Injectable bone substitute to preserve alveolar ridge resorption after tooth extraction: a study in dog

Evaluation of the osteoconductive properties of scaffold containing platete-enriched-fibrin (PRF) with three calcium phosphate (TCP) in the alveolar socket repair after tooth extraction: An animal study

Bone regeneration can be accomplished through osteogenesis, osteoinduction, and osteoconduction mechanisms. This study aimed to investigate the properties of the PRF scaffold with tricalcium phosphate nanoparticles in socket preservation in an animal model. Fabrication of PRF performed. In this experimental study, 18 rats were divided into three negative control, PRF, and PRF/TCP groups. The mechanical and chemical tests including swelling rate, degradation time, and MTT tests were applied to the scaffolds. In each animal, the first maxillary right molar was extracted, and extraction sites of test groups were filled with a resorbable biocompatible biomaterial in situ hardening bone substitute. After 2 and 4 weeks all animals were sacrificed and examined histopathologically and with qRT-PCR. Histological results showed TCP in combination with PRF accelerates bone regeneration with the highest amount of lamellar bone and collagen formation compared to the control and PRF alone. Mechanical and chemical tests on the scaffolds showed the addition of TCP to the PRF scaffold decreases the swelling rate and increases the degradation time. qRT-PCR showed expression of osteogenic genes increased significantly (p < 0.05) in PRF/TCP and PRF, respectively. In conclusion, the gelatin hydrogel containing PRF/TCP scaffold led to more bone formation after tooth extraction. Therefore, the injectable PRF\TCP hydrogel is a promising candidate for bone repair and regeneration.

Extraction socket preservation

Extraction socket preservation (ESP) is widely performed after tooth extraction for future implant placement. For successful outcome of implants after extractions, clinicians should be acquainted with the principles and indications of ESP. It is recommended that ESP be actively implemented in cases of esthetic areas, severe bone defects, and delayed implant placement. Dental implant placement is recommended at least 4 months after ESP.

The Potential of Natural Propolis Extract Combined with Bovine Bone Graft in Increasing Heat Shock Protein 70 and Osteocalcin on Socket Preservation

OBJECTIVE

 This study aims to combine natural propolis with bovine bone graft (BBG) as a means of extraction socket preservation after 3 and 7 days toward expression of heat shock protein (HSP) 70 and osteocalcin to regenerate bone.

MATERIALS AND METHODS

 The Cavia cobaya were divided into eight groups, each consisting of seven samples. Their lower left incisors were extracted and induced with PEG, propolis extract, BBG, and a combination of propolis extract BBG. The research subjects were terminated on days 3 and 7 postextraction. Immunohistochemical and histopathological examinations were subsequently performed to observe HSP 70 expression, osteocalcin expression, osteoblasts, and osteoclasts.

STATISTICAL ANALYSIS

 Data obtained were then analyzed with one-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) tests.

RESULTS

 Both the groups with the combination of propolis extract and BBG on days 3 and 7 were found to present the highest number of HSP70 expression, osteocalcin expression, and osteoblast cells as well as the lowest number of osteoclasts.

CONCLUSION

 Both the groups with the combination of propolis extract and BBG on days 3 and 7 were found to present the highest number of HSP70 expression, osteocalcin expression, and osteoblast cells as well as the lowest number of osteoclasts.

Effects of mangosteen peel extract combined with demineralized freeze-dried bovine bone xenograft on osteocalcin, collagen 1, and osteoblast as alveolar bone regeneration in socket preservation

Background:

Tooth extraction will provoke changes in alveolar bone morphology and dimensions. Postextraction bone resorption can lead to significant problems for restorative dentistry. Therefore, the extracted tooth socket needs to be preserved to reduce alveolar ridge bone resorption. This research aimed to analyze the expression and levels of osteocalcin, collagen 1, and osteoblasts in extracted tooth sockets filled with a combination of mangosteen peel extract and demineralized freeze-dried bovine bone xenograft (DFDBBX).

Material and Methods:

Fifty-six Cavia cobaya, whose lower left incisors had been extracted, were divided into eight groups according to the substance used to fill their sockets on days 7 and 30, Poly ethylene glycol, DFDBBX, mangosteen peel extract, or a combination of mangosteen peel extract and DFDBBX. This research was conducted in several stages; the application of mangosteen peel extract combined with graft material was performed as the form of tooth extraction socket preservation. The C. cobaya rats were subsequently examined by immunohistochemical methods to measure osteocalcin and collagen 1 expressions, whereas histological examination was conducted to calculate the number of osteoblasts in accordance with the duration of the research.

Results:

On days 7 and 30, the group treated with a combination of DFDBBX and mangosteen peel extract which had the highest expression and levels of osteocalcin, collagen 1, and osteoblasts.

Conclusion:

The administration of mangosteen peel extract combined with DFDBBX as a means of tooth extraction socket preservation can increase osteocalcin and collagen 1 expression. Consequently, osteoblasts as a means of alveolar bone regeneration will increase in number.

The potential of mangosteen (Garcinia mangostana) peel extract, combined with demineralized freeze-dried bovine bone xenograft, to reduce ridge resorption and alveolar bone regeneration in preserving the tooth extraction socket

BACKGROUND

Following the extraction of a tooth, bone resorption can cause significant problems for a subsequent denture implant and restorative dentistry. Thus, the tooth extraction socket needs to be maintained to reduce the chance of any alveolar ridge bone resorption.

OBJECTIVE

The objective of this study is to determine whether the administration of mangosteen peel extracts (MPEs), combined with demineralized freeze-dried bovine bone xenograft (DFBBX) materials for tooth extraction socket preservation, could potentially reduce inflammation by decreased the expression of nuclear factor κβ (NfKb) and receptor activator of nuclear factor-κβ ligand (RANKL), to inhibit alveolar bone resorption, and increased of bone morphogenetic protein-2 (BMP2) expressions to accelerate alveolar bone regeneration.

MATERIALS AND METHODS

This study consists of several stages. First, a dosage of MPE combined with graft materials was applied to a preserved tooth extraction socket of a Cavia cobaya. Second, the C. cobaya was examined using immune histochemical expression of NfKb, RANKL, BMP2, as well as histology of osteoblasts and osteoclasts. The research was statistically analyzed, using an analysis of variance test and Tukey honest significant difference test.

RESULTS

The results of this research were that it was determined that MPEs combined with graft materials on a preserved tooth extraction socket can reduce NfKb, RANK, and osteoclasts also increase of BMP2 and osteoblast.

CONCLUSION

The induction of MPEs and DFBBX is effective in reducing inflammation, lowering osteoclasts, decreasing alveolar bone resorption, and also increasing BMP2 expression and alveolar bone regeneration.

Biphasic calcium phosphate ceramics for bone reconstruction: A review of biological response

Autologous bone graft is considered as the gold standard in bone reconstructive surgery. However, the quantity of bone available is limited and the harvesting procedure requires a second surgical site resulting in severe complications. Due to these limits, scientists and clinicians have considered alternatives to autologous bone graft. Calcium phosphates (CaPs) biomaterials including biphasic calcium phosphate (BCP) ceramics have proven efficacy in numerous clinical indications. Their specific physico-chemical properties (HA/TCP ratio, dual porosity and subsequent interconnected architecture) control (regulate/condition) the progressive resorption and the bone substitution process. By describing the most significant biological responses reported in the last 30years, we review the main events that made their clinical success. We also discuss about their exciting future applications as osteoconductive scaffold for delivering various bioactive molecules or bone cells in bone tissue engineering and regenerative medicine.

STATEMENT OF SIGNIFICANCE

Nowadays, BCPs are definitely considered as the gold standard of bone substitutes in bone reconstructive surgery. Among the numerous clinical studies in literature demonstrating the performance of BCP, Passuti et al. and Randsford et al. studies largely contributed to the emergence of the BCPs. It could be interesting to come back to the main events that made their success and could explain their large adhesion from scientists to clinicians. This paper aims to review the most significant biological responses reported in the last 30years, of these BCP-based materials. We also discuss about their exciting future applications as osteoconductive scaffold for delivering various bioactive molecules or bone cells in bone tissue engineering and regenerative medicine.

A New Rat Model for Translational Research in Bone Regeneration

The European Union (EU) directive 2010/63/EU on the protection of animals used for scientific purpose focused on reducing the number of animals and refinement of breeding. Animal studies are necessary to protect human health. Lots of animal models exist to study bone regeneration, but a reliable, well reproducible, and relatively inexpensive model with the possibility for multiple testing in the same animal is still missing. Rats may serve as good models for this due to the small animal size and good cost/benefit ratio. The present study aimed to develop a novel rat caudal vertebrae critical size defect model for bone regeneration and implant osseointegration studies The study was performed using Wistar rats with weight from 380 to 450 g. An incision was made on the dorsal side of the tail. After skin and muscles retractions, the vertebrae were exposed. Critical size defects for bone tissue engineering or implant placements for titanium body experiments were possible in each of the first four caudal vertebrae. Micro-computed tomography (CT) and histology were used to detect bone growth. There was no bone formation in the defects after 1 or 2 months of healing. When a calcium phosphate biomaterial was used (Bio-Oss^®; Geistlich Pharma AG, Wolhusen, Switzerland), a good stability of the material in the defect was noted and bone growth was visible after 1 or 2 months. Results based on implant placement showed good primary stability after 3 months of healing. MicroCT showed integrated implant position through the vertebra. These results suggest that the rat caudal vertebrae may serve as a good new model for studying bone regeneration and implant osseointegration with the possibility of multiple testing within the same experimental animal and the potential to decrease number of experimental animals.

Minimally traumatic alveolar ridge augmentation with a tunnel injectable thermo-sensitive alginate scaffold

Injectable bone substitutes and techniques have been developed for use in minimally invasive procedures for bone augmentation.

Association of vitamin D3 with alveolar bone regeneration in dogs

Designed sockets prepared on the mandibles of nine Beagle dogs were divided into three groups: Calcitriol +Alloplast, Alloplast and Empty. Five of the nine dogs received Vit.D₃ and calcium supplement (Vit.D/Ca group), while the other four dogs without supplements were assigned to Non-Vit.D/Ca group. After 4 weeks, the extent of vertical ridge resorption (VRR), bone density (density), new bone formation (NBF) and implant stability quotient (ISQ) were measured. Following systemic Vit.D/Ca administration, the Empty subgroup showed significant differences from the Calcitriol + Alloplast subgroup on variants NBF/Density/VRR and the Alloplast subgroup on items NBF/Density/ISQ/VRR. Alternatively, the Calcitriol + Alloplast subgroup revealed higher values of NBF/Density/ISQ (P < 0.001) and a lower VRR value (P = 0.001) than the Alloplast subgroup. Although there were no significant differences in NBF (P = 0.349), density (P = 0.796), ISQ (P = 0.577) and VRR (0.979) comparisons on alloplast treatment between the Vit.D/Ca and Non-Vit.D/Ca groups, local application with Calcitriol + Alloplast demonstrated better NBF/Density/ISQ (P = 0.02 to <0.001) effects than which of Alloplast subgroups. Consequently, the results showed that both systemic and local vitamin D₃ treatment might accelerate bone regeneration in dogs. Within the using dose, systemic vitamin D₃ treatment displayed a superior stimulating effect than local vitamin D₃ application did.

Ridge preservation after tooth extraction

BACKGROUND

Following tooth extraction, the alveolar ridge will undergo dimensional changes. This change may complicate the subsequent restorative procedure when oral implants are chosen. "Alveolar ridge preservation" has been assessed in various studies.

AIM

To evaluate the more recent studies on this topic and to explore new insights under this topic.

MATERIAL AND METHODS

Animal studies and clinical studies have addressed different techniques.

RESULTS AND CONCLUSIONS

Implants placed into the fresh extraction sockets do not prevent the resorption of the alveolar bone. Simultaneous guided bone regeneration could partially resolve alveolar bone resorption. The use of root-formed implants does not preserve alveolar ridges. Moreover, various bone substitutes have been tested: magnesium-enriched hydroxyapatite, human demineralized bone matrix, and deproteinized bovine bone mineral have been shown to be effective in ridge preservation. Applying the guided bone regeneration principle using bone substitutes together with a collagen membrane has shown clear effects on preserving alveolar ridge height as well as ridge width. Soft tissue grafts or primary closure did not show beneficial effect on preserving the alveolar bone.

The association of hydrogel and biphasic calcium phosphate in the treatment of dehiscence-type peri-implant defects: an experimental study in dogs

Hydrogel polymers have many applications in regenerative medicine. The aim of this study in dogs was to investigate bone regeneration in dehiscence-type peri-implant defects created surgically and treated with (i) biphasic calcium phosphate (BCP) granules alone; (ii) a composite putty hydroxypropyl methylcellulose (HPMC)/BCP (MBCP/putty); and (iii) a polymer crosslinked membrane of silanized-HPMC (Si-HPMC/BCP) compared with empty controls. At 3 months, new bone formation was significantly more important in defects filled with HPMC/BCP or Si-HPMC/BCP compared with spontaneous healing in control (P = 0.032 and P = 0.046 respectively) and more substantial compared with BCP alone. Furthermore, new bone formation in direct contact with the implant surface was observed in all three groups treated with BCP. The addition of HPMC to the BCP granules may have enhanced the initial stability of the material within the blood clot in these large and complex osseous defects. The Si-HPMC hydrogel may also act as an occlusive membrane covering the BCP, which could improve the stability of the granules in the defect area. However, the crosslinking time of the Si-HPMC is too long for easy handling and the mechanical properties remain to be improved. The composite MBCP/putty appears to be a valuable bone-graft material in complex defects in periodontology and implantology. These encouraging results should now be confirmed in clinical studies.

Gelation behavior of in situ forming gels based on HPMC and biphasic calcium phosphate nanoparticles

In this study, in situ forming gels are prepared using biphasic calcium phosphate (BCP) as filler and hydroxypropyl methylcellulose (HPMC) as a matrix exhibiting temperature-sensitive behavior. BCP was composed of β-tricalcium phosphate (β-TCP) with plate-like morphology and nano-sized hyadroxyapatite (HAp). Gel permeation chromatography (GPC) and rheological results showed that low molecular weight HPMC had lower gelation temperature. Effects of BCP content and HAp/β-TCP ratio on rheological behavior of the gels were investigated. According to the results, all samples showed a pseudoplastic behavior and their viscosity increased with increasing mineral phase, especially β-tricalcium phosphate. In order to investigate interaction mechanisms between the mineral phase and polymer and also the effects of ion release, particle size, hydrophobisity, and hydrophilisity, hydrophobic and hydrophilic silica with different particle sizes were also utilized. Results showed that factors affecting the hydrophobisity and hydrophilisity of solution may influence the rheological properties.

Dimensional Ridge Preservation with a Novel Highly Porous TiO(2) Scaffold: An Experimental Study in Minipigs

Despite being considered noncritical size defects, extraction sockets often require the use of bone grafts or bone graft substitutes in order to facilitate a stable implant site with an aesthetically pleasing mucosal architecture and prosthetic reconstruction. In the present study, the effect of novel TiO(2) scaffolds on dimensional ridge preservation was evaluated following their placement into surgically modified extraction sockets in the premolar region of minipig mandibles. After six weeks of healing, the scaffolds were wellintegrated in the alveolar bone, and the convex shape of the alveolar crest was preserved. The scaffolds were found to partially preserve the dimensions of the native buccal and lingual bone walls adjacent to the defect site. A tendency towards more pronounced vertical ridge resorption, particularly in the buccal bone wall of the nongrafted alveoli, indicates that the TiO(2) scaffold may be used for suppressing the loss of bone that normally follows tooth extraction.

Treatment of periodontal defects in dogs using an injectable composite hydrogel/biphasic calcium phosphate

An injectable composite silanized hydroxypropyl methyl cellulose/biphasic calcium phosphate (Si-HPMC/BCP) has been investigated in humans with promising results. The aim of this study was to evaluate his efficacy for treating periodontal defects (canine fenestration and premolar furcation) in dog models. At 3 months, we observed that bone formation around BCP particles in furcation model is more discernible but not statistically significant in defects filled with Si-HPMC/BCP compared to healing in control. We suggest that BCP particles sustain the bone healing process by osteoconduction, while the Si-HPMC hydrogel enhances intergranular cohesion and acts as an exclusion barrier. Furthermore, bone ingrowth is not so distinctive in superficial defects where the biomaterial appears unstable. These results with Si-HPMC/BCP are encouraging. In addition, this biomaterial is easy to use and simplifies the process of filling periodontal lesions. However, more researches are needed to improve the viscosity and hardness to adjust the material to the specificities of periodontal defects.

Alveolar ridge augmentation in irradiated rabbit mandibles

Oral carcinomas are frequently treated with a nonsegmental mandibulectomy plus radiotherapy. Improving the quality of life of these patients depends on the possibilities for dental rehabilitation. The aim of this study was to increase the alveolar ridge height. Twelve white New Zealand rabbits underwent surgery to produce a 11 x 9 x 7 mm(3) horizontal bicortical full-thickness defect at the alveolar ridge of the left mandible. Six were implanted with a composite associating resorbable collagen membrane filled with micro-macroporous biphasic calcium phosphate granules. After a daily radiation delivery schedule for 4 weeks, a total autologous bone marrow graft was injected percutaneously into the center of the implant. All animals were sacrificed at 16 weeks. Successful osseous colonization was observed in all implants. Significant ridge augmentation was observed (p = 0.0349) in the implanted group compared with the control group. This study contributed to producing an experimental model for oncological mandible defects in rabbits.

Histomorphometric assessment of bone formation in sinus augmentation utilizing a combination of autogenous and hydroxyapatite/biphasic tricalcium phosphate graft materials: at 6 and 9 months in humans

OBJECTIVE

The aim of this study was to examine the efficacy of a new biphasic hydroxyapatite/tricalcium phosphate (HA/TCP) bone substitute in combination with particulate autogenous bone in sinus floor augmentation procedures.

MATERIAL AND METHODS

A simultaneous or a two-stage sinus augmentation and implant placement were conducted in 28 patients. A mixture of HA/TCP and autogenous bone chips in a 1 : 1 ratio was used as the grafting biomaterial. Cylindrical specimen bone retrieval was performed in all patients except one. Specimens were harvested either at 6 (n=14) or 9 (n=13) months post-augmentation. For histologic and histomorphometric evaluations, the non-decalcified tissue processing (Donath's technique) was performed.

RESULTS

Newly formed bone around the grafted particles was found in all samples. The encircling, highly cellular bone followed the outline of the grafted particles in direct contact. Both woven and lamellar types of bone were observed. Morphometrically, the total mean bone area fraction of all sections was 34.8+/-10.3%, increasing from 28.6+/-7.8% at 6 months to 41.6+/-8.3% at 9 months (P<0.001). Mean particle area fraction average was 25.5+/-11.6% and 23.5+/-9.3% at 6 and 9 months, respectively, with a total mean of 24.5+/-10.4%. The increase in bone area fraction was not significantly correlated to the decrease of the grafted particles area fraction.

CONCLUSIONS

The biphasic HA/TCP showed biocompatible and osteoconductive properties. This alloplast as a composite with autogenous bone chips promotes newly formed bone, which increases in its fraction along an extended healing period.

Multiphasic Biomaterials: A Concept for Bone Substitutes Developed in the "Pays de la Loire"

This paper reports on the research into multiphase bone substitutes carried out by laboratories from the ‘Pays de la Loire’ region in France. This collaborative research was funded by both the French Government and the Regional Council in the period 2000-2007. Calcium phosphate bioceramics, polymers and combinations have been developed as bone substitutes for various maxillofacial and orthopaedic applications. These bone substitutes should support and regenerate bone tissue and resorb after implantation. In the bone tissue engineering area, they have been combined with autologous bone marrow cells or bioactive factors. The bone substitutes were tested in various animal models mimicking clinical situations or under pathological conditions (osteoporosis). In order to complete our research, the multiphase materials were also evaluated in clinical trials.