Long-term changes in the subgingival microbiota in patients with stage III-IV periodontitis treated by mechanical therapy and adjunctive systemic antibiotics: A secondary analysis of a randomized controlled trial.

AIM: To explore whether adjunctive antibiotics can relevantly influence long-term microbiota changes in stage III-IV periodontitis patients. MATERIALS AND METHODS: This is a secondary analysis of a randomized clinical trial on periodontal therapy with adjunctive 500 mg amoxicillin and 400 mg metronidazole or placebo thrice daily for 7 days. Subgingival plaque samples were taken before and 2, 8, 14 and 26 months after mechanical therapy. The V4-hypervariable region of the 16S rRNA gene was sequenced with Illumina MiSeq 250 base pair paired-end reads. Changes at the ribosomal sequence variant (RSV) level, diversity and subgingival-microbial dysbiosis index (SMDI) were explored with a negative binomial regression model and non-parametric tests. RESULTS: Overall, 50.2% of all raw reads summed up to 72 RSVs (3.0%) that were generated from 163 stage III-IV periodontitis patients. Of those, 16 RSVs, including Porphyromonas gingivalis, Tannerella forsythia and Aggregatibacter actinomycetemcomitans, changed significantly over 26 months because of adjunctive systemic antibiotics. SMDI decreased significantly more in the antibiotic group at all timepoints, whereas the 2-month differences in alpha and beta diversity between groups were not significant at 8 and 14 months, respectively. CONCLUSIONS: Mechanical periodontal therapy with adjunctive antibiotics induced a relevant and long-term sustainable change towards an oral microbiome more associated with oral health.

Clinical benefits of systemic amoxicillin/metronidazole may depend on periodontitis stage and grade: An exploratory sub-analysis of the ABPARO trial.

AIM: Assessment of treatment response after systemic amoxicillin/metronidazole adjunctive to subgingival instrumentation (SI) according to stages and grades of the 2018 classification of periodontal diseases. MATERIALS AND METHODS: We carried out exploratory re-analysis of the placebo-controlled, multi-centre ABPARO trial (52; 45/60 years of age; 205 males, 114 active smokers). Patients were randomized to SI with systemic amoxicillin 500 mg/metronidazole 400 mg (three times a day for 7 days, n = 205; ANTI) or placebo (n = 200; PLAC) and maintenance therapy every 3 months. Patients were reclassified according to the 2018 classification (stage/extent/grade). Treatment effect was the percentage of sites per patient with new attachment loss ≥1.3 mm (PSAL ≥ 1.3 mm) at 27.5 months post-baseline/randomization. RESULTS: All patients were assigned according to the stage (n = 49 localized stage III, n = 206 generalized stage III, n = 150 stage IV). Because of missing radiographs, only 222 patients were assigned to grades (n = 73 B, n = 149 C). Treatment (PLAC/ANTI) resulted in PSAL ≥ 1.3 mm (median; lower/upper quartile) in localized stage III (PLAC: 5.7; 3.3/8.4% vs. ANTI: 4.9; 3.0/8.3%; p = .749), generalized stage III (8.0; 4.5/14.3% vs. 4.7; 2.4/9.0%; p < .001), stage IV (8.5; 5.1/14.4% vs. 5.7; 3.3/10.6%; p = .008), grade B (4.4; 2.4/6.7% vs. 3.6; 1.9/4.7%; p = .151) and grade C (9.4; 5.3/14.3% vs. 4.8; 2.5/9.4%; p < .001). CONCLUSIONS: In generalized periodontitis stage III/grade C, a clinically relevant lower percentage of disease progression after adjunctive systemic amoxicillin/metronidazole was observed compared to placebo (PLAC: 9.7; 5.8/14.3% vs. ANTI: 4.7; 2.4/9.0%; p < .001).

The Role of Polymorphisms at the Interleukin-1, Interleukin-4, GATA-3 and Cyclooxygenase-2 Genes in Non-Surgical Periodontal Therapy.

Periodontitis is a multifactorial disease. The aim of this explorative study was to investigate the role of Interleukin-(IL)-1, IL-4, GATA-3 and Cyclooxygenase-(COX)-2 polymorphisms after non-surgical periodontal therapy with adjunctive systemic antibiotics (amoxicillin/metronidazole) and subsequent maintenance in a Caucasian population. Analyses were performed using blood samples from periodontitis patients of a multi-center trial (ClinicalTrials.gov NCT00707369=ABPARO-study). Polymorphisms were analyzed using quantitative real-time PCR. Clinical attachment levels (CAL), percentage of sites showing further attachment loss (PSAL) ≥1.3 mm, bleeding on probing (BOP) and plaque score were assessed. Exploratory statistical analysis was performed. A total of 209 samples were genotyped. Patients carrying heterozygous genotypes and single-nucleotide-polymorphisms (SNP) on the GATA-3-IVS4 +1468 gene locus showed less CAL loss than patients carrying wild type. Heterozygous genotypes and SNPs on the IL-1A-889, IL-1B +3954, IL-4-34, IL-4-590, GATA-3-IVS4 +1468 and COX-2-1195 gene loci did not influence CAL. In multivariate analysis, CAL was lower in patients carrying GATA-3 heterozygous genotypes and SNPs than those carrying wild-types. For the first time, effects of different genotypes were analyzed in periodontitis progression after periodontal therapy and during supportive treatment using systemic antibiotics demonstrating a slight association of GATA-3 gene locus with CAL. This result suggests that GATA-3 genotypes are a contributory but non-essential risk factor for periodontal disease progression.

Effect of periodontal therapy on adipokine biomarkers in overweight.

AIM: The aim of this study was to evaluate the effect of non-surgical periodontal therapy on circulating levels of the systemic inflammation-associated biomarkers orosomucoid (ORM), high-sensitivity C-reactive protein (hsCRP), chemerin, and retinol-binding protein 4 (RBP4) in overweight or normal-weight patients with periodontitis at 27.5 months after therapy. MATERIALS AND METHODS: This exploratory subanalysis includes patients from the ABPARO-trial (ClinicalTrials.gov NCT00707369). The per-protocol collective provided untreated periodontitis patients with high (≥28 kg/m2 ) or moderate (21-24 kg/m2 ) BMI. Out of the per-protocol collective, 80 patients were randomly selected and stratified for BMI group, sex, and treatment group (antibiotics/placebo), resulting in 40 overweight and normal-weight patients. Patients received non-surgical periodontal therapy and maintenance at 3-month intervals. Plasma samples from baseline and 27.5 months following initial treatment were used to measure the concentrations of ORM, hsCRP, chemerin, and RBP4. RESULTS: At the 27.5-month examination, ORM and hsCRP decreased noticeably in the overweight group (ORM: p = .001, hsCRP: p = .004) and normal-weight patients (ORM: p = .007, hsCRP: p < .001). Chemerin decreased in the overweight group (p = .048), and RBP4 concentrations remained stable. CONCLUSION: Non-surgical periodontal therapy reduced systemically elevated inflammation-associated biomarkers in periodontitis patients. These improvements were more pronounced in overweight patients than in normal-weight patients.

A genome-wide association study identifies nucleotide variants at SIGLEC5 and DEFA1A3 as risk loci for periodontitis.

Periodontitis is one of the most common inflammatory diseases, with a prevalence of 11% worldwide for the severe forms and an estimated heritability of 50%. The disease is characterized by destruction of the alveolar bone due to an aberrant host inflammatory response to a dysbiotic oral microbiome. Previous genome-wide association studies (GWAS) have reported several suggestive susceptibility loci. Here, we conducted a GWAS using a German and Dutch case-control sample of aggressive periodontitis (AgP, 896 cases, 7,104 controls), a rare but highly severe and early-onset form of periodontitis, validated the associations in a German sample of severe forms of the more moderate phenotype chronic periodontitis (CP) (993 cases, 1,419 controls). Positive findings were replicated in a Turkish sample of AgP (223 cases, 564 controls). A locus at SIGLEC5 (sialic acid binding Ig-like lectin 5) and a chromosomal region downstream of the DEFA1A3 locus (defensin alpha 1-3) showed association with both disease phenotypes and were associated with periodontitis at a genome-wide significance level in the pooled samples, with P = 1.09E-08 (rs4284742,-G; OR = 1.34, 95% CI = 1.21-1.48) and P = 5.48E-10 (rs2738058,-T; OR = 1.28, 95% CI = 1.18-1.38), respectively. SIGLEC5 is expressed in various myeloid immune cells and classified as an inhibitory receptor with the potential to mediate tyrosine phosphatases SHP-1/-2 dependent signaling. Alpha defensins are antimicrobial peptides with expression in neutrophils and mucosal surfaces and a role in phagocyte-mediated host defense. This study identifies the first shared genetic risk loci of AgP and CP with genome-wide significance and highlights the role of innate and adaptive immunity in the etiology of periodontitis.

Finding an upper limit of what might be achievable by patients: oral cleanliness in dental professionals after self-performed manual oral hygiene.

AIMS: Though patients have been shown to have difficulties in achieving oral cleanliness after self-performed oral hygiene, scientifically and empirically justified standards for the degree of oral cleanliness they should achieve are lacking. Oral cleanliness of dental staff was therefore assessed as an indicator of what might be an upper limit of what can be expected by patients. MATERIALS AND METHODS: In a multicentre study, N = 64 university dentists, N = 33 dental students and N = 30 dental assistants were asked to perform manual oral hygiene to the best of their abilities. The presence or absence of dental plaque adjacent to gingival margins was assessed by the marginal plaque index (MPI). As full-crown index, the Turesky modification of the Quigley and Hein Index (QHIm) was applied. RESULTS: Only three participants showed papillary bleeding and only one a clinical pocket depth of more than 3.5 mm. After self-performed oral hygiene, no differences between groups were observed with respect to plaque nor did results differ between those who habitually used a powered toothbrush only and those who did not. Most participants (96%) achieved oral cleanliness at more than 70% of their gingival margins and QHIm levels below .63. Half of the participants showed QHIm levels below .17 and oral cleanliness at 96% of gingival margins. CONCLUSIONS AND CLINICAL RELEVANCE: Considering that half of the dental professionals achieved oral cleanliness at 96% of gingival margins and QHIm levels below .17 after thorough oral hygiene, this might reflect an upper limit of what can be expected by patients.

A haplotype block downstream of plasminogen is associated with chronic and aggressive periodontitis.

AIM: The intronic variant rs4252120 in the plasminogen gene (PLG) is known to be associated with aggressive periodontitis (AgP) and atherosclerosis. Here, we examined the chromosomal region spanning PLG for associations with both chronic periodontitis (CP) and AgP. MATERIALS AND METHODS: The association of PLG candidate rs4252120 was tested in a German case-control sample of 1,419 CP cases using the genotyping assay hCV11225947 and 4,562 controls, genotyped with HumanOmni BeadChips. The German and Dutch sample of AgP cases (N = 851) and controls (N = 6,836) were genotyped with HumanOmni BeadChips. The North American CP sample (N = 2,681 cases, 1,823 controls) was previously genotyped on the Genome-Wide Human SNP Array 6.0. Genotypes were imputed (software Impute v2), and association tests were performed using an additive genetic model adjusting for sex and smoking. RESULTS: Rs4252120 was not associated with CP. However, a haplotype block downstream of PLG and not in linkage disequilibrium with rs4252120 (r2  = .08) was associated with both AgP (rs1247559; p = .002, odds ratio [OR] = 1.33) and CP (p = .02, OR = 1.15). That locus was also significantly associated with PLG expression in osteoblasts (p = 6.9 × 10-5 ). CONCLUSIONS: Our findings support a role of genetic variants in PLG in the aetiology of periodontitis.

Is furcation involvement affected by adjunctive systemic amoxicillin plus metronidazole? A clinical trials exploratory subanalysis.

OBJECTIVES: Evaluation of the clinical effect of systemic amoxicillin and metronidazole adjunctively to mechanical debridement at furcation sites. MATERIAL AND METHODS: This is an exploratory per-protocol collective subanalysis from a prospective, randomized, double-blind, multi-centre trial (ClinicalTrials.gov NCT00707369) on the effect of adjunctive systemic amoxicillin 500 mg plus metronidazole 400 mg (3×/day, 7 days) use on furcation involvement in moderate to severe periodontitis. Outcome was the change in frequency of classes of furcation involvement after 27.5 months. Therapy comprised mechanical debridement in conjunction with antibiotic or placebo administration, and maintenance therapy at three months intervals. RESULTS: Three hundred and forty-five patients (175 placebo, 170 antibiotics) with 6576 furcation sites (class 0 2956; class I 2370; class II 886; class III 364) were examined (3472 placebo, 3104 antibiotics). Pocket reduction/attachment gain at the furcation sites was noticeably better after antibiotics (1.2/0.6 mm) than after placebo (0.7/0.2 mm) 27.5 months after therapy. However, most furcation degrees were unchanged (placebo 61.5%/antibiotics 62.2%), more sites improved than deteriorated (20.3%/18.2%, 22.1%/15.7% respectively) and no differences in the change of furcation degrees between treatments could be detected. CONCLUSION: Compared to placebo, prescription of adjunctive systemic antibiotics failed to show clinically relevant benefit with regard to furcation class involvement.

Three-year results following regenerative periodontal surgery of advanced intrabony defects with enamel matrix derivative alone or combined with a synthetic bone graft.

OBJECTIVES: This study aims to compare the clinical outcomes of a combination of enamel matrix derivatives (EMD) and a synthetic bone graft (biphasic calcium phosphate) with EMD alone in wide and deep one- and two-wall intrabony defects 36 months after treatment. MATERIAL AND METHODS: Thirty patients with chronic periodontitis and one wide (≥ 2 mm) and deep (≥ 4 mm) intrabony defect had been recruited in three centres in Germany. During surgery, defects were randomly assigned to EMD/synthetic bone graft (SBG) (test) or EMD (control). Assessments at baseline, after 6, 12 and 36 months, included bone sounding, relative clinical attachment levels, probing pocket depths and recessions. RESULTS: After 36 months, defects in both groups were significantly improved (p < 0.001) with regard to defect fill, attachment gain and probing pocket reduction. In the EMD/SBG group, a mean defect fill of 2.6 mm (±1.7) was measured, and in the EMD group, the defect fill was 2.3 mm (±1.5). A mean gain in clinical attachment of 4.1 mm (±3.6) and 3.8 mm (±2.2) was observed in the test and in the control group, respectively. There were no statistically significant differences in any of the investigated parameters between the two treatment modalities. CONCLUSIONS: The clinical improvements of advanced intrabony defects obtained with both regenerative modalities could be maintained over a period of 3 years. The combination of EMD with SBG did not show any advantage compared to the use of EMD alone.

Neutrophil activation and periodontal tissue injury.

Neutrophilic polymorphonuclear leukocytes (PMNL) track, engage and eliminate foreign entities, including bacteria, fungi and subcellular particles. PMNL are the major host-cell line involved in the acute response during the early stages of infections, including those in the oral cavity. Rather short lived, they are among the fastest moving cells in the human body and travel great distances only to be immolated after encountering and neutralizing antigens. Although their role as the first line of host defense is well established, their role in chronic granulomatous inflammations, diseases and infections remains poorly understood, and many questions on the activation, motility, bactericidity and termination of PMNL in these conditions remain unanswered. This review aims to summarize our current understanding of the molecular mechanisms of PMNL activation and signaling events. Recent evidence indicates the presence of collateral tissue damage caused by poorly regulated PMNL pursuits of periodontal bacteria. Imbalances between the antigenic challenge and the primary host response may augment periodontal tissue breakdown. Thereafter, orchestrated regulation of the resolution of inflammation fails in the presence of a pathogenic periodontal biofilm.

Inflammatory reaction - communication of cells.

This article presents scientific background information on the animated 3D film "Inflammatory Reactions - Communication of Cells" (Quintessence Publications, ISBN 978-1-85097-231-0). Gingivitis and periodontitis are understood as the result of a coordinated action of a few clearly identified cellular players who communicate with each other via cytokines. For didactic reasons, the course of a periodontal infection is described here in four phases: (1) bacterial biofilm formation and development of a host response in the marginal periodontium, (2) innate immune response leading to gingivitis, (3) role of the adaptive immune system in attachment loss and pocket formation, and (4) down-regulation of inflammation and periodontal regeneration and repair following biofilm removal. The control of the cells is discussed as a cytokine network, which can be modulated in pro- or anti-inflammatory direction depending on the control of the bacterial infection. Degradation of soft tissue structural proteins like collagen and proteoglycans by matrix metalloproteinases and degradation of hard tissue matrix by osteoclasts are explained as an interference of the immune system with the natural equilibrium of tissue remodeling. Five mechanisms of promotion of bone loss through the influence of the immune system are described. One example is bone resorption as a consequence of the shift of the RANKL/osteoprotegerin balance by soluble RANKL synthesized by CD4(+) Th 1 cells as well as the interference with the coupling of osteoclasts and osteoblasts through dedifferentiation of osteoblasts by TNFα. Finally, the signaling required for down-regulation of inflammatory reactions and the reasons for the incomplete regeneration after periodontal bone loss are discussed.

T helper cells from aggressive periodontitis patients produce higher levels of interleukin-1 beta and interleukin-6 in interaction with Porphyromonas gingivalis.

OBJECTIVE: In this study, we analyzed the production of Interleukin-1 beta (IL-1ß) and IL-6 by activated CD4+ cells obtained from aggressive periodontitis (AgP) patients in comparison with healthy subjects (HC). MATERIALS AND METHODS: CD4+ cells were automatically separated from lymphocytes obtained from peripheral blood of patients with AgP and healthy controls. Cells were activated for 4, 8, and 24 h with three different stimuli: anti-CD3/anti-CD28, phytohemagglutinin (PHA), and Porphyromonas gingivalis (P. gingivalis) outer membrane protein (OMP). Protein levels were measured in supernatants of activated CD4+ cells by a bead-based immunoassay (CBA). In addition, serum antibodies against P. gingivalis were determined. Data were analyzed using U test (p < 0.05). RESULTS: T helper cells of AgP patients activated with P. gingivalis OMP produced higher levels of IL-1ß and IL-6 in comparison with healthy controls (p < 0.05). Neither the activation with anti-CD3/anti-CD28 nor the activation with PHA showed significantly different production of IL-1ß and IL-6 by the cells 25 % of patients and 17 % of controls presented with high serum reactivity to P. gingivalis. CONCLUSION: In view of these results, it is possible to conclude that P. gingivalis contributes to the pathogenesis of AgP by inducing high levels of pro-inflammatory cytokines such as IL-1ß and IL-6 by peripheral CD4+ T helper cells. CLINICAL RELEVANCE: In accordance with the clinical parameters and the immunological data, we suggest that full-mouth disinfection with adjunctive systemic antibiotics might be the anti-infectious non-surgical periodontal treatment of choice in this type of patients. Microbiological analyses at the beginning and at the end of the periodontal treatment are recommended. However, it is necessary to verify these data in longitudinal clinical studies.

Expression and secretion levels of Th1 and Th2 cytokines in patients with aggressive periodontitis.

The role of Th1 and Th2 cytokines in the pathogenesis of aggressive periodontitis has not been previously examined. The aim of this study was to analyse the expression and production of IL-2, IFN-γ, IL-4 and IL-13 in CD4+ cells from the peripheral blood of patients with aggressive periodontitis (AgP) and periodontally healthy controls. Gene expression was analysed in inactivated and activated CD4+ cells by real-time PCR. Cells were activated for 4, 8 and 24 h with anti-CD3/CD28 antibody, phytohemagglutinin (PHA), and Porphyromonas gingivalis (P.g.) outer membrane protein (OMP). Protein levels were measured in supernatants of activated CD4+ cells by bead-based immunoassay (CBA). Statistics were performed using U test (p < 0.05). In controls, IL-4 expression was increased in inactivated CD4+ cells (p = 0.05), and IFN-γ and IL-2 expressions were increased in activated CD4+ cells: IFN-γ with anti-CD3/anti-CD28, P.g. OMP and PHA (p < 0.05); IL-2 with P.g. OMP and PHA (p < 0.05). In patients, although IL-4 and IL-13 expressions were higher in activated CD4+ cells, there were no differences compared to controls. The production of IL-4 and IL-2 was higher in the patients' CD4+ cells activated with PHA (p < 0.05). Although the results showed a predominantly Th1 mRNA profile in activated CD4+ cells of controls, protein concentrations showed no clear Th1 or Th2 profiles. The functional pathways of the Th cell immune response in aggressive periodontitis are still not well understood in order to develop individualised diagnostic and treatment plans.

Inflammatory effects of individualized abutments bonded onto titanium base on peri-implant tissue health: A randomized controlled clinical trial.

BACKGROUND: In implant prosthodontics, computer-assisted design and computer-assisted manufacturing (CAD/CAM) zirconia abutments bonded onto titanium bases are frequently used in prosthetic dentistry. Unpolymerized monomer of the bonding material or the adhesive gap itself may have a negative effect on peri-implant tissue health. However, evidence addressing this problem is not available. PURPOSE: The aim of the current trial was to study inflammatory effects of individualized abutments bonded onto titanium bases. MATERIAL AND METHOD: A total of 24 patients with one test abutment and one control abutment each participated in this prospective, double-blind, randomized controlled clinical trial. Thereby, test abutments were CAD/CAM titanium abutments bonded onto titanium abutments (Ti-Base). As control abutments individualized, one-piece CAD/CAM titanium abutments were used. At abutment installation as well as 6 and 12 months thereafter bone level changes, clinical parameters as well as Il-1ß levels were assessed. RESULTS: Neither for bone level or clinical parameters nor for Il-1ß levels, significant differences between test and control abutments could be found. However, in both groups Il-1ß levels were significantly elevated at both the 6 and 12 months follow-up compared to baseline. CONCLUSION: Within the limits of this RCT, it can be concluded that effects on the inflammatory state of peri-implant tissues do not differ between individualized abutments bonded onto Ti-Bases and individualized one-piece abutments.

Effects of Porphyromonas gingivalis infection on human gingival epithelial barrier function in vitro.

The gingival epithelium plays an important role in the protection of oral tissues from microbial challenge. Oral keratinocytes form various cellular contacts, including tight junctions, and thus are able to create an epithelial barrier. A measurable indicator of barrier function in vitro is the transepithelial electrical resistance (TER). Porphyromonas gingivalis is recognized as a major aetiologic agent of periodontal disease and exhibits a variety of virulence factors. The aim of the study was to investigate the effect, in vitro, of infection with P. gingivalis on gingival barriers composed of primary and immortalized human keratinocytes. Primary and immortalized human gingival keratinocytes were infected with different strains of P. gingivalis. The impact of the bacterial challenge on the barrier was analysed by measuring the TER. The destructive effects of gingipains were blocked by specific enzyme inhibitors. After an initial increase of about 20-30% in infected wells, the TER decreased to zero. Gingipain inhibitors delayed the destruction of the barrier by 12 ± 4 h. In all cases, the loss of TER was accelerated if the system was infected from the basolateral side. A distinct effect of P. gingivalis on the epithelial barrier function of three-dimensional cultured epithelial cell models was demonstrated, which can partly be attributed to the activity of gingipains.

Significant Short-Term Shifts in the Microbiomes of Smokers With Periodontitis After Periodontal Therapy With Amoxicillin & Metronidazole as Revealed by 16S rDNA Amplicon Next Generation Sequencing.

The aim of this follow-up study was, to compare the effects of mechanical periodontal therapy with or without adjunctive amoxicillin and metronidazole on the subgingival microbiome of smokers with periodontitis using 16S rDNA amplicon next generation sequencing. Fifty-four periodontitis patients that smoke received either non-surgical periodontal therapy with adjunctive amoxicillin and metronidazole (n = 27) or with placebos (n = 27). Subgingival plaque samples were taken before and two months after therapy. Bacterial genomic DNA was isolated and the V4 hypervariable region of the bacterial 16S rRNA genes was amplified. Up to 96 libraries were normalized and pooled for Illumina MiSeq paired-end sequencing with almost fully overlapping 250 base pairs reads. Exact ribosomal sequence variants (RSVs) were inferred with DADA2. Microbial diversity and changes on the genus and RSV level were analyzed with non-parametric tests and a negative binomial regression model, respectively. Before therapy, the demographic, clinical, and microbial parameters were not significantly different between the placebo and antibiotic groups. Two months after the therapy, clinical parameters improved and there was a significantly increased dissimilarity of microbiomes between the two groups. In the antibiotic group, there was a significant reduction of genera classified as Porphyromonas, Tannerella, and Treponema, and 22 other genera also decreased significantly, while Selenomonas, Capnocytophaga, Actinomycetes, and five other genera significantly increased. In the placebo group, however, there was not a significant decrease in periodontal pathogens after therapy and only five other genera decreased, while Veillonella and nine other genera increased. We conclude that in periodontitis patients who smoke, microbial shifts occurred two months after periodontal therapy with either antibiotics or placebo, but genera including periodontal pathogens decreased significantly only with adjunctive antibiotics.

Do we treat our patients or rather periodontal microbes with adjunctive antibiotics in periodontal therapy? A 16S rDNA microbial community analysis.

Empiric antibiotics are often used in combination with mechanical debridement to treat patients suffering from periodontitis and to eliminate disease-associated pathogens. Until now, only a few next generation sequencing 16S rDNA amplicon based publications with rather small sample sizes studied the effect of those interventions on the subgingival microbiome. Therefore, we studied subgingival samples of 89 patients with chronic periodontitis (solely non-smokers) before and two months after therapy. Forty-seven patients received mechanical periodontal therapy only, whereas 42 patients additionally received oral administered amoxicillin plus metronidazole (500 and 400 mg, respectively; 3x/day for 7 days). Samples were sequenced with Illumina MiSeq 300 base pairs paired end technology (V3 and V4 hypervariable regions of the 16S rDNA). Inter-group differences before and after therapy of clinical variables (percentage of sites with pocket depth ≥ 5mm, percentage of sites with bleeding on probing) and microbiome variables (diversity, richness, evenness, and dissimilarity) were calculated, a principal coordinate analysis (PCoA) was conducted, and differential abundance of agglomerated ribosomal sequence variants (aRSVs) classified on genus level was calculated using a negative binomial regression model. We found statistically noticeable decreased richness, and increased dissimilarity in the antibiotic, but not in the placebo group after therapy. The PCoA revealed a clear compositional separation of microbiomes after therapy in the antibiotic group, which could not be seen in the group receiving mechanical therapy only. This difference was even more pronounced on aRSV level. Here, adjunctive antibiotics were able to induce a microbiome shift by statistically noticeably reducing aRSVs belonging to genera containing disease-associated species, e.g., Porphyromonas, Tannerella, Treponema, and Aggregatibacter, and by noticeably increasing genera containing health-associated species. Mechanical therapy alone did not statistically noticeably affect any disease-associated taxa. Despite the difference in microbiome modulation both therapies improved the tested clinical parameters after two months. These results cast doubt on the relevance of the elimination and/or reduction of disease-associated taxa as a main goal of periodontal therapy.

A randomized clinical trial comparing enamel matrix derivative and membrane treatment of buccal class II furcation involvement in mandibular molars. Part II: secondary outcomes.

BACKGROUND: This multicenter, randomized trial compared enamel matrix derivative (EMD) with barrier membranes for the treatment of Class II mandibular furcations with regard to secondary outcomes. The influence of furcation morphology on the effectiveness of either treatment was also evaluated. METHODS: Forty-eight patients (age range 28 to 73 years; 22 females, 26 males) with buccal Class II furcation involvements in both contralateral lower first or second molars were included. After initial periodontal treatment, defects were randomized to either EMD or bioabsorbable guided tissue regeneration (GTR) barrier. Study design and the results for the primary parameter were previously described. Results of the following secondary outcome variables are reported here: changes of the hard tissue boundaries describing the anatomical situation of the furcation defect and changes in the following clinical parameters between baseline and 14 months: plaque, level of gingival margin, probing depth, bleeding on probing, attachment level, and bone sounding at five sites/tooth at the buccal side. Descriptive statistics were applied for changes in clinical parameters and measurements of hard tissue boundaries. The differences observed under treatment with EMD or membrane were analyzed by means of the Wilcoxon two-sample test. The difference between the effect of the EMD and membrane treatment was estimated by means of the Hodges-Lehmann estimator. RESULTS: Overall, similar healing results were observed for both treatments. However, there was slightly more recession in the mid-furcation site following membrane treatment (P = 0.04). Additionally, different treatment effects could be detected for the distances from the stent or cemento-enamel junction (CEJ) to the buccal bone crest, mid-distal root (Pstent = 0.01; PCEJ = 0.07) and for the distance from the stent or CEJ to the buccal bone crest, mid-mesial root (Pstent = 0.01; PCEJ = 0.01). There was no measurable bone resorption in EMD sites, whereas a slight resorption occurred with membrane treatment. Furcation morphology at the time of surgery was not associated with clinical outcome, irrespective of the treatment. CONCLUSION: With regard to secondary outcome parameters, enamel matrix derivative treatment led to a similar regenerative result as the membrane procedure.

A randomized clinical trial comparing enamel matrix derivative and membrane treatment of buccal Class II furcation involvement in mandibular molars. Part I: Study design and results for primary outcomes.

BACKGROUND: The objective of this multicenter, randomized trial was to compare enamel matrix derivative (EMD; test) with barrier membranes (control) for the treatment of mandibular buccal Class II furcation defects. METHODS: Forty-five patients with 90 comparable defects on contralateral molars were included. Defects were randomly assigned to EMD or bioabsorbable barrier membrane; the contralateral defect received the alternative treatment. Assessments at baseline and 8 and 14 months included gingival margin levels, probing depths, bleeding on probing, vertical attachment levels, and vertical bone sounding from a stent at five buccal sites/ tooth. Defect dimensions were recorded at surgery and during reentry at 14 months. Change of open horizontal furcation depth was the primary outcome variable. Adverse reactions and patient perceptions were also noted. RESULTS: Both treatment modalities led to significant clinical improvements. The median reduction of open horizontal furcation depth was 2.8 mm with the corresponding interquartile interval (1.5 mm, 3.5 mm) at test sites compared with 1.8 mm (1.0 mm, 2.8 mm) at control sites. The Hodges-Lehmann estimator of the advantage (reduction test versus control) was 0.75 mm (95% confidence interval [CI]: 0.125 mm, 1.375 mm, P = 0.033, Wilcoxon). The frequency of complete furcation closure was 8/45 (test) and 3/45 (control); partial closure, 27/45 in both groups; no change, 9/45 and 11/45, respectively; and deterioration, 1/45 and 4/45, respectively. The frequency of no pain or no swelling at 1 week post-surgery was 62% and 44%, respectively, at the test sites and 12% and 6% at the control sites. CONCLUSION: There was a significantly greater reduction in horizontal furcation depth and a comparatively lower incidence of postoperative pain/swelling following enamel matrix derivative compared to membrane therapy.