Long-term retrospective evaluation of the peri-implant bone level in onlay grafted patients with iliac bone from the anterior superior iliac crest

Iliac crest vertical block grafts -placing outside or inside the bone contour: A cohort study

OBJECTIVE AND AIM

Challenging defect configurations and dimensions arise from severe, localized vertical alveolar ridge defects caused by trauma or prior surgery. This study aims to analyze three-dimensional bone gain, assess marginal bone stability in such defect configurations, and evaluate the impact of grafting outside the bone contour on the overall outcome, with a focus on iliac crest block grafts as a valid treatment option.

MATERIALS AND METHODS

The prospective cohort study evaluated patients who required vertical block grafting due to localized bone defects in the maxilla or mandible and who had received iliac grafts. Three-dimensional bone gain was analyzed using cone beam computed tomography (CBCT) after 3 months of bone healing for each treated site and implant position. A comparison between bone grafts inside and outside the bone contour was conducted. Marginal bone stability was measured using intraoral radiographs during routine annual follow-up visits.

RESULTS

Seventy patients with 89 treated sites were evaluated. After 3 months of graft healing, the mean vertical bone gain was 11.03 ± 3.54 mm, the mean horizontal bone gain was 7.18 ± 2.00 mm, and the mean graft length was 28.19 ± 11.01 mm. A total of 217 implants were placed in the augmented regions. On implant level, a mean vertical bone gain of 10.44 ± 3.44 mm and a mean horizontal bone gain of 6.54 ± 1.86 mm were measured. Over a 43-month observation period, mesial and distal marginal bone loss averaged 0.44 ± 0.92 mm and 0.49 ± 1.05 mm, respectively. Eight implants were diagnosed with periimplantitis, resulting in the loss of four implants, while no early implant losses were reported.

CONCLUSION

Within the limitations of this study, vertical bone grafts with iliac crest block grafts were found to be a dependable treatment option for dental implant placement, and placing block grafts outside the bone contour did not lead to inferior outcomes.

Vitality of autologous retromolar bone grafts for alveolar ridge augmentation after a 3-months healing period: A prospective histomorphometrical analysis

OBJECTIVES

The incorporation of retromolar bone grafts used for alveolar ridge augmentation is not well understood. This prospective observational study aims to supply histomorphometrical data from bone graft biopsies taken at the time of retrieval and after a 3-month healing period using patient-matched biopsies.

MATERIALS AND METHODS

In 17 patients, trephine biopsies of the graft were acquired at the time of graft retrieval and after a 3-month healing period. The biopsies were compared histomorphometrically regarding the number of osteocytes, appearance of osteocyte lacunae, quantity, surface area, and activity of the Haversian canals.

RESULTS

All grafts appeared clinically stable after screw removal and 17 implants were placed. Histomorphometric analysis revealed no significant difference in the number of osteocytes (p = .413), osteocyte lacunae (p = .611), the ratio of filled/empty osteocyte lacunae (p = .467) and active Haversian canals (p = .495) between the biopsies retrieved after a 3-months healing period with those at the time of grafting. The only significant difference was noted in the mean surface area of the Haversian canals (p = .002). Specifically, the grafts post 3-month healing showed a significantly larger mean area (0.069 mm2) compared to the time of grafting (0.029 mm2).

CONCLUSION

This study demonstrates, compared to other data, a high rate of vital structures in retromolar bone block grafts after 3 months of healing, exhibiting the same histological features in comparison to the biopsies from the native alveolar ridge. Standard histomorphometrical parameters, e.g., the amount of filled or empty osteocyte lacunae for the description of the vitality of the graft need to be reappraised.

Randomized split-mouth clinical trial comparing osteoblastic activity and osteogenic potential of autogenous particle harvesting during implant surgery without irrigation and with irrigation

OBJECTIVE

To compare the osteoblastic activity and osteogenic potential of autogenous particle harvesting during implant surgery using low-speed drilling without irrigation and high-speed drilling with irrigation.

MATERIALS AND METHODS

Thirty patients with bilateral missing teeth of 3.6 and 4.6 were randomized into two groups (Group 1: low-speed drilling without irrigation and Group 2: high-speed drilling with irrigation) and 60 single dental implants were placed. The temperature at the tip of each drill was recorded and the harvested bone was weighed; particle size and Ca and P levels were also analyzed. After osteoblast culture, cell viability, cell cycle assay, cell migration, vascular endothelial growth factor (VEGF) concentration, and mineralized nodule formation were assessed.

RESULTS

Although the temperature of the drills was slightly higher in Group 1, no statistically significant differences were observed (p ≤ 0.05); however, the amount of harvested bone was higher (p < 0.001) and the size of the particles was higher (p = 0.019). In relation to osteoblastic activity and osteogenic potential, higher cell proliferation, higher number of cells in G2/M and S phases, higher cell migration capacity, higher VEGF concentration, and higher amount of mineralized nodule formation were observed in Group 1.

CONCLUSIONS

Low-speed drilling without irrigation does not result in a significant increase in bone temperature compared to conventional drilling. However, a greater amount of bone is obtained; in addition, osteoblastic activity and osteogenic potential are higher with this technique, but further clinical studies are necessary.

Effect of a synthetic hydroxyapatite-based bone grafting material compared to established bone substitute materials on regeneration of critical-size bone defects in the ovine scapula

Lately, the potential risk of disease transmission due to the use of bovine-derived bone substitutes has become obvious, demonstrating the urgent need for a synthetic grafting material with comparable bioactive behaviour and properties. Therefore, the effect of a synthetic hydroxyapatite (HA) (Osbone®) bone grafting material on bone regeneration was evaluated 2 weeks, 1 month, and 3, 6, 12 and 18 months after implantation in critical-size bone defects in the ovine scapula and compared to that of a bovine-derived HA (Bio-Oss®) and β-tricalcium phosphate (TCP) (Cerasorb® M). New bone formation and the biodegradability of the bone substitutes were assessed histomorphometrically. Hard tissue histology and immunohistochemical analysis were employed to characterize collagen type I, alkaline phosphatase, osteocalcin, as well as bone sialoprotein expression in the various cell and matrix components of the bone tissue to evaluate the bioactive properties of the bone grafting materials. No inflammatory tissue response was detected with any of the bone substitute materials studied. After 3 and 6 months, β-TCP (Cerasorb® M) showed superior bone formation when compared to both HA-based materials (3 months: β-TCP 55.65 ± 2.03% vs. SHA 49.05 ± 3.84% and BHA 47.59 ± 1.97%; p ≤ 0.03; 6 months: β-TCP 62.03 ± 1.58%; SHA: 55.83 ± 2.59%; BHA: 53.44 ± 0.78%; p ≤ 0.04). Further, after 12 and 18 months, a similar degree of bone formation and bone-particle contact was noted for all three bone substitute materials without any significant differences. The synthetic HA supported new bone formation, osteogenic marker expression, matrix mineralization and good bone-bonding behaviour to an equal and even slightly superior degree compared to the bovine-derived HA. As a result, synthetic HA can be regarded as a valuable alternative to the bovine-derived HA without the potential risk of disease transmission.

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.

Bone reconstruction of extensive maxillomandibular defects in adults

Reconstruction of significant maxillomandibular defects is a challenge that has been much discussed over the last few decades. Fundamental principles were developed decades ago (bone bed viability, graft immobilization). Clinical decision-making criteria are highly relevant, including local/systemic factors and incision designs, the choice of material, grafting technique, and donor site morbidity. Stabilizing particulated grafts for defined defects-that is, via meshes or shells-might allow significant horizontal and vertical augmentation; the alternatives are onlay and inlay techniques. More significant defects might require extra orally harvested autologous bone blocks. The anterior iliac crest is often used for nonvascularized augmentation, whereas more extensive defects often require microvascular reconstruction. In those cases, the free fibula flap has become the standard of care. The development of alternatives is still ongoing (i.e., alloplastic reconstruction, zygomatic implants, obturators, distraction osteogenesis). Especially for these complex procedures, three-dimensional planning tools enable facilitated planning and a surgical workflow.

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.

Long-Term Outcome of Dental Implants in Immediate Function Inserted on Autogenous Grafted Bone

Background: There is a need for long-term evidence of immediate function dental implants inserted in grafted bone. The aim of this retrospective study was to investigate the outcome of full-arch rehabilitations supported by implants in grafted bone. Methods: Thirty-six patients (women: 24; men: 12; average age: 53.5 years) were included (225 implants). Primary outcome measure: to assess implant cumulative success rates evaluated through life tables. Secondary outcome measures: to evaluate implant and prosthetic survival, marginal bone loss, and the incidence of both biological and mechanical complications. Results: Twenty-five implants were unsuccessful giving a dental implant CS rate of 88.1% at 14 years and a 76.8% survival estimation (Kaplan−Meier) using the patient as the unit of analysis. No prosthesis was lost. Average MBL at 10 years was 2.01 mm. The incidence of biological complications was 36%, with smoking affecting it significantly (p < 0.001). The incidence of mechanical complications was 86.1% (45.2% and 54.8% in provisional and definitive prosthesis, respectively. Conclusions: The rehabilitation of atrophic maxillae through dental implants in immediate function inserted in grafted bone is a valid treatment alternative, despite the relevant rate of implant failures and incidence of complications.

Association of sex steroid hormones and new bone formation rate after iliac onlay grafting: a prospective clinical pilot study

Purpose

The present prospective study evaluates the association between new bone formation rate in the iliac onlay graft and sex steroid hormone serum levels.

Methods

A total of 15 partially or completely edentulous postmenopausal females and 9 males with less than 5 mm height of the remaining alveolar bone underwent iliac onlay grafting followed by dental implant placement using a two-stage approach. Sex hormone binding globulin and 17β-estradiol serum levels were investigated by electrochemiluminescence immunoassay, while total testosterone level was analyzed using radioimmunoassay. At the time of implant placement, 12 weeks after grafting, bone biopsies were obtained and analyzed histomorphometrically. Statistical analysis was performed using linear mixed models.

Results

Grafting procedure was successfully performed in all patients. The mean new bone formation rate was 32.5% (116 samples). In men the mean new bone formation rate (38.1%) was significantly higher (p < 0.01) than in women (27.6%). Independent of gender 17β-estradiol and testosterone were positively associated to overall new bone formation rate, albeit a significant influence was only seen for 17β-estradiol in men (p = 0.020). Sex hormone binding globulin had no influence on new bone formation rate (p = 0.897). There was no significant association between new bone formation rate and age (p = 0.353) or new bone formation rate and body mass index (p = 0.248).

Conclusion

Positive association of 17ß-estradiol as well as testosterone with new bone formation rate after iliac onlay grafting indicates a role of sex steroid hormones in alveolar bone regeneration, although the observed influence was only significant for 17ß-estradiol in men.

Graphical Abstract

Proteomic profiling of human bone from different anatomical sites - A pilot study

PURPOSE

The study aim is a comparative proteome-based analysis of different autologous bone entities (alveolar bone [AB], iliac cortical [IC] bone, and iliac spongiosa [IS]) used for alveolar onlay grafting.

EXPERIMENTAL DESIGN

Site-matched bone samples of AB, IC, and IS were harvested during alveolar onlay grafting. Proteins were extracted using a detergent-based (sodium dodecyl sulfate) strategy and trypsinized. Proteome analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). MaxQuant was used for peptide-to-spectrum matching, peak detection, and quantitation. Linear models for microarray analysis (LIMMA) were used to detect differentially abundant peptides and proteins.

RESULTS

A total of 1730 different proteins were identified across the 15 samples at a false discovery rate of 1%. Partial least-squares discriminant analysis approved segregation of AB, IC, and IS protein profiles. LIMMA statistics highlighted 66 proteins that were more abundant in AB then in IC (vs. 92 proteins were enriched in IC over AB). Gene Ontology enrichment analysis revealed a matrisomal versus an immune-related proteome fingerprint in AB versus IC.

CONCLUSION AND CLINICAL RELEVANCE

This pilot study demonstrates an ECM protein-related proteome fingerprint in AB and an immune-related proteome fingerprint in IS and IC.

Emerging roles of platelet concentrates and platelet-derived extracellular vesicles in regenerative periodontology and implant dentistry

Platelet concentrates (PCs) are easily obtained from autogenous whole blood after centrifugation and have evolved through three generations of development to include platelet-rich plasma, platelet-rich fibrin, and concentrated growth factor. Currently, PCs are widely used for sinus floor elevation, alveolar ridge preservation, periodontal bone defects, guided bone regeneration, and treatment of gingival recession. More recently, PCs have been leveraged for tissue regeneration to promote oral soft and hard tissue regeneration in implant dentistry and regenerative periodontology. PCs are ideal for this purpose because they have a high concentration of platelets, growth factors, and cytokines. Platelets have been shown to release extracellular vesicles (P-EVs), which are thought to be essential for PC-induced tissue regeneration. This study reviewed the clinical application of PCs and P-EVs for implant surgery and periodontal tissue regeneration.

Comparison of the 3D-Microstructure Between Alveolar and Iliac Bone for Enhanced Bioinspired Bone Graft Substitutes

In oral- and maxillofacial bone augmentation surgery, non-vascularized grafts from the iliac crest demonstrate better clinical performance than alveolar bone grafts. The underlying mechanisms are not fully understood but are essential for the enhancement of bone regeneration scaffolds. Synchrotron Radiation µ-CT at a pixel size of 2.3 μm was used to characterize the gross morphology and the vascular and osteocyte lacuna porosity of patient-matched iliac crest/alveolar bone samples. The results suggest a difference in the spatial distribution of the vascular pore system. Fluid simulations reveal the permeability tensor to be more homogeneous in the iliac crest, indicating a more unidirectional fluid flow in alveolar bone. The average distance between bone mineral and the closest vessel pore boundary was found to be higher in alveolar bone. At the same time, osteocyte lacunae density is higher in alveolar bone, potentially compensating for the longer average distance between the bone mineral and vessel pores. The present study comprehensively quantified and compared the 3D microarchitecture of intraindividual human alveolar and iliac bone. The identified difference in pore network architecture may allow a bone graft from the iliac crest to exhibit higher regeneration potential due to an increased capacity to connect with the surrounding pore network of the residual bone. The results may contribute to understanding the difference in clinical performance when used as bone grafts and are essential for optimization of future scaffold materials.

Long-Term Results after Placing Dental Implants in Patients with Papillon-Lefèvre Syndrome: Results 2.5-20 Years after Implant Insertion

Aim: A retrospective evaluation of patients with Papillon-Lefèvre syndrome (PLS) treated with dental implants to identify factors that may influence treatment outcomes. Methods: All PLS patients with dental implants currently registered at the Department of Periodontology, Goethe-University Frankfurt (20–38 years; mean: 29.6 years), were recruited. Five patients from three families (two pairs of siblings) with a total of 48 dental implants (inserted in different dental institutions) were included with a follow-up time of 2.5–20 years (mean: 10.4 years). Results: Implant failure occurred in three patients (at least 15 implants). Nearly all patients demonstrated peri-implantitis in more or less advanced stages; 60% of patients demonstrated bone loss ≥50% around the implants. Two patients did not follow any supportive therapy. Conclusions: Implants in PLS patients who did not follow any maintenance programme had a high risk of peri-implantitis and implant loss.

Retrospective Evaluation of Implants Placed in Iliac Crest Autografts and Pristine Bone

Objective: Iliac crest autografts can compensate for severe mandibular atrophy before implant placement. However, the implant success in the augmented bone is not entirely predictable. Here we performed a retrospective cohort study to determine the success and related parameters of implants placed in augmented bone and pristine bone for up to 11 years. Material and Methods: We analyzed 18 patients where 72 implants were placed six months after iliac crest transplantation and 19 patients where 76 implants were placed in pristine bone. The primary endpoint was implant loss. Secondary endpoints were the implant success, peri-implant bone loss, and the clinical parameters related to peri-implantitis. Moreover, we evaluated the oral-health-related quality of life (OHIP). Results: Within a mean follow-up of 5.8 ± 2.2 and 7.6 ± 2.8 years, six but no implants were lost when placed in augmented and pristine bone, respectively. Among those implants remaining in situ, 58% and 68% were rated as implant success (p = 0.09). A total of 11% and 16% of the implants placed in the augmented and the pristine bone were identified as peri-implantitis (p = 0.08). Bone loss was similar in both groups, with a mean of 2.95 ± 1.72 mm and 2.44 ± 0.76 mm. The mean OHIP scores were 16.36 ± 13.76 and 8.78 ± 7.21 in the augmentation and the control group, respectively (p = 0.35). Conclusions: Implants placed in iliac crest autografts have a higher risk for implant loss and lower implant success rates compared to those placed in the pristine bone.

Esthetic and functional reconstruction of large mandibular defects using free fibula flap and implant-retained prosthetics - a case series with long-term follow-up

Background

The reconstructive and rehabilitative management of large mandibular defects with basal continuity is challenging in many respects, especially in the vertical dimension. The free fibula flap is an under-utilised but efficient approach in this indication. The aim of this case series is to demonstrate its use and long-term success.

Case presentation

Three cases are presented, where the patient had a large bone defect (at least 5 cm in length and 1 cm in the vertical dimension), but the continuity of the mandible was maintained. Two cases were related to pathological fracture and one was a large defect due to oncological surgery. Vertical augmentation with free microvascularised fibula flap was carried out, followed by implant-retained prosthetic therapy. Clinical status has been followed up for 5 to 6 years, with special attention to the condition of the peri-implant tissues and any radiographically detectable alterations or complications. No complications occurred during the follow-up. Function and esthetics have remained unchanged throughout.

Conclusions

Free microvascularised fibula flap reconstruction combined with implant-retained prosthetics allows a lasting functional and esthetic solution in the discussed indication.

Effect of Variable Implant Tip Distances on Stress Distribution around the Mental Foramen: A Finite Element Analysis

AIM: This study aimed to evaluate the effect of gap between traditional implant tip and mental nerve using finite element analysis. METHODS: Four finite element models (FEM) were prepared for dummy crowns that were supported by traditional implants that were placed vertically in laser scanned mandibular bone geometry. Where gap distance were designed to be 1.5, 2.0, 2.5, and 3.0 mm. Dummy crown, 50 μm cement layer, and implant complex models’ components were modeled in 3D on engineering computer-aided design (CAD)/CAD (computer-aided manufacturer) software formerly collected in Finite Element Analysis package. Each model was subjected to two loading cases as 150N compressive load at central fossa, and 50N Oblique (45º) load at central fossa of the dummy crown. RESULTS: Good agreement of the FEM was obtained when compared to similar studies. Under applied study loads, all resulting values of stresses and deformations of the four models were within physiological limits. The obtained data showed no effect on cortical bone, implant complex, cement layer, and dummy crown to changing of gap distance. In addition, the cancellous bone, especially around the mental canal, was considerably affected by the variation in that gap distance. CONCLUSION: Increasing the gap distance between the dental implant tips may reduce the stress and deformation around the mental canal. Minimum gap distance of order 2.5 mm is recommended to reduce stresses and deformations around canal to favorable limits, while more gap distance is also recommended with larger bone geometries.

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 loss-related factors in tissue and bone level dental implants: a systematic review of clinical trials

Dental implants are popular for dental rehabilitation after tooth loss. The goal of this systematic review was to assess bone changes around bone-level and tissue-level implants and the possible causes. Electronic searches of PubMed, Google Scholar, Scopus, and Web of Science, and a hand search limited to English language clinical trials were performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines up to September 2020. Studies that stated the type of implants used, and that reported bone-level changes after insertion met the inclusion criteria. The risk of bias was also evaluated. A total of 38 studies were included. Eighteen studies only used bone-level implants, 10 utilized tissue-level designs and 10 observed bone-level changes in both types of implants. Based on bias assessments, evaluating the risk of bias was not applicable in most studies. There are vast differences in methodologies, follow-ups, and multifactorial characteristics of bone loss around implants, which makes direct comparison impossible. Therefore, further well-structured studies are needed.

Comparison of Success Rate of Dental Implants Placed in Autogenous Bone Graft Regenerated Areas and Pristine Bone

Autogenous bone grafting still has been considered as the "gold standard" and wildly used in the case of alveolar bone reconstruction. The aim of the present study is to evaluate the success rate of implants placed in autogenous block augmented ridges and implants placed in pristine bone (PB). This study included 113 patients. Fifty-three patients were treated with autogenous block grafts and particulate bone, after 6 months of healing implant placements were performed in autogenous bone augmented (ABA) areas. In 60 patients implant placement was performed, with no need for grafting and implants were placed into the PB. Follow-up data (pain, mobility, exudation from peri-implant space, success rate, marginal bone resorption) were collected after 5 years of prosthetic loading. The cumulative implant success rate at the 5-year examination was 92.45% for the ABA group and 85% for PB group. There were 3 failed implants in the ABA group and 3 in PB group. Average marginal bone loss was 1.47 mm on ABA group and 1.58 mm on PB group. No statistically significant differences for pain, exudation from peri-implant space, implant mobility, implant success, peri-implant bone loss parameters, and patient satisfaction level were found between groups. The obtained data demonstrated that the success rate of implants placed in regenerated areas are very similar to the success rate of implants those placed in PB.

MRI for the display of autologous onlay bone grafts during early healing-an experimental study

OBJECTIVES

Autologous bone grafts are the gold standard to augment deficient alveolar bone. Dimensional graft alterations during healing are not known as they are not accessible to radiography. Therefore, MRI was used to display autologous onlay bone grafts in vivo during early healing.

METHODS AND MATERIALS

Ten patients with alveolar bone atrophy and autologous onlay grafts were included. MRI was performed with a clinical MR system and an intraoral coil preoperatively (t0), 1 week (t1), 6 weeks (t2) and 12 weeks (t3) postoperatively, respectively. The graft volumes were assessed in MRI by manual segmentation by three examiners. Graft volumes for each time point were calculated and dimensional alteration was documented. Cortical and cancellous proportions of bone grafts were assessed. The intraobserver and interobserver variability were calculated. Statistical analysis was performed using a mixed linear regression model.

RESULTS

Autologous onlay bone grafts with cortical and cancellous properties were displayed in vivo in eight patients over 12 weeks. The fixation screws were visible as signal voids with a thin hyperintense fringe. The calculated volumes were between 0.12-0.74 cm³ (t1), 0.15-0.73 cm³ (t2), and 0.17-0.64 cm³ (t3). Median changes of bone graft volumes of -15% were observed. There was no significant difference between the examiners (p = 0.3).

CONCLUSIONS

MRI is eligible for the display and longitudinal observation of autologous onlay bone grafts. Image artifacts caused measurements deviations in some cases and minimized the precise assessment of graft volume. To the knowledge of the authors, this is the first study that used MRI for the longitudinal observation of autologous onlay bone grafts.

Resorption of retromolar bone grafts after alveolar ridge augmentation-volumetric changes after 12 months assessed by CBCT analysis

In this pilot study, a volumetric analysis of retromolar onlay bone grafts over a period of 12 months was conducted, using repeated CBCT imaging combined with automated image registration.

Eleven patients being treated with 16 bone grafts taken from the retromolar area were examined by CBCT scanning prior to bone augmentation (T0), immediately after bone augmentation (T1) and after a healing time of 12 months after augmentation (T2). Graft volumes were measured at each time point after automated image registration of consecutive CBCT scans.

The mean volume of the augmented site was 372.2 ± 179.4 mm³. Resorption relative to the original augmented volume was 43.7% ± 19.0% after 12 months.

Three-dimensional graft resorption could be precisely depicted by the use of automated image registration for CBCT data over a period of 12 months and demonstrated extensive volumetric changes of bone grafts taken from the ascending ramus of the mandible.

Graft resorption and continuous bony remodeling of the grafted site before and after implant insertion have to be carefully considered by the clinician.

Maxillofacial Bone Grafting Materials: 2021 Update

For successful outcomes in bone grafting, it is important to have a clear and detailed understanding of the fundamentals and basics in regenerative science. This article summarize the grafting materials and growth factors that are now in use to provide an improved understanding of the properties of each material and indications for subsequent use. The article gives an overview of the fundamentals of bone healing, including the physiology of regeneration. It is hoped that clinicians can make improved decisions that are based in literature when considering treatment options for restoring patients' functional dentition.

Horizontal bone grafting using equine-derived cancellous bone blocks is associated with severe complications: A prospective clinical and histological pilot study

AIMS

The aim of this prospective, clinical study was to evaluate the clinical performance and histological outcome of a new equine hydroxyapatite collagenated bone block (eHAC) for horizontal bone grafting prior to implant placement.

MATERIALS AND METHODS

Five patients (two male/three female) with a mean age of 51.6 years (range 22-66 years) and a reduced horizontal bone width of the alveolar ridge (mean 3.5 mm) underwent horizontal bone grafting using eHAC at 10 grafting sites. Reentry was performed 6.9 months after the horizontal grafting procedure. Clinical follow-up (mean 28.9 month) considered width gain of the alveolar ridge, soft tissue healing, and complications. To evaluate graft incorporation, four additional patients underwent histological assessment of equine blocks adjacent to autologous blocks 3 and 6 months after grafting.

RESULTS

The study was terminated after graft failure was observed in four of five patients. Mean horizontal bone width had increased by 3.6 ± 1.22 mm. Three out of nine implants placed had to be removed due to graft failure. Histological evaluation revealed large amounts of soft connective tissue within the grafts (mean 67.3 ± 9.5%). The proportion of new bone formation 3 months after the lateral grafting procedure revealed an average of 8.6%, compared to 11.4% after 6 to 7 months.

CONCLUSION

Lateral ridge grafting using eHAC achieved measurable horizontal width gain but revealed high rates of severe complications.

CLINICAL IMPLICATIONS

Within the limitations of this study, eHAC bone blocks cannot be recommended for horizontal bone grafting.

Clinical Performance of Short Expandable Dental Implants for Oral Rehabilitation in Highly Atrophic Alveolar Bone: 3-year Results of a Prospective Single-Center Cohort Study

Background and Objectives: Oral health-related quality of life (OHRQOL) is compromised during the post-implant healing period, especially when vertical augmentation is required. A long-term trial sought to evaluate a short dental implant system with an apically expandable macro-design. Materials and Methods: Over 4.5 years, patients with limited vertical alveolar bone were consecutively recruited into this prospective cohort study. Implant success rate, OHRQOL (Oral Health Impact Profile (OHIP)-14), implant stability, and crestal bone changes were evaluated. Results: Data from 30 patients (mean age: 64.6 years, range 44–83) were analyzed, which related to 104 implants (53 in the maxilla, 51 in the mandible). Over the mean follow-up (42.6 ± 16.4 months), the implant success rate was 94.7% in the mandible (two implants lost) and 83.6% in the maxilla (four implants lost; p = 0.096), and the prosthetic success rate was 100%. The median OHIP-14 scores improved from 23 (interquartile range (IQR) 9–25.5) to 2 (IQR 0–5; p < 0.001). The mean implant stability quotient (ISQ) was 71.2 ± 10.6 for primary stability and 73.7 ± 13.3 (p = 0.213) for secondary stability, without significant maxilla-versus-mandible differences (p ≥ 0.066). Compared to the baseline, median crestal bone changes after loading were 1.0 mm (IQR 0–1.3) and 1.0 mm (IQR 0.2–1.2) in the maxilla and mandible (p = 0.508), respectively, at the end of the first year, 1.1 mm (IQR 0–1.3) and 1.0 mm (IQR 0.1–1.2) (p = 0.382), respectively, at the end of the second year, and 1.2 mm (IQR 0–1.9) and 1.1 mm (IQR 0.1–1.2) (p = 0.304), respectively, at the end of the third year. Conclusions: In patients with limited vertical bone height, short implants with optimized macro-design constitute a reliable method for functional rehabilitation, avoiding extensive alveolar bone augmentation.

Maxillofacial Bone Grafting Materials

The goal of bone grafting is to replace normal bone volume and structure with healthy, well-vascularized bone that will undergo normal remodeling. The ideal bone will regenerate bone and not repair it. Currently four types of grafting material are available to clinicians for regenerative use in oral and maxillofacial surgery: autologous bone, allogeneic bone, xenogenic bone, and alloplastic bone. Additionally, bioactive agents, growth factors, are now being used to stimulate osteoinductive properties of native bone for bone regeneration. This article reviews the literature and summarizes the benefits and disadvantages of each respective graft and illustrates its use in clinical practice.

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.

Donor-site Morbidity after Retromolar Bone Harvesting Using a Standardised Press Fit Cylinder Protocol

Precise fitting and immobilisation of bone transplants at the recipient site is of utmost importance for the healing process. With the help of the standardised Osseo Transfer System, the recipient site is adjusted to the graft, rather than vice versa as it is typically done. The aim of this study was to analyse donor-site morbidity after harvesting cylindrical bone grafts from the retromolar region using the Osseo Transfer System. The patient satisfaction with the surgical procedures was also evaluated. All patients treated with this standardised reconstruction method between 2006 and 2013 at the Department of Cranio-Maxillofacial Surgery, University Hospital Giessen, were included in this study. Complications were recorded and evaluated. Bone graft success and patient satisfaction were documented with a questionnaire, and then confirmed by clinical and radiological follow-up examinations. Fifty-four patients were treated and 64 harvested cylindrical autologous bone grafts were transplanted. In all cases, dental implants could be inserted after bone healing. One patient lost an implant, associated with failure of the bone graft. Six patients who were examined continued to show neurological disorders in locally limited areas. No complete or long-term damage of the inferior alveolar nerve occurred. More than 94% (n = 52) of the patients were 'very satisfied' or 'satisfied' with the results and would recommend this surgical treatment to other patients. The standardised Osseo Transfer was an effective treatment option for small and mid-sized alveolar ridge augmentations. A low donor-site morbidity rate and a high transplant success rate were verified. The Osseo Transfer System demonstrated to be a reliable surgical technique without major complications. We highly recommend this surgical augmentation procedure as a surgical treatment for local bone defects.

Oral Rehabilitation of Hypodontia Patients Using an Endosseous Dental Implant: Functional and Aesthetic Results

Hypodontia often leads to limited bone availability of the alveolar ridges. Oral rehabilitation of severe hypodontia patients is challenging. In this retrospective study, we evaluated the functional and aesthetic results after dental implants in hypodontia patients, corroborated by Albrektsson implant success criteria. Over a period of 15 years (2000–2015), a total of 43 patients were diagnosed with hypodontia and 165 dental implants were inserted. Six patients who received 10 implants were lost in the follow-up. We examined 155 implants in 37 patients between December 2015 and May 2017. Besides family history, patients evaluated the general satisfaction, functionality, and aesthetics of the implants. Study subjects were between 17 and 44 years old (mean ± SD: 21.4 ± 5.6). Hypodontia patients were missing one to five teeth (n = 28), whereas patients diagnosed with oligodontia (≥6 missing teeth, n = 9). In this study, 24 patients (64.9%) with hypodontia had a positive family history; the remaining 13 patients had no family member with hypodontia. The final follow-up time ranged between 5 and 189 months after implant placement. Orthodontic treatment was performed in 32 patients (86%) before implant placement. Rehabilitation resulted in 62% of the cases being treated with 1–2 implants and 38% treated with 3–15 implants. However, out of 155 inserted dental implants, 18 implants failed to meet Albrektsson criteria, under which two implants were removed. Only autografts were used for bone augmentation with 97 implants. More than two-thirds of the patients showed high general satisfaction and masticatory function (69.4%) as well as phonetic ability (80.6%). The aesthetic outcome was rated as excellent by 17 patients (47.2%). The findings emphasize the importance of interdisciplinary treatment of hypodontia, leading to a satisfactory, functional, and long-term fixed prosthodontics using dental implants.

Rehabilitation of atrophic jaw using iliac onlay bone graft combined with dental implants

Background

Rehabilitating severely atrophic alveolar crests remains challenging for implantologists and maxillofacial surgeons. Recently, a combination of augmentation and dental implantation has been used to treat cases with severe bone atrophy in the maxilla and mandible. Among autogenous bone grafts, iliac bone grafting (IBG) is considered safe for collecting large amounts of bone and obtaining high-density multipotent cells. However, vertical bone resorption may occur during the initial healing stage after IBG. The purpose of the present study is to evaluate bone graft success and implant survival rate, along with bone height in the augmented site and marginal bone level around dental implants placed in iliac onlay bone grafts. We also introduce technique and treatment considerations for successful IBG procedures, as well as optimal implant installation strategy and soft tissue manipulation.

Methods

We examined seven patients who were treated with IBG combined with implant systems over a period of 10 years. The long-term success rate of bone grafts and implant survival rate were recorded. Bone height change and marginal bone loss (MBL) were analyzed by assessing the radiograms acquired after augmentation, at implant installation, prosthetic loading, and after installation 1 year, 2 years, 3 years, and 5 years.

Results

In a mean observation period of 50 months (range 12–62 months), the success rate of IBG was 100%. A total of 29 implants were installed and the implant success rate was 100%. The mean bone height reductions compared to post-augmentation bone heights were 1.33 ± 0.81 mm after 3 months, 2.00 ± 1.88 mm at implant installation, 2.55 ± 1.68 mm at prosthetic loading, and 3.05 ± 1.63 mm after implant installation 1 year. The cumulative bone height change after implant installation 5 years was 4.05 ± 1.83 mm which corresponds to a mean resorption rate of 42.5%. The mean MBL after installation 3 months, at prosthetic loading, and after installation 1 year, 2 years, 3 years, and 5 years follow-ups were significantly higher than at implant installation. However, MBL at 2 years, 3 years, and 5 years post-installation did not differ significantly (p < 0.05).

Conclusion

In patients with atrophic jaws, a combination of the iliac onlay bone graft and dental implants can result in satisfactory reconstruction and reliable long-term prognosis. Despite early stage vertical bone resorption, we observed high success rates and comparable MBL over long-term follow-up. To reduce bone resorption, case evaluation and surgical planning must be meticulous. Further large-scale studies with longer-term follow-up are needed.

Dental implants placed in resorbed alveolar ridges reconstructed with iliac crest autogenous onlay grafts: A 26-year median follow-up retrospective study

PURPOSE

To evaluate the long-term outcome of dental implants placed with a staged procedure in resorbed alveolar ridges reconstructed with iliac crest autogenous onlay grafts.

MATERIALS AND METHODS

All consecutive patients treated with iliac crest onlay bone grafts and dental implants were retrospectively evaluated. During the appointment, clinical and radiological examinations were conducted to assess implant survival. A survived implant was defined as an implant still stable and in function at the follow-up visit. Implant survival was estimated at the implant level using Kaplan-Meier analyses. The cumulative survival rate was estimated using a life-table analysis. Subgroup analyses were performed for age, position, and type of retention using the log-rank test. A p-value of <0.05 was considered statistically significant.

RESULTS

The cohort consisted of 21 female subjects receiving a total of 140 rough-surface titanium implants. Of them, 128 survived and 12 failed, yielding a cumulative survival rate of 91.1% over a median survival time of 312 months. Implants supporting cement-retained prostheses exhibithed lower survival rate compared to screw-retained restorations (p = 0.001).

CONCLUSION

Implants placed in bone augmented with iliac crest onlay grafts showed high long-term survival rates. Cement-retained restorations were more prone to develop implant failures.

Comparative Outcomes of Block and Cancellous Iliac Bone Grafting in Older Unilateral Alveolar Cleft Patients

OBJECTIVE

To compare osseous outcomes of block and cancellous iliac bone grafting in older unilateral alveolar cleft patients.

DESIGN

Retrospective and observational follow-up study.

SETTING

Cleft Lip and Palate Centre, Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, China.

PATIENTS

Forty-five nonsyndromic patients with unilateral complete alveolar cleft were enrolled in this study (25 patients in block bone graft group and 20 patients in cancellous bone graft group).

INTERVENTIONS

In cancellous bone graft group, the alveolar cleft was filled with iliac cancellous bone particulate. In group of block bone graft, the harvested bone block was trimmed and fixed in alveolar defect.

MAIN OUTCOME MEASURES

A novel method was proposed to investigate the volume and density of residual bone graft at 1-week, 3- and 6-month, 1- and 2-year postoperatively based on cone beam computed tomography scans.

RESULTS

No difference in bone graft volume was found between 2 groups at 1-week and 3-month postoperatively; however, the residual volume of block bone graft group was significantly larger than that of cancellous bone graft group at 6-month, 1- and 2-year postoperatively. The bone density of block bone graft group was lower at 1-week and 3-month postoperatively but was comparable at 6-month, 1- and 2-year postoperatively. Our method was reliable and accurate to identify the range of residual bone graft when the boundary of grafted bone could not be identified clearly.

CONCLUSION

Block bone graft could achieve comparable bone density and retain a greater amount of residual bone comparing to cancellous bone graft.

Mandibular Augmentation With a New Sandwich Osteotomy: A Morphologic Study

OBJECTIVE

Facial asymmetry is one of common complaints in plastic and craniofacial surgery in Orient. Hemimandibular dysplasia has considered to be the key role in facial asymmetry. Despite of the undergrow of mandibular length and height, the lackness of mandibular thickness contributes to the asymmetry. The aim of this study was to describe the therapeutic efficiency of mandibular augmentation with a new sandwich osteotomy with interpositional natural coral and coralline hydroxyapatite (CHA).

METHODS

Nine goats were randomly divided into 3 groups and observed at 6, 12, and 18 months after surgery. All goats received splitting of bilateral mandibular outer cortex and interpositional grafting with natural coral and CHA, respectively (sandwich osteotomy). Data were evaluated and statistically analyzed by t-test.

RESULTS

All goats were observed at 3 different time points. The computed tomography images show that the area of operation was healed and the thickness of the mandible was increased in 3 time points. In the 3 groups, mandibular thickness and volume were significantly different compared with those before operation (P < 0.05). The volume of CHA group improved better than coral group (P < 0.05).

CONCLUSION

This study provides a promising alternative method for mandibular augmentation with a sandwich osteotomy and interpositional grafting with natural coral and CHA. The thickness and volume of mandible had been effectively increased in follow-ups.

Long term follow-up of titanium implants installed in block-grafted areas: A systematic review

BACKGROUND

An enduring clinical question concerns the outcome (ie, success) of implants placed in areas grafted with block-grafts.

OBJECTIVE

To undertake a systematic review of the literature on the long term results (≥5 years) of implants placed in maxillofacial areas grafted with any type of osseous block-grafts in two-stage surgeries. Further, the review addresses how available success criteria were used within the studies.

MATERIALS AND METHODS

The MEDLINE (PubMed) and EMBASE bibliographic databases were searched up to March 2017 for studies evaluating the long term results of implants placed in grafted areas. The search strategy was restricted to English language publications using combined terms which referred to the treatment method (implants placed in areas grafted with bone blocks), and follow-up characteristics (≥5 years and assessment of at least one parameter related to implant success criteria). To qualify for inclusion, studies should present outcome measurements indicating the success (or at least the survival) of the implants.

RESULTS

The search strategy yielded 17 studies, which were included in this systematic review. These studies presented survival rates ranging from 88.7% (after 15 years follow-up) to 98.7% (after 5 years follow-up). Five studies presented data based on predefined success criteria with success rates ranging from 86.8% to 100%. In these studies, the term "success" was often not properly defined.

CONCLUSION

The long term survival (≥5 years) of implants placed into block-grafted areas in two-stage surgeries was not lower than 75%, while success rates ranged from 86.8% to 100%. Although it was possible to identify published success criteria for implant follow-up, there is no broad consensus on how to report implant success in a consistent manner.

Onlay grafting with bovine bone mineral block for horizontal reconstruction of severely atrophic alveolar ridges in anterior maxillae: A 6-year prospective study

PURPOSE

The aim of this prospective study was to evaluate the efficacy and long-term outcomes of onlay grafting with bovine bone mineral block for reconstruction of horizontal alveolar ridge defects in anterior maxillae.

MATERIALS AND METHODS

Fourteen patients requiring rehabilitation of edentulous anterior maxillae were enrolled to receive onlay grafting in two layers. A cortical block harvested from the lateral aspect of the mandibular ramus was split to acquire approximately 1-mm-thick bone laminae. The cortical bone plate and block graft were compressed and fixed to the recipient sites. After 6 months, the width of the augmentation was recorded, and implants were inserted. Provisional and definitive prostheses were delivered 3 and a further 6 months later. Implant success and associated complications were assessed.

RESULTS

The horizontal bone gain was 8.73 ± 0.82, with a resorption rate of 7.03%. Severe bone resorption was noticed 6 months and 2 years after loading. Fistula occurred with the nonintegrated bovine block on the labial sides of the augmented sites 6 years after loading.

CONCLUSION

Onlay grafting with bovine bone mineral block in the anterior maxilla may yield optimal horizontal gain with low resorption rates, under the condition of at least 6 months' healing time, mixation with autogenous particulate bone, and application of a membrane to cover the graft site.

Block iliac bone grafting enhances osseous healing of alveolar reconstruction in older cleft patients: A radiological and histological evaluation

Background

Older alveolar cleft patients (&12 years old) often have wide bone defect as well as teeth loss, resulting in poor osseous healing with conventional alveolar bone grafting (ABG). In this study, we investigated a surgical technique of block iliac bone grafting for the alveolar cleft reconstruction and evaluated the clinical and radiological outcomes of these cleft patients.

Material and Methods

Fifteen patients were included in this study. All cases received preoperative cone bean computed tomography (CBCT) scans for the alveolar cleft evaluation. Osseous outcomes of block iliac bone grafting were assessed at 1 week, 3- and 6-month postoperatively. Volume changes and bone resorption rates were calculated using the measurement modules of Simplant software. Bone samples from one patient undergoing dental implantation were assessed by micro-CT and histological examination. The morbidities of donor-site were analyzed by clinical examination and questionnaire survey.

Results

The average age of the case series was 18.53±2.50 years. The intraoral incision of thirteen cases healed well. However, two cases had oronasal fistula and graft exposure at 1-week postoperatively. The results of follow-up CBCT scans showed significant resistance to radiation on both sides of the bone graft, suggesting a good osseous healing and new bone formation. The mean residual bone volume was 1.68±0.26 cm3, 1.29±0.23 cm3 and 1.15±0.23 cm3 at 1-week, 3- and 6-month postoperatively. Correspondingly, the mean bone resorption rates in 3- and 6-month postoperative were 21.78±6.88% and 30.66±8.97%, respectively. From micro-CT and HE examinations, the block bone samples exhibited a cancellous structure in which mature bone trabecula and functional blood vessels appeared. The average scores of donor-site morbidities were drastically decreased at 3- and 6-month postoperatively compared with those at 1-week postoperatively.

Conclusions

Our results demonstrated that block iliac bone grafting could achieve satisfying osseous outcomes in older alveolar cleft patients, and this technique provided favorable bony condition for further treatments, especially dental implantation.

Key words:Alveolar bone grafting, Block bone grafting, Osseous healing, CBCT.

Efficacy of the split-thickness labial flap method for soft tissue management in anterior ridge horizontal augmentation procedures: A clinical prospective study in the anterior maxilla

OBJECTIVE

To introduce a novel method of split-thickness labial flap in maxillary anterior ridge horizontal augmentation and to evaluate its efficacy and morbidity.

MATERIALS AND METHODS

230 patients were selected to receive either particulate or onlay grafting. A split-thickness labial flap was applied to cover the grafted area and close the wound. The incidence of postsurgical complications and the level of patient discomfort were evaluated. A visual analog scale was used to quantify the amount of pain and swelling in the patients.

RESULTS

In all 375 surgical sites, passive primary closure was achieved with the split-thickness labial flap method. Membrane exposure after surgery was seen in 6 cases in the onlay group and in 4 in the particulate group. No long-lasting pain (>1 week), paresthesia, or signs of infection occurred during the follow-up period of 6 months. The mean pain and swelling scores in the particulate graft group (2.75 ± 3.01 and 2.02 ± 2.51, respectively) were lower than the scores in the onlay graft group (3.18 ± 2.79 and 3.85 ± 2.25, respectively).

CONCLUSIONS

The flap advancement technique presented in this study facilitates clinically passive primary closure. This technique can be used successfully in both particulate and onlay horizontal graft procedures.

Comparison between peri-implant bone level changes of implants placed during and 3 months after iliac bone grafting

OBJECTIVE

The aim of this study was to compare the peri-implant bone level changes of implants placed during and 3 months after bone grafting from the iliac crest.

STUDY DESIGN

A total of 103 implants were placed: 42 during the grafting and 61 at 3 months after the grafting procedure. All patients were grafted with iliac bone from the anterosuperior iliac crest. Bone resorption was evaluated with cone beam computed tomography in all patients at their last control visit. Periodontal health was assessed via the gingival and plaque indices and pocket depths around the dental implants.

RESULTS

Mean bone resorption values at the buccal, lingual, mesial, and distal sides of the implants were 1.08 mm, 0.36 mm, 0.30 mm, and 0.25 mm, respectively, in the delayed group, and 1.87 mm, 1.25 mm, 0.92 mm, and 1.23 mm, respectively, in the simultaneous group; the differences between the groups were significant. There were no significant between-group differences in the gingival or plaque indices or pocket depths. The mean follow-up period was 29 months.

CONCLUSIONS

For reconstructing atrophic jaws, bone grafting from the iliac crest and implant placement after 3 months is a reliable technique with a high success rate and less bone resorption.

Novel expandable short dental implants in situations with reduced vertical bone height-technical note and first results

PURPOSE

Short implants often have the disadvantage of reduced primary stability. The present study was conducted to evaluate the feasibility and safety of a new expandable short dental implant system intended to increase primary stability.

METHODS

As a "proof of concept", a prospective clinical cohort study was designed to investigate intraoperative handling, primary and secondary implant stability (resonance frequency analysis), crestal bone changes, implant survival and implant success, of an innovative short expandable screw implant. From 2014 until 2015, 9 patients (7-9-mm vertical bone height) with 30 implants (length 5-7 mm, diameter 3.75-4.1 mm) were recruited consecutively.

RESULTS

All 30 implants in the 9 patients (age 44 to 80 years) could be inserted and expanded without intraoperative problems. Over the 3-year follow-up period, the implant success rate was 28/30 (93.3%). The mean implant stability quotients (ISQ) were as follows: primary stability, 69.7 ± 10.3 ISQ units, and secondary stability, 69.8 ± 10.2 ISQ units (p = 0.780), both without significant differences between the maxilla and mandible (p ≥ 0.780). The mean crestal bone changes after loading were (each measured from the baseline) as follows: in the first year, 1.0 ± 0.9 mm in the maxilla and 0.7 ± 0.4 mm in the mandible, and in the second year, 1.3 ± 0.8 mm and 1.0 ± 0.7 mm, respectively.

CONCLUSIONS

Compared to other prospective studies, in this indication, the success rate is acceptable. Implant stability shows high initial and secondary stability values. The system might present an extension of functional rehabilitation to the group of elderly patients with limited vertical bone height. Further long-term investigations should directly compare this compressive implant with standard short implants.

Long-Term Effect of Surface Roughness and Patients' Factors on Crestal Bone Loss at Dental Implants. A Systematic Review and Meta-Analysis

Publications from 2011 to 2015 were selected to evaluate effect of implant surface roughness on long-term bone loss as surrogate for peri-implantitis risk. 87 out of 2,566 papers reported the mean bone loss after at least 5 years of function. Estimation of the proportion of implants with bone loss above 1, 2, and 3 mm as well as analysis the effect of implant surface roughness, smoking, and history of periodontitis was performed. By means of the provided statistical information of bone loss (mean and standard deviation) the prevalence of implants with bone loss ranging from 1 to 3 mm was estimated. The bone loss was used as a surrogate parameter for "peri-implantitis" given the fact that "peri-implantitis" prevalence was not reported in most studies or when reported, the diagnostic criteria were unclear or of dubious quality. The outcome of this review suggests that peri-implant bone loss around minimally rough implant systems was statistically significant less in comparison to the moderately rough and rough implant systems. No statistically significant difference was observed between moderately rough and rough implant systems. The studies that compared implants with comparable design and different surface roughness, showed less average peri-implant bone loss around the less rough surfaces in the meta-analysis. However, due to the heterogeneity of the papers and the multifactorial cause for bone loss, the impact of surface roughness alone seems rather limited and of minimal clinical importance. Irrespective of surface topography or implant brand, the average weighted implant survival rate was 97.3% after 5 years or more of loading. If considering 3 mm bone loss after at least 5 years to represent the presence of "peri-implantitis," less than 5% of the implants were affected. The meta-analysis indicated that periodontal history and smoking habits yielded more bone loss.

Retrospective evaluation of 211 patients with maxillofacial reconstruction using parietal bone graft for implants insertion

PURPOSE

For a century, autologous bone grafts have been used in maxillofacial reconstruction. The ideal bone harvest site and grafting procedure remains a point of contention in regards to obtaining optimal long-term results with sufficient bone quantity and density without serious complications. More recently, confronted with growing patient requests and biomaterials development, maxillofacial surgeons and dentists have been considering these issues as they relate to pre-implant surgery. This study sought to evaluate implant success rate and complications following pre-implant surgery with parietal bone grafting.

MATERIALS AND METHODS

A retrospective study was carried out on patients who underwent maxillofacial reconstruction of different sites (symphysis, mandibular corpus, maxillary sinus and premaxilla) for the purpose of implant insertion.

RESULTS

311 procedures in 211 patients were included. The implant osseointegration rate was around 95%. Clinical follow-up ranged from 10 months to 11 years. A secondary procedure was performed in 6.1% of cases and we noted no serious complications at the harvest site.

DISCUSSION

With good revascularization and osseointegration of the graft, the use of parietal bone leads to an implant success rate similar to that seen in the literature. Moreover, the use of this material results in few infections and low bone resorption provided there is strict immobilization of the graft and no tension on the soft tissue sutures.

CONCLUSION

Parietal bone grafts technique possess the required qualities for the success of implant surgery, offering results at least as interesting as others using autogenous bone and with no serious complications on donor site.

Implant-Supported Immediately Loaded Fixed Full-Arch Dentures: Evaluation of Implant Survival Rates in a Case Cohort of up to 7 Years

BACKGROUND

The treatment of severely atrophied and edentulous jaws by means of fixed implant supported solutions is a challenging procedure.

PURPOSE

The immediate loading of four to six axial and tilted implants offers the possibility to overcome elaborate hard tissue augmentation procedures but lacks implant and patient related data on implant survival rates.

MATERIALS AND METHODS

This retrospective 7-years clinical trial investigated the implant survival rates of 2,081 implants (380 patients, 482 jaws) using an immediate loading protocol with either 4, 5, or 6 implants per restoration. Survival rates were calculated concerning implantation related factors (jaws/number of supporting implants/angulations/diameters/lengths) and patient related factors (medical status/smoking).

RESULTS

Overall survival of 2,081 implants was 97.0% on implant level. Survival rates of implantation related factors did not yield significant differences. Significant differences were yield between healthy patients and patients with osteoporosis (p = .002) and the medical status group "other" (p = .032), respectively. Smokers yielded a significantly higher survival than nonsmokers (p = .002).

CONCLUSIONS

It is assumed that four implants per jaw serve as a sufficient implant number for full arch restorations in both, the mandible and the maxilla. Osteoporosis under the medication with bisphosphonates seems to be a risk factor for implant survival. The authors suggest that the effect of smoking on ISRs remains controversial within this treatment concept.

Retrospective long-term analysis of bone level changes after horizontal alveolar crest reconstruction with autologous bone grafts harvested from the posterior region of the mandible

Purpose

The goal of this study was to evaluate the long-term success of horizontal alveolar crest augmentation of the retromolar region of the mandible with particulated bone, as well as factors affecting subsequent peri-implant bone loss.

Methods

A total of 109 patients (68 female, 41 male) suffering from alveolar ridge deficiencies of the maxilla and mandible were included in this study. All patients were treated with particulated retromolar bone grafts from the mandible prior to the insertion of endosseous dental implants. Mesial and distal peri-implant crestal bone changes were assessed at six time points. Several parameters, including implant survival and the influence of age, gender, localisation of the implant, diameter, covering procedures, and time points of implant placement, were analysed to identify associations with bone level changes using the Mann-Whitney U-test, the Kruskal-Wallis test, and Spearman's rank-order correlation coefficient.

Results

A total of 164 dental implants were placed in the maxilla (n=97) and in the mandible (n=67). The mean observation period was 105.26±21.58 months after implantation. The overall survival rate was 97.6% after 10 years. Overall, peri-implant bone loss was highest during the first year, but decreased over time. The mean amount of bone loss after 10 years was 2.47 mm mesially and 2.50 mm distally. Bone loss was significantly influenced by implant type and primary stability.

Conclusions

The use of particulated autologous retromolar bone grafts is a reliable technique for the horizontal reconstruction of local alveolar ridge deficiencies. Our results demonstrate that implants placed in augmented bone demonstrated similar bone level changes compared to implants inserted in non-augmented regions.