[Replantation of the second molar in the mandible after unsuccessful endodontic treatment]. / Második nagyôrlô replantációja sikertelen endodonciai kezelést követôen. Esetismertetés.

A mandibular second molar after several unsuccessful attempts for orthograde endodontic therapy has been treated by a combined endodontic-surgical approach. The tooth has been atraumatically extracted and a retrograde root canal obturation was performed followed by the reposition of the tooth into its own socket. Wire ligature was used for fixation and the tooth was taken out of the occlusion. After the wire splint was removed the stabilization of the tooth was regularly controlled in the beginning monthly and later on four times a year. Four years after replantation patient has no complaint and the tooth is symptomless. The presented case is one of good examples of the various surgical possibilities, to save seemingly hopeless cases and maintain the natural tooth.

Effect of human organism on the oxide layer formed on titanium osteosynthesis plates: a surface analytical study.

The question of whether or not to remove the titanium osteosynthesis plates used in maxillofacial surgery is not yet answered. These plates can be left a long time in the organism if there is no harmful interaction between the plates and the organism. The authors examined the properties of the surface oxide layers formed on osteosynthesis titanium plates by subsequent thermal and anodic oxidation, together with the properties of plates removed from patients after three years. Surface analytical method Secondary Ion Mass Spectroscopy (SIMS) was chosen. It was found that inside of the about 200-mum thick oxide on the original plates the concentration of impurities is much lower than near the oxide/titanium interface. On the surface of plates removed from the human body, a C (carbon), Ca (calcium) and P (phosphorus) enrichment was detected, suggesting a biological interaction between the organism and the plate. The passivating layer formed with thermal and anodic oxidation has not changed significantly in three years; it resisted to the corrosive effect of the human organism.

[Corrosion study of anodically and thermically surface-treated osteosynthesis plates]. / Anódosan és termikusan felületkezelt osteosynthesis lemezek korróziós vizsgálata.

For the fixation of mandibular fractures, at the Department of Oral Surgery and Dentistry at Semmelweis University, anodically and thermically treated TiO2/Ti osteosynthesis plates are used. The corrosion studies were performed in a generally-applied 3-electrode electrochemical measurement cell, with a calomel electrode as reference electrode, and a Pt net as conducting electrode. The cyclic voltammetric measurements demonstrated that the pore-free surface TiO2 layer forms a highly protective barrier on the surface of Ti. The electrochemical impedance spectrum reflected a decrease in inhomogeneity of the sample because of a decrease in the number of pinholes. Such a change is indicative of passivation. The reported techniques appear to comprise a reliable method of study for an evaluation of the long-term corrosion behaviour of implants.

[Surface analysis of interaction between titan implants treated with anod oxidation and the human organism]. / Anódos oxidációval felületkezelt titánimplantátumok es az emberi szervezet közötti kölcsönhatás vizsgálata felületanalitikai módszerekkel.

UNLABELLED: The examination of interaction between the titan implants treated with anod oxidation and the human organism carried out with surface analytical methods. The favourable properties of metallic titanium have led to its widespread use as an implant material. These properties can be further improved by surface treatment. We have been using anodically oxidized titanium plates for purposes of osteosynthesis for more than 15 years. A specially produced surface oxide layer (TiO2) improves the properties of the metal considerably, increasing the physical and chemical resistance of the plates to the aggressive effects of the organism. Thanks to this, it is now very rare for the plates to have to be removed after the bone healing. The present aim was to use XPS, SIMS and AES surface analytical methods to study the extent to which the positive charactheristics of the TiO2 coating are altered by the aggressive action of the organism during the years following implantation. In practice, we sought to establish the length of time during which the good properties of the plates do not change, and to determine when, it at all, the plates need to removed. MATERIAL AND METHODS: In our present work we studied titanium (ostheosynthesis) plates, removed from 3 patients, with XPS, AES and SIMS method. RESULTS: It was observed that the basic metal remained covered by a TiO2 layer. In consequence of the osseintegration, the Ca and P contents of this layer had increased, which may be explained by incorporation from the organism. CONCLUSION: The Ti implant with is modified surface was covered by a TiO2 layer 120-150 nm thick, which exhibited a homogeneous oxygen distribution. During many years, this had provided protection against the chemical and physical effects of the organism.