Bone Regeneration Around Implants Using Spherical and Granular Forms of Bioactive Glass Particles

Bioactive Inorganic Materials for Dental Applications: A Narrative Review

Over time, much attention has been given to the use of bioceramics for biomedical applications; however, the recent trend has been gaining traction to apply these materials for dental restorations. The bioceramics (mainly bioactive) are exceptionally biocompatible and possess excellent bioactive and biological properties due to their similar chemical composition to human hard tissues. However, concern has been noticed related to their mechanical properties. All dental materials based on bioactive materials must be biocompatible, long-lasting, mechanically strong enough to bear the masticatory and functional load, wear-resistant, easily manipulated, and implanted. This review article presents the basic structure, properties, and dental applications of different bioactive materials i.e., amorphous calcium phosphate, hydroxyapatite, tri-calcium phosphate, mono-calcium phosphate, calcium silicate, and bioactive glass. The advantageous properties and limitations of these materials are also discussed. In the end, future directions and proposals are given to improve the physical and mechanical properties of bioactive materials-based dental materials.

Three-dimensional volumetric changes of 5 different bone grafts in human maxillary sinuses reconstruction: a randomized clinical study

PURPOSE

This study aimed to compare the three-dimensional volumetric changes of human maxillary sinuses after reconstruction using 5 different bone grafts.

PATIENTS AND METHODS

Patients underwent unilateral maxillary sinus bone height reconstruction using 5 bone substitutes allocated in different groups as follows: group 1 was grafted with autogenous bone graft alone; group 2 with beta-tricalcium phosphate (β-TCP); group 3 with β-TCP + autogenous bone graft 1:1; group 4 with bioactive glass; and group 5 with bioactive glass + autogenous bone graft 1:1. The patients were submitted to cone beam computed tomography in two periods: 15 days after the surgical procedure (T1) and after 6 months (T2). The results were evaluated as the formula T2-T1 expressing the three-volumetric changes of the biomaterials in elapsed time.

RESULTS

The resorption rate of autogenous bone graft was -630.699 ± 300.9 mm³; in the β-TCP group, it was -315.772 ± 125.6 mm³; in the group with β-TCP + autogenous bone graft 1:1, it was -336.205 ± 195.7 mm³; and in groups with bioactive glass and with the addition of autogenous bone graft 1:1, it was -428.878 ± 311.6 mm³ and -576.917 ± 471.6 mm³, respectively, without statistical difference (p = 0.167). Pearson's correlated test revealed a strong correlation as well as a progressive resorption of the grafts during bone healing.

CONCLUSION

The similar outcomes for the three-dimensional volumetric changes using the bone substitutes evaluated after 6 months of bone healing suggest that all these grafts can be performed to maxillary sinus reconstruction.

Sonochemical time standardization for bioactive materials used in periimplantar defects filling

The aim of this study was determinate the best sonochemical time in order to obtain better bone characteristics when a bioactive material (Biogran) is used in the filling periimplantar defects. In this study, 32 rats were submitted to surgical proceedings to create a periimplantar defect that was filled with Biogran receiving different sonochemical times: 15 (G1), 30 (G2), 45 (G3) or 90 min (G4). The biomaterial was characterized through X-ray diffraction and scanning electron microscopy (SEM). In vivo analysis was performed through micro CT, laser confocal microscopy, immunohistochemistry and evaluation of bone cytoarchitecture through hematoxylin and eosin (HE) staining. The data were submitted to statistical testing, considering a significance level of p < 0.05. Rx diffraction of pure bioglass showed that it is predominantly amorphous; otherwise, there are small peaks at 23° and 31°. SEM shows that the longer the sonochemical time, the less edges the biomaterial will present. Within the groups, G1 and G2 showed the best quantity and quality by micro CT (p > 0.05). The best bone turnover result was found in G1 and G2, otherwise the better results were related to neoformed bone area, bone mineral apposition rate and bone implant contact to G1 (p < 0.05). G1 had the best results in terms of bone cytoarchitectural evaluation and immunohistochemistry. It is possible to conclude that Biogran that received 15 min of sonochemical treatment (G1) presented periimplantar bone repair with the best extracellular matrix properties, including the best quality and quantity of vital bone.

Histomorphometric and immunohistochemical assessment of RUNX2 and VEGF of Biogran™ and autogenous bone graft in human maxillary sinus bone augmentation: A prospective and randomized study

BACKGROUND

Few studies have been conducted to assess new bone formation using Biogran, a bioactive glass, in maxillary sinus bone augmentation through a prospective and randomized evaluation. Moreover, there are no studies that evaluate cellular behavior by immunohistochemical assessment for osteoblastic and vascular activity during bone repair.

PURPOSE

The aim of this study is to compare new bone formation and cellular behavior with Biogran alone, a 1:1 combination of Biogran and autogenous bone graft, and autogenous bone graft alone in human maxillary sinuses.

MATERIALS AND METHODS

Ten maxillary sinuses were grafted with Biogran (Group 1), 10 grafted with Biogran added to autogenous bone graft in a 1:1 ratio (Group 2), and 10 grafted with autogenous bone graft alone (Group 3). After 6 months of bone healing, samples were obtained concurrent to the dental implants' placement to be evaluated by histomorphometric and immunohistochemical assessment for RUNX2 and vascular endothelial growth factor (VEGF).

RESULTS

The amount of new bone formation in Group 1 was 42.0 ± 7.3% in the pristine bone region, 40.7 ± 14.0% in the intermediate region, and 45.6 ± 13.5% in apical region. In Group 2, for pristine bone, intermediate, and apical regions, new bone formation was 36.6 ± 12.9%, 33.2 ± 13.3%, and 45.8 ± 13.9%, respectively. Group 3 showed new bone formation of 37.3 ± 11.6%, 35.3 ± 14.7%, and 39.9 ± 15.8% in pristine bone, intermediate, and apical regions, respectively. The immunolabeling for RUNX2 showed low cellular activity in osteoblasts for all groups, and the VEGF assessment demonstrated moderate cellular activity in Groups 1 and 2; however, Group 3 presented with low activity in the pristine bone region, followed by moderate activity in the intermediate and apical region.

CONCLUSION

This study demonstrates that Biogran and its combination with autogenous bone graft 1:1 are good bone substitutes due to their similarity to autogenous bone graft.

Animal models for periodontal regeneration and peri-implant responses

Translation of experimental data to the clinical setting requires the safety and efficacy of such data to be confirmed in animal systems before application in humans. In dental research, the animal species used is dependent largely on the research question or on the disease model. Periodontal disease and, by analogy, peri-implant disease, are complex infections that result in a tissue-degrading inflammatory response. It is impossible to explore the complex pathogenesis of periodontitis or peri-implantitis using only reductionist in-vitro methods. Both the disease process and healing of the periodontal and peri-implant tissues can be studied in animals. Regeneration (after periodontal surgery), in response to various biologic materials with potential for tissue engineering, is a continuous process involving various types of tissue, including epithelia, connective tissues and alveolar bone. The same principles apply to peri-implant healing. Given the complexity of the biology, animal models are necessary and serve as the standard for successful translation of regenerative materials and dental implants to the clinical setting. Smaller species of animal are more convenient for disease-associated research, whereas larger animals are more appropriate for studies that target tissue healing as the anatomy of larger animals more closely resembles human dento-alveolar architecture. This review focuses on the animal models available for the study of regeneration in periodontal research and implantology; the advantages and disadvantages of each animal model; the interpretation of data acquired; and future perspectives of animal research, with a discussion of possible nonanimal alternatives. Power calculations in such studies are crucial in order to use a sample size that is large enough to generate statistically useful data, whilst, at the same time, small enough to prevent the unnecessary use of animals.

Treatment of an early failing implant by guided bone regeneration using resorbable collagen membrane and bioactive glass

Implant failure can be divided into early (prior to prosthetic treatment) or late (after prosthetic rehabilitation). Early failure is generally due to interference in the healing process after implant placement. Implants undergoing early failure will show progressive bone loss on radiographs during the healing period (4 to 6 weeks). In the present case report, early progressive bone loss was seen at 6 weeks, after placement of a non-submerged single piece mini implant. Clinical examination revealed peri-implant bleeding on probing and pocket and grade-1 mobility. Treatment protocol included mechanical debridement (plastic curettes), chemical detoxification with supersaturated solution of citric acid, antibiotics and guided bone regeneration therapy using the collagen membrane as guided bone regeneration barrier in combination with bioactive glass as bone grafting material. The 6 month postoperative examination showed complete resolution of the osseous defect, thus suggesting that this technique may hold promise in the treatment of implants undergoing early failure.

Systematic review of pre-clinical models assessing implant integration in locally compromised sites and/or systemically compromised animals

OBJECTIVE

The aim was to systematically search the dental literature for pre-clinical models assessing implant integration in locally compromised sites (part 1) and systemically compromised animals (part 2), and to evaluate the quality of reporting of included publications.

METHODS

A Medline search (1966-2011) was performed, complimented by additional hand searching. The quality of reporting of the included publications was evaluated using the 20 items of the ARRIVE (Animals in Research In Vivo Experiments) guidelines.

RESULTS

One-hundred and seventy-six (part 1; mean ARRIVE score = 15.6 ± 2.4) and 104 (part 2; 16.2 ± 1.9) studies met the inclusion criteria. The overall mean score for all included studies amounted to 15.8 ± 2.2. Housing (38.3%), allocation of animals (37.9%), numbers analysed (50%) and adverse events (51.4%) of the ARRIVE guidelines were the least reported. Statistically significant differences in mean ARRIVE scores were found depending on the publication date (p < 0.05), with the highest score of 16.7 ± 1.6 for studies published within the last 2 years.

CONCLUSIONS

A large number of studies met the inclusion criteria. The ARRIVE scores revealed heterogeneity and missing information for selected items in more than 50% of the publications. The quality of reporting shifted towards better-reported pre-clinical trials within recent years.

Bone healing in critical-size defects treated with new bioactive glass/calcium sulfate: a histologic and histometric study in rat calvaria

This study analyzed histologically the influence of new spherical bioactive glass (NBG) particles with or without a calcium sulfate (CS) barrier on bone healing in surgically created critical-size defects (CSD) in rat calvaria. A CSD was made in each calvarium of 60 rats, which were divided into three groups: C (control): the defect was filled with blood clot only; NBG: the defect was filled with NBG only; and NBG/CS: the defect was filled with NBG covered by CS barrier. Subgroups were euthanized at 4 or 12 weeks. Amounts of new bone and remnants of implanted materials were calculated as percentages of total area of the original defect. Data were statistically analyzed. In contrast to Group C, thickness throughout defects in Groups NBG and NBG/CS was similar to the original calvarium. At 4 weeks, Group C had significantly more bone formation than Group NBG/CS. No significant differences were found between Group NBG and either Group C or Group NBG/CS. At 12 weeks, Group C had significantly more bone formation than Group NBG or NBG/CS. NBG particles, used with or without a CS barrier, maintained volume and contour of area grafted in CSD. Presence of remaining NBG particles might have accounted for smaller amount of new bone in Groups NBG and NBG/CS at 12 weeks post-operative.