Strain driven fast osseointegration of implants

Background

Although the bone's capability of dental implant osseointegration has clinically been utilised as early as in the Gallo-Roman population, the specific mechanisms for the emergence and maintenance of peri-implant bone under functional load have not been identified. Here we show that under immediate loading of specially designed dental implants with masticatory loads, osseointegration is rapidly achieved.

Methods

We examined the bone reaction around non- and immediately loaded dental implants inserted in the mandible of mature minipigs during the presently assumed time for osseointegration. We used threaded conical titanium implants containing a titanium2+ oxide surface, allowing direct bone contact after insertion. The external geometry was designed according to finite element analysis: the calculation showed that physiological amplitudes of strain (500–3,000 ustrain) generated through mastication were homogenously distributed in peri-implant bone. The strain-energy density (SED) rate under assessment of a 1 Hz loading cycle was 150 Jm-3 s-1, peak dislocations were lower then nm.

Results

Bone was in direct contact to the implant surface (bone/implant contact rate 90%) from day one of implant insertion, as quantified by undecalcified histological sections. This effect was substantiated by ultrastructural analysis of intimate osteoblast attachment and mature collagen mineralisation at the titanium surface. We detected no loss in the intimate bone/implant bond during the experimental period of either control or experimental animals, indicating that immediate load had no adverse effect on bone structure in peri-implant bone.

Conclusion

In terms of clinical relevance, the load related bone reaction at the implant interface may in combination with substrate effects be responsible for an immediate osseointegration state.     

Translational research for injectable tissue-engineered bone regeneration using mesenchymal stem cells and platelet-rich plasma: from basic research to clinical case study

Translational research involves application of basic scientific discoveries into clinically germane findings and, simultaneously, the generation of scientific questions based on clinical observations. At first, as basic research we investigated tissue-engineered bone regeneration using mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) in a dog mandible model. We also confirmed the correlation between osseointegration in dental implants and the injectable bone. Bone defects made with a trephine bar were implanted with graft materials as follows: PRP, dog MSCs (dMSCs) and PRP, autogenous particulate cancellous bone and marrow (PCBM), and control (defect only). Two months later, dental implants were installed. According to the histological and histomorphometric observations at 2 months after implants, the amount of bone-implant contact at the bone-implant interface was significantly different between the PRP, PCBM, dMSCs/ PRP, native bone, and control groups. Significant differences were also found between the dMSCs/PRP, native bone, and control groups in bone density. These findings indicate that the use of a mixture of dMSCs/ PRP will provide good results in implant treatment compared with that achieved by autogenous PCBM. We then applied this injectable tissue-engineered bone to onlay plasty in the posterior maxilla or mandible in three human patients. Injectable tissue-engineered bone was grafted and, simultaneously, 2-3 threaded titanium implants were inserted into the defect area. The results of this investigation indicated that injectable tissue-engineered bone used for the plasty area with simultaneous implant placement provided stable and predictable results in terms of implant success. We regenerated bone with minimal invasiveness and good plasticity, which could provide a clinical alternative to autogenous bone grafts. This might be a good case of translational research from basic research to clinical application.     

Spinal implants and radiation therapy: the effect of various configurations of titanium implant systems in a single-level vertebral metastasis model

BACKGROUND: The combination of surgery and radiation therapy is a common clinical practice in the treatment of spinal tumors. Although it is known that metallic implants disturb radiation therapy beams, it is not known what kind of dose distributions appear with spinal irradiation in the presence of a spinal implant. The aim of the present study was to investigate the effect of various spinal implant constructs on the dose of radiation delivered to the spinal canal in a single-level metastasis model. METHODS: We performed four spinal implant reconstructions on standard sawbones spine models: posterior instrumentation without anterior column reconstruction, posterior instrumentation with anterior column reconstruction with use of a titanium cage, anterior instrumentation with anterior column reconstruction with use of a titanium cage, and anterior instrumentation with anterior column reconstruction with use of chest tubes filled with bone cement. Irradiation with two different radiation therapy units (a cobalt-60 teletherapy unit and a linear accelerator) was performed twice for each model in a posterior-to-anterior direction, and thermoluminescent dosimeters were used to measure the dose changes in the anterior, middle, and posterior portions of the spinal canal. RESULTS: Compared with the sawbones-only model, the posterior instrumentation reconstructions resulted in a 5% to 7% decrease in the radiation dose delivered to the spinal canal with both radiation therapy units, whereas the anterior instrumentation reconstructions resulted in a 1% decrease in the dose delivered with the linear accelerator unit and a < or = 2% increase in the dose delivered with the cobalt-60 teletherapy unit. When thermoluminescent dosimeters in the middle of the spinal canal were evaluated individually, anterior instrumentation with anterior column reconstruction with use of bone cement-filled chest tubes resulted in a 5.5% increase in the radiation dose delivered with the cobalt-60 teletherapy unit, whereas all of the other instrumentation models resulted in a <1% disturbance in the radiation dose delivered with both radiation therapy units. CONCLUSIONS: The posterior instrumentation systems did not result in the delivery of an increased dose of radiation to the spinal cord, suggesting that current radiation therapy regimens may be performed without additional harm. The anterior instrumentation systems also appeared to be relatively safe when irradiation was performed with the linear accelerator unit. However, when irradiation was performed with use of the cobalt-60 teletherapy unit, there was an increase in the dose of radiation delivered to the spinal canal in the presence of the anterior instrumentation systems, particularly the anterior column reconstruction with use of bone cement-filled chest tubes. These dose-perturbation characteristics might be important to consider during the calculation of radiation therapy protocols for patients who are going to receive high doses or recurrent treatments that would reach the tolerance limits of the spinal cord.     

Histologic and histomorphometric analysis of an immediately loaded implant retrieved from man after 14 months of loading

OBJECTIVE: The aim of this study was a histologic and histomorphometric analysis of the peri-implant tissue reactions and the bone/titanium interface in an immediately loaded titanium implant inserted in a soft bone site and retrieved, in man, after a 14-month loading period. METHODS. A 65-year-old patient presented with a partial edentulism in the left posterior mandible. The patient was rehabilitated with three dental implants inserted in the left first, second, and third molar sites. All these implants were immediately put into a nonfunctional loading mode and joined with the other implants that supported the temporary restorations. After 14 months, the most distal implant and surrounding tissues were retrieved because of psychological problems of the patient. RESULTS: Newly formed, strongly stained, compact, mature cortical bone with few marrow spaces was observed around the implant, especially in the coronal portion. No inflammatory infiltrate was present around the implant. No gaps or dense fibrous connective tissue were found at the bone/metal interface. No apical epithelial migration was found. In the cortical portion, bone remodeling areas were present with many newly formed Haversian canals. Only in a few areas of the interface was it possible to observe an osteoblast rim. In the apical portion, newly formed bone trabeculae were present; these were composed mostly by woven bone, and only a small quantity of preexisting lamellar bone was present. Histomorphometric evaluation showed that the bone/implant contact percentage was 72.6% (+/-2.7%). CONCLUSIONS: We found that, in immediately loaded implants inserted in soft tissue sites, it was possible to find a high percentage of bone-to-implant contact and that osseointegration was maintained for more than 1 year. This fact could be partly explained with the use of an implant with a rough surface.     

Permanent iodine-125 implant and external beam radiation therapy for the treatment of malignant brain tumors.

Survival data of 114 patients treated for malignant brain tumors with 125I interstitial radiation therapy at Henry Ford Hospital, Detroit, Mich. (1986-1990), are presented. The first 64 patients were treated with temporary 125I implants with a total prescribed dose of 60 Gy at a dose rate of 40 cGy/h. In order to reduce the risk of injury to the surrounding normal tissue associated with high-dose brachytherapy, a new approach was initiated using permanent implants with a lower dose rate; 50 patients were treated after surgical resection with permanent implantation of 125I seeds at a lower dose rate of 4-7 cGy/h, with a total dose of 10,000-12,000 cGy, and concurrent external radiation therapy of 5,000 cGy. The rationale of this protocol was to increase the effectiveness of the low-dose-rate implant by a concurrent 'daily' boost of external radiation, thus inhibiting the proliferation of tumor cells during the protracted low-dose radiation treatment. Survival was compared between groups with permanent and temporary implants in terms of effectiveness in tumor control as well as impact on clinical condition. Low-dose-rate implant with concurrent external radiation therapy seems to offer the best chance for long-term survival without deterioration in the clinical condition.     

The bisphosphonate ibandronate accelerates osseointegration of hydroxyapatite-coated cementless implants in an animal model

Background There is evidence that bisphosphonates can improve fixation of cementless metal implants by enhancing the extent of osseointegration. The current preclinical study examined whether the nitrogen-containing bisphosphonate ibandronate can accelerate this process, resulting in early achievement of secondary stability and sealing of the bone–implant interface to prevent wear debris migration. Methods The study was conducted on 88 female Sprague-Dawley rats in which uncoated titanium and hydroxyapatite-coated titanium implants were surgically inserted into the medullary canal of each femur. The animals were randomly assigned to receive subcutaneous treatment with 1.0, 2.5, or 5.0 μg/kg per day ibandronate or saline solution as a control. The extent of osseointegration expressed by the osseointegrated implant surface was quantified by histomorphometry at eleven time points during the study period. To determine the time course of osseointegration, the data were expressed using third-order polynomial regression analysis. Results For hydroxyapatite-coated implants, the highest dose of ibandronate (5 μg) reduced the time for a sufficient implant fixation of 60% osseointegrated implant surface to 18 days compared to 38 days in the control group. This reduction of 20 days (52.6%) represents a halving in the time required for sufficient osseointegration of the implant. For hydroxyapatite-coated implants and low-dose ibandronate application (1 μg, 2.5 μg) and for uncoated titanium implants, acceleration of osseointegration was not observed in any of the study arms. Conclusion Continuous treatment with 5 μg/kg per day ibandronate is potent in accelerating osseointegration of hydroxyapatite-coated implants. As a result, improved early secondary stability and prevention of wear debris migration by the sealing of the implant–bone interface can be expected, therefore prolonging the long-term survival of the implant.     

In vitro and in vivo performance of a novel surface treatment to enhance osseointegration of endosseous implants.

OBJECTIVE: This article shows the in vitro and in vivo characterization of a new biomimetic treatment developed to enhance the osseointegration of titanium dental implants. STUDY DESIGN: A novel biomimetic treatment of titanium was developed. Its physicochemical properties and biologic and in vivo performance were considered and studied. Mineralization capability was assessed by soaking test in simulated body fluid solution, and cytocompatibility was assessed using osteoblast-like MG63 cell culture. Histomorphometric analysis was performed at 3 time points using a sheep animal model. RESULTS: In vitro tests confirmed the biomimetic potential of the considered novel treatment. Histomorphometric analysis indicated its potential for rapid and good-quality osseointegration. CONCLUSION: The in vitro and in vivo test results indicated that the proposed novel treatment possesses a significant potential to increase the rate of osteointegration of titanium for endosseous dental implants.     

Outcome of patients treated with cobalt and 6 MV in head and neck cancers.

BACKGROUND: Since 1992, we have been using a 6-MV linear accelerator instead of a cobalt machine. The aim of the study is to evaluate the impact of this on neck control, particularly on postoperative patients in which subcutaneous tissues are at risk. METHOD: A retrospective study including all of 1,452 consecutive patients treated by definitive or postoperative radiotherapy between 1989 and 1997. All stages and subsites of the head/neck were included. Local and neck control were evaluated by the Kaplan Meier method, and comparisons were made between the cobalt and the 6-MV subgroups with a subsequent Cox analysis. For neck control analysis, the postoperative patients were divided in low and high risk (extracapsular extension [ECE], >two nodes, or T4). RESULTS: Radical radiotherapy: A better local control (LC) is observed with 6 MV than with cobalt, but neck control was similar. Postoperative radiotherapy: A better LC is observed with 6 MV. In high-risk patients, the neck control was higher for the cobalt group (79%) vs 60% for the 6-MV group (p = .09 and .03 in a Cox model). CONCLUSION: In postoperative patients at high risk for neck relapse, cobalt seems to give a better neck control. We are currently doing a prospective study in which a bolus is added for half the treatment when patients at high risk for neck relapse are treated with 6 MV.     

Does the presence of an implant including expander with internal port alter radiation dose? An ex vivo model

BACKGROUND:

There is a lack of literature examining the dosimetric implications of irradiating breast implants and expanders with internal ports inserted at the time of mastectomy.

OBJECTIVE:

To determine whether the presence of breast expanders with port in saline or silicone implants affect the dose uniformity across the breast when irradiated with various photon and electron energies.

METHODS:

One tissue-equivalent torso phantom with overlying tissue expanders in saline or silicone implants were irradiated using tangential fields with 6 MV and 18 MV photons and 9 MeV and 12 MeV electrons. All dose measurements were performed using thermoluminescent dosimeters (TLDs). The TLDs were arranged around the port and the perimeters of either the expander, or saline or silicone implant. Comparisons of measured radiation doses, and between the expected and measured doses of radiation from the TLDs on each prosthesis, were performed. Data were analyzed using two-tailed t tests.

RESULTS:

There were no differences in TLD measurements between the expander and the saline implant for all energy modalities, and for the expected versus actual measurements for the saline implant. Higher than anticipated measurements were recorded for a significant number of TLD positions around the silicone implants.

CONCLUSIONS:

Radiation doses around saline implants or expanders with internal port were unaltered, whereas dose recordings for silicone implants were higher than predicted in the present laboratory/ex vivo study.     

Woven bone formation around implants and the effect of bacterial infection.

Several implant materials used in dental and orthopedic surgery were placed in rat tibial bones to study their effects on mineralization. The implants consisted of bone bonding and non-bonding materials. Changes in mineralization were defined by morphometric analysis of matrix vesicle distribution at the implant interface and in normal bone healing following marrow injury. Bone-bonding materials induced an increase in matrix vesicle activity. This finding was supported by study of the biochemical changes in the same model that manifested high correlations to the morphometrical observations with regard to enhancement or delay of primary mineralization. In addition, the study of healing using nuclear methods indicated that implants alter bone healing as shown by the different uptakes of 99mTc and 32P in the different bone compartments. Decreased 32P uptake by the organic phase in the presence of bone-bonding implants suggested that cleavage of 99mTc-MD32P into its technetium and methylene diphosphonate moieties was inhibited by administration of implants. Further studies on the effect of bacterial infection on the peri-implant tissues revealed a decrease in woven bone formation due to infection.     

Effects of surface roughness of titanium implants on bone remodeling activity of femur in rabbits

We investigated the bone remodeling activity on titanium implants with different surface roughnesses using a confocal laser scanning microscope (CLSM). Two kinds of implants were used, the machined smooth-surfaced titanium and the plasma-sprayed rough-surfaced titanium. These implants were randomly inserted in a rabbit's femur from the lateral aspect of the diaphysis bicortically. Rabbits were killed at 6, 16, and 42 weeks after surgery. The implant-bone blocks were embedded in polyester resin, and were prepared to make undecalcified ground sections. Histomorphometric analyses were performed at the cortical bone-implant interface using the image obtained by CLSM. Percentages of direct bone-implant contact and bone volume (BV/TV) around the implant was greater in rough-surfaced titanium compared with the smooth-surfaced titanium at 42 weeks after implantation. On the contrary, the eroded surface (ES/BS) appeared to be less in the rough-surfaced titanium than in the smooth-surfaced titanium at 6 weeks after implantation, but thereafter, no difference was found between the two kinds of implants. Mineralizing surface (MS/BS) and mineral apposition rate (MAR) showed no significant differences throughtout the experimental period. These results indicate that increased bone volume in the rabbits of rough-surfaced titanium implants is due to less remodeling activity during the early stage after implantation compared with the smooth-surfaced implants. The surface roughness of titanium is one factor which helps in determining the balance between bone formation and resorption of remodeling at the interface of the bone implants.     

Analysis of complications following alveolar distraction osteogenesis and implant placement in the partially edentulous mandible.

OBJECTIVE: The purpose of this retrospective study was to evaluate complications before, during, and after vertical alveolar distraction osteogenesis and to assess the survival rate of dental implants placed in distracted bone. STUDY DESIGN: In a consecutive series, 37 patients with 45 alveolar ridge deficiencies of the partially edentulous mandible were treated with 14 intraosseous and 31 subperiosteal distraction devices. Seventy-two dental implants could be placed at the time of distractor removal and 21 implants at a second stage. RESULTS: Complications associated with the distraction procedure affected 75.7% of patients. The majority of complications were of minor nature with the exception of fractures of basal bone (n = 3), fracture of transport segment (n = 1), breakage of distractor (n = 1), and severe mechanical problems (n = 3). Eleven secondary grafting procedures were necessary to allow the placement of dental implants. Implant survival was 95.7% (mean postloading follow-up: 35.7 months). CONCLUSION: Vertical alveolar distraction osteogenesis is not an uncomplicated procedure; however, long-term survival of dental implants inserted into distracted areas is satisfactory.     

Thermodynamic effects of laser irradiation of implants placed in bone: an in vitro study

Lasers have been proposed for various applications involving dental implants, including uncovering implants and treating peri-implantitis. However, the effect of laser irradiation on the implant surface temperature is only partially known. The aim of this pilot study was to determine the effect of irradiation with diode, carbon dioxide, and Er:YAG lasers on the surface temperature of dental implants placed in bone, in vitro. For this study, one dental implant was placed in a bovine rib. A trephine bur was used to create a circumferential defect to simulate peri-implantitis, and thermocouples were placed at the coronal and apical aspect of the implant. The implant was irradiated for 60 s using four different lasers independently and change in temperature as well as time to reach a 10 °C increase in temperature were recorded. There was wide variability in results among the lasers and settings. Time for a 10 °C increase ranged from 0.9 to over 60 s for the coronal thermocouple and from 18 to over 60 s for the apical thermocouple. Maximum temperature ranged from 5.9 to 70.9 °C coronally and from 1.4 to 23.4 °C apically. During laser irradiation of dental implants, a surface temperature increase beyond the “critical threshold” of 10 °C can be reached after only 18 s.     

Postradiation dental extractions: a review of the literature and a report of 72 episodes

This report outlines our experiences involving 72 episodes of postradiation dental extraction over an 11-year period. Bone exposures of 3 months or longer developed following 16 of the 72 postradiation extraction episodes (22%). The necrosis rate in the mandible was 29% (13 of 45) and in the maxilla was 11% (3 of 27). The risk of bone necrosis increased when the dose to bone exceeded 6,500 rad, and when 75% or more of the body of the mandible was within the radiation treatment volume. Five of the 13 mandibular bone necroses precipitated by postradiation extractions eventually required radical resection of the affected portion of the mandible. The remaining eight mandibular episodes healed with conservative measures. When possible, given the two above conditions, root canal therapy rather than dental extraction should be employed to resolve mandibular dental infection within the radiation field after radiotherapy.     

Osseointegrated Titanium Implants: Requirements for Ensuring a Long-Lasting, Direct Bone-to-Implant Anchorage in Man

A total of 2895 threaded, cylindrical titanium implants have been inserted into the mandible or the maxilla and 124 similar implants have been installed in the tibial, temporal or iliac bones in man for various bone restorative procedures. The titanium screws were implanted without the use of cement, using a meticulous technique aiming at osseointegration-a direct contact between living bone and implant. Thirty-eight stable and integrated screws were removed for various reasons from 18 patients. The interface zone between bone and implant was investigated using X-rays, SEM, TEM and histology. The SEM study showed a very close spatial relationship between titanium and bone. The pattern of the anchorage of collagen filaments to titanium appeared to be similar to that of Sharpey's fibres to bone. No wear products were seen in the bone or soft tissues in spite of implant loading times up to 90 months. The soft tissues were also closely adhered to the titanium implant, thereby forming a biological seal, preventing microorganism infiltration along the implant. The implants in many cases had been allowed to permanently penetrate the gingiva and skin. This caused no adverse tissue effects. An intact bone-implant interface was analyzed by TEM, revealing a direct bone-to-implant interface contact also at the electron microscopic level, thereby suggesting the possibility of a direct chemical bonding between bone and titanium. It is concluded that the technique of osseointegration is a reliable type of cement-free bone anchorage for permanent prosthetic tissue substitutes. At present, this technique is being tried in clinical joint reconstruction. In order to achieve and to maintain such a direct contact between living bone and implant, threaded, unalloyed titanium screws of defined finish and geometry were inserted using a delicate surgical technique and were allowed to heal in situ, without loading, for a period of at least 3-4 months.     

掌指骨髓腔内骨整合式纯钛种植体的设计及界面生物力学研究

目的:自行开发设计掌指骨髓腔内骨整合式纯钛螺旋状种植体组件,通过动物实验对种植体-骨组织结合界面进行生物力学研究,为临床中种植体式手指赝复体修复指缺损提供依据。方法:根据成人正常掌骨和近节指骨及其髓腔的解剖学测量及特点,借鉴Branemark螺旋形牙种植体,研制开发临床用于掌指骨髓腔内植入的骨整合式纯钛螺旋状种植体。将此种种植体植入家兔胫骨髓腔内,术后分别于2、4、8、12、16周处死动物取材,进行大体观察和抗拉力测试。结果:制备出适合于成人掌指骨髓腔内植入的骨整合式纯钛螺旋型种植体组件及配件,种植体与骨可以形成良好的骨性结合,术后12周种植体-骨界面结合强度达到最大,与术后16周无明显差异。结论:该掌指骨髓腔内骨整合式纯钛螺旋状种植体组件自行开发设计,符合我国成人正常掌骨和近节指骨及其髓腔的解剖学特点,髓腔内植入后12周可与骨组织发生骨整合,达到最大结合强度。     

High dosage treatment of nitrogen-containing bisphosphonate ibandronate is required for osseointegration of cementless metal implants

Background There is evidence that application of a bisphosphonate can improve fixation of cementless metal implants by enhancing the extent of osseointegration, but the required dose regimen is still under discussion. The current preclinical study was designed to determine the optimal treatment dose of the nitrogen-containing bisphosphonate ibandronate to improve osseointegration of cementless metal implants. Methods The study was conducted in 52 female Sprague-Dawley rats in which uncoated and hydroxyapatite-coated titanium implants were surgically inserted into the medullary canal of each femur. The animals were randomly assigned to receive subcutaneous treatment with ibandronate 1 μg/kg body weight (osteoporosis dose) or 25 μg/kg (tumor dose) per day or saline solution for control. Results Histomorphometric evaluation revealed a significant enhanced extent of osseointegrated implant surface in the high-dose treatment group for both implants compared to the low-dose group and the control group. No significant differences were observed between the two implants in any group. Conclusions The results of the present study indicate that improved osseointegration of hydroxyapatite-coated and uncoated titanium implants is dose-dependent and requires high-dose application of bisphosphonate ibandronate equivalent to that needed to treat patients with tumor disease. Lower doses equivalent to those for treatment of osteoporosis showed no beneficial effect.     

The effect of platelet-rich plasma on bone healing around implants placed in bone defects treated with Bio-Oss: a pilot study in the dog tibia.

OBJECTIVE: The aim of this study was to examine the influence of platelet-rich plasma (PRP) used as an adjunct to Bio-Oss for the repair of bone defects adjacent to titanium dental implants. STUDY DESIGN: In 6 mongrel dogs, 12 screw-shaped titanium dental implants were inserted into the osteotomy sites in the dogs' tibias. Before implantation, a standardized gap (2.0 mm) was created between the implant surface and the surrounding bony walls. The gaps were filled with either Bio-Oss cancellous granules alone or Bio-Oss cancellous granules mixed with PRP. RESULTS: After 4 months, the Bio-Oss-treated defects revealed a significantly higher percentage of bone-implant contact than the defects treated with Bio-Oss and PRP (60.1% vs. 30.8%; P < .05). CONCLUSION: The results indicate that when PRP is used as an adjunct to Bio-Oss in the repair of bone defects adjacent to titanium dental implants, PRP may decrease periimplant bone healing.     

The fixation of the cemented femoral component. Effects of stem stiffness, cement thickness and roughness of the cement-bone surface

After cemented total hip arthroplasty (THA) there may be failure at either the cement-stem or the cement-bone interface. This results from the occurrence of abnormally high shear and compressive stresses within the cement and excessive relative micromovement. We therefore evaluated micromovement and stress at the cement-bone and cement-stem interfaces for a titanium and a chromium-cobalt stem. The behaviour of both implants was similar and no substantial differences were found in the size and distribution of micromovement on either interface with respect to the stiffness of the stem. Micromovement was minimal with a cement mantle 3 to 4 mm thick but then increased with greater thickness of the cement. Abnormally high micromovement occurred when the cement was thinner than 2 mm and the stem was made of titanium. The relative decrease in surface roughness augmented slipping but decreased debonding at the cement-bone interface. Shear stress at this site did not vary significantly for the different coefficients of cement-bone friction while compressive and hoop stresses within the cement increased slightly.     

Primary placement of osseointegrated implants in microvascular mandibular reconstruction

The goal of mandibular reconstruction is to rehabilitate the patient by restoring occlusal relationships, lower facial contour, oral continence, and a denture-bearing surface. One of the major advantages of the use of vascularized bone over all other methods of mandibular reconstruction is its ability to achieve dental rehabilitation rapidly. The use of osseointegrated dental implants is a valuable adjunct in oral rehabilitation. It provides the most rigid form of stabilization to withstand the forces of mastication. In situations in which soft tissue reconstruction or the height of the alveolar ridge is not sufficient for a tissue-borne denture, implants offer the most suitable alternative. Mandibular reconstruction with free tissue transfer techniques is ideally suited for the placement of implants. These can be inserted at the time of mandibular reconstruction. Four months after surgery, when the integration process has occurred, the implants are unroofed, loaded, and ready for prosthetic placement. We will present several representative patients who underwent mandibular reconstruction with microvascular free bone transfer who have been successfully rehabilitated by osseointegrated implants. The process of osseointegration, different types of dental implants, and issues regarding radiation and implants are discussed. This is the first report of dental rehabilitation by primary placement of dental implants in patients undergoing microvascular mandibular reconstruction.