A Novel HA/β-TCP-Collagen Composite Enhanced New Bone Formation for Dental Extraction Socket Preservation in Beagle Dogs

Biomaterials and therapeutic strategies designed for tooth extraction socket healing

Tooth extraction is the most commonly performed oral surgical procedure, with a wide range of clinical indications. The oral cavity is a complex microenvironment, influenced by oral movements, salivary flow, and bacterial biofilms. These factors can contribute to delayed socket healing and the onset of post-extraction complications, which can burden patients' esthetic and functional rehabilitation. Achieving effective extraction socket healing requires a multidisciplinary approach. Recent advancements in materials science and bioengineering have paved the way for developing novel strategies. This review outlines the fundamental healing processes and cellular-molecular interactions involved in the healing of extraction sockets. It then delves into the current landscape of biomaterials for socket healing, highlighting emerging strategies and potential targets that could transform the treatment paradigm. Building upon this foundation, this review also presents future directions and identifies challenges associated with the clinical application of biomaterials for extraction socket healing.

Mimicking osteoid 3D porous dense microfiber silk fibroin embedded poly(vinyl alcohol) scaffold for alveolar ridge preservation

Alveolar ridge loss presents difficulties for implant placement and stability. To address this, alveolar ridge preservation (ARP) is required to maintain bone and avoid the need for ridge augmentation using socket grafting. In this study, a scaffold for ARP was created by fabricating a 3D porous dense microfiber silk fibroin (mSF) embedded in poly(vinyl alcohol) (PVA), which mimics the osteoid template. The research utilized a freeze-thawing technique to create a mimicked osteoid 3D porous scaffold by incorporating different amounts of mSF into the PVA, namely, 1%, 3%, 5% and 7%. Subsequently, a 3D profilometer machine and a scanning electron microscope were employed to examine the morphology and size of the mSF and the mimicked osteoid 3D porous scaffold in all groups. Thermal characteristics and crystalline structure were analyzed before assessing the water contact angle, swelling behavior, degradation and mechanical properties. The experiment evaluated the biological performance of the mimicked osteoid 3D porous scaffold by examining the efficacy of osteoblast cell adhesion, proliferation, viability, protein synthesis, alkaline phosphatase (ALP) activity and calcium synthesis. Finally, the ability of osteoblast cells to regulate the osteoid matrix deposition on the osteoid 3D porous scaffold was assessed by mimicking the dynamic bone environment using rat mesenchymal stem cells. The findings suggest that incorporating mSF into PVA enhances the interconnective pore size, crystalline structure and thermal behavior of the mimicked osteoid 3D porous scaffold. The hydrophilicity of PVA decreased with an increase in the proportion of mSF, while a higher proportion of mSF resulted in increased swelling and mechanical characteristics. Incorporating a greater proportion of mSF, specifically 5% and 7%, led to a reduced rate of degradation. The addition of 5% mSF to the PVA 3D porous scaffold resulted in remarkable biological properties and excellent osteoconductive activity.

Induction of osteogenic differentiation by the extracellular matrix of fetal bone tissues and adult cartilage

Decellularized cortical bone powder derived from adult animals has been shown to induce bone remodeling. Furthermore, it is increasingly evident that the extracellular matrix (ECM) within decellularized tissues differs depending on the source tissue and the age of the animal, leading to distinct effects on cells. In this study, we prepared powders from decellularized fetal and adult porcine bone tissues and conducted biological analyses to determine if the decellularized tissue could induce adipose-derived stem cell differentiation. Decellularized fetal tissues and adult cortical bone were converted into powder by cryomilling, but decellularized adult bone marrow and cartilage were not powdered through this process. In vitro assessments revealed that decellularized fetal tissues, decellularized adult cartilage extract, and decellularized fetal cartilage powder can induce osteoblast differentiation. This study suggests that decellularized fetal bone tissues and adult cartilage contain ECM components that can induce osteoblast differentiation. Additionally, it highlights the utility of decellularized fetal cartilage powder for bone reconstruction.

Performance of a multiphase bioactive socket plug with a barrier function for alveolar ridge preservation

The natural healing process of extraction socket and traditional socket plug material could not prevent buccal bone wall resorption and down growth of epithelium from the socket orifice. A multiphase bioactive socket plug (BP) is designed to overcome the natural healing process by maintaining the three-dimensional (3D) volume of extraction sockets, particularly in sockets with wall defects, and later provide sufficient alveolar bone volume for implant placement. The study aimed to fabricate and evaluate the physical, chemical, and biological performance of BPin vitro. The BP was fabricated through freeze-drying and layer-by-layer assembly, comprised of a base serving as a scaffold, a central portion for promoting bone regeneration, an upper buccal portion for maintaining alveolar socket dimension with a covering collagen membrane (Memb) on the top and upper buccal surface to prevent soft tissue infiltration. The BP as the experimental group and a pure collagen plug (CP) as the control group were investigated and compared. Radiograph, scanning electron microscopy, and energy-dispersive spectroscopy mapping confirmed that the four-part BP was successfully assembled and fabricated. Swelling rate analysis indicated that BP, CP, and Memb reached swelling equilibrium within 1 hour. BP exhibited a high remaining weight percentage in collagenase solution (68.81 ± 2.21% on day 90) and sustained calcium ion release, reaching the maximum 0.13 ± 0.04 mmol l-1on day 14. In biological assays, BP exhibited excellent cell proliferation (The OD value increased from 0.02 on day 1 to 0.23 on day 21.). The BP group exhibited higher alkaline phosphatase activity and osteocalcin content than the CP group within 21 days. Memb and BP exhibited outstanding barrier function, as evidenced by Hematoxylin and eosin staining. In summary, the multiphase bioactive socket plug represents a promising scaffold for alveolar ridge preservation application.

Collagen-Based Biomaterials for Tissue Engineering

Collagen is commonly used as a regenerative biomaterial due to its excellent biocompatibility and wide distribution in tissues. Different kinds of hybridization or cross-links are favored to offer improvements to satisfy various needs of biomedical applications. Previous reviews have been made to introduce the sources and structures of collagen. In addition, biological and mechanical properties of collagen-based biomaterials, their modification and application forms, and their interactions with host tissues are pinpointed. However, there is still no review about collagen-based biomaterials for tissue engineering. Therefore, we aim to summarize and discuss the progress of collagen-based materials for tissue regeneration applications in this review. We focus on the utilization of collagen-based biomaterials for bones, cartilages, skin, dental, neuron, cornea, and urological applications and hope these experiences and outcomes can provide inspiration and practical techniques for the future development of collagen-based biomaterials in related application fields. Moreover, future improving directions and challenges for collagen-based biomaterials are proposed as well.

Synthetic materials in craniofacial regenerative medicine: A comprehensive overview

The state-of-the-art approach to regenerating different tissues and organs is tissue engineering which includes the three parts of stem cells (SCs), scaffolds, and growth factors. Cellular behaviors such as propagation, differentiation, and assembling the extracellular matrix (ECM) are influenced by the cell's microenvironment. Imitating the cell's natural environment, such as scaffolds, is vital to create appropriate tissue. Craniofacial tissue engineering refers to regenerating tissues found in the brain and the face parts such as bone, muscle, and artery. More biocompatible and biodegradable scaffolds are more commensurate with tissue remodeling and more appropriate for cell culture, signaling, and adhesion. Synthetic materials play significant roles and have become more prevalent in medical applications. They have also been used in different forms for producing a microenvironment as ECM for cells. Synthetic scaffolds may be comprised of polymers, bioceramics, or hybrids of natural/synthetic materials. Synthetic scaffolds have produced ECM-like materials that can properly mimic and regulate the tissue microenvironment's physical, mechanical, chemical, and biological properties, manage adherence of biomolecules and adjust the material's degradability. The present review article is focused on synthetic materials used in craniofacial tissue engineering in recent decades.

Effectiveness of a Nanohydroxyapatite-Based Hydrogel on Alveolar Bone Regeneration in Post-Extraction Sockets of Dogs with Naturally Occurring Periodontitis

Pathological mandibular fracture after dental extraction usually occurs in dogs with moderate to severe periodontitis. A nanohydroxyapatite-based hydrogel (HAP hydrogel) was developed to diminish the limitations of hydroxyapatite for post-extraction socket preservation (PSP). However, the effect of the HAP hydrogel in dogs has still not been widely investigated. Moreover, there are few studies on PSP in dogs suffering from clinical periodontitis. The purpose of this study was to evaluate the effectiveness of the HAP hydrogel for PSP in dogs with periodontitis. In five dogs with periodontitis, the first molar (309 and 409) of each hemimandible was extracted. Consequently, all the ten sockets were filled with HAP-hydrogel. Intraoral radiography was performed on the day of operation and 2, 4, 8 and 12 weeks post operation. The Kruskal-Wallis test and paired t-test were adopted for alveolar bone regeneration analysis. The results demonstrated that the radiographic grading, bone height measurement, and bone regeneration analysis were positively significant at all follow-up times compared to the day of operation. Moreover, the scanning electron microscopy with energy-dispersive X-ray spectroscopy imaging after immersion showed a homogeneous distribution of apatite formation on the hydrogel surface. Our investigation suggested that the HAP hydrogel effectively enhances socket regeneration in dogs with periodontitis and can be applied as a bone substitute for PSP in veterinary dentistry.

The Impact of Bioceramic Scaffolds on Bone Regeneration in Preclinical In Vivo Studies: A Systematic Review

Bioceramic scaffolds are appealing for alveolar bone regeneration, because they are emerging as promising alternatives to autogenous and heterogenous bone grafts. The aim of this systematic review is to answer to the focal question: in critical-sized bone defects in experimental animal models, does the use of a bioceramic scaffolds improve new bone formation, compared with leaving the empty defect without grafting materials or using autogenous bone or deproteinized bovine-derived bone substitutes? Electronic databases were searched using specific search terms. A hand search was also undertaken. Only randomized and controlled studies in the English language, published in peer-reviewed journals between 2013 and 2018, using critical-sized bone defect models in non-medically compromised animals, were considered. Risk of bias assessment was performed using the SYRCLE tool. A meta-analysis was planned to synthesize the evidence, if possible. Thirteen studies reporting on small animal models (six studies on rats and seven on rabbits) were included. The calvarial bone defect was the most common experimental site. The empty defect was used as the only control in all studies except one. In all studies the bioceramic materials demonstrated a trend for better outcomes compared to an empty control. Due to heterogeneity in protocols and outcomes among the included studies, no meta-analysis could be performed. Bioceramics can be considered promising grafting materials, though further evidence is needed.

Ridge Augmentation Using β-Tricalcium Phosphate and Biphasic Calcium Phosphate Sphere with Collagen Membrane in Chronic Pathologic Extraction Sockets with Dehiscence Defect: A Pilot Study in Beagle Dogs

This study was conducted to comparatively examine spontaneous healing versus ridge augmentation, in surgically-created dehiscence defects, associated with chronic pathology in dogs. Mandibular second, third and fourth premolars (P2, P3 and P4) were hemi-sectioned, and a dehiscence defect was created at the mesial root, while a groove was made on the buccal area from the top of the teeth to the bottom of the defect, exposing the dental pulp. The mesial roots of P2, P3 and P4 were extracted 1 month after the induction of the dehiscence defect with chronic pathology. Three teeth were randomly allocated to these experimental groups: (i) spontaneous healing without any bone graft (Control group: C); (ii) ridge augmentation with β-tricalcium phosphate (β-TCP) granules (Test 1 group: T1); and (iii) ridge augmentation with 60% hydroxyapatite (HA) and 40% β-TCP microspheres (Test 2 group: T2). Postmortem histopathologic examination showed significant between-group differences in C and T1 and C and T2 in bone volume/tissue volume in qualitative micro-computed tomography (CT) analysis, as well as significant intergroup differences in the coronal area at 4 and 12 weeks. The composition of connective tissue and mineralized bone in C and T1 were higher than in T2 at 4 weeks of healing, whereas the composition of mineralized bone was higher in T2 than in T1 at 12 weeks of healing. Biphasic calcium phosphate, composed of 60% HA and 40% β-TCP microsphere (i) potentially prevented marked osteoclastic resorption and (ii) promoted ridge preservation in the extraction socket with the dehiscence defect and chronic pathology.

[Application of β-TCP for bone defect restore after the mandibular third molars extraction: A splitmouth clinical trial]

OBJECTIVE

To evaluate the effect of bone defect regeneration and the periodontal status of the second molars after mandibular third molars extraction using β-tertiary calcium phosphate (β-TCP) in the test side compared with the spontaneously healed side. To the bone defect of mandibular second molars as a result of surgical removal of impacted mandibular third molars is a common phenomenon, many research shows that the mandibular second molars alveolar bone regeneration was about 1.5 mm and the periodontal pocket >7 mm was greater than 43.3% after mandibular third molars extraction. There has been significant progress researches in the repair of bone defect after the third molar removal, and bone graft filling was one of the effective methods. The bone graft substitutes include autogenous bone, allograft bone, xenograft bone and synthetic bone.

METHODS

A split mouth, randomized clinical study was designed. Fifteen patients with mandibular third molars in the same jaw planned to be extracted were enrolled in the study. One of the sockets of each patient was randomly selected and filled with easy-graftTMCLASSIC (test group). The contralateral socket was left to heal spontaneously (control group). cone beam computed tomography (CBCT) scans were performed the day after the extraction and after 6 months. The horizontal dimensional changes of the sockets were recorded. The newly formed bone volume in the bone was analyzed by CBCT, and the probing depth (PD) was recorded. Student's t test was used to evaluate the difference between the two groups for each parameter, and the P value lower than 0.05 was considered to be statistically significant.

RESULTS

Fifteen patients (30 sockets) completed the flow-up, and all the 30 sockets healed uneventfully. After 6 months' healing, the new bone volume fraction of the test group was 63.3%±2.2%, while the new bone volume fraction of the control group was 50.1%±1.9%. The vertical dimensional increment of the test group was (5.53±0.39) mm, while the vertical change of the control group was (1.53±0.27) mm. The distal buccal site PD of the second molar was (3.0±0.7) mm in the test group, and (6.5±0.8) mm in the control group. Statistically significant differences were detected between the two groups.

CONCLUSION

The randomized controlled clinical trial showed that the application of β-TCP for bone defect repair after the mandibular third molars extraction resulted in more vertical bone regeneration and less probing depth when compared with what was spontaneously healed.

[Application of β-TCP for bone defect restore after the mandibular third molars extraction: A splitmouth clinical trial]

OBJECTIVE

To evaluate the effect of bone defect regeneration and the periodontal status of the second molars after mandibular third molars extraction using β-tertiary calcium phosphate (β-TCP) in the test side compared with the spontaneously healed side. To the bone defect of mandibular second molars as a result of surgical removal of impacted mandibular third molars is a common phenomenon, many research shows that the mandibular second molars alveolar bone regeneration was about 1.5 mm and the periodontal pocket >7 mm was greater than 43.3% after mandibular third molars extraction. There has been significant progress researches in the repair of bone defect after the third molar removal, and bone graft filling was one of the effective methods. The bone graft substitutes include autogenous bone, allograft bone, xenograft bone and synthetic bone.

METHODS

A split mouth, randomized clinical study was designed. Fifteen patients with mandibular third molars in the same jaw planned to be extracted were enrolled in the study. One of the sockets of each patient was randomly selected and filled with easy-graftTMCLASSIC (test group). The contralateral socket was left to heal spontaneously (control group). cone beam computed tomography (CBCT) scans were performed the day after the extraction and after 6 months. The horizontal dimensional changes of the sockets were recorded. The newly formed bone volume in the bone was analyzed by CBCT, and the probing depth (PD) was recorded. Student's t test was used to evaluate the difference between the two groups for each parameter, and the P value lower than 0.05 was considered to be statistically significant.

RESULTS

Fifteen patients (30 sockets) completed the flow-up, and all the 30 sockets healed uneventfully. After 6 months' healing, the new bone volume fraction of the test group was 63.3%±2.2%, while the new bone volume fraction of the control group was 50.1%±1.9%. The vertical dimensional increment of the test group was (5.53±0.39) mm, while the vertical change of the control group was (1.53±0.27) mm. The distal buccal site PD of the second molar was (3.0±0.7) mm in the test group, and (6.5±0.8) mm in the control group. Statistically significant differences were detected between the two groups.

CONCLUSION

The randomized controlled clinical trial showed that the application of β-TCP for bone defect repair after the mandibular third molars extraction resulted in more vertical bone regeneration and less probing depth when compared with what was spontaneously healed.

Biphasic Calcium Phosphate Sphere Graft Combined with a Double-Layer Non-Crosslinked Collagen Membrane Technique for Ridge Preservation: A Randomized Controlled Animal Study

The purpose of this study was to compare the histologic and radiologic differences between single- and double-layer collagen membrane techniques in flapless ridge preservation. The mandibular fourth premolar and first molar of four beagle dogs were used in the experiment. Mesial roots of the teeth were extracted and root canal treatment was performed at the distal roots. Ridge preservation was performed at the extraction sites using synthetic bone graft material. A single layer (control group) or double layer (test group) of non-crosslinked collagen membrane was applied following bone graft application. Three months later, the animals were sacrificed and micro-computed tomography (micro-CT) and histomorphometric analyses were conducted. Nonparametric Mann-Whitney test was performed to compare between the control and test groups. The vertical difference between buccal and lingual crests of control and test groups was 1.28 ± 0.41 and 0.53 ± 0.37 mm, respectively (p = 0.026). The mineralized bone area in control and test groups was 31.48% ± 7.41% and 42.25% ± 9.73%, respectively (p = 0.041). Within the limit of this study, ridge preservation using the double-layer membrane technique showed a reduced buccal bone resorption and improved new-bone formation in the ridge compared to that using the single-layer membrane technique.

Prevention of Bone Resorption by HA/β-TCP + Collagen Composite after Tooth Extraction: A Case Series

After tooth extraction, alveolar ridge loss due to resorption is almost inevitable. Most of this bone loss occurs during the first six months after the extraction procedure. Many studies have indicated that applying socket-filling biomaterials after extraction can effectively reduce the resorption rate of the alveolar ridge. The purpose of this study was to investigate the clinical efficacy of the application of a hydroxyapatite/β-tricalcium plus collagen (HA/β-TCP + collagen) dental bone graft in dental sockets immediately after tooth extraction, so as to prevent socket resorption. The study was conducted on 57 extraction sockets located in the mandible and maxilla posterior regions in 51 patients. HA/β-TCP + collagen was inserted into all of the dental sockets immediately after extraction, and was covered with a flap. Follow-up was performed for three months after extraction, using radiographs and stents for the vertical and horizontal alveolar ridge measurements. A minimal alveolar bone width reduction of 1.03 ± 2.43 mm (p < 0.05) was observed. The height reduction showed a slight decrease to 0.62 ± 1.46 mm (p < 0.05). Radiographically, the bone height was maintained after three months, indicating a good HA/β-TCP + collagen graft performance in preserving alveolar bone. In conclusion, the HA/β-TCP + collagen graft demonstrated adequate safety and efficacy in dental socket preservation following tooth extraction.

Comparison of microsurgical and macrosurgical technique using bioactive synthetic bone graft and collagen membrane for an implant site development: A randomized controlled clinical trial

Background:

Implant site development can be effective in minimizing postextraction alveolar ridge resorption in the esthetic region. Microsurgical approach has demonstrated substantial improvement in soft-tissue architecture.

Aim and Objectives:

The aim of the present study was to evaluate and compare the efficacy of microsurgical technique with conventional one for implant site development utilizing biphasic hydroxyapatite/beta-tricalcium phosphate bone graft substitute and collagen membrane.

Materials and Methods:

Thirty extraction sites were planned for implant placement and randomly divided into control (macrosurgical/conventional) and test (microsurgery) sites. Clinical measurements were recorded at four different points of extraction socket, i.e., mesiobuccal, midbuccal, distobuccal, and midlingual/palatal at baseline, 3, 6, and 9 months. Postoperative neovascularization at control and test site was evaluated by ultrasound Doppler flowmetry at baseline, 10^th day, and 1 month. Radiological assessment of bone density (Hounsfield units) was measured at control and test sites at baseline, 6 and 9 months by computed tomography. Data was subjected to statistical analysis.

Results:

Significant socket fill at all the four different sites was observed and found to be statistically significant at test as compared to control group with better tissue contour after 3, 6, and 9 months. Test group demonstrated better neovascularization (P < 0.05) with significantly higher bone density (P = 0.000) at different time intervals.

Conclusions:

The results indicate that the augmentation of extraction sockets, not only improved the quality of bone in both the techniques but the utilization of microsurgical instruments and microsutures under magnification definitely enhanced the quality of soft tissues which is imperative for successful implant placement and its survival.

Antibiotic Prophylaxis on Third Molar Extraction: Systematic Review of Recent Data

The aim of this paper was to highlight the most widely antibiotic protocols applied to the dental field, especially in the surgical treatment of impacted wisdom teeth. Once these protocols were screened, all the possible advantages or disadvantages for each drug and each posology were recorded in this review. In recent years, the need to use these protocols has been debated in the literature. The data obtained by this review underlined how antibiotic protocols applied to oral surgery treatments only included surgeries performed on patients who did not present other systemic pathologies. The first literature review obtained 140 results, and then after the application of the inclusion criteria, 12 papers were selected. The results showed that the most commonly used protocol involved the use of penicillin and clavulanate, obtaining safe clinical and prophylactic results in the management of infections. This widely used protocol seems to guarantee high predictability and safety. The presented review highlights the current possibility of antibiotic resistance affecting patients due to drug misuse. Further clinical studies are required to state specific guidelines; however, oral surgeons involved in third molar surgery should evaluate the local and general health conditions of the patients before suggesting any drug measures for patients.

Effect of Hydroxyapatite Formation on Titanium Surface with Bone Morphogenetic Protein-2 Loading through Electrochemical Deposition on MG-63 Cells

Calcium phosphate ceramics used in dentistry and orthopedics are some of the most valuable biomaterials, owing to their excellent osteoconduction, osteoinduction, and osseointegration. Osteoconduction and osteoinduction are critical targets for bone regeneration, and osseointegration is essential for any dental implantations. In this study, a hydroxyapatite (HAp) hybrid coating layer with the sequential release of bone morphogenetic protein 2 (BMP-2) was deposited onto an etched titanium substrate by electrochemical deposition. The resulting release of BMP-2 from Ti⁻HAp was assessed by immersing samples in a simulated buffer fluid solution. Through coculture, human osteosarcoma cell proliferation and alkaline phosphatase activity were assessed. The characteristics and effect on cell proliferation of the hybrid coatings were investigated for their functionality through X-ray diffraction (XRD) and cell proliferation assays. Findings revealed that -0.8 V vs. Ag/AgCl (3 M KCl) exhibited the optimal HAp properties and a successfully coated HAp layer. XRD confirmed the crystallinity of the deposited HAp on the titanium surface. Ti-0.8 V Ti⁻HAp co-coating BMP sample exhibited the highest cell proliferation efficiency and was more favorable for cell growth. A successful biocompatible hybrid coating with optimized redox voltage enhanced the osseointegration process. The findings suggest that this technique could have promising clinical applications to enhance the healing times and success rates of dental implantation.

Bone regeneration using a porcine bone substitute collagen composite in vitro and in vivo

The biocharacteristics of xenogeneic grafts make them a possible substitute for autogenous bone grafts in dental bone graft procedures. This study aimed to develop a novel porcine graft with collagen capable of generating new bone in bone defects via osteoconduction over 8 weeks of healing and to compare it with a porcine graft. The porcine collagen graft was made to undergo a cell viability test (MTT) and alkaline phosphatase assay (ALP). The surgical procedure was performed in 20 male adult New Zealand white rabbits. Four calvarial critical-size defects of 6 mm in diameter were prepared in each rabbit. The upper left defect was filled with a porcine graft of 500–1000 μm, the upper right with a porcine collagen graft, the lower left with hydroxyapatite/beta-tricalcium phosphate and the lower right served as the control without any filling material. The rabbits were divided and sacrificed at 2, 4, 6 and 8 weeks after surgery. Histological and micro-CT scan results showed that the performance of the porcine collagen graft is superior for regenerating new bone. Porcine collagen graft showed cell viability and osteoblast-like cell differentiation in vitro. The results indicate that porcine collagen graft is a potential bone substitute for clinical application.