Zirconium - a bioinert metal - in comparison with titanium implants, offers a variety of potential advantages for use in the esthetic area of dentistry due to its tooth-like color. Zirconium dental implants are considered to be an alternative method of treatment to conventional titanium dental implants for patients with a thin gingival biotype. This study was designed to study the bone tissue response to new zirconia implants with modified surfaces in comparison with commercially available titanium dental implants and commercially available zirconia implants. The study was carried out on a group of 12 16-month-old minipigs. New zirconia implants with 3 different surfaces were used: M1 - blasted surface, M2 - etched surface and M3 - blasted and etched surface (Maxon Motor GmbH, Sexau, Germany) and compared to conventional titanium implants with an sandblasted and acid etched (SLA) surface (Straumann GmbH, Freiburg, Germany) and commercially available zirconia implants (Ziterion GmbH, Uffenheim, Germany). Histological and micro-computed tomopgraphy (micro-CT) evaluation was performed. In the micro-CT assessment, the average bone-implant contact (BIC) of the zirconia experimental implants was 41.44%. In particular, the BIC% for M1 was 39.72%, for M2 it was 43.97%, and for M3 - 40.63%; in the control group it was 49.63% and 27.77% for ceramic and titanium control implants, respectively. The intra-group analysis showed no statistically important differences between the BIC values for implants in any group. However, the analysis of BIC for different regions of the same implant showed statistically significant differences in all of the groups between the results of the threaded region and the neck and the apex. The results of our study suggest that zirconia implants with modified surfaces display features of osseointegration similar to those of titanium implants. These results are promising in using zirconia implants for dental applications in the future.

The authors present the contemporary state of knowledge concerning alternative materials for dental implantology. First of all, factors influencing osseointegration are stated. The most important factors seem to be the type of implant surface. Among the numerous parameters describing them, the most important are: average roughness and porous density. Some studies proved that materials with comparable surface roughness provide similar osseointegration. In modern implantology titanium is the material still considered as a "gold standard". However, aesthetic features of titanium still bear several disadvantages, especially in the case of periodontium with a thin biotype in the anterior, aesthetic sensitive area of the jaw. If a titanium implant is used in such a case, the mucosa at the implant's neck may become grayish and, consequently limits the success of the overall treatment. That was the reason for seeking alternative materials to manufacture dental implants. Initiated by general medicine, mainly orthopedics, the search led to the discovery of zirconium dioxide used in dental implantology. A small number of complications, good chemical parameters, anticorrosion, mechanical strength, elasticity module close to the one of steel, and especially biocompatibility made zirconium a perfect material for this purpose, although this material presents several problems in achieving optimal roughness. In this overview one of the probable methods, a process of partial synterization, is presented.

The implant-supported restoration of missing teeth is a recognized method of treatment that ensures a functional, esthetic and durable effect, along with patient satisfaction. However, the preferable time of dental implant loading is under debate. Currently, 3 protocols are used: immediate loading; early loading; and conventional (late) loading. Immediate loading provides benefits such as short treatment time, the elimination of the second surgery required for later loading protocols, the protection of the gingival papilla, an immediate esthetic effect, and high patient satisfaction. This review aimed to summarize the evidence on the impact of loading time on marginal bone loss (MBL) around dental implants, which is considered a useful measure of implantological treatment effects. A literature search was conducted based on the PubMed/MEDLINE database. The search focused on studies providing the MBL values by protocol. Out of the 1,366 hits received in the initial search, 10 studies were included in the qualitative analysis. At 12 months, the MBL range was 0.17-1.86 mm in patients undergoing the immediate protocol, 0.14-1.22 mm in patients undergoing the early protocol, and 0.44-0.91 mm in patients undergoing the late protocol. The studies were heterogeneous, but no significant differences in the occurrence of MBL were reported between the immediately and early loaded implants as compared with the conventionally loaded ones. Further studies are needed to determine other factors that might be related to the type of protocol, important for optimal patient treatment.