Evaluation of dental socket healing after using of porous titanium granules: Histologic and histomorphometric assessment in dogs

Porous Titanium Granules in comparison with Autogenous Bone Graft in Femoral Osseous Defects: A Histomorphometric Study of Bone Regeneration and Osseointegration in Rabbits

Background

The high resorption rate of autogenous bone is a well-documented phenomenon that can lead to insufficient bone quality and quantity in an augmented area. Nonresorbable bone substitutes might perform better than autogenous bone in certain applications if they are able to provide adequate bone formation and graft osseointegration.

Purpose

The aim of this study was to compare the osseous regeneration and graft integration in standardized defects in the rabbit femur treated either with porous titanium granules or autogenous osseous graft.

Materials and Methods

Standardized femoral osseous defects were surgically induced in 45 New Zealand rabbits. Fifteen were treated with porous titanium granules (TIGRAN™-PTG) and membrane (PTGM), 15 with autogenous graft and membrane (AGM), and 15 with membrane alone (CM, control). At six weeks, the defects were assessed histologically and histomorphometrically.

Results

PTGM as compared to AGM presented similar percentages of newly formed bone tissue, but a significantly higher fraction of the region of interest was filled with the bone substitute material. Accordingly, the composite of new bone plus bone substitute material showed significantly higher volumes for PTGM. Yet, the smaller amount of remaining autogenous bone was far better osseointegrated than the titanium granules, which in large regions showed no connection to newly formed bone. Both PTGM and AGM as compared to CM presented higher values of newly formed bone.

Conclusions

This study demonstrated that PTG was similarly effective as autogenous osseous graft in achieving osseous regeneration while PTG performed markedly better in graft volume stability. The resulting higher total percentage of new bone combined with the bone substitute material in PTG could provide a superior foundation for implant placement.

Osteogenic Potential of Porous Titanium. An Experimental Study in Sheep

The search for osteoinductive as well as osteoconductive materials has led to the novel idea of using titanium in bone augmentations of the alveolar crest. Due to its excellent biocompatibility and favorable osteogenic properties, highly porous TiO₂ granules has been proposed as a promising material for non-resorbable synthetic bone grafts in the restoration of large bone defects, and for bone augmentation in dental applications.

OBJECTIVES

The aim of this study was to investigate the osteoconductive properties and biological performance of porous titanium granules used in osseous defects adjacent to the maxillary sinus in sheep. The experimental animal study involved 15 yearling sheep with a focus on the osteogenic potential of porous titanium used for subantral augmentation.

MATERIAL AND METHODS

Calibrated defects were prepared in the subantral region of sheep. The defects were randomized into tests and control group. The test defects were grafted with porous titanium granules (PTG), whereas control defects were left empty (sham). Defects were left for healing for 30, 60, and 90 days. After healing, the grafted areas were removed and finally osteoconductivity was analyzed by an orthopantograph (OPG} and histology.

RESULTS

Significantly more new bone formed in PTG grafted defects compared with sham. The control group showed significantly less expression of key inflammation cells, but with no significant difference in key inflammation cells compared with the experimental groups.

CONCLUSION

Porous titanium can offer as an effective alternative to calcium phosphate and bone collagen-based materials used for subantral augmentation of the maxillary bone in cases of dental implantation.

Vertical bone augmentation with titanium granule blocks in rabbit calvaria

To determine whether it is possible to vertically augment bone utilizing a block graft from compressed titanium granules mainly used previously for contained bone defects and to determine whether there exists a difference in osteoconductive properties between the white and the grey granules. In 11 rabbits, 4 titanium blocks were inserted on each rabbit's skull bone according to a randomized scheme. These blocks were made from standardized compressed titanium granules. Type A: PTG grey, small granules (Pourus Titanium Granules, Tigran, Malmö, Sweden); Type B: PTG grey, large granules; Type C: PTG white, small granules; Type D: PTG white large granules. After 12 weeks, the animals were sacrificed and specimens were collected for histology and μCT scanning. From both the μCT and histology, it can be said that bone formation was successfully achieved for all groups, and the granules maintained their volume. The histomorphometric BA (bone area) evaluation in the entire grafted area presented that there were no statistical differences between all groups tested. The lowest 1/4 BA in contact with the rabbit skull presented that groups A and C presented the highest mean BA, and group A presented significantly higher BA than that of group D (p = 0,049). No significant differences were noted between groups A, B and C. Within the limitation of this study, no differences were noted between small white or grey PTG blocks. The large granules presented less bone ingrowth area compared to the small granules and this trend was regardless of the different PTG types. The entire grafted area was not filled with new bone suggesting that bone migration occurred mostly from the existing cortical bone side suggesting contact osteogenesis.

Biomedical applications of natural-based polymers combined with bioactive glass nanoparticles

The combination of natural polymers with nanoparticles allowed the development of functional bioinspired constructs. This review discusses the composition, design, and applications of bioinspired nanocomposite constructs based on bioactive glass nanoparticles (BGNPs).

Temporal analysis of dissolution by-products and genotoxic potential of spherical zinc-silicate bioglass: "imageable beads" for transarterial embolization

Embolization of vascular tumors is an important tool in minimally invasive surgical intervention. Radiopaque, non-degradable, and non-deformable spherical zinc-silicate glass particles were produced in a range of 45-500 μm. Three size ranges (45-150, 150-300, and 300-500 μm) were used in the current study. The glass microspheres were eluted in polar (saline solution) and non-polar (dimethyl sulfoxide) medium, and ion release profiles were recorded using inductively coupled plasma atomic emission spectroscopy. Approximately 80% of Gaussian distribution was achieved by simple sieving. The ions released from the microspheres were dependent upon surface area to volume ratio as well as the nature of elution media. Greater ions were released from smaller particles (45-150 μm) having largest surface area in polar medium. For the genotoxicity bacterial mutation Ames assay, the concentrations of all the ions were well below their therapeutic concentration reported in the literature. No mutagenic effect was observed in the bacterial mutation Ames test. Hence, it can be concluded that the glass microspheres produced herein are non-mutagenic further supporting the materials potential as a suitable embolic agent.

Porous titanium granules in critical size defects of rabbit tibia with or without membranes

Recently, porous titanium granules (PTGs) have been indicated for the preservation of the dimensions of post-extraction sockets, as a filler in sinus lift procedures and for the treatment of peri-implant and periodontal defects, based on the osteoconductivity and dimensional stability of the titanium granules. However, there is a lack of information regarding the use of this material in larger defects and in conjunction with membranes. The objective of this study is to test the behavior of PTGs used to fill critical size defects in rabbit tibiae, with and without membranes. Critical defects were created in both tibiae of rabbits, divided randomly into three groups: Group A (defect filled with PTG), Group B (defect filled with PTG+collagen membrane) and a control group (empty defect). After six weeks, histomorphometric analysis was performed. The results showed more defect closures at the cortical area (87.37%±2.2%) and more bone formation at the marrow area (57.6%±1.3%) in Group B, in comparison with the other groups (P<0.05); the use of membranes improved the material stability expressed as more percentages of the original material when membranes were used (P<0.05). Finally, inflammatory reactions were observed when the granules were not protected by membranes. In spite of the limitations of this animal study, it may be concluded that PTG particles are osteoconductive and allow bone growth. The PTG particles must be covered by a membrane, especially when grafting larger defects, in order to control particle migration, promote clot stabilization and separate the PTG graft from undesired soft tissue cells.