Dose-response effect of chlorhexidine on a multispecies oral biofilm formed on pure titanium and on a titanium-zirconium alloy

This study aimed to test the dose-response effect of chlorhexidine on multispecies biofilms formed on commercially pure titanium (cpTi) and titanium-zirconium (TiZr) alloy. Biofilms were formed on cpTi and TiZr discs and treated two times per day with five different chlorhexidine concentrations (0.12, 0.20, 0.50, 1, 2%). The biofilms were collected for microbiological, biochemical and microscopic analyses. The significance of differences among groups was evaluated by linear regression, ANOVA, Bonferroni and Tukey tests. The mean number of colony-forming units decreased as the chlorhexidine concentration increased for both cpTi and TiZr (p < 0.05). The maximum effect was observed with the 0.5% concentration. Confocal microscopy images suggested an increase in the number of dead bacterial cells with increased chlorhexidine concentration. The biofilm pH increased after chlorhexidine exposure (p < 0.05). Chlorhexidine showed an antimicrobial dose-response effect in controlling biofilm on cpTi and TiZr. 0.5% chlorhexidine can be used to achieve the maximum antimicrobial effect on both materials.

Clinical and microbiological effects of scaling and root planing, metronidazole and amoxicillin in the treatment of diabetic and non-diabetic subjects with periodontitis: A cohort study

AIM

To evaluate if non-diabetic subjects with periodontitis respond better than subjects with type 2 diabetes to the treatment protocol of scaling and root planing (SRP), metronidazole (MTZ) and amoxicillin (AMX).

MATERIAL AND METHODS

Diabetic and nondiabetic subjects with severe periodontitis received SRP + MTZ (400 mg/thrice a day [TID]) + AMX (500 mg/TID) for 14 days. Subgingival biofilm samples were analyzed by checkerboard DNA-DNA hybridization for 40 bacterial species. Subjects were monitored at baseline, 3, 6 and 12 months post-therapy.

RESULTS

Twenty-nine type 2 diabetics and 29 non-diabetic subjects participated of this study. Of the non-diabetics and diabetics, 68.9% and 75.9%, respectively, reached the clinical endpoint for treatment (≤4 sites with probing depth [PD] ≥5 mm) at 1 year post-therapy (p > 0.05). The diabetic group presented lower mean clinical attachment gain from baseline to 1 year post-therapy and higher mean proportions of the red and orange complexes than the non-diabetic group (p < 0.05).

CONCLUSIONS

Non-diabetic subjects with severe periodontitis did not respond better than type 2 diabetic subjects to the treatment protocol of SRP + MTZ + AMX, both in terms of achieving the clinical endpoint for treatment and of PD improvement. Diabetic subjects exhibited a slightly worse microbiological response and showed a healing process more associated with gingival recession than the non-diabetics.

Effects of different periodontal treatments in changing the prevalence and levels of Archaea present in the subgingival biofilm of subjects with periodontitis: A secondary analysis from a randomized controlled clinical trial

OBJECTIVE

The aim of this randomized double-blind and placebo-controlled study was to assess if periodontal treatment with or without systemic antibiotic would change the mean level of Archaea.

METHODS

Fifty-nine (59) subjects were randomly assigned to receive scaling and root planing (SRP) alone or combined with metronidazole (MTZ; 400 mg/TID) or either with MTZ and amoxicillin (AMX; 500 mg/TID) for 14 days. Clinical and microbiological examinations were performed at baseline and at 6 months post-SRP. Six subgingival plaque samples per subject were analysed for the presence and levels of Archaea using quantitative polymerase chain reaction.

RESULTS

Scaling and root planing alone or combined with MTZ or MTZ + AMX significantly reduced the prevalence of subjects colonized by Archaea at 6 months post-therapy, without significant differences among groups (P > .05). Both therapies led to a statistically significant decrease in the mean percentage of sites colonized by Archaea (P < .05). The MTZ and MTZ + AMX group had a significantly lower mean number of sites colonized by Archaea and lower levels of these micro-organisms at sites with probing depth ≥5 mm at 6 months compared with SRP group (P < .05).

CONCLUSION

Periodontal treatments including adjunctive MTZ or MTZ + AMX are more effective than mechanical treatment alone in reducing the levels and prevalence of sites colonized by Archaea in subjects with chronic periodontitis.

The ideal time of systemic metronidazole and amoxicillin administration in the treatment of severe periodontitis: study protocol for a randomized controlled trial

Background

The combination of systemic metronidazole (MTZ) and amoxicillin (AMX) with scaling and root planing (SRP) has shown to be an effective periodontal treatment. However, some essential issues associated with the use of these antibiotics remain unanswered, such as the ideal time of administration during the course of periodontal treatment. Although these agents are often prescribed after the healing phase of the SRP procedure, there is biological plausibility to support its use in conjunction with the mechanical treatment. However, to date, no placebo controlled randomized clinical trial (RCT) has directly compared these two protocols. Therefore, the aim of this RCT is to compare the clinical, microbiological and immunological effects of the adjunctive systemic MTZ + AMX administered in different phases of the treatment of severe periodontitis.

Methods

Subjects with severe periodontitis (n = 180) are being randomly assigned into three groups (n = 60/group): (i) SRP-only (control group), SRP in combination with 400 mg MTZ + 500 mg AMX, starting (ii) at the first SRP session (active phase group), or (iii) after 3 months of its completion (healing phase group). All volunteers are receiving clinical and microbiological evaluation at baseline, 3, 6 and 12 months, and immunological assessment at baseline and 12 months post-therapy. Nine subgingival biofilm samples are being collected per subject and analyzed for counts and proportions of 40 bacterial species by checkerboard DNA-DNA hybridization, and six gingival crevicular fluid samples are being collected and analyzed for the levels of 20 chemokines by multiplex immunoassay. The primary outcome variable is the number of volunteers reaching the clinical endpoint for treatment (≤ 4 sites with probing depth ≥5 mm) at 1 year post-therapy. Differences in clinical, microbiological and immunological parameters among groups and over time will be evaluated using analysis of variance, analysis of covariance and the Chi-square and Tukey tests. Microbiological and immunological analyses will be performed using adjustments for multiple comparisons. Statistical significance will be set at 5%.

Trial registration

ClinicalTrials.gov, NCT02954393. Registered on 3 November 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2540-8) contains supplementary material, which is available to authorized users.

The subgingival periodontal microbiota of the aging mouth

Different mechanisms have been hypothesized to explain the increase in prevalence and severity of periodontitis in older adults, including shifts in the periodontal microbiota. However, the actual impact of aging on the composition of subgingival biofilms remains unclear. In the present article, we provide an overview of the composition of the subgingival biofilm in older adults and the potential effects of age on the oral microbiome. In particular, this review covers the following topics: (i) the oral microbiota of an aging mouth; (ii) the effects of age and time on the human oral microbiome; (iii) the potential impact of inflammaging and immunosenescence in the host-oral microbiota interactions; and (iv) the relationship of the aging oral microbiota and Alzheimer's disease. Finally, we present analyses of data compiled from large clinical studies that evaluated the subgingival microbiota of periodontally healthy subjects and patients with periodontitis from a wide age spectrum (20-83 years of age).

Do different probing depths exhibit striking differences in microbial profiles?

AIM

To perform a thorough characterization of the subgingival microbiota of shallow, moderate and deep sites in subjects with chronic periodontitis (ChP).

MATERIAL AND METHODS

Subgingival samples were collected from subjects with ChP (n = 3/category of probing depth: ≤3, 4-6 and ≥7 mm) and periodontal health (PH). Individual samples were submitted to 16S rDNA high- throughput sequencing and the analysis was made using mothur and R packages.

RESULTS

Nine subjects with ChP and seven with PH were included and 101 samples were evaluated. Thirteen phyla, 118 genera and 211 OTUs were detected. Taxa from Chloroflexi and Spirochaetes phyla were associated with initial stages of disease. Fretibacterium, Eubacterium[XI][G-6], Desulfobulbus, Peptostreptococcaceae[XI][G-1] and [G-3], Bacteroidetes[G-3], Bacteroidaceae[G-1] genera and Filifactor alocis, Fretibacterium fastidiosum, Johnsonella spHOT166, Peptostreptococcaceae[XIII][G-1]HOT113, Porphyromonas endodontalis and Treponema sp. HOT258, which are not conventionally associated with disease, increased with the deepening of the pockets and/or were elevated in ChP; while Streptococcus, Corynebacterium and Bergeyella genera were associated with PH (p < .05).

CONCLUSION

Striking differences were observed between the microbiota of shallow and moderate/deep sites, but not between moderate and deep sites in ChP subjects. Differences between shallow sites in PH and ChP were also observed. The characterized microbiota included known oral microorganisms and newly identified periodontal taxa, some of them not-yet-cultured.

Effectiveness of a pre-procedural mouthwash in reducing bacteria in dental aerosols: randomized clinical trial

The aim of this randomized, single blinded clinical trial was to evaluate the effect of a pre-procedural mouthwash containing cetylpyridinium chloride (CPC), zinc lactate (Zn) and sodium fluoride (F) in the reduction of viable bacteria in oral aerosol after a dental prophylaxis with ultrasonic scaler. Sixty systemically healthy volunteers receiving dental prophylaxis were randomly assigned to one of the following experimental groups (15 per group): (i) rinsing with 0.075% CPC, 0.28% Zn and 0.05% F (CPC+Zn+F), (ii) water or (iii) 0.12% chlorhexidine digluconate (CHX), and (iv) no rinsing. Viable bacteria were collected from different locations in the dental office on enriched TSA plates and anaerobically incubated for 72 hours. The colonies were counted and species were then identified by Checkerboard DNA-DNA Hybridization. The total number of colony-forming units (CFUs) detected in the aerosols from volunteers who rinsed with CPC+Zn+F or CHX was statistically significantly (p<0.05) lower than of those subjects who did not rinse or who rinsed with water. When all locations were considered together, the aerosols from the CPC+Zn+F and CHX groups showed, respectively, 70% and 77% fewer CFUs than those from the No Rinsing group and 61% and 70% than those from the Water group. The mean proportions of bacterial species from the orange complex were statistically significantly (p<0.05) lower in aerosols from the CPC+Zn+F and CHX groups compared with the others two groups. In conclusion, the mouthwash containing CPC+Zn+F, is effective in reducing viable bacteria in oral aerosol after a dental prophylaxis with ultrasonic scaler.

Systemic antibiotics in the treatment of periodontitis

Despite the fact that several clinical studies have shown additional benefits when certain systemic antibiotics are used as adjuncts to periodontal treatment, clear guidelines for the use of these agents in the clinical practice are not yet available. Basic questions concerning the use of systemic antibiotics to treat periodontitis remain unanswered, such as: which drug(s) should be used; which patients would most benefit from treatment; which are the most effective protocols (i.e. doses and durations); and in which phase of the mechanical therapy should the drug(s) be administered? Although not all of those questions have been directly addressed by controlled randomized clinical trials, recent concepts related to the ecology of periodontal diseases, as well as the major advances in laboratory and clinical research methods that have occurred in the past decade, have significantly broadened our knowledge in this field. This article endeavored to provide a 'state of the art' overview on the use of systemic antibiotics in the treatment of periodontitis, based on the most recent literature on the topic as well as on a compilation of data from studies conducted at the Center of Clinical Trials at Guarulhos University (São Paulo, Brazil) from 2002 to 2012.

Association of three putative periodontal pathogens with chronic periodontitis in Brazilian subjects

Objective

The aim of this study was to evaluate the association of Porphyromonas endodontalis, Filifactor alocis and Dialister pneumosintes with the occurrence of periodontitis.

Material and Methods

Thirty subjects with chronic periodontitis (ChP) and 10 with periodontal health (PH) were included in the study. Nine subgingival biofilm samples were collected as follows: i) PH group - from the mesial/buccal aspect of each tooth in two randomly chosen contralateral quadrants; ii) ChP group - from three sites in each of the following probing depth (PD) categories: shallow (≤3 mm), moderate (4-6 mm) and deep (≥7 mm). Checkerboard DNA-DNA hybridization was used to analyze the samples.

Results

We found the three species evaluated in a higher percentage of sites and at higher levels in the group with ChP than in the PH group (p<0.05, Mann-Whitney test). We also observed these differences when the samples from sites with PD≤4 mm or ≥5 mm of subjects with ChP were compared with those from subjects with PH (p<0.05, Mann-Whitney test). In addition, the prevalence and levels of D. pneumosintes, and especially of F. alocis were very low in healthy subjects (0.12x10⁵ and 0.01x10⁵, respectively).

Conclusion

F. alocis and D. pneumosintes might be associated with the etiology of ChP, and their role in the onset and progression of this infection should be further investigated. The role of P. endodontalis was less evident, since this species was found in relatively high levels and prevalence in the PH group.

Transforming growth factor-β, interleukin-17, and IL-23 gene expression profiles associated with human peri-implantitis

OBJECTIVES

The mRNA expression profiles of IL-23/Th17 and the Treg-associated cytokine TGF-β in peri-implantitis are currently under research. This study characterized the IL-17, IL-23, and TGF-β gene expression levels in healthy and diseased peri-implant tissues and correlated these data with radiographic bone loss.

MATERIAL AND METHODS

Peri-implant soft tissues from 40 subjects (20 healthy controls with mean age of 59.4 ± 6.3, and 20 with peri-implantitis with mean age of 56.6 ± 5.5) were enrolled in this study, and real-time PCR (RT-PCR) was used to define the profile of IL-17, IL-23, and TGF-β gene expression.

RESULTS

Higher levels of TGF-β mRNA were observed in biopsies taken from healthy controls, and the IL-23 mRNA levels were significantly increased in the peri-implantitis group (P < 0.0001). No differences in IL-17 mRNA levels were observed between the two groups (P > 0.05).

CONCLUSIONS

Data presented in this report demonstrated a predominant Th17 response in peri-implantitis subjects based on the higher levels of IL-23 and lower levels of TGF-β detected.

Amoxicillin Plus Metronidazole Therapy for Patients with Periodontitis and Type 2 Diabetes

The aim of this study was to assess the changes occurring in subgingival biofilm composition and in the periodontal clinical parameters of subjects with periodontitis and type 2 diabetes mellitus (DM) treated by means of scaling and root planing (SRP) only or combined with systemic metronidazole (MTZ) and amoxicillin (AMX). Fifty-eight subjects were randomly assigned to receive SRP only ( n = 29) or with MTZ (400 mg/thrice a day [TID]) and AMX (500 mg/TID) ( n = 29) for 14 d. Six subgingival plaque samples/subject were analyzed by checkerboard DNA–DNA hybridization for 40 bacterial species at baseline and 3 mo, 1 y, and 2 y posttherapy. At 2 y posttherapy, the antibiotic-treated group harbored lower mean proportions (5.5%) of red complex pathogens than the control group (12.1%) ( P < 0.05). The proportions of the Actinomyces species remained stable in the antibiotic group but showed a statistically significant reduction in the control group from 1 to 2 y in subjects achieving a low risk clinical profile for future disease progression (i.e., ≤4 sites with probing depth [PD] ≥5 mm). The test group also had a lower mean number of sites with PD ≥5 mm (3.5 ± 3.4) and a higher percentage of subjects reaching the low risk clinical profile (76%) than the control group (14.7 ± 13.1 and 22%, respectively) ( P < 0.05) at 2 y posttreatment. MTZ + AMX intake was the only significant predictor of subjects achieving the low risk at 2 y (odds ratio, 20.9; P = 0.0000). In conclusion, the results of this study showed that the adjunctive use of MTZ + AMX improves the microbiological and clinical outcomes of SRP in the treatment of subjects with generalized chronic periodontitis and type 2 DM up to 2 y ( ClinicalTrials.gov NCT02135952).

Levels of Candidate Periodontal Pathogens in Subgingival Biofilm

In recent years, several new periodontal taxa have been associated with the etiology of periodontitis. A recent systematic review provides further support for the pathogenic role of 17 species/phylotypes. Thus, the aim of this study was to assess the prevalence and levels of these species in subjects with generalized chronic periodontitis (GChP; n = 30), generalized aggressive periodontitis (GAgP; n = 30), and periodontal health (PH; n = 30). All subjects underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analyzed for their content of 20 bacterial species/phylotypes through the RNA-oligonucleotide quantification technique. Subjects from the GChP and GAgP groups presented the highest mean values for all clinical parameters in comparison with the PH group (P < 0.05). Subjects with GChP and GAgP showed significantly higher mean levels of Bacteroidetes sp. human oral taxon (HOT) 274, Fretibacterium sp. HOT 360, and TM7 sp. HOT 356 phylotypes, as well as higher mean levels of Filifactor alocis, Fretibacterium fastidiosum, Porphyromonas gingivalis, Tannerella forsythia, and Selenomonas sputigena species than PH subjects (P < 0.05). GAgP subjects presented higher mean levels of TM7 sp. HOT 356 and F. alocis than GChP subjects (P < 0.05). A significantly higher mean prevalence of Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, and Fretibacterium sp. HOT 362 was found in subjects with GChP and GAgP than in PH subjects. Mean levels of P. gingivalis (r = 0.68), T. forsythia (r = 0.62), F. alocis (r = 0.51, P = 0.001), and Fretibacterium sp. HOT 360 (r = 0.41) were correlated with pocket depth (P < 0.001). In conclusion, Bacteroidales sp. HOT 274, Desulfobulbus sp. HOT 041, Fretibacterium sp. HOT 360, Fretibacterium sp. HOT 362, and TM7 sp. HOT 356 phylotypes, in addition to F. alocis, F. fastidiosum, and S. sputigena, seem to be associated with periodontitis, and their role in periodontal pathogenesis should be further investigated.

The effect of systemic antibiotics administered during the active phase of non-surgical periodontal therapy or after the healing phase: a systematic review

Objective

The aim of this systematic review was to compare the clinical effectiveness of systemic antibiotics administered in the active stage of periodontal treatment or after the healing phase.

Material and Methods

An electronic search was performed in the databases EMBASE, MEDLINE and Cochrane Central Register of Controlled Trials (CENTRAL), in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement. A manual search of the reference list of selected studies and of review articles was also performed up to November 2013. Randomized Clinical Trials (RCT) that evaluated the systemic administration of antibiotics as adjuvants to scaling and root planning (SRP) at different phases of periodontal treatment were included. Systematic reviews and studies that evaluated subjects with systemic diseases and those that used subantimicrobial doses of antibiotics were excluded.

Results

The initial search identified 1,039 articles, of which seven were selected, and only one met the inclusion criteria. This study showed that subjects taking metronidazole and amoxicillin at the initial phase of treatment exhibited statistically significantly greater reduction in pocket depth and gain in clinical attachment level in initially deep sites (PD≥7 mm) than subjects taking antibiotics after healing (p<0.05). This comparison was conducted 2 months after antibiotic intake, at the healing phase.

Conclusion

To date, only one short-term RCT has directly compared different moments of systemic antibiotics administration, as adjuncts to SRP, in the treatment of periodontitis. Although the results of this study suggested some benefits for antibiotics intake during the active phase of therapy, these findings need to be confirmed by larger placebo-controlled randomized clinical trials with longer follow-up periods.

The efficacy of two oral hygiene regimens in reducing oral malodour: a randomised clinical trial

OBJECTIVES

This study compared the efficacy of two oral hygiene regimens in reducing oral malodour and the proportions of bacterial species involved in the production of volatile sulphur compounds.

MATERIAL AND METHODS

Seventy subjects who participated in a halitosis-induction phase and achieved an organoleptic score of ≥ 3.0 [time point 0 (T0)] randomised into two groups: brushing with regular fluoride toothpaste alone (control group) or brushing with regular fluoride toothpaste followed by rinsing with a 0.075% cetylpyridinium chloride (CPC) mouthwash (CPC group). Subjects followed their assigned oral hygiene regimen for 21 days. Then, they underwent an organoleptic examination and measurement of volatile sulphur compounds (VSCs) using a portable gas chromatograph, 12 hours after their last oral hygiene procedure (T1) and 4 hours after an on-site oral hygiene (T2). Microbiological samples (supragingival biofilm, tongue coating and saliva) were analysed using checkerboard DNA-DNA hybridisation.

RESULTS

Both therapies statistically significantly improved the organoleptic scores (P < 0.05), but the VSC levels and/or concentrations were reduced only in the CPC group (P < 0.05). In subjects rinsing with CPC, oral malodour scores were reduced by 49% at the 4-hour assessment (T2) compared with those not rinsing (P < 0.05). Red-complex pathogens were reduced more effectively in the CPC group than in the control group.

CONCLUSIONS

Brushing followed by rinsing with a 0.075% CPC mouthwash provided statistically significantly greater reductions in oral malodour, measured organoleptically and instrumentally, and in the proportions of red-complex species when compared with brushing alone.

Subgingival bacterial recolonization after scaling and root planing in smokers with chronic periodontitis

BACKGROUND

The aim of this study was to compare subgingival bacterial recolonization patterns after scaling and root planing in current smokers and non-smokers.

METHODS

15 smokers and 15 non-smokers with chronic periodontitis received scaling and root planing in six visits lasting one hour each, over a period of 21 days. Clinical monitoring was performed at baseline and 180 days, and microbiological monitoring was performed at baseline, immediately after scaling and root planing (Day 0) and at 42, 63 and 180 days post-therapy. Subgingival plaque samples were analysed by checkerboard DNA-DNA hybridization.

RESULTS

An improvement in clinical condition was observed for smokers and non-smokers; however, non-smokers showed a greater reduction in mean clinical attachment level in intermediate sites in comparison with smokers (p < 0.05). At Day 0, there was a significant reduction in the mean counts of the three pathogens from the red complex, Eubacterium nodatum and Parvimonas micra only in non-smokers (p < 0.05). There was a significant increase in the proportion of host-compatible species in non-smokers and smokers from baseline to 180 days post-therapy (p < 0.05). However, a significant decrease in the pathogenic species was observed only in non-smokers.

CONCLUSIONS

Smokers were more susceptible to the re-establishment of a pathogenic subgingival biofilm than non-smokers.

Microbiological diversity of peri-implantitis biofilms

The open-ended microbial diagnostic approaches such as the complete or partial sequencing of the 16S ribosomal gene by Sanger sequencing or by pyrosequencing have provided new insights into the diversity of the oral microbiota. These techniques have recently been used to evaluate the microbiota associated with osseointegrated implants and these results have expanded the knowledge on the diversity of the microbial communities associated with peri-implantitis. Taken together, the results of these studies suggest that the diversity of the microbial community of peri-implantitis and periodontitis might not be as similar as previously thought. Although certain known periodontal pathogens may also be associated with the etiology of peri-implantitis, apparently there were many differences between these two clinical conditions, involving distinct microorganisms. Further investigations on the diversity of peri-implant microbiota would be essential in order to define effective preventive and therapeutic strategies for peri-implantitis. It is also important to standardize laboratory protocols to make the results of the open-ended diagnostic techniques based on PCR amplification more comparable throughout the different research groups.