Bone Graft Resorption Research Articles

Utilité du scanner pour la détection de la résorption des greffes osseuses glénoïdiennes dans les prothèses inversées d’épaule

IntroductionGlenoid bone grafting is often used in cases of reverse shoulder arthroplasty (RSA) with glenoid deficiency. Additionally, bony increased-offset RSA (BIO-RSA) uses a cylindrical bonegraft harvested from the humeral head and is positioned beneath the glenoid baseplate to increase lateralization. Post-operative computed tomography (CT) has been used to detect glenoid bonegraft resorption, which is typically identified by a gap between the bonegraft and baseplate; however, CT images are often degraded by implant metal artifact. The purpose of this CT imaging study was to determine if a simulated bonegraft resorption gap is detectable following RSA with glenoid bone grafting. HypothesisCT is unable to detect bone graft resorption following reverse shoulder arthroplasty conducted with bone grafting beneath the glenoid baseplate. Materials and methodsRSA with glenoid bone grafting was performed on four cadaver shoulders. Glenoid bonegraft resorption gaps were simulated by fixing the implant at six different gap widths (0, 1, 2, 4, 6 and 8mm). Clinical CT scans were acquired for each gap resulting in six scans per specimen. Two experienced observers (blinded) analyzed DICOM images in the axial and coronal directions, and measured gap widths using Mimics® software. Approximately 200images per specimen were viewed by each observer, for a total of 1600 images. ResultsThe sensitivity of CT imaging to positively identify bonegraft resorption was 38%, with an accuracy of 46%. Inter-observer agreement was 92%. Observers tended to visualize no-gap for most conditions. Resorption gap width measurements were consistently underestimated. DiscussionMetal artifact prevented identification of simulated bonegraft resorption gaps and observers most often determined that there was bonegraft-to-implant “healing” on CT, when in fact a gap was clinically present. This study illustrates the need for more effective imaging techniques to determine if bonegraft resorption has occurred following RSA. Level of evidenceLevel IV. Basic science; cadaveric study.

Effectiveness of CT for the detection of glenoid bone graft resorption following reverse shoulder arthroplasty

IntroductionGlenoid bone grafting is often used in cases of reverse shoulder arthroplasty (RSA) with glenoid deficiency. Additionally, bony increased-offset RSA (BIO-RSA) uses a cylindrical bonegraft harvested from the humeral head and is positioned beneath the glenoid baseplate to increase lateralization. Postoperative computed tomography (CT) has been used to detect glenoid bonegraft resorption, which is typically identified by a gap between the bonegraft and baseplate; however, CT images are often degraded by implant metal artifact. The purpose of this CT imaging study was to determine if a simulated bonegraft resorption gap is detectable following RSA with glenoid bone grafting. HypothesisCT is unable to detect bone graft resorption following reverse shoulder arthroplasty conducted with bone grafting beneath the glenoid baseplate. Materials and methodsRSA with glenoid bone grafting was performed on four cadaver shoulders. Glenoid bonegraft resorption gaps were simulated by fixing the implant at six different gap widths (0, 1, 2, 4, 6 and 8mm). Clinical CT scans were acquired for each gap resulting in 6 scans per specimen. Two experienced observers (blinded) analyzed DICOM images in the axial and coronal directions, and measured gap widths using Mimics® software. Each observer had access to approximately 200 images per condition per specimen. ResultsThe sensitivity of CT imaging to positively identify bonegraft resorption was 38%, with an accuracy of 46%. Inter-observer agreement was 92%. Observers tended to visualize no-gap for most conditions. Resorption gap width measurements were consistently underestimated. DiscussionMetal artifact prevented identification of simulated bonegraft resorption gaps and observers most often determined that there was bonegraft-to-implant “healing” on CT, when in fact a gap was clinically present. This study illustrates the need for more effective imaging techniques to determine if bonegraft resorption has occurred following RSA. Level of evidenceLevel IV. Basic Science; Cadaveric Study.

Restoration of Oral Function for Adult Edentulous Patients with Ectodermal Dysplasia: A Prospective Preliminary Clinical Study.

Therapy with zygomatic implants (ZIs) or conventional implants (CIs) has proven to be an effective method to restore oral function for systemically healthy patients. However, it is still a major challenge to fully restore oral function to edentulous adult patients with ectodermal dysplasia (ED). The aim of this study was to determine an effective treatment protocol for restoring oral function using ZIs and CIs to edentulous adult ED patients. Ten edentulous adult ED patients were treated in this study. The treatment protocol involved the following: (1) bone augmentation in the region of the anterior teeth; (2) placement of two ZIs and four CIs in the maxilla, and four CIs in the mandible; (3) fabrication of dental prosthesis; and (4) psychological and oral education. Following treatment of these patients, implant success rates, biological complications, patient satisfaction, and psychological changes were recorded. Although there was evidence of bone graft resorption in the maxilla, bone augmentation of the mandible was successful in all patients. Nine CIs in the maxilla failed and were removed. All ZIs were successful, and the CIs success rates were 77.50% in the maxilla and 100% in the mandible, with a mean of 88.75%. The mean peri-implant bone resorption for the CIs ranged from 1.3 ± 0.4 mm to 1.8 ± 0.6 mm, and four cases exhibited gingival hyperplasia in the maxilla and mandible. One hundred percent of the patients were satisfied with the restoration of their oral function, and >50% of the patients exhibited enhanced self-confidence and self-esteem. This study demonstrates that oral function can be restored in edentulous adult ED patients using a comprehensive and systematic treatment protocol involving psychological and oral education, bone augmentation, implant placement, and denture fabrication. Despite these positive outcomes, bone augmentation remains challenging in the anterior region of the maxilla for edentulous adult ED patients.

Computer-assisted design of sequential surgical procedure for oblique facial clefts with mandibular outer cortex autografts.

Oblique facial clefts are congenital craniofacial malformations affecting the paramedian line of facial structures. Correction of these defects involves bone and soft tissue reconstruction. The authors have developed a computer-aided sequential surgical procedure for oblique facial clefts, including mandibular outer cortex autografting, medial canthal ligament reduction and fixation, and fat autografting. From 2004 to 2013, 12 patients (9 women, 3 men) with oblique facial clefts were treated with the 3-step procedure in our clinic. Mean patient age at the first surgery was 18 years (range, 13-25 years). Preoperative three-dimensional surgical simulations assisted the surgeries. A retrospective review of patients' clinical, photographic, and radiographic records was performed. All patients achieved significant treatment effects and high satisfaction. The patients' self-assessed scores on a 10-point scale of deformity severity were lower after surgery (P < 0.001) and remained stable after 6 to 12 months (P = 0.069). Good repositioning of the inner canthus was achieved (P < 0.001) with no significant relapse (P = 0.096). The mean (SD) recovery of mandibular donor sites was 48.44% (16.89%) (range, 11.03%-71.33%). Grafted bone absorption was not significantly different at different recipient sites. Only minor complications occurred in 6 patients. This procedure was an effective treatment for oblique facial clefts, resulting in high satisfaction, remarkable improvements in facial symmetry, little skin scarring, acceptable bone graft resorption, and dramatic recovery of mandibular donor sites. Computer-assisted surgical simulation effectively describes characteristic skeletal deformities and provides a useful guide to surgical reconstruction.

Influence of Maxillary Sinus Width on Transcrestal Sinus Augmentation Outcomes: Radiographic Evaluation Based on Cone Beam CT.

Maxillary sinus elevation is a predictable procedure to vertically enhance bone volume in the posterior maxilla for successful implant placement. It is speculated that graft bone resorption and remodeling which require angiogenesis may be affected by the dimensions of maxillary sinus cavity. The aim of this study is to investigate the effect of sinus width (SW) on the outcomes of transcrestal sinus lift with simultaneous implant placement based on cone beam CT (CBCT). A total of 57 elevated sites in 33 patients were included in this study. All the patients were treated with transcrestal sinus lift procedure associated with simultaneous implant placement using a composite graft material of autogenous bone and Bio-Oss. For each patient, CBCT scans were performed preoperatively, immediately after surgery and 6 months after surgery. Measurements of the linear parameters were conducted on the preoperative and postoperative CBCT images. The correlation of SW with graft resorption (GR) was analyzed using Pearson's correlation test with or without the classification of residual bone height. The average width of maxillary sinus was 13.68 ± 2.66 mm. The mean height of apical graft bone decreased from 2.85 mm immediately after surgery to 1.38 mm after 6 months. A positive association between SW and GR (r = 0.323, p = .014) was found in general. The findings show that graft bone resorption in elevated sinus has a positive correlation with the SW.

Results of an open posterior bone block procedure for recurrent posterior shoulder instability after a short- and long-time follow-up.

The aim of the present study was to analyse and compare the clinical and radiological results after open posterior bone block procedure at long- (LT) and short-term (ST) follow-up. The hypothesis was that placement of a bone block at the posterior glenoid rim in a technique of extending the glenoid surface will create permanent joint stability even in cases with hyperlaxity without a clinically relevant loss of motion or increase in osteoarthritis. Fifteen consecutive shoulders with recurrent posterior dislocation were evaluated clinically and radiologically. The Rowe score, Western Ontario Shoulder Index, Walch-Duplay score and the Constant-Murley score were used for clinical evaluation. The patients were categorized according to their follow-up period as either ST follow-up (min 12 months) or LT follow-up (min 42 months). The clinical results showed no significant difference between ST (9) and LT (6) with good to very good overall results in the subjective as well as the objective scores (CS, RS, WDS). At LT, most patients felt mild to minor pain under strain. The difference in pain between the groups was not significant. Active ranges of motion and strength assessments were normal in all cases. In one case, recurrent dislocations occurred after bone graft resorption 6 months post-operatively. Only one patient presented mild osteoarthritis, without further progress at follow-up. The open posterior bone block procedure can be a successful treatment option for recurrent posterior shoulder instability at ST and LT follow-up. This series showed a low rate of recurrent dislocations without development or progression of osteoarthritis. Since soft tissue procedures do not always provide satisfying results, the posterior bone block augmentation presents a reliable technique for the treatment of symptomatic posterior instability. Case Series, Treatment Study, Level IV.

Deproteinized bovine bone remodeling pattern in alveolar socket: a clinical immunohistological evaluation.

Considering the low rate of deproteinized bovine bone (DBB) graft resorption in vivo and vitro, the aim of this study was to investigate, through an immunohistochemical method, DBB remodeling patterns in human. Socket preservation, a highly documented and affirmed technique, was selected as the best in vitro model to analyze DBB effect on bone remodeling. Following premolar extraction (T0), 20 patients were randomized into two treatment groups. In the test group (t), the alveolar sockets were grafted with DBB, while in the control group (c) no bone graft was applied and the alveolar sockets were left to heal spontaneously. After 5 months, a re-entry procedure was performed, and one implant was placed according to manufacturer's protocols (T1). Bone biopsies were harvested for each patient both at T0 and at T1. On the bone samples, immunohistochemical investigations were performed to analyze BMP-2, BMP-7, ALP, IL-6, TNF-α expression. Bone morphogenetic proteins were more expressed in the control group than in the test group (BMP-2: P < 0.001; BMP-7: P = 0.017), while TNF-α value was larger in the test group (P < 0.001); no statistically significant differences were observed for the other markers. When considering time as the main variable, statistically significant differences were found for BMP-2 (P < 0.001), BMP-7 (P < 0.001), IL-6 (P < 0.001), ALP (P < 0.05), and TNF-α (P < 0.001). Significant interaction between groups and time was found for BMP-2 (P < 0.001), BMP-7 (P < 0.001), TNF-α (P < 0.001). Deproteinized bovine bone guarantees the activity of bone remodeling processes in human extraction socket at 5 months of healing, bringing to a higher expression of anabolic and catabolic bone markers.

Prospective tomographic evaluation of autogenous bone resorption harvested from mandibular ramus in atrophic maxilla.

Autogenous bone is considered the criterion standard for grafting procedures of severely resorbed alveolar ridges. However, the rate of autogenous graft resorption remains controversial. The aim of this study was to evaluate the mandibular graft resorption with cone beam computed tomography after 10 and 180 days of augmentation procedures in the atrophic maxilla. Twenty-two patients received 36 autogenous bone grafts harvested from the mandibular ramus. Tomographical evaluations were carried out after 10 (T1) and 180 (T2) days of augmentation procedures to obtain bone grafts area measurements. After 10 days postoperatively (T1), the mean area of bone graft was 81.38 mm (range, 46.33-113.73 mm), whereas, after 180 days postoperatively (T2), the mean area of bone graft was 66.13 mm (range, 33.51-101.93 mm). The mean percentage variation of graft resorption between T1 and T2 was 18.38%. Autogenous bone blocks harvested from the mandibular ramus presented a reduction of 18.38% in the measurement areas after the augmentation procedures in the atrophic maxilla. Therefore, the use of autogenous bone blocks remains as a viable and predictable procedure for the rehabilitation of the atrophic maxillae. Thus, other studies must be carried out to improve the knowledge on the bone graft resorption, which may serve as a basis for the development of more effective strategies for the rehabilitation of patients with an atrophic maxilla.

Implant angulation: 2-year retrospective analysis on the influence of dental implant angle insertion on marginal bone resorption in maxillary and mandibular osseous onlay grafts.

The purpose of this study was to determine the existence of correlations between marginal peri-implant linear bone loss and the angulation of implants in maxillary and mandibular augmented areas over the course of a 2-year survey. Dependent variables described the sample of the present retrospective chart review. By using three-dimensional radiographs, input variables, describing the implant angulation (buccal-lingual angle [φ] and mesial-distal angle [θ]) were measured; outcome variables described survival rate and marginal bone resorption (MBR) around dental implants in autogenous grafts (10 maxillae and 14 mandibles). Pairwise comparisons and linear correlation coefficient were computed. The peri-implant MBR in maxillary buccal and palatal areas appeared less intensive in the presence of an increased angulation of an implant towards the palatal side. Minor MBR was recorded around mandibular dental implants positioned at a right angle and slightly angulated towards the mesial. Resorption in buccal areas may be less intensive as the angulation of placed implants increases towards the palatal area in the maxilla, whereas for the mandible, a greater inclination towards the lingual area could be negative. In the mandibular group, when the implant was slightly angulated in the direction of the distal area, bone resorption seemed to be more marked in the buccal area. In the planning of dental implant placement in reconstructed alveolar bone with autograft, the extremely unfavourable resorption at the buccal aspect should be considered; this marginal bone loss seemed to be very sensitive to the angulation of the dental implant.

History of synthetic materials in alloplastic cranioplasty

When faced with calvarial defects, surgeons have long searched for repair materials. General criteria include ease of use, low cost, availability, cosmetic shape, and osteointegrative potential. While autologous bone is widely used and favored in contemporary reconstructive procedures, synthetic alternatives have been used throughout history and are necessary in current practice for select cases when autograft reconstruction is not an option (such as cases with severe bony comminution, bone graft resorption, infection, and limited donor site options). For centuries, surgeons have experimented with metals, ceramics, plastics, and later, resorbable polymers. This paper provides a tour of the materials that have been used and experimented with throughout the history of alloplastic cranioplasty.

Prevention of the surface resorption of bone grafts by topical application of bisphosphonate on different carrier materials

The hypothesis of the present study was that topically applied bisphosphonate (BP) on a collagen membrane or alternatively bovine bone mineral prevents surface resorption of onlay bone grafts. In eight adult pigs, bone blocks were harvested bilaterally from the mandible and fixed to the lateral cortex of the horizontal ramus to simulate a ridge augmentation. In a split-mouth study design, we used alendronate in aqueous solution (1mg/ml) on the test-side in three different ways: on a collagen membrane (Bio-Gide®), soaked in bovine bone mineral granules (Bio-Oss®), or applied to the bone graft directly. The same materials without BP were used as controls on the contralateral side. After 3months, the animals were sacrificed. The evaluation included sequential fluorochromic labeling and measurement of bone height in microradiography and toluidine blue staining. In five cases, necrosis of the overlying periosteal tissues with BP was observed macroscopically. A statistically significantly lower loss in graft height was seen on the test-side for Bio-Gide® + alendronate (0.65%) versus Bio-Gide® (1.52%), p = 0.002; Bio-Oss® + alendronate (1.16%) versus Bio-Oss® (4.20%), p = 0.001; and bone graft + alendronate (1.25%) versus bone graft alone (6.01%), p = 0.006. An inhibitory effect on bone remodeling was observed by a statistically significantly lower number of resorption lacunae. The hypothesis was accepted that a bisphosphonate-treated membrane reduced bone graft resorption; however, periosteal necrosis requires better adaptation of the dosage. A bisphosphonate membrane could be a helpful tool to preserve augmentation height of onlay bone grafts.

Impact of bone graft harvesting techniques on bone formation and graft resorption: a histomorphometric study in the mandibles of minipigs

Harvesting techniques can affect cellular parameters of autogenous bone grafts in vitro. Whether these differences translate to in vivo bone formation, however, remains unknown. The purpose of this study was to assess the impact of different harvesting techniques on bone formation and graft resorption in vivo. Four harvesting techniques were used: (i) corticocancellous blocks particulated by a bone mill; (ii) bone scraper; (iii) piezosurgery; and (iv) bone slurry collected from a filter device upon drilling. The grafts were placed into bone defects in the mandibles of 12 minipigs. The animals were sacrificed after 1, 2, 4 and 8 weeks of healing. Histology and histomorphometrical analyses were performed to assess bone formation and graft resorption. An explorative statistical analysis was performed. The amount of new bone increased, while the amount of residual bone decreased over time with all harvesting techniques. At all given time points, no significant advantage of any harvesting technique on bone formation was observed. The harvesting technique, however, affected bone formation and the amount of residual graft within the overall healing period. Friedman test revealed an impact of the harvesting technique on residual bone graft after 2 and 4 weeks. At the later time point, post hoc testing showed more newly formed bone in association with bone graft processed by bone mill than harvested by bone scraper and piezosurgery. Transplantation of autogenous bone particles harvested with four techniques in the present model resulted in moderate differences in terms of bone formation and graft resorption.

Biological Response to β-Tricalcium Phosphate/Calcium Sulfate Synthetic Graft Material

The aim of this study was to evaluate the effect of a biphasic synthetic bone graft material composed of β-tricalcium phosphate (β-TCP) and calcium sulfate (CS) in 12 New Zealand rabbits. A circular bicortical critical-size cranial defect was created in each of 12 rabbits. The defects were grafted with β-TCP/CS. Animals were euthanized at 3 and 6 weeks. Harvested tissue specimens were evaluated histologically and histomorphometrically. Parameters associated with new bone formation and graft resorption were measured and calculated. The results were statistically analyzed using the Mann-Whitney test. Our data demonstrated the biocompatibility of synthetic β-TCP/CS, as no inflammatory response was observed, and no fibrosis was developed between the graft particles and the newly formed bone. Moreover, β-TCP/CS acted as an osteoconductive scaffold that allowed a significant bone regeneration and graft biodegradation with time. In this animal model, synthetic β-TCP/CS proved to be a biocompatible, osteoconductive, and bioresorbable bone graft substitute.

Timing of cranioplasty after decompressive craniectomy for trauma.

Background:The optimal timing of cranioplasty after decompressive craniectomy for trauma is unknown. The aim of this study was to determine if early cranioplasty after decompressive craniectomy for trauma reduces complications.Methods:Consecutive cases of patients who underwent autologous cranioplasty after decompressive craniectomy for trauma at a single Level I Trauma Center were studied in a retrospective 10 year data review. Associations of categorical variables were compared using Chi-square test or Fisher's exact test.Results:A total of 157 patients were divided into early (<12 weeks; 78 patients) and late (≥12 weeks; 79 patients) cranioplasty cohorts. Baseline characteristics were similar between the two cohorts. Cranioplasty operative time was significantly shorter in the early (102 minutes) than the late (125 minutes) cranioplasty cohort (P = 0.0482). Overall complication rate in both cohorts was 35%. Infection rates were lower in the early (7.7%) than the late (14%) cranioplasty cohort as was bone graft resorption (15% early, 19% late), hydrocephalus rate (7.7% early, 1.3% late), and postoperative hematoma incidence (3.9% early, 1.3% late). However, these differences were not statistically significant. Patients <18 years of age were at higher risk of bone graft resorption than patients ≥18 years of age (OR 3.32, 95% CI 1.25-8.81; P = 0.0162).Conclusions:After decompressive craniectomy for trauma, early (<12 weeks) cranioplasty does not alter the incidence of complication rates. In patients <18 years of age, early (<12 weeks) cranioplasty increases the risk of bone resorption. Delaying cranioplasty (≥12 weeks) results in longer operative times and may increase costs.

Resorption of Autogenous Bone Graft in Cranioplasty: Resorption and Reintegration Failure.

ObjectiveRe-implantation of autologous skull bone has been known to be difficult because of its propensity for resorption. Moreover, the structural characteristics of the area of the defect cannot tolerate physiologic loading, which is an important factor for graft healing. This paper describes our experiences and results with cranioplasty following decompressive craniectomy using autologous bone flaps.MethodsIn an institutional review, the authors identified 18 patients (11 male and 7 female) in whom autologous cranioplasty was performed after decompressive craniectomy from January 2008 to December 2011. We examined the age, reasons for craniectomy, size of the skull defect, presence of bony resorption, and postoperative complications.ResultsPostoperative bone resorption occurred in eight cases (44.4%). Among them, two experienced symptomatic breakdown of the autologous bone graft that required a second operation to reconstruct the skull contour using porous polyethylene implant (Medpor®). The incidence of bone resorption was more common in the pediatric group and in those with large cranial defects (>120 cm2). No significant correlation was found with sex, reasons for craniectomy, and cryopreservation period.ConclusionThe use of autologous bone flap for reconstruction of a skull defect after decompressive craniectomy is a quick and cost-effective method. But, the resorption rate was greater in children and in patients with large skull defects. As a result, we suggest compressive force of the tightened scalp, young age, large skull defect, the gap between bone flap and bone edge and heat sterilization of autologous bone as risk factors for bone resorption.

Correlation between density and resorption of fresh-frozen and autogenous bone grafts.

Trial Design. This analysis compared the outcome of fresh-frozen versus autologous bone block grafts for horizontal ridge augmentation in patients with Cawood and Howell class IV atrophies. Methods. Seventeen patients received autologous grafts and 21 patients received fresh-frozen bone grafts. Patients underwent CT scans 1 week and 6 months after surgery for graft volume and density analysis. Results. Two autologous and 3 fresh-frozen grafts failed. Autologous and fresh-frozen grafts lost, respectively, 28% and 46% of their initial volume (P = 0.028). It is noteworthy that less dense fresh-frozen blocks lost more volume than denser grafts (61% versus 16%). Conclusions. According to these 6-month results, only denser fresh-frozen bone graft may be an acceptable alternative to autologous bone for horizontal ridge augmentation. Further studies are needed to investigate its behaviour at longer time points.

Commentary to "Survival rate of Astra Tech implants with maxiilary sinus lift"

I had the chance to read a recently published article by Yoon et al.1 entitled 'Survival rate of Astra Tech implants with maxillary sinus lift'. The authors performed a retrospective evaluation of the clinical survival rate of TiO-blast surface-treated Astra Tech implants after transalveolar or lateral approach sinus floor elevation with bone grafts. Although their clinical survival rate was 90.9% (n=99) and this was considered a success, there are still several concerning factors to consider. With my limited knowledge and experience, I would like to express some of my opinions for authors' kind review. First of all, this study would have been greatly improved if the author set more detailed inclusion/exclusion criteria. The authors included too many types of grafting materials without considering the outcome of a corresponding material in different sinus augmentation techniques; lateral and transalveolar technique. There are too many variables to consider in this study. Although the authors provided references indicating that there are no statistical differences related to the type of bone graft materials or approach, this does not necessary mean that those criteria are completely nonsignificant factors in implant survival. I would like to carefully state that the authors generalized and over-simplified factors based on limited references. Specifically, the authors referenced a study by Jurisic et al.2 to support that there are not significant differences between the two sinus floor elevation techniques1. However, the minimum alveolar bone height for sinus elevation in Jurisic et al.'s study2 was 4 mm, whereas that of Yoon et al.'s study1 was 1.2 mm. A study by Geurs et al.3 found a significant difference in implant loss when residual bone height was less than 4 mm, as compared to 5 mm or greater. The authors should not have drawn a conclusion solely based on one other similar study. The referenced study by Jurisic et al.2 is not the same as the study done by Yoon et al.1, and thus the authors should have provided their own statistical analysis as to whether or not there was a correlation between the two different techniques and implant survival. The same could be said of bone grafting type. Even though xenogenic bone grafting has been used in many cases, as the authors stated, it would have been nice if statistical analysis was provided. Furthermore, the authors concluded that there was no correlation between approach to the maxillary sinus or bone graft material used and implant failure, but again, no statistical analysis was applied to provide evidence for such a conclusion. Additionally, I would expect a more explicit explanation for implant failure. Perhaps implants failed due to low alveolar bone height, eventful resorption of bone grafts or complications from surgery. Furthermore, the authors failed to provide some surgical details, such as how many implants and what kind of sinus floor elevation approach were used, and whether a one- or two-stage technique was employed. Lastly, the survival rate should be compared to other published studies4,5. The presented survival rate was 90.9%1, while the most recent systemic reviews stated that the annual rough surface implant survival rate using the lateral window technique with bone graft was 96.5% after 3 years4. Survival of implants using the transalveolar technique after 3 years and at least 1 year of functional loading was 92.8%5. Although Yoon et al.'s study included both transalveolar and lateral approaches in calculating survival rate, it is still important to describe the meaning of their acquired survival rate. The authors should be credited for their hard work in preparing this extensive retrospective study. However, the lack of reader-friendly and detailed tables remains a limitation of this study, followed by the lack of statistical analysis and discussion. A sufficient number of sample sizes with a uniform implant system indicate that the study was well designed. I would be delighted to actively participate in your future basic and clinical implant dentistry research. Also, I would be thrilled to read better quality work from these authors in the near future.

Resorption of bone graft after maxillary sinus grafting and simultaneous implant placement.

ObjectivesThe purpose of this study was to evaluate the sinus bone graft resorption over 3 years after two-stage implant placement.Materials and MethodsThe subjects for this study included 30 patients whose maxillary posterior ridges were too atrophic for implants. Bone-added osteotome sinus floor elevation was used in 15 maxillary sinuses, while the bone graft by lateral approach technique was used in 25 maxillary sinuses. The height from the top of the fixture to the sinus floor was estimated immediately after implant placement and the follow-up period was over 3 years. The surgery was classified with two groups: sinus bone grafting with and without autogenous bone. All implants were placed simultaneously.ResultsThe mean vertical bone loss was 3.15±2.95 mm. The survival rate of implants was 94.7%.ConclusionThe amount of bone resorption was not significantly associated with the surgical methods, the type of bone graft materials used, or sinus perforation during surgery.

Design and Manufacturing Preparation of a Patient Specific Acetabular Cage

Total hip arthoplasty or hip replacement is today a common and highly successful a surgical procedure. However, in the revision artoplasty the procedure is more complicated, as standard devices have to be adapted to different shapes of acetabular defects, which are patient specific especially when they are bigger and wider spread. This kind of big defects, sever acetabular defects, pelvic discontinuity, defects resulted from tumor problems, protrusion, can usually be addressed with a standard Burch-Schneider Antiprotrusio Cage or a Mueller Ring in order to restore the mechanics and the true center of the hip. This paper proposes a design process and manufacturing preparation for a patient specific acetabular cage. The design is intended to fix problems that standard cages sometimes do not resolve, for example insufficient fixation due to the fact that the inferior flange did not engage the ischium, problems of bone graft resorption and in the same time tries to remain an affordable solution. The design process uses as input information the 3D reconstruction of the patient hip from CT scan. Important parameters like the position of the true center of rotation, acetabular anteversion and inclination are determined and calculated. Other parameters, such as number of fixing screws and their designated holes or the amount of bone to be covered with the custom acetabular cage (fixation surface), are proposed by orthopaedic specialist. The design methodology relays on commercial software, such as Solid Works for CAD, 3D Doctor for 3D bone reconstruction from the CT scans or other software for different file transformations. The model was optimized to be produced through direct metal laser-sintering (DMLS). Regarding the results, the particular implant was designed and optimized for fabrication and it is available to be produced. During the design process, although a systematized process was undertaken and implemented, some activities could not be done in systematic, repeatable way. Nevertheless, a design process strategy was established, so that the design would match the requirements of such implant and also a requirements list for the type and form of information needed for this kind of design. Also, we concluded that using software to automate some of the operations that were done manually by the operator would help decrees the design time and improve the repeatability of the process.

Autologous Ilium Grafts: Long‐Term Results on Immediate or Staged Functional Rehabilitation of Mandibular Segmental Defects Using Dental Implants after Tumor Resection

It is a challenge for clinicians to restore oral function in patients with segmental defects of the mandible because of tumor extirpation. Dental implant therapy following vascularized autologous ilium grafts is an effective method to restore oral function in patients with mandibular segmental defects. The aim of this retrospective study was to investigate the long-term clinical outcomes of ilium grafts combined with immediate or staged mandibular dental implant therapy to restore craniofacial defects resulting from tumor resection. Over a 5-year period (2000-2004), 32 patients who underwent mandibular segmental resection for tumors were treated with vascularized ilium grafts to augment bone volume. Seventeen patients received phase I therapy (immediate placement of implants), and 15 patients underwent phase II therapy (delayed placement of implants). A total of 110 dental implants were placed in these patients for mandibular restoration of the defective areas. Information regarding implant success and survival rates, marginal bone loss, soft tissue inflammation, complications of prosthesis, and patient satisfaction for the 8 to 12 years following oral reconstruction was obtained from patient records. Although there was mild evidence of bone graft resorption, the vascularized autogenous ilium bone grafts were successful in all patients. The cumulative patient survival and success rate of the implants were 96.4% and 91.8%, respectively. The mean peri-implant bone resorption ranged from 1.0 to 1.2 mm over the 8- to 12-year follow-up period. The annual mean number of complications/repairs was from 0.11 to 0.07 per patient during the 8- to 12-year follow-up. Over 80% of the patients were fully satisfied with their restoration of oral function. This study demonstrates that reconstruction of mandibular segmental defects because of resection of mandibular tumors using dental implants therapy combined with vascularized autogenous ilium grafts is an effective method to restore oral function.