Deproteinized cancellous bovine bone (Bio-Oss) as bone substitute for sinus floor elevation. A retrospective, histomorphometrical study of five cases.

OBJECTIVES: To study in detail the performance of deproteinized cancellous bovine bone (DPBB, Bio-Osso) granules as a bone substitute, a histomorphometric was performed on five patients treated with DPBB for reconstruction of the severely atrophic maxilla. MATERIAL AND METHODS: DPBB was used as mixture with autogenous bone particles, in concentrations that increased from 20% to 100% DPBB, with the time of healing increasing accordingly from 5 to 8 months. A total of 20 vertical biopsies was taken at the time of fixture installation and used for histomorphometry as undecalcified Goldner stained sections. RESULTS: The results show that in all cases, the DPBB granules had been interconnected by bridges of vital newly formed bone. The volume of bone in the grafted area correlated inversely with the concentration of DPBB grafted, and varied between 37% and 23%. However, the total volume of mineralized material (bone plus DPI3B granules) remained within the same range in all five patients (between 53% and 59%). The high values for osteoid and resorption surface, and the presence of tartrate-resistant acid phosphatase-positive multinucleated osteoclasts in resorption lacunae, indicated that bone remodeling was very active in all grafts. Osteoclasts were also observed in shallow resorption pits on DPBB surfaces. The percentage DPBB surface in contact with bone remained stable at about 35% and could not be related to the proportion of DPBB grafted. CONCLUSION: Although the number of patients examined was limited, the data suggest that deproteinized cancellous bovine bone, preferably combined with autogenous bone particles, is a suitable material for sinus floor elevation in the severely atrophic human maxilla.

Histology of human alveolar bone regeneration with a porous tricalcium phosphate. A report of two cases.

Porous beta-phase tricalcium phosphate particles (pTCP) (Cerasorb) were used in two patients to restore or augment alveolar bone prior to the placement of dental implants. In one patient, pTCP was used to fill a large alveolar defect in the posterior mandible after the removal of a residual cyst, and in another patient to augment the sinus floor. Biopsies were taken at the time of implant placement, 9.5 and 8 months after grafting, respectively, and processed for hard tissue histology. Goldner-stained histological sections showed considerable replacement of the bone substitute by bone and bone marrow. In the 9.5 months biopsy of the mandible, 34% of the biopsy consisted of mineralised bone tissue and 29% of remaining pTCP, while the biopsy at 8 months after sinus floor augmentation consisted of 20% mineralised bone and 44% remaining pTCP. Bone and osteoid were lying in close contact with the remaining pTCP and were also seen within the micropores of the grafted particles. Tartrate resistant-acid phosphatase (TRAP) multinuclear cells, presumably osteoclasts, were found surrounding, within and in close contact with the pTCP particles, suggesting active resorption of the bone substitute. Remodelling of immature woven bone into mature lamellar bone was also found. No histological signs of inflammation were detected. The limited data presented from these two cases suggest that this graft material, possibly by virtue of its porosity and chemical nature, may be a suitable bone substitute that can biodegrade and be replaced by new mineralising bone tissue.

Histological observations on biopsies harvested following sinus floor elevation using a bioactive glass material of narrow size range.

We evaluated the bone augmenting capacity of bioactive glass particles, size range 300-355 microns (BG-particles), in human sinus floor elevations using histomorphometrical methods. A total of 10 patients underwent bilateral grafting, using a 1:1 mixture of autogenous bone particles (from iliac crest) and BG-particles at one side (experimental side), and bone particles only at the other side (control side, split mouth design). A total of 72 bone biopsies were taken at the time of fixture installation; that is, 3 patients at 4 months, 3 at 5 months and 3 at 6 months after grafting and 1 patient at 16 months (when she presented again). In each case 6 biopsies were taken, 3 left and 3 right. Histomorphometry showed that in grafts at control sides, trabecular bone was present after 4 months, comprising almost 41% of the tissue volume. This bone contained viable osteocytes and was of mature lamellar type and showed a mature histological appearance. Bone volume continued to increase slightly, to 42% at 5 months, 44% at 6 months and 45% at 16 months. The graft volume at experimental sides consisted at 4 months for 28% of woven and some lamellar bone, and increased to 35% at 5 months and 38% at 6 months, when mainly lamellar bone was found. At 16 months a lamellar bone volume of 45% was found. The BG-particles transformed and became excavated with time, starting at 4 months, and their centers gradually filled with bone tissue. All BG-particles had disappeared by resorption at 16 months after grafting and had been replaced by bone tissue. Parameters of bone turnover (% osteoid surface, % resorption surface, mineral apposition rate as measured by tetracycline labeling) indicated that bone remodeling was very active at both sides, during more than 6 months, despite the mature histological appearance of the bone tissue. From these histological observations, we conclude that a 1:1 mixture of autogenous bone/BG-particles seems a promising alternative to autogenous bone only, when low amounts of bone tissue are available for sinus augmentation.

A clinical evaluation of 76 implant-supported superstructures in the composite grafted maxilla.

The aim of the study was to evaluate the material behaviour and nature of implant-supported superstructures in function. A total of 37 overdentures, 26 fixed partial and 13 fixed full dentures with a mean lifetime of 40 months were clinically evaluated in relation to damage, occlusion and articulation, parafunction, retentive devices, hygiene and speech problems. In general 70% of all superstructures were damaged. Fixed partial dentures were significantly less damaged than overdentures and fixed full dentures (P<0.001). A significant high percentage of newly gained parafunction was found (P<0.05).

Peri-implant tissue health in reconstructed atrophic maxillae--report of 88 patients and 470 implants.

The aim of this study was to evaluate the soft-tissue health around 470 implants placed in the upper jaw of 88 patients with severe maxillary atrophy. All patients underwent a reconstruction procedure which included a composite bone grafting from the iliac crest to the maxillary sinus. Evaluation was performed at a mean implant lifetime of 21.6+/-10.9 months. The following parameters were used: probing depth, plaque-, gingival-, bleeding index and width of the buccal keratinized mucosa. They were calculated as means for each implant and related to the type of superstructure and the thickness of the original sinus floor. (higher or lower than 5 mm). A high percentage of bleeding on probing was observed in obviously clinically healthy peri-implant pockets. Bleeding on probing and deeper probing depth were especially observed in the group with severe maxillary atrophy (less than 5 mm initial height of the sinus floor.) There was a significant increase in mean peri-implant probing depth and gingiva index in overdentures versus fixed bridges. No differences were observed with respect to the width of the keratinized buccal mucosa. It was concluded that implants in the reconstructed maxilla and supporting overdentures had a higher risk for bone loss, based on the worse peri-implant tissue health observed.

[Single tooth replacement with an implant. Possibilities and limitations]. / Solitaire tandvervanging door implantaten. Mogelijkheden en beperkingen.

Implant treatment in case of a single missing tooth can potentially lead to a well functioning and aesthetically pleasing single crown on an implant. However, in order to achieve an optimal treatment result, a long road has to be travelled since usually resorption defects have to be repaired and soft tissue corrections are frequently necessary. This paper provides information regarding commonly observed situations and their consequences for the prognosis of implant treatment. It is concluded that a single tooth implant can be an elegant solution, though not an easy one. It requires a high degree of experience and surgical and prosthetic capabilities of the dentist. The natural situation can only be mimicked if all stages of treatment are adequately planned and conducted and if no major complications occur in the process. To prevent disappointments, both dentist and patient should be well aware of all conditions required for an optimal result.

Dental implants in the atrophic maxilla: measurements of patients' satisfaction and treatment experience.

Maxillary bone reconstruction in combination with placement of dental implants is a treatment modality reported since 1980 for patients suffering from maxillary atrophy and difficulties with wearing removable prosthesis. This study reports on patient experience and satisfaction among 88 consecutive patients concerning surgical and prosthetic aspects of their treatment. A questionnaire was used to gather the data. Patient satisfaction was measured on a scale from 1 to 5 (1 = bad/few, 5 = very good/much). The satisfaction index with regard to the total treatment was 4.1 +/- 0.9. A total of 90% of the patients responded that they would go through the treatment again or recommend the treatment to a friend if necessary. The post-operative pain index scored 2.6 +/- 1.2. The acceptation of the post-operative pain at the crista iliaca was 86.1% and of the maxilla 89.9%. It is concluded that the results of measurements of patient satisfaction after maxillary bone reconstruction in combination with placement of dental implants were acceptable.

Survival of cylindrical implants in composite grafted maxillary sinuses.

PURPOSE: This retrospective study investigated the survival of dental implants placed in the maxilla after composite grafting of the sinus and an average of 55 months of loading. PATIENTS AND METHODS: Maxillary sinuses of 88 patients were grafted with autogenous cancellous bone combined with dense hydroxyapatite particles. After an average healing period of 3.4 months, hydroxyapatite-coated titanium endosseous implants were placed. A total of 388 implants were placed in grafted sinus floors, and 82 were placed in onlay grafted nonsinus position in the canine region. The implants were loaded with overdentures and fixed bridges 4 months (mean) after implantation, with a follow-up for a mean of 55 months. RESULTS: The cumulative implant survival was calculated according to the Kaplan-Meier method. Implant survival from the time of loading was 89% in full reconstructed cases and 90% in partially edentulous cases. The overall cumulative implant survival rate, including the loss in the surgical stage, was 82%. CONCLUSION: Implant loss in composite grafted maxillae after 70 months of follow-up was similar to loss in nongrafted maxillae.

[Guided bone regeneration for dental implantology]. / Geleide botregeneratie in de implantologie.

Guided bone regeneration nowadays offers good possibilities to repair local bone defects. Membranes are used to cover the defects. There are many types available. The anatomy of the defect determines mainly which membrane type should be used or which surgical steps should be followed. Most difficult are the one-wall defects, less difficult are four-wall defects. Guided bone regeneration is predictable, but the procedure is technical sensitive and complications and contaminations will easy occur. All steps need to be done carefully, including patient selection and postoperative follow-up care. Implant insertion into the defect can be done simultaneously but will give a higher risk for complications. For this reason, care should be taken for regeneration procedures in aesthetic demanding areas.

[Bone quality after sinus floor augmentation]. / Botkwaliteit na sinusbodemverhoging.

The problem of insufficient alveolar bone in the edentulous maxilla caused by resorption and pneumatization can be overcome by augmentation of the sinus floor to increase bone volume for the placement of dental implants. The quality of bone which is achieved after sinus floor augmentation is hardly known. This study describes the histologic results obtained three till six months after sinus floor augmentation with autogenous bone from the iliac crest in patients with severe maxillary bone resorption. The bone biopsies taken from the implant sites showed a substantial bone volume with a mature trabecular pattern and active bone growth. It was concluded that with the obtained bone quality, the sinus floor augmentation procedure can be a good treatment modality for the rehabilitation with implants in patients with severe maxillary bone atrophy.

[Five-year evaluation of implants in the resorbed maxilla]. / Vijfjaarsoverleving van implantaten in de geresorbeerde bovenkaak.

The survival of implants placed in the resorbed maxillae was investigated. Both edentulous and partially edentulous patients were evaluated including those who underwent 'sinus lift' procedures. The group of patients with a sinus floor augmentation showed a five-year cumulative survival rate varying between 100% for fixed bridges on implants in the partially edentulous maxillae and 75.6% for implants under overdentures placed in severely resorbed edentulous maxillae. It is concluded that placement of implants in the augmented sinus-floor is justified, if the patient is well informed. The procedure can provide a good solution for the prosthetic problems of patients with a resorbed maxilla.

Effects of hydroxyapatite particles on periodontal ligament fibroblast-like cell behavior.

Although hydroxyapatite (HA), a synthetic calcium phosphate, is used in restoring bone defects associated with periodontal diseases, its specific effect on the periodontal ligament fibroblast population during the regeneration process is unclear. To determine the cellular events occurring in the presence of HA, human periodontal ligament fibroblasts (HPLF) were isolated and maintained in culture. The specificity of the cells was evidenced by their morphology, deposition of extracellular matrix components, and alkaline phosphatase (ALP) activity (as a marker of osteoblastic differentiation of HPLF). Phase-contrast investigations revealed morphological alterations of cells in contact with HA particles. Transmission electron microscopy demonstrated the phagocytotic process of HPLF toward HA particles. Moreover, the presence of HA particles was significantly related to an increase in the protein synthesis activity and a decrease in the proliferation and ALP-specific activity of HPLF. These results provide new information on the phenotypic expression of HPLF, which is comparable to that of osteoblastic cells. A subpopulation of HPLF may be influenced by the presence of HA to undergo transient dedifferentiation prior to redifferentiating into osteoblasts. This process may be important as a means by which HA acts as an osteoconductive material. This experimental study improves our understanding of the cellular processes which occur during healing and regeneration of periodontal defects after implantation of biomaterials.

[The atrophic maxilla. Rehabilitation by bone reconstruction, implants and permanent or removable dentures]. / De geresorbeerde bovenkaak. Rehabilitatie met behulp van botreconstructie, implantaten en vaste of uitneembare prothetische voorzieningen.

Maxillary bone reconstruction in combination with placement of endosseous dental implants is a new treatment modality for patients suffering from maxillary atrophy and difficulties with wearing removable prosthesis. Among 88 patients the experiences with and their satisfaction at parts of the treatment were investigated. Patients could express their appreciation in a 1-5 scale (1 = bad, 5 = good). The satisfaction at the total treatment was given the mean figure 4.1 +/- 0.9. Ninety percent of the patients would go through the treatment again when necessary.

Aesthetic and prosthetic principles for single tooth implant procedures: an overview.

Loss of anterior maxillary teeth always results in bone resorption and loss of interdental papillae, making a single tooth replacement by an implant very difficult. When infections have been present and previous surgery at the apex of the root has taken place, bone destruction is substantial, increasing the resorption defect and aesthetic and prosthetic problems. The learning objective of this article is to describe the steps necessary for implant surgery and prosthetics. It includes bone regeneration procedures, implant placement, second stage surgery, reconstruction of interdental papillae, abutment selection, and the various prosthetic procedures. Several cases are used to illustrate.

Front tooth replacement with Tübingen (Frialit) implants.

127 Tübingen (Frialit) implants have been clinically evaluated for a 10 year period. The implants were placed in the anterior region of the maxillae of 101 patients to replace lost incisors, cuspids and premolars. Seventy-seven implants were placed within 3 months after loss of a natural anterior tooth, resulting in the preservation of the volume of the alveolar ridge and the contour of the surrounding soft tissues. This preservation of the volume of the alveolar ridge was due to the fact that the Tübingen implants have conical shapes and sizes, equal to those of the roots of natural teeth. The dentine-like colour and the biological properties of the bio-inert Al2O3 implant-material, in most of the cases was an advantage to the aesthetics of the prosthetic restorations and to the condition of the soft tissues in the permucosal area. The Tübingen implant is placed with a one-phase technique implying special care for the temporary restorations to avoid premature loading. Also prevention of overloading the ceramic material by the fixed restoration needs special attention in the construction of posts, cores and crowns. The overall survival-rate in this study with a mean follow-up of 4.5 years was 87%. Patient and dentist satisfaction was high.

[Esthetic and prosthetic procedures in single-tooth replacement]. / Esthetiek en prothetiek bij enkelvoudige tandvervanging.

Loss of anterior maxillary teeth always results in bone resorption and loss of interdental papillae, and the resorption makes a single tooth replacement by a dental implant very difficult. When infections have been present and the patient's history shows previous surgery at the apex of the root, bone destruction is substantial, which results in an increased resorption defect, thereby further increasing the aesthetic and prosthetic problems. This paper describes the steps necessary for implant surgery and the prosthetics; a brief summary is provided. The quality and quantity of bone, along with the space available between the adjacent teeth, are the basic factors in treatment planning and determine the type of implant to be used. Some resorption and bone defects are usually present after a tooth extraction, and bone regeneration procedures can be performed either before or simultaneously with the implant placement, with numerous flap designs available. Soft tissue augmentation can be achieved by taking a connective tissue graft from the palatal side. Antirotational devices (eg, hex lock abutments) are necessary for all implants in single tooth replacement. Screw-retained abutments can be used in posterior areas and in angled positions in facial areas as well. With proper single tooth implant position, cementation of laboratory fabricated crowns can be considered.

Local residual ridge augmentation with solid hydroxyapatite blocks: Part II--Correction of local resorption defects in 50 patients.

Replacement of anterior teeth with fixed or removable prostheses is often a compromise, because the resorbed residual ridge in the area of missing teeth cannot be ideally restored functionally and esthetically at the same time. To address this problem, 67 blocks of hydroxyapatite were placed subperiosteally to improve residual ridge resorption defects subsequent to loss of anterior teeth in 50 patients. The implants were evaluated clinically and radiographically for 6 months to 7 years after implantation. Results indicate that the suggested approach improves the esthetic results and the prognosis of fixed prostheses.

Local residual ridge augmentation with solid hydroxyapatite blocks: Part I--An animal experiment.

Twenty-four implants were placed in the jaws of five dogs for evaluation of the possibility of correcting local resorption. Implants and surrounding tissues were evaluated clinically, radiographically, and histologically for periods of 3 to 24 months. The implants were clinically and radiographically stable. Some were surrounded by connective tissue fibers and others were bonded to underlying cortical bone.

[Are quality and efficiency in implantology possible in dental general practice?]. / Is kwaliteit en efficiëntie in de implantologie haalbaar in de algemene praktijk?

This article describes the different steps necessary for dental implantations. It is discussed if and how these steps can be performed efficiently by general practitioners. The conclusion is made that there are limitations mostly related to the individual situation in the office, the knowledge and experience available and the complexity of the patients' situation. However, the indication, the implant decision and the general information can be done efficiently by general practitioners.

Dutch consensus on guidelines for superstructures on endosseous implants in the edentulous mandible.

This consensus report has been reached under the authority of the Dutch Society for Oral Implantology and the Dutch Society for Prosthetic Dentistry by a panel of Dutch dentists and prosthodontists (listed above) who are involved in the treatment of patients with oral implants, either via practice or via research. They were commissioned with a task to "formulate guidelines for the prosthetic treatment of edentulous patients receiving oral implants in the mandible".