Jaw Defects Research Articles

Osseous regeneration in the jaws using demineralized allogenic bone implants

Osseous defects of the jaws following trauma, congenital deformity or pathology may show poor osteogenesis and the affected area may never be completely replaced by bone or will show alveolar height loss. The purpose of the present study was to evaluate the effect of allogenic bone implants (ABI) on the osteogenesis of jaw defects. Fifty-two patients (27 males, 25 females) with cystic lesions of the jaws were randomly divided into two groups: Group A underwent enucleation and packing with adsorbable gelatine sponge. Group B underwent enucleation and grafting with ABI. Both groups were evaluated radiographically. The height of the alveolar process was measured directly on the radiography. The density was measured with a digital densitometer. In Group A, the mandibular height at 6, 12 and 24 months postoperatively was 88%, 80% and 78% of the preoperative heights, respectively. In Group B, the heights were 95%, 93% and 90%, respectively. These differences were significant (P < 0.05-0.01). The density in Group B was significantly greater (P < 0.05-0.01) than in Group A at 6 and 12 months postoperatively. The difference at 24 months was not significant. On the basis of these findings, it can be concluded that ABI grafting of jaw defects enhances osteogenesis and prevents alveolar height loss in the mandible. ABI represent an encouraging alternative to autogenous bone grafting.

Effect of decalcified freeze-dried bone allograft on the healing of jaw defects after cyst enucleation.

Effect of decalcified freeze-dried bone allograft on the healing of jaw defects after cyst enucleation.

Effect of decalcified freeze-dried bone allograft on the healing of jaw defects after cyst enucleation

Purpose: This study radiographically evaluated the changes that occur in jaw defects after enucleation of cysts and either grafting with demineralized freeze-dried bone allograft (DFDBA) or packing with absorbable gelatine sponge (Gelfoam). Patients and Methods: Thirty-two patients (14 males, 18 females) with cystic lesions of the jaws were divided into two groups. Group A underwent enucleation and bone grafting with DFDBA. Group B underwent enucleation and packing with Gelfoam. Both groups were evaluated radiographically before surgery, immediately postoperatively, and 6, 12, 24, and 36 months postoperatively. The density of the area was measured with a digital densitometer. Results: The density in group A was significantly ( P < .05 to .01) greater than in group B at 6 and 12 months postoperatively. The difference at 24 months was not significant. Group A reached density levels at 6 months that were reached by group B at 12 months. Conclusion: The findings demonstrate that decalcified freeze-dried bone allograft enhances bone healing in jaw defects after cyst removal.

Bone-Graft Surgery

Bone-Graft Surgery

Clinical Evaluation of &beta;-TCP Grafting to Osseous Defects in Jaws

Clinical Evaluation of &beta;-TCP Grafting to Osseous Defects in Jaws

The use of fresh frozen allogeneic bone for maxillary and mandibular reconstruction

The use of fresh frozen bone (FFB) alone, or in combination with autogenous bone (AB), for bony augmentation of the maxilla and mandible in preparation for dental reconstruction with endosseous implants has been studied. Ten patients received FFB±AB for augmentation of a severely atrophic mandible ( n=6) or for reconstruction of a jaw defect secondary to trauma or tumor resection ( n = 4). Average follow-up was 26.3 ± 5.4 months. At the time of implant placement, the bone grafts were found to be firm in consistency, well incorporated, and well vascularized in all 10 patients. Twenty-nine endosseous implants were placed an average of 8.3±3.1 months following bone grafting. One implant failed and was replaced, and one implant remains buried as a nonfunctional unit. All patients have been restored prosthetically by means of 28 of the 29 implants. This preliminary study indicates that FFB may be used alone or in combination with autogenous bone for augmentation or reconstruction of the atrophic maxilla and mandible. The resultant ridge is adequate to support loaded endosseous implants. A potential disadvantage is the minimal risk of disease transmission.

Bridging lower jaw defects with AO plates: comparison of THORP and 3-DBRP systems

Two reconstruction plate systems, the 3-dimensionally-bendable reconstruction plate (3-DBRP) and the titanium hollow screw and reconstruction plate (THORP) were compared in clinical use. Fewer complications in patients were observed with the THORP system than with the 3-DBRP system. In general, both systems are reliable and approved. In cases of extensive defects, however, the THORP system appears to be more effective because of its larger size and its better anchorage.

Short-term behaviour of two similar active glasses used as granules in the repair of bone defects

The bioactivity of two similar vitreous materials used in the form of granules of ‘critical’ size was investigated in bone defects in jaws of two sheep. The granules consisted of Hench's Bioglass® and another glass with the same chemical composition made in Italy. Two months after implantation, the sheep were killed and elemental analyses carried out on sections of the embedded jaws. The microanalyses for both the glasses showed a diffusion from the granules towards the surrounding tissue of silicon and sodium, and an inverse diffusion (from the surrounding tissue towards the granules) of calcium and phosphorus. The degradation for the Italian glass was slower than for the Bioglass. No significant osteoinduction was seen after that time at the interface of the glass granules or in the bone pocket.

Prosthesis Serviceability for Acquired Jaw Defects

Patients with acquired jaw defects treated with prostheses present variable prosthesis longevity due to variable factors that influence the tissue foundation anatomically and physiologically supporting the prosthesis. Prosthesis serviceability is unpredictable or limited in longevity. Multiple prostheses and sequential prostheses interrelated are often indicated to effectively rehabilitate patients with acquired jaw defects.

Light-cured hollow obturators

Obturators used in the rehabilitation of large defects of the upper jaw should be easily made to produce a comfortable and stable prosthesis. This goal has been difficult to achieve by using traditional materials and techniques. This article describes a technique to overcome these problems by using a visible light-cured resin. Results indicate that resultant obturators are easily and quickly constructed, and provide a light, comfortable, and well-tolerated prosthesis.

Rigid Internal Fixation and Vascularized Bone Grafting in Mandibular Reconstruction

The technique of mandibular reconstruction utilizing rigid internal fixation and vascularized bone grafts has been described. This type of repair should be considered in all patients undergoing mandibular resection for head and neck malignancies. Although no ideal method of reconstruction has yet been described, it appears that rigid internal fixation combined with vascularized bone grafts most satisfactorily fulfills the requirements associated with reconstruction of jaw defects.

Mandibular reconstruction with the titanium hollow screw reconstruction plate (THORP) system: evaluation of 62 cases.

The titanium hollow screw reconstruction plate (THORP) system for reconstruction of lower jaw defects provides a functional stable fixation and is used as a long-term or permanent implant in tumor surgery and in traumatology. The rigid fixation of the head of the screw to the plate, avoiding unphysiologic loads to the bone underneath the plate, and the titanium plasma-coated perforated hollow screws, enabling the development of direct bone-titanium contact as well as the ingrowth of bone into the lumen and perforations, are the major advantages of this system compared to conventional systems. The different surgical methods, such as preservation of the condylar process with only two screws, intraoperative freely adjustable condylar prosthesis, lingual application of the plate, and primary bone transplantation, are described. The evaluation of 62 patients reconstructed with the THORP system between 1981 and 1986 revealed no plate loosening, even in irradiated bone, and showed satisfactory aesthetic and functional results.

Titanium-coated hollow screw and reconstruction plate system for bridging of lower jaw defects: Biomechanical aspects

The biomechanical and design principles of the titanium hollow screw and reconstruction plate (THRP) system are described. Physiologically advantageous load transmission, a biocompatible implant material with sufficient strength and a surface structure favorable to biological stabilization are discussed. The design of the fixation between the cross-split screwhead and the plate hole gives a rigid and stable plate fixation even without contact between plate underside and bone. Blood perfusion and bone strength will therefore not be affected. Full functional loading with only 2–3 fixation screws for each plate end is possible. Further technical advantages of the THRP system are the possibility of lingual plate application and integration of a three-dimensional adjustable condylar prothesis.

Homologous cancellous bone grafts for large jaw defects caused by bone cysts

For more than 10 years homologous bone stored at -20 degrees C has been used to fill large bone cavities after cystectomy. This article outlines the principles of collecting, storing, and preserving the homograft, presents special aspects of the surgical technique, and reports long-term results.

The lingual application of a reconstruction plate: A new method in bridging lower jaw defects

The bridging of mandibular defects following tumor resection presents special problems. This stimulated us to look for a stable implant fixation method, particularly for use in irradiated tissues. We therefore developed the titanium hollow screwreconstruction plate system (THRP system) and have used it successfully during the last four years. I-4 The application of the THRP system as well as other conventional reconstruction plates is done on

下がく骨骨欠損部の骨再生に関する実験的研究 特に骨膜の影響について

We often encounter the cases in which periosteum with bone defects cannot be preserved because of surgical resection of tumors or injuries. Bone and periosteum transplantation are generally accepted for repair in these cases. However, there are a few reports that experimental healing process of bone defects without periosteum in the mandibular bone has been observed. This investigation was undertaken to study healing process of the amputation stump in the mandibular jaw defects of the adult dogs in such experimental situations as lack of the ability of bone formation by periosteum and bone transplantation. Thirty-nine adult dogs were used in this study. Experimenal bone defects with spacing of 10 × 15 mm were made in the mandibular bone.They were divided into two groups for comparison:A) The defect was covered with silicon sheet after preserving the inferior alveolar artery and vein.B) The defect was left uncovered after preserving the inferior alveolar artery and vein. Process of bone healing was observed for 7 months. Four different fluorochromes were administered in order to estimate activity and the source of bone formation for the period. Biopsy specimens for light microscopy and fluorescence microscopy were obtained, and radiographic examination was also performed.The results obtained were as follows:1) The bone repair in one of A group began in 5 months. However, bone formation was found in one-half of the number of cases in A group and the outline of the mandibular bone was repaired to almost normal size in 7 months.2) The bone formation in B group terminated in 3-5 months, but a small concavity in the normal outline of the mandibular bone could be seen after 7 months.When the inferior alveolar artery and vein are preserved, the inserted silicon sheet prevents formation of the fibrous scar tissue and pressures from the surrounding tissue. Therefore, bone formation fills up bone defects without the bone graft and/or preservation of periosteum.

Use of the titanium-coated hollow screw and reconstruction plate system in bridging of lower jaw defects

Clinical results obtained with hollow titanium screws and reconstruction plates in the bridging of mandibular bone defects of 17 patients are described. Following implantation the newly forming bone establishes direct contact with the sprayed titanium surface of the screw and the underside of the plate and permeates the screw. The stability of anchorage therefore increases with the duration of implantation. The reconstruction system also allows salvaging of small fragments such as the condyloid process. The adjustable, individually shaped, mandibular condylar prosthesis permits precise restoration of articular guidance on the reconstructed side while preventing incorrect loading of the opposite joint. The clinical results confirm the recently published findings from animal studies.

Treatment of jaw defects with demineralized bone implants

Demineralized allogeneic bone implants were used for the treatment of 50 jaw defects. Thirty-five implants were placed within skeletal sites, and 15 implants were placed for contour augmentation. Follow-up evaluation has continued for up to two years, and healing was confirmed by physical examination, radiography, and biopsy when appropriate. The complication rate was no greater than that for conventional bone grafts.

Evaluation of ossification in jaw defects by radio-nuclide imaging.

The uptake of the bone-seeking radiopharmaceutical 99mTc-MDP in defects of the mandibula was quantitated from scintigraphic images. Activity ratios were calculated by means of ROI-technique. The four selected regions contained two control regions and two with mandibula defects. One defect was filled with a fibrin bonding agent and one remained unfilled. The time course of the ratios showed a significant higher uptake of 99mTc-MDP in the region of the filled defect in comparison with the unfilled defect. The measurement of the residual defect areas from histological sections prepared 18 weeks after introduction of the defects confirmed the much more intensive ossification in the filled defects which could also be derived from the evaluation of the scintigrams. The results indicate that it is possible to follow up osseous repair by quantitative evaluation of scintigraphic images.

Restoration of mandibular jaw defects in the rabbit by subperiosteally implanted Teflon® mantle leaf

The present investigation was undertaken to study the healing pattern of mandibular jaw defects where one or two lateral bone walls were missing. The bone regeneration between contralateral defects was compared; in one jaw the defects were covered with perforated mantle leaf of Teflon®, in the contralateral jaw the defects were left uncovered. Eighteen adult white rabbits were used for the study. Experimental standardized defects with respectively one and two lateral bone walls missing were made in the mandibular base area. On one side the defects were covered with subperiosteally implanted perforated mantle leaf before suturing the soft tissue. The bone healing was followed during 52 weeks and three different fluorochromes were administered at 2, 4, 6, 12, 26 and 52 weeks in order to estimate the activity and source of the bone regeneration during different time periods. Specimens were obtained both for paraffin sections and ground sections. Light microscopic and fluorescence microscopic examinations were made of the sections. Healing of defects covered with subperiosteally implanted Teflon mantle leaf showed almost complete bone regeneration of both two-wall defects and three-wall defects, whereas in the contralateral jaws the uncovered two-wall bone defects showed incomplete healing of the defects with a central part of fibrous connective tissue. The three-wall defects without mantle-leaf cover, on the contrary, healed with almost complete bone regeneration; only a small concavity in the normal outline of the bone could be seen. It seems as if subperiosteally implanted mantle-leaf cover prevents formation of a fibrous scar tissue and allows the bone regeneration to proceed and fill up the two-wall defects completely.