Corticocancellous fresh-frozen allograft bone blocks for augmenting atrophied posterior mandibles in humans.

Rafael R. Dias Felipe P. Sehn Thiago de Santana Santos Erick R. Silva Gavriel Chaushu Samuel P. Xavier

Authors’ affiliations: Rafael R. Dias, Felipe P. Sehn, Thiago de Santana Santos, Erick R. Silva, Samuel P. Xavier, Department of Oral and Maxillofacial Surgery and Periodontology, Ribeir~ ao Preto Dental School, University of S~ ao Paulo, S~ ao Paulo, Brazil Gavriel Chaushu, Department of Oral and Maxillofacial Surgery, School of Dentistry, Tel Aviv University, Tel Aviv, Israel Gavriel Chaushu, Department of Oral and Maxillofacial Surgery, Rabin Medical Center, Petah Tikva,Israel Corresponding author: Samuel P. Xavier Department of Oral and Maxillofacial Surgery and Periodontology Ribeir~ao Preto Dental School, University of S~ao Paulo Avenida do Caf e, S/N 14040-904 Ribeir~ao Preto-SP, Brazil Tel.: +55 16 36023980 Fax: +55 16 36024788 e-mail: [email protected]

Corticocancellous fresh-frozen allograft bone blocks for augmenting atrophied posterior mandibles in humans

Key words: atrophic mandible, fresh-frozen bone allograft, histological analysis, histomorph-

ometry, implants, volumetric Abstract Background: Allograft fresh-frozen bone (FFB) is an alternative to autogenous bone for oral implantation due to bone quantity availability and lower morbidity for patients. Few specific studies about the use of FFB for reconstructing the posterior mandibular alveolar crest have been conducted. Objective: The objective of this study was to evaluate histological, histomorphometrical, and volumetric aspects of FFB allografts used to augment atrophied posterior mandible bone ridges. Materials and methods: Sixteen hemi-mandibles of twelve patients presenting with critical alveolar atrophy were three-dimensionally reconstructed using corticocancellous FFB. Thirty blocks were fixed with titanium screws and covered with particulate bovine bone mineral and collagen membrane. Volumetric data were obtained by cone beam computed tomography analysis after 6 months, implants were inserted, and bone biopsies were harvested and sent for histological and histomorphometric analyses. Results: The blocks were distributed between nine female and three male patients (mean age, 50.9 8.3 years). Thirty implants were installed, and the implant survival rate was 96.66%. Histology demonstrated newly formed vital bone contacting residual acellular allograft bone and connective tissue. The histomorphometric analysis showed 18.9 8.1% newly formed bone and 32.5 14.8% allograft residual bone. Graft absorption was 45% for height and volume, and both measures were significantly different (P < 0.001). Conclusion: Fresh-frozen allografts are a viable alternative for reconstructing an atrophied mandible in the posterior region, allowing for new bone formation, installation of implants, and prosthetic loading.

Date: Accepted 16 September 2014 To cite this article: Dias RR, Sehn FP, de Santana Santos T, Silva ER, Chaushu G, Xavier SP. Corticocancellous fresh-frozen allograft bone blocks for augmenting atrophied posterior mandibles in humans. Clin. Oral Impl. Res. 27, 2016, 39–46 doi: 10.1111/clr.12509

Bone atrophy of the posterior mandible residual alveolar ridge presenting height and/or thickness limitations is a challenge for dental implant installation. Use of an appositional autograft (Penarrocha-Oltra et al. 2014), interpositional autograft (Bormann et al. 2010), distraction osteogenesis (Zwetyenga et al. 2012), guided bone regeneration with membranes (Simion et al. 2007a,b; Parrish et al. 2009), lateralization or nerve transposition of the inferior alveolar bundle (Metzger et al. 2006; Khajehahmadi et al. 2013), and short implants (Kim et al. 2013; Mezzomo et al. 2014) are the most commonly used techniques for implantsupported rehabilitation in these areas. An autogenous bone graft has advantages and is considered the gold standard (Sajid

© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

et al. 2011) for its properties of osteoconduction, osteoinduction, and osteogenic potential (Hoexter 2002; Marx 2007), as well as providing a satisfactory three-dimensional (3D) framework (Petrungaro & Amar 2005). However, morbidity of the donor site (Khan et al. 2005; Nkenke & Neukam 2014), longer surgical time, and higher cost are disadvantages (Ellis & Sinn 1993; Sohn et al. 2009). Potential graft reabsorption of up to 87% has been observed in some studies. Nevertheless, techniques are available to decrease this problem, such as adding bovine bone mineral (BBM) to the graft surfaces (Maiorana et al. 2005, 2011) and perforating the native bone bed to possibly improve graft incorporation (Pedrosa et al. 2009), as well as the use of guided bone

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Dias et al Fresh-frozen allograft in posterior mandible

regeneration principles (Buser et al. 1999). Thus, there is demand for bone substitutes to overcome these disadvantages. Several types of grafts such as synthetic biomaterials, allografts, xenografts, and autografts have been tested and used to repair bone defects (Damien & Parsons 1991). Synthetic biomaterials are suitable alternatives to avoid the risks associated with autografts and allografts. However, these manufactured biomaterials do not display osteogenic properties and act only as scaffolds for bone formation (Stockmann et al. 2012). Allograft bone has disadvantages such as risk of host reactions due to genetic differences, disease transmission, and ethical and religious issues (Damien & Parsons 1991). Despite these problems, the use of fresh-frozen allografts in oral implantology is increasing due to easy acquisition from tissue banks, unlimited bone quantity, easy handling, reduced surgical and anesthesia time, cost (Hardin 1994; Dahlin & Johansson 2011), minor bleeding (Gamradt & Lieberman 2003), decreased postoperative morbidity due to absence of a donor area (Barone et al. 2009), and improved safety techniques (Macedo et al. 2012). Recent studies have shown that a freezedried bone allograft (FDBA) is a viable alternative for reconstructing atrophied posterior mandible bone (Nissan et al. 2011a,b). However, few studies have assessed the use of fresh-frozen bone (FFB) blocks in the posterior mandible (Macedo et al. 2012; Pimentel et al. 2014). This study evaluated the clinical, histological, histomorphometric, and volumetric behavior of corticomedullary grafts in FFB blocks, using bone augmentation techniques and maintenance of graft volume in atrophied posterior human mandibles.

was a bone deficiency limiting dental implant rehabilitation in the posterior mandible with ≤6 mm bone remaining from the alveolar inferior bundle (impossible to correctly rehabilitate using short implants). Moreover, bone quality was not compromised by use of radiotherapy or bisphosphonates. Patients had correct alignment with occlusion and leveling of teeth at the bone (patients without this occlusal condition were treated by an orthodontist). Exclusion criterion was no compromised general health (ASA III or IV). All procedures were fully explained to the patients who signed informed consent, and this study protocol was approved by the Ethical Committee for Human Studies (Committee CAAE: 01473512.4.0000.5419) at the School of Dentistry of the Ribeir~ao Preto of the University of S~ao Paulo, S~ao Paulo, Brazil. Corticocancellous allograft bone blocks from a musculoskeletal tissue bank (UNIOSS, Marilia, Brazil) were obtained from the

(a)

distal femoral epiphysis with approximate dimensions of 20 9 10 9 6 mm. The allograft blocks were characterized by a 1–2 mm cortical outer layer width and 4–5 mm of cancellous bone containing trabecular spaces (Figs 1 and 2). The backward planning approach included an evaluation of dental occlusion through an articulator analysis to better assess the number, position, and size of prosthetic crowns. Cone beam computed tomography (CBCT) was performed to identify the height and width of residual bone, distance from the alveolar bundle, amount of graft required, and the proper site for implant placement. All surgeries were performed by the same experienced surgeon. Surgical procedure

Prophylactic amoxicillin (1 g) was prescribed preoperatively in all cases. Under local anesthesia (2% mepivacaine with 1 : 100.000 epinephrine), the alveolar ridge was exposed to allow visualization of the defect (Fig. 3). A full

(b)

Fig. 1. Allogenic bone block modeled on an inverted “L” (C, cortical; M, medullary).

(a)

(b)

Hypothesis

We hypothesized a novel use of FFB for bone vertical deficiency repair of the posterior mandible (H1) or not (H0). Furthermore, we only used BBM to cover the bone allograft (H2) to reduce superficial absorption after implant placement and to improve the success rate of dental implantation.

Material and methods As inclusion criteria, all patients were ≥18 years old, male or female, had good general physical and mental health, nonsmokers, and had good oral health with no active periodontitis. The alveolar defect morphology

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Clin. Oral Impl. Res. 27, 2016 / 39–46

Fig. 2. Three-dimensional micro computed tomography reconstruction of allogenic bone modeled on an inverted “L”.



Fig. 3. Recipient bed and checking mandibular thickness.

Fig. 5. Mandibular thickness after graft installation.

Fig. 4. Recipient bed with perforations.

thickness flap was raised and mobilized for tension-free closure. The cortical buccal wall of the recipient native bed bone was perforated (Fig. 4). FFB bone blocks were L-shaped using a round diamond bur and a micro saw (Fig. 1). The cancellous portion of the prepared block was passively adapted over the alveolar defect and fixed in position with 1.5 9 10 mm titanium screws (Synthes, Oberdorf, Switzerland) (Fig. 5). All blocks were perforated on the cortical external face. The sharp cortical edges were rounded, and BBM granules 0.25–1 mm (Bio-Oss, Geistlich Pharma, Basel, Switzerland) were used to cover the block and proximal areas (Fig. 6). Then, resorbable membranes (BioGide, Geistlich Pharma) were used to cover the BBM (Fig. 7). Internal periosteal release of the buccal flap and partial detachment of the lingual mylohyoid muscles were performed to allow for passive sutures before wound closure. The grafted sites were allowed to heal for 6 months postoperatively, and no provisional restorations were permitted. A trephine bur was used to collect cylindrical samples (n = 12) from the graft during titanium implant placement for histological examination. Thirty cone morse rough surface titanium implants (Titamax CM cortical,

Neodent, Curitiba, Brazil) were placed (Fig. 8). Patients underwent prosthetic rehabilitation 6 months after placing the implant (Fig. 9). Volumetric evaluation

The CBCT analysis was conducted 1 week after grafting surgery (T1) and 6 months postoperatively (T2) using the CBCT model iCat Classic (Imaging Sciences International, Hatfield, EUA) with exposure factors of 120 KV and a mAs of 36.12 on a 0.25 mm reconstruction interval and slice thickness. The tomography images were analyzed with Mimics software ver. 8.13 (Materialise, Leuven, Belgium) in DICOM files to assess discrepancies between graft volumes at different experimental times (T1 and T2). Linear changes in height were evaluated by Dental Slice (Bioparts, Brasilia, Brazil). The descriptive presentation of the data includes mean standard deviation (SD). Histological procedure Resin

Biopsies were fixed in 10% formalin (pH 7) for 10 days. The specimens were dehydrated in an ascending alcohol series, where they


Fig. 6. Bovine bone mineral (BBM) covering the graft.

remained for 48 h at each concentration (70%, 80%, 96%, 100%). The samples were embedded in LR White resin (London Resin Co., London, UK) and kept under stirring for 60 min. Subsequently, the specimens were stored and maintained for at least 12 h at 4°C. Then, they were placed in a vacuum for 1 h, agitated for 1 h, and stored at 4°C for

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Fig. 10. Bone height changes.

using a combination of Stevenel’s blue and Alizarin Red-S (Maniatopoulos et al. 1986). Paraffin

Fig. 7. BioGideâ collagen membrane.

24 h. This routine was repeated for 15 days, with the resin changing every 48 h. The resin in the biopsies was induced to polymerize at 60°C. The specimens were bisected longitudinally using a 0.1 mm/D64 precision bandcutting saw (EXAKT, Norderstedt, Germany) and sanded and polished on sandpaper and polishing cloths with different granulations

Fig. 9. Occlusal view 22 months after prosthetic loading.

starting at 320, followed by 800, 2500, and 4000 (Hermes Abrasives Ltd, Virginia Beach, VA, USA). Two pieces (slices) with a thickness of approximately 90 lm were obtained from each trephine for staining and observation under a light microscope and stained

Bone biopsies that passively came from the trephines were fixed in 10% buffered formalin at pH 7.4 (for at least 24 h). After fixation, the specimens were decalcified in 4% EDTA (ethylenediaminetetraacetic acid) and changed once per week. The bone pieces were washed in running water for about 1 h, followed by dehydration through an alcohol series with increasing concentrations (50–100% for 2 h). Diaphanization was performed after dehydration by placing the pieces in xylene (three solutions for 2 h) until transparent. The fragments were impregnated with paraffin in an oven at 60°C in three baths at 3 h each. The parts were shaped in paraffin wax, which hardened with the totally soaked parts. The pieces were placed in paraffin longitudinally for full assessment of the specimen under a microscope. The paraffin blocks were cut with a microtome using the standard 5 mm thickness and were divided in an interleaved manner for histological analysis with hematoxylin and eosin (H&E). Two of the best stained samples of each biopsy were chosen for evaluation. Histology and histomorphometry

Fig. 8. Panoramic radiography; bone level maintenance around an implant after 22 months loading.

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We collected bone trephine samples from 12 patients for histomorphometric analysis of the 30 blocks grafted. Only one sample per patient was allowed, following the ethical committee guidelines. Measurements were carried out at a 109 magnification. A Leica DMLB Microsystems microscope with a Leica DC300F digital camera (Leica Microsystems, Hesse, Germany) connected to a computer with Leica Application suite v4.1 software was used for histomorphometric measurements. Sections stained with Stevenel’s blue and Alizarin Red-S or H&E were used to measure connective tissue (CT), new bone formation (NB), and residual graft (RG), © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd


Volumetric evaluation

Graft absorption was 45% for height (Fig. 10) and volume (Fig. 11), and both measures were significantly different (P < 0.001; Wilcoxon’s signed-rank test). The median volumetric difference between T1 and T2 was 461.10, with a mean of 529.51 275.83 cm3. The median height difference between T1 and T2 was 1.34, with a mean of 2.2 1.8 mm. Histology Fig. 11. Bone volumetric changes.

delimited manually according to the tissue characteristics. Three distinct sections were measured at a 109 magnification from each biopsy, and the values were averaged. The image capture system consisted of a light microscope (Carl Zeiss, Zena, Germany) adapted to a high-resolution camera (Carl Zeiss AxioCam). The images were evaluated by REL Axion Vision 4.6 image analysis software (Carl Zeiss, Zena, Germany). The total fraction was calculated as a percentage of the total tissue volume according to a procedure described previously (Parfitt et al. 1987). The descriptive presentation of the data includes mean SD.

Newly formed vital bone, residual cancellous allograft bone, and CT were observed in all specimens. Residual cancellous block allograft bone was identified by empty lacunae. Newly formed bone containing viable osteocytes showed intimate contact with the residual cancellous block allograft bone. Osteoblasts were seen in intimate contact with newly formed bone around the residual cancellous allograft bone. No evidence of acute (neutrophils and macrophages with tissue destruc-

tion) or chronic inflammatory infiltrate (inflammatory mononuclear cells with tissue destruction) was observed (Figs 12 and 13). Histomorphometry

Histomorphometry showed 18.9 8.1% NB formation, 32.5 14.8% RG, and 48.6 14.9% CT (Figs 13 and 14, Table 1). BBM was found in just one histological analysis (Fig. 15); however, it was in the superficial portion of the biopsy cylinder and not considered for analysis, as the beginning and end of the trephine bur usually fragments making it impossible to evaluate those regions. Therefore, only the middle third was evaluated.

Discussion Few studies have used fresh-frozen allogenic bone blocks for alveolar augmentation in the posterior mandible (Carinci et al. 2009;

Results Clinical results

Sixteen hemi-mandibles from twelve patients (nine females and three males; age range, 37– 64 years; mean, 50.9 8.3 years) were selected for FFB grafting and implant-supported restoration of the posterior atrophied mandible. No bone block was lost, and all implants were installed. The blocks showed well-vascularized integrated bone to the recipient bed at 6 months. Because the mucoperiosteal flap allowed for a large amount of tissue dislocation by the buccal and lingual surfaces after completing the relaxing incision of the mylohyoid muscle, passive accommodation of the soft tissues was allowed. Small expositions of the graft were detected in four patients, and all of them were treated with 2% chlorhexidine gel until spontaneous closure, which occurred within 10 days. Postoperative thickness and high bone gain were 4.5 1.3 mm and 2.6 2 mm at 6 months, respectively. The quality of the bone obtained was sufficient to allow an implant insertion torque of 44.8 6.8 N, and the implant survival rate was 29 of 30 (96.6%) after 26 4.1 months (range, 22.2–34.8 months) of follow-up.

Fig. 12. Intimate contact between allograft bone (RG) with extensive areas of newly formed bone (NB) and different degrees of mineralization and connective tissue (CT) (Stevenel’s blue and Alizarin Red-S). Magnification, 209.

Fig. 13. Histological view (hematoxylin and eosin), showing intimate contact between residual bone allograft (RG) and newly formed bone (NB). Magnification, 109.


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Fig. 14. Same histological section as in Fig. 13. Presence of newly formed bone (NB), allogenic bone (RG), and connective tissue (CT). Magnification, 109.

Table 1. Clinical data and histomorphometry of new bone formation (%), allogenic bone (%), and connective tissue (%)

Patient 1 Patient 2 Patient 3 Patient 4 Patient 5 Patient 6 Patient 7 Patient 8 Patient 9 Patient 10 Patient 11 Patient 12 Median Mean SD

Gender

Age

New bone formation

F M F F F M F F F F M F – – –

64 52 46 47 54 37 52 58 51 52 37 61 52 50.9 8.3

14.9 17.3 39.1 16.3 14.9 7.2 22.6 15.9 25.8 14.3 14.6 23.9 16.1 18.9 8.1

Residual allograft

Connective tissue

26.9 73.8 19 42.9 36.1 27.3 20.2 24.2 32.7 36.8 25.9 24.3 27.1 32.5 14.8

58.2 8.9 41.9 40.8 49 65.5 57.2 59.8 41.5 48.9 59.5 51.8 50.4 48.6 14.9

Fig. 15. Bovine bone mineral (BBM) in the superficial area of the graft. Osteoclast (dark arrow), osteoid bone formation (yellow arrows), and connective tissue (CT). Magnification 409.

Macedo et al. 2012; Chiapasco et al. 2013; Pimentel et al. 2014). This study was designed to evaluate whether corticomedullary grafts in

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FFB blocks could be used for bone augmentation and maintenance of graft volume in atrophied posterior human mandibles. The

grafting enabled 3D reconstruction of the residual ridge in regions that was impossible to install dental implants due to insufficient height and/or thickness with less morbidity after avoiding the donor bed. We evaluated the clinical, histological, histomorphometric, and volumetric behavior of these grafts after 6 months. This period of evaluation was selected because other researchers (Laviv et al. 2014) have evaluated the posterior mandible at this time point and noticed that relevant differences in tissue formation could be detected. We observed that the corticomedullary allogenic bone block graft behaved as an osteoconductive biomaterial, as it allowed close contact of newly formed bone on residual allograft bone, probably due to infiltration of cells through the bone medulla. According to Giannoudis et al. (2005) and Stevenson (1999), a cancellous bone block has less structural strength compared to that of cortical bone. In contrast, cortical bone has a slow remodeling rate, whereas cancellous bone has a higher rate of revascularization. Thus, corticocancellous blocks offer the advantage of a thin layer on the outer cortical portion of the block, proper locking of the fastening screw, and increased initial graft stability. Moreover, a high number of large cancellous bone contact receptor sites are available, which allow blood/cell and infiltration of bone growth factors during osteoconduction (Marx 2007). Our grafting surgery technique resembled that described by Nissan et al. (2011a,b). However, our blocks were FFB cancellous blocks. Furthermore, the blocks were covered with BBM granules and a collagen membrane for better final conformation of the graft. Simion et al. (2007a,b) studied increasing vertical bone in the posterior mandible and noted that BBM is absorbed slowly as it is replaced by newly formed bone, as proposed by Maiorana et al. (2005). Thus, BBM participates in bone regeneration by maintaining the superficial area. We used BBM to coat the allograft blocks and proximal areas. BBM is slowly resorbed as it becomes newly formed bone (Simion et al. 2007a,b) and can remain in situ for extended periods (Mordenfeld et al. 2010). Moreover, Maiorana et al. (2005) demonstrated reduced resorption of autogenous grafts using Bio-Oss for coverage, and Morad & Khojasteh (2013) showed the effectiveness of BBM for reducing the percentage of absorption during autograft bone augmentation for the posterior mandibular region without use of a collagen membrane to guarantee guided bone regeneration. This is the first report to use the Bio-Oss and fresh-frozen bone, which



resulted in good clinical outcomes. However, Bio-Oss was not measured in the histomorphometric analysis, as only the middle third of the bone sample was analyzed due to disruption of the surface. The immediate and later postoperative gains in our study were 6.3 1.4 and 4.5 1.3 mm for width, respectively, and 4.8 1.6 and 2.6 2 mm for height, respectively. These results are in accordance with those by Nissan et al. (2011a,b), who observed an average horizontal and vertical gain of 5.6 mm and 4.3 mm, respectively, in the posterior mandible using FDBA. Similarly, Macedo et al. (2012) evaluated the vertical gain of maxillo-mandibular FFB blocks 7 months after surgery and observed an average height gain of 4.03 1.69 mm. Thus, FFB, as used in the present study, was a good choice to maintain 3D bone form. The grafts became viable for placing an implant 6 months after grafting. At the time of reopening to place the implant, all blocks had good vascularization and bleeding after drilling, as previously described (Contar et al. 2009; Deluiz et al. 2013). The blocks allowed the implants to be inserted with an average torque of 44.8 N, enabling good primary stability, in agreement with previous studies (35–40 N) (Contar et al. 2009; Acocella et al. 2012; Macedo et al. 2012; Deluiz et al. 2013). This result indicates that FFB grafts enable osseointegration of a dental implant independently of cellularity. We obtained an implant placement success rate of 96.6% in an evaluation period of 15.3– 28.7 months. Other studies have shown a similar high success rate of osseointegration,

varying from 95.3 to 100% (Holmquist et al. 2008; Contar et al. 2009; Morelli et al. 2009; Nissan et al. 2011a,b; Novell et al. 2012; Pimentel et al. 2014). However, among those previous studies, some (Holmquist et al. 2008; Contar et al. 2009; Novell et al. 2012) studies used this technique on the maxilla; thus, it is difficult to make a direct comparison, as maxillary bone has greater vascularization and the FFB has a greater chance to integrate at the recipient site. The histological analysis 6 months after grafting showed NB formation, residual acellular allograft, and CT without inflammatory tissue. The NB area was in close contact with allogenic bone, and empty osteocyte lacunae were found in residual bone, similar to other reports (Proussaefs & Lozada 2005; Holmquist et al. 2008; Contar et al. 2009; Morelli et al. 2009; Waasdorp & Reynolds 2010; Nissan et al. 2011a,b). Similar results were found in allogenic fresh-frozen residual bone 6 months after grafting (Spin-Neto et al. 2013). Other researchers (Chiapasco et al. 2013) consider this necrotic bone; however, we disagree due to the absence of bone sequestration and pain; hence, the use of allograft and BBM remained, at least, as a bone graft and acted like a scaffold to osteoblasts. This is the first study that performed histological and histomorphometric analyses to assess the biological and clinical behavior of FFB bone blocks specifically in the mandibular posterior region. The fresh-frozen allograft blocks behaved as an osteoconductive material, as close contact of NB with residual allograft bone was observed during our evaluation. The mean percentage of NB was

18.9%, with 32.5% residual allograft bone (total bone = 51.4%) and 48.6% CT. FDBA in the posterior mandible generates a rate of 44% NB and 29% RG (Nissan et al. 2011a,b). The different NB formation percentages could be a consequence of bone formation at different graft types (FFB 9 FDBA) or architecture (trabecular bone patterns in spongiosa).

Conclusion Corticocancellous FFB blocks from the distal femoral epiphysis permitted bone formation and behaved as a scaffold for osteoconduction. These blocks are a viable alternative for reconstructing an atrophied mandible in the posterior region, allowing implant installation and prosthetic rehabilitation with a high success rate. Long-term studies employing this technique are desirable to provide data about implant success rates and bone resorption. The English in this document has been checked by at least two professional editors, both native speakers of English. For a certificate, please see: http://www.textcheck.com/ certificate/zwLCOZ

Acknowledgements: This study was supported by grants from FAPESP (2012/ 14971–5). We thank Professor Paulo Tambasco de Oliveira for the histological and histomorphometric analyses and Adriana Luisa Goncßalves Almeida, Dimitrius Leonardo Pitol, and Sebasti~ao Carlos Bianco for laboratory technical support.

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Horizontal Resorption of Fresh-Frozen Corticocancellous Bone Blocks in the Reconstruction of the Atrophic Maxilla at 5 Months.

Complications when augmenting the posterior maxilla.

Arthroscopic distal tibial allograft augmentation for posterior shoulder instability with glenoid bone loss.

Implant treatment in atrophic posterior mandibles: vertical regeneration with block bone grafts versus implants with 5.5-mm intrabony length.

Thumb proximal phalanx reconstruction with nonvascularized corticocancellous olecranon bone graft.

Vertical ridge augmentation of the atrophic posterior mandible with sandwich technique: bone block from the chin area versus corticocancellous bone block allograft--clinical and histological prospective randomized controlled study.

Volumetric Stability of Fresh Frozen Bone Blocks in Atrophic Posterior Mandible Augmentation.

Autogenous cancellous-marrow bone grafts in irradiated dog mandibles.

Compact bone distribution and biomechanics of early hominid mandibles.

Biomechanical Evaluation of Posterior Cruciate Ligament Reconstruction With Quadriceps Versus Achilles Tendon Bone Block Allograft.

Bone strain following application of a rigid bone plate: an in vitro study in human mandibles.

Crestal bone resorption in augmented bone using mineralized freeze-dried bone allograft or pristine bone during submerged implant healing: a prospective study in humans.

Long-term outcomes of the use of allogeneic, radiation-sterilised bone blocks in reconstruction of the atrophied alveolar ridge in the maxilla and mandible.

Dynasore blocks evoked release while augmenting spontaneous synaptic transmission from primary visceral afferents.

Allograft Bone as Antibiotic Carrier.

Surgical revascularization in structural orthotopic bone allograft increases bone remodeling.

Temperature Values Variability in Piezoelectric Implant Site Preparation: Differences between Cortical and Corticocancellous Bovine Bone.

HIV inactivation in a bone allograft.

Perovskite ceramic nanoparticles in polymer composites for augmenting bone tissue regeneration.

Rehabilitation of the severely atrophied dentoalveolar ridge in the aesthetic region with corticocancellous grafts from the iliac crest and dental implants.

Overlapping allograft for primary or salvage bone tumor reconstruction.

Combining bisphosphonates with allograft bone for implant fixation.

Midterm results of treating femoral head osteonecrosis with autogenous corticocancellous bone grafting.

Cortical tenting technique versus onlay layered technique for vertical augmentation of atrophic posterior mandibles: a split-mouth pilot study.