Decision-making process as guide to the management of non-carious cervical lesions with and without painful symptomatology.

The aim of this study is to develop a decision-making path for the management of non-carious cervical lesions (NCCLs) associated with or without dentin hypersensitivity (DH) This will allow to limit or delay invasive approaches identifying the causes that produced them. The need for this review is because there are no clear guidelines in the current literature for the treatment of NCCLs. Usually, the selection of the best therapy option is postponed to clinical judgment which can be influenced by a patient's demands (aesthetic, symptomatologic reasons or worsening of pre-existing NCCL). To establish a therapeutic plan the young dentist should be able to distinguish the NCCLs that need to be monitored over time from those in need of early treatment. Indeed, the experience of the dentist and the compliance of the patient play a decisive role for the success of the therapy.

Dentin caries progression and the role of metalloproteinases: an update.

AIM: This review aims to summarise our understanding of the destructive role of acid environment and metalloproteinases in dentin caries progression using a review process. METHOD: The acids resulting from consumption of sugars by acidogenic and aciduric bacteria can cause demineralisation of the tooth surface, but are not able to cause caries-like lesions. The appearance of such lesions requires the activation of enzymatic proteolysis in an acidic environment for degradation of the dentin organic matrix, leading to cavity formation. Bacterial collagenases have long been considered responsible for organic matrix destruction; host cell-derived matrix metalloproteinases (MMPs) have recently been considered to be involved in the dentinal matrix destruction of carious lesions. DISCUSSION AND CONCLUSION: MMPs are initially synthesised as inactive zymogens to be activated in acid environment of dentinal fluid during the carious process, resulting in destruction of the collagenous matrix. The role of acid environment on enamel and dentin demineralisation and the role of salivary and dentinal MMPs in dentin progression of caries has encouraged general dentists to include the monitoring of oral environment not only by control of bacterial oral flora in caries treatment protocol, but mainly by inhibition of dentinal and salivary MMPs through the use of toothpaste and/or mouthwash containing specific active agents.

Hard X-Ray Emission from the Galaxy Cluster A2256.

After the positive detection by BeppoSAX of hard X-ray radiation up to approximately 80 keV in the Coma Cluster spectrum, we present evidence for nonthermal emission from A2256 in excess of thermal emission at a 4.6 sigma confidence level. In addition to this power-law component, a second nonthermal component already detected by ASCA could be present in the X-ray spectrum of the cluster, which is not surprising given the complex radio morphology of the cluster central region. The spectral index of the hard tail detected by the Phoswich Detection System on board BeppoSAX is marginally consistent with that expected for the inverse Compton model. A value of approximately 0.05 µG is derived for the intracluster magnetic field of the extended radio emission in the northern regions of the cluster, while a higher value of approximately 0.5 µG could be present in the central radio halo, which is likely related to the hard tail detected by ASCA.

Interaction in Abell 2256: The BeppoSAX View.

We present results from a spatially resolved spectral analysis of the merging cluster Abell 2256. The long integration time (135 ks) and the good spatial resolution of the Medium-Energy Concentrator/Spectrometer on board BeppoSAX allow us to derive a new and substantially improved measurement of the temperature structure. We find that, within a central region of the cluster, where the effects of the merger are visible in the ROSAT surface brightness image, the azimuthally averaged projected temperature is remarkably flat; outside this region, the projected temperature rapidly declines. The BeppoSAX data also show clear evidence of an azimuthal temperature gradient in the 4&arcmin;-8&arcmin; (0.4-0.8 Mpc) radial bin, oriented in the same direction as the merger itself. Our metal abundance profile shows, for the first time, firm evidence of an abundance gradient in a rich merging cluster. Intriguingly, the abundance map shows, in the southeast sector, i.e., the one farthest away from the merger, a sharp factor of 2 drop in abundance at a radius comparable to the core radius of the cluster. A possible interpretation is that prior to the merger event, a cooling flow had already developed in the core of the infalling subgroup, as suggested by Fabian & Daines. The interaction between the substructures would have disrupted the cooling flow, thereby reheating and remixing the gas. Since the merger in A2256 is still in a relatively early stage, the gas located on the side opposite the merger event would still retain the low abundances associated with the intracluster medium prior to the cooling flow disruption.

The BeppoSAX View of the Hot Cluster Abell 2319.

We present results from a BeppoSAX observation of the rich cluster Abell 2319. The broadband spectrum (2-50 keV) of the cluster can be adequately represented by an optically thin thermal emission model with a temperature of 9.6+/-0.3 keV and a metal abundance of 0.25+/-0.03 in solar units and with no evidence of a hard X-ray excess in the PDS spectrum. From the upper limit to the hard-tail component, we derive a lower limit of approximately 0.04 µG for the volume-averaged intracluster magnetic field. By performing spatially resolved spectroscopy in the medium energy band (2-10 keV), we find that the projected radial temperature and metal abundance profiles are constant out to a radius of 16&arcmin; (1.4 Mpc). A reduction of the temperature of one-third, when going from the cluster core out to 16&arcmin;, can be excluded in the present data at the 99% confidence level. From the analysis of the temperature and abundance maps, we find evidence of a temperature enhancement and of an abundance decrement in a region localized 6&arcmin;-8&arcmin; northeast of the core, where a merger event may be taking place. Finally, the temperature map indicates that the subcluster located northwest of the main cluster may be somewhat cooler than the rest of the cluster.