Efficacy and volume stability of a customized allogeneic bone block for the reconstruction of advanced alveolar ridge deficiencies at the anterior maxillary region: a retrospective radiographic evaluation.

OBJECTIVES: The aim of this retrospective case series was to evaluate the efficacy and volume stability of a customized allogeneic bone block (CABB) for the hard tissue reconstruction of severely atrophied anterior maxillary ridges. MATERIALS AND METHODS: Hard tissue alterations between baseline (T1), 2-month follow-up (T2), and 6-month follow-up (T3) cone-beam computed tomography scans were evaluated with semi-automatic segmentation. Following automatic spatial alignment of the datasets, 3D subtraction analysis was performed. The volume stability of the inserted allogeneic bone block was determined on the basis of the ratio of the T3 and T2 hard tissue volumes. RESULTS: The newly formed hard tissue volume at T2 averaged at of 0.75 cm3 ± 0.57 cm3, whereas at T3, an average of 0.52 cm3 ± 0.42 cm3 volumetric hard tissue gain could be detected. The T3/T2 ratio was found to be 67.83% ± 18.72% on average. The dice similarity coefficient between the T2 and T3 hard tissue models averaged at 0.73 ± 0.15. CONCLUSIONS: Cancellous CABBs are a reliable option for the reconstruction of severely atrophied alveolar ridges. The resorption rates of these grafts are similar to those found in the literature; however, with precise manufacturing and proper intraoperative flap management, the resorption rates may be reduced. CLINICAL RELEVANCE: With precise knowledge of the resorption patterns, the shape of blocks can be altered in the future to compensate for the volumetric loss.

A customized allogenic bone block for alveolar reconstruction quantitated by a 3D matching technique: A case report.

After initial resorption, the bone volume showed long-term stability following loading of the implant. Furthermore, 3D matching was a suitable quantification method to analyze the volume development of bone augmentation.

Influence of Clinical Parameters on the Primary Stability of a Tapered Dental Implant: A Retrospective Analysis.

PURPOSE: The aim of this study was to investigate the influence of different clinical parameters on the primary stability of a variable thread tapered implant system with a focus on surgical undersizing protocols. MATERIALS AND METHODS: This retrospective study evaluated patients who received NobelActive implants in a single institution. The relationship between the independent variables, bone quality, implant diameter, implant length, implantation time, region of the jaw, and surgical undersizing protocol, and the dependent variable, maximum insertion torque, was investigated. Statistical analysis was conducted using analysis of variance (ANOVA) and multiple linear regression. RESULTS: A total of 1,292 implants placed in 574 fully or partially edentulous patients were evaluated. For the total sample size, without further differentiation between bone qualities, statistically significantly higher primary stability values were shown for an 8% to 9% undersized group (50.33 ± 17.16 Ncm), compared with a 16% undersized group (41.88 ± 17.63 Ncm), a 20% undersized group (33.65 ± 15.78 Ncm), a 26% to 28% undersized group (34.53 ± 15.49 Ncm), and a 35% to 44% undersized group (32.78 ± 18.80 Ncm). No statistical differences were found for undersizing protocols in bone quality 4. Bone quality had the highest influence on primary stability (Welch-Test F(3, 65.57) = 119.48, P < .001, η2 = .20). Contrary to the other investigated independent variables, no statistically significant differences in primary stability were found for the different implantation times. CONCLUSION: Undersizing protocols exceeding 8% to 9% do not seem to enhance primary stability values. Further studies are needed to investigate the biologic consequences of undersizing, including the impact of implant design characteristics.

Volumetric Changes of a Customized Allogeneic Bone Block Measured by Two Image Matching Tools: Introduction of a Novel Assessment Technique for Graft Resorption.

OBJECTIVE: The purpose of this case report was to present a method for the assessment of volumetric changes of bone blocks during healing and demonstrate its practicability by analysing the resorption of a pre-shaped allogeneic bone block used for the reconstruction of a complex maxillary defect. MATERIALS AND METHODS: CBCT-scans of a 19-year-old male treated with an allogeneic bone block were recorded pre-OP, post-OP, and following six months of healing. Graft shrinkage was assessed via two image matching tools, namely coDiagnostiX® and Slicer. A biopsy specimen was harvested along the implant canal at the time of implantation. RESULTS: The osseous defect was successfully restored and advanced graft remodelling was found upon re-entry as confirmed by the histomorphometric and histologic analysis. The initial volumes of the graft determined via coDiagnostiX® and Slicer were 0.373 mL and 0.370 mL., respectively, while graft resorption after six months of healing was 0.011 mL (3.00%) and 0.016 mL (4.33%). CONCLUSIONS: The avoidance of bone harvesting and reduction of invasiveness display an important issue in dentoalveolar restorations. However, before grafting materials can be considered a safe alternative, understanding their clinical performance, especially resorption stability, is pivotal. The present case report demonstrates a limited resorption of the allogeneic bone block and further emphasizes the practicability of determining bone resorption by the here introduced method. As our investigation comprises solely one subject, the results should be considered with care and substantiated by further studies.

Long-Term Efficacy of Variable-Thread Tapered Implants-A Retrospective, Clinical and Radiological Evaluation.

Background and Objective: There is multifaceted evidence that variable-thread tapered implants (VTTIs) offer high primary stability but few regarding the long-term success. This retrospective clinical and radiological cohort study assessed the long-term outcome of VTTIs. Material and Methods: All patients treated in an OMFS practice with NobelActive Internal® VTTI between October 2007 and September 2011 were invited for clinical examination. The outcome variables were (i) survival rate, (ii) implant success according to the "Health Scale for Dental Implants" and (iii) prevalence of peri-implantitis. Furthermore, the effect of local and systemic risk factors was investigated. Results: In 81 subjects (46 females and 35 males, mean age 65.6 years) 270 implants (157 VTTIs and 113 others as a control group) were analyzed. In 7 out of 81 patients (8.6%), 8 out of 157 VTTIs (5.1%) and 5 out of 113 other implants (4.4%) were lost. Peri-implantitis, defined as (i) presence of bleeding on gentle probing (0.25 N) or exudation and (ii) radiographic bone loss exceeding 0.5 mm since implant insertion to last follow-up, was the most common reason for implant loss (11 out of 13, 84.6%). Sixty-six out of 87 VTTIs (75.9%) were successful. Seventeen out of 42 patients (40.5%) developed peri-implantitis on 29 out of 79 VTTI sites (36.7%). Plaque and missing keratinized peri-implant mucosa were identified as potential risk factors for the development of peri-implantitis. Conclusion: Variable-thread tapered implants showed good long-term results, even in low bone quality. Peri-implantitis was the most common reason for implant failure and may be connected to certain risk factors.

Reconstruction of a Unilateral Alveolar Cleft Using a Customized Allogenic Bone Block and Subsequent Dental Implant Placement in an Adult Patient.

Cleft lip and palate is the most common congenital deformity with severe effects on the quality of life of affected patients. The deformity often includes an alveolar cleft (AC). In most cases, osteoplasty will be performed using autogenous bone transplants harvested from the iliac crest. Thus, this treatment represents a highly invasive procedure. With freeze-dried bone allografts (FDBAs) becoming an increasingly accepted alternative to autogenous bone grafting for several indications, their application might also be suitable for AC reconstruction. We present the use of a customized allogenic bone block in a guided bone regeneration procedure for reconstruction of a unilateral AC and the successful insertion of dental implants after a healing period of 6 months. The use of FDBA seems to represent a successful treatment option for AC reconstruction. The allogenic bone block demonstrated high volume stability with ideal integration and revascularization, resulting in functional bone tissue suitable for implantation and esthetic rehabilitation. Nevertheless, further investigations, especially concerning the long-term stability of the augmented bone and dental implants, are needed to draw definite conclusion regarding the performance of allogenic bone blocks in orofacial cleft osteoplasty.

Bilateral maxillary augmentation using CAD/CAM manufactured allogenic bone blocks for restoration of congenitally missing teeth: A case report.

OBJECTIVE: Various biomaterials have been successfully applied in alveolar bone regeneration, however, the reconstruction of extensive osseous defects remains challenging and is often unfeasible with granular grafting materials. Several studies have outlined allogenic bone blocks as valid alternative to autologous block grafting. CLINICAL CONSIDERATIONS: In this report, we demonstrate the regeneration of two large osseous defects in the maxilla with allogenic bone blocks made from human donor bone. The bone blocks were customized using the CAD/CAM technology in order to enable the insertion of four dental implants. CONCLUSIONS: Both blocks perfectly matched the defect geometry, showed limited resorption, led to the formation of sufficient amounts of mineralized bone in both horizontal and vertical dimensions and enabled the installation of implants according to the treatment plan. The implementation of innovative technologies for individualization of allogenic bone blocks simplifies the restoration of complex and extensive osseous defects and poses great benefits for both practitioners and patients. CLINICAL SIGNIFICANCE: The here presented procedure demonstrates the successful regeneration of two extensive osseous defects in a patient suffering from hypodontia using two CAD/CAM manufactured allogenic bone blocks, rendering the procedure far less invasive as compared to guided bone regeneration carried out with autologous transplants. Furthermore, to the best of our knowledge, this is the first case report that radiographically demonstrates the new formation of a cortical bone layer following block grafting with solely cancellous bone blocks.

Treatment of a bilaterally severely resorbed posterior mandible due to early tooth loss by Guided Bone Regeneration using customized allogeneic bone blocks: A case report with 24 months follow-up data.

OBJECTIVE: The use of allogeneic bone grafts for alveolar ridge reconstruction has become an often-discussed alternative to augmentation procedures using autografts. Nevertheless, there still is a lack of literature concerning long-time experiences of allografts for alveolar ridge reconstruction. Especially the results of the use of allogeneic bone blocks for mandible reconstructions need to be further investigated. CLINICAL CONSIDERATIONS: In this case report, we present the use of customized allogenic bone blocks in Guided Bone Regeneration (GBR) procedures for severely deficient mandibulary bones, the implantation after a healing period of 5 month and the 24-month follow-up data. CONCLUSIONS: Customized allogeneic bone blocks seem to be a successful alternative to augmentations with autologous bone blocks reconstructing highly resorbed mandibulary alveolar ridges, showing highest volume stability and no signs of bone resorption after implant loading. CLINICAL SIGNIFICANCE: The application of customized allogeneic bone blocks has shown to be a successful augmentation technique even compared with with autologous bone blocks reconstructing highly resorbed mandibulary alveolar ridges demonstrating no compromises regarding clinical outcome, functionality and esthetics.

Treatment of Severely Resorbed Maxilla Due to Peri-Implantitis by Guided Bone Regeneration Using a Customized Allogenic Bone Block: A Case Report.

The objective of this case report is to introduce a customized CAD/CAM freeze-dried bone allograft (FDBA) block for its use in Guided Bone Regeneration (GBR) procedures for severely deficient maxillary bones. Additionally, a special newly developed remote incision technique is presented to avoid wound dehiscence. The results show optimal integration behavior of the FDBA block after six months and the formation of new vital bone. Thus, the results of the present case report confirm the use of the customized CAD/CAM bone block for augmentation of complex defects in the maxillary aesthetic zone as a successful treatment concept.