Poliana Mendes Duarte

Short‐term clinical and microbiological evaluations of peri‐implant diseases before and after mechanical anti‐infective therapies

OBJECTIVES The aim of this study was to evaluate the clinical and microbiological effects of mechanical anti-infective therapies for mucositis and peri-implantitis. MATERIAL AND METHODS Subjects with at least one dental implant were assigned to healthy (n=10), mucositis (n=12) or peri-implantitis (n=13) groups. Implants with mucositis or peri-implantitis were decontaminated by means of teflon curettes and abrasive sodium carbonate air-powder, performed by an open flap for peri-implantitis and without surgery for mucositis. Visible plaque (PI), marginal bleeding (MB), bleeding on probing (BOP), suppuration (SUP), probing depth (PD) and relative clinical attachment level (rCAL) were assessed at baseline and at 3 months after therapies. At the same time points, submucosal plaque samples were collected from each implant and analyzed by Checkerboard DNA-DNA hybridization for 40 bacterial species. RESULTS All clinical parameters improved at 3 months post-therapy in mucositis and peri-implantitis groups (P<0.05). The mean reduction in rCAL (+/-SD) was 1.4+/-1.2 mm and 2.3+/-1.6 mm, and it was 1.3+/-1.2 mm and 3.1+/-1.7 mm in PD (+/-SD) for mucositis and peri-implantitis, respectively. Levels of Treponema denticola, Tanerella forsythia and Parvimonas micra, and of Fusobacterium nucleatum ss nucleatum, were significantly reduced after peri-implantitis therapy and after mucositis therapy, respectively (P<0.05). In addition, counts of Porphyromons gingivalis, Treponema socranskii and the proportions of red complex were reduced in both groups at 3 months after treatments (P<0.05). CONCLUSION Mechanical therapies alone were effective in treating mucositis and peri-implantitis over a period of 3 months. The open debridement procedure showed clinical and microbiological benefits on the treatment of peri-implantitis and could be safely used as a standard control group for future studies.

Microbiological profile of untreated subjects with localized aggressive periodontitis

AIM The microbial profile of localized aggressive periodontitis (LAgP) has not yet been determined. Therefore, the aim of this study was to evaluate the subgingival microbial composition of LAgP. MATERIAL AND METHODS One hundred and twenty subjects with LAgP (n=15), generalized aggressive periodontitis (GAgP, n=25), chronic periodontitis (ChP, n=30) or periodontal health (PH, n=50) underwent clinical and microbiological assessment. Nine subgingival plaque samples were collected from each subject and analysed for their content of 38 bacterial species using checkerboard DNA-DNA hybridization. RESULTS Red complex and some orange complex species are the most numerous and prevalent periodontal pathogens in LAgP. The proportions of Aggregatibacter actinomycetemcomitans were elevated in shallow and intermediate pockets of LAgP subjects in comparison with those with GAgP or ChP, but not in deep sites. This species also showed a negative correlation with age and with the proportions of red complex pathogens. The host-compatible Actinomyces species were reduced in LAgP. CONCLUSION A. actinomycetemcomitans seems to be associated with the onset of LAgP, and Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Campylobacter gracilis, Eubacterium nodatum and Prevotella intermedia play an important role in disease progression. Successful treatment of LAgP would involve a reduction in these pathogens and an increase in the Actinomyces species.

Short‐term benefits of the adjunctive use of metronidazole plus amoxicillin in the microbial profile and in the clinical parameters of subjects with generalized aggressive periodontitis

AIM The aim of this study was to evaluate the clinical and microbiological effects of scaling and root planing (SRP) alone or combined with metronidazole (MTZ) and amoxicillin (AMX) in the treatment of subjects with generalized aggressive periodontitis (GAgP). MATERIALS AND METHODS A double-blind, placebo-controlled, randomized clinical trial was conducted in 30 subjects receiving SRP alone or combined with MTZ (400 mg 3 x per day) and AMX (500 mg 3 x per day) for 14 days. Clinical and microbiological examinations were performed at baseline and 3 months post-SRP. Nine subgingival plaque samples per subject were analysed using checkerboard DNA-DNA hybridization. RESULTS Subjects receiving MTZ and AMX showed the greatest improvements in the mean full-mouth probing depth and clinical attachment level and at initially intermediate and deep sites. The most beneficial changes in the microbial profile were also observed in the MTZ+AMX group, which showed the lowest proportions of the red complex as well as a significant decrease in the proportions of the orange complex after treatment. The antibiotic therapy also reduced the levels of Aggregatibacter actinomycetemcomitans at initially deep sites. CONCLUSION Subjects with GAgP significantly benefit from the adjunctive use of MTZ and AMX. The short-term advantages are observed in the clinical and microbiological parameters.

Serum Levels of Cytokines in Subjects With Generalized Chronic and Aggressive Periodontitis Before and After Non-Surgical Periodontal Therapy: A Pilot Study

BACKGROUND The emergence of periodontal medicine has increased interest in defining the serologic profiles of inflammatory mediators in subjects with periodontitis. Thus, the aim of this pilot study is to evaluate the serum levels of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma, and interleukin (IL)-4, -17, and -23 in subjects with generalized chronic periodontitis (GCP) and generalized aggressive periodontitis (GAgP) before and after non-surgical periodontal therapy. METHODS Cytokines were measured by enzyme-linked immunosorbent assay in serum samples taken from 42 systemically healthy subjects divided according to periodontal status into subjects with GAgP (n = 14) and GCP (n = 14) and periodontally healthy (PH) subjects (n = 14). In addition, the levels of cytokines were reassessed at 6 months after periodontal therapy in the periodontitis groups. Clinical parameters were also evaluated at baseline and 6 months post-therapy. RESULTS After therapy, both periodontitis groups demonstrated a significant improvement in clinical periodontal status (P <0.05). At baseline, concentrations of TNF-alpha (P = 0.0006) and IL-17 (P = 0.02) were significantly higher in the GAgP group compared to the other groups. There was a significant decrease in serum concentrations of TNF-alpha (P = 0.03) and IL-17 (P = 0.04) at 6 months post-therapy in the GAgP group (P <0.05). The concentration of TNF-alpha remained elevated in the GAgP group compared to the PH group at 6 months post-therapy (P = 0.04). CONCLUSIONS Subjects with GAgP presented higher levels of TNF-alpha and IL-17 than subjects with GCP and PH subjects. In addition, although the serum levels of these cytokines improved significantly as a result of periodontal therapy, the levels of TNF-alpha remained higher in subjects with GAgP compared to PH subjects.

Mechanisms of action of systemic antibiotics used in periodontal treatment and mechanisms of bacterial resistance to these drugs

Antibiotics are important adjuncts in the treatment of infectious diseases, including periodontitis. The most severe criticisms to the indiscriminate use of these drugs are their side effects and, especially, the development of bacterial resistance. The knowledge of the biological mechanisms involved with the antibiotic usage would help the medical and dental communities to overcome these two problems. Therefore, the aim of this manuscript was to review the mechanisms of action of the antibiotics most commonly used in the periodontal treatment (i.e. penicillin, tetracycline, macrolide and metronidazole) and the main mechanisms of bacterial resistance to these drugs. Antimicrobial resistance can be classified into three groups: intrinsic, mutational and acquired. Penicillin, tetracycline and erythromycin are broad-spectrum drugs, effective against gram-positive and gram-negative microorganisms. Bacterial resistance to penicillin may occur due to diminished permeability of the bacterial cell to the antibiotic; alteration of the penicillin-binding proteins, or production of β-lactamases. However, a very small proportion of the subgingival microbiota is resistant to penicillins. Bacteria become resistant to tetracyclines or macrolides by limiting their access to the cell, by altering the ribosome in order to prevent effective binding of the drug, or by producing tetracycline/macrolide-inactivating enzymes. Periodontal pathogens may become resistant to these drugs. Finally, metronidazole can be considered a prodrug in the sense that it requires metabolic activation by strict anaerobe microorganisms. Acquired resistance to this drug has rarely been reported. Due to these low rates of resistance and to its high activity against the gram-negative anaerobic bacterial species, metronidazole is a promising drug for treating periodontal infections.

Bacterial Adhesion on Smooth and Rough Titanium Surfaces After Treatment With Different Instruments

BACKGROUND Newly formed biofilm after implant debridement may challenge the long-term stability of peri-implant therapy. This in vitro study aimed to assess the roughness and adherence of Streptococcus sanguinis after treatment of smooth and rough titanium surfaces with an erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser, metal and plastic curets, and an air-powder abrasive system. METHODS Forty titanium disks with smooth-machined surfaces and 40 with sand-blasted and acid-etched surfaces were divided into the following treatment groups: Er:YAG laser; plastic curet; metal curet, and air-powder abrasive system. The surface roughness (roughness average [Ra]) before and after treatments was determined using a profilometer. S. sanguinis (American Type Culture Collection 10556) was grown on treated and untreated specimens, and the amounts of retained bacteria on the surfaces were measured by the culture method. Rough and smooth surfaces with and without a suspension of S. sanguinis were also analyzed using scanning electron microscopy (SEM). RESULTS For smooth surfaces, the roughest surfaces were produced by metal curets (repeated-measures analysis of variance [ANOVA] and Tukey test; P <0.05). The rough-surface profile was not altered by any of the treatments (repeated-measures ANOVA; P >0.05). Rough surfaces treated with metal curets and air-powder abrasion showed the lowest level of bacterial adhesion (two-way ANOVA and Tukey test; P <0.05). SEM analysis revealed distinct surface profiles produced by all devices. CONCLUSIONS Metal curets are not recommended for smooth titanium surface debridement due to severe texture alteration. Rough surfaces treated with a metal curet and the air-powder abrasive system were less susceptible to bacterial adhesion, probably due to texture modification and the presence of abrasive deposits.

Differential cytokine expressions affect the severity of peri‐implant disease

OBJECTIVE This study assessed gene expression by quantitative polymerase chain reaction of inflammatory- [interleukin (IL)-12, tumor necrosis factor-alpha (TNF-alpha), IL-4, and IL-10] and osteoclastogenesis-related factors [receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG)] in sites exhibiting different severities of peri-implant disease. MATERIAL AND METHODS Peri-implant soft tissue biopsies (n=48) were harvested from healthy implant (HI), mucositis (MC), initial peri-implantitis (IP) and severe peri-implantitis (SP) sites. RESULTS IL-12 and TNF-alpha mRNA levels were higher in SP, followed by IP and MC (P <0.05). IL-4 was higher in HI, followed by MC, SP and IP (P <0.05). IL-10 was the lowest in HI, while no differences were detected among the diseased groups (P>0.05). OPG mRNA levels were higher in HI, followed by IP, SP and MC, whereas RANKL was increased as the peri-implantitis severity increased (P<0.05). The highest OPG/RANKL ratio was observed in HI and the lowest in SP (P<0.01). CONCLUSION These findings suggest that expressions of inflammatory- and osteoclastogenesis-related factors may play an important role in the onset and severity of the peri-implant diseases.

Subgingival biodiversity in subjects with uncontrolled type‐2 diabetes and chronic periodontitis

BACKGROUND AND OBJECTIVE There is a bidirectional relationship between periodontal disease and type-2 diabetes mellitus (DM). Inflammatory mediators may negatively affect glycemic control, and increased glucose levels and resultant glycation end-products may alter the host response against bacterial infection. However, no agreement has been reached regarding the effect of DM on periodontal subgingival microbiota. Therefore, the purpose of the present study was to compare the subgingival biodiversity in deep periodontal pockets of subjects with chronic periodontitis and either uncontrolled type-2 diabetes or no diabetes using 16S rRNA gene cloning and sequencing. MATERIAL AND METHODS Twelve subjects with uncontrolled type-2 diabetes (glycated hemoglobin > 8%) and eleven nondiabetic subjects presenting severe and generalized chronic periodontitis were selected. Subgingival biofilm from periodontal pockets > 5 mm were assessed using the 16S rRNA gene cloning and sequencing technique. RESULTS Significant differences were observed in subgingival microbiota between diabetic and nondiabetic subjects. Diabetic subjects presented higher percentages of total clones of TM7, Aggregatibacter, Neisseria, Gemella, Eikenella, Selenomonas, Actinomyces, Capnocytophaga, Fusobacterium, Veillonella and Streptococcus genera, and lower percentages of Porphyromonas, Filifactor, Eubacterium, Synergistetes, Tannerella and Treponema genera than nondiabetic individuals (p < 0.05). Moreover, some phylotypes, such as Fusobacterium nucleatum, Veillonella parvula, V. dispar and Eikenella corrodens were detected significantly more often in diabetic subjects than in nondiabetic subjects (p < 0.05). CONCLUSION Subjects with uncontrolled type-2 diabetes and chronic periodontitis presented significant dissimilarities in subgingival biodiversity compared with nondiabetic subjects.

Local and Circulating Levels of Adipocytokines in Obese and Normal Weight Individuals With Chronic Periodontitis

BACKGROUND The aim of this study is to evaluate the local and circulating levels of adipocytokines (resistin, adiponectin, leptin, tumor necrosis factor [TNF]-α, and interleukin [IL]-6) in individuals who are obese and individuals who are normal weight (NW) with chronic periodontitis (CP). METHODS Periodontal and anthropometric examinations were performed. Based on these measurements, the individuals were divided into one of the following groups: NW non-periodontitis (NP) (NWNP; n = 20); NWCP (n = 20); obese NP (ONP; n = 18); and obese CP (OCP; n = 20). The levels of adipocytokines were evaluated in the serum and gingival crevicular fluid of shallow and deep sites by enzyme-linked immunosorbent assay. RESULTS In serum, resistin levels were higher whereas adiponectin levels were lower in periodontitis than in NP groups (P <0.05). The NWNP group presented the lowest serum leptin levels (P <0.05). The ONP and OCP groups demonstrated higher TNF-α levels in periodontal sites than the NWNP and NWCP groups (P <0.05). Serum levels of IL-6 (P = 0.04) and leptin (P = 0.01) were correlated with the OCP group, with odds ratios of 0.99 (95% confidence interval [CI]: -0.01 to -0.00) and 0.99 (95% CI: -0.00 to -0.00), respectively. CONCLUSIONS Periodontitis mainly influenced the circulating levels of resistin and adiponectin, whereas both obesity and periodontitis affected the circulating levels of leptin in favor of proinflammation. In addition, obesity upregulated the local levels of TNF-α.

Cytokines and Bone-Related Factors in Systemically Healthy Patients With Chronic Periodontitis and Patients With Type 2 Diabetes and Chronic Periodontitis

BACKGROUND This study compares the levels of cytokines and bone-related factors in the gingival crevicular fluid (GCF) of systemically healthy patients with chronic periodontitis (CP); and better-controlled, and poorly controlled patients with type 2 diabetes and CP. METHODS Thirty-seven patients with type 2 diabetes and CP and 20 systemically healthy patients with CP were enrolled in this study. The patients with diabetes mellitus were categorized as better-controlled (n = 17; HbA(1c) levels ≤8%) or poorly controlled (n = 20; glycated hemoglobin values >8%). Levels of tumor necrosis factor-α, interleukin (IL)-4, interferon (IFN)-γ, IL-23, IL-17, soluble receptor activator of nuclear factor-kappa B ligand (sRANKL), and osteoprotegerin (OPG) in GCF of diseased sites were analyzed by enzyme-linked immunosorbent assay. RESULTS Type 2 diabetes mellitus, as a whole, upregulates the levels of OPG, sRANKL, IFN-γ, IL-17, and IL-23 and downregulates the production of IL-4 in sites with CP (P <0.05). Better-controlled individuals exhibited the highest levels of IFN-γ, whereas poorly controlled patients presented the highest levels of IL-17 (P <0.05). There were no differences in the levels of tumor necrosis factor-α, OPG, and IL-23 among systemically healthy, better-controlled, and poorly controlled patients with diabetes (P >0.05). CONCLUSIONS Increased levels of proinflammatory cytokines and RANKL were observed in the GCF of patients with type 2 diabetes with CP, compared to patients without diabetes. In addition, poor or good glycemic status seems to modulate osteo-immunoinflammatory mediators in a different manner.