Pages 427, Language: English
Pages 435-442, Language: English
To characterize titanium surfaces treated with radio-frequency glow discharge (RFGD) after media exposure, surface chemical analyses were performed using x-ray photoelectron spectroscopy, Auger electron spectroscopy, and Fourier transform infrared-reflection absorption spectroscopy (FTIR-RAS). The RFGD treatments resulted in a cleaner surface as compared to as-sputtered or as-autoclaved titanium specimens. The oxide thickness of RFGD-treated titanium specimens was not statistically different from the as-autoclaved and as-sputter cleaned titanium specimens. Exposure to a phosphate-buffered saline solution revealed a greater deposition of calcium and phosphorous on the RFGD-treated surfaces. Auger electron spectroscopy depth profiles showed that calcium and phosphorous ions diffused into the titanium oxide layer. The calcium and phosphorous deposits were identified as amorphous calcium phosphate compounds using FTIR-RAS. These results suggest that RFGD treatments of titanium enhance calcium and/or phosphate affinity because of an increase in elemental interactions at the surface, thereby resulting in the formation of amorphous calcium phosphate compounds.
Keywords: Auger electron spectroscopy, autoclave, Fourier transform infrared spectroscopy, glow discharge, surface characterization, x-ray spectroscopy
Pages 443-449, Language: English
The goal of this study was to characterize salivary components of titanium pellicles and to determine how experimental pellicles affect adhesion of several strains of streptococci to titanium surfaces. Titanium experimental pellicles were formed by incubation of fresh human parotid or human submandibular-sublingual saliva on pure titanium beads. Pellicle was recovered from the beads using sodium dodecyl sulfate buffer and was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting to identify adsorbed salivary components. Streptococcus anginosus, S. oralis, and S. salivarius recovered from in vivo titanium plaque and five reference strains of streptococci were used in adhesion assays to titanium beads with and without experimental salivary pellicles. The experimental pellicle formed on titanium was found to be composed of selected proteins from human parotid and human submandibular-sublingual saliva. Salivary α-amylase and proline-rich proteins were found in all experimental pellicles, while sIgA, high-molecular weight mucin, and proline-rich glycoproteins were detected in one of the experimental pellicles examined. Adhesion of fresh isolates and reference stains of S. anginosus, S. oralis, and S. salivarius to saliva-coated titanium was reduced compared to that of titanium without saliva coating. However, adhesion of laboratory strains of S. gordonii and S. sanguis was found to be significantly greater to experimental pellicles of human submandibular-sublingual saliva than was the adhesion of the fresh isolates, suggesting that streptococci-colonizing implant surfaces may be inherently less adhesive than other bacterial strains. This study found that salivary pellicles are selectively formed on titanium and mediate in vitro adhesion of streptococci.
Keywords: microbial adhesion, pellicle, streptococci, titanium implant
Pages 450-455, Language: English
One hundred seven Brånemark implants were placed in 92 patients participating in an international multicenter trial on single-implant restorations at seven centers. The patients were followed for 5 years in a prospective study focusing on implant success and crown function. Plaque and gingival indexes, as well as probing depths, were recorded around teeth and implants. The marginal bone level at implants was determined from intraoral radiographs. Only three implants (2.8%) had been lost at the first annual checkup. During the follow-up period, a total of 17 patients dropped out or were excluded because of nonconformity with the protocol. Based on the remaining patients, a total of 86 implants were clinically and radiographically evaluated at the 5-year follow-up period, resulting in a cumulative success rate of 96.6% (71 implants) in the maxillae and 100% (15 implants) in the mandibles. Plaque and gingival indexes showed a similar pattern of good health around both natural teeth and titanium abutments. The marginal bone loss during the 5-year period did not exceed 1 mm as a mean for all implants analyzed. The most frequent complication recorded during the follow-up was loosening of the abutment fixation screw. The outcome of this study indicated that safe and highly predictable results can be obtained for 5 years when Brånemark implants are used to support single-tooth restorations.
Keywords: Brånemark System, multicenter investigation, single tooth implant restorations
Pages 456-465, Language: English
Bone formation at implant surfaces may be directly influenced by effects of the implant material on osteoblast behavior. Cell culture models of osteoblast physiology may be used to investigate the interaction of osteoblastic cells with various surfaces. In this study, primary cultured fetal bovine mandibular osteoblastic cells were cultured on titanium, ceramic hydroxyapatite, and glass coverslip surfaces to allow for the comparison of the mineralizing matrix elaborated by osteoblasts grown on different implant material surfaces. Morphologic and immunohistochemical analysis revealed the similar formation of multilayered, mineralizing cultures on these three surfaces. The qualitative similarity of the matrix formed on these culture surfaces may reflect similar qualitative in vivo responses of bone to titanium and hydroxyapatite implants.
Keywords: cell culture, hydroxyapatite, immunohistochemistry, implants, osteoblast, titanium, transmission electron microscopy
Pages 466-475, Language: English
The aim of this investigation was to determine the long-term clinical outcome and predictability of the maxillary sinus augmentation procedure utilizing a variety of bone augmentation materials. The augmentation materials evaluated were a xenograft alone (Bio-Oss), an alloplast alone (Interpore), a xenograft-alloplast combination (Bio-Oss mixed with Interpore in a 1:1 ratio), an alloplast (Interpore) mixed with autogenous bone from the iliac crest (in a 1:3 ratio), and an alloplast (Interpore) mixed with autogenous bone from the chin (in a 1:1 ratio). A total of 340 plasma-sprayed cylinder implants (IMZ) were placed, either simultaneously with the sinus augmentation procedure (235 implants), or 6 months after the procedure (105 implants) in 133 patients with insufficient bone volume in the posterior maxilla. The implants were restored with a total of 151 fixed detachable ceramometal prostheses and evaluated up to a 5-year period. Clinical evaluations included yearly assessments of peri-implant inflammation, implant mobility, and clinical attachment levels. Radiographs were also taken prior to sinus augmentation surgery, at abutment connection, at completion of the restoration, and thereafter at yearly intervals. All of the implants placed into the augmented sinuses achieved osseointegration. Only four implants (1.2%) failed to maintain osseointegration after prosthesis placement, yielding an implant survival rate of 98.8% during the entire course of the study. Of the 340 implants, 307 (90.3%) were considered successful according to the success criteria used. Gender, implant length and location, remaining bone height, and type of bone augmentation material had no effect on implant success. None of the 151 prostheses was lost during the observation period. The results of this study support the long-term clinical predictability of maxillary sinus augmentation procedures for the rehabilitation of the edentulous posterior maxilla with implant supported prostheses.
Keywords: dental implant, implantology, oral surgery, prosthodontics, sinus augmentation
Pages 476-488, Language: English
This study reviews 29 consecutively treated patients who underwent a variety of autogenous alveolar augmentation procedures to their resorbed maxilla or mandible followed by delayed placement of Brånemark dental implants. One additional patient had frozen femoral head allogenic bone as a graft. A suggested treatment protocol is outlined for rehabilitation of the resorbed maxilla and mandible without the need to compromise the basic biologic principles of osseointegration proposed by Brånemark. A total of 114 implants were placed in the grafted areas. Twelve implants were removed from three patients. This represents a success rate of 100% in the mandible and 86% in the maxilla. As a result of this treatment, 28 patients wear fixed implant-supported prostheses, and two patients wear overdentures.
Keywords: allogenic, autogenous, bone grafting, delayed graft, implant placement, mandible, maxilla, osseointegration, titanium implant
Pages 489-497, Language: English
The purpose of this study was to evaluate immediate implants with implants placed in ossified extraction (control) sites. Histologic observation of immediate and control implants showed similar levels of bone integration at the light microscopic level using ground-section and decalcified thin-section histologic methods. Both histologic methods provided similar information in relation to determination of hard and soft tissue components measured at the interface. The percentage of bone integration was similar in different anatomic regions of the oral cavity. Bone patterns peripheral to the interface region differed, suggesting that special consideration be given to implants placed in the posterior regions of the maxilla and mandible.
Keywords: animal, endosseous dental implant, histology, immediate implantation, osseointegration, titanium, tooth extraction
Pages 498-505, Language: English
Thirty 8-week-old male Wistar rats were randomly allocated into three groups of 10 rats each. A 5-mm defect in the left parietal bone was made in each rat. In the defects of the first group of rats, no implant was used (control group). In the second group, polyorthoester membranes were placed in the defects without active substance. In the third group, polyorthoester membranes were placed with insulinlike growth factor I. The rats were sacrificed 6 weeks postoperatively. Bone formation in the defects was quantified by computer-assisted measurements of the area of the residual defect on radiographs. Host-tissue response was evaluated by light microscopy. The area of residual bone defect was greatest in the control group, less for the defects with polyorthoester membrane without active substance, and least for the defects with polyorthoester membranes with the growth factor. During histologic evaluation, no inflammation was seen, and only traces of the polyorthoester were detected in the defects with polyorthoester membrane with or without the growth factor.
Keywords: bone defect, bone healing, growth factor, guided bone regeneration, membrane
Pages 506-511, Language: English
Two types of threaded titanium implants (Euroteknika and Nobel Biocare) were compared in a 180-day in vivo experiment in sheep. The implant characteristics were analyzed by scanning electron microscopy and image analysis to determine the roughness index of the surface. Implant specificity appeared through their slightly different chemical composition, their peculiar thread morphology, and their different roughness indexes (0.214 and 0.139, respectively). Implants were placed in the distal part of the tibial diaphysis. Histomorphometric analysis of the bone-implant interface was done on bone sections processed undecalcified. Both types of implants exhibited a similar bony reaction, with haversian bone in close contact with the titanium surface without interposition of fibrous tissue. The interface length percentage covered by bone was not significantly different between the two types of implants.
Keywords: bone-titanium interface, dental implants, histomorphometry, scanning electron microscopy, titanium implants
Pages 512-521, Language: English
The aim of the present retrospective study was to evaluate the results of a one-stage reconstructive procedure using titanium implants placed in iliac corticocancellous bone blocks grafted to the floor of maxillary sinuses. Forty-nine patients received 314 Brånemark implants, of which 171 implants of various lengths were placed in the grafted bone and 143 implants in the adjacent maxillary alveolar process (which includes 11 implants placed in onlay grafts). Five patients also received onlay grafts to the anterior maxilla. Follow-up time was 3 to 49 months after abutment connection, which was performed 9 months after implant placement. Eighty-two percent of the implants were successfully integrated in the grafted area and 84.8% in the adjacent bone. Eleven patients (22.4%) lost one to four implants or a few implants in strategic positions, requiring secondary implant placement prior to the manufacturing of fixed prostheses, whereas 35 (71.4%) received primary fixed restorations. Only two individuals (4.1%) received permanent implant-supported overdentures. Assessments of esthetics, phonetics, and function were made by the surgical-prosthodontic team and compared with those of the patients. Opinions regarding the functional outcome of treatment appeared least correlated. The total implant survival rate compares favorably with other reports.
Keywords: bone grafting, endosseous implants, maxillary sinus augmentation, oral rehabilitation
Pages 522-528, Language: English
The load fatigue performance of the CeraOne and EsthetiCone implant systems was investigated. Three torques (standard torque, standard torque + 20%, and standard torque - 20%) were used to tighten the screws. A rotating-beam fatigue model was used. A 70-N load was applied to the specimens at a 30-degree angle to the long axis. Two-way analysis of variance revealed (1) no statistically significant difference between the three torques for each system, and (2) a statistically significant difference between the implant systems. Implant failure occurred in 10 of 15 CeraOne specimens. In the EsthetiCone system, only abutment screw failure occurred.
Keywords: implant, load angle, load fatigue, torque
Pages 529-533, Language: English
A procedure is presented whereby treatment planning for the long-term restoration of imminent loss of well-rooted posterior maxillary teeth by immediate endosseous dental implant placement may aid the patient in avoiding major surgical reconstruction. The clinical case report presented illustrates the advantages of an immediate dental implant placement technique that is especially relevant and unique to the posterior maxilla. Anatomic advantages are discussed.
Keywords: immediate implant, maxillary molars, maxillary sinus, pneumatization
Pages 534-538, Language: English
In this case report, implants and implant-supported fixed prostheses were used to rehabilitate the anatomy and functioning of the dental arches in a patient who had presented with partial posterior edentulism. Necessary orthodontic treatment was done using provisional implant-supported prostheses as stable anchorage. When completed, the provisional restorations were removed and ceramometal restorations were placed.
Keywords: implant, intraoral stable anchorage, orthodontics, osseointegrated implant
Pages 539-542, Language: English
Osteoporosis is a relative contraindication for osseointegrated implants. This article describes a patient with severe osteoporosis who underwent implant therapy in the mandible. The treatment was carried out in a conventional manner, except for a longer healing period (6 months). All implants had clinically osseointegrated. Furthermore, there was no problem after the superstructure was placed.
Keywords: osseointegrated implant, osseointegration, osteoporosis