Chitosan scaffolds with mesoporous hydroxyapatite and mesoporous bioactive glass

Bone regeneration is one of the most well-known fields in tissue regeneration. The major focus concerns polymeric/ceramic composite scaffolds. In this work, several composite scaffolds based on chitosan (CH), with low and high molecular weights, and different concentrations of ceramics like mesoporous bioactive glass (MBG), mesoporous hydroxyapatite (MHAp) and both MBG and MHAp (MC) were produced by lyophilization. The purpose is to identify the best combination regarding optimal morphology and properties. The tests of the scaffolds present a highly porous structure with interconnected pores. The compression modulus increases with ceramic concentration in the scaffolds. Furthermore, the 75%MBG (835 ± 160 kPa) and 50%MC (1070 ± 205 kPa) samples are the ones that mostly enhance increases in mechanical properties. The swelling capacity increases with MBG and MC, respectively, to 700% and 900% and decreases to 400% when MHAp concentration increases. All scaffolds are non-cytotoxic at 12.5 mg/mL. The CHL scaffolds improve cell adhesion and proliferation compared to CHH, and the MC scaffold samples, show better results than those produced with just MBG or MHAp. The composite scaffolds of chitosan with MBG and MHAp, have revealed to be the best combination due to their enhanced performance in bone tissue engineering.

Platelet-rich fibrin as a tissue engineering material in accelerate bone healing in rat bone defects: A systematic review and meta-analysis

Introduction

Various techniques for tissue engineering have been introduced to help regenerate damaged or lost bone tissue. This study aimed to see the potential implication of platelet-rich fibrin (PRF) to accelerate the bone healing process in rat bone defects.

Methods

A systematic literature search was conducted from several electronic databases on subjects looking at the use of PRF in rat bone defects and their results in bone regeneration. Specific results compared PRF vs. other methods, PRF vs. control, and PRV vs. combination PRF and other methods. Science Direct, PubMed, and Cochrane Library were the main information sources. The Cochrane Collaboration method is employed to assess the risk of bias.

Results

A total of 483 rats were used in the twelve studies, and this meta-analysis showed that the PRF vs. other methods pooled odds ratio (OR) obtained was 0.92 (95% CI 0.42-2.04; p = 0.29; I² = 18%), PRF versus control OR obtained 9.45 (95% CI 4.68-19.08; P = 0.01; I² = 0%), the combination of PRF compared to PRF alone OR obtained 0.12 (95% CI 0.03-0.41; p = 0.01; I² = 0%).

Discussion

Platelet-rich fibrin accelerates the bone healing process in rat bone defects compared to physiologically. Platelet-rich fibrin combined with other methods can stimulate rat bone defects than utilization of platelet-rich fibrin only. The small number of articles assessed may cause limitations in sensitivity tests. This study was registered in the research registry (reviewregistry1341).

Review of the Pathways Involved in the Osteogenic Differentiation of Adipose-Derived Stem Cells

Grafts and prosthetic materials used for the repair of bone defects are often accompanied by comorbidity and rejection. Therefore, there is an immense need for novel approaches to combating the issues surrounding such defects. Because of their accessibility, substantial proportion, and osteogenic differentiation potential, adipose-derived stem cells (ASCs) make for an ideal source of bone tissue in regenerative medicine. However, efficient induction of ASCs toward an osteoblastic lineage in vivo is met with challenges, and many signaling pathways must come together to secure osteoblastogenesis. Among them are bone morphogenic protein, wingless-related integration site protein, Notch, Hedgehog, fibroblast growth factor, vascular endothelial growth factor, and extracellular regulated-signal kinase. The goal of this literature review is to conglomerate the present research on these pathways to formulate a better understanding of how ASCs are most effectively transformed into bone in the context of tissue engineering.

Bone regeneration in diabetic patients. A systematic review

Background

Oral bone regeneration techniques (OBRT) attempt to provide the appropriate bone volume and density to correctly accomplish dental implant treatments. The objective was to determine whether differences exist in the clinical outcomes of these techniques between diabetic and non-diabetic patients, considering the level of scientific evidence.

Material and Methods

A systematic review following PRISMA statements was conducted in the PubMed, Scopus and Cochrane databases with the search terms: “Diabetes Mellitus”, “guided bone regeneration”, “bone regeneration”, “alveolar ridge augmentation”, “ridge augmentation”, bone graft*, “sinus floor augmentation”, “sinus floor elevation”, “sinus lift”, implant*. Articles were limited to those published less than 10 years ago and in English. Inclusion criteria were: human studies of all bone regeneration techniques, including at least 10 patients and the using OBRT in diabetic and non-diabetic patients. Non-human studies were excluded. They were stratified according to their level of scientific evidence related to SORT criteria (Strength of Recommendation Taxonomy).

Results

The initial search provided 131 articles, after reading the abstracts a total of 33 relevant articles were selected to read the full text and analyzed to decide eligibility. Finally, seven of them accomplished the inclusion criteria: two controlled clinical trials, one cohort study and four case series.

Conclusions

A low grade of evidence regarding the use of OBRT in diabetic patients was found. The recommendation for this intervention in diabetic patients is considered type C due to the high heterogeneity of the type of diabetic patients included and the variability of the techniques applied.

Key words:Diabetes Mellitus, guided bone regeneration, bone regeneration.

Complications of augmentation procedures for dental implants in private practice, Victoria, Australia

PURPOSE

This study audited complications associated with augmentation for dental implants, retrospectively over a 5-year period in a variety of private dental practices in Victoria (Australia).

METHODS

Complications were categorized as surgical or biological and compared to a group not requiring augmentation. Implant factors underwent univariate and multivariate analysis.

RESULTS

The study assessed 8486 implants with 26.9% undergoing augmentation. Augmentation had no effect on implant survival, however, a significant increase in complications for those implants requiring augmentation was found (P = <0.001). The hard tissue augmented group had significantly more cases of insufficient bone/dehiscences at implant placement (P < 0.001), and post-placement bone loss (P = 0.0014). These implants were grafted simultaneously (P < 0.05) with particulate autogenous bone and/or Bio-Oss (P < 0.05) with resorbable xenograft membrane (P < 0.001). There was significantly more bone loss in open sinus lifted cases than implants placed in native bone (1.90% v 0.30%; P = 0.009).

CONCLUSIONS

The study demonstrated no increase in graft complications that could be related to any specific augmentation technique, suggesting that routine grafting procedures used in private practice were safe and appropriate. Previously augmented sites were found to be more likely to require further augmentation at implant placement.

Bone augmentation as an adjunct to dental implant rehabilitation in patients with diabetes mellitus: A review of literature

The aim of the present article is to review the success of bone augmentation performed as an adjunct to dental implant rehabilitation in patients with diabetes mellitus. A literature review was conducted in PubMed on this topic, which yielded a total of 102 publications. For inclusion, publications had to be human studies, written in English language and should report on the success of bone augmentation as an adjunct to dental implant rehabilitation in diabetic patients. After screening the titles and abstracts, 11 full texts publications were obtained, of which seven were included in the review. These studies provided data on various bone augmentation techniques such as sinus floor elevation (SFE), guided bone regeneration (GBR), and onlay bone grafting. Even though the current review revealed that there are not many studies reporting data relevant to the analyzed topic, the data obtained suggests that; (1) staged GBR technique should be considered more feasible and predictable for bone augmentation, (2) clinicians must take meticulous care when planning and conducting SFE, and (3) block bone augmentation technique should be avoided.

Effect of sex-hormone levels, sex, body mass index and other host factors on human craniofacial bone regeneration with bioactive tricalcium phosphate grafts

Little is known regarding the associations between sex-hormone levels, sex, body mass index (BMI), age, other host factors and biomaterial stimulated bone regeneration in the human craniofacial skeleton. The aim of this study was to elucidate the associations between these factors and bone formation after sinus floor augmentation procedures (SFA) utilizing a bioactive tricalcium phosphate (TCP) bone grafting material. We conducted a prospective study in a human population in which 60 male and 60 female participants underwent SFA and dental implant placement using a staged approach. BMI as well as levels of serum estradiol (E2), total testosterone (TT), and the free androgen index (FAI) were measured by radioimmunoassay and electrochemoluminescent-immunoassay. At implant placement, 6 months after SFA, bone biopsy specimens were harvested for hard tissue histology, the amount of bone formation was evaluated by histomorphometry and immunohistochemical analysis of osteogenic marker expression. The Wilcoxon rank-sum U test, Spearman correlations and linear regression analysis were used to explore the association between bone formation and BMI, hormonal and other host factors. BMI and log E2 were significantly positively associated with bone formation in male individuals (p < 0.05). Histomorphometry revealed trends toward greater bone formation and osteogenic marker expression with non-smokers compared to smokers. In male patients, higher E2 levels and higher BMI enhanced TCP stimulated craniofacial i.e. intramembranous bone repair.

Systematic analysis on the efficacy of bone enhancement methods used for success in dental implants

Bone grafting is beneficial in enhancing bones that are lost due to trauma or natural or pathologic process. Autogenous bone, allogenic bone, xenogeneic bone, bone substitutes, and alloplasts can also be used for this purpose. Bone quantity should be adequate for the placement of implants, which necessitate the use of bone grafts before implant placement.

OBJECTIVE

This review analyses the different bone graft materials that are used for grafting around implants and evaluate if these grafts yield successful implant osseointegration over a period of time.

MATERIALS AND METHODS

The MEDLINE-PubMed database was searched from September 2016 to 10 years previously. Several journals were hand searched and from cross-references. The primary outcome measure that was analyzed was the survival rate of dental implants in the grafted sites at 6 months-1 year, and the secondary outcomes were success rates of dental implants over a period of 3-5 years' follow-up.

RESULTS

The search yielded 213 articles. Ultimately, 31 studies meeting the eligibility criteria were selected. The analysis shows that autologous bone grafts can be preferred over allografts and xenografts for grafting implant sites, which showed less complication and high success rate.

CONCLUSION

Based on the available data in the current existing studies with a follow-up period of at least 3-5 years, it can be summarized that the autologous bone grafts can be preferred over allografts and xenografts for grafting implant sites since they are stable for at least 3-5 years.

Interactive 3D imaging technologies: application in advanced methods of jaw bone reconstruction using stem cells/pre-osteoblasts in oral surgery

Cone beam computed tomography has created a specific revolution in maxillofacial imaging, facilitating the transition of diagnosis from 2D to 3D, and expanded the role of imaging from diagnosis to the possibility of actual planning. There are many varieties of cone beam computed tomography-related software available, from basic DICOM viewers to very advanced planning modules, such as InVivo Anatomage, and SimPlant (Materialise Dental). Through the use of these programs scans can be processed into a three-dimensional high-quality simulation which enables planning of the overall treatment. In this article methods of visualization are demonstrated and compared, in the example of 2 cases of reconstruction of advanced jaw bone defects using tissue engineering. Advanced imaging methods allow one to plan a miniinvasive treatment, including assessment of the bone defect's shape and localization, planning a surgical approach and individual graft preparation.

Healing properties of implants inserted concomitantly with anorganic bovine bone. A histomorphometric human study

BACKGROUND

The present prospective, randomized, double-blind study evaluated the bone-forming process around implants inserted simultaneously with anorganic bovine bone (ABB) in sinus grafting.

METHODS

A total of 18 threaded mini-implants with Osseotite (O) and Nanotite (N) surfaces were placed in seven patients (nine sites). After 12 months, the implants were retrieved and processed for histological analysis. A total of 18 cutting and grinding sections were investigated with bright-field light microscopy, circularly polarized light microscopy (CPLM), confocal scanning laser microscope (CSLM), and scanning electron microscope (SEM) with energy dispersive spectrometer (EDS).

RESULTS

The bone-to-implant contact rate in native crestal bone was 62.6 ± 0.4% for N implants and 54.3 ± 0.5% for the O implants (p = 0.001). The collagen fibre density, as assessed by CPLM, was 79.8 ± 6.0 nm for the N group and 74.6 ± 4.6 nm for the O group (p < 0.05). Line scan EDS starting from ABB to newly formed bone showed a decrease in calcium content and an increase of carbon while phosphorus content was constant.

CONCLUSIONS

While the N surface improved the peri-implant endosseous healing properties in the native bone, when compared to the O surface, it did not improve the healing properties in the bone-graft area.