The use of digital technology has become a useful and also a preferred process in the realization of dental prosthetic restorations, because through it, superior quality dental prostheses are obtained in terms of aesthetics, accuracy of execution and durability. CAD/CAM technology is changing all aspects of dentistry, making dental restoration processes much easier and more efficient for dentists, patients and dental technicians. The materials that can be used to manufacture dental restorations designed using Exocad software depend on the type of restoration (crowns, bridges, veneers, etc.) and the manufacturing method (milling with a 3-, 4-, or 5-axis CAM device); available materials include: PMMA (polymethyl methacrylate) and zirconia. Using digital technology, in this study we performed 6 fixed prosthetic restorations, of which 5 unidental restorations (5 dental crowns) and 1 pluridental restoration (a 4-element dental bridge); of the 6 prosthetic restorations, 3 restorations will be fixed by cementing on dental abutments, and 3 restorations will be fixed by screwing on implants. Digital technology allows the use of higher quality materials, resulting in more resistant and more aesthetic prosthetic restorations; helps reduce the occurrence of errors; obtaining a better marginal adaptation and a perfect adaptation to the anatomical structures of the patient s teeth.

In order to study comparatively the behaviour of the bone-implant interface at mechanical stresses depending on the length of the implant turns, we chose a complex case, a total bimaxillary edentate. 7 implants were virtually inserted into the maxilla (2 pterigoid implants in the lateral regions and 3 implants in the frontal region), and 4 implants were inserted into the mandible (two in the premolar regions and two corresponding to the canines). The FEA analyzes were performed separately for the maxilla and for the mandible, applying a force of 200N on each type of implant. The critical areas, in which the extreme values of the strains develop, are located into the bone on the neck-implant level, and its apex level, regardless of the type of implant and regardless of the maxillary or mandibular area where the implants were virtually inserted. Implants with small turns induce lower stresses and deformations, compared to implants with large turns.

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Objectives. The study aimed to establish correlations between implant geometry, bone density and survival rate of implant therapy. Material and method. The study material consisted of medical documents (clinical observation and treatment sheets, which included both the results of recommended laboratory tests, photographs and imaging investigations performed pre / intra / postoperatively) of patients who were addressed between October 1st, 2014 and October 1st, 2018 to the Oral Rehabilitation Clinic „Prof. Dr. Barbu“. The study included patients wearing mobilizable prostheses, with advanced periodontal diseases that required tooth extraction, patients who accepted dental implants as a treatment solution and presented at all scheduled sessions, including long-term post-therapeutic dispensary of at least 1 year. Statistical processing was performed with Microsoft Excel 2016. Results. The study group included 73 patients of both sexes (28 men and 45 women), old carriers of mobilizable prostheses, with severe periodontal diseases, which required dental extractions. 618 implants were inserted in the study group in order to prosthetic the edentulous gaps. Discussions. The study highlighted the high interest of females in the application of modern dental therapies. At the age group, the 50-59 age group was best represented, closely followed by the 40-49 age group. Most implants were inserted at the upper arch, at a right angle and were conical. Conclusions. Due to the lower bone density in the upper arch, 81.4% of failures occurred in the group studied in the jaw. Implants with small steps between turns have a better prognosis compared to implants with large steps between turns. From the point of view of the type of implant, the cylindrical-conical ones had the best prognosis, and the zygomatic ones registered the weakest prognosis. Bone additions were correlated with a higher failure rate (55.81% of cases). Implants inserted at 10˚ had the best survival rate, and those inserted at 35˚ and 55˚ had the lowest survival rate.

Objectives. Analysis of a group with oral rehabilitation patients with different types of fixed protected restorations, to correlate the therapeutic success rate with the type of aggregation of restorations and with the materials used to fabricate them. Material and methods. The study material was represented by the medical records of one group of the patients with various types of partial edentation. The interest data were collected and were processed with Microsoft Excel statistics from the Office 365 package. Results. The group included: 162 patients (59.56%) with 182 fixed prosthetic restorations with teeth aggregation (of which 106 metal-ceramic restorations, 33 metal-composite restorations, 22 restorations from zirconium with ceramic and 21 all-ceramic restorations) and 110 patients (40.44%) with 140 fixed prosthetic restorations with implant aggregation (72 metal-ceramic restorations, 5 metal-composite restorations, 36 zirconium-ceramic restorations and 27 all-ceramic restorations). Complications detected 3 years after the completion of prosthetic treatment were classified into biological and technical complications. Discussions. In the analyzed group, the metal-ceramic prosthetic restorations were numerically superior to those of integral ceramics or zirconium oxide and ceramics, but we also noticed the presence of metal-composite restorations, preferred by certain categories of patients for economic reasons. In our study we identified 21 technical complications and 19 biological complications. Conclusions. In the group analyzed retrospectively, the therapeutic success rate at 3 years was 87.58%. Metal-ceramic restorations were the main way of rehabilitation applied to edentulous patients. Metal-composite restorations had the highest percentage failure rate, and all-ceramic restorations had the lowest percentage failure rate. The failure rate for prosthetic restorations with teeth aggregation was 14.83%, and the failure rate for restorations with implant aggregation was 9.29%. In order to validate the results obtained, it is necessary to extend the study to larger groups of patients, dispensed for longer periods of time.