Assessment of Bone Resorption after Secondary Alveolar Bone Grafting Using Three-Dimensional Computed Tomography: A Three-Year Study

Objective:

Secondary bone grafting plays an important role in the dental rehabilitation of patients with clefts of the lip, alveolus, and palate. A major complication of this surgical technique is resorption of the grafted bone transplant. Conventional two-dimensional radiographs are often inconclusive and do not demonstrate the true deficit. The main objective of this study was to evaluate the amount and exact location of bone loss on the basis of three-dimensional models over a period of 3 years.

Design:

Twenty-four patients with unilateral cleft palate were included in this prospective study. Axial computed tomography scans of all patients were taken immediately preoperatively, and 1, 2, and 3 years postoperatively. Volumetric analysis was performed on three-dimensional models of the cleft defects and the bone bridges using three-dimensional computed tomography.

Interventions:

All patients were treated by secondary alveolar bone grafting prior to eruption of the permanent canine.

Results:

Extensive bone resorption was found in the bucco-palatal dimension of the alveolar portion of the transplant. The success rate of secondary bone grafting was high in cases of rapid orthodontic gap closures. The mean bone loss in the first year after surgery was 49.5%. The transplants remained almost constant in the following 2 years.

Conclusions:

Radiographic scales based on orthopantomography only evaluate the vertical dimension of the transplants. This study, however, showed that bone resorption in the transversal dimension is clearly underestimated with conventional two-dimensional radiographs.

Microcomputed and histologic evaluation of calvarial bone grafts: a pilot study in humans

Two evaluation techniques (histology and microcomputed tomography [micro-CT]) were synergistically applied to calvarial bone graft to verify whether additional bone information can be obtained for the assessment of bone grafts. Ten extensive bone defects in the anterior and posterior maxilla or mandible involving crestal bone were treated by grafted blocks and chips of autogenous calvarial bone. The grafts were fixed with lag screws and left to heal for 4 months. No complications were observed. At surgical reentry for implant placement, a cylindric bone biopsy of both graft and native bone was retrieved and analyzed with both micro-CT and standard histology. Two- and three-dimensional (2D, 3D) micro-CT analyses allowed bone connectivity indices to be evaluated. This is useful for estimating bone strength and observing bone structure. The integration of the grafted calvarial bone with the residual bone of the recipient site was considered satisfactory. Histologic analysis allowed observations to be made at a higher resolution. Calvarial bone grafts seem to have positive effects when used as grafting materials. The application of both histologic and micro-CT techniques allows a better evaluation of grafted bone by concurrently allowing 2D and 3D visual and morphometric analysis of bone vitality, structure, turnover, and strength.

Biologic response to autogenous particulate bone graft and shaped titanium mesh in segmental mandibular defect reconstruction

PURPOSE

This study evaluated the biologic response to titanium mesh and autogenous particulate bone grafts for the reconstruction of segmental mandibular defects in a dog model.

MATERIALS AND METHODS

Unilateral 40-mm critical-sized continuity defects of the mandible were made in five beagle dogs. Titanium mesh was shaped and fixed with titanium screws in the defects. Autogenous bone was harvested from the ablated mandible and iliac crest (the ratio of cortical bone:cancellous bone was 3:1) and used to fill the mesh. Two implants were placed into each bone graft. The animals were sacrificed after 6 months. Radiographs, histologic sections, scanning electron microscopy, and energy dispersive spectroscopy were performed to evaluate bone formation and osseointegration of the implants in the reconstructed mandibles.

RESULTS

The outline of the reconstructed mandible was satisfactory, and no bone resorption was observed in the defect area. All implants showed excellent osseointegration of the grafted bone. Furthermore, the density of bone formed around the implants was higher than that seen in control samples (intact, ungrafted dog hemimandibles).

CONCLUSIONS

Shaped titanium mesh with autogenous particulate bone graft is a predictable method for restoring critical-sized continuity defects of the mandible. Simultaneous implant placement is feasible and the structure of bone formed near implants may be optimal.

Long-term block graft stability in thin periodontal biotype patients: a clinical and tomographic study

PURPOSE

To assess the esthetic and functional outcome, as well as the volume maintenance, of autogenous block grafts placed in anterior sextants of thin periodontal biotype subjects over a long-term period.

MATERIALS AND METHODS

Fifteen consecutive patients were followed up yearly for an average of 40 months after autogenous block grafting. Preoperative and postoperative cone beam computed tomographic scans were analyzed to evaluate bone volume maintenance around the implants placed in the grafted sites. Clinical parameters (mucosal recession and implant transparency through the soft tissue) were assessed at prosthesis delivery and follow-up to evaluate the esthetic outcome. Digital photographs were used to confirm clinical outcomes.

RESULTS

The average augmentation per site was 2.2 times the initial buccolingual (BL) width, and 97% of the augmented width was maintained after 3.3 years. The difference between preaugmentation and postaugmentation BL width, 3.3 versus 7.4 mm, was statistically significant (P < .0001; CI 95%: 3.4 to 4.9 mm). There was a lack of implant transparency or mucosal recession around the implants in all 15 patients after an average of 40 months.

CONCLUSIONS

Autogenous block grafting seems to be a predictable treatment modality to reconstruct alveolar ridge defects in the long term. A thin periodontal biotype did not seem to affect the volume of transplanted bone for the population studied.

Evaluation of osteoinduction properties of the demineralized bovine foetal growth plate powder as a new xenogenic biomaterial in rat

The aim of this study was evaluation of osteoinductive properties of demineralized bovine foetal growth plate in submuscular transplantation (ectopic osteoinduction) as a new xenogenic biomaterial in rat model. Demineralized bovine foetal growth plate was ectopically implanted in 18 male Sprague-Dawley rats. In 18 of the animals under aseptic conditions two submuscular pouches were created between external and internal oblique abdominal muscles in the two flanks: the right was left empty (sham) and the left was filled with 20mg of demineralized bovine foetal growth plate powder. Radiographs were taken in 2, 4 and 6 weeks after the surgery, then six animals were pharmacologically euthanized after 2, 4 and 6 weeks for histopathological evaluation. Results showed: (1) osteoinductivity of xenogenic demineralized bovine foetal growth plate powder, and (2) earlier mineralization of ectopically implanted demineralized bovine foetal growth plate in the submuscular implanted area. Our results show that submuscular implantation of xenogenic demineralized bovine foetal growth plate has osteoinductive properties in a rat model.

Alternative applications of guided surgery: precise outlining of the lateral window in antral sinus bone grafting

Computed tomography (CT) and the application of CT-based guided implant surgery allow clinicians to provide enhanced precision and accuracy in implant surgery. Because of the difficulty in transferring a patient's often complex anatomic sinus configurations, as viewed on a preoperative CT scan, into precise osteotomy cuts at antral bone graft surgery, a prototype cutting guide was developed. The surgical guide was developed through the use of CT imaging, SimPlant module Oral and Maxillofacial Surgery computer software (Materialise Dental, Glen Burnie, MD), and the stereolithographic process to precisely position the lateral window, facilitating Schneiderian membrane elevation. This report demonstrates the step-by-step method to perform precise guided sinus window preparation using computer software and a stereolithographically generated surgical guide.

Implant survival in maxillary and mandibular osseous onlay grafts and native bone: a 3-year clinical and computerized tomographic follow-up

PURPOSE

This article discusses a 3-year retrospective survey of implant clinical survival and computerized tomographic analysis of bone remodeling in atrophic alveolar crests reconstructed via various autogenous bone grafting procedures and in similar regions of native bone.

MATERIALS AND METHODS

The retrospective chart review included consecutive edentulous patients with severe alveolar crest atrophy treated between 2000 and 2002 with onlay autogenous bone grafts in the mandible and anterior maxilla (as needed) and implant insertion. Implant recipients were followed for 3 years. Defective areas were reconstructed by bone graft harvested from the chin or iliac crest. Implants in reconstructed areas were divided into two groups according to graft source. Implants in corresponding native areas served as controls. Cumulative survival rate (CSR), survival rate, and confidence interval (CI) were calculated, and linear measurements of bone remodeling around implants were assessed on computerized tomographic scans. Results were compared for statistically significant differences by Wilcoxon signed-rank test with a significance level a = .05.

RESULTS

Forty patients were treated with 109 screw-type, root-form, rough-surfaced implants inserted in 48 onlay grafts; 88 implants were placed in native bone. The implant 3-year CSRs were 98.9% (CI 96.7% to 100%) in native bone and 99.1% (CI 97.3% to 100%) in onlay grafts, irrespective of bone source. Mean resorption in the maxilla was 4.6 +/- 0.9 mm buccally and 3.8 +/- 0.8 mm palatally in areas reconstructed with chin grafts, 3.4 +/- 1.7 mm buccally and 2.6 +/- 1.4 mm palatally in areas reconstructed with iliac crest grafts, and 3.2 +/- 1.2 mm buccally and 2.1 +/- 0.9 mm palatally in native areas.

CONCLUSIONS

Similar implant CSRs were seen in native and grafted sites. Maximal implant CSR was observed in onlay grafts from the chin despite more marked linear bone remodeling in this group as compared to iliac crest grafts or native bone.

[Primary total knee arthroplasty with structural autologous bone grafting of medial tibial condyle defect in elderly patients: a preliminary report]

AIM OF THE STUDY

The aim of the study is to assess the early results of primary total knee arthroplasty with reconstruction of medial tibial condyle with autogenous bone grafting in elderly patients.

MATERIALS AND METHODS

The study was conducted on patients treated with primary total knee arthroplasty. Eight subjects (eight knees) aged 63-82 (mean, 73) with mean varus alignment 18 degress (range, 10-30 degrees) required restoration of medial tibial condyle. Autogenous bone grafting from resected joint ends was used and stabilized with cancellous screws. Patients were surveyed pre- and postoperatively with questionnaires, such as: Knee Injury and Osteoarthritis Outcome Study (KOOS) and SF-36 Health Survey, version 2. Incorporation of the bone graft were evaluated in radiographs. Subsequent folow-up assessments were performed 3, 6 and 12 months after surgery.

RESULTS

Postoperatively, mean range of motion in the knee joint improved from 99 to 124 degrees and pain relief was observed. The largest improvement in KOOS and SF-36 scores was seen for activities of daily living, pain, quality of life and physical functioning, bodily pain domains, respectively. The analysis of radiographs showed incorporation of the bone grafts with no lysis. There was no evidence of graft collapse or tibial component loosening.

CONCLUSIONS

Autogenous bone grafting is valuable material to fill defects in the proximal tibial plateau. Volume of resected grafts and incorporation time are limitations for this technique. On the basis of our observations, we presume that this method is effective in elderly patients.

Acetabular reconstruction with human and bovine freeze-dried bone grafts and a reinforcement device

BACKGROUND

This is a cohort trial (1997-2005) of 49 patients submitted to an acetabular component revision of a total hip arthroplasty, using impacted human and bovine freeze-dried cancellous bone grafts (H&FDBG) and a reinforcement device.

OBJECTIVE

To compare clinical/radiographic graft incorporation capability between cancellous bone grafts.

PATIENTS/METHODS

There were two groups: I (n=26) receiving human grafts and II (n=25) receiving bovine grafts. The average follow-up times were 55 and 49 months, respectively. Clinical analysis was based on the Merle d'Aubigné and Postel score, and the radiographic analysis involved an established score based on Conn's et al. criteria for radiographic bone incorporation.

RESULTS

No clinical/radiographic differences were found between the groups and both showed an overall rate of 88.5% and 76% of graft incorporation (p=0.424).

CONCLUSION

The results presented here are comparable to those in the literature with the use of deep-FG. Therefore, cancellous bone grafts can be safely and adequately used in acetabular component revision in total hip arthroplasty.

Clinical, radiographic, and histologic evaluation of localized ridge augmentation using a mandibular bone block

This clinical case report presents a new technique for reconstructing the vertical and horizontal dimensions of the alveolar ridge using a mandibular bone block at sites planned for single implants. Augmentation was eased with the use of a mandibular bone block, which was shaped after placement with a round bur to passively fit the dimensions of the defect, at the recipient site. After treatment, approximately 7 mm of horizontal and 3 mm of vertical augmentation were gained. Histologic observation showed that the grafted bone was well integrated with the original bone. The volume of tissue gained was sufficient for placing an implant in an optimal position. The gain in the vertical and horizontal dimensions allowed an esthetic result with a single-tooth crown.

Arthroscopic autologous osteochondral grafting for cartilage defects of the knee: prospective study results at a minimum 7-year follow-up

BACKGROUND

Articular cartilage lesions, with their inherent limited healing potential, remain a challenging problem for orthopaedic surgeons. Various approaches have been proposed to treat these lesions; nevertheless, opinions on indications and clinical efficacy of these techniques are still controversial.

PURPOSE

To evaluate the outcome of osteochondral autografts for treatment of femoral condyle cartilage lesions at a medium-to long-term follow-up.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We prospectively evaluated 30 patients (mean age, 29.3 years) with full-thickness knee chondral lesions (<2.5 cm(2)) treated with arthroscopic autologous osteochondral transplantation. Thirteen patients underwent previous surgery, while 17 patients were operated on for the first time. In 19 patients, associated procedures were performed. All patients were evaluated at 2- and 7-year follow-up. The International Cartilage Repair Society form, Tegner score, and magnetic resonance imaging were used for clinical evaluation.

RESULTS

The International Cartilage Repair Society objective evaluation showed 76.7% of patients had good or excellent results at 7-year follow-up, and International Knee Documentation Committee subjective score significantly improved from preoperative (34.8) to 7-year follow-up (71.8). The Tegner evaluation showed a significant improvement after the surgery at 2- and 7-year follow-up (from 2.9 to 6.2 and 5.6, respectively); however, we noticed reduced sports activity from 2- to 7-year follow-up. Magnetic resonance imaging evaluation showed good integration of the graft in the host bone and complete maintenance of the grafted cartilage in more than 60% of cases.

CONCLUSION

The results of this technique at medium- to long-term follow-up are encouraging. This arthroscopic 1-step surgery appears to be a valid solution for treatment of small, grade III to IV cartilage defects.

Sinus floor elevation using autogenous bone or bone substitute combined with platelet-rich plasma

OBJECTIVE

Sinus augmentation is a common approach for patients with severe alveolar ridge atrophy. However, autogenous bone sometimes results in donor site complications. Bone substitutes with platelet-rich plasma (PRP) promote early bone formation with autogenous bone. Use of PRP on autogenous bone and a bovine bone substitute were investigated in this split-mouth animal study.

STUDY DESIGN

Premolars were extracted from minipigs. Each animal received sinus augmentation using a lateral approach with simultaneous insertion of 3 implants in each site. Groups were randomized using autogenous bone alone and combined with PRP or a bovine hydroxyapatite alone in combination with PRP.

RESULTS

Microradiographic findings in the autogenous group did not show significantly different rates by using autogenous bone alone or combined with PRP. Using the bovine hydroxyapatite as augmentation material only at 8 weeks, a nonsignificant effect in the PRP group could be seen. At all other observation periods, no significant influence was observed.

CONCLUSION

No significant influence of PRP was found.

Clinical and radiological results of non-cement impaction bone-graft method of total hip arthroplasty for rheumatoid arthritis

We performed total hip arthroplasty using the non-cement impaction auto-bone-grafting method with the resected femoral head for acetabular protrusion that is not combined with the destruction of acetabular rim or dysplasia of the hip joint. Ten patients (eight women and two men) with rheumatoid arthritis who showed acetabular protrusion underwent total hip arthroplasty using this method. All patients were able to walk with full weight within 5 days after surgery. The short-term results of our cases were very good. The postoperative periods of the radiographic-bone incorporation of the grafting bone were 2 months after surgery in four joints, 3 months after surgery in four joints, and 4 months after surgery in three joints. There were no cases that showed any migration or radiolucency around the acetabular component at the time of follow-up. Our operative technique is simple and easy, and it is a useful method for the treatment of protrusion in patients with rheumatoid arthritis.

Sequential changes in implanted cartilage after autologous osteochondral transplantation: postoperative acoustic properties up to 1 year in an in vivo rabbit model

PURPOSE

For successful autologous osteochondral transplantation, it is important that the cartilage in an implanted plug provide histologic replacement of damaged cartilage with cartilage that is structurally and mechanically normal. The purpose of this study was to investigate whether the press-fit technique reconstructs the normal hyaline cartilage and provides acoustic stiffness equal to that of normal intact cartilage.

METHODS

In 36 rabbits an osteochondral plug, 6 mm in diameter, was removed from the right patellar groove and grafted into a recipient hole, 5 mm in diameter, in the left patellar groove. Specimens at 2, 4, 8, 12, 24, and 52 weeks postoperatively were assessed by macroscopic and histologic observation and by use of an ultrasonic system. The ultrasonic acoustic stiffness, acoustic surface irregularity, and acoustic thickness of the implanted cartilage were examined and compared with normal intact cartilage.

RESULTS

The gross appearance of the implanted cartilage was glossy, maintained good surface smoothness, and survived well throughout the observation period. The cartilage recovered histologic features of hyaline cartilage. The acoustic stiffness decreased up to 12 weeks and then increased at 24 and 52 weeks after surgery. The acoustic stiffness at 8 or 12 weeks was significantly lower (acoustically softer) than that of control cartilage (P < .001). The acoustic stiffness at 52 weeks was equal to that of the control. The difference in acoustic surface irregularity was not significant. The acoustic thickness at 8 weeks was higher (acoustically thicker) than that of the control (P < .01).

CONCLUSIONS

Although the reason acoustically soft cartilage in plugs becomes acoustically stiff and whether the histology of the implanted cartilage had recovered completely remain unclear, the acoustic stiffness recovered to normal control values by 52 weeks postoperatively.

CLINICAL RELEVANCE

Postoperative care for up to 12 weeks should be taken after autologous osteochondral transplantation.

Clinical evaluation of demineralized bone allograft in a hyaluronic acid carrier for sinus lift augmentation in humans: a computed tomography and histomorphometric study

OBJECTIVES

Natural and synthetic graft materials are used routinely in sinus floor augmentations to help support implants in atrophic maxillary ridges. This clinical study was based on the hypothesis that the clinical effectiveness of demineralized freeze-dried bone allograft/demineralized bone matrix (DFDBA/DBM) in sinus lifts varies when used in combination bone graft substitute materials. To test this hypothesis, DFDBA was used together with one of three materials: in saline plus anorganic bone (DFDBA: Bio-Oss; in hyaluronic acid (DFDBA: HY, 32 : 68, w/w; DBX alone; DBX plus Bio-Oss; and DBX plus tricalcium phosphate granules (beta-TCP).

MATERIAL AND METHODS

Thirty-two sinus lift procedures, eight per group, were performed on 26 patients. Before surgery and at 8 months post-surgery when implants were placed, ridge heights were visualized by computed tomography (CT) and measured by morphometric analysis. Cores of bone were removed by trephine at the sites of implant placement; these biopsies from the graft sites were used for histomorphometric analysis.

RESULTS

All 32 sinus lift elevations were successful when measured by CT, increasing from an average 2.84+/-0.2 mm before treatment to 15.2+/-0.6 mm after treatment. The percent of each biopsy that was occupied by new bone and incorporated bone graft materials varied with each treatment: DFDBA+Bio-Oss, DBX+Bio-Oss, or DBX alone was higher than that for DBX+beta-TCP by approximately 10%. When comparing only newly formed bone, DBX+beta-TCP treatment resulted in 50% less bone than the other three preparations. All grafted sites received implants as per the treatment plan for each patient.

CONCLUSIONS

This study confirmed the hypothesis that new bone formation is dependent on the DFDBA formulation used and demonstrated that DBX, alone or in combination with other materials, can be used successfully for sinus floor elevation.

Evaluation of bone availability in the cleft area following secondary osteoplasty

INTRODUCTION

Osteoplasty in cleft patients provides a basis for shaping a closed dental arch. This study aimed at a radiological appraisal of transplantation success following secondary osteoplasty by means of alveolar bone height as related to some selected influencing factors.

MATERIAL AND METHODS

In this study, postoperative radiographs of 46 patients with unilateral or bilateral clefts of lip, alveolus and palate were analyzed retrospectively. Alveolar bone height was typed according to Abyholm and Bergland and evaluated in consideration of dentition at the time of surgery and existence of the lateral incisor.

RESULTS

In total, 76% (n = 35) successes (type I/II) were observed. 6 out of 46 patients (13%) had to be re-operated for osteoplasty at a later date. A non-significantly higher rate of successes occurred during the early mixed dentition. In patients with existing lateral incisor, a higher rate (78% vs. 68%) of alveolar bone heights type I/II was obtained.

CONCLUSION

The successful surgical outcome in terms of alveolar bone height is facilitated by treatment onset preferably during early mixed dentition and in presence of the lateral incisor. Although maximal success rates cannot be obtained using this method, the utility and effectiveness of secondary osteoplasty in cleft patients has been confirmed.

Early postoperative bone scintigraphy in the evaluation of microvascular bone grafts in head and neck reconstruction

BACKGROUND

Bone scintigraphy was performed to monitor anastomotic patency and bone viability.

METHODS

In this retrospective study, bone scans were carried out during the first three postoperative days in a series of 60 patients who underwent microvascular bone grafting for reconstruction of the mandible or maxilla.

RESULTS

In our series, early bone scans detected a compromised vascular supply to the bone with high accuracy (p < 10-6) and a sensitivity that was superior to the sensitivity of clinical monitoring (92% and 75% respectively).

CONCLUSION

When performing bone scintigraphy during the first three postoperative days, it not only helps to detect complications with high accuracy, as described in earlier studies, but it is also an additional reliable monitoring tool to decide whether or not microvascular revision surgery should be performed. Bone scans were especially useful in buried free flaps where early postoperative monitoring depended exclusively on scans. According to our experience, we recommend bone scans as soon as possible after surgery and immediately in cases suspicious of vascularized bone graft failure.

Pelvic reconstruction with a structural pelvic allograft after resection of a malignant bone tumor

BACKGROUND

Reconstruction of the pelvic arch after resection of a malignant pelvic tumor remains a major surgical challenge because of the high rate of associated complications. The purpose of this investigation was to assess the functional outcome and complication rate following treatment with a bone allograft to reconstruct the pelvis.

METHODS

Twenty-four consecutive patients underwent excision of a malignant pelvic bone tumor and reconstruction with a pelvic bone allograft. The living patients were followed for a minimum of twenty-four months. There were nineteen primary malignant bone tumors, sixteen of which were high-grade sarcomas, and there were five isolated metastases. Patients were examined clinically and radiographically and were assessed functionally with the Musculoskeletal Tumor Society score.

RESULTS

The mean age of the patients at the time of the index surgery was thirty-four years, and the mean duration of follow-up was forty-one months. Eighteen of the twenty-four resections involved the periacetabular area and were followed by reconstruction either with a hip prosthesis (thirteen) or with an osteochondral allograft alone (five). The six other resections involved the iliac bone. All patients received a massive bone allograft that had been sterilely procured without secondary irradiation. At the time of our last evaluation, eight patients were alive and free of disease. Seven patients had a local recurrence. Neurological deficits were present in six patients, and three had a deep infection. Nonunion of three of the sixteen allografts that could be evaluated was observed. Neither graft fracture nor lysis was observed. Eleven patients underwent surgical revision, with nine of these revisions related to the reconstruction. The average Musculoskeletal Tumor Society score at the time of the latest follow-up was 73% of the maximal possible score. The average score was 82% for the eleven patients with an age of less than twenty years at the time of the index procedure and 65% for the thirteen older patients. Ten patients walked without any assistive device, and five of them had normal function with no or only a slight limp.

CONCLUSIONS

Pelvic reconstruction after a limb-sparing resection is associated with a high risk of surgical complications and usually should be reserved for patients with a primary bone sarcoma. A pelvic allograft can restore the anatomy and provide good functional results, especially in young patients. Nonunion was the most common allograft-related complication.

[Assessment of bone grafting mineralization in patients with alveolar clefts using digital radiography]

INTRODUCTION

The objective of the work was to assess the suitability of digital radiography with the option of tomosynthesis for the purpose of mineralization of bone, grafted to the alveolar cleft fissure. Moreover the assessment of the influence of the patients age on the operation date on the transplanted bone mineralization degree was carried out. Furthermore, an attempt to compare the density of the transplanted bone to the density of the bone on the opposite side was taken on the basis of pantomographs. Additionally, the level of oral cavity hygiene and its influence on mineralization of the bone transplant were discussed.

MATERIAL AND METHODS

27 patients with complete cleft lip and palate, who underwent operation of autogenic bone graft to alveolar process were investigated. During clinical examination, information about the patients age on their operation date were collected, and DMF and OHI indicators were defined. Control digital intraoral X-rays of all patients aimed at the cleft area were taken. Additionally, conventional pantomographs of 18 patients for orthodontic indications were taken. Relative values of the grafted and healthy bones were defined on the basis of the intraoral and pantomographic images with the use of software Digora (Soredex).

RESULTS

The relative density of bone grafts, whose range was established by the means of the tomosynthesis option, and which was obtained through the analysis, was 87.8 and in the healthy bone (adjacent to transplant) - 149.2. The values of relative thickness of the transplanted and healthy bones were established on the basis ofpantomographs and proved to be lower than those obtained with the intraoral images. A statistical analysis of the intraoral images showed a substantial difference between the established values of the healthy and transplanted bones. In addition, the dependence between the degree of mineralization and the patients age on the day of the operation was observed. It was proven that the younger the patient was on that day, the higher the transplanted bone thickness was. Based on average values of DMF and OHI indicators, a high intensivity of caries was found in 78.3%, a good hygienic condition of the oral cavity in 78.3% and a satisfactory value in 21.7% of the cases.

CONCLUSIONS

1. Mineralization of the bone grafts to alveolar fissure, based on relative bone thickness obtained by use of an intraoral digital X-rays, differes significantly from the healthy bone. 2. Relative density of the bone grafts is highly dependent on the patient's age on the day of the operation: the younger the patient is, the better mineralization of the bones is. 3. Digital radiography with the option oftomosynthesis is very useful for establishing the scope of the bone grafts and, indirectly, for assessment of its mineralization. 4. Pantomography is not useful for assessment of density of bone grafts of cleft patients. 5. Cleft palate patients were found to have a good hygienic level and a high intensivity of caries. 6. A lowered relative thickness of bone grafts and a higher value of DMF indicator were observed in female patients.

A novel method to evaluate vertebral remodeling by radiography following anterior cervical decompression and interbody fixation with cylindrical cages: a contrast-comparing method using "Scion image"

In an attempt to study bone remodeling by noninvasive methods, spinal bone radiodensity was assessed in five patients treated with anterior cervical decompression and fusion (ACDF) using cylindrical titanium cages. Plain radiographs were used to study specific areas of vertebral bone interposed in two-level cages with the two cephalad vertebrae for controls. Measurements were made immediately after surgery and 1, 3, 6, 12 and 18 months postoperatively. The data were analyzed quantitatively with a contrast-comparing method (CCM) using "Scion image". There were two cyclical changes in vertebral remodeling. First, in all patients there were gradual increases in bone density at the ventral part compared to the dorsal part of the vertebral body for up to 12 months; then the density decreased at 18 months. Second, a linear gradient in radiodensity from the ventral part to the dorsal part of the vertebral body observed immediately following spinal fusion gradually disappeared by 12 months; nonhomogeneous distributions of trabecular bone were appeared. Then, the linear gradient in density appeared again at 18 months. This investigation helps elucidate the radiographic evidence for the remodeling of vertebral bone in patients treated with ACDF.

[Computed tomography assessment of incorporation bone grafts after cemented acetabular revision]

The aim of the study was assessment, on the basis of computed tomography (CT) examination, of remodelling of compacted frozen bone sliver grafts used in acetabular revision arthroplasty.

MATERIAL AND METHOD

The study involved ten patients treated in the years 1998-2000 for aseptic loosening of hip joint prosthesis elements. Eight women and two men were studied. The mean age of the patients was 69.6 years (from 52 to 74 years). The mean time between primary and revision arthroplasty was 6.8 years. Spiral CT examination was performed 6 weeks and 3, 6, 12, 24, 36 months after the operation. Density measurement was done using ROI (region of interest) function including spongy bone area from 50 to 80 mm2. The studied layer thickness was 3.2 mm. In the examination both hip joints were assessed, accepting the joint not operated on as standard for a given patient. The measurement was done in six zones according to DeLee, Charnley.

RESULTS

Progressing reduction of graft density was found in relation to healthy bone density. During the first three months most rapid density reduction was observed in all patients. The lowest density decrease was seen in the postero-superior part of the acetabulum while the highest density reduction occurred in the lower part. Trabeculation change was observed from that resembling compact bony tissue to that corresponding to spongy tissue. In two patients after six months a significant graft density reduction occurred both in the lower and upper parts of the acetabulum. In these patients acetabular loosening was confirmed, requiring reoperation.

CONCLUSIONS

CT examination of bone density makes possible quantitative assessment of bone graft remodelling and qualitative assessment imaging the structure of the grafts. The non-invasive method of CT examination of bone graft density allows for prognostication as to stability of the seated acetabulum.

Changes of mineralization of free autogenous bone grafts used for sinus floor elevation

For augmentations before implant placement in areas of minor bone quantity, autogenous bone is considered the reference to all bone substitutes used alternatively. Autogenous bone transplants originate from various donor areas and can be prepared in different ways before augmentation. They may either be used as block grafts or may be milled to granules that can be used solitarily or in combination with a bone substitute. In a prospective study, 61 patients of the Maxillofacial Surgery Department of our University receiving two-stage sinus floor elevation because of insufficient bone supply were randomly selected. At first-stage surgery, the local augmentation procedure, monocortical probes were obtained on the site of bone harvesting. At second-stage surgery, the implant insertion 6 months after the elevation procedure, bone cores were harvested in the areas of implant placement. Donor regions were the following three areas: the posterior (N=28) and anterior pelvic region (N=15) and the chin region (N=18). The implanted bone in all three groups was particulated to granules of 2-3 mm(2) using a bone mill. All biopsies were analyzed by means of microradiography. The anterior pelvic bone grafts showed a mineralized tissue grade of 35.1+/-7.6% before milling and augmentation. The posterior pelvic bone grafts exhibited a mineralization of 30.7+/-9.5% and the chin bone grafts 74.6+/-8.6%. At second-stage surgery after 6 months, the mineralization was 36.1+/-7.59% in the areas where bone grafts from the anterior pelvic crest were used. Probes harvested from sites with posterior pelvic bone augmentations showed a mineralization rate of 34.5+/-6.5%, and sites were chin bone grafts were applied expressed a mineralization of 54+/-8.6% (P=0.003 compared with the pre-operative value). The comparison of the microradiographical results demonstrated significant differences in the mineralization grades depending on the origin of the graft. The origin of the grafts and their remodeling influenced the mineralization rates found at 6 months. How these data may influence the long-term clinical outcome considering implant survival and bone resorption has to be examined in further long-term studies.

Imaging characteristics of bone graft materials

Bone graft materials are widely used in reconstructive orthopedic procedures to promote new bone formation and bone healing, provide a substrate and scaffolding for development of bone structure, and function as a means for direct antibiotic delivery. Bone graft materials include autografts, allografts, and synthetic substitutes. An autograft (from the patient's own bone) supplies both bone volume and osteogenic cells capable of new bone formation. The imaging appearance of an autograft depends on its type, composition, and age. Autografts often appear as osseous fragments at radiography. At computed tomography (CT), autografts appear similar to the adjacent cortical bone. At magnetic resonance (MR) imaging, however, autografts have a variable appearance as a consequence of the viable marrow inside them, a feature not present in other graft materials. An allograft (from cadaveric bone) has an appearance similar to that of cortical bone on radiographs and CT images. An allograft in the form of bone chips or morsels does not show those features on radiographs and CT images, but instead appears as a conglomerate with medium to high opacity and attenuation within the bone defect. In the immediate postoperative period, allografts appear hypointense on both T1- and T2-weighted MR images. Hematopoietic tissue replaces the normal fatty marrow in the later phases of graft incorporation. Synthetic bone substitutes are much more variable in imaging appearance. As the use of bone allografts and synthetic substitutes increases, familiarity with postoperative imaging features is essential for differentiation between grafts and residual or recurrent disease.

[Study of biomechanical effects on the reconstruction of mandible defect with autogenous bone grafts]

The biomechanical effects of the reconstructed mandible with autogenous bone grafts were analyzed and evaluated, under simulated mechanical environment of occlusion. Based on anatomical feature of the human skeleton, muscle system and the clinical B, BS"S" and RB"S"defect patterns, the modularized model of mandible and the three finite element models of the fibula grafts and iliac crest grafts reconstruction mandible were made. The stress state calculations under bite force were also processed. The findings are as follows: Along the right connection area to left connection area (corresponding to far-end of the molar teeth alveolar ridge and the chin section respectively), the stress state on the various grafted bone all changes from compression stress to tensile stress. There is obvious change on the stress distribution between the fibula type reconstruction mandible and normal one. The stress on the grafted bone which is mainly made up of cortical bone is approximately 5 times higher than that of normal, which indicates the obvious stress shielding effect; the stress distribution of the iliac crest type reconstruction mandible is close to the normal mandible, the iliac crest used is mainly made up of cancellous. Therefore, the mechanical properties of the reconstructed mandible with iliac crest are more similar to normal mandible, which is beneficial to wound healing and further functional reconstruction.

Three-dimensional finite-element analysis investigating the biomechanical effects of human mandibular reconstruction with autogenous bone grafts

PURPOSE

To investigate the biomechanics of the mandible following reconstruction with autogenous bone grafts.

MATERIAL

Computerized tomography scan images of a human mandible, fibula and iliac crest were collected and used to build models on a PC.

METHODS

Four finite-element analysis (FEA) models of mandibles reconstructed with autogenous bone were created. The principal stresses of marked points, the Von Mises stresses at anatomical index regions, and the force values of temporo-mandibular joints and masticatory muscles were calculated.

RESULTS

Compared with the normal mandible, the one repaired with a fibula had greater Von Mises stresses on the grafted bone; the one repaired with iliac crest bone had the similar distribution of the Von Mises stresses as in the normal mandible. The principal stresses in the autograft varied between tensile and compressive stresses from the right graft/bone binding interface to the left in all reconstructed mandibles. On the whole, the maximum Von Mises stress was greater on the mandible reconstructed with fibula than that reconstructed with iliac crest.

CONCLUSION

Mandibles repaired with iliac crest grafts have more mechanical properties similar to normal than those repaired with fibula grafts.

Effects of platelet-rich plasma on the healing of autologous bone grafted mandibular defects in dogs

PURPOSE

This study was undertaken to describe both radiographically and with histomorphometric analysis the effect platelet-rich plasma (PRP) has on immediate autologous bone grafts in a dog model.

MATERIALS AND METHODS

Thirteen dogs comprised the study. Twelve adult dogs received bilateral inferior mandibular border defect resections measuring 2 cm x 1 cm. The right defect was immediately grafted with milled autologous iliac corticocancellous bone along with 2 cc of PRP that was developed in a standardized fashion. The left side was immediately grafted with the same amount of autologous iliac corticocancellous bone placed without PRP. Three animals were sacrificed at 1, 2, 3, and 6 months. A thirteenth dog underwent bilateral inferior border resections with only PRP placed in the right defect, and nothing placed in the left defect. This dog was sacrificed at 6 months. Ten and 3 days before sacrifice all animals received 10 mg/kg body weight tetracycline intravenously. At sacrifice, grafts along with adjacent native bone were harvested, fixed, radiographed, and processed for epifluorescence analysis.

RESULTS

Analysis of digitized radiographs indicated that at 1 and 2 months the non-PRP grafts were significantly more dense than the PRP grafts, and at 3 and 6 months there was no significant difference. Histomorphometric analysis showed that at 1 and 2 months there was significantly less grafted bone and more new bone in the PRP grafts than in the non-PRP grafts. At 3 and 6 months there was no difference in the amount of grafted bone or new bone between the PRP and non-PRP grafts. Histology of the control dog showed incomplete bony healing at 6 months, suggesting that this was a critical sized defect. The bone apposition rate for all times in the PRP and non-PRP graft sites did not significantly change.

CONCLUSION

PRP appeared to enhance early autologous graft healing. However, after 2 months this effect is no longer significant. The early enhanced healing occurred by increasing the amount of non-viable grafted bone that was removed and increasing the amount of new bone that was formed. PRP did not change the rate at which new bone was formed, and no increase in trabecular density was realized in these grafts.

Evaluation of bone volume following bone grafting in patients with unilateral clefts of lip, alveolus and palate using a CT-guided three-dimensional navigation system

PURPOSE

In cleft patients the eruption of the permanent canine depends very much on the amount of bone available following bone grafting. The purpose of this study was to evaluate the initial defect in alveolar clefts and the volume of bone bridging found in unilateral clefts which had undergone bone grafting.

PATIENTS AND METHODS

To determine the fate of the bone graft in cleft palate patients a three-dimensional CT-based Navigation System (Zeiss, Aalen, Germany) was used. CT scans of 16 patients with unilateral clefts were taken immediately preoperatively and 1 year postoperatively. The patients underwent surgery between the age of 9 and 14 years using iliac crest bone grafts. The data was transferred to the work station of the navigation system. Using the STN software, the defect at the alveolar clefts and volume of the bone grafts were determined in each case. Three-dimensional models were created showing the amount of bone immediately preoperatively and 1 year postoperatively.

RESULTS

The size of the cleft defect did not correlate with the success rate of the alveolar bone grafting. The form of the transplant remained almost constant when the permanent canine erupted spontaneously into the graft. In cases of absence of the permanent tooth or when the permanent canine required orthodontic treatment, significant bone loss could be observed in the buccopalatal direction.

CONCLUSION

Three-dimensional reconstruction of bone grafts using a navigation system enables a valuable objective assessment of graft volume. Bone formation can be assessed in all three dimensions showing a high grade of resorption in patients lacking physiological load.

Sinus graft with biogran, autogenous bone, and PRP: a report of three cases with histology and micro-CT

Three sinuses were grafted with a bioactive glass bone substitute (Biogran) mixed with autogenous bone retrieved from intraoral donor sites. In two of the three sinuses a platelet-rich plasma (PRP) gel was added to the graft. Bone biopsies retrieved after 5, 6, and 15 months were analyzed. Micro-computerized tomography (micro-CT) values of total bone volume/total volume (TBV/TV) were very reliable compared to histomorphometry. Biogran mixed with autogenous bone and PRP seems to have a positive effect in sinus grafting, with TBV/TV values ranging between 40% and 68%. Micro-CT results have never been compared with histomorphometry for the evaluation of grafted biomaterials. Micro-CT evaluation of some morphometric parameters was difficult, because the radiodensities of Biogran and a certain grade of bone mineralization were similar.

Alveolar bone grafting: achieving the organisational standards determined by CSAG, a baseline audit at the Birmingham Children's Hospital

INTRODUCTION

Birmingham Children's Hospital (BCH) is the centre for a regional comprehensive cleft service attempting to implement the national guidelines for minimum standards of care. A national audit of cleft management (CSAG) found that 58% of alveolar bone grafts were successful; published series suggest that success rates can be of the order of 95%. We present the results of an audit of alveolar bone grafting over a 33-month period, after implementation.

PATIENTS AND METHODS

A retrospective clinical process audit was taken from the hospital notes and an analysis of radiological outcome by Bergland score was obtained by two independent assessors.

RESULTS

The audit highlighted the difficulties of integrating the increased clinical workload. Other difficulties included poorly standardised pre- and postoperative occlusal radiography, inconsistent orthodontic management and a lack of prospective data collection. An 81% success rate for alveolar bone grafting compares favourably to the CSAG study. Of 82 patients, 68 had sufficient data for a retrospective review; 21 were our own patients and 47 were referred into the centralised service. The success of bone grafting as defined by CSAG (including Bergland scores) is based on only two-thirds of the patients as many have their orthodontic treatment managed in more distant units and radiographs are much harder to obtain. Bone grafting later than age 11 years, was true for 28% (6/21) of our BCH patients and 46% (22/47) for those referred to our service.

CONCLUSIONS

This audit demonstrates what has been achieved in a re-organised service in the context of Real Politik in the NHS and suggests the areas that require improvement.

[The results of primary total knee arthroplasty with bone stock restoration by autologous grafts from resected bony ends]

AIM OF THE STUDY

The aim of the study is the comparison of results of primary total knee arthroplasty with large bone stock deficiencies treated with autologous bone grafts from resected joint ends (both solid and morselized) with the group of patients in whom knee arthroplasty was made without the need of bone grafting.

MATERIAL AND METHOD

342 primary total knee replacements implanted till the end of 2004 at Orthopaedic and Traumatology Department in Lublin were examined. Bone stock defects were treated in 37 knees (35 patients). The necessity of reconstruction resulted from destruction of knee joint surfaces in advanced degenerative osteoarthritic processes or rheumatic disease. Autologous solid bone grafting was used in 22 knees, morselized in 13, meanwhile 2 different required both types of grafts. The medial tibial condyle bone stock defects were the most frequent--26 knees. Control group consists of 39 knees in 33 patients treated in the same period without the need for bone grafting and prostheses were implanted directly on resected surfaces. Preoperative and postoperative knee function was established with Hospital for Special Surgery Score (HSS). The X-rays were analyzed with the special regard for: correctness of implants placing, presence of radiolucence zones both around implants and grafts, and bone grafts healing.

RESULTS

The analysis of subsequent X-rays showed bone grafts healing (both solid and morselized) in 21 knees. In 4 knees progressive bone grafts lysis was observed. The remaining knees showed the presence of grafts and lack of evidence of healing in surrounding host bone. No differences were observed in number of intra- and postoperative complications, radiographic knee replacements geometry and long-term clinical results in both groups of patients.

CONCLUSIONS

1) Results of total knee replacements with autologous bone grafting for bone stock reconstruction are comparable with the results of TKR without the need for bone grafting. 2) Natural harvesting of the graft material from resected joint ends and effectiveness of reconstruction increase the value of the method. 3) The durability of early good results need further examination.

Effect of recombinant human bone morphogenetic protein-2 in an experimental model of spinal fusion in a radiated area

STUDY DESIGN

An animal model of posterolateral intertransverse process spine fusion was used.

OBJECTIVES

To investigate whether recombinant human bone morphogenetic protein-2 (rhBMP-2) can overcome the adverse effects of radiation treatment (RT) on spine fusion.

SUMMARY OF BACKGROUND DATA

Spinal metastases are common. Some of these patients are candidates for spinal cord decompression and vertebral reconstruction; however, radiation has significant adverse effects on bone healing.

METHODS

A posterolateral fusion model was used with rhBMP-2 or iliac crest bone graft (ICBG). Eighty one-year-old rabbits were divided into eight groups: 1) RT 14 days before surgery, rhBMP-2; 2) RT 14 days before surgery, ICBG; 3) RT 2 days after surgery, rhBMP-2; 4) RT 2 days after surgery, ICBG; 5) RT 14 days after surgery, rhBMP-2; 6) RT 14 days after surgery, ICBG; 7) no RT, rhBMP-2; 8) no RT, ICBG. Animals were killed approximately 35 days after surgery. Manual palpation was the definitive test of fusion. Biomechanical and histologic assessments were also performed.

RESULTS

All rhBMP-2 groups had significantly greater fusion rates versus respective ICBG control groups: 1 (86%) versus 2 (0%) (P = 0.005), 3 (100%) versus 4 (0%) (P < 0.0001), 5 (100%) versus 6 (0%) (P < 0.0001), and 7 (100%) versus 8 (60%) (P = 0.003). Stiffness and ultimate strength did not differ significantly between the experimental and control groups. Histologic assessment confirmed new bone formation in the fusion masses from rhBMP-2 groups.

CONCLUSIONS

Use of rhBMP-2 produced a significantly greater rate of fusion compared with ICBG in a previously radiated area in an animal model, without the morbidity of ICBG harvesting and without the risk of inadvertently using autograft contaminated by micrometastases.

Long-term radiographic assessment of secondary alveolar bone grafting outcomes in patients with alveolar clefts

OBJECTIVE

The objective of this study was to assess the outcomes of secondary alveolar bone grafting (SABG) in patients with complete, unilateral cleft lip and palate (UCLP) operated on before eruption of the permanent canine.

STUDY DESIGN

Sixty-five periapical radiographs from 41 patients with left UCLP and 24 with right UCLP (9 to 12 years old at SABG), were analyzed retrospectively for the amount of bone in the cleft site according to the Bergland and Chelsea scales, and for the occurrence of canine eruption (CE) through the neoformed bone.

RESULTS

Of the cases, 71% were classified as Bergland type I and Chelsea type A; 15% as types II/C, and 14% could not be classified. CE was observed in 95% of the cases operated on 4 years before the study.

CONCLUSIONS

SABG performed before CE is a procedure with a high rate of success. The radiographic scales proved to be important instruments for assessing surgical outcomes.

Postoperative Tomographic Assessment of Veneer Bone Grafting with Implant Placement in the Maxillary Anterior Region

Various ridge augmentation and sinus lift procedures were performed in severely resorbed alveolar crests of a maxilla to provide some volume for implant treatment. It was reported that the outcome of maxillary sinus lift procedures was evaluated with conventional tomography or computerized tomography, and that grafted bone around implants markedly progressed in resorption, particularly at the implant apex. However, veneer bone grafting with implant placement has not been evaluated after treatment with imaging techniques. Therefore, the purpose of this study was to assess veneer bone grafting after maxillary anterior implant treatment. Seven patients with a mean age of 24 years, with implants placed in the maxillary anterior region with or without autogenous veneer bone grafting were postoperatively examined using conventional tomography. On tomograms, the ratio of bone-to-implant contact and the area of bone were measured in labial bones with bone grafts, and they were compared with the values without bone grafts. In cases with bone grafting, the average ratio of bone-to-implant contact was 63.6%, whereas 81.8% was formed in cases without bone grafting. The average area of bone was 12.9 mm and 23.4 mm in patients with and without bone grafting, respectively. No significant difference was found between the implants with and without bone grafts. Resorbed labial bone was observed in the maxillary anterior region with and without veneer bone grafting.

The evaluation of processed cancellous bovine bone as a bone graft substitute

OBJECTIVE

To determine the ability of a novel bovine cancellous bone xenoimplant to act as an osteoconductive graft in an ovine femoral defect model. An autograft harvested from the xenoimplant site was placed in a contralateral limb defect for comparison.

MATERIAL AND METHODS

The xenoimplant used had been rendered immunologically inert by a novel defatting and deproteinating process. Following surgical implantation of cores into condylar cancellous bone defects, fluorochrome labels were administered to 12 sheep at 2 1/2, 4 1/2 and 8 weeks. Incorporation of the xenoimplants and autografts into the host bone was compared radiographically and histomorphometrically at 10 weeks.

RESULTS

Radiographically, the degree of osteointegration was comparable. Histomorphometric data, consisting of labelled surface (LS) estimates, confirmed osteoconductive properties of both the xenoimplants and autografts. Remodelling activity was greatest in the xenoimplants at 2 1/2, weeks. At 4 1/2 weeks, there was more activity in the autograft, but by 8 weeks they were performing similarly. Xenoimplant-LS estimates were comparable or greater than those of the autograft at all times.

CONCLUSIONS

Processed bovine cancellous bone xenoimplants were osteoconductive in this model and show promise for development as a biomaterial in human and veterinary orthopaedic surgery.

Bone Grafting Procedures for Osseous Defects Associated with Dental Implants

The purpose of this study was to clinically and radiographically evaluate the use of bone grafting therapy for treatment of osseous defects before implant surgery. After bone graft reconstruction, implants may be placed in previous areas of osseous defect with the expectation of long-term positive results.

Surgical Success of Intraoral Autogenous Block Onlay Bone Grafting for Alveolar Ridge Augmentation

This article evaluates the surgical success of alveolar bone augmentation using intraoral block bone graft prior to dental implantation and measures the amount of bone accumulation using this technique. A consecutive retrospective study was conducted on patients who had onlay bone grafts from 1999 to 2001. Files of 56 healthy patients reporting 64 bone graft operations were reviewed. Medical history, smoking status, area of surgery, bone origin (donor sites) and complications were recorded. Panoramic and tomographic radiographs were measured for the vertical and horizontal bone addition and mesiodistal dimension of the graft. Graft exposure or/and graft removal were defined as failure; hematoma, swelling, inflammation, or temporary paresthesia were defined as complications. The average vertical addition was 5.6 mm measured from the bottom of the vertical lesion before bone grafting to the top of the graft. The average faciolingual addition was 3.8 mm. The mesiodistal graft length ranged from 4 mm to 67 mm (average 15.2 mm). According to our criteria, 56 (87.5%) of the 64 bone grafts were successful, 46 (71.9%) were totally uneventful, and 10 (15.6%) had complications. Smoking and diabetes were associated with a high rate of complications and graft failure. More complications were observed in the vertical than in the horizontal bone grafts. Intraoral bone block graft is a predictable operation with high success rates that provides faciolingual and vertical bone addition. Onlay bone grafting has a low rate of complications and failures. Intraoral bone graft should not be recommended for diabetic patients and smokers.

Application of limited cone beam computed tomography to clinical assessment of alveolar bone grafting: a preliminary report

OBJECTIVES

The aim of this study was to demonstrate the clinical applicability of limited cone beam computed tomography (Dental 3D-CT) for assessment of bone-grafted alveolar cleft.

PATIENTS AND METHODS

Seventeen bone bridges were examined after alveolar bone grafting in 13 patients with cleft lip and palate. All bone bridges, including cleft-adjacent teeth, were examined by plain radiography and the Dental 3D-CT imaging system.

RESULTS

The plain radiographs showed the approximate condition of the bone bridge and cleft-adjacent teeth. The Dental 3D-CT images clearly showed precise three-dimensional (3D) morphology of the bone bridge, 3D relationships between the bone bridge and the roots of cleft-adjacent teeth, and their periodontal condition. In addition, the conditions surrounding dental implants installed in the bone bridge could be observed three-dimensionally.

CONCLUSIONS

The results indicate that the Dental 3D-CT imaging system is suitable for clinical assessment of alveolar bone grafting before and after installation of dental implants or orthodontic treatment of the cleft-adjacent teeth.

A prospective multicenter randomized clinical trial of autogenous bone versus beta-tricalcium phosphate graft alone for bilateral sinus elevation: histologic and histomorphometric evaluation

PURPOSE

Two different graft materials, beta-tricalcium phosphate (Cerasorb) and autogenous bone, were used in the same patient. The objective was to determine whether donor site morbidity could be avoided by using pure-phase beta-tricalcium phosphate (Cerasorb).

MATERIALS AND METHODS

Bilateral sinus grafting was performed on 20 selected patients; Cerasorb was used on the experimental side, and autogenous bone was used on the control side. In each patient, one side was randomly designated the experimental side. In 10 of the 20 patients, the maxilla reconstruction included sinus grafting and onlay bone grafting. Implants were placed 6 months after the procedure. In addition to routine panoramic radiographs, in 10 of the 20 patients, 2- and 3-dimensional computerized tomographic examinations were performed pre- and postoperatively and after implantation. Eighty bone biopsy specimens were taken at the time of implant placement.

RESULTS

Histologically and histomorphometrically, there was no significant difference between the experimental and control grafts in terms of the quantity and rate of ossification. For each histologic sample, the total surface area, the surface area that consisted of bone, and the surface area that consisted of graft material were measured in mm2, and bone and graft material were analyzed as percentages of the total. The mean percentage bone areas were 36.47% +/- 6.9% and 38.34% +/- 7.4%, respectively; the difference was not significant (P = .25).

DISCUSSION AND CONCLUSION

Comparisons with other studies reveal that beta-tricalcium phosphate (Cerasorb) is a satisfactory graft material, even without autogenous bone.

Maxillary sinus floor augmentation using a beta-tricalcium phosphate (Cerasorb) alone compared to autogenous bone grafts

PURPOSE

A prospective human clinical study was conducted to determine the clinical and histologic bone formation ability of 2 graft materials, a beta-tricalcium phosphate (Cerasorb; Curasan, Kleinostheim, Germany) and autogenous chin bone, in maxillary sinus floor elevation surgery.

MATERIALS AND METHODS

Ten healthy patients underwent a bilateral (n = 6) or unilateral (n = 4) maxillary sinus floor elevation procedure under local anesthesia. In each case, residual posterior maxillary bone height was between 4 and 8 mm. In cases of bilateral sinus floor elevation, the original bone was augmented with a split-mouth design with 100% beta-tricalcium phosphate on the test side and 100% chin bone on the contralateral control side. The unilateral cases were augmented with 100% beta-tricalcium phosphate. After a healing period of 6 months, ITI full body screw-type implants (Straumann, Waldenburg, Switzerland) were placed. At the time of implant surgery, biopsy samples were removed with a 3.5-mm trephine drill.

RESULTS

Sixteen sinus floor elevations were performed. Forty-one implants were placed, 26 on the test side and 15 on the control side. The clinical characteristics at the time of implantation differed, especially regarding clinical appearance and drilling resistance. The increase in height was examined radiographically prior to implantation and was found to be sufficient in all cases. After a mean of nearly 1 year of follow-up, no implant losses or failures had occurred.

DISCUSSION

The promising clinical results of the present study and the lack of implant failures are probably mainly the result of requiring an original bone height of at least 4 mm at the implant location.

CONCLUSION

Although autogenous bone grafting is still the gold standard, according to the clinical results, the preimplantation sinus floor elevation procedure used, which involved a limited volume of beta-tricalcium phosphate, appeared to be a clinically reliable procedure in this patient population.

The use of hydroxyapatite and autogenous cancellous bone grafts to repair bone defects in rats

Bone grafts are frequently used in the treatment of bone defects. Bone harvesting can cause postoperative complications and sometimes does not provide a sufficient quantity of bone. Therefore, synthetic biomaterials have been investigated as an alternative to autogenous bone grafts. The objective of this study was to evaluate the repair of bone defects by autogenous cancellous bone grafts or porous bioceramic discs of hydroxyapatite/phosphate cement mixture. Two 5-mm diameter defects were made in the skulls of rats and filled with the bioceramic material or cancellous bone. The rats were sacrificed 2, 4, 8 and 24 weeks after surgery and tissue samples were analyzed by radiography and histology. By the 24th week, the defects filled with autogenous cancellous bone grafts or bioceramic material showed similar volumes of bone tissue within the defect. However, defects treated with bioceramic material were almost completely closed as a result of the joining of ceramic fragments and the neoformed bone tissue, while those filled with autogenous grafts showed several areas filled with connective tissue. These results indicated that the osteointegration of bioceramic fragments allowed the reconstruction of parietal bone defects without the need for a bone graft.

Radiographic Analysis of the Transcrestal Sinus Floor Elevation: Short-Term Observations

BACKGROUND

There are some limitations for implant placement in the posterior maxilla when there is an extended sinus. Various techniques for sinus floor elevation allow an increase in implant length.

PURPOSE

The aim of the present radiographic study was to assess the augmented site in the sinus around implants that were installed by means of an osteotome-mediated transcrestal sinus floor elevation.

MATERIALS AND METHODS

Thirty-three patients with 44 implants were available. In 39% of the implants the sinus floor elevation was performed exclusively with bone chips. Bone fill material (Bio-Oss, Geistlich Söhne AG, Wolhusen, Switzerland) was additionally used to increase the volume and stability of the lifted area at 61% of the implants. The visibility and morphology of the augmentation were assessed and compared by means of intraoral radiography (long-cone technique).

RESULTS

All implants were stable and were considered to be successful when they were reexamined in the context of the present study. The mean residual bone height was 5.78 +/- 1.4 mm. The increase of the implant length as compared to the original bone height resulted in a mean value of 3.87 +/- 2.0 mm. The volume and density of the lifted area were more visible if Bio-Oss was added. A shrinkage and/or condensation of the grafted material was visible at 37% of the implants after a minimum loaded period of 200 days. Equally, a decreased visibility of the original sinus floor was noted at 61% of implants. The formation of a cortical bone layer at the apex of the implants was detected at 35% of implants.

CONCLUSIONS

The surgical procedure appears to be a safe method with rare complications. Radiographic assessment of the augmentation procedure proved to be difficult, and measurements are not fully reliable.

Maxillary Sinus Augmentation with Platelet-Rich Plasma and Fibrinogen Cryoprecipitate: A Tomographic Pilot Study

The purpose of this study was to evaluate the clinical efficacy of platelet-rich plasma, autologous bone, and autologous fibrinogen as cryoprecipitate in maxillary sinus augmentation procedures. Six patients (age range, 29-58) undergoing sinus augmentation procedures were included in the study. Platelet-rich plasma and autologous fibrinogen in the form of cryoprecipitate were prepared from 300 ml of blood. Sinus augmentation was performed with intraoral bone grafts, platelet-rich plasma, and cryoprecipitate. The amount of regeneration was then evaluated quantitatively and qualitatively with Spiral TC (Dentascan) pre- and postoperatively 6 months after the intervention. Orthopantomography was performed preoperatively 3 and 6 months after the surgery. A mean platelet concentration of 320.5% was obtained from the baseline platelet blood count. The tomographic analysis indicated an average bone augmentation of 6.27 mm (range, 3.5-10 mm). Radiologically, a satisfactory morphological recovery of the maxillary jaw was obtained. No graft resorption was noticed. Orthopantomography indicated mineralization as early as 3 months postoperatively in the entire study population. This technique appeared to be safe and effective. Our preliminary results encourage the clinical use of platelet-rich plasma associated with cryoprecipitate.

Beta-tricalcium phosphate (beta-TCP) graft combined with bone marrow stromal cells (MSCs) for posterolateral spine fusion

Macaque lumber posterolateral spine fusion (PLF) was performed by using beta-TCP graft combined with bone marrow derived stromal cells (MSCs), to evaluate whether a beta-TCP/MSCs hybrid can be used for PLF instead of autogenous bone graft. Nine crab-eating macaque underwent bilateral PLF at L4-L5. The implants were divided into three groups: 1) beta-TCP/MSCs hybrid, 2) autogenous bone, and 3) beta-TCP. Six monkeys were sacrified at 12 weeks and three monkeys were sacrificed at 24 weeks after implantation. Manual palpation, radiography, micro computed tomography, peripheral quantitative computed tomography (pQCT), and histology were used to assess bone formation. Manual palpation and X-ray showed that 83.3% of hybrid groups and 66.7% of autogenous groups achieved solid spine fusion, whereas none of other groups fused. Histological analysis showed that all of the hybrid groups achieved massive bone formation. Bone mineral density (BMD) evaluated with pQCT in the hybrid groups increased by additional new bone. Beta-TCP/MSCs hybrid can be used for PLF instead of autogenous bone graft. Thus it can be hypothesized that the monkey PLF can simulate human PLF.

Reconstruction of maxillary and mandibular defects using prefabricated microvascular fibular grafts and osseointegrated dental implants - a prospective study

The fibular flap can be used for a variety of indications. Recently, the treatment of four patients with severely atrophied upper jaws using a method to prefabricate the vascularized fibular graft has been published. This technique consists of a two-stage operation procedure that allows simultaneous prosthodontic rehabilitation and immediate placement of dental implants. In this paper eight patients with 29 ITI implants (Straumann AG, Waldenburg, Switzerland) who had reconstruction of either the upper or lower jaw are presented. The aim of the study was (i) to evaluate the behavior of the newly formed soft tissue around implants inserted in the fibula by applying periodontal parameters, (ii) to monitor prospectively the integration of the implants in the fibular graft, and (iii) to assess the osseous integration of the fibular graft used for reconstruction of the upper or lower jaw. Two implants failed during the observation time because of avascular bone at the distal end of the fibular graft. Stabilization of the graft, however, was never compromised. Due to the prefabrication firmly attached gingiva-like soft tissue could be provided preventing periimplant soft tissue inflammation and facilitating oral hygiene. After 1 year of observation the mean attachment level was similar to implants placed in original bone whereas vertical bone loss measured radiographically was lower in the present study. This may indicate that the remodeling of a bicortical bone requires a longer period of time compared with the bone of the alveolar crest. The prospective 1-year results are promising but long-term evaluation of periodontal and radiological parameters are required.

Guided tissue regeneration in intrabony periodontal defects following treatment with two bioabsorbable membranes in combination with bovine bone mineral graft. A clinical and radiographic study

AIM

Comparison of two bioabsorbable barriers (collagen and polylactic acid (PLA) membranes) combined with a bovine bone mineral (BBM) graft, with an access flap procedure (AFP) alone for treating intrabony defects.

MATERIAL AND METHODS

Thirty-four subjects participated in this prospective, controlled clinical trial. Baseline clinical examination (probing depth (PD), clinical attachment level (CAL)) of selected sites was performed 2 months after completion of conservative treatment in conjunction with hard-tissue measurements to ascertain the depth of the defect (cementoenamel junction to the bottom of the defects). After randomly dividing patients into three groups (two membrane groups, one control group), full thickness flaps were elevated and exposed root surfaces planed before filling defects with bone graft and positioning a barrier membrane covering the defect. The control group was treated identically except for the barrier and bone graft placement. Clinical treatment outcomes were finally evaluated 12 months after surgery for changes of PD and CAL. Radiographs at baseline and 12 months were compared using non-standardized digital radiography.

RESULTS

A mean reduction in PD value of 5.08 mm and mean CAL gain of 4.39 mm occurred in the collagen-BBM group. Corresponding values for the PLA-BBM group were 4.72 and 3.71 mm, while access flap procedure (AFP) sites produced values of 2.50 and 2.43 mm. All improvements in clinical parameters were statistically significant (p<0.001) within groups for all variables. Both membranes produced statistically greater PD reduction and CAL gain compared with AFP treatment (p<0.05). Comparison between barrier groups failed to reveal any statistically significant difference in probing pocket depth reduction (p=0.56) or in CAL gain (p=0.34).

CONCLUSION

Placement of the two barrier membranes used in the present study in combination with BBM graft significantly improved clinical and radiographic parameters of deep intrabony pockets and proved superior to access flap alone.

Atrophic mandible reconstruction using calvarial bone grafts and implant-supported overdentures: radiographic assessment of autograft healing and adaptation

Bone grafting constitutes a vital surgical procedure in the management of severely atrophic mandibles. In this regard, calvarial bone autografts are applied in the reconstruction of wide mandibular defects caused by edentulousness and long-term denture-related resorption. Grafts are used as a framework to augment the residual ridge and provide implant stability for further prosthetic restoration. On the basis that radiographic evidence corresponds to biologic changes in bone response to transplantation and loading, the goal of this article is to document the radiographic assessment of calvarial autologous bone grafts in the recipient site. Panoramic radiographs were used to evaluate bone changes occurring during both the graft healing period and graft adaptation after implant loading. Emerging data show that conventional panoramic radiography may have an effect on the investigation of bone grafts and provide initial information about graft incorporation and adaptation.

Craniofacial reconstruction by transport distraction osteogenesis: corticotomy versus osteotomy--an experimental study

Transport osteogenesis is a modified technique of callus distraction appropriate for the reconstruction of extended osseous defects of long or flat bones. The aim of this study was to determine the regenerative potential of this technique related to the degree of mobilization of the transport segment. In 10 adult sheep, critically sized defects of the calvaria were treated by gradual movement of a transport segment consisting of calvarial bone. The transport segments were either corticotomized (n = 5) or osteotomized (n = 5). The latency period was 5 days; the rate of distraction was 1 mm/d, extended for approximately 40 days. The consolidation period was 28 days. Specimens were investigated by conventional radiography, computed tomography scans, immunofluorescence, and histological examination. In both groups, transport osteogenesis resulted in a complete closure of the defect. The volume and thickness of newly formed bone at the defect site did not differ significantly between the groups, nor did the extent of vascularization. Bone formation and remodeling occurred during the entire period of distraction and consolidation. Osteotomized transport segments became smaller during distraction, whereas the volume of corticotomized segments remained relatively constant. In conclusion, transport osteogenesis resulted in reliable closure of extended skull defects in adult organisms; corticotomy and osteotomy of the transport segment led to a similar extent of bone formation.

Assessment of the metabolic activity of bone grafts with (18)F-fluoride PET

PURPOSE

The aims of this prospective study were to evaluate quantitative approaches to (18)F-fluoride positron emission tomography (PET) imaging in allogenic bone grafts of the limbs, and to assess the time course of graft healing after surgery.

METHODS

We performed a total of 52 dynamic (18)F-fluoride PET studies in 34 patients with cancellous and full bone grafts. Seven patients were imaged three times at 6, 12, and 24 months after surgery, and four patients were imaged twice. PET data were quantitatively analyzed using non-linear regression (NLR) analysis, Patlak analysis, and standardized uptake value (SUV).

RESULTS

Fluoride bone metabolism in cancellous grafts decreased by 25% from 6 to 12 months post surgery, and revealed a total decrease of 60-65% after 2 years for SUV, K(Pat), and K(NLR). Full bone grafts first showed an increase by 20% from 6 to 12 months and from then on decreased to 70% of the initial activity at the end of 2 years with either quantification method. In two patients with non-union of their full bone grafts, increases in SUV, K(Pat), K(NLR), and K(1) far above average and outside the normal time pattern were observed. Highly significant correlations were found between SUV, K(Pat), K(NLR), and K(1) for both grafts and normal limb bones. In patients imaged repeatedly, the percentage changes in fluoride graft metabolism were also significantly correlated between SUV, K(Pat), and K(NLR).

CONCLUSION

Quantitative (18)F-fluoride PET is a promising tool for assessment of fluoride metabolism and normal healing in bone grafts of the limbs.

Quantitative assessment of early healing of intramembranous and endochondral autogenous bone grafts using micro-computed tomography and Q-win image analyzer

Micro-computed tomography (microCT) is a new tool to image and quantify trabecular bone. The aim of this study is to compare the two measurement methods when evaluating the early healing of intramembranous (IM) and endochondral (EC) autogenous bone grafts using micro-computed tomography and Q-win computer image analyzer. Twelve critical size (15 mm x 10 mm) defects were created in rabbit mandibles bilaterally. Six defects were grafted with autogenous EC bone; six defects were grafted with autogenous IM bone. Three weeks post-surgery, the defects were retrieved for microCT imaging analysis and histological evaluation. Results showed a significant correlation (r = 0.96, P < 0.0001) between microCT and Q-win in measuring the volume of new bone and graft bone in the mandibular defects after 3 weeks of early healing. There were distinct differences between IM bone and EC bone grafts in 2D and 3D features of graft bone maintenance as well as new bone formation. MicroCT imaging is a non-destructive, fast and precise procedure that allows for quantitative evaluation of the early healing of IM and EC autogenous bone grafts in membranous bone defects.