Clinical anti-microbial efficacy of a new zinc citrate dentifrice

A randomized clinical study to examine the oral hygiene efficacy of a novel herbal toothpaste with zinc over a 6-month period

OBJECTIVES

This clinical investigation examined the effects of brushing with a test toothpaste containing natural ingredients, that is, clove (Syzgium Aromaticum), aloe vera (Aloe Barbadensis), amla (Emblica Officinalis), neem (Azadirachta Indica), tulsi (Ocimum Basillicum) and honey (from Apis Mellifera) along with zinc salts and fluoride in comparison with a dentifrice formulated with fluoride alone on dental plaque and gingivitis over a 6-month period.

MATERIALS AND METHOD

One hundred and eighty (180) subjects with mean plaque index scores greater than 1.5 (Turesky Modified Quigley Hein Plaque Index) and gingival index scores >1.0 (Loe and Silness gingival index) in good general health and who met other study criteria were enrolled in the clinical study. Subjects were evaluated for plaque and gingival index scores and were randomly assigned to perform twice-daily oral hygiene with either the test or the control toothpaste for the next 6 months. One hundred and fifty (150) subjects [test toothpaste (n = 72) and control toothpaste (n = 78)] completed the 6-month clinical study with evaluable data. Post-treatment assessments identical to baseline were conducted after 3-month and 6-month use of an assigned product after subjects refrained from oral hygiene for 12 h prior to each evaluation. Comparisons of the treatment groups with respect to baseline-adjusted gingival, plaque, and bleeding index scores at the follow-up examinations were performed using analyses of covariance (ANCOVA). All statistical tests of hypotheses were two-sided and employed a level of significance of p < 0.05.

RESULTS

No significant intergroup differences were noted between treatment groups for age and gender by two-sample t-test and chi-square analyses, respectively (p > 0.05). Furthermore, the treatment groups demonstrated no differences at baseline for plaque, gingival and bleeding index scores by a two-sample t-test (p > 0.05). At 3-month and 6-month examination, the test toothpaste exhibited progressive reductions in plaque, gingival and bleeding scores as compared to control toothpaste as showed by ANCOVA (p < 0.001). In comparison with the control, the test demonstrated reductions in 23.5%, 25.6%, and 73.3% for dental plaque, gingival index and bleeding index outcomes, respectively, at the final visit. Reductions in the frequencies of sites with higher clinical scores were noted over the study with more sites registering improvements in the test group than in the control group.

CONCLUSIONS

Routine oral hygiene with the test toothpaste formulated with herbal ingredients and zinc demonstrated a clinical adjunctive improvement in oral hygiene and parameters of gingival health as compared to brushing with a fluoride toothpaste.

Antimicrobial effects in oral microenvironments by a novel herbal toothpaste

Objective

This clinical study compared the antibacterial effects after brushing with a novel herbal toothpaste incorporating zinc [test] to a control fluoride toothpaste on anaerobic organisms, gram-negative bacteria and malodor bacteria of dental plaque, tongue scrapings and cheek surfaces.

Methods

This double-blind, two-cell study enrolled 44 adults [age range 19–63 years]. Subjects completed a 1-week washout and provided baseline oral samples i.e. dental plaque, tongue and cheek scrapings for microbiological analysis. Diluted samples for microbiological analyses were plated on agar to enumerate anaerobic organisms, gram-negative bacteria and malodor bacteria representing functional groups of organisms. Subjects were randomized to brush their teeth with either the test or control with the first brushing conducted under supervision in the dental clinic. Post-treatment samples were collected 12 h after 21 day hygiene with assigned toothpaste. After providing these samples, subjects brushed in the dental clinic with additional samples collected 4 h after brushing. Statistical analyses were conducted separately for each organism collected from each oral niche by t-test for within-treatment assessments and analysis of covariance (ANCOVA) for between-treatment comparisons.

Results

Treatment groups demonstrated no significant differences at baseline for anaerobic organisms, gram-negative bacteria and malodor bacteria in any oral niche (p > 0.05). The test demonstrated reductions between 42 and 68% for anaerobic bacteria in oral niches, 12 h after brushing with reductions increasing to 46–80%, 4 h after brushing. Similarly, the test demonstrated reductions between 49 and 61% for gram-negative bacteria of oral niches that increased to 54–69% at the 4 h post-brushing evaluation. Reductions in malodor organisms of 22–42% were noted 12 h after brushing that increased to 60–72%, 4 h after brushing.

Conclusions

In comparison to control, brushing with a novel herbal toothpaste demonstrated significant reductions in functional bacterial groups from distinct oral niches 12 h after brushing with additional microbial reductions 4 h after brushing.

In situ substrate-formed biofilms using IDODS mimic supragingival tooth-formed biofilms

This study aimed to compare the bacterial viability and diversity of a substrate-formed biofilm (SF-biofilm) in situ to a supragingival tooth-formed biofilm (TF-biofilm) in the same group of individuals. The impact of the device/disc position and toothbrushing during the formation of SF-biofilm was also assessed. Two tests were run. In test 1, 15 volunteers wore two hemi-splints carrying six discs of human enamel, glass, and hydroxyapatite for 2 days, and were instructed to not perform any oral hygiene measure. Biofilm samples were collected from the substrates and the contralateral tooth and were analysed using CLSM. In five volunteers, half of the biofilm present on the discs and their contralateral teeth were scraped and analysed using 16S  pyrosequencing. In test 2, the microscopic analysis was repeated only on the SF-biofilm samples, and the volunteers were allowed to brush their teeth. Multivariate analyses revealed that the donors had a significant effect on the composition of the biofilm, confirming its subject-dependent character. The bacterial composition of the SF-biofilm was similar to the TF-biofilm, with significant differential abundance detected in very few taxa of low abundance. The toothbrushing during the formation of SF-biofilm was the only factor that conditioned the thickness or bacterial viability.

Development of Epigallocatechin-3-gallate-Encapsulated Nanohydroxyapatite/Mesoporous Silica for Therapeutic Management of Dentin Surface

In dental clinic, unsatisfactory management of the dentin surface after dentin exposure often leads to the occurrence of dentin hypersensitivity and caries. Current approaches can occlude the tubules on the dentin surface to relieve dentin hypersensitivity; however, the blocked tubules are generally weak in combating daily tooth erosion and abrasion. Moreover, cariogenic bacteria, such as Streptococcus mutans, produce biofilm on the dentin surface, causing caries and compromising the tubules' sealing efficacy. To overcome this problem, the present study focused on establishing a versatile biomaterial, epigallocatechin-3-gallate-encapsulated nanohydroxyapatite/mesoporous silica nanoparticle (EGCG@nHAp@MSN), for therapeutic management of the dentin surface. The effectiveness of the biomaterial on dentinal tubule occlusion, including resistances against acid and abrasion, was evaluated by field-emission scanning electron microscopy (FESEM) and dentin permeability measurement. The inhibitory capability of the biomaterial on S. mutans biofilm formation was investigated by confocal laser scanning microscopy (CLSM), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony forming units (CFU) counts, and FESEM. Results demonstrated for the first time that the use of EGCG@nHAp@MSN on the dentin surface was capable of effectively occluding dentinal tubules, reducing dentin permeability, and achieving favorable acid- and abrasion-resistant stability. Furthermore, EGCG@nHAp@MSN held the capability to continuously release EGCG, Ca, and P, and significantly inhibit the formation and growth of S. mutans biofilm on the dentin surface. Thus, the development of EGCG@nHAp@MSN bridges the gap between multifunctional concept and dental clinical practice and is promising in providing dentists a therapeutic strategy for the management of the dentin surface to counter dentin hypersensitivity and caries.

Devices for In situ Development of Non-disturbed Oral Biofilm. A Systematic Review

Objective: The aim of this review was to assess the types of devices used for in situ development of oral biofilm analyzed microbiologically.

Materials and Methods: A systematic search of the literature was conducted to identify all in situ studies of oral biofilm which used an oral device; the Ovid MEDLINE and EMBASE databases complemented with manual search were used. Specific devices used to microbiologically analyze oral biofilm in adults were included. After reading of the selected full texts, devices were identified and classified according to the oral cavity zone and manufacturing material. The “ideal” characteristics were analyzed in every group.

Results: The search provided 787 abstracts, of which 111 papers were included. The devices used in these studies were classified as palatal, lingual or buccal. The last group was sub-classified in six groups based on the material of the device. Considering the analyzed characteristics, the thermoplastic devices and the Intraoral Device of Overlaid Disk-holding Splints (IDODS) presented more advantages than limitations.

Conclusions: Buccal devices were the most commonly used for the study of in situ biofilm. The majority of buccal devices seemed to slightly affect the volunteer's comfort, the IDODS being the closest to the “ideal” model.

Clinical Relevance: New devices for in situ oral biofilm microbiological studies should take into account the possible effect of their design on the volunteer's comfort and biofilm formation.

The intraoral device of overlaid disk-holding splints as a new in situ oral biofilm model

Objectives: To design a device that allows the formation of in situ oral biofilm with similar characteristics to those from the dental plaque, overcoming the limitations of previous devices. Study Design: The Intraoral Device of Overlaid Disk-holding Splints (IDODS) was designed and manufactured. To test its validity, five healthy adult volunteers wore them for two and four days allowing the biofilm to grow without any type of distortion. After each period, the thickness, vitality and structure of the formed biofilm were measured with a Confocal Laser Scanning Microscope (CLSM) in combination with a dual fluorescence solution. All volunteers filled out a Likert-type questionnaire to evaluate the device. Results: Mean bacterial vitality in the 2- and 4-day biofilms was 71% and 63%, respectively. Mean thicknesses were 21 µm and 28 µm, respectively. There was predominance in the open and heterogeneous structure whose complexity was ascending as the biofilm matured. The results obtained from the questionnaire were 2/5 in the influence in aesthetics, 3.4/5 in comfort, and 5/5 in ease of maintaining oral hygiene and withdrawal from the oral cavity. Conclusions: A biofilm with optimum characteristics was obtained by IDODS. Its use is associated with good aesthetic and comfort results and is absent of functional limitations, allowing optimal oral hygiene without altering the structure of the in situ oral biofilm.

Key words:Confocal Laser Scanning Microscope, fluorochromes, in situ, intraoral device, oral biofilm.

Effects of peroral supplementation of different forms of zinc on the ruminal mucosa of goat kids – a morphometric study

The aim of the study was to identify the effect of supplementation of various forms of zinc on the ruminal mucosa and dimensions of ruminal papillae in 6-month-old goat kids. The experimental period lasted from weaning to slaughter (4 months). All 20 kids divided into four groups of five animals, were fed with the same feeding dose, which was different only in the quantity and form of zinc. Control group was without additional zinc supplementation (group A), the other groups were supplemented with zinc in the form of ZnO (group B), zinc in the form of chelate (group C) and zinc in the form of lactate (group D). Samples for histopathological and morphometric examination were collected after the slaughter of all animals from the bottom of saccus ruminis ventralis everytime from the same place. Significant differences were reported within the comparison of the length of ruminal papillae between groups B and C (P = 0.026) and B and D (P = 0.040), within the comparison of the width of ruminal papillae between groups A and D (P = 0.020) and within the comparison of the intensity of keratinisation of the mucosa of ruminal papillae between groups A and B (P = 0.034), A and C (P = 0.038) and A and D (P = 0.001). Histopathological and morphometric examination of ruminal mucosa indicated that the ruminal papillae of kids supplemented with zinc in the form of ZnO (group B) were better developed compared to the other groups. This result indicates better utilisation of the supplemented zinc in the form of ZnO.

Effect of ZnCl2 on plaque growth and biofilm vitality

OBJECTIVE

The aim of this study was to evaluate the effects of ZnCl(2) on plaque-growth and vitality pattern of dental biofilm and to determine the optimum zinc concentration for the inhibition of plaque formation.

DESIGN

Data were collected from nine volunteers for whom a special-designed acrylic appliance was prescribed after a careful dental check up. The volunteers rinsed twice daily for 2min with ZnCl(2) of 2.5, 5, 10, 20mM as treatment and double distilled water (DDW) as control in respective assigned test weeks. The plaque index (PI) was assessed after 48h of appliance wearing. The glass discs with the adhered biofilm were removed from the splints and stained with two fluorescent dyes. The biofilm thickness (BT) and bacterial vitality of the whole biofilm as well as the mean bacterial vitality (BV) of the inner, middle and outer layers of biofilm were evaluated under confocal laser scanning microscope (CLSM).

RESULTS

PI, BT and BV of biofilms treated by various concentrations of ZnCl(2) were reduced significantly when compared with the DDW group (p<0.05). PI, BT and BV of the 2.5mM ZnCl(2) group was significantly higher than groups of 5, 10, 20mM ZnCl(2) (p<0.05). The mean BV of the 3 layers (inner, middle and outer layers) showed that 2.5mM ZnCl(2) was the lowest concentration to inhibit BV in the outer layer, 5mM was the lowest concentration to extend this inhibition of BV to the middle layer, and none of the concentrations investigated in this study has shown any effect on bacteria inhibition in the inner layer.

CONCLUSION

Zinc ions exhibited possible inhibitory effects on plaque formation, and have a promising potential to be used as an antibacterial agent in future dentifrices and mouthrinses.

Predation of oral pathogens by Bdellovibrio bacteriovorus 109J

Periodontal diseases are multifactorial infections elicited by a complex of primarily gram-negative bacteria that interact with host tissues and lead to the destruction of the periodontal structures. Bdellovibrio bacteriovorus is a gram-negative bacterium that preys upon other gram-negative bacteria. It was previously shown that B. bacteriovorus has an ability to attack and remove surface-attached bacteria or biofilms. In this study, we examined the host specificity of B. bacteriovorus strain 109J and its ability to prey on oral pathogens associated with periodontitis, including; Aggregatibacter actinomycetemcomitans, Eikenella corrodens, Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis and Tannerella forsythia. We further demonstrated that B. bacteriovorus 109J has an ability to remove biofilms of Ei. corrodens as well as biofilms composed of A. actinomycetemcomitans. Bdellovibrio bacteriovorus was able to remove A. actinomycetemcomitans biofilms developed on hydroxyapatite surfaces and in the presence of saliva, as well as to detach metabolically inactive biofilms. Experiments aimed at enhancing the biofilm removal aptitude of B. bacteriovorus with the aid of extracellular-polymeric-substance-degrading enzymes demonstrated that proteinase-K inhibits predation. However, treating A. actinomycetemcomitans biofilms with DspB, a poly-N-acetylglucosamine (PGA) -hydrolysing enzyme, increased biofilm removal. Increased biofilm removal was also recorded when A. actinomycetemcomitans PGA-defective mutants were used as host cells, suggesting that PGA degradation could enhance the removal of A. actinomycetemcomitans biofilm by B. bacteriovorus.