Margin Of Defect Research Articles

The role of simvastatin in the osteogenesis of injectable tissue-engineered bone based on human adipose-derived stromal cells and platelet-rich plasma

An injectable tissue-engineered bone (ITB) composed of human adipose-derived stromal cells (hADSCs) and platelet-rich plasma (hPRP) was preliminarily constructed, but its osteogenic capability needs improving. This study aimed to evaluate if simvastatin can be applied as a bone anabolic agent for this ITB. We found 0.01 μ m, 0.1 μ m, and 1 μ m simvastatin could induce hADSCs’ osteoblastic differentiation in vitro that accompanied with non-inhibition on cell proliferation, high alkaline phosphatase activity, more mineralization deposition and more expression of osteoblast-related genes such as osteocalcin, core binding factor α1, bone morphogenetic protein-2, vascular endothelial growth factor, and basic fibroblast growth factor. Simvastatin at 1 μ m seemed the most optimal concentration due to its high osteocalcin secretion in media ( P < 0.01). Quantitative mineralization assay also showed 1 μ m SIM had the most obvious synergistic effect on hPRP’s induction for matrix mineralization of hADSCs ( P < 0.01). When 1 μ m Simvastatin was applied to this ITB to restore the critical-sized calvarial defects in mice, more bone formation was observed in defected regions, and the peripheries just outside the defect margins by X-ray analysis, and H&E staining. These findings indicate that simvastatin at optimal concentrations can be used to promote this ITB’s osteogenesis. However, simvastatin’s effects on this ITB await long-term investigation.

Spontaneous healing capacity of rabbit cranial defects of various sizes

PurposeThis study evaluated the spontaneous healing capacity of surgically produced cranial defects in rabbits with different healing periods in order to determine the critical size defect (CSD) of the rabbit cranium.MethodsThirty-two New Zealand white rabbits were used in this study. Defects of three sizes (6, 8, and 11 mm) were created in each of 16 randomly selected rabbits, and 15-mm defects were created individually in another 16 rabbits. The defects were analyzed using radiography, histologic analysis, and histometric analysis after the animal was sacrificed at 2, 4, 8, or 12 weeks postoperatively. Four samples were analyzed for each size of defect and each healing period.ResultsThe radiographic findings indicated that defect filling gradually increased over time and that smaller defects were covered with a greater amount of radiopaque substance. Bony islands were observed at 8 weeks at the center of the defect in both histologic sections and radiographs. Histometrical values show that it was impossible to determine the precise CSD of the rabbit cranium. However, the innate healing capacity that originates from the defect margin was found to be constant regardless of the defect size.ConclusionsThe results obtained for the spontaneous healing capacity of rabbit cranial defects over time and the underlying factors may provide useful guidelines for the development of a rabbit cranial model for in vivo investigations of new bone materials.

Linear mucosal defects: a characteristic endoscopic finding of lansoprazole-associated collagenous colitis

copathologic entity characterized by chronic watery diarrhea and, histologically, by the subepithelial deposition of collagen [1,2]. Some luminal antigens, including nonsteroidal anti-inflammatory drugs (NSAIDs) and proton pump inhibitors (PPIs), particularly lansoprazole, are thought to contribute to the development of collagenous colitis. On endoscopy, collagenous colitis usually shows no orminimal nonspecific abnormalities. However, a recent report showed that “linearmucosal defects”, including mucosal tears and sharp longitudinal ulcers, are characteristic colonoscopic findings of lansoprazoleassociated collagenous colitis [3]. We report a case of lansoprazole-associated collagenous colitis that showedmultiple linearmucosal defects in the colon. A 67-year-old womanwas referred to our hospital with a 1-month history of continuous watery diarrhea and abdominal pain. The patient had been taking 15mg of lansoprazole daily for the past 4 months for gastroesophageal reflux disease. She had no previous history of other gastrointestinal disease. The left lower abdomen was painful on palpation. A stool culture was negative for any enteric pathogens. Colonoscopy revealed a linear mucosal defect surrounded by edematous mucosa in the descending colon (l Fig. 1) and the proximal sigmoid colon (l Fig. 2). In addition, a linear and scarred mucosal defect was observed in the distal sigmoid colon (l Fig. 3). The sharply demarcated margin of the mucosal defect differentiated it from ischemic colitis. Multiple biopsy specimens, including those around the mucosal defect, were found to have thickened subepithelial collagen bands and inflammation of the lamina propria (l Fig. 4). This patient’s clinical and histological findings were compatible with the diagnosis of collagenous colitis. After discontinuation of lansoprazole treatment, the patient’s symptoms improved. Although the endoscopic finding in collagenous colitis is generally considered to be normal or near-normal mucosa, observation of a linear mucosal defect is useful for diagnosis of lansoprazole-associated collagenous colitis.

F-18 FDG PET/CT Findings in Two Patients With Hepatic Angiomyolipoma With and Without Intratumoral Hemorrhage

Two female patients aged 62 and 74 years underwent F-18 FDG PET/CT for evaluation of a large hepatic tumor. Subsequently, both patients underwent a partial hepatectomy which histopathologically revealed benign hepatic angiomyolipomas (AMLs). One patient with AML with a massive intratumoral hemorrhage presented with multiple foci demonstrating an increased FDG uptake along the margin of the cold defects that corresponded to low density areas within the tumor on contrast-enhanced CT, whereas the other patient with AML without any hemorrhage presented with a low FDG uptake in the tumor. This report demonstrates that benign hepatic AMLs may demonstrate increased FDG uptake if there is hemorrhage and a related inflammatory response.

A Long-Term Evaluation of Alternative Treatments to Replacement of Resin-based Composite Restorations: Results of a Seven-Year Study

In a seven-year prospective cohort study, the authors assessed the longevity of defective resin-based composite (RBC) restorations that were not treated or were treated by means of repair, sealing, refinishing or total replacement. They also aimed to identify and quantify the main reasons clinicians diagnosed restorations as defective. Thirty-seven patients--19 women and 18 men--who were aged 27 through 78 years (mean = 57 years, standard deviation [SD] = 13 years) and had a total of 88 defective restorations participated in the study. Two of the authors assigned each restoration to one of five treatment groups, depending on the patient's treatment need: repair (n = 25), sealing of defective margins (n = 12), refinishing (n = 19), replacement (n = 16) and no treatment (n = 16). The authors conducted a survival analysis (according to modified U.S. Public Health Service criteria) at baseline and again at six months, one year, two years and seven years after treatment. The authors determined that the main reasons clinicians diagnosed the 88 restorations as being defective were marginal discoloration (n = 53, 60.2 percent), marginal degradation (n = 18, 20.5 percent) and color mismatch (n = 17, 19.3 percent). The authors examined 69 (78 percent) restorations at six months, 68 (77 percent) after one year, 62 (70 percent) after two years and 53 after seven years (60 percent). The percentages of failed restorations for each treatment after seven years were 0 percent for repair, 0 percent for sealing of defective margins, 18 percent for refinishing, 21 percent for replacement and 23 percent for no treatment. The P value for the log-rank test of equality for these groups was .36. Restorations degraded to varying degrees in all criteria, and the survival of restorations differed among treatment approaches. Longitudinal data collected across seven years support the viability of all nonreplacement restoration treatment strategies.

A Left Ventricular–to–Right Atrial Shunt in a Patient With a Perimembranous Ventricular Septal Defect: Role of Intraoperative Transesophageal Echocardiography

ADHESION OF TRICUSPID valve leaflets around margins of a perimembranous ventricular septal defect (VSD) gives rise to aneurysmal transformation of the membranous septum, which partially or completely occludes blood flow through the VSD. A case of a perimembranous VSD with a left ventricular–to–right atrial (LV-to-RA) shunt, which was misinterpreted as a tricuspid regurgitation (TR) jet on preoperative transthoracic echocardiography (TTE), is reported. Correct diagnosis was made by intraoperative transesophageal echocardiography (TEE).

How dentists diagnose and treat defective restorations: evidence from the dental practice-based research network.

To (1) identify and quantify the types of treatment that dentists use to manage defective dental restorations and (2) identify characteristics that are associated with these dentists' decisions to replace existing restorations. The Dental Practice-Based Research Network (DPBRN) consists of dentists in outpatient practices from five regions: AL/MS: Alabama/Mississippi; FL/GA: Florida/Georgia; MN: dentists employed by HealthPartners and private practitioners in Minnesota; PDA: Permanente Dental Associates in cooperation with Kaiser Permanente's Center for Health Research and SK: Denmark, Norway and Sweden. A questionnaire was sent to all DPBRN practitioner-investigators who reported doing some restorative dentistry (n = 901). Questions included clinical case scenarios that used text and clinical photographs of defective restorations. Dentists were asked what type of treatment, if any, they would use in each scenario. Treatment options ranged from no treatment to full replacement of the restoration with or without different preventive treatment options. The authors of the current study used logistic regression to analyze associations between the decision to intervene surgically (repair or replace) and the specific dentist, practice and patient characteristics. A total of 65% of dentists would replace a composite restoration when the defective margin was located on dentin and 49% would repair it when the defective margin was located on enamel. Most (52%) dentists would not intervene surgically when the restoration in the scenario was amalgam. Dentists participating in a solo or small private practice (SPP) chose surgical intervention more often than dentists participating in large group practices (LGP) or in public health practices (PHP) (p < .0001). Dentists who do not routinely assess caries risk during treatment planning were more likely to intervene surgically and less likely to choose prevention treatment (p < .05). Dentists from the SK region chose the "no treatment" option more often than dentists in the other regions. Dentists were more likely to intervene surgically when the restoration was an existing composite, compared to an amalgam restoration. Treatment options chosen by dentists varied significantly by specific clinical case scenario, whether the dentist routinely performs caries risk assessment, type of practice and DPBRN region.

Combination of bone tissue engineering and BMP‐2 gene transfection promotes bone healing in osteoporotic rats

The aim of this study was to develop a feasible approach to promote bone healing in osteoporotic rats using autogenous bone tissue-engineering and gene transfection of human bone morphogenetic protein 2 (hBMP-2). Bone marrow stromal cells (BMSCs) from the left tibia of osteoporotic rats were transfected with the hBMP-2 gene in vitro which was confirmed by immunohistochemistry, in situ hybridization and Western blotting. Autogenous transfected or untransfected BMSCs were seeded on macroporous coral hydroxyapatite (CHA) scaffolds. Each cell-scaffold construct was implanted into a defect site which was created in the ramus of the mandible of osteoporotic rats. Four or eight weeks after implantation in situ hybridization was performed in BMSCs transfected with hBMP-2, X-ray examinations, histological and histomorphological analyses were used to evaluate the effect of tissue-engineered bone on osseous defect repair. Newly formed bone was observed at the margin of the defect 4 weeks after implantation with BMSCs transfected with BMP-2. Mature bone was observed 8 weeks after treatment. In the control group there was considerably less new bone and some adipose tissue was observed at the defect margins 8 weeks after implantation. Autogenous cells transfected with hBMP-2 promote bone formation in osteoporotic rats. BMSC-mediated BMP-2 gene therapy used in conjunction with bone tissue engineering may be used to successfully treat bone defects in osteoporotic rats. This method provides a powerful tool for bone regeneration and other tissue engineering.

Combinatorial Gene Therapy with BMP2/7 Enhances Cranial Bone Regeneration

BMP2/7 heterodimer expression by adenovirus can stimulate bone formation at subcutaneous sites. In the present study, we evaluate whether this approach will also promote healing of cranial defects. Adenovirus expressing BMP2 or BMP7 (AdBMP2, AdBMP7) was titrated to yield equivalent BMP protein levels after transduction into murine BLK cells. Analysis of conditioned medium showed that BMP2/7 heterodimers have enhanced ability to stimulate alkaline phosphatase and Smad 1,5,8 phosphorylation relative to equivalent amounts of BMP2 or BMP7 homodimers. To measure bone regeneration, we implanted virally transduced BLK cells into critical-sized calvarial defects generated in C57BL6 mice. AdBMP2/7-transduced cells were more effective in healing cranial defects than were cells individually transduced with AdBMP2 or BMP7. Dramatic increases in bone volume fraction, as measured by microCT, as well as fusion of regenerated bone with the defect margins were noted. Thus, the use of gene therapy to express heterodimeric BMPs is a promising potential therapy for healing craniofacial bones.

Acceleration of de novo bone formation with a novel bioabsorbable film: a histomorphometric study in vivo

Different types of barrier membranes have been used in periodontal applications for the technology of guided tissue regeneration (GTR). The aim of this study was to characterize the biological effect of novel calcium alginate film (CAF) on bone tissue regeneration by using rabbit mandible defects model. A critical size defect (5 mm in diameter) was created in the bilateral corner of mandible of 45 adult rabbits. The defects were covered with CAF served as the experimental group, or conventional collagen membrane (CCM) or left empty as the controls. Animals were killed after 1, 2, 4, 6 and 8 weeks. Morphological and histomorphometric studies were performed to evaluate their bone regeneration pattern and biological effects. Histological sections showed that bone regeneration pattern was centripetal in growth from defect rim. The quantitative histometry analysis revealed a significantly greater percentage of newly generated bone in CAF defects than that in CCM defects and empty defects from 2 to 6 weeks post-operation (P < 0.01). After 6 and 8 weeks, significantly more mature lamella bone had formed with CAF than with CCM. Empty control defects showed bone formation starting from the defect margins and incomplete healing even after 8 weeks. The CAF guided early bone growth and appeared more effective as a bioabsorbable GTR membrane than CCM. This study with mandible defect model suggests that bone defects augmented with CAF may offer most promising results from a histological and histomorphometric perspective.

Millikan KW, Doolas A (2007) A long-term evaluation of the modified mesh-plug hernioplasty in over 2,000 patients

Dear Professor Schumpelick, We were glad to see that the results of this complete and thorough prospective audit are those that any general surgeon can attain. We too have had similar gratifying results with simple modiWcations of the original description of the “plug and patch” inguinal hernioplasty [1]. The important issue is that the dissection is “high” into the preperitoneal space, which is easily identiWed as having been reached by the glistening bright yellow preperitoneal fat, something that is rarely made enough fuss of. Indeed, we have often thought that the “PERFIX plug” would have been better named the “PREFIX plug” to remind surgeons that correct placement is the crucial step in this technique of repair. Furthermore, to attain a good preperitoneal placement of the plug, its outer petals are best stretched and Xattened, as illustrated in Fig. 1. Only then are the inner petals sutured to the margins of the hernial defect. This simple modiWcation allows the outer layer of the plug to sit astride the defect in the perperitoneal plane as a “sublay” patch. Since 1997, we have used this repair in 1,255 patients with very satisfying results and a paucity of complications in both the short and long term. We have had three cases of urinary retention and nine haematomas, of which, four needed draining. In the original description [1], it was suggested that the mesh patch was placed without sutures, as it was only there to augment the beneWt of the “plug.” Although we believe this still to be true, we now anchor the patch medially with one stitch just short of the pubic tubercle. This simple single suture keeps the patch in close proximity to the back wall of the canal. With these simple modiWcations, we have not seen a case of migration or sepsis, and have had to excise only one plug (in a butcher) at a median follow up of 7 years. Our recurrence rates are similar to that of these authors, but they do vary as to the aetiology of the hernial defect; primary indirect 2/789 (0.25%), primary direct 3/360 (0.83%) and 1/87 (1.1%) when a plug repair is used to manage a recurrence following a previously sutured repair. As stated some time ago, the “plug and patch approach” has caught on [2, 3], but its simplicity should not be an excuse for a poor anatomical dissection. At this point, it would be prudent to recall the words of Wakely, quoted by Glassow, well before the widespread use of mesh, who said “a surgeon can do more for his community by operating on hernia cases and seeing that his results are good, than by operating on cases of malignant disease” [4, 5]. In other words, if we do it well, we can all get good results and, with this technique, the anatomy is familiar to us all and the learning curve short.

Effect of protein transduction domain fused-bone morphogenetic protein-2 on bone regeneration in rat calvarial defects

Purpose: Recombining bone morphogenetic protein (BMP) is usually acquiredfrom high level animals. Though this method is effective, its high cost limits its use. The purpose of this study was to evaluate the effect of bone morphogenetic protein-2 with protein transduction domain (BMP-2/PTD;TATBMP-2) on bone regeneration. Rat calvarial defect model and osteoblastic differentiation model using MC3T3 cell were used for the purpose of the study. Materials and Methods: MC3T3 cells were cultured until they reached a confluence stage. The cells were treated with 0, 0.1, 1, 10, 100, 500 ng/ml of BMP-2/PTD for 21 days and at the end of the treatment, osteoblastic differentiation was evaluated usingvon Kossa staining. An 8mm, calvarial, critical-size osteotomy defect was created in each of 48 male Spraque-Dawley rats (weight 250~300 g). Three groups of 16 animals each received either BMP-2/PTD (0.05mg/ml) in a collagen carrier, collagen only, or negative surgical control. And each group was divided into 2 and 8 weeks healing intervals. The groups were evaluated by histologic analysis(8 animals/group/healing intervals) Result: In osteoblastic differentiation evaluation test, a stimulatory effect of BMP-2/PTD was observed in 10ng/ml of BMP-2/PTD with no observation of dose-dependent manner. The BMP-2/PTD group showed enhanced local bone formation in the rat calvarial defect at 2 weeks. New bone was observed at the defect margin and central area ofthe defect. However, new bone formation was observed only in 50% of animals used for 2weeks. In addition, there was no new bone formation observed at 8 weeks. Conclusion: The results of the present study indicated that BMP-2/PTD(TATBMP-2) have an positive effect on the bone formation in vitro and in vivo. However, further study should be conducted for the reproducibility of the outcomes. (J Korean Acad Periodontol 2008;38:153-162)

An approach to managing non-melanoma skin cancer of the nose with mucosal invasion: our experience

Conclusions. The absence of recurrences after final nasal reconstruction demonstrates the reliability of our three-stage strategy and the necessity to delay nasal reconstruction, focusing attention on oncological safety for nasal non-melanoma skin cancer (NMSC) with mucosal invasion. Objectives. To validate a therapeutic strategy aimed at oncological safety and minimization of possible recurrences after full-thickness excision of nasal NMSC with mucosal invasion. The strategy was divided into three stages: surgical excision with clinically safe perilesional skin margins and extemporary frozen section histological control; 8–15 months follow-up leaving the nasal defect unreconstructed with a ‘wait and see’ strategy; new extemporary histological control of defect margins and, if negative, definitive reconstruction. Patients and methods. Twenty patients affected by nasal NMSC with mucosal invasion were treated and followed up. Results. Basal cell carcinoma was the most common lesion (75%), followed by squamous cell carcinoma (25%). Ultrasonography excluded lymphatic involvement for SCC. Before final reconstruction, extemporary histological examination revealed the presence of tumour cells in three patients. After tumour extirpation, these patients were resubmitted to a new follow-up period before reconstruction. No recurrences were observed after definitive nasal reconstruction in all patients during the 5-year follow-up.

Effect of low intensity pulsed ultrasound on healing of an ulna defect filled with a bone graft substitute

A 1.5 cm unilateral rabbit ulna defect model was performed in 18 adult NZ white rabbits. The defects were filled with a beta-tricalcium phosphate bone graft substitute (JAX TCP). The surgical site in half the animals was treated daily with 20 min of low intensity pulsed ultrasound (LIPUS). Animals were sacrificed at 4 weeks (n = 3 per group) or 12 weeks (n = 6 per group) following surgery for radiographic and histologic endpoints. Radiography revealed some resorption of the JAX TCP by 12 weeks in the control and LIPUS treated groups. LIPUS treatment did not accelerate this resorption. Some new bone formation was noted in the control groups at the defect margins while little bone formed in the center of the defect at 4 and 12 weeks. In contrast, radiographs revealed more new bone at 4 and 12 weeks in the LIPUS treated animals throughout the section. Bone mineral density (DEXA) revealed a statistically significant difference at 4 weeks with LIPUS while no differences were found at 12 weeks. Histology of the LIPUS treated sections demonstrated new woven bone formation on and between the JAX TCP bone graft substitute particles across the defect. VEGF expression was increased with LIPUS treatment at 4 weeks and remained elevated at 12 weeks compared with controls. CBFA-1 expression levels were elevated with LIPUS treatment at both time points. LIPUS treatment increased bone formation in ulna defect healing with a beta-tricalcium phosphate bone graft substitute.

A Review of Two Animal Studies Dealing with Biological Responses to Glass-Fibre-Reinforced Composite Implants in Critical Size Calvarial Bone Defects in Rabbits

In these studies, E-glass-fibre-reinforced composite (FRC) implants with photopolymerisable resin systems and bioactive glass granules (BAG) were evaluated as a reconstructive material in the critical size bone defects made to rabbits’ calvarial bones. In the first study, a new experimental resin system, DD1/MMA/BDDMA, was used to impregnate the doubleveil FRC-implants, while in the second study, a commercial resin system composed of BisGMA/MMA/PMMA was used in impregnation. These double-veil FRC-implants were coated with bioactive glass granules (BAG, 315-500 0m). In the second study, an experimental FRC consisting of two laminates of woven fibres, was also tested as an implant material. These implants were filled with BAG-granules and pure fused quartz fibers (Quartzel wool). In the first study, implantation time was 4 or 12 weeks, while in the second study, it was 12 weeks for both the implant types. Results: In the first study, the healing of the defects had started in the form of new bone growth from the defect margins, as well as small islands of woven bone in the middle of the defect, at 4 weeks postoperatively. Ingrowth of dense connective tissue into the pores of the implant was widely seen. At 12 weeks postoperatively, more bony islands were seen as compared to the animals studied at 4 weeks. Part of the newly formed bone had an appearance of lamellar structure. The porous structures of the implant were deeply filled with fibroconnective tissue. Ingrowth of maturing bone to the implant structures was occasionally seen. The inflammatory reaction was moderate, and was mostly found inside the upper part of the implant. In the second study, inflammatory reactions caused by both types of the FRC implants were very slight. Small amount of new bone had started to grow from the defect margins in doulble-veil implanted defects. No ingrowth of connective tissues or new bone formation was seen inside these implants. Instead, both the connective tissues and newly formed, mineralizing bone were seen inside the experimental double-laminate implants. SiO2-fibres seemed to cause moderate inflammatory reaction inside the implants, while BAG granules did not. In both the study groups, the brain tissue was oedemic, but no obvious serious damage was found. Conclusions: The structural properties of the FRC-implants had an influence on the healing process of the bone defect. BAG, as a constituent of the FRCimplants, enhanced the bone formation process. After some modifications to the properties of the FRC, this type of implant has possibilities to become one material alternative in clinical bone defect reconstruction at the craniofacial area in the future.

Effect of Synthetic β-TCP and Bovine-Derived Hydroxyapatite Grafting on Bone Regeneration in Rats

We evaluated the bone healing effect of grafting with synthetic β-tricalcium phosphate (β-TCP; Cerasorb®), bovine-derived hydroxyapatite (HA; Bio-Oss®), and a mixture of β-TCP and HA in rats. Each material was grafted in prepared 8-mm frontal bone defects in 15 rats. The control group underwent surgery without any grafting materials and was examined after 4 weeks, whereas the experimental groups received grafting materials and were examined after 1, 2, and 4 weeks. After implantation, the rats were sacrificed for histomorphometric studies using light microscopy, and the data were analyzed using analysis of variance. Considerable inflammation and fibrosis were observed after 1 and 2 weeks in all experimental groups, whereas the inflammation was reduced and fibrosis was stabilized after 4 weeks. New bone formation was observed at the defect margin. Statistically, there was no difference in new bone formation among the three experimental groups. In conclusion, there was no difference in new bone formation using Bio-Oss®, Cerasorb®, and a mixture of Bio-Oss® and Cerasorb®.

Polycaprolactone-20% Tricalcium Phosphate Scaffolds in Combination With Platelet-Rich Plasma for the Treatment of Critical-Sized Defects of the Mandible: A Pilot Study

Our group has recently fabricated 3-dimensional scaffolds of unique architecture to mediate favorable cell binding, proliferation, and differentiation. In this study, the osteoconductive and bioactive polycaprolactone-20% tricalcium phosphate (PCL-TCP) scaffolds were assessed for the treatment of critical-sized defects of the mandible, with respect to new bone formation. Platelet-rich plasma (PRP) was combined with some scaffolds to test if bone regeneration could be enhanced. Autologous PRP was prepared from whole blood collected from 8 mongrel dogs. In each dog, 3 defects (18 x 10 x 7 mm) were created at either the left or right mandible and treated with 1 of 2 treatment modalities: 1) grafting with scaffolds alone; or 2) grafting with scaffolds loaded with PRP. The scaffolds were stabilized using 2 dental implants each to prevent rotation. Micro-CT and histologic analysis were carried out on samples after 6 and 9 months. Micro-CT measurements showed that PRP-treated defects had 98.3% and 58.3% more bone volume fraction than defects grafted with scaffolds alone at 6 and 9 months, respectively (P < .05). No significant difference was noted between caudal and frontal situated PRP-treated defects, but a significant difference was observed between male and female dogs. Histologic analyses verified the deposition of osteoid and new bone trabeculae throughout the section at 6 months. The defect margins were filled with mature bone trabeculae at 9 months but the middle section of the scaffolds manifested disturbed mineralization. The scaffolds experienced 33% degradation from 6 to 9 months. PRP treatment had negligible effect on the degradation of the scaffolds. The pilot study showed that the treatment of critical-sized defects of the mandible with PCL-TCP scaffolds may be augmented by the addition of PRP.

Assessing ASDs prior to device closure using 3D echocardiography. Just pretty pictures or a useful clinical tool?

To determine the usefulness of three-dimensional transthoracic echocardiography (3D echo) in assessment of secundum atrial septal defects (ASDs) considered for device closure. To compare the findings from 3D echo with those from two-dimensional transoesophageal echocardiography (TOE) regarding dimensions, morphology and suitability for device closure. Twenty-four patients were enrolled in this prospective, crossover study. Three-dimensional echo and TOE data were collected, analysed and compared, assessing quantitative data including maximum defect diameter, area and circumference. Qualitative morphology such as the presence of fenestrations and the defect margins were noted, and an assessment of the suitability for device closure was made using each modality. Eighteen (75%) of the 3D data sets produced usable data for analysis. In each case the maximum diameter of the defect was larger on 3D echo than on TOE (mean difference = 0.34 cm, P < 0.001). On three occasions suitability for device closure could not be determined using 3D echo. On the other 15 occasions there was agreement between the TOE and 3D echo data. Three-dimensional echo provides comparable data with TOE when attempting to predict suitability for device closure without the need for general anaesthetic or sedation. It also provides useful additional dynamic and morphological information.

Covered Stent Deployment for a Thoracic Aortic Pseudoaneurysm Associated with Pseudocoarctation of the Aorta

An 11-year-old girl presented to our unit after transcatheter occlusion of a patent arterial duct (PDA) with a Rashkind device at 1 year of age. She had been treated for osteomyelitis and also had previously undergone a repeat Nissen fundoplication. She was hypertensive with diminished femoral pulses. Two-dimensional transthoracic echocardiography showed a diastolic tail on spectral Doppler. However, no discrete coarctation of the aorta was observed. Diagnostic cardiac catheterization demonstrated a bilobed saccular protrusion from the descending thoracic aorta (Fig. 1a) with a pullback gradient of 30 mmHg across the defect. Magnetic resonance imaging confirmed a bilobed pseudoaneurysm of the thoracic descending aorta with a smaller upper component and a larger lower component (Fig. 1b). Both methods demonstrated the close relationship of the posterior intercostal arteries to the presumed false aneurysm. Left and right eighth and tenth intercostal arteries arose from a normal aorta very close to the margins of the defect. Left and right ninth intercostal arteries arose from the abnormal aorta, the left ninth from the upper surface of the larger lobe of the aneurysm. The importance of this region lies in the arteria radicularis magna (of Adamkiewicz), which usually arises from a lower intercostal or upper lumbar branch of the aorta. Because the radicular arteries, and particularly this artery, may be the only blood supply to large portions of the spinal cord, the consequent risk of cord infarction must be considered before intervention. In this case, the eighth and tenth posterior intercostal vessels supplied relatively large vessels running into the spinal vasculature. We deployed a 38-mm covered stent (Jomed International, Helsinborg, Sweden) mounted on a 10 mm · 4 cm Powerflex balloon (Cordis Europe, Roden, The Netherlands). Angiography after deployment demonstrated a good result, and although several intercostal vessels were excluded from the aorta (Fig. 1c), there was no spinal cord compromise with normal lower limb neurology. A followup computed tomography (CT) scan demonstrated residual flow into the pseudoaneurysm inferiorly. An overlapping 28-mm covered stent was deployed, resulting in complete resolution of the residual leak (Fig. 2). True and false aneurysms of the descending thoracic aorta are well described in the setting of aortic coarctation after both surgical repair [1, 2] and transcatheter endovascular stenting [3]. The etiology of this lesion remains debatable. Although we favor trauma as a cause during the previous cardiac catheterization, mycotic aneurysm secondary to osteomyelitis or indeed damage during the Nissen fundoplication also may provide alternative explanations. Deployment of covered stents for thoracic aortic aneurysms is well described [4] and may be preferable to surgery with little or no compromise of the spinal vessels reported.

Interaction of Peroxides with Amalgam: A Case Report

Nightguard vital bleaching with 10% carbamide peroxide was shown to have some minor effects on certain brands of amalgam mainly related to mercury release. However, in this case report, amalgam staining of the bleaching tray was detected in correspondence of the left and right first upper molars following tooth whitening for a week. These teeth presented mesio occlusal distal amalgam fillings with superficial chipping at the cavosurface margins. The same phenomena did not occur in the mouth with other amalgam intracoronal restorations not showing marginal defects. No decay or discoloration was noted around the amalgam fillings both in the upper and lower teeth. At the 1-week recall visit, patient was recommended to avoid the bleaching gel application in the maxillary first molar teeth. The existing fillings were replaced with composite resin restorations after a 2-week elapse time. The unusual amalgam staining of the bleaching tray suggests that amalgam restorations with defective cavosurface margins should be monitored during the tooth whitening therapy. Alternatively, their replacement should be considered prior to bleaching.