The data show that the contention devices with the highest flexibility are the TTS and the Ribbond THM as they exhibit a lower energy variation needed for splint deformation compared with the other materials that were examined.

349 haviour when exposed to forces different from the axial. This would have led to a micro-movement and a mechanical instability at the fixtureabutment connection. Internal connections were developed to eliminate or eventually decrease the micro-movement at the connection level. Various studies investigated the mechanical and clinical implications of different kind of connections assuming that different implant-abutment connections might have different resistance to displacement and stress dissipation under functional load. It seems clear that micro-movement at the implant-abutment interface would have increased inflammation at connection level contributing to a marginal bone loss (2). Authors assumed that it is necessary to improve the mechanical properties of the connections that are actually available and that there is still lack of strong evidence of which of them behaviour better than the others clinically. The aim of this ar-SUMMARY Different implant-abutment connections have been developed in the effort of reducing mechanical and biological failure. The most frequent complications are screw loosening, abutment or implant fracture and marginal bone loss due to overload and bacterial micro-leakage. Ideal connection should work as a one-piece implant avoiding the formation of a micro-gap at the implant-abutment interface. Different in vitro and in vivo researches have been published to compare the implant-abutment connections actually available: external hexagon, internal hexagon and conical finding different amount of micro-gap, micro-leakage and marginal bone loss. The aim of this article is to describe, according to the most recent literature, different kind of fixture-abutment connections and their clinical and mechanical advantages or disadvantages.

The results revealed high reliability of measurements performed on CBCT images independently from object position, examiner's experience and high reproducibility in repeated measurements settings.

BackgroundThe styloid process is a projecton of the temporal bone, its lenght is between 20 to 30 mm, when it is longer than 30 mm it is defined elongated styloid process. The aim of this study is an epidemiological evaluation of 1003 digital panoramic radiographs in an Italian population between 5 and 90 years old.Material and MethodsThis is a retrospective analysis and the radiographs were selected from the Complex Operating Unit of Dentistry of Padua University Hospital database. The radiographs were performed using a Sirona Ortophos XG and the styloid process length was measured using the measuring tool of Sidexis Software. It was measured from the point where it left the temporal bone plate to its tip. Styloid processes measuring more than 30 mm were considered elongated. Chi-squared test, Fligner-Killeen test, Shapiro-Wilk test and t-test with Welch correction were performed.ResultsIn the study 33.40% of the patients showed an elongated styloid process.ConclusionsThe number of patients with elongated styloid process and the mean length of the process increase with the age confirming the chronic development of the calcification described in literature. No statistically significant correlation is found between the presence of elongated styloid process and the gender and affected side (bilateral or unilateral). Key words:Elongated styloid process, panoramic radiograph, epidemiological study, Eagle’s syndrome.