bluuebunny/crossref_metadata_2025 huggingface dataset:
Mucosal topography around implants in edentulous upper jaws. Photogrammetric three‐dimensional measurements of the effect of replacement of a removable prothesis with a fixed prosthesis.
Authors: Jemt T. , Book K. , Lie A. , Börjesson T.
Published: March 2003

A photogrammetric technique was tested to measure the topography of the mucosa around implants, placed in edentulous upper jaws. Photographs were taken of casts from 6 patients, who all had used a removable overdenture for one year. Another series of photographs was taken on new casts after the use of a fixed prosthesis for a second year. The 6 pairs of photographs were measured and compared in an analytical stereo plotter for surface contour and implant positions. The results from the measurements indicated a trend of general recession of the mucosa after one year with fixed prosthesis. both on the buccal as well as on the palatal side. The mean volume of recession was 222.4 mm3, corresponding to an average of 0.4 mm3/mm2 of mucosa. More recession was generally observed on the palatal side, but obvious variations between the patients were present. In conclusion, the photogrammetric technique was considered to be well suited for analysing tissue contours in various dental situations.
Microvascular adaptation to transmucosal implants. A scanning electron microscopic study in the rat.
Authors: Selliseth N. J. , Selvig K. A.
Published: March 2003

The profuse gingival microvasculature surrounding natural teeth has a unique architecture that contributes to the biologic seal and the anti‐infective defense in the sulcular region. This study tested the hypothesis that this characteristic vascular arrangement is not replicated when gingival tissues adapt to a transmucosal implant. In 20 4‐week‐old Wistar rats, the upper first molar was extracted bilaterally and the gingiva at this site excised. Four weeks later, a 5‐mm‐long titanium screw was implanted at the extraction site on one side. After another 4 weeks, the rats were injected with liquid plastic resin through the carotid arteries and vascular casts prepared for scanning electron microscopy. The results showed that, within 4 weeks after implant insertion, the microvasculature of the regenerated soft tissues immediately surrounding the implant had formed a characteristic arrangement that consisted of a dense subepithelial network as well as an orderly array of vertically oriented capillary loops. The density and diameter of the capillaries varied within a wide range, possibly related to the extent of healing and/or inflammatory conditions. On the contralateral, edentulous side, the capillaries formed a flattened meshwork showing a conspicuous absence of capillary loops. This study indicates that, when a transmucosal implant is inserted in an edentulous area, the mucosal microvasculature adapts and forms an arrangement very similar to that surrounding natural teeth.
Ten‐year survival rates of fixed prostheses on four or six implants ad modum Brånemark in full edentulism
Authors: Brånemark P.‐I. , Svensson B. , Van Steenberghe D.
Published: March 2003

A series of 1.56 consecutive fully edentulous patients were rehabilitated by means of fixed prostheses on either 4 or 6 screw‐shaped titanium implants. This retrospective study calculated survival rates for both prostheses and individual implants. Only patients with a 10‐year follow‐up were considered. The implant lengths were 10 (90%) or 7 mm. They were all inserted after pretapping. In the mandible 13 and 59 prostheses were installed on respectively 4 and 6 implants. In the upper jaw the respective numbers were 14 and 70. Both groups (4 versus 6 implants) were age‐ and gender‐matched. A reduced jaw bone volume was the major reason for limiting the number of implants to 4. Although a tendency existed for an increased failure rate in patients with only 4 implants, the survival rate for both individual implants and prostheses was the same in both groups at the end of the 10‐year observation period. The present tendency of some clinicians to install as many implants as possible in full edentulism should be seriously questioned.
Loss of osseointegration caused by occlusal load of oral implants. A clinical and radiographic study in monkeys.
Authors: Isidor Flemming
Published: March 2003

The breakdown of bone around oral implants following excessive occlusal load or plaque accumulation was evaluated in monkeys. 5 screw type implants of pure titanium (Astra) were inserted in the mandible of 4 monkeys (Macaca Fascicularis). 2 implants were placed in each of the lateral segments and 1 in the frontal area. Each monkey was provided with 2 cemented splints covering the premolars and molars in the right and left side of the maxilla, respectively. 6 months after insertion of the fixtures, a fixed partial prosthesis was mounted on the 2 implants in one of the lateral segments. The prosthesis was in supra‐occlusal contact with the antagonizing splint. Each prosthesis was replaced during the course of the experiment. The renewed prosthesis caused a lateral displacement of the mandible during occlusion. and therefore resulted in a lateral rather than axial excessive occlusal load. Implants retaining the prosthesis were brushed 1 × a week and subgingival cleaning was performed 1 × a month. The remaining implants were never cleaned and. additionally, a cotton cord was placed passively around each of these to promote plaque accumulation. 5 out of 8 implants with excessive occlusal load lost osseointegration (mobility and peri‐implant radiolucency). The loss of osseointegration was observed 4.5 months to 15.5 months after the occlusal overload was commenced. None of the implants with plaque accumulation lost osseointegration, although an average loss of I .8 mm in the radiographic bone level was assessed after 18 months.
Rehabilitation of mandibular edentulism by single crystal sapphire implants and overdentures: 3–12 year results in 86 patients. A dual center international study.
Authors: Fartash B. , Tangerud T. , Silness J. , Arvidson K.
Published: March 2003

86 patients, in 2 Scandinavian centers, participated in a prospective study of mandibular edentulism, treated with overdentures supported by Bioceram sapphire implants. Implant success and prosthesis stability as well as parameters for peri‐implant health were evaluated. Masticatory function and complications were also documented. The study began in 1982 and clinical treatment of the last patients was completed in 1991. The patients have been followed for at least 3 years, and up to 12 years. 4 patients were lost to follow‐up. Of the initial 324 implants, 7 implants failed before prosthetic treatment. 3 patients lost 1 implant each within the 1st year, and 4 patients lost all 4 implants. 16 implants were lost between 36 and 42 months in function, due to lack of osseointegration and pain. The loss of implants could be attributable to an association, not statistically verified, between bone quality and anatomy, with heavy smoking as a risk factor. Based on the remaining implants, the cumulative implant success rates were 95.2%, 91.3%, 91.3%, 91.3% at 3, 5, 10 and 12 year follow‐up, respectively. The cumulative success rates for overdentures were 96.4%, 92.8%, 92.8% and 92.8% respectively, for the same follow‐up periods. Indices for the health of the peri‐implant mucosa disclosed no serious inflammatory reactions in the surrounding soft tissues. Patient satisfaction with this form of oral rehabilitation was high in all but 2 patients who experienced discomfort.
Transversal fixation of restorations in combination with the Octa abutment of the ITI dental implant System®
Authors: Sutter F. , Grande V. , Sutter Jr. F. J. , Brägger U. , Lang N. P.
Published: March 2003

In aesthetically demanding locations of the dentition, the replacement of a single tooth by means of an oral implant is often difficult because of technical limitations of the abutment systems used. The Transversal Fixation System® in combination with the Octa® abutment of the ITI Dental Implant System® presents a novel development to overcome these limitations. The report describes the engineering and design of this technical development.
A clinical retrospective evaluation of FA/HA coated (Biocomp®) dental implants. Results after 1 year.
Authors: Cune M. S. , Van Rossen I. P. , De Putter C. , Wils R. P. J.
Published: March 2003

In this retrospective clinical evaluation, the performance of loaded titanium implants with a bilayer bioactive surface coating of the relatively reactive hydroxylapatite (HA. outer layer) and the more stable fluorapatite (FA, inner layer) was evaluated. 98 consecutive patients were included in the study for a total of 354 implants, loaded by overdentures, fixed partial dentures and single tooth replacements. Statistical analyses revealed a cumulative probability of implant survival on a per patient basis of 94.5%(s.e. 2.7%) one year after implant installation. On implants that were lost parts of the bilayer FA/HA coating had vanished as a result of primary or secondary infection and subsequently epithelial down growth. Most complications were associated with implants placed in the maxilla. Periotest values (PTV) were generally high, indicating adequate osseointegration. The PTV's were statistical significantly less favorable in implants placed in the maxilla. The most favorable PTV’s and gingival index scores were found around implants servicing overdentures. Marginal bone loss averaged ‐ 2mm during the observation period. The amount of marginal bone loss corresponded with the distance from the neck of the implant to the first thread of the implant's cervical screw‐section. It is concluded that, during the relatively short observation period, the FA/HA coated implants function adequately. However, in the absence of a direct implant‐to‐bone contact preceding implant loss, part of the FA/HA coating on the titanium implants generally dissolves.
Bone augmentation at titanium implants using autologous bone grafts and a bioresorbable barrier. An experimental study in the rabbit tibia.
Authors: Lundgren A. K. , Sennerby L. , Lundgren D. , Taylor A. , Gottlow J. , Nyman S.
Published: March 2003

The aim of the present investigation was to compare the effect of using autologous bone particles covered with a bioresorbable matrix barrier with the use of bone particles alone on bone augmentation at titanium implants installed in the rabbit tibia. Two Brånemark System® implants, one in each tibia, were inserted in each of 9 rabbits in such a way that 5 threads were not covered with bone. Autologous bone particles were harvested from the skull and placed over the exposed implant surfaces on each tibia. The bone graft on one tibia was covered with a Guidor® Matrix Barrier, while the bone graft on the other tibia served as a control. After a healing period of 12 weeks, the animals were sacrificed and specimens taken for histomorphometrical analyses. The analyses showed that a significantly larger volume of augmented bone tissue had formed at the test sites. There were, however, no differences in the amount of mineralized bone. In fact, the difference in tissue volume was due to an increased amount of bone marrow at the test sites. The degree of mineralized bone to implant contact as well as the degree of mineralized bone within the threads at the test implants were similar to that at the controls. In conclusion, it was found that the coverage of particulate autologous bone grafts with a bioresorbable barrier resulted in a larger volume of augmented bone than the use of bone grafts not covered with a barrier.
An in vitro evaluation of the strength of an internal conical interface compared to a butt joint interface in implant design
Authors: Norton Michael R.
Published: March 2003

Dental implants are subject to large and highly complex loads of varying magnitude, duration and vector. Bridge performance is closely related to load transmission both at the bone to implant interface and between components within the implant‐abutment‐bridge cylinder complex. The design of the interface between components within this complex may have a profound influence on the long term function of the implant supported prosthesis. An in vitro evaluation of implants 3.5 mm in diameter, utilizing an internal conical interface has demonstrated increased resistance to bending moments at the fixture‐abutment interface (P=0.00010) and at the abutment‐bridge cylinder interface (P< 0.01) when compared to a standard 3.75 mm implant with a hex mediated, butt joint interface. The relatively small values for co‐efficient of variance measured in both systems would conmthat whilst the size of data is small, it is nonetheless a reliable indication of the relative strength of these implant designs.
The mini bottle brush ‐ a new fastening device in cancellous bone
Authors: Krysander Lennart , Hellem Sölve , Berggren Anders , Klinge Björn
Published: March 2003

A new design for bone implants, the bottle brush. was recently presented in a pilot study on marrow cavities in the femur of rabbits. In this study, the concept is further evaluated on a mini bottle brush. The fixture, 5x7 mm, with an implant shaft made of CP‐titanium and bristles of nylon coated with sputtered titanium, was inserted into the cancellous bone of the medial femoral condyle in 15 adult rabbits. The titanium fixture was compared with a similar brush without the titanium sputtered surface. The animals were sacrificed after 4 months and the quantity and quality of bone integration were evaluated with pull‐out tests and histological examination. In both parameters, the values were significantly higher for the titanium‐sputtered brushes, with removal forces similar to titanium cylinders of the same size and with a bone‐to‐metal contact area of about 50%.
Densitometric measurements of the mandible: accuracy and validity of intraoral versus extraoral radiographical techniques in an in vitro study
Authors: Verhoeven Jan W. , Ruijter Jan M. , Cune Marco S. , De Putter Cornelis
Published: March 2003

In this study a comparison is made between intraoral and extraoral radiographical techniques for quantitative measurements of bone density in the edentulous mandible. A phantom model, composed of a dry mandible surrounded by a soft tissue substitute was used. Radiographs were made of aluminium implants of known volumes. Intra‐ and extraorally placed reference wedges of aluminium or a combination of aluminium and Plexiglas were used for the measurement of the aluminium volume of the above‐mentioned implants and compared with the real volume. The IBAS image analysis system was used for image processing and measurements. A systematic deficit in the measured volume of 15 to 29% was found. This error was irrespective of the radiographical technique and indicates a constant underestimation of the aluminium volumes. The differential influence of the secondary radiation on the images of the jaw and the wedge is proposed to be a possible cause of this constant underestimation. The intraoral and extraoral techniques do not display significant statistical differences in the levels of validity or accuracy. Obtaining serial intraoral radiographs of adequate quality in the atrophic edentulous mandible can be problematic. It is concluded from this in vitro study that in these cases Oblique Lateral Cephalometric Radiographs may provide a valuable alternative for quantitative image analysis.
Peri‐implant conditions in periodontally compromised patients following maxillary sinus augmentation A long‐term post‐therapy trial
Authors: Buchmann Rainer , Khoury Fouad , Faust Christina , Lange Dieter E.
Published: March 2003

Augmentation of the maxillary sinus in the atrophied edentulous posterior maxilla is an integral part of implant prosthodontics. This study examined the clinical outcome in 50 periodontally compromised successfully treated subjects with severe maxillary atrophy following oral implantation with Bråemark. IMZ or Frialit‐2 endosseous implants between 1991 and 1994. Simultaneous sinus augmentation was achieved using auto‐genous bone grafts harvested from the anterior mandible. Oral implants in 37 periodontally healthy patients directly placed in the stable local maxillary bone served as controls. The oral rehabilitation included implant supported restorations or removable superstructures over a period between 3 and 5 years. The peri‐implant status of implant abutments inserted in the periodontal compromised augmented maxilla resulted in values comparable to the local maxillary bone except for the GCF rates with enhanced levels of 63.9±49.9 (controls 37.9±40.7). The average peri‐implant Periotest values in the augmented maxillary sinus (test group) were −3.1 PT and +0.2 PT in the controls. The Periotest scores in the sinus area ranked between −7.0 and +5.0 with mean PT values of −1.5 for IMZ, −3.2 for Bråemark and −4.0 for Frialit‐2 abutments. The functional integration of oral implants following sinus augmentation with autologous bone grafts and conventionally placed endosseous implants in the local bone was similar. The additional implant stabilization within the mandibular cortical bone grafts resulted in very low Periotest scores. In periodontally compromised subjects treated for chronic adult periodontitis with minimal maxillary bone height less than 5 mm the endosseous implantation with simultaneous sinus augmentation is recommended as an appropriate technique for long‐term oral implant rehabilitation.
Regeneration of bone graft donor sites
Authors: Miller Neal A. , Penaud Jacques , Kohler Chantal , Ambrosini Pascal
Published: March 2003

When crestal volume is greatly insufficient for the placement of dental implants, bone grafting is usually the most reliable ridge augmentation procedure. The grafts are most often taken in paral or mandibular symphysis regions. Though not too noticeable, it seems contra‐indicated and even potentially dangerous to leave zones like the cranium to repair spontaneously. Guided bone regeneration techniques have shown their ability to regenerate new bone under difficult conditions in jaws. Their use in bone graft donor sites is simple and the results are consistent. This report shows that 2 types of resorbable membranes are equally as efficacious in terms of new‐bone formation.
Augmentation of calvarial tissue using non‐permeable silicone domes and bovine bone mineral. An experimental study in the rat.
Authors: Slotte Christer , Lundgren Dan
Published: March 2003

The aim of the present study was to evaluate the effect of bovine bone mineral placement as an adjunct to a guided bone regeneration (GBR)‐barrier in experimental bone augmentation. Some 18 Sprague‐Dawley rats underwent flap surgery in which non‐permeable silicone domes were placed on the calvaria. A test group of 9 animals received domes filled with cancellous deproteinized bovine bone mineral (Bio‐Oss®). The domes of 9 control animals were left empty. The experiment was terminated after 8 weeks of healing. Inspection after histologic preparation found no signs of any foreign body reaction to the implanted bovine bone mineral, which seemed to be well integrated with the augmented tissue. The control specimens healed uniformly with new bone inside the domes at the base of the calvaria. The tissue inside the domes of the test specimens had a completely different architecture with new bone both at the base of the calvaria and at a distance from the base, surrounded by and in close contact with non‐mineralized tissue and remaining bovine bone mineral. Some ingrowth of soft connective tissue, most likely from the sagittal skull suture could be seen in most test and control specimens. Histomorphometric analysis revealed that the total amount of augmented tissue was significantly greater in the test group (x=1.93±O.21 mm2) than in the control group (x=0.99±0.22 mm2), P<0.00l). The control domes contained 0.73±0.28 mm2 augmented bone, while the corresponding value for the test specimens was 0.35±0.13 mm2, significantly less than the controls (P<0.01). The test domes contained 0.83±0.15 mm2 newly‐formed non‐mineralized calvarial tissue, significantly more than the controls (x=0.26±0.16 mm2), P<0.00l). Remaining particles of bovine bone mineral constituted 0.76±0.14 mm2, or 39%, of the total amount of augmented tissue in the test group. A considerable shrinkage to about 69% of the height of the initial fill of bovine bone mineral at surgery appeared in the test domes after 8 weeks of healing. The reason for this was probably more due to a denser packing of the bovine bone mineral during healing than to resorptive activity. It was concluded that implantation of bovine bone mineral combined with GBR technique significantly enhances augmentation of calvarial tissue. Early mineralization, however, seems to be retarded compared to non‐filled control specimens. Further studies should be made to determine the long‐term maturation of augmented tissue including resorption pattern of the bovine bone mineral.
Early colonization of dental implants by putative periodontal pathogens in partially edentulous patients
Authors: Van Winkelhoff Arie J. , Goené Ronnie J. , Benschop Claudia , Folmer Tiddo
Published: March 2003

There is limited scientific information available on the early colonization of the peri‐implant pockets in partially edentulous individuals. Knowledge about this process is one step in better understanding the etiology and pathogenesis of peri‐implantitis. In this study, the early colonization of the peri‐implant pockets by putative periodontal pathogens was studied in 20 partially edentulous individuals using anaerobic culture techniques. At baseline, the presence and levels of putative periodontal pathogens in the microflora of periodontal pockets and saliva were established. Immediately after loading of the titanium implants and after 6 and 12 months the presence and levels of selected putative periodontal pathogens were determined in periodontal and peri‐implant pockets. A second aim was to detect bacterial contamination of the implant site and the inside of the implant. At baseline, the most frequently isolated species from the periodontal pockets were Fusobacterium nucleatum, Prevotella intermedia and Peptostreptococcus micros. Bacteroides forsythus, Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were isolated from 9, 2 and 3 patients respectively. Six months after placing of the bridges, the majority of the implant sites had detectable levels of most periodontal bacterial species with the exception of A. actinomycetemcomitans which could not be isolated from any of the peri‐implant samples during the experimental period, although 2 patients had this organism at baseline. In 2 patients with detectable subgingival P. gingivalis at baseline this species was found after 12 months in the peri‐implant sites. One of these patients lost 2 implants which was associated with a high proportion of P. gingivalis in the peri‐implant pockets. A second patient developed 2 fistulas around 2 implants at 8 months and this event was also associated with the presence of P. gingivalis. It is concluded that proper periodontal infection control before instalment of dental implants in partially edentulous patients may prevent early bacterial complications.
The scientific basis for and clinical experiences with Straumann implants including the ITI® Dental Implant System: a consensus report	Note
Authors: Cochran David L.
Published: March 2003

Successful endosseous implant therapy requires integration of the implant with bone, soft connective tissue and epithelium. This report from a consensus conference on Straumann dental implants including the ITI® Dental Implant System documents the interaction of these nonsubmerged one‐piece implants with the oral tissues and reviews clinical studies supporting the high success achievable with these implants in patients. Light and electron microscopy reveal that epithelial structures similar to teeth are found around the implants. A connective tissue zone exists between the apical extension of the junctional epithelium and the alveolar bone. This connective tissue comprises a dense circular avascular zone of connective tissue fibers surrounded by a loose vascular connective tissue. The histologic dimensions of the epithelium and connective tissue comprising the biologic width are similar to the same tissues around teeth. The nonsubmerged one‐piece design of the Straumann implants, which have been used for over 20 years, has set a standard in implant dentistry, with other implants now being manufactured and placed using similar techniques. Straumann implants have an endosseous portion that is either coated with a well‐characterized and well‐documented titanium plasma‐sprayed surface or is sandblasted and acid attacked. Both surfaces have been shown to have advantages for osseous integration compared to machined and other smoother implant surfaces. These advantages include greater amounts of bone‐to‐implant contact, more rapid integration with bone tissue, and higher removal torque values. The lack of component connection at or below the alveolar crest provides additional benefits. Component connection at the alveolar crest, as seen with submerged implants, results in microbial contamination, crestal bone loss and a more apical epithelial location. Numerous human clinical trials document the successful use of Straumann implants in a variety of indications and areas of the mouth. These include prospective long‐term trials using strict criteria of success and life table analyses. Taken together, the clinical studies reveal that Straumann implants can be used predictably in partially edentulous and completely edentulous maxilla and mandibles with high success rates. Furthermore, the animal and microscopic studies reviewed provide a scientific basis for the integration of Straumann implants with bone, connective tissue and epithelium.
Biological complications with dental implants: their prevention, diagnosis and treatment Note
Authors: Lang Niklaus P. , Wilson Thomas G. , Corbet Esmonde F.
Published: March 2003

Biofilms form on all hard non‐shedding surfaces in a fluid system, i.e. both on teeth and oral implants. As a result of the bacterial challenge, the host responds by mounting a defence mechanism leading to inflammation of the soft tissues. In the dento‐gingival unit, this results in the well‐described lesion of gingivitis. In the implanto‐mucosal unit, this inflammation is termed “mucositis”. If plaque is allowed to accumulate for prolonged periods of time, experimental research has demonstrated that “mucositis” may develop into “periimplantitis” affecting the periimplant supporting bone circumferentially. Although the bony support may be lost coronally, the implant still remains osseointegrated and hence, clinically stable. This is the reason why mobility represents an insensitive, but specific diagnostic feature of “periimplantitis”. More sensitive and more reliable parameters of developing and existing periimplant infections are “bleeding on probing”, “probing depths” and radiographic interpretation of conventional or subtraction radiographs. Depending on the diagnosis made continuously during recall visits, a maintenance system termed Cummulative Interceptive Supportive Therapy (CIST) has been proposed.
Absorbable versus nonabsorbable membranes and bone grafts in the treatment of ligature‐induced peri‐implantitis defects in dogs
Authors: Nociti Francisco H. , Machado Maria Ângela N. , Stefani Cristine M. , Sallum Enilson A. , Sallum Antonio W.
Published: March 2003

Abstract: The purpose of this study was to clinically evaluate an absorbable collagen membrane (Bio‐Gide®) and a nonabsorbable polytetrafluoroethylene membrane (PTFE), associated or not with bone grafts, for the treatment of ligature‐induced peri‐implantitis defects in dogs. The bilateral mandibular premolars were removed from 5 2‐year‐old mongrel dogs. After 3 months of healing, 3 titanium implants were placed on each side of the mandible. Experimental peri‐implantitis was induced after abutment connection. Ligatures and abutments were removed after 1 month and the bone defects were randomly assigned to one of the following treatments: DB: debridement alone; GBR+BG‐I: debridement plus PTFE membrane associated with mineralized bone graft (Bio‐Oss®); GBR+BG‐II: debridement plus collagen membrane (Bio‐Gide®) associated with mineralized bone graft; GBR‐I: debridement plus PTFE membrane; GBR‐II: debridement plus collagen membrane; BG: debridement plus mineralized bone graft. The peri‐implant bone defects were measured before and 5 months after treatment. Results showed the greatest percentage of vertical bone fill for GBR+BG‐II (27.77±14.07) followed by GBR‐II (21.78±16.19), BG (21.26±6.87), GBR+BG‐I (19.57±13.36), GBR‐I (18.86±10.63) and DB (14.03±5.6). However, the values were not statistically significant (ANOVA, contrast F test, P=0.612). Within the limits of the present investigation, it can be concluded that no difference was detected among treatments.
A clinical histologic study of bovine hydroxyapatite in combination with autogenous bone and fibrin glue for maxillary sinus floor augmentation
Authors: Hallman Mats , Cederlund Andreas , Lindskog Sven , Lundgren Stefan , Sennerby Lars
Published: March 2003

Abstract: Biopsies were taken from 16 out of 20 consecutive referral patients 6 to 8 months after maxillary sinus floor augmentation with a mixture of bovine hydroxyapatite (BH), autogenous bone particles and fibrin glue. Four days prior to biopsy retrieval the patients were given a single dose of tetracyclin to label bone forming sites. Fluorescence microscopy of 100 μm thick sections revealed active bone formation in conjunction with the BH particles in 14 of 15 specimens analysed. Light microscopy and morphometry of ground sections from 16 patients showed various amounts of mineralised bone tissue in all except one specimen. In the latter case, the BH particles were encapsulated by a dense fibrous connective tissue. Sections from the augmented areas were occupied by non‐mineralized tissue (54.1+12.6%), lamellar bone (21.2+24.5%), BH particles (14.5+10.3%) and woven bone (10.2+13.4%). The non‐mineralized tissue seen in bone forming areas consisted of a loose connective tissue, rich of vessels and cells, and in the periphery of a more dense fibrous connective tissue. Woven bone with large and scattered osteocyte lacunae was bridging between the BH particles and the lamellar trabecular bone. There were no signs of resorption of the BH particles. The lamellar bone appeared to have originated from the recipient site and was seldom in contact with the BH particles. It is concluded that the tested implant material has bone conducting properties. The bone associated with the BH particles after 6 to 8 months of healing was mainly woven.
Glass fiber‐reinforced abutments for dental implants. A pilot study
Authors: Behr M. , Rosentritt M. , Lang R. , Handel G.
Published: March 2003

Abstract: Titanium abutments in dental implants shine through all‐ceramic crowns and therefore limit excellent esthetic results. Prototypes of tooth‐colored fiber‐reinforced abutments were investigated to avoid the shining‐through effect. In vitro, the fracture strength was determined after thermal cycling and mechanical loading of all‐ceramic single crowns and four‐unit bridges made of a fiber‐reinforced composite. The suprastructures were adhesively fixed onto fiber‐reinforced implant abutments and compared with those fixed on standard titanium abutments. The median of the fracture strength of the titanium‐supported all‐ceramic crowns was significantly higher than the median of crowns fixed onto the prototypes. But this value was still more than twice as high as the maximum loading force under oral conditions. No statistical difference was found between four‐unit bridges made by fiber‐reinforced composite inserted onto titanium abutments and those inserted onto fiber‐reinforced abutments. Fiber‐reinforced abutment prototypes for dental implants avoided the shining‐through effect associated with metal abutments. Their load‐bearing capacity after in vitro stress simulation was higher than the maximum oral loading force. With some improvements, the fiber‐reinforced implant abutments are therefore a promising alternative to titanium abutments.
Effect of recombinant human bone morphogenetic protein‐2 on bone regeneration and osseointegration of dental implants
Authors: Sykaras Nikitas , Triplett Robert G. , Nunn Martha E. , Iacopino Anthony M. , Opperman Lynne A.
Published: March 2003

Abstract: Recombinant human bone morphogenetic protein‐2 (rhBMP‐2) induced bone regeneration and osseointegration was evaluated in bony defects created within the hollow chamber of endosseous dental implants in 14 foxhound dogs. Bilateral extractions of mandibular premolars were performed and surgical implantation of 104 hollow cylinder implants followed after 8 weeks of healing. Experimental implants had their hollow chamber filled with 20 μg of rhBMP‐2 delivered with a bovine collagen carrier, whereas the control implants had their apical chamber left empty. Dogs were followed for 2, 4, 8 and 12 weeks. Histomorphometric evaluation and immunohistochemical analysis were performed. Minimal bone was regenerated at 2 weeks for both groups. At 4 weeks, bone fill averaged 23.48% for the rhBMP‐2 and 5.98% for the control group (P<0.05). At 8 weeks, mean bone fill was 20.94% and 7.75% for the rhBMP‐2 and the controls, respectively (P<0.05). At 12 weeks, mean bone fill was 31.39% and 24.31% for the rhBMP‐2 and control implants, respectively (P>0.05). Bone‐implant contact (BIC) increased for both groups over time and at 8 weeks the rhBMP‐2 BIC value was 18.65% and for the control 7.22% (P<0.05). At 12 weeks, the BIC was 43.78% and 21.05% for the rhBMP‐2 and the control group, respectively (P<0.05). Immunohistochemical staining for type II collagen was positive only for parts of the collagen carrier and formation of cartilaginous intermediate was not observed in any of the specimens. The results suggest that, in confined defects adjacent to dental implants, rhBMP‐2 can induce bone regeneration in close apposition to the implant surface.
Bicortical titanium screws for critical orthodontic anchorage in the mandible: a preliminary report on clinical applications
Authors: Freudenthaler Josef W. , Bantleon Hans‐Peter , Haas Robert
Published: March 2003

Abstract: Critical anchorage during orthodontic treatment in the mandible needs both time and effort and patient compliance. In 8 patients, 12 bicortical titanium screws (BIS) were used as anchorage units for orthodontic molar protraction. The criteria for patient selection were: critical anchorage in the lower jaw (i.e. retraction of anterior teeth undesirable) and molar extraction sites. After insertion of the screws in local anesthesia, orthodontic forces were applied immediately. One screw worked loose and had to be removed before the end of treatment. Problems encountered included impingement of the screw head and slight inflammatory reactions of the surrounding mobile mucosa, which necessitated premature removal of two screws. After healing, a new insertion site was chosen. Further treatment was uneventful. Anchorage for orthodontic forces as described offers several advantages. The total treatment time is reduced as the screws can be loaded immediately. The line of action of the orthodontic force coincides with the level of the center of resistance of the molar resulting in a favorable translatory tooth movement. Treatment does not depend on patient cooperation.
Connective tissue orientation around dental implants in a canine model
Authors: Çomut A. Alper , Weber Hans Peter , Shortkroff Sonya , Spector Myron , Cui FuZhai
Published: March 2003

Abstract: The objective of this study was to evaluate the orientation of collagen in the canine gingival connective tissue to a titanium surface (TI), and to hydroxyapatite coatings applied by plasma‐spraying (HAPS) and ion beam assisted deposition (IBAD), on the supracrestal region of dental implants after 3 and 4 months. The effects of induced peri‐implantitis on the soft connective tissue apposed to the implant were also evaluated. The use of these three surface types allowed for the evaluation of the effects of chemical composition (TI vs. IBAD; same topography) and topography (HAPS vs. IBAD; similar chemical composition) on the collagen fiber orientation. The majority of collagen fibers were found to be parallel to the implant surface, and there was no significant effect of surface type on orientation. There was a significant effect of inflammation on the connective tissue attachment length. The loss of bone height and concomitant gingival recession reduced the length of soft connective tissue apposed to the implant zone designed for collagen fiber attachment.
Evaluation following functional loading of titanium fixtures placed in ridges augmented by deproteinized bone mineral
Authors: Skoglund Annika , Hising Peter , Attström Rolf , Mayfield Lisa J.A. , Lang Niklaus P.
Published: March 2003

Abstract: The aim of this investigation was to clinically evaluate the periimplant tissues of titanium fixtures, placed in regions augmented using deproteinized bone mineral, after initial functional loading. The original material included 18 individuals (mean age 71±9 years) treated using a graft material, Bio‐Oss® (6 Patients), or Bio‐Oss®+autogenous bone mixture (12 patients) for alveolar ridge augmentation. 6 titanium fixtures were placed at the time of ridge augmentation. 46 fixtures were placed at a second surgical stage, median 9.5 months after augmentation. Augmentation included crest width (26 fixtures), crest height and width (12 fixtures) and sinus floor lift (14 fixtures) procedures. In addition, 16 fixtures were placed in regions of adequate bone volume. Reconstructions were placed and patients were recalled on a yearly basis. After 4–6.5 years of functional loading, the reconstructions were removed and assessments of fixture stability and periimplant mucosal conditions were made. At this time, 3 patients (13 fixtures) were lost to follow‐up (1 deceased, 1 declined to participate, and 1 too ill to attend). In the remaining 15 patients, 7 fixtures were lost due to osseo‐disintegration, 2 in one patient in the mandible, and 5 in a second patient in the maxilla. Both individuals were smokers. The remaining 32 fixtures were clinically stable. Periimplant mucosa was healthy with a mean modified sulcular bleeding index of 0.1±0.2 and a mean probing depth of 1.5±1.1 mm. Radiographic evaluation showed alveolar bone levels at or above the level of the first fixture thread. There were no perifixtural radiolucencies. The survival rate, which coincided with success rate, for fixtures placed in conjunction with ridge augmentation using deproteinized bone mineral was 100% for non‐smokers and 43% for smokers after 4–6.5 years of functional loading. No fixture loss occurred in non‐augmented areas.
Marginal bone reaction to oral implants: a prospective comparative study of Astra Tech and Brånemark System implants
Authors: Åstrand Per , Feldmann Hartmut , Engquist Bo , Dahlgren Simon , Engquist Eva , Gröndahl Kerstin
Published: March 2003

Abstract: In earlier studies of Astra Tech and Brånemark System implants, high survival rates and small marginal bone changes have been demonstrated. The aim of this study was to compare the two systems, primarily with regard to marginal bone changes, but also with regard to other clinical variables of interest. The present paper describes the results after three years. Sixty‐six patients were included in the study and randomly assigned to treatment with Astra Tech implants (n=184) or Brånemark System implants (n=187). The marginal bone level was radiographically examined at fixture insertion, at abutment connection, at baseline (delivery of the prosthetic construction) and at 1‐ and 3‐year follow‐up examinations. Between fixture insertion and the baseline examination, the pattern of marginal bone resorption differed between the two systems. However, there was no significant marginal bone change between baseline and the 1‐year examination or between the 1‐ and 3‐year examinations. Nor were there any differences between the systems. The mean bone loss in the upper jaw between BL (baseline) and 3 years was 0.2±0.3 mm for Astra Tech implants and 0.2±0.1 mm for Brånemark System implants. The corresponding figures for the lower jaw were 0.3±0.2 mm and 0.2±0.1 mm. The survival rate of Astra Tech implants was significantly higher (98.9%) than for Brånemark System implants (95.2%). However, five of the nine implant losses in the Brånemark group occurred in one patient. For that reason, this result must be interpreted with caution. The number of patients with implant losses did not differ significantly between the systems. Few complications were recorded up to 3 years.
Expression of bone morphogenetic protein in the course of osteoinduction by recombinant human bone morphogenetic protein‐2
Authors: Okubo Yasunori , Bessho Kazuhisa , Fujimura Kazuma , Iizuka Tadahiko , Kusumoto Kenji , Ogawa Yutaka
Published: March 2003

Abstract: To clarify the mechanism of osteoinduction by recombinant human bone morphogenetic protein‐2 (rhBMP‐2), we examined the time‐course localization of bone morphogenetic proteins (BMPs) immunostained by an anti‐BMP‐2 monoclonal antibody after implantation of pellets consisting of rhBMP‐2 and collagen in rat calf muscle pouch. On day 3 after implantation, BMP was detected in the entire lump, and the intensity of staining for BMP around the implant on day 7 was weaker than that on day 3. The staining for BMP decreased with time and the region of staining for BMP remained more centralized in the implant. On day 10 after implantation, BMP was observed in part of the newly induced cartilage, especially around chondrocytes. On day 14 after implantation, BMP was localized in the newly induced woven bone. On day 21, BMP staining was found in osteoblasts at the surface of the newly induced bone. Especially, the staining for BMP decreased from day 10 to day 21. These results indicate that the woven bone was replaced with mature lamellar bone from day 14 to day 21. The present findings suggest that rhBMP‐2 plays an important role in osteoinduction, especially at the early stage.
Alveolar ridge augmentation using a resorbable copolymer membrane and autogenous bone grafts
Authors: Donos Nikolaos , Kostopoulos Lambros , Karring Thorkild
Published: March 2003

Abstract: The aim of the present study was to compare the result of maxillary alveolar ridge augmentation by the combined use of mandibular bone grafts and resorbable membranes (Resolut®), with that achieved by the use of the same type of bone graft combined with the placement of e‐PTFE membranes (Gore‐Tex®). The experiment was carried out in 30 rats. In one side of the maxillary jaw, the edentulous alveolar ridge between the incisor and the first molar was augmented by means of an autogenous mandibular bone graft that was fixed with a titanium microimplant and covered with a resorbable membrane. The contralateral side, serving as control, was treated in the same way, with the difference that an e‐PTFE membrane was placed over the bone graft. Histological analysis at 15, 30, 60, 120 and 180 days after surgery demonstrated that, in both test and control sites where the membrane was properly adapted and not exposed, the bone grafts presented no resorption and were integrated into the maxillary bone at the recipient site. In cases where the membrane was exposed, however, the bone grafts presented extensive resorption and lack of continuity between the graft and the recipient bed. At 60–180 days after surgery, the exposure of both types of membrane had frequently led to complete resorption of the grafts, encapsulation of the titanium microimplant by fibrous connective tissue, or exfoliation of the microimplant. It is concluded that alveolar ridge augmentation can be predictably accomplished by combining mandibular bone grafting with the placement of resorbable or non‐resorbable membranes according to the GTR principle, provided that the membrane is properly adapted over the graft and complete closure of the treated area is maintained during healing.
Maxillary sinus augmentation model in rabbits: effect of occluded nasal ostium on new bone formation
Authors: Asai Sumito , Shimizu Yoshinaka , Ooya Kiyoshi
Published: March 2003

Abstract:This study was undertaken to establish an experimental model for maxillary sinus augmentation in rabbits and to clarify the bone response to the occluded nasal ostium. In rabbits without ostial occlusion, the elevation of the sinus mucosa resulted in formation of a subantral hollow space filled with blood clots and granulation tissue 1 week after operation. The newly formed bone filled in the space had a central granulation tissue. The space was almost completely replaced by a normal sinus airspace after 3 weeks. In rabbits with ostial occlusion, a fully formed bone mass was seen after 3 weeks. The mass had both mature trabeculae and peripheral cortical bone containing no sinus airspace after 6 weeks. This animal model for maxillary sinus augmentation may improve our understanding of the bone formation procedure in humans and delineate how sinus air pressure caused by the occluded nasal ostium affects the quantity and fate of newly formed bone.
Morphofunctional and clinical study on mandibular alveolar distraction osteogenesis
Authors: Zaffe Davide , Bertoldi Carlo , Palumbo Carla , Consolo Ugo
Published: March 2003

Abstract: Alveolar Distraction Osteogenesis (ADO) is a process which forms new alveolar bone to correct alveolar deformities in ridge height and width. This work aims (a) to verify the predictability of the augmentation of height of atrophic alveolar ridges using an extra‐alveolar distraction device and (b) to study the bone processes in order to optimize implanto‐prosthetic rehabilitation. ADO was performed on 10 patients with ridge deformities to obtain the required ridge augmentation. Clinical and radiological (OPT and CT with densitometric assay) evaluations were carried out during the following 12 weeks, before implant insertion. Biopsies at 40, 60 and 88 days were studied after general, specific and histochemical staining of slides; microradiographs were analyzed to evaluate the Trabecular Bone Volume. Forty days after the end of distraction, soft callus indicated the start of ossification. Sixty days after the end of distraction, the soft callus was largely converted into a network of trabecular woven bone; osteogenic activity was high and TBV was about 50%. Eighty‐eight days after the end of distraction, the amount of bone appeared reduced, with a more ordered structure; bone formation activity and TBV also diminished, whereas osteoclast erosion was active. The densitometric assay shows values increasing from the end of distraction, particularly after implant insertion. Histological results show a regression in bone deposition processes 88 days after the end of distraction culminating in a virtual steady‐state after a certain time. The results suggest that early implant insertion may be desirable to avoid bone loss due to mechanical unloading.