bluuebunny/crossref_metadata_2025 huggingface dataset:
Fixture design and overload influence marginal bone loss and future success in the Brånemark® system
Authors: Quirynen M. , Naert I. , Van Steenberghe D.
Published: March 2003

It has been documented that the long‐term clinical outcome of the Brånemark® system is very favourable. However, failures do occur before and after loading. This study examined the differences in marginal bone loss between standard and self‐tapping fixtures and attempted to explain excessive marginal bone loss or loss of osseointegration during the first 3 years of loading. Marginal bone loss (scored on long cone radiographs) and fixture failure rate were compared for different fixture designs. For standard fixtures, in comparison with self‐tapping fixtures, the failure rate was clearly higher before as well as after loading. However, for successful fixtures no difference in marginal bone loss was observed. For the conical fixtures an increased marginal bone loss around the smooth part was observed. The effect of fixture overload, marginal bone height and loss of osseointegration was examined in 69 patients with 1 and 15 patients with 2 fixed full prostheses, and in 9 patients with an overdenture in the upper jaw. Excessive marginal bone loss (more than 1 mm) after the first year of loading and/or fixture loss correlated well with the presence of overload due to a lack of anterior contact. the presence of parafunctional activity and osseointegrated full fixed prostheses in both jaws.
Antimicrobial treatment of peri‐implant infections
Authors: Mombelli A. , Lang N. P.
Published: March 2003

The purpose of this study was to investigate the possibility of antimicrobial treatment of peri‐implant infections associated with a periodontitis‐like subgingival microbiota. Nine partially or fully edentulous patients with titanium hollow cylinder implants were selected which showed loss of bone and probing depths ≥ 5 mm on one or several implants after at least 6 months following installation. They also yielded subgingival microbial samples with ≥ 106 CFU/ml, including ≥ 20% gram‐negative anaerobic bacteria, The treatment included mechanical cleaning, irrigation of all peri‐implant pockets > 3 mm with 0.5% chlorhexidine and systemic antimicrobial therapy (1000 mg ornidazole for 10 consecutive days). After therapy, bleeding scores decreased immediately and, over a one‐year observation period, remained significantly lower than before treatment. A significant gradual reduction in mean probing depths was detected over this one‐year period; only one case showed no improvement of local probing depth. Microbiological parameters indicated an instantaneous quantitative and qualitative change following treatment. Subsequently, several of these parameters tended to shift back towards pre‐treatment values. In the second half of the observation period, however. this tendency was reversed, and levels significantly different from baseline were eventually established. This study demonstrated that treatment aiming at reducing the subgingival bacterial mass and suppressing the anaerobic segment had a beneficial effect in patients suffering from peri‐implantitis.
Bacterial colonization of the internal part of two‐stage implants. An in vivo study.
Authors: Quirynen M. , Van Steenberghe D.
Published: March 2003

This study aimed to investigate the presence of microorganisms in the inner thread of the fixture (endosteal implant part) of the Brånemark™ system. In 9 volunteers the apical part of 2 abutment screws that had been in place for 3 months was examined by means of differential phase‐contrast microscopy. All screws harboured a significant quantity of micro‐organisms, mainly coccoid cells (86.2%) and nonmotile rods (12.3%). Motile organisms (1.3%) or spirochetes (0.1%) were only sporadically registered. A microbial leakage at the abutment/fixture interface probably is the most probable origin for this contamination.
The microflora adjacent to osseointegrated implants supporting maxillary removable prostheses
Authors: Smedberg J.‐I. , Svensäter G. , Edwardsson S.
Published: March 2003

The study examines the effect of maxillary prosthetic appliances on the composition of the microflora in the peri‐implant sulcus. Two groups of patients participated. One group consisted of 18 people with removable prostheses, and a second group of 9 people with fixed prostheses was chosen to match them in age. sex and function period of their prosthetic appliances. One implant site per patient was chosen for microbiological sampling, and the samples were taken on 2 separate occasions from all the subjects, with a 3‐month interval. From those with removable prostheses, a further sample was collected by scraping a squared area from the mucosal side of the prosthesis. The prevalence of black‐pigmented Porphyromonasl Prevotella. Actinohacllus actinomycetemcomitans, mutans streptococci, lactobacilli, enteric bacteria and yeasts was analysed using blood‐agar and selective agar media. The results show that the prevalence was significantly higher for Lactohacillus, Prevotella spp. and yeasts in subjects with removable prostheses than in subjects with fixed prostheses. No significant difference was registered in the pattern of microbial composition in subjects with the removable prosthesis when the peri‐implant sulcus plaque and the biofilm on the corresponding mucosal side of their prosthesis were examined. The insertion of a removable reconstruction to cover the area of the osseointegrated implants gave rise to a progressive change in the peri‐implant plaque towards a‐more aciduric micrdflora.
Augmentation of the rat mandible using guided tissue regeneration
Authors: Kostopoulos L. , Karring T.
Published: March 2003

The aim of the present study was to investigate whether it is possible to increase the height of the rat mandible at its inferior border using a bioresorbable membrane adapted to create a secluded space for ingrowth of bone tissue. The experiment was carried out in 18 rats. The mandibular ramus was exposed at both sides. A standardized titanium microimplant was then inserted in the naturally existing curvature at the inferior border of the mandible, serving as a fixed reference and space maker. The mandibular border on one side was covered with a polyhydroxybutyrate bioresorbable membrane, and the contralateral side, serving as control, received no membrane before closure of the wound. The membranes were placed in such a way that a space was created in the curvature between the membrane and the inferior border of the mandible. Macerated jaw specimens representing 6 months of healing demonstrated substantial amounts of bone formation in the curvature of the inferior border of the mandible, resulting in a flattening of the inferior border. Negligible amounts of bone formation had occurred in the control sides. Histological analysis demonstrated that. in 4 of 6 experimental specimens, the space created by the membrane was completely filled with new bone after 6 months of healing, but in some specimens soft tissue seemed to have migrated into the space through ruptures of the membrane or because of poor membrane adaptation at its lateral borders, thereby inhibiting bone formation. Only negligible bone formation had occurred at the control sides. It can be concluded that augmentation of the mandible can be accomplished using a bioresorbable membrane of polyhydroxybutyrate adapted to create a secluded space for ingrowth of bone tissue. but the membrane must be modified regarding its physical properties before clinical use in maxillofacial surgery.
Guided tissue regeneration in jawbone defects prior to implant placement
Authors: Lang N. P. , Hämmerle C. H. F. , Brägger U. , Lehmann B. , Nyman S. R.
Published: March 2003

The principle of guided tissue regeneration has been successfully applied for the regeneration of bone in various jaw defects in human. The purpose of this study was to assess the bone volume regenerated using nonresorbable membrane barriers. Nineteen patients with jaw bone defects of various sizes and configurations were included in the study. Combined split‐thickness/full‐thickness mucosal flaps were elevated in the area of missing bone. The size of the defects was assessed by measuring the distance from a reference line between 2 adjacent teeth (cementoenamel junctions) to the alveolar crest (a) every 2 or 3 mm. In addition, the crestal width was measured. Consequently, the surface of the triangle formed by a and the width of the crest as well as the volume between all triangles were calculated geometrically. Following the placement of Gore‐Tex® augmentation material as a barrier, the distance (b) to the top of the membrane from the reference line was assessed, and the maximum possible volume for bone regeneration based on (a‐b) and the width of the crest was calculated. At the time of membrane removal (3–8 months later). the same measurements were performed and the percentages of regenerated bone in relation to the possible volume for regeneration determined. In 6 patients in whom the membranes had to be removed early due to an increased risk for infection between 3 and 5 months, bone regeneration varied between 0 and 60%. In 13 patients in whom membranes were left for 6–8 months, regenerated bone filled 90–100% of the possible volume. It was concluded that successful bone regeneration consistently occurred with an undisturbed healing period of at least 6 months.
Histologic probe penetration in healthy and inflamed peri‐implant tissues
Authors: Lang N. P. , Wetzel A. C. , Stich H. , Caffesse R. G.
Published: March 2003

Periodontal probing is commonly used for assessing both the status of gingival health and the connective tissue attachment level around teeth.The role of probing around endosseous implants still remains unclear. The purpose of this study was to determine the histological level of probe penetration in healthy and inflamed mucosal tissues around implants. Five beagle dogs were used and a total of 30 one‐stage. Titanium Plasma Spary (TPS)‐coated implants of the ITI type were placed in the mandibles. After the healing period with meticulous oral hygiene. the dogs were divided into 3 groups: 1) clinical healthy mucosal tissues; 2) experimental mucositis (3 dogs); and 3) experimental ligature‐induced peri‐implantitis (2 dogs). Four months after implant placement, respectively 6 months in the third group, 60 probes were placed with a standardized force of 0.2 N and fixed at the mesial and distal aspects of the implants. Probing depth. clinical attachment level (CAL), Plaque index (PII) and Gingival Index (GI) were assessed throughout the study. Tissue sections were obtained for histometrical analysis. In the healthy group, the mean PII was 0.47. the GI 0.06 and the clinical probing depth (CPD) 2.12 mm. In the mucositis group the PII was 1.61, the GI 1.61 and the CPD 1.87 mm. In the peri‐implantitis group the PII was 1.96, the GI 2.05 and the CPD 3.73 mm. The histologic results show that the probes were able to identify the connective tissue adhesion level in the healthy group with a mean error of −0.05 mm (mean histologic probing depth (HPD): 1.75 mm) and, in the mucositis group, with −0.02 mm (mean HPD: 1.62 mm). Probe penetration increased with the degree of inflammation and in the peri‐implantitis group the probe exceeded the connective tissue level by a mean 0.52 mm (mean HPD: 3.8 mm). Therefore, probing around implants represents a good technique for assessing the status of peri‐implant mucosal health disease.
Plaque‐induced peri‐implantitis in the presence or absence of keratinized mucosa. An experimental study in monkeys.
Authors: Warrer K. , Buser D. , Lang N. P. , Karring T.
Published: March 2003

In 5 monkeys a total of 30 transmucosal endosseous dental implants were inserted in edentulous areas of the mandible with presence or absence of keratinized mucosa. After a healing period of 3 months with optimal plaque control, all implants were exposed to plaque accumulation for periods up to 9 months. To secure abundant plaque accumulation on half the number of the implants. cotton wool ligatures were placed around the implants at the entrance to the peri‐implant sulcus. Attachment loss was measured clinically and histometrically, and tissue recession was measured clinically. Ligated implants without keratinized mucosa demonstrated significantly more recession and slightly more attachment loss than the other implants. The results of this study suggest that the absence of keratinized mucosa around dental endosseous implants increases the susceptibility of the peri‐implant region to plaque‐induced tissue destruction.
Bone apposition onto oral implants in the sinus area filled with different grafting materials. A histological study in beagle dogs.
Authors: Wetzel A. C. , Stich H. , Caffesse R. G.
Published: March 2003

The placement of oral implants into jaw bone has a high predictability provided an adequate bone volume surrounding the implant is present to ensure primary stability and resistance to functional loading forces after completion of osseointegration. In the distal area of the maxilla, an adequate bone volume is often lacking because of the proximity of the sinus cavities. The aim of this study was to evaluate histologically the simultaneous placement of endosseous implants into the sinus cavity and the surgical elevation of the sinus floor including filling the cavity with different grafting materials. In 9 sinus areas of 5 beagle dogs, 9 titanium implants (ITI® Dental Implant System( were placed, and the void space of the sinus cavity was filled simultaneously with either demineralized freeze‐dried human cortical bone (Musculoskeletal Transplant Foundation), resorbable hydroxyapatite (Osteogen®) or natural cancelleous bovine bone mineral (Bio‐Oss®). To study bone formation, fluorochrome markers (tetracycline HCI and calcein green) were used at 2 and 8 weeks. Clinically, all implants healed uneventfully, and 5 months after implant placement the dogs were killed for histologic evaluation. All implants exhibited osseointegration within the pre‐existing cortical bone of the sinus floor. The implants surrounded by freeze‐dried bone xenografts yielded no formation of new bone, whereas the sites with hydroxyapatite or natural bovine bone mineral demonstrated newly formed bone with direct contact at the implant surface. The average extent of bone to implant contact was 25%(SD= 10.6%) and 27%(SD=8.8%), respectively in relation to the length of the originally denuded implant surface. In addition, the bone markers revealed a rapid bone formation and remodeling, especially around natural bovine bone mineral particles. This study yields new bone formation with direct contact to the implants surfaces in the sinus cavity into which suitable grafting materials were placed simultaneously. Resorbable hydroxyapatite (Osteogena) and natural cancellous bovine bone mineral (Bio‐Oss®) were osteoconductive and hence were suitable for bone formation around endosseous implants.
Maintenance of implants: an in vitro study of titanium implant surface modifications subsequent to the application of different prophylaxis procedures
Authors: Matarasso S. , Quaremba G. , Coraggio F. , Vaia E. , Cafiero C. , Lang N. P.
Published: March 2003

The aim of the present study was to evaluate surface alterations on titanium implant necks subsequent to different prophylaxis procedures. Fifty ITI implants were utilized. Forty implants were treated with 10 different prophylaxis procedures (ultrasonic scaler, plastic tip ultrasonic scaler, stainless steel curette, titanium curette, teflon curette, air powered system, abrasive rubber cups, polishing rubber cup and brush), and 10 implants were left as untreated controls. Surface alterations were studied on an area of 1mm×0.9mm and quantified using optical microscopic, SEM and laser prophylometer analysis. The use of the laser prophylometer provided an objective criterion for evaluation, expressing implant neck surface alterations in numeric values in terms of two roughness indexes, Ra and Rz. The results showed that, in comparison with the controls (Ra=0.50; Rz=3.98) the procedures investigated could be divided into 3 main groups:

1) Methods which altered the implant neck surface producing increased roughness (Ra=0.68–2.08; Rz=4.68–11.92);

2) Methods which left the implant neck surface unaltered (Ra=0.44–0.57: Rz=0.42–3.46);

3) Methods resulting in a smoothening of the implant neck surface (Ra=0.36; Rz=2.15).

Group 1 included procedures that should be avoided. However, it appeared safe to apply the procedures of groups 2 and 3. To confirm these results, it will be necessary to evaluate the plaque‐ and calculus‐removing efficacy from titanium neck implant surfaces in vivo.
C‐Telopeptide pyridinoline cross‐links (ICTP( and periodontal pathogens associated with endosseous oral implants
Authors: Oringer R. J. , Palys M. D. , Iranmanesh A. , Fiorellini J. P. , Haffajee A. D. , Socransky S. S. , Giannobile W. V.
Published: March 2003

Detection of periodontal or peri‐implant sites exhibiting progressing disease or those at risk of deterioration has proven difficult. Pyridinoline cross‐linked carboxyterminal telopeptide of type I collagen (ICTP), a marker specific for bone degradation found in gingival crevicular fluid (GCF), has been associated with both bone and attachment loss in periodontitis and may be useful for predicting disease activity. The aim of this cross‐sectional study was to examine the relationship between ICTP levels and subgingival species around implants and teeth from 20 partially and 2 fully edentulous patients. GCF and plaque samples were collected from the mesiobuccal site of each implant and tooth. Radioimmunoassay techniques were utilized to determine GCF ICTP levels. Plaque samples were analyzed utilizing checkerboard DNA‐DNA hybridization. Traditional clinical parameters were assessed. Seventy‐one implants and 370 teeth from 22 subjects were examined. ICTP levels and subgingival plaque composition were not significantly different between implants and teeth. Implant sites colonized by Prevotella intermedia, Capnoqtophaga gingivalis, Fusobacterium nucleatum ss vincentii, and Streptococcus gordonii exhibited odds ratios of 12.4, 9.3, 8.1, and 6.7, respectively of detecting ICTP. These results suggest a relationship between elevated ICTP levels at implant sites and some species associated with disease progression. Longitudinal studies are necessary to determine whether elevated ICTP levels may predict the development of per7‐implant bone loss.
Alveolar bone formation at dental implant dehiscence defects following guided bone regeneration and xenogeneic freeze‐dried demineralized bone matrix
Authors: Cho Kyoo‐sung , Choi Seong‐ho , Han Kyung‐ho , Chai Jung‐kiu , Wikesjö Ulf M. E. , Kim Chong‐kwan
Published: March 2003

The present study evaluated rate and extent of alveolar bone formation in dental implant dehiscence defects following guided bone regeneration(GBR) and implantation of xenogeneic freeze‐dried demineralized bone matrix (xDBM). A total of 16 titanium plasma‐sprayed (TPS) and 16 hydroxyapatite‐coated (HA) titanium cylinder implants were inserted in 4 mongrel dogs following extraction of the mandibular premolar teeth. Four implant sites per jaw quadrant (2 TPS and 2 HA implant sites) were prepared into extraction sockets in each dog. Buccal alveolar bone was removed to create 3 x 5 mm dehiscence defects. Two jaw quadrants in separate animals received GBR, GBR+xDBM, xDBM (control), or gingival flap surgery alone (GFS; control). Thus, four conditions were available for each implant type (TPS or HA): GBR, GBR+xDBM; xDBM and GFS. The animals received fluorescent bone labels to allow observations of rate and extent of bone formation. Animals were sacrificed at 12 weeks postsurgery and block sections were harvested for histologic analysis. There were no apparent histologic differences between TPS and HA implant defects. GBR and GBR+xDBM resulted in almost complete bone closure of the dental implant dehiscence defect. Rate of bone formation appeared higher following GBR alone. Extent of bone formation appeared somewhat greater following GBR+xDBM; however, delayed. xDBM alone did not adequately resolve the bony defect. In conclusion, GBR results in rapid, clinically relevant bone closure of dental implant dehiscence defects. Adjunctive implantation of xDBM does not appear to significantly improve the healing response in the model used.
Mk II: the self‐tapping Brånemark implant: 5‐year results of a prospective 3‐center study
Authors: Friberg B. , Nilsol H. , Olsson M. , Palmquist C.
Published: March 2003

The 5‐year result of a prospective 3‐center study is presented, comprising103 patients with 288 Mk II self‐tapping and 275 standard implants of the Brånemark System®. Out of 363 mandibular and 200 maxillary fixtures, one Mk II was lost of the lower jaw and 13 of each implant type failed in maxillae during the study period. Cumulative prosthesis stability was 97%. Five patients accounted for more than 85% of the fixture losses. Marginal bone resorption was similar for both implant designs. Apart from the implant failures and one patient exhibiting disturbed nerve sensation of the mental nerve, no major complications were encountered. Overall, this study revealed equal cumulative success rates for standard and Mk II implants after 5‐years of observation. Mandibular implants exhibited greater success rates (100%) for both tested implant types compared to maxillary implants (87%).
A comparative study of removal torque of endosseous implants in the fibula, iliac crest and scapula of cadavers: Preliminary report
Authors: Niimil A. , Ozekil K. , Uedal M. , Nakayama B.
Published: March 2003

This study was undertaken to compare removal torque of endosseous implants in the fibula, iliac crest and scapula of cadavers. The fibulae, iliac crests and scapulae were harvested from the right side of 5 formalin‐preserved cadavers. Endosseous implants (Brinemark System®) were placed at 3 points of each bone. The removal torque of the implant was measured by a torque gauge manometer (Tohnichi 15 BTG‐N). After measurement of there moval torque, the bone was cut at each implant site. The thicknesses of cortical and total bone were measured, The mean removal torques were 46.3 N cm in the fibulae, 15.2 N cm in the iliac crests and 2 1.4 N cm in the scapulae. There was a statistically significant difference in mean removal torque between the three bones. The total bone thicknesses were 11.7 mm in the fibulae, 9.9 mm in the iliac crests and 8.2 mm in the scapulae. The cortical bone thicknesses were 5.0 mm in the fibulae, 1.6 mm in the iliac crests and 1.8 mm in the scapulae. Significant correlation between the removal torque and the cortical bone thickness was found. However there was no significant correlation between the removal torque and the total bone thickness. In conclusion, the implants inserted in the fibulae showed the highest removal torques as compared to the ones inserted in the iliac crests and the scapulae. Moreover the removal torque was related to the thickness of the cortical bone in the implant sites.
Implant therapy involving maxillary sinus lift in periodontally compromised patients
Authors: Ellegaard Birgit , Kølsen‐petersen Jens , Baelum Vibeke
Published: March 2003

This study reports the results of implant therapy involving a sinus membrane lift as well as conventional implant therapy in 24 periodontally compromised patients who were treated during the period between June 1990 and May 1995. Patients were included on the basis of being in need of at least 2 implants, 1 of which was to be placed in the maxillary sinus region, and at least 3 mm bone height was required in the sinus region. Following fenestration of the lateral sinus wall and lifting of the sinus membrane sinus implants were inserted as described for conventional implants. Annual follow‐up visits included recording of plaque, probing pocket depth and bleeding on probing, and recording of the radiographic distance from the implant shoulder to the alveolar crest in mm. The Astra®, Astra® sinus, ITI®, and ITI® sinus were observed for an average of 30.8, 29.9,29.4 and 25.3 months, respectively. Of the 80 implants inserted 1 Astram and 2 ITI® hadfailed at 11–12 months and 1 ITI® had failed at 42 months. The Kaplan‐Meier estimate of the proportion of non‐failed implants at 36 months were lOO%, 95%, 9l%, and 86% for the Astra®, Astra® sinus, ITI®, and ITI® sinus implants, respectively. Of the Astra®, Astra® sinus, and ITI® implants, 71–82% remained free from bone‐loss ≥ 1.5 mm at 36 months. whereas this was the case for only 29% of the ITI® sinus implants. About 80–90% of the implants remained free from plaque; 65–86% remained free from bleeding; and 44–80% remained free from pockets ≥ 4 mm. These results indicate that the sinus lift technique can be used successfully in periodontally compromised patients.
The use of implant‐supported titanium prostheses for treatment of periodontally compromised patients including functional and orthodontic therapy. Report of 2 cases.
Authors: Knabe C. , Schendel K. U.
Published: March 2003

Due to its corrosion resistance and biocompatibility, titanium appears to be an alternative material for implant‐supported restorations. However, due to technological difficulties, the clinical application of titanium in implant restorations has been limited. Only after recent progress in technology could the clinical use of ceramo‐metal titanium restorations be recommended. The therapeutic repertoire for treating patients with missing teeth has been significantly expanded by modem implant methods. Osseointegrated prostheses have become an integral part of restorative therapy also for periodontally compromised dentitions. This article presents 2 case reports for the use of ceramo‐metal implant‐supported titanium cast prostheses for restorative treatment of periodontally compromised patients requiring comprehensive treatment involving periodontal, functional, orthodontic and prosthodontic therapy. Favourable clinical results have been obtained and a complication‐free service of these reconstructions has been documented throughout a 12‐ to 24‐month observation period. These observations suggest that implant‐supported ceramo‐metal titanium prostheses may be a valuable part of restorative therapy for periodontally compromised dentitions in that they facilitate restorations with optimal biocompatibility. However, controlled clinical studies are needed to establish the long‐term serviceability of these titanium restorations.
Some clinical and radiographical features of submerged and non‐submerged titanium implants. A 5‐year follow‐up study.
Authors: Schenk Günther , Flemmig Thomas Frank , Betz Thomas , Reuther Jürgen , Klaiber Bernd
Published: March 2003

The purpose of this controlled case series was to assess the adjunctive efficacy of controlled topical tetracycline HCl application in the treatment of infection associated periimplant mucositis or mucosal hyperplasia. Eight patients with at least 2 endosseous implants showing clinical signs of peri‐implant mucosal hyperplasia or mucositis were enrolled. All implants received supra‐ and subgingival scaling, with half of the implants receiving adjunctive controlled local delivery of tetracycline HCI (test). Control implants did not receive any other therapy aside from scaling. Clinical parameters were assessed at baseline, 4. and 12 weeks. Scaling plus controlled local delivery of tetracycline HCl markedly reduced peri‐implant mucosal hyperplasia in 4 of 5 test implants and demonstrated a trend towards a reduction of bleeding on probing scores. Scaling alone had no effect on mucosal hyperplasia in the 2 control implants presenting with this condition nor bleeding on probing scores. In both groups, plaque index scores were slightly reduced at 4 weeks but returned to baseline values at 12 weeks, whereas pocket probing depths, clinical attachment levels. and probing bone levels remained unchanged during the course of the trial. The observed trends suggest that scaling plus controlled local delivery of tetracycline HCI may have beneficial effects. Randomized controlled trials employing a sample size high enough to reach sufficient statistical power are needed to definitively assess the efficacy of controlled local tetracycline HCl delivery on peri‐impiant diseases.
An isolation and in vitro culturing method for human intraoral bone cells derived from dental implant preparation sites
Authors: Mailhot Jason M. , Borke James L.
Published: March 2003

In dental implantology, the biocompatibility of the osseous tissue to the implant surface and to local environmental factors plays an important role in the process of healing. Bone cells derived from intraoral osseous tissue proves to be an important source of the osteoprogenitor cells required for healing of the petiodontium around implants. Historically, the rat calvaria model has been employed to study the effects of various dental treatments on bone in Vito. However, there are morphological and functional differences which exist between bone cells derived from rat calvaria and human intraoral osseous tissue that impose certain limitations on the usefulness of the rat calvaria model for dental implant applications. Therefore, an in vitro culturing method for the isolation, growth and maintenance of human intraoral bone cell cultures derived from osseous tissues is truly warranted. In addition, a method for the accurate characterization of these bone cells as osteoblasts is also vital. The specific objective of this study was to establish isolation and in vitro culturing methods utilizing human intraoral bone cells derived from dental implant preparation sites. This paper describes techniques for the harvesting of human bone cells from the intraoral derived osseous tissues and discuss the procedures for maintaining the primary intraoral bone cell culture. In addition, our studies utilize established protocols for the characterization of these cells as osteoblasts by means of alkaline phosphatase activity determination, identification of cellular osteonectin and osteocalcin antigens, establishing the presence of cells expressing type I collagen and determining the ability of cells to produce calcifications. The utilization of intraoral osseous tissue may prove useful for future dental implant research by providing an in vitro model system more closely related to conditions encountered clinically.
Marginal bone levels at single tooth implants with a conical fixture design. The influence of surface macro‐ and microstructure
Authors: Norton Michael R.
Published: March 2003

The concept of a conical implant design to accommodate single tooth replacement, has previously been shown to result in excessive bone loss, around the machined titanium conical collar, usually down to the 1st thread. This unusually aggressive loss of bone was shown to occur within a short period of time, post loading, with greater than 3 mm of bone loss occurring within the 1st 6 months to 1 year. The influence of implant design, surface texture and microleakage have all been highlighted as a potential cause. A modification of the surface structure, both at the macroscopic and microscopic level, as well as an altered fixture‐abutment interface design has resulted in the maintenance of marginal bone around a single tooth titanium implant with a similar conical design. The radiographic follow‐up of 33 implants loaded for up to 4 years, has revealed, by comparison, a most favourable maintenance of marginal bone around the conical collar, with a mean marginal bone loss of 0.32 mm mesially and 0.34 mm distally for the whole group. The cumulative mean marginal bone loss mesially and distally is 0.42 mm and 0.40 mm from 1 to 2 years, 0.54 mm and 0.43 mm from 2 to 3 years, 0.51 mm and 0.24 mm from 3 to 4 years, and 0.62 mm and 0.60 mm for implants past their 4 year recall.
Inter‐ and intraobserver variability in radiographic bone level assessment at Brånemark fixtures
Authors: Gröndahl Kerstin , Sundén Solweig , Gröndahl Hans‐göran
Published: March 2003

The aim was to determine inter‐ and intraobserver variability in radiographic bone level assessments at Brånemark fixtures and to study the influence of various factors (radiographic density; projection geometry; jaw in which the fixtures were inserted; degree of bone loss; time after fixture loading; and number of radiographs of each fixture) on the variability. Intraoral radiographs from bridge connection and 1‐ and 3‐year check‐ups from 15 upper and 15 lower jaws (172 fixtures) were assessed by 6 observers. Measurements were taken from a reference point on the fixture to the marginal bone level, and some were repeated by all observers after 1 month. Results showed a small interobserver variation (0.14 mm) with the intraobserver variation (0.08 mm) as its largest component. The radiographic density and the degree of bone loss showed the strongest influence on the interobserver variation. The only variable with a significant effect on the intraobserver variation was the number of radiographs of each fixture. Calculated confidence values showed that measurement reliability can be improved by letting one observer or preferably more make several, independent readings, allowing for the demonstration of minor differences in bone height over time or between implant systems.
Effect of loading on bone regenerated at implant dehiscence sites in humans
Authors: Palmer Richard M. , Smith Brian J. , Palmer Paul J. , Floyd Peter D. , Johannson Carina B. , Albrektsson Tomas
Published: March 2003

Few investigations have studied the long‐term fate of bone formed following the technique of guided tissue regeneration. The aim of the present study was to evaluate bone fill around implant fixtures with dehiscence defects and to study its response to loading. Ten patients were treated with overdentures supported by 2 fixtures ad modum Brånemark. A third 7 mm x 3.75 mm diameter fixture was placed for the purposes of the study in the most anterior part of the mandible with a dehiscence defect of 4 to 5 mm on the buccal aspect (and 3 to 4 threads exposed) which was covered with a Gore‐Tex membrane and buried beneath the mucosa. Fixtures were exposed after 5 months (stage 2), ball abutments connected and loaded through an overdenture for 1 year. Nine fixtures were functioning well after 1 year of loading, 6 of which were retrieved with a trephine for histological examination and compared with 6 unloaded fixtures retrieved in our previously reported study. The bone area filling the thread profiles (BA%) and the bone to metal contact (BMC%) were measured in the 3 most apical and 3 most coronal thread profiles on the buccal and lingual surfaces. Statistically significant higher BMC% (P<0.01) were observed in loaded fixtures in the apical regions (buccal: loaded 51%. unloaded 25%; lingual: loaded 49%, unloaded 24%). Differences approached significance for the regeneration site (loaded 22%, unloaded 6%) but were no different for the coronal lingual region (loaded 28%, unloaded 20%). There were no differences for BA%. This study confirms that there is an increase in bone to metal contact with time and following fixture loading and that this may also occur with bone regenerated under Gore‐Tex membranes.
Autogenous masticatory mucosal grafts in extraction socket seal procedures: a comparison between sockets grafted with demineralized freeze‐dried bone and deproteinized bovine bone mineral
Authors: Tal Hahn
Published: March 2003

Successful preservation of the edentulous ridge after extractions may eliminate or reduce the need for ridge augmentation procedures. It has been claimed that grafting fresh extraction sockets and sealing them with auto now soft tissue grafts promote ridge preservation after tooth extraction. In this study, the survival of free autogenous connective tissue grafts sealing extraction sites was evaluated. In 24 healthy patients, 42 maxillary anterior teeth were extracted. After socket debridement, soft tissue margins of the socket orifice were carefully cut to remove epithelial debris. Sockets were filled with either demineralized freeze‐dried bone allografts (DFDBA) or deproteinized natural bovine bone mineral xenograft (DBBMX) to the level of the alveolar bone crest. Circular connective tissue grafts, slightly larger in diameter than the soft tissue socket orifice, were obtained and placed on top of the filler graft material sealing the sockets. Grafts were stabilized and secured by sutures and inspected weekly for the first month. The grafts were classified into 3 groups according to clinical parameters: vital, partially vital and non‐vital. After 1 week, 18 grafts were vital, 13 partially vital and 11 non‐vital. When only 1 sample unit (1 site per patient) was compared between DFDBA and DBBMX grafted sockets, no significant difference in graft vitality was shown (P=0.34 for vital; P=0.67 for vital plus partially vital). After 1 month, all socket orifices were sealed with mucosa. Based on the present observations, it seems that connective tissue grafts sealing fresh extraction sites are mainly dependent on underlying tissue vascularization and that sealing grafted fresh extraction sockets filled with bone substitute allograft or xenograft materials may be beneficial but an unpredictable procedure.
Response of rat bone marrow cells to differently roughened titanium discs
Authors: Castellani Roberto , de Ruijter Anja , Renggli Heinz , Jansen John
Published: March 2003

The purpose of the present in vitro study was to examine the effect of surface roughness on the behaviour of osteoblast‐like cells. Rat bone marrow RBM cells were cultured on commercially pure titanium discs. The discs were used as machined (TiM) or ground with 4000 (Ti 4000) or 320 (Ti 320) grit paper. Proliferation rate and alkaline phosphatase activity were determined, and morphology of the cells was studied with scanning electron microscopy (SEM). Besides. fluorescent markers, energy dispersive spectroscopy (EDS), X‐ray diffraction (XRD) and Fourier transform infrared (FTIR) were used to obtain quantitative and compositional information about the produced calcitied extracellular matrix (ECM). Results demonstrated after 2 days of incubation no significant difference in the percentage of attached cells to all substrates. At 5 days, Ti 320 surfaces showed significantly lower (P≤0.05) cell attachment Percentages compared with Ti M and Ti 4000 surfaces. At 8 days, Ti 320 surfaces showed significantly more (P≤0.05) cell attachment than the other surfaces. The Ti 4000 surfaces showed after 8 days significantly (P≤0.05) higher alkaline phosphatase activity compared to both other surfaces. At 15 days of incubation, the alkaline phosphatase activity on Ti 4000 substrates was significantly lower (P≤0.05) than on the other substrates. No significant difference in mineralized ECM formation was observed on the ground substrate compared to the machined substrates. Physicochemical analysis confirmed the apatite‐like nature of the deposited ECM on all substrates. On the basis of these findings, we concluded that our in vitro study could not clearly confirm the effect of surface roughness on the proliferation, differentiation and calcification of rat bone marrow cells.
A prospective clinical evaluation of different single‐tooth restoration designs on osseointegrated implants. A 3‐year follow‐up of Brånemark implants.
Authors: Wannfors Karin , Smedberg Jan‐ivan
Published: March 2003

Since single‐tooth implant restorations were introduced 12 years ago (Jemt 1986) there has been continuous development both in the technical design and the aesthetic outcome of the treatment. In order to ensure high quality in single‐tooth implant treatments a clinical follow‐up study was carried out on patients treated with modifications to the original regimen. In this study 69 consecutive patients were provided with 80 single‐tooth implant restorations. The patients were followed for 3 years. There was continuous development of the prosthetic design during the time of the study, allowing us to analyse possible prognostic differences for the different prosthetic treatments. This study confirms earlier reports which describe the single‐tooth implant treatment as a safe method with few surgical complications and minimal marginal bone loss. Only 1 implant was lost during the follow‐up period and the average marginal bone loss was 0.48 mm over the 3‐year follow‐up period. Crowns veneered with acrylic and with gold casted directly to the abutments, screwed onto the implants, led to recurring prosthetic complications and gave an appearance of rapid ageing. The first generation of crowns made following the Cera‐One design, sometimes produced a gap between the crown and the abutment associated with significant marginal bone loss during the first year. Few surgical or prosthetic complications were noted with cemented all‐ceramic constructions, although the number of these crowns in this study was limited.
Histomorphometrical analysis of bone formed in human maxillary sinus floor elevations grafted with OP‐1 device, demineralized bone matrix or autogenous bone. Comparison with non‐grafted sites in a series of case reports.
Authors: Groeneveld Erika H. J. , Van Den Bergh Johan P. A. , Holzmann Paulien , Ten Bruggenkate Chris M. , Bram Tuinzing D. , Burge Elisabeth II.
Published: March 2003

Bone morphogenetic proteins have proven to be effective bone inductors in animals and are therefore promising as inductors of bone formation in humans. In the present study we investigated the tissue formed after grafting osteogenic protein 1 on a collagen carrier (OP‐l‐device) in the human sinus floor elevation procedure. Three patients were grafted with OP‐1 device. For comparison 3 groups of 3 patients were included in the study receiving respectively, autogenous bone, human freeze‐dried demineralized bone matrix (DBM) or no graft. This last group had a sufficient alveolar bone height for dental implantation. Six months after grafting, at the time of implantation, biopsies were taken from the grafted area and/or the future dental positions. Undecalcified sections were used for histological and histomorphometrical analysis. All grafted sinuses showed an increased osteoid percentage when compared to non‐grafted sinuses. Autogenous bone grafts all showed lamellar bone formation. In the DBM grafts mostly woven bone had been formed, predominantly by what appeared to be osteo‐conduction. The OP‐1 device gave rise to bone formation in 2 of the 3 patients. After 6 months implants could only be placed in 1 out of the 3 patients treated with OP‐1 device. This patient showed mature lamellar bone formation, comparable to autogenous bone grafts. In the second patient all bone found was woven and the presence of a high osteoid percentage and large osteoeyte lacunae indicated that this was recently‐formed bone. Remnants of the collagen carrier were rare and new bone was never found against them, suggesting that this bone was formed by osteo‐induction. In the third patient no new bone had been formed. The device had been encapsulated with fibrous tissue and in‐flammatory reaction was present. We conclude that in the human sinus floor elevation OP‐1 has potential bone inductive capacity, but that results in the 3 patients tested with the current OP‐1 device are inconsistent.
Red blood cell and platelet interactions with titanium implant surfaces
Authors: Park Jun Y. , Davies John E.
Published: March 2003

The influence of the micro‐roughened surface, produced by dual acid‐etching (DAE) of machined commercially pure titanium, on initial blood cell/implant interactions was investigated by observing the blood components remaining at the implant surface following freeze‐fracture of clotted, and fixed, human blood. Glass surfaces were also used for immuno‐labelling studies to identify fibrin and platelets. The interface comprised predominantly fibrin and red blood cells (RBCs). The difference in distribution of RBCs was statistically significant (P<0.05) at 10 min of blood/implant contact, but diminished thereafter. Micro‐roughened DAE implant surfaces showed, qualitatively, more platelets than machined surfaces, while the textured glass surfaces demonstrated increased platelet aggregation. We believe that these early blood cell/implant interactions may play a key role in the osteoconduction stage of peri‐implant bone healing response to micro‐roughened implants.
Prosthetic management of the partially dentate patient with fixed implant restorations Note
Authors: Belser Urs C. , Mericske‐Stern Regina , Bernard Jean‐Pierre , Taylor Thomas D.
Published: March 2003

The aim of this chapter is to discuss the current prosthetic management of the partially dentate patient by means of fixed implant restorations in the scope of the ITI®Dental Implant System. For that purpose, the related statements defined by the participants of the prosthodontic section of the 1997 ITI Consensus Conference in Vitznau, Switzerland, will be presented, completed by explanatory comments where appropriate. Distinct conceptual differences will be made between the esthetic zone (areas of the dental arches where esthetic considerations are of primary concern) and the non‐esthetic zone (regions of the jaws where esthetic aspects do not represent a priority), and between single tooth replacement and multiple unit implant restorations. Furthermore, it is underlined that current clinical concepts should be based on both predictable treatment outcome and cost‐effectiveness. In this context, a straightforward surgical and prosthetic protocol is generally preferred in posterior locations of the oral cavity, using a nonsubmerged implant placement comprising an easily accessible implant shoulder location, and subsequently cemented implant restorations, basically according to a traditional prosthodontic approach. In esthetically demanding indications, where normally a distinctly submucosal implant shoulder location is advocated, screw‐retained restorations are preferred, based on prefabricated prosthetic components (e.g. machined cast‐on copings) to assure optimum surface properties and contour, and to achieve adequate marginal adaptation.
Lethal photosensitization for decontamination of implant surfaces in the treatment of peri‐implantitis
Authors: Dörtbudak Orhun , Haas Robert , Bernhart Thomas , Mailath‐Pokorny Georg
Published: March 2003

Abstract: Peri‐implantitis is considered to be a multifactorial process involving bacterial contamination of the implant surface. A previous study demonstrated that a combination of toluidine blue O (100 μg/ml) and irradiation with a diode soft laser with a wavelength of 905 nm results in an elimination of Porphyromonas gingivalis (P. gingivalis), Prevotella intermedia (P. intermedia), and Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) on different implant surfaces (machined, plasma‐flame‐sprayed, etched, hydroxyapatite‐coated). The aim of this study was to examine the laser effect in vivo. In 15 patients with IMZ implants who showed clinical and radiographic signs of peri‐implantitis, toluidine blue O was applied to the implant surface for 1 min and the surface was then irradiated with a diode soft laser with a wavelength of 690 nm for 60 s. Bacterial samples were taken before and after application of the dye and after lasing. The cultures were evaluated semiquantitatively for A. actinomycetemcomitans, P. gingivalis, and P. intermedia. It was found that the combined treatment reduced the bacterial counts by 2 log steps on average. The application of TBO and laser resulted in a significant reduction (P<0.0001) of the initial values in all 3 groups of bacteria. Complete elimination of bacteria was not achieved.