Autogenous Block Grafts Research Articles

Reconstruction of large soft tissue chin defects with a combination of z-plasty and inferior submental advancement flaps

Autogenous block grafting has long been a modality of treatment to create adequate bone volume in larger osseous deficient ridges prior to dental implant placement. With some autogenous donor sites being unfavorable anatomically to harvest from, clinicians have turned to using allogenic block materials. With the development of allogenic corticocancellous J blocks, it has allowed the clinician to seek other options of grafting when our gold standard, autogenous blocking, is unavailable.

Role of Cone Beam Computed Tomography in Rehabilitation of a Traumatised Deficient Maxillary Alveolar Ridge Using Symphyseal Block Graft Placement

Deficiencies in the alveolar ridges cause multiple problems in achieving aesthetic and functional outcome of implant therapy and are commonly restored by using onlay graft from intraoral source. Careful assessment of the recipient as well as the donor site using cone beam computed tomography (CBCT) is a prerequisite to ideal treatment planning. This paper highlights the critical role of CBCT in planning a successful rehabilitation of traumatised deficient anterior maxillary alveolar ridge using autogenous block graft from mandibular symphysis, followed by implant placement. A 21-year-old male reported with missing right maxillary lateral incisor due to traumatic avulsion 6 months back. A concavity was found on the labial aspect of edentulous area. Serial transplanar images on CBCT revealed gross irregular radiolucency in place of labial cortical plate. Using CBCT, size of the required block was estimated, and mandibular symphyseal area was evaluated for the feasibility of harvesting a graft of suitable dimension. Onlay block graft was harvested from mandibular symphysis and placed at the edentulous site to augment the alveolar ridge. Implants were placed 5 months later and loaded successfully after osseointegration. After 1 year of followup, implant-based prosthesis is working well, without any complications.

Effects of low-intensity pulsed ultrasound on autogenous bone graft healing

Pulsed ultrasonic waves have been shown to accelerate bone healing. The aim of this study was to evaluate the effects of low-intensity pulsed ultrasound on bone healing. Thirty-two femurs from 16 skeletally mature male Wistar albino rats were used. Two defects were produced in each femur with a 3-mm-diameter trephine bur and then autogenous cortical grafts were placed in 1 defect. The animals in the experiment group received a daily 20-minute ultrasound treatment for 15 days. All animals were killed on the 18th postoperative day. Dual-energy x-ray absorptiometry values and biochemical markers in the experimental side were significantly higher than those in the control side at the early period of bone healing. Low-intensity pulsed ultrasound treatment accelerates bone healing both in bone defects and in bone defects filled with cortical autogenous block graft.

Immunolocalization of bone morphogenetic protein 2 during the early healing events after guided bone regeneration

The objective of this study was to evaluate the immunolocalization of bone morphogenetic protein 2 (BMP-2) after autogenous block grafting covered or not with an e-PTFE membrane. Forty-eight rats were divided into 2 groups, autogenous block graft (B) and autogenous block graft + e-PTFE membrane (MB), and were evaluated by immunohistochemistry at baseline and 3, 7, 14, 21, and 45 days. The largest number of positive cells in the recipient bed was observed after 3 days in both groups. At the graft border, the largest number of positive cells was seen after 7 days in group B and after 14 days in group MB. The highest proportion of staining in the graft was observed after 3 days in group B and after 21 days in group MB. High proportions of stain were related to intense revascularization and osteogenesis. Except for the interface, BMP-2 staining occurred later in group MB than in group B in all structures analyzed.

Lateral ridge augmentation using a PCL‐TCP scaffold in a clinically relevant but challenging micropig model

In implant dentistry, there is a need for synthetic bone substitute blocks to support ridge augmentation in situations where large bone volumes are missing. Polycaprolactone-based scaffolds demonstrated excellent results in bone tissue engineering applications. The use of customized polycaprolactone-tricalcium phosphate (PCL-TCP) displayed promising results from recent rat femur and rabbit calvaria studies. However, data from clinically representative models in larger animals do not exist. To evaluate new bone formation in association with a novel PCL-TCP scaffold in comparison with an autogenous bone block graft for the reconstruction of large dentoalveolar defects in a clinically relevant but challenging pig jaw model. Chronic, non-contained one-wall defects were created in the mandible of micropigs and randomly assigned to receive one of the following guided bone regeneration (GBR) procedures for a period of 6 months. (A) Collagen membrane + autogenous block graft or (B) Collagen membrane + PCL-TCP scaffold. Micro computed tomography (μ-CT), histology and histomorphometry were used to assess new bone formation. Although μ-CT and histomorphometric analysis demonstrated a slight discrepancy between the measurements, the group utilizing autogenous bone grafts consistently reported superior new bone formation as compared to PCL-TCP scaffolds. When measured using μ-CT, the ratio of bone volume fraction for PCL-TCP scaffolds with respect to autografts yielded a mean efficacy of approximately 51%. Histological examination revealed that under favorable conditions, the new bone matrix and new bone marrow were in direct contact with the PCL-TCP scaffold rods and invading the interstices, suggesting good biocompatibility and high osteoconductivity. Autograft block grafts demonstrated 48.5-57.4% of pronounced resorption after 6 months following ridge augmentation. PCL-TCP scaffolds have demonstrated the potential application for lateral ridge augmentation following a healing period of 6 months in a micropig model.

Use of resorbable screws for autogenous onlay block graft fixation: a histological analysis in rabbits

Use of resorbable screws for autogenous onlay block graft fixation: a histological analysis in rabbits

Island Osteoperiosteal Flaps With Interpositional Bone Grafting in Rabbit Tibia: Preliminary Study for Development of New Bone Augmentation Technique

Loss of alveolar vertical height is one of the most challenging conditions in the field of implantology. A few augmentation techniques have been proposed to address this challenge, including guided bone regeneration, alveolar distraction osteogenesis, sandwich osteotomies and autogenous block grafting. This is a pre-clinical study of lengthening the alveolar bone height using a thin osteoperiosteal bone flap, the "island bone flap" or i-flap, to establish vitality, stability and incorporation of the augmentation material after healing. A rabbit tibia model was designed for this study and included 8 rabbits. An osteoperiosteal osteotomy was performed through the periosteum cutting 1 mm of the outer cortex of the bone in order to elevate a bone flap. The bone flap was detached, and remained attached to the periosteum as a free floating osteoperiosteal flap, and the resultant defect was filled with xenograft. The histological analysis demonstrates formation of maturing trabeculae in the site of the i-flap. In cases of trauma to the bone marrow during the surgical procedure, a centripetal gradient of bone remodeling from the surgical site toward the periphery was evident, while the bony component of the i-flap maintained vital. Creating a free floating osteoperiosteal flap, used here with interpositional grafting in a rabbit tibia, appears to heal by both appositional modeling and creeping substitution remodeling. Volumetric augmentation persisted despite exuberant bone turnover in this animal model. This technique holds promise as a possible augmentation bone grafting approach for use in alveolar reconstruction.

Use of Titanium Mesh in Lieu of a Fixation Screw to Stabilize an Autogenous Block Graft: A Case Report

Localized alveolar augmentation is carried out either before, during, or sometimes after implant placement. The placement of autogenous graft as a block or a particulate alone or in combination with an organic bone mineral has been practiced with a great deal of success. The block graft is secured in place with a screw and protected by a membrane. This case report describes the treatment of a female patient with a bucco-lingual bone deficiency grafted with autogenous block and a titanium mesh. Five months later, implant was placed in the grafted area. The definitive prosthesis was cemented 6 months later and followed up for 2 years.

Guided bone regeneration with autogenous block grafts applied to Le Fort I osteotomy for treatment of severely resorbed maxillae: a 4‐ to 6‐year prospective study

Edentulism causes progressive bone resorption of the maxillae, which can lead to altered maxillo-mandibular relationships. The aim of the study was to evaluate the applicability of guided bone regeneration (GBR) to Le Fort I osteotomies with interpositional bone grafts for treatment of patients with severe maxillary atrophy. Twenty consecutive patients characterized by severely atrophic maxillae were treated from January 2003 to January 2006 in order to resolve maxillary edentulism. All patients underwent pre-prosthetic surgery, including a Le Fort I osteotomy associated with autologous interpositional bone grafts to move the alveolar arch forward and to resolve the maxillary atrophy. Barrier membranes were also used to cover the bone grafts and the osteotomy line, favoring the healing process according to GBR principles. Maxilla advancement and alveolar crest augmentation were measured to assess the degree of reconstruction. A total of 154 implants were inserted in reconstructed maxillae 4 months after surgery and were restored with fixed full-arch dentures after another 4 months. Surgical and prosthetic complications were recorded and previously established implant success criteria were used to assess the success of this treatment protocol. The outcome of pre-prosthetic surgery and implant-supported rehabilitation was prospectively evaluated every year. All Le Fort I osteotomies were successfully carried out, with a mean maxilla advancement of 4.2 cm (range: 3.1-5 cm), which appeared to be stable during the follow-up. After a mean follow-up of 66.4 ± 18.4 months, only four implants failed according to the success criteria, yielding a cumulative success rate of 95.8%. Le Fort I osteotomies with the use of barrier membranes to cover the interpositional bone grafts can be a predictable treatment for edentulous patients with severely resorbed maxillae. The study data suggest that this approach makes it possible to compensate for both sagittal and vertical discrepancies due to maxilla atrophy, with a minimum resorption of advanced maxillae and grafted bone. A GBR-based protocol seems to lead to high implant success rates, although further randomized controlled studies are needed to demonstrate the usefulness and advantageousness of GBR.

Restoration of Maxillary Anterior Defect using Autogenous Block Graft and Optimizing the Esthetics using Zirconia Restoration

The placement of dental implants in the anterior maxilla is a challenge for clinicians because of patients’ exacting esthetic demands and difficult pre-existing anatomy. An atrophic alveolar ridge frequently causes functional, esthetic and prosthodontic problems. New approaches to implant therapy are available for patients with insufficient bone volume, like bone grafts, which may be autografts, xenografts, allografts or alloplasts. In maxillofacial reconstruction, the autogenous bone graft is still the “gold standard” for bone augmentation procedures. All ceramic crown emerging from a healthy peri-implant mucosa would fulfil the ultimate goal of a life-like restoration. This article describes a method for harvesting intramembranous monocortical bone from the symphysial region for horizontal alveolar ridge augmentation followed by implant placement in the anterior maxilla. This method provided enough bone volume for insertion of an implant in an optimal position with total bony coverage and esthetics.

Reconstruction of Posterior Mandibular Alveolar Ridge Deficiencies With the Piezoelectric Hinge–Assisted Ridge Split Technique: A Retrospective Observational Report

Reconstruction of alveolar defects in the posterior edentulous mandible can be a difficult task. In addition to complicating anatomic features, such as the inferior alveolar nerve, mental foramen, oblique ridge, and lingual undercut of the mylohyoid ridge, edentulous ridges in the posterior mandible have thicker cortices and decreased volumes of vascular trabecular bone than their maxillary counterparts. Traditionally, these areas have been treated with autogenous block grafts. Significant resorption of these grafts, in combination with patient morbidity at secondary donor sites, has led clinicians to seek alternatives for augmenting the edentulous posterior mandible. The aim of this retrospective consecutive case series is to report on both the technique of the piezoelectric hinge-assisted ridge split procedure for augmenting these sites and the results that were achieved. Thirteen patients with 17 horizontal alveolar ridge deficiencies of the posterior mandible were treated with the piezoelectric hinge-assisted ridge split procedure. After an average healing period of 14 weeks, dental implants were placed into the augmented sites. Intrasurgical alveolar ridge measurements taken at the initial surgery and subsequently at the time of implant placement documented the horizontal gains achieved by this procedure. Overall mean gain in horizontal width was 4.03 mm (± 0.67). For single implant-site augmentations, the mean gain was 3.38 mm (± 0.25). For multiple adjacent implant-site augmentations, mean gain was 4.25 mm (± 0.62). A total of 31 dental implants were successfully placed in all sites and none required additional augmentation procedures. There were no instances of adverse outcomes, such as neurosensory deficits or sequestration of mobilized buccal plates. After a minimum of 6 months of loading, all dental implants have been successful. This retrospective observational report demonstrates that the piezoelectric hinge-assisted ridge split procedure can achieve substantial gains in horizontal ridge width of the edentulous posterior mandible without associated morbidity. Further prospective and larger observational studies are warranted to see if this is true over a larger patient population and to compare this technique to other more traditionally used approaches.

Clinical Evaluation of Freeze-Dried Cancellous Block Allografts for Ridge Augmentation and Implant Placement in the Maxilla

A number of grafting materials have been used in vertical and horizontal ridge augmentation to enable implant placement in optimal positions. Autogenous block grafts from intraoral or extraoral sites have been used with positive results. Allograft blocks with cortical bone are also used for ridge augmentation. In this case series, cancellous allograft blocks were used for horizontal augmentation of the maxilla. The observed increase in ridge width allowed subsequent implant placement after a 5-month healing period. Four months after placement, the implants were uncovered and restored. The results suggest that cancellous block allografts may be a viable alternative to autogenous block grafts or cortical allograft blocks in treatment of deficient maxillary alveolar ridges to allow subsequent implant placement in optimal position in the maxilla.

Maxillary Tuberosity Block Bone Graft: Innovative Technique and Case Report

Hard tissue defects resulting from trauma, infection, or tooth loss often lead to an unfavorable anatomy of maxillary and mandibular alveolar processes that become not suitable for implant therapy without bone grafting. The goal of pre-implant bone augmentation of the deficient alveolar ridge is reconstruction of the proper alveolar anatomy through the techniques of socket preservation, horizontal and vertical ridge augmentation, sinus bone grafting, and others. A variety of bone grafts and bone grafting materials have been used in the last 30 years for augmentation of deficient alveolar ridge for the purpose of implant treatment of partially and completely edentulous patients. Bone grafting options include autogenous, allogeneic, xenogeneic, synthetic bone, and combination of above. Autogenous bone grafts are considered "the gold standard" due to their compatibility and osteogenic potentials to form the new bone by processes of osteogenesis, osteoinduction, and osteoconduction. A particulate and block autogenous bone has been used for correction of alveolar ridge deficiency. Extraoral sites of autogenous block grafts include: ilium, calvarium, tibia, rib, and others. Intraoral sites of autogenous block grafts include symphysis and retromolar-ramus areas. In the clinical practice, a maxillary tuberosity bone graft has often been used as a particulate graft for augmentation of deficient alveolar ridge or maxillary sinus prior to or simultaneously with implant insertion. This article presents an innovative technique and reports a case of the maxillary tuberosity block bone graft that can be used to correct moderate to severe localized defects of the alveolar process prior to implant placement.

Poster 033: Screw “Tent-Pole” Grafting Technique for Vertical Augmentation of the Severely Atrophic Alveolar Ridge for Implant Site Preparation

Objectives: Horizontal alveolar ridge augmentation using intra-oral autogenous block grafts to augment localize alveolar ridge defects prior to implant placement is a predictable method. However, reconstruction of large vertical alveolar defects has traditionally been difficult. The purpose of this study is to evaluate the effectiveness of using titanium screws in combination with particulate human mineralized allograft, in a “tenting” fashion, to augment large vertical alveolar ridge defects for implant placement.

Harvesting of intraoral autogenous block grafts from the chin and ramus region: Preliminary results with a variable square pulse Er:YAG laser

It was the aim of this pilot study to evaluate the feasibility, benefits and limitations of a variable square pulse (VSP) Er:YAG laser for harvesting intraoral bone grafts from either the chin or ramus region. In 12 patients (5 female, 7 male) a VSP Er:YAG laser was used to harvest bone grafts either from the ramus (3) or the symphyseal area (9). For the osteotomies, the Er:YAG laser was applied with a pulse energy of 1,000 mJ, a pulse duration of 300 microseconds, and a frequency of 12 Hz (energy density 157 J/cm(2)). The spot size was 0.9 mm and the handpiece was kept at a distance of about 10 mm from the bone surface. There was no visible carbonization or osseous debris on the surface of the osteotomy gap. Damage of adjacent soft tissue structures by mechanical or thermal trauma was minimal. Cutting efficiency was excellent and the overall time required for the procedure was not increased. However, due to a free manual positioning of the laser beam in the non-contact mode, it was difficult to get a well defined osteotomy line without irregularities on the surface. Slight deviations of the original angulation of the laser beam led to considerable bone loss which restricted osteotomy of ramus grafts to three cases. Depth control was limited to visual inspection. The bone ablation technique using a (VSP) Er:YAG laser yielded superior clinical results without impairment of wound healing and in comparison to other laser systems, no significant time loss occurred. Yet, the missing depth control and the necessity of carefully handling the laser beam position and its angulation limit the use of a (VSP) Er:YAG laser to regions where a safe and fixed guidance of the laser beam is feasible.

Clinical Evaluation of a Cancellous Block Allograft for Ridge Augmentation and Implant Placement: A Case Report

A number of grafting materials have been used in vertical and horizontal ridge augmentation to enable implant placement in optimal positions. Autogenous block grafts from intraoral or extraoral sites have been used with positive results. Allograft blocks with cortical bone are also used for ridge augmentation. In this case report, a cancellous allograft block was used for horizontal augmentation of the maxilla. The observed increase in ridge width allowed subsequent implant placement after a 5 month healing period. After 4 months the implant was uncovered and restored as a unit in a 4-unit fixed splinted implant reconstruction. The result suggests that cancellous block allografts may be a promising alternative to autogenous block grafts or cortical allograft blocks in treatment of deficient maxillary alveolar ridges to allow subsequent implant placement in optimal position.

Cortical Tenting Grafting Technique in the Severely Atrophic Alveolar Ridge for Implant Site Preparation

Alveolar ridge augmentation using intraoral autogenous block grafts to augment localized alveolar ridge defects before implant placement is a predictable method. However, large severely atrophic edentulous segments may require extraoral donor sites. The purpose of this study was to evaluate the effectiveness of using intraoral cortical block grafts in combination with particulate human mineralized allograft, in a "tenting" fashion, to augment large atrophic alveolar ridge defects for implant placement. This prospective case study evaluated augmentation in 10 consecutive patients with severely resorbed alveolar ridges missing a minimum of 4 adjacent teeth. Before augmentation, all grafted sites were deemed inadequate for placement of a standard 4-mm-diameter implant. Horizontal ridge augmentation was performed using autologous membranous cortical bone grafts from an oral donor site to tent out the soft tissue matrix and periosteum for the adjacent particulate allograft. The ridges were clinically evaluated 4 to 5 months after augmentation, and 42 implants were placed at that time. Implants were successfully placed at all grafted sites 4 to 5 months after the original graft date. Clinical evaluation of the grafted sites upon re-entry revealed uniform ridge anatomy. All edentulous segments had at least 2 implants placed of at least 4.0 mm diameter. In all, 42 implants were placed into grafted sites in the 10 patients. Implants were checked for osseointegration by using a counter torque of 35 N.cm. One implant failed to integrate. Mean follow-up was 22 months after implant placement. All augmented ridges had retained their functional and esthetic integrity at 1 year after original augmentation. Tenting of the periosteum and soft tissue matrix using a cortical bone block maintains space and minimizes resorption of the particulate allograft volume. In addition, bridging the cortical blocks with particulate bone avoids unaesthetic ridge defects between cortical block grafts in larger ridge defects. The result was a more uniform and esthetic alveolar ridge, capable of maintaining an implant-supported prosthesis. The technique offers predictable functional and esthetic reconstruction of large-volume defects without extensive amounts of autogenous bone. This offers a superior functional and esthetic result than with either cortical or particulate grafting alone.

Ultraschallbasiertes Knochenschneiden in der Oralchirurgie: eine Übersicht anhand von 60 Patientenfällen

Surgical reconstruction of bony defects in the oral cavity can often be challenging since thin and fragile bony structures are especially prone to fracture cased by bulky cutting tips or the application of significant pressure by conventional mechanical instruments. The risk of accidental damage to adjacent soft tissue structures, such as nerves, by a dental drill or saw is also extremely high. The use of modulated ultrasound (piezosurgery) makes it possible to overcome such complications as a result of the precise and minimally invasive surgery technique which is limited to mineralized hard tissue. In 60 patients (38 male, 22 female) a piezosurgery device was used for different bone augmentation procedures before dental implant placement. The instrument uses modulated ultrasound (25 - 30 kHz) and the amplitude of the working tip ranges from 60 mum to 200 mum. The device was employed for sinus floor elevation (25), alveolar ridge augmentation using an autogenous block graft (25), alveolar ridge splitting (5) or lateralization of the alveolar nerve (5). Physiological sodium chloride was used as a cooling solution. For all osteotomies mode boosted burst c and pump 5 were used. Piezoelectric osteotomy permitted micrometric selective cutting and a clear surgical site due to the cavitation effect created by the cooling solution and the oscillating tip. No excessive bleeding was encountered. The risk of accidental soft tissue harm, such as perforating the sinus membrane or damaging adjacent nerves, was definitely lower than in the case of a conventional bur. No serious complications were encountered in the postoperative wound healing process after 2, 14, 30 and 90 days. However, the surgical procedures were time-consuming. Piezosurgery is an advantageous osteotomy technique for delicate structures in the oral and maxillofacial region. With respect to osteotomies of thin and fragile bones, the application of ultrasound is superior to other mechanical instruments because of the extremely precise and virtually arbitrary cut geometries, easy handling, efficient bone ablation and minimal accidental damage to adjacent soft tissue structures.

Horizontal ridge augmentation using autogenous block grafts and the guided bone regeneration technique with collagen membranes: a clinical study with 42 patients

To analyze the clinical outcome of horizontal ridge augmentation using autogenous block grafts covered with an organic bovine bone mineral (ABBM) and a bioabsorbable collagen membrane. In 42 patients with severe horizontal bone atrophy, a staged approach was chosen for implant placement following horizontal ridge augmentation. A block graft was harvested from the symphysis or retromolar area, and secured to the recipient site with fixation screws. The width of the ridge was measured before and after horizontal ridge augmentation. The block graft was subsequently covered with ABBM and a collagen membrane. Following a tension-free primary wound closure and a mean healing period of 5.8 months, the sites were re-entered, and the crest width was re-assessed prior to implant placement. Fifty-eight sites were augmented, including 41 sites located in the anterior maxilla. The mean initial crest width measured 3.06 mm. At re-entry, the mean width of the ridge was 7.66 mm, with a calculated mean gain of horizontal bone thickness of 4.6 mm (range 2-7 mm). Only minor surface resorption of 0.36 mm was observed from augmentation to re-entry. The presented technique of ridge augmentation using autogenous block grafts with ABBM filler and collagen membrane coverage demonstrated successful horizontal ridge augmentation with high predictability. The surgical method has been further simplified by using a resorbable membrane. The hydrophilic membrane was easy to apply, and did not cause wound infection in the rare instance of membrane exposure.

Current concepts in periodontal bioengineering

Repair of tooth supporting alveolar bone defects caused by periodontal and peri-implant tissue destruction is a major goal of reconstructive therapy. Oral and craniofacial tissue engineering has been achieved with limited success by the utilization of a variety of approaches such as cell-occlusive barrier membranes, bone substitutes and autogenous block grafting techniques. Signaling molecules such as growth factors have been used to restore lost tooth support because of damage by periodontal disease or trauma. This paper will review emerging periodontal therapies in the areas of materials science, growth factor biology and cell/gene therapy. Several different polymer delivery systems that aid in the targeting of proteins, genes and cells to periodontal and peri-implant defects will be highlighted. Results from preclinical and clinical trials will be reviewed using the topical application of bone morphogenetic proteins (BMP-2 and BMP-7) and platelet-derived growth factor-BB (PDGF) for periodontal and peri-implant regeneration. The paper concludes with recent research on the use of ex vivo and in vivo gene delivery strategies via gene therapy vectors encoding growth promoting and inhibiting molecules (PDGF, BMP, noggin and others) to regenerate periodontal structures including bone, periodontal ligament and cementum.