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Aim: The process of twisting has been used for decades to fabricate stainless steel instruments, but it was previously thought to be an impractical method for nickel-titanium (Ni-Ti) instrument manufacture A manufacturing method of twisting Nickel-Titanium wire to produce Ni-Ti files has been recently developed: the twisted files (TF). Theoretically, this new manufacturing process should overcome the problems associated with a grinding process, which previously limited instrument strength. Since TF manufacturing process is new and different from grinding, the aim of the present study was to evaluate the effects of a final deoxidation process (Deox) on torsional resistance of TF instruments., Methods: Testing was performed in accordance with the International Standard (ISO 3630-1) by comparing 20 TF instruments versus 20 TF prototype instruments produced without the final deoxidation process. Data were collected and statistically analyzed (t-test)., Results: Results show that TF instruments withstood 90% more torque (max. torque) than TF prototype instruments manufactured without the deoxidation process (88.7 vs. 53.3 g/cm). This difference was found to be statistically significant at the 0.05 level of significance., Conclusion: Since design and dimensions of tested instruments were the same, the deoxidation process could be the only explanation of the improvement in torsional resistance.

Ameloblastic fibroma (AF) is defined in WHO classification as a ''neoplasm composed of proliferating odontogenic epithelium embedded in a cellular ectomesenchymal tissue that resembles dental papilla, and with varying degrees of inductive change and dental hard tissue formation''. AF is a rather uncommon tumor, accounting for only 2.5% of all odontogenic tumors. AF is a true mixed tumor, in which the epithelial and ectomesenchymal elements are neoplastic. AF raises at any age, ranging from 6 months to 42 years (mean 14.6 to 15.5 years); it does not show sex predilection. The lesion occurs in nearly 70% of cases in posterior areas of the mandible. Patients exhibit swelling of the jaw; pain is not usually described. Authors present a clinical and surgical management of an early onset of a large mandibular ameloblastic fibroma in a 6-year-old girsl.

Aim: The aim of the present study was to evaluate the bending properties of twisted file instruments, and compare them with other commercially available nickel-titanium (NiTi) instruments (Mtwo and Hero) manufactured with traditional methods., Methods: Despite NiTi superelastic properties, flexibility of NiTi instruments is limited by size and taper. A new manufacturing process involving twisting of a ground blank combined with heat treatment has been developed by SybronEndo, aiming to produce a NiTI rotary file with superior flexibility: the Twisted File (TF). Experimental procedures strictly followed the testing methodology described in ISO 3630-1. Bending moment was measured when the instrument attained a 45 degrees bend. Data were collected and statistically analyzed., Results: Results showed that TF were the most flexible instruments, with a significant improvement in flexibility (P< 0.05). ranging from 100% to 250% over the other tested instruments. Even if flexibility is also influenced by instruments design, such a great improvement is mainly related to the new TF manufacturing process., Conclusion: The flexibility is influenced by instruments design, such a great improvement is mainly related to the new manufacturing process developed by SybronEndo, which seems to play a major role in increasing the flexibility of TF instruments.

Aim: Several studies have reported that dental resin-based materials release substances with biological activity: for this reason in this study we evaluated the in vitro cytopathic effects of a self-curing and a light-curing orthodontic composite resins by a cytotoxicity test., Methods: The cytotoxic potential of specimens, prepared according to the manufacturer instructions, was evaluated using the thiazolyl blue tetrazolium bromide (MTT) assay on the mouse fibroblast cell line (3T3 Swiss) with 2 cells-material contact systems: the 24 h extracts method and the indirect toxicity method., Results: The results obtained in this study elicit a close agreement between the 2 procedures; from the data obtained in the reported experimental conditions, it was possible to establish that the examined chemical-cured material is more cytotoxic than the light-cured one., Conclusions: From a clinical point of view, the photo-polymerizable resins are undoubtedly more useful in the daily practice, because of the larger precision of the bonding obtainable by the greater period available for setting the brackets before their lock. The results obtained in this study, even considering the limits of the in vitro tests, represent a further favourable feature of the light-curing composite resins. However, further investigations about the influence of polymerization methods of the materials on the biological effects are suggested to contribute to the determination of the best clinical operative conditions.

Aim: The effect of cycles of sterilization procedures on nickel-titanium (NiTi) endodontic instruments is a serious concern for practitioners. There is no agreement in the literature whether these procedures could adversely affect the mechanical properties of endodontic files, and, consequently, increase the risk of intracanal failure. The purpose of this study was to evaluate the mechanichal resistance of Hero (MicroMega, Besancon, France) instruments, before and after sterilization procedures., Methods: Thirty 02, 04, 06 tapered Hero size 30 new instruments were chosen and divided into 3 groups. Group A (control) were tested according to ANSI/ADA Spec.no 28 for torsional resistance, angle of torque and angle at breakage (45 inverted exclamation mark ). Group B files were first sterilized with chemiclave for 10 cycles of 20 minutes at 124 inverted exclamation mark C and then tested as described above. Group C files were first sterilized with glass beads for 10 cycles of 20 sec. at 250 inverted exclamation mark C and then tested as described above. Data were collected and statistically analyzed (t-paired test). Differences among the 3 groups were statistically not significant for both tests., Results: All data were well within Spec.no 28 standard values., Conclusion: From the results of the present study, we may conclude that repeated sterilization procedures do not adversely affect the mechanichal resistance of Hero files.

Background: An adequate film thickness is an important property of an endodontic sealer, when used in combination with gutta-percha, to eventually fill minimal voids between gutta-percha and the root canal walls, ensuring an hermetic three-dimensional root canal obturation. The goal of the present study was to evaluate the film thickness of the following five root canal sealers: RSA, Rocanal R4, N2, Bioseal and Acroseal., Methods: The testing procedures strictly followed ANSI/ADA spec. no. 57 for endodontic filling materials. All root canal sealers were mixed at room temperature strictly following mixing procedures advised by manufacturers. A small amount of sealer was placed between two glass plates and load of 147 N was applied vertically on the top glass plate. After 10 min, the thickness of sealers was measured by a micrometer assembled on a stereomicroscope (Lomo MBC 10). Data were collected and statistically analysed., Results: Results (expressed in micron) were the following: RSA=9,3 (+/-1), Rocanal R4 95 (+/-12), N2 50 (+/-23), Bioseal 41 (+/-13) and Acroseal =9 (+/-2.55)., Conclusions: RSA and Acroseal showed the best results (a statistically significant difference was noted among these sealers and the others). On the other hand Bioseal and (partially) N2 showed values compatible with a valid clinical use, while Rocanal R4 showed values higher than minimum standard values allowed by ANSA/ADA spec. no. 57.

The authors emphasize the need to set up several products proposed by the manufacturers. Regarding to orthodontic wires, a suitable evaluation of their mechanical properties to fit them for clinical use is needed. After a short outline of the mechanical properties of the wires on the market, the authors focus their attention on the NiTi Japanese alloy superelastic wires. Therefore, an evaluation of the failure aspect of NiTi preformed arch wires with round section of 0.018" of diameter is reported. The tested wires underwent to clinical use as first arch wires, and were evaluated after 8 weeks from the beginning of the therapy, when they have shown failure at the control in the 8th week. After having cleansed and prepared the specimens, their failure zones have been observed by the SEM. The failure aspect was evaluated to check the reasons that produced it, basing on its surface characteristics. The aspect of the surface of the failure and the absence of permanent deformations showed that it is a fragile failure. The fragile failure occurs when materials are not able to tolerate plastic deformations and, typically concerning NiTi alloys constituent the tested wires, it joins the superelastic behaviour and the high wire resilience. It means that this wire is able to produce constant, continuous and light forces for a given stress range, and, furthermore, it is able to absorb energy without permanent deformations. Since 1971 NiTi wires have been on the market but without superelastic and crystallographic shape memory properties possessed by the wires produced by Furukawa El. Co. in 1978.(ABSTRACT TRUNCATED AT 250 WORDS)

The efficacy and tolerability of a new pharmaceutical formulation of a non-steroid anti-inflammatory drug, nimesulide were studied in a double blind study in comparison with flurbiprofen and diclofenac sodium, in 150 patients suffering from postsurgical pain-inflammatory symptoms. The three drugs, administered in a dose of one suppository twice a day for 10 days, showed marked anti-inflammatory, analgesic and antipyretic activity and produced a significant, progressive improvement in the typical symptoms of the inflammatory state. Nimesulide evidenced the greatest speed and duration of therapeutic action. Assessment on the efficacy and tolerability as expressed separately by the physician and the patients were positive in almost all cases of the three treatments.

Based on an extensive review of the literature, the authors examine immunological reactions in pulpal and periapical lesions. Although it has been known for some time that bacterial infection causes this pathology, attention has been recently focused on immunological factors in the ambit of the phlogistic process. The present study examines the correlation between the latter and the type of extent of antigenic response, focusing attention on their important role in the phenomena of osteoclastic activation and inhibition of bone repair. From a physiological point of view there are few inflammatory cells in dental pulp, like macrophages and T lymphocytes. When the pulp comes into contact with the antigenic substance it activates a specific and aspecific immune response: the form through the activation of B and T lymphocytes, and the latter through the action of LPS, PMN and complement. An important role in the immune response is played by the cytokines which are able to regulate the intensity and duration of the immune response against potential pathogenic agents. It was initially thought that these were only produced by lymphocytes and as a result they were known as lymphokines. Later it was observed that other cell populations were also able to produce them. Phlogosis of the periapex starts before the pulp is fully necrotic. Tissue detritus and products of bacterial derivation escape through the numerous endoparadontal communication pathways and stimulate an inflammatory response by the vascular system of the parodontal ligament. The concomitant immune reaction occurs due to the tendency to block and restrict the inflammation to the radicular channels, thus preventing its diffusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Different kinds of spreaders can be used in the lateral condensation technique. Selection of condensation instruments must not be empirical because the quality of the filling partly depends on the compatibility between the spreader and the prepared root canal. The shape of the instrument should allow for easy insertion to the proper length without any interference. On these bases the Authors evaluated and compared the morphology of some spreaders, and gave data and directions how to rationally use these instruments in clinical practice.

The aim of the present study was to establish the prevalence and the type of psychiatric disturbances in a group of 42 obese children (18 boys aged from 6.8 to 13.8 years and 24 girls aged from 2.8 to 15.4 years; weight excess mean +/- 1SD 146.7 +/- 17.4%) and to evaluate the efficacy of a psychological approach of obesity in childhood. The children were in a normal caloric diet and they were encouraged to reach a "target weight" in a given period of time. 22 children were randomly assigned the "analyzed" group (auxological, alimentary and psychological evaluation) and 20 to the "control" group (auxological and alimentary assessment). The psychological evaluation was performed in 20 children (the parents of two children refused to give their consent) by the following tests: creative drawing test; draw a man test (Machover); draw a tree test (Koch); draw a family test (Co-man); Rorschach's test; TAT (Thematic Apperception Test) or, in the younger, the Düss's tales. The results of these psychological tests have been communicated to the patients and or parents. The children were followed for a period of 7 months. We found in 8 children (40%) personality disturbances (which were severe in two cases) and a psychological support was started. The observed main types of disturbances were depression and anxiety. Both were due to a missing harmony between their parents, to a difficult relationship either with their mother or with other children, and to the bad child's opinion of himself. In 4 subjects a psychological support associated with diet promoted a slow, progressive and continuous weight loss.(ABSTRACT TRUNCATED AT 250 WORDS)