A New Technique for Reconstruction of the Atrophied Narrow Alveolar Crest in the Maxilla Using Morselized Impacted Bone Allograft and Later Placement of Dental Implants

Use of Tisseel, a Fibrin Sealant, for Particulate Graft Stabilization

One clinical problem when augmenting a narrow or vertically deficient ridge is maintenance of the graft position during the immediate healing phase and preservation of the augmentation over time. The use of Tisseel (Baxter, Deerfield, IL), a fibrin sealant product, to stabilize particulate grafts, has been reported, and we have reviewed its use. Fibrinogen is converted to fibrin and forms a fibular network that binds the particulate graft. A protease inhibitor is included, which prevents lysis of the coagulum for at least 2 weeks and allows for fibrous ingrowth and graft stabilization. We have reviewed the reported data and included 2 case reports to demonstrate the use of Tisseel.

Fresh-frozen homologous bone in sinus lifting: histological and radiological analysis

BACKGROUND

The aim of this study was to evaluate radiological and histological characteristics of fresh-frozen homologous bone as grafting material for maxillary sinus floor augmentation. Radiological, histological and clinical evaluations were made.

METHODS

Twenty-three patients with a 2 mm to 6 mm alveolar ridge height in the posterior maxilla have been enrolled. Unilateral or bilateral sinus floor augmentations were performed with fresh frozen morcelized homologous bone. Together with implant placement, 7 months after surgery, a bone core was harvested for histological analysis. Radiological measurements were obtained by superimposition of CT scans carried out at the surgery time and six months later. A total of 93 implants were positioned.

RESULTS

A mean (±SD) increase in mineralized tissue height of 10.74±2.82 mm was noticed by comparing the CT scans. Histological analysis revealed the presence of newly formed bone in the grafted sites. The follow up period after the prosthetic load ranged from 8 to 31 months. One implant failure occurred.

CONCLUSIONS

Fresh frozen homologous bone seems to have a good healing pattern and to be a successful and steady grafting material for the treatment of maxillary ridge atrophy. It might be considered a valid alternative to autologous bone in sinus floor augmentation procedures.

Anterior atrophic mandible restoration using cancellous bone block allograft

BACKGROUND

Bone block grafting may be required to restore the alveolar process prior to implant placement in Kennedy Class IV partial edentulism of the anterior mandible.

PURPOSE

Evaluate the application of allograft cancellous bone blocks for the augmentation of the anterior atrophic mandible.

MATERIALS AND METHODS

Fourteen consecutive patients underwent augmentation with cancellous bone block allografts in the anterior mandible. A bony deficiency of at least 3 mm horizontally and up to 3 mm vertically according to computerized tomography para-axial reconstruction served as inclusion criteria. Following 6 months, 26 implants were placed and a cylindrical sample core was collected. All specimens were prepared for histological and histomorphometrical examination. The rehabilitation scheme was two dental implants, placed in the lateral incisor area, supporting a 4-unit implant-supported prosthesis.

RESULTS

Twenty-four blocks were placed in 14 patients. Mean follow-up was 26 ± 17 months. Mean bone gain was 5 ± 0.5 mm horizontally, and 2 ± 0.5 mm vertically. Twenty-six implants were used. Marginal bone loss at last follow up did not extend beyond the first thread. Block and implant survival rates were 91.6% and 100%, respectively. All patients but one received a fixed implant-supported prosthesis. Histomorphometrically, the mean fraction of the newly formed bone was 42%, that of the residual cancellous block-allograft 17%, and of the marrow and connective tissue 41%.

CONCLUSIONS

The potential of cancellous bone block allografts for reconstruction of Kennedy Class IV partial edentulism in the anterior mandible seems promising but still has to be evaluated scientifically in long-term observations.

Filling bone defects with β-TCP in maxillofacial surgery: A review

Reconstruction of bone defects prior to implant placement now involves synthetic substitutes such as β-TCP because of its ability to promote bone remodeling. Its capacity to be progressively substituted by the patient's bone allows to regenerate a dense bone volume. In addition, its availability in large quantities, avoiding the morbidity observed with harvesting autogenous bone, widens the operative indications. In this paper, the main indications of β-TCP in maxillofacial surgery (dentistry, parodontology and dental implant surgery) are reviewed. They include periodontal bone disease, bone disjunction, pre-implant surgery (sinus floor elevation and lateralization of the inferior alveolar nerve).

Histochemical and morphological aspects of fresh frozen bone: a preliminary study

Bone graft are used in dentistry for the reconstruction of severely atrophic jaws. Fresh frozen bone has no osteogenic property but it has osteoconductive and osteoinductive properties because its matrix contains growth factors such as vascular endothelial growth factor. The purpose of the present study was to evaluate morphological and protein expression characteristics of fresh frozen bone before graft and after six months of graft in patients who needed maxillary reconstruction. After 6 month of graft we observed the presence of viable bone as evidenced by full osteocyte lacunae and by the presence of RANKR, osteocalcin positive cells and vascular endothelial growth factor. In conclusion, our findings show that the fresh frozen bone after six month of graft is for the most part viable bone, encouraging its use as an alternative to autogenous bone for reconstructing maxillary bone defects prior to implant.

Block allograft for reconstruction of alveolar bone ridge in implantology: a systematic review

PURPOSE

The aim of this study was to evaluate the literature regarding clinical efficacy and predictability of block allograft for restoration of vertical and/or horizontal bone defects.

MATERIALS AND METHODS

A literature search was conducted in PubMed/MEDLINE and Cochrane databases about studies reporting the use of block allografts. The review included studies published in English from 1960 to 2011 and excluded single-case reports and articles that did not use block allograft stabilized by fixation screws.

RESULTS

The search revealed 567 articles, but only 14 were included, which were conducted in humans with a total of 194 patients treated with block allografts, totalizing 253 blocks.

CONCLUSIONS

Although a high success rate has been reported for the bone allograft survival, this systematic review demonstrated low level of scientific evidence articles with short follow-up time and diversified methodology with difficult possibilities to compare their results.

Allogeneic materials in complications associated with pre-implantation restoration of maxillary and mandibular alveolar processes. A four case report

There are numerous types of bone replacement materials used to regenerate atrophic alveolar processes before the elective intraosseous implantation. Properties of these materials differ one from another, therefore the choice of material should be thoroughly analysed as well as its type and texture in regard of intraoral conditions and the objective to be achieved. The study involved reconstruction of atrophic alveolar processes with allogeneic bone following unsuccessful use of synthetic and animal materials. The procedure of bone regeneration was performed with frozen bone block (case 1) and allogeneic bone granulate (cases 2, 3, 4) radiation-sterilised with 35 kGy prepared by the Tissue Bank. In all of the presented cases after 3-month implant reorganisation optimal width of the process was obtained, which allowed implant embedment (case 1) or correct implant submergence in the osseous tissue, when implantation took place at the same time (case 2, 3, 4). Allogeneic bone material both, in the form of a block as well as granulate, seems to be an adequate alternative for other materials used in order to widen the bone of the alveolar process, particularly in difficult, complicated cases, where the first regeneration procedure was not successful.

Marginal bone-level alterations at implants installed in block versus particulate onlay bone grafts mixed with platelet-rich plasma in atrophic maxilla. a prospective 5-year follow-up study of 15 patients

BACKGROUND

Extensive atrophy of the alveolar process may require a bone-grafting procedure prior to implant treatment. Autogenous bone grafts from the iliac crest, used as onlay block and particulate bone, have been used together with sinus-lift procedure in order to rehabilitate patients with extremely resorbed maxillae. However, there are to our knowledge no 5-year follow-up studies evaluating the extent of bone-level change in patients treated with respectively block and particulate autogenous bone grafts.

PURPOSE

The purpose of this prospective clinical study was to conduct a 5-year follow-up analysis with focus on bone-level alteration in block versus particulate onlay bone grafts.

MATERIAL AND METHODS

Fifteen out of originally 19 patients who were treated with iliac bone grafts and oral implants in the maxilla have been followed through the first 5 postoperative years. In a first study conducted on 19 patients, the role of platelet-rich plasma in conjunction with autogenous bone was evaluated. In this 5-year follow-up study, the marginal bone alterations have been documented at base line, 1 year and 5 years of loading to the nearest 0,1 mm at mesial and distal surfaces of the implants. Two implants were installed on each side of the midline in either block or particulate bone grafts giving test and control sides in each patient. Additionally, two implants on each side were installed in residual bone/grafted sinus floor.

RESULT

Marginal bone alteration in the anterior maxilla appeared larger at the side augmented by block bone at baseline, and after 1 and 5 years of loading, but the change was not statistically significant. Moreover, there was a significantly higher degree of marginal alteration during the first year of loading, compared with the examinations after 5 years.

CONCLUSION

The present follow-up study showed that there is no significant difference in the extension of resorption between block- and particulate autogenous bone grafts over a 5-year period. Most of the resorption occurred during the first year in function.

Iliac crest autogenous bone graft versus alloplastic graft and guided bone regeneration in the reconstruction of atrophic maxillae: a 5-year retrospective study on cost-effectiveness and clinical outcome

BACKGROUND

Reconstruction of the atrophic maxillae with autogenous bone graft and jawbone-anchored bridges is a well-proven technique. However, the morbidity associated with the concept should not be neglected. Furthermore, the costs for such treatment, including general anesthesia and hospital stay, are significant. Little data are found in the literature with regard to a cost-benefit approach to various treatment alternates.

PURPOSE

The aim of this retrospective study was to compare from a health-economical and clinical perspective the reconstruction of the atrophic maxillae prior to oral implant treatment either with autogenous bone grafts harvested from the iliac crest or the use of demineralized freeze-dried bone (DFDB) in combination with a thermoplastic carrier (Regeneration Technologies Inc., Alachua, FL, USA) and guided bone regeneration (GBR).

MATERIALS AND METHODS

A total of 26 patients (13 + 13) were selected and matched with regard to indication, sex, and age. The study was performed 5 years after the completion of the treatment. Implant survival, morbidity, and complications were analyzed. Furthermore, a detailed analysis of the total cost for the respective treatment modality was performed, including material, costs for staff, sick leave, etc.

RESULTS

The study revealed no statistical difference with regard to implant survival for the respective groups. The average total cost, per patient, for the DFDB group was 22.5% of the total cost for a patient treated with autogenous bone grafting procedures.

CONCLUSIONS

The study concluded that reconstruction of atrophic maxillae with a bone substitute material (DFDB) in combination with GBR can be performed with an equal treatment outcome and with less resources and a significant reduced cost in selected cases compared with autogenous bone grafts from the iliac crest.

The relevance of Choukroun's platelet-rich fibrin and metronidazole during complex maxillary rehabilitations using bone allograft. Part II: implant surgery, prosthodontics, and survival

Extensive bone grafting remains a delicate procedure, due to the slow and difficult integration of the grafted material into the physiological architecture. The recent use of platelet concentrates aims to improve this process of integration by accelerating bone and mucosal healing. Choukroun's platelet-rich fibrin (PRF) is a healing biomaterial that concentrates in a single autologous fibrin membrane, most platelets, leukocytes, and cytokines from a 10-mL blood harvest, without artificial biochemical modification (no anticoagulant, no bovine thrombin). In this second part, we describe the implant and prosthetic phases of a complex maxillary rehabilitation, after preimplant bone grafting using allograft, Choukroun's PRF membranes, and metronidazole. Twenty patients were treated using this new technique and followed up during 2.1 years (1-5 years). Finally, 184 dental implants were placed, including 54 classical screw implants (3I, Palm Beach Gardens, FL) and 130 implants with microthreaded collar (46 from AstraTech, Mölndal, Sweden; 84 from Intra-Lock, Boca Raton, FL). No implant or graft was lost in this case series, confirming the validity of this reconstructive protocol. However, the number of implants used per maxillary rehabilitation was always higher with simple screw implants than with microthreaded implants, the latter presenting a stronger initial implant stability. Finally, during complex implant rehabilitations, PRF membranes are particularly helpful for periosteum healing and maturation. The thick peri-implant gingiva is related to several healing phases on a PRF membrane layer and could explain the low marginal bone loss observed in this series. Microthreaded collar and platform-switching concept even improved this result. Multiple healing on PRF membranes seems a new opportunity to improve the final esthetic result.

The relevance of Choukroun's platelet-rich fibrin and metronidazole during complex maxillary rehabilitations using bone allograft. Part I: a new grafting protocol

Extensive bone grafting remains a delicate procedure, because of the slow and difficult integration of the grafted material into the physiological architecture. The recent use of platelet concentrates aims to improve this process of integration by accelerating bone and mucosal healing. Choukroun's platelet-rich fibrin (PRF) is a healing biomaterial that concentrates in a single autologous fibrin membrane, most platelets, leukocytes, and cytokines from a 10 mL blood harvest, without artificial biochemical modification (no anticoagulant, no bovine thrombin). Whether used as a membrane or as fragments, PRF allows a significant postoperative protection of the surgical site and seems to accelerate the integration and remodeling of the grafted biomaterial. These properties are particularly helpful for vestibular bone grafting on the alveolar ridges. Moreover, it provides a very high quality of gingival maturation.A small quantity of a 0.5% metronidazole solution (10 mg) can also be used to provide an efficient protection of the bone graft against unavoidable anaerobic bacterial contamination. This article describes a new technique of total maxillary preimplant bone grafting using allograft, Choukroun's PRF membranes and metronidazole. This first part focused on the preimplant reconstructive treatment using allogeneic bone granules. PRF membranes are particularly helpful to protect the surgical site and foster soft tissue healing. This fibrin biomaterial represents a new opportunity to improve both the maturation of bone grafts and the final esthetic result of the peri-implant soft tissue.