VEGF and MVD expression in sinus augmentation with autologous bone and several graft materials

Emerging factors affecting peri-implant bone metabolism

Implant dentistry has evolved to the point that standard implant osseointegration is predictable. This is attributed in part to the advancements in material sciences that have led toward improvements in implant surface technology and characteristics. Nonetheless, there remain several cases where implant therapy fails (specifically at early time points), most commonly attributed to factors affecting bone metabolism. Among these patients, smokers are known to have impaired bone metabolism and thus be subject to higher risks of early implant failure and/or late complications related to the stability of the peri-implant bone and mucosal tissues. Notably, however, emerging data have unveiled other critical factors affecting osseointegration, namely, those related to the metabolism of bone tissues. The aim of this review is to shed light on the effects of implant-related factors, like implant surface or titanium particle release; surgical-related factors, like osseodensification or implanted biomaterials; various drugs, like selective serotonin reuptake inhibitors, proton pump inhibitors, anti-hypertensives, nonsteroidal anti-inflammatory medication, and statins, and host-related factors, like smoking, diet, and metabolic syndrome on bone metabolism, and aseptic peri-implant bone loss. Despite the infectious nature of peri-implant biological complications, these factors must be surveyed for the effective prevention and management of peri-implantitis.

The current regenerative medicine approaches of craniofacial diseases: A narrative review

Craniofacial deformities (CFDs) develop following oncological resection, trauma, or congenital disorders. Trauma is one of the top five causes of death globally, with rates varying from country to country. They result in a non-healing composite tissue wound as they degenerate in soft or hard tissues. Approximately one-third of oral diseases are caused by gum disease. Due to the complexity of anatomical structures in the region and the variety of tissue-specific requirements, CFD treatments present many challenges. Many treatment methods for CFDs are available today, such as drugs, regenerative medicine (RM), surgery, and tissue engineering. Functional restoration of a tissue or an organ after trauma or other chronic diseases is the focus of this emerging field of science. The materials and methodologies used in craniofacial reconstruction have significantly improved in the last few years. A facial fracture requires bone preservation as much as possible, so tiny fragments are removed initially. It is possible to replace bone marrow stem cells with oral stem cells for CFDs due to their excellent potential for bone formation. This review article discusses regenerative approaches for different types of craniofacial diseases.

Evaluation of alveolar antral anastomosis in south Indian population using cone beam computed tomography: a prospective study

OBJECTIVES

The posterior superior alveolar artery (PSAA) and the infraorbital artery (IOA), both of which are ultimate branches of the maxillary artery, are connected by a horizontal anastomosis. PSAA anastomoses intraosseously and extraosseously with IOA. Profuse bleeding from the lateral wall while performing the direct sinus augmentation is a significant intraoperative complication.Thus the present study focused to assess the location of an alveolar antral anastomosis (AAA) in relation to the crest of the alveolar bone using cone beam computed tomography (CBCT).

METHODS

A total of 200 CBCT scans of patients who were indicated for implant surgery were chosen and assessed. Group 1 includes 100 dentate patients and Group 2 includes 100 partially edentulous patients. The location of anastomosis along the lateral wall of the maxillary sinus was evaluated in association with alveolar bone height with respect to three posterior maxillary teeth: first premolar, second premolar, and first molar.

RESULTS

The mean distance for P1, P2, and M1 was 21.94 ± 1.02 mm, 19.41 ± 0.40 mm, and 17.36 ± 0.51 mm, respectively, in the dentate group, whereas in the edentulous group, it was 20.07 ± 0.46 mm, 18.95 ± 0.32 mm, and 16.08 ± 0.16 mm. In 80% of participants, the distance of an AAA from the alveolar crest was between 16 and 23 mm, whereas in 12% of the participants the distance of an AAA from the alveolar crest was less than 16 mm.

CONCLUSION

The present study concludes that the first premolar region is safe for preparing the lateral window but for the second premolar and first molar additional care should be taken prior to surgery.

Maxillary sinus floor augmentation comparing bovine versus porcine bone xenografts mixed with autogenous bone graft. A split-mouth randomized controlled trial

Aim

To compare the effectiveness of two xenografts for maxillary sinus floor augmentation in terms of clinical, radiographical, histologic, and molecular outcomes.

Materials and methods

A split‐mouth randomized clinical trial was conducted at the University of Granada. Ten consecutive patients in need of bilateral two‐staged maxillary sinus floor augmentation were included. Each patient received both biomaterials (porcine bone mineral and anorganic bovine bone), which were randomly assigned for bilateral sinus augmentation. The maxillary autogenous bone scraped from the sinus access window was mixed with each xenograft at a 20:80 ratio. After a healing period of 6 months, bone biopsies were collected with a trephine during the implant placement in the regenerated area. Histologic, histomorphometrical, immunohistochemical, and molecular outcomes were analyzed. Clinical and radiographical data throughout the treatment phases were also evaluated.

Results

The resulting anatomic features were similar between both groups. After six months of graft consolidation, the graft resorption rates were similar between both biomaterials. The histologic, histomorphometrical, and immunohistochemical results showed no statistical differences between groups.

Conclusion

Anorganic bovine bone and porcine bone mineral combined with maxillary autogenous cortical bone show similar biologic and radiologic features in terms of biomaterial resorption, osteoconduction, and osteogenesis when used for maxillary sinus floor augmentation.

Polymeric Scaffolds for Dental, Oral, and Craniofacial Regenerative Medicine

Dental, oral, and craniofacial (DOC) regenerative medicine aims to repair or regenerate DOC tissues including teeth, dental pulp, periodontal tissues, salivary gland, temporomandibular joint (TMJ), hard (bone, cartilage), and soft (muscle, nerve, skin) tissues of the craniofacial complex. Polymeric materials have a broad range of applications in biomedical engineering and regenerative medicine functioning as tissue engineering scaffolds, carriers for cell-based therapies, and biomedical devices for delivery of drugs and biologics. The focus of this review is to discuss the properties and clinical indications of polymeric scaffold materials and extracellular matrix technologies for DOC regenerative medicine. More specifically, this review outlines the key properties, advantages and drawbacks of natural polymers including alginate, cellulose, chitosan, silk, collagen, gelatin, fibrin, laminin, decellularized extracellular matrix, and hyaluronic acid, as well as synthetic polymers including polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), poly (ethylene glycol) (PEG), and Zwitterionic polymers. This review highlights key clinical applications of polymeric scaffolding materials to repair and/or regenerate various DOC tissues. Particularly, polymeric materials used in clinical procedures are discussed including alveolar ridge preservation, vertical and horizontal ridge augmentation, maxillary sinus augmentation, TMJ reconstruction, periodontal regeneration, periodontal/peri-implant plastic surgery, regenerative endodontics. In addition, polymeric scaffolds application in whole tooth and salivary gland regeneration are discussed.

The role of cortical perforations in allogeneic block grafting for lateral augmentation in maxilla: A randomized clinical trial

BACKGROUND

The need of decortication on the recipient site remains unclear for bone regeneration. To our knowledge, there are no human clinical trials that studied the influence of decortication on cancellous allogeneic block grafting.

PURPOSE

The aim of the present study is to evaluate the influence of perforating the cortex of the recipient site on cancellous allogeneic block graft integration and revascularization in the maxilla.

MATERIAL AND METHODS

Twenty-six patients referred for lateral bone augmentation were included in this clinical trial. Patients received freeze-dried bone allograft cancellous blocks obtained from the iliac crest; cortical perforations of the recipient bed were performed in the test group while in the control group it was left intact. After a 4-month healing period another surgery was performed to place dental implants, and a bone biopsy was collected using a trephine. All samples underwent micro-CT scans, and were processed for histomorphometric and immunohistochemical analysis. Implant survival comparisons were made using a repeated measures analysis of variance (ANOVA) while all other variables were compared using the analysis of covariance (ANCOVA).

RESULTS

One hundred and nineteen implants were placed into 110 augmented sites. One hundred percent implant survival rate was reported during 24 months follow-up period. No differences were reported in bleeding on probing at 1 (5.6 vs 9%) and 2 years (13.2 vs 12.1%), probing pocket depth at 1 (3.4 ± 0.95 vs 3.6 ± 1.12 mm) and 2 years (3.8 ± 1.02 vs 4.1 ± 1.46 mm), and marginal bone loss at 1 (0.2 ± 0.52 vs 0.3 ± 0.57 mm) and 2 years (0.6 ± 0.91 vs 0.5 ± 0.87 mm). No statistically significant differences were found in the micro-CT and histomorphometric analysis in terms of newly formed bone (25.7 ± 11.2% vs 22.3 ± 9.7%), soft tissue (33.0 ± 14.7% vs 36.5 ± 15.7%), remnant allograft (39.3 ± 20.4% vs 41.2 ± 22.7%), and bone mineralization (57.2 ± 10.6% vs 53.8 ± 8.7%). Perforating the cortex of the recipient site had no significant effect on angiogenesis as shown by immunohistochemical analysis of CD34 positive blood vessels (39.21 ± 10.53/mm² vs 34.16 ± 12.67/mm² ).

CONCLUSION

Cancellous allogeneic bone block grafts are a clinically acceptable alternative for horizontal bone augmentation. Cortical perforations of the recipient site in the maxilla did not improve angiogenesis nor bone formation within the block graft.

Quantitative and qualitative assessments of intraosseous neurovascular canals in dentate and posteriorly edentulous individuals in lateral maxillary sinus wall

Objective

Knowledge and evaluation of the blood supply within the maxillary sinus before sinus augmentation are vital to avoid surgical complications. The lateral maxilla is supplied by branches of the posterior superior alveolar artery and infraorbital artery forming intraosseous anastomoses (IA) within the bony lateral antral wall. This study was undertaken to (i) measure mean diameter of IA and its distance from the alveolar ridge within dentate and posteriorly edentulous subjects and, (ii) qualitatively display the relationship of IA throughout its course within the lateral maxillary sinus in cone beam computed tomography (CBCT).

Method

Maxillary CBCT images of two-hundred-and-fifty-seven consecutive patients (163 men, 94 women, mean age 42 years) were analyzed. Samples were later divided into dentate (n = 142) and posteriorly edentulous (n = 115) jaws. Using both alveolar ridge and tooth location as reference points, the distance and diameter of IA were assessed.

Result

The IA was seen in 63.7% of all sinuses with 68.2% in dentate and 62.4% in edentulous. Mean distance and diameter of IA across the posterior tooth locations were 17.9 ± 3.0 mm and 1.4 ± 0.5 mm (dentate) and 15.1 ± 3.0 mm and 1.0 ± 0.5 mm (posteriorly edentulous), respectively. In each sample, there were no significant differences in distance-alveolar ridge and no significant correlations in diameter-tooth location. A statistically significant Pearson coefficient correlation between diameter and distance in dentate state was observed (r = −0.6).

Conclusion

This study reveals that dentate maxillary jaws present larger diameters as compared to posteriorly edentulous jaws, although the IA course remains the same. As these canal structures contain neurovascular bundles with diameters that may be large enough to cause clinically substantial complications, a thorough pre-surgical planning is therefore highly advisable.

Molecular and Cellular Aspects of Socket Healing in the Absence and Presence of Graft Materials and Autologous Platelet Concentrates: a Focused Review

OBJECTIVES

The present manuscript aims to critically detail the physiologic process of socket healing, in the absence or presence of grafting materials or platelet concentrates, addressing the associated molecular and cellular events that culminate in the restoration of the lost tissue architecture and functionality.

MATERIAL AND METHODS

An electronic search in the National Library of Medicine database MEDLINE through its online site PubMed and Web of Science from inception until May 2019 was conducted to identify articles concerning physiologic process of socket healing, in the absence or presence of grafting materials or platelet concentrates. The search was restricted to English language articles without time restriction. Additionally, a hand search was carried out in oral surgery, periodontology and dental implants related journals.

RESULTS

In total, 122 literature sources were obtained and reviewed. The detailed biological events, at the molecular and cellular level, that occur in the alveolus after tooth extraction and socket healing process modulated by grafting materials or autologous platelet concentrates were presented as two entities.

CONCLUSIONS

Tooth extraction initiates a convoluted set of orderly biological events in the alveolus, aiming wound closure and socket healing. The healing process comprises a wide range of events, regulated by the interplay of cytokines, chemokines and growth factors that determine cellular recruitment, proliferation and differentiation in the healing milieu, in a space- and time-dependent choreographic interplay. Additionally, the healing process may further be modulated by the implantation of grafting materials or autologous platelet concentrates within the tooth socket, aiming to enhance the regenerative outcome.

Biphasic hydroxyapatite and ß-tricalcium phosphate biomaterial behavior in a case series of maxillary sinus augmentation in humans

OBJECTIVES

The aim of this study was to evaluate and compare the morphometric components and the histological properties of pristine bone and bone grafted with a biphasic ß-tricalcium phosphate in humans using the maxillary sinus model. Reparative mesenchymal stem cells in the pristine bone and graft were also evaluated.

MATERIALS AND METHODS

For this prospective case series, sinus augmentation was performed using a biphasic ß-tricalcium phosphate. After 6 months of healing, a core of remnant native alveolar bone and grafted bone was collected with a trephine. Histological, histomorphometrical, and immunohistochemical techniques were performed. Radiological analysis through cone beam computerized tomography was also conducted.

RESULTS

A total of 10 patients were enrolled in this study. Radiologically, patients showed an average increase of crestal bone of 8.03 ± 1.72 mm. Morphologically, the grafted area was composed by 34.93 ± 14.68% of new mineralized tissue, 9.82 ± 11.42% of remnant biomaterial particles, and 55.23 ± 11.03% non-mineralized tissue. Histologically, we found no differences in the number of osteocytes per mm² (p = 0.674), osteoblasts (p = 0.893), and blood vessels (p = 0.894) in the grafted area compared to the pristine bone. Differences were found on the number of osteoclasts (15.57 ± 27.50 vs. 5.37 ± 16.12, p = 0.027). The number of Musashi-1 positive mesenchymal cells (239.61 ± 177.4 vs. 42.11 ± 52.82, p = 0.027) was also significantly higher in the grafted area than in the pristine bone.

CONCLUSION

Biphasic ß-tricalcium phosphate is a suitable biomaterial to be used in the formation of new bone in sinus floor elevation procedures in humans, not only from the histomorphometrical point of view, but also regarding the cellular and vascular quality of the regenerated bone.

Histopathological comparison of healing after maxillary sinus augmentation using xenograft mixed with autogenous bone versus allograft mixed with autogenous bone

OBJECTIVE

To compare the clinical and histologic outcomes of two different grafting materials (allograft and xenograft) when combined with autogenous bone and covered with a collagen membrane for sinus augmentation.

MATERIAL AND METHODS

A parallel case series of fourteen patients in need of a unilateral sinus augmentation was evaluated in this study. Seven patients received a graft composed by autologous cortical bone (ACB) and anorganic bovine bone in a ratio of 1:1; the other seven patients received ACB mixed with an allograft in the same ratio. Bone biopsies were obtained 6 months after sinus augmentation at the time of implant placement. Comparative histomorphometrical, histopathological, and immunohistochemical analyses were conducted and statistically analyzed.

RESULTS

After 12 months of functional loading, all implants in both groups were clinical and radiographically successful. Histomorphometrically, although the initial bone formation was not significantly different between groups (new mineralized tissue: 41.03(12.87)% vs. 34.50(13.18)%, p = .620; allograft vs. xenograft groups), the graft resorbed faster in the allograft group (remnant graft particles: 9.83[7.77]% vs. 21.71[17.88]%; p = .026; allograft vs. xenograft groups). Non-mineralized tissue did not statistically differ either (49.00[14.32]% vs. 43.79[19.90]%; p = .710; allograft vs. xenograft groups). The histologic analyses revealed higher cellular content, four times more osteoid lines, and higher vascularization in the xenograft group. Musashi-1 (mesenchymal stromal cell marker) was also more intensively expressed in the xenograft group (p = .019).

CONCLUSIONS

Both composite grafts generate adequate substratum to receive dental implants after healing. Compared with the xenograft composite, allograft composite shows faster turnover and a quicker decrease in biological action after 6 months.

Evaluation of the Anastomosis Canal in Lateral Maxillary Sinus Wall With Cone Beam Computerized Tomography: A Clinical Study

This clinical study used cone beam computerized tomography (CBCT) to locate the position of the anastomosis canal in lateral wall of maxillary sinuses, and to evaluate the thickness of lateral sinus wall and the distance from the lower border of the canal to the sinus floor, which could provide surgeon with information about this anastomosis. Two hundred and forty-two (242) volumes of CBCT scans were included in this study. The distances from the lower border of the anastomosis canal to the sinus floor and from the maxillary alveolar crest to the sinus floor were evaluated in transversal plane, and the thickness of the lateral sinus wall was measured at the distance of 3, 6, 9 mm from the sinus floor and at the level of the lower border of the canal at the same plane. The canal was identified in 87.6% (424/484) of the sinus. Most canals were intraosseous, or beneath the sinus membrane. The mean distance was 9.2 ± 3.5 mm from the lower border of the canal to the sinus floor, and 10.8 ± 4.0 mm from the alveolar crest to the sinus floor. The thickness of the lateral sinus wall was 2.4 ± 0.9 mm, 1.8 ± 0.8 mm, 1.7 ± 0.7 mm, 1.8 ± 0.8 mm at the distance of 3, 6, 9 mm from the sinus floor and at the level of the lower border of the canal. The location of the anastomosis canals varied from each patient, but the distance from the sinus floor was similar in different teeth sites. The sinus floor could be an anatomic landmark of sinus floor augmentation. In order not to interrupt this canal, great care must be taken by the implant surgeon to identify this canal.

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.

The role of angiogenesis in implant dentistry part II: The effect of bone-grafting and barrier membrane materials on angiogenesis

BACKGROUND

In implant dentistry, bone substitute materials and barrier membranes are used in different treatments including guided bone regeneration (GBR), socket preservation, alveolar ridge augmentation, maxillary sinus elevation, and filling bony defects around the inserted dental implant. One of the most important factors in prognosis of treatments using these materials is the growth of new blood vessels in applied areas. Present review was performed to evaluate the effect of the bone-grafting and barrier membrane materials on angiogenesis events.

MATERIAL AND METHODS

An electronic search was performed in PubMed, MEDLINE, and EMBASE databases via OVID using the keywords mentioned in the PubMed and MeSH headings regarding the role of angiogenesis in implant dentistry from January 2000-April 2014.

RESULTS

Of the 5,622 articles identified in our initial search results, only 33 met the inclusion criteria set for this review. Among bone substitute materials the autogenous bone-grafts, and among the barrier membranes the collagenous membranes, had the highest angiogenic potentials. Other bone-grafting materials or membranes were mostly used with pro-angiogenic factors to enhance their angiogenic properties.

CONCLUSIONS

Angiogenesis is one of the key factors, which plays a critical role in success rate of GBR technique and is seriously considered in manufacturing bone-grafting and barrier membrane materials. However, there is still lack of clinical and in-vivo studies addressing the effect of angiogenesis in treatments using bone-grafting and barrier membrane materials.

A case of mandible hypoplasia treated with autologous bone graft from mandibular symphysis: Expression of VEGF and receptors in bone regeneration

The vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) system plays an important role in angiogenesis and osteogenesis during both skeletal development and postnatal bone growth and repair. Indeed, protein expression changes of this system could contribute to craniofacial defects commonly associated with a variety of congenital syndromes. Similarly to other craniofacial bones, mandible arises from neural crest cells of the neuroectodermal germ layer, and undergoes membranous ossification. Here, we report a case of left mandibular hypoplasia in a 42-year-old man treated with autologous bone graft from mandibular symphysis. After 3 months from surgical reconstruction, the protein expression of VEGF and receptors (VEGFR-1, -2 and -3) in regenerated bone tissue was evaluated by immunohistochemistry. At variance with the mandibular symphysis bone harvested for graft surgery, we observed de novo expression of VEGF and VEGFRs in osteoblasts and osteocytes from post-graft regenerating mandible bone tissue. In particular, while VEGFR-1 and VEGFR-3 immunopositivity was widespread in osteoblasts, that of VEGFR-2 was scattered. Among the three receptors, VEGFR-3 was the more intensively expressed both in osteoblasts and osteocytes. These findings suggest that VEGFR-2 might be produced during the early period of regeneration, while VEGFR-1 might participate in bone cell maintenance during the middle or late consolidation period. VEGFR-3 might, instead, represent a specific signal for ectomesenchymal lineage differentiation during bone regeneration. Modulation of VEGF/VEGFR signaling could contribute to graft integration and new bone formation during mandibular regeneration.

Comparative study of BMP-2 alone and combined with VEGF carried by hydrogel for maxillary alveolar bone regeneration

The effect of vascular endothelial growth factor (VEGF) combined with bone morphogenetic protein-2 (BMP-2) for bone regeneration is still controversial as to whether or not VEGF has a synergistic or additive effect. This study attempted to evaluate the synergistic effect of VEGF and BMP-2 compared to BMP-2 alone for maxillary alveolar bone regeneration using collagen sponge/hydrogel complex sheets in a canine model. After mixing BMP-2 and VEGF with a hyaluronic acid-based hydrogel (HAH), the collagen sponge/hydrogel complex was transplanted into maxillary alveolar bone defects (n=14) after the extraction of canine upper first molars on both sides. Bone regeneration was evaluated in three groups (control group without growth factors, experimental groups I and II with BMP-2 alone and BMP-2 and VEGF, respectively) using micro-computed tomography and histological staining. The total amount of new bone formations and bone mineral density were significantly higher in the group with BMP-2 only and the group with BMP-2 combined with VEGF than it in the control group. The area with positive staining of von Willebrand factor bone defect was significantly greater in the group with BMP-2 only and with dual growth factors than the control. BMP-2 released from the HAH promoted new bone formation. However, the combination of BMP-2 and VEGF did not show a synergistic or additive effect on bone regeneration at canine maxillary alveolar bone defects.

Different approaches for interpretation and reporting of immunohistochemistry analysis results in the bone tissue - a review

BACKGROUND

Immunohistochemistry (IHC) is a well-established, widely accepted method in both clinical and experimental parts of medical science. It allows receiving valuable information about any process in any tissue, and especially in bone. Each year the amount of data, received by IHC, grows in geometric progression. But the lack of standardization, especially on the post-analytical stage (interpreting and reporting of results), makes the comparison of the results of different studies impossible.

METHODS

Comprehensive PubMED literature search with a combination of search words "immunohistochemistry" and "scoring system" was performed and 773 articles describing IHC results were identified. After further manual analysis 120 articles were selected for detailed evaluation of used approaches.

RESULTS

Six major approaches to the interpretation and presentation of IHC analysis results were identified, analyzed and described.

CONCLUSIONS

The overview of the existing approaches in evaluation and interpretation of IHC data, which are provided in the article, can be used in bone tissue research and for either better understanding of existing scoring systems or developing a new one. Standard multiparametric, semiquantitative IHC scoring systems should simplify and clarify the process of interpretation and reporting of received data.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_221.

Arteries of the anterior wall of the maxilla in sinus lift surgery

Knowledge of the anatomical course of the anterior maxillary wall and alveolar process arteries is essential for sinus lift procedures. The aim of this study was to analyse the localization of anastomoses between the infraorbital and posterior superior alveolar artery on 101 computed tomography (CT) scans of maxillary sinuses (patients aged 18-70 years). The distance from the anastomosis to the bone point was measured on CT scans for each tooth location; for edentulous patients measurements were made to the lower edge of the alveolar process, and for dentate patients to the neck of the tooth. Measurements were done independently by two observers. The anastomosis analysed was identified on 50% of CT scans. The distance to the anastomosis was longest above the premolar (20.4 mm from tooth cervical line) and shortest above the first molar (15.9 mm to the edge of the alveolar process). The anastomosis can be localized on a CT scan for exact positioning of the antrotomy in 50% of patients. For the remaining patients, the anatomical information provided in this study can be used to reduce the risk of damage to the anastomosis. This study provides information on the distance from the anastomosis to the neck of preserved teeth in partially edentulous patients, which can be used as a reference point during sinus lift procedures.

Sintered anorganic bone graft increases autocrine expression of VEGF, MMP-2 and MMP-9 during repair of critical-size bone defects

This study aimed to evaluate morphometrically the bone formation and immunohistochemically the expression of vascular endothelial growth factor (VEGF) and metalloproteinase (MMP)-2 and -9 during the healing of critical-size defects treated with sintered anorganic bone (sAB). The 8-mm diameter full-thickness trephine defects created in the parietal bones of rats were filled with sAB (test group) or blood clot (CSD-control group). At 7, 14, 21, 30, 90 and 180 days postoperatively (n = 6/period) the volume of newly formed bone and total number of immunolabeled cells (Ntm) for each protein were determined. Bone formation was smaller and faster in the CSD-control group, stabilizing at 21 days (6.74 mm(3)). The peaks of VEGF, MMP-2 and MMP-9 occurred at 7 and 14 days in fibroblasts and osteoblasts, with mean reduction of 0.80 time at 21 days, keeping constant until 180 days. In the test group, sAB provided continuous bone formation between particles throughout all periods. The peak of MMP-2 was observed at 7-14 days in connective tissue cells and for VEGF and MMP-9 at 30 days in osteoblasts and osteocytes. Ntm for VEGF, MMP-2 and MMP-9 were in average, respectively, 3.70, 2.03 and 5.98 times higher than in the control group. At 180 days, newly formed bone (22.9 mm(3)) was 3.74 times greater in relation to control. The physical and chemical properties of sAB allow increased autocrine expression of VEGF, MMP-2 and MMP-9, favoring bone formation/remodeling with very good healing of cranial defects when compared to natural repair in the CSD-control.

The use of injectable sonication-induced silk hydrogel for VEGF(165) and BMP-2 delivery for elevation of the maxillary sinus floor

Sonication-induced silk hydrogels were previously prepared as an injectable bone replacement biomaterial, with a need to improve osteogenic features. Vascular endothelial growth factor (VEGF(165)) and bone morphogenic protein-2 (BMP-2) are key regulators of angiogenesis and osteogenesis, respectively, during bone regeneration. Therefore, the present study aimed at evaluating in situ forming silk hydrogels as a vehicle to encapsulate dual factors for rabbit maxillary sinus floor augmentation. Sonication-induced silk hydrogels were prepared in vitro and the slow release of VEGF(165) and BMP-2 from these silk gels was evaluated by ELISA. For in vivo studies for each time point (4 and 12 weeks), 24 sinus floors elevation surgeries were made bilaterally in 12 rabbits for the following four treatment groups: silk gel (group Silk gel), silk gel/VEGF(165) (group VEGF), silk gel/BMP-2 (group BMP-2), silk gel/VEGF(165)/BMP-2 (group V + B) (n = 6 per group). Sequential florescent labeling and radiographic observations were used to record new bone formation and mineralization, along with histological and histomorphometric analysis. At week 4, VEGF(165) promoted more tissue infiltration into the gel and accelerated the degradation of the gel material. At this time point, the bone area in group V + B was significantly larger than those in the other three groups. At week 12, elevated sinus floor heights of groups BMP-2 and V + B were larger than those of the Silk gel and VEGF groups, and the V + B group had the largest new bone area among all groups. In addition, a larger blood vessel area formed in the remaining gel areas in groups VEGF and V + B. In conclusion, VEGF(165) and BMP-2 released from injectable and biodegradable silk gels promoted angiogenesis and new bone formation, with the two factors demonstrating an additive effect on bone regeneration. These results indicate that silk hydrogels can be used as an injectable vehicle to deliver multiple growth factors in a minimally invasive approach to regenerate irregular bony cavities.

Hyaluronic acid stimulates neovascularization during the regeneration of bone marrow after ablation

Restoration of vasculature is a critical component for successful integration of implants in musculoskeletal tissue. Sodium hyaluronate (NaHY) has been used as a carrier for demineralized bone matrix (DBM). DBM is osteoinductive and osteoconductive, but whether NaHY by itself has an effect is not known. NaHY has been reported to promote neovascularization, suggesting it may increase neovasculature when used with DBM as well. To test this, we used a rat tibial marrow ablation model to assess neovascularization during bone formation and regeneration of marrow with different combinations of NaHY alone and NaHY+DBM. To assess neovascularization during normal healing, animals were euthanized at 3-, 6-, 14-, 21-, and 28-days post-ablation, and the vasculature perfused using a radio-opaque contrast agent. Vascular morphology was assessed using μCT and histology. Peak vessel volume within the marrow cavity was observed on day-14 post-ablation. Test materials were injected into the ablated marrow space as follows: (A) empty defect controls; (B) high MW (700-800 kDa) NaHY + heat inactivated DBM; (C) DBM in PBS; (D) low MW NaHY (35 kDa) + DBM; (E) high MW NaHY + DBM; (F) D:E 50:50; (G) low MW NaHY; (H) high MW NaHY; and (I) G:H 50:50. Neovascularization varied with bone substitute formulation. μCT results revealed that addition of NaHY resulted in an increase in vessel number compared to empty defects. Total blood vessel volume in all NaHY only groups were similar to DBM alone. Histomorphometry of sagittal sections showed that all three formulations of NaHY increased blood vessel number within the marrow cavity, confirming that NaHY promotes neovascularization.

Engineered bone by autologous osteoblasts on polymeric scaffolds in maxillary sinus augmentation: histologic report

Several regenerative therapies have been used for maxillary sinus grafting. However, recent advances in modern bone tissue engineering techniques have been evaluated. The aim of this histologic report was to evaluate the bone obtained by a culture of autogenous osteoblasts seeded on polyglycolic-polylactid scaffolds in maxillary sinus augmentation. A 56-year-old partially edentulous male with severe atrophy of the posterior maxilla received 6 polyglycolid-polylactid disks (8 mm diameter × 2 mm depth, Oral Bone), each carrying 1.5 million autogenous osteoblasts into the depth of the sinus cavity. After 6 months healing, a bone core was harvested and histologically evaluated. The augmented maxillary sinus with engineered bone presented a mean of 28.89% and 71.11% of bone and medullary spaces, respectively. Data from this case report demonstrate that the newly formed bone provided by engineered bone tissue allowed proper initial stability for dental implant placement. However, the role of this new bone in the long-term success of dental implant anchorage needs further investigation.

Combining scaffolds and osteogenic cells in regenerative bone surgery: a preliminary histological report in human maxillary sinus augmentation

PURPOSE

The following case series evaluated the maxillary sinus augmentation responses to tissue-engineered bone graft obtained by a culture of autogenous osteoblasts seeded on polyglycolic-polylactic scaffolds and calcium phosphate.

MATERIALS AND METHODS

Sinus floor augmentation was performed bilaterally in five patients (mean age 58.4 years) with tissue-engineered bone (test site - Oral Bone, BioTissue, Freiburg, Germany) or calcium phosphate (control site - Biocoral, Novaxa Spa, Milan, Italy). Biopsies were harvested 6 months after sinus augmentation for histometric evaluation. Volumetric measurements were taken at baseline and 6 months after the surgical procedure.

RESULTS

The mean of vertical bone gain was 6.47 +/- 1.39 mm and 9.14 +/- 1.19 mm to test and control sites, respectively. The histological sections depicted mature bone with compact and cancellous areas. All biopsies contained varying percentages of newly formed bone and marrow spaces. The mean of bone tissue in the grafted area was 37.32 +/- 19.59% and 54.65 +/- 21.17% for tissue-engineered bone and calcium phosphate, respectively.

CONCLUSION

Within the limits of the present report, the histological data in humans confirmed that tissue-engineered bone and calcium phosphate allowed newly formed bone after maxillary sinus augmentation.