Bone healing in critical-size defects treated with either bone graft, membrane, or a combination of both materials: a histological and histometric study in rat tibiae

Objectives: The aim of the present investigation was to histologically analyze the effect of using lyophilized bovine bone (GenOx^® organic matrix) with (or without) guided tissue regeneration (using a decalcified cortical osseous membrane [GenDerm^®]) on bone healing in surgically created critical‐size defects created in rat tibia. Material and methods: Surgical critical‐size bone defects were created in 64 animals that were randomly divided into four groups: group I (control); group II (defect filled with GenOx^®); group III (defect covered by GenDerm^®); group IV (defect filled with GenOx^® and covered by GenDerm^®). Animals were killed at 30 or 90 days post‐surgery. The specimens were embedded in paraffin, serially cut, and stained with hematoxylin and eosin for analysis under light microscopy. The formation of new bone in the cortical area of the defect was histomorphometrically evaluated. Results: All experimental groups demonstrated superior bone healing compared with the control group. However, group IV samples showed evidence of more advanced healing at both 30 and 90 days post‐surgery as compared with the other experimental groups. Conclusions: The bovine organic bone graft GenOx^® associated with GenDerm^® this produced the best treatment results in the case of critical‐size defects in rat tibia. To cite this article :
Bernabé PFE, Melo LGN, Cintra LTA, Gomes‐Filho JE, Dezan E Jr, Nagata MJH. Bone healing in critical‐size defects treated with either bone graft, membrane, or a combination of both materials: a histological and histometric study in rat tibiae.
Clin. Oral Impl. Res. 23 , 2012; 384–388.
doi: 10.1111/j.1600‐0501.2011.02166.x     

A comparative study of barrier membranes as graft protectors in the treatment of localized bone defects. An experimental study in a canine model

Guided bone regeneration is a predictable and well-documented surgical approach for the treatment of deficient alveolar ridges prior to endosseous implant placement. The purpose of this study was to compare a new resorbable membrane (GORE RESOLUT ADAPT Regenerative Membrane, i.e. 67% glycolide (PGA) : 33% trimethyline carbonate (TMC)) with Bio-Gide, a resorbable collagen membrane. Five canines were used in the study. Three saddle-type osseous defects were created bilaterally in edentulous areas of the mandible. The defects were filled with assayed, canine demineralized freeze-dried bone (DFDB) in a thermoplastic gelatin matrix. Using a randomized block design, four sites were covered with PGA : TMC membranes of four different porosities, one site was covered with a collagen membrane and one site consisted of DFDB alone (control). At 3 months, the animals were euthanized and the mandibles were removed en bloc for laboratory processing. A total of 30 sites were reviewed microradiographically and underwent histomorphometric analysis for bone regeneration, soft tissue presence and remaining graft material. All sites exhibited uneventful healing. A significantly higher percentage of bone regeneration was seen in the sites protected by the PGA : TMC membrane. A higher component of soft tissue was visible beneath the collagen membrane as compared with the PGA : TMC membrane. The control sites exhibited noticeable deformation of the regenerated bone secondary to collapse of the overlying periosteum. The authors conclude that the PGA : TMC membrane protected the DFDB-filled defect and allowed a greater amount of bone regeneration than the defect protected by the collagen membrane or the control.     

An isolation and in vitro culturing method for human intraoral bone cells derived from dental implant preparation sites

In dental implantology, the biocompatibility of the osseous tissue to the implant surface and to local environmental factors plays an important role in the process of healing. Bone cells derived from intraoral osseous tissue proves to be an important source of the osteoprogenitor cells required for healing of the petiodontium around implants. Historically, the rat calvaria model has been employed to study the effects of various dental treatments on bone in Vito. However, there are morphological and functional differences which exist between bone cells derived from rat calvaria and human intraoral osseous tissue that impose certain limitations on the usefulness of the rat calvaria model for dental implant applications. Therefore, an in vitro culturing method for the isolation, growth and maintenance of human intraoral bone cell cultures derived from osseous tissues is truly warranted. In addition, a method for the accurate characterization of these bone cells as osteoblasts is also vital. The specific objective of this study was to establish isolation and in vitro culturing methods utilizing human intraoral bone cells derived from dental implant preparation sites. This paper describes techniques for the harvesting of human bone cells from the intraoral derived osseous tissues and discuss the procedures for maintaining the primary intraoral bone cell culture. In addition, our studies utilize established protocols for the characterization of these cells as osteoblasts by means of alkaline phosphatase activity determination, identification of cellular osteonectin and osteocalcin antigens, establishing the presence of cells expressing type I collagen and determining the ability of cells to produce calcifications. The utilization of intraoral osseous tissue may prove useful for future dental implant research by providing an in vitro model system more closely related to conditions encountered clinically.     

Bone remodelling after regenerative procedures around implants placed in fresh extraction sockets: an experimental study in Beagle dogs

Introduction: After a tooth extraction, the height of the buccal wall tends to decrease. The literature indicates that regenerative techniques (guided bone regenerative [GBR] techniques) have succeeded in improving the bone levels. Therefore, this experiment set out to compare the physiological bone remodelling in Beagle dog models after implant placement in a fresh extraction socket, with and without the application of regenerative procedure. Materials and methods: Five dogs were used in this study. Test and control sites were randomly selected. The experimental teeth (fourth pre‐molar and first molar) were hemi‐sected removing the distal roots and placing implants. Porcine bone was placed to fill the gap around the implant on the test sites and a reabsorbable membrane was used to cover the area. The dogs were put down at different times (2 weeks, 1 month and 3 months). The measurements were taken immediately and at 2, 4, 12 weeks after implant placement. Student's test for paired data was used to compare the means of the clinical measurements. Results: At 2 weeks: On the control sites, few signs of resorption were detected at the first molar only, while at the test sites bone levels were placed at the implant shoulder or above. At 4 weeks: On the control site, slight bone remodelling was observed, while on the test site minor signs of resorption or an increase of bone levels were detected. At 12 weeks: The alveolar crest on the control sites showed various degrees of remodelling. On the test sites stable bone levels or an increase of bone crest was observed. Conclusion: With the limits of this study, the findings showed that GBR techniques were able to limit resorption of the alveolar crest after tooth extraction. A pattern of bone remodelling after tooth extraction and implant placement was observed in the control sites (no GBR) as well as in test sites (GBR), and although the exact cause of this is unclear, surgical trauma could play a role. Further studies are necessary to confirm these results and to clarify the precise causes of bone remodelling in fresh extraction sockets. To cite this article:
Barone A, Ricci M, Calvo‐Guirado JL, Covani U. Bone remodelling after regenerative procedures around implants placed in fresh extraction sockets: an experimental study in the Beagle dogs.
Clin. Oral Impl. Res. 22 , 2011; 1131–1137
doi: 10.1111/j.1600‐0501.2010.02084.x     

Gore-Tex 膜引导骨再生技术在种植体周围炎治疗中的应用

目的：评价Ｇｏｒｅ－Ｔｅｘ膜引导骨再生技术治疗种植体周围炎的临床疗效。方法：对３例种植体周围炎患者局部冲洗和药物治疗控制感染后行翻刮治，应用Ｇｏｒｅ－Ｔｅｘ膜覆盖缺损，术后６月去除膜，摄Ｘ线片及进行临床评价。结果：３例骨缺损者均完全再生修复，种植体稳定。结论：局部冲洗和翻瓣刮治后，应用Ｇｏｒｅ－Ｔｅｘ膜覆盖骨缺损治疗种植体周围炎，可获得骨组织再生修复。     

The role of cortical perforations in bone regeneration: a systematic review

The aim of this review was to determine the effect of cortical perforations in bone regeneration considering the surgical technique. An electronic search in the PubMed (MEDLINE) and ScienceDirect databases and a hand search of the literature was conducted covering the period July 2008 to December 2018. Studies that specified the creation of perforations in the recipient area as a study variable associated with the regenerative technique were included. The quality of the randomized clinical trials included in this systematic review was also assessed. A total of 16 articles met both inclusion criteria and were eligible for analysis. Studies were grouped into three blocks according to the associated surgical technique. All studies were performed in an experimental model except for one. Qualitative assessment of the studies showed a moderate to high risk of bias of the overall studies. The evidence for creating perforations in guided bone regeneration and also in combination with autologous bone blocks in order to increase bone formation is limited according to the publications analysed. Although the number and size of perforations do not appear to interfere with the result, their effect in the upper maxilla and in the mandible should be evaluated separately due to the structural anatomical differences.     

Comparative osteogenesis of maxilla and iliac crest human bone marrow stromal cells attached to oxidized titanium: a pilot study

Objectives: Severe alveolar bone loss affects dental implant placement. Bone augmentation by grafting iliac crest bone rich in osteoprogenitor cells such as bone marrow stromal cells (BMSCs) requires a second surgical procedure in non‐orofacial bone. Skeletal site‐specific osteogenesis indicates maxilla and mandible BMSCs are highly proliferative and exhibit osteogenic properties superior to iliac crest BMSCs. Alveolar bone can be easily obtained during routine dental surgery, but it is unclear if titanium‐attached alveolar BMSCs will retain their superior osteogenic properties. This study evaluated and compared in vitro osteogenic properties of titanium‐attached maxilla and iliac crest BMSCs in same individuals. Material and methods: Primary culture of maxilla and iliac crest BMSCs from four normal healthy volunteers was expanded in culture. In 24‐well plates, first passage BMSCs were seeded directly (1 × 10⁴ cells/well) on oxidized titanium disks (1.27 cm diameter and 2 mm thickness) or tissue culture plate. Each cell type was assessed for affinity for titanium, post‐attachment survival and osteogenic differentiation based on alkaline phosphatase and osteopontin expressions. Results: There was no difference in the affinity of maxilla and iliac crest BMSCs to titanium. However, titanium‐attached maxilla BMSCs were apparently more osteogenically responsive than iliac crest cells based on calcium accumulation and gene expression of alkaline phosphatase and osteopontin. But these differences were not statistically significant in this small patient sample. Conclusion: Maxilla and iliac crest BMSCs have similar attachment affinity for titanium. This pilot study indicates that titanium‐attached maxilla BMSCs are more osteogenically responsive and may be a viable and more readily available donor graft material in implant dentistry.     

Evaluation of guided tissue regeneration in interproximal defects

Abstract This study clinically evaluates the use of expanded polytetrafluoroethylene (ePTFE) membranes with or without the addition of decalcified freeze-dried hone allograft (DFDBA) in the treatment of interproximal intraosseous defects, 25 patients (26 paired defects) diagnosed with advanced periodontitis and having at least 2 bilateral interproximal probing depths of s6 mm participated in the study. After the hygiene phase, measurements were made to determine soft tissue recession, pocket depth, and clinical attachment levels. Defects from each pair were randomly treated with either ePTFE alone (control), or ePTFE + DFDBA (experimental). Measurements were made during the surgery to determine crestal resorption, defect resolution and defect fill. Membranes were removed at 4 to 6 weeks. At 6 months, the soft and hard tissue measurements (surgical reentry) were repeated. Both groups showed statistically significant improvement when compared to baseline (p<0.001), but no difference was determined between groups. Control sites showed a 50% bone fill and experimental sites had 54% bone fill. The defect resolution changes were also similar between control and experimental groups, respectively (80%, 74%). For this short-term study, it was concluded that either technique was beneficial for the treatment of intraosseous defects. Other studies are needed to assess the long-term stability of the improvements rendered by these treatments.     

Intra-oral bone harvesting: two methods compared using histological and histomorphometric assessments

Aim: This study used morphometric analyses to compare two methods for the intra‐oral harvesting of particulate bone: Mectron Piezosurgery® and the Meta Micross®. Materials and methods: Twenty patients requiring bilateral germectomy of the lower third molars for orthodontic reasons were selected and a sample was harvested from each patient from a standardised donor site (the cortical bone in the area of the retromolar triangle). Ten samples were obtained for each method. The particulate collected were subjected to a histological examination and the samples were analysed considering the following parameters: the mean surface area of fragments, the mean surface area considered vital and the mean surface area considered non‐vital, the mean percentage of area considered vital and the mean percentage of area considered non‐vital, the mean number of normal osteocytes and the mean number of osteocytes with morphological changes identified per unit area (600,000 μm²). The results were analysed, calculating the mean and the corresponding standard deviations, and testing their significance using Student's t‐test, and plotted in graphs. Results: Mectron Piezosurgery® produced significantly larger particles (P<0.05) than the Meta Micross®, with a larger mean surface area considered vital and a significantly larger (P<0.05) surface area considered non‐vital. Mectron Piezosurgery® also produced a smaller mean percentage of area considered vital (64.83%) and a larger mean percentage of area considered non‐vital (35.17%) by comparison with the Meta Micross® (75.34% and 24.66%, respectively). The data also showed that the two methods produce a similar quantity of empty lacunae, and that the Mectron Piezosurgery® produces a larger quantity of osteocytes. Conclusions: The analyses conducted demonstrated that the particulate collected with the Meta Micross® had a smaller mean surface area of the fragments and a smaller surface area of bone considered non‐vital than in the particulate collected using Mectron Piezosurgery®. To cite this article:
Bacci C, Lucchiari N, Valente M, Della Barbera M, Frigo AC, Berengo M. Intra‐oral bone harvesting: two methods compared using histological and histomorphometric assessments. Clin. Oral Impl. Res. 22 , 2011; 600–605.
doi: 10.1111/j.1600‐0501.2010.02022.x     

Osteogenesis by guided tissue regeneration and demineralized bone matrix

AIM: To evaluate in a discriminating capsule model whether bone formation by guided tissue regeneration (GTR) may be influenced by concomitant implantation of demineralized bone matrix (DBM). MATERIALS AND METHODS: Thirty 4-month-old male albino rats of the Wistar strain were used in the study. Following surgical exposure of the mandibular ramus, a hemispherical, Teflon capsule (5.0 mm in diameter), loosely packed with a standardized amount of DBM, was placed with its open part facing the lateral bone surface of the ramus. At the contralateral side, an empty capsule was placed, serving as control. After healing periods of 15, 30, and 120 days, groups of 10 animals were sacrificed and 40-70 microm thick undecalcified sections of the capsules were produced. In the sections, the cross-sectional areas of (1) the space created by the capsule, (2) newly formed bone, (3) DBM particles, (4) loose connective tissue as well as the (5) height of the capsules, and (6) that of the newly formed bone were measured. RESULTS: Increasing bone fill was observed in both test and control sites from 30 to 120 days. After 30 days of healing, the mean amount of bone was approx. 3% of the cross-sectional area of the capsules at the test sites while it was 8% in the control sites (p<0.05). However, no statistically significant differences were observed between the test (46%) and control (64%) sites after 120 days regarding any of the measured parameters (p>0.05). The newly formed bone in the DBM group at 120 days, on the other hand, appeared more dense than that in the control capsules. CONCLUSION: DBM used as an adjunct to GTR did not provide any added effect on bone formation but increased the density of the newly formed bone.     

骨移植材料有效骨再生的评价方法及应用

随着科学技术的迅猛发展,学者们对各种各样的骨移植材料进行大量探索、研究和开发。评价骨移植材料有效骨再生的方法亦随之越来越多。其检测技术各有侧重,从不同的角度表现生物材料有效骨形成的能力。本文将从影像学检测、组织学观察、生化指标测定和移植骨生物力学等几个方面对骨移植材料有效成骨的评价方法、各种相关检测技术和指标作一综述。     

Influence of PRP on autogenous sinus grafts. An experimental study on sheep

Since platelet -rich plasma (PRP) has been introduced to the field of oral surgery, it has become a widely accepted additive for bone regeneration treatment. The aim of this study was to evaluate the regenerative capacity of PRP in a sinus graft study on sheep. Twelve adult sheep underwent a bilateral sinus floor elevation procedure with cancellous bone from the iliac crest. Unilaterally, PRP was administrated to the bone graft. After 4 (six sheep) and 12 weeks (six sheep), bone biopsies were obtained from each site. With histomorphometric analysis we evaluated both the percentage of newly formed bone within the grafted site and the percentage of the contact area between the grafted bone and the newly formed bone. After 4 weeks the mean proportion of newly formed bone on the control side was 26.1%, whereas it was 29.2% on the test side. After 12 weeks it was 46.9% on the control side and 51.1% on the test side. The area of contact between the graft and the newly formed bone was 73.0% on the control side and 78.5% on the test side after 4 weeks, and 87.2% on the control side and 90.1% on the test side after 12 weeks. A statistical analysis did not reveal significant differences between the control and the test side. The results of the present experimental study show a regenerative capacity of PRP of quite low potency. Further basic research is needed to investigate more profoundly the possibilities of PRP in bone regeneration.     

新型骨替代材料羟基聚磷酸钙钠的组织学实验研究

羟基聚磷酸钙钠是一种新型无机高分子材料,它具有与骨组织进行能量与物质交换的能力,骨于骨组织缺损的修复。目的：考察ＨＰＡ植入骨组织后其界面形成情况。方法采用鼠胫骨内植入ＨＰＡ,光镜下考究其组织反应情况,并与羟基磷灰石和钛合金引起的组织反应相比较。结果：发现不同种类的生物材料直接影响界面区早期的组织反应,ＨＰＡ比产早地引起了新骨形成,结论ＨＰＡ一种理想的骨组织替代材料。     

S-nitroso albumin enhances bone formation in a rabbit calvaria model

Nitric oxide (NO) is a mediator involved in bone regeneration. We therefore examined the effect of the novel NO donor, S-nitroso human serum albumin (S-NO-HSA) on bone formation in a rabbit calvaria augmentation model.Circular grooves (8 mm diameter, two per animal) were created by a trephine drill in the cortical bone of 40 rabbits and titanium caps were placed on the rabbit calvaria bone filled with a collagen sponge soaked with either 100 μL S-NO-HSA (5%, 20%) or human albumin (5%, 20%). After 4 weeks the titanium hemispheres were subjected to histological and histomorphometric analysis. Bone formation and the volume of the residual collagen sponge were evaluated.S-NO-HSA treatment groups had a significantly higher volume of newly formed bone underneath the titanium hemispheres compared to the albumin control groups (5%: 15.5 ± 4.0% versus 10.6 ± 2.9%; P < 0.05; 20%: 14.0 ± 4.6% versus 6.0 ± 3.8%; P < 0.01). The volume of residual collagen sponge was also significantly lower in the S-NO-HSA groups compared to the control groups (5%: 0.4 ± 0.5% versus 2.6 ± 2.4%; P < 0.05 and 20%: 1.5 ± 2.7% versus 13.0 ± 18.7%; P < 0.01).This study demonstrates for the first time that S-NO-HSA promotes bone formation by slow NO release. Additionally, S-NO-HSA increases collagen sponge degradation.     

Feasibility of using allograft bone with resorbable collagen membrane for alveolar ridge vertical defect augmentation for dental implant placement in Patient with Aggressive Periodontitis: A case report

Purpose

This case report demonstrates the feasibility of using allograft bone with a resorbable collagen membrane to correct an alveolar ridge defect and achieve a highly esthetic restoration.