Osseoinductive elements around immediate implants for better osteointegration: a pilot study in foxhound dogs

In Vivo feature of the regenerative potential of chitosan and alginate based osteoplastic composites doped with calcium phosphates, zinc ions, and vitamin D2

PURPOSE

In vivo comparison of the regenerative potential of two calcium phosphate-biopolymer osteoplastic composites: а) based on alginate (Alg) and hydroxyapatite (HA) - Alg/HA/CS/Zn/D2, b) based on chitosan (CS) and brushite (DCPD) - CS/DCPD/D2.

MATERIALS AND METHODS

36 white male laboratory rats aged six months were used. A defect to the bone marrow canal in the middle of the femur diaphysis was made with a dental bur of 2 mm. The bone defect healed under the blood clot (control) in the different animal groups and was filled with Alg/HA/CS/Zn/D2 and CS/DCPD/D2. The regeneration of the bone defect was studied on the 30th, 90th, and 140th days by computer tomography (CT).

RESULTS

On the 30th day, all groups' implantation site optical density (OD) was significantly lower than that of the adjacent maternal bone (MB). Intensity of bone formation for Alg/HA/CS/Zn/D2 exceeds CS/DCPD/D2. On the 90th day, the bone trauma site OD with Alg/HA/CS/Zn/D2 (1725.4 ± 86 HU) and CS/DCPD/D2 (1484.9 ± 69 HU) exceeded the OD of the control (942.5 ± 55 HU). On the 140th day, the OD of Alg/HA/CS/Zn/D2 and CS/DCPD/D2 implantation sites was higher than Control and MB OD. Visually, the area of the past injury with the Alg/HA/CS/Zn/D2 could be detected only by the presence of an endosteal bone callus and in the case of CS/DCPD/D2 - by the shadow of the remaining biomaterial in the bone marrow canal.

CONCLUSIONS

According to CT data, Alg/HA/CS/Zn/D2 and CS/DCPD/D2 contribute to the complete healing of the femoral diaphysis defect in 140 days, but the regenerative potential of Alg/HA/CS/Zn/D2 from 30 days to 140 days is higher than CS/DCPD/D2 biomaterial.

Effect of zinc oxide micro- and nanoparticles on cytotoxicity, antimicrobial activity and mechanical properties of apatite-polymer osteoplastic material

This work is devoted to the comparison of the physical and biological properties of synthesized osteoplastic composites with an experimentally determined content (375 μg/g) of the micro (ZnOMPs) and nano (ZnONPs) particles, immobilized in Hydroxyapatite-Alginate-Chitosan matrix (HA-Alg-CS). ZnONPs show pronounced antimicrobial activity against E.coli ATCC 25922 and S. aureus ATCC 25923, while ZnOMPs only in the CS presence. Composites containing ZnONPs/MPs do not have a toxic effect on bone-forming cells - osteoblasts, preserving their ability to biomineralization. ZnOMPs and ZnONPs to varying degrees, but significantly affect composites' swelling, porosity, shape stability, and prolong vitamin D3 release for 120h, compared to Control. Composites do not demonstrate unwanted "burst release." ZnONPs/MPs increase Youngs' modulus of the HA-Alg matrix, namely 348 → 419 MPa (ZnOMPs), 348 → 646 MPa (ZnONPs), and weaken the plastic (irreversible) deformations. The compressive strength of HA-Alg and HA-Alg/CS matrixes containing ZnONPs (178 MPa and 251 MPa, respectively) is in the range of values for native cortical bone (170-193 MPa). Biocompatibility and lack of toxic effect give both composites a perspective for osteoplastic application, but composites doped with ZnONPs are more attractive.

Histopathological evaluation of the effect of melatonin gel on bone regeneration in rat model

Background

The purpose of this research was to investigate the effects of different doses of topical melatonin gel on bone regeneration in rat calvarial defects using histological analysis.

Materials and Methods

Fifteen adult female Wistar rats weighing approximately 200 g were used and 8 mm in diameter defects were created in their calvaria. The rats were divided into three groups: 1.2% melatonin gel, 5% melatonin gel, and the control group. The animals were sacrificed after 4 weeks. Hematoxylin and eosin staining were used to prepare histological sections. Statistical analysis was performed using the Analysis of variance and Tukey's post-hoc test. P < 0.05 was considered significant.

Results

The results showed a significant difference in rate of ossification (P < 0.001), area of new capillaries (P = 0.002), and mean degree of inflammation (P < 0.001) between the three groups. Comparing groups pairwise, degree of inflammation (P = 0.003) and area of new capillaries (P = 0.019) were significantly lower in the 5% melatonin gel group than the 1.2% melatonin gel group (P = 0.003). The percentage of ossification was substantially greater in the 5% melatonin gel group than in the control and 1.2% melatonin gel groups (P < 0.001).

Conclusion

Within the limitations of this animal study, our findings revealed that melatonin gel can be used as a stimulant of bone formation. Outcomes in this study show increased percentage of ossification in the melatonin groups when compared with the control, in a dose-dependent manner, as 5% melatonin gel has a greater effect on ossification.

Does Melatonin Associated with Nanostructured Calcium Phosphate Improve Alveolar Bone Repair?

Background and objectives: Calcium phosphates have been widely used as bone substitutes, but their properties are limited to osteoconduction. The association of calcium phosphates with osteoinductive bioactive molecules has been used as a strategy in regenerative medicine. Melatonin has been studied due to its cell protection and antioxidant functions, reducing osteoclastic activity and stimulating newly formed bone. This study aimed to evaluate the effect of topical application of melatonin associated with nanostructured carbonated hydroxyapatite microspheres in the alveolar bone repair of Wistar rats through histological and histomorphometric analysis. Materials and Methods: Thirty female Wistar rats (300 g) were used, divided randomly into three experimental groups (n = 10), G1: nanostructured carbonated hydroxyapatite microspheres associated with melatonin gel (CHA-M); G2: nanostructured carbonated hydroxyapatite (CHA); G3: blood clot (without alveolar filling). The animals were euthanized after 7 and 42 days of the postoperative period and processed for histological and histomorphometric evaluation. Kruskal-Wallis and Dunn's post-test were applied to investigate statistical differences between the groups at the same time point for new bone and connective tissue variables. Mann-Whitney was used to assess statistical differences between different time points and in the biomaterial variable. Results: Results showed a greater volume of residual biomaterial in the CHA-M than the CHA group (p = 0.007), and there were no significant differences in terms of newly formed bone and connective tissue between CHA and CHA-M after 42 days. Conclusions: This study concluded that both biomaterials improved alveolar bone repair from 7 to 42 days after surgery, and the association of CHA with melatonin gel reduced the biomaterial's biodegradation at the implanted site but did not improve the alveolar bone repair.

Hormone and implant osseointegration: Elaboration of the relationship among function, preclinical, and clinical practice

As clusters of peptides or steroids capable of high-efficiency information transmission, hormones have been substantiated to coordinate metabolism, growth, development, and other physiological processes, especially in bone physiology and repair metabolism. In recent years, the application of hormones for implant osseointegration has become a research hotspot. Herein, we provide a comprehensive overview of the relevant reports on endogenous hormones and their corresponding supplementary preparations to explore the association between hormones and the prognosis of implants. We also discuss the effects and mechanisms of insulin, parathyroid hormone, melatonin, vitamin D, and growth hormone on osseointegration at the molecular and body levels to provide a foothold and guide future research on the systemic conditions that affect the implantation process and expand the relative contraindications of the implant, and the pre-and post-operative precautions. This review shows that systemic hormones can regulate the osseointegration of oral implants through endogenous or exogenous drug-delivery methods.

Effects of Drugs and Chemotherapeutic Agents on Dental Implant Osseointegration: Narrative Review

BACKGROUND

Dental implants have been one of the most popular treatments for rehabilitating individuals with single missing teeth or fully edentulous jaws since their introduction. As more implant patients are well-aged and take several medications due to various systemic conditions, clinicians should be mindful of possible drug implications on bone remodeling and osseointegration.

OBJECTIVE

The present study aims to study and review some desirable and some unwelcomed implications of medicine on osseointegration.

METHODS

A broad search for proper relevant studies were conducted in four databases, including Web of Science, Pubmed, Scopus, and Google Scholar.

RESULTS

Some commonly prescribed medicines such as nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, proton pump inhibitors (PPIs), selective serotonin reuptake inhibitors (SSRIs), anticoagulants, metformin, and chemotherapeutic agents may jeopardize osseointegration. On the contrary, some therapeutic agents such as anabolic, anti-catabolic, or dual anabolic and anti-catabolic agents may enhance osseointegration and increase the treatment's success rate.

CONCLUSION

Systemic medications that enhance osseointegration include mineralization promoters and bone resorption inhibitors. On the other hand, medications often given to the elderly with systemic problems might interfere with osseointegration, leading to implant failure. However, to validate the provided research, more human studies with a higher level of evidence are required.

Experimental Study on the Influence of Apigenin K and Melatonin in Socket Preservation as Bone Stimulators: An Experimental Study in Beagle Dogs

The aim is to evaluate whether apigenin K and melatonin M5250 were able to stimulate bone formation after tooth extraction at one, two, and three months follow-up. Six male beagle dogs were used. Apigenin K and melatonin M5250 immersed in hemostatic collagen sponges were placed in the third and fourth premolar and the first molar extracted sockets; the second premolar was used as control. At one, two, and three months, bone core biopsies were performed, and picrosirius–hematoxylin was used for the staining process. In the first month, a higher amount of calcified bone tissue was observed in the melatonin (77.87% ± 1.2%) and apigenin K (69.81% ± 1.8%) groups than the control group (57.27% ± 0.54%), with apparent discrepancies in values between the three groups (p < 0.04). In the second month, there was a considerable improvement in the results in the areas with melatonin (79.81% ± 0.11%) than in those of apigenin K (71.65% ± 0.52%) and control (64.77% ± 0.44%) (p < 0.04). In the third month, the number of mature bone was similar to all the groups. The creation of new bone was significant in the melatonin group (82.78% ± 0.87%), followed by the apigenin K group (78.76% ± 0.43%) and the control group (57.27% ± 0.11%). From this experimental study in dogs, it can be concluded that melatonin and apigenin K can accelerate the process of mineralization of the bone matrix, and thus the creation of laminae in the early stages of healing (1 month). Less reabsorption of the post-extraction sockets can be expected with the topical application of melatonin and apigenin K. It seems that the stimulatory effects of bone healing induced by the topical application of melatonin and apigenin K are defect-size-dependent, being more evident in small defects compared to larger defects.

Daily melatonin administration improves osseointegration in pinealectomized rats

The hypothesis of this study was that the peri-implant bone healing of the group of pinealectomized rats would differ from the control group. The samples were subjected to immunohistochemical, microtomographic (total porosity and connectivity density), and fluorochrome (mineralized surface) analyses.