created in the lower incisor gingival region of 60 Sprague-Dawley rats, and acellular dermal matrix (ADM) was inserted. Animals were randomly assigned to postsurgical treatment application of AO gel or 0.12% CHX twice daily. A control group received no postsurgical treatment. Data collected (before surgery, 24 h, and 72 h) included surgical images, tissue samples, and weights. Blinded scorers assessed images using a wound healing scale. Real-time polymerase chain reaction (RT-PCR) was used for gene expression of tumor necrosis factor-alpha (TNFα), interleukin-1 (IL-1), myeloperoxidase (MPO), and superoxide dismutase (SOD).

RESULTS

The AO group scored higher than the CHX and control groups in clinical evaluation (p < 0.05). At 24 h, TNFα expression was upregulated in the AO group compared to CHX (p = 0.027) and controls (p = 0.018). The AO group had significantly higher expression of antioxidant enzyme (SOD) at 24 h compared to CHX (p = 0.021). All animals lost weight in the first 24 h. Animals treated with AO or CHX regained more weight at 72 h than control animals (p = 0.034 and 0.003, respectively).

CONCLUSION

Animals treated with AO healed faster. AO led to earlier upregulation of TNFα and antioxidant enzyme SOD. We hypothesized that AO promoted an earlier inflammatory process while counteracting oxidative stress by increasing antioxidant responses via SOD.

Novel strategy of S. mutans gcrR gene over-expression plus antibacterial dimethylaminohexadecyl methacrylate suppresses biofilm acids and reduces dental caries in rats

OBJECTIVE

Streptococcus mutans (S. mutans) is a major contributor to dental caries, with its ability to synthesize extracellular polysaccharides (EPS) and biofilms. The gcrR gene is a regulator of EPS synthesis and biofilm formation. The objectives of this study were to investigate a novel strategy of combining gcrR gene over-expression with dimethylaminohexadecyl methacrylate (DMAHDM), and to determine their in vivo efficacy in reducing caries in rats for the first time.

METHODS

Two types of S. mutans were tested: Parent S. mutans; and gcrR gene over-expressed S. mutans (gcrR OE S. mutans). Bacterial minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were measured with DMAHDM and chlorhexidine (CHX). Biofilm biomass, polysaccharide, lactic acid production, live/dead staining, colony-forming units (CFUs), and metabolic activity (MTT) were evaluated. A Sprague-Dawley rat model was used with parent S. mutans and gcrR OE S. mutans colonization to determine caries-inhibition in vivo.

RESULTS

Drug-susceptibility of gcrR OE S. mutans to DMAHDM or CHX was 2-fold higher than that of parent S. mutans. DMAHDM reduced biofilm CFU by 3-4 logs. Importantly, the combined gcrR OE S. mutans+ DMAHDM dual strategy reduced biofilm CFU by 5 logs. In the rat model, the parent S. mutans group had a higher cariogenicity in dentinal (Dm) and extensive dentinal (Dx) regions. The DMAHDM + gcrR OE group reduced the Dm and Dx caries to only 20 % and 0 %, those of parent S. mutans + PBS control group (p < 0.05). The total caries severity of gcrR OE + DMAHDM group was decreased to 51 % that of parent S. mutans control (p < 0.05).

SIGNIFICANCE

The strategy of combining S. mutans gcrR over-expression with antibacterial monomer reducing biofilm acids by 97 %, and reduced in vivo total caries in rats by 48 %. The gcrR over-expression + DMAHDM strategy is promising for a wide range of dental applications to inhibit caries and protect tooth structures.

Synergistic Effect of Metronidazole and Chlorhexidine against Porphyromonas gingivalis Growth: An In Vitro Study

Aim: To evaluate the potential synergistic activity of metronidazole (MTZ) and chlorhexidine (CHX) against Porphyromonas. gingivalis (P. gingivalis) growth. Methods: Antimicrobial susceptibility tests of P. gingivalis to MTZ and CHX were performed on in vitro serial 2-fold dilutions of MTZ (from 1 mg/mL to 0.015 mg/mL) and CHX (from 1 mg/mL to 0.03 mg/mL) in thioglycollate medium broth in a 96-well plate. The turbidity of each sample was analyzed by absorbance spectrophotometry at 450 nm wavelengths by using an enzyme-linked immunosorbent assay (ELISA) reader. The MIC50 (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) were assessed. To investigate the potential synergism between MTZ and CHX, bacterial cells were treated with MTZ or CHX, as described above, either alone or in combination. Results: The MIC50 of MTZ was 0.03 mg/mL while that of CHX ranged from 0.12 to 0.06 mg/mL. MTZ and CHX exerted a significant inhibitory effect on P. gingivalis growth in a dose-dependent manner. MTZ at a low and ineffective concentration of 0.015 mg/mL, associated with a suboptimal concentration of CHX (0.03 mg/mL), exhibited a significant synergistic inhibitory effect on bacterial growth (50% inhibition vs. control) (p < 0.001), and the effect was more remarkable with 0.06 mg/mL CHX (75% inhibition vs. control). Conclusions: CHX and MTZ showed a significant synergistic effect against P. gingivalis growth. A non-effective concentration of MTZ (0.015 mg/mL) combined with suboptimal concentrations of CHX (0.03 mg/mL and 0.06 mg/mL) were related to a 50% growth in the inhibition and 99.99% death of P. gingivalis, respectively. The applicability of the clinical use of these concentrations should be tested in randomized controlled trials.

Singlet oxygen detection in vivo is hindered by nonspecific SOSG staining

Singlet oxygen is considered an important cell damaging agent due to its propensity to react with organic compounds. This drives the interest in developing methods for determination of 1O2. Simplicity of application and high sensitivity makes fluorescent probes a popular choice for in vivo 1O2 detection. Despite its proclaimed cell-impermeability, the commercially available Singlet Oxygen Sensor Green (SOSG) is widely applied to support assertions of 1O2 involvement in cell and tissue damage. Our investigation, however, demonstrate that different microbial species and cancer cells become fluorescent when exposed to SOSG under conditions which exclude generation of 1O2. Cells, permeabilized with chlorhexidine or by heat exposure under anaerobic conditions, exhibited SOSG fluorescence. Permeabilized cells could be stained with SOSG even 24 h post-permeabilization. Since SOSG is cell impermeable, the main factor that led to fluorescent staining was plasma membrane damage. Spectral analyses of different batches of SOSG revealed that SOSG endoperoxide (SOSG-EP) did not increase even after prolonged storage under the recommended conditions. The commercial preparations of SOSG, however, were not SOSG-EP free, which can produce erroneous results when SOSG staining is used as a proof of singlet oxygen production in vivo.

Clinical and microbial evaluation of mouthwash containing Achyranthes aspera and Trachyspermum ammi: A randomized controlled non-inferiority trial

Objectives

Achyranthes aspera (Apamarga) and Trachyspermum ammi (Ajwain) have been used in many clinical conditions, and it displays valuable properties as an alternative to Chlorhexidine (CHX) in the management of gingivitis. Therefore, this study aims to assess the effect of Achyranthes aspera and Trachyspermum ammi (AA + TA) based herbal mouthwash, 0.2 % CHX, and placebo mouthwash on gingival health, plaque control and antibacterial activity against specific periodontal pathogens (Porphyromonas gingivalis and Tannerella forsythia) using quantitative real-time PCR (RT-PCR).

Methods

This was a randomized controlled non-inferiority trial involving 108 children with plaque-induced gingivitis who were randomly assigned to three groups of 36 children each: Group A, AA + TA mouthwash; Group B, CHX mouthwash; and Group C, placebo mouthwash. Gingival index and plaque index were recorded at baseline, 7th and 21st day. RT-PCR was employed to determine the bacterial counts of each plaque sample at baseline and after 21 days.

Results

All three groups exhibited a gradual and significant reduction in both gingival and plaque scores from baseline to days 7 and 21. However, the placebo group did not demonstrate a significant difference in scores between days 7 and 21. Furthermore, a significant reduction in bacterial counts of P. gingivalis and T. forsythia was observed in the groups receiving CHX and AA + TA mouthwash after 21 days of intervention compared to the placebo group.

Conclusion

AA + TA mouthwash demonstrated non-inferiority in anti-gingivitis and anti-plaque properties compared to CHX, suggesting its potential suitability as an alternative to CHX when used in conjunction with mechanical plaque control measures.

Antimicrobial Activity of Antibacterial Sutures in Oral Surgery: A Scoping Review

OBJECTIVE

The aim of this scoping review was to explore and synthesise the current evidence on the antimicrobial activity of antibacterial suture materials used in oral surgery.

METHODS

The review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Extension for Scoping Reviews. A bibliographic search was carried out in the PubMed and Scopus databases to retrieve all human clinical studies that investigated the antimicrobial efficacy of antibacterial-coated sutures used in oral surgery. Included studies were screened and extracted independently by 2 examiners. Data were tabulated and qualitatively described.

RESULTS

The search initially returned 150 articles and resulted in 5 included studies after the duplicates' removal and the full-text screening. Selected studies were published from 2014 to 2019. Three studies (60%) were randomised clinical trials, whilst the remaining studies did not report information on randomisation. The antimicrobial agents for coated sutures included triclosan and chlorhexidine. In almost all the studies, antibacterial-coated sutures exhibited lower bacterial retention compared to those without coating.

CONCLUSIONS

Within limitations, the antimicrobial-coated sutures employed in oral surgery exhibited good results in terms of their microbicidal activity when compared with sutures that were not coated. Considering the high variability and confounding factors identified in the included studies, more high-quality research is needed to confirm these results. Antimicrobial-coated sutures could represent a promising and clinically valid strategy to reduce microbial colonisation in oral surgery. The reduced bacterial adherence is likely to improve the clinical success of the surgical procedures. Yet, the cost-benefit ratio of antimicrobial-coated sutures should be assessed in larger clinical trials to confirm their efficacy over conventional noncoated sutures.

Chlorhexidine digluconate mouthwash alters the oral microbial composition and affects the prevalence of antimicrobial resistance genes

Introduction

Chlorhexidine (CHX) is a commonly used antiseptic in situations of limited oral hygiene ability such as after periodontal surgery. However, CHX is also considered as a possible factor in the emergence of cross-resistance to antibiotics. The aim of this study was to analyze the changes in the oral microbiota and the prevalence of antimicrobial resistance genes (ARGs) due to CHX treatment.

Materials and methods

We analyzed the oral metagenome of 20 patients who applied a 0.2% CHX mouthwash twice daily for 4 weeks following periodontal surgical procedures. Saliva and supragingival plaque samples were examined before, directly after 4 weeks, and another 4 weeks after discontinuing the CHX treatment.

Results

Alpha-diversity decreased significantly with CHX use. The Bray-Curtis dissimilarity increased in both sample sites and mainly streptococci showed a higher relative abundance after CHX treatment. Although no significant changes of ARGs could be detected, an increase in prevalence was found for genes that encode for tetracycline efflux pumps.

Conclusion

CHX treatment appears to promote a caries-associated bacterial community and the emergence of tetracycline resistance genes. Future research should focus on CHX-related changes in the microbial community and whether the discovered tetracycline resistance genes promote resistance to CHX.

Formulation and assessment of biological properties of garcinia indica fruit extract mouthrinse as an adjunct to oral hygiene regimen: an in vitro analysis

The prevalence of gingivitis is substantial within the general population, necessitating rigorous oral hygiene maintenance.

OBJECTIVE

This study assessed a Garcinia indica (GI) fruit extract-based mouthrinse, comparing it to a 0.1% turmeric mouthrinse and a 0.2% Chlorhexidine (CHX) mouthrinse. The evaluation encompassed substantivity, staining potential, antimicrobial efficacy and cytocompatibility.

METHODOLOGY

The study employed 182 tooth sections. For antimicrobial analysis, 64 extracted human teeth coated with a polymicrobial biofilm were divided into four groups, each receiving an experimental mouthrinse or serving as a control group with distilled water. Microbial reduction was assessed through colony forming units (CFU). Substantivity was evaluated on 54 human tooth sections using a UV spectrophotometer, while staining potential was examined on 64 tooth sections. Cytocompatibility was tested using colorimetric assay to determine non-toxic levels of 0.2% GI fruit extract, 0.1% Turmeric, and 0.2% CHX.

RESULTS

Data were analysed with one-way ANOVA (α=0.05). Cell viability was highly significant (p<0.001) in the 0.2% GI group (64.1±0.29) compared to 0.1% Turmeric (40.2±0.34) and 0.2% CHX (10.95±1.40). For antimicrobial activity, both 0.2% GI (20.18±4.81) and 0.2% CHX (28.22±5.41) exhibited no significant difference (P>0.05) at end of 12 hours. However, 0.1% Turmeric showed minimal CFU reduction (P<0.001). Substantivity results at 360 minutes indicated statistically significant higher mean release rate in 0.1%Turmeric (12.47±5.84 ) when compared to 0.2% GI (5.02±3.04) and 0.2% CHX (4.13±2.25) (p<0.001). The overall discoloration changes (∆E) were more prominent in the 0.2% CHX group (18.65±8.3) compared to 0.2% GI (7.61±2.4) and 0.1% Turmeric (7.32±4.9) (P<0.001).

CONCLUSION

This study supports 0.2% GI and 0.1% Turmeric mouth rinses as potential natural alternatives to chemical mouth rinses. These findings highlight viability of these natural supplements in oral healthcare.

Topical oxygen therapy as a novel strategy to promote wound healing and control the bacteria in implantology, oral surgery and periodontology: A review

Globally, oral infections and inflammatory lesions persist as substantial public health concerns, necessitating the introduction of novel oral treatment protocols. Oral diseases are linked to various causative factors, with dental plaque/biofilm resulting from inadequate hygiene practices playing a predominant role. The strategic implementation of novel topical therapies holds promise for effectively controlling the biofilms, addressing oral infections and promoting enhanced oral wound healing. This review aims to providing a comprehensive overview of the available evidence pertaining to the potential efficacy of topical oxygen and lactoferrin-releasing biomaterials, exemplified by the blue®m formula, as novel oral care interventions within the scope of contemporary implantology, oral surgery and periodontology.

Exploring the role of flavonoids in caries-affected dentin adhesion: A comprehensive scoping review

OBJECTIVES

The aim of this scoping review was to evaluate the available scientific evidence regarding the use of flavonoids in the treatment of caries-affected dentin focusing on bonding to dentin.

METHODS

A comprehensive literature search was performed in five databases from March 2022 and updated in April 2023: PubMed, EMBASE, Scopus, Web of Science, and Scielo. Additionally, the references of included studies were manually searched. Gray literature was excluded from the review.

STUDY SELECTION

Inclusion criteria included in vitro, in situ, and in vivo studies (animal or human) published in English. Abstracts, reviews, case reports, book chapters, doctoral dissertations, guidelines, and studies using pure plant extracts were excluded. Data collected from the selected studies were summarized and subjected to narrative and descriptive analysis. Out of the 91 studies identified, only 16 studies met the inclusion criteria.

RESULTS

The review analyzed eight different flavonoids (hesperidin, galardin, proanthocyanidin, genipin, quercetin, naringin, epigallocatechin-3-gallate, and other catechins subtypes) used as pretreatment or loaded into adhesive systems, primers, and phosphoric acid. The use of flavonoids improved the mechanical properties of the materials and modified the biological properties of the dentin, reducing collagen loss by the inhibition of proteolytic activity of matrix metalloproteinases (MMPs).

CONCLUSIONS

Based on the findings of this scoping review, it can be concluded that the use of flavonoids as pretreatment or incorporation into dental materials preserves collagen in the hybrid layer, inhibiting the MMPs activities, modifying the collagen fibrils of the dentin matrix and improving the mechanical properties of the dental adhesive systems. Therefore, it represents a promising approach for promoting dentin biomodification. This can result in more stable bonding of adhesive restorations to caries-affected dentin.

Hyperpure chlorine dioxide versus chlorhexidine in intra-oral halitosis (ODOR trial) - protocol of a double-blinded, double-arm, parallel non-inferiority pilot randomized controlled trial

INTRODUCTION

Intra-oral halitosis (IOH) is the most common type of bad breath; its consequences impair quality of life. However, evidence-based treatment protocols and guidelines are lacking. Our aim is to investigate the effectiveness of chlorine dioxide as an applicable complementary treatment modality in IOH after tongue cleaning.

METHODS AND ANALYSIS

The ODOR trial will be a single-center, double-blinded, parallel-group, double-armed pilot randomized controlled trial with a non-inferiority design. The efficacy of hyperpure chlorine dioxide will be compared to chlorhexidine mouthwash. We plan to investigate the short-term effects of the intervention over a 3-h period. The primary endpoint will be changes in organoleptic test scores. At the end of the pilot investigation of the first 30 patients each, sample size calculation will be performed. If feasible, the investigators will continue the study by enrolling more patients.

TRIAL REGISTRATION

The trial has been registered at ClinicalTrials.gov (NCT06219226).

Preparation and Characterization of Ginseng Gel and In Vivo Evaluation of Its Clinical Efficacy in Generalized Chronic Gingivitis Patients

Aim The aim of the present study was to prepare and characterize ginseng gel and then to evaluate its clinical efficacy in terms of plaque index (PI), gingival index (GI) among generalized chronic gingivitis patients. Materials and methods Ginseng gel was prepared using 250 g of ginseng powder. The antimicrobial activity of prepared ginseng gel and chlorhexidine gel was checked at various concentrations (25, 50, 75, 100, 125, 150, 175, 200, 225, 250 and 275 µg) against anaerobic organisms to find the concentration with maximum antimicrobial activity. The concentration with highest antimicrobial activity was subjected to in vivo analysis. A total of 30 generalized chronic gingivitis patients were subjected to scaling and then divided into two groups for intraoral gel application - Group I (ginseng gel) and Group II (chlorhexidine gel) for one month. The clinical parameters PI, GI were measured at baseline (pre scaling) and one month (post scaling) comparing ginseng gel and chlorhexidine gel (Hexigel - chlorhexidine gluconate 1.0% w/w). Independent t test and paired t test were done for statistical analysis. Results At 275 µg, ginseng gel showed highest antibacterial action against anaerobic oral microorganisms. In Group I, the reduction in PI from baseline was (2.52±0.02) to follow up after one month (0.75±0.05), GI from baseline (2.2±0.35) to follow up after one month (0.9±0.02). In Group II, the reduction in PI from baseline was (2.54±0.01) to follow up after one month (0.79±0.02), GI from baseline (2.1±0.42) to follow up after one month (0.8±0.01). Conclusion Ginseng gel showed equal clinical efficacy to chlorhexidine gel in terms of PI and GI. Though chlorhexidine was effective in lower concentrations, it has considerable adverse effects such as taste alteration. Hence it is better to encourage the use of herbal-based products for the management of gingivitis to prevent side effects of synthetic preparations.

Acquired Pellicle and Biofilm Engineering by Rinsing with Hemoglobin Solution

INTRODUCTION

The identification of acid-resistant proteins, including hemoglobin (Hb), within the acquired enamel pellicle (AEP) led to the proposition of the "acquired pellicle engineering" concept, which involves the modification of the AEP by incorporating specific proteins, presenting a novel strategy to prevent dental demineralization.

OBJECTIVE

Combining in vivo and in vitro proof-of-concept protocols, we sought to reveal the impact of AEP engineering with Hb protein on the biofilm microbiome and enamel demineralization.

METHODS

In the in vivo studies, 10 volunteers, in 2 independent experiments, rinsed (10 mL,1 min) with deionized water-negative control or 1.0 mg/mL Hb. The AEP and biofilm formed along 2 or 3 h, respectively, were collected. AEP was analyzed by quantitative shotgun-label-free proteomics and biofilm by 16S-rRNA next-generation sequencing (NGS). In in vitro study, a microcosm biofilm protocol was employed. Seventy-two bovine enamel specimens were treated with (1) phosphate-buffered solution (PBS), (2) 0.12% chlorhexidine, (3) 500 ppm NaF, (4) 1.0 mg/mL Hb, (5) 2.0 mg/mL Hb, and (6) 4.0 mg/mL Hb. The biofilm was cultivated for 5 days. Resazurin, colony forming units (CFU), and transversal microradiography were performed.

RESULTS

Proteomics and NGS analysis revealed that Hb increased proteins with antioxidant, antimicrobial, acid-resistance, hydroxyapatite-affinity, calcium-binding properties and showed a reduction in oral pathogenic bacteria. In vitro experiments demonstrated that the lowest Hb concentration was the most effective in reducing bacterial activity, CFU, and enamel demineralization compared to PBS.

CONCLUSION

These findings suggest that Hb could be incorporated into anticaries dental products to modify the oral microbiome and control caries, highlighting its potential for AEP and biofilm microbiome engineering.

Pine-Oil-Derived Sodium Resinate Inhibits Growth and Acid Production of Streptococcus mutans In Vitro

S. mutans is a key pathogen in dental caries initiation and progression. It promotes oral biofilm dysbiosis and biofilm acidification. Sodium resinate is a salt of pine-oil-derived resin which has antimicrobial properties. Pine-oil-derived resin consists of terpenes, diterpenes, and abietic acids. The aim of this study was to determine the effects of pine (Pinus sylvestris) oil resinate (RS) on growth and acid production of cariogenic S. mutans strains in planktonic form and biofilm. The S. mutans type strain NCTC10449 and clinical isolate CI2366 were grown on 96-well plates for testing of RS effects on growth and biofilm formation, and on plates with integrated pH-sensitive optical ensors for real-time measurements of the effects of RS on bacterial acid production. We found that even short-time exposure to RS inhibits the growth and acid production of S. mutans in the planktonic phase and biofilms. In addition, RS was able to penetrate the biofilm matrix and reduce acid production inside S. mutans biofilm. RS thus shows potential as a novel antibacterial agent against cariogenic bacteria in biofilm.

Use of over-the-counter mouthwashes as an additional measure in individual oral prophylaxis on adults with plaque-induced gingivitis: a double-blind, parallel, randomized controlled trial

BACKGROUND

Plaque-induced gingivitis is a chronic inflammatory condition characterized by complete reversibility of tissue damage once the periodontal biofilm has been disorganised. The aim of this study was to evaluate the efficacy of two commercially available mouthwashes (MWs) versus a chlorhexidine (CHX) 0.12% MW in reducing gingival bleeding (GB) in adults with plaque-induced gingivitis.

METHODS

The present study was a double-blind, parallel, randomized controlled trial involving 6492 gingival sites (i.e. 39 subjects × 28 teeth × 6 sites/tooth) aged 18-75 years. During a 2-week period, subjects were randomized to receive MWs: a control CHX 0.12% MW (group C, 1818 sites); a MW test containing CHX 0.09% + Citrox®/P complex (group CX, 2628 sites); a MW test based on natural compounds (group P, 2016 sites). GB was assessed at the inclusion visit (T0) and after 2 weeks of MW use (T1). Analyses of GB were compared between groups and then restricted to subjects with bleeding sites between 10 and 30% (moderate gingivitis) or ≥ 30% (severe gingivitis) at T0. Pairwise comparisons were made between groups and logistic regression was used to identify correlates of GB (T1).

RESULTS

For total bleeding site analysis, GB reduction between T0 and T1 ranged from 23% (C), 26% (CX) and 36% (P), respectively (all p < 0.05). Multiple comparison between groups showed that group C was significantly less effective (p < 0.05) than groups CX and P. Splitting the analysis, in patients with severe gingivitis (≥ 30% bleeding sites at T0), all MWs had a positive effect on GB with a reduction at T1 of 36% (C), 33% (CX) and 42% (P), respectively. While GB reduction between T0 and T1, was significant for all groups, the comparison among groups showed no significant difference between group C and CX, whereas the improvement was significant for group P. On the other hand, in adults with moderate gingivitis (< 30% bleeding sites at T0), only CX and P had a positive effect on GB reduction at T1(9% in CX and 2% in P, respectively), although the differences between the three groups were not significant.

CONCLUSION

The daily use of MWs with natural components (groups P and CX) for 2 weeks should be considered positively as an adjunct to individual oral prophylaxis to reduce GB compared to the control MW containing CHX 0.12% (group C) in healthy adults with plaque-induced gingivitis. For subjects with severe gingivitis, it is advisable to first use natural MW (P) and then MW based on CHX 0.09% with natural components (CX), compared to MW with CHX 0.12% (C). For adults with moderate gingivitis, P and CX can be advisable, even if no definitive recommendations can be drawn.

TRIAL REGISTRATION

ACTRN12622000215729, 07/02/2022.

Clinical Efficacy of Different Concentrations of Povidone Iodine in the Management of Peri-Implant Mucositis

Mechanical plaque control is the first line of management of peri-implant diseases. Povidone iodine is one of the broad spectrum and potent antiseptics available at various concentrations. The aim of the study was to assess and compare the efficacy of various concentrations of povidone iodine in the management of peri-implant mucositis. In the present double blinded, parallel designed, randomized clinical trial, a total of 60 patients with peri-implant mucositis (20 participants in each group [Group 1 (povidone iodine 0.1%), Group 2 (povidone iodine 2%) and Group 3 (povidone iodine 010%)] were enrolled. Scaling and root planing was done and then the peri-implant sulcus was irrigated with respective irrigant and repeated once in a week for 4 weeks. Loe and Silness Gingival Index (GI) and Mombelli Modified sulcular bleeding index (BI) were recorded at baseline and after a month and compared. Statistical analysis was done using One-way ANOVA and Tukey's HSD post hoc test. A statistically significant difference (P = 0.000) observed between the three concentrations when compared after 1 month. Also, a statistically significant difference between Group 1 and Group 3 and Group 2 and Group 3 was observed in terms of post GI (P = 0.000) and post BI (P = 0.000) but statistically no significant difference was observed between Group 1 and Group 2 in terms of post GI (P = 0.171) and post BI (P = 0.338). The 2% and 10% povidone iodine showed significant improvement in gingival index and bleeding index and hence it could be an effective adjunct to scaling and root planing in the management of peri-implant mucositis.

Physical-chemical influences and cell behavior of natural compounds on titanium dental surfaces

The present study evaluated the influence of carvacrol, terpinene-4-ol, and chlorhexidine on the physical-chemical properties of titanium surfaces, cell viability, proliferation, adhesion, and spreading of fibroblasts and osteoblasts in vitro. Titanium surfaces (Ti) were treated with Carvacrol (Cvc), Terpinen-4-ol (T4ol), Chlorhexidine (CHX), DMSO, and ultrapure water (Control group). Physical-chemical modifications were evaluated by surface wettability, the surface free energy (SFE) calculated from the contact angle values using the Owens-Wendt-Rabel-Kaeble (OWRK) equation, scanning electron microscopy (SEM) and energy dispersive spectrometry probe (EDS) system. Cells were seeded onto Ti-treated surfaces and incubated for 24 h and 72 h, then evaluated by Alamar blue assay and fluorescence microscopy. Surfaces treated with Cvc and T4ol showed the presence of Na, O, and Cl. All surfaces showed hydrophilic characteristics and SFE values between 5.5 mN/m and 3.4 mN/m. On the other hand, EDS peaks demonstrated the presence of O and Cl after CHX treatment. A reduction of cell viability and adhesion was noted on titanium surfaces treated with CHX after 24 and 72h. In conclusion, the results indicate that the decontamination with Cvc and T4ol on Ti surfaces does not alter the surface proprieties and allows an adequate interaction with cells involved in the re-osseointegration process such as fibroblasts and osteoblasts.

Comparison of global decolonization efficacy with mupirocin nasal drop and chlorhexidine mouthwash in acute leukemia patients: randomized clinical trial

PURPOSE

Neutropenic fever remains a major complication in acute leukemia. Decolonization is assumed as a promising intervention for eradicating causative agents of infection.

METHODS

In this randomized clinical trial, 96 patients with acute leukemia were assigned randomly to mupirocin nasal drop 2% (n = 32), chlorhexidine mouthwash 0.2% (n = 33), and control group (n = 31). In control group, patients did not receive any medication for decolonization. All patients received treatment for 5 days (2 days prior to chemotherapy until 3 days after chemotherapy). Pharynx and nasal swabs were taken prior to the intervention and at the end of decolonization period in all groups. Antibiotic susceptibility testing was performed by the disc diffusion method in order to identify bacterial isolates.

RESULTS

Bacterial recovery of both nasal and pharynx swabs was observed after global decolonization with mupirocin nasal drop. Decolonization with mupirocin significantly eradicated Coagulase-negative staphylococci (CONS) in both nasal and pharynx swabs (p-value = 0.000). Moreover, mupirocin decreased Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) species. Chlorhexidine mouthwash significantly eradicated CONS in pharynx swabs (p-value = 0.000). In addition, both decolonization strategies decreased both antibiotic use and frequency of fever in leukemic patients.

CONCLUSION

Global decolonization with mupirocin nasal drop not only eradicates both nasal and pharynx microorganisms, but also reduces antibiotic requirement and frequency of fever in patients with acute leukemia. The protocol of the present study was approved on December 2016 (registry number: IRCT20160310026998N6).

Factorial design of in situ gelling two-compartment systems containing chlorhexidine for the treatment of periodontitis

Periodontitis is one of the most widespread bacterial infectious oral diseases that affects a significant percentage of the population worldwide. Different bacterial strains are responsible for the chronic inflammation and subgingival plaque that could be effectively treated with prolonged exposure to therapeutic levels of antibiotics and antiseptics in the periodontal pockets. Medicated in situ gels of chlorhexidine (CHX), for extended drug release and long-lasting antiseptic effect in the targeted cavities, were prepared in a two-compartment system. One compartment was loaded with sodium alginate solution while other was filled with CHX and calcium solution. The mixing of the solutions during the application resulted in gelation. Two 33 full factorial designs were applied in this study in order to optimize the gel formulation. Initially, the effects of concentration of gelling agent, crosslinker, and pH of the system on the dependent variables such as gel formation and structure characteristics were investigated. Then, the concentration of the crosslinker was optimized. Afterwards, the effect of gelling agent, loading of the drug, and pH of the gel system were correlated with the gel characteristics through another factorial design. Optimized formulations were tested for mucoadhesion, in vitro drug release, and microbiological investigation. Based on the results of the factorial design, mucoadhesiveness, antimicrobial investigation, and drug release, a 4 % alginate composition can be considered optimal. Overall, the optimized in situ periodontal gel was found to be effective with prolonged retention time and desirable outcomes.

Mouthwash Effects on the Oral Microbiome: Are They Good, Bad, or Balanced?

This narrative review describes the oral microbiome, and its role in oral health and disease, before considering the impact of commonly used over-the-counter (OTC) mouthwashes on oral bacteria, viruses, bacteriophages, and fungi that make up these microbial communities in different niches of the mouth. Whilst certain mouthwashes have proven antimicrobial actions and clinical effectiveness supported by robust evidence, this review reports more recent metagenomics evidence, suggesting that mouthwashes such as chlorhexidine may cause "dysbiosis," whereby certain species of bacteria are killed, leaving others, sometimes unwanted, to predominate. There is little known about the effects of mouthwashes on fungi and viruses in the context of the oral microbiome (virome) in vivo, despite evidence that they "kill" certain viral pathogens ex vivo. Evidence for mouthwashes, much like antibiotics, is also emerging with regards to antimicrobial resistance, and this should further be considered in the context of their widespread use by clinicians and patients. Therefore, considering the potential of currently available OTC mouthwashes to alter the oral microbiome, this article finally proposes that the ideal mouthwash, whilst combatting oral disease, should "balance" antimicrobial communities, especially those associated with health. Which antimicrobial mouthwash best fits this ideal remains uncertain.

Assessment of potential antimicrobial activity of Ocimum basilicum extract and chlorhexidine against Socransky's complex pathogens of oral cavity: An in vitro study

Background and Objective

Periodontitis is a multifactorial disease initiated by periodontal pathogens and progresses further in destruction of periodontium. Hence, the objective of this study was to test the efficacy of Ocimum basilicum seeds extract on periodontal pathogens.

Materials and Methods

O. basilicum seeds were authenticated from a recognized taxonomist. They were coarsely powdered; ethanol-based extract preparation was done by the Soxhlet method and aqueous-based extract by hot infusion procedure. Extracts so obtained were assessed for minimum inhibitory concentration, minimum bactericidal concentration, zone of inhibition, and time-kill assay of O. basilicum seeds extract on periodontal pathogens, and comparatively evaluated the effectiveness against 0.12% chlorhexidine (CHX) gluconate in triplicates. Kruskal-Wallis Test was employed wherein the statistical significance was set at P ≤ 0.05.

Results

The concentration of O. basilicum ethanolic extract against periodontal pathogens was determined to be 10 mg/ml, whereas 4.7 mg/ml of aqueous extract was proven effective against periodontal pathogens. Similarly, aqueous extract of O. basilicum developed a wider zone against periodontal pathogens compared to ethanol-based O. basilicum extract. Statistically significant difference found in the effectiveness between both extract and CHX.

Conclusion

The antibacterial activity was evident in both the extracts of O. basilicum against anaerobic periodontal pathogens. However, it was more pronounced in aqueous extract, but lower compared to CHX.

Preparation for mice spaceflight: Indications for training C57BL/6J mice to adapt to microgravity effect with three-dimensional clinostat on the ground

Like astronauts, animals need to undergo training and screening before entering space. At present, pre-launch training for mice mainly focuses on adaptation to habitat system. Training for the weightless environment of space in mice has not received much attention. Three-dimensional (3D) clinostat is a method to simulate the effects of microgravity on Earth. However, few studies have used a 3D clinostat apparatus to simulate the effects of microgravity on animal models. Therefore, we conducted a study to evaluate the feasibility and effects of long-term treatment with three-dimensional clinostat in C57BL/6 J mice. Thirty 8-week-old male C57BL/6 J mice were randomly assigned to three groups: mice in individually ventilated cages (MC group, n = 6), mice in survival boxes (SB group, n = 12), and mice in survival boxes receiving 3D clinostat treatment (CS group, n = 12). The mice showed good tolerance after 12 weeks of alternate day training. To evaluate the biological effects of simulated microgravity, the changes in serum metabolites were monitored using untargeted metabolomics, whereas bone loss was assessed using microcomputed tomography of the left femur. Compared with the metabolome of the SB group, the metabolome of the CS group showed significant differences during the first three weeks and the last three weeks. The KEGG pathways in the late stages were mainly related to the nervous system, indicating the influence of long-term microgravity on the central nervous system. Besides, a marked reduction in the trabecular number (P < 0.05) and an increasing trend of trabecular spacing (P < 0.1) were observed to occur in a time-dependent manner in the CS group compared with the SB group. These results showed that mice tolerated well in a 3D clinostat and may provide a new strategy in pre-launch training for mice and conducting relevant ground-based modeling experiments.

Chlorhexidine gel topical application ameliorates inflammatory bone loss in experimental periodontitis

OBJECTIVES

This study aimed to evaluate the impact of chlorhexidine (CHX) gel on inflammation-induced periodontal tissue destruction, osteoclastogenesis, subgingival microbiota, and on the modulation of the RANKL/OPG as well as inflammatory mediators during bone remodeling in vivo.

MATERIALS AND METHODS

Ligation- and LPS injection-induced experimental periodontitis were created to investigate the effect of topical application of CHX gel in vivo. Alveolar bone loss, osteoclast number and gingival inflammation was evaluated by micro-CT, histological, immunohistochemistry and biochemical analysis. The composition of the subgingival microbiota was characterized by 16S rRNA gene sequencing.

RESULTS

Data shows significant decreases in the alveolar bone destruction in rats from ligation-plus-CHX gel group compared to ligation group. In addition, significant decreases in the number of osteoclasts on bone surface and the protein level of receptor activator of nuclear factor κB ligand (RANKL) in gingival tissue were observed in rats from ligation-plus-CHX gel group. Moreover, data shows significantly decreased inflammatory cell infiltration and decreased expression of cyclooxygenase (COX-2) and inducible NO synthase (iNOS) in gingival tissue from ligation-plus-CHX gel group versus ligation group. Assessment of the subgingival microbiota revealed changes in rats with CHX gel application treatment.

CONCLUSION

HX gel presents protective effect on gingival tissue inflammation, osteoclastogenesis, RANKL/OPG expression, inflammatory mediators, and alveolar bone loss in vivo, which may have a translational impact on the adjunctive use in the management of inflammation-induced alveolar bone loss.

Emerging evidence-based innovative approaches to control catheter-associated urinary tract infection: a review

Healthcare settings have dramatically advanced the latest medical devices, such as urinary catheters (UC) for infection, prevention, and control (IPC). The continuous or intermittent flow of a warm and conducive (urine) medium in the medical device, the urinary catheter, promotes the formation of biofilms and encrustations, thereby leading to the incidence of CAUTI. Additionally, the absence of an innate immune host response in and around the lumen of the catheter reduces microbial phagocytosis and drug action. Hence, the review comprehensively overviews the challenges posed by CAUTI and associated risks in patients' morbidity and mortality. Also, detailed, up-to-date information on the various strategies that blended/tailored the surface properties of UC to have anti-fouling, biocidal, and anti-adhesive properties to provide an outlook on how they can be better managed with futuristic solutions.

In vitro study of nanoliposomes containing curcumin and doxycycline for enhanced antimicrobial photodynamic therapy against Aggregatibacter actinomycetemcomitans

The excessive inappropriate use of systemic antibiotics has contributed to the emergence of antibiotic-resistant pathogens, which pose a significant risk to the success of treatment. This study has approached this problem by developing doxycycline-loaded liposome doped with curcumin (NL-Cur^+Dox) for combination antibacterial therapy against Aggregatibacter actinomycetemcomitans. The characterization of formulation revealed encapsulation of both drugs in NL-Cur^+Dox with an average size of 239 nm and sustained release behavior. Transmission electron microscopy analysis confirmed the vesicular-shaped nanocarriers without any aggregation or crystallization. The cytotoxic and hemolytic activities of NL-Cur^+Dox were evaluated. The anti-biofilm and anti-metabolic effects of NL-Cur^+Dox -mediated antimicrobial photodynamic therapy (aPDT) were examined. The data indicated that NL-Cur^+Dox -mediated aPDT led to a significant reduction of biofilm (82.7%, p = 0.003) and metabolic activity (75%, p < 0.001) of A. actinomycetemcomitans compared to the control. NL-Cur^+Dox had no significant cytotoxicity to human gingival fibroblast cells under selected conditions (p = 0.074). In addition, the hemolytic activity of NL-Cur^+Dox were negligible (< 5%). These findings demonstrate the potential application of such potent formulations in reducing one of the main bacteria causing periodontitis where the NL-Cur^+Dox could be exploited to achieve an improved phototherapeutic efficiency.

Inhibition of biofilm formation and virulence factors of cariogenic oral pathogen Streptococcus mutans by natural flavonoid phloretin

Objectives

To evaluate the effect and mechanism of action of the flavonoid phloretin on the growth and sucrose-dependent biofilm formation of Streptococcus mutans.

Methods

Minimum inhibitory concentration, viability, and biofilm susceptibility assays were conducted to assess antimicrobial and antibiofilm effect of phloretin. Biofilm composition and structure were analysed with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Water-soluble (WSG) and water-insoluble glucan (WIG) were determined using anthrone method. Lactic acid measurements and acid tolerance assay were performed to assess acidogenicity and aciduricity. Reverse transcription quantitative PCR (RT-qPCR) was used to measure the expression of virulence genes essential for surface attachment, biofilm formation, and quorum sensing.

Results

Phloretin inhibited S. mutans growth and viability in a dose-dependent manner. Furthermore, it reduced gtfB and gtfC gene expression, correlating with the reduction of extracellular polysaccharides (EPS)/bacteria and WIG/WSG ratio. Inhibition of comED and luxS gene expression, involved in stress tolerance, was associated with compromised acidogenicity and aciduricity of S. mutans.

Conclusions

Phloretin exhibits antibacterial properties against S. mutans, modulates acid production and tolerance, and reduces biofilm formation.

Clinical significance

Phloretin is a promising natural compound with pronounced inhibitory effect on key virulence factors of the cariogenic pathogen, S. mutans.

Using Catechol and Zwitterion-Functionalized Copolymers to Prevent Dental Bacterial Adhesion

In this manuscript, we report the synthesis of zwitterionic copolymers and their ability to form antifouling coatings on porous hydroxyapatite as a mimic of dental coatings. Specifically, we systematically investigated how altering the composition of copolymers of catechol methacrylate (Cat-MA or 2) and methacryloyloxyethyl phosphorylcholine (2-MPC) with varying catechol-to-zwitterion ratios impacted their adhesive and antifouling properties, allowing for the rational design of functional coatings. Characterization by ellipsometry, contact angle goniometry, and X-ray photoelectron spectroscopy revealed the presence of hydrophilic copolymer coatings of ∼10 nm thickness. Notably, these copolymers adhered to hydroxyapatite and reduced the level of attachment of both Gram-negative Escherichia coli and Gram-positive Streptococcus oralis. Additionally, in vitro experiments that mimicked the complex mouth environment (i.e., swallowing and using mouthwash) were employed to evaluate S. oralis adhesion, finding that the copolymer coatings reduced the quantity of adhered bacteria. We suggest that these copolymers provide insights into the design of antifouling coatings that are appropriate for use in oral care.

pH-Responsive Biomaterials for the Treatment of Dental Caries-A Focussed and Critical Review

Dental caries is a common and costly multifactorial biofilm disease caused by cariogenic bacteria that ferment carbohydrates to lactic acid, demineralizing the inorganic component of teeth. Therefore, low pH (pH 4.5) is a characteristic signal of the localised carious environment, compared to a healthy oral pH range (6.8 to 7.4). The development of pH-responsive delivery systems that release antibacterial agents in response to low pH has gained attention as a targeted therapy for dental caries. Release is triggered by high levels of acidogenic species and their reduction may select for the establishment of health-associated biofilm communities. Moreover, drug efficacy can be amplified by the modification of the delivery system to target adhesion to the plaque biofilm to extend the retention time of antimicrobial agents in the oral cavity. In this review, recent developments of different pH-responsive nanocarriers and their biofilm targeting mechanisms are discussed. This review critically discusses the current state of the art and innovations in the development and use of smart delivery materials for dental caries treatment. The authors' views for the future of the field are also presented.

Effect of Charcoal, Probiotic, and Chlorhexidine Mouthwashes on Mechanical Properties and Surface Characterization of Ceramic-Coated Nickel-Titanium Orthodontic Arch Wires: A Comparative In-Vitro Study

AIM AND OBJECTIVES

To determine the impact on the mechanical properties and surface features of ceramic-coated nickel-titanium (CC-Ni-Ti) archwires when subjected to charcoal, probiotic, and chlorhexidine mouthwashes in in vitro conditions.

MATERIALS AND METHODS

Eighty samples of 25 mm were cut from the posterior end of preformed maxillary 0.016'' CC-Ni-Ti super elastic archwires (Koden Company, USA) and distributed into four equal groups. Each group of wires was immersed in artificial saliva (Wet Mouth Mouthwash, ICPA Health Products Ltd., India) (control), charcoal mouthwash (Hello activated charcoal extra freshening mouthwash, Hello Products LLC, USA), probiotic mouthwash (Perfora, Probiotic Rinse, India), and 0.2% chlorhexidine gluconate mouthwash (Sensorange, Orange Biotech, Pvt., Ltd., India) (experimental groups) for 90 min at 37 °C. All samples were taken out of their respective solutions and washed with distilled water prior to testing. A three-point bending test was performed on 15 samples from each group using a universal testing device. During the loading and unloading of the archwires, the yield strength (YS), flexural modulus of elasticity (E), and spring back ratio (YS/E) were calculated. The remaining five wires from each group were observed under the scanning electron microscope (SEM) for surface topography evaluation.

RESULTS

The mean differences of loading YS, E, and YS/E between chlorhexidine and charcoal are 302.91 MPa, 4.28 GPa, and 0.0004, whereas unloading values are 172.32 MPa, 4.16 GPa, and 0.0003, respectively, with a statistical significance of <0.001 in terms of YS and E. The mean differences of loading YS, E, and YS/E between charcoal and probiotic are 305.36 MPa, 4.54 GPa, and 0.0005, whereas unloading values are 173.77 MPa, 3.66 GPa, and 0.0003, respectively, with a statistical significance of <0.001 in terms of YS and E. The mean differences of loading YS, E, and YS/E between chlorhexidine and probiotic are 2.45 MPa, 0.26 GPa, and 0.00007, whereas unloading values are 1.44 MPa, 0.49 GPa, and 0.0000533, respectively, with no statistical significance of >0.001 in terms of YS, E, and YS/E. Surface topography alteration was clearly appreciated in the charcoal and probiotic mouthwash groups compared to charcoal mouthwash.

CONCLUSIONS

Loading and unloading of 0.016" ceramic-coated nickel-titanium archwires showed an increase in mechanical properties except for the spring back ratio on exposure to chlorhexidine, probiotic, and charcoal mouthwashes. Chlorhexidine and probiotic mouthwashes had a higher yield strength and flexural modulus of elasticity in comparison with charcoal mouthwash and artificial saliva on 0.016" ceramic-coated nickel-titanium archwires. More corrosive changes were seen on 0.016" ceramic-coated nickel-titanium archwires when immersed in chlorhexidine, followed by probiotic and charcoal mouthwashes.

Antimicrobial activity of Desplac® oral gel in the subgingival multispecies biofilm formation

Natural products are well-known due to their antimicrobial properties. This study aimed to evaluate the antimicrobial effect of Desplac® product (composed of Aloe Vera, Propolis Extract, Green Tea, Cranberry, and Calendula) on the subgingival biofilm. Two different protocols were used to treat the 33-species biofilms: (A) 2×/day (12/12  h) for 1  min with Desplac® or Noplak Toothpaste (Chlorhexidine + Cetylpyridinium Chloride) or Oral B ProGengiva (stannous Fluoride) or a placebo gel; (B) a 12-h use of the Desplac® product or 0.12% chlorhexidine gel or a placebo gel. After 7 days of biofilm formation, the metabolic activity (MA) and biofilm profile were determined by 2,3,5-triphenyltetrazolium chloride and Checker-board DNA-DNA hybridization, respectively. Statistical analysis used the Kruskal-Wallis test followed by Dunn's post-hoc. In protocol A, all treatments presented reduced MA compared to the placebo (p ≤ 0.05). The Desplac®-treated biofilm showed a similar microbial profile to other antimicrobials, although with higher bacterial total counts. In protocol B, MA of Desplac®-treated biofilms was lower than the placebo's MA but higher than chlorhexidine-treated biofilms (p ≤ 0.05). Pathogen levels in Desplac®-treated biofilms were lower than in placebo-treated biofilms and elevated compared to the chlorhexidine-treated biofilms (p ≤ 0.05). Desplac® inhibited the biofilm development and disrupted the mature subgingival biofilm, highlighting its effect on Tannerella forsythia counts.

Evaluation of Anti-plaque and Anti-gingivitis Efficacy of Two Commercially Available Herbal and Non-herbal Toothpastes

BACKGROUND

 Plaque-associated oral disease affects a considerable portion of the population and is considered one of the major causes of tooth loss. The presence of plaque may be the reason for dental caries, gingivitis, periodontal problems, and halitosis. Many mechanical aids are used to control plaque, including toothbrushes, dental floss, mouth rinses, and dentifrices, and the most effective method of controlling gingivitis is supragingival plaque control.

AIM AND OBJECTIVE

To evaluate and compare the anti-plaque and anti-gingivitis efficacy of commercially available herbal toothpaste (Meswak) and non-herbal toothpaste (Pepsodent).

MATERIALS AND METHOD

50 subjects aged between 10 and 15 years with a full complement of dentition were included in the study. The two toothpastes were provided to the subjects in plain white tubes by the investigator. Subjects were instructed to brush their teeth twice daily using the given toothpaste for 21 days. Plaque and gingival scores on days 0, 7, and 21 were recorded, and the data were subjected to statistical analysis.

RESULT

At the end of the 21-day study, there was a statistically significant difference between the groups for plaque and gingival scores.

CONCLUSION

The plaque and gingival scores were significantly reduced throughout the study in both groups. In comparison, the herbal dentifrices show more effectiveness in reducing plaque and gingival scores, but no statistically significant difference was seen between the two groups.

Preprocedural mouthwashes for infection control in dentistry-an update

OBJECTIVES

Aerosols and splatter are routinely generated in dental practice and can be contaminated by potentially harmful bacteria or viruses such as SARS-CoV-2. Therefore, preprocedural mouthwashes containing antiseptic agents have been proposed as a potential measure for infection control in dental practice. This review article aims to summarize the clinical (and, if insufficient, preclinical) evidence on preprocedural mouthwashes containing antiseptic agents and to draw conclusions for dental practitioners.

METHODS

Literature on preprocedural mouthwashes for reduction of bacterial or viral load in dental aerosols was searched and summarized.

RESULTS

Preprocedural mouthwashes, particularly those containing chlorhexidine digluconate (CHX), cetylpyridinium chloride (CPC), or essential oils (EO), can significantly reduce the bacterial load in dental aerosols. With respect to viruses such as HSV-1, there are too little clinical data to draw any clear recommendations. On the other hand, clinical data is consolidating that CPC-containing mouthwashes can temporarily reduce the intraoral viral load and infectivity in SARS-CoV-2 positive individuals. Nevertheless, potential risks and side effects due to regular antiseptic use such as ecological effects or adaptation of bacteria need to be considered.

CONCLUSIONS

The use of preprocedural mouthwashes containing antiseptics can be recommended according to currently available data, but further studies are needed, particularly on the effects on other viruses besides SARS-CoV-2. When selecting a specific antiseptic, the biggest data basis currently exists for CHX, CPC, EO, or combinations thereof.

CLINICAL RELEVANCE

Preprocedural mouthwashes containing antiseptics can serve as part of a bundle of measures for protection of dental personnel despite some remaining ambiguities and in view of potential risks and side effects.

The benefits of propolis in periodontal therapy. A scoping review of preclinical and clinical studies

ETHNOPHARMACOLOGICAL RELEVANCE

The treatment of periodontal disease (PD) is aimed at adequate control of bacterial plaque. In many patients mechanical methods are unable to eliminate this plaque leading to the need for adjuvant chemical products. Propolis is a natural product that has demonstrated therapeutic properties and has shown to be effective as an anti-inflammatory and antibacterial agent in dentistry.

AIM OF THE STUDY

Considering the beneficial effects of propolis on various oral conditions, this study aimed to review, update and summarize the available evidence on the benefits of propolis in in vitro studies, animal models, and human clinical trials on non-surgical periodontal therapy.

MATERIALS AND METHODS

An electronic search in three databases was performed up to December 2021. The search strategy included the terms "propolis" and "periodontal disease" to identify relevant studies on the potential advantages of propolis in periodontal therapy in in vitro studies, animal models, and human clinical trials.

RESULTS

The search yielded 538 results, discarding 459 studies that did not clearly meet the inclusion criteria. A total of 42 studies were included: 18 in vitro, one animal, and 23 randomized clinical trials. In vitro studies have demonstrated that propolis has antimicrobial activity against periodontal pathogens and clinical studies have reported its use as an adjunct to non-surgical periodontal therapy. The clinical effects of propolis have been reported in conjunction with prophylaxis, polishing, and scaling and root planing (SRP). It has shown to have anti-plaque activity and improve gingival health. Propolis was found to be more effective in improving clinical parameters than conventional treatment (SRP alone) and demonstrated similar efficacy in treating chronic periodontitis compared to positive controls. Only one study reported an allergic reaction.

CONCLUSION

The evidence available on the benefits of propolis in in vitro studies, animal models, and clinical trials suggests that propolis could be a promising adjunct to conventional therapy of gingivitis and periodontitis. However, further studies are needed to determine its superiority to other therapies in the treatment of PD.

The Antimicrobial Activity of Curcumin and Xanthohumol on Bacterial Biofilms Developed over Dental Implant Surfaces

In search for natural products with antimicrobial properties for use in the prevention and treatment of peri-implantitis, the purpose of this investigation was to evaluate the antimicrobial activity of curcumin and xanthohumol, using an in vitro multi-species dynamic biofilm model including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of curcumin (5 mM) and xanthohumol (100 μM) extracts, and the respective controls, were evaluated with 72-h biofilms formed over dental implants by their submersion for 60 seconds. The evaluation was assessed by quantitative polymerase chain reaction (qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). For the data analysis, comparisons were tested applying ANOVA tests with post-hoc Bonferroni corrections to evaluate the antimicrobial activity of both extracts. With qPCR, statistically significant reductions in bacterial counts were observed for curcumin and xanthohumol, when compared to the negative control. The results with CLSM and SEM were consistent with those reported with qPCR. It was concluded that both curcumin and xanthohumol have demonstrated antimicrobial activity against the six bacterial species included in the dynamic in vitro biofilm model used.

Daily use of chlorine dioxide effectively treats halitosis: A meta-analysis of randomised controlled trials

OBJECTIVES

We aimed to conduct a systematic review on published data in order to investigate the efficacy of mouthwash products containing chlorine dioxide in halitosis.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

Our search was conducted on 14th October 2021. We searched the following electronic databases: MEDLINE, Embase, Scopus, Web of Science, and CENTRAL. We analysed data on adults with halitosis, included only randomised controlled trials and excluded in vitro and animal studies. The interventional groups used chlorine dioxide, and the comparator groups used a placebo or other mouthwash. Our primary outcomes were changes in organoleptic test scores (OLS) and Volatile Sulfur Compound (VSC) levels from baseline to the last available follow-up.

RESULTS

We found 325 articles in databases. After the selection process, ten articles were eligible for qualitative synthesis, and 7 RCTs with 234 patients were involved in the meta-analysis. Our findings showed a significant improvement in the parameters of the chlorine dioxide group compared to the placebo group in OLS one-day data (mean difference (MD): -0.82; 95% confidence intervals (95% CIs): [-1.04 --0.6]; heterogeneity: I2 = 0%, p = 0.67); and one-week OLS data (MD: -0.24; 95% CIs: [-0.41 --0.07]; I2 = 0%, p = 0.52); and also changes in H2S one-day data (standardised mean difference (SMD): -1.81; 95% CIs: [-2.52 --1.10]); I2 = 73.4%, p = 0.02).

CONCLUSION

Our data indicate that chlorine dioxide mouthwash may be a good supportive therapy in oral halitosis without known side effects.

Clinical efficacy of photodynamic therapy on halitosis: a systematic review and meta-analysis

Halitosis is a widespread health problem with complex factors, and therapeutic effects sometimes are unsatisfactory. Plenty of clinical trials have tried to prove the effectiveness of photodynamic therapy (PDT), but the results are indeterminate. This study aimed to evaluate the clinical efficacy of PDT on halitosis. We searched PubMed, Cochrane Library, Embase, Web of Science, and Scopus from inception to August 10, 2022, and only studies about the PDT on halitosis were included. The criteria for meta-analysis comprised randomized controlled trials (RCTs) comparing the treatment of PDT with tongue scraper (TS) immediately after the halitosis therapy and during a 7-, 14-, 30-, and 90-day follow-up. Eight eligible studies involving 345 patients were included in this study. It was shown that PDT (MD =  - 34.49, 95% CI [- 66.34, - 2.64], P = 0.03) or PDT + TS (MD =  - 67.72, 95% CI [- 101.17, - 34.28], P < 0.001) had better efficacy than TS on the H2S concentration reduction immediately after the halitosis therapy. No significant differences were observed in reducing the H2S among TS, PDT alone, and PDT + TS at the follow-up. Besides, no difference between PDT and TS was found in the reduction of CH3SCH3 and CH3SH. Based on the current evidence, PDT and PDT + TS demonstrate efficacy in the treatment of halitosis in the short term, and PDT was shown to be a beneficial and promising therapeutic method.

3D Porous Collagen Matrices-A Reservoir for In Vitro Simultaneous Release of Tannic Acid and Chlorhexidine

The treatment of wounds occurring accidentally or as a result of chronic diseases most frequently requires the use of appropriate dressings, mainly to ensure tissue regeneration/healing, at the same time as treating or preventing potential bacterial infections or superinfections. Collagen type I-based scaffolds in tandem with adequate antimicrobials can successfully fulfill these requirements. In this work, starting from the corresponding hydrogels, we prepared a series of freeze-dried atelocollagen type I-based matrices loaded with tannic acid (TA) and chlorhexidine digluconate (CHDG) as active agents with a broad spectrum of antimicrobial activity and also as crosslinkers for the collagen network. The primary aim of this study was to design an original and reliable algorithm to in vitro monitor and kinetically analyze the simultaneous release of TA and CHDG from the porous matrices into an aqueous solution of phosphate-buffered saline (PBS, pH 7.4, 37 °C) containing micellar carriers of a cationic surfactant (hexadecyltrimethylammonium bromide, HTAB) as a release environment that roughly mimics human extracellular fluids in living tissues. Around this central idea, a comprehensive investigation of the lyophilized matrices (morpho-structural characterization through FT-IR spectroscopy, scanning electron microscopy, swelling behavior, resistance against the collagenolytic action of collagenase type I) was carried out. The kinetic treatment of the release data displayed a preponderance of non-Fickian-Case II diffusion behavior, which led to a general anomalous transport mechanism for both TA and CHDG, irrespective of their concentrations. This is equivalent to saying that the release regime is not governed only by the gradient concentration of the releasing components inside and outside the matrix (like in ideal Fickian diffusion), but also, to a large extent, by the relaxation phenomena of the collagen network (determined, in turn, by its crosslinking degree induced by TA and CHDG) and the dynamic capacity of the HTAB micelles to solubilize the two antimicrobials. By controlling the degree of physical crosslinking of collagen with a proper content of TA and CHDG loaded in the matrix, a tunable, sustainable release profile can be obtained.

Overview on Adjunct Ingredients Used in Hydroxyapatite-Based Oral Care Products

Hydroxyapatite, Ca₅(PO₄)₃(OH), is a biomimetic active ingredient, which is used in commercial oral care products such as toothpastes and mouthwashes worldwide. Clinical studies (in vivo) as well as in situ and in vitro studies have shown the preventive effects of hydroxyapatite in various field of oral care. In some products, hydroxyapatite is combined with other active ingredients, to achieve an additional antibacterial effect or to promote gum health. This review analyzes the efficacy of six selected natural and nature-inspired ingredients that are commonly used together with hydroxyapatite. These additional actives are either antibacterial (lactoferrin, xylitol, and zinc) or promote gum health (allantoin, bisabolol, and hyaluronic acid). A systematic literature search was performed, and all studies found on each ingredient were analyzed. In summary, all analyzed ingredients mentioned in this review are well described in scientific studies on their beneficial effect for oral health and can be used to expand the preventive effect of hydroxyapatite in oral care products.

The efficacy of mouthwashes in reducing SARS-CoV-2 viral loads in human saliva: A systematic review

This systematic review aimed to evaluate existing randomized controlled trials (RCT) and cohort studies on the efficacy of mouthwashes in reducing SARS-CoV-2 viral loads in human saliva. Searches with pertinent search terms were conducted in PubMed, MEDLINE, Scopus, and Web of Science databases for relevant records published up to Oct 15, 2022. Google Scholar and ProQuest were searched for grey literature. Manual searches were conducted as well for any pertinent articles. The protocol was prospectively registered at PROSPERO (CRD42022324894). Eligible studies were critically appraised for risk of bias and quality of evidence to assess the efficacy of mouthwash in reducing the SARS-CoV-2 viral load in human saliva. Eleven studies were included. The effect on viral load using various types of mouthwash was observed, including chlorhexidine (CHX), povidone-iodine (PI), cetylpyridinium chloride (CPC), hydrogen peroxide (HP), ß-cyclodextrin-citrox mouthwash (CDCM), and Hypochlorous acid (HCIO). Eight articles discussed CHX use. Five were found to be significant and three did not show any significant decrease in viral loads. Eight studies reviewed the use of PI, with five articles identifying a significant decrease in viral load, and three not showing a significant decrease in viral load. HP was reviewed in four studies, two studies identified significant viral load reductions, and two did not. CPC was reviewed in four studies, two of which identified significant viral load reductions, and two did not. CDCM was reviewed in one article which found a significant decrease in viral load reduction. Also, HCIO which was evaluated in one study indicated no significant difference in CT value. The current systematic review indicates that based on these eleven studies, mouthwashes are effective at reducing the SARS-CoV-2 viral load in human saliva. However, further studies should be performed on larger populations with different mouthwashes. The overall quality of evidence was high.

Antibiotic Resistance of Selected Bacteria after Treatment of the Supragingival Biofilm with Subinhibitory Chlorhexidine Concentrations

Due to increasing rates of antibiotic resistance and very few novel developments of antibiotics, it is crucial to understand the mechanisms of resistance development. The aim of the present study was to investigate the adaptation of oral bacteria to the frequently used oral antiseptic chlorhexidine digluconate (CHX) and potential cross-adaptation to antibiotics after repeated exposure of supragingival plaque samples to subinhibitory concentrations of CHX. Plaque samples from six healthy donors were passaged for 10 days in subinhibitory concentrations of CHX, while passaging of plaque samples without CHX served as control. The surviving bacteria were cultured on agar plates and identified with Matrix-assisted Laser Desorption/Ionization-Time of Flight-Mass spectrometry (MALDI-TOF). Subsequently, the minimum inhibitory concentrations (MIC) of these isolates toward CHX were determined using a broth-microdilution method, and phenotypic antibiotic resistance was evaluated using the epsilometertest. Furthermore, biofilm-forming capacities were determined. Repeated exposure of supragingival plaque samples to subinhibitory concentrations of CHX led to the selection of oral bacteria with 2-fold up to 4-fold increased MICs toward CHX. Furthermore, these isolates showed up to 12-fold increased MICs towards some antibiotics such as erythromycin and clindamycin. Conversely, biofilm-forming capacity was decreased. In summary, this study shows that oral bacteria are able to adapt to CHX, while also decreasing their susceptibility to antibiotics.

Effects of Photodynamic Therapy on Streptococcus mutans and Enamel Remineralization of Multifunctional TiO2-HAP Composite Nanomaterials

BACKGROUND

As photosensitizer and photocatalyst, titanium dioxide (TiO₂) can produce a photodynamic reaction for antibacterial treatment. This study aims to explore a Titanium dioxide/nano-hydroxyapatite (TiO₂-HAP) composite combined with the dental curing lamp (385-515 nm) in clinical which could inhibit the dental plaque biofilm formed by Streptococcus mutans (S. mutans) and promote the enamel surface remineralization simultaneously.

METHODS

X-ray Diffraction (XRD) and high resolution transmission electron microscope (HRTEM) were used to detect the characterization of TiO₂-HAP composite nanomaterials. Photodynamic properties of TiO₂-HAP were detected by Diffuse reflectance spectrum (DRS) and fluorescence spectroscopy. Bacterial growth was measured by reading the absorbance of bacterial cultures and confocal microscope was used to observe the biofilm removal ability of nanomaterials. The ability of TiO₂-HAP to promote enamel remineralization was measured by Scanning electron microscope (SEM).

RESULTS

The OD 600 of S. mutans was 0.76 in the control group and 0.13 in group of TiO₂-HAP with exposure to light-emitting diode (LED) (150 mW/cm²) for 5 min, suggesting its sustained antibacterial potency and inhibition of the metabolic activity of dental plaque microcosm biofilm. Also, the release of calcium and phosphorus ions in TiO₂-HAP can promote enamel mineralization simultaneously. After 15 days of remineralization, the Ca/P ratio of demineralized enamel surface increased from 1.28 to 1.67, which was similar to that of normal enamel.

CONCLUSIONS

The TiO₂-HAP exhibit a promising anti-bacterial activity and remineralization capacity which can prevent the occurrence of caries to the greatest extent and promote the biomimetic mineralization of dental tissues.