Bone Graft Volume Research Articles

Evaluation of Volumetric Changes of Augmented Maxillary Sinus With Different Bone Grafting Biomaterials.

Extensive alveolar bone resorption because of pneumatized maxillary sinus is a common problem that limits dental implant placement. Maxillary sinus floor augmentation (MSFA) is an accepted treatment protocol that provides sufficient bone volume. The aim of this study was to evaluate the percentage of graft volume reduction following MSFA using cone beam computed tomography. In this retrospective study, cone beam computed tomography scans of MSFA were measured to evaluate the volume of the grafted sinus with deproteinized bovine bone (DBB), mineralized allograft (MA), or a mixture of MA and demineralized allograft as a composite. The volumetric changes in sinus augmentation between 2 weeks (T-I) and 6 months (T-II) after operation were analyzed. Thirty-nine patients were included in this study. The average percent volume reduction was 8.14 ± 3.76%, 19.38 ± 9.22%, and 24.66 ± 4.68% for DBB, MA, and composite graft, respectively. A significant graft volume reduction was found between T-I and T-II for all groups (P < 0.01). The DBB group showed the least volume reduction (P < 0.01). Biomaterials can influence the bone graft volume change before implant placement. Deproteinized bovine bone may offer greater volume stability during healing than mineralized and composite allografts.

Use of Supercritical Sterilized Bone Allograft in Two Stage Revision ACL Reconstruction

Objectives:Revision ACL-reconstruction can be compromised by bone loss as result of tunnel widening or poorly placed tunnels. Two-stage revision ACL consist of initial removal of the old fixation hardware and remaining ACL-graft tissue, followed by bone grafting of the tunnels. After a period of graft incorporation and bone remodeling, an ACL-reconstruction is performed. Our primary aim is to examine the use of supercritical carbon dioxide sterilized bone allograft for tunnel grafting in order to determine the bone quality, graft incorporation and remodeling, by using histology and histomorphometric analysis. Secondarily, we aimed to determine whether the histological findings correlate with the timing of the second stage revision procedure.Methods:Case Series. 12 subjects underwent 2-stage revision ACL reconstruction. Femoral and tibial tunnels were bone grafted with supercritical carbon dioxide sterilized bone allograft (Australian Biotechnologies). Mean time from bone grafting to 2nd stage was 8.8 months (range, 5.6 to 21.3 months). Bone biopsies were taken at the time of the 2nd surgery and decalcified and embedded in paraffin. Sections were hematoxylin and eosin stained for microscopic analysis.Results:The graft material was easily identified by its necrotic appearance with empty osteocytes lacunes within the lamellar trabecular bone. In all tissue samples predominately lamellar host bone apposition was seen on the surface of graft fragments known as creeping substitution. Separate bone graft fragments were bridged by newly formed woven bone. In the histological sections of 2 subjects some small islands of chondral cell differentiation were seen, which may relate to endochondral ossification. Active bone remodeling and resorption through combined osteoclastic and osteoblastic activity was present in 2 subjects (7.0 and 6.3 months post grafting), suggesting more advanced phases of graft incorporation. Mean bone volume was 68% over tissue volume (range 33-92%), and graft volume over bone volume was 41% (range 19-70%). Subgroup analysis for graft volume to time of second stage could not demonstrate a difference in 6 to 9 months (mean 44%, range 19-70 %) and >10 months (mean 34%, range 19-48%).Conclusion:The osteoconductive supercritical sterilized bone allograft acted as an effective structural framework, allowing for successful graft incorporation through creeping substitution. Although cancellous grafts may remodel completely with time, the initial bone apposition on and bridging of graft fragments provides early mechanical strengths to facilitate 2-stage revision ACL reconstruction. Bone volume and graft volume varied among subjects, but no beneficial effect was demonstrated for graft incorporation and bone remodeling in delaying the 2nd stage procedure for more than 6 months.

Demineralized Bone and BMPs: Basic Science and Clinical Utility

The clinical demand for bone void fillers led to the development of off-the-shelf banked bone and synthetic and biologic substitute materials to be used either alone or as bone graft volume extenders. Demineralized bone (DB) has a remarkable capacity to induce new bone formation even when implanted subcutaneously in experimental animals, a phenomenon termed "osteoinduction." DB products are now widely available through tissue bank procurement of bone from rigorously screened donors. When properly processed, DB products are useful in craniomaxillofacial, oral, hand, and orthopedic applications. The isolation of proteins believed to be responsible for the osteoinductive activity of DB, termed bone morphogenetic proteins (BMPs), led to the cloning of a family of genes and synthesis of recombinant human BMPs (rhBMPs). They have been approved for distribution and use in specific maxillofacial and orthopedic applications. Clinical trials and studies of orthopedic and craniofacial applications have indicated that supraphysiologic doses of a single recombinant protein are needed to promote bone repair. Information about the biology, chemistry, and actions of rhBMPs and DB has called into question whether a single recombinant BMP would result in clinically useful bone induction and morphogenesis. Compelling preclinical and specific clinical evidence has indicated the efficacy of DB and for rhBMPs either combined with autograft or compared with an autograft alone. In light of questions about potency and safety, however, additional high-level evidence is needed for specific clinical indications and appropriate patient populations that would benefit from their use.

Evaluation of success of alveolar cleft bone graft performed at 5 years versus 10 years of age.

Although alveolar cleft bone grafting is the most widely accepted approach, controversies remain on the operative timing. A consecutive retrospective series of 28 patients who received alveolar bone grafting was examined and divided into 2 groups depending on the age at the time of bone graft. Group A (14 patients) was operated at a mean age of 5.2 years [range, 4-7] and Group B (14 patients) at a mean age of 10 years [range, 8.5-13]. All the children were assessed clinically and by Cone Beam Computed Tomography (CBCT) before bone grafting and 6 months post-operatively. Cleft and bone graft dimensions, volumes were assessed using Osirix v.3.9.2. Residual bone graft coefficient (Bone Graft Volume on 6-months Postoperative CBCT/Alveolar Cleft Volume) was calculated. Complications, tooth movement or dental agenesis were also reported. The sample was uniform within both groups, considering cleft forms, pre-surgical fistula rate and cleft volume. Residual bone graft coefficient reached 63.3% in Group A and 46.2% in Group B (p = 0.012). Results of residual bone graft are also influenced by tooth eruption through the graft (p = 0.007 in Group A and p = 0.02 in Group B). This 3D analysis highlighted higher success of alveolar bone grafts when children are operated earlier around 5 years. Therapeutic study. Level III/retrospective comparative study.

EACMFS Prizes and Awards

To describe a new glenoid fossa bone graft technique, and to evaluate its effect on the stability of stock fossa prosthesis implantation in total alloplastic joint replacement surgery.Eight patients who underwent total joint replacement surgery with a Biomet stock prosthesis (Biomet, Warsaw, IN, USA) from November 2013 to April 2014 were included in this study. ProPlan CMF 1.4 software (Materialise NV, Leuven, Belgium) was used to choose the prosthesis size and place it in the right position. The depth of the fossa was measured, and the osteotomy line was designed to cut the bone which overlapped the fossa prosthesis. A bone graft, taken from the bottom of the articular eminence or the condylar neck, was used to fill in the fossa and make a flat plane in combination with the residual eminence for the positioning of the fossa prosthesis. The stability of the fossa prosthesis was evaluated both intra-operatively and postoperatively with computed tomography (CT) scanning after at least 6 months of follow-up. The bone contact area of the fossa prosthesis and the volume of the grafted bone were measured.Fossa prostheses were intra-operatively stable after bone grafting. All patients had stable occlusion after surgery and at follow-up. Postoperative measurement showed that the bone contact area with the fossa prosthesis increased from 52.8% to 88.5% after bone grafting. Postoperative CT measurements (at an average of 9 months after surgery) showed that the bone graft volume decreased by 11.1%.Bone grafts in the glenoid fossa help to improve the stability of Biomet stock fossa prosthesis implantation.

Accurate Evaluation of Cone-Beam Computed Tomography to Volumetrically Assess Bone Grafting in Alveolar Cleft Patients.

The aim of this study was to investigate the accuracy of cone-beam computed tomography (CBCT) to assess the volume of bone graft in alveolar cleft patients. Twelve patients of unilateral alveolar cleft were included in this study. All patients were taken CBCT preoperative and 1 week postoperative. The digital imaging and communications in medicine (DICOM) files were imported into Simplant software and three-dimensional (3D) reconstruction of the alveolar defect was achieved. With 3D volumetric measurements module, the volume of alveolar cleft was calculated preoperatively. During operation, the syringe compression method was adopted to calculate the actual amount of bone graft. One week postoperative, CBCT scan was performed again to measure the bone volume grafted to the defect. The volumetric ratio of the syringe compression method to preoperative CBCT assessment and the volume difference between syringe compression method and postoperative CBCT assessment were analyzed to evaluate the accuracy of CBCT measurement. The 3D structure of the alveolar cleft and the boundary of bone graft was clear from CBCT images. The estimated volume of alveolar cleft by preoperative CBCT scans was 1.06 ± 0.09 cm, and the actual amount of bone graft determined by the syringe compression method was 1.51 ± 0.12 cm. The ratio between the latter to the former was 1.43 ± 0.07. The calculated volume of bone graft by 1-week postoperative CBCT scans was 1.53 ± 0.11 cm, with no significant difference compared with the actual amount of bone graft (P > 0.05). CBCT was an accurate measurement to calculate the volume of alveolar defect and bone graft in alveolar cleft patients. Preoperative scans could aid in quantitatively determining the bone amount needed to adequately fill the bone defect, and the postoperative scans give accurate follow-up evaluation after surgery.

Application of fossa bone graft to stabilize stock total joint prosthesis in temporomandibular joint surgery.

To describe a new glenoid fossa bone graft technique, and to evaluate its effect on the stability of stock fossa prosthesis implantation in total alloplastic joint replacement surgery. Eight patients who underwent total joint replacement surgery with a Biomet stock prosthesis (Biomet, Warsaw, IN, USA) from November 2013 to April 2014 were included in this study. ProPlan CMF 1.4 software (Materialise NV, Leuven, Belgium) was used to choose the prosthesis size and place it in the right position. The depth of the fossa was measured, and the osteotomy line was designed to cut the bone which overlapped the fossa prosthesis. A bone graft, taken from the bottom of the articular eminence or the condylar neck, was used to fill in the fossa and make a flat plane in combination with the residual eminence for the positioning of the fossa prosthesis. The stability of the fossa prosthesis was evaluated both intra-operatively and postoperatively with computed tomography (CT) scanning after at least 6 months of follow-up. The bone contact area of the fossa prosthesis and the volume of the grafted bone were measured. Fossa prostheses were intra-operatively stable after bone grafting. All patients had stable occlusion after surgery and at follow-up. Postoperative measurement showed that the bone contact area with the fossa prosthesis increased from 52.8% to 88.5% after bone grafting. Postoperative CT measurements (at an average of 9 months after surgery) showed that the bone graft volume decreased by 11.1%. Bone grafts in the glenoid fossa help to improve the stability of Biomet stock fossa prosthesis implantation.

A perfusion bioreactor system efficiently generates cell-loaded bone substitute materials for addressing critical size bone defects.

Critical size bone defects and non‐union fractions are still challenging to treat. Cell‐loaded bone substitutes have shown improved bone ingrowth and bone formation. However, a lack of methods for homogenously colonizing scaffolds limits the maximum volume of bone grafts. Additionally, therapy robustness is impaired by heterogeneous cell populations after graft generation. Our aim was to establish a technology for generating grafts with a size of 10.5 mm in diameter and 25 mm of height, and thus for grafts suited for treatment of critical size bone defects. Therefore, a novel tailor‐made bioreactor system was developed, allowing standardized flow conditions in a porous poly(L‐lactide‐co‐caprolactone) material. Scaffolds were seeded with primary human mesenchymal stem cells derived from four different donors. In contrast to static experimental conditions, homogenous cell distributions were accomplished under dynamic culture. Additionally, culture in the bioreactor system allowed the induction of osteogenic lineage commitment after one week of culture without addition of soluble factors. This was demonstrated by quantitative analysis of calcification and gene expression markers related to osteogenic lineage. In conclusion, the novel bioreactor technology allows efficient and standardized conditions for generating bone substitutes that are suitable for the treatment of critical size defects in humans.

Is Canine Eruption Velocity Affected by the Presence of Allograft Within a Repaired Alveolar Cleft?

To assess the rate of canine eruption in alveolar clefts repaired with cancellous autograft versus cancellous autograft mixed with allograft. This was a retrospective cohort study of patients in mixed dentition who underwent primary repair of uni- or bilateral alveolar cleft defects. Patients were divided into 2 groups based on the method of bony reconstruction (group 1, iliac crest autograft; group 2, iliac crest autograft harvested through a minimal access approach and mixed 1:2 with demineralized bone allograft). Secondary predictor variables were demographic and anatomic factors potentially related to canine eruption. The outcome variable was the velocity of canine eruption, measured as the change in vertical distance from the incisal edge to the maxillary occlusal plane (millimeters per month). Descriptive, bivariate, and linear regression statistics were computed. The study sample included 57 alveolar cleft defects; 19 were repaired with autograft alone and 38 were repaired with autograft plus allograft. The sample's mean age was 9.9 ± 2.3 years at the time of repair. Thirty-one clefts (54.4%) were part of a bilateral deformity. Canine root formation was 50% complete at the time of surgery in most patients (59.6%). Mean duration of follow-up was 23.7 ± 13.2 months. Mean canine eruption velocity was 0.20 ± 0.18 mm per month and was not associated with the method of bony repair (P = .58). The use of allograft bone to augment bone graft volume results in similar rates of canine eruption compared with autograft bone alone.

Osseous and dental outcomes of primary gingivoperiosteoplasty with iliac bone graft: A radiological evaluation

Primary alveolar cleft repair has two main purposes: to restore normal morphology and normal function. Gingivoperiosteoplasty with bone grafting in mixed dentition has been a well-established procedure. We hypothesized that 1) performance of this surgery in deciduous dentition would provide favorable bone graft osseointegration, and 2) would improve the support of incisor teeth eruption, thereby avoiding maxillary growth disturbances. We conducted a retrospective study of clinical and tridimensional radiological data for 73 patients with alveolar clefts (with or without lip and palate clefts) who underwent gingivoperiosteoplasty with iliac bone graft in deciduous dentition. Pre- and post-operative Cone Beam Computed Tomography (CBCT) comparison allowed evaluation of the ratio between bone graft volume and initial cleft volume (BGV/ICV ratio), and measurement of central incisor teeth movements. This series of 73 patients included 44 males and 29 females, with a mean age of 5.5 years. Few complications were observed. Post-operative CBCT was performed at 7.4 months. The mean BGV/ICV ratio was 0.62. Axial rotation was significantly improved post-operatively (p = 0.004). Gingivoperiosteoplasty with iliac bone graft is safe when performed in deciduous dentition and results in a sufficient bone graft volume to support lateral incisor eruption and upper central incisor tooth position improvement.

Correction de l’énophtalmie post-traumatique par greffe osseuse : pourquoi des résultats inconstants ?

Posttraumatic enophthalmos cause complex cosmetic problems to fix. In order to get better results, we wanted to calculate the volume of parietal bone graft needed to be put in place, know where to place it in orbit and study soft tissues' participation. In a retrospective study, we have calculated on scanner the volume of bone and soft tissue as well as the volume and the location of the graft. We have compared, between two groups ("good result" and "insufficient result"), graft volumes, taking into account differences in bone's volume between the healthy and the traumatized orbit. A comparison of the locations of the graft was also made. We were trying to find out if these factors were involved in the quality of the result. Twenty-nine surgeries on 24 patients were analyzed. The average bone's volume of an orbit with enophthalmos was 24.76 cm(3) for 17.12 cm(3) of soft tissue. Retro-lens distance was the most reliable measurement method of enophthalmos (P=0.001). There was a trend to a more substantial over-correction in the group "good result". A significant increase (P=0.0008) of soft tissue volumes in the traumatized orbit was found. This last result is surprising. Many authors believe that there is a scar retraction of soft tissues. But Kronish et al. showed an increase of the fat density and connective tissue. This, together with the assumption of a weathering of the ligament suspension of the globe, may affect our aesthetic results. MRI, ultrasound and anatomopathological studies would allow a better understanding of the fat, muscle and ligament pathophysiologies of an orbit with enophthalmos.

Onlay bone graft maintenance using guided bone regeneration, platelet rich plasma, and their combination.

Onlay bone grafts have a bad reputation of resorption with loss of contour and volume. Rigid fixation reduces the incidence of resorption but does not prevent it. Literature shows reduction of resorption by applying guided bone regeneration (GBR) barriers and platelet-rich plasma (PRP). Investigating the effect of combining them together to reduce resorption was the aim of this study. This study included 4 groups: control group, GBR group, PRP group, and GBR + PRP group. Twenty rabbits were used (40 mandibular halves). Onlay bone grafts were fixed by titanium miniscrews in all groups. Computed tomography scans of harvested mandibles after euthanasia allowed calculations of bone graft volume and density. Onlay bone graft volumes in all experimental groups were significantly higher than in the control group. Volume maintenance in the GBR group was significantly higher than in the PRP group. There was no significant difference in the volume of onlay bone grafts between the group of combined GBR + PRP and GBR alone. It was concluded that, to maintain the volume of onlay bone grafts, either GBR or PRP can be added. Combining them did not add any advantage over the GBR alone.

Effect of graft shape in lateral column lengthening on tarsal bone position and subtalar and talonavicular contact pressure in a cadaveric flatfoot model.

Lateral column lengthening (LCL) has been used for correction of flatfoot deformity. The purpose of this study was to determine the effect of LCL graft shape on tarsal bone position and talonavicular and subtalar joint pressure. A flatfoot model was created in 6 cadaveric specimens. Corrective LCL was performed using a rectangular graft or a trapezoidal graft with the broad surface oriented dorsally, laterally, or plantarly. Bony surface markers were digitized to calculate angular parameters used in the evaluation of flatfoot deformity. Contact pressure and area in the subtalar and talonavicular joints were also recorded. All measurements were carried out under multiple axial loads in the intact and flatfoot conditions, and following LCL with each graft shape. Flatfoot creation resulted in significant changes in arch collapse and forefoot abduction. LCL with a rectangular graft best corrected these parameters, while a laterally oriented trapezoidal graft provided some correction. Talonavicular contact pressure was unchanged after flatfoot creation, and was significantly less than intact after LCL. Subtalar contact pressure decreased in some conditions after flatfoot creation, and decreased further after LCL. LCL with a rectangular graft best restored tarsal bone orientation in a cadaveric flatfoot model. The decreases in talonavicular pressure likely represent redistribution of force from the medial to lateral foot. When performing LCL for flatfoot deformity, increased bone graft volume medially better restores tarsal bone position. One way of achieving this is through the use of a rectangular graft as opposed to a trapezoidal graft.

Fusion rate according to mixture ratio and volumes of bone graft in minimally invasive transforaminal lumbar interbody fusion: minimum 2-year follow-up.

Hydroxyapatite (HA) is commonly used as bone substitute in clinical practices. However, only few studies have compared the relationship between the mixture ratio of bone graft in the actual clinical field and fusion rate according to bone graft volume. The study aimed to analyze the fusion rate according to the mixture ratio and the amount of bone graft in minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). A total number of 88 subjects who completed a 2-year follow-up after MI-TLIF participated in this study. Subjects were divided into three groups: Group 1 with local autograft, Group II with a mixture of HA and autobone of over 50%, and Group III with a mixture of HA and autobone of less than 50%. Subjects were also grouped into two groups: Group A with a graft volume of less than 12 ml and Group B with more than 12 ml. The correlation of mixture ratio and the graft volume with fusion rate was analyzed. For clinical analysis, visual analogue scale for pain and Oswestry Disability Index were used. Bone integration was evaluated based on the classification methods described in the Burkus study. Fusion rates are increased according to the ratio of autograft in all groups: 90.9% in Group I, 87.8% in Group II, and 85.7% in Group III. However, there were no significant differences between groups (p = 0.22). The fusion rates significantly increased as the amount of bone graft increased to over 12 ml, showing 81.5% in Group A and 92.0% in Group B (p = 0.03). A high rate of fusion was achieved in MI-TLIF in graft volume of more than 12 ml. We therefore recommend at least 12 ml of bone graft volume for successful fusion.

Endoscopic lift of the maxillary sinus floor in beagles

The aim of this study was to introduce a modified endoscopic lift of the floor of the maxillary sinus in beagles. Twelve operations (bilateral and randomly chosen) were done in 6 beagles each in the test group (modified endoscopic operation), and the control group, in which the operation was done with an osteotome. All operations were evaluated by two indices of safety (perforation of the sinus membrane and nasal bleeding) and 3effective indices (the intraoperative height after lifting, volume of bone grafts, and dislocation of the sinus grafts). The sinus membrane was not perforated and there were no nasal bleeds in either group. The intraoperative height after lifting was 13.7 (0.8) mm in the test group and 9.1 (0.5) mm in the control group, so it was significantly higher in the test group than the control group (p=0.0001). Similarly, the volume of bone graft was 0.9 (0.04) ml in the test group and 0.5 (0.02) ml in the control group (p=0.0001). The volume of the anterior and posterior bone grafts in the implant cavity in the test group did not differ significantly (p=0.102), while there were significant differences in the control group (p=0.002). Endoscopic lifting of the floor of the maxillary sinus is a safe and effective approach based on direct observation in beagles.

Technique and indications for the retrograde use of the reamer-irrigator-aspirator

Background: The reamer-irrigator-aspirator (RIA; Depuy-Synthes, West Chester PA) is an industry-developed device that was developed to diminish the theoretical risks to the cardiopulmonary and skeletal system during intramedullary reaming. The indications for use of the RIA have been greatly expanded over the past decade to include debridement of medullary osteomyelitis and large-volume autogenous bone-graft harvest. The manufacturer recommends using the RIA in an antegrade fashion to ream the femoral canal. The indications for retrograde RIA have not been discussed in the literature previously. The purpose of this study is to describe the indications used for a small series of patients treated with retrograde RIA for autogenous bone graft harvest. Methods: This is a retrospective case series of three patients in whom a large volume of autogenous bone graft was obtained using the reamer-irrigator-aspirator in a retrograde fashion, a method that has not been previously reported. Results: The retrograde use of the reamer-irrigator-aspirator was a safe and effective method of obtaining an average of 37 cc of autogenous bone graft in a carefully selected small group of patients with segmental bone loss, nonunion, and obesity. Conclusions: The indications for retrograde use of the RIA device have not been previously reported in the orthopaedic literature. Our study suggests the following indications for retrograde RIA use: obesity, “violated joint” concept, and locally compromised tissue preventing antegrade reaming. Hemarthrosis within the knee is prevented by impaction of an allograft bone dowel into the reamer entry site.

Composite ceramic graft in pediatric cavitary benign bone lesions

Background In the pediatric age group, filling of some cavitary benign bone lesions (CBBL) may be problematic because of the limited available volume of autogenous iliac bone graft and donor site morbidity. Hence, synthetic materials are becoming an increasingly popular alternative or adjunct to bone graft in such situations. Patients and methods A total of 14 CBBL in 13 children (1.5-6.5 years) were managed by local curettage and the application of a composite ceramic bone substitute. The mean size of the cavitary bone lesion was 21.7 cm 2 . Patients were followed clinically and radiologically for an average of 39 months (26-51 months). Results Patients' function and parents' satisfaction with the procedure were graded as satisfactory end result in all patients. Bone healing (according to Neer et al. grading system) was 28.6% type 1, 64.3% type 2, and 7.1% type 3. Graft resorption and incorporation (according to Irwin's staging system) was 35.7% grade II and 64.3% grade III, at the latest follow-up (average 39 months). There were no major early or late postoperative complications. Conclusion Composite ceramic bone substitutes are a satisfactory option in the management of pediatric CBBL.

Three-Dimensional Volume Change of Grafted Bone in the Maxillary Sinus

The purpose of this study was to evaluate the three-dimensional radiographic changes of 100% anorganic bovine bone xenograft volume in a grafted maxillary sinus, based on a computerized analysis of cone-beam computed tomography (CBCT) scan. A maxillary sinus augmentation procedure done with a lateral approach using 100% anorganic bovine bone was performed in 20 patients. A CBCT scan of the grafted area was taken immediately after the procedure (T1) and 8 to 9 months later (T2). CBCT scan data were analyzed with image processing software to evaluate differences in the volume of grafted material between T1 and T2. Residual ridge height and width were also measured at T1. The mean residual bone height and width at the implant sites was 4.40±0.87 mm and 7.9±2.22 mm, respectively. The mean graft volume was 1,432±539 mm³ and 1,287±498 mm³ at T1 and T2, respectively. A significant difference in graft volume was found between T1 and T2 data by paired t test (P=.01). The mean ratio between the volume at T2 and the volume at T1 was 0.90±0.12, meaning a graft volume contraction of 10%. Within the limits of the present investigation, good stability of anorganic bovine bone graft volume up to 8 months after the grafting procedure was demonstrated. Three-dimensional computed tomographic volumetric assessment seems to be a promising approach to quantify long-term changes in the regenerated area.

The Volume Behavior of Autogenous Iliac Bone Grafts After Sinus Floor Elevation: A Clinical Pilot Study

Iliac crest is still regarded as one of the most viable source of autogenous graft materials for extensive sinus floor elevation. Three-dimensional resorption behavior has to be taken into account in anticipation of the subsequent insertion of dental implants. We performed 3-dimensional volume measurements of the inserted bone transplants in 11 patients (6 women and 5 men; mean age = 2.3 years) who underwent bilateral sinus floor elevation with autogenous iliac crest grafts. In order to determine the respective bone graft volumes, cone-beam computerized tomography studies of the maxillary sinuses were carried out directly after the operation (T0), as well as 3 months (T1) and 6 months (T2) postoperatively. The acquired DICOM (Digital Imaging and Communications in Medicine) data sets were evaluated using suitable analysis software. We evaluated statistical significance of graft volumes changes using a linear mixed model with the grouping factors for time, age, side, and sex with a significance level of P = .05. 38.9% of the initial bone graft volume, which amounted to 4.2 cm(3), was resorbed until T1. At T2, the average volume again decreased significantly by 18.9 % to finally reach 1.8 cm(3). The results show neither age nor side dependency and apply equally to both sexes. Without functional load, iliac bone grafts feature low-volume stability in sinus-augmentation surgery. Further clinical and animal studies should be done to detect the optimal timing for implant placement.

A novel porous bioceramics scaffold by accumulating hydroxyapatite spherulites for large bone tissue engineering in vivo. II. Construct large volume of bone grafts

In vivo engineering of bone autografts using bioceramic scaffolds with appropriate porous structures is a potential approach to prepare autologous bone grafts for the repair of critical-sized bone defects. This study investigated the evolutionary process of osteogenesis, angiogenesis, and compressive strength of bioceramic scaffolds implanted in two non-osseous sites of dogs: the abdominal cavity and the dorsal muscle. Hydroxyapatite (HA) sphere-accumulated scaffolds with controlled porous structures were prepared and placed in the two sites for up to 6 months. Analyses of retrieved scaffolds found that osteogenesis and angiogenesis were faster in scaffolds implanted in dorsal muscles compared with those placed in abdominal cavities. The abdominal cavity, however, can accommodate larger bone grafts with designed shape. Analyses of scaffolds implanted in abdominal cavities [an environment of a low mesenchymal stem cell (MSC) density] further demonstrated that angiogenesis play critical roles during osteogenesis in the scaffolds, presumably by supplying progenitor cells and/or MSCs as seed cells. This study also examined the relationship between the volume of bone grafts and the physiological environment of in vivo bioreactor. These results provide basic information for the selection of appropriate implanting sites and culture time required to engineer autologous bone grafts for the clinical bone defect repair. Based on these positive results, a pilot study has applied the grafts constructed in canine abdominal cavity to repair segmental bone defect in load-bearing sites (limbs).