Electrolyzed Saline Targets Biofilm Periodontal Pathogens In Vitro.

Preventing the development and recurrence of periodontal diseases often includes antimicrobial mouthrinses to control the growth of the periodontal pathogens. Most antimicrobials are nonselective, targeting the symbiotic oral species as well as the dysbiosis-inducing ones. This affects the overall microbial composition and metabolic activity and consequently the host-microbe interactions, which can be detrimental (associated with inflammation) or beneficial (health-associated). Consequently, guiding the antimicrobial effect for modulating the microbial composition to a health-associated one should be considered. For such an approach, this study investigated electrolyzed saline as a novel rinse. Electrolyzed saline was prepared from sterile saline using a portable electrolysis device. Multispecies oral homeostatic and dysbiotic biofilms were grown on hydroxyapatite discs and rinsed daily with electrolyzed saline (EOS). Corresponding positive (NaOCl) and negative (phosphate-buffered saline) controls were included. After 3 rinses, biofilms were analyzed with viability quantitative polymerase chain reaction and scanning electron microscopy. Supernatants of rinsed biofilms were used for metabolic activity analysis (high-performance liquid chromatography) through measuring organic acid content. In addition, human oral keratinocytes (HOKs) were exposed to EOS to test biocompatibility (cytotoxicity and inflammation induction) and also to rinsed biofilms to assess their immunogenicity after rinsing. Rinsing the dysbiotic biofilms with EOS could reduce the counts of the pathobionts (>3 log10 Geq/mm2 reduction) and avert biofilm dysbiosis (≤1% pathobiont abundance), leading to the dominance of commensal species (≥99%), which altered both biofilm metabolism and interleukin 8 (IL-8) induction in HOKs. EOS had no harmful effects on homeostatic biofilms. The scanning electron micrographs confirmed the same. In addition, tested concentrations of EOS did not have any cytotoxic effects and did not induce IL-8 production in HOKs. EOS showed promising results for diverting dysbiosis in in vitro rinsed biofilms and controlling key periopathogens, with no toxic effects on commensal species or human cells. This novel rinsing should be considered for clinical applications.

Oral Biofilm Cryotherapy as a Novel Ecological Modulation Approach.

Oral cryotherapy is used in dentistry as a safe, simple, and low-cost treatment for a variety of oral lesions. It is well known for its ability to aid in the healing process. However, its effect on oral biofilms is unknown. As a result, the purpose of this study was to assess the effects of cryotherapy on in vitro oral biofilms. In vitro multispecies oral biofilms were grown on the surface of hydroxyapatite discs in symbiotic or dysbiotic states. CryoPen X+ was used to treat the biofilms, whereas untreated biofilms served as control. One set of biofilms was collected for study immediately after cryotherapy, whereas another group was reincubated for 24 h to permit biofilm recovery. Changes in biofilm structure were analyzed with a confocal laser scanning microscope (CLSM) and a scanning electron microscope (SEM), while biofilm ecology and community compositional changes were analyzed with viability DNA extraction and quantitative polymerase chain reaction (v-qPCR) analysis. One cryo-cycle immediately reduced biofilm load by 0.2 to 0.4 log10 Geq/mL, which increased with additional treatment cycles. Although the bacterial load of the treated biofilms recovered to the same level as the control biofilms within 24 h, the CLSM detected structural alterations. Compositional alterations were also detected by SEM, corroborating the v-qPCR findings that showed ≈≤10% incidence of pathogenic species compared to nontreated biofilms that encompassed ≈45% and 13% pathogenic species in dysbiotic and symbiotic biofilms, respectively. Spray cryotherapy showed promising results in a novel conceptual approach to the control of oral biofilms. Acting selectively by targeting oral pathobionts and retaining commensals, spray cryotherapy could modify the ecology of in vitro oral biofilms to become more symbiotic and prevent the evolution of dysbiosis without the use of antiseptics/antimicrobials.

Comparative 16S rRNA gene sequencing study of subgingival microbiota of healthy subjects and patients with periodontitis from four different countries.

AIM: To investigate the differences between the subgingival microbiota of healthy subjects (HS) and periodontitis patients (PP) from four different countries through a metagenomic approach. MATERIALS AND METHODS: Subgingival samples were obtained from subjects from four different countries. Microbial composition was analysed through high-throughput sequencing of the V3-V4 region of the 16S rRNA gene. The country of origin, diagnosis and clinical and demographic variables of the subjects were used to analyse the microbial profiles. RESULTS: In total, 506 subgingival samples were analysed: 196 from HS and 310 from patients with periodontitis. Differences in richness, diversity and microbial composition were observed when comparing samples pertaining to different countries of origin and different subject diagnoses. Clinical variables, such as bleeding on probing, did not significantly affect the bacterial composition of the samples. A highly conserved core of microbiota associated with periodontitis was detected, while the microbiota associated with periodontally HS was much more diverse. CONCLUSIONS: Periodontal diagnosis of the subjects was the main variable explaining the composition of the microbiota in the subgingival niche. Nevertheless, the country of origin also had a significant impact on the microbiota and is therefore an important factor to consider when describing subgingival bacterial communities.

[Innovative methods and developments in oral care. L-PRF: from evidence to clinical use]. / Serie: Innovatieve technieken en ontwikkelingen in de mondzorg. L-PRF: van evidence naar toepassingen in de praktijk.

Leukocyte- and platelet-rich fibrin (L-PRF) is a fully autologous biomaterial made from venous blood drawn from the patient. Due to its regenerative potency, antibacterial capacity, and analgesic activity, L-PRF can be used during surgical procedures as a sole biomaterial or as a bioactive additive along with other natural and synthetic biomaterials. There is sufficient scientific evidence available for applying L-PRF for various indications. The preparation protocol of L-PRF is simple, inexpensive and not time-consuming, making it possible to implement it in the daily practice. The type of centrifuge and blood collection tubes used, the settings of the centrifuge (rotation time and force) as well as the time between the different steps in the protocol have an influence on the biological and mechanical properties of L-PRF.

Impact of local and systemic antimicrobials on leukocyte- and platelet rich fibrin: an in vitro study.

The aim of this study was to evaluate the effect of local and systemic administration of antimicrobials to leukocyte- and platelet-rich fibrin (L-PRF). For part A, 16 tubes of venous blood were collected from each of eight systemically healthy subjects. Prior to blood centrifugation, 12 of the 16 tubes were injected with 0.125 ml, 0.25 ml or 0.50 ml metronidazole solution. One set of L-PRF membranes was used to assess the release of vascular endothelial growth factor AB, platelet-derived growth factor, transforming growth factor beta 1, and bone morphogenetic protein 2 at indicated time points. The metronidazole release over time by L-PRF membranes was also evaluated. The remaining L-PRF membranes were placed on the surface of agar plates inoculated with three different periodontal pathogens to determine their antibacterial activity. For part B, another six subjects were enrolled with three subjects taking 2 g amoxicillin and three subjects 500 mg metronidazole as prophylaxis prior to a periodontal treatment. Before and 2 h after consuming one of the prescribed antimicrobials, three tubes of blood were collected for preparing L-PRF membranes. These membranes were used to measure the antibacterial activity against periodontal pathogens. No statistically significant difference could be found in the release of growth factors between L-PRF membranes with and without incorporation of metronidazole solution. The release of metronidazole could be detected up to day 3, however with the highest concentration during the first 4 h. This concentration was dose dependent. The antibacterial capacity of L-PRF membranes increased significantly for both the systemic intake, and after the addition of metronidazole solution to the blood tubes before centrifugation, the latter again dose dependent. The antibacterial capacity of L-PRF against the periodontal pathogens tested can significantly be enhanced by the addition of antimicrobials, without disadvantage for the release of growth factors.

Impact of g force and timing on the characteristics of platelet-rich fibrin matrices.

Recently, new centrifugation protocols for the preparation of platelet-rich fibrin (PRF) have been introduced in an attempt to further improve the beneficial impact of these 2nd generation platelet concentrate membranes. This in-vitro study aimed to compare the biological and physical characteristics of three types of PRF membranes using two different centrifuges with adapted relative centrifugal forces (RCF): leucocyte- and platelet-rich fibrin, advanced platelet-rich fibrin, and advanced platelet-rich fibrin+. Release of growth factors, macroscopic dimensions, cellular content and mechanical properties of the respective membranes, prepared from blood of the same individual were explored. Furthermore, the impact of timing (blood draw-centrifugation and centrifugation-membrane preparation) was assessed morphologically as well as by electron microscopy scanning. No statistically significant differences amongst the three PRF modifications could be observed, neither in their release of growth factors or the cellular content, nor in clot/membrane dimensions. The difference between both centrifuges were negligible when the same g-force was used. A lower g-force, however, reduced membrane tensile strength. Timing in the preparation process had a significant impact. Adaptation of RCF only had a minimal impact on the final characteristics of PRF membranes.

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.

The OralChromaTM CHM-2: a comparison with the OralChromaTM CHM-1.

OBJECTIVES: Already decades ago, the diagnosis of halitosis was facilitated with the arrival of chair-side instruments to score the breath odor. These devices are used for a more objective assessment of halitosis compared with organoleptic scoring, but these too have their disadvantages. To overcome some of the drawbacks of the original model of the OralChromaTM (CHM-1), few years ago a second generation of this machine (CHM-2) was introduced. This study compared both devices in a clinical setting. MATERIALS AND METHODS: All records of the patients visiting a specialized halitosis consultation over a period of 5 years (2012-2017) were examined. The correlations of the OralChromaTM CHM-1 and CHM-2 with the organoleptic and Halimeter® measurements were analyzed. Additionally the sensitivity, specificity, and negative and positive predicted values were calculated. RESULTS: A total of 581 data points were included (CHM-1: 292, CHM-2: 289). The correlations between both models with the organoleptic measurements were not statistically significant different. The CHM-2 seemed superior to the CHM-1 in the quantification of dimethyl sulfide with a detection rate of 95% and 61%, respectively. Additionally, the CHM-2 was significantly more sensitive for dimethyl sulfide than the CHM-1. However the latter showed in turn a better sensitivity for hydrogen sulfide and methyl mercaptan. CONCLUSION: The CHM-2 showed a better sensitivity for dimethyl sulfide than its predecessor. However, its sensitivity for hydrogen sulfide and methyl mercaptan was worse. CLINICAL RELEVANCE: Dimethyl sulfide is the main volatile implicated in extra-oral blood-borne halitosis, this makes the OralChromaTM CHM-2 the instrument of choice when this is suspected.

L-PRF for increasing the width of keratinized mucosa around implants: A split-mouth, randomized, controlled pilot clinical trial.

BACKGROUND: This study aims to evaluate the use of the leukocyte- and platelet-rich fibrin (L-PRF) membranes in increasing the width of the keratinized mucosa (KM) around implants. MATERIAL AND METHODS: Eight patients in need for bilateral widening of the KM around implants in the lower jaw were recruited for a spit-mouth randomized controlled trial. At the control site, a free gingival graft (FGG) was used, whereas at the other side (test), L-PRF membranes were applied. The primary outcome was the increase in width of KM around the implants. As secondary outcomes, the postoperative pain and surgical time were assessed. The follow-up period was 6 weeks. RESULTS: A significant increase in the total bucco-lingual width of KM in both groups was observed, with 1.3 mm ± 0.9 extra gain (P < .05) for the FGG sites. Shrinkage of the widened areas in this period was 32.1% at the test site and 23.6% at the control site. All values of the postoperative pain scores at the control site were higher than at the test site. The mean surgery time in the test and control group was 29.1 ± 4.8 and 48.1 ± 7.7 minutes, respectively. CONCLUSION: Within the limitations of this randomized controlled trial with split mouth design, it can be concluded that L-PRF can increase the width of KM around implants. Furthermore, the use of L-PRF results in a lower surgical time with less postoperative discomfort and pain for the patients in comparison to the FGG.

Healing of toothbrush-induced abrasions to keratinized mucosa of the palate in humans: A pilot study.

BACKGROUND AND OBJECTIVE: To the best of our knowledge, the healing time for toothbrush-induced gingival abrasions in humans has not yet been explored. The aim of this study was to evaluate the time needed to heal for toothbrush-induced abrasions of the keratinized mucosa of the palate. MATERIAL AND METHODS: In patients without, with mild periodontitis or with periodontitis, gingival abrasion lesions were induced at the keratinized mucosa of the palate by brushing up to 2 minutes. Healing as observed clinically was followed via calibrated digital photographs of the lesion after staining, every 24 hours until the lesion had resolved. In patients without or with only mild periodontitis, the healing time of lesions caused by 30 seconds and 1 minute of brushing was also recorded. RESULTS: Thirty-one participants (11 without or with mild periodontitis, 20 with periodontitis) met the inclusion criteria. In patients without or with mild periodontitis, the lesions induced by brushing for 2 minutes diminished by 48.7% of their original surface area within 24 hours. In patients with periodontitis the respective outcome was 45.4% (P = .87). Abrasions caused by 2 minutes of brushing needed more than 24 hours to heal completely. When decreasing the time exposed to trauma, fewer lesions were visible at baseline and the time needed to heal decreased. The subgroup of smokers was too small to evaluate any effect. CONCLUSION: The longer the exposure time of the keratinized mucosa of the palate to trauma, the more lesions were visible, the larger the abrasions were and the more time they needed to heal completely. More studies are needed to investigate the role of smoking, gingival biotype and to link these findings with gingival recessions.

Clinical concentrations of peroxidases cause dysbiosis in in vitro oral biofilms.

BACKGROUND AND OBJECTIVE: Little is known about the initiation of dysbiosis in oral biofilms, a topic of prime importance for understanding the etiology of, and preventing, periodontitis. The aim of this study was to evaluate the effect of different concentrations of crevicular and salivary peroxidase and catalase on dysbiosis in multispecies biofilms in vitro. MATERIAL AND METHODS: The spotting technique was used to identify the effect of different concentrations of myeloperoxidase, lactoperoxidase, erythrocyte catalase, and horseradish peroxidase in salivary and crevicular fluid on the inhibitory effect of commensals on pathobiont growth. Vitality-quantitative real-time PCR was performed to quantify the dysbiotic effect of the peroxidases (adjusted to concentrations found in periodontal health, gingivitis, and periodontitis) on multispecies microbial communities. RESULTS: Agar plate and multispecies ecology experiments showed that production of hydrogen peroxide (H2 O2 ) by commensal bacteria decreases pathobiont growth and colonization. Peroxidases at concentrations found in crevicular fluid and saliva neutralized this inhibitory effect. In multispecies communities, myeloperoxidase, at the crevicular fluid concentrations found in periodontitis, resulted in a 1-3 Log increase in pathobionts when compared with the crevicular fluid concentrations found in periodontal health. The effect of salivary lactoperoxidase and salivary myeloperoxidase concentrations was, in general, similar to the effect of crevicular myeloperoxidase concentrations. CONCLUSIONS: Commensal species suppress pathobionts by producing H2 O2 . Catalase and peroxidases, at clinically relevant concentrations, can neutralize this effect and thereby can contribute to dysbiosis by allowing the outgrowth of pathobionts.

Dysbiotic Biofilms Deregulate the Periodontal Inflammatory Response.

Periodontal diseases originate from a dysbiosis within the oral microbiota, which is associated with a deregulation of the host immune response. Although little is known about the initiation of dysbiosis, it has been shown that H2O2 production is one of the main mechanisms by which some commensal bacteria suppress the outgrowth of pathobionts. Current models emphasize the critical nature of complex microbial biofilms that form unique microbial ecologies and of their change during transition from health (homeostatic) to disease (dysbiotic). However, very little is known on how this alters their virulence and host responses. The objective of this study was to determine differences in virulence gene expression by pathobionts and the inflammatory host response in homeostatic and dysbiotic biofilms originating from the same ecology. Quantitative polymerase chain reaction was performed to quantify the pathobiont outgrowth. Expression analysis of bacterial virulence and cellular inflammatory genes together with cytokine enzyme-linked immunosorbent assays were used to detect differences in bacterial virulence and to analyze potential differences in inflammatory response. An increase in pathobionts in induced dysbiotic biofilms was observed compared to homeostatic biofilms. The main virulence genes of all pathobionts were upregulated in dysbiotic biofilms. Exposure of these dysbiotic biofilms to epithelial and fibroblast cultures increased the expression of interleukin (IL)-6, IL-1ß, tumor necrosis factor-α, and matrix metalloprotease 8, but especially the chemokine CXCL8 (IL-8). Conversely, homeostatic and beneficial biofilms had a minor immune response at the messenger RNA and protein level. Overall, induced dysbiotic biofilms enriched in pathobionts and virulence factors significantly increased the inflammatory response compared to homeostatic and commensal biofilms.

Can degradation products released from dental implants affect peri-implant tissues?

This study aimed to assess the literature available on the effects, on peri-implant tissues, of degradation products released from dental implants as a consequence of therapeutic treatment for peri-implantitis and/or of wear-corrosion of titanium. A literature review of the PubMed medline database was performed up to December 31, 2016. The following search terms were used: "titanium wear and dental implant"; "titanium corrosion and dental implant"; "bio-tribocorrosion"; "peri-implantitis"; "treatment of peri-implantitis"; "titanium particles release and dental implant"; and "titanium ion release and dental implant". The keywords were applied to the database in different combinations without limits of time period or type of work. In addition, the reference lists of relevant articles were searched for further studies. Seventy-nine relevant scientific articles on the topic were retrieved. The results showed that pro-inflammatory cytokines, infiltration of inflammatory response cells and activation of the osteoclasts activity are stimulated in peri-implant tissues in the presence of metal particles and ions. Moreover, degenerative changes were reported in macrophages and neutrophils that phagocytosed titanium microparticles, and mutations occurred in human cells cultured in medium containing titanium-based nanoparticles. Debris released from the degradation of dental implants has cytotoxic and genotoxic potential for peri-implant tissues. Thus, the amount and physicochemical properties of the degradation products determine the magnitude of the detrimental effect on peri-implant tissues.

Influence of tongue brushing and scraping on the oral microflora of periodontitis patients.

OBJECTIVE: To examine the effect of tongue cleaning with a tongue scraper (TS) or toothbrush (TB) in patients with periodontitis. BACKGROUND: The tongue is a possible reservoir for bacterial (re)colonization of the periodontal tissues in patients with periodontitis. To date, it is not known what the influence of tongue cleaning is on the tongue coating of patients with periodontitis. MATERIAL AND METHODS: Eighteen systemically healthy, untreated moderate to severe adult patients with periodontitis with some degree of tongue coating were randomly assigned to the use of a TS or TB for cleaning the tongue. Microbial load of the saliva and tongue dorsum, amount of tongue coating and patient perception about tongue cleaning were studied at baseline and 2 weeks later. RESULTS: Two weeks of tongue cleaning with either a TB or a TS, did not influence the microbiological counts, neither in the saliva, nor in the tongue coating, even though tongue coating was significantly less. The patients themselves experienced no differences in breath odour or taste sensation after 2 weeks of tongue cleaning; however, they felt that their tongue was cleaner at the end of the study compared to baseline. No differences could be detected between the uses of a TS vs a TB. CONCLUSION: In patients with periodontitis, tongue cleaning does not influence the bacterial load in the saliva or on the tongue dorsum.

Periodontal screening and referral behaviour of general dental practitioners in Flanders.

OBJECTIVES: The objective of this study was to investigate the screening and referral behaviour of Flemish dentists concerning periodontitis and more specific, the use of the Dutch Periodontal Screening Index (DPSI). MATERIALS AND METHODS: An online questionnaire was electronically distributed through the different professional dental societies. It consisted of two parts: the first aimed at describing the profile of the dentist. The second part inquired the screening method, when this was applied, periodontal risk factors and referral behaviour. RESULTS: One thousand fifty dentists attended to the questionnaire. One hundred fifty-nine questionnaires were excluded since they did not match the target audience. Sixty-four percent of Flemish dentists used DPSI as a periodontal screening method, 28% screened based on probing pocket depth, 4% used solely radiographs and 4% had no screening method at all. The usage of DPSI is influenced by the year of graduation: the longer the dentists were graduated, the less they used DPSI. No influence of sex, education centre and location was found. Referral behaviour is influenced by different patient- and dentist-related factors. CONCLUSIONS: Regarding the screening behaviour, there seems a consensus among Flemish dentists that a periodontal probe should be used. For referral, there is no consensus about if and when to refer to a specialist. CLINICAL RELEVANCE: It is encouraging that 92% of the Flemish general dental practitioners use a probe when screening for periodontitis. However, DPSI is mainly used by younger dentists. An effort should be made to encourage all dentists to use this, so that in every patient, periodontitis can be detected timely, securing the best treatment outcome.

Synergistic interactions between corrosion and wear at titanium-based dental implant connections: A scoping review.

Two-piece implant systems are mainly used in oral implantology involving an osseointegrated implant connected to an abutment, which supports prosthetic structures. It is well documented that the presence of microgaps, biofilms and oral fluids at the implant-abutment connection can cause mechanical and biological complications. The aim of this review paper was to report the degradation at the implant-abutment connection by wear and corrosion processes taking place in the oral cavity. Most of the retrieved studies evaluated the wear and corrosion (tribocorrosion) of titanium-based materials used for implants and abutments in artificial saliva. Electrochemical and wear tests together with microscopic techniques were applied to validate the tribocorrosion behavior of the surfaces. A few studies inspected the wear on the inner surfaces of the implant connection as a result of fatigue or removal of abutments. The studies reported increased microgaps after fatigue tests. In addition, data suggest that micromovements occurring at the contacting surfaces can increase the wear of the inner surfaces of the connection. Biofilms and/or glycoproteins act as lubricants, although they can also amplify the corrosion of the surfaces. Consequently, loosening of the implant-abutment connection can take place during mastication. In addition, wear and corrosion debris such as ions and micro- and nanoparticles released into the surrounding tissues can stimulate peri-implant inflammation that can lead to pathologic bone resorption.

Inhibition of multi-species oral biofilm by bromide doped bioactive glass.

Bioactive glass is an attractive biomaterial that has shown excellent osteogenic and angiogenic effects for oral bone repairing procedures. However, anti-biofilm potential related to such biomaterial has not been completely validated, mainly against multi-species biofilms involved in early tissue infections. The aim of the present study was to evaluate the anti-biofilm effect of 58 S bioactive glass embedding calcium bromide compounds at different concentrations. Bioactive glass free or containing 5, or 10 wt % CaBr2 was synthesized by alkali sol-gel method and then characterized by physco-chemical analyses and scanning electron microscopy (SEM). Then, samples were tested by microbiological assays using optical density, real time q-PCR, and SEM. Bioactive glass particles showed accurate chemical composition and an angular shape with a bimodal size distribution ranging from 0.6 to 110 µm. The mean particle size was around 29 µm. Anti-biofilm effect was recorded for 5 wt % CaBr2 -doped bioactive glass against S. mitis, V. parvula, P. gingivais, S. gordoni, A. viscosus, F, nucleatum, P. gingivais. F. nucleatum, and P. gingivalis. Such species are involved in the biofilm structure related to infections on hard and soft tissues in the oral cavity. The incorporation of calcium bromide into bioactive glass can be a strategy to enhance the anti-biofilm potential of bioactive glasses for bone healing and infection treatment. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1994-2003, 2017.

Clinical effects of probiotics containing Bacillus species on gingivitis: a pilot randomized controlled trial.

BACKGROUND AND OBJECTIVE: Lactobacillus spp. and bifidobacteria are the most frequently used probiotics in oral health research. However, although probiotic effects have been suggested for other genera, such as bacilli, no trials are available to describe the effect of bacilli probiotics on gingivitis in humans. The aim of the present study was to evaluate the clinical effects of a bacilli-containing toothpaste, a mouthrinse and a toothbrush cleaner versus a placebo in patients with generalized gingivitis. MATERIAL AND METHODS: In this double-blind placebo-controlled randomized clinical trial, nonsmoking, systemically healthy patients with generalized gingivitis were included. They used a placebo or an experimental probiotic Bacillus subtilis-, Bacillus megaterium- and Bacillus pumulus-containing toothpaste, mouthrinse and toothbrush cleaner for 8 wk. Primary outcome measures of interest were plaque and gingivitis index, and the secondary outcome measures were pocket probing depth and bleeding on probing. RESULTS: Twenty male and 20 female patients were randomized over the two groups. All participants could be included in the final analysis. Although plaque and gingivitis indices were significantly reduced after 8 wk, no intergroup differences could be found at any time point. Also, for the secondary outcome measure, intragroup but no intergroup differences could be detected. No harm or unintended effects were reported by the patients after using the study products. CONCLUSIONS: This study did not show any statistically significant differences between a placebo and a bacilli-containing toothpaste, mouthrinse and toothbrush cleaner on gingivitis parameters.

In vivo electrical application on titanium implants stimulating bone formation.

BACKGROUND AND OBJECTIVE: The aim of the present in vivo study was to measure the bone implant contact area after electrical stimulation of dental implants. MATERIAL AND METHODS: Ninety titanium dental implants (6 mm × 11.5 mm) with a smooth surface were placed in six male Beagle dogs and then the implant-bone interfaces was assessed by histological analyses after 7 and 15 d. The 12-mo-old dogs, with a weight of 15 kg, were randomly divided into two groups based on the duration of bone healing: 7 and 15 d. Also, implants were divided into three groups based on electrical stimulation: group A, 10 µA; group B, 20 µA; and group C, control group. The electrical current was applied by an electrical device coupled to the implant connection. RESULTS: After 7 d of electrical stimulation, no statistical differences in bone-implant interface contact area were observed. However, a significantly higher bone-implant interface contact area was recorded for group B than for groups A and C (p < 0.01) after 15 d. No statistical difference was observed between groups A and C (p > 0.05). CONCLUSION: The electrical stimulation of dental implants can generate a larger area of bone-implant interface contact as a result of bone formation. Factors such as different electrical current intensity and duration should be studied in further work to clarify the potential of this method.

Lack of Buffering by Composites Promotes Shift to More Cariogenic Bacteria.

Secondary caries (SC) remains a very important problem with composite restorations. The objectives of this study were to test the acid-buffering ability of several restorative materials and to evaluate whether buffering of the restorative material has an impact on the microbial composition of the biofilm. Disk-shaped specimens of conventional composite, composite with surface prereacted glass-ionomer filler particles (so-called giomer), glass-ionomer cement (GIC), amalgam, and hydroxyapatite (HAp) (control) were exposed to aqueous solutions with pH 4, 5, 6, and 7 and to the medium containing bacteria-produced acids, and pH changes were recorded over several days. Next, material specimens were immersed in bacterial growth medium with pH adjusted to 5. After a 24-h incubation, the extracts were collected and inoculated with a cariogenic (Streptococcus mutans) and a noncariogenic (Streptococcus sanguinis) species. The bacterial growth was monitored both in a single-species model by spectrophotometry and in a dual-species model by viability quantitative polymerase chain reaction. Amalgam and HAp showed the strongest acid-buffering ability, followed by the GIC and the giomer, while the conventional composite did not exhibit any buffering capacity. Furthermore, due to the lack of acid-buffering abilities, composite was not able to increase the pH of the medium (pH 5), which, in the absence of antibacterial properties, allowed the growth of S. mutans, while the growth of S. sanguinis, a less aciduric species, was completely inhibited. A similar effect was observed when bacteria were cultured together: there was a higher percentage of S. mutans and lower percentage of S. sanguinis with the conventional composite than with other materials and HAp. In conclusion, conventional composites lack the ability to increase the local pH, which leads to the outgrowth of more acidogenic/aciduric bacteria and higher cariogenicity of the biofilm. Together with lack of antibacterial properties, lack of buffering may account for the higher susceptibility of composites to SC.