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

Quantum dots for bone tissue engineering

In confronting the global prevalence of bone-related disorders, bone tissue engineering (BTE) has developed into a critical discipline, seeking innovative materials to revolutionize treatment paradigms. Quantum dots (QDs), nanoscale semiconductor particles with tunable optical properties, are at the cutting edge of improving bone regeneration. This comprehensive review delves into the multifaceted roles that QDs play within the realm of BTE, emphasizing their potential to not only revolutionize imaging but also to osteogenesis, drug delivery, antimicrobial strategies and phototherapy. The customizable nature of QDs, attributed to their size-dependent optical and electronic properties, has been leveraged to develop precise imaging modalities, enabling the visualization of bone growth and scaffold integration at an unprecedented resolution. Their nanoscopic scale facilitates targeted drug delivery systems, ensuring the localized release of therapeutics. QDs also possess the potential to combat infections at bone defect sites, preventing and improving bacterial infections. Additionally, they can be used in phototherapy to stimulate important bone repair processes and work well with the immune system to improve the overall healing environment. In combination with current trendy artificial intelligence (AI) technology, the development of bone organoids can also be combined with QDs. While QDs demonstrate considerable promise in BTE, the transition from laboratory research to clinical application is fraught with challenges. Concerns regarding the biocompatibility, long-term stability of QDs within the biological environment, and the cost-effectiveness of their production pose significant hurdles to their clinical adoption. This review summarizes the potential of QDs in BTE and highlights the challenges that lie ahead. By overcoming these obstacles, more effective, efficient, and personalized bone regeneration strategies will emerge, offering new hope for patients suffering from debilitating bone diseases.

A novel approach for horizontal augmentation with split box: A method that combines split bone block and ridge split techniques

PURPOSE

The aim of this study was to investigate the effectiveness of the split-box technique, a novel technique that combines the ridge splitting and split bone block techniques.

MATERIALS AND METHODS

In this retrospective study, alveolar ridge defects were grafted using the split-box technique and its modifications, reverse split box and sliding split box. To determine horizontal changes in the alveolar bone, thickness was measured at two levels: crest width (CW) and screw level width (SLW). Alveolar ridge height (ARH) was also measured to detect a possible loss of vertical dimension. Measurements were performed using cone-beam computed tomography taken before the operation (T0) and at five months after the operation (T1).

RESULTS

Of a total of 41 patients included, 21 were females and 20 were males with a mean age of 44.5 ± 13.3 years. A total of 64 regions were augmented. Among the augmented regions, split-box technique was used in 31 regions, reverse split-box technique was used in 14 regions, and sliding split-box technique was used in 19 regions. The increase at the SLW, CW and the decrease in ARH from T0 to T1 was statistically significant (p < 0.005). A significant difference was found between split box and its modifications in terms of bone gain at the screw level, and the sliding box technique was associated with more bone gain than the other two methods (p < 0.05).

CONCLUSIONS

Split-box technique provides a comparable net gain in the alveolar crest width with lower complication risk than ridge split technique and lower postoperative morbidity than split bone block technique.

Comparison of morbidity-related parameters between autologous and allogeneic bone grafts for alveolar ridge augmentation from patients' perspective-A questionnaire-based cohort study

INTRODUCTION

Alveolar ridge augmentation is often required before dental implant placement. In this context, autologous bone grafts are considered the biological gold standard. Still, bone block harvesting is accompanied by some serious potential disadvantages and possible complications, such as pain, bleeding, and nerve irritation. Several studies aimed to compare autologous to allogeneic bone grafts concerning bone quality and implant survival rates; this is the first prospective study analyzing and comparing morbidity-related parameters after alveolar ridge augmentation using autogenous and allogeneic bone blocks from patients' perspective.

METHODS

Using a questionnaire, 36 patients were asked to evaluate the surgery as well as the post-operative period concerning pain, stress, sensibility deficits, satisfaction with, and consequences from the surgery as well as the preferred procedure for future alveolar ridge augmentations.

RESULTS

No significant differences were shown regarding stress and pain during and after surgery, whereas the rate of nerve irritations was twice as high in the autologous group. The swelling was significantly higher in patients with autologous bone blocks (p = 0.001). Nevertheless, the overall satisfaction of patients of both groups was very high, with over 8/10 points.

CONCLUSIONS

The swelling was the main reason for patients' discomfort in both groups and was significantly higher after autologous bone augmentation. Since this side effect seems to be a highly relevant factor for patients' comfort and satisfaction, it needs to be discussed during preoperative consultation to allow shared decision-making considering the anticipated morbidity.

Evaluation of the Success of Autogenous Block Grafting in Atrophic Maxillary and Mandibular Ridges Prior to and After Implant Placement

BACKGROUND

Dental implantology's success relies on adequate bone volume and quality, necessitating bone augmentation for implant placement. Primary lateral bone augmentation, utilizing autogenous block grafts, addresses horizontal bone loss.

OBJECTIVE

This study aims to evaluate the efficacy of autogenous block grafting, specifically ramus and fibula blocks, in addressing severe atrophic ridges before and after implant placement.

METHODS

Twenty-one patients underwent block grafting, predominantly using the ramus technique (80/20 ratio). CBCT measurements assessed horizontal grafting outcomes. Implant success and bone volume changes were analyzed.

RESULTS

Post-grafting, bone width increased from 1.8-3.1 mm to 4.5-6 mm, exceeding critical thresholds. Implant success reached 95%, indicating the grafting techniques' effectiveness.

CONCLUSION

Autogenous block grafting, especially with ramus and fibula blocks, transforms severe atrophic ridges, enabling successful implant integration. Long-term follow-up is essential for a comprehensive evaluation.

CLINICAL RELEVANCE

This study provides crucial insights into autogenous block grafting's transformative impact on challenging cases, guiding future applications in reconstructive dentistry.

Meta-analysis of application of autogenous dentin for alveolar ridge augmentation

OBJECTIVES

This investigation aimed to systematically evaluate the efficacy and safety of applying autogenous dentin (ATD) in alveolar ridge augmentation.

METHODS

The PubMed, Embase, Web of Science, Cochrane Library, CNKI, and Wanfang databases were electronically searched from January 1, 2010 to March 19, 2022 to identify clinical trials and cohort studies that employed ATD in alveolar ridge augmentation. The Cochrane Tool and the Newcastle-Ottawa Scale were employed to assess the risk of bias in randomized controlled trials and cohort studies, respectively. Data were analyzed via RevMan 5.4 software.

RESULTS

A total of 10 studies were included, 5 of which compared ATD with autologous bone and 5 with deproteinized bovine bone matrix (DBBM). Meta-analysis indicated that ATD had preferable performance [MD=2.01, 95% confidence interval (CI) (1.09, 2.93), P<0.000 1] in horizontal ridge augmentation compared with autologous bone but similar effect in vertical ridge augmentation [MD=-0.06, 95%CI (-0.21, 0.08), P=0.39] at 6 months after alveolar ridge augmentation. In terms of material absorption, ATD was significantly less than autologous bone or DBBM [MD=-0.59, 95%CI (-1.03, -0.15), P=0.008; MD=-0.63, 95%CI (-1.18, -0.07), P=0.03], but no significant difference in implant stability quotient and postoperative complications was observed [MD=-0.76, 95%CI (-3.04, 1.52), P=0.51; RR=1.01, 95%CI (0.33, 3.12), P=0.98].

CONCLUSIONS

ATD, as a bone grafted material for alveolar ridge augmentation, not only achieves similar or better bone incremental performance than autologous bone or DBBM but also has less absorption. However, further evidence from clinical trials with larger samples, higher quality, and longer follow-up period are needed to evaluate its superiority.

Survival Rates of Dental Implants in Autogenous and Allogeneic Bone Blocks: A Systematic Review

Background and Objectives: Preliminary studies emphasize the similar performance of autogenous bone blocks (AUBBs) and allogeneic bone blocks (ALBBs) in pre-implant surgery; however, most of these studies include limited subjects or hold a low level of evidence. The purpose of this review is to test the hypothesis of indifferent implant survival rates (ISRs) in AUBB and ALBB and determine the impact of various material-, surgery- and patient-related confounders and predictors. Materials and Methods: The national library of medicine (MEDLINE), Excerpta Medica database (EMBASE) and Cochrane Central Register of Controlled Trials (CENTRAL) were screened for studies reporting the ISRs of implants placed in AUBB and ALBB with ≥10 participants followed for ≥12 months from January 1995 to November 2021. The review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The risk of bias was assessed via several scoring tools, dependent on the study design. Means of sub-entities were presented as violin plots. Results: An electronic data search resulted in the identification of 9233 articles, of which 100 were included in the quantitative analysis. No significant difference (p = 0.54) was found between the ISR of AUBB (96.23 ± 5.27%; range: 75% to 100%; 2195 subjects, 6861 implants) and that of ALBB (97.66 ± 2.68%; range: 90.1% to 100%; 1202 subjects, 3434 implants). The ISR in AUBB was increased in blocks from intraoral as compared to extraoral donor sites (p = 0.0003), partially edentulous as compared to totally edentulous (p = 0.0002), as well as in patients younger than 45 as compared to those older (p = 0.044), cortical as compared to cortico-cancellous blocks (p = 0.005) and in delayed implantations within three months as compared to immediate implantations (p = 0.018). The ISR of ALBB was significantly increased in processed as compared to fresh-frozen ALBB (p = 0.004), but also in horizontal as compared to vertical augmentations (p = 0.009). Conclusions: The present findings widely emphasize the feasibility of achieving similar ISRs with AUBB and ALBB applied for pre-implant bone grafting. ISRs were negatively affected in sub-entities linked to more extensive augmentation procedures such as bone donor site and dentition status. The inclusion and pooling of literature with a low level of evidence, the absence of randomized controlled clinical trials (RCTs) comparing AUBB and ALBB and the limited count of comparative studies with short follow-ups increases the risk of bias and complicates data interpretation. Consequently, further long-term comparative studies are needed.

Recycled Porcine Bone Powder as Filler in Thermoplastic Composite Materials Enriched with Chitosan for a Bone Scaffold Application

This work aims to synthesize biocompatible composite materials loaded with recycled porcine bone powder (BP) to fabricate scaffolds for in-situ reconstruction of bone structures. Polylactic acid (PLA) and poly(ε-caprolactone) (PCL) were tested as matrices in percentages from 40 wt% to 80 wt%. Chitosan (CS) was selected for its antibacterial properties, in the amount from 5 wt% to 15 wt%, and BP from 20 wt% to 50 wt% as active filler to promote osseointegration. In this preliminary investigation, samples have been produced by solvent casting to introduce the highest possible percentage of fillers. PCL has been chosen as a matrix due to its greater ability to incorporate fillers, ensuring their adequate dispersion and lower working temperatures compared to PLA. Tensile tests demonstrated strength properties (6–10 MPa) suitable for hard tissue engineering applications. Based on the different findings (integration of PLA in the composite system, improvements in CS adhesion and mechanical properties), the authors supposed an optimization of the synthesis process, focused on the possible implementation of the electrospinning technique to develop PCL-BP composites reinforced with PLA-CS microfibers. Finally, biological tests were conducted to evaluate the antibacterial activity of CS, demonstrating the applicability of the materials for the biomedical field.

Horizontal Ridge Augmentation: A Comparison between Khoury and Urban Technique

PURPOSE

The objective of this systematic review was to evaluate and compare the clinical efficacy of horizontal alveolar ridge augmentation techniques described by Khoury and Urban.

METHODS

A systematic electronic search in the MEDLINE databases, SCOPUS, WOS, and the Cochrane Central Register of Controlled Trials (CENTRAL) as well as a manual search, were conducted independently by two reviewers up to July 2021.

RESULTS

Six studies met the pre-established inclusion criteria and were included in the descriptive analysis. Due to the heterogeneity found across the included studies, meta-analysis could not be performed. Horizontal bone gain was between 3.93 ± 0.9 mm and 5.02 ± 0.8 mm with the Khoury technique and between 3.9 ± 0.9 mm and 5.68 ± 1.42 mm with the Urban technique. Similar complication rates were reported in both groups: infection (7%), in the Khoury technique, and membrane exposure (3.2-13.6%), in the Urban technique, being the most frequent events.

CONCLUSIONS

Both techniques were found to be effective, in terms of clinical bone gain, for horizontal alveolar ridge gain. Nevertheless, available literature is limited, and there is a lack of comparative studies to better evaluate the results.

Performance of Nano-Hydroxyapatite/Beta-Tricalcium Phosphate and Xenogenic Hydroxyapatite on Bone Regeneration in Rat Calvarial Defects: Histomorphometric, Immunohistochemical and Ultrastructural Analysis

Background

Synthetic biomaterials have played an increasingly prominent role in the substitution of naturally derived biomaterials in current surgery practice. In vitro and in vivo characterization studies of new synthetic biomaterials are essential to analyze their physicochemical properties and the underlying mechanisms associated with the modulation of the inflammatory process and bone healing.

Purpose

This study compares the in vivo tissue behavior of a synthetic biomaterial nano-hydroxyapatite/beta-tricalcium phosphate (nano-HA/ß-TCP mixture) and deproteinized bovine bone mineral (DBBM) in a rat calvarial defect model. The innovation of this work is in the comparative analysis of the effect of new synthetic and commercially xenogenic biomaterials on the inflammatory response, bone matrix gain, and stimulation of osteoclastogenesis and osteoblastogenesis.

Methods

Both biomaterials were inserted in rat defects. The animals were divided into three groups, in which calvarial defects were filled with xenogenic biomaterials (group 1) and synthetic biomaterials (group 2), or left unfilled (group 3, controls). Sixty days after calvarial bone defects filled with biomaterials, periodic acid Schiff (PAS) and Masson’s trichrome staining, immunohistochemistry tumor necrosis factor-alpha (TNF-α), matrix metalloproteinase-9 (MMP-9), and electron microscopy analyses were conducted.

Results

Histomorphometric analysis revealed powerful effects such as a higher amount of proteinaceous matrix and higher levels of TNF-α and MMP-9 in bone defects treated with alloplastic nano-HA/ß-TCP mixture than xenogenicxenogic biomaterial, as well as collagen-proteinaceous material in association with hydroxyapatite crystalloids.

Conclusion

These data indicate that the synthetic nano-HA/ß-TCP mixture enhanced bone formation/remodeling in rat calvarial bone defects. The nano-HA/ß-TCP did not present risks of cross-infection/disease transmission. The synthetic nano-hydroxyapatite/beta-tricalcium phosphate mixture presented adequate properties for guided bone regeneration and guided tissue regeneration for dental surgical procedures.

Effectiveness of the bone ring technique and simultaneous implant placement for vertical ridge augmentation: a systematic review

Background

Dimensional changes after dental extraction frequently lead to situations in which bone augmentation procedures are required prior to dental implant placement. Bone ring technique (BRT) has been described as a one-stage approach to restore vertical alveolar ridge defects, in which an autogenous or allogeneic cortico-cancellous bone block graft is stabilized with a dental implant inserted simultaneously. The objective of this systematic review was to evaluate the clinical performance of BRT.

Materials and methods

This review was conducted according to PRISMA guidelines. An electronic search was conducted in four databases: (1) The National Library of Medicine (MEDLINE/PubMed) via Ovid; (2) Web of Science (WOS); (3) SCOPUS; and (4) Cochrane Central Register of Controlled Trials (CENTRAL). The Newcastle-Ottawa Quality Assessment Scale and The Joanna Briggs Institute Critical Appraisal tool were used to assess the quality of evidence in the studies reviewed.

Results

Sixteen studies with a total of 186 patients treated with 219 bone rings bocks were included in the review. The studies showed a mean bone gain of 4.94 mm, mean bone resorption of 0.83 mm, and mean marginal bone loss of 0.57 mm after a mean follow-up period of 13.35 months. A mean bone ring survival rate of 97.26% and implant survival rate of 94.97% were recorded.

Conclusions

BRT would appear to be an adequate alternative technique for restoring single vertical alveolar ridge defects with simultaneous dental implant placement. However, further studies comparing this technique with other vertical ridge augmentation procedures in different clinical scenarios are needed to confirm the present results.