Bone Augmentation Procedures Research Articles

Narrow-diameter implants: A systematic review and meta-analysis.

Narrow-diameter implants (NDI) are claimed to be a reasonable alternative to bone augmentation procedures. The aim of this comprehensive literature review was to conduct a meta-analysis comparing the implant survival of NDI and standard diameter implants (SDI) and to provide recommendations and guidelines for application of NDI. An extensive systematic literature search was performed in the PubMed/MEDLINE and the Cochrane Library databases. NDI were classified into Category 1 (implant diameter <3.0mm, "mini-implants"), Category 2 (implant diameter 3-3.25mm) and Category 3 (implant diameters 3.3-3.5mm). Clinical studies at all levels of evidence with at least 10 patients included and a follow-up time of at least 12months were included. The primary outcome criterion was the survival rates of NDI. Seventy-six studies were identified for qualitative and 16 studies for quantitative synthesis. Quality assessment illustrated a high risk of bias for the included literature. Mean implant survival rates were 94.7±5%, 97.3±5% and 97.7±2.3% for Categories 1, 2 and 3. Meta-analysis indicated a statistically significant lower implant survival of Category 1 NDI compared to SDI ([OR], 4.54; [CI], 1.51-13.65). For Category 2 and Category 3, no statistical significant differences in implant survival were seen compared to SDI ([OR], 1.06; [CI], 0.31-3.61 and [OR], 1.19; [CI], 0.83-1.70). NDI of Category 1 performed statistically significantly worse than SDI and were mainly described for the rehabilitation of the highly atrophic maxilla or mandible. Category 2 and Category 3 NDI showed no difference in implant survival compared to SDI. Category 2 NDI were mostly used for the rehabilitation of limited interdental spaces in anterior single-tooth restorations. NDI of Category 3 were described in all regions, including posterior single-tooth restorations. However, resilient long-term data and data on the possible risk of biological and technical complications with wide platform teeth on NDI are missing so far.

Experimental and numerical investigations of fluid flow in bioreactors for optimized in vitro stem cell loading in xenografts

Abstract In tissue engineering and regenerative medicine mesenchymal stem cells (MSC) are widely used to replace and restore the function of dysfunctional or missing tissue. Recent studies have shown significant enhancements of the in vivo healing process following dentofacial bone augmentation procedures employing stem cell-loaded xenografts. We conducted experimental and numerical investigations in perfusion flow bioreactor-xenograft-systems to identify flow conditions as well as bioreactor design features that allow for homogeneous MSC-distribution in Geistlich Bio- Oss Block xenografts. Pressure gradient - velocity characteristics and flow distributions were investigated experimentally and numerically for two bioreactor designs at steady-state flow conditions with Reynolds numbers (Re) ranging from 0.01 ≤ Re ≤ 0.32. Distilled water at 20°C with a dynamic viscosity of 1.002 mPa∙s and a density of 998 kg/m3 was used. The geometry of the xenograft utilized in three-dimensional computational fluid dynamics (CFD) simulation was obtained by means of micro-computed tomography (μCT) at an isotropic spatial resolution of 9.5 μm. The permeability values calculated from the experimental data are in good accordance with the numerical results. The investigations showed that the increase of the inflow- and outflow-area diameter, as well as the decrease of the volumetric flow rate, result in a decreasing heterogeneity of the flow distribution within the xenograft. The calculated wall shear stress rates in the three-dimensional (3D) scaffold range from 1∙10-12Pa ≤ τ ≤ 0.2 Pa. Experimentally validated CFD simulations introduced in this study provide an applicable tool to assess optimal flow conditions for homogeneous MSC distribution in bioreactor-xenograft-systems.

Micro-CT evaluation of the cortical bone micro-architecture in the anterior and posterior maxilla and the maxillary sinus floor

ObjectivesTo perform a within-subject comparison of the cortical bone micro-architecture of the maxillary sinus floor (MSF) to that of the buccal aspect of the anterior and posterior maxilla.MethodsMicro-CT scans of the buccal aspect of the anterior and posterior maxilla and of the MSF in 14 human anatomical specimens were recorded. Within-subject comparisons were performed for cortical thickness (Ct.Th) and porosity (Ct.Po), average pore volume (AvgPo.V), and pore density (Po.Dn).ResultsThe MSF presented the lowest and the anterior maxilla the highest Ct.Th, while Ct.Po was significantly higher at the MSF compared to the posterior maxilla (p = 0.021). No relevant differences were recorded for AvgPo.V and Po.Dn among regions (p > 0.067). Further, an increased Ct.Th at the MSF was significantly associated with a lower Po.Dn, while a higher Ct.Th and an increased AvgPo.V in the anterior maxilla were associated with a higher Ct.Th and an increased AvgPo.V, respectively, in the posterior maxilla and MSF. Finally, within each region, the AvgPo.V was associated positively with Ct.Po and negatively with Po.Dn.ConclusionsThe cortical bone of the MSF is slightly less thick and slightly more porous compared to the cortical bone at the buccal aspect of the anterior and posterior maxilla.Clinical relevanceDuring lateral and vertical bone augmentation procedures, the cortical recipient bone is perforated several times to open the bone marrow compartment to facilitate provision of osteoinductive cells and molecules in the augmented space. Whether it is meaningful to approach the MSF in a similar way during MSF augmentation procedures or whether the slightly more porous structure of the MSF observed herein reduces the cortical barrier function already sufficiently has to be assessed in future clinical trials.

Short Implants and Conventional Implants in The Residual Maxillary Alveolar Ridge: A 36-Month Follow-Up Observation.

BackgroundShort dental implants are considered an alternative method of treatment to the maxillary sinus elevation and bone augmentation procedure at the sites of a reduced alveolar ridge height.The aim of the study was to determine the most effective therapeutic approach for a single tooth replacement in a reduced maxillary alveolar crest.Material/MethodsWe enrolled 30 partially edentulous patients having a residual crestal height of 6 mm and a minimal width of the alveolar ridge of 6–7 mm: 15 patients received regular dental implants (OsseoSpeed™ L11 Ø4 mm and L13 Ø4 mm) and the implantation was preceded by the sinus lift procedure from a lateral window approach with the application of a xenogeneic bone graft, whereas the remaining 15 patients received short implants (OsseoSpeed™ L6 mm Ø4 mm) without the sinus lift and augmentation procedure.All implants were loaded with single non-splinted crowns. Radiological examination (CBCT, RVG) was performed before the surgery and after 36 months. Primary and secondary stabilization with Osstell ISQ® and Periotest® were assessed.ResultsGood results in primary and secondary stability were achieved in both systems. The marginal bone level (MBL) loss was low (0.22±0.46 mm and 0.34±0.24 mm, for short and conventional implants, respectively). No significant difference in MBL between groups was found.ConclusionsShort implants can be successfully used to support single crowns in the lateral part of the maxilla.

Use of Quadruple Zygoma Implants Technique for Atrophic Maxilla Rehabilitation with Immediate Loading - A Clinical Case Report

The maxilla with great atrophy can be due to various factors such as tumor resection, generalized aggressive periodontitis, genetic disorders or syndromes. The rehabilitation of patients with an atrophic edentulous maxilla presents a significant challenge for surgeons, and the treatment concept with zygomatic implants have evolved as an alternative for bone augmentation procedures.

A retrospective study of 30,959 implants: Risk factors associated with early and late implant loss.

This retrospective study assessed the risk factors associated with early and late implant loss at the patient- and implant-based analysis. A total of 18,199 patients received 30,959 dental implants during the years 2011-2015. Age, gender, jaw, location, implant brands, implant length and diameter, bone augmentation procedures, and the number of implants placed per patient were recorded. A multivariate generalized estimating equation (GEE) logistic regression was used to identify risk factors related to both early and late implant loss. The cumulative survival rates were 98.0% for patients and 98.7% for implants after 1-6years observation time. A total of 183 patients with 194 implants were lost before or at the abutment connection, and 193 patients with 209 implants were lost after occlusal loading of the implant fixture. The multivariable GEE logistic regression showed that males, patients aged ≥41years, and mandibular anterior location were risk factors for early implant loss. In the case of late implant loss, males, patients aged ≥41years, bone augmentation and short implants were correlated with a significantly increased failure rate. General factors such as male sex, elderly patients, mandibular anterior location, bone augmentation and short implants were associated with implant loss.

Prosthetic rehabilitation of patients with hypohidrotic ectodermal dysplasia: A systematic review.

Hypohidrotic ectodermal dysplasia (HED) comprises a large group of inherited disorders of ectodermal structures, characterised by hypo- or anhidrosis, hypotrichosis and hypo- or oligo- or anodontia. We aimed to systematically assess the spectrum of prosthodontic approaches with regard to the patients' age and to provide clinical implications for practicing dentists. An electronic and manual search was conducted in four databases (Medline, LIVIVO, Cochrane Library, Web of Science Core Collection). Publications of multiple study designs written in English or German without data restrictions, reporting on prosthodontic treatment of patients diagnosed with HED and afflicted with oligo- or anodontia, were included. In total, 75 articles on 146 patients were analysed according to the patients' age. In children aged 2-17years, removable full or partial (over)dentures represented standard treatment. In the mandible, implant-supported removable dentures on two interforaminal implants presented an alternative, already in young childhood. In cases with more than six teeth per jaw, also fixed (resin) bridges were used, frequently after orthodontic treatment. In adults, fixed or removable reconstructions with the help of up to eight implants per jaw, usually placed after bone augmentation procedures, were standard. Ten case reports/series with long-term follow-up illustrated the need for consistent maintenance including denture renewals. Prosthodontic rehabilitation should start in early childhood and needs to be revised in accordance with the patients' growth. Treatment should be carried out by a multidisciplinary team addressing variable demands in different age groups.

Vertical 3D Bone Reconstruction with Simultaneous Implantation: A Case Series Report.

Tooth loss generally leads to a corresponding loss of supporting bone structures, jeopardizing correct implant placement. Bone augmentation procedures facilitate reconstruction of the alveolar contours but lengthen treatment time by about 4 to 9 months. The aim of this case series report is to describe the short-term results of the combination of three-dimensional bone augmentation using the shell technique in conjunction with simultaneous implantation. A total of 10 patients who underwent autologous bone augmentation using the shell technique with simultaneous implantation were retrospectively examined. The shell technique is an augmentation procedure using thin cortical bone plates adapted to the buccal and oral walls of the defect to rebuild the contours of the alveolar ridge. The remaining spaces are filled with bone chips. Healing time before second stage surgery was 4 months. The vertical bone defect at the beginning (VD), the height of the vertical bone graft, resorption at the time of second-stage surgery (BR1) and 1 year after prosthetic rehabilitation (BR2), the total resorption between augmentation and 1 year (BRtot), and the vertical bone loss of the implant (VBL) were measured. VD was 3.1 mm. Values for BR1 and BR2 were 0.4 and 0.45 mm, respectively, resulting in a total bone loss of 0.85 mm of bone loss (BRtot). VBL was 0.45 mm 1 year after prosthetic rehabilitation. The simultaneous approach of vertical bone augmentation in the shell technique and implantation shows excellent results in bone reconstruction and stability up to 1 year after prosthetic reconstruction and can shorten treatment time by 4 to 9 months.

Short Dental Implants (≤7mm) Versus Longer Implants in Augmented Bone Area: A Meta-Analysis of Randomized Controlled Trials.

Aim:The aim of this systematic review was to compare the survival rate and the marginal bone loss between short implants (≤7 mm) placed in the atrophic area and longer implants placed in the augmented bone area of posterior regions of maxillaries.Methods:Electronic search using three databases was performed up to May 2017 to identify Randomized Controlled Trials (RCT) assessing short implants survival with a minimal follow-up of 12 months post-loading. For the meta-analysis, a Risk Difference (RD) with the 95% Confidence Interval (CI) was used to pool the results of implant failure rate for each treatment group. For the marginal bone changes, Mean Differences (MD) with 95% CI were calculated.Results:Seven randomized controlled trials met the inclusion criteria, being included in qualitative and quantitative analyses. The RD between the short implant group and the control group was -0.02 (95% CI: -0.04 to 0.00), I2=0 and Chi2=3.14, indicating a favorable survival rate for short implant, but with no statistical significance (p=0.09).Discussion:For marginal bone loss, the mean difference was -0,13 (95%CI: -0.22 to -0.05), favoring the test group with statistical significance (p=0.002). The studies showed more heterogeneity for bone loss compared to survival rate. Short and longer implants showed similar survival rates after one year of loading, however the marginal bone loss around short implants was lower than in longer implants sites.Conclusion:Placement of implants ≤7 mm of length was found to be a predictable alternative for the rehabilitation of atrophic posterior regions, avoiding all the disadvantages intrinsic to bone augmentation procedures.

Leucocyte- and platelet-rich fibrin block for bone augmentation procedure: A proof-of-concept study.

The objective of this proof-of-concept study was to investigate the effects of a new guided bone regeneration technique with a tissue engineering approach. This single cohort observational study evaluated the outcome of the leucocyte- and platelet-rich fibrin (L-PRF) Block for horizontal bone augmentation in the maxilla. The L-PRF Block is prepared by mixing a particulated biomaterial with chopped L-PRF membranes at a 50:50 ratio and adding liquid fibrinogen to glue all together. Horizontal augmentation was assessed linearly and volumetrically immediately after surgery and 5-8months later by matching consecutive cone beam computed tomography (CBCTs). Ten patients (mean age of 50.7years [±17.2]) representing 15 sites with horizontal alveolar deficiencies were included. Superimposition of pre-operative and posthealing CBCT scans showed an average linear horizontal bone gain of 4.6mm (±2.3), 5.3mm (±1.2) and 4.4mm (±2.3), measured at 2, 6 and 10mm from the alveolar crest, respectively. The volumetric gain was 1.05cm3 (±0.7) on average. The resorption rate after 5-8months was 15.6% (±6.7) on average. L-PRF Block may be a suitable technique to augment deficient alveolar ridges.

Effects of lateral bone augmentation procedures on peri-implant health or disease: A systematic review and meta-analysis.

This systematic review evaluated the evidence on the effect of the interventions aimed for lateral ridge augmentation (both simultaneously with implant placement or as a staged procedure) on peri-implant health or disease. A protocol was developed to answer the following PICO question: "In patients with horizontal alveolar ridge deficiencies (population), what is the effect of lateral bone augmentation procedures (intervention and comparison) on peri-implant health (outcome)?" Included studies were randomised controlled trials or controlled clinical trials with a follow-up of at least 12months after implant loading. Meta-analyses were performed whenever possible, including subgroup analysis based on follow-up. Twelve final publications from eight investigations were included. The results from the meta-analysis indicated that irrespective of the type of intervention, the inflammatory changes, based on bleeding on probing (%) were minimal, both at short- (n=1; weighted mean difference [WMD]=-1.00; 95% CI [-14.04; 12.04]; p=.881) and long-term (n=5; WMD=-5.63; 95% CI [-18.42; 7.16]; p=.881). When comparing different treatment modalities, no significant differences were observed (n=6; WMD=-3.36; 95% CI [-12.49; 5.77]; p<.471). Similarly, changes in probing pocket depth and marginal bone levels were not significantly different among groups. The incidence of peri-implantitis was evaluated in three investigations and varied from 16% to 26% after a follow-up period of 6-8years. The results from this systematic review and meta-analysis have shown that lateral ridge augmentation procedures can maintain peri-implant health over time with low mucosal inflammatory changes and a relatively small incidence of peri-implant bone loss.

Evidence-based knowledge on the aesthetics and maintenance of peri-implant soft tissues: Osteology Foundation Consensus Report Part 2-Effects of hard tissue augmentation procedures on the maintenance of peri-implant tissues.

One task of Working Group 1 at the 2nd Consensus Meeting of the Osteology Foundation was to comprehensively assess the effects of hard tissue augmentation procedures on peri-implant health or disease. One systematic review and meta-analysis on the effects of hard tissue augmentation procedures included a total of eight studies (n=12 publications). Consensus statements, clinical recommendations, and implications for future research were based on structured group discussions and plenary session approval. After 1-10years of follow- up, lateral bone augmentation procedures were associated with peri-implant tissue stability, as evidenced by minimal and non-significant changes in bleeding on probing, probing depth, and marginal bone levels. Case definitions based on clinical and radiographic parameters to differentiate peri-implant health from disease have been inconsistently employed in the studies investigated. Lateral bone augmentation procedures are associated with peri-implant tissue stability on short-term (1-3years) and midterm follow-ups to long-term (>3years) follow-ups.

Bone augmentation followed by implant surgery in the edentulous mandible: A systematic review.

Long-standing loss of natural teeth in the mandible can lead to severe jaw atrophy and even mandibular fracture. There is no consensus on the best pre-prosthetic surgical treatment to reconstruct the atrophic edentulous mandible. The purpose of this review was to provide an overview of the existing literature and to give an evidence-based recommendation for bone grafting and future research. This systematic review was conducted according to the PRISMA statement. A literature search was performed in online databases Pubmed and Cochrane library for articles published between January 1980 and September 2017. The search was conducted using Medical Subject Heading terms: alveolar ridge augmentation; mouth, edentulous and mandible. Eligible articles were included according to in- and exclusion criteria and assessed on quality. Dental implant survival and bone stability were the primary outcomes. Secondary outcomes were complications. Twenty-four text articles matched the criteria and were included. Eleven articles were assessed to be of adequate quality for analysis. Graft stability seems to be higher in vertical distraction and tent-pole grafting, but as the dental implant survival is high (91.7% or higher) regardless of the procedure used for bone augmentation, this is of no clinical relevance. The survival rate of dental implants is high, regardless of the bone augmentation procedure used. High-quality clinical trials are needed to support the current evidence and guidelines on pre-implant bone grafting. Reporting of future research should include proper baseline characteristics and treatment description, as well as uniform outcome rendering.

There seems to be no benefit from using bioactive proteins in bone-augmentation procedures for implant placement

There seems to be no benefit from using bioactive proteins in bone-augmentation procedures for implant placement

Lateral bone augmentation in narrow posterior mandibles, description of a novel approach, and analysis of results.

Combination of particulate grafts and collagen membranes is widely used for augmentation of bony defects for implant placement. Fixation of the barrier membrane may avoid complications due to unfavorable mechanical properties and poor stability leading to collapse of the augmented area. To evaluate a new simplified method for resorbable collagen membrane fixation in lateral bone augmentation procedures in narrow posterior mandibles. This retrospective study analyzed 16 procedures performed in 15 patients who followed lateral ridge augmentation procedures before implant placement in the posterior mandible. A particulate mineralized bone allograft was covered with a cross-linked resorbable collagen barrier membrane, which was fixated with a single, nonresorbable pin. Complications were registered and results analyzed on pre and post op measurements on computerized tomographic scans. Descriptive statistical analysis and ANOVA with repeated measures were performed. No complications were recorded. Average bone gain was 3.3 mm at implant platform level and 4.29 mm at 3 mm apically, both, statistically significant. All sites had sufficient bone width allowing implant placement. Thirty-three implants placed in the augmented areas, integrated and survived for over a 2-year follow-up. The simplified membrane fixation procedure enables large horizontal bone gain with minimal complications while allowing adequate implant placement.

Uncertainty about the benefits of bone augmentation procedures in patients receiving immediate implants

Uncertainty about the benefits of bone augmentation procedures in patients receiving immediate implants

Long-term Retrospective Study based on Implant Success Rate in Patients with Risk Factor: 15-year Follow-up.

The purpose of this retrospective study is to assess implant success rates with various risk factors. Two hundred patients with a total of 650 implants were selected. Risk factors, such as smoking, antidepressants, bruxism, diabetes, and bone augmentation procedures were considered, and patients were followed up for a period of 8 to 15 years. Of 650 implants placed, the success rate was 88%, i.e., a total of 572 implants were successful. A total of 78 implants were considered failure; and out of 78, twenty implants were surgically removed. Based on this study's results, it is concluded that risk factors, such as smoking, bruxism, diabetes, and bone augmentation play an important role in success rate of dental implants. Several factors, such as bruxism, diabetes, and supporting bone can play an important role in dental implant success.

Relationship between cortical bone thickness and implant stability at the time of surgery and secondary stability after osseointegration measured using resonance frequency analysis.

PurposeIt has been suggested that resonance frequency analysis (RFA) can measure changes in the stability of dental implants during osseointegration. This retrospective study aimed to evaluate dental implant stability at the time of surgery (primary stability; PS) and secondary stability (SS) after ossseointegration using RFA, and to investigate the relationship between implant stability and cortical bone thickness.MethodsIn total, 113 patients who attended the Tohoku University Hospital Dental Implant Center were included in this study. A total of 229 implants were placed in either the mandibular region (n=118) or the maxilla region (n=111), with bone augmentation procedures used in some cases. RFA was performed in 3 directions, and the lowest value was recorded. The preoperative thickness of cortical bone at the site of implant insertion was measured digitally using computed tomography, excluding cases of bone grafts and immediate implant placements.ResultsThe mean implant stability quotient (ISQ) was 69.34±9.43 for PS and 75.99±6.23 for SS. The mandibular group had significantly higher mean ISQ values than the maxillary group for both PS and SS (P<0.01). A significant difference was found in the mean ISQ values for PS between 1-stage and 2-stage surgery (P<0.5). The mean ISQ values in the non-augmentation group were higher than in the augmentation group for both PS and SS (P<0.01). A weak positive correlation was observed between cortical bone thickness and implant stability for both PS and SS in all cases (P<0.01).ConclusionsBased on the present study, the ISQ may be affected by implant position site, the use of a bone graft, and cortical bone thickness before implant therapy.

Dental implant placement procedure with simultaneous bone augmentation: A case report and literature review

Bone grafting techniques often constitute the mainstay of treatment used in the restoration of the atrophic maxillary bone before the placement of dental implants. Bone grafting can be achieved with various types of grafting materials; natural or synthetic, though, autogenous bone grafts are still considered the gold standard because of their osteogenic, osteoinductive and osteoconductive properties. The present case report describes the case of a 35-year-old female patient who presented with missing right maxillary central incisor secondary to trauma. Clinical and radiographic examination revealed a severe bone defect requiring a bone augmentation procedure. Hence, guided bone regeneration of the maxillary defect was planned with simultaneous placement of endosseous implant. The present case report, thus, demonstrates the successful use of vertical and horizontal bone augmentation procedures conducted with the help of guided tissue regeneration and simultaneous endosseous implant placement.

The Role of Autologous Platelet Concentrates in Alveolar Socket Preservation: A Systematic Review

Prevention of alveolar bone resorption after tooth extraction may be useful for implant rehabilitation of the edentulous site minimizing the future need for bone augmentation procedures. A number of studies have investigated the efficacy of autologous platelet concentrates for the preservation of the alveolar bone volume after tooth extraction. Although encouraging results have been published, the available data are still controversial. The aim of the present systematic review was to assess the effect of platelet concentrates on alveolar socket preservation after tooth extraction. A literature search was carried out up to September 2017 for prospective controlled trials in which a test group using exclusively a platelet concentrate was compared with a control group in which extraction sockets were left to heal spontaneously. Seven controlled clinical trials published between 2010 and 2016 were included. A total of 320 extractions (170 tests and 150 controls) in 190 patients was considered. A great heterogeneity was found in terms of study design, methodological aspects, and outcome evaluation. For this reason, a quantitative analysis followed by meta-analysis was not possible, and only a descriptive analysis on the role of platelet concentrates in alveolar socket preservation was carried out. There is growing evidence that platelet concentrates may be advantageously used in postextraction sites, mainly to improve soft tissue healing and to reduce postoperative symptoms. Data about their potential in preserving the alveolar bone volume are still scarce and controversial, although recently encouraging results have been presented using more reliable and accurate evaluation technologies, such as the computed tomography. Further, well-designed and methodologically standardized investigations are strongly demanded to reach a higher level of evidence on this topic.