bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat generated during preparation of titanium implants of the ITI® Dental Implant System: an in vitro study
Authors: Brägger U. , Wermuth W. , Török E.
Published: March 2003

The aim of the present study was to assess in vitro the heat generated within the implant body when preparing titanium implants of the ITI® Dental Implant System to estimate the potential risk of tissue damage of individual abutment preparation. The speed and the pressure were applied according to routine clinical procedures used in the patient's mouth. Much attention was paid to ensure optimal cooling at the point where the implant and secondary part were being cut. For each of 3 preparations the change from the original temperature was measured over a period of 40 s. Each type of preparation was repeated on 5 implants fitted with temperature probes. Three different preparatory procedures performed with rotating diamond burs and stainless steel finishing burs under cooling with spray from the dental unit may result in a maximal increase in temperature of 10°C, 7°C and 3°C measured coronally, both at the implant shoulder and at the coronal extent of the plasma‐sprayed surface after 10 s. The use of additional spray and pressured air significantly reduced this maximal increase to 5°C 5°C and 4°C respectively at 10 s. At the 30‐s and 40‐s time points, all the measured temperatures were significantly lower. Preparation of implants or abutments does not lead to detrimental effects on peri‐implant tissues provided that adequate cooling with spray is used. However, without cooling, extreme overheating could be provoked. reaching the critical temperature that would lead to irreversible 1 bone damage within only a few seconds.
Thresholds for tactile sensitivity perceived with dental implants remain unchanged during healing phase of 3 months
Authors: Keller D. , Hämmerle C. H. F. , Lang N. P.
Published: March 2003

The aim of the present study was to determine the tactile pressure thresholds perceived with dental implants during a three‐month healing phase following implant placement (osseointegration phase). The absolute threshold of tactile perception was measured in a group of patients 1 week, 1.2 and 3 months following implant placement (ITI Dental Implant System, Straumann AG, Waldenburg, Switzerland). Contralateral and neighbouring teeth were measured at the same time. For determination of the axial forces exerted on the implants and teeth, an electronic device with semi‐conductor strain gauges was used (Hämmerle et al. 1995). The results demonstrated mean thresholds of tactile perception for the implants of 160.2g (SD 61.7 g, range 77–283g) at 1 week, 133.4g (SD 5 1.9g, range 32–239g) at 1 month, 147.9g (SD 53.5g. range 70–257g) at 2 months, and 146.9g (SD 57.4g, range 77–248g) at 3 months. Statistical analysis using Student's paired t‐test revealed no significant differences between the values over time. The control teeth exhibited mean values for tactile perception of 13.1g (SD 9.6g, range 5–47g) at 1 week, 10.2g (SD 6.4g, range 4–29g) at 1 month, 14.8g (SD 15.9g, range 2–58g) at 2 months, and 15.4g (SD 12.2g, range 3–36g) at 3 months. Again, these values did not differ significantly from each other and indicated the absence of systemic alterations in perceived pressure threshold over the observation period. The mean perceived pressure threshold was more than 10 times higher for implants than for natural teeth (P<0.001) at all observation times. It is concluded that the absolute threshold of tactile perception with dental implants during the phase of osseointegration is not affected by bone and soft tissue healing taking place during the time period.
On the influence of superstructure connection on implant preload: A methodological and clinical study
Authors: Smedberg J.‐I. , Nilner K. , Rangert B. , Svensson S. A. , Glantz P.‐O.
Published: March 2003

In a combined in vitro and in vivo study strain gauges were used to register the deformation in two terminal implant abutment cylinders, when connecting three different prosthetic appliances. The prosthetic constructions were placed on the abutments and fastened both in vitro and in vivo by using different torque sequences. Furthermore, in the in vitro situation the three medial abutments were replaced by abutments which were 100 μm shorter.

The results show that even if the prosthetic constructions were judged to have a good clinical fit, relatively large External Preloads were registered both in vitro and in vivo. No significant differences in axial force or in bending moment were found between the torque sequences in vivo. There were, however, significant differences in axial force as well as in bending moment in the in vitro experiment. When the shorter medial abutments were used in vitro, a change in the axial force of approximately 200N was registered. The results confirm that the methodological approach used in this study is valid when evaluating preloads.
Surgical correction of malpositioned implants. A case report.
Authors: Hallman Mats , Carlsson Bill
Published: March 2003

A new technique for surgical correction of malpositioned implants is described. A 64‐year‐old female got her first fixed prosthesis anchored to 6 Brånemark implants in her upper jaw, in April 1993. The implants were poorly positioned and despite great efforts to make the construction aesthetically acceptable, the patient did not approve. In order to obtain better aesthetics, it was decided to move some of the osseointegrated implants to other positions. With a trephine drill, fixtures were removed including the surrounding bone, and 2 of them were placed in new sites made with the same drill. After a healing period of 6 months, abutments were connected and a new fixed prosthesis was made. After 1 year of loading, all implants were still stable. A marginal bone resorption to the 3rd thread was found around one of the implants.
The effect of antimicrobial theram on peri‐implantitis lesions. An experimental study in the dog.
Authors: Ericsson I. , Persson L. G. , Berglundh T. , Edlund T. , Lindhe J.
Published: March 2003

The objective of the present study was to evaluate the effect of systemic antibiotics and local debridement in the treatment of experimentally induced periimplantitis lesions. 5 Labrador dogs, about 1‐year old, were included in the study. In order to establish bilateral recipient sites for implants the mandibular right and left 1st molars, 4th and 3rd premolars were removed. 6 titanium fixtures (Brånemark System® Nobelpharma AB, Göteborg, Sweden) were installed and standard abutments were connected 3 months after fixture installation. Cotton floss ligatures were placed in a submarginal position around the neck of the abutments and the animals were placed on a diet which allowed plaque accumulation. After 68 weeks, when the tissue destruction amounted to about 20% of the fixture length, the ligatures were removed. 1 month after ligature removal, an antibiotic regimen (amoxicillin and metronidazole) was initiated and maintained for 3 weeks. In the left side of the mandible, buccal and lingual mucoperiosteal flaps were elevated, the granulation tissue within the bone craters adjacent to the implants was curetted, and the abutments were removed. The exposed outer surface, the internal part of the fixtures, as well as the abutments were treated with a detergent, delmopinol. The cleaned abutments were autoclaved, and connected to the cleaned fixtures. The mucoperiosteal flaps were replaced to their original position, adapted to the abutments and sutured. A careful plaque control program was initiated for the left jaw quadrants. In the right side of the mandible no local treatment was given to the fixtures and the abutments following ligature removal. Furthermore, no plaque control was provided to the implant segments in the right jaws. After 4 months of healing block biopsies including one implant with adjacent hard and soft tissue were harvested and prepared for light microscopy. It was observed that systemic antimicrobial therapy, combined with implant cleaning, curettage of the bone defect and regular plaque control resulted in (i) resolution of the peri‐implantitis lesion, (ii) a significant recession of the marginal peri‐implant mucosa: and (iii) a minor additional apical shift of the base of the bone defect. In the untreated sites the plaque associated infiltrate remained and was in several sites examined in contact with the adjacent bone tissue.
Guided bone regeneration in the treatment of peri‐implantitis
Authors: Persson L. G. , Ericsson I. , Berglundh T. , Lindhe J.
Published: March 2003

The objective of the present experiment was to study the soft and hard tissure healing following treatment of experimentally induced peri‐implantitis. 5 labrador dogs about 1‐year old were used. The mandibular right and left 1st molars, 4th and 3rd premolars were removed, titanium fixtures (Brånemark System®) were installed, and standard abutements were connected in a 2nd stage procedure. After 3 months experimental peri‐implantitis was induced by the placement of cotton floss ligatures in a submarginal position. 6 weeks later the ligatures were removed. 1 month after ligature removal, an antibiotic regimen was initiated. During a 3‐week period, each dog was given tablets of amoxicillin and metronidazole. In the left side of the mandible, buccal and lingual mucoperiosteal flaps were elevated and granilation tissure within the bone craters curetted. The abutments were removed. The exposed outer surface and the internal part of the fixtures were carefully cleaned with a detergent (delmopinol HC1). An e‐PTFE membrane was placed over each fixture and adjusted to cover the bone crater. New cover screws were fitted through the membranes to the cleaned fixtures. The implants were submerged and the flaps sutured. In the right side of the mandible no local treatment was performed. The dogs were sacrificed after 4 months and biopsies prepared for histological examination. The findings indicated that treatment of a peri‐implantitis lesion, including comprehensive systemic antimicrobial therapy and cleaning of submerged implants resulted in (i) the elimination of the inflammatory process in the peri‐implantitis tissues and (ii) the establishment of a dense connective tissue capsule in direct contact with the previously exposed surface of the implant system. It was also observed that (iii) new bone was frequently laid down on the pristine cover screws.
A prospective study of Astra single tooth implants
Authors: Palmer R. M. , Smith B. J. , Palmer P. J. , Floyd P. D.
Published: March 2003

A new design of single tooth implant (AstraTech, Mölndal Sweden) featuring a microthreaded conical neck and TiO blasttm surface was evaluated clinically and radiographically after 2 years in function. Fifteen patients (age range 16 to 48) with missing maxillary anterior teeth (6 central incisors, 8 laterals, 1 bicuspid) had 4,13 mm and 11,15 mm implants placed under local anaesthesia and left for a period of 6 months before exposure and abutment connection/crown fabrication. All patients were seen at 4 to 6 monthly intervals for hygienist maintenance. Radiographs using Rinn holders and a long cone technique were taken at the crown insertion and after 1 year (14 subjects) and 2 years (12 subjects). All implants were successfully integrated at stage 2, and no implants have been lost. The internal conical seal design of the abutment/implant interface facilitated connection and there were no cases of abutment screw loosening. No soft tissue problems were observed, and the gingival morphology/health was well maintained. One crown was recemented after 18 months in function, and 1 crown was replaced because of a fracture to the porcelain incisal edge. At crown insertion, the mean bone level was 0.46 to 0.48 mm apical to the top of the implant and there were no statistically significant changes in the bone level over the 2 years of the study. In conclusion, the single tooth Astra implants were highly successful and bone changes within the first 2 years of function were comparable with other systems reporting high long‐term success rates.
The significance of angiogenesis in guided bone regeneration. A case report of a rabbit experiment.
Authors: Schmid Jürg , Wallkamm Beat , Hämmerle Christoph H. F. , Gogolewski Sylwester , Lang Niklaus P.
Published: March 2003

A dome‐shaped bioresorbable membrane was fixed to the wounded rabbit calvaria and filled with a bioresorbable fibre conglomerate. After 4 weeks, the histologic preparation revealed an intimate spatial and temporal correlation between newly formed blood vessels and de novo extraskeletal bone formation. These observations emnhasize the sipnificance of angiogenesis in guided bone generation.
Elimination of bacteria on different implant surfaces through photosensitization and soft laser. An in vitro study.
Authors: Haas Robert , Dörtbudak Orhun , Mensdorff‐pouilly Nikoletta , Mailath Georg
Published: March 2003

Microbiologic examinations of implants have shown that certain micro‐organisms described as periodontal pathogens may have an influence on the development and the progression of peri‐implant disease. This experimental study aimed to examine the bactericidal effect of irradiation with a soft laser on bacteria associated with peri‐implantitis following exposure to a photo‐sensitizing substance. Platelets made of commercially pure titanium, either with a machined surface or with a hydroxyapatite or plasma‐flame‐sprayed surface or with a corundum‐blasted and etched surface, were incubated with a pure suspension of Actinobacillus actinomyetemcomitans or Porphyromonas gingivalis or Prevotella intermedia. The surfaces were then treated with a toluidine blue solution and irradiated with a diode soft laser with a wave length of 905 nm for 1 min. None of the smears obtained from the thus treated surfaces showed bacterial growth, whereas the smears obtained from surfaces that had been subjected to only one type of treatment showed unchanged growth of every target organism tested (P<0.0006). Electron microscopic inspection of the thus treated platelets revealed that combined dye/laser treatment resulted in the destruction of bacterial cells. The present in vitro results indicate that lethal photosensitization may be of use for treatment of peri‐implantitis.
Measurements of bone and frame‐work deformations induced by misfit of implant superstructures. A pilot study in rabbits.
Authors: Jemt Torsten , Lekholm Ulf
Published: March 2003

This in viva study used a 3‐D photogrammetric technique to measure distortion of 3 unit implant frame‐works and bone surrounding osseointegrated implants after securing misfitting superstructures to the implants. Four adult loop‐eared rabbits were provided with 3 implants each in the proximal part of 1 tibia each. After a healing period of 8 weeks, a titanium frame‐work was connected with a misfit to the central implant. Three‐dimensional photographs were taken before and after securing the central screw, which induced a calculated mean preload of 246 N. Measurements and comparisons of the topography of the frame‐works and surrounding bone before and after tightening the central screw indicated a complex and inconsistent deformation pattern. Generally, it could be observed that the top edge of the central cylinder showed vertical movement towards the bone of about 150 μm, always in combination with a rotation of the entire super‐structure. The head of the central implant seemed to show a corresponding displacement towards the frame‐work of about 50 to 200 μm. Bone deformation was found to be basically localized between the implants, where compressions of about half a millimetre were observed. This concentration of bone deformation as a result of misfit may be one contributing factor to initial marginal bone loss, occasionally observed after insertion of implant supported prostheses.
Clinical and radiographic evaluation, following delivery of fixed reconstructions, at GBR treated titanium fixtures
Authors: Mayfield Lisa , Skoglund Annika , Nobréus Nils , Attström Rolf
Published: March 2003

Conditions following incorporation of fixed reconstructions, at endosseous titanium implants augmented at local bony dehiscence and fenestration defects using a bioabsorbable Resolut® membrane were studied in 7 patients. Fixture stability, radiographic marginal bone levels and peri‐implant soft tissue status were evaluated at 2 1 membrane treated and 17 control fixtures (installed in regions of adequate bone volume), following a 2‐year period of functional loading. Prosthetic reconstructions were removed and clinical examination and Periotest values revealed that all fixtures were stable. All peri‐implant soft tissues were clinically healthy. The mean probing depths at buccal sites for fixtures with original dehiscence (n=10) and fenestration (n=11) defects were 1.6 ± 0.7 mm and 1.2 ± 0.4 mm respectively. The control fixture group had a mean buccal probing depth of 1.4 ± 0.6 mm. At abutment connection radiograph membrane treated fixtures had significantly lower marginal bone levels than control fixtures, indicating that optimal bone regeneration was not achieved at all defects. Mean radiographic bone loss 23–7 months following delivery of fixed reconstructions for original dehiscence and fenestration defect fixtures was 0.7 ± 0.8 mm and 0.8 ± 0.6 mm respectively at mesial surfaces, and 0.8 ± 0.7 mm and 0.6 ± 0.5 mm at distal surfaces. In the control fixture group a mean loss of 0.7 ± 0.5 mm at mesial surfaces and 0.5 ± 0.4 mm at distal surfaces was found. Results showed no significant difference in the rate of bone loss following functional loading between membrane treated and control fixtures.
Implant supported single‐tooth replacements compared to contralateral natural teeth. Crown and soft tissue dimensions.
Authors: Chang Moontaek , Wennström Jan L. , Ödman Per , Andersson Bernt
Published: March 2003

The aim of this study was to make a comparative evaluation of crown and soft tissue dimensions between implant‐supported single‐tooth replacements and the contralateral natural tooth. Twenty patients, who had been treated with an implant‐supported single‐tooth replacement in the esthetic zone of the maxillary jaw and had i) a non‐restored contralateral natural tooth and ii( completed the implant‐supported crown restoration at least 6 months prior to the scheduled follow‐up examination, were included in the study. At the re‐examination various variables describing crown form, soft tissue dimensions and soft tissue conditions were assessed. In addition, the patient’s overall satisfaction with the esthetic out‐come of the implant‐supported single crown was scored using a Visual Analogue Scale (VAS). In 12 of the subjects clinical photographs were available from the time of crown insertion for evaluation of longitudinal alterations of the papilla height. The results revealed that, in comparison to the contralateral natural crown, the implant supported crown i) was longer, ii) had a smaller facio‐lingual width, iii) was bordered by a thicker facial mucosa, iv) had a lower height of the distal papilla, v) showed a higher frequency of mucositis and bleeding on probing and vi) showed greater probing depths. The longitudinal evaluation of the papillae adjacent to the implant crown showed an improved proximal soft tissue fill at the follow‐up examination. The VAS scoring of the patients' satisfaction with the appearance of their single implant‐supported restorations revealed a median value of 96% with a range from 70 to 100%. Hence, observed differences in clinical crown height and soft tissue topography between implant‐supported single‐tooth replacements and the contralateral natural tooth may in most patients be of minor importance for the appreciation of the esthetic outcome of implant therapy.
Chemical treatment of machined titanium surfaces. An in vitro study.
Authors: Krozer Anatol , Hall Jan , Ericsson Lngvar
Published: March 2003

Microbial plaque accumulation on titanium dental implant surfaces can result in an inflammatory condition of the surrounding tissues. Cleaning of such a contaminated surface, in viva, by means of a solution of amino‐alcohol, following surgical exposure, has been proposed. However, the tissue healing following treatment resulted in formation of a fibrous capsule at the tissue‐implant interface, i.e. improper implant re‐integration.The present experiment was designed to investigate the possible influence of an amino‐alcohol solution on machined titanium surface properties. Titanium samples with topography and chemical composition similar to the clinically used Brinemark implant surfaces were used in this experimental in‐vitro study to investigate the adsorption of amino‐alcohol to such surfaces, and the possibilities to chemically remove the adsorbed alcohols in order to recover a pristine titanium surface. The amino‐alcohol solution was supplied to the samule surfaces and four different methods were subseque& used in order‐to remove the adsorbed alcohol molecules. It was shown that rinsing in water, saline solution and 5% H2O2 did not remove the amino2alcohol from the surface. Howewer, exposure to ozone produced by using a commercial mercury lamp in ambient air resulted in complete removal of the adsorbed amino‐alcohol The results show that the amino‐alcohol used forms a stable and dense film at the implant surface in vitro. Presence of such a film most likely prevents re‐integration to occur at the implant tissue interface in viva.
Rotated palatal flap in immediate implant procedures
Authors: Nemcovsky Carlos E. , Artzi Zvi , Moses Ofer
Published: March 2003

Immediate implant placement after tooth extraction is a successful treatment modality. Primary flap closure is important for satisfactory final results in these procedures. The purpose of this article was to evaluate a surgical approach that would enable predictable primary soft tissue closure over implants placed into fresh extraction sockets. In 24 patients, 26 consecutive implants were placed immediately following extraction of one anterior or premolar maxillary tooth. Primary closure was achieved by a surgical technique based on a rotated palatal flap (RPF), covering the implant. Deproteinized bovine bone was used as grafting material. The apicocoronal distance between the buccal alveolar crestal bone and the coronal aspect of the implant body was measured at time of implant placement (mean 2.6 mm, SD 1.72) and at second stage surgery (mean 0.6 mm, SD 0.70). The difference between both records was calculated. The mean gain in crestal bone was 2.0 mm (SD 1.69, P<0.001). In 1 patient, where the implant cover screw became exposed early, crestal bone loss was noted. This technique offers a predictable valuable treatment approach to achieve and maintain primary soft tissue coverage and crestal bone regeneration over implants immediately placed within a bony envelope, after extracting maxillary teeth, without the use of barrier membranes.
Effectiveness of three treatment modalities for the edentulous mandible
Authors: Raghoebar Gerry M. , Meijer Henny J. A. , Stegenga Boudewijn , Van't Hof Martin A. , Van Oort Rob P. , Vissink Arjan
Published: March 2003

Currently, 3 treatment options are available for patients with denture complaints and an edentulous mandible with a height of at least 15 mm: meticulous construction of a new set of dentures (CD), construction of a new set of dentures following preprosthetic surgery to enlarge the denture‐bearing area (PPS), and construction of an implant‐retained mandibular overdenture (IRO). The aim of this study was to evaluate patient satisfaction and subjective chewing ability of edentulous patients treated with one of these treatment modalities. Ninety edentulous patients (Cawood class IV and V, mean mandibular height 20.7 mm) were randomly assigned to receive 1 of these 3 groups. Denture satisfaction and chewing ability were assessed using questionnaires focusing on denture‐related complaints and problems chewing different types of food were assessed before treatment, and 1‐ and 5‐years after treatment. At the 1‐year evaluation, significantly better scores were observed in the 2 surgical groups (IRO, PPS) than in the CD group. At 5‐year evaluation the “complaints of the lower denture” showed a significantly better score in the IRO group when compared to the PPS and CD groups. No significant differences were observed between the PPS and CD group. From this study it is concluded that both in the short and long term denture satisfaction appears most favourable in the IRO group when compared to the PPS and CD groups. Implant‐retained overdentures are therefore a satisfactory treatment modality for edentulous patients with problems with their lower denture, even in cases of not severely resorbed mandibles.
The clinical use of deproteinized bovine bone mineral on bone regeneration in conjunction with immediate implant installation
Authors: Van Steenberghe Daniel , Callens Ann , Geers Lut , Jacobs Reinhilde
Published: March 2003

Twenty‐one c.p. titanium screw‐shaped implants were immediately installed after extraction and thorough curettage of the alveoli in 15 patients. Granules of deproteinized bovine bone of 0.25–1.0 mm diameter were used to fill the remaining defect when the distance of the defect wall to the implant surface was >3 mm. Dimensional measurements of the defect height and width were made with a pocket probe. Fourteen sites in the upper jaw and 7 sites in the lower jaw were thus treated. The mean defect depth varied between 7 mm vestibularly and 10 mm mesially. The mucoperiosteal flaps were hermetically closed. At re‐entry, the particles were packed and firmly attached but still distinguishable from the surrounding bone. Of the 21 sites treated, 5 sites had an exposure of the implant cover screw during the healing period. An exposure of the granular material occurred in 4 sites, but loss of granules in only 3. Even in these sites no signs of infection or inflammation of the soft tissues were observed. At re‐entry after 6 months, 10 sites were completely and 9 partially filled. For the partial fills, the mean remaining defect height was 1.6 mm (range: 0.6–3.0 mm). Two sites showed an increased defect of respectively 2.4 and 4.8 mm. No fixtures were lost. The present results indicate that deproteinized bovine bone is a safe filling material to fill remaining defects around implants installed in fresh extraction sockets.
Bone augmentation by onlay implant using recombinant human BMP‐2 and collagen on adult rat skull without periosteum
Authors: Murata Masaru , Maki Fumiyo , Sato Daisuke , Shibata Toshiyuki , Arisue Makoto
Published: March 2003

The purpose of this study was to determine whether bone augmentation could be obtained by the composite of recombinant human bone morphogenetic protein‐2 (rhBMP‐2) and bioabsorbable atelocollagen when the periosteum was resected, and to compare the efficacy of the rhBMP‐2/collagen implant and the collagen alone implant. The onlay implant was inserted into the space between the elevated galea aponeurotica and the skull without the periosteum of 10‐month‐old rats. The rhBMP‐2/collagen implant resulted in osteoblasts differentiation under the galea at 1 week and active bone formation without a prior formation of cartilage. At 4 weeks, the bony trabeculae were interconnected and connected directly with the compact bone of the skull. Histomorphometric analysis at 4 weeks demonstrated that the rhBMP‐2/collagen implant showed 92.5% in the volume of bone tissue, whereas the collagen alone showed 0%. The implanted collagen was gradually replaced by bone tissue in the presence of rhBMP‐2. Our present results indicate that rhBMP‐2 stimulates undifferentiated mesenchymal cells in the galea overlying the implant to proliferate and differentiate directly into osteoblasts on the carrier collagen fibers. The collagen matrix was stably placed on the skull and suitable as a substitute for rhBMP‐2. The rhBMP‐2/collagen onlay implant might be clinically applicable for bone augmentation even under the condition without the periosteum.
A controlled clinical trial of implant‐retained mandibular overdentures; five‐years' results of clinical aspects and aftercare of IMZ implants and Brånemark implants
Authors: Meijer Henny J. A. , Raghoebar Gerry M. , Van 't Hof Martin A. , Visser Anita , Geertman Mariëlle E. , Van Oort Robert P.
Published: March 2003

The aim of this prospective randomized controlled clinical trial was to evaluate a set of clinical items and prosthetic aftercare of edentulous patients with a mandibular overdenture retained by 2 IMZ implants or 2 Brånemark implants during a 5‐years' period. Patients were allocated to the IMZ group (n=29) or the Brånemark group (n=32) by a computerized balancing method. In the IMZ group 4 implants were lost during the 5‐years' follow‐up (survival rate: 93%). In the Brånemark group 9 implants were lost (survival rate: 86%). All patients were re‐operated successfully. Multiple prosthetic revisions were necessary in both groups, especially the precision attachment system in the overdenture was subject to frequent fracture or loosening. From this study can be concluded that there is no difference in clinical state, radiographical state, survival rate and clinical implant performance between the IMZ implant system and the Brånemark implant system supporting an overdenture on 2 implants after 5 years of follow‐up.
Contribution of the periosteum to bone formation in guided bone regeneration
Authors: Weng Dietmar , Hürzeler Markus B. , Quiñones Carlos R. , Ohlms Angela , Caffesse Raul G.
Published: March 2003

The periosteum has been referred to as a protective barrier in the regeneration of bone defects. The objective of this study was to determine the contribution of periosteum as a natural barrier to bone formation in guided bone regeneration. Mucoperiosteal flaps were elevated bilaterally on the buccal aspect of the mandibular angle in 5 cynomolgus monkeys. Bleeding was induced by perforating the cortical bone. A hemispherical titanium mesh was fixed over the areas thus creating a void 5 mm in height between the mesh and the bone surface. On one side the mesh was covered with an ePTFE membrane (test side). The contralateral side did not receive further treatment (control side). After 4 month healing, histomorphometric analyses were used to determine the percentage of new bone in the void underneath the mesh, and the ratio between mineralized tissue and marrow spaces in new and old bone. The mean percentage of new bone tissue was 77.2±7.5% for the test sides and 68.6±8.4% for the control sides (P=0.018, t‐test). This new bone contained 80.0±3.6% mineralized tissue in the test group and 82.5±5.0% in the control group (P>0.05, t‐test). In both groups the newly formed bone exhibited significantly less mineralized tissue than the old bone (P<0.05, t‐test). It is concluded from this study that new bone formation was enhanced by the additional use of an ePTFE membrane under a periosteum‐lined mucoperiosteal flap when space maintenance was excluded as a critical factor.
Surgical procedures in partially edentulous patients with ITI implants Note
Authors: Buser Daniel , Von Arx Thomas
Published: March 2003

Today, partially edentulous patients represent the majority of patients seeking treatment with implant‐supported prostheses. This chapter presents the specific aspects of the surgical handling of partially edentulous patients with either single‐tooth gaps, extended edentulous spaces or distal extension situations. Due to differences in treatment objectives, a distinction is made between sites without esthetic priority (non‐esthetic sites) and with esthetic priority (esthetic sites). In non‐esthetic sites, the primary goal of the surgical therapy is to achieve a predictable hard and soft tissue integration of the implant to re‐establish function with the implant‐supported prosthesis. In esthetic sites, the goal of surgical therapy is to achieve successful tissue integration and to obtain esthetic soft tissue contours to re‐establish both function and esthetics. Therefore, the surgeon must have a clear understanding of the specific needs in a given situation, and must master the necessary surgical techniques concerning a correct implant placement and a correct soft tissue handling to achieve the treatment objectives. In non‐esthetic sites, a non‐submerged approach is clearly preferred, thus avoiding a second‐stage procedure for abutment connection. If a soft tissue correction is necessary to re‐establish keratinized peri‐implant mucosa, this is done at the time of implant placement with mucogingival surgery. In esthetic sites, a submerged implant placement is preferred to achieve esthetically pleasing soft tissue contours. If a soft tissue augmentation is necessary, this is done at the time of implant placement with connective tissue grafts. Thus, the second surgical procedure after 8–10 weeks of healing is reduced to a mucosaplasty like a punch biopsy, avoiding an open flap procedure. Based on favorable properties of the TPS surface, short implants (6 or 8 mm) and short healing periods of 3–4 months have been successfully utilized in partially edentulous patients in the last 14 years. The introduction of the SLA surface allows a further reduction of the healing period to 6 weeks of healing in all sites with normal bone density (class I–III). In summary, the ITI philosophy offers straightforward surgical concepts to predictably achieve the treatment objectives with the least demanding surgical protocol, reducing the related chairtime and costs for the patient and the clinician.
Management of the edentulous patient
Authors: D. Mericske‐Stern Regina , Taylor Thomas D. , Belser Urs
Published: March 2003

Being edentulous is a handicap, and the main objective of implant placement is to provide support of fixed prostheses or to stabilize complete dentures in the edentulous jaw. Clinical experience and clinical studies have demonstrated the broad application of non‐submerged ITI implants in prosthetic therapy in standard sites and in situations of advanced atrophy or substantial loss of tissue. The ITI implant was developed for universal use in partially and completely edentulous patients and for replacement of single missing teeth. The abutment system offers the choice of both removable and fixed prostheses with identical secondary parts. The present article describes the use of ITI implants for prosthodontic rehabilitation in the completely edentulous jaw. Indications and various types of fixed or removable prostheses, alternatives and variations of design are discussed. Prosthetic design is dependent on the number and location of implants, and conversely, the number of implants that can be placed will determine the choice of prosthesis. Treatment planning in general and with respect to individual anatomic‐morphologic conditions is described for the upper and lower jaw. Details of clinical procedures with ITI implants related to the specific design of prostheses are presented. Biomechanical aspects of fixation and stabilization of prostheses and aspects of occlusion to be built up complete the overview.
Biological and technical complications and failures with fixed partial dentures (FPD) on implants and teeth after four to five years of function
Authors: Brägger Urs , Aeschlimann Sabine , Bürgin Walter , Hämmerle Christoph H. F. , Lang Niklaus P.
Published: March 2003

Abstract: The aim of this study was to compare the frequency of biological and technical complications with fixed partial dentures (FPDs) on implants, teeth and as mixed tooth‐implant supported FPDs over 4 to 5 years of function. All implants belonged to the ITI® Dental Implant System. Group I‐I (implant FPD) included 33 patients with 40 FPDs, group T‐T (tooth FPDs) 40 patients with 58 FPDs, group I‐T (mixed tooth‐implant FPDs) 15 with 18 FPD. Of the bridge abutments 144 were teeth and 105 were implants. The median number of units replaced by the FPDs was 3 (range 2–14). The mean age of the patients was 55.7 years (range 23–83). Complete failures resulted in the loss of one FPD in each group. Two implants were lost due to fracture secondarily to development of a bone defect. One tooth had a vertical fracture and 1 tooth was lost due to periodontitis. Biological complications (peri‐implantitis, PPD ≥5 mm and BOP+) occurred at 9.6% (10) of the implants. This number was, however, reduced to 5% if the threshold for definition of peri‐implantitis was set at PPD ≥6 mm and BOP+. Biological complications occurred in 11.8% (17) of the abutment teeth (NS compared to implants); 2.8% (4) had secondary caries, 4.9% (7) endodontic problems and 4.1% (6) had periodontitis (PPD ≥5 mm, BOP+). Ten out of 32 patients with a general health problem indicated a biological complication, whereas 9 out of 53 patients with no general health problem had a biological complication (χ2: NS). Statistically significantly more technical complications were found in FPDs on implants (χ2, P≤0.05). The technical complications were associated with bruxism. Out of 10 bruxers 6 had a technical complication whereas 13 out of 75 non‐bruxers had such a complication (χ2≤0.01). Extensions were associated with more technical complications (13 out of 35 with extensions versus 9 out of 81 without). In conclusion, favourable clinical conditions were found at tooth and implant abutments after 4–5 years of function. Loss of FPD over 4–5 years occurred at a similar rate with mixed, implant or tooth supported reconstructions. Significantly more porcelain fractures were found in FPDs on implants. Impaired general health status was not significantly associated with more biological failures but bruxism as well as extensions were associated with more technical failures.
A comparison of hydroxylapatite coated implant retained fixed and removable mandibular prostheses over 4 to 6 years
Authors: Tinsley David , Watson Christopher J. , Russell John L.
Published: March 2003

Abstract: In a 6‐year prospective clinical study, 181 hydroxylapatite coated endosseous dental implants were placed into the anterior mandible of 48 patients. Twenty‐one patients were treated with fixed prostheses and 27 patients with an overdenture. When the implants were exposed all 181 had integrated. To date, there is 100% survival of all implants and they all retain a functioning prostheses. The initial results were very promising, in both groups the interval success was over 95% in the first 4 years of the study. However, by year 6, the interval success rates had fallen to 83% for both the fixed and removable groups. This study also compares the construction and maintenance complications for the two types of restorations. The clinical time taken, after implant exposure, to construct the prostheses was similar whether the fixed (mean of 8 visits) or removable option (mean of 7 visits) was chosen. However, the removable restoration cost less than half the price of the fixed when both technical time and implant component costs were evaluated. Maintenance for both groups was higher than expected, but patients required more appointments in the removable group both in the first year and beyond. Regarding the prostheses itself, the incidence of remakes, relines and general adjustments was higher in the removable group. This study has shown that the overdenture offers an effective and initially a more economical alternative to the fixed prostheses, in the treatment of the edentulous mandible. However, long‐term maintenance of such a prosthesis can be significant.
Lateral ridge augmentation using different bone fillers and barrier membrane application
Authors: Von Arx Thomas , Schenk Robert K. , Buser Daniel , Von Arx Thomas , Cochran David L. , Hermann Joachim S. , Hermann Joachim S.
Published: March 2003

Abstract: Lateral ridge augmentation has become a standard treatment option to enhance the bone volume of deficient recipient sites prior to implant placement. In order to avoid harvesting an autograft and thereby eliminating additional surgical procedures and risks, bone grafting materials and substitutes are alternative filler materials to be used for ridge augmentation. Before clinical recommendations can be made, such materials must be extensively studied in experimental models simulating relevant clinical situations. The present pilot study was conducted in three dogs. Different grafting procedures were evaluated for augmentation of lateral, extended (8×10×14 mm) and chronic bone defects in the mandibular alveolar ridge. Experimental sites received tricalcium phosphate (TCP) granules or demineralized freeze‐dried bone allograft (DFDBA) particles. Barrier membranes (ePTFE) were placed for graft protection. These approaches were compared to ridge augmentation using autogenous cortico‐cancellous block grafts, either with or without ePTFE‐membrane application. After a healing period of six months, the sites were analyzed histologically and histomorphometrically. Autografted sites with membrane protection showed excellent healing results with a well‐preserved ridge profile, whereas non‐protected block grafts underwent bucco‐crestal resorption, clearly limiting the treatment outcome. The tested alloplastic (TCP) and allogenic (DFDBA) filler materials presented inconsistent findings with sometimes encapsulation of particles in connective tissue, thereby reducing the crestal bone width. The present pilot study supports the use of autografts with barrier membranes for lateral ridge augmentation of extended alveolar bone defects.
Early endosseous integration enhanced by dual acid etching of titanium: a torque removal study in the rabbit
Authors: Klokkevold Perry R. , Johnson Paul , Dadgostari Soheila , Davies John E. , Caputo Angelo , Nishimura Russel D.
Published: March 2003

Abstract: Textured implant surfaces are thought to enhance endosseous integration. Torque removal forces have been used as a biomechanical measure of anchorage, or endosseous integration, in which the greater forces required to remove implants may be interpreted as an increase in the strength of bony integration. The purpose of this study was to compare the torque resistance to removal of screw‐shaped titanium implants having a dual acid‐etched surface (Osseotite®) with implants having either a machined surface, or a titanium plasma spray surface that exhibited a significantly more complex surface topography. Three custom screw‐shaped implant types – machined, dual acid‐etched (DAE), and titanium plasma sprayed (TPS) – were used in this study. Each implant surface was characterized by scanning electron microscopy and optical profilometry. One DAE implant was placed into each distal femur of eighteen adult New Zealand White rabbits along with one of the other implant types. Thus, each rabbit received two DAE implants and one each of the machined, or TPS, implants. All implants measured 3.25 mm in diameter × 4.00 mm in length without holes, grooves or slots to resist rotation. Eighteen rabbits were used for reverse torque measurements. Groups of six rabbits were sacrificed following one, two and three month healing periods. Implants were removed by reverse torque rotation with a digital torque‐measuring device. Three implants with the machined surface preparation failed to achieve endosseous integration. All other implants were anchored by bone. Mean torque values for machined, DAE and TPS implants at one, two and three months were 6.00±0.64 N‐cm, 9.07±0.67 N‐cm and 6.73±0.95 N‐cm; 21.86±1.37 N‐cm, 27.63±3.41 N‐cm and 27.40±3.89 N‐cm; and 27.48±1.61 N‐cm, 44.28±4.53 N‐cm and 59.23±3.88 N‐cm, respectively. Clearly, at the earliest time point the stability of DAE implants was comparable to that of TPS implants, while that of the machined implants was an order of magnitude lower. The TPS implants increased resistance to reverse torque removal over the three‐month period. The results of this study confirm our previous results that demonstrated enhanced bony anchorage to dual acid‐etched implants as compared to machined implants. Furthermore, the present results indicate that dual acid etching of titanium enhances early endosseous integration to a level which is comparable to that achieved by the topographically more complex TPS surfaces.
A modified technique of harvesting tibial cancellous bone and its use for sinus grafting
Authors: Jakse Norbert , Eskici Antranik , Pertl Christof , Seibert Franz‐Josef , Lorenzoni Martin
Published: March 2003

Abstract: Autogenous bone is the gold standard graft for sinus augmentation. The harvest of autogenous bone grafts from intraoral sites does often not provide sufficient bone volume and quality. A modified technique of harvesting a tibial cancellous graft is presented. With a micro‐bone saw, a bony lid is prepared at the medial condyle of the tibia. The lid stays attached to the tendinous pes anserinus. Following the harvest, the lid is repositioned accurately. This method offers some distinct advantages. A sufficient amount of biologically highly valuable cancellous bone may be harvested for sinus grafting and possibly other surgeries with bone augmentation. The procedure may be performed under local anaesthesia and does not require hospitalisation. Neither major complications nor serious postoperative morbidity were observed.
Re‐osseointegration after treatment of peri‐implantitis at different implant surfaces
Authors: Persson Leif G. , Berglundh Tord , Lindhe Jan , Sennerby Lars
Published: March 2003

Abstract: Peri‐implantitis is a condition that includes soft tissue inflammation and rapid loss of bone. Treatment of peri‐implantitis includes both antimicrobial and bone augmenting methods. The question of whether true re‐osseointegration may occur following treatment of peri‐implantitis is controversial. The aim of this study was to investigate whether the character of the implant surface was of importance for the occurrence of re‐osseointegration following treatment of peri‐implantitis. Four beagle dogs were used. The mandibular premolars were extracted. After 12 months, 3 ITI® solid screw dental implants were placed in each side of the mandible. In the left side, implants with a turned surface (Turned sites) were used, while in the right side implants with a SLA surface (SLA sites) were placed. After 3 months of healing, peri‐implantitis was induced by ligature placement and plaque accumulation. When about 50% of the initial bone support was lost, the ligatures were removed. Five weeks later, treatment was initiated. Each animal received tablets of Amoxicillin and Metronidazole for a period of 17 days. Three days after the start of the antibiotic regimen, one implant site (experimental site) in each quadrant was exposed to local therapy. Following flap elevation, the exposed titanium surface was cleaned with the use of cotton pellets soaked in saline. The implants were submerged. Six months later, biopsies were obtained. Treatment resulted in a 72% bone fill of the bone defects at Turned sites and 76% at SLA sites. The amount of re‐osseointegration was 22% at Turned sites and 84% at SLA sites. A treatment regimen that included (i) systemic administration of antibiotics combined with (ii) granulation tissue removal and implant surface cleaning resulted in resolution of peri‐implantitis and bone fill in adjacent bone defects. Further, while substantial “re‐osseointegration” occurred to an implant with a rough surface (SLA), bone growth on a previously exposed smooth surface (Turned) was minimal.