Early carious lesions induce odontoblast stimulation in tertiary dentine formation even before the lesion reaches the dentine. The most used material for these procedures was calcium hydroxide, which was recently replaced by Mineral Trioxide Aggregate (MTA).The purpose of our study was to assess the histological characteristics of tertiary dentine induced by these materials in permanent molar teeth.We used 23 molars scheduled for extraction due to orthodontic reasons, in patients of 17-24 years of age. In a time interval of 4-8 weeks prior to extraction, occlusal cavities were prepared and filled with MTA or calcium hydroxide and glass ionomer cement.In teeth filled with MTA we noticed an early development of tertiary dentin layer, with a tubular structure, similar to secondary dentine. In the case of calcium hydroxide, the process of new dentine deposition was delayed and diffuse calcification, with formation of pulp stones was noticed.MTA proved to be superior to calcium hydroxide in inducing tertiary dentine formation, which appeared early after treatment. In time the differences in the amount of tertiary dentine between these materials are reduced, but there is a tendency of diffuse mineralization induced by calcium hydroxide.

Biocompatibility has been defined as the ability of a material to function in a specific site, in contact with host tissues but without inducing any undesirable local or systemic reaction.The aim of this study is to evaluate the biocompatibility of calcium hydroxide-based endodontic sealers and to compare it with a resin-based material, by measuring the degree of inflammation induced by these products after subcutaneous implantation in rats. We used 12 animals divided in 3 study groups and 1 control group; implants with Mineral Trioxide Aggregate (MTA), AH26 and Sealapex were placed in subcutaneous tissue and histological evaluation was carried out after 7, 14 and 21 days. We obtained comparable results between MTA and Sealapex, which demonstrates that these materials have similar degrees of biocompatibility. Based on this experimental study, calcium hydroxide containing cements express similar biocompatibilities. Further clinical studies are necessary in order to evaluate the healing properties and apical seal of these materials.

<p class="TTPAbstract">The brackets collating technique and microbial factors increase the risk for enamel demineralization in patients with fixed orthodontic appliance. The aim of this study was to determine the risk level of enamel demineralization in fixed orthodontic device bearers. The enamel demineralization was assessed in 187 patients by measuring dental structure by fluorescent light. The measurements were performed with the DIAGNOdent Pen 2190 (KaVo, Biberach, Germany). Except canines which remain in the risk 1 category, without enamel demineralization, the other investigated teeth may have a medium demineralization degree The values recorded with fluorescent light on canine enamel showed low and insignificant differences (p>0.05) as a result of fixed orthodontic appliances, classifying these teeth as healthy teeth with enamel integrity or with low enamel demineralization. The molars presented significantly increased values in the study group as compared to the control group (p<0.05). 6 years molars had a marked predisposition to demineralization and caries as compared to frontal group teeth, after fluorescent light measurements. The measurements include these teeth in the medium to high risk for dental caries. The DIAGNOdent, due to its capacity to determine the demineralization degree of dental surfaces, may be used to monitor patients and to prevent the occurrence of dental caries during fixed orthodontic treatments.<o:p></o:p></p>

Over the past three decades, nickel-titanium engine-driven files have become instruments "sine qua non" for root canal treatment. They are increasingly used by dentists to facilitate the cleaning and shaping of root canals, during the mechanical treatment phase in endodontic therapy, increasing not only the speed of the treatment but also assuring a proper shape of the canal preparation. During the repeated use of these instruments, separation of the file occurs. It has been demonstrated that the failure of the instruments can appear due to the torsional stress or cyclic loading, or a combination of both. Our study was meant to explore the surface and the non-organic structure of the fractured instruments, using SEM analysis. Extracted teeth' roots were prepared with Bio-RaCe (FKG, Le Chaux-of-Fonds, Switzerland) until the instrument fracture occurred. In order to reduce friction between the root canal wall and the instrument, the root canal was rinsed both with NaOCl and EDTA. The corrosive environment of both rinsing agents may be noticed on SEM images, scoring as a severe surface defect with 10 points, out of the maximum 11. Both are corrosive agents, used to eliminate the debris, bacterial agents and to soften the hard tissue. The moment the first instrument separated (BR3 25/.06.) we scored all the files, noticing on SEM analysis all the changes that occurred. Opposed to the current trend of using as less files as possible, we consider it a dangerous simplification of the preparation procedure. A step by step taper increasing is less dangerous, providing thus, a predictable outcome of the treatment. For a safer treatment and a positive outcome, a full kit of files (from 10 to 50) with a taper of 4 is recommended before using the same size files with a greater taper.

The correct endodontic treatment involves the exact determination of the working length. This is accomplished by combining several techniques: the tactile technique, X-ray with the needle or the endodontic probe in the root canal and comparing with the average tooth length.The determination of average tooth length depends on the geographic area. The current table used in practice contains the values gathered on a population group that is different than ours; the table has been made on Caucasian subjects.In conclusion, our study aims to determine the proper average values of our geographic zone, the table obtained by completing the equation of the endodontic therapy that will admit the proximity of the Romanian reality.