[Biocompatibility of composites--literature review].

Composites are a large family of materials composed of polymer matrices imbedded with different types of fillers. The specific properties achievable with diverse chemical combinations provide for a wide range of implications in many industrial fields. Materials designed for medical use must not only efficiently serve the purpose of their use, but also be biocompatible to the tissues they contact and the body as a whole. Dental composites and their components have been studied intensely to assess their potential local and systemic side effects, to establish biocompatibility, in order to receive the proper conformation allowing their safe clinical use. The purpose of the following paper is to summarize several aspects of research focused on determining cytotoxicity, genotoxicity, carcinogenicity, hypersensitivity, and microbial effects of composite components, in order to ascertain in fact how biocompatible dental composite materials are. Research shows that several chemical components may be released from different types of composites, and are able to cause toxic, allergic, mutagenic and other biological effects. However, because of the small amounts applied and the unique conditions in the oral cavity, the clinical relevance of these findings is questionable. Nevertheless, caution should be taken when using these materials, to avoid possible negative outcomes. Future studies should focus on targeting most toxic components and finding biocompatible alternatives and development of materials with high polymerization efficiency in order to reduce the amount of leachable components.

[A tooth or an implant--literature based decision making].

The common use of dental implants in the daily practice led to a profound change in the available treatment strategies. The option of replacing a diagnosed doubtful tooth with an implant has become widely accepted and often used. The prognosis systems in use today are based on the three major disciplines: endodontics, periodontics and prosthodontics. Combining these three may impair and bias the decision making process and increase the tendency to base it on subjective clinical experience and personal preference. Reading and reviewing the relevant literature gives no clear tool for use. Root canal treatment is considered a highly predictable treatment procedure and a treated tooth is affected mainly by the quality and type of the fabricated restoration and the risk of caries. Periodontal treatment followed by a suitable maintenance regimen will likely allow long term tooth survival. When comparing the success rates of natural teeth rehabilitation versus implant supported restorations, it appears that with implants an additional treatment is demanded along the years. This coincides with the fact that to date there is no consensus regarding the extent of perimplantitis and perimucositis that is to be expected around a restored implant. In addition, a peri implant tissue problem or a failure of a dental implant may prove to be more challenging than a failure of a tooth. It is important to remember that a dental implant is made to substitute a missing tooth and it is a treatment modality with known and clear indications for rehabilitation of an edentulous space. The aim of this paper is to review and discuss the various aspects of whether to maintain a compromised or a doubtful tooth or to prefer a treatment modality using dental implants. In conclusion it is advised here, to incorporate the discussed issues in the decision making process towards the most suitable treatment plan.

[Retention or adhesion?].

One of the reasons for immediate or late failure of restorations is the detachment of the restoration from the tooth. Retention for the restoration could be achieved from axial walls (macromechanical retention) or from adhesion of the restoration to the remaining tooth structure. Adhesion relies on bonding of resin cement to enamel or dentin on one side and to the restorative material on the other side. Bonding to enamel is predictable. Good bonding to dentin is more of a challenge especially with indirect restorations. In those cases the restoration is delivered usually a few days after the tooth was prepared during this time the exposed dentin might be contaminated or damaged. The question is whether you can rely on adhesion when cementing indirect restorations? In order to achieve the maximal bonding strength to dentin, the hybrid layer on the dentin must be built immediately after tooth preparation. This procedure is called Immediate Dentin Sealing. In vitro and clinical studies have shown better performance of restorations cemented following the IDS procedure. The article discusses the rational and the protocol of this procedure. A clinical case is presented as an example for the possibilities following this philosophy.