Search Results - (Author, Cooperation:N. Zitzmann)

2014-01-05

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Antibodies, Monoclonal/chemistry ; Antiviral Agents/chemistry ; Cancer Vaccines/chemistry ; *Drug Design ; Glycolipids/*chemistry/metabolism/*therapeutic use ; Glycoproteins/*chemistry/metabolism/*therapeutic use ; Glycosylation ; HIV Infections/drug therapy ; Humans ; Metabolic Diseases/drug therapy/metabolism ; Neoplasms/drug therapy ; *Polysaccharides/biosynthesis/chemistry/classification ; Viral Vaccines/chemistry

1600-051X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Objectives: The purpose of this study was to examine reactions of gingiva and peri-implant mucosa (PiM) to de novo plaque accumulation in humans.Material and Methods: Prior to the start of the study, which included 12 partially edentulous subjects, a 3-week plaque control program was performed. Ethical approval was granted by the local ethics committee. On day 0, 2 soft tissue biopsies were harvested, 1 from a tooth and 1 from an implant site in every subject. After 3 weeks of undisturbed plaque accumulation (day 21), 2 additional biopsies were obtained from the gingiva and PiM in each subject. The tissue samples, each 4×4 mm in size, were snap frozen and prepared for immunohistochemical analysis.Results: The size of the infiltrate (ICT) in the day 0 biopsies, was about 0.03 mm2 in both the gingiva and PiM. At the end of the plaque accumulation period, the size of the lesion had significantly increased in both groups and occupied an area of 0.26 mm2 in the gingiva and 0.14 mm2 in PiM. In the biopsies presenting day 0, the proportions of the various cell populations examined were similar in the gingiva and in PiM. The tissue fractions of almost all types of cells increased during the 3 weeks, but the mean change for each cell type was greater in the gingiva than in PiM. The CD3/CD19 ratio decreased in the gingiva between day 0 and 21, but increased in PiM.Conclusion: The results of the present study indicated that plaque accumulation induced an inflammatory response characterized by increased proportions of T- and B-cells in the ICT of both the gingiva and the PiM. Although not statistically significant, the host response in the gingiva tended to be more pronounced than in the peri-implant mucosa.

Electronic Resource

1600-051X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background: The host response to microbial challenge depends on the recruitment of homing leucocytes and may be related to the experience to infectious insults over years.Purpose: The aim of this study was to investigate the soft tissue reactions to de novo plaque formation at sites treated with either open flap debridement or with the use of resective means during periodontal therapy.Material and Methods: Fifteen patients, who had been treated for periodontal disease (severe generalized chronic periodontitis), participated in the study. Surgical therapy was performed using either gingivectomy (GV) or open flap debridement (OFD) procedures in a split mouth design. After 6 months of healing (day 0), two gingival biopsies were obtained, one from the GV- and one from the OFD-treated sites. The experimental gingivitis model was applied and plaque accumulation was allowed for 3 weeks. New biopsies were obtained from the remaining quadrants on day 21 of plaque formation. The biopsies were snap frozen and prepared for immunohistochemical analysis.Results: Following 3 weeks of plaque accumulation, the size of the lesion in OFD sites was more than twice as large than that in GV sites (0.42 versus 0.19 mm2). In the GV units, the lesion was characterized by almost similar proportions of T cells (CD3+, 6.0%) and B cells (CD19+, 6.6%), while the ICT in OFD sites was dominated by B cells (13.8%). During the 3-week period of plaque formation the increase in cell densities of T and B cells was three times larger in OFD than in GV sites. The proportion of ELAM-1 (CD62+ cells) decreased in GV (−0.4%) and increased in OFD (0.9%) sites.Conclusions: The host response that occurred in the gingival sites treated with OFD was more pronounced than the reaction that under similar experimental conditions took place in the regenerated gingiva at sites treated by resective means.

Electronic Resource

1600-051X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background: Findings from previous experiments have revealed that inflammatory cell infiltrates may remain in the gingiva following clinically successful non-surgical periodontal therapy.Purpose: To investigate the presence of inflammatory lesions in the gingiva following a periodontal treatment procedure that included either soft-tissue resection [gingivectomy (GV)] or non-resective open-flap debridement (OFD).Material and Methods: Fifteen patients with advanced generalized chronic periodontitis were recruited. Following oral hygiene instruction and supragingival debridement, one tooth site in each quadrant (non-molar, probing pocket depth〉5 mm, bleeding on probing+ and 〉50% bone loss) was selected and a soft-tissue biopsy was obtained and prepared for immunohistochemical analysis. Using a split-mouth design, two quadrants were randomly selected for periodontal therapy including GV, while the two remaining quadrants were exposed to non-resective OFD procedure. Six months after completion of surgical treatment, a new set of biopsies was obtained from GV and OFD sites.Results: The inflammatory lesions residing in the gingival biopsies obtained prior to surgical therapy were 1.33–1.41 mm2 large and contained similar proportions of CD19+- (B-cells, 15%), CD3+- (T-cells, 7%) and elastase+- (polymorphonuclear cells, 2%) cells in the two treatment groups. The corresponding lesions identified in the soft-tissue specimens obtained after 6 months of healing were twice as large at OFD as at GV sites (0.19 versus 0.08 mm2, p=0.002). The densities of CD19+- and elastase+-cells in these lesions were significantly greater at OFD than at GV sites.Conclusion: The findings of the present study indicate that surgical therapy including soft-tissue resection results in regenerated gingival units that contain smaller lesions with lower densities of immunocompetent cells when compared with the lesions remaining in sites treated by non-resective means.

Electronic Resource

1600-051X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Objectives: The purpose of this study was to analyze the expression of adhesion molecules on endothelial cells in the alveolar ridge mucosa, the gingiva and the periimplant mucosa in humans.Material and methods: Twelve partially edentulous subjects were included in the study. In each subject, one soft tissue biopsy was harvested from the edentulous alveolar ridge mucosa, one from a tooth site and one from an implant site. After 3 weeks of undisturbed plaque accumulation, an additional biopsy was obtained from one tooth and one implant site in each subject. The tissue samples were snap frozen and prepared for immunohistochemical analysis.Results: In the alveolar ridge mucosa, smaller proportions of endothelial cells expressing ICAM-1, ELAM-1 and VCAM-1 were observed than in the gingiva. ELAM-1-positive cells occurred in lower numbers than in periimplant mucosa. After 21 days of plaque accumulation, ELAM-1 was increased in tooth sites, but decreased in periimplant mucosa.Conclusion: The results of the present study indicated that the proportions of activated endothelial cells and the extravasation of leukocytes is larger in gingiva and periimplant mucosa than in alveolar ridge mucosa. This might be due to the less permeable keratinized epithelial layer in the edentulous ridge mucosa, which offers proper protection against microbial pathogens. The greater expression of endothelial cell adhesion molecules during experimental gingivitis, compared to periimplant mucositis, may reflect its longer history of repeated antigenic assaults.

Electronic Resource

1600-051X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background: Periimplantitis represents an inflammatory condition that is associated with the presence of a submarginal biofilm and with advanced breakdown of soft and mineralized tissues surrounding endosseous implants. Animal models have been used to describe mechanisms involved in the pathogenesis and treatment of the soft and hard tissue lesions of periimplantitis.Objective: The aim of the present experiment was to study the presence and progression of inflammatory lesions in tissues surrounding implants exposed to “experimental periimplantitis”.Material and Methods: Five Labrador dogs were used. In each dog, 2 or 3 implants were placed in both the left and right edentulous premolar regions of the mandible. Abutment connection was performed 4 months later and a plaque control regimen was initiated and maintained for 5 months. “Experimental periimplantitis” was subsequently induced by ligature placement and plaque accumulation was allowed to progress until about 40% of the height of the supporting bone had been lost. The ligatures were removed, but plaque formation was allowed to continue for an additional 12 months. Radiographs of all implant sites were obtained before and after active “experimental periimplantitis” as well as at the end of the experiment. Biopsies were harvested from the implant sites in 3 of the dogs. The tissue samples were prepared for light microscopy and the sections were used for histometric and morphometric examinations.Results: One implant was lost during the first 2 months of “experimental periimplantitis” and two implants were lost during the 12 months that followed ligature removal. The radiographic examination indicated that varying amounts of additional bone loss occurred in the majority of the implant sites also following ligature removal. The mucosa of all implant sites harbored inflammatory lesions that extended apically of the pocket epithelium. The lesions were separated from the marginal bone by a zone of apparently normal connective tissue.Conclusion: A remission of the destructive inflammatory lesion in the periimplant tissues was seen in some sites following ligature removal, but in the majority of sites additional loss of supporting bone occurred.

Electronic Resource

1600-051X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background: Findings from in vitro studies have indicated that the orientation and proliferation of cells on titanium surfaces may be influenced by the topography of the surface on which they are grown. It may be argued, therefore, that differences may occur in the mucosal attachment to titanium implants with different surface roughness.Aim: The present experiment was performed to study the composition of the soft tissue barrier that formed to implants prepared with well-defined smooth or rough surfaces.Material and Methods: Five beagle dogs were used. Four implants made of c.p. titanium were placed in the right edentulous mandibular premolar region. After 3 months, two different types of abutments were connected: one experimental (OA) with a dual, thermal acid-etched surface (‘Osseotite®’), and one regular (RA) abutment with a ‘turned’ surface. At the end of a 6-month period during which proper plaque control had been maintained, biopsies including the implant and the surrounding soft and hard tissues were obtained, decalcified and processed for light and electron microscopy. A confocal He–Ne laser profilometer was used to study the surface topography of the abutments.Results: The attachment between the peri-implant mucosa and titanium abutments with either a turned (RA; ‘smooth’) or acid-etched (OA; ‘rough’) surface was similar from both a quantitative and a qualitative aspect. The attachment comprised a barrier epithelium and a zone of connective tissue attachment of similar dimension at RA and OA. It was further observed that the ‘inner’ zone of the connective tissue attachment at both types of abutment was composed of about 30–33% fibroblasts and 63–66% collagen.Conclusion: It was demonstrated that the soft tissue attachment that formed to implants made of c.p. titanium was not influenced by the roughness of the titanium surface.

Electronic Resource

1600-051X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background: The mucosal attachment that forms to titanium implants, uncontaminated by bacterial plaque comprises, independent of the surface characteristics of the abutment, one barrier epithelium and one zone of connective tissue attachment. It was suggested that abutments with a rough surface may accumulate more plaque than abutments with a smooth surface and that such an enhanced rate of plaque build-up may favor the development of inflammatory lesions in the periimplant mucosa.Objectives: The aim of the present experiment was to study some reactions of the periimplant mucosa to plaque accumulation on implant abutments designed with either a rough or a smooth external surface.Material and Methods: In five beagle dogs, four fixtures were placed and submerged in the premolar region. In a second stage procedure performed after 3 months, abutments with two different types of surface topography, one rough, acid-etched (OA) and one smooth, turned abutment (TA), were installed in a random order. After 6 months of undisturbed plaque formation, the animals were sacrificed and biopsies obtained. Tissue samples were prepared for light microscopy and exposed to histometric and morphometric measurements.Results: Six months of plaque accumulation resulted in the establishment of an inflammatory lesion (pl-ICT) in the connective tissue of the periimplant mucosa, the location, size and composition of which did not differ between OA and TA sites. In addition, most OA and TA sites harbored a second inflammatory cell infiltrate in the tissue lateral to the abutment/fixture junction (ab-ICT). While pl-ICT was dominated by plasma cells and lymphocytes, ab-ICT contained a comparatively large number of polymorphonuclear leukocytes.Conclusion: The different surface characteristics of abutment made of c.p. titanium failed to influence plaque formation and the establishment of inflammatory cell lesions in the periimplant mucosa.

Electronic Resource

1600-051X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract. The aim of this retrospective clinical study was to evaluate the influence of different factors on the outcome of GBR treatment. 75 patients, who were not randomly assigned to the investigated parameters for clinical reasons, were included in the study. They presented with defect sites around implants and were treated with a xenogenic grafting material and a resorbable collagen membrane. The defect morphology was described, its dimension was measured and calculated at the time of implant installation and at re-entry. The success of GBR treatment was related to several clinical variables and possible correlations were evaluated. Defect sites around maxillary implants showed significantly more bone fill (96%) compared to those in the mandible (78%). The insertion of a provisional restoration during the healing period was also associated with significantly better results than when no provisional was inserted. Immediate and short-term delayed implant placements showed the best results both with 92% bone fill, when compared with long-term delayed placements with 80% bone fill (n.s.). In sites with type I bone quality (compact bone), a reduced bone fill was observed (64%). The results indicate that successful bone fill can be achieved with GBR; this is more feasible in the maxilla, when a provisional restoration is used. Early implant placement timings seem to be preferable due to the alveolar ridge preservation, more favorable defect morphologies and a higher regenerative capacity.

Electronic Resource