Survival rate of osseointegrated implants in atrophic maxillae grafted with calvarial bone: a retrospective study

Long-term survival and success rate of dental implants placed in reconstructed areas with extraoral autogenous bone grafts: A systematic review and meta-analysis

OBJECTIVE

To evaluate the long-term survival and success rates of implants placed in reconstructed areas using microvascularized or non-microvascularized extraoral bone grafts.

MATERIALS AND METHODS

An electronic search was performed in five databases and in gray literature for articles published until June, 2023. The eligibility criteria comprised observational studies (prospective or retrospective) and clinical trials, reporting survival and success rates of implants placed in extraoral bone grafts. A meta-analysis (implant failure) was categorized into subgroups based on the type of bone graft used. The risk of bias within studies was assessed using the Newcastle-Ottawa Scale.

RESULTS

Thirty-one studies met the inclusion criteria. The mean follow-up time was 92 months. The summary estimate of survival rate at the implant level were 94.9% (CI: 90.1%-97.4%) for non-vascularized iliac graft, 96.5% (CI: 91.4%-98.6%) for non-vascularized calvaria graft, and 92.3% (CI: 89.1%-94.6%) for vascularized fibula graft. The mean success rate and marginal bone loss (MBL) were 83.2%; 2.25 mm, 92.2%; 0.93 mm, and 87.6%; 1.49 mm, respectively.

CONCLUSIONS

Implants placed in areas reconstructed using extraoral autogenous bone graft have high long-term survival rates and low long-term MBLs. The data did not demonstrate clinically relevant differences in the survival, success, or MBL of grafts from different donor areas or with different vascularization. This systematic review was registered in INPLASY under number INPLASY202390004.

Maxillary bone augmentation with calvarial bone graft for immediate full-arch rehabilitation: Insights from a 10-year proof-of-concept retrospective analysis

OBJECTIVE

Evaluate the long-term outcomes of full-arch rehabilitation using immediate dental implant placement and continuous functional loading with full-fixed dental prostheses (FFDPs).

MATERIALS AND METHODS

Fifty-six patients received temporary implants (n = 327) at maxillary augmentation with calvarial bone. A provisional acrylic FFDP was immediately loaded onto these implants. After 6 months, the temporary implants were replaced with definitive implants (n = 326) and immediately loaded with a second provisional FFDP (N = 55). Subsequently, a baseline radiograph was taken following a 6-month healing period. The second bridge was then substituted with a definitive FFDP. Primary outcomes included peri-implant marginal bone level (MBL) and definitive implant survival. Secondary outcomes evaluated provisional implant and prostheses survival, complications, and patient satisfaction.

RESULTS

The provisional implants had a survival rate of 97.9%. One patient was excluded from further analysis due to loss of temporary implants and first FFDP. The definitive implant survival rate after 10 years was 92.2%, with a moderate but significant decrease in MBL between baseline radiography and 10 years later (-0.08 ± 0.18 vs. -0.24 ± 0.44). However, large individual variations were observed, with 65.8% of implants showing no bone loss and 9.2% showing loss ≥0.5 mm. Sinusitis was experienced by 14.3% of patients upon surgery. Patient satisfaction was high or reported no issues after protocol completion (80%). One patient lost all six definitive implants and definitive FFDP 8.2 years after implant placement.

CONCLUSIONS

The described protocol can be regarded as a long-term, highly successful method for full-arch rehabilitation of atrophied maxillae while enabling continuous masticatory and speaking functionality.

The influence of vertical ridge augmentation techniques on peri-implant bone loss: A systematic review and meta-analysis

INTRODUCTION

The primary aim of this systematic review was to investigate and compare the outcomes of different vertical ridge augmentation (VRA) techniques in relation to peri-implant bone loss (PBL), after at least 12 months of functional loading.

MATERIAL AND METHODS

The search was conducted to find all the studies about VRA and measurements of PBL with at least 12 months follow-up. Three pairwise meta-analysis (MA) was performed to completely evaluate the outcomes.

RESULTS

A total of 42 studies were included, of which 11 were randomized clinical trials (RCTs). RCTs were available only for guided bone regeneration (GBR), onlay, and inlay techniques. The weighted mean estimate (WME) of PBL value was found to be 1.38 mm (95% confidence interval [95% CI]: 1.10-1.66) after a mean follow-up of 41.0 ± 27.8 months. GBR, Inlay, Onlay, osteodistraction, and SBB represented in weight 32.9%, 30.6%, 25.0%, 7.6%, and 3.9%, respectively; and their WME (95% CI) were 1.06 (0.87-1.26) mm, 1.72 (1.00-2.43) mm, 1.31 (0.87-1.75) mm, 1.81 (0.87-1.75) mm, and 0.66 (0.55-0.77) mm, respectively. Among the secondary outcomes, the analysis was conducted for vertical bone gain, healing complication rate, surgical complication rate, implant survival, and success rate.

CONCLUSIONS

The primary findings of the meta-analysis, based on the changes between final and baseline values, showed that the peri-implant bone loss could be influenced by the type of intervention but there is a need to evaluate in RCTs the behavior of the peri-implant bone levels after long-term follow-up for all techniques.

Harvesting anterior iliac crest or calvarial bone grafts to augment severely resorbed edentulous jaws: a systematic review and meta-analysis of patient-reported outcomes

The aim of this systematic review was to compare patient-reported outcomes after harvesting calvarial or anterior iliac crest bone grafts to repair severe jaw defects and enable implant placement. The MEDLINE, Embase, Cochrane Central Register of Controlled Trials databases, and OpenGrey were searched for studies on patient satisfaction, pain, disturbances in daily functioning, sensory alterations, donor site aesthetics, and complication rates. Of the 1946 articles identified, 43 reporting 40 studies fulfilled the inclusion criteria; the studies were one randomized controlled clinical trial, one retrospective controlled clinical trial, and 23 prospective and 15 retrospective cohort studies. A meta-analysis of two studies (74 patients) showed no difference in satisfaction (mean difference (MD) - 0.13, 95% confidence interval (CI) - 1.17 to 0.92; P = 0.813) or postoperative pain (directly postoperative: MD -2.32, 95% CI -5.20 to 0.55, P = 0.113; late postoperative: MD -0.01, 95% CI -0.14 to 0.11, P = 0.825) between donor sites. However, the level of evidence is limited, due to the retrospective, non-randomized design of one study. Postoperative gait disturbances were highly prevalent among the anterior iliac crest patients (28-100% after 1 week). The incidence rates of sensory disturbances and other complications were low, and the donor site aesthetic outcomes were favourable for both graft types. To conclude, harvesting bone grafts from the calvarium or anterior iliac crest to augment the severely resorbed edentulous jaw results in similar patient satisfaction. However, the findings for postoperative pain and disturbances in daily living suggest a trend in favour of calvarial bone grafts if harvested using an adjusted technique.

Digital versus Traditional Workflow for Immediate Loading in Single-Implant Restoration: A Randomized Clinical Trial

The purpose of this randomized controlled trial was to compare the immediate-loading protocol, in single restorations in the esthetic zone, by comparing the digital workflow in a test group (TG) vs. the analogical workflow in a control group (CG). A total of 50 patients were enrolled, requiring single hopeless tooth extraction. Twenty-five patients (TG) were randomly assigned to the immediate-loading protocol using the digital workflow, and twenty-five patients (CG) were assigned to the conventional workflow. Clinical and radiographic parameters were evaluated at the time of implant insertion (baseline) and after 3, 6 and 12 months, respectively. A clinician blind to conditions measured the Pink Esthetic Score (PES), as well as patient satisfaction. At 12-month follow-up, a cumulative survival rate of 100% was reported for all implants. No failures or biological complications were observed. No statistically significant differences were detected in the mean values of marginal bone loss and PES between the TG (0.12 ± 0.66 mm for MBL, 7.75 ± 0.89 for PES) and the CG (0.15 ± 0.54 mm for MBL, 7.50 ± 0.89 for PES). In 11 cases of TG, and 10 cases of CG, a one-year follow-up period showed an increased marginal bone level. No statistically significant differences were found in the mean total PES between test (7.75 ± 0.89) and control (7.5 ± 0.81) conditions. Furthermore, a customer satisfaction survey showed that patients preferred the digital workflow over the conventional workflow procedure (97.6 ± 4.3 vs. 69.2 ± 13.8). Digital workflow was more time-efficient than conventional workflow (97.2 ± 7.3 vs. 81.2 ± 11.3). Within the limitations of this study, no statistically significant differences were found between digital and traditional workflow.

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, 3mm 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 48hours (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 2.36mm (16.87%) in the anterior region, 3.53mm (22.47%) in the medial region, and 2.21mm (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.

Retreatment of multiple failing maxillary implants after full arch rehabilitation: a retrospective, observational cohort study

The aim of this study was to assess implant retreatment in a group of patients whose maxillary implants were all failing after full arch rehabilitation. Treatment involved implant removal, augmentation, and placement of an overdenture supported by four to six implants. All consecutive patients referred between 2008 and 2018, following multiple late implant failures in the rehabilitated maxilla, were included in the study. Seventy implants in 15 patients were evaluated at 3.3 ± 2.5 years (range 1.1-8.6 years) after loading. Implant survival, complications, clinical parameters, marginal bone loss, and patient-related outcome measures were recorded at the time of evaluation. Overall implant survival was 95.7%. Three implant failures occurred within the first year of function. Marginal bone loss was 0.32 ± 0.46 mm; pocket probing depth was 4.55 ± 1.59 mm. Plaque, calculus, inflammation, and bleeding were hardly seen (median index score 0). Patients scored their satisfaction with their overdentures as high (mean overall score 8.7 ± 1.2, maximum 10). Chewing soft and tough food was scored as 'good' and hard food as 'moderate'. The mean Oral Health Impact Profile score was 29.5 ± 33.3. It can be concluded that the replacement of multiple failing implants in an edentulous maxilla after bone augmentation is a safe and predictable treatment procedure when applied as an implant-supported overdenture.

Analysis of the Survival of Dental Implants Installed in Reconstructed Maxilla with Autogenous Iliac Crest Graft: 7- to 9-Year Follow-Up

The aim of this study was to analyze the survival of dental implants installed in maxillae reconstructed with autogenous iliac crest grafts and to assess patient satisfaction with the treatment by means of a questionnaire. The study conducted medical record reviews and clinical/radiographic assessments of 10 patients with severe maxillary atrophy who had undergone reconstruction with autogenous iliac crest grafts and rehabilitation with dental implants between 2008 and 2011. Patients were assessed for the survival of the implants, considering implant diameter and length, smoking status, diagnosis of diabetes, type of loss, and region of implant loss. In addition, a questionnaire with specific questions on the patients' satisfaction with the treatment was administered. Seventy-six implants were installed in the sampled patients, and only 1 loss was observed (late loss in the anterior maxilla region) after an average follow-up of 7.9 years, which corresponds to a 98.60% survival rate. The installed implants were of the most frequently used dimension (3.75 × 10 mm). One sampled patient was diabetic, and a second patient was both diabetic and a smoker. No loss of implants was observed in these 2 patients. All patients reported being completely satisfied with the treatment and would undergo the procedure again or refer it to a friend/relative. Six patients reported regular maintenance of the prosthesis, and only 3 had changed the prosthesis prior to the time of questionnaire administration. The results of this limited study with a restricted sample population suggest that the reconstruction of the maxilla with an autogenous iliac crest graft provides both adequate implant survival and patient satisfaction.

Remodeling of calvarial graft in increased atrophic maxillary thickness. A prospective clinical study

PURPOSE

This study evaluated the autogenous graft resorption rate in a calvarial block graft in the anterior region of an atrophic maxilla and compared it with the thickness of the remaining ridge.

MATERIALS AND METHODS

Twelve patients were included in the study. They were submitted to cranial calotte graft surgery, and there were 40 blocks in total. The thicknesses of the ridges in the crest, middle and apical regions of the blocks were evaluated by computed tomography scan at the times: preoperative (T0), 48 hours (T1) and 6 months (T2) after the reconstructions.

RESULTS

The resorption of the blocks from T1 to T2 was 13.4%. The greatest remodeling occurred in the alveolar bone crest (20.07%), followed by the middle portion (12.28%), and the apical region (9.5%), but the three regions did not significantly differ between times T1 and T2 (crest P = .07, middle P = .124, apical P = .131). Recipient site with the lowest thickness had the greatest resorption rates (up to 2 mm = 17.6%; from 2 to 4 mm = 17.52%) while than those with a thickness greater than 4 mm had a mean resorption of 8.81%.

CONCLUSIONS

The resorption of the grafts in this study was 13.4%. Higher resorption rates were observed in the alveolar crest areas, where the ridges were less thick.

Use of homologous bone for alveolar crest reconstruction in 483 patients with 5 years' outcomes post implantation

PURPOSE

The purpose of this study was to evaluate the clinical course of bone reconstruction of the alveolar crest using homologous fresh-frozen bone harvested from deceased donors.

METHODS

A retrospective survey was based on the Castelfranco Veneto Hospital database, in which 3264 clinical records with a primary or secondary diagnosis of alveolar atrophy were collected over a 10-year period. A random sample of 483 patients with at least 5 years' follow-up was included in the survey. Patients were contacted by telephone and administered a questionnaire with specific questions to build a significant sample.

RESULTS

Of the patients, 449 (93% of the sample) had an uneventful follow-up after surgery and 93.2% received at least one implant, with a mean of 3.4 implants per patient. At the time of the survey, 93% of the patients were wearing a dental prosthesis, 86.9% had not lost any implants, and 6.7% had lost at least one implant, while 6.4% still had implants but presented some clinical problems. Finally, patients were asked to provide an index score (1-10 points) on the therapy as a whole, i.e., bone graft, implants, and prostheses. A score of insufficient (up to 5 points) was given by 5.3% of patients, of sufficient (6 to 7 points) by 6.1%, and of good/very good (over 7) by 88.6%.

CONCLUSIONS

Homologous bone for alveolar crest reconstruction can be a valid alternative to autologous grafting if specific tissue limitations are considered when planning therapy. Creeping substitution is partial and slower than in autologous grafts, especially in cases where cortical bone is thick or volume graft is very large. The quality of soft tissue coverage and mucosa lining is also important, possibly due to slower tissue revascularization, so future implants should predictably be positioned primarily within the original host bone.

Use of homologous bone for alveolar crest reconstruction in 483 patients with 5 years' outcomes post implantation

Purpose

The purpose of this study was to evaluate the clinical course of bone reconstruction of the alveolar crest using homologous fresh-frozen bone harvested from deceased donors.

Methods

A retrospective survey was based on the Castelfranco Veneto Hospital database, in which 3264 clinical records with a primary or secondary diagnosis of alveolar atrophy were collected over a 10-year period. A random sample of 483 patients with at least 5 years’ follow-up was included in the survey. Patients were contacted by telephone and administered a questionnaire with specific questions to build a significant sample.

Results

Of the patients, 449 (93% of the sample) had an uneventful follow-up after surgery and 93.2% received at least one implant, with a mean of 3.4 implants per patient. At the time of the survey, 93% of the patients were wearing a dental prosthesis, 86.9% had not lost any implants, and 6.7% had lost at least one implant, while 6.4% still had implants but presented some clinical problems. Finally, patients were asked to provide an index score (1–10 points) on the therapy as a whole, i.e., bone graft, implants, and prostheses. A score of insufficient (up to 5 points) was given by 5.3% of patients, of sufficient (6 to 7 points) by 6.1%, and of good/very good (over 7) by 88.6%.

Conclusions

Homologous bone for alveolar crest reconstruction can be a valid alternative to autologous grafting if specific tissue limitations are considered when planning therapy. Creeping substitution is partial and slower than in autologous grafts, especially in cases where cortical bone is thick or volume graft is very large. The quality of soft tissue coverage and mucosa lining is also important, possibly due to slower tissue revascularization, so future implants should predictably be positioned primarily within the original host bone.

Critical Defect Healing Assessment in Rat Calvaria Filled with Injectable Calcium Phosphate Cement

(1) Background: The tissue engineering field has been working to find biomaterials that mimic the biological properties of autogenous bone grafts. (2) Aim: To evaluate the osteoconduction potential of injectable calcium phosphate cement implanted in critical defects in rat calvaria. (3) Methods: In the calvarial bone of 36 rats, 7-mm diameter critical size defects were performed. Afterwards, the animals were randomly divided into three groups according to filler material: a blood clot group (BC), blood clot membrane group (BCM), and an injectable β-tricalcium phosphate group (HBS) cement group. After periods of 30 and 60 days, the animals were euthanized, the calvaria was isolated, and submitted to a decalcification process for later blades confection. Qualitative and quantitative analysis of the neoformed bone tissue were conducted, and histometric data were statistically analyzed. (4) Results: Sixty days post-surgery, the percentages of neoformed bone were 10.67 ± 5.57 in group BC, 16.71 ± 5.0 in group BCM, and 55.11 ± 13.20 in group HBS. The bone formation values in group HBS were significantly higher (p < 0.05) than in groups BC and BCM. (5) Conclusions: Based on these results, it can be concluded that injectable calcium phosphate cement is an osteoconductive material that can be used to fill bone cavities.

Dental implants placed in severely atrophic jaws reconstructed with autogenous calvarium, bovine bone mineral, and collagen membranes: A 3- to 19-year retrospective follow-up study

OBJECTIVES

To present the clinical, radiographic, and patient-related outcomes of patients presenting with severely resorbed ridges reconstructed with autogenous calvarial bone blocks and rehabilitated with implant-supported prostheses.

MATERIAL AND METHODS

From 1998 to 2014, 72 patients presenting with severe bone defects were reconstructed with autogenous calvarial bone blocks covered with bovine bone mineral granules and collagen membranes. Four to 9 months later, 330 implants were placed and loaded 3-9 months later. The follow-up ranged from 3 to 19 years (mean: 8.1 years). The following parameters were recorded: (a) complication rate of the reconstructive procedure; (b) bone resorption before implant placement; (c) implant survival rate and implant-related complications; (d) peri-implant bone resorption; and (e) patient's satisfaction inquired with a dedicated questionnaire.

RESULTS

No patients developed severe complications, such as complete loss or resorption of the grafts. A dehiscence occurred in six patients, which developed a mild graft resorption. The mean peri-implant bone resorption before implant placement was 0.13 mm (SD ± 0.71). All patients received the planned number of implants. Three patients were lost during the follow-up. The survival rate of implants at the end of the observation period was 98.5%. The mean peri-implant bone resorption ranged from 0.00 to 4.87 mm (mean: 1.11 mm). At last, 90% of the patients were very satisfied as regards the treatment received.

CONCLUSIONS

Results from this study suggested that: (a) bone volume in the areas reconstructed with calvarial grafts was stable over time; (b) survival rates of implants were consistent with those reported for implants placed in native bone; (c) patient's satisfaction was high.

Success rates and complications of autologous onlay bone grafts and sinus lifts in patients with congenital hypodontia and after trauma

Autogenous bone remains the gold standard for augmentation of the alveolar ridge in congenital hypodontia and appreciable post-traumatic deformity. This generally reflects the volume of material required for such defects and the osteogenic potential of the grafts. Morbidity at the donor site and success rates may lead to autogenous grafts being superseded by xenografts or alloplastic materials in the future, but we know of little evidence to confirm this. All patients having augmentation of the alveolar ridge or sinus lift to enable subsequent placement of implants between 01 January 2009 and 31 December 2016 were identified from a prospectively-gathered database held at the Queen Elizabeth Hospital, Birmingham. Morbidity was recorded, with overall success defined as a graft that enabled subsequent placement of an implant. During this period the following grafts: calvarial (n=4), iliac crest (n=4), and ramus (n=149) were recorded, as well as 53 sinus lifts. Sinus lift augmentation with BioOss^® had the highest success rate (51/53). Calvarial and iliac crest grafts had higher failure rates (2/4 and 3/4, respectively) than those from the mandibular ramus (6/149, 4%). Fifteen of 149 (10%) ramus grafts resulted in transient anaesthesia of the inferior alveolar nerve but no patients developed any permanent morbidity at the donor or recipient sites. Ramus grafts are a predictable method of bone augmentation with only transient morbidity at the donor site. Higher failure rates for extraoral grafts probably reflect their use in more challenging cases when more bone is required. Bilateral ramus grafts are an alternative to extraoral grafts and may be supplemented by bovine-derived particulate grafts with no appreciable increase in complications.

Reconstruction of mandibular vertical defects for dental implants with autogenous bone block grafts using a tunnel approach: clinical study of 50 cases

The objective of this study was to evaluate the outcomes of mandibular vertical defect reconstruction with autologous bone and the use of a sub-periosteal tunnel approach in preparation for dental implant insertion. Forty-three consecutive patients with an atrophic posterior mandible were reconstructed using this method. Two thin laminae of cortical bone, obtained by splitting blocks harvested from the retromolar area, were fixed in a box-like framework containing cancellous and particulate bone. The goal was to achieve an alveolar ridge width of ≥5.5mm and an effective bone height (EBH) of ≥10.5mm for dental implant insertion (≥3.4mm diameter, ≥9.5mm length). Fifty reconstruction procedures were performed. The mean EBH was 7.1±1.3mm pre-treatment and 12.3±1.1mm post-treatment (mean increase 5.2±1.4mm). Complete graft loss was recorded in two cases; the remaining complications were minor. After a mean consolidation period of 3.5 months, 96 dental implants were placed. No failure of osseointegration was observed at follow-up (mean 32.9 months). The average bone height reduction was 0.9mm (graft vertical resorption 17.4%). Reconstruction of posterior mandibular vertical defects using two autogenous cortical bone blocks with particulate bone between them, combined with a tunnelling technique, provided good healing with no wound dehiscence and minimum resorption of the grafted bone, favouring a substantial vertical bone gain.