Onlay bone grafts from iliac crest: a retrospective analysis

This study was performed to address the outcomes of patients treated with onlay grafts from the iliac crest to augment the deficient jaw. The results of 173 consecutive patients who underwent bone grafting prior to implant surgery are presented. The grafts were taken from the anterior iliac crest to repair alveolar bone deficiencies that were too large to be corrected using intraoral bone grafts. Three months postoperatively, 869 implants were placed into 190 onlay grafts (167 grafts in the maxilla, 23 in the mandible). The follow-up ranged from 3 months to 23 years post implantation. All patients received a fixed prosthesis. Parameters examined included healing of the donor site and bone grafts, implant survival, peri-implant condition, and donor site morbidity. The overall survival rate for all implants was calculated to be 95% ± 2.7% according to Kaplan–Meier analysis. The implant survival rate compares favourably with those reported in studies using intraoral and extraoral bone.     

Inlay–onlay grafting for three-dimensional reconstruction of the posterior atrophic maxilla with mandibular bone

This prospective study describes and evaluates a surgical approach for 3D reconstruction of the posterior maxilla with autogenous mandibular bone in 16 patients (mean age 51 years). Bone blocks were harvested from the mandible and used as lateral or vertical block grafts (onlay); they were also partially milled and used for sinus elevation (inlay). In 4 cases, anorganic bovine bone was added at the periphery of the blocks. 4 months after grafting, implants were placed in a second operation and loaded after 12 weeks. Lateral and vertical augmentations were measured immediately after grafting and at re-entry for implant placement. Mean lateral augmentation performed was 5.5 mm, reduced to 4.3 mm (p < 0.01) after 4 months’ healing. Mean vertical augmentation was 3.2 mm, reduced to 2.1 mm (p < 0.01) after healing. The amounts of lateral and vertical graft resorption were similar (1.2 mm vs. 1.1 mm) but were different when compared with the original graft (22% vs. 34%). 49 implants were placed 4 months after grafting. Implant parameters were evaluated after 32–48 months follow up and demonstrated 100% survival rates. The use of mandibular bone grafts for 3D augmentation of the posterior maxilla has shown good results and minor complications.     

Volumetric osseous changes in the completely edentulous maxilla after sinus grafting and lateral bone augmentation: a systematic review

The aim of this systematic review was to evaluate the volumetric changes associated with different bone grafting techniques in the completely edentulous atrophic maxilla before dental implant placement. A search was performed according to the PRISMA guidelines. A PICO question was formed, and the PubMed, Scopus, Embase, and Cochrane Library databases were searched, covering the period 2000–2018. Relevant data were extracted from the results regarding study population, surgical details, technical information on volumetric data acquirement, and volumetric outcome after bone augmentation procedures before implant placement. Six articles with a combined population of 84 patients were included. All patients had a completely edentulous maxilla, with a crestal horizontal width of <3–4 mm or a crestal vertical height of <6–7 mm. The iliac bone and ascending ramus were most frequently used as grafts. Five of the six studies reported volumes of sinus inlay graft (SIG) and four reported volumes of lateral bone augmentation (LBA). Radiographic analyses of the augmented areas differed among the studies. Volume loss after bone augmentation procedures ranged from 5% to 50% for SIG and from 5% to 47% for LBA. All surgical augmentation techniques for the edentulous maxilla are prone to resorption; no procedure seemed to be superior, but some interesting observations were made.     

Staged horizontal bone augmentation for dental implants in aesthetic zones: A prospective randomized controlled clinical trial comparing a half-columnar bone block harvested from the ramus versus a rectangular bone block from the symphysis

In this study, the clinical outcomes of horizontal ridge augmentation using half-columnar bone grafts from the ramus (group I: 27 patients, 32 implants) versus rectangular bone grafts from the symphysis (group II: 19 patients, 27 implants) were compared; grafts were combined with organic bovine bone and collagen membrane. Cone beam computed tomography images were obtained preoperatively, immediately after restoration (baseline), and 1 year after loading. Four months after grafting, horizontal bone resorption at the alveolar crest did not differ significantly between the two groups (P = 0.291). At 4 mm apical to the alveolar crest, horizontal bone resorption in group I was significantly less than that in group II (P = 0.041). One year after loading, horizontal bone resorption in group I was lower than that in group II, with no significant difference. The residual thickness of the labial bone at the implant site in group I was significantly higher than that in group II. Horizontal ridge augmentation with either a half-columnar autogenous graft from the ramus or a rectangular autogenous graft from the symphysis can provide acceptable results in aesthetic regions. The half-columnar group demonstrated better graft stability both at 4 months after augmentation and 1 year after loading.     

Cone beam computed tomographic evaluation of a maxillary alveolar ridge reconstruction with iliac crest graft and implants

The present article discusses an atrophic maxilla reconstruction with iliac crest bone block and particulate grafts and dental implants. Onlay block grafts were used to restore bone volume of the anterior maxilla, whereas bilateral sinus floor augmentation was performed using a particulate graft. Ten months after the grafting surgery, 9 dental implants were placed to rehabilitate the case. Results of a 7-year follow-up were obtained clinically and by cone beam computed tomographic images.     

A 9–14 year follow-up of onlay bone grafting in the atrophic maxilla

Treatment of the atrophic edentulous maxilla is challenging especially when bone graft procedures are necessary. In this study an onlay bone graft, a saddle or veneer, with or without maxillary sinus floor inlay graft, harvested from the anterior iliac crest, in combination with implants was used in the reconstruction of patients with extreme atrophy in their maxillae. The aim was to investigate treatment outcome, and the impact of gender and smoking, in 44 patients in a prospective, long-term, follow-up study concerning implant survival rate and marginal bone loss adjacent to the surfaces of the implant.Mean follow-up time was 11 years. Of 334 inserted Brånemark implants, with machined surface, 27 failed. Estimated implant survival rate was 90%. Marginal bone loss was 1.8 mm 1 year after implant surgery; 2.3 mm after 5 years; and 2.4 mm after 10 years. There was a significant difference between genders in implant survival. Marginal bone loss differed significantly between smokers and non-smokers up to the 5-year examination and between genders after the 4-year examination. The onlay bone graft, with or without a maxillary inlay graft, results in high implant survival rate, good oral function and stabilised marginal bone. All patients are still wearing their original fixed bridges.     

Calvarial graft resorption index in the reconstruction of the maxillary sinus in patients with atrophic maxillas: a prospective clinical study

The objective of this study was to assess the resorption index of particulate calvarial grafts in maxillary sinuses of patients undergoing total reconstruction of an atrophic maxilla with residual alveolar bone that was less than, or equal to, 3 mm thick. Twenty-one maxillary sinus floor elevations were carried out using particulate calvarial grafts in 11 individuals with totally edentulous maxillas. All patients had computed tomography (CT) before (T0), and 48 hours (T1) and six months after surgery (T2). For each CT scan, linear measurements were taken of sections of the anterior, medial, and posterior regions of the maxillary sinus. There was a significant increase in the height of the maxillary sinus floor when T0 was compared with T1 (p = 0.001). There was a statistically significant reduction in all maxillary sinus measurements when T1 was compared with T2; the mean height reduction being 2.36 mm (16.87%) in the anterior region, 3.53 mm (22.47%) in the medial region, and 2.21 mm (22.78%) in the posterior region (p = 0.001). Mean resorption was 20.7%. Autogenous calvarial bone used alone is an option for graft material in pneumatised maxillary sinuses and in cases where there is limited alveolar bone.     

Marginal Bone‐Level Alterations at Implants Installed in Block versus Particulate Onlay Bone Grafts Mixed with Platelet‐Rich Plasma in Atrophic Maxilla. A Prospective 5‐Year Follow‐Up Study of 15 Patients

Background: Extensive atrophy of the alveolar process may require a bone‐grafting procedure prior to implant treatment. Autogenous bone grafts from the iliac crest, used as onlay block and particulate bone, have been used together with sinus‐lift procedure in order to rehabilitate patients with extremely resorbed maxillae. However, there are to our knowledge no 5‐year follow‐up studies evaluating the extent of bone‐level change in patients treated with respectively block and particulate autogenous bone grafts. Purpose: The purpose of this prospective clinical study was to conduct a 5‐year follow‐up analysis with focus on bone‐level alteration in block versus particulate onlay bone grafts. Material and Methods: Fifteen out of originally 19 patients who were treated with iliac bone grafts and oral implants in the maxilla have been followed through the first 5 postoperative years. In a first study conducted on 19 patients, the role of platelet‐rich plasma in conjunction with autogenous bone was evaluated. In this 5‐year follow‐up study, the marginal bone alterations have been documented at base line, 1 year and 5 years of loading to the nearest 0,1 mm at mesial and distal surfaces of the implants. Two implants were installed on each side of the midline in either block or particulate bone grafts giving test and control sides in each patient. Additionally, two implants on each side were installed in residual bone/grafted sinus floor. Result: Marginal bone alteration in the anterior maxilla appeared larger at the side augmented by block bone at baseline, and after 1 and 5 years of loading, but the change was not statistically significant. Moreover, there was a significantly higher degree of marginal alteration during the first year of loading, compared with the examinations after 5 years. Conclusion: The present follow‐up study showed that there is no significant difference in the extension of resorption between block‐ and particulate autogenous bone grafts over a 5‐year period. Most of the resorption occurred during the first year in function.     

Maxillary alveolar ridge reconstruction with monocortical fresh-frozen bone blocks: a clinical, histological and histomorphometric study

BackgroundThis investigation is a clinical and histological assessment of fresh-frozen bone use in the reconstruction of maxillary alveolar ridges. The study evaluates the effectiveness of this material as a bone filler prior the placement of dental implants.Patients and methodsSixteen patients with atrophic maxillary ridges underwent maxillary reconstruction with fresh-frozen tibial human block grafts prior to implant placement. Sampling procedures were carried out 4, 6 and 9 months later when a bone core was removed from the grafts for histological and histomorphometric analysis.ResultsEighteen blocks were placed, and each patient received either 1 or 2 blocks. During the sampling procedures, all of the grafts were found to be firm in consistency, well-incorporated, and vascularized. A total of 34 implants were placed into the grafts with a minimum of 40-Newton-cm torque in all cases. The follow-up period ranged from 18 to 30 months. No implants were lost. The histological analysis revealed vital bone with mature and compact osseous tissue surrounded by marrow spaces.ConclusionBone allografts can be used successfully as graft material for the treatment of maxillary ridge defects. This type of bone graft can be used safely in the areas of implant placement as a suitable alternative to autogenous grafts.     

Linear and volumetric gain after vertical bone augmentation in the posterior mandible using an autologous cortical tenting method

This study was performed to evaluate the linear and volumetric effects of a technique for reconstruction of the posterior atrophic mandible, including the final bone gain of the graft, by three-dimensional assessment. Thirteen individuals were recruited into the study and submitted to a total of 15 mandibular autogenous bone block surgeries. Cone beam computed tomography images were obtained at three different times. Bone graft length and thickness, and the volume, height, and width of the graft were measured. Data were compared statistically among the time points using the Friedman test, and cluster analysis was performed to identify the association between the study variables and the resorption rate (α = 0.05). Linear analysis of the width and height of the recipient area at the different time points revealed a statistically significant difference. The final average increase in height was 1.6 mm; all subjects showed an average volume gain of 3.412 mm³, and 77% of the subjects showed an average graft resorption of 0.688 mm³ construction of three-dimensional vertical defects of the posterior mandible resulted in good healing with minimal complications and minimal bone graft resorption, favouring vertical bone gain.     

Volume changes of autogenous bone after sinus lifting and grafting procedures: A 6-year computerized tomographic follow-up

ObjectivesTo evaluate long-term bone remodelling of autografts over time (annually, for 6 years), comparing the block and particulate bone procedures for sinus floor elevation, as well as to evaluate the survival of positioned dental implants.Patients and methodsTwenty-three sinus lift procedures with autogenous bone were performed: seven sinus lift procedures using particulate graft and 10 with block autogenous bone were performed in 17 patients. Employing a software program, pre- and post-surgical computerized tomography (CT) scans were used to compare the volume (V) and density (D) of inlay grafts over time (up to 6 years), and to determine the percentage of remaining bone (%R). All variable (V, D and %R) measurements were then compared statistically.ResultsAt the 6-year survey for block form, a resorption of 21.5% was seen, whereas for particulate grafts there was a resorption of 39.2%. Both groups exhibited bone remodelling between the first and second follow-up which was significant regarding volume for the block form and regarding density for the particulate group.ConclusionsDuring the initial period of healing, the cortico-cancellous block bone grafted into the maxillary sinus underwent a negative remodelling of the volume, which is most probably due to graft cortex resorption, coupled with, primarily, an increase in density in the spongious area; for the particulate grafts, significant augmentations in density were obtained. The lack of significant differences among volumes was due to the wide degree of dispersion of the data. The rough data presented in this paper seem to support the use of a bone-block grafting procedure in maxillary sinus augmentation.     

Comparative study of volumetric changes and trabecular microarchitecture in human maxillary sinus bone augmentation with bioactive glass and autogenous bone graft: a prospective and randomized assessment

The aim of this study was to compare the volumetric changes and the new bone microarchitecture in human maxillary sinuses augmented with bioactive glass (Biogran) alone, bioactive glass combined with autogenous bone graft (1:1), or autogenous bone graft alone. Twelve maxillary sinuses were grafted with bioactive glass (group 1), nine with bioactive glass mixed with autogenous bone graft 1:1 (group 2), and 12 with autogenous bone graft (group 3). Patients underwent cone beam computed tomography 15 days after the procedure to determine the initial volume of the graft (T1) and again 6 months later (T2). Biopsies were obtained at the time of dental implant placement and were subjected to micro-computed tomography. The volumetric change was 44.2% in group 1, 37.9% in group 2, and 45.7% in group 3 (P > 0.05). The trabecular microarchitecture results showed that the materials used in groups 1 and 2 were good bone substitutes. However, the addition of 50% bioactive glass to autogenous bone graft improved the microarchitecture of the graft. Furthermore, the results for volumetric changes indicated that bioactive glass, its association with autogenous bone graft in a 1:1 ratio, and autogenous bone graft alone have similar resorption.     

Influence of low-level laser therapy on the healing process of autogenous bone block grafts in the jaws of systemically nicotine-modified rats: A histomorphometric study

ObjectiveTo analyze the influence of low-level laser therapy (LLLT) on the bone healing process of autogenous bone block grafts installed in nicotine systemically modified rats.MethodsSeventy-two rats (Wistar) were randomly assigned into 4 groups (n = 18). SS-BG: saline application + bone graft. SS-BG/LLLT: saline application + bone graft + LLLT. NIC-BG: nicotine application + bone graft. NIC-BG/LLLT: nicotine application + bone graft + LLLT. After 30 days of application of solutions, all animals received autogenous bone block graft in the jaw, with the donation from the parietal bone’s calvarial area. Treatment with LLLT was in bed-graft interface, after accommodation of the graft. The animals in each group were sacrificed at 7, 14, and 28 days after graft surgery.ResultsThe histologic analyses of NIC-BG group depicted a delay of osteogenic activity in the recipient bed-graft interface and the irradiation of tissue with LLLT provided better bone healing. The histometric analysis revealed that SS-BG/LLLT and NIC-BG/LLLT groups showed increased bone formation compared to BG-SS and NIC-BG groups, after 14 days (SS-BG 24.94% ± 13.06% versus SS-BG/LLLT 27.53% ± 19.07% and NIC-BG 14.27% ± 2.22% versus NIC-BG/LLLT 24.37% ± 11.93%) and 28 days (SS-BG 50.31% ± 2.69% versus SS-BG/LLLT 58 19% ± 12.32% and NIC-BG 36.89% ± 8.40% versus NIC-BG/LLLT 45.81% ± 6.03%).ConclusionNicotine harms bone formation in the bed-graft interface and LLLT action can mitigate this.     

Influence of maxillary cortical bone thickness,implant design and implant diameter on stress around implants: A three-dimensional finite element analysis

PurposeThere is no clear evidence of the factors that could improve implant biomechanics in the posterior maxilla. Thus, a finite element analysis was performed to investigate the effect of maxillary cortical bone thickness, implant design and diameter on stress around implants.MethodsA total of 12 models of the posterior maxilla with implant were computer-simulated by varying the thickness of the alveolar cortical bone (1.5, 1.0, 0.5 or 0 mm) and implant characteristics (cylindrical implant of 4.1-mm diameter, screw-type implants of 4.1-mm or 4.8-mm outer diameters). On top of each implant, forces were separately applied axially (100 N) and buccolingually (50 N), and the von Mises stresses were calculated.ResultsRegardless of load direction, implant design and diameter, cortical and cancellous bone stresses increased with the decrease of crestal cortical bone thickness. In the absence of crestal cortical bone, cancellous bone stresses were highest and, under axial load, were transferred to the sinus floor. Implant design and diameter influenced stress to a less extent, especially under buccolingual load and in the presence of crestal cortical bone.ConclusionsFrom a biomechanical viewpoint, to improve implant success odds in the posterior maxilla, rather than implant selection, careful preoperative evaluation of the cortical bone at the planned implant site is recommended. If this cortical bone is very thin or even lacking, implant treatment should be carried on with caution by progressive loading in the range of functional loads.     

Reconstruction of the extremely atrophied mandible with iliac crest onlay grafts followed by two endosteal implants: a retrospective study with long-term follow-up

Treatment outcomes of implant-retained lower dentures on two endosseous implants placed in severely atrophied mandibles after reconstruction with iliac crest onlay grafts were assessed in a retrospective observational study. All consecutive patients treated between 2000 and 2007 were recalled in 2012 (n = 40). Survival of the implants, the condition of hard and soft peri-implant tissues, and patient satisfaction were scored. One implant was lost after 5.5 years. The mean mandibular symphysis height was 8.9 ± 2.2, 16.4 ± 2.7, 15.7 ± 2.7, and 15.4 ± 2.5 mm at intake, after augmentation, after implantation, and at the last recall visit, respectively. Mean radiographic peri-implant bone loss was 0.6 ± 0.7 mm. Mean clinical index scores were very low. Patient satisfaction was high. Surgical complications related to the donor site were seroma (n = 1), haematoma (n = 2), and sensory disturbance of the lateral femoral cutaneous nerve (n = 1); all had resolved before placement of the implants. Eleven patients reported postsurgical sensory disturbances of the mental nerve, of whom five still experienced some sensory disturbance at the last recall visit. Augmentation of the extremely resorbed mandible with an iliac crest onlay graft followed by placement of two implants 4 months later provides a solid basis for a bar-retained overdenture with favourable clinical and radiographic results.     

Minimally invasive approach with tissue engineering for severe alveolar bone atrophy case

The gold standard of bone augmentation for dental implants in severe alveolar bone atrophy is autogenous bone graft, but it has disadvantages such as limited amounts of grafted bone, poor morphological and aesthetic outcomes, and donor-site morbidity and invasiveness, especially in cases with diseases. In this reported case, the authors applied a novel tissue engineering method as minimally invasive surgery for a 58-year-old patient who had severe bone atrophy. The method, tissue-engineered bone (TEB), composed of mesenchymal stem cells as stem cells, platelet-rich plasma as growth factor and guided bone regeneration membrane. After bone regeneration by TEB, three 13 mm long dental implants were inserted. Adequate bone regeneration was shown by radiological analysis and histological observation. The augmented bone height was 4.2 mm after the operation and the radiopaque areas were increased. The clinical progress over 2 years showed a good course without bone resorption. These results indicated that TEB, as bone regeneration treatment with minimal invasiveness, could be useful as one of the novel options in dental implant treatment with severe bone atrophy.     

Clinical outcome and bone healing of implants placed with high insertion torque: 12-month results from a multicenter controlled cohort study

This study evaluated the clinical outcome and the crestal bone resorption of implants placed with high insertion torque (up to 80 N cm). 102 patients were treated with 156 tapered implants. 42 implants (control group) presented insertion torque between 30 and 45 N cm (mean = 37.4 SD 8.2). 114 implants (experimental group) were placed with insertion torque between 50 and 80 N cm (mean = 74.8 SD 7.9). All implants were early loaded after 2 months. Peri-implant marginal bone levels were assessed immediately after surgery, and at 6- and 12-month follow up examinations. At the 12-month follow up all implants were clinically stable. After 12 months, patients in the experimental group lost an average of 0.41 mm (CI 95% 0.522; 0.263) of crestal bone compared with 0.45 mm (CI 95% 0.561; 0.286) for those in the control group. There were no significant differences between the two groups. No direct or inverse relationship was observed between the insertion torque values and crestal bone resorption. The results show that the use of high insertion torque (up to 80 N cm) did not prevent osseointegration and did not increase bone resorption around tapered implants early loaded up to 1 year after implant placement.     

Osseointegration of fiber-reinforced composite implants: Histological and ultrastructural observations

ObjectivesThe aim of this study was to evaluate the bone tissue response to fiber-reinforced composite (FRC) in comparison with titanium (Ti) implants after 12 weeks of implantation in cancellous bone using histomorphometric and ultrastructural analysis.Materials and methodsThirty grit-blasted cylindrical FRC implants with BisGMA–TEGDMA polymer matrix were fabricated and divided into three groups: (1) 60 s light-cured FRC (FRC-L group), (2) 24 h polymerized FRC (FRC group), and (3) bioactive glass FRC (FRC–BAG group). Titanium implants were used as a control group. The surface analyses were performed with scanning electron microscopy and 3D SEM. The bone–implant contact (BIC) and bone area (BA) were determined using histomorphometry and SEM. Transmission electron microscopy (TEM) was performed on Focused Ion Beam prepared samples of the intact bone–implant interface.ResultsThe FRC, FRC–BAG and Ti implants were integrated into host bone. In contrast, FRC-L implants had a consistent fibrous capsule around the circumference of the entire implant separating the implant from direct bone contact. The highest values of BIC were obtained with FRC–BAG (58 ± 11%) and Ti implants (54 ± 13%), followed by FRC implants (48 ± 10%), but no significant differences in BIC or BA were observed (p = 0.07, p = 0.06, respectively). TEM images showed a direct contact between nanocrystalline hydroxyapatite of bone and both FRC and FRC–BAG surfaces.ConclusionFiber-reinforced composite implants are capable of establishing a close bone contact comparable with the osseointegration of titanium implants having similar surface roughness.     

Use of rhBMP-2 to reconstruct a severely atrophic mandible: a modified approach

This study reports the case of a patient with a severely resorbed mandible who was treated without a bone graft, using short implants, internal rigid fixation, rhBMP-2 and β-tricalcium phosphate. A 76-year-old woman, with a severely resorbed mandible (less than 3 mm), reported a history of nearly 25 years of complete edentulism and consecutive treatment failures, with total bilateral exposed inferior alveolar nerves and complete bone resorption of the inferior border in some areas. The treatment of choice was the placement of a 2.0 mm thick unilock bone plate (MatrixMandible, Synthes Maxillofacial, Paoli, PA, USA), to reinforce the mandible. Eight short implants with a regular platform (Nobel Biocare, Goteborg, Sweden) were placed: three on the external oblique line on both sides and two on the symphysis. In order to augment mandible height and coat the exposed thread of the anterior implants, rhBMP-2 (Infuse Bone, Meditronic Sofamor Danek, Memphis, TN, USA) and β-tricalcium phosphate (Cerasorb; Curasan, Kleinostheim, Germany) were used. Four 1.3 mm L miniplates were placed to support the graft. 14 months after surgery, the patient was satisfied and had excellent function without complications.     

Evaluation of postoperative changes in vascularized iliac bone grafts used for mandibular reconstruction

Vascularized iliac bone grafts are used for mandibular reconstruction, but the factors affecting graft maintenance are unknown. This study explored the postsurgical changes in vascularized iliac bone grafts in patients who had undergone mandibular reconstruction after segmental resection. The study involved 24 patients (16 men and eight women) with oral tumours or osteoradionecrosis. Thirteen patients required bare bone grafting (BBG) and 11 patients required reconstruction with soft tissue coverage (six with a skin paddle and five with direct closure). The bone graft maintenance rate (with regard to the height of the centre of the graft) was calculated immediately after surgery and at 3, 6, 12, 24, and 36 months after surgery. The maintenance rate was significantly lower in the BBG group than in the soft tissue coverage group at 3, 6, 12, 24, and 36 months, and in those who were fitted with dentures compared to those who were not at 6, 12, 24, and 36 months. Local infection also influenced the maintenance rate, but not significantly so. These findings indicate that the reconstruction technique and denture use can affect the bone graft maintenance rate after mandibular reconstruction with vascularized iliac bone grafts.