bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of subcrestal placement of the polished surface of ITI® implants on marginal soft and hard tissues
Authors: Hämmerle Christoph H. F. , Brägger Urs , Bürgin Walter , Lang Niklaus P.
Published: March 2003

In order to achieve esthetically more satisfying results, it has been proposed to place ITI implants with their border between the rough and smooth surfaces below the level of the alveolar crest, thereby obtaining a submucosally located implant shoulder following healing. The aim of the present experimental study was to clinically and radiographically evaluate the tissue response to the placement of one‐stage transmucosal implants with the border between the rough and the smooth surfaces sunk by 1mm into a subcrestal location. 11 patients underwent comprehensive dental care including the placement of 2 implants of the ITI Dental Implant SystemTM in the same quadrant (test and control). Randomly assigned control implants were placed according to the manufacturer's instructions, i.e. the border between the rough titanium plasma‐sprayed and the smooth polished surfaces precisely at the alveolar crest. At the test implants the apical border of the polished surface was placed −1mm below the alveolar crest. Probing bone levels were assessed at implant placement (baseline), 4 and 12 months later. Modified plaque and modified gingival indices were recorded at 1, 2, 3,4 and 12 months. Clinical probing depth and “attachment” levels were measured at 4 and 12 months. All parameters were assessed at 6 sites around each implant. The mean for each implant was calculated and used for analysis. The Wilcoxon matched pairs signed rank test and the Student r‐test were applied to detect differences over time and between the test and control implants. At baseline, a mean difference in probing bone level of −0.86mm (SD 0.43 mm, p<0.05) was found between test and control implants with the test implants being placed more deeply. Both test and control implants lost a significant amount of clinical bone height during the first 4 months (test 1.16mm, p<0.05: control 0.58 mm. p<0.05). However, only the test implants significantly lost clinical bone height from 4–12 months (test 1.04 mm, p<0.05; control 0.45mm, p=0.08). Overall, the test implants lost 2.26mm and the control implants 1.02mm of bone height during the first year of service. On the average, the test implants demonstrated a bone level 0.38mm lower than the controls at 12 months. Except for the modified gingival index at 4 months (mean difference 0.21, SD 0.19, p<0.05), no clinical parameters yielded significant differences between test and control implants at any time. It is concluded that in addition to the crestal bone resorption occurring at 1 implants placed under standard conditions, the bone adjacent to the polished surface of 1 more deeply placed ITI implants is also lost over time. Form a biological point of view, the placement of the border between the rough and the smooth surfaces into a subcrestal location should not be recommended.
Non‐submerged osseointegrated dental implants with ball attachments supporting overdentures in patients with mandibular alveolar ridge atrophy. A short‐term follow up.
Authors: Donatsky O. , Hillerup S.
Published: March 2003

Non‐submerged, hollow screw ITI‐Bonefit dental implants with ball attachments supporting overdentures were used as alternative treatment to combined vestibulo‐lingual‐plasty with free split‐thickness skin graft and removable dentures in 40 consecutive patients with mandibular alveolar ridge atrophy. One hundred and fifty‐six non‐submerged fixtures were installed. Ball attachments were mounted on the fixtures and implant‐supported overdentures inserted 34 months after fixture installation. The observation period after implant activation and prosthesis insertion varied from 1 to 3 years with a median observation period of 2 years. The overall success rate of individual implants was 99%(155/156). The prosthesis function rate was 100%(40/40). The 1‐year success rate of individual implants was 99%(155/156) with a prosthesis function rate of 100% 40/40. No persistent surgical, periodontic or prosthodontic complications were observed. The results indicate that non‐submerged osseointegrated ITI‐Bonefit dental implants with ball attachments supporting overdentures can be a successful alternative to combined vestibulo‐lingualplasty with free split‐thickness skin graft and removable dentures, and as successful as the use of submerged dental implants.
Sinus floor elevation and grafting with autogenous iliac crest bone
Authors: van den Bergh Johan P. A. , ten Bruggenkate Chris M. , Krekeler Gisbett , Tuinzing D. Bram
Published: March 2003

Insufficient bone height in the posterior area of the maxilla, due to expansion of the maxillary sinus and atrophic reduction of the alveolar process of the maxilla, represents a contraindication for insertion of dental implants. This anatomic problem can, in many cases, be solved by augmentation of the floor of the maxillary sinus. This surgical technique was introduced by Tatum. The so‐called top hinge door method creates a new floor of the maxillary sinus at a more cranial level. Underneath this new floor the existing space is filled with a bone graft. Implantation in the alveolar process with increased bone height allows insertion of dental implants. This sinus grafting technique was used in the present study. In total, 62 sinusfloor elevations were performed with cancellous iliac bone grafts in 42 patients. In those 62 augmented sinuses, 161 ITT screw type implants were inserted. The follow‐up was 1–6 years after implantation. In 2 cases infections occurred. One implant needed an extended integration time. No implants were lost. The ITI solid screw implant appears to be a suitable implant following sinusfloor elevation operations, due to its rough surface, its shape and the size of the thread. The sinusfloor elevation procedure with autogenous cancellous bone graft appears to be a valuable and reliable pre‐implantological procedure, provided a proper pre‐operative investigation and careful surgery are performed. This procedure allows dental implant placement with a high success rate.
Titanium implants and lateral forces. An experimental study with sheep.
Authors: Asikainen Pekka , Klemettil Esa , Vuilleminz Thierry , Sutter Franz , Rainio Vesa , Kotilainen Risto
Published: March 2003

The purpose of this study was to investigate the resistance of titanium implants to horizontal forces in a sheep model. Twenty implants were inserted into the foreheads of 5 sheep, 4 implants on each animal. After a healing period of 3 months, abutments were mounted on the implants. After a further healing period of 3 weeks, the implants were loaded with a horizontal pull of orthodontic elastics. The force varied between 250 and 350 grams. The duration of loading was 3 months. After the loading period the animals were sacrificed and the forehead bones with implants were fixed in formalin and evaluated histologically. In the histological specimens no signs of infection or bone loss were found around the implants. The results of the present study encourage the use of titanium implants also in cases where constant lateral forces are present.
Complete nose coverage to prevent airborne contamination via nostrils is unnecessary
Authors: Van Steenberghe Daniel , Yoshida Koichi , Papaioannou William , Bollen Curd M. L. , Reybrouck Gerald , Quirynen Marc
Published: March 2003

Besides an a traumatic procedure. aseptic techniques during surgery have been suggested to have a positive impact on the predictability of osseointegration. To avoid an infection of the surgical field, coverage of the face of the patient (drapes) and nose (surgical mask. drape and plastic film) were advocated in order to reduce airborne infections and to prevent a contact contamination of instruments and gloves. Such a coverage, however. increases the feeling of claustrophobia when local anaesthesia is used and can lead to hypoxemia. The aim of the present study was to investigate whether the expired air via the nostrils could contribute to the contamination of the oral surgical field. Test blood agar plates were installed for 30 min under the nose of volunteers lying on a surgical table; once with full coverage of their nostrils, as indicated above, and once without. Simultaneously, control plates were installed on a table besides the patient to measure the basic contamination from the environment. All plates were incubated both aerobically and anaerobically. The number of colony forming units (c.f.u.) recorded on test plates after aerobic and anaerobic incubation were surprisingly low. with a mean score of 2.7 and 5.0 c.f.u. for the uncovered situation, and 2.5 and 3.3 c.f.u. for the covered situation, respectively. The control plates were infected by a nearly comparable number of bacteria (means ranging from 2.2 to 3.2). These findings indicate that covering nostrils by a mask and sterile adhesive plastic film IS not essential in avoiding airborne microbial contamination. However, the use of a meshed nose guard to prevent contact with the highly contaminated nasal skin is highly recommended.
Treatment of severe peri‐implant bone loss using autogenous bone and a resorbable membrane. Case report and literature review.
Authors: Von Arx Thomas , Kurt Beat , Hardt Nicolas
Published: March 2003

Clinical case reports and animal studies have demonstrated that the principle of guided bone regeneration can be applied for surgical treatment of moderate to profound peri‐implant bone loss (peri‐implantitis). However, the degree of bone regeneration within the peri‐implant osseous defect was reported to be variable depending on different clinical factors and on the postoperative course. Most papers dealing with surgical treatment of peri‐implantitis advocate the use of a non‐resorbable ePTFE membrane for secluding the peri‐implant bone defect enabling bone regeneration. Additionally some surgeons fill the defects with allografts or alloplasts. The present case report demonstrates another surgical approach by using autogenous cancellous bone for grafting into the peri‐implant bone defect and placing a bioresorbable polylactide membrane as a matrix barrier. The successful out‐come of this modified surgical approach enabled the patient to maintain the implant for prosthetic reconstruction after early but severe bone loss.
The effect of a deproteinized bovine bone mineral on bone regeneration around titanium dental implants®
Authors: Hämmerle Christoph H. F. , Chiantella Giovanni C. , Karring Thorkild , Lang1 Niklaus P.
Published: March 2003

The aim of the present experiment was to test the effect of a deproteinized bovine bone mineral (Bio‐Ossa®) on guided bone regeneration (GBR&) in dehiscence defects around implants. The first 2 molars and all premolars were extracted on both sides of the mandibles of 3 monkeys (Macaca fuscicularis). Three months later, 2 titanium plasma‐coated cylindrical implants were placed in all quadrants of each monkey. During the surgical procedure, standardized dehiscence defects were produced buccally and lingually, measuring 2.5 mm in width and 3 mm in height. Four different experimental situations were created: 2 sites in each monkey were covered with an e‐PTFF membrane (M), 2 were filled with the graft material (DBBM), 2 were filled with the graft material and also covered with a membrane (M+DBBM), and 2 control sites were neither grafted nor covered (C). The flaps were sutured to allow for primary healing. Linear measurements of bone height and width were calculated on histological specimens obtained 6 months following surgery. In addition, values for bone density and for surface fraction of graft to new bone contact were measured. Vertical bone growth along the implant surface of 100% (SD 0%) for M+DBBM, 91% (SD 9%) for M, 52% (SD 24%) for DBBM, and 42% (SD 35%) for C was measured. The width of the regenerated bone 1.5 mm above the bottom of the original defect, i.e. at the 50% mark of the vertical extension of the defect, in relation to the width at the bottom of the defect amounted to 97% (SD 2%) for M+DBBM, 85% (SD 9%) for M, 42% (SD 41%) for DBBM, and 23% (SD 31%) for C. Assessment of bone density within the confinement of the regenerated bone resulted in an increase of 30% (SD 11%) for M+DBBM, 45% (SD 20%) for M, 33% (SD 20%) for DBBM, and 22% (SD 23%) for C. The values for graft to new bone contact within this compartment amounted to 80% (SD15%) for M+DBBM and 89% (SD 14%) for DBBM. In conclusion, Bio‐Oss® exhibited osteoconductive properties and hence can be recommended for GBR procedures in dehiscence defects with respect to vertical and horizontal growth of bone.
Bone‐to‐implant contact of orthodontic horizontal implants in humans subjected to loading
Authors: Wehrbein Heinrich , Merz Beat R. , Hämmerle Christoph H. F. , Lang Niklaus P.
Published: March 2003

Implant‐based anchorage in orthodontics is increasingly obtaining significance. In this study, implants were temporarily inserted into the mid‐palatal and the mandibular retromolar areas in humans for orthodontic anchorage. Histological analysis of the implant‐bone interface was performed following the retrieval of implants which were subjected to prolonged oblique orthodontic loading. The results of the histomorphometric evaluation indicated that all the implants serving for orthodontic anchorage were well integrated into the bone despite the prolonged application of the orthodontic loading. Hence, it may be concluded that small‐size, one‐part transmucosal implants with a self‐tapping thread and an SLA surface seemed to provide adequate anchorage for orthodontic therapy. Furthermore, the successful integration and the subsequent oblique loading of these orthodontic implants provide evidence that continuous forces in the order of magnitude of 2–6 N are compatible with the maintenance of osseointegration.
Guided bone regeneration using demineralized laminar bone sheets versus GTAM membranes in the treatment of implant‐associated defects. A clinical and histological study.
Authors: Majzoub Zeina , Cordioli Giampiero , Aramouni Philippe K. , Vigolo Paolo , Piattelli Adriano
Published: March 2003

This study was designed to compare the regenerative potential at dehisced implant sites of the resorbable demineralized laminar bone sheets and non resorbable GTAM membranes. Twenty‐six standard screw‐type fixtures showing buccal dehiscences in 7 patients were treated using the GBR principles and received either laminar bone sheets (experimental) or GTAM (control) membranes. Twelve experimental and 10 control sites were available for evaluation at second stage surgery carried out 8 months following implant placement. Height and maximum width of the dchiscence defects were measured at the time of implant insertion and at second‐stage procedure. Mean percentage of defect fill was 75.11% in the experimental dehiscences vwsus 86.70% in the control defects. A statistically significant difference in the percentage of defect fill could not be evidenced between the two treatment modalities. Complete till was observed in 25% of the experimental versus 70% of the control sites. A significant difference was found in the median Density Index with the GTAM group showing a consistency similar lo bone in a larger number of sites. Histologically, material with the same staining features of bone was evidenced inside the GTAM membranes in 3 cases while newly‐formed bone was present in all instances under the control GTAM barriers. In ihe laminar bone‐treated sites, the membrane maintained its integrity in almost all cases. Newly formed bone was found underlying the membrane in cases with a Density index of 5 with no evidence of bony tissue adhering to the laminar sheets.
Maxillary sinus augmentation using xenogenic bone substitute material Bio‐Oss® in combination with venous blood
Authors: Yildirim Murat , Spiekermann Hubertus , Biesterfeld Stefan , Edelhoff Daniel
Published: March 2003

The aim of the present study was to evaluate bone formation following maxillary sinus augmentation using bovine bone substitute material Bio‐Oss® in combination with venous blood by means of histologic and histomorphometric examination of human biopsies. This involved a total of 15 sinus floor elevation procedures being carried out on 11 patients (average age of 49.6 years) according to the technique described by Tatum (1986). The subantral sinus cavity was augmented using bovine apatite combined with venous blood. After an average healing phase of 6.8 months, trephine burrs were used to take 22 bone biopsies from the augmented sinus region. Then 38 Brånemark® implants were inserted in both the osteotomies resulting from bone sampling and in regular sites in the augmented posterior maxilla. Histomorphometric analysis of ground sections from the bone biopsies prepared according to the standard method of Donath & Breuner (1982) produced an average percentage of newly‐formed bone of 14.7% (±5.0%) and a proportion of residual xenogenic bone substitute material of 29.7% (±7.8%). Some 29.1% (±8.1%) of the surface of the Bio‐Oss® granulate was in direct contact with newly‐formed bone. Histologically, newly‐developed bone became evident, partly invaginating the particles of apatite and forming bridges in the form of trabeculae between the individual Bio‐Oss® particles. Despite the absence of osteoclastic activity, the inward growth of bone indicates slow resorption of the xenogenic bone graft material. When the implants were uncovered, after an average healing phase of 6 months, 4 of the 38 implants had become loose. Of these 4 implants, 1 had to be subsequently explanted, while the others remained as “sleeping implants” and were not included in the implants superstructure. Thus, the resulting clinical survival rate, prior to prosthetic loading, was 89.5%.
A mechanical evaluation of TiO2‐gritblasted and Ca‐P magnetron sputter coated implants placed into the trabecular bone of the goat: part 1
Authors: Vercaigne Suzy , Wolke Joop G. C. , Naert Ignace , Jansen John A.
Published: March 2003

The influence of Ca‐P magnetron sputter coated implants on the mechanical anchorage was evaluated in a goat model. Therefore, uncoated and coated screw designed commercially pure titanium TiO2‐blasted implants were inserted into the trabecular bone of the femoral condyles of 12 goats. The thicknesses of the coatings were 0.1 μm (CaP‐0.1), 1.0 μm (CaP‐1) and 4.0 μm (CaP‐4). In addition, uncoated TiO2‐blasted implants (Ti) were used as control. Evaluation of the interface strength and appearance, using torque test and scanning electron microscopy, was done at implantation periods of 6 and 12 weeks. Although, especially at 6 weeks of implantation, the Ca‐P coated implants showed higher failure torque values than the TiO2 blasted implants, the observed differences for type of implant and evaluation period were not significant (P>0.1). SEM evaluation showed that all implants with failure values of more than 100 N conducted bone growth into their screw threads. In addition, we observed that the fracture plane for the CaP‐4 implants was situated at the coating–implant interface or inside the coating. For the CaP‐1 and CaP‐0.1 the fracture line could not be determined definitely. For the Ti implants, the fracture torque testing resulted in failure at the bone–implant interface. Therefore, we conclude that all implants resulted in a good bonding strength with the surrounding bone. The sputtered Ca‐P coatings seemed to improve the initial fixation of the TiO2 blasted implants.
Effect of microgrooved poly‐l‐lactic (PLA) surfaces on proliferation, cytoskeletal organization, and mineralized matrix formation of rat bone marrow cells
Authors: Matsuzaka Kenichi , Walboomers Frank , De Ruijter Anja , Jansen John A.
Published: March 2003

Previous experiments showed that microgrooved substrate surfaces can influence the in vitro behavior of osteoblast‐like rat bone marrow (RBM) cells. Cellular morphology and matrix deposition can be directed by substrate chemistry and topography. RBM cells cultured on poly‐l‐lactic acid (PLA) exhibit increased mineralization and alkaline phosphatase activity compared to polystyrene substrates. Consequently, the purpose of the present in vitro study is to further evaluate the behavior of RBM cells on microgrooved (groove depth 0.5 to 1.5 μm, groove and ridge width 1 to 10 μm) polystyrene (PS) and PLA surfaces. Besides grooved, also smooth control surfaces were made. Our results confirmed that microtextured surfaces are capable of influencing the behavior of the osteoblast‐like RBM cells in vitro. Microtopography did not influence the RBM proliferation rate, or cellular actin organization. However, confocal laser scanning microscopy showed that cellular attachment is dependent on the applied material. Also clear differences were found between textured PS and PLA, with regard to the calcium content. We therefore conclude, that the application of microtextures could possibly influence the bone regeneration around biodegradable PLA devices.
Controlled local application of basic fibroblast growth factor (FGF‐2) accelerates the healing of GBR
Authors: Hosokawa Ryuji , Kikuzaki Kenji , Kimoto Tomohide , Matsuura Takashi , Chiba Daisuke , Wadamoto Masayoshi , Sato Yuuji , Maeda Miho , Sano Akihiko , Akagawa Yasumasa
Published: March 2003

This animal study was performed to ascertain whether the regeneration of membrane‐protected bone defects can be accelerated by the controlled application of basic fibroblast growth factor (FGF‐2) using a new drug delivery system. Standardized alveolar bone defects were made surgically in 9 beagle dogs, and FGF‐2 was administered using specially made collagen minipellets. A minipellet containing either 0.15 μg FGF‐2 (FGF) or 0 μg FGF‐2 (placebo) was placed in the defect or no minipellet was used (control), and bone regeneration was evaluated radiologically, histologically, and histometrically 8 weeks after the operation. Radiographs showed a surprisingly large radiopaque region in FGF sites compared with placebo or control sites. Histologically, mature bone filled the majority of the inner space of the membrane‐protected defect in FGF sites. New bone formation was also seen in the control and the placebo sites, however, it filled less than half the area of the defect. Histometrically, the area of regenerated bone in FGF sites was significantly higher than in the other sites (P<0.01). These results demonstrate that the controlled application of FGF‐2 accelerates bone regeneration in membrane‐protected bone defects in the canine model.
Anisotropic elastic properties of cancellous bone from a human edentulous mandible
Authors: O'Mahony Aisling M. , Williams John L. , Katz Jerald O. , Spencer Paulette
Published: March 2003

The elastic moduli have not been reported for cancellous bone from the edentulous mandible. Accurate values are needed for finite element modeling of the mandible. The aim of this study was to determine elastic modulus values in three orthogonal directions for cancellous bone taken from an edentulous jaw and to relate these values to apparent density and volume fraction. Seven samples were obtained from the edentulous mandible of a 74‐year‐old female. Young's modulus was determined by compression testing of cubes cut with the faces aligned with the anatomic axes. Bone volume fraction averaged 0.33 (SD 0.14) and apparent density averaged 0.55 g/cc (SD 0.29). Young's modulus was greatest in the mesio‐distal direction (mean 907 MPa, SD 849 MPa), followed by the bucco‐lingual (mean 511 MPa, SD 565 MPa) and infero‐superior direction (mean 114 MPa, SD 78 MPa). The infero‐superior direction was less than the bucco‐lingual (P=0.03) and mesio‐distal (P=0.002). The mesio‐distal and bucco‐lingual directions could not be shown to be different (P=0.32). This suggests a model of transverse isotropy for cancellous bone in the jaw, where the symmetry axis is along the infero‐superior (weakest) direction.
An in vitro evaluation of the strength of a 1‐piece and 2‐piece conical abutment joint in implant design
Authors: Norton Michael R.
Published: March 2003

The performance and maintenance of implant‐supported prostheses are primarily dependent upon load transmission both at the bone‐to‐implant interface and within the implant–abutment–prosthesis complex. The design of the interface between components has been shown to have a profound influence on the stability of screw joints. In this in vitro evaluation, implants utilizing an internal conical joint have demonstrated a parity in resistance to bending moments at the fixture–abutment interface, when comparing a 1‐piece abutment to a 2‐piece abutment, which is tightened via a separate abutment screw, with mean plastic bending moments of 4176 N mm and 4049 N mm respectively. The very small values for coefficient of variance measured in both systems would confirm that whilst the size of data is small it is nonetheless a reliable indication of the relative strength of these conical joint designs.
Within‐subject comparison of maxillary long‐bar implant‐retained prostheses with and without palatal coverage: patient‐based outcomes
Authors: De Albuquerque Rubens Ferreira , Lund James P. , Tang Ling , Larivée Jacinthe , De Grandmont Pierre , Gauthier Gilles , Feine Jocelyne S.
Published: March 2003

Although maxillary implant overdentures are used in oral rehabilitation, different designs have not been compared previously in clinical trials. This crossover trial was designed to measure differences in patient satisfaction with maxillary long‐bar implant overdentures with and without palatal coverage opposed by a fixed mandibular implant‐supported prosthesis. Data were also gathered on new conventional dentures and on maxillary conventional dentures opposed by mandibular fixed prostheses. Sixteen participants were selected from a population wearing conventional dentures. Fifteen received new upper and lower dentures (1 drop‐out). Four implants were placed in the maxilla and mandible (2 drop‐outs). A mandibular fixed prosthesis was inserted in 13 participants, who were then divided into 2 groups. One group (n=7) received long‐bar overdentures with palate, then long‐bar overdentures without palate. The other group (n=6) received the same treatments in the reverse order. Mastication tests and psychometric evaluations using Visual Analog Scales and Categorical Scales were performed throughout the study. General satisfaction was very high with both maxillary implant‐supported prostheses, as were ratings of almost all psychosocial and functional variables. There were no significant differences between treatments, suggesting that patients are equally satisfied with long‐bar overdentures with and without palate when these are opposed by mandibular fixed prostheses. However, the ratings given to the maxillary implant prostheses were not significantly higher than for new conventional maxillary prostheses. This suggests that maxillary implant prostheses should not be considered as a general treatment of choice in patients with good bony support for maxillary conventional prostheses.
Implant‐supported overdentures, a prevention of bone loss in edentulous mandibles?
Authors: Von Wowern Nina , Gotfredsen Klaus
Published: March 2003

Abstract: The purposes of this study were to analyse 1) the changes in the bone mineral content (BMC) in mandibles with implant‐supported overdentures when compared with the physiologic age‐related mandibular BMC loss, 2) whether the BMC changes were different in groups without or with a bar connecting the implants and 3) whether the presence of mandibular osteoporosis affects the loss of bone height around the implants. The material consisted of 22 long‐term edentulous healthy persons, 18 women and 4 men from 54 to 78 years of age with 1 Astra Tech Dental Implant in both canine regions, connected by a bar in half of the patients. BMC measurements were performed in vivo by dual‐photon scanner at baseline, just after attachment insertion, at 2‐year and 5‐year visits. Mandibular osteoporosis was estimated by comparing baseline BMC values with normal mandibular BMC values for young adults of same gender. Loss of bone height around implants was measured on periodically identical intraoral radiographs. The fixed parts of the implant‐system were stable during the trial in all patients. In conclusion: 1) the increased function after this treatment seems to cause a load‐related bone formation which minimizes the physiologic age‐related mandibular BMC loss, 2) this effect seems to be independent of attachment system and 3) mandibular osteoporosis prior to implant treatment may be a risk factor for bone loss around implants. However, this treatment can be recommended also in osteoporotic persons.
Microbial analysis of bone collected during implant surgery: a clinical and laboratory study
Authors: Young Malcolm Peter Jackson , Carter Duncan Howard , Worthington Helen , Korachi May , Drucker David Bernard
Published: March 2003

Abstract: Dental implant surgery produces bone debris which can be used to correct bone defects in the “simultaneous‐augmentation” technique. However, this debris is potentially contaminated with oral bacteria. Therefore, this study examined bone debris collected during dental implant surgery in order 1) to identify the microbial contaminants and 2) to compare the effects of two different aspiration protocols on the levels of microbial contamination. Twenty‐four partially dentate patients were randomly allocated into two equal groups and underwent bone collection using the Frios® Bone Collector during surgery to insert two endosseous dental implants. In group S (using a stringent aspiration protocol), bone collection occurred within the surgical site only. In group NS (utilizing a non‐stringent aspiration protocol), bone collection and tissue fluid control was achieved using the same suction tip. Bone samples were immediately transported for microbial analysis. Colonial and microscopic morphology, gaseous requirements and identification kits were utilized for identification of the isolated microbes. Twenty‐eight species were identified including a number associated with disease, in particular, Enterococcus faecalis and Staphylococcus epidermidis as well as the anaerobes Actinomyces odontolyticus, Eubacterium sp., Prevotella intermedia, Propionibacterium propionicum and Peptostreptococcus asaccharolyticus. In group S (stringent aspiration protocol), significantly fewer organisms were found than in group NS, the non‐stringent aspiration protocol (P=0.001). Gram‐positive cocci dominated the isolates from both groups. It is concluded that if bone debris is collected for implantation around dental implants, it should be collected with a stringent aspiration protocol (within the surgical site only) to minimize bacterial contaminants.
Evaluation of speech in patients rehabilitated with various oral implant‐supported prostheses
Authors: Jacobs R. , Van Steenberghe D. , Manders E. , Van Looy C. , Lembrechts D. , Naert I.
Published: March 2003

Abstract: In the present study, speech function was assessed in edentulous patients wearing fixed or removable dental prostheses supported or not by oral implants. A total of 138 patients participated in the present research. The experimental group (n=113) was divided in 4 subgroups. Subgroup FD/FFPi comprised 22 patients with a maxillary full denture (=FD) and a mandibular fixed full prosthesis on implants (=FFPi). Subgroup FFPi/ND consisted of 27 patients with a maxillary fixed full prosthesis on implants and a natural dentition (=ND) in the mandible. Subgroup FD/ODi included 49 patients wearing a maxillary full denture and a mandibular overdenture on 2 implants (=ODi). Subgroup FFPi/FFPi comprised 15 patients having a fixed full prosthesis on implants in both jaws. The outcome of the logopedic screening of the experimental group was compared with that of a control group of subjects having a natural dentition (ND/ND; n=25). A standard clinical procedure for evaluation of speech was carried out by a speech pathologist. Besides, specific oral and prosthetic parameters were scored in all patients. It was established that one or more pronunciation difficulties occurred in 84% of the patients of the experimental group. This was significantly more than in the control group, where half the number of subjects had some speech deficiencies. No clear influence of specific oral and prosthetic parameters could be identified. From the present results, it could be concluded that in patients rehabilitated with oral implant‐supported prostheses speech disorder is more frequently observed than in subjects with a natural dentition.
Localisation of the mandibular canal using conventional spiral tomography: a human cadaver study
Authors: Serhal C. Bou , Van Steenberghe D. , Quirynen M. , Jacobs R.
Published: March 2003

Abstract: For certain surgical procedures (e.g. placement of implants), an accurate localisation of the mandibular canal is of utmost importance to avoid injuries to the neurovascular bundle. The aim of the present study was to evaluate, on human fresh cadavers (n=6), the accuracy of conventional spiral tomography for the localisation of the mandibular canal. By means of the Cranex TOME® multifunctional unit (Orion Corporation Soredex, Helsinki, Finland), tomographic slices were taken at 3 different locations in the left posterior mandible (distal to the mental foramen). The mandibles were then sectioned at these 3 sites with a microtome. With a digital sliding calliper, the following 3 measurements were performed both on the tomograms and the bone sections at the three sites: 1) distance from the crest to mandibular canal, 2) overall bone height and 3) bone width. Overestimations of the distance to the mandibular canal (8/18) ranged from 1.05 to 0.10 mm and underestimations from 0.30 to 1.36 mm. The same number of over‐ and underestimations occurred for the bone height (1.14 to 0.14 mm and 0.15 to 1.40 mm, respectively). The bone width scored more overestimations (10/18), ranging from 1.40 to 0.12 mm, while underestimations ranged from 0.25 to 1.35 mm. From the present results, it is concluded that spiral tomography using the Cranex TOME® multifunctional X‐ray unit provides accurate information and sufficient detail for preoperative planning of implant placement in the posterior mandible.
Radioimaging of implants in rats using Tc‐99m‐MDP
Authors: McCracken Michael , Lemons Jack E. , Zinn Kurt , Thompson John A. , Feldman Dale
Published: March 2003

Abstract: Radiopharmaceutical isotopes are widely used clinically to detect tumors of osteogenic origin. One example is Technetium‐99m methylene diphosphonate (Tc‐99m‐MDP). When viewed with a gamma camera, the concentration of the isotope (increased gamma activity) indicates an area of increased bone activity. This technology provides an opportunity to measure bone growth around implants in vivo. The purpose of this study was to measure Tc‐99m‐MDP activity around titanium alloy implants placed in the tibiae of rats. Some implant sites were treated with a growth factor; other sites served as controls. The hypothesis tested was that implants placed with a growth factor would have greater associated Tc‐99m‐MDP activity. Twelve adult male Sprague‐Dawley rats were anesthetized and surgical access to the medial proximal tibiae was obtained. Titanium alloy screw implants were placed in six animals along with 65 μg of acidic fibroblast growth factor (FGF‐1); the other six animals received implants only and served as controls. After five days, rats were injected with 1500 μCi of Tc‐99m‐MDP. After 3 hours, rats were imaged with a gamma camera. The Tc‐99m‐MDP intensity associated with each implant was quantified and the means for each group were compared using ANOVA. Implants treated with FGF‐1 demonstrated significantly more Tc‐99m‐MDP activity than implants alone. This suggests that Tc‐99m‐MDP analysis may be a useful tool for determining bone growth around implants in laboratory animals in vivo.
Transforming growth factor‐β1 incorporated in calcium phosphate cement stimulates osteotransductivity in rat calvarial bone defects
Authors: Blom Erik J. , Klein‐Nulend Jenneke , Burger Elisabeth H. , Blom Erik J. , Van Waas Marinus A. J. , Yin Lei
Published: March 2003

Abstract: Bone regeneration of the alveolar crest around dental implants is an important factor in the success of implant use. Calcium phosphate cement can be used as a bone substitute and applied clinically as a paste to fill micro‐ and macroscopic bone defects. We have shown earlier that the intermixing of the recombinant human transforming growth factor‐β1 (rhTGF‐β1) in hardening calcium phosphate cement stimulated osteoblastic differentiation of rat primary bone cells in vitro. The aim of the present study was to examine whether the similar enrichment with rhTGF‐β1 affects the replacement of calcium phosphate cement by bone (osteotransduction) in calvarial critical size defects (csd) of adult rats. Two bone defects of 5 mm diameter were created bilaterally in each skull of 10 adult male rats. Both defects were filled with 53 mg of calcium phosphate cement without rhTGF‐β1 (control) at one side, and with 10 or 20 ng rhTGF‐β1 at the other side. After 8 weeks, defects with surrounding skull were analysed histologically and histomorphometrically. The addition of rhTGF‐β1 in the cement increased the amount of bone in rat skull defects. This finding coincidences with our in vitro observations, that intermixing of rhTGF‐β1 in calcium phosphate cement stimulates bone cell differentiation. Addition of rhTGF‐β1 stimulated bone formation as indicated by an increased bone volume of 50% and an increased bone/cement contact of 65%, in comparison to control defects with cement without rhTGF‐β1. In addition, rhTGF‐β1 reduced the remaining volume of cement, by 11% at 10 ng rhTGF‐β1, and by 20% at 20 ng rhTGF‐β1 in the cement. Defect closure was not affected. We conclude that the intermixing of rhTGF‐β1 in a fast‐setting calcium phosphate cement stimulates bone growth and the osteotransduction of the cement. For bone regeneration procedures around endosseous implants, calcium phosphate cement with rhTGF‐β1 might be an appropriate combination for early osseointegration and implant use.
Evaluation of accuracy of computer‐aided intraoperative positioning of endosseous oral implants in the edentulous mandible
Authors: Wanschitz Felix , Watzinger Franz , Schopper Christian , Ewers Rolf , Birkfellner Wolfgang , Figl Michael , Bergmann Helmar , Patruta Sanda , Kainberger Franz , Kettenbach Joachim
Published: March 2003

Abstract: The overall accuracy of a novel surgical computer‐aided navigation system for placement of endosseous implants was evaluated. Five dry cadaver mandibles were scanned using high resolution computed tomography (HRCT). The position of four interforaminal dental implants was planned on the computer screen and transferred to the cadaver mandibles using VISIT, a surgical navigation software developed at the Vienna General Hospital. The specimens were HRCT‐scanned again to compare the position of the implants with the preoperative plan on reformatted slices after matching of the pre‐ and postoperative data sets using the mutual information technique. The overall accuracy was 0.96±0.72 mm (range 0.0–3.5 mm). No perforation of the mandibular cortex or damage to the mandibular canal occurred. We conclude that computer‐aided implant surgery can reach a level of accuracy where further clinical developments are feasible.
Evaluation of stability of titanium and hydroxyapatite‐coated osseointegrated dental implants: a pilot study
Authors: Simunek Antonin , Vokurkova Jarmila , Kopecka Dana , Celko Martin , Mounajjed Radek , Krulichova Iva , Skrabkova Zuzana
Published: March 2003

Abstract: An endosseous implant is described as osseointegrated when it is immobile in function. Objective measures of stability testing have been described. The Periotest is a commercially available device that is used for this purpose. This study was designed to measure stability of endosseous implants placed in the mandible. Implants were placed in the mandibular canine or first premolar area to support an overdenture prosthesis. Stability was evaluated through the use of a Periotest device at the time of implant placement and following one year of functional loading. Implant designs were either a screw‐shaped titanium alloy or a hydroxyapatite‐coated cylinder. A total of 54 implants were placed, 37 were titanium screw‐shaped implants, while the remaining 17 were hydroxyapatite cylinders. Initial measurements of stability showed no difference due to implant type. Following one year of functional loading, titanium screw‐shaped implants were more stable than hydroxyapatite implants (P<0.05). The difference in implant rigidity following a period of functional loading may be an indication of a difference in osseointegration between the two implants used in this study.
The effect of titanium surface roughness on the adhesion of monocytes and their secretion of TNF‐α and PGE2
Authors: Soskolne W. Aubrey , Cohen Sarit , Shapira Lior , Sennerby Lars , Wennerberg Ann
Published: March 2003

Abstract: Dental implant surfaces are important in determining the tissue/surface interaction. One of the first cells to adhere to the implant surface is the monocyte. This study examines the effect of surface roughness on monocyte adhesion and cytokine secretion. Monocyte adherence to titanium discs of 4 different degrees of surface roughness and plastic surfaces was assayed. Blood mononuclear cells were incubated for 1.5 h in 16 mm culture wells into which titanium discs had been placed. Non‐adherent cells were washed off and the numbers of remaining adherent monocyte determined by DNA quantification. TNF‐α and PGE2 secretion in media from overnight cultures of attached monocytes stimulated with lipopolysaccharide (LPS) was quantified using ELISA and RIA, respectively. Monocyte adherence to rough titanium surfaces was greater than to turned titanium surfaces, while the lowest adherence was to the plastic surface. No significant differences in adherence to 250, 75 or 25 μm blasted surfaces could be detected. The number of adherent monocytes increased with time, with maximum adhesion after 2 h of incubation. Incubation of monocytes adherent to titanium surfaces resulted in a decrease of less than 30% in their numbers over 7 days, whereas cells attached to plastic surfaces decreased to non‐detectable numbers after 48 h. Porphyromonas gingivalis LPS stimulation upregulated TNF‐α and PGE2 secretion into the media. The LPS‐induced TNF‐α and PGE2 secretion was independent of the titanium surface roughness, however the lowest amounts of TNF‐α and PGE2 were secreted from cells attached to plastic surfaces. The results of this study indicate that the number of monocytes attached to blasted titanium surfaces is significantly greater than to machined titanium surfaces. PGE2 and TNF‐α secretion is less influenced by titanium surface roughness.
Clinical results of alveolar ridge augmentation with mandibular block bone grafts in partially edentulous patients prior to implant placement
Authors: Cordaro Luca , Amadè David Sarzi , Cordaro Massimo
Published: March 2003

Abstract: A group of 15 partially edentulous patients who needed alveolar ridge augmentation for implant placement, were consecutively treated using a two‐stage technique in an outpatient environment. A total of 18 alveolar segments were grafted. During the first operation bone blocks harvested from the mandibular ramus or symphysis were placed as lateral or vertical onlay grafts and fixed with titanium osteosynthesis screws after exposure of the deficient alveolar ridge. After 6 months of healing the flap was re‐opened, the screws were removed and the implants placed. Twelve months after the first operation implant‐supported fixed bridges could be provided to the patients. Mean lateral augmentation obtained at the time of bone grafting was 6.5±0.33 mm, that reduced during healing because of graft resorption to a mean of 5.0±0.23 mm. Mean vertical augmentation obtained in the 9 sites where it was needed was 3.4±0.66 mm at bone grafting and 2.2±0.66 mm at implant placement. Mean lateral and vertical augmentation decreased by 23.5% and 42%, respectively, during bone graft healing (before implant insertion). Mandibular sites showed a larger amount of bone graft resorption than maxillary sites. All the 40 implants placed were integrated at the abutment connection and after prosthetic loading (mean follow‐up was 12 months). No major complications were recorded at donor or recipient sites. Soft tissue healing was uneventful, and pain and swelling were comparable to usual dentoalveolar procedures. A visible ecchymosis was present for 4 to 7 days when the bone was harvested from the mandibular symphysis. From a clinical point of view this procedure appears to be simple, safe and effective for treating localised alveolar ridge defects in partially edentulous patients.
A multicenter prospective evaluation of 2‐months loaded Osseotite® implants placed in the posterior jaws: 3‐year follow‐up results
Authors: Testori Tiziano , Del Fabbro Massimo , Bianchi Francesca , Francetti Luca , Weinstein Roberto L. , Feldman Sylvan , Vincenzi Gianpaolo , Sullivan Daniel , Rossi Renato , Anitua Eduardo
Published: March 2003

Abstract: In this prospective study, the clinical outcome of 2‐months loaded implants placed in the posterior jaws was evaluated after up to 3 years of functional loading. 405 Osseotite® implants with microtextured acid‐etched surface were consecutively placed in 11 fully and 164 partially edentulous patients (mean age 53.5± 15.3 (S.D.) years) using a one‐stage technique. 282 implants, supporting 154 restorations, were placed in the mandible, while 123 implants, supporting 75 restorations, were placed in the maxilla. A total of 99 single‐tooth restorations, 119 short‐span fixed bridges and 11 full‐arch prostheses were applied. The mean time interval from surgery to connection of provisional restoration was 2.0±0.7 months. 9 failures were reported up to 3 years of follow‐up; of these, 4 mandibular and 2 maxillary implants failed during the initial healing period (before prosthesis connection), while 3 mandibular implants failed after loading. No other complications occurred throughout the study. Life table analysis showed a cumulative survival rate of 97.5% for the mandible and 98.4% for the maxilla. Post‐loading implant survival rate was 98.9% for the mandible and 100% for the maxilla. The excellent outcome of this interim report suggests that microtextured Osseotite® implants in the posterior jaws may safely bear a functional load applied 2 months after insertion. The results of the present study are particularly encouraging for implants placed in the maxilla, since both a significant reduction of the healing period compared to the 6 months suggested by the classical Brånemark protocol, and an excellent post‐loading function may be achieved also in low quality bone.