Maxillary Autogenous Bone Grafting

Comparison of Different Techniques in Post-Extractive Socket Regeneration Using Autologous Tooth Graft: Histological and Clinical Outcomes

OBJECTIVE

 Post-extractive socket grafting techniques reduce alveolar ridge dimensional changes. Numerous graft materials have been suggested and a growing interest in tooth material has been observed as a valuable alternative to synthetic biomaterials or xenografts. Furthermore, different clinical procedures have been proposed for the wound closure of the post-extractive site. This study aims to compare histological and clinical outcomes of two different surgical techniques to seal the post-extractive site with the use of autologous demineralized extracted tooth as graft material.

MATERIALS AND METHODS

 Sixteen post-extractive socket without buccal and/or palatal bone walls, in sixteen healthy patients, were grafted with the autologous tooth material treated by the new Tooth Transformer device (Tooth Transformer, Milan, Italy). Alveolar socket preservation procedures were performed without flap elevation. Patients were randomly subdivided into two equal groups according to the site closure technique. In group A, the pedunculate tissue was used, while in group B ice cone technique. A bone samples were collected in each site after 4 months for histological analysis.

RESULTS

 No significant clinical differences among the different sealing techniques were observed. In both groups, the site was filled by new bone formation after 4 months of healing. The histological analysis revealed 46.1 ± 8.07% of bone volume, 9.2 ± 9.46% of residual graft, and 35.2 ± 12.36% of vital bone in group A, while group B shows 41.22 ± 5.88% of bone volume, 7.94 ± 7.54% of residual graft, and 31.7 ± 7.52% new bone. No statistical differences were detected (p > 0.05).

CONCLUSION

 Further studies with a large number of patients, and different observation periods will be needed to confirm the results of this pilot study; however, the interesting data obtained have shown how these techniques, mixed with the autologous dentin derived graft material, seem to promote bone regeneration and reduce physiological bone resorption during alveolar socket preservation treatments.

Assessment of bone regeneration after maxillary radicular cyst enucleation with or without bone grafting materials: a retrospective cohort study

OBJECTIVE

The limitations of spontaneous bone healing underscore the necessity for exploring alternative strategies to enhance bone regeneration in maxillary radicular cyst cases. This retrospective study aimed to assess the impact of a bone substitute material (i.e., Bio-Oss) on bone volume regeneration following maxillary radicular cyst enucleation using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Seventy-three patients with maxillary radicular cysts were divided into two groups: one undergoing guided bone regeneration (GBR) with Bio-Oss and absorbable collagen membrane (n = 35), and the other receiving cyst excision alone (n = 38). Volumetric measurements using Amira software on CBCT scans evaluated bone regeneration, with cystic lesion shrinkage rates calculated. Intergroup comparisons utilized independent sample t-tests (P < 0.05), and linear regression analysis assessed the influence of preoperative cyst volume and group on bone healing.

RESULTS

Both groups showed similar success rates in bone formation at the 12-month follow-up, with no significant differences between them (mean (SD), control: 75.16 (19.17) vs. GBR: 82 (20.22), P > 0.05). Linear regression analysis revealed a negative correlation between preoperative cyst volume and bone regeneration in both groups (P < 0.05).

CONCLUSION

Bio-Oss may not significantly enhance bone augmentation in maxillary radicular cysts. In addition, preoperative cyst volume negatively affected the shrinkage rate of cystic lesions.

CLINICAL RELEVANCE

Clinicians should consider patient-specific factors such as anatomy and lesion size when determining the need for bone substitute materials. Future research could focus on optimizing treatment protocols and alternative regenerative strategies to improve patient outcomes in maxillary cyst cases.

Advances in reparative materials for infectious bone defects and their applications in maxillofacial regions

Infectious bone defects are characterized by the partial loss or destruction of bone tissue resulting from bacterial contaminations subsequent to diseases or external injuries. Traditional bone transplantation and clinical methods are insufficient in meeting the treatment demands for such diseases. As a result, researchers have increasingly focused on the development of more sophisticated biomaterials for improved therapeutic outcomes in recent years. This review endeavors to investigate specific reparative materials utilized for the treatment of infectious bone defects, particularly those present in the maxillofacial region, with a focus on biomaterials capable of releasing therapeutic substances, functional contact biomaterials, and novel physical therapy materials. These biomaterials operate via heightened antibacterial or osteogenic properties in order to eliminate bacteria and/or stimulate bone cells regeneration in the defect, ultimately fostering the reconstitution of maxillofacial bone tissue. Based upon some successful applications of new concept materials in bone repair of other parts, we also explore their future prospects and potential uses in maxillofacial bone repair later in this review. We highlight that the exploration of advanced biomaterials holds promise in establishing a solid foundation for the development of more biocompatible, effective, and personalized treatments for reconstructing infectious maxillofacial defects.

Viable cryopreserved human bone graft exhibit superior osteogenic properties in mandibular lateral augmentation

Lack of bone volume to place dental implants is frequently a problem in the reconstruction of edentulous patients. Even though autografts are the gold standard for jaw regeneration, morbidity associated with the harvesting site stimulates the demand for other substitutes. The aim of this study is to characterize the incorporation and the osteogenic ability of a viable cryopreserved human bone graft (VC-HBG) in the mandibular augmentation in rats. Bone chips from fresh human vertebrae cadaveric donors were processed, cryoprotected and deep-frozen at - 80 °C maintaining its cell viability. A jaw augmentation model was used in 20 athymic nude rats allocated into 2 groups to either receive the VC-HBG or an acellular graft as control (A-HBG). The assessment of the grafts' incorporation was performed at 4 and 8 weeks by micro-CT, histomorphometry and immunohistochemistry. Bone volume gain was significantly higher for the VC-HBG group at both time points. At 4 weeks, the A-HBG group presented significantly higher mineral density, but at 8 weeks, the VC-HBG group showed significantly higher values than the A-HBG. There was no statistical difference between VC-HBG and A-HBG groups at 4-weeks for remaining graft particles, while at 8 weeks, the VC-HBG group showed significantly less graft remnants. Collagen I, osteopontin and tartrate-resistant acid phosphatase expression were significantly higher in the VC-HBG group at both time points, while osteocalcin expression was significantly higher in the VC-HBG group at 8-weeks compared to the A-HBG group. This experimental research demonstrated that the VC-HBG shows positive osteogenic properties, greater bone formation, higher rate of bone remodeling and a better overall incorporation in rats' mandibles compared to the A-HBG.

A New Anorganic Equine Bone Substitute for Oral Surgery: Structural Characterization and Regenerative Potential

Different xenogeneic inorganic bone substitutes are currently used as bone grafting materials in oral and maxillo-facial surgery. The aim of the present study was to determine the physicochemical properties and the in vivo performance of an anorganic equine bone (AEB) substitute. AEB is manufactured by applying a process involving heating at >300 °C with the aim of removing all the antigens and the organic components. AEB was structurally characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier-transformed infrared (FT-IR) spectroscopy and compared to the anorganic bovine bone (ABB). In order to provide a preliminary evaluation of the in vivo performance of AEB, 18 bone defects were prepared and grafted with AEB (nine sites), or ABB (nine sites) used as a control, in nine Yucatan Minipigs. De novo bone formation, residual bone substitute, as well as local inflammatory and tissue effects were histologically evaluated at 30 and 90 days after implantation. The structural characterization showed that the surface morphology, particle size, chemical composition, and crystalline structure of AEB were similar to cancellous human bone. The histological examination of AEB showed a comparable pattern of newly formed bone and residual biomaterial to that of ABB. Overall, the structural data and pre-clinical evidence reported in the present study suggests that AEB can be effectively used as bone grafting material in oral surgery procedures.

Stability of Dental Implants and Thickness of Cortical Bone: Clinical Research and Future Perspectives. A Systematic Review

Dental surgery implantation has become increasingly important among procedures that aim to rehabilitate edentulous patients to restore esthetics and the mastication ability. The optimal stability of dental implants is correlated primarily to the quality and quantity of bone. This systematic literature review describes clinical research focusing on the correlation between cortical bone thickness and primary/secondary stability of dental fixtures. To predict successful outcome of prosthetic treatment, quantification of bone density at the osteotomy site is, in general, taken into account, with little attention being paid to assessment of the thickness of cortical bone. Nevertheless, local variations in bone structure (including cortical thickness) could explain differences in clinical practice with regard to implantation success, marginal bone resorption or anchorage loss. Current knowledge is preliminarily detailed, while tentatively identifying which inconclusive or unexplored aspects merit further investigation.

The rehabilitation of posterior atrophic maxilla by using the graftless option of short implant versus conventional long implant with sinus graft: A systematic review and meta-analysis of randomized controlled clinical trial

Aim

The purpose of systematic review and meta-analysis was to compare the efficacy of short implant versus conventional long implant with sinus graft in patients rehabilitated for posterior atrophic maxilla.

Setting and Design

Systematic review and meta analysis.

Materials and Methods

Electronic searches were conducted in Pub Med, Embase, and Medline with supplemented by manual search up to December 2019. The randomized controlled trial (RCTs) comparing short implant (<8.5 mm) and long implant (>8.5 mm) with sinus graft were included. (Prospero CRD42020186972).

Statistical Analysis Used

Random-effect model, fixed-effect model, A funnel plot and the Egger's test.

Results

Twenty-two Randomized controlled trials (RCTs) were assessed with 667 patients and 1595 implants (short implant:767, Long implant:835). No significant difference of implant survival rate was recorded for short and long implant (at patient level: RR: 1.01, 95% CI = 0.52-2.0, P = 0.87, I2 = 0%, at implant level RR = 1.09, 95% CI = 0.6-2.0, P = 0.7, I2 = 0%). Similarly marginal bone resorption was reported no difference for short and long implant (MD = 0.16. 95% CI: -0.23 = -0.08, P = 0.00, I2 = 74.83%). Biological complications were marginally higher for long implant (RR = 0.48, 95% CI = 0.23-0.8, P = 0.13, I2 = 29.11%). and prosthetic complications were marginally higher for short implants (RR=1.56, 95% CI=0.85-3.15, P = 0.43, I2 = 0%).

Conclusion

There was no significance difference in implant survival rate and marginal bone resorption recorded for both the short implant and long implant with sinus graft, in the patients rehabilitated with posterior atrophic maxilla. Hence, short implant is a suitable alternative to long implant with sinus graft, for the rehabilitation posterior atrophic maxilla.

Human Bone Marrow-Derived Mesenchymal Stromal Cell-Seeded Bone Biomaterial Directs Fast and Superior Mandibular Bone Augmentation in Rats

Atrophic maxillary ridges present a challenge in the field of oral implantology. Autologous bone is still considered the gold standard grafting material, but the increased morbidity and surgical complications represent a major drawback for its use. The aim of this study was to assess the efficacy of an off-the-shelf cell-seeded bone biomaterial for mandibular bone augmentation, compared to its acellular counterpart. We used a rat model to test the osteogenic properties of bone marrow-derived mesenchymal stromal cells (MSCs)-seeded bone microparticles compared to acellular bone microparticles alone. Rats were euthanized at 4 and 8 weeks, and results analyzed using micro-CT imaging, histology (H&E, Masson’s Trichrome), histomorphometry and immunohistology (Tartrate-Resistant Acid Phosphatase-TRAP, Osteocalcin and human specific anti-mitochondria antibodies). Micro-CT analysis demonstrated that the cell-seeded biomaterial achieved significantly more bone volume formation at 4 weeks (22.75 ± 2.25 mm³ vs 12.34 ± 2.91 mm³, p = 0.016) and at 8 weeks (64.95 ± 5.41 mm³ vs 42.73 ± 10.58 mm³, p = 0.029), compared to the acellular bone microparticles. Histology confirmed that the cell-seeded biomaterial was almost completely substituted at 8 weeks, in opposition to the acellular biomaterial group. Immunohistochemical analysis showed a significantly higher number of TRAP and Osteocalcin positive cells at 4 weeks in the cell-seeded group compared to the acellular group, thereby demonstrating a higher rate of bone remodeling in the presence of MSCs. The grafted human cells remained viable and were detected up to at least 8 weeks, as observed using the human specific anti-mitochondria antibody. This off-the-shelf material available in unlimited quantities could therefore represent a significant advance in the field of mandibular bone augmentation by providing a larger volume of new bone formation in a shorter time.

Chemical, Clinical and Histomorphometric Comparison between Equine Bone Manufactured through Enzymatic Antigen-Elimination and Bovine Bone Made Non-Antigenic Using a High-Temperature Process in Post-Extractive Socket Grafting. A Comparative Retrospective Clinical Study

Enzyme-deantigenic equine bone (EDEB) and anorganic bovine bone (ABB) are two xenografts made non-antigenic through different processing methods. This study aimed to characterize them for the presence of native bone collagen and other proteins and to compare their histomorphometric outcome when they were used to graft post-extractive sockets. The records of 46 patients treated with EDEB (n = 22) or ABB (n = 24) and followed-up for at least four months after delayed implant placement, were retrospectively collected. Samples of EDEB and ABB were analyzed using Attenuated Total Reflection Fourier Transform Infrared and Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis for the presence of collagen and other proteins. For histomorphometric analysis on bone specimens, newly formed bone and residual biomaterial percentages were calculated. Results of the present study show that EDEB contains type I bone collagen in its native conformation, while no proteins were detected in ABB. Grafting EDEB resulted in a significantly greater quantity of newly formed bone and less residual biomaterial. Our findings suggest that the manufacturing process can greatly affect the graft behavior and a process preserving collagen in its native form may favor bone tissue regeneration.

Titanium Mesh Grafting Combined with Recombinant Human Bone Morphogenetic Protein 2 for Alveolar Reconstruction

There are several methods of regenerating the maxillary and mandibular ridge to achieve orthoalveolar form with bone grafting procedures, including block onlay grafting and guided bone regeneration. Traditionally, guided bone regeneration has focused on creating a space for bone regeneration to occur. The use of a formed titanium mesh to regenerate alveolar defects was popularized in the 1980s. With the advent of other adjuncts, such as resorbable membranes, and growth factors, such as recombinant human bone morphogenetic protein 2, the predictability of the procedure has increased and a wide variety of defects can be restored using this technology.

Correlation between Implant Geometry, Bone Density, and the Insertion Torque/Depth Integral: A Study on Bovine Ribs

During insertion of dental implants, measurement of dynamic parameters such as the torque-depth curve integral or insertion energy might convey more information about primary stability than traditional static parameters such as the insertion or removal torque. However, the relationship between these dynamic parameters, bone density, and implant geometry is not well understood. The aim of this investigation was to compare static and dynamic implant stability measurements concerning three different implant designs when implants were inserted into bovine bone ribs and dynamic parameters were collected using an instantaneous torque measuring implant motor. Standard implant osteotomies were created in segments of bovine ribs. After measuring the bone density using the implant motor, 10 cylindrical, 10 hybrid tapered-cylindrical, and 10 modified cylindrical implants were placed, and their primary stability was assessed by measuring the torque–depth curve integral, along with insertion and removal torque. The relationship between these quantities, bone density, and implant geometry was investigated by means of regression and covariance analysis. The regression lines describing the relationship between the torque–depth integral and bone density differed significantly from those describing the relationship between insertion torque, removal torque, and bone density for all three designs. The torque–depth curve integral provides different information about immediate primary stability than insertion and removal torque and in certain clinical conditions might be more reliable than these static parameters for assessing implant primary stability. Further research should be carried out to investigate the findings of the present study.

In-Site Monocyte Implantation in Bone Grafting for Maxillary Atrophy Reconstruction: A Preliminary Observational Proof of Concept Study

PURPOSE

The main objective of this study, involving 11 patients, is to share our experience on an integrated treatment modality, namely, the use of cellular therapy simultaneously with surgical reconstruction. Published works show that the implantation of monocytes in ischemic tissue enhances healing by providing neo-angiogenesis, a key mechanism in tissue regenerative processes.

MATERIALS AND METHODS

Our approach included the utilization of autologous monocytes and endothelial precursor cells in the bone graft itself to improve the success rate of the integration of the bone graft and its long-term viability/survival by promoting angiogenesis. We compared the standard regenerative procedures, namely sinus lift grafting performed with xenogeneic particle bone graft and posterior mandible grafting performed with on-lay or in-lay autologous cortical/medullary bone-block graft harvested from the iliac crest, with and without the use of cellular implementation. We evaluated results by both radiological and histological assessment.

RESULTS

Autologous cortical/medullary bone-block graft had a different response to implementation with monocytes, showing a better osteointegration than expected conversely to the xenogeneic particle bone graft.

CONCLUSIONS

Monocytes seem to improve autologous bone-block graft according to the "Therapeutic Angiogenesis" concept. Implementation with monocytes does not always improve xenogeneic particle bone graft.

Long term follow-up of titanium implants installed in block-grafted areas: A systematic review

BACKGROUND

An enduring clinical question concerns the outcome (ie, success) of implants placed in areas grafted with block-grafts.

OBJECTIVE

To undertake a systematic review of the literature on the long term results (≥5 years) of implants placed in maxillofacial areas grafted with any type of osseous block-grafts in two-stage surgeries. Further, the review addresses how available success criteria were used within the studies.

MATERIALS AND METHODS

The MEDLINE (PubMed) and EMBASE bibliographic databases were searched up to March 2017 for studies evaluating the long term results of implants placed in grafted areas. The search strategy was restricted to English language publications using combined terms which referred to the treatment method (implants placed in areas grafted with bone blocks), and follow-up characteristics (≥5 years and assessment of at least one parameter related to implant success criteria). To qualify for inclusion, studies should present outcome measurements indicating the success (or at least the survival) of the implants.

RESULTS

The search strategy yielded 17 studies, which were included in this systematic review. These studies presented survival rates ranging from 88.7% (after 15 years follow-up) to 98.7% (after 5 years follow-up). Five studies presented data based on predefined success criteria with success rates ranging from 86.8% to 100%. In these studies, the term "success" was often not properly defined.

CONCLUSION

The long term survival (≥5 years) of implants placed into block-grafted areas in two-stage surgeries was not lower than 75%, while success rates ranged from 86.8% to 100%. Although it was possible to identify published success criteria for implant follow-up, there is no broad consensus on how to report implant success in a consistent manner.

Bone grafting for alveolar ridge reconstruction. Review of 166 cases

Objective:

to investigate the predictive factors of failure in bone grafts for alveolar ridge augmentation and implant surgery.

Methods:

we reviewed the charts of 166 patients operated between 1995 and 2014. A total of 248 grafting procedures were performed. We submitted the data to the binomial test at 5% significance.

Results:

grafts to gain width of the alveolar ridge (65.32%) were more frequent than sinus lifting (p<0.0001) and the number of grafts to the posterior maxilla (48.8%) was greater than in other regions (p<0.01); 6.04% of the grafts were lost. The losses in anterior (p<0.0309) and posterior (p<0.0132) maxilla were higher than in the mandible. There were 269 ​​implants installed in the grafted areas, of which only 4.83% were lost. The number of implants lost (4.51%) in areas of onlay grafts was not statistically higher than those placed after sinus lifting (2.63%, p<0.2424). Losses were greater in the anterior (53.85%) and posterior (38.46%) maxilla than in the mandible (p<0.031). Regarding patients' age, 76.92% of the lost grafts (p<0.006) and 80% of the lost implants (p<0.001) were installed in patients over 40 years.

Conclusion:

failure rate was higher both for grafts and dental implants in the maxilla and in patients over 40 years of age.

Objetivo:

investigar os fatores preditivos de falhas em enxertos ósseos para aumento do rebordo alveolar e cirurgia de implantes.

Métodos:

os prontuários de 166 pacientes, operados entre 1995 e 2014, foram revistos. Um total de 248 enxertos foi realizado. Os dados foram submetidos ao teste binomial a 5% de significância.

Resultados:

os enxertos para ganho em espessura do rebordo alveolar (65,32%) foram mais frequentes do que levantamentos de seio maxilar (p<0,0001) e o número de enxertos para a região posterior da maxila (48,8%) foi maior do que em outras regiões (p<0,01). Foram perdidos 6,04% dos enxertos. As perdas em maxila anterior (p<0,0132) e posterior (p<0,0309) foram maiores do que na mandíbula. Foram instalados 269 implantes nas áreas enxertadas e apenas 4,83% perdidos. O número de implantes perdidos (4,51%) em áreas de enxertos em bloco não foi estatisticamente maior do que na área de seios maxilares enxertados (2,63%) (p<0,2424). As perdas foram maiores na região anterior (53,85%) e posterior (38,46%) da maxila em relação a mandíbula (p<0,031) e, 76,92% dos enxertos (p<0,006) e 80% dos implantes perdidos (p<0,001), foram instalados em pacientes com mais de 40 anos de idade.

Conclusão:

maior taxa de falhas foi observada para enxertos e implantes dentários realizados em maxila e em pacientes com mais de 40 anos de idade.

Comparison of Two Techniques for Lateral Ridge Augmentation in Mandible With Ramus Block Graft

The purpose of this manuscript was to assess mandibular ramus block grafts used for augmentation of mandibular posterior segments, followed by subsequent implant placement. Twenty-four human subjects in need of lateral ridge mandibular augmentation were included in the current patient series.

INCLUSION CRITERIA

recipient site had at least 10-mm residual height, but less than 4.3-mm bucco-lingual dimension. Autogenous bone blocks were harvested from the mandibular ramus. In the first group ramus block was used in association with platelet-rich fibrin and in the second in association with pericardium membrane. Implant surgery was performed 4 months after bone graft surgery when a total number of 44 implants were placed. Abutments were placed 4 months after implant surgery followed by final restoration. Ramus bone graft was successful in 100% patients for the first group and in 91.67% patients for the second group. Measurement on cone beam computed tomography revealed an average of 5.35 mm of lateral ridge augmentation for group 1 and 5.099 mm for group 2, achieved 4 months after surgery. All implants placed received fixed prosthetic restorations and are in use. Ramus block grafts can be used to allow optimal implant placement, with favor long-term success. Lateral ridge augmentation using mandibular ramus bone graft in association with platelet-rich fibrin is a more predictable and successful technique.

Do Porous Titanium Granule Grafts Affect Bone Microarchitecture at Augmented Maxillary Sinus Sites? A Pilot Split-Mouth Human Study

BACKGROUND

The aim of this randomized controlled clinical study was to analyze the bone microarchitecture at augmented maxillary sinus sites by using different materials in patients to compare the effect of porous titanium granules as a sinus augmentation material with bone microstructural features.

MATERIALS AND METHODS

Eight subjects with bilateral atrophic posterior maxilla of residual bone height <4 mm included in this study and each patient was treated with bilateral sinus augmentation procedure using xenograft with equine origin (Apatos, Osteobiol; Tecnoss Dental) and xenograft (1 g) + porous titanium (1 g) granules (Natix; Tigran Technologies AB). Sixteen human bone biopsy samples were taken from patients receiving two-stage sinus augmentation therapy during implant installation and analyzed using microcomputerized tomography. Three-dimensional bone structural parameters were analyzed in details: tissue volume, bone volume, percentage of bone volume, bone surface and bone surface density, bone specific surface, trabecular thickness trabecular separation, trabecular number, trabecular pattern factor, structural model index, fractal dimension, and bone mineral density.

RESULTS

No statistically significant differences were found between groups according to bone structural parameters.

CONCLUSIONS

Porous titanium grafts may ensure a space for new bone formation in the granules, which may be a clinical advantage for long-term success.

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

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

Histologic and Tomographic Findings of Bone Block Allografts in a 4 Years Follow-up: A Case Series

Abstract The aim of this paper is to report histologic and tomographic findings of fresh frozen bone block allografts bearing dental implants in functional occlusion in a long-term follow-up. Four patients with implants functionally loaded for 4 years on augmented ridges requiring additional mucogingival surgery or implant placement were included in this case series. Cone-beam tomography scans were compared volumetrically between the baseline (first implant placement) and current images. Biopsies of the grafts were retrieved and sent to histological analysis. Volumetric reduction of the grafts varied from 2.1 to 7.7%. Histological evaluation demonstrated well-incorporated grafts with different degrees of remodeling. While data presented in this report are from a small sample size and do not allow definitive conclusions, the biopsies of the grafted sites were very similar to the host's native bone. Remodeling of the cortical portion of the allografts seems to take longer than the cancellous portion. The presence of unincorporated graft remains did not impair the implant success or the health of the surrounding tissues. This is the first time histologic and tomographic long term data of bone allograft have been made available in dentistry.

Tuberosity-alveolar block as a donor site for localised augmentation of the maxilla: a retrospective clinical study

Bone from the maxillary tuberosity has been harvested in particulate form to use for augmentation for several years, but block grafts have not been extensively used. A considerable advantage of a particulate bone graft from the maxillary tuberosity over those from other intraoral donor sites is the relative simplicity of harvesting and minimal complications. We have retrospectively assessed the efficacy of tuberosity-alveolar block bone (posterior maxillary alveolar ridge) in the augmentation of adjacent defects in the maxilla using data from 14 patients (10 men and four women, mean (range) age 55 (38-69) years) who had had 20 bony augmentations with block bone from the alveolar tuberosity during 2014. Patients were divided into three groups according to the technique by which the bone was collected. The first group had a graft from the alveolar tuberosity covered with titanium mesh (titanium mesh group); the second group had the block bone covered by platelet rich fibrin and collagen membrane (platelet rich fibrin group), and in the third group the graft was covered only with periosteum (periosteum group). The primary width of the bone was recorded at the time of placement of the graft and changes were evaluated 4-6 months later when the implant was inserted. The changes in the width of the bone were 4.1, 3.3, and 2.5 in the platelet rich fibrin, titanium mesh, and periosteum groups, respectively. The difference in bony change among groups was not significant except between the platelet rich fibrin and and periosteum groups (p=0.005). Tuberosity-alveolar block bone graft may be a good source of bone for augmentation of deficient ridges, and more favourable results can be expected by the addition of resorbable membranes and growth factors.

Stability and Crestal Bone Behavior Following Simultaneous Placement of Multiple Dental Implants (Two or More) with the Bone Splitting Technique: A Clinical and Radiographic Evaluation

PURPOSE

The present study aimed to measure the implant stability quotient (ISQ) values at three different time points after surgical procedures and crestal bone behavior in multiple implants (two or more) installed simultaneously with the bone splitting technique.

MATERIALS AND METHODS

For this study, 45 patients with different edentulous areas in the maxilla were selected, and a total of 114 dental implants were installed. Implant stability was measured by resonance frequency analysis immediately following implant placement to assess immediate stability (time 1) and stability at 90 days (time 2), and 150 days (time 3). Crestal bone height was measured in peri-apical radiographs at 90 and 150 days after implantation in relation to each implant shoulder, given that the implants were installed at the level of the crestal bone.

RESULTS

Six implants were not osseointegrated. Overall, the means and standard deviations of the ISQ values were 60.3 ± 4.94 (95% confidence interval [CI], 44-69) at baseline, 66.6 ± 5.28 (95% CI, 49-75) at 90 days, and 72.1 ± 4.28 (95% CI, 59-79) at 150 days (p < 0.0001). The mean marginal bone loss of the implants was 1.11 ± 0.61 mm on the mesial side and 1.17 ± 0.61 mm on the distal side at time 2, and 1.73 ± 0.68 mm on the mesial side and 1.79 ± 0.70 mm on the distal side at time 3. A strong positive correlation between implant stability and bone loss was detected (p < 0.0001).

CONCLUSIONS

Within the limits of this study, the bone splitting technique with simultaneous implant installation exhibited a good success rate with respect to the osseointegration index but requires attention with respect to crestal bone behavior.

Onlay bone augmentation on mouse calvarial bone using a hydroxyapatite/collagen composite material with total blood or platelet-rich plasma

OBJECTIVE

The aim of this study was to assess newly formed onlay bone on mouse calvarial bone using a new artificial bone material, a hydroxyapatite/collagen composite, with total blood or platelet-rich plasma.

DESIGN

The hydroxyapatite/collagen composite material with normal saline, total blood or platelet-rich plasma was transplanted on mouse calvarial bone. The mice were sacrificed and the specimens were harvested four weeks after surgery. The newly formed bone area was measured on hematoxylin and eosin stained specimens using Image J software.

RESULTS

The hydroxyapatite/collagen composite materials with total blood or platelet-rich plasma induced a significantly greater amount of newly formed bone than that with normal saline. Moreover, bone marrow was observed four weeks after surgery in the transplanted materials with total blood or platelet-rich plasma but not with normal saline. However, there were no significant differences in the amount of newly formed bone between materials used with total blood versus platelet-rich plasma.

CONCLUSIONS

The hydroxyapatite/collagen composite material was valid for onlay bone augmentation and this material should be soaked in total blood or platelet-rich plasma prior to transplantation.

Volumetric stability of autogenous bone graft with mandibular body bone: cone-beam computed tomography and three-dimensional reconstruction analysis

OBJECTIVES

The purpose of this study was to estimate the volumetric change of augmented autobone harvested from mandibular body cortical bone, using cone-beam computed tomography (CBCT) and three-dimensional reconstruction. In addition, the clinical success of dental implants placed 4 to 6 months after bone grafting was also evaluated.

MATERIALS AND METHODS

Ninety-five patients (48 men and 47 women) aged 19 to 72 years were included in this study. A total of 128 graft sites were evaluated. The graft sites were divided into three parts: anterior and both posterior regions of one jaw. All patients included in the study were scheduled for an onlay graft and implantation using a two-stage procedure. The dental implants were inserted 4 to 6 months after the bone graft. Volumetric stability was evaluated by serial CBCT images.

RESULTS

No major complications were observed for the donor sites. A total of 128 block bones were used to augment severely resorbed alveolar bone. Only 1 of the 128 bone grafts was resorbed by more than half, and that was due to infection. In total, the average amount of residual grafted bone after resorption at the recipient sites was 74.6%±8.4%.

CONCLUSION

Volumetric stability of mandibular body autogenous block grafts is predictable. The procedure is satisfactory for patients who want dental implants regardless of atrophic alveolar bone.

Posterior atrophic mandible rehabilitation with onlay allograft created with CAD-CAM procedure: a case report

AIM

Implant rehabilitation of the atrophic right posterior mandible in a 48-year-old woman using dehydrated homologous bone block, shaped with a computer aided design-computer aided manufacturing (CAD-CAM) system, to avoid harvesting of autologous bone block and to assure a perfect fitting of the block above the alveolar crest.

RESULTS

After 7 months, 6.09, 7.36, and 8.08 mm (mean, 7.18 mm) of total horizontal bone gain was observed at sites 6, 12, and 18 mm posterior to the right mental foramen, respectively.

CONCLUSIONS

The use of a bone block with CAD-CAM system for alveolar ridge augmentation is a valuable alternative to autograft because it reduces time, cost, and complications for the patients. Data from a computerized tomographic scan can be used to shape a precise 3-dimensional homologous bone block using a CAD-CAM system.

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

Increasingly dental surgeons face the challenge of reconstruction of the height and/or thickness of the alveolar ridge as more and more patients wish to have permanent restoration of their dental defects based on intraosseous implants. Evaluation of human allogeneic bone tissue grafts in reconstruction of atrophied alveolar ridge as a pre-implantation procedure. The material comprised 21 patients aged 19–63, treated between 2009 and 2012 by the same surgeon. Restoration of bone tissue defects was performed with allogeneic, frozen, radiation-sterilised, corticocancellous blocks. The study included 26 grafting procedures with 7 procedures consisting in reconstruction of the alveolar ridge in the mandible and 19 in the maxilla. In all the cases the atrophied alveolar ridge was successfully reconstructed, which allowed placement of intraosseous implants in compliance with the initial treatment plan. After the treatment was completed the patients reported for follow-up annually. The average time of follow-up amounted to 39 months (28–50 months). None of the implants was lost during the follow-up period. There was one case of gingival recession causing aesthetics deterioration of the prosthetic restoration. In three cases the connector became unscrewed partially, which was corrected at the same visit. Frozen, radiation-sterilised, allogeneic bone blocks constitute good and durable bone-replacement material allowing effective and long-lasting reconstruction of the atrophied alveolar ridge to support durable, implant-based, prosthetic restoration.

Horizontal-guided Bone Regeneration using a Titanium Mesh and an Equine Bone Graft

AIM

The present work describes a horizontal ridge augmentation in which a titanium mesh was preshaped by adapting it to a stereolithographic model of the patient's jaw that was fabricated from CT scans.

BACKGROUND

Guided bone regeneration (GBR) involves covering the augmentation site with a long-lasting barrier to protect it from the invasion of surrounding soft tissues. Among barriers, titanium meshes may provide a successful outcome, but the intraoperatory time needed to shape them is a disadvantage.

CASE DESCRIPTION

The 54-year-old patient, missing the right mandibular second bicuspid, first molar, and second molar, had her atrophic ridge augmented with a 30:70 mixture of autogenous bone and equine, enzyme-deantigenic collagen-preserved bone substitute. Two conical implants were inserted concomitantly in the second bicuspid and first molar positions, and the site was protected with the preshaped mesh. Four months later, the titanium mesh was retrieved, a bone sample was collected, and histological and histomorphometric analyses were performed. Provisional and definitive prostheses were then delivered, and follow-up controls were performed for up to 24 months.

CONCLUSION

Preshaping the mesh on a model of the patient's mandible shortened the surgical time and enabled faster mesh placement. Two years after surgery, the implants were perfectly functional, and the bone width was stable over time as shown by radiographic controls. Histological analysis of the bone sample showed the heterologous biomaterial to be biocompatible and undergoing advanced remodeling and replacement with newly formed bone.

CLINICAL SIGNIFICANCE

Preshaping a titanium mesh over a stereolithographic model of the patient's jaw allowed for a significant reduction of the intraoperative time and may be therefore, advisable in routine practice.

Effect of autogenous and fresh-frozen bone grafts on osteoblast differentiation

OBJECTIVE

Fresh-frozen bone allograft (FFBA) is an alternative to autogenous bone (AB) for reconstructing maxillary bone. Despite the promising clinical results, cell responses to FFBA and AB were not evaluated. Thus, our aim was to compare cells harvested from maxillary reconstructed sites with either AB or FFBA in terms of osteoblast differentiation and to evaluate the effect of culturing cells in contact with FFBA.

METHODS

Cells harvested from three patients submitted to bilateral maxillary reconstruction with AB and FFBA were cultured to evaluate: proliferation, alkaline phosphatase activity, extracellular matrix mineralization and gene expression of osteoblastic markers. The effect of FFBA on osteoblast differentiation was studied by culturing cells harvested from AB in contact with FFBA and evaluating the same parameters. Data were compared using either two-way ANOVA followed by Tukey-b test or Student's t test (p≤0.05).

RESULTS

Cell proliferation was higher in cultures from AB grafted sites and extracellular matrix mineralization was higher in cultures derived from FFBA grafted sites. The gene expression of alkaline phosphatase, RUNX2, bone sialoprotein and osteocalcin was higher in cells derived from FFBA compared with cells from AB grafted sites. However, the exposure of cells derived from AB to FFBA particles did not have any remarkable effect on osteoblast differentiation.

CONCLUSIONS

These results indicate the higher osteogenic activity of cells derived from FFBA compared with AB reconstructed sites, offering an explanation at cellular level of why FFBA could be a suitable alternative to AB for reconstructing maxillary bone defects.

Esthetic outcome of implant-based reconstructions in augmented bone: comparison of autologous and allogeneic bone block grafting with the pink esthetic score (PES)

INTRODUCTION

To determine the esthetic outcome of implant-based reconstructions after autologous and allogeneic bone grafting.

METHODS

From 2003 to 2009, 67 patients underwent alveolar ridge augmentation and were enrolled in the study, 41 meet the inclusion criteria and 31 agreed to take part in the study. Patients were 18-69 years old (mean: 49.3 ± 13.8 years), and predominantly female. Patients received bone block grafts either autologous (n = 48) (AUBB) or allografts (ABB) (n = 19). Implants were inserted 4-7 months (autografts) or 5-6 months (allografts) after bone grafting. The Pink Esthetic Score (PES) as well as radiographic and subjective assessments were employed for the outcome analysis. The PES was assessed twice within one month based on digital photographic images that were randomly rearranged between evaluations by three independent, experienced investigators.

RESULTS

Across all observations and investigators, the average PES was 7.5 ± 2.6 without differences between implants inserted in auto- and allografted bone, respectively. Patients assessed the allograft procedures as less painful and would have repeated it more often. The intra-rater reliability was excellent (correlation coefficients 0.7-0.9). The inter-observer agreement was lower (correlation coefficients 0.6-0.8).

CONCLUSIONS

Bone grafting with ABB allografts yields equivalent results to autologous grafting, and patients appreciate the omission of bone harvesting. The PES is a reliable method but should be performed by the same individual.

Time-dependent changes in fresh-frozen bone block grafts: tomographic, histologic, and histomorphometric findings

BACKGROUND

Bone allografts have shown satisfactory clinical results in alveolar ridge reconstructions. However, the process of incorporation and the resorption rates of these grafts are not yet fully understood.

PURPOSE

The aim of this study was to use computed tomography (CT), histology, and histomorphometry to assess the time-dependent rates of resorption and incorporation of fresh-frozen bone allografts.

MATERIALS AND METHODS

Twenty-four patients underwent alveolar ridge reconstruction with bone block allografts and were randomly allocated to three groups with different graft healing periods (4, 6, or 8 months) before implant placement. To assess the resorption rates, CT scans were acquired within 7 days after bone graft surgery and at the end of the period. Graft samples were collected and sent for histological and histomorphometric analyses.

RESULTS

The graft resorption mean rates were 50.78% ± 10.43, 32.77% ± 7.84, and 13.02% ± 3.86 for the 4-, 6-, and 8-month groups, respectively, and were significantly different among the three groups. Newly formed bone with osteocytes near the grafted bone was observed in all three groups. The number of osteocytes was significantly lower at 4 months. Grafted bone remains were significantly higher in the shortest period of time. All of the grafts showed large amounts of calcified tissue.

CONCLUSIONS

All three groups showed new bone formation and different bone resorption rates. Graft healing periods of 4 months showed less graft resorption and seemed to be the most favorable for implant placement. Healing periods of 8 months showed the largest rate of graft resorption, which could render the grafts unfavorable for implant placement.

Osteogenic differentiation of human dental pulp stem cells on β-tricalcium phosphate/poly (l-lactic acid/caprolactone) three-dimensional scaffolds

Functional tissue engineering for bone augmentation requires the appropriate combination of biomaterials, mesenchymal stem cells, and specific differentiation factors. Therefore, we investigated the morphology, attachment, viability, and proliferation of human dental pulp stem cells cultured in xeno-free conditions in human serum medium seeded on β-tricalcium phosphate/poly(l-lactic acid/caprolactone) three-dimensional biomaterial scaffold. Additionally, osteogenic inducers dexamethasone and vitamin D₃ were compared to achieve osteogenic differentiation. Dental pulp stem cells cultured in human serum medium maintained their morphology; furthermore, cells attached, remained viable, and increased in cell number within the scaffold. Alkaline phosphatase staining showed the osteogenic potential of dental pulp stem cells under the influence of osteogenic medium containing vitamin D₃ or dexamethasone within the scaffolds. Maintenance of dental pulp stem cells for 14 days in osteogenic medium containing vitamin D₃ resulted in significant increase in osteogenic markers as shown at mRNA level in comparison to osteogenic medium containing dexamethasone. The results of this study show that osteogenic medium containing vitamin D₃ osteo-induced dental pulp stem cells cultured in human serum medium within β-tricalcium phosphate/poly(l-lactic acid/caprolactone) three-dimensional biomaterial, which could be directly translated clinically.

A novel bioactive vitroceramic presents similar biological responses as autogenous bone grafts

Bioactive glasses represent an interesting class of bone substitute's biomaterials. The present study investigated the repair of bone defects filled with a novel bioactive vitroceramic (Biosilicate(®)), alone or in association with particulate autogenous bone grafts in calvaria defects of rabbits. After 7, 14, and 30 days the specimens were retrieved for histological, histomorphometric and immunohistochemistry analysis. Satisfactory bone formation was observed in all groups, and direct bone-biomaterial surface was noted. Histomorphometric assessment did not show statistically significant differences in bone formation among the groups and periods, except for BG group at day 14. Immunoexpression of Runx-2 was similar among the groups containing the graft and the biomaterial, being more intense than in control group. Similar result was observed for VEGF expression, especially in the last experimental period. These results revealed that Biosilicate(®) presented a favorable behavior, comparable to autogenous bone graft.