Receptor activator of NF-kappaB ligand (RANKL) and CD 31 expressions in chronic periodontitis patients before and after surgery.

AIM OF THE STUDY: The present study investigated the hypothesis that upregulation of receptor activator of NF-kappaB ligand (RANKL) expression may be associated with upregulation of endothelial cell activitiy, which is common for periods of periodontal bone loss in chronic periodontitis. MATERIAL AND METHODS: RANKL expression of activated cells in soft tissue biopsies with CD 31 activity and the presence of RANKL and osteoprotegerin (OPG) in gingival crevicular fluid (GCF) were assessed in chronic periodontitis patients. Biopsies from 17 patients and 10 healthy subjects were immunohistochemically analyzed. Clinical measurements [plaque index (PI), the gingival index (GI), probing pocket depth (PPD), clinical attachment level (CAL) and gingival bleeding index (GBI)] and GCF samples were obtained before and after periodontal therapy. RESULTS: CD31 staining did not support the assumption that endothelium-like cells were predominantly associated with RANKL expression. CONCLUSIONS: RANKL-positive cells were widely distributed in periodontitis patients giving only partial support to the hypothesis that RANKL expression is restricted to T- and B-cell activation.

Ridge augmentation and maxillary sinus grafting with a biphasic calcium phosphate: histologic and histomorphometric observations.

OBJECTIVES: This retrospective study reports on histologic and histomorphometric observations performed on human biopsies harvested from sites augmented exclusively by biphasic calcium phosphate [BCP: hydroxyapatite (HA)/ tricalcium phosphate (TCP) 60/40] and healed for a minimum of 6 months. MATERIALS AND METHODS: Five patients benefited from three augmentation regimens (i.e.: one-stage lateral augmentation; two-stage lateral augmentation; and two-stage sinus grafting). In all patients, a degradable collagen membrane served as a cell-occlusive barrier. Core biopsies were obtained from lateral as from crestal aspects 6-10 months after augmentation surgeries. For histologic and histomorphometric evaluations, the non-decalcified tissue processing was performed. RESULTS: The histological examination of 11 biopsies showed graft particles frequently being bridged by the new bone, and a close contact between the graft particles and newly formed bone was seen in all samples. The mean percentages of newly formed bone, soft tissue compartment, and graft material were 38.8% (+/-5.89%), 41.75% (+/-6.08%), and 19.63% (+/-4.85%), respectively. Regarding bone-to-graft contact values, the percentage of bone coverage of graft particles for all biopsies ranged from 27.83% to 80.17%. The mean percentage of bone coverage was 55.39% (+/-13.03%). CONCLUSIONS: Data from the present study demonstrated osteoconductivity scores for the BCP material (HA/TCP 60/40) in patients resembling those previously shown for grafting materials of xenogenic and alloplastic origin.

Are putative periodontal pathogens reliable diagnostic markers?

Periodontitis is one of the most common chronic inflammatory diseases. A number of putative bacterial pathogens have been associated with the disease and are used as diagnostic markers. In the present study, we compared the prevalence of oral bacterial species in the subgingival biofilm of generalized aggressive periodontitis (GAP) (n = 44) and chronic periodontitis (CP) (n = 46) patients with that of a periodontitis-resistant control group (PR) (n = 21). The control group consisted of subjects at least 65 years of age with only minimal or no periodontitis and no history of periodontal treatment. A total of 555 samples from 111 subjects were included in this study. The samples were analyzed by PCR of 16S rRNA gene fragments and subsequent dot blot hybridization using oligonucleotide probes specific for Aggregatibacter (Actinobacillus) actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, a Treponema denticola-like phylogroup (Treponema phylogroup II), Treponema lecithinolyticum, Campylobacter rectus, Fusobacterium spp., and Fusobacterium nucleatum, as well as Capnocytophaga ochracea. Our data confirm a high prevalence of the putative periodontal pathogens P. gingivalis, P. intermedia, and T. forsythia in the periodontitis groups. However, these species were also frequently detected in the PR group. For most of the species tested, the prevalence was more associated with increased probing depth than with the subject group. T. lecithinolyticum was the only periodontopathogenic species showing significant differences both between GAP and CP patients and between GAP patients and PR subjects. C. ochracea was associated with the PR subjects, regardless of the probing depth. These results indicate that T. lecithinolyticum may be a diagnostic marker for GAP and C. ochracea for periodontal health. They also suggest that current presumptions of the association of specific bacteria with periodontal health and disease require further evaluation.

Minimally invasive flap surgery and enamel matrix derivative in the treatment of localized aggressive periodontitis: case report.

Localized aggressive periodontitis is a distinct entity of periodontal disease and is characterized by deep vertical bony defects that typically affect the first molars and incisors of young patients. Therapy is usually aimed at reducing the pathogenic microflora through scaling and root planing and the administration of systemic antibiotics. However, conservative periodontal therapy may result in reparative wound healing with limited regeneration of the lost tissues. Periodontal surgery combined with enamel matrix derivative has been introduced as a method to promote regeneration of the lost periodontium and has been studied extensively in the treatment of chronic periodontitis. This case report describes the treatment of a 27-year-old patient displaying severe localized aggressive periodontitis with documented disease progression. After initial therapy consisting of scaling and root planing and systemic administration of amoxicillin and metronidazole, the vertical defects were treated by minimally invasive access flaps combined with application of enamel matrix derivative. Clinical, microbiologic, and radiographic findings are reported for up to 1.5 years after initial therapy, indicating good efficacy of the therapeutic strategy and stability of the treatment outcome.

Stimulation of osteoblasts with Emdogain increases the expression of specific mineralization markers.

OBJECTIVE: The purpose of this study was to determine the effects of enamel matrix derivative on mRNA expression of markers related to periodontal healing. STUDY DESIGN: Murine osteoprogenitor cells (MC3T3-E1) were grown for 12 and 16 days in mineralization media and stimulated with 100 microg/mL Emdogain (EMD). Cell cultures treated with 2% and 10% fetal calf serum (FCS) served as control. The mRNA expression of bone sialoprotein (BSP), osteopontin (OPN), and runt-related protein 2 (Runx2) was analyzed by real-time polymerase chain reaction. One-way analysis of variance was used for statistical analysis. RESULTS: Stimulation with EMD significantly (P < .01) enhanced mRNA expression of BSP up to 13.9-fold and of OPN up to 3.2-fold at day 16 compared with the 2% FCS control. The expression of mRNA for transcription factor Runx2 was not significantly changed. CONCLUSION: The beneficial effects seen in periodontal regeneration after treatment with EMD may be related to an increase of the mineralization markers BSP and OPN at mRNA level.

Cytobiocompatibility of collagen and ePTFE membranes on osteoblast-like cells in vitro.

In guided bone regeneration (GBR), a semipermeable membrane is placed over an osseous defect to create a secluded environment in which bone formation can proceed without ingrowth of connective tissue cells from the overlaying soft tissue. Although the cell-occlusive property of GBR membranes appear to be essential to new bone formation, the role of transmembrane tissue fluid diffusion is not known. The objective of this study was to evaluate the degree to which diffusion across commonly used GBR membranes can support functional properties of osteoblast-like cells in vitro. Cells from an established osteoblast-like line (SAOS-2) were cultured on membranes of cross-linked collagen, noncross linked collagen, and ePTFE. The membranes rested on metal grids which allowed the membranes to lightly contact the surface of the culture medium. As a control, cells were directly plated and cultured in control wells. At days 7 and 21, cells were harvested by scraping the membranes or culture wells and analyzed for expression of alkaline phosphatase (ALP), core binding factor 1 (cbfa-1), bone sialoprotein-2 (BSP-2), and osteocalcin (OC). Expression was determined by quantitative real-time PCR. Glucose-6-phosphate dehydrogenase (G6PD) served as a reference gene. The membranes were examined by transmission light microscopy. RT-PCR revealed up-regulation of ALP of up to 60-fold and of cbfa-1 and BSP of up to threefold relative to G6PDH. Expression of OC was less then onefold. The expression profile for each of the four genes tested demonstrated small variations among cells grown on different membranes. Microscopic observations revealed remnants of undisrupted osteoblast-like cells attached to both collagen membranes. Cell morphology and spatial arrangement indicated that vitality was maintained. Diffusion through the three membranes evaluated in this study was sufficient to support osteoblast-like cell differentiation.

Enamel matrix derivative induces connective tissue growth factor expression in human osteoblastic cells.

BACKGROUND: Enamel matrix derivative (EMD) stimulates the production of transforming growth factor-beta (TGF-beta), which has been suggested to play a role in mediating the effects of EMD in periodontal tissue regeneration. Connective tissue growth factor (CTGF) is a mediator of TGF-beta and promotes cell development. The interaction between EMD and CTGF is unknown. This study explored the effects of EMD on CTGF expression in human osteoblastic cells and whether the interaction is modulated by the TGF-beta signaling pathway. Also, the roles of CTGF in cell proliferation, cell cycle progression, and mineralized nodule formation of EMD-induced osteoblastic cultures were examined. METHODS: Human osteoblastic cells (Saos-2) were treated with 25 to 100 microg/ml EMD with or without the addition of TGF-beta inhibitor. CTGF mRNA expression was detected by reverse transcription-polymerase chain reaction (RT-PCR), and CTGF protein levels were assayed by Western blot analysis. In addition, cell cycle progression and DNA synthesis were determined by flow cytometry and 5-bromo-2'-deoxyuridine (BrdU) incorporation following EMD treatment with or without CTGF antibody. Mineralization was examined by alizarin red staining and quantified by elution with cetylpyridinium chloride. RESULTS: Western blot and RT-PCR analysis demonstrated a dose-dependent increase of CTGF expression by EMD. EMD-induced CTGF expression was reduced significantly in the presence of TGF-beta inhibitor. Cell cycle and BrdU analysis revealed an increase in cell proliferation following EMD treatment, which was due to an increase in the percentage of cells in the G2/M phase of the cell cycle. No significant effect was found when anti-CTGF antibody was added. Conversely, mineralization was inhibited significantly in EMD-treated cultures in the presence of anti-CTGF antibody. CONCLUSIONS: EMD stimulates CTGF expression, and the interaction is modulated via TGF-beta in osteoblastic cells. Also, CTGF affects EMD-induced osteoblastic mineralization but not cell proliferation. To our knowledge, these results provide novel insight into EMD-CTGF interaction, two biomodifiers that have therapeutic relevance to tissue engineering and regeneration.

Controlled-delivery chlorhexidine chip versus amoxicillin/metronidazole as adjunctive antimicrobial therapy for generalized aggressive periodontitis: a randomized controlled clinical trial.

BACKGROUND: Subgingival application of chlorhexidine via a controlled-delivery device (CHX chip) improves the clinical outcome of scaling/root planing (SRP) in therapy for chronic periodontitis. Generalized aggressive periodontitis (GAP) is commonly treated with SRP and adjunctive antimicrobial medication. To date, the efficacy of CHX chips in GAP therapy has not been evaluated. AIM: To compare SRP plus adjunctive CHX chip placement with SRP plus adjunctive systemic amoxicillin/metronidazole with regard to clinical efficacy in first-line therapy for GAP. MATERIAL AND METHODS: Thirty-six GAP patients were treated with SRP and randomly with either placement of CHX chips or systemic amoxicillin/metronidazole. Clinical attachment level (CAL), probing depth (PD), bleeding on probing (BoP) and suppuration (Pus) were measured at baseline, 3 and 6 months after therapy. RESULTS: CAL, PD, BoP and Pus were significantly reduced in both groups after 3 months. In the CHX chip group, PD significantly increased again between 3 and 6 months. Finally, amoxicillin/metronidazole patients presented significantly more CAL "gain", PD reduction and less remaining deep sites after 6 months. Pus remained detectable in CHX chip patients only. CONCLUSIONS: In first-line non-surgical therapy for GAP, SRP plus adjunctive systemic amoxicillin/metronidazole was more efficacious in clinically relevant measures of outcome than SRP plus adjunctive placement of CHX chips.

Timing affects the clinical outcome of adjunctive systemic antibiotic therapy for generalized aggressive periodontitis.

BACKGROUND: Systemic antibiotics improve the outcome of scaling and root planing (SRP) in patients exhibiting severe periodontitis. This study evaluated the influence of timing of adjunctive systemic antibiotics in the sequence of periodontal therapy. METHODS: Two cohorts of patients with generalized aggressive periodontitis and treated by SRP, adjunctive antibiotics, and supportive periodontal therapy (SPT) were analyzed retrospectively. Cohort A (17 patients; 36 +/- 5 years of age) received systemic amoxicillin/metronidazole immediately after SRP ("immediate"); cohort B (17 patients; 36 +/- 4 years of age) received the same regimen 3 months after SRP, following SPT, including subgingival reinstrumentation ("late"). Clinical parameters, including probing depth (PD), relative attachment level (RAL), bleeding on probing (BOP), and suppuration, were recorded with a pressure-sensitive electronic probe at baseline and 3 and 6 months after SRP. RESULTS: Significant time*group interactions were found for all clinical parameters except BOP, i.e., timing of antibiotic therapy affected the course of clinical changes over time. Immediate antibiotic therapy produced significantly higher initial changes (0 to 3 months) in PD and RAL. Late antibiotic therapy at 3 months resulted in additional significant improvements in all clinical parameters between 3 and 6 months. In initially deep sites (baseline PD >6 mm), improvements in PD and RAL over 6 months were significantly higher with immediate antibiotic therapy compared to late antibiotic therapy. CONCLUSION: Within the limits of a retrospective analysis, these findings indicate that administration of amoxicillin/metronidazole immediately after initial SRP provides more PD reduction and RAL "gain" in initially deep sites than late administration at SPT with reinstrumentation after 3 months.

Influence of periodontal therapy on the regulation of soluble cell adhesion molecule expression in aggressive periodontitis patients.

BACKGROUND: Inflammatory periodontal disease is associated with an increased risk of cardiovascular disease. Circulating cell adhesion molecules (CAM) (intercellular adhesion molecule-1 [ICAM-1], vascular cell adhesion molecule-1 [VCAM-1], and E-selectin) have been suggested as potential candidate markers of endothelial dysfunction, which contribute to the pathogenesis of cardiovascular diseases. The regulation of CAM in subjects with severe periodontitis and the influence of periodontal intervention on systemic CAM levels are not clear. The aim of this study was to determine whether intensive periodontal therapy reduces serum levels of CAM in patients with generalized aggressive periodontitis. METHODS: Blood samples were collected at six treatment time points from 21 patients with previously untreated generalized aggressive periodontitis (mean age: 34.6 +/- 4.3 years). Patients received subgingival scaling and root planing and antibiotic therapy and were monitored over a 6-month recall period. Serum levels of soluble ICAM-1 (sICAM-1), VCAM-1 (sVCAM-1), and E-selectin (sE-selectin) were measured by enzyme-linked immunosorbent assay. RESULTS: sE-selectin plasma levels decreased significantly (P <0.01) during periodontal therapy. Mean plasma levels were 65.95 ng/ml before treatment and 44.71 ng/ml 6 months after antibiotic therapy. sICAM-1 and sVCAM-2 serum levels were unaffected by therapeutic intervention. CONCLUSIONS: Periodontal therapy reduces plasma sE-selectin levels. Whether this leads to a reduction in risk of future cardiovascular events in patients with aggressive periodontal disease warrants further studies.

Amelogenin expression in long bone and cartilage cells and in bone marrow progenitor cells.

The amelogenin protein is considered as the major molecular marker of developing ectodermal enamel. Recent data suggest other roles for amelogenin beyond structural regulation of enamel mineral crystal growth. Here we describe our novel discovery of amelogenin expression in long bone cells, in cartilage cells, in cells of the epiphyseal growth plate, and in bone marrow stromal cells.

Calprotectin and cross-linked N-terminal telopeptides in peri-implant and gingival crevicular fluid.

In a previous study on guided bone augmentation, a new collagen membrane was compared with an e-PTFE one on 28 partially edentulous patients who received 50 dental implants at stage 2 surgery. After implant integration and subsequent loading, we were able to recruit 22 patients with 22 implants and their contra-lateral corresponding teeth for longitudinal observation. Clinical parameters probing depth (PD), bleeding on probing (BoP), plaque index (PI), assessment of gingival crevicular fluid (GCF) and peri-implant crevicular fluid (PCF) volumes and periapical radiographs were performed at 2- and 3-year control appointments. Calprotectin (MRP 8/14) and cross-linked N-terminal telopeptide (NTx) levels in both crevicular fluids were determined by ELISA. PD was significantly reduced from years 2 to 3 appointments at implant sites as at teeth sites. At the 3-year appointment in both compartments, fluid volumes were significantly increased, which corresponded well with ascending NTx levels. The total amount of calprotectin decreased non-significantly in both GCF and PCF samples. Periapical radiographs revealed stable bone conditions around implants without significant changes from years 2 to 3 examinations. Clinical peri-implant parameters were considered as stable as the periodontal parameters of their corresponding teeth. A parallel increase in NTx levels in both GCF and PCF at 3-year appointment is not clearly understood; it may reflect an upregulation in the overall bone turnover rate.

Effects of an enamel matrix derivative on human osteoblasts and PDL cells grown in organoid cultures.

OBJECTIVE: The objective of this study was to investigate cellular effects of enamel matrix derivative (EMD) in human derived, primary osteoblasts and periodontal ligament (PDL) cells grown in organoid cultures. STUDY DESIGN: Cell replication was assessed by BrdU-incorporation. [(3)H]-proline incorporation was measured to determine the synthesis of proline-containing proteins, such as collagen. In addition, calcium accumulation and alkaline-phosphatase-activity were quantified. Electron microscopy for morphological analysis was performed. RESULTS: Our results showed that EMD enhances BrdU-incorporation in PDL cells and osteoblasts. Also, in osteoblast organoid cultures [3H]-proline incorporation was 3-fold increased (P < .01). Extensive matrix deposition was noted in osteoblast cultures by electron microscopy. In osteoblasts, high levels of calcium accumulation and alkaline-phosphatase-activity were found. However, EMD did not promote mineralization. CONCLUSION: Our results indicate that under organoid culture conditions EMD is able to promote the synthesis of proline-containing proteins such as collagen but not matrix mineralization of primary human osteoblastic cells.

In vitro attachment of osteoblasts on contaminated rough titanium surfaces treated by Er:YAG laser.

Microbial contamination of implant surfaces inhibits formation of new osseous tissues. Biocompatibility of sandblasted large grid (SLA) surface, after previous in vitro cocultivation with Porphyromonas gingivalis and concomitant Er:YAG laser irradiation of microorganisms, was tested by attachment of newly cultured osteoblasts. A total of 36 customized titanium cubes with SLA surface were placed into human osteoblast culture for 14 days. After removal of 1 control cube, 35 other cubes were contaminated with precultured P. gingivalis (ATCC33277) and incubated in broth medium for 1 week. Ablation was carried out on 32 cubes. Each side was treated for 23.5 s with a pulsed, water-cooled laser beam. After irradiation, cubes were again placed into fresh osteoblast culture for 2 weeks. One randomly selected single side per cube was analyzed by scanning electron microscope in 22 cubes. On other 10 cubes, vitality of attached cells was tested with ethidiumbromide staining by fluorescence microscopy. Three negative controls revealed constantly adherent P. gingivalis, and no osteoblasts were detectable after P. gingivalis contamination on the surfaces. Laser-treated specimens showed newly attached osteoblasts, extending over 50-80% of the surface. Positive control cube (without bacterial contamination) showed over 80% cell coverage of the surface. Vitality of widely stretched osteoblasts was confirmed by FITC staining. Our results indicate that Er:YAG laser was effective in removing P. gingivalis and cell compounds, offering an acceptable surface for new osteoblast attachment.

Amelogenin, a major structural protein in mineralizing enamel, is also expressed in soft tissues: brain and cells of the hematopoietic system.

The amelogenin protein is considered as the major molecular marker of developing and mineralizing ectodermal enamel. It regulates the shape, size, and direction of growth of the enamel mineral crystallite. Recent data suggest other roles for amelogenin beyond regulation of enamel mineral crystal growth. The present study describes our recent discovery of amelogenin expression in soft tissues: in brain and in cells of the hematopoietic system, such as macrophages, megakaryocytes and in some of the hematopoietic stem cells. Reverse transcription-polymerase chain reaction (RT-PCR) followed by cDNA sequencing revealed, in mouse brain, two amelogenin mRNA isoforms: the full-length amelogenin including exon 4, and the isoform lacking exon 4. Immunohistochemistry revealed amelogenin expression in brain glial cells. Mouse macrophages were found to express the full-length amelogenin sequence lacking exon 4. Confocal microscopy revealed colocalization of amelogenin and CD41 (a megakaryocyte marker), as well as amelogenin and CD34 (a hematopoietic stem cell marker) in some of the bone marrow cells. The expression of amelogenin, a major structural protein of the mineralizing extracellular enamel matrix, also in cells of non-mineralizing soft tissues, suggests that amelogenin is multifunctional. Several different potential functions of amelogenin are discussed.

Gingival crevicular fluid levels of calprotectin and myeloperoxidase during therapy for generalized aggressive periodontitis.

BACKGROUND: Levels of the inflammation marker calprotectin in gingival crevicular fluid correspond to clinical and biochemical parameters of periodontal inflammation. Neutrophil granulocytes (polymorphonuclear neutrophils: PMNs) are supposed to be the main source of calprotectin in gingival crevicular fluid, but evidence is still lacking. The influence of periodontal therapy on gingival crevicular fluid levels of calprotectin has not yet been determined. OBJECTIVES: Gingival crevicular fluid levels of calprotectin were monitored during therapy for generalized aggressive periodontitis. Interrelations between calprotectin and the PMN marker myeloperoxidase (MPO) were evaluated. MATERIAL AND METHODS: Gingival crevicular fluid samples were collected from 23 patients with generalized aggressive periodontitis before and 3 months after non-surgical therapy with an adjunctive antimicrobial medication. Clinical parameters were recorded with a pressure-calibrated electronic probe. Levels of calprotectin and MPO in gingival crevicular fluid were analysed by enzyme-linked immunosorbent assay (ELISA) procedures. RESULTS: At baseline, levels of calprotectin and MPO were highly correlated. Bleeding and suppurating sites showed significantly higher levels of calprotectin and MPO than non-bleeding, non-suppurating sites. Therapy significantly decreased levels of both biomarkers. These changes of calprotectin and MPO were highly correlated and also related to probing-depth reduction. Three months after therapy, the levels of both markers still showed significant correlations in initially deep sites, whereas in initially shallow sites no significant correlation was found. After therapy, levels of markers in bleeding and non-bleeding sites were comparable. CONCLUSION: The correlations between calprotectin and MPO indicate that PMNs are a major contributor to the calprotectin content in gingival crevicular fluid of severely affected sites. Calprotectin levels in gingival crevicular fluid and their changes reflect periodontal inflammation as well as the clinical treatment outcome. A prognostic potential of this marker substance remains to be determined.

Moderate effect of enamel matrix derivative (Emdogain Gel) on Porphyromonas gingivalis growth in vitro.

OBJECTIVE: The aim of this study was to analyse the antibacterial effects of Emdogain Gel or its constituents on the growth of the suspected periodontopathogen Porphyromonas gingivalis. STUDY DESIGN: The effects of the proteins of enamel matrix derivative (EMD), the commercial product Emdogain Gel or its vehicle propylene glycol alginate (PGA) (Straumann, Switzerland) on P. gingivalis growth were determined by two methods: broth dilution assay (BDA) and agar diffusion assay (ADA). RESULTS: BDA-Emdogain Gel inhibited moderately the growth of P. gingivalis, whereas EMD showed no effect. The PGA vehicle inhibited the growth completely. ADA-Emdogain Gel resulted in some inhibition in growth but was not significantly different from control. EMD revealed no zone of inhibition. PGA demonstrated statistically significant zones of inhibition. CONCLUSION: Emdogain Gel shows moderate antibacterial activities against P. gingivalis. These properties seem to be due to the PGA component of the gel preparation.

Coverage of Miller class I and II recession defects using enamel matrix proteins versus coronally advanced flap technique: a 2-year report.

BACKGROUND: The aim of this study was to evaluate a comparison of the coronally advanced flap procedure with or without the use of enamel matrix proteins in the treatment of recession defects. METHODS: This 2-year study was conducted as a blinded, split-mouth, placebo-controlled, and randomized design. Thirty patients from two dental schools with two paired buccal recession defects were chosen. Surgical recession coverage was performed as the coronally advanced flap technique. One site was additionally treated with derivative (EMD) and the other site with a placebo (propylene glycol alginate [PGA]). A blinded examiner assessed pre- and post-surgical measurements. Measurements comprised the height and width of the gingival recession, height of keratinized tissue, probing attachment level, probing depth, and alveolar bone level. RESULTS: Twenty-four months after therapy, both treatment modalities showed significant root coverage and probing attachment gain. The mean gingival recession decreased from 3.6 to 0.8 mm for the EMD-treated sites and from 3.8 to 1.4 mm for the control sites. However, this difference was not statistically significant (P = 0.122). Similarly, all other clinical parameters did not differ significantly in the between-group comparison except for the recession width (P = 0.027) and probing depth (P = 0.046) exhibiting higher reductions in the EMD group. Complete root coverage could be maintained over 2 years in 53% of the EMD versus merely 23% in the control group. A total of 47% of the treated recessions in the control group deteriorated again in the second year after therapy compared to 22% in the EMD group. CONCLUSION: Enamel matrix derivative seems to provide better long-term results.

Immediate substitution of central incisors with an unusual enamel paraplasia by a newly developed titanium implant: a case report.

The replacement of incisors with an unfavorable hard and soft tissue environment in the maxilla can be a challenging procedure in terms of esthetic outcome. The present report describes the replacement of two hopeless central incisors by newly developed titanium implants (TE Implant, Straumann) for immediate placement. This type of implant was chosen to compensate for the natural esthetics, which became compromised because of periodontitis and an unusual root anatomy. Both incisors presented with an atypical enamel paraplasia characterized by a circumferential enamel projection in apical direction. The consequence was a markedly reduced surface for periodontal attachment. Two weeks after implant placement, two acrylic resin crowns were cemented onto the new temporary titanium abutments. Five months later, the definitive prosthetic restoration was processed by porcelain pressed onto galvanic-cap crowns, which were cemented to standard wide-neck abutments. Control radiographs showed uneventful healing.

[Critical assessment of microbiological diagnostics in periodontal diseases with special focus on Porphyromonas gingivalis]. / Kritische Beurteilung mikrobiologischer Diagnostik bei marginaler Parodontitis unter besonderer Berüchsichtigung von Porphyomonas gingivalis.

Periodontitis is caused by an opportunistic infection with pathogenic microorganisms of the oral biofilm. In this paper, we discuss the usefulness of microbial diagnostics with respect to the differential diagnosis or the treatment approaches of periodontal diseases. Several diagnostic techniques, based on morphological, enzymatic, cultural, genetic or antigenetic properties have been established to analyze the microbial flora. Among the bacterial species some virulent genotypes of P. gingivalis play an important role in the etiology of periodontitis. Expression of fimbriae or different proteases have been identified as potential virulence factors of this gram negative anaerobic rod. To date a characterization of virulence of specific strains or a correlation between expression of different virulence factors and distinct periodontal conditions, however, is missing. Therefore, the importance of a routine identification of P. gingivalis still needs further evaluation.