Protein biomarkers and microbial profiles in peri-implantitis.

OBJECTIVES: The aim of the present investigation was to determine the profile of peri-implant crevicular fluid (PICF) biomarkers combined with microbial profiles from implants with healthy peri-implant tissues and peri-implantitis to assess real-time disease activity. MATERIAL AND METHODS: Sixty-eight patients were included in this cross-sectional study. They were divided into two groups: 34 patients with at least one healthy implant (control) and 34 with at least one peri-implantitis affected implant (test). Total DNA content and qPCR analysis for periodontal bacteria obtained from subgingival plaque samples (Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) and a PICF analysis for IL-1ß, VEGF, MMP-8, TIMP-2, and OPG were performed. The individual and combined diagnostic ability of each biomarker for peri-implantitis and target bacterial species were analyzed. RESULTS: The mean concentration of IL-1ß (44.6 vs. 135.8 pg/ml; P < 0.001), TIMP-2 (5488.3 vs. 9771.8 pg/ml; P = 0.001), VEGF (59.1 vs. 129.0 pg/ml; P = 0.012), and OPG (66.5 vs. 111.7 pg/ml; P = 0.050) was increased in the peri-implantitis patients. The mean expression of MMP-8 (6029.2 vs. 5943.1 pg/ml; P = 0.454) and did not reveal a meaningful difference among groups. Total bacterial DNA of selected microorganisms was associated with a threefold or greater increase in peri-implantitis although no statistical significant difference. The ability to diagnose diseased sites was enhanced by T. denticola combined with IL-1ß, VEGF, and TIMP-2 PICF levels. CONCLUSION: The present data suggest that the increased levels of the selected PICF-derived biomarkers of periodontal tissue inflammation, matrix degradation/regulation, and alveolar bone turnover/resorption combined with site-specific microbial profiles may be associated with peri-implantitis and could have potential as predictors of peri-implant diseases.

Deoxyribonucleic Acid Probes Analyses for the Detection of Periodontal Pathogens.

BACKGROUND: In clinical microbiology several techniques have been used to identify bacteria. Recently, Deoxyribonucleic acid (DNA)-based techniques have been introduced to detect human microbial pathogens in periodontal diseases. Deoxyribonucleic acid probes can detect bacteria at a very low level if we compared with the culture methods. These probes have shown rapid and cost-effective microbial diagnosis, good sensitivity and specificity for some periodontal pathogens in cases of severe periodontitis. MATERIALS AND METHODS: Eighty-five patients were recruited for the study. Twenty-one subjects ranging between 22 and 48 years of age fulfilled the inclusion and exclusion criteria. Seventy-eight samples became available for DNA probe analysis from the deepest pockets in each quadrant. RESULTS: All 21 patients showed positive results for Prevotella intermedia; also, Prevotella gingivalis was identified in 19 subjects, Aggregatibacter actinomycetemcomitans in 6 subjects. P. intermedia was diagnosed positive in 82% of the subgingival samples taken, 79% for P. gingivalis, and 23% for A. actinomycetemcomitans. CONCLUSION: This study shows a high frequency of putative periodontal pathogens by using DNA probe technology, which is semi-quantitative in this study. Deoxyribonucleic acid probes can detect bacteria at very low level about 10(3) which is below the detection level of culture methods. The detection threshold of cultural methods. CLINICAL SIGNIFICANCE: The three types of bacteria can be detected rapidly with high sensitivity by using the DNA probe by general practitioners, and thus can help in the diagnosis process and the treatment.

Pilot study on the clinical and microbiological effect of subgingival glycine powder air polishing using a cannula-like jet.

OBJECTIVES: To assess the efficacy of subgingival glycine powder air polishing (GPAP) during supportive periodontal therapy (SPT). METHODS: Each quadrant of 25 subjects was randomly assigned to the following treatments: subgingival scaling with hand instruments (SRP), GPAP, subgingival ultrasonic debridement (UD) and no subgingival treatment (NT). Clinical recordings included the following: probing pocket depth (PPD), gingival recession (RE), clinical attachment level (CAL), Gingival and Plaque Index. Subgingival plaque samples were taken from two sites >4 mm per quadrant. Therapy, recordings and microbial sampling were performed at baseline, 3 and 6 months, while at 1 month only clinical recordings and sampling were performed. Subgingival samples were analysed using 'checkerboard' DNA-DNA hybridization for Porphyromonas gingivalis, Tannerrella forsythia and Treponema denticola. RESULTS: All groups were homogeneous at baseline for the clinical parameters assessed. The GPAP group displayed statistically significant higher PPD compared to SRP and UD at 1, 3 and 6 months and no statistical differences with the 'no treatment' group at all time points. At 1 month, the GPAP group displayed statistically significantly higher levels of CAL compared to SRP, while at 3 and 6 months statistically significant differences were observed with groups assigned to SRP and UD. No differences were observed among groups for RE, PI, GI and numbers of the investigated bacteria at any time point. CONCLUSIONS: On the basis of clinical and microbiological data, this study does not support the superiority of GPAP as sole treatment over SRP or subgingival ultrasonic scaling.

Effects of doxycycline on clinical, microbiological and immunological parameters in well-controlled diabetes type-2 patients with periodontal disease: a randomized, controlled clinical trial.

AIM: To evaluate the clinical, microbiological and immunological effects of systemic doxycycline as an adjunct to scaling and root planing (SRP) in chronic periodontitis patients with well-controlled type 2 diabetes. MATERIALS AND METHODS: Sixty-six patients compliant to oral hygiene (Hygiene Index <20%) allocated to either a test (systemic doxycycline for 21 days) or a control (placebo) group participated in the present randomized controlled trial (RCT). Clinical assessments were recorded at baseline, 3 and 6 months after therapy and included clinical attachment level (CAL), set as the primary outcome of the study, probing pocket depth (PPD), recession (RE) and bleeding on probing (BOP). At the same time points, counts of 15 subgingival species were evaluated by "checkerboard" DNA-DNA hybridization, gingival crevicular fluid samples were analysed for matrix metalloproteinase-8 (MMP-8) by ELISA and HbA1c levels were determined. Comparisons between and within groups were performed by non-parametric tests (Mann-Whitney, Wilcoxon signed-ranks and z-test for proportions with Bonferroni corrections) at the 0.05 level. RESULTS: No major differences were noticed in clinical and microbiological parameters of periodontal disease or levels of MMP-8 between the two groups. CONCLUSIONS: Adjunctive systemic doxycycline does not seem to significantly enhance the effects of SRP in well-controlled diabetes type 2 patients.

Differential expression of mitogen activating protein kinases in periodontitis.

AIM: Following toll-like receptor (TLR) engagement, lipopolysaccharide (LPS) can stimulate the expression of pro-inflammatory cytokines thus activating the innate immune response. The production of inflammatory cytokines results, in part, from the activation of kinase-induced signalling cascades and transcriptional factors. Of the four distinct classes of mitogen-activated protein kinases (MAPK) described in mammals, p38, c-Jun N-terminal activated kinases (JNK1-3) and extracellular activated kinases (ERK1,2) are the best studied. Previous data have established that p38 MAPK signalling is required for inflammation and bone loss in periodontal disease pre-clinical animal models. MATERIALS & METHODS: In this study, we obtained healthy and diseased periodontal tissues along with clinical parameters and microbiological parameters. Excised fixed tissues were immunostained with total and phospho-specific antibodies against p38, JNK and ERK kinases. RESULTS: Intensity scoring from immunostained tissues was correlated with clinical periodontal parameters. Rank correlations with clinical indices were statistically significantly positive (p-value < 0.05) for total p38 (correlations ranging 0.49-0.68), phospho-p38 (range 0.44-0.56), and total ERK (range 0.52-0.59) levels, and correlations with JNK levels also supported association (range 0.42-0.59). Phospho-JNK and phospho-ERK showed no significant positive correlation with clinical parameters of disease. CONCLUSION: These data strongly implicate p38 MAPK as a major MAPK involved in human periodontal inflammation and severity.

Connective tissue graft plus resin-modified glass ionomer restoration for the treatment of gingival recession associated with non-carious cervical lesions: microbiological and immunological results.

OBJECTIVES: It was previously reported the clinical results of placing subgingival resin-modified glass ionomer restoration for treatment of gingival recession associated with non-carious cervical lesions. The aim of this study was to evaluate the influence of this treatment on the subgingival biofilm and gingival crevicular fluid (GCF) inflammatory markers. MATERIALS AND METHODS: Thirty-four patients presenting the combined defect were selected. The defects were treated with either connective tissue graft plus modified glass ionomer restoration (CTG+R) or with connective tissue graft only (CTG). Evaluation included bleeding on probing and probing depth, 5 different bacteria targets in the subgingival plaque assessed at baseline, 45, and 180 days post treatments, and 9 inflammatory mediators were also assessed in the GCF. RESULTS: The levels of each target bacterium were similar during the entire period of evaluation (p > 0.05), both within and between groups. The highest levels among the studied species were observed for the bacterium associated with periodontal health. Additionally, the levels of all cyto/chemokines analyzed were not statistically different between groups (p > 0.05). CONCLUSION: Within the limits of the present study, it can be concluded that the presence of subgingival restoration may not interfere with the subgingival microflora and with GCF inflammatory markers analyzed. CLINICAL RELEVANCE: This approach usually leads to the placement of a subgingival restoration. There is a lack of information about the microbiological and immunological effects of this procedure. The results suggest that this combined approach may be considered as a treatment option for the lesion included in this study.

A randomized clinical trial on the clinical and microbiological efficacy of a xanthan gel with chlorhexidine for subgingival use.

BACKGROUND: The main indication of the adjunctive use of local antimicrobials lies around situations in which the outcome of non-surgical mechanical treatment results in a limited number of residual pockets. The purpose of this investigation was to evaluate the clinical and microbiological effects of the subgingival application of a xanthan-based 1.5% chlorhexidine (CHX) gel (Xan-CHX), adjunctive to scaling and root planing (SRP) in localized periodontitis. METHODS: Periodontitis patients with four to ten residual (after conventional SRP) or relapsing (during supportive periodontal treatment) pockets were recruited and randomized to receive SRP plus the subgingival application of (Xan-CHX) or SRP plus a placebo gel. Supragingival plaque, bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment level were evaluated with a computerized probe at baseline, and after 1, 3, and 6 months. Subgingival samples were also collected for the microbiological analysis. Statistical analysis used ANOVA and chi-square tests. RESULTS: Overall, the clinical results were better in the test group, with significant changes in BOP (between baseline and 3 months) and with a significant increase in the proportion of shallow pockets (1-3 mm) at 6 months. These results did not result in significant intergroup differences. The microbiological impact was limited in both treatment groups. CONCLUSION: The adjunctive use of Xan-CHX may improve, although to a limited extent, the clinical outcomes (BOP and PPD), in chronic periodontitis patients with "residual" or "relapsing" pockets, but no significant differences were detected between groups. No side effects, neither clinical nor microbiological, were detected after the use of the test product. CLINICAL RELEVANCE: Adjunctive use of slow-released chlorhexidine might be considered in the management of periodontal disease and gingival inflammation to reduce the need for periodontal surgery.

Isolation and identification of Porphyromonas spp. and other putative pathogens from cats with periodontal disease.

The purpose of this study was to evaluate the subgingival microbiota and determine the most prevalent periodontal pathogens implicated in feline periodontal disease and to correlate these findings with the clinical periodontal status. Subgingival microbiological samples were taken under sedation from 50 cats with clinical signs of periodontal disease. Pooled paper point samples from 4 selected subgingival sites were cultured on blood agar and on Dentaid-1 medium. Suspected pathogens were identified, subcultured, and preserved. The association between the microbiological findings and the clinical status was studied using correlation coefficients (CC). In addition, cats were stratified in subgroups according to presence of putative pathogens, and comparisons were carried out using unpaired t-test. Three bacterial species were frequently detected including Porphyromonas gulae (86%), Porphyromonas circumdentaria (70%) and Fusobacterium nucleatum (90%). The mean proportion of total flora was high for P. gulae (32.54%), moderate for P. circundentaria (8.82%), and low for F. nucleatum (3.96%). Among the clinical variables, tooth mobility was correlated (CC > 0.50, p < 0.001) with recession, pocket depth, attachment level, gingival index, and calculus index (CC = 0.29, p = 0.04) as well as with total bacterial counts (CC = 0.38, p = 0.006). Cats with more than 10% of P. gulae showed significantly more mobility (p = 0.014) and recession (p = 0.038), and a tendency for deeper probing pocket depths (p = 0.084) and attachment loss (p = 0.087). The results from this cross-sectional study confirmed that P. gulae is the most relevant pathogen in periodontal disease in cats.

Comparing culture, real-time PCR and fluorescence resonance energy transfer technology for detection of Porphyromonas gingivalis in patients with or without peri-implant infections.

BACKGROUND AND OBJECTIVE: The aim of the study was to compare the detection of Porphyromonas gingivalis using a fluorescence resonance energy transfer (FRET) technology with commonly used diagnostic methods in salivary and subgingival plaque samples from subjects with dental implants. P. gingivalis was considered as a marker for a pathogenic microbiota. MATERIAL AND METHODS: Ninety-seven adult subjects were recruited, including periodontally healthy controls with no dental implants, implant controls with no peri-implant disease and patients with peri-implant disease. Saliva and subgingival/submucosal plaque samples were collected from all subjects and were analyzed using culture, real-time PCR and FRET technology employing P. gingivalis-specific substrates. RESULTS: It was found that the P. gingivalis-specific substrates were highly suitable for detecting the presence of P. gingivalis in saliva and in subgingival plaque samples, showing comparable specificity to culture and real-time PCR. CONCLUSION: We applied the FRET technology to detect P. gingivalis in implant patients with or without an implant condition and in controls without implants. The technique seems suitable for detection of P. gingivalis in both plaque and saliva samples. However, with all three techniques, P. gingivalis was not very specific for peri-implantitis cases. Future work includes fine-tuning the FRET technology and also includes the development of a chair-side application.

A Review of the Role of Probiotic Supplementation in Dental Caries.

Dental diseases are among the common health issues experienced around the world. Dental caries is one of the most predominant oral diseases worldwide. Major factors associated with caries development include poor oral hygiene, the content of specific carbohydrates in the diet, dental biofilm formation, the cariogenic microbial load, reduction in salivary flow, insufficient fluoride exposure, gingival recession, genetic factors, and lack of personal attention to one's dental health. Several preventive measures have been implemented to reduce the risk of the development of caries. Probiotics are live microbes that when administered in suitable amounts confer health benefits on the host; they are recognized as potential adjunct therapeutic agents for several diseases. The present manuscript summarizes recent findings on the role of probiotics in dental caries prevention and the possible mechanisms of probiotic effects. Review of the literature indicates the regular consumption of probiotic products significantly reduced the risk of caries by inhibiting cariogenic bacteria and enriching commensal microbes in the oral cavity. Buffering the salivary pH, production of bacteriocin and enzymes (dextranase, mutanase, and urease), the capacity of competing for the adhesion and colonization on tooth surfaces are the possible mechanisms behind the beneficial effect of probiotics. Further studies are necessary to address the efficacy of long-term probiotic supplementation on the control of dental diseases and the influence of childhood probiotic supplementation on the risk of caries development.

Factors affecting human supragingival biofilm composition. I. Plaque mass.

BACKGROUND AND OBJECTIVE: Little is known about the factors that affect the microbial composition of supragingival biofilms. This study was designed to examine the relationship between total DNA probe counts of supragingival biofilm samples, clinical parameters and supragingival biofilm composition. MATERIAL AND METHODS: Supragingival plaque samples were taken from 187 systemically healthy adult subjects (n = 4745 samples). All samples were individually analyzed for their content of 40 bacterial species using checkerboard DNA-DNA hybridization. The relationship between total DNA probe counts and microbial composition was examined by subsetting the data into 10 groups based on 10 percentile increments of the total DNA probe counts. Differences among groups in terms of species counts and proportions were sought, as well as relationships of total plaque DNA probe count and clinical parameters. RESULTS: There was a wide distribution in mean total DNA probe counts among the 187 subjects. With increasing total plaque levels there was a change in the proportions of individual species and microbial complexes. 'Small plaques' were characterized by high proportions of species in the yellow, orange, purple and 'other' complexes; plaques of moderate mass were characterized by high proportions of Actinomyces and purple complex species, while 'large plaques' exhibited increased proportions of green and orange complex species. Measures of gingival inflammation, pocket depth and recession were significantly positively associated with total DNA probe counts. Increased plaque numbers were related to increased pocket depth irrespective of presence or absence of gingival inflammation. CONCLUSION: The proportions of individual species and microbial complexes in supragingival biofilms are influenced by the total numbers of organisms in the biofilm.

Periodontal debridement as a therapeutic approach for severe chronic periodontitis: a clinical, microbiological and immunological study.

AIM: To clinically, microbiologically and immunologically characterize periodontal debridement as a therapeutic approach for severe chronic periodontitis. MATERIAL AND METHODS: Twenty-five patients presenting at least eight teeth with a probing pocket depth (PPD) of >or=5 mm and bleeding on probing (BOP) were selected and randomly assigned to quadrant-wise scaling and root planing or one session of full-mouth periodontal debridement. The following clinical outcomes were assessed: plaque index, BOP, position of gingival margin, relative attachment level (RAL) and PPD. Real-time PCR was used for quantitative analysis of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia. The enzyme-linked immunosorbent assay permitted the detection of IL-1beta, prostaglandin E(2), INF-gamma and IL-10 in gingival crevicular fluid (GCF). All the parameters were evaluated at baseline, and at 3 and 6 months after treatment. RESULTS: Both the groups had similar means of PPD reduction and attachment gain over time. Besides a significant reduction in the bacterial level after treatment in both groups, microbiological analysis failed to demonstrate significant differences between them. Finally, no difference was observed between groups with respect to the levels of inflammatory mediators in GCF. CONCLUSION: Periodontal debridement resulted in a similar clinical, microbiological and immunological outcome when compared with standard scaling and root planing and therefore may be a viable approach to deal with severe chronic periodontitis.

Microbiota of exposed root surfaces after fluoride, chlorhexidine, and periodontal maintenance therapy: a 3-year evaluation.

BACKGROUND: Fluoride and chlorhexidine (CHX) are state-of-the-art preventive measures for remineralizing teeth and for preventing plaque accumulation. The aim of this study was to examine the effects of fluoride and CHX varnishes on root caries and microbiota located on root surfaces. METHODS: Thirty-three patients from a periodontal maintenance program, having at least one tooth with gingival recession in each quadrant, participated in this study. One tooth per quadrant was assigned randomly to the control group or to one of the test groups that were treated with fluoride varnish, 1% CHX, or 40% CHX. The varnish treatment and the tooth cleaning were repeated every 3 months. Clinical examinations were performed at baseline and once a year for 3 years. Caries status and oral hygiene indices were evaluated clinically. The total cultivable microbiota and percentage of Mutans streptococci (MS), Actinomyces (ACC), and lactobacilli (LB) were analyzed. RESULTS: Oral hygiene was improved greatly during the course of the study. The percentage of MS, ACC, and LB of the total cultivable microbiota revealed a statistically significant reduction between baseline and final examination for each of the four groups. CONCLUSION: Professional tooth cleaning alone at 3-month intervals might be as effective in reducing MS, ACC, and LB as adjunctive treatment with fluoride or chlorhexidine.

Bacterial Biofilm Morphology on a Failing Implant with an Oxidized Surface: A Scanning Electron Microscope Study.

This case report provided a unique opportunity to investigate the extent of microbiota infiltration on the oxidized implant surface that has been compromised by peri-implantitis. Scanning electron microscopic analysis confirmed the etiologic role of the bacteria on the loss of supporting structure and the difficulty in complete removal of bacterial infiltration on the implant surface. This case report emphasizes the need to perform definitive surface decontamination on failing dental implants prior to a regeneration procedure.

Epigenetic Modifications of Histones in Periodontal Disease.

Periodontitis is a chronic infectious disease driven by dysbiosis, an imbalance between commensal bacteria and the host organism. Periodontitis is a leading cause of tooth loss in adults and occurs in about 50% of the US population. In addition to the clinical challenges associated with treating periodontitis, the progression and chronic nature of this disease seriously affect human health. Emerging evidence suggests that periodontitis is associated with mechanisms beyond bacteria-induced protein and tissue degradation. Here, we hypothesize that bacteria are able to induce epigenetic modifications in oral epithelial cells mediated by histone modifications. In this study, we found that dysbiosis in vivo led to epigenetic modifications, including acetylation of histones and downregulation of DNA methyltransferase 1. In addition, in vitro exposure of oral epithelial cells to lipopolysaccharides resulted in histone modifications, activation of transcriptional coactivators, such as p300/CBP, and accumulation of nuclear factor-κB (NF-κB). Given that oral epithelial cells are the first line of defense for the periodontium against bacteria, we also evaluated whether activation of pathogen recognition receptors induced histone modifications. We found that activation of the Toll-like receptors 1, 2, and 4 and the nucleotide-binding oligomerization domain protein 1 induced histone acetylation in oral epithelial cells. Our findings corroborate the emerging concept that epigenetic modifications play a role in the development of periodontitis.

The effects of different levels of dietary sucrose on root caries subsequent to gingivectomy in conventional rats infected with Actinomyces viscosus M-100.

Three groups of weanling, Sprague-Dawley-derived rats were inoculated with Actinomyces viscosus M-100 and fed powdered diet containing either 67%, 5%, or 0% confectioner's sugar. Two further groups were fed diet containing 5% confectioner's sugar and inoculated with Streptococcus sobrinus 6715 or S. sobrinus 6715 plus A. viscosus M-100. The most coronal 1 mm of gingiva was removed from maxillary and mandibular right molar quadrants (gingivectomy), and the animals re-inoculated following gingivectomy. The animals were killed 64 days following gingivectomy, and the lingual surface of mandibular first molar roots was measured for exposed root-surface area and root caries. In the groups of rats infected with A. viscosus M-100, root caries area was significantly greater in the group fed diet containing 67% confectioner's sugar. Sucrose level did not significantly affect the amount of exposed lingual first molar root area regardless of whether the tooth had been subjected to a gingivectomy. In the groups of rats receiving diet containing 5% confectioner's sugar, there were no significant differences in root caries area or exposed root-surface area, regardless of the infection status of the animals. In the rat model presented here, a high level of dietary sucrose was a necessary condition for the initiation of root caries in the absence of other readily fermentable carbohydrates.

A comparison of IgG antibody reactive with Bacteroides forsythus and Porphyromonas gingivalis in adult and early-onset periodontitis.

Recent work has indicated that Bacteroides forsythus and Porphyromonas gingivalis are significant local risk factors for periodontitis. Several reports find that both organisms are frequently associated with periodontitis lesions and often are present together. We have previously shown that early-onset periodontitis patients seropositive for P. gingivalis have less attachment loss than seronegative patients. In this study, we determined serum IgG antibody concentrations reactive with B. forsythus in adult and early-onset periodontitis patients using an ELISA and used P. gingivalis in the same populations as a positive control. The results for P. gingivalis were consistent with previous work and indicated that 47%, 36%, and 33% of adult, generalized early-onset, and localized juvenile patients were seropositive, respectively. Mean serum IgG concentrations for the three groups were 5.36 microg/ml, 5.65 microg/ml, and 5.44 microg/ml for adult, generalized early-onset, and localized juvenile patients, respectively. In contrast, for B. forsythus only 11%, 14%, and 10% of adult, generalized early-onset, and localized juvenile patients were seropositive, with mean serum IgG concentrations of 0.46 microg/ml, 0.46 microg/ml, and 0.47 microg/ml, respectively. This suggests that B. forsythus is either poorly immunogenic or less invasive than P. gingivalis. If most patients fail to mount an immune response to B. forsythus and it is invasive, it may explain why this organism is a risk factor for disease.

Adhesion of Porphyromonas gingivalis strains to cultured epithelial cells from patients with a history of chronic adult periodontitis or from patients less susceptible to periodontitis.

BACKGROUND: The present study aimed to explain the interindividual variation in periodontitis susceptibility by differences in the initial adhesion rate of Porphyromonas gingivalis to the pocket epithelium of these individuals, and/or by inter-P. gingivalis strain differences in association capacity (adhesion and internalization). METHODS: Adhesion assays were performed on epithelial monolayers (cultured in vitro from pocket epithelium belonging to patients who were less or more susceptible to chronic adult periodontitis) using 11 genetically different clinical strains of P. gingivalis. RESULTS: Both the disease category (less susceptible versus susceptible) and the interstrain variation were found to have a significant effect (both P <0.05) on the initial bacterial association. The chronic adult periodontitis group showed significantly more association of P. gingivalis when compared to less susceptible patients (4.2 x 10(6) versus 3.5 x 10(6)). Also, the interstrain variation was significant, with strains Pg 4 and 5 representing the least and best associating bacteria (1.8 x 10(6) colony forming units for Pg 4, 9 x 10(6) for Pg 5). CONCLUSIONS: These results indicate that periodontitis susceptibility is influenced by both the interindividual differences in pocket epithelium (allowing more adhesion of P. gingivalis) or by the strain type by which the patient is infected (intra-species differences in adhesion capacity).

The influence of titanium abutment surface roughness on plaque accumulation and gingivitis: short-term observations.

The roughness of intraoral hard surfaces plays an important role in bacterial adhesion and colonization. Earlier studies have shown that rough surfaces accumulate up to 25 times more subgingival plaque than do smooth sites. In the present study, the influence of surface smoothing was studied. In six partially edentulous patients waiting for a fixed prosthesis supported by endosseous titanium implants, four titanium abutments with different surface roughness were randomly placed. After 1 month of intraoral exposure, subgingival plaque samples from each abutment were compared within each patient by means of differential phase-contrast microscopy. After 3 months, supragingival and subgingival plaque samples were taken from all abutments for differential phase-contrast microscopy and culturing. Probing depth, recession, and bleeding upon probing were scored at the same visit. Differential phase-contrast microscopy showed that subgingivally, only the two roughest abutments harbored spirochetes after 1 month. After 3 months, subgingivally, the composition of the flora showed little variation on the different abutment types, although spirochetes were only noticed around the roughest abutments. Anaerobic culturing resulted in comparable amounts of colony-forming units for all abutment types, both supragingivally and subgingivally. Subgingivally, the microbiologic composition did not show major interabutment differences. Clinically, small differences in probing depth were observed. The roughest abutment showed some attachment gain (0.2 mm) during 3 months, whereas all other abutments had an attachment loss ranging from 0.8 to greater than 1 mm. The results indicate that a reduction in surface roughness (less than a roughness of 0.2 micron) had no major effect on the microbiologic composition, supragingivally or subgingivally. These observations indicate the existence of a threshold roughness below which no further impact on the bacterial adhesion and/or colonization should be expected. However, clinical evaluation seems to indicate that a certain surface roughness is necessary for increased resistance to clinical probing.

GTR treatment of intrabony defects in patients with early-onset and chronic adult periodontitis.

Young, systemically healthy subjects may suffer from early-onset forms of periodontitis characterized by the presence of localized deep vertical bony defects. The aim of this study was to compare the healing response after guided tissue regeneration (GTR) treatment of similar intrabony defects in patients affected by early-onset and chronic adult periodontitis. Twenty systemically healthy, nonsmoking subjects were enrolled in the study; 10 were affected by early-onset periodontitis (EOP) and 10 by chronic adult periodontitis (CAP). In each subject, only one deep vertical bony defect (intrabony component > 4 mm, probing attachment level > or = 8 mm) was treated according to the principles of GTR therapy with titanium-reinforced e-PTFE membranes. At the time of the surgery and at the 1-year follow-up, a microbiologic test for the identification of the main periodontopathogens was performed in each of the treated sites. There was no statistically significant difference at 1 year in the amount of clinical attachment gain (P = .4), reduction of probing pocket depth (P = .3), or increase in gingival recession (P = 1.0) between EOP and CAP patients. The 1-year microbiologic results demonstrated the complete disappearance of the putative periodontopathogens from all surgically treated sites in both patient groups. The results of the study demonstrated that deep intrabony defects in patients with EOP can be successfully treated by means of GTR procedures and that the suppression of periodontopathogens under threshold values can be maintained for at least 1 year, provided that the patient is enrolled in a maintenance program consisting of recalls for professional tooth cleaning and reinforcement of self-performed oral hygiene measures at 1-month intervals.