Student Rat Daniel Student Rat Daniel Lecturer dr oaita Claudia

Full coverage crowns are one of the most common fixed prosthetic treatments in all over the world, and for many years were made by dental technicians.

Recent technological advancements have introduced alternatives to conventional methods through the use of Computer Aided Design-Computer Assisted Manufacturing(CAD-CAM).

Is a small space between the surface of the prepared tooth and the internal surface of the crown (cement space). Near the gingiva this space is referred to as the marginal gap.

The marginal gap should be as minimal as possible for clinical success. It has been shown that a width of less than 120μm* is clinically acceptable. *Munir Tolga Yucel, Filiz Aykent, Mustafa Cihat Avunduk. In vitro evaluation of the marginal fit of different all-ceramic crowns. 21 June P 225-1

Poor marginal adaptation leads to: -increased plaque retention and subsequent changes in the subgingival microflora leading to periodontal disease and secondary caries.

Additionally, a large marginal gap leads to increased exposure of the luting agent to the oral environment which may cause increased microleakage and cement dissolution.

The aim of this in vitro study was to compare the marginal adaptation of different crowns fabricated with digital and conventional method.

Conventional CAD-CAM System Milled Co- Cr Zirconium Milled wax with lost- wax method Materials and methods

A system was created allowing marginal gap measures in the same points for each subject. Therefore were obtained twenty measures for each crown by direct visualization using a microscope.

CONVENTIONALZIRCONIUCo-Cr FREZATCEARA FREZATA P P P P P P P P P P P P P P P P P P P P

The hypothesis was confirmed, the crowns made with CAD-CAM system turn out to be much better than the crowns made with conventional method The values obtained for those three crowns are below the accepted limit of 120 µ Similar researches have been made by others authors, Per Svanborg 2014, Anders Ortorp 2010, Hisham A. Mously 2014, results obtained by us were similar to them.

Based on the obtained results we can say the following: »different manufacturing techniques affect marginal adaptation »crowns obtained using CAD-CAM system have a much better marginal adaptation than those obtained by conventional method »there were also differences between the results obtained for the crowns fabricated with CAD-CAM, but those differences were small »as expected, zirconium proved to have the best adaptation