Custom-made, selective laser sintering (SLS) blade implants as a non-conventional solution for the prosthetic rehabilitation of extremely atrophied posterior mandible.

The treatment of severely atrophied posterior mandibles with standard-diameter root-form implants may present a challenge. Bone reconstructive surgery represents the treatment of choice; however, it may not be accepted by some patients for economic reasons or due to higher morbidity. Computer-aided design/computer-aided manufacturing (CAD/CAM) technologies have recently opened new frontiers in biomedical applications. Selective laser sintering (SLS) is a CAD/CAM technique that allows the fabrication of complex three-dimensional (3D) structures created by computer-generated image-based design techniques. The aim of this study is to present a protocol for the manufacture and clinical use of custom-made SLS titanium blade implants as a non-conventional therapeutic treatment for the prosthetic rehabilitation of extremely atrophied posterior mandibles. Computed tomography datasets of five patients were transferred to a specific reconstruction software, where a 3D projection of the atrophied mandible was obtained, and custom-made endosseous blade implants were designed. The custom-made implants were fabricated with SLS technique, placed in the extremely atrophied posterior (<4 mm width) mandible, and immediately restored with fixed partial restorations. After 2 years of loading, all implants were in function, showing a good esthetic integration. Blade implants can be fabricated on an individual basis as a custom-designed device. This non-conventional approach may represent an option for restoring the atrophied posterior mandible of elderly patients.

Immediate implant placement after removal of a failed implant: a clinical and histological case report.

The purpose of this study was to evaluate the clinical success of an implant placed immediately after the explantation of a fractured blade implant. A healthy 58-year-old male nonsmoker presented with a fractured blade implant that had been subjected to biomechanical overload. A new blade implant was placed immediately after the removal of the fractured one. The new implant was placed with a composite graft of collagen gel and corticocancellous porcine bone and covered with a bioabsorbable membrane. Radiographic evaluation at 6 months postoperation showed complete bone healing. No residual bone defect was observed or probed during the uncovering phase; moreover, no mobility, pain, suppuration, or presence of peri-implant radiolucency were observed at the second-stage surgery.

Placement of plate-form implants using osteotomes.

This article describes the use of osteotomes for the placement of plate-form implants. Comparison is made between the use of cylinders and the plate form as it relates to bone mass and resistant forces. It concludes by showing several cases in function.

[Vertical ridge augmentation using a microplate in conjunction with a Gore-Tex membrane. A case report]. / Aumento verticale della cresta alveolare mediante utilizzazione di una micropiastra in combinazione con una membrana barriera Gore-Tex. Tecnica chirurgica.

Oral implantology is considered an acceptable treatment modality to replace missing teeth when a recipient site with a sufficient horizontal and vertical bone volume exists. Guided bone regeneration is based on the principle of selective exclusion of non osteogenic cells from the bony defect by a barrier membrane. Several supporting systems of the barrier membrane have been successfully used to treat non space-mantaining de-fects. A 35-year-old female affected by a partial edentulism in the molar area of the right mandible showed 8 mm of bone height of the residual ridge above the alveolar canal. A vertical ridge augmentation was performed using a Gore-Tex membrane in conjunction with a microplate and an irradiated freeze-dried cortico-cancellous allograft. Six months after the surgical procedure a 11.5 mm by 5 mm threaded implant was placed into the regenerated bone. After three months of healing, the implant was uncovered and considered integrated. Before the implant placement, a biopsy of the regenerated bone was arried out by a triphine. The histological examination of the bony core showed the attainment of biological goals of guided bone regeneration. The surgical technique followes in this case report has been effective in regenerating a vertical bone volume sufficient for implant treatment.

Morphological study of Osteoplate 2000-extension implants after bending.

Unfavorable anatomical conditions of implant sites often require the insertion of implants in a direction that may interfere with the positioning of suprastructural elements in a functionally and esthetically satisfying manner. In some implant systems, bending of the implant neck is one of the possible methods for optimizing the insertion angle for the superimposed prosthesis. The aim of this study was to investigate whether bending procedures of the implant neck cause changes in the surface properties at the implant neck area. After bending of the implant neck up to 30 degrees, scanning electron microscopy revealed changes in the surface texture of the titanium. Superficial rips approximately 5 microns wide and 100 microns long had formed. These findings were confirmed by metallographic examinations. Values of Vickers hardness testing in the implant neck area after bending of 30 degrees showed significant differences between the compression or stretched zone and the neutral zone of the bending area. Bending of the implant neck between 0 and 20 degrees may influence the surface morphology, promoting superficial rips. Plaque accumulation and mechanically induced mucosal irritations due to changes of surface morphology and properties by bending should be further analyzed.

Composite morphology of the bone and associated support-tissue interfaces to osseointegrated dental implants: TEM and HVEM analyses.

Correlated transmission electron and high-voltage electron microscopic analyses examined the undecalcified bone and associated support tissues of 60 endosseous titanium blade and titanium and ceramic root-form implants in dogs. The implants supported fixed partial dentures for up to 2 years. Data obtained from this investigation suggest that a range of tissues, both mineralized and unmineralized, support osseointegrated dental implants. This study examined the tissues apposing not just isolated aspects of the implant surface, but the entire length of the implant, and found that mineralized and unmineralized tissues existed concurrently. Much of the implant surface was apposed by mandibular bone, and both root-form and blade implants osseointegrated. The densely mineralized collagen fibril matrix was often separated from the implant by only a 20-nm to 50-nm electron-dense, ruthenium-positive deposit. High-voltage electron microscope stereology demonstrated that cellular processes extended directly to the implant from underlying osteocytes. In the same implants, areas containing an unmineralized collagen matrix interposed between the bone and implant surface were observed. In this region osteoblasts interacted with this matrix, and Howship's lacunae, containing vascular elements and osteoclasts, were also observed. The remodeling activities appear to be a homeostasis of catabolic activity (osteoclasts) and metabolic activity (osteoblasts). The apex of the implant was often apposed by a fibrofatty stroma. The support tissue response appears to be the result of the interrelations of osteoblasts, osteocytes, and osteoclasts in association with vascular elements. Therefore, the support tissue response to osseointegrated implants is a dynamic activity that involves the healthy interaction of these cells and tissues along the entire length of the implant.

[Implant rehabilitation of distal mandibular atrophy using a blade implant]. / Rehabilitation implantaire des atrophies mandibulaires distales par l'implant ramique.

After a brief revision of the anatomy of the posterior mandible and its natural resorption pattern, the ramus plate-form implant would be the implant of choice for the rehabilitation of this region. This "site specific" implant is inserted on the top of the crest and superficially impacted within the residual alveolar bone at the distal segment of the horizontal branch and guided to climb parallel to the anterior aspect of the ascending ramus. Its form and specific dimensions are perfectly compatible with the frequently limited quantity of available bone above the nerve canal in patients with advanced atrophy of the posterior mandible. It provides a predictable abutment for the implant-supported or dento-implant-supported prostheses of the posterior mandible.

[Blade implants: new ideas]. / Les implants-lames: nouvelles conceptions.

It is often thought that the insertion of laminar implants is imprecise, poorly standardized, and consequently, does not favour integration into the bone. We have been able to confirm that laminar implants are integrated into the bone in an experimental dog model and in pathology studies. To avoid the inconveniences often encountered, we developed a new concept laminar implant. Characteristics of the implant Body thickness = 1.2 mm; length = 20 and 16 mm; height of body = 6 or 8 mm; shaft : 3.25 mm diameter. The most important feature is that the upper part of the sheath around the collar does not overrun the upper border of the body by more than 1 mm. The total height is thus 7 or 9 mm. Insertion technique Discs are mounted on the counter-angle at increasing thicknesses. The third and last disc is 1.2 mm thick and has a radius corresponding to the 7 or 9 mm implant. The mandibular canal is perfectly protected with this technique. Indications Thin crests in the molar region of the mandible. Minimal bone between the crest and the mandibular canal. Subsinus implantation.

Fractures of hydroxyapatite-coated blade implants connected with natural teeth. A histological study using SEM, light microscopy, and an image processing system.

A clinical study was conducted of 59 patients treated with 78 hydroxyapatite (HA)-coated blade implants from August 1986. Five implants in 5 patients were broken at the neck portion, and one implant in one patient was removed from the jaw bone. The histological findings around a broken implant which was removed from the mandible are presented. These sections showed good adaptation of the bone to the implant without a fibrous layer. Histomorphometric evaluation of bone-to-implant contact showed 73.5%. The scanning electron microscopy image of the fractured surface revealed a fatigue fracture. The suspected cause of the fracture was stress concentration at the cervix portion, because of excessive mobility or deleterious change of abutment teeth. Consequently, the osseointegration/biointegration implants should not be connected with natural teeth.

Types, uses, and evaluation of the plate-form implant.

Plate-form blades have shown a high rate of success over their 25+ years of service. Contributing to their longevity is the design of the implant, which transfers the applied forces over a large area of bone. Three types of implants are being considered: (1) the Ramus Blade, designed for the body and ramus region of the mandible; (2) the Ramus Frame, designed for the totally edentulous mandible with moderate to severe bone atrophy; and (3) the single-tooth replacement, an implant for single or multiple tooth loss. Both 316-L stainless steel and titanium metal types have been used to fabricate each implant type. Blades are, in the author's opinion, the most universal of the implants used today, for they are utilized in so many variable bone widths and heights. Besides being in service for periods of up to 27 years, they are patient-acceptable in terms of comfort, function and minimal maintenance.

A light microscopy, scanning electron microscopy, and laser scanning microscopy analysis of retrieved blade implants after 7 to 20 years of clinical function. A report of 3 cases.

The aim of the present study was to evaluate by means of light microscopy, scanning electron microscopy, and laser scanning microscopy the thin ground sections of blade implants retrieved after 7 to 20 years of clinical function. Microscopic examination revealed that most of the implant surface had an intimate contact with compact lamellar bone tissue. Higher magnifications revealed the presence of a gap (1 to 5 mu) interposed between bone and implant. Many osteocytes were near the implant surface and, in many instances, osteocyte canaliculi, running from the lacunae towards the implant surface, were seen. Structures similar to bone reversal lines were observed at the edge of the bone side of the interface. The bone-titanium region is probably an area of dynamic biological activity.

[Rehabilitation of the dentition using intraosseous blade implants]. / Príspevek k rehabilitaci chrupu pomocí nitrokostních cepelkovych implantátu.

Intraosseous blade vent implants extend hitherto existing clinical methods of prosthetic treatment of some conditions of defective teeth by new possibilities. It is a method which can produce satisfactory and long-term results. One of the prerequisites is, however, that generally valid and local limitations for indication of the implantation will be respected, that the implantation will be implemented by reliable surgical technique along with high standard prosthetic treatment which in the course of recovery will carry the implant to its functional period. Results of our investigations revealed unequivocally that the use of implants with a low or predominantly low intraosseous part leads in the majority to unsatisfactory results of implantations.

[Ultrasound instruments for surgical purposes--technical aspects and selected areas for use]. / Ultraschallinstrumente für chirurgische Zwecke--Technische Aspekte und ausgewählte Anwendungsgebiete.

Surgical instruments simulated to oscillate by means of low-frequency performance ultrasound are particularly useful for specific fields of application. A survey describes the technical principle of action and the development work carried out at the Technical University of Karl-Marx-Stadt in the GDR to produce ultrasound instruments for tumour extraction and aspiration, for the insertion of stomatological leaf implants, for percutaneous lithotrips of kidney stones and for the surface treatment of septic wounds.

Veterans Administration Cooperative Dental Implant Study--comparisons between fixed partial dentures supported by blade-vent implants and removable partial dentures. Part II: Comparisons of success rates and periodontal health between two treatment modalities.

Five Veterans Administration centers have participated in a study to determine whether fixed partial dentures (FPDs) supported by blade implants offer an acceptable substitute for mandibular unilateral or bilateral distal-base extension removable partial dentures (RPDs). The study design and methodology have been described in Part I. A total of 232 patients received comprehensive dental care including RPDs for 118 patients and FPDs for 114. Prespecified criteria determined treatment failures. During the 60-month period, treatment failures occurred in 19 FPD patients and 30 RPD patients. Ten FPD failures occurred before and nine after the FPD insertion. Five RPD failures were caused by abutment tooth loss and 25 for not using the RPD while eating. Life table analysis showed 5-year success rates of 84.2% for the FPD and 74% for the RPD. The 17.9% higher FPD success rate in Kennedy class II patients was both statistically and clinically significant. Excluding the 10 early failures, the 5-year FPD success rate was 91.5%. Of the 170 attempted implants, 26 failed, including 12 before the FPD fabrication. Radiographic assessments by a panel of three judges showed no bone deterioration during baseline to 60 months in 29.6%, slight in 25.4%, moderate in 15.9%, marked in 27%, and severe deterioration in 2.1% of the implant posts.