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Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Background and Aim: Besides prosthetic and indirect, laboratory-produced restorations, the focus of dental therapy is increasingly on restorative measures and direct restorations as minimally invasive treatment concepts. Thus, the use of direct composite restorations with modern restorative materials for the shaping and recontouring of teeth in combination with orthodontic treatment offers a diversified, extensive sphere of application. The aim of the study was to demonstrate applications for direct composite restorations with reference to selected cases., Material and Methods: The composites used were hybrid composites, which offer increased abrasion resistance and color stability and are applied incrementally. Special attention was paid to the shape, color and structure of the tooth., Case Reports: The case reports present patients in whom relatively narrow or peg-shaped teeth were built up with composite to correct various tooth size discrepancies or cuspids were recontoured by means of direct composite restorations following orthodontic space closure in cases with missing lateral incisors. Similarly, space closure was achieved using orthodontically repositioned lateral incisors recontoured to resemble central incisors after traumatic loss of upper central incisors. Finally, direct composite restorations were used for retention following completion of orthodontic treatment., Conclusions: Observations over recent years confirm the stability of composites in both form and color, as well as their ability to maintain gingival health. Our case reports demonstrate that, subject to a corresponding indication, recontouring single teeth using direct composite restorations can optimize orthodontic treatment results.

In the period from the beginning of 1956 until June 1978, we closed 312 skull gaps with acrylic resin. We used Palacos G (group I) 205 times and Refobacin Palacos R (group II) 107 times. Owing to the antibiotic action of Palacos, the infection rate, which was 6.8 per cent in the first group, could be lowered to 1.07 per cent even with a larger range of indications. The cosmetic results were very satisfactory. Owing to only slight changes in consistency and elasticity, a good protection of the brain was ensured. With the exception of one patient who temporarily showed psychic alterations, the acrylic resin was not felt as a foreign body. Disagreeable sensations, especially in case of the action of heat and cold such as are occasionally mentioned by wearers of metal plates, did not occur in our patients. Formation of neoplasms caused by polymethyl methacrylate has been found in none of the patients during the observation period of 20 years. The plastic repair with acrylic resin can be carried out quickly and in a simple manner. It may be used in all regions of the cranium. Even larger defects can be closed in this way.

Permanent arterial occlusion can be obtained experimentally by using plastic micro-spheres, polymerising materials (Histo-Acryl, Paladur) and direct current thrombosis. Certain limitations in their use arise from the properties of the substances. In our experience, plastic microspheres are not suitable for blocking entire organs or large vascular territories. They are more appropriate for occlusion of individual, small vessels by super-selective injections. Sole use of polymerising materials is not possible; they are best used in combination with other techniques (magnets, balloon catheters). Induction of thrombosis by small direct currents (50 volt, 10 mA). produces permanent and complete occlusion. The method can be used selectively or super-selectively. Unwanted thrombosis can be avoided by using catheters with the smallest possible external diameters.

A novel mucosal adhesive ointment on the base of partly neutralized polymethacrylic acid methyl ester (Eudispert) was formulated. The flow curves of the ointment show a pseudoplastic quality without any thixotropic effect. The viscosity depended on the kind and concentration of the base. During the clinical studies the pure ointment as well as a tretinoin-preparation for a lichen planus treatment showed no local irritation, good mucosal adhesion and suitable way of application for the patients.

Report about 12 cases of defect of the frontal bone: state after radical operation of the frontal sinus (Riedel's operation) or after removal of bone splinters after injury. 6--12 months later a paladon-inlay (acrylate prosthesis) can be implanted to fill the defect and to restore the profile. Description of the production, forming, sterilization and operative implantation of the prosthesis. The patients have been observed up to 18 years. In one case the implanted material was removed after 10 years because of recurrent local suppurations. All the other patients showed an uncomplicated course until today; the cosmetic and functional result was permanently good.

A case of allergic contact dermatitis following the use of a Plexidur finger splint is reported. The allergen was acrylonitrile, one of the original constituents of the polymer Plexidur.