Trephine Bur Research Articles

Improvements of alveolar bone healing using Moringa oleifera leaf powder and extract biomimetic composite: an experimental study in dogs

Alveolar ridge preservation techniques and biomaterials were extensively used in the past few years. The rate of new bone formation is the concept in healing sockets. The faster the rate the lesser the alveolar bone resorption. Resorption is fastened in the first three months after extraction. Wide range of biomaterials were available, the choice of an ideal material was confusing.Objective: Evaluate the effectiveness of both Moringa Oleifera (MO) leaf powder and extract mixture locally and MO leaf extract repeated injections in fresh extraction sockets of dog. Moreover, identifying bioactive phenolic compounds in dried leaves.Materials and Methods: Eight mongrel dogs were included in this study; two animals were used as control. Six test animals were divided into two groups according to biopsy time (3 and 5 weeks). Each of these groups includes three animals. All animals were subjected to extraction of the third premolar bilaterally, both sides of the test animals (the six) were treated with Moringa Oleifera leaf powder (0.7 gm) and water extract (1ml) mixture. The right side only was subjected to repeated injections of Moringa Oleifera leaf water extract (½ ml) for two times (1st week and 2nd week postoperatively for all groups). Trephine bur was used to take biopsy for the purpose of histopathologic examination by H&E and Masson Trichrome stain to quantify new bone formation, and number of inflammatory cells.Results: Bone area percent showed the highest mean value in the right side at 3 weeks and 5 weeks. ANOVA test revealed no significant difference between groups (P=0.43) at 3 weeks, while the difference was significant at 5 weeks (P=0.00). Mean inflammatory cells count were significantly higher mean value in control group at 3 weeks and 5 weeks (P=0.00). Conclusion: Two injections of moringa oleifera aqueous extract of 11.7% concentration improved bone area present significantly at 5 weeks and decreased inflammatory cells at all test periods.

Histological and Histomorphometric Analyses of Two Bovine Bone Blocks Implanted in Rabbit Calvaria

This study compared the osteogenic potential of two types of bovine bone blocks. Blocks were obtained by either sintered or a nonsintered process. Calvaria were surgically exposed in 20 rabbits. In each animal, six 0.5-mm-diameter cortical microperforations were drilled with a carbide bur before grafting to promote graft irrigation. The sintered (group 1) and nonsintered (group 2) bovine bone blocks (6 mm diameter, 5 mm high) were bilaterally screwed onto calvarial bone. Blocks were previously prepared from a larger block using a trephine bur. Rabbits were sacrificed after 6 and 8 weeks for the histological and histomorphometric analyses. Samples were processed using the historesin technique. The quantitative and qualitative analyses of the newly formed bone were undertaken using light microscopy. Both groups showed modest new bone formation and remodeling. At the 8-week follow-up, the sintered group displayed significantly lower bone resorption (average of 10% in group 1 and 25% in group 2) and neo-formation (12.86 ± 1.52%) compared to the nonsintered group (16.10 ± 1.29%) at both follow-ups (p < 0.05). One limitation of the present animal model is that the study demonstrates that variations in the physico-chemical properties of the bone substitute material clearly influence the in vivo behavior.

Antimicrobial action of photodynamic therapy in root canals using LED curing light, curcumin and carbopol gel.

To evaluate the capacity of carbopol gel to maintain the intensity of a LED curing light (blueLED) along the length of prepared root canals in bovine teeth, and to assess the antimicrobial capacity of curcumin photoactivated by a LED curing light in the presence of carbopol gel. Experiment 1: Eight straight roots of bovine incisors were standardized to a length of 15mm, and the root canals instrumented up to a size 120K-file. The LED curing light was irradiated inside the root canals using an aluminium collimator (1.5mm in diameter) placed at the orifice (n=8). Initially, the irradiation was performed in empty root canals and then repeated with the root canals filled with carbopol gel. Simple standardized photographs of the roots were taken with a digital camera in the mesial perspective during the irradiation procedure and the images analysed in OriginLab software to verify the light intensity along the length of the root. Experiment 2: Twenty dentine blocks were obtained from the cervical third of bovine incisors using a trephine bur. Biofilms were induced for 21days on the blocks using Enterococcus faecalis (ATCC 4083) at 109 cellsmL-1 . The blocks were treated according to the groups (n=5): positive control; standard PDT (methylene blue+diode Laser); curcumin; LED curing light; and curcumin+LED curing light. After the treatment, the samples were dyed with Live/Dead BacLight Bacterial Viability solution and fluorescence images were obtained by Confocal Scanning Laser Microscopy (CSLM). Experiment 3: Thirty-two roots of bovine incisors were prepared as described in experiment 1. Their dentinal tubules were contaminated and the root canals treated according to the groups (n=8): positive control; standard PDT; curcumin+LED curing light; curcumin+carbopol gel+LED curing light. The specimens were sectioned longitudinally and the split roots were treated with the Live/Dead dye to obtain fluorescence images by CSLM. All images were processed using BioImageL software to measure the percentage of viable bacteria and the data analysed statistically using the nonparametric Kruskal-Wallis test (α<0.05). In Experiment 1, carbopol gel did not improve the intensity of LED light transmission along the root canal. In Experiment 2, a significant decrease (P<0.05) in bacterial viability occurred in the following order: positive control<only LED curing light<only curcumin<curcumin+LED curing light=standard PDT; and in Experiment 3 positive control=curcumin+LED curing light≤curcumin+gel+LED curing light≤standard PDT. Similar disinfection effectiveness was obtained using curcumin+LED curing light and methylene blue+660nm LASER (standard PDT). The use of carbopol gel did not favour a greater transmission of LED light along the root canal and also resulted in less bacterial killing when used in endodontic PDT.

Histologic and Histomorphometric Assessment of Xenograft Bone Substitute versus Synthetic Nonceramic Hydroxyapatite for Canine Tooth-Socket Preservation.

This study sought to histologically and histomorphometrically assess and compare application of xenograft bone substitute and synthetic nonceramic hydroxyapatite for tooth-socket preservation in dogs. This split-mouth clinical trial was conducted in five hybrid dogs, using four tooth sockets in each dog, with a total of 20 sockets for evaluation. Group 1 received xenografts, and group 2 received synthetic nonceramic hydroxyapatite in the sockets. In group 3 (positive controls), sockets remained empty. All sockets were covered with collagen resorbable membrane, and the flap was stitched using nonresorbable sutures. In group 4 (negative control), sockets were without membrane, left empty, and sutured. After 12 wk, 8-mm-high bone core biopsies were harvested from inside the sockets, using a trephine bur with an internal diameter of 2 mm. We assessed the tissue in terms of percentage of newly formed viable bone, percentage of remaining particles, degree of inflammation, and type of connective tissue. Data were statistically analyzed. The percentage of newly formed viable bone was 34.98% in group 1 and 41.30% in group 2, and this difference was not statistically significant (p = 0.710). The percentage of remaining particles was 15.95% in group 1 and 14.14% in group 2; this difference was also not statistically significant (p = 0.902). Both synthetic nonceramic hydroxyapatite and xenograft bone substitute showed similar efficacy, histologically and histomorphometrically, when used with resorbable collagen membrane for tooth-socket preservation in dogs.

A Step-by-Step Procedure for Bone Regeneration Using Calcium Phosphate Scaffolds: From Site Preparation to Graft Placement.

Hydroxyapatite (HA) is the main mineral component of bone and teeth. HA is often used as a bone substitute and especially in its granular form it is osteoconductive and osseointegrating as shown by many investigations in animals and humans. HA granules are used for filling bone defects, but they have poor handling qualities and retention at the surgical site, leading to graft voids between the granules and bone tissue and resulting in mechanical instability. Furthermore HA implantation is not constantly followed by favorable results, especially when it is carried out for augmentation of the alveolar ridge. This article offers a protocol for bone reconstruction and predictable implant treatment outcomes. We provide a step-by-step description of both the recipient site and composite graft preparations using coralline HA granules (CHAG) and homologous fibrin glue (HFG). In the present study, 20 randomly selected patients (12 women and 8 men) underwent bone regeneration using CHAG-HFG before a dental implant procedure. Radiographic imaging, physical examination, and histological analysis were performed during a 2-year period. Biopsies were obtained at second-stage surgery before implant insertion using a 2.8-mm trephine bur. A morphological study of 20 bioptic human specimens was performed. Our results demonstrate that this surgical protocol for the preparation of the recipient site associated with a mixture of coralline HA granules with homologous fibrin glue provides reliable bone regeneration, thus reducing failures and minimizing risks of postoperative morbidity.

Experimental Study of Bone Defect Repair Using Centrifuged and Non-Centrifuged Bone Marrow Aspirate

Purpose this study was conducted between 2015 and 2017 at the faculty of Veterinary Medicine Cairo University and aimed to histologically compare between the effect of processed and unprocessed bone marrow aspirate on the quantity and quality of the newly formed bone. Material and methods 72 Adult male white New Zealand rabbits were used in this study and were divided equally into 2 groups A and B. Bone defects were created at the medial upper extremity of right and left tibia of all rabbits down to bone using trephine bur measuring 4 mm diameter to 5 mm depth. The bone defects were treated with whole bone marrow loaded on gel foam in group A right tibias and using mononuclear cell layer obtained through centrifuging bone marrow loaded on gel foam in group B right tibias. Bone defects in the left tibias in all rabbits treated with gel foam only. Scarification was done 3,6,12 weeks postoperative. Histological evaluation was done using H and E and Masson’s trichrome stain. Results the results showed that group A right tibial defects had better healing results than group B right tibial defects all over the follow-up period, but the differences were not statically significant. Conclusion the study findings indicate that the centrifugal concentration techniques provide better therapeutic outcomes over the whole BMA, but it is statistically insignificant.

EFFECT OF AUTOGENOUS BONE MARROW MESENCHYMAL STEM CELLS IN HEALING OF MANDIBULAR OSSEOUS DEFECTS GRAFTED WITH BETA TRICALCIUM PHOSPHATE IN DOGS

INTRODUCTION: Bone defect above critical size does not heal completely by itself and thus represents major clinical challenge to reconstructive surgery. Tissue engineering is a new approach for the repair of osseous defects. β tricalcium phosphate (β-TCP) loaded with autogenous bone marrow derived mesenchymal stem cells (BMSCs) is suggested to have a promising osteogenic characteristics that support its potential in tissue engineering to repair bone defects. OBJECTIVES: was to evaluate the efficacy of autogenous (BMSCs) by its transplantation into local defects using (β-TCP) as a carrier. MATERIALS AND METHODS: Ten male Mongrel dogs weighing 25 Kg were used in this study. Right and critical size bone defects (CSDs) were performed intraorally at the mandibular premolar area by the aid of trephine bur, of 6mm outer diameter and 5mm inner diameter. Right side bone defects (Experimental) were filled with mixture of (β-TCP) and (BMSCs) which was taken from bone marrow aspirate concentrates (BMACs) from the same animal. Meanwhile, the left side bone defects (control) were left empty for healing spontaneously. The effect of (BMSCs) was assessed histologically as well as histomorphometrically after 6 weeks. RESULTS Greater amount of bone formation was noticed in (CSDs) filled with (β-TCP) and (BMSCs). The amounts of new bone formed in the defects filled with (β-TCP) and (BMSCs) were significantly greater than those formed within the defects that were left empty. CONCLUSIONS: Autogenous (BMSCs) has excellent osteogenic characteristics and can be added to bone grafts following surgical and periodontal surgeries to enhance bone regenerative capacity.

A Step-By-Step Technique for the Piezosurgical Removal of Fractured Implants.

With the increasing popularity of dental implants, the removal of fractured implants has become a major challenge for clinicians. Several tools can be used for the removal of osseointegrated implants; however, few of these have the characteristics of easy control, selective cutting, and rapid healing. In this study, the authors describe a step-by-step technique for the removal of osseointegrated fractured implants via multiple peri-implant osteotomies performed using a piezoelectric device and appropriate inserts. All patients ended with primary wound closure without any soft tissue dehiscence and no healing problems during the postoperative period. As the use of ultrasonic inserts enables precise and selective cuts, piezosurgical implant removal is an attractive alternative to trephine burs or rotary drills.

Bone marrow aspirate versus two bone autograft types in reconstruction of alveolar cleft: A histomorphometric analysis

Objectives: The aim of this study was to compare histomorphometrically between bone marrow aspirate on a collagen carrier with autogenous bone grafts harvested from two different donor sites in alveolar cleft defect repair.Materials and Methods: eighteen patients with alveoalar cleft defect were included in the study. Twelve out of eighteen patients were reconstructed with auotogenous bone graft; six patients grafted with illium bone graft and six patients grafted with chin bone graft. The remaining patients out of eighteen were reconstructed using bone marrow aspirate implanted on a collagen carrier. Six months after grafting, bone specimens from augmented alveolar ridge sites were retrieved by trephine burs for histomorphometric analysis. Results: Good consolidation of the grafts have been observed, this was demonstrated by intense osteogenesis indicating an active remodeling process. In all groups, the improvement in bone quality of the receptor site was clear with no statistical significance between the groups, however, the autografts presented better bone quality.Conclusions: From this study it was possible to conclude that quality of bone repair using autogenous bone graft is superior to bone marrow aspirate. The time needed for bone maturation is less when chin or iliac autogenous grafts have been used in comparison to the bone marrow aspirate.

The Bone Core Technique for the Augmentation of Limited Bony Defects: Five-Year Prospective Study with a New Minimally Invasive Technique.

The aim of this study was to evaluate a new minimally invasive surgical technique for the reconstruction of critical-size bony defect with local harvested bone core with simultaneous implant placement. In a prospective study, 186 consecutively treated patients were included and controlled clinically and radiologically for at least 5 years postoperative. Every patient presented a bony defect affecting the buccal, lingual, or palatal wall. In all cases, the alveolar crest was wide enough to allow implant placement inside the bony contours. During implant bed preparation, a trephine bur (3.5 mm external diameter and 2.5 mm internal diameter) was used to harvest a bone core from the socket. After implant insertion, the buccal/palatal/lingual bony defect was grafted with bone chips covered with the bone core stabilized through compression with microscrews. After 3 months of healing, the implants and the grafted bone were exposed and the width of the grafted area was measured. After prosthetic restoration, the patients were recalled regularly. A total of 223 grafted sites were documented. Minor primary healing complications were observed in 3 sites (1.4%), all in smoker patients, and were treated locally without any influence on the prognosis. All other sites healed uneventfully. In 19 cases (4.4%), exposure of the screw heads was detected 1 to 3 months postoperatively without any inflammation or consequences for the grafted bone. The average width of the reconstructed area at the end of the grafting procedure was 2.4 ± 0.8 mm, and at the reentry, 2.1 ± 0.6 mm. There was a difference of remodeling between bone cores grafted totally inside or partially outside the bony contours. Bone cores grafted completely inside the bony contours demonstrated no resorption at 3 months postoperative, while bone cores grafted partially outside the bony contours in most cases showed partial resorption of the bone outside the bony contours. After 3 months of healing, all 223 implants had achieved primary healing and osseointegration and were restored after an average time of 4 months. No implant failed during the control period. According to this study, the use of an autogenous bone core harvested during the implant bed preparation is a simple and safe method for the reconstruction of small bone defects.

Rabbit Calvarial Defect Model for Customized 3D-Printed Bone Grafts.

Bone graft materials are commonly used to regenerate various bone defects, but their application is often limited because of the complex defect shape in various clinical conditions. Hence, customized bone grafts using three-dimensional (3D) printing techniques have been developed. However, conventional simple bone defect models are limited for evaluating the benefits and manufacturing accuracy of 3D-printed customized bone grafts. Thus, the aim of the present study was to develop a complex-shaped bone defect model. We designed an 8-shaped bony defect that consists of two simple circles attached to the rabbit calvarium. To determine the critical-sized defect (CSD) of the 8-shaped defects, 5.6- and 7-mm-diameter trephine burs were tested, and the 7-mm-diameter bur could successfully create a CSD, which was easily reproducible on the rabbit calvarium. The rate of new bone formation was 28.65% ± 8.63% at 16 weeks following creation of the defect. To confirm its efficacy for clinical use, the 8-shaped defect was created on a rabbit calvarium and 3D computed tomography (CT) was performed. A stereolithography file was produced using the CT data, and a 3D-printed polycaprolactone graft was fabricated. Using our 8-shaped defect model, we were able to modify the tolerances of the bone graft and calvarial defect to fabricate a more precise bone graft. Customized characteristics of the bone graft were then used to improve the accuracy of the bone graft. In addition, we confirmed the fitting ability of the 3D-printed graft during implantation of the graft. Our 8-shaped defect model on the rabbit calvarium using a 7.0-mm trephine bur may be a useful CSD model for evaluating 3D-printed graft materials.

Targeted Endodontic Microsurgery: A Novel Approach to Anatomically Challenging Scenarios Using 3-dimensional–printed Guides and Trephine Burs—A Report of 3 Cases

Endodontic microsurgery (EMS) techniques have increased success rates over traditional approaches. Despite surgical advances, anatomically challenging scenarios can preclude EMS in certain cases. The aim of this article was to introduce targeted EMS, which uses 3-dimensional–printed surgical guides (3DSGs) and trephine burs to achieve single-step osteotomy, root-end resection, and biopsy in complex cases. In each of 3 cases, a 3DSG with a trephine port was printed using computer-aided design/computer-aided manufacturing implant planning software. The osteotomy site, angulation, and depth of preparation were defined preoperatively to avoid sensitive anatomic structures. The 3DSG was inserted at the target site to achieve precise osteotomy and root-end resection during surgery. A hollow trephine rotated within the 3DSG port produced single-step osteotomy, root-end resection, and biopsy. Root-end preparation and fill were accomplished, and tissues were sutured in place. Targeted EMS potentiated successful surgical treatment in 3 anatomically challenging scenarios: (1) a palatal approach to the palatal root of a maxillary second molar, (2) a facial approach to a fused distofacial-palatal root of a maxillary first molar, and (3) a mandibular second premolar in close proximity to the mental foramen. Trephine burs guided by 3DSGs produce efficient targeted osteotomies with a predictable site, angulation, and depth of preparation. Apical surgery in challenging anatomic cases such as the palatal root of the maxillary second molar, fused molar roots, and root ends in approximation to the mental nerve are possible with targeted EMS.

Histo-morphologic characteristics of intra-osseous implants of WE43 Mg alloys with and without heat treatment in an in vivo cranial bone sheep model

WE43 Mg alloy, composed of Mg, Yttrium, Rare Earth elements, and Zirconium, has proved to be a suitable candidate for production of resorbable osteosynthesis implants in both clinical and experimental settings. In a previous study we tested biocompatibility and degradation properties of untreated (as-cast) and artificially aged (T-5) WE43 Mg-alloys as subperiosteal implants on a maxillofacial sheep model. Both the alloy compositions showed excellent biocompatibility, however, with respect to degradation rate, the as-cast form showed increased degradability compared with the T-5. In the present study, we tested the same alloy composition (i.e. as-cast and T-5) to assess their biological behavior and degradation pattern when implanted as endosteal implants on a calvarial bone sheep model. Six implants in form of cylindrical discs were tested in 6 sheep, one per composition of each disc was placed in two monocortical cranial defect created with high speed trephine bur in the parietal bone. After euthanasia at 6 weeks histomorphological analysis of the bone/implant specimens was performed. WE43-as cast showed higher degradation rate, increased bone remodeling, gas pockets formation and osteolysis compared with the T5 alloy. WE43-T5 showed greater bone/implant interface stability, and seemed to be more suitable for fabrication of endosteal bone screws.

Crestal Sinus Floor Elevation with Autogenous Press-Fit Dowel Bone Harvested Using Trephine Drills: A New Method.

The aim of this study was clinical and radiographic evaluation of sinus floor lifting from the alveolar crest with trephine bur and autogenous bone graft. In this research, a press-fit dowel bone technique with application of an autogenous bone block was used for elevating the sinus floor. Ten closed sinus lift surgeries were performed on 10 patients; all patients possessed atrophic ridges in an edentulous maxilla. Bone height of the ridge ranged between 3 and 5 mm. Surgery included forming a bony cylinder with a trephine bur to reach the sinus cortical floor and then elevating the sinus floor bone with anosteotom and placing an autogenous bone block at the site and fitting it with strikes of a hand mallet. The amount of an osteotom sinus floor height gain was measured during implant placement and via radiography before surgery and four months postsurgery. Average height of the sinus floor bone after surgery was 8.33 mm with SD = 1.39 mm. Mean bone height gain after surgery in evaluated patients was 3.47 mm with SD = 1.4 mm. As a result, bone sinus floor height following surgery was significantly increased (P value = 0.044), with a significant difference between sinus floor bone height before and after surgery (P value = 0.041). No significant difference was observed between sinus floor bone height gain and sex, age, and smoking before and after the operation. The sinus floor lift method by trephine and autogenous bone graft is a practical and simple way to reduce the time needed for implantation in patients with moderate atrophy of the posterior maxilla.

Effect of herbal extracts on bone regeneration in a rat calvaria defect model and screening system.

ObjectivesThe aim of this study was to evaluate the effects of herbal extracts on bone regeneration. Two known samples were screened.Materials and MethodsWe previously established a rat calvaria defect model using a combination of collagen scaffold and herbal extracts. An 8 mm diameter trephine bur with a low-speed dental hand piece was used to create a circular calvaria defect. The experimental group was divided into 4 classifications: control, collagen matrix, Danshen with collagen, and Ge Gan with collagen. Animals in each group were sacrificed at 4, 6, 8, and 10 weeks after surgery, and bone regeneration ability was evaluated by histological examination.ResultsResults revealed that both Danshen and Ge Gan extracts increased bone formation activity when used with collagen matrix. All groups showed almost the same histological findings until 6 weeks. However, after 6 weeks, bone formation activity proceeded differently in each group. In the experimental groups, new bone formation activity was found continuously up to 10 weeks. In the Danshen and Ge Gan groups, grafted materials were still present until 10 weeks after treatment, as evidenced by foreign body reactions showing multinucleated giant cells in chronic inflammatory vascular connective tissue.ConclusionHistological analyses showed that Danshen and Ge Gan extractions increased bone formation activity when used in conjunction with collagen matrix.

Evaluation of bone healing using rhBMP-2 soaked hydroxyapatite in ridge augmentation: a prospective observational study

BackgroundThe goal of this study is to evaluate complication and effectiveness of alveolar ridge augmentations using a hydroxyapatite-based alloplastic bony substitute with rhBMP-2.MethodsA total of 10 patients (4 males, 6 females; 58.5 ± 8.6 years) participated in this clinical research. Alveolar ridge augmentations were performed in edentulous (4 maxillary posterior, 5 mandibular posterior, and 1 mandibular anterior) regions. Anorganic bovine bone (ABB; Bio-Oss®, Geistlich Pharma AG, Wolhusen, Switzerland) was used as the bone graft material in the control group (n = 5)) while hydroxyapatite-based alloplastic bony substitute with rhBMP-2(HA+rhBMP-2; NOVOSIS®-Dent, CGBio Inc., Seongnam, Korea) was used in the experimental group (n = 5). In order to evaluate relative changes in bone volume and resorption rate of the bone graft material, CBCT radiographs were taken immediately and at 4 months after the bone graft in all subjects. Among the 10 patients, 8 received dental implants in Seoul National University Bundang Hospital, while the others received in local clinics. Bone specimens for further histomorphometric examinations were gained from these 8 patients using trephine burs during the implant placements. Clinical, radiographic, and histomorphometric evaluations were focused because of the small sample size.ResultsWhen CBCT radiographs were compared between immediately and at 4.07 ± 0.13 months after the bone graft, both alveolar bone widths (ABB 2.52 ± 0.18 mm, HA+rhBMP-2 1.75 ± 0.85 mm) and heights (ABB 1.68 ± 0.17 mm, HA+rhBMP-2 1.57 ± 0.28 mm) increased in the two groups. Resorption rates of transplanted bone graft material in the alveolar bone widths and heights were (ABB 29.7 ± 8.8%, HA+rhBMP-2 31.5 ± 7.4%) and (ABB 39.2 ± 21.8%, HA+rhBMP-2 52.6 ± 6.5%), respectively. Histomorphometrically, ABB group showed bone formation via osteoconduction and HA+rhBMP-2 group via osteoinduction. HA+rhBMP-2 group showed more bone formation around the bone graft materials than the ABB group. Postoperative complications were not found in all subjects.ConclusionsOur study had following conclusions: (1) Ridge augmentations using HA+rhBMP-2 could be clinically useful to supplement implant placements in edentulous regions. (2) Serious postoperative complications related to the graft material did not occur.

Abstract: Implantable Deferoxamine Facilitates Non-Vascularized Grafting in Irradiated Bone

INTRODUCTION: The goal of this proposal is to therapeutically reverse the damaging effects of radiotherapy on bone formation and healing to enable non-vascularized grafting in irradiated bone. Utilizing a rodent model of mandibular bone grafting, we quantified metrics of diminished graft take and bone healing in response to radiation treatment. Subsequently, we utilized implantable deferoxamine (DFO)-an angiogenic stimulant, to reverse these radiation-induced detriments. We hypothesized that the addition of our proposed therapy, would evidence quantifiable degrees of remediation on the process of tissue regeneration, graft incorporation and bone healing. METHODS: Male Lewis rats received a human equivalent dose of radiotherapy (7Gy/d x 5d) to left hemi-mandibles. After recovery, a circular trephine burr (6mm) was utilized to create a critical size defect just posterior to the third molar, and a bone graft was harvested from the right hemi-mandible of the same animal and secured with a custom PLA resorbable plate. Three groups (n=8/group) of animals were investigated: Control, (irradiated) XRT and irradiated + implantable deferoxamine (DFO). Mandibles were imaged at 14, 40 and 60 days with in vivo µCT, and a 60-day healing period was allowed prior to further outcomes testing. Bony union was judged clinically by 3 blinded reviewers on a scale from 0 to 4, representing the approximate percentage of robust union formation along the circular graft-recipient site interface (e.g. 1=25%, 4=100%). Statistical comparisons were conducted with ANOVA (p<0.05). RESULTS: We observed a significant diminution of bone graft healing after radiotherapy. At 60 days, the bone volume fraction (BVF) of the XRT group decreased by 20% (p=0.001), and exhibited lower bony union scores when compared to control (p=0.005). With the addition of DFO, these findings were largely remediated. At 60 days, the BVF improved upon the XRT BVF by 12% (p=0.025), and was not different than control (p=0.282). In addition, the bony union scores of the implanted DFO group significantly improved from XRT levels (p=0.05), and were not different than control (p=0.200). CONCLUSION: Implantable DFO strongly remediates the effects of radiation on non-vascularized bone graft incorporation and healing as measured by micro-densitometry and bony union analysis. These observations are promising with regards to the potential utility of this therapy to enhance bone graft incorporation in the irradiated mandible for head and neck cancer survivors.

Bone core and implant retrieval tool – a review of three trephine bur systems

AbstractAimTo assess and compare the difficulty and structural integrity of bone core harvesting and retrieval prior to implant placement using three different trephine bur systems.MethodsBone core samples were harvested from patients scheduled to receive maxillary dental implants following iliac crest bone graft augmentation. Three trephine bur systems were used and comparison was based on the retrieval time, sample integrity, and implant stability.ResultsDifferences existed between the systems in terms of difficulty and the retrieved bone cores. The formerly planned implant size could be placed in all cases. More structurally intact cores could be achieved although this came at the expense of reliability.ConclusionsThe Easy Retrieve trephine bur system might be recommended in situations where bone sample structural integrity is paramount. Nevertheless, the potential reliability issue with the smaller bur in this system should be taken into consideration.

Newly Formed Bone Induced by Recombinant Human Bone Morphogenetic Protein-2: A Histological Observation.

To observe, histologically, bone induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) in onlay grafted and sinus lifted alveolaris. Eighteen patients were treated with rhBMP-2 at concentration 1.5 mg/mL with an absorbable collagen sponge (ACS). The treated bone was harvested with small trephine bur at 5 or 7 months after surgery for the micro Computer Scanning (CT) and light microscopic observation. Micro CT showed clearly 3-dimensional trabecular bone structure. New bone formation and bone marrow structure were observed in the observed area. Osteoblastic cells existed along the new bone, and osteopontin was localized in the bone matrix weakly. In the connective tissue around the new bone, many CD34-positive blood vessel cells were present. Some tartrate-resistant acid phosphatase (TRAP)-positive osteoclastic cells were observed around bone at this stage. The application of rhBMP-2 with ACS induced a new bone accompanied by blood vessels in atrophied alveolaris. This suggests that rhBMP-2 is capable of osteoinductivity in human jaw.

Bone Healing Evaluation in Critical-Size Defects Treated With Xenogenous Bone Plus Porcine Collagen

This study aimed to evaluate the osteoconductive features of Bio-Oss Collagen in large critical-size defects (8 mm). Thirty-six adult Wistar Albinus male adult rats were carried out a critical-size defect with a trephine bur of 8 mm in the calvaria. Groups were divided depending on the filling biomaterial as follows: group BO: Bio-Oss (n = 18); group BOC: Bio-Oss Collagen (n = 18). After 7, 30, and 60 days, 6 rats of each group were euthanized with anesthetic overdose. Specimens were laboratory processed for histomorphometric analysis. Histomorphometric data were statistically analyzed by analysis of variance and post-Tukey test (P < 0.05). Statistical differences were found in new bone formation just in the intragroup comparison among periods after 7 and 60 postoperative days, indicating more new bone formation after 60 days (Tukey test, P = 0.029). Under the limitation of this research, it could be concluded that Bio-Oss and Bio-Oss Collagen in this experimental model did not show osteoconductive features.