Micro-CT evaluation of two different root canal filling techniques.

OBJECTIVE: The aim of this study was to compare the frequency and volume of voids in root canals obturated with two different filling techniques using micro-computed tomography (micro-CT). MATERIALS AND METHODS: Forty single-rooted permanent teeth were selected and decoronated. The roots were instrumented with WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) to a large size until working length and irrigated with 5.25% sodium hypochlorite and 17% EDTA. Then, the samples were filled using a single-cone (n = 20) or the GuttaCore technique (n = 20). The presence and volume (mm3) of voids (internal, external, and combined) was calculated in the coronal, medium, and apical thirds using micro-CT (SkyScan 1072; SkyScan, Kartuizersweg, Belgium). Statistical analyses were performed using the χ2-test and Kruskal-Wallis tests (p<0.05). RESULTS: The frequency and total volume of voids in the middle third and the external voids in the coronal third were statistically significant (p<0.05). Within the same group, both techniques (single-cone and Guttacore) showed statistically significant differences in external and internal voids (p<0.05). CONCLUSIONS: The GuttaCore technique showed better results in the coronal and medium thirds than the single-cone technique. Our results showed that the single-cone and GuttaCore techniques were comparable in the apical third (p>0.05).

Bone-anchored hearing implant surgery: our experience with linear incision and punch techniques.

SUMMARY: In recent years, bone-anchored hearing implants (BAHIs) have found wider application in the treatment of conductive and mixed hearing loss. Several surgical techniques have been developed to reduce complications, enhance healing and improve audiological and aesthetic results. We report our experience on the use of three BAHI surgery techniques: Group 1, linear incision with thinning of the subcutaneous tissue; Group 2, linear incision without thinning of the subcutaneous tissue; Group 3, punch technique (Minimally Invasive Ponto Surgery, MIPS). We retrospectively analysed patients undergoing BAHI surgery; results were evaluated on the basis of any intra-operative complication, duration of surgery and occurrence of adverse effects at the implantation site over 1 year of follow-up. We collected a total of 30 implantations (12 for Group 1, 8 for Group 2, 10 for Group 3) with an intra-operative complication rate of 25%, 0% and 10%, respectively. The average surgical time was 62.08 minutes, 34.37 minutes and 18.7 minutes respectively. During follow-up, we reported the occurrence of adverse effects in 10.63% of observations in Group 1, 3.12% in Group 2 and 2.5% in Group 3. This study confirms the low rate of intra and postoperative complications during BAHI surgery and documents the simplicity of execution of the novel MIPS technique, with a significant reduction in surgical time compared to the other two techniques, and positive effects in terms of health care costs.

Multimodal-3D imaging based on µMRI and µCT techniques bridges the gap with histology in visualization of the bone regeneration process.

Bone repair/regeneration is usually investigated through X-ray computed microtomography (µCT) supported by histology of extracted samples, to analyse biomaterial structure and new bone formation processes. Magnetic resonance imaging (µMRI) shows a richer tissue contrast than µCT, despite at lower resolution, and could be combined with µCT in the perspective of conducting non-destructive 3D investigations of bone. A pipeline designed to combine µMRI and µCT images of bone samples is here described and applied on samples of extracted human jawbone core following bone graft. We optimized the coregistration procedure between µCT and µMRI images to avoid bias due to the different resolutions and contrasts. Furthermore, we used an Adaptive Multivariate Clustering, grouping homologous voxels in the coregistered images, to visualize different tissue types within a fused 3D metastructure. The tissue grouping matched the 2D histology applied only on 1 slice, thus extending the histology labelling in 3D. Specifically, in all samples, we could separate and map 2 types of regenerated bone, calcified tissue, soft tissues, and/or fat and marrow space. Remarkably, µMRI and µCT alone were not able to separate the 2 types of regenerated bone. Finally, we computed volumes of each tissue in the 3D metastructures, which might be exploited by quantitative simulation. The 3D metastructure obtained through our pipeline represents a first step to bridge the gap between the quality of information obtained from 2D optical microscopy and the 3D mapping of the bone tissue heterogeneity and could allow researchers and clinicians to non-destructively characterize and follow-up bone regeneration.

A microRNA code for prostate cancer metastasis.

Although the development of bone metastasis is a major detrimental event in prostate cancer, the molecular mechanisms responsible for bone homing and destruction remain largely unknown. Here we show that loss of miR-15 and miR-16 in cooperation with increased miR-21 expression promote prostate cancer spreading and bone lesions. This combination of microRNA endows bone-metastatic potential to prostate cancer cells. Concomitant loss of miR-15/miR-16 and gain of miR-21 aberrantly activate TGF-ß and Hedgehog signaling, that mediate local invasion, distant bone marrow colonization and osteolysis by prostate cancer cells. These findings establish a new molecular circuitry for prostate cancer metastasis that was validated in patients' cohorts. Our data indicate a network of biomarkers and druggable pathways to improve patient treatment.

Epigone migraine vertigo (EMV): a late migraine equivalent.

Migrainous headache is determined by pathogenetic mechanisms that are also able to affect the peripheral and/or central vestibular system, so that vestibular symptoms may substitute and/or present with headache. We are convinced that there can be many different manifestations of vestibular disorders in migrainous patients, representing true different clinical entities due to their different characteristics and temporal relashionship with headache. Based on such considerations, we proposed a classification of vertigo and other vestibular disorders related to migraine, and believe that a particular variant of migraine-related vertigo should be introduced, namely "epigone migraine vertigo" (EMV): this could be a kind of late migraine equivalent, i.e. a kind of vertigo, migrainous in origin, starting late in the lifetime that substitutes, as an equivalent, pre-existing migraine headache. To clarify this particular clinical picture, we report three illustrative clinical cases among 28 patients collected during an observation period of 13 years (November 1991 - November 2004). For all patients, we collected complete personal clinical history. All patients underwent standard neurotological examination, looking for spontaneous-positional, gaze-evoked and caloric induced nystagmus, using an infrared video camera. We also performed a head shaking test (HST) and an head thrust test (HTT). Ocular motility was tested looking at saccades and smooth pursuit. To exclude other significant neurological pathologies, a brain magnetic resonance imaging (MRI) with gadolinium was performed. During the three months after the first visit, patients were invited to keep a diary noting frequency, intensity and duration of vertigo attacks. After that period, we suggested that they use prophylactic treatment with flunarizine (5 mg per day) and/or acetylsalicylic acid (100 mg per day), or propranolol (40 mg twice a day). All patients were again recommended to note in their diary the frequency and intensity of both headache and vertigo while taking prophylactic therapy. Control visits were programmed after 4, 12 and 24 months of therapy. All patients considerably improved symptoms with therapy: 19 subjects (68%) reported complete disappearance of vestibular symptoms, while 9 (32%) considered symptoms very improved. The subjective judgement was corroborated by data from patients diaries. We conclude that EMV is a clinical variant of typical migraine-related vertigo: a migraineassociated vertigo, headache spell independent, following a headache period, during the lifetime of a patient.

STANDING, a four-step bedside algorithm for differential diagnosis of acute vertigo in the Emergency Department.

Vertigo is generally due to a benign disorder, but it is the most common symptom associated with misdiagnosis of stroke. In this pilot study, we preliminarily assessed the diagnostic performance of a structured bedside algorithm to differentiate central from non-central acute vertigo (AV). Adult patients presenting to a single Emergency Department with vertigo were evaluated with STANDING (SponTAneous Nystagmus, Direction, head Impulse test, standiNG) by one of five trained emergency physicians or evaluated ordinarily by the rest of the medical staff (control group). The gold standard was a complete audiologic evaluation by a clinicians who are experts in assessing dizzy patients and neuroimaging. Reliability, sensibility and specificity of STANDING were calculated. Moreover, to evaluate the potential clinical impact of STANDING, neuroimaging and hospitalisation rates were compared with control group. A total of 292 patients were included, and 48 (16.4%) had a diagnosis of central AV. Ninety-eight (33.4%) patients were evaluated with STANDING. The test had good interobserver agreement (k = 0.76), with very high sensitivity (100%, 95%CI 72.3-100%) and specificity (94.3%, 95%CI 90.7-94.3%). Furthermore, hospitalisation and neuroimaging test rates were lower in the STANDING than in the control group (27.6% vs. 50.5% and 31.6% vs. 71.1%, respectively). In conclusion, STANDING seems to be a promising simple structured bedside algorithm that in this preliminary study identified central AV with a very high sensitivity, and was associated with significant reduction of neuroimaging and hospitalisation rates.

Dimensional and microbiological in vitro analysis of a dental implant locking taper connection.

The present study was carried out to compare the differences in contact, height and contact area between the implant-abutment interface and the implant-healing cap interface of an implant system featuring a locking tapered connection by using X-ray micro-tomography. It was also conducted to test in vitro whether the implant-healing cap tapered interface is capable of preventing bacterial leakage from the implant well to the external environment. The images of the samples, acquired by the X-ray micro-tomography, after being processed with a dedicated software, showed a greater contact height (CH) in the implant-abutment sample (3.57 mm) compared to the implant-healing cap sample (2.52 mm). This was also true for the contact area that was equal to 40.63 mm2 in the implant-abutment sample and 25.14 mm2 in the implant-healing cap sample. No bacteria were detected both in the nutrient of the test group and of the negative control after 24 h. An increased contact height and contact area in a tapered connection, between the implant and the abutment, have demonstrated to offer mechanical and biological advantages, in a implant-healing cap tapered connection. The major concern regards the microbiological aspects of this connection. The implant-healing cap tapered connection provides an hermetic barrier to microbial passage in vitro, even though such connection features lower contact height and contact area compared to the implant-abutment connection of the same implant system.

Peripheral arterial disease in patients with chronic obstructive pulmonary disease.

AIM: Cardiovascular disease (CV) is the second leading cause of morbidity and mortality in chronic obstructive pulmonary disease (COPD). Peripheral arterial disease (PAD) is associated with cardiovascular disease, and its risk factors are common to other atherosclerotic diseases. The objective is to determine the prevalence of PAD in a population of patients with COPD using the ankle / brachial index (ABI) and to investigate the relationship between PAD and lung disease severity. METHODS: In a prospective cross-sectional study, 246 patients with COPD were recruited. Patients were enrolled consecutively according to their admission to Povisa hospital from September 1, 2008, until March 1, 2010, and were assessed by clinical history, spirometry and ABI. The COPD severity was graded by GOLD criteria in spirometry. RESULTS: Overall, 84 patients (36.8%) had abnormal ABI results and 59 (70.2%) were asymptomatic for PAD. COPD patients with PAD had a higher prevalence of moderate to severe COPD (61.9% vs. 41.7%, P=0.004), lower mean forced expiratory volume in 1 second (FEV1) values (46.7% ± 15 vs. 52.3±14%, P=0.001) and a higher prevalence of hypertension (69% vs. 54.3%, P=0.03) and previous cardiovascular disease (34.5% vs. 21.3%, P=0.03). CONCLUSION: There was a high prevalence of asymptomatic PAD in the COPD patients we examined. Abnormal ABI results were associated with a higher prevalence of cardiovascular risk factors and more severe lung disease. The diagnosis of peripheral arterial disease in COPD is important because this is an entity that limits the patient's physical activity and impairs their quality of life in addition to turn it into a high cardiovascular risk patient that requiring additional therapeutic measures.

Quality of thermoplasticized and single point root fillings assessed by micro-computed tomography.

AIM: To evaluate ex vivo the quality of root fillings completed by two thermoplasticized gutta-percha techniques (Thermafil and System B) and a cold gutta-percha technique (single point) by µCT analysis. METHODOLOGY: A total of 30 freshly extracted human single-rooted permanent teeth were selected. Root canals were prepared with ProTaper Universal instruments and then randomly divided into three groups (n = 10) depending on the filling technique. In group 1, canals were filled with a single-point technique; group 2 was filled with Thermafil; in group 3 System B was used. In group 1 and group 3, the root filling was performed using ProTaper Universal gutta-percha points, in group 2 Thermafil obturators were used; AH-Plus sealer was used in all groups. Assessment of the root filling was carried out by µCT, using a desktop X-ray micro focus CT scanner. Percentage of root canal filling materials and voids was calculated for each specimen. Data were statistically analysed using Kruskal-Wallis test (P < 0.05). RESULTS: Mean percentages of filling materials were 98.379 ± 1.204 in the single-point group, 99.023 ± 1.457 in Thermafil group, and 98.167 ± 3.432 in System B group. No statistically significant difference was found amongst the groups. CONCLUSION: All techniques produced comparable results in terms of percentage of filling and void distribution.

Ex vivo-transduced autologous skin fibroblasts expressing human Lim mineralization protein-3 efficiently form new bone in animal models.

Local gene transfer of the human Lim mineralization protein (LMP), a novel intracellular positive regulator of the osteoblast differentiation program, can induce efficient bone formation in rodents. To develop a clinically relevant gene therapy approach to facilitate bone healing, we have used primary dermal fibroblasts transduced ex vivo with Ad.LMP-3 and seeded on a hydroxyapatite/collagen matrix prior to autologous implantation. Here, we demonstrate that genetically modified autologous dermal fibroblasts expressing Ad.LMP-3 are able to induce ectopic bone formation following implantation of the matrix into mouse triceps and paravertebral muscles. Moreover, implantation of the Ad.LMP-3-modified dermal fibroblasts into a rat mandibular bone critical size defect model results in efficient healing, as determined by X-rays, histology and three-dimensional microcomputed tomography (3DmuCT). These results demonstrate the effectiveness of the non-secreted intracellular osteogenic factor LMP-3 in inducing bone formation in vivo. Moreover, the utilization of autologous dermal fibroblasts implanted on a biomaterial represents a promising approach for possible future clinical applications aimed at inducing new bone formation.

Cyclic fatigue resistance and three-dimensional analysis of instruments from two nickel-titanium rotary systems.

AIM: To determine how instrument design affects the fatigue life of two nickel-titanium (Ni-Ti) rotary systems (Mtwo and ProTaper) under cyclic fatigue stress in simulated root canals. METHODOLOGY: Cyclic fatigue testing of instruments was performed in stainless steel artificial canals with radii of curvature of 2 or 5 mm and an angle of curvature of 60 degrees . A total of 260 instruments were rotated until fracture occurred and the number of cycles to failure were recorded. The morphology of Ni-Ti rotary instruments was investigated by measuring the volume of millimetre slices of each instrument size starting from the tip to the shank by means of microCT analysis. The fracture surface of three representative samples of each size was analysed by scanning electron microscopy (SEM). Data were analysed by one-way anova, Holm t-test, paired t-test and linear regression; the significance was determined at the 95% confidence level. RESULTS: Cycles to failure significantly decreased as the instrument volume increased for both the radii of curvature tested (P < 0.01). The radius of curvature had a statistically significant influence on the fatigue life of the instruments (P < 0.05). Larger instruments underwent fracture in less time under cyclic stress than smaller ones. SEM evaluation showed typical features of fracture through fatigue failure. CONCLUSIONS: The metal volume in the point of maximum stress during a cyclic fatigue test could affect the fatigue life of Ni-Ti rotary instruments. The larger the metal volume, the lower the fatigue resistance.

Relationship of contact activation cofactor (CAC) procoagulant activity to kininogen.

Contact activation cofactor (CAC) facilitates the interaction of factors XI and XII. Patients lacking CAC have a coagulation defect and are deficient in high molecular weight kininogen. The coincidence of these two defects suggests that a single protein may be responsible for both physiologic functions. Immunologic and activity studies have been made on isolated CAC to clarify the relationship between CAC and kininogen. CAC forms a single precipitin line with anti-human kininogen, and antikininogen neutralizes CAC activity. CAC and high molecular weight kininogen show a reaction of identity on immunodiffusion against rabbit anti-CAC. Anti-CAC forms two precipitin lines with normal plasma which can be identified as high and low molecular weight kininogen. Monospecific immunoabsorbed anti-CAC forms a single precipitin line with plasma high molecular weight kininogen and neutralizes CAC activity. Cleavage of kinin fragment from CAC by insoluble trypsin or kalikrein does not proportionally reduce procoagulant activity. CAC neutralized by anti-CAC can release kinins on exposure to trypsin or kallikrein. The results support the conclusions that CAC procoagulant activity is a function of high molecular weight kininogen, that antigenic determinants unique to high molecular weight kininogen are shared by the CAC portion of the molecule, and that the clotting reactions may occur at a site removed from the kinin peptide.