Effect of mouth cleaning with hinokitiol-containing gel on oral malodor: a randomized, open-label pilot study

Current and Potential Applications of Monoterpenes and Their Derivatives in Oral Health Care

Plant products have been employed in medicine for centuries. As the world becomes more health-conscious, there is a growing interest in natural and minimally processed products for oral health care. This has led to an increase in research into the bioactive compounds found in plant products, particularly monoterpenes. Monoterpenes are known to have beneficial biological properties, but the specific mechanisms by which they exert their effects are not yet fully understood. Despite this, some monoterpenes are already being used in oral health care. For example, thymol, which has antibacterial properties, is an ingredient in varnish used for caries prevention. In addition to this, monoterpenes have also demonstrated antifungal, antiviral, and anti-inflammatory properties, making them versatile for various applications. As research continues, there is potential for even more discoveries regarding the benefits of monoterpenes in oral health care. This narrative literature review gives an overview of the biological properties and current and potential applications of selected monoterpenes and their derivatives in oral health care. These compounds demonstrate promising potential for future medical development, and their applications in future research are expected to expand.

ORGANOLEPTIC AND HALITOMETRIC ASSESSMENTS DO NOT CORRELATE WELL IN INTRA-ORAL HALITOSIS: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

The gold standard method for diagnosing oral halitosis is the subjective organoleptic measurement. Device-supported methods are also widespread worldwide. The challenges and safety concerns around performing organoleptic measurements during pandemics and the diversity of measuring device alternatives raised our clinical question: which halitometer is the most suitable for diagnosing halitosis?

METHODS

This systematic review was registered in PROSPERO (ID CRD42022320024). The search was performed on March 23, 2022 in the following electronic databases: MEDLINE, Embase, Scopus, Web of Science, and CENTRAL. Adult populations with or without halitosis were included, and patients with systemic diseases were excluded. Organoleptic (subjective) measurement and the device-supported (objective) methods were compared; the primary outcome was the correlation coefficient, and the secondary was the specificity and sensitivity of the devices. QUADAS-2 and QUADAS-C were used to evaluate the risk of bias in the studies. Random-effects meta analyses were performed on the outcomes, and the secondary outcomes were plotted on a common ROC plot.

RESULTS

A total of 1231 records were found in the 5 databases. After the selection process, 76 articles were eligible for the systematic review, and 14,635 patients were involved in the qualitative analysis. The pooled Spearman's correlation coefficient (c.c.) for sulfide monitors was 0.65; 95% CIs: [0.53-0.74]; I2 = 95%, P < .01. The pooled Spearman's c.c. for portable gas chromatographs was 0.69; 95% CIs: [0.63-0.74]; I2 = 12%, P < .01. The pooled Spearman's c.c. for gas chromatographs was 0.76; 95% CIs: [0.67-0.83]; I2 = 0%, P < .01.

DISCUSSION

None of the most commonly used halitometers proved to be significantly superior to the others. Halimeter and OralChroma measurements did not correlate well with the organoleptic level of oral halitosis in adults. Therefore, better halitometers need to be developed as an alternative to organoleptic measurements.

Hinokitiol Dysregulates Metabolism of Carcinoma Cell Lines and Induces Downregulation of HPV16E6 and E7 Oncogenes and p21 Upregulation in HPV Positive Cell Lines

Background: Hinokitiol (β-thujaplicin), isolated from the wood of Chamaecyparis taiwanensis, has a wide variety of biological properties including anti-inflammatory, anti-microbial, and anti-tumor effects. Therefore, hinokitiol has become a frequent additive in oral and other healthcare products. Objectives: Our goal was to determine the anti-tumor activity of hinokitiol on human papillomavirus (HPV) positive (n = 3) and negative (n = 2) cell lines derived from cervical or head and neck squamous cell carcinoma (HNSCC) and keratinocyte cell lines (n = 3) transformed spontaneously or with HPV16E6 and E7 oncogenes. Methods: The cell-lines were exposed to hinokitiol at different concentrations (0–200 µM) for 24 h. Cell metabolism, proliferation, and the cell cycle distribution were assessed by MTT- and 3H-thymidine incorporation and flow cytometry. Expressions of p21 and on HPV16E6 and E7 oncogenes were assessed by qPCR. Results: In all carcinoma cell lines, hinokitiol treatment declined the metabolic activity irrespective of the HPV status. This decline was statistically significant, however, only in HPV-positive cell lines CaSki and UD-SCC-2 when exposed to hinokitiol concentrations at 100 and 200 µM, respectively (p < 0.05). Immortalized cell lines, HMK and HPV-positive IHGK, were more sensitive as a similar metabolic effect was achieved at lower hinokitiol concentrations of 3.1, 6.25, and 50 µM, respectively. Hinokitiol blocked DNA synthesis of all carcinoma cell lines without evident association with HPV status. G1 cell cycle arrest and p21 upregulation was found in all cell lines after hinokitiol treatment at higher concentration. However, when the p21 results of all HPV-positive cells were pooled together, the increase in p21 expression was statistically significantly higher in HPV-positive than in HPV-negative cell lines (p = 0.03), but only at the highest hinokitiol concentration (200 µM). In HPV-positive cell lines hinokitiol declined the expression of HPV16E7 and E6 along the increase of p21 expression. The dose-dependent inverse correlation between p21 and E7 was statistically significant in SiHa cells (r = −0.975, p-value = 0.03) and borderline in UD-SCC-2 cells (r = −0.944, p-value = 0.06), in which p21 and E6 were also inversely correlated (r = −0.989). Conclusions: Our results indicate that hinokitiol might have potential in preventing the progress of immortalized cells toward malignancy and the growth of malignant lesions. Hinokitiol can also influence on the progression of HPV-associated lesions by downregulating the E6 and E7 expression.

A Potential “Vitaminic Strategy” against Caries and Halitosis

Streptococcus mutans and Fusobacterium nucleatum are two key bacteria of the oral microbiota. Due to their ability to form biofilms on oral tissues, they are both involved in the onset of the most common oral diseases. F. nucleatum is also the principal producer of hydrogen sulfide (H2S), causative of the awkward bad breath of halitosis. In this study, the oral product Vea® Oris, made by vitamin E and capric/caprylic acid only, was evaluated as a potential treatment for the most common oral diseases. Different concentrations of the product were tested against both S. mutans and F. nucleatum. The effect on planktonic and biofilm growth was investigated for both strains, and for F. nucleatum, the influence on H2S production was evaluated. From our data, the product did not relevantly reduce the planktonic growth of both strains, whereas it validly counteracted biofilm assemblage. Moreover, an interesting trend of H2S reduction was highlighted. Overall, these results suggested, on the one hand, a synergistic antimicrobial–antibiofilm action of two Vea® Oris components and, together, potential modulation activity on H2S production. However, the study should be implemented to confirm these only preliminary findings, certainly extending the panel of tested bacteria and using alternative methods of detection.

Role of Hydrogen Sulfide in Oral Disease

Oral diseases are among the most common human diseases yet less studied. These diseases affect both the physical, mental, and social health of the patients resulting in poor quality of life. They affect all ages, although severe stages are mostly observed in older individuals. Poor oral hygiene, genetics, and environmental factors contribute enormously to the development and progression of these diseases. Although there are available treatment options for these diseases, the recurrence of the diseases hinders their efficiency. Oral volatile sulfur compounds (VSCs) are highly produced in oral cavity as a result of bacteria activities. Together with bacteria components such as lipopolysaccharides, VSCs participate in the progression of oral diseases by regulating cellular activities and interfering with the immune response. Hydrogen sulfide (H2S) is a gaseous neurotransmitter primarily produced endogenously and is involved in the regulation of cellular activities. The gas is also among the VSCs produced by oral bacteria. In numerous diseases, H2S have been reported to have dual effects depending on the cell, concentration, and donor used. In oral diseases, high production and subsequent utilization of this gas have been reported. Also, this high production is associated with the progression of oral diseases. In this review, we will discuss the production of H2S in oral cavity, its interaction with cellular activities, and most importantly its role in oral diseases.

Effects of Hinokitiol and Dicalcium Phosphate on the Osteoconduction and Antibacterial Activity of Gelatin-Hyaluronic Acid Crosslinked Hydrogel Membrane In Vitro

Many hydrogel-based crosslinking membranes have been designed and tailored to meet the needs of different applications. The aim of this research is to design a bifunctional hydrogel membrane with antibacterial and osteoconducting properties to guide different tissues. The membrane uses gelatin and hyaluronic acid as the main structure, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride as the crosslinker, hinokitiol as the antibacterial agent, and dicalcium phosphate anhydrous (DCPA) micron particles for osteoconduction. Results show that the hydrogel membrane with added DCPA and impregnated hinokitiol has a fixation index higher than 88%. When only a small amount of DCPA is added, the tensile strength does not decrease significantly. The tensile strength decreases considerably when a large amount of modified DCPA is added. The stress–strain curve shows that the presence of a large amount of hinokitiol in hydrogel membranes results in considerably improved deformation and toughness properties. Each group impregnated with hinokitiol exhibits obvious antibacterial capabilities. Furthermore, the addition of DCPA and impregnation with hinokitiol does not exert cytotoxicity on cells in vitro, indicating that the designed amount of DCPA and hinokitiol in this study is appropriate. After a 14-day cell culture, the hydrogel membrane still maintains a good shape because the cells adhere and proliferate well, thus delaying degradation. In addition, the hydrogel containing a small amount of DCPA has the best cell mineralization effect. The developed hydrogel has a certain degree of flexibility, degradability, and bifunctionality and is superficial. It can be used in guided tissue regeneration in clinical surgery.

Alternative therapies in controlling oral malodour: a systematic review

Is there a role for alternative therapies in controlling intra-oral halitosis? Treatments other than tongue cleaning and anti-halitosis products containing zinc, chlorhexidine and cetylpyridinium chloride were considered as alternative therapies. Four databases were searched (PubMed, EMBASE, Web of Science and The Cochrane Library). Inclusion criteria were: examination of alternative halitosis therapies, study population with oral malodour, a (negative or positive) control group and evaluation of breath odour via organoleptic and/or instrumental assessment. Data were extracted for descriptive analysis. The screening of 7656 titles led to the inclusion of 26 articles. Analysis showed heterogeneity concerning the population of interest (from cysteine-induced to genuine halitosis), the examined treatment and the reported outcomes. This made a meta-analysis impossible. Essential oils, fluoride-containing products and herbal substances were the most studied. Results varied enormously and none of the active ingredients had an unambiguously positive effect on the malodour. The risk of bias was assessed as high in all articles. Given the fact that little evidence was found for each of the investigated treatments, it could be concluded that there is currently insufficient evidence that alternative therapies are of added value in the treatment of halitosis.Clinical relevanceScientific rationale:Halitosis is a common problem causing social isolation. Out of embarrassment, patients search the internet, leading to many questions about alternative solutions (e.g. oil pulling, herbs). This is the first systematic review on these alternative therapies.Principal findings: Results varied among studies. Some promising results were found for fluoride-containing toothpastes and probiotics. For other products (such as herbal and antibacterial products and essential oils) results were inconsistent. Long-term follow-up studies on these products are scarce. Moreover, the quality of the studies was poor.Practical implications:No clear evidence was found to support a certain alternative anti-halitosis therapy.

Interventions for managing halitosis

BACKGROUND

Halitosis or bad breath is a symptom in which a noticeably unpleasant breath odour is present due to an underlying oral or systemic disease. 50% to 60% of the world population has experienced this problem which can lead to social stigma and loss of self-confidence. Multiple interventions have been tried to control halitosis ranging from mouthwashes and toothpastes to lasers. This new Cochrane Review incorporates Cochrane Reviews previously published on tongue scraping and mouthrinses for halitosis.

OBJECTIVES

The objectives of this review were to assess the effects of various interventions used to control halitosis due to oral diseases only. We excluded studies including patients with halitosis secondary to systemic disease and halitosis-masking interventions.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 8 April 2019), the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 3) in the Cochrane Library (searched 8 April 2019), MEDLINE Ovid (1946 to 8 April 2019), and Embase Ovid (1980 to 8 April 2019). We also searched LILACS BIREME (1982 to 19 April 2019), the National Database of Indian Medical Journals (1985 to 19 April 2019), OpenGrey (1992 to 19 April 2019), and CINAHL EBSCO (1937 to 19 April 2019). The US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov (8 April 2019), the World Health Organization International Clinical Trials Registry Platform (8 April 2019), the ISRCTN Registry (19 April 2019), the Clinical Trials Registry - India (19 April 2019), were searched for ongoing trials. We also searched the cross-references of included studies and systematic reviews published on the topic. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) which involved adults over the age of 16, and any intervention for managing halitosis compared to another or placebo, or no intervention. The active interventions or controls were administered over a minimum of one week and with no upper time limit. We excluded quasi-randomised trials, trials comparing the results for less than one week follow-up, and studies including advanced periodontitis.

DATA COLLECTION AND ANALYSIS

Two pairs of review authors independently selected trials, extracted data, and assessed risk of bias. We estimated mean differences (MDs) for continuous data, with 95% confidence intervals (CIs). We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 44 trials in the review with 1809 participants comparing an intervention with a placebo or a control. The age of participants ranged from 17 to 77 years. Most of the trials reported on short-term follow-up (ranging from one week to four weeks). Only one trial reported long-term follow-up (three months). Three studies were at low overall risk of bias, 16 at high overall risk of bias, and the remaining 25 at unclear overall risk of bias. We compared different types of interventions which were categorised as mechanical debridement, chewing gums, systemic deodorising agents, topical agents, toothpastes, mouthrinse/mouthwash, tablets, and combination methods. Mechanical debridement: for mechanical tongue cleaning versus no tongue cleaning, the evidence was very uncertain for the outcome dentist-reported organoleptic test (OLT) scores (MD -0.20, 95% CI -0.34 to -0.07; 2 trials, 46 participants; very low-certainty evidence). No data were reported for patient-reported OLT score or adverse events. Chewing gums: for 0.6% eucalyptus chewing gum versus placebo chewing gum, the evidence was very uncertain for the outcome dentist-reported OLT scores (MD -0.10, 95% CI -0.31 to 0.11; 1 trial, 65 participants; very low-certainty evidence). No data were reported for patient-reported OLT score or adverse events. Systemic deodorising agents: for 1000 mg champignon versus placebo, the evidence was very uncertain for the outcome patient-reported visual analogue scale (VAS) scores (MD -1.07, 95% CI -14.51 to 12.37; 1 trial, 40 participants; very low-certainty evidence). No data were reported for dentist-reported OLT score or adverse events. Topical agents: for hinokitiol gel versus placebo gel, the evidence was very uncertain for the outcome dentist-reported OLT scores (MD -0.27, 95% CI -1.26 to 0.72; 1 trial, 18 participants; very low-certainty evidence). No data were reported for patient-reported OLT score or adverse events. Toothpastes: for 0.3% triclosan toothpaste versus control toothpaste, the evidence was very uncertain for the outcome dentist-reported OLT scores (MD -3.48, 95% CI -3.77 to -3.19; 1 trial, 81 participants; very low-certainty evidence). No data were reported for patient-reported OLT score or adverse events. Mouthrinse/mouthwash: for mouthwash containing chlorhexidine and zinc acetate versus placebo mouthwash, the evidence was very uncertain for the outcome dentist-reported OLT scores (MD -0.20, 95% CI -0.58 to 0.18; 1 trial, 44 participants; very low-certainty evidence). No data were reported for patient-reported OLT score or adverse events. Tablets: no data were reported on key outcomes for this comparison. Combination methods: for brushing plus cetylpyridium mouthwash versus brushing, the evidence was uncertain for the outcome dentist-reported OLT scores (MD -0.48, 95% CI -0.72 to -0.24; 1 trial, 70 participants; low-certainty evidence). No data were reported for patient-reported OLT score or adverse events.

AUTHORS' CONCLUSIONS

We found low- to very low-certainty evidence to support the effectiveness of interventions for managing halitosis compared to placebo or control for the OLT and patient-reported outcomes tested. We were unable to draw any conclusions regarding the superiority of any intervention or concentration. Well-planned RCTs need to be conducted by standardising the interventions and concentrations.

Antibacterial activity of hinokitiol against both antibiotic-resistant and -susceptible pathogenic bacteria that predominate in the oral cavity and upper airways

Hinokitiol, a component of the essential oil isolated from Cupressaceae, possesses antibacterial and antifungal activities and has been used in oral care products. In this study, the antibacterial activities of hinokitiol toward various oral, nasal and nasopharyngeal pathogenic bacteria, including Streptococcus mutans, Streptococcus sobrinus, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Fusobacterium nucleatum, methicillin-resistant and -susceptible Staphylococcus aureus, antibiotic-resistant and -susceptible Streptococcus pneumoniae, and Streptococcus pyogenes were examined. Growth of all these bacterial strains was significantly inhibited by hinokitiol, minimal inhibitory concentrations of hinokitiol against S. mutans, S. sobrinus, P. gingivalis, P. intermedia, A. actinomycetemcomitans, F. nucleatum, methicillin-resistant S. aureus, methicillin-susceptible S. aureus, antibiotic-resistant S. pneumoniae isolates, antibiotic-susceptible S. pneumoniae, and S. pyogenes being 0.3, 1.0, 1.0, 30, 0.5, 50, 50, 30, 0.3-1.0, 0.5, and 0.3 μg/mL, respectively. Additionally, with the exception of P. gingivalis, hinokitiol exerted bactericidal effects against all bacterial strains 1 hr after exposure. Hinokitiol did not display any significant cytotoxicity toward the human gingival epithelial cell line Ca9-22, pharyngeal epithelial cell line Detroit 562, human umbilical vein endothelial cells, or human gingival fibroblasts, with the exception of treatment with 500 μg/mL hinokitiol, which decreased numbers of viable Ca9-22 cells and gingival fibroblasts by 13% and 12%, respectively. These results suggest that hinokitiol exhibits antibacterial activity against a broad spectrum of pathogenic bacteria and has low cytotoxicity towards human epithelial cells.

Induction and inhibition of oral malodor

Volatile sulfur compounds (VSCs) such as hydrogen sulfide (H₂ S) and methyl mercaptan (CH₃ SH) are the main components of oral malodor, and are produced as the end products of the proteolytic processes of oral microorganisms. The main pathway of proteolysis is the metabolism of sulfur-containing amino acids by gram-negative anaerobic bacteria. Gram-positive bacteria may promote VSC production by gram-negative anaerobes by cleaving sugar chains from glycoproteins and thus providing proteins. A large variety of bacteria within the oral microbiota are thought to be involved in the complex phenomenon of halitosis. Oral microbiota associated with a lack of oral malodor, oral microbiota associated with severe and H₂ S-dominant oral malodor, and oral microbiota associated with severe and CH₃ SH-dominant oral malodor have been distinguished through molecular approaches using the 16S rRNA gene. Pathological halitosis may primarily be addressed through treatment of causative diseases. In all cases, plaque control is the basis of oral malodor control, and dentifrices, mouthwashes, and functional foods play a supplementary role in addition to brushing. Recently, the use of natural ingredients in products tends to be favored due to the increase in antibiotic-resistant strains and the side effects of some chemical ingredients. In addition, probiotics and vaccines are expected to offer new strategies for improving the oral conditions through mechanisms other than antibacterial agents.

β-Thujaplicin induces autophagic cell death, apoptosis, and cell cycle arrest through ROS-mediated Akt and p38/ERK MAPK signaling in human hepatocellular carcinoma

Hepatocellular carcinoma (HCC), a common liver malignancy worldwide, has high morbidity and mortality. β-Thujaplicin, a tropolone derivative, has been used in some health-care products and clinical adjuvant drugs, but its use for HCC is unknown. In this study, we found that β-Thujaplicin inhibits the growth of HCC cells, but not normal liver cells, with nanomolar potency. Mechanistically, we found that β-Thujaplicin could induce autophagy, as judged by western blot, confocal microscopy, and transmission electron microscopy. Further using β-Thujaplicin combined with an autophagy blocker or agonist treatment HepG2 cells, we found that β-Thujaplicin induced autophagic cell death (ACD) mediated by ROS caused inhibition of the Akt-mTOR signaling pathway. Moreover, β-Thujaplicin triggered HepG2 apoptosis and increased cleaved PARP1, cleaved caspase-3, and Bax/Bcl-2 ratio, which indicated that β-Thujaplicin induced apoptosis mediated by the mitochondrial-dependent pathway. We also found that increased expression of p21 and decreased expression of CDK7, Cyclin D1, and Cyclin A2 participating in β-Thujaplicin caused the S-phase arrest. It seems that β-Thujaplicin exerts these functions by ROS-mediated p38/ERK MAPK but not by JNK signaling pathway activation. Consistent with in vitro findings, our in vivo study verified that β-Thujaplicin treatment significantly reduced HepG2 tumor xenograft growth. Taken together these findings suggest that β-Thujaplicin have an ability of anti-HCC cells and may conducively promote the development of novel anti-cancer agents.

Two mechanisms of oral malodor inhibition by zinc ions

The aim of this study was to reveal the mechanisms by which zinc ions inhibit oral malodor. The direct binding of zinc ions to gaseous hydrogen sulfide (H2S) was assessed in comparison with other metal ions. Nine metal chlorides and six metal acetates were examined. To understand the strength of H2S volatilization inhibition, the minimum concentration needed to inhibit H2S volatilization was determined using serial dilution methods. Subsequently, the inhibitory activities of zinc ions on the growth of six oral bacterial strains related to volatile sulfur compound (VSC) production and three strains not related to VSC production were evaluated. Aqueous solutions of ZnCl2, CdCl2, CuCl2, (CH3COO)2Zn, (CH3COO)2Cd, (CH3COO)2Cu, and CH3COOAg inhibited H2S volatilization almost entirely. The strengths of H2S volatilization inhibition were in the order Ag+ > Cd2+ > Cu2+ > Zn2+. The effect of zinc ions on the growth of oral bacteria was strain-dependent. Fusobacterium nucleatum ATCC 25586 was the most sensitive, as it was suppressed by medium containing 0.001% zinc ions. Zinc ions have an inhibitory effect on oral malodor involving the two mechanisms of direct binding with gaseous H2S and suppressing the growth of VSC-producing oral bacteria.

Natural product β-thujaplicin inhibits homologous recombination repair and sensitizes cancer cells to radiation therapy

Investigation of natural products is an attractive strategy to identify novel compounds for cancer prevention and treatment. Numerous studies have shown the efficacy and safety of natural products, and they have been widely used as alternative treatments for a wide range of illnesses, including cancers. However, it remains unknown whether natural products affect homologous recombination (HR)-mediated DNA repair and whether these compounds can be used as sensitizers with minimal toxicity to improve patients' responses to radiation therapy, a mainstay of treatment for many human cancers. In this study, in order to systematically identify natural products with an inhibitory effect on HR repair, we developed a high-throughput image-based HR repair screening assay and screened a chemical library containing natural products. Among the most interesting of the candidate compounds identified from the screen was β-thujaplicin, a bioactive compound isolated from the heart wood of plants in the Cupressaceae family, can significantly inhibit HR repair. We further demonstrated that β-thujaplicin inhibits HR repair by reducing the recruitment of a key HR repair protein, Rad51, to DNA double-strand breaks. More importantly, our results showed that β-thujaplicin can radiosensitize cancer cells. Additionally, β-thujaplicin sensitizes cancer cells to PARP inhibitor in different cancer cell lines. Collectively, our findings for the first time identify natural compound β-thujaplicin, which has a good biosafety profile, as a novel HR repair inhibitor with great potential to be translated into clinical applications as a sensitizer to DNA-damage-inducing treatment such as radiation and PARP inhibitor. In addition, our study provides proof of the principle that our robust high-throughput functional HR repair assay can be used for a large-scale screening system to identify novel natural products that regulate DNA repair and cellular responses to DNA damage-inducing treatments such as radiation therapy.

Dental materials and their performance for the management of screw access channels in implant-supported restorations

Unsuccessfully sealed screw access channels of prosthetic implant abutments may lead to malodor or peri-implant diseases in gingival tissues adjacent to implant-supported restorations. Therefore, 72 sets of screw channel analogs with six different materials incorporated (Polytetrafluoroethylene (PTFE), wax, gutta-percha, cavit, endofrost-pellets and cotton pellets) were exposed (2.5 h, 37°C) to Streptococcus mutans, oralis and Candida albicans suspensions. Bacterial adherence was quantified by using the fluorescence dye, Alamar Blue/resazurin, and an automated multifunctional reader. For quantification of fungal adherence the ATP-based bioluminescence approach was used. High relative fluorescence and luminescence intensities (>10,000), indicating high adhesion of streptococci and fungi were found for cotton and endofrost-pellets and low intensities (<5,000) for wax, gutta-percha, cavit and PTFE. The quantity of bacterial and fungal adhesion differed significantly between the assessed various sealing materials. In conclusion and within the limitations of this study, wax, gutta-percha, cavit and PTFE should be preferred as sealing materials.

Evaluation of the Antibacterial Potential of Liquid and Vapor Phase Phenolic Essential Oil Compounds against Oral Microorganisms

The aim of the present study was to determine the antibacterial activities of the phenolic essential oil (EO) compounds hinokitiol, carvacrol, thymol, and menthol against oral pathogens. Aggregatibacter actinomycetemcomitans, Streptococcus mutans, Methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia. coli were used in this study. The minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), bacterial growth curves, temperature and pH stabilities, and synergistic effects of the liquid and vapor EO compounds were tested. The MIC/MBC of the EO compounds, ranging from the strongest to weakest, were hinokitiol (40-60 μg/mL/40-100 μg/mL), thymol (100-200 μg/mL/200-400 μg/mL), carvacrol (200-400 μg/mL/200-600 μg/mL), and menthol (500-more than 2500 μg/mL/1000-more than 2500 μg/mL). The antibacterial activities of the four EO phenolic compound based on the agar diffusion test and bacterial growth curves showed that the four EO phenolic compounds were stable under different temperatures for 24 h, but the thymol activity decreased when the temperature was higher than 80°C. The combination of liquid carvacrol with thymol did not show any synergistic effects. The activities of the vaporous carvacrol and thymol were inhibited by the presence of water. Continual violent shaking during culture enhanced the activity of menthol. Both liquid and vaporous hinokitiol were stable at different temperatures and pH conditions. The combination of vaporous hinokitiol with zinc oxide did not show synergistic effects. These results showed that the liquid and vapor phases of hinokitiol have strong anti-oral bacteria abilities. Hinokitiol has the potential to be applied in oral health care products, dental materials, and infection controls to exert antimicrobial activity.

Impact of Type and Duration of Application of Commercially Available Oral Moisturizers on Their Antifungal Effects

PURPOSE

To examine the impact of oral moisturizer type and application time on antifungal effects.

MATERIALS AND METHODS

Seventeen oral moisturizers (7 liquids, 10 gels) and amphotericin B (AMPH-B) were tested. Antifungal effects were evaluated with newly opened moisturizer samples (0 hour) and with samples incubated for 8 hours to simulate contact during sleep. Candida albicans samples (10⁸ cells/ml) were placed into cylindrical holes in 50% trypticase soy agar plates. Antifungal effects were evaluated based on growth-inhibitory zones after 24 hours. Equal quantities of moisturizers showing growth-inhibitory zones were mixed as additional samples. The effects of moisturizer type and application time on growth-inhibitory zones were evaluated with ANOVA. Growth-inhibitory zone sizes were compared with multiple comparisons.

RESULTS

Growth-inhibitory zones were found with two liquids, one gel, moisturizer mixtures, and AMPH-B. Significant differences in antifungal effects were found among different moisturizer types and between the 0- and 8-hour groups. The growth-inhibitory zones of the 8-hour group were significantly smaller than those of the 0-hour group. In both the 0- and 8-hour groups, the growth-inhibitory zones of the liquid-gel mixtures were significantly larger than those of other moisturizer types, and were the same size as those of AMPH-B at two concentrations (1.25 and 2.5 μg/ml). Growth-inhibitory zones of individual moisturizers and liquid-liquid mixtures were the same size as those of lower AMPH-B concentrations (0.16, 0.31, and 0.63 μg/ml).

CONCLUSION

Our findings suggest that mixing liquid and gel moisturizers improves their antifungal efficiency.

Phytochelators Intended for Clinical Use in Iron Overload, Other Diseases of Iron Imbalance and Free Radical Pathology

Iron chelating drugs are primarily and widely used in the treatment of transfusional iron overload in thalassaemia and similar conditions. Recent in vivo and clinical studies have also shown that chelators, and in particular deferiprone, can be used effectively in many conditions involving free radical damage and pathology including neurodegenerative, renal, hepatic, cardiac conditions and cancer. Many classes of phytochelators (Greek: phyto (φυτό)—plant, chele (χηλή)—claw of the crab) with differing chelating properties, including plant polyphenols resembling chelating drugs, can be developed for clinical use. The phytochelators mimosine and tropolone have been identified to be orally active and effective in animal models for the treatment of iron overload and maltol for the treatment of iron deficiency anaemia. Many critical parameters are required for the development of phytochelators for clinical use including the characterization of the therapeutic targets, ADMET, identification of the therapeutic index and risk/benefit assessment by comparison to existing therapies. Phytochelators can be developed and used as main, alternative or adjuvant therapies including combination therapies with synthetic chelators for synergistic and or complimentary therapeutic effects. The development of phytochelators is a challenging area for the introduction of new pharmaceuticals which can be used in many diseases and also in ageing. The commercial and other considerations for such development have great advantages in comparison to synthetic drugs and could also benefit millions of patients in developing countries.

Evaluation physical characteristics and comparison antimicrobial and anti-inflammation potentials of dental root canal sealers containing hinokitiol in vitro

Hinokitiol displays potent antimicrobial activity. It has been used in toothpaste and oral-care gel to improve the oral lichen planus and reduce halitosis. The aim of this study was to evaluate the antimicrobial activity of 3 different dental root canal sealers with hinokitiol (sealers+H) and their physical and biological effects. AH Plus (epoxy amine resin-based, AH), Apexit Plus (calcium-hydroxide-based, AP), and Canals (zinc-oxide-eugenol-based, CA), were used in this study. The original AH and CA exhibited strong anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity, but AP did not. The setting time, working time, flowability, film thickness, and solubility of each sealer+0.2%H complied with ISO 6876:2001. CA+0.2%H exhibited high cytotoxicity, but the others sealers+0.2%H did not. Because hinokitiol combined with Zn²⁺ in CA creates a synergistic effect. The physical tests of AP+0.5%–1%H complied with ISO 6876:2001, improved antimicrobial activity, inhibited inflammation genes cyclooxygenase-2 (COX-2) and hypoxia-inducible factor-1α (HIF-1α) mRNA in MG-63 cells and human gingival fibroblasts (HGF), and down-regulated lysyl oxidase (LOX) mRNA of HGF. In summary, AH and CA demonstrated strong antimicrobial activity, but AP did not. Application of hinokitiol increases AH anti-MRSA activity should less than 0.2% for keep well flowability. AP+0.5%–1% hinokitiol exhibited strong physical, antibacterial, and anti-inflammation potentials, and inhibited S. aureus abscess formation. Applying an appreciable proportion of hinokitiol to epoxy-amine-resin-based and calcium-hydroxide-based root canal sealers is warranted, but the enhanced cytotoxicity and synergistic effect must be considered.