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

Double layer graft technique for horizontal alveolar ridge augmentation with staged implant placement: radiographic histological and implant stability analysis-a case report

INTRODUCTION

Horizontal ridge augmentation of a deficient alveolar bone site is performed either simultaneously with implant placement or in a staged approach prior to implant insertion. There are several available strategies for the augmentation of alveolar ridge deficiencies, including guided bone regeneration (GBR) through the use of barrier membranes. The success of the GBR approach mainly depends on the exclusion of soft tissue cells during bone remodeling.

CASE PRESENTATION

A healthy 25-year-old male patient presented with a missing upper left central incisor after clinical and radiographic examination, the site showed a class III defect horizontal atrophy. The procedure performed was the horizontal alveolar ridge augmentation using resorbable pericardium membrane with double layer graft technique (DLT) where autogenous bone placed as a first layer of the graft followed by xenograft as a second layer, the membrane was fixed with titanium pins. A cone beam computed tomography (CBCT) was performed before, immediately and 6 month following the surgery. After 6 months during implant placement, a core biopsy specimen was retrieved, stored and prepared for histological evaluation, with assessment of primary implant stability. The radiographic analysis showed a horizontal width gain of about 4 mm, at 6 month following implant placement, the implant was successfully osteointegrated with stability assessment also done after 6 months from placement.

CONCLUSION

DLT was successfully used for horizontal alveolar ridge augmentation, thus allowing a prosthetically driven implant placement. More cases assessing implant survival and success are needed to confirm the results of this case report.

Comparison of vertical bone resorption following various types of autologous block bone grafts

BACKGROUND

This study aims to measure and compare the differences in vertical bone resorption after vertical augmentation using different types of autologous block bone.

METHODS

Data were collected from 38 patients who had undergone vertical ridge augmentation using an autologous block bone before implant insertion. The patients were divided into three groups based on the donor sites: ramus bone (RB), chin bone (CB), and iliac crestal bone (IB).

RESULTS

The surgical outcome of the augmentation was evaluated at the follow-up periods up to 60 months. In 38 patients, the mean amount of vertical bone gain was 8.36 ± 1.51 mm in the IB group, followed by the RB group (4.17 ± 1.31 mm) and the CB group (3.44 ± 1.08 mm). There is a significant difference in vertical bone resorption between the groups (p < 0.001), and the RB group demonstrated significantly lower resorption than the CB and IB groups (p = 0.011 and p < 0.001, respectively). The most common postoperative complications included neurosensory disturbance in the CB graft and gait disturbance in the IB graft. Out of the 92 implants inserted after augmentation, four implants were lost during the study period, resulting in an implant success rate of 95.65%.

CONCLUSIONS

The RB graft might be the most suitable option for vertical augmentation in terms of maintaining postoperative vertical height and reducing morbidity, although the initial gain was greater with the IB graft compared to other block bones.

Regeneration of Horizontal Bone Defect in Edentulous Maxilla Using the Allogenic Bone-Plate Shell Technique and a Composite Bone Graft—A Case Report

An insufficient volume of the alveolar bone may prevent implants from being placed in the prosthetically optimal position. Complex restoration of bony structures is required to achieve long-term peri-implant bone stability and represents an adequate prosthetic solution. Background and Objectives: The shell technique has become a widespread and important method for guided bone regeneration in dentistry. Allogeneic bone materials appear to be the most similar substitution for autogenous bone transplants. However, there are few studies using cortical bone allografts in combination with a mix of autogenous and xenograft materials for the augmentation of horizontal ridge defects. This combination offers the advantage of reduced patient morbidity while adding adequate volume and contour to the alveolar ridge. Case report: The present case study aimed to clinically and radiographically evaluate the efficacy of allogenic cortical bone lamina combined with a composite bone graft in the augmentation of a horizontal bone defect in the edentulous maxilla during a 6-year follow-up period. Three CB CT scans taken before treatment, 6 months after the augmentation period/before implant placement, and after a 6-year follow-up period, were analyzed using stable referent points. After the 6 -year follow-up period, the average resorption rate was 21.65% on the augmented buccal side, with no implant exposure being observed. Conclusions: The bone shell technique used in conjunction with allogenic bone plates combined with autogenous bone, xenografts, and collagen membranes is an effective technique to manage horizontal ridge defects.

Radiographic Evaluation of Bone Remodeling after Additively Manufactured Subperiosteal Jaw Implantation (AMSJI) in the Maxilla: A One-Year Follow-Up Study

Additively manufactured subperiosteal jaw implants (AMSJI) are patient-specific, 3D-printed, titanium implants that provide an alternative solution for patients with severe maxillary bone atrophy. The aim of this study was to evaluate the bony remodeling of the maxillary crest and supporting bone using AMSJI. Fifteen patients with a Cawood–Howell Class V or greater degree of maxillary atrophy were evaluated using (cone beam) computed tomography scans at set intervals: one month (T1) and twelve months (T2) after definitive masticatory loading of bilateral AMSJI implants in the maxilla. The postoperative images were segmented and superimposed on the preoperative images. Fixed evaluation points were determined in advance, and surface comparison was carried out to calculate and visualize the effects of AMSJI^TM on the surrounding bone. A total mean negative bone remodeling of 0.26 mm (SD 0.65 mm) was seen over six reference points on the crest. Minor bone loss (mean 0.088 mm resorption, SD 0.29 mm) was seen at the supporting bone at the wings and basal frame. We conclude that reconstruction of the severely atrophic maxilla with the AMSJI results in minimal effect on supporting bone. Reduced stress shielding with a biomechanically tuned subperiosteal implant does not induce radiographically significant crestal bone atrophy.

Bone-Graft Resorption Reduced by the Induced Membrane Technique and Factors Affecting Volumetric Changes: An Analysis of 120 Serial Computed Tomographic Scans in 40 Patients

BACKGROUND

Little is known about the volumetric changes of grafted bone over time when using the induced membrane technique. This study investigates the volumetric changes of bone graft using serial computed tomographic (CT) scans following the induced membrane technique.

METHODS

Patients with critical-sized bone defects had serial CT scans after undergoing bone-grafting using the induced membrane technique. CT scans to evaluate the volume of bone graft were obtained immediately postoperatively and at 6 and 12 months. The change in the volume of bone graft was determined at 6 and 12 months postoperatively. Patient demographic characteristics, the location and composition of the bone graft, and the type of fixation construct were analyzed.

RESULTS

Forty patients met inclusion criteria. There were 27 tibiae and 13 femora with a mean size defect of 8.6 cm (range, 2.5 to 20.6 cm). Of these patients, 21 received autograft with cancellous bone graft and 19 received mixed autogenous bone with demineralized bone matrix (DBM) at a mean time of 17 weeks after the membrane formation. For the first 6 months, there was an overall osseous resorption of -9.9%. The overall graft volume from 6 to 12 months demonstrated an increase of osseous volume by +1.6%. For the entire 12-month period, there was a mean graft volume resorption of -8.3%. A correlation was found between the early volumetric changes of grafted bone and the percentage of DBM in the graft mixture. A correlation was also found between the late volumetric changes and the location of defect or the type of fixation.

CONCLUSIONS

At 1 year after use of the induced membrane technique for the treatment of a critical-sized bone defect, resorption of the grafted bone averaged -8.3%. The volumetric changes were influenced by the property of the grafted bone, the fixation construct, and the location of the defect.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Assessment of clinical outcomes and histomorphometric findings in alveolar ridge augmentation procedures with allogeneic bone block grafts: A systematic review and meta-analysis

BACKGROUND

This systematic literature review aimed to evaluate the efficacy of allogeneic bone blocks for ridge augmentation by assessing block survival rates and subsequent implant survival, including post-surgical complications and histomorphometric analysis.

MATERIAL AND METHODS

An electronic and manual search among references, was conducted up to April 2019 by two independent authors. Inclusion criteria were: human clinical trials in which the outcomes of allogeneic bone block grafts were evaluated by means of their survival rates and subsequent implant success rates.

RESULTS

Seven articles fulfilled the inclusion criteria and were analyzed. A total of 323 allogeneic block grafts were monitored for a minimum of 12 months follow-up after surgery, of which thirteen (4.02%) failed. Regarding the cumulative implant survival rate, the weighted mean was 97.36%, computed from 501 implants. Histologic and histomorphometric analysis showed that allogeneic block grafts presented some clinical and microstructural differences in comparison with autologous block grafts.

CONCLUSIONS

Atrophic alveolar crest reconstruction with allogeneic bone block grafts would appear a feasible alternative to autologous bone block grafts, obtaining a low block graft failure rate, similar implant survival rate and fewer postoperative complications. Further investigations generating long term data are needed to confirm these findings.

Comparison of in-situ bone ring technique and tent-pole technique for horizontally deficient alveolar ridge in the anterior maxilla

BACKGROUND

Limited studies focused on the bone profile maintenance at the alveolar ridge crest applying horizontal bone augmentation.

PURPOSE

A novel approach named as "in-situ bone ring technique" was introduced to be compared with tent-pole technique to evaluate their horizontal bone gain, resorption, and postoperative perception.

MATERIALS AND METHODS

A total of 30 patients were included in this retrospective cohort study. All patients required horizontal bone augmentation at anterior site. Accordingly, quantitative and qualitative analyses were conduct radiographically and histologically between in-situ bone ring (ring group) and tent-pole technique (tent group). Moreover, the visual analog scale (VAS) was introduced to assess the patients' perception toward both treatments.

RESULTS

Cone-beam computed tomography results showed great significant difference regarding horizontal bone width at 0 mm and 3 mm from alveolar ridge crest between two groups (P < .05). On the basis of histological outcomes, delightful bony fusion was shown 6-month postoperatively in ring group. The VAS ratings for pain and swelling reflected similar results between two groups.

CONCLUSIONS

In-situ bone ring technique evidently increased and maintained horizontal bone mass at the alveolar ridge crest compared to tent-pole technique, which might be favorable for implant rehabilitation in anterior area. Meanwhile, no further discomfort was caused according to VAS scoring between two groups.

Cell therapy induced regeneration of severely atrophied mandibular bone in a clinical trial

Background

Autologous grafting, despite some disadvantages, is still considered the gold standard for reconstruction of maxillofacial bone defects. The aim of this study was to evaluate bone regeneration using bone marrow-derived mesenchymal stromal cells (MSCs) in a clinical trial, a less invasive approach than autologous bone grafting. This comprehensive clinical trial included subjects with severe mandibular ridge resorption.

Methods

The study included 11 subjects aged 52–79 years with severe mandibular ridge resorption. Bone marrow cells were aspirated from the posterior iliac crest and plastic adherent cells were expanded in culture medium containing human platelet lysate. The MSCs and biphasic calcium phosphate granules as scaffolds were inserted subperiosteally onto the resorbed alveolar ridge. After 4–6 months of healing, new bone formation was assessed clinically and radiographically, as were safety and feasibility. Bone at the implant site was biopsied for micro-computed topography and histological analyses and dental implants were placed in the newly regenerated bone. Functional outcomes and patient satisfaction were assessed after 12 months.

Results

The bone marrow cells, expanded in vitro and inserted into the defect together with biphasic calcium phosphate granules, induced significant new bone formation. The regenerated bone volume was adequate for dental implant installation. Healing was uneventful, without adverse events. The patients were satisfied with the esthetic and functional outcomes. No side effects were observed.

Conclusions

The results of this comprehensive clinical trial in human subjects confirm that MSCs can successfully induce significant formation of new bone, with no untoward sequelae. Hence, this novel augmentation procedure warrants further investigation and may form the basis of a valid treatment protocol, challenging the current gold standard.

Trial registration

EudraCT, 2012-003139-50. Registered on 21 August 2013. ClinicalTrials.gov, NCT 02751125. Registered on 26 April 2016.

Comparison of Bone Resorption Rates after Intraoral Block Bone and Guided Bone Regeneration Augmentation for the Reconstruction of Horizontally Deficient Maxillary Alveolar Ridges

Purpose. Bone atrophy after tooth loss may leave insufficient bone for implant placement. We compared volumetric changes after autogenous ramus block bone grafting (RBG) or guided bone regeneration (GBR) in horizontally deficient maxilla before implant placement. Materials and Methods. In this retrospective study, volumetric changes at RBG or GBR graft sites were evaluated using cone-beam computed tomography. The primary outcome variable was the volumetric resorption rate. Secondary outcomes were bone gain, graft success, and implant insertion torque. Results. Twenty-four patients (28 grafted sites) were included (GBR, 15; RBG, 13). One patient (RBG) suffered mucosal dehiscence at the recipient site 6 weeks after surgery, which healed spontaneously. Mean volume reduction in the GBR and RBG groups was 12.48 ± 2.67% and 7.20 ± 1.40%, respectively. GBR resulted in significantly more bone resorption than RBG (P < 0.001). Mean horizontal bone gain and width after healing were significantly greater in the GBR than in the RBG group (P = 0.002 and 0.005, resp.). Implant torque was similar between groups (P > 0.05). Conclusions. Both RBG and GBR hard-tissue augmentation techniques provide adequate bone graft volume and stability for implant insertion. However, GBR causes greater resorption at maxillary augmented sites than RBG, which clinicians should consider during treatment planning.

Evaluation of the autogenous bone block transfer for dental implant placement: Symphysal or ramus harvesting?

Background

The absence of sufficient bone volume is the most relevant problem in implant dentistry. Grafting from exogenous sources may provide a limited gain but exhibits poor performance in large bone defects. Autogenous bone block transfer (ABBT) from the mandibular symphysis and ramus has been used with varying rates of success. The aim of this study was to compare the efficacy of symphysal and ramus ABBT for the restoration of lost horizontal alveolar bone volume in the anterior maxilla. Implants placed in the augmented areas were also evaluated.

Methods

The maxillary alveolar bone deficits of 32 patients were treated by similar-sized autogenous bone blocks (7 × 7 × 4 mm) harvested from the symphysis or ramus area. After 4 to 5 months of healing, implants were inserted. At the end of the osseointegration period, the implants were restored by fixed prostheses. Baseline bone thickness was determined by Cone beam computed tomography and was compared to post-op and one-year post-loading bone thickness values where the implants were inserted. Any complications or consequences were noted. The success and survival of the 45 implants were evaluated. The results were analyzed using the Student t-test and Fisher’s exact test (p < 0.05).

Results

Post-op complications were frequent in both groups. Baseline bone thickness values were similar at the beginning of the study (p = 0.71) and exhibited a significant increase after the ABBT surgery (6.29 (SD 0.86) and 6.01 (SD 0.92) mm in the symphysis and ramus groups, respectively). The amount of bone thickness gain was 4.34 mm (SD: 0.92) and 4.36 mm (SD: 1.01) in the symphysis and ramus groups, respectively. After one year, the mean surface resorption was 0.6 mm (SD: 0.78) and 0.80 mm (SD: 0.56) for the symphysis and ramus groups, respectively (p = 0.089). The success and survival rates of the implants were 94.11 and 96.42 %, respectively. No graft failures were observed.

Conclusions

Both symphysal and ramus ABBT procedures were successful for the restoration of a horizontal bone defect in the anterior maxilla. Ramus harvesting may be advisable due to fewer complications. Implants placed in the grafted regions exhibited a high success and survival rate within the one-year follow-up period.