Search

Cell-substratum interactions play a peculiar role in cell proliferation, differentiation and migration. They are regulated by various glycoproteins, among which fibronectin, and by receptors connecting cells to the extracellular matrix, i.e. integrins. Therefore, the aim of this study was to correlate the proliferation rates of the human fibroblast line WI-38 cultured in presence of titanium dental implants to cell adhesion capability to substrata. WI-38 fibroblasts were cultured in presence of four dental implants in titanium (one hydroxyapatite coated) for 48, 72 and 96 hours. Cell proliferation was evaluated by detecting 5-bromodeoxyuridine incorporation. Fibronectin organization and alpha5beta1 integrin expression were evidenced by indirect immunofluorescence. A correlation between fibronectin organization and cell proliferation rates was demonstrated: cultures showing fibronectin mainly organized in fibrils presented the highest cell proliferation degrees. After 96 hours, the observed decrease of the number of proliferating cells corresponded to a different fibronectin organization. In presence of the hydroxyapatite coated implant, colocalization of fibronectin and alpha5beta1 integrin was represented in focal contacts in cultures exhibiting the highest proliferation rate, while cells with the lowest proliferation one expressed alpha5beta1 integrin in point contacts. Evidences obtained in this work showed that both the organization of fibronectin and the expression of alpha5beta1 integrin are strictly correlated to cell proliferation rates. Therefore, these parameters could be useful for evaluating the biocompatibility of dental materials in vitro.

Purpose: The aim of this study was to investigate whether an electrical device for dental adhesive application (ElectroBond) influences bonding of two-step etch-and-rinse adhesives. Materials and Methods: Human teeth were selected and cut perpendicularly to their long axis to expose middle/deep dentin. Specimens were then longitudinally sectioned into halves (experimental and control halves) to create two similar bonding substrates. Experimental halves were bonded using an ElectroBond-assisted application, while control halves were bonded with disposable sponges. The adhesives tested were Adper Scotchbond 1XT and XP-BOND. Bonded specimens were submitted to the microtensile bond strength test. Additional adhesive interfaces were prepared and processed for nanoleakage investigation involving TEM examination. Results: The microtensile bond test revealed higher values (p < 0.05) for both adhesives if ElectroBond was used during layering (55.5 +/- 7.9 IVIPa for Adper Scotchbond 1XT and 54.7 +/- 7.1 IVIPa for XP-BOND) compared to the conventional mechanical adhesive application technique (41.1 +/- 6.1 MPa for Adper Scotchbond 1XT and 38.0 +/- 7.8 MPa for XP-BOND). No difference between the two adhesives was found under the same application conditions. With electricity-assisted application, TEM micrographs revealed a significant decrease in nanoleakage expression compared to the controls. Conclusion: The use of an electric current produced by ElectroBond during the application of two-step etch-and-rinse adhesives may enhance resin impregnation, thus improving dentin hybridization. Further studies should be done to confirm that this device can similarly improve adhesive application in vivo.

Obiettivo: scopo di questo studio è stata la valutazione del sigillo apicale di 3 cementi endodontici. Metodi: sono stati sagomati 88 canali endodontici con strumenti rotanti in Ni-Ti (GT Rotary Files Dentsply Tulsa Dental) successivamente divisi in quattro gruppi test (n=20) e due gruppi di controllo (n=4). I canali endodontici sono stati otturati con guttaperca seconda la metodica System-B in associazione con uno dei seguenti sealers: Pulp Canal Sealer® (gruppo 1), RoekoSeal Automix® (gruppo 2), All Bond 2®+C&B Cement® con primer A+B+Pre-bond (gruppo 3), All Bond 2®+C&B Cement® con solo primer B (gruppo 4). Il gruppo controllo positivo è stato otturato con guttaperca senza sealer. Gli elementi sono stati mantenuti a 37°C ad un’umidità del 100% per 48 ore, successivamente cerati lasciando liberi i due millimetri apicali, ad eccezione dei controlli negativi che sono stati isolati completamente con cera ed immersi per 48 ore a 37°C in India Ink (Pelikan, Hannover, Germany) prima di essere diafanizzati. I valori dei livelli di infiltrazione sono stati analizzati statisticamente con il test ANOVA. Risultati: l'infiltrazione è risultata statisticamente superiore nel gruppo 1 e nel gruppo 3 rispetto ai gruppi 2 e 4 (rispettivamente p

valutazione comparativa di 5 superfici impiantare

Influenza dei perni in fibra sul colore dei restauri estetici: analisi spettrofotometrica

The nature of the bone-implant interface has been much focused in investigating dental implant materials, whereas the relationship between implant and fibroblasts has received much less attention. To evaluate the biocompatibility degree of an implant material, both cell adhesion and cell growth must be tested in the presence of the implant. Four dental implant (A,B,C,D) made in titanium alloy and one of them (C) hydroxyapatite (HA)-coated in fibroblast cultures (48 and 72 h) were tested, by performing immunocytochemical techniques and then by observing fibronectin (FN) arrangement for cell adhesion and counting 5-bromodeoxyuridine (5-BrdU) to evaluate cell proliferation. Different FN arrangements were observed-i.e. organized in fibrils, or in focal adhesion plaques, as well as dispersed in the intercellular space-which varied for the different implants employed at the various culture stages. Equally, the per cent ratio of 5-BrdU positive cells was different, with a more significant increase (p0.001) between 48 and 72 h for implant C and the controls. It was observed that the higher percentages of 5-BrdU positive cells were in cultures where FN was organized mainly in focal adhesions, as well as 5-BrdU positive cells increased after 72 h in cultures, which after 48 h presented much FN dispersed in the intercellular space. It may be assumed that a correlation exists between FN arrangement and the percentage of 5-BrdU positive cells and that these two parameters vary in the presence of the different implants. Moreover, the HA-coated implant seems to be the most biocompatible in fibroblast cultures.

Compomers are defined as polyacid-modified resin composites. They are supposed to combine the advantages of traditional glass-ionomer cements with resin composites. This study clinically evaluated a compomer in cervical cavities. Sixty cervical cavities in premolars and molars (24 with cervical caries and 36 with abrasions) randomly divided into two groups of 30 teeth (Group 1 and Group 2) were restored with Dyract (DeTrey-Dentsply, York, PA 17405-0872). The cavities of Group 2 were etched for 30 seconds with orthophosphoric acid before compomer application, while the Group 1 cavities received no treatment. All the restorations were evaluated every six months, up to 48 months: characteristics assessed according to USPHS-modified standards were retention, secondary caries, post-operative sensitivity, marginal adaptation and discoloration, color and wear. The Kaplan-Meier's survival analysis was performed. In both groups, retention was high without any statistically significant difference. No difference was found between the two groups for caries, post-operative sensitivity and wear--that all had a low incidence. Color was not perfectly matched, however, there was no statistically significant difference between the two groups. Marginal discoloration and marginal adaptation loss were significantly higher in non-etched group (p < 0.05). Clinically relevant failure required 17.2% of restorations in the non-etched group and 10% in the etched group to be replaced: this difference was not statistically significant. Dyract has an acceptable clinical behavior when used in cervical cavities. Its marginal adaptation is enhanced by etching.

Concomitant amplification and expression.

A mutation assay in cultured mammalian cells based on the direct analysis of minisatellite DNA was developed. Band pattern variations reflect DNA alterations ranging from single base changes to complex rearrangements. By DNA fingerprinting a large number of autosomal loci throughout the human genome can be simultaneously checked, therefore minimizing the size of the samples of cell colonies to be scored in the absence of phenotypic selection. For the mutation assay chinese hamster cells (V79) were treated with Nitrosoguanidine and 14 independent colonies were isolated and expanded. DNA fingerprints were obtained after digestion of the DNA extracted from each clone with bothHinfI andHae III, and hybridisation with both 33.15 and 33.6 probes. Twelve colonies from untreated cells were also analysed. Several differences in the band pattern of treated colonies were observed when compared with untreated cells; digestion withHae III and hybridisation with 33.15 probe allowed the detection of the highest frequency of induced variants. The results suggest that minisatellite sequences are hypermutable sites that can be used to monitor the mutagenic potential of chemical agents directly at the DNA level, without phenotypic selection. Moreover, with the method herein decribed, it is possible to distinguish between true mutations and epimutations, such as those caused by changes in DNA methylation.

The aim of the study was to evaluate the reaction exothermia of 2 relining resins for temporary crowns. The resins used were Duralay, a methacrylate-based resin, and Protemp II, a bisacrylic resin. METHODS: The coronal parts of an adult molar and of an impacted one were used. Abutments were obtained from the crowns, while the radicular part was sectioned in order to insert a thermocouple into the pulpal chamber. During the experiment the tooth with the polymerising resin was put into an oral cavity simulator to keep a constant temperature. The thermal increase during polymerisation of the 2 resins was recorded for 6 minutes at 5 seconds intervals and with 1 and 2.5 mm dentin thickness (n = 10). Data were statistically analysed by variance analysis with Scheffe test. RESULTS: The intrapulpal thermal increase was significantly higher in relation to the type of resin (Duralay p < 0.0001), thickness (1 mm p < 0.0001) and type of dentin (young dentin p < 00001). CONCLUSIONS: In order to protect the pulp, during the direct relining of a temporary crown, it is recommendable to choose the best combination among resin, type of dentin and its residual thickness, besides adequate cooling techniques.

Objective: To assess the results of tricuspid annuloplasty performed with the Edwards MC3 remodeling ring. Methods: From 2005 to 2007, 140 patients with tricuspid regurgitation (TR) secondary to left-sided valve disease (mean age 63.8 +/- 11.6, permanent pacemaker in 7.8%, LVEF 56.4 +/- 10.1%, LVEDD 54.1 +/- 8 mm, SPAP 52.5 +/- 14.4 mmHg) underwent tricuspid annuloplasty using the MC3 ring. Dilatation of the tricuspid annulus was present in all patients. Other concomitant mechanisms of TR (moderate leaflet prolapse, pacemaker wires, leaflets' retraction) were documented in 21 cases (15%). All patients underwent concomitant left-sided valve surgery. Ring size was between 28 and 32 in 84.3% of patients. Results: Hospital mortality was 3.5% and actuarial survival at 3 years 94.8 +/- 2.1%. Mean follow-up of the 135 hospital survivors was 22 +/- 9.5 months (median 23 months). Echocardiography at hospital discharge documented no or mild TR in 119 patients (87%), moderate TR (2+/4+) in 15 (11%) and moderate-to-severe (3+/4+) in 1 patient (0.7%). At echocardiographic follow-up moderate TR was present in 14 patients (10.3%) and moderate-to-severe TR in 2 (1.4%). At 3 years freedom from TR >= 2+ was 88.1 +/- 2.78% and freedom from TR >= 3+ was 94.3 +/- 4.89. Predictors of TR >= 2+ at hospital discharge and at follow-up were preoperative LVEF (OR:0.8; p = 0.001 at discharge; HR:0.9; p = 0.003 at follow-up) and the presence of other mechanisms of TR besides annular dilatation (OR:10.8; p = 0.007 at discharge; HR:6.1; p = 0.003 at follow-up). Conclusion: Tricuspid annuloplasty with the MC3 ring provides satisfactory early results which remain stable at mid-term follow-up. The presence of other mechanisms besides annular dilatation leads to residual valve insufficiency after ring annuloplasty alone. doi: 10.1111/j.1540-8191.2012.01443.x (J Card Surg 2012;27:288-294)