1,720,965 research outputs found
Adhesion and proliferation of human dental pulp stem cells on a laser micro textured implant surface: An in vitro study
Full text linkThe roughness of the implant surface and its chemistery and toporaphy were demonstrated to impact cells biological properties. A moderate roughness seems to allow better and faster adhesion and proliferation and to accelerate the biological processes. The different physical and chemical procedures used to obtain a certain microtopography modify the surface chemical composition and, in consequence of it, can affect the biological cell behavior. The ideal surface shuold be obtained through processes that do not modify the chemical composition maintaining a right roughness and microtopography. The aim of this investigation was to study the morphology, proliferation and pattern of distribution of human Dental Pulp Stem Cells (hDPSCs) after 5 days of growth on a laser micro-grooved implant surface (Laser-Lock, Bio Horizons IPH, Inc. Birmingham, AL 35244, USA) characterized by a micro geometric design obtained by computer-aided laser ablation without any chemical treatment. Data from SEM surface observation and XPS chemical analysis have highlighted the absence of contaminating chemical elements. The results from cell cultures indicated that the hDPSCs maintained a good morphology and well proliferated following the microgrooves direction
Cell behavior related to implant surfaces with different microstructure and chemical composition: an in vitro analysis
No full textThis paper reports on an in vitro comparison of osteoblast and mesenchymal stem cell (MSC) adhesion, proliferation, and differentiation related to two different surface treatments applied to the same implant design to determine whether the interaction between cells and implants is influenced by surface structure and chemical composition of the implants
Reciprocità: il setting e il sociale a cavallo tra gli anni Sessanta e gli anni Settanta
No full textIntroduzione [a Un singolare gatto selvatico: Jean-Jacques Abrahams, l'uomo col magnetofono]
No full textEpithelioid hemangioendothelioma of the mandibular gingiva: report of a case and literature review
No full textBACKGROUND: Malignant epithelioid hemangioendothelioma, or high-risk epithelioid hemangioendothelioma, is a low- to intermediate-grade vascular malignancy originally described by Weiss and Enzinger in 1982 as a vascular neo- plasm of endothelial origin. Epithelioid hemangioendothelio- mas have been reported in numerous locations, particularly the lungs, liver, soft tissues, viscera, skin, and bone. The World Health Organisation describes MEH as an intermedi- ate malignant neoplasm. MEHs are extremely rare in the oral cavity. Only eleven cases referred to MEH of the maxillary or mandibular gingiva.
CASE REPORT: A 33-year-old male was referred to our Oral and Maxillofacial Service in 2009 for the evaluation of a forma- tion on the alveolar mucosa. A panoramic radiograph review showed a radiolucency between lateral incisor and second pre- molar roots. CT scans showed diffuse cortical bone loss. No signs of radiographic root resorption were detected. The patient denied any history of pain or swelling. A tissue punch biopsy was performed by removing two punches of tissue.
A microscopic evaluation revealed fragments composed of a proliferation of spindled, ovoid, and epithelioid cells arranged in nests, cords, and short strands. The neoplastic cells were large and polygonal with an abundant and granular cytoplasm, nuclear pleomorphism, and nuclear hyperchromatism. The lesion exhibited small vascular channels with a moderate cel- lular inflammatory infiltrate, composed mainly of lympho- cytes, plasma cells, and eosinophils surrounding the vessels. Focal mitotic activity was identified, and the Ki-67 percentage score was 20%. After immunohistochemistry a diagnosis of MEH was made. No signs of metastasis were detected (cN0) by an investigation of the patient’s neck nodes, computed tomography, and ultrasonography.
Anterior mandibular bone excision, including eight teeth and all related soft tissues, was performed under general anesthesia. A histologic examination of the lesion confirmed the diagnosis of MEH. The limits of resection were investigated to ensure clean and safe excision margins. No neck dissection was performed at this time.
The patient was followed up at 15 days, 1 month, 3 months, 6 months, and then every 6 months for 4 years with a clinical investigation of soft tissues, clinical and ultrasonographic evaluations of lymph nodes, and radiographic assessment of bone healing. The entire follow-up period was 46 months. DISCUSSION: No consistent clinical or histologic criteria for predicting the biologic behavior of MEHs have been identified. A higher mortality rate is observed when epithelioid hemangioendotheliomas occur in bone, liver, or the lungs; therefore, the importance of immunohistochemical analyses to establish a definitive diagnosis should be emphasised. In this context, the majority of intraoral epithelioid hemangioendothelioma lesions were immunoreactive for CD34, CD31, fac- tor VIII-Rag, and vimentin, which characterise the epithelioid endothelial origin of this entity.
It was not possible to identify common risk factors for MEH. The literature review indicated a mean age at diagnosis for MEH of 17±13.01 years, suggesting a predisposition to dis- ease in young people.
Systemic metastases have been described in the literature at a rate of 21%, and a mortality rate of 17% has been described for cutaneous MEH, in accordance with the histological aspects of the malignancy. In gingival MEH no metastases has been described in literature before our report.
Due to the potential malignancy of epithelioid hemangioen- dotheliomas, wide local excision is the treatment of choice for oral cavity cases according to the literature.
The mean recurrence time was 21.33±23.44 months. Given the possibility of recurrence and metastasis several years after clean and safe excision, clinicians should apply at least 5 years of follow-up
Efficacy of three different irrigation systems on calcium hydroxide removal from round and oval canals: a scanning electron microscopy study
No full textBACKGROUND: To evaluate by means of scanning electron microscopy the effectiveness of different irrigation systems in the removal of calcium hydroxide from round and oval canals. METHODS: 76 extracted single-rooted teeth were selected. Criteria for tooth selection included one single root canal; no visible root caries, fractures, or cracks; and a completely formed apex under light microscope examination (10x). Radiographs in bucco-lingual and mesio-distal direction were taken to cal- culate the ratio between canal diameters measured in the two projections. If ratio was less than or equal to 2.5, the canal was considered round, otherwise was considered oval. According to ratio and root length teeth were divided into 8 groups, with 2 control samples. After access cavity preparation, working length was determined 1 mm short of the length where the file extruded the apical foramen. To simulate clinical conditions the apex was sealed with glue. Glide path and canal instrumentation were performed with Path File size 13, 16, 19 and ProTaper Universal rotary system in a crown-down sequence to size 40 at the WL. A size 25 lentulo spiral was used to fill teeth with calci- um hydroxide. Radiographs were taken to confirm the complete filling of the canals. Samples were kept in an incubator at 37° C for a week. Canals were cleaned with Irrisafe, Endovac, Xp Endo Finisher and conventional endodontic needle irrigation. Teeth were split along their long axis in a bucco-lingual direc- tion into 2 halves. For scanning electron microscopic analysis, tooth halves were fixed on aluminum stubs, gold sputter coated and observed with a scanning electron microscope. Apical, middle, and coronal thirds were established by dividing the roots according to their length. The center of each third was examined at 500x magnification. Images were taken using backscattered mode and analyzed with a digital processing software (ImageJ v. 1.49, National Institutes of Health, NIH, USA) for a quantitative analysis. The efficacy of the irriga- tion system was evaluated calculating the amount of calcium hydroxide left inside the canal, expressed as percentage of the total area of the image. To compare the 8 groups, the results were statistically analyzed using the analysis of variance test (ANOVA) with Bonferroni test or T-test (P<0.05). RESULTS: No statistically significant differences were observed among different thirds for each group. Comparing canal shape for each instrument, significant differences were found only for Endovac, where coronal and middle thirds of oval canals were cleaner than round ones.
Analyzing the whole canal, significant difference can be found between irrigation systems and conventional irrigation in the oval ones. In round canals Irrisafe and Xp Endo Finisher are more effective compared to conventional irrigation, but only Irrisafe is more effective compared to Endovac. No statistical- ly significant differences can be observed between Endovac and conventional irrigation.
CONCLUSIONS: None of the investigated techniques removed the calcium hydroxide completely. However, the results demonstrate greater removal of calcium hydroxide if the irrigant solutions are activated, compared with conven- tional endodontic irrigation. Therefore, it is recommended to activate the irrigant solutions to enhance chemical debride- ment of the root canal system
Effects of titanium brushes on different implant surfaces: an in vivo investigation
No full textBACKGROUND: Recently, rotating brushes with titanium bristles have been introduced for the debridement of implant surfaces when peri implant problems occur. This study inves- tigated the effects induced by titanium brushes on different implant surfaces previously contaminated in vivo METHODS: n°9 disks, going sterilized directly from manu- facturer, (Megagen Implant Co, Ltd, Korea) (n=3 with HA grit sandblasted RBM surface; n=3 with a Ca2+ incorporated in titanium XPEED surface and n=3 with machined surface) Ø 8mm x 3mm were used for this investigation. N°1 disk for each surface treatment (tot. n°3 disks) were characterized at time 0 by SEM to study the surface morphology and by AFM to study the surface roughness. The other six disks were mounted on an acrylic bite embedded in a buccal lateral posi- tion (three for each side) worn for 48 hours by a student from Dental School, for biofilm accumulation. After 48 hours each disk was removed and randomly assigned to the control group (to study only plaque accumulation) and to the test group (toinvestigate the effects of the cleaning procedure using tita- nium brushes). All disks were treated by the same operator. The Nickel-Titanium brushes (I.C.T. De Ore, Verona, Italy) were used (one for each disk treated) mounted on a handpiece at 500 rpm speed and 100 N torque for 60 sec time with a calibrated pressure of 25 gr and a continue irrigation of NaCl 0.9%. All disks were then analyzed by SEM at 40x, 500x and 2000x, also in backscattering, and by AFM for the Ra (medium value of roughness) and Rp-v (max peak-max depth value) measurement. All Ni-Ti brushes used were analyzed by SEM and compared to a no used one.
RESULTS: The MACHINED surface, after instrumentation, appeared well cleansed. However, the SEM images, revealed considerable surface alterations following treatment. The roughness values increased. The RBM surface showed a mini- mum percentage of residual material and after cleaning had some morphological changes. The typical RBM sandblasted structure appear flattened. The roughness values confirm this change by the reduction in value of R p-v. The cleaning effi- cacy of the brush on the XPEED surface was excellent but the surface morphology changed. The SEM images showed the presence of grooves and flattening caused by the use of brush that have eliminated most of the irregularities and of the peaks, confirmed by the roughness values measured. The EDX spectroscopy provided the evidence that part of the Ca ++ ions coating remains on the surface even after treatment. The statistical analysis shows that the Ra difference was statis- tically significant. (p<0.5) The brush used for Xpeed surface is the only one, among those used, that appeared more com- promised after its use. The bristles are very twisted. CONCLUSIONS: In conclusion we can say that the trial of toothbrushes NiTi has shown a good efficacy of cleansing on rough and smooth surfaces. The efficiency of the treatment was, however, accompanied by a visible change in the surface characteristics. While the machined surface at the end of treat- ment showed an increase of roughness values, the rough sur- faces undergo a flattening process with consequent decrease of the roughness measurements. Further studies will be needed to verify if and how these morphological changes will affect biological processes of healing
Oral atrophic lichen planus and oral lichenoid lesion malignant transformation: report and management of two cases
No full textBACKGROUND: There is an ongoing debate in the literature whether patients with oral lichen planus (OLP) carry an increased risk of developing a squamous cell carcinomas. Nevertheless, there is a tendency to accept that there is. The annual malignant transformation rate amounting less than 0.5%. This chronic disorder mainly affects middle-aged people. The etiopathogenesis is still poorly understood. There is no effective treatment and there are no preventive measures either. An important obstacle in the discussion on the possible potentially malignant character of oral lichen planus is caused by the lack of clear clinical and histopathologic diag- nostic criteria of oral lichen planus, resulting in a poor clin- icopathologic correlation in the diagnosis. One of the major problems of interpretation of malignant potential studies of OLP is the inexistence of strict diagnostic criteria to differentiate lichenoid processes. Some studies have included cases of OLP with OLL and vice versa. The differentiation between OLP and OLL has become important, since the latter might have a greater malignant potential. For this reason, it is important to establish precise clinical and histopathological criteria of differentiation of the lesions.
CASE REPORT: 1st) A 73 years old woman with a 12 months histological diagnosis of oral lichen planus localized on tongue dorsum, previously biopsied and studied in a differ- ent structure, came to our attention to investigate an ulcerative lesion on tongue midline. No smoking habit, alcohol abuse, anemia or previous malignancies diagnosis were referred; topical corticosteroid therapy was referred.
An incisional biopsy was performed showing lichenoid lesion, atypia and high grade of dysplasia at histological examination. Subsequently, lesion was radically removed with wide excision margins. Microscopic examination returned diagnosis of mild differentiated squamous cell carcinoma arose on lichenoid lesion. Resection margins were clean without perineural or vascular invasion.
After 18 months follow-up, symptoms of dull pain and burn sensation were referred. Tongue dorsum was macroscopically altered, with an ulcer-like lesion surrounded by edematous mucosa. Consequently, an incisional biopsy was performed showing the presence of a low differentiated squamous cell carcinoma. Lesion was radically excised, margins were widened and examined with frozen sections. Patient underwent to bilateral SND (level I-III) and RTP.
Histological examination returns a diagnosis of recurrent pT1 pN1 micro-invasive squamous cell carcinoma. Microscopic signs of lichenoid lesion were still evident.
2nd) A 74 years old woman, with a 20 months history o
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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