Antonis Konstantinidis

Prevalence and distribution of Aggregatibacter actinomycetemcomitans serotypes and the JP2 clone in a Greek population

AIM to investigate the distribution of Aggregatibacter actinomycetemcomitans serotypes and the prevalence of the JP2 clone in subgingival samples of Greek subjects. MATERIALS AND METHODS two hundred and twenty eight subjects participated in the present study. Each contributed with one pooled subgingival sample from the mesiobuccal surface of the four first molars. Samples were analysed using polymerase chain reaction for five serotypes of A. actinomycetemcomitans and the JP2 clone, using primers and conditions described previously. Subjects were stratified according to periodontal status (untreated periodontitis, non-periodontitis and periodontitis patients receiving supportive treatment). Comparisons between and within groups were performed by applying non-parametric tests (Kruskall-Wallis, Pearson χ(2) , z-test with Bonferronis corrections and Kramers V-test) at p=0.05 level. RESULTS a. actinomycetemcomitans was detected statistically more frequently in untreated patients (27.5%) compared with the other two groups (11.7% for non-periodontitis and 10% for periodontitis patients receiving supportive treatment). No statistical differences were observed concerning the distribution of serotypes among groups (z-test with Bonferronis corrections p>0.05). Serotype c was more predominant within the periodontally diseased groups (Kramers V-test p<0.05). The JP2 clone was not detected. CONCLUSIONS a. actinomycetemcomitans serotype b was not statistically correlated with periodontal disease in the investigated sample and the utility of microbiological testing before antimicrobial administration is emphasized.

Prevalence of tetM, tetQ, nim and blaTEM genes in the oral cavities of Greek subjects: a pilot study

AIM To investigate the prevalence of tetM, tetQ, nim and bla(TEM) antimicrobial resistance genes in subgingival and tongue samples of Greek subjects. MATERIALS AND METHODS Fifty-four subjects participated in the present study. Participants each contributed with one pooled subgingival sample from the mesiobuccal surface of the four first molars and one sample from the tongue. Samples were analysed using polymerase chain reaction for tetM, tetQ, nim and bla(TEM) genes using the primers and conditions described previously. Subjects were stratified according to periodontal status (health, gingivitis or periodontitis). Intake of any antibiotic for medical or dental reasons during the previous 12 months was also recorded (self-reported). Comparisons within and between groups were performed by applying non-parametric tests (z-test with Bonferroni corrections). RESULTS A high prevalence of tetM, tetQ and bla(TEM) genes was detected in both tongue and subgingival samples (48.1-82.2%). No differences were observed across genes between periodontally healthy, gingivitis or periodontitis cases, and no statistical correlation was observed between the presence of the bla(TEM) gene and the intake of beta-lactams during the last 12 months (Fishers exact test, p>0.05). CONCLUSIONS Findings from the present study suggest a high prevalence of tetM, tetQ and bla(TEM), but not nim resistance genes in subgingival and tongue samples from Greek subjects.

The influence of sex hormones on proinflammatory cytokines in gingiva of periodontally healthy premenopausal women

BACKGROUND AND OBJECTIVE The aim of this work was to investigate any correlation between the fluctuation of levels of specific proinflammatory cytokines in gingival crevicular fluid and the fluctuation of sex hormones in peripheral blood at ovulation and progesterone peak. MATERIAL AND METHODS Eighteen premenopausal women with normal and consistent menstrual cycles and healthy periodontium were included in this study. The exclusion criteria were as follows: (i) pregnancy; (ii) use of oral contraceptives; (iii) metabolic or systemic disease that might affect the periodontium; (iv) use of antimicrobial or nonsteroidal anti-inflammatory drugs during the past 6 mo; and (v) smoking. The measurements were performed at two specific time points for each participant [(i) on the day of ovulation; and (ii) on the day of the progesterone peak) and included the following: (i) plaque index; (ii) bleeding on probing; and (iii) the gingival crevicular fluid levels of interleukin (IL)-1β, IL-6, IL-8 and tumor necrosis factor-α (TNF-α). RESULTS During the menstrual cycle, plaque index values remained unchanged (0.71 ± 0.07 at ovulation; 0.73 ± 0.08 at progesterone peak; p > 0.05), as did bleeding on probing (0.35 ± 0.07 at ovulation; 0.41 ± 0.07 at progesterone peak; p > 0.05). At ovulation, mean gingival crevicular fluid levels were as follows: IL-1β, 13.3 pg/sample; IL-6, 5.9 pg/sample; IL-8, 18.7 pg/sample; and TNF-α, 25.9 pg/sample. The corresponding values at progesterone peak were as follows: 14.1, 10.1, 19.5 and 26.3 pg/sample. Only IL-6 gingival crevicular fluid levels were significantly different between ovulation and progesterone peak (p < 0.05). This could reflect sensitivity to subclinical amounts of plaque and biofilm constituents. CONCLUSION The subclinical increase of IL-6 at progesterone peak is not accompanied by clinical changes in the periodontium.

Cystic angiomatosis of bone: A case report

Diffuse skeletal cystic angiomatosis is an extremely rare disorder that has not previously been reported in detail in the dental literature. This case report deals with the oral manifestations in a 10-year-old boy. Clinical, radiographic, and computed tomographic examinations showed hyperplasia of the right side of the face. The computed tomographic imaging studies revealed the extent of the jawbone lesions and the adjacent hyperplastic soft tissues. The histologic appearance of the lesions, the course of the disease, and the differential diagnosis are discussed.

Control of dentin/root sensitivity during non-surgical and surgical periodontal treatment

AIM To determine the efficacy of a desensitizing regimen compared to a control in preventing the occurrence and/or alleviating dentin/root sensitivity (DRS) following non-surgical (NSPT) and surgical periodontal treatment (SPT). METHODS Seventy-four chronic-periodontitis patients (CPP) were randomized into a test group (n = 38) using an in-office prophylaxis paste and a toothpaste at home both containing 8% arginine and calcium carbonate (Pro-Argin(™) Technology) or into a control group (n = 36) receiving a fluoride-free prophylaxis paste and a fluoride toothpaste. The examiner applied the assigned paste onto selected teeth for 3 s following NSPT and for 60 s before flap closure. Patients brushed with the assigned toothpaste twice daily throughout the study. DRS to air stimulus was assessed by the Schiff scale (0-3) and the Visual Analog Scale (VAS: 0-100 mm) six times over 17 weeks. RESULTS In the test group, VAS scores significantly decreased at 8, 11 and 17 weeks from baseline (p ≤ 0.003) and Schiff scores at 8 and 11 weeks from baseline (p ≤ 0.014). The control group exhibited significant increases in VAS and Schiff during the study period (p ≤ 0.006). Marked inter-group differences were noted at all time points (p < 0.001). CONCLUSIONS The combined use of desensitizing products (8% arginine and calcium carbonate) in-office and at-home prevented DRS development and maintained this effect for 17 weeks following NSPT and SPT.

Stem cell-like populations and immunoregulatory molecules in periodontal granulation tissue

BACKGROUND AND OBJECTIVES Determine the presence of mesenchymal stem cells (MSCs) in healthy periodontal tissue and periodontal granulation tissue (GT) and explore associations between immuno-regulatory molecules and selected subgingival microorganisms. MATERIAL AND METHODS Mesenchymal stem cells were isolated, propagated and characterised by flow cytometry from a region of healthy gingival tissue and inflamed GT of 10 systemically healthy non-smokers with chronic periodontitis. Tissue levels of immunoregulatory molecules were determined by qPCR and Gingival Crevicular Fluid (GCF) levels by ELISA. Subgingival plaque levels of periodontal pathogens were determined by qPCR RESULTS: Cells with MSC-properties were isolated from both inflamed GT and healthy gingival (G) tissue. A pro-inflammatory process predominated in GT which was partly reflected in GCF and putative periodontal pathogens were higher at diseased sites. However, there was no significant difference in surface levels of mesenchymal (CD90, CD73, CD146, CD271, STRO-1), endothelial (CD105, CD106), hematopoietic (CD34, CD45) and embryonic (SSEA-4) stem cell markers between MSCs isolated from GT and G tissue. CONCLUSION Periodontal lesions, albeit inflamed, retain healing potential as inferred by the presence of MSC-like cells with similar immunophenotypic characteristics to those found in healthy periodontal tissue. Therefore, there might be merits for healing in preserving sufficient GT in-situ during periodontal surgery.

Microbiome of peri-implantitis affected and healthy dental sites in patients with a history of chronic periodontitis

OBJECTIVE To determine the composition of the microbiome of peri-implantitis sites and corresponding dental sites in subjects with a history of chronic periodontitis. DESIGN Clinical and radiographic examination assessed the periodontal/peri-implant disease status. Plaque samples were collected from one diseased implant with peri-implantitis, functional for at least two years and healthy sites in ten non-smokers who had received periodontal treatment prior to implant placement. Following DNA extraction, the bacteria present in each sample were determined by high-throughput sequencing of V3-V4 region of the 16S rRNA gene using the Illumina MiSeq platform. OTUs were picked using QIIME. Differences between dental and implant sites were determined using linear discriminant analysis, effect size and diversity analyses were conducted using PAST v3.02. RESULTS The microbiomes of healthy samples were more diverse than those found in disease, although disease was associated with a higher abundance of taxa relative to health. The genera Actinobacillus and Streptococcus were most closely associated with health, whereas Prevotella and Porphyromonas were most discriminative for disease. Synergistetes were highly associated with peri-implantitis. CONCLUSION In patients with a history of periodontitis, putative periodontal pathogens prevailed in the microbiome of diseased implants. Diseased implants and corresponding healthy sites appear to have distinct microbiological ecosystems.

Immunological and microbiological findings after the application of two periodontal surgical techniques: a randomized, controlled clinical trial.

AIM To examine microbiological and immunological alterations following two periodontal surgical techniques, over a 6-month period. MATERIALS AND METHODS A total of 30 chronic periodontitis patients participated in the present randomized controlled clinical trial and were randomized in two groups. Modified Widman flap (MWF) was applied in the control group and apically positioned flap (APF), without intervention to the bone, in the experimental group. Gingival crevicular fluid samples and subgingival plaque samples from the operated sites were collected at baseline, 6th, 12th and 24th post-operative week. RESULTS No major differences were noticed in immunological and microbiological profile of patients receiving either modified MWF or APF, for a period of 6 months. CONCLUSIONS The choice of the periodontal surgical procedure does not seem to affect the immunological and the microbiological profile of patients with chronic periodontitis.

Clinical associations between acetylcholine levels and cholinesterase activity in saliva and gingival crevicular fluid and periodontal diseases

AIM The oral mucosa possesses a non-neuronal cholinergic system. This study aimed to determine clinical evidence for a role of cholinergic mechanisms in the pathogenesis of periodontal diseases. MATERIALS AND METHODS Fifty healthy participants, 52 patients with gingivitis and 49 with periodontitis were recruited. Full periodontal parameters were recorded and saliva and gingival crevicular fluid (GCF) collected. Levels of acetylcholine and inflammatory mediators were quantified using commercially available assay kits. Acetylcholinesterase and butyrylcholinesterase activities were measured using a published biochemical assay. RESULTS Acetylcholine levels are significantly elevated in saliva and GCF, whereas GCF levels of butyrylcholinesterase activity are significantly decreased, in patients with periodontal diseases. Acetylcholine levels in saliva and GCF correlated positively with clinical markers of disease severity and with increased levels of IL-17A and IL-17F. In contrast, butyrylcholinesterase activity levels in GCF showed significant negative correlations with clinical markers of disease severity and IL-17A and IL-17F levels. None of the findings were due to smoking. CONCLUSIONS Elevated acetylcholine levels and reduced butyrylcholinesterase activity are clinically associated with periodontal diseases and elevated levels of IL-17A and IL-17F. Therefore, non-neuronal cholinergic mechanisms may influence IL-17 biology and the aetiopathogenesis of periodontal diseases and therefore are possible therapeutic targets.

Microbiome associated with peri-implantitis versus periodontal health in individuals with a history of periodontal disease

ABSTRACT The microbiome of peri-implantitis sites and healthy dental sites was determined in subjects with a history of periodontitis. Ten systemically healthy non-smokers received periodontal treatment before implant placement. Plaque samples were collected from four sites of one implant with peri-implantitis (bone loss ≥2mm; PPD ≥6mm; BOP/suppuration; >1year loading) and from one dental site per quadrant with periodontal health (PPD ≤3mm, CAL <4mm, absence of BOP and bone loss). Following DNA extraction, the bacteria present in each sample were determined by high-throughput sequencing of the V3-V4 region of the 16S-rRNA gene using the Illumina-MiSeq platform. OTUs were picked using QIIME. Differences between dental and implant sites were determined using linear discriminant analysis, effect size and diversity analyses were conducted using PAST v3.02. The microbiomes of diseased samples were less diverse than those found in health, although disease was associated with a higher abundance of taxa relative to health. The genera Actinobacillus and Streptococcus were most closely associated with health, whereas Prevotella and Porphyromonas were most discriminative for disease. Other disease associated genera were Peptostreptococcus, Tannerella, Treponema, TG5 and Atopobium. Diseased peri-implant and healthy periodontal tissues in the same individual appear to harbour distinct microbiological ecosystems with putative periodontal pathogens predominating in the peri-implantitis-associated microbiome.