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PubMedDate not supplied

Sinus elevation with alloplasts or xenogenic materials and implants: an up-to-4-year clinical and radiologic follow-up.

PURPOSE: The clinical and radiologic results of bone substitute application in the sinus elevation procedure were evaluated for up to 4 years after a grafting procedure followed by implant placement. MATERIALS AND METHODS: Between 1997 and 2001, augmentation of the maxillary sinus floor with alloplastic or xenogenic materials was performed in 34 nonsmoking patients with generally good health. However, only 18 patients attended all of the required annual clinical and radiographic examinations and thus were included in the study. Mean follow-up after implantation was 29 months. RESULTS: At the second-stage surgery all the implants were osseointegrated, except for 1 Frialit-2, which was removed. Following prosthetic rehabilitation no implant was lost after 4 years of function, for a prosthetic success rate of 100%. The cumulative implant survival rate after 48 months was 97% (36 of 37 implants). DISCUSSION: Osseointegrated implants are a reliable treatment option for restoring the posterior maxilla, and final predictability was not influenced by their placement in augmented areas after sinus elevation with bone substitutes. CONCLUSIONS: The survival rate obtained with this study is similar to that expected for implants placed in nongrafted areas. This study showed that alloplasts and xenogenic materials are reliable for bone regeneration in the subantral cavities, as they showed very low resorption in the present study.

Adult↗

PubMed2000

Regenerative periodontal therapy.

Regenerative periodontal therapy comprises procedures which are specially designed to restore parts of the tooth supporting apparatus which have been lost due to periodontitis. A procedure must fulfill certain criteria to be considered a therapy which encourages regeneration. This paper discusses a variety of surgical approaches including root surface conditioning, the placement of bone garfts or bone substitute implants and the use of organic or synthetic barrier membranes (GTR). Evidence is presented that regenerative surgery utilising the GTR principle fulfills all the criteria required of a surgical procedure to be considered a procedure leading to periodontal regeneration.

Animals↗

PubMed2002

Apatite-forming ability of a zirconia/alumina nano-composite induced by chemical treatment.

Induction of an apatite-forming ability on a nano-composite of a ceria-stabilized tetragonal zirconia polycrystals (Ce-TZP) and alumina (Al2O3) polycrystals via chemical treatment with aqueous solutions of H3PO4, H2SO4, HCl, or NaOH has been investigated. The Ce-TZP/Al2O3 composite is attractive as a load-bearing bone substitute because of its mechanical properties. The chemical treatments produced Zr-OH surface functional groups, which are known to be effective for apatite nucleation in a body environment. The composite, after chemical treatment, was shown to form a bonelike apatite layer when immersed in a simulated body fluid containing ion concentrations nearly equal to those in human blood plasma. This implies that it may form apatite in the living body and bond to living bone through the apatite layer. This type of bioactive Ce-TZP/Al2O3 composite is therefore expected to be useful as a bone substitute, even under load-bearing conditions.

Aluminum↗

PubMed2004

Mechanical characterisation of a bone defect model filled with ceramic cements.

Ceramic bone substitute materials are often used to fill defects in comminuted articular fractures. In an in vivo study [1], calcium phosphate cements have been injected into highly loaded slot defects in the proximal tibial metaphysis. During healing, cracks were formed mostly in the proximal anterior aspect of the implanted cement and wedge-like gaps formed between the tibial plateau and the cement. Mechanical ex vivo tests were done to investigate the mechanical competence of the bone cement in such a defect situation. Entirely filled defects were loaded with up to 4.5 kN until they failed. Cyclic loading of the proximal tibiae caused micro fragmentation of the cement after 1000 cycles at 1.5-2.0 kN load. This aspect was comparable to cement fragmentation observed in vivo. Large defects in highly loaded areas should therefore additionally be stabilised with metallic implants. The ceramic cement can only be used as a filler material, which can be replaced by new bone upon resorption.

Animals↗

PubMed1989

[Experimental studies of healing process on compound blocks of hydroxyapatite (HAP) particles and tricalcium phosphate (TCP) powder implantation in rabbit mandible--comparison of HAP/TCP ratios and plastic methods].

Bone substitutes consisting in 2 mold-poured compound blocks of HAP:TCP (mixing ratio 1:1) and HAP:TCP (mixing ratio 3:1) and one compound block (mixing ratio 1:1) prepared in a rubber press were implanted in defective areas in rabbit mandibles. The conditions under which the implants were made were identical in all cases. Histological studies and contact microradiography performed on ossification of the surfaces and surroundings of each block, ossification maturation, and the absorptive process of TCP and the extent to which it was replaced by new bone produced the following results. 1. At one week after surgery, new bone had grown along the surfaces of the blocks. It remained in tight contact with the block surfaces as it matured. These findings make it clear that the blocks are superior in terms of biocompatibility and osteoconduction. 2. In the course of time, in the 2 mold-poured compound blocks, the hydrated parts of alpha-TCP, which was a binder, were absorbed and replaced by new bone. At forty eight weeks after surgery, new bone had grown into the pores of the HAP particles to form a bone-HAP composite. 3. Even as late as forty eight weeks after surgery, some of the hydrated parts of alpha-TCP remained unabsorbed; and mold-poured compound blocks (mixing ratio 1:1) retained their shapes. On the other hand, in the mold-poured compound blocks (mixing ratio 3:1), the hydrated parts of alpha-TCP were almost absorbed and replaced by new bone in forty eight weeks after surgery. Amounts of the binder alpha-TCP present appeared to cause differences in biological reactions. 4. In the case of compound blocks of HAP:TCP (mixing ratio 1:1) formed in a rubber press, the binder was beta-TCP. Because of its high sintering properties and great density, absorption and ossification were gradual; and the blocks retained their complete original forms even in forty eight weeks after surgery. 5. Past reports have claimed that beta-TCP is absorbed in the initial stage. But, as is clear from experiments with compound blocks formed by means of a rubber press, even when the binder is beta-TCP in all cases, absorption speed differs depending on the mold used. 6. These results indicate that compound blocks of HAP and TCP used as artificial substitute bone materials have excellent properties of biocompatibility, osteoconduction, and plasticity. In addition, however, they make it clear that, owing to differences in absorption of the binder, ossification speed, and dynamic properties from block to block, it is essential to use the mold that properly suits conditions prevailing in the defective area.

Animals↗

PubMed1987

Porous hydroxyapatite as a bone graft substitute in diaphyseal defects: a histometric study.

Porous hydroxyapatite (IP200), formed by conversion of the Poritidae porites exoskeleton, has pores averaging 230 microns and pore interconnections averaging 190 microns in diameter. In the distal radial diaphyses of 14 dogs, bilateral 7.5 X 20 mm cortical windows were created and fitted with 5 X 7.5 X 20 mm blocks of IP200 implants and iliac autografts. Both implanted and contralateral grafted radius specimens were retrieved at 3, 6, 12, 24, and 48 months. Unstained undecalcified sections were examined by microradiography and UV epi-illumination. Stained undecalcified sections were examined by light microscopy and quantitated by histometric methods. Implant specimens demonstrated good union and bone ingrowth at all time intervals. The implant specimens were composed of (mean +/- SE) 10.6% +/- 1.0% soft tissue, 51.2% +/- 1.3% bone, and 38.2% +/- 1.0% IP200. The graft specimens showed good union with little apparent ingrowth at 3 months, followed by progressive appositional closure of cancellous spaces. The graft specimens contained 21.9% +/- 0.9% bone at 3 months with increases at each time interval to 73.1% +/- 8.7% at 48 months. The volume fraction and mean width of IP200 did not change with time, confirming the absence of implant biodegradation. The volume fraction and mean width of bone remained stable in the implant but increased in the graft specimens, corresponding to graft neocortex formation. It is concluded that implants initially filled in with bone while grafts initially replaced much of their spongiosa and subsequently filled in with bone. Histometry of untreated defects and measurement of mechanical properties are suggested for further study.

Animals↗

PubMedDate not supplied

A simplified technique for producing platelet-rich plasma and platelet concentrate for intraoral bone grafting techniques: a technical note.

A method to produce platelet-rich plasma and platelet concentrate using a double centrifuge technique in combination with the fibrin adhesive Tisseel is described. This technique constitutes the basic mixture for augmenting and improving an inadequate bone site. Also described is a procedure by which autologous bone or bone substitute is added to this mixture to increase the volume of grafting material. Platelet concentrates cause growth factors to be delivered to graft sites in an intense form, while Tisseel serves as a standardized, pharmaceutically manufactured fibrin adhesive.

Alveolar Ridge Augmentation↗

PubMed2000

[Implantology].

Endosseous osseointegrated implants have become an integral part of the treatment scheme for the prosthetic reconstruction and rehabilitation of masticatory function following scientific studies of the reactions between implant and soft and hard tissues. Furthermore, implants offer good chances for prosthetic rehabilitation in the insufficient bone site, if the extremely atrophic jaw is to be reconstructed by grafting procedures with avascular and vascular grafts, by guided bone regeneration, by distraction osteogenesis, by bone substitutes and in the future by osteoinductive proteins in order to prepare the conditions for implant insertion. Those reconstruction procedures combined with implants become often necessary, if complicated hard and soft tissue defects of the skull have to be reconstructed to create the prerequisites for the stabilisation of epitheses or to insert implant-supported devices.

Bone Regeneration↗

PubMed2002

Current concepts of periodontal regeneration. A review of the literature.

The purpose of this article is to provide a review of the various regenerative therapies and materials in use today, along with treatment and patient variables that may affect outcome predictability. Future direction in this ever-changing field is also discussed. Techniques currently in use are reviewed and evaluated. They include open flap debridement, the use of bone grafts and bone substitutes, guided tissue regeneration, combination techniques, root surface treatment and the use of biologics. Clinical and histological human studies employing the above-mentioned treatments are discussed. The advantages and disadvantages of each treatment modality are discussed, along with patient and local factors that have been shown to affect success rates.

Absorbable Implants↗

PubMed2003

[The armamentarium of the periodontologist].

The aim of this article is to describe the products available to the periodontist for the regeneration of bone and periodontal tissues. According to distinct biological mechanisms responsible for their regenerative potential, these products can be classified upon three groups: bone substitutes, membranes and enamel matrix proteins. The rationale for trying to regenerate the periodontium after the initial non-surgical phase of the periodontal treatment is discussed. The indications of these products according to their biological principles are described as well as their limitations. The safety of the products of allogenic origin is discussed.

Alveolar Bone Loss↗

PubMed1987

The John Charnley Award paper. Efficacy of using a bone graft substitute to enhance biological fixation of a porous metal femoral component.

The efficacy of using hydroxyapatite/tricalcium phosphate (HAP/TCP) particles to enhance the biological fixation of a canine cementless femoral component with a noninterference fit was evaluated with a custom-designed collarless, wedge-shaped femoral component with titanium fiber metal pads along the anteroposterior surfaces of the stem. A polyethylene acetabular component was cemented into the pelvis. Three groups of dogs were employed: group I (n = 7) had a femoral component with an interference fit; group II (n = 6) had a component with a noninterference fit with uniform voids along the anteroposterior stem surfaces; and group III (n = 6) had a component with a noninterference fit including uniform voids filled with HAP/TCP particles. All dogs were harvested after 12 weeks of unrestricted weight bearing. Cross-section specimens from three different levels from each bone-component composite were evaluated histologically to determine the type and extent of tissue ingrowth and the percentage of peripheral bone or HAP/TCP particles adjacent to the fiber metal pad surfaces. Three other cross-section specimens, adjacent to the histological section levels of the same composites, were assessed for shear strength at the fiber metal-tissue interface and for biochemical composition of the ingrown tissue.

Animals↗

PubMed1997

[Role of coral blocks in cheek augmentation surgery. Prospective study of 23 patients].

A two-year multicentre prospective study was performed from 1992 to 1995 in order to evaluate the real value of various kinds of coral blocks as bone substitute in maxillofacial surgery. This study was supported by the French National Agency for Research Valorization (GBM/TEP procedure). Ten Maxillofacial Surgery Units were included. During this time, 28 coral blocks (23 patients) of two different shapes were used as malar implants for correction of congenital or acquired zygomatic hypoplasia. The mean follow-up was 1.8 year (min: 1.5; max: 2). The tolerance was perfect for 89% of cases. The radiologic opacity never decreased more than 30% and the volume augmentation was always stable at the end of the follow-up period. Three implants were removed because of septic complications. Rigid fixation between the implant and the zygomatic bone appears to be the most important factor of success. On the other hand, the surgical approach (endo- or exo-buccal) does not seem to influence the success rate. The aesthetic improvement was always evaluated as satisfactory and stable by the patients and the surgeons. The authors discuss the real value of the various kinds of biomaterials and especially coral, comparing their personal data with those of the literature. Coral blocks clearly constitute a safe and reliable bone substitute, but further investigations are required to determine its long-term behavior.

Adolescent↗

PubMed1998

In vitro evaluation of a new injectable calcium phosphate material.

The purpose of this study was to develop an injectable bone substitute (IBS) for percutaneous orthopedic surgery. The multiphasic material used was composed of a 2% aqueous solution of methylhydroxypropylcellulose (MHPC) and biphasic calcium phosphate (BCP, 60% hydroxyapatite and 40% beta-tricalcium phosphate) in which MHPC served as the carrier for 80-200 microm of BCP granules. The best BCP/polymer ratio was determined by the rheological properties and higher BCP content of the material. Steam sterilization was more effective than gamma irradiation in maintaining the stability of the mixture and conserving its physiochemical and mechanical properties. The in vitro biocompatibility of the composite was checked by direct-contact cytotoxicity and cell-proliferation assays. A preliminary in vivo test was performed in the rabbit using intraosseous implantations in the femoral epiphysis. Histological analysis was done after 1, 2, 4, and 10 weeks. Bone ingrowth into the IBS, in close association with BCP granules, was observed after 1 week and increased regularly from the surface inward at 2, 4, and 10 weeks. At the same time, smaller BCP granules (less than 80 microns in diameter) were degraded and resorbed. This injectable biomaterial proved suitable for cavity filling. The water solubility and viscosity of the polymer allow cells to recolonize, with in situ bonding of the mineral phase.

Animals↗

PubMed2005

Long-term success of sinus augmentation using a synthetic alloplast: a 20 patients, 7 years clinical report.

An adverse architecture of the maxillary sinus is no longer a contraindication for implant placement. Grafting the sinus has become an accepted treatment modality. Techniques for lifting the sinuses are well documented and numerous articles have been published. The main difference between the multitude of articles seems to be the graft material used. After having used different grafts, with varying success, this article reflects the authors' impressions on one particular grafting material, a composite synthetic bone substitute. The objective of this clinical study was to evaluate the effectiveness, reliability and predictability of that synthetic graft material (Bioplant HTR). After treating 20 patients (22 sites, 56 implants), and after a follow-up period as long as 7 years, it was clinically and radiographically observed that achieved results are enhanced if this synthetic graft material is used and that its use enhances sinus augmentation outcome and predictability. It provides the patient with the benefits of implant-supported restorations in a simple, quick, cost-effective, predictable, and secure manner.

Adult↗

PubMed2002

Controlled trial of distal radial fractures treated with a resorbable bone mineral substitute.

This randomized trial compared the use of hydroxyapatite cement with Kapandji wiring in distal radial fractures. Two groups of nine patients with distal radial fractures were either treated by reduction and fixation with wires or insertion of the cement into the fracture void. There was no difference between the groups before operation, on reduction or at day 1. Dorsal angle in the hydroxyapatite group was significantly worse at 6, 12 and 26 weeks. Grip strength and palmar flexion were poor in the hydroxyapatite cement group. All the clinical parameters and X-ray variables were worse at 12 and 26 weeks in the hydroxyapatite cement group. We conclude from this trial that there is nothing to support the use of this hydroxyapatite cement, without the use of additional fixation, in distal radial fractures.

Aged↗

PubMed1991

Effects of calcium-phosphate-based materials on proliferation and alkaline phosphatase activity of newborn rat periosteal cells in vitro.

The effects of dental materials, intended for bone substitution, on cell growth and alkaline phosphatase activity of newborn rat periosteal cells have been studied in vitro. Confluent periosteal cells were exposed to three apatite-based materials (400 micrograms/mL) with different physico-chemical properties. The materials were a beta-tricalcium phosphate with a microporous granular structure obtained by sinterization (Synthograft, Johnson & Johnson, East Windsor, NY), a 40-60-mesh microporous durapatite ceramic (Periograf, Sterling Drug, Inc., Rensselaer, NY), and a 1-2-mm-diameter hydroxyapatite ceramic (Osprovit, Feldmuhle Aktiengeselschaft, Plochingen, Germany) with macropores larger than 100 microns. Cell proliferation and alkaline phosphatase activity were assessed by incorporation of 3H-thymidine into trichloroacetic-acid-precipitable material and by a fluorimetric method, respectively. Cell viability and compatibility with the materials were determined by morphology in phase-contrast microscopy. Periosteal cells showed increased proliferation following exposure to Synthograft, but were unaffected by Osprovit, whereas Periograf caused significantly reduced cell growth. Alkaline phosphatase activity was unaffected by Osprovit, but was decreased by both Synthograft and Periograf. The results indicated a differential response of periosteal cells to bone-substituting materials with heterogeneous physico-chemical characteristics.

Alkaline Phosphatase↗

PubMed2003

Severely impacted valgus proximal humeral fractures. Results of operative treatment.

BACKGROUND: The functional results associated with nonoperative treatment of severely impacted valgus fractures of the proximal part of the humerus are poor, and these injuries are difficult to treat with minimally invasive percutaneous fixation techniques. The aim of this study was to review the functional and radiographic results and complications of a new operative technique in a series of twenty-five patients. METHODS: Over a two-year period, we treated twenty-nine patients with a severely impacted valgus fracture of the proximal part of the humerus. Three patients were lost to follow-up and one died, leaving twenty-five patients who were available for the study. In all of the fractures, the head-shaft angle had been tilted into > or = 160 degrees of valgus and the greater tuberosity was displaced by >1 cm. All patients were treated with open reduction of the fracture, and the space created behind the humeral head was filled with Norian Skeletal Repair System (SRS) bone substitute. The fractures were stabilized with either screws or buttress plate fixation. Associated rotator cuff tears were repaired. All patients underwent functional outcome assessment with use of the Constant, DASH (Disabilities of the Arm, Shoulder and Hand), and SF-36 (Short Form-36) scores at one year, and twelve patients were followed for two years. RESULTS: All fractures united within the first year, all reductions were maintained, and no patient had signs of osteonecrosis of the humeral head on the latest follow-up radiographs. At one year, the median Constant score was 80 points and the median DASH score was 22 points. The functional results continued to be satisfactory in the twelve patients who were followed for two years. The results in our series were better than those achieved in studies of nonoperative treatment of similar fracture configurations. There were six clinically relevant complications, although none required a reoperation and all six patients had a satisfactory short-term functional outcome. CONCLUSIONS: Internal fixation of severely impacted valgus fractures of the proximal part of the humerus, supplemented by Norian SRS bone substitute to fill the proximal humeral metaphyseal defect, produces good early functional and radiographic outcomes. Additional follow-up will be required to assess whether these initially satisfactory outcomes are maintained over the longer term.

Adult↗

PubMed2004

Severely impacted valgus proximal humeral fractures.

Contraindications↗