Effects of Cistus-tea on bacterial colonization and enzyme activities of the in situ pellicle

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.

In Vitro Antimicrobial and Antibiofilm Properties and Bioaccessibility after Oral Digestion of Chemically Characterized Extracts Obtained from Cistus × incanus L., Scutellaria lateriflora L., and Their Combination

Periodontal diseases are oral inflammatory diseases ranging from gingivitis to chronic periodontitis. Porphyromonas gingivalis is one of the major pathogens responsible for severe and chronic periodontitis. Plant extracts with antimicrobial activity could be considered possible alternatives to chlorhexidine, an antiseptic substance used in oral hygiene thatcan cause bacteria resistance. Here, two commercial extracts obtained from Cistus × incanus L. and Scutellaria lateriflora L. were chemically characterized usingUltra-High-Performance Liquid Chromatography (UHPLC) coupled with a Q-Exactive Hybrid Quadrupole Orbitrap Mass Spectrometer. The extracts were studied for their bioaccessibility after simulated in vitro oral digestion, their antimicrobial activity against P. gingivalis, their protective effects against cellular invasion by P. gingivalis, and their antibiofilm activity. The extracts were found to contain very complex mixtures of polyphenols, which were quite stable after in vitro simulated oral digestion and demonstrated mild, dose-dependent inhibitory activity against P. gingivalis growth. This activity increased with the combination of the two extracts. Moreover, the combination of the extracts induced a reduction in P. gingivalis HaCaT invasiveness, and the reduction in biofilm came to around 80%. In conclusion, a combination of C. incanus and S. lateriflora showed promising effects useful in the treatment of gingivitis.

Comparative Evaluation of Polyphenol Contents and Biological Activities of Five Cistus L. Species Native to Turkey

In this study phytochemical compounds and antioxidant capacity, cytotoxic, antimicrobial and anti-biofilm activities of hydroethanolic extracts of five Cistus species (C. creticus L., C. laurifolius L., C. monspeliensis L., C. parviflorus Lam. and C. salviifolius L.) distributed in Turkey were investigated. (+)-catechin, epigallocatechin gallate, quercetin-3-O-rutinoside, quercetin-3-O-glucoside, kaempferol-3-O-glucoside, luteolin were detected in different amounts. Strongest antioxidant capacities were observed with C. creticus, and C. parvifolius (0.476 and 0.452, respectively). Minimum inhibitory concentrations (MIC) of the extracts were determined between 32 and 128 μg/mL against different bacteria and Candida strains. C. monspeliensis and C. laurifolius extracts were inhibited the biofilm production levels of three Gram-negative bacteria (E. coli, S. enterica, P. aeruginosa), two Gram-positive bacteria (S. aureus, B. subtilis) and three Candida strains (C. albicans, C. parapsilosis, C. krusei). C. creticus extract showed strongest cytotoxic activity against human breast adenocarcinoma (MCF-7) and prostate cell lines (PC-3) (IC₅₀ : 14.04±2.78 μg/mL and 34.04±2.74 μg/mL, respectively) among all plants tested.

The antimicrobial effect of Rosmarinus officinalis extracts on oral initial adhesion ex vivo

Objective

In the last few decades, there has been a growing worldwide interest in the use of plant extracts for the prevention of oral diseases. The main focus of this interest lies in the identification and isolation of substances that limit the formation of microbial biofilm which plays a major role in the development of caries, periodontitis, and peri-implantitis. In this clinical ex vivo study, we investigated the antimicrobial effects of Rosmarinus officinalis extract against oral microorganisms within in situ initial oral biofilms.

Materials and methods

Initial in situ biofilm samples (2 h) from six healthy volunteers were treated ex vivo with R. officinalis extract at concentrations of 20 mg/ml and 30 mg/ml. The number of viable bacterial cells was determined by counting the colony-forming units. All surviving bacteria were isolated in pure cultures and identified using MALDI-TOF and biochemical testing procedures. Additionally, live/dead staining in combination with epifluorescence microscopy was used for visualizing the antimicrobial effects in the initial biofilms.

Results

The number of colony-forming units in the R. officinalis–treated biofilms was significantly lower than in the untreated controls (p < 0.001). The reduction range of log10 was 1.64–2.78 and 2.41–3.23 for aerobic and anaerobic bacteria, respectively. Regarding the bacterial composition, large intra- and interindividual variability were observed. Except for Campylobacter spp., the average amount of all bacterial taxa was lower after treatment with R. officinalis than in the untreated biofilms. A total of 49 different species were detected in the untreated biofilms, while only 11 bacterial species were detected in the R. officinalis–treated biofilms. Live/dead staining confirmed that the R. officinalis–treated biofilms had significantly lower numbers of surviving bacteria than the untreated biofilms.

Conclusions

The treatment with R. officinalis extract has a significant potential to eliminate microbial oral initial biofilms.

Clinical relevance

The results of this study encourage the use of R. officinalis extracts in biofilm control and thus in the treatment of caries and periodontitis as a herbal adjuvant to synthetic substances.

Antimicrobial Effects of Inula viscosa Extract on the In Situ Initial Oral Biofilm

Given the undesirable side effects of commercially used mouth rinses that include chemically synthesized antimicrobial compounds such as chlorhexidine, it is essential to discover novel antimicrobial substances based on plant extracts. The aim of this study was to examine the antimicrobial effect of Inula viscosa extract on the initial microbial adhesion in the oral cavity. Individual test splints were manufactured for the participants, on which disinfected bovine enamel samples were attached. After the initial microbial adhesion, the biofilm-covered oral samples were removed and treated with different concentrations (10, 20, and 30 mg/mL) of an I. viscosa extract for 10 min. Positive and negative controls were also sampled. Regarding the microbiological parameters, the colony-forming units (CFU) and vitality testing (live/dead staining) were examined in combination with fluorescence microscopy. An I. viscosa extract with a concentration of 30 mg/mL killed the bacteria of the initial adhesion at a rate of 99.99% (log₁₀ CFU value of 1.837 ± 1.54). Compared to the negative control, no killing effects were determined after treatment with I. viscosa extract at concentrations of 10 mg/mL (log₁₀ CFU value 3.776 ± 0.831; median 3.776) and 20 mg/mL (log₁₀ CFU value 3.725 ± 0.300; median 3.711). The live/dead staining revealed a significant reduction (p < 0.0001) of vital adherent bacteria after treatment with 10 mg/mL of I. viscosa extract. After treatment with an I. viscosa extract with a concentration of 30 mg/mL, no vital bacteria could be detected. For the first time, significant antimicrobial effects on the initial microbial adhesion in in situ oral biofilms were reported for an I. viscosa extract.

A Review on Cistus sp.: Phytochemical and Antimicrobial Activities

Resistance to drugs is reaching alarming levels and is placing human health at risk. With the lack of new antimicrobials drugs, infectious diseases are becoming harder to treat. Hence, there is an increasing awareness of active phytochemicals with therapeutic functions. The tremendous research interest on the Cistus L. genus includes numerous plants used in traditional medicine by people living around the Mediterranean Sea, also resulted in some interesting discoveries and written literature. This review aimed at gathering scientific literature about Cistus species, describing phytochemical profiles and the various pharmacological activities. We also extensively reviewed the antimicrobial activities, including antiviral, antiparasitic, antifungal, and antibacterial potentials of Essential Oils (EO), raw extracts as well as isolated compounds. Mechanisms of action along with methods used are also investigated in this review. Considering the findings of the Cistus species extracts, this genus offers an adequate reserve of active phytochemicals since many have been used to create drugs. Therefore, this review work can serve society by providing a global view on Cistus L. sp. regarding pharmacological potentials and their chemical profiles.

Preventive Applications of Polyphenols in Dentistry-A Review

Polyphenols are natural substances that have been shown to provide various health benefits. Antioxidant, anti-inflammatory, and anti-carcinogenic effects have been described. At the same time, they inhibit the actions of bacteria, viruses, and fungi. Thus, studies have also examined their effects within the oral cavity. This review provides an overview on the different polyphenols, and their structure and interactions with the tooth surface and the pellicle. In particular, the effects of various tea polyphenols on bioadhesion and erosion have been reviewed. The current research confirms that polyphenols can reduce the growth of cariogenic bacteria. Furthermore, they can decrease the adherence of bacteria to the tooth surface and improve the erosion-protective properties of the acquired enamel pellicle. Tea polyphenols, especially, have the potential to contribute to an oral health-related diet. However, in vitro studies have mainly been conducted. In situ studies and clinical studies need to be extended and supplemented in order to significantly contribute to additive prevention measures in caries prophylaxis.

Evaluation of Anti-Biofilm Activity of Mouthrinses Containing Tannic Acid or Chitosan on Dentin In Situ

In contrast to enamel, dentin surfaces have been rarely used as substrates for studies evaluating the effects of experimental rinsing solutions on oral biofilm formation. The aim of the present in situ study was to investigate the effects of tannic acid and chitosan on 48-h biofilm formation on dentin surfaces. Biofilm was formed intraorally on dentin specimens, while six subjects rinsed with experimental solutions containing tannic acid, chitosan and water as negative or chlorhexidine as positive control. After 48 h of biofilm formation, specimens were evaluated for biofilm coverage and for viability of bacteria by fluorescence and scanning electron microscopy. In addition, saliva samples were collected after rinsing and analyzed by fluorescence (five subjects) and transmission electron microscopy (two subjects) in order to investigate the antibacterial effect on bacteria in a planktonic state and to visualize effects of the rinsing agents on salivary proteins. After rinsing with water, dentin specimens were covered by a multiple-layered biofilm with predominantly vital bacteria. In contrast, chlorhexidine led to dentin surfaces covered only by few and avital bacteria. By rinsing with tannic acid both strong anti-adherent and antibacterial effects were observed, but the effects declined in a time-dependent manner. Transmission electron micrographs of salivary samples indicated that aggregation of proteins and bacteria might explain the antiadhesion effects of tannic acid. Chitosan showed antibacterial effects on bacteria in saliva, while biofilm viability was only slightly reduced and no effects on bacterial adherence on dentin were observed, despite proteins being aggregated in saliva after rinsing with chitosan. Tannic acid is a promising anti-biofilm agent even on dentin surfaces, while rinsing with chitosan could not sufficiently prevent biofilm formation on dentin.

Results of a randomized controlled phase III trial: efficacy of polyphenol-containing cystus® tea mouthwash solution for the reduction of mucositis in head and neck cancer patients undergoing external beam radiotherapy

PURPOSE

To determine the effect of Cystus® tea (Naturprodukte Dr. Pandalis GmbH & Co. KG) as mouthwash compared to sage tea on oral mucositis in patients undergoing radio(chemo)therapy for head and neck cancer.

METHODS

In this randomized, prospective phase III study, 60 head and neck cancer patients with primary or postoperative radio(chemo)therapy were included between 04/2012 and 06/2014. They received either sage or Cystus® tea for daily mouthwash under therapy. Mucositis was scored twice a week following the Radiation Therapy Oncology Group and the European Organization for Research and Treatment Cancer (RTOG/EORTC) scoring system. Dental parameters were also recorded. Statistical evaluation of the primary endpoint was performed using t‑test and log rank test.

RESULTS

Data from 57 patients could be evaluated. Patient characteristics showed no significant difference between the two groups (n = 27 sage; n = 30 Cystus®). A total of 55 patients received the prescribed dose (60-66 Gy postoperative; 70-76.8 Gy primary). Mucositis grade 3 was observed in 23 patients (n = 11 sage; n = 12 Cystus®) and occurred between day 16 and 50 after start of therapy. There was no significant difference between the two groups in latency (p = 0.75) and frequency (p = 0.85) of the occurrence of mucositis grade 3. The self-assessment of the oral mucosa and the tolerability of the tea also showed no significant differences. Occurrence of dental pathologies appeared to increase over time after radiotherapy.

CONCLUSION

Cystus® and sage tea have a similar effect on the occurrence of radiation-induced mucositis regarding latency and incidence. Cystus® tea mouthwash solution is tolerated well and can be applied in addition to intensive oral care and hygiene along with the application of fluorides.

The effect of polyphenol-containing solutions on in situ biofilm formation on enamel and dentin

OBJECTIVES

To investigate the effects of Chinese gallnut extracts and pure tannic acid on in situ biofilm formation on enamel and dentin samples over 24 h.

METHODS

Bovine enamel and dentin samples were buccally fixed on maxillary splints. Six volunteers wore the splints for 24 h, and rinsed their mouths with tap water (control), 1% tannic acid- and 1% Chinese gallnut extracts-containing solution twice a day, 3 min after the splints were placed in the mouth and before night sleep. Live/dead staining was used for fluorescence microscopic (FM) visualization and quantification of bacteria viability of biofilms formed on enamel and dentin samples. Biofilm coverage was evaluated and recorded by FM and scanning electron microscopy (SEM). In addition, biofilms were analyzed by transmission electron microscopy (TEM). The Kruskal-Wallis test was used to analyze biofilm data.

RESULTS

Rinsing with tannic acid- and Chinese gallnut extracts-containing solutions significantly reduced in situ biofilm coverage on enamel and dentin samples (P < 0.05). The bacterial viability of biofilms formed on enamel samples was significantly reduced compared to the control (P < 0.05). TEM analysis revealed an increase in pellicle's electron density and thickness and only few or no bacteria adherent to the pellicle in the experimental samples.

CONCLUSIONS

Rinsing with tannic acid- and Chinese gallnut extracts-containing solutions can effectively inhibit in situ biofilm formation, modify the ultrastructure of biofilms on enamel and dentin surfaces and significantly reduce the bacterial viability of biofilm on enamel surfaces.

CLINICAL SIGNIFICANCE

Tannic acid- and Chinese gallnut extracts-containing solutions might be used for dental biofilm management.

Effects of Experimental Agents Containing Tannic Acid or Chitosan on the Bacterial Biofilm Formation in Situ

Chitosan and tannic acid are known for their antibacterial properties. In the present in-situ study, their antibacterial and anti-adherent effects on biofilm formation on enamel were investigated. Six subjects carried upper jaw splints with bovine enamel specimens, allowing in-situ biofilm formation. During the two-day trial, subjects rinsed with experimental solutions that contained either chitosan, tannic acid (pH = 2.5), tannic acid (pH = 7) or hydrochloric acid. Water served as the negative and chlorhexidine as the positive control. Rinsing occurred four or five times following two different rinsing protocols to investigate both the immediate and long-lasting effects. After 48 h of intraoral exposure, the dental plaque was stained with LIVE/DEAD^® BacLight, and fluorescence micrographs were evaluated by using the software ImageJ. The results were verified by scanning electron microscopy. Rinsing with chitosan resulted in little immediate antibacterial and anti-adherent effects but failed to show any long-lasting effect, while rinsing with tannic acid resulted in strong immediate and long-lasting effects. Except for a slightly lower antibacterial effect, the neutral solution of tannic acid was as good as the acidic solution. Hydrochloric acid showed neither an antibacterial nor an anti-adherent effect on dental biofilm formation. Experimental solutions containing tannic acid are promising anti-biofilm agents, irrespective of the pH values of the solutions. Chitosan, on the other hand, was not able to prevent biofilm formation.

Effect of fragaria vesca, hamamelis and tormentil on the initial bacterial colonization in situ

OBJECTIVE

The presentin situ study aims to examine the influence of the polyphenolic tea drugs fragaria vesca, hamamelis and tormentil on the initial oral bioadhesion.

DESIGN

Initial biofilm formation was performed on bovine enamel slabs which were carried intraorally by 12 subjects. After 1 min of intraoral pellicle formation, the subjects rinsed with fragaria vesca, tormentil (0.8 mg/8 mL) and hamamelis (0.2 mg/8 mL) for 10 min. Tap water served as negative control, 0.2 % CHX as positive control. The investigations took place on different days (wash-out: 2 days). Afterwards, fluorescence microscopy has been performed per test solution (n = 5) and per subject (n = 12) to visualize bacterial adhesion and glucan formation (8 h oral exposition) with DAPI, ConA and BacLight. Additionally, TEM was used to visualize the pellicle ultrastructure and expectorate samples. Statistical evaluation was carried out using the Kruskal-Wallis- (p < 0.5), Mann-Whitney U test (p < 0.5) and Bonferroni-Holm-correction (p < 0.1).

RESULTS

Rinsing with the polyphenolic tea extracts reduced significantly initial bacterial colonization (DAPI) compared to the negative control. There was no significant difference betweenfragaria vesca, hamamelis and tormentil. All solutions showed a reducing effect on the glucan formation. No significant difference was observed between fragaria vesca and CHX. Considerable alterations of the pellicle's ultrastructure manifested by an increase in thickness and electron density resulted from rinsing with the three polyphenolic aqueous extracts.

CONCLUSIONS

Fragaria vesca, hamamelis and tormentil significantly reduce initial bioadhesion and glucan formation in situ and are therefore recommended as adjuvant antibacterial oral therapeutics.

In-vitro antibacterial effect of tea polyphenols combined with common antibiotics on multidrug-resistant Klebsiella pneumoniae

BACKGROUND

To investigate the bactericidal effect of tea polyphenols on multidrug resistant Klebsiella pneumoniae and its antibacterial efficacy in combination with common antibiotics, and to explore its mechanism.

METHODS

The VITEK 2 Compact automatic microbial identification system was used to identify 20 strains of Klebsiella pneumoniae isolated from clinical isolates. The KB method was used to detect sensitivity of common drugs such as imipenem, piperacillin, piperacillin/tazobactam and cefepime, cefotaxime and ceftazidime; agar dilution method was used for detection of minimum inhibitory concentration (MIC) of tea polyphenols; the variation of the diameter of the antibacterial ring after different concentrations (0.25 MIC, 0.5 MIC) of tea polyphenols in combination with commonly used antibacterial drugs was detected to judge the feasibility of the inhibition of the multidrug-resistant Klebsiella pneumoniae by the combination of tea polyphenols and commonly used antibacterial drugs. Congo red and crystal violent staining was used to detect the impact on bacterial biofilm formation and extracellular mucus-like substance (slime).

RESULTS

The K-B values of 20 strains of Klebsiella pneumoniae against common antibiotics were 6-14 mm; the MIC of tea polyphenols against 20 strains of multi-drug resistant Klebsiella pneumoniae was 1024 ug/mL; 0.5 MIC tea polyphenols can increase the diameter of the bacteriostatic ring of imipenem, piperacillin, piperacillin/tazobactam, cefepime, cefotaxime and ceftazidime by 3-28 mm. Tea polyphenols at sub-inhibitory concentrations significantly inhibited the production of Klebsiella pneumoniae biofilm and extracellular mucus (slime).

CONCLUSIONS

Tea polyphenols could be used in combination with commonly used antibiotics (imipenem, piperacillin, piperacillin/tazobactam, cefepime, cefotaxime and ceftazidime) against multidrug-resistant Klebsiella pneumoniae. It has a synergistic bactericidal effect and affects the formation of bacterial outer membrane and the production of extracellular slime-like substances (slime).

Tea polyphenols: application in the control of oral microorganism infectious diseases

One of the most popular drinks worldwide, tea is rich in polyphenols and is beneficial to our health because it contributes to the prevention of many diseases. In the human oral cavity, there are more than 750 different species of bacteria living together within dental plaque. Some of the bacteria are pathogens that contribute to the development of oral diseases such as dental caries, periodontitis, pulpitis, mucosal disease, or halitosis through their virulence factors and their metabolites. Until now, many studies have reported that tea polyphenols (TPs) have evident inhibitory effects on some oral pathogenic microorganisms by suppressing pivotal steps of their pathogenic processes. The aim of this review is to summarize the effectiveness and mechanisms of TPs in inhibiting microorganisms, so as to provide new ideas for the prevention and treatment of oral diseases, and to contribute to the global dental public health.

Evaluation of Phenolic Compounds in Cistus creticus Bee Pollen from Greece. Antioxidant and Antimicrobial Properties

This study was carried out to evaluate the antioxidant properties of Greek endemic Cistus creticus L. (rock rose) bee pollen and define its phenolic compounds. In the framework of our scientific studies on Greek bee keeping products, we report herein our research on three Greek bee pollen samples from Cistus. Their pollinic spectra were obtained by Louveaux's quantitative microscopical analysis and it showed that one of them had Cistus sp. (Cistaceae) as abundant pollen (together with low percentage of Brassica sp. (Cruciferae). Throughout the chemical analysis of the extracts, several secondary metabolites of flavonoid structure have been identified as major components. Specifically, quercetin-7-rhamnoside (1), quercetin-3-neohesperidoside (2), kaempferol-3-neohesperidoside (3), myricetin-3-neohesperidoside (4), kaempferol-3-glucoside (5) and quercetin-3-glucoside (6) have been isolated and their structures were elucidated on the basis of spectral evidence. Moreover, the total phenolic and flavonoid content was estimated and the free radical scavenging activity was determined by DPPH and ABTS assays. The antimicrobial activity of the extracts was tested against six Gram-positive and -negative bacteria and three pathogenic fungi, and the butanol extract showed a very interesting broad antimicrobial profile (MIC 1.98•10−3 - 2.98•10−3 mg/ml) against all the assayed microorganisms.

Effect of Tannic Acid on the Protective Properties of the in situ Formed Pellicle

OBJECTIVES

In the present in situ/ex vivo study the impact of tannic acid on the erosion-protective properties of the enamel pellicle was tested. Additionally, the antiadherent and antibacterial effects of tannic acid were evaluated.

METHODS

The pellicle was formed in situ on bovine enamel samples fixed on individual splints worn by 6 subjects. Following 1 min of pellicle formation the volunteers rinsed for 10 min with tannic acid. After further oral exposure for 19 min, 109 min, and 8 h overnight, respectively, slabs were incubated in HCl ex vivo (pH 2.0, 2.3, 3.0) over 120 s. Subsequently, kinetics of calcium and phosphate release were measured photometrically. Samples after a 1-min fluoride mouth rinse as well as enamel samples with and without a 30-min in situ pellicle served as controls. Antiadherent effects were evaluated after a 1-min rinse with tannic acid and oral exposure of the slabs overnight. DAPI (4',6-diamidino-2-phenylindole) combined with concanavalin A staining and live/dead staining was used for fluorescence microscopic visualization and quantification of adherent bacteria and glucans. Modification of the pellicle's ultrastructure by tannic acid was evaluated by transmission electron microscopy (TEM).

RESULTS

Tannic acid significantly improved the erosion-protective properties of the pellicle in a pH-dependent manner. Bacterial adherence and glucan formation on enamel were significantly reduced after rinses with tannic acid as investigated by fluorescence microscopy. TEM imaging indicated that rinsing with tannic acid yielded a sustainable modification of the pellicle; it was distinctly more electron dense.

CONCLUSION

Tannic acid offers an effective and sustainable approach for the prevention of caries and erosion.

Effect of Inula viscosa on the pellicle's protective properties and initial bioadhesion in-situ

OBJECTIVES

The present in situ study investigated the effect of Inula viscosa tea on the pellicle's acid protective properties and on initial oral biofilm formation.

DESIGN

Biofilm formation was performed on bovine enamel slabs on individual maxillary splints. Following 1min of pellicle formation, eight subjects rinsed for 10min with Inula viscosa tea and the splints remained for 8h intraorally. Samples carried after 1-min rinsing with CHX (0.2%) or without rinse served as controls. BacLight™ staining, 4',6-diamidino-2-phenylindole (DAPI)-staining and fluorescence in situ hybridization (FISH) were used for fluorescence microscopic detection of adherent bacteria. For investigation of acid protective properties, three subjects rinsed for 10min with Inula viscosa tea after 1min pellicle formation and kept the splints intraorally for further 19min. Physiological 30-min pellicles and native enamel samples served as controls. After HCl incubation of the samples ex-vivo over 120s (pH 2.0, 2.3, 3.0) calcium- and phosphate release were quantified photometrically. Potential influences on the pellicle's ultrastructure by Inula viscosa tea were evaluated by transmission electron microscopy (TEM).

RESULTS

Application of Inula viscosa tea yielded a significant reduction of adherent bacteria on all enamel samples as detected by fluorescence microscopy. For calcium- and phosphate release no significant effect was recorded. TEM investigation indicated a modification of the pellicle's ultrastructure, but no enhanced protection against erosive noxae.

CONCLUSION

Rinsing with Inula viscosa tea influences the bacterial colonization on enamel in situ over 8h but has no impact on acid protective properties of the pellicle.

Natural Antimicrobials and Oral Microorganisms: A Systematic Review on Herbal Interventions for the Eradication of Multispecies Oral Biofilms

Oral diseases such as caries and periodontitis are mainly caused by microbial biofilms. Antibiotic therapy has reached its limits with regard to antimicrobial resistance, and new therapeutic measures utilizing natural phytochemicals are currently a focus of research. Hence, this systematic review provides a critical presentation of the antimicrobial effects of various medicinal herbs against in vitro, ex vivo, and in situ formed multispecies oral biofilms. Searches were performed in three English databases (PubMed, EMBASE, CAMbase) and the electronic archives of five German journals from the times of their establishment until October 10th, 2014, with the search terms “(plant extracts OR herbal extracts OR plant OR herb) AND (oral biofilm OR dental biofilm OR dental plaque OR oral disease OR dental disease).” The pooled data were assessed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA). Initially, 1848 articles were identified, out of which 585 full-text articles were screened, 149 articles were reevaluated for eligibility and finally, 14 articles met all inclusion criteria. The data of 14 reports disclosed enhanced antiadhesive and antibiofilm activity by the plant extracts obtained from Vitis vinifera, Pinus spp., Coffea canephora, Camellia sinensis, Vaccinium macrocarpon, Galla chinensis, Caesalpinia ferrea Martius, Psidium cattleianum, representative Brazilian plants and manuka honey. Overall, a positive correlation was revealed between herb-based therapies and elimination rates of all types of multispecies oral biofilms. In that context, integrating or even replacing conventional dental therapy protocols with herbal-inspired treatments can allow effective antimicrobial control of oral biofilms and thus, dental diseases.

Application of Plant Extracts for the Prevention of Dental Erosion: An in situ/in vitro Study

OBJECTIVES

Antiadherent and antibacterial effects of certain plant extracts have been proven to be beneficial in preventive dentistry. In the present in situ/in vitro crossover study, the impact of plant extracts rich in polyphenols on the erosion-protective properties of the in situ pellicle was evaluated.

METHODS

Individual splints were prepared for 12 subjects for intraoral exposure of bovine enamel specimens. Following formation of a 1-min pellicle, watery plant extracts (leaves of the wild form of Ribes nigrum, the wild form of Origanum as well as a combination of both) were administered for 10 min in situ. Alternatively, a mouth rinse with fluorides (Elmex Kariesschutz) was performed for 1 min. After further oral exposure for 19/28 min, respectively, slabs were removed and incubated with HCl in vitro over 120 s (pH 2, 2.3, 3). The resulting calcium and phosphate release was quantified photometrically. Slabs with and without a 30-min in situ pellicle served as controls. The modification of pellicle ultrastructure was evaluated by transmission electron microscopy (TEM).

RESULTS

Plant extracts modulated the erosion-protective properties of the native in situ pellicle in all test groups in a pH-dependent manner. The combination of R. nigrum leaves and Origanum enhanced the protective properties of the pellicle at all pH values; the administration of this preparation was comparable, yet superior, to the effect of the fluoridated mouth rinse. TEM images indicated that rinsing with R. nigrum leaves/Origanum yielded a distinctly thicker and more electron-dense pellicle.

CONCLUSION

The combination of certain plant extracts offers a novel approach to the complementary prevention of dental erosion.

Salivary amylase - The enzyme of unspecialized euryphagous animals

INTRODUCTION

Alpha-amylase (EC 3.2.1.1) is the most abundant enzyme in the saliva of man and of several vertebrates. In humans, salivary amylase is mainly formed in the parotid gland; its activity is of high inter-individual and intra-individual variability. The physiological functions of α-amylase have not yet been explored completely. It is well known that the enzyme cleaves the α-(1,4)-glycosidic bonds of polysaccharides. Furthermore it plays an important role in initial bioadhesion in man, facilitating carbohydrate metabolism and bacterial adherence at the tooth surface and therewith caries initiation. Nevertheless, it is still a matter of interest why humans have such high amounts of salivary amylase.

OBJECTIVE

The review presents an evolutionary approach by considering salivary amylase in the animal kingdom with special focus on mammalians divided into the three main nutritional types carnivores, herbivores, and omnivores; it was postulated that for most mammalian animals salivary α-amylase is essential.

RESULTS

The enzyme has been detected in saliva of some herbivores and many omnivorous animals, but not in pure carnivores. Focusing on ruminants, negligible levels or an absence of α-amylase was determined. Presence and activity probably differ depending on the species-specific diet. Animals feeding on unripe fruits, seeds, roots and bulbs exhibit higher activity of salivary α-amylase than species consuming ripe fruits, insects, and vertebrates.

CONCLUSION

In contrast to carnivores and most herbivores, omnivores have considerable amounts of amylase in their saliva. Though, the starch-digesting enzyme has been investigated well, the physiological function of amylase in saliva has not yet been explored completely. It can be hypothesized that nutritional habits affect expression of enzymes in the saliva of animals. It has to be verified, whether α-amylase is genetically or epigenetically determined. As a consequence of the development of agriculture, and following dietary changes, amylase can be recognized as a nutritional and evolutionary marker. Interdisciplinary evolutionary research might offer new perspectives for preventive dentistry.

Influence of the leaf content and herbal particle size on the presence and extractability of quantitated phenolic compounds in Cistus incanus herbal teas

A variety of Cistus incanus products and thereof a majority of herbal teas are offered by manufacturers despite a classification as Novel Food. For a re-evaluation of this legal status, a characterization of bioactive ingredients will provide data. These teas consist of various compositions of plant parts and particle sizes. Whereas some include high leaf contents with a small particle size, others mainly consist of woody stem parts. For the consumer it is of interest which product yields the highest concentrations of bioactive phenolic compounds in the final infusions. In this study, four commercially available samples were divided into leaves and stems. Additionally, one sample was reconstituted in three mixtures of these plant parts. The amount of wood was determined by cellulose concentration. The aim was to estimate the influence of the plant parts on the concentration of phenolic compounds, which were identified by LC-DAD-ESI-MS/MS and quantitated by LC-DAD. Furthermore, one herbal tea was separated into six fractions with different particle sizes to investigate the influence of particle size on the extractability of phenolic compounds. On basis of the results, the highest concentrations of bioactive compounds in the infusions were yielded when leafy parts with a small particle size were used for brewing.

New Insights into the Composition and Functions of the Acquired Enamel Pellicle

The acquired enamel pellicle (AEP) is a thin acellular film that forms on tooth surfaces upon exposure to the oral environment. It consists predominantly of salivary proteins, but also includes non-salivary-derived proteins, carbohydrates, and lipids. Since it is the interface between teeth and the oral environment, the AEP plays a key role in the maintenance of oral health by regulating processes including lubrication, demineralization, and remineralization and shaping the composition of early microbial flora adhering to tooth surfaces. Knowledge of the 3D structure of the AEP and how that correlates with its protective functions may provide insight into several oral pathological states, including caries, erosion, and periodontal disease. This review intends to update readers about the latest discoveries related to the formation, ultrastructure, composition, and functions of the AEP, as well as the future of pellicle research, with particular emphasis on the emerging role of proteomic and microscopy techniques in oral diagnosis and therapeutics.

Influence of a mouthwash containing hydroxyapatite microclusters on bacterial adherence in situ

OBJECTIVE

The aim of the present study was to investigate the efficacy of a new preparation in dental prophylaxis containing zinc-carbonate hydroxyapatite microclusters (Biorepair) for oral biofilm management.

METHODS AND MATERIALS

Initial biofilm formation was carried out in situ with bovine enamel slabs fixed to individual upper jaw splints worn by six subjects. Rinses with the customary preparation as well as with subfractions (hydroxyapatite microclusters in saline solution; liquid phase without particles) were adopted for 1 min in situ after 1 min of pellicle formation, and the bacterial colonization was recorded after 6 h and 12 h, respectively. Rinses with chlorhexidine served as a reference. The adherent microorganisms were quantified and visualized using DAPI staining and live-dead staining (BacLight). Furthermore, the effects on Streptococcus mutans bacteria were tested in vitro (BacLight).

RESULTS

Application of the customary preparation and of the separate components distinctly reduced the initial bacterial colonization of the enamel surface in situ as visualized and quantified with all techniques. After 12 h, 1.3 × 10(7) ± 2.0 × 10(7) bacteria/cm² were detected on unrinsed control samples with DAPI staining; 2.4 × 10(6) ± 3.3 × 10(6) after application of Biorepair (12 h after CHX-rinse; 1.3 × 10(5) ± 9.2 × 10(4)). Also, pure hydroxyapatite microclusters in saline solution (2.1 × 10(6) ± 3.0 × 10(6)) as well as the liquid phase without particles (5.1 × 10(5) ± 3.3 × 10(5)) reduced the amount of adherent bacteria. Furthermore, antimicrobial effects on S. mutans were observed in vitro.

CONCLUSION

The preparation is an effective compound for biofilm management in the oral cavity due to antiadherent and antibacterial effects.

CLINICAL RELEVANCE

The tested mouthrinse seems to be a reasonable amendment for dental prophylaxis.

Biology of Streptococcus mutans-derived glucosyltransferases: role in extracellular matrix formation of cariogenic biofilms

The importance of Streptococcus mutans in the etiology and pathogenesis of dental caries is certainly controversial, in part because excessive attention is paid to the numbers of S. mutans and acid production while the matrix within dental plaque has been neglected. S. mutans does not always dominate within plaque; many organisms are equally acidogenic and aciduric. It is also recognized that glucosyltransferases from S. mutans (Gtfs) play critical roles in the development of virulent dental plaque. Gtfs adsorb to enamel synthesizing glucans in situ, providing sites for avid colonization by microorganisms and an insoluble matrix for plaque. Gtfs also adsorb to surfaces of other oral microorganisms converting them to glucan producers. S. mutans expresses 3 genetically distinct Gtfs; each appears to play a different but overlapping role in the formation of virulent plaque. GtfC is adsorbed to enamel within pellicle whereas GtfB binds avidly to bacteria promoting tight cell clustering, and enhancing cohesion of plaque. GtfD forms a soluble, readily metabolizable polysaccharide and acts as a primer for GtfB. The behavior of soluble Gtfs does not mirror that observed with surface-adsorbed enzymes. Furthermore, the structure of polysaccharide matrix changes over time as a result of the action of mutanases and dextranases within plaque. Gtfs at distinct loci offer chemotherapeutic targets to prevent caries. Nevertheless, agents that inhibit Gtfs in solution frequently have a reduced or no effect on adsorbed enzymes. Clearly, conformational changes and reactions of Gtfs on surfaces are complex and modulate the pathogenesis of dental caries in situ, deserving further investigation.

Targeted immobilisation of lysozyme in the enamel pellicle from different solutions

Mouthwashes containing protective enzymes are required especially for patients suffering from xerostomia. The present study aimed to investigate the possibilities of modulating the immobilisation of lysozyme in the in situ pellicle layer. In situ formed pellicles were incubated in vitro for 10 min with various enzymatic buffer solutions containing lysozyme and additive enzymes such as transglutaminase or trypsin as well as polyphenolic compounds (cistus tea). After the rinses, the pellicle samples were incubated in collected whole saliva or in desorption solutions for 0, 20 and 40 min and the enzyme activities were measured. Furthermore, accumulation of lysozyme in the pellicle was visualised in ultrathin sections of the pellicle using the gold immunolabelling technique and transmission electron microscopy. Hen egg white lysozyme was accumulated in the in situ pellicle tenaciously. Up to 2.8-fold higher activities than in controls were observed. The addition of transglutaminase did not enhance the immobilisation of lysozyme activity, whereas the polyphenolic compound had no adverse effect. Accumulation of lysozyme in the acquired pellicle was confirmed by gold immunolabelling. Targeted and tenacious immobilisation of lysozyme in the acquired pellicle is possible. Poylphenolic compounds might be a relevant additive for mouthwashes containing lysozyme.

Bacterial colonization of enamel in situ investigated using fluorescence in situ hybridization

Oral biofilms are one of the greatest challenges in dental research. The present study aimed to investigate initial bacterial colonization of enamel surfaces in situ using fluorescence in situ hybridization (FISH) over a 12 h period. For this purpose, bovine enamel slabs were fixed on buccal sites of individual splints worn by six subjects for 2, 6 and 12 h to allow biofilm formation. Specimens were processed for FISH and evaluated with confocal laser-scanning microscopy, using probes for eubacteria, Streptococcus species, Veillonella species, Fusobacterium nucleatum and Actinomyces naeslundii. The number of adherent bacteria increased with time and all tested bacterial species were detected in the biofilm formed in situ. The general percentage composition of the eubacteria did not change over the investigated period, but the number of streptococci, the most frequently detected species, increased significantly with time (2 h: 17.7±13.8 %; 6 h: 20.0±16.6 %; 12 h: 24.7±16.1 %). However, ≤1 % of the surface was covered with bacteria after 12 h of biofilm formation in situ. In conclusion, FISH is an appropriate method for quantifying initial biofilm formation in situ, and the proportion of streptococci increases during the first 12 h of bacterial adherence.

Polyphenolic beverages reduce initial bacterial adherence to enamel in situ

OBJECTIVES

Polyphenols are antibacterial and anti-oxidative natural agents. The present in situ study aimed to investigate the effect of different polyphenolic beverages on initial bacterial adherence to enamel in the oral cavity.

METHODS

Initial biofilm formation was performed on bovine enamel specimens mounted buccally on individual upper jaw splints and carried by six subjects. After 1 min of pellicle formation, oral rinses with black tea, green tea, grape juice, Cistus tea or red wine were performed for 10 min. Afterwards the slabs were carried for another 19 or 109 min, respectively. Samples exposed to the oral fluids for 30 and 120 min served as controls. Following intraoral exposure, the slabs were rinsed with saline solution. The amount of adherent bacteria was determined with DAPI-staining (4',6-diamidino-2-phenylindole) and with fluorescence-in situ hybridization (FISH) of eubacteria and streptococci.

RESULTS

Rinses with all beverages reduced the amount of detectable bacteria. Lowest number of adherent bacteria was found following rinses with red wine, Cistus tea and black tea as measured with DAPI (up to 66% reduction of adherent bacteria vs. controls). Also FISH revealed significant impact of most tested beverages.

CONCLUSIONS

Rinses with certain polyphenolic beverages as well as consumption of these foodstuffs may contribute to prevention of biofilm induced diseases in the oral cavity.