The probiotics in dentistry: a narrative review.

The total number of microbes that colonize the human body is far greater than the number of cells that make it up. In recent years, it has been shown that bacteria play an essential role in the body; in fact, they are essential for the maturation of the intestine, the development and control of the immune system, the development of the brain, the metabolism of macronutrients, the synthesis of vitamins, and the energy balance. Bacteria play an essential role in defense of their territory against the entry of other bacteria that may be pathogenic to health. Metchnikoff, about a century ago, invented probiotics, assuming that the use of certain bacteria could be beneficial to maintaining health. Bacteria colonize our body from birth and breastfeeding, using the bacterial flora of the mother by accessing newborns through the mouth. Antibiotic therapies in pregnancy or cesarean section prevent this flow of probiotics to infants and open the way for very important diseases, such as diabetes and obesity. The alterations of oral bacterial flora are responsible for numerous diseases of the oral cavity and the idea of the use of probiotics is leading the way to new therapeutic perspectives.

Zirconia: cementation of prosthetic restorations. Literature review.

AIM OF THE WORK: Aim of the work was to execute a review of the international literature about the cementation of zirconia restorations, analyzing the properties of the cements most commonly used in clinical activities. MATERIALS AND METHODS: It was performed, through PubMed, a bibliographic search on the international literature of the last 10 years using the following limits: studies in English, in vitro studies, randomized clinical trial, reviews, meta-analysis, guide-lines. Were excluded from the search: descriptive studies, case reports, discussion articles, opinion's leader. RESULTS: From studies results that common surface treatments (silanization, acid etching) are ineffective on zirconia because it has an inert surface without glassy component (on which this surface treatments act primarily), instead the sandblasting at 1atm with aluminium oxide (Al(2)O(3)) results significantly effective for the resulting roughening that increase the surface energy and the wettability of the material. Furthermore it has been shown that zinc phosphate-based cements, Bis-GMA-based and glass-ionomer cements can't guarantee a stable long-term adhesion, instead resin cements containing phosphate monomer 10-methacryloyloxyidecyl-dihyidrogenphosphate (MDP) have shown higher adhesion and stability values than the other cements. In particular, it has seen that bond strength of zirconia copings on dentin, using MDP-based cement, is about 6,9MPa; this value is comparable to that obtained with gold copings cementation. CONCLUSIONS: ANALYZED STUDIES HAVE LED TO THE FOLLOWING CONCLUSIONS: sandblasting with aluminium oxide (Al(2)O(3)) is the best surface treatment to improve adhesion between resin cements and zirconia; resin cements containing phosphate ester monomers 10-methacryloyloxyidecyl-dihyidrogenphosphate (MDP) have shown in the studies an higher bond strength and stability after ageing treatment; the best procedure for cementing zirconia restorations results the combination of sandblasting with aluminium oxide (Al(2)O(3)) at 50µm and MDP-based cements.