[Comparison of oral health in metropolitan and nonmetropolitan district of Leipzig in 1979 and 1989 (ICS I replication study)].

In 1989 the Leipzig-ICS-I study from 1979 was replated according to the same methodology on randomized probands (N = 2693). A significant reduction of the dmft-value (27%) and DMF-value (50 resp. 27%) with clear increased f(F)-value was found at 8/9 and 13/14, years olds.

[Will fluoridation of the drinking water influence the extent of treatment in orthodontic extraction therapy?].

Whether fluoridation of drinking water would have an influence on orthodontic extraction therapy and especially on selection of extraction objects was inquired. Treatment results of 256 patients of a town with fluoridation of drinking water (Chemnitz) who had extraction of teeth under their orthodontic treatment, were interpreted and compared with these of a district without fluoridation of drinking water (Berlin). Evident differences concerning extraction frequency of the various species of teeth were noticed.

[Experiences with gamma-2-free amalgam].

Within a clinical examination the Gamma-2-containing Amalgam "Dentargam", the Gamma-2-reduced "Germadent" and the Gamma-2-free alloy "Duragam" are tested by an intraoral comparison of tooth-paars. A superiority of the alloys with reduced Gamma-2-phases was found.

[Monocentric retrospective study on the prognosis of adenoid cystic carcinoma].

Studies on 26 patients confirm the relevance of the factors tumour size and histological subtype for the prognosis of adenoid cystic carcinoma. For high risk tumours (tumour size over 3 cm, solid or tubular subtype) a postoperative adjuvant radiologic therapy is recommendable. The rate of wrong diagnoses found by reclassification is surprisingly high.

[Ways of tooth conservation by surgical techniques].

Based upon innovations in the past 20 years regarding material--as well as surgical techniques indications are given for surgical conservation of teeth, in addition questions of current interest referring to root fillings are answered. Possible ways of tooth conservation by periodontal operations are shown. To conserve traumatically injured teeth guides for emergency treatment are given.

[Possibilities of root canal filling with gutta-percha. A critical investigation of different techniques].

92 root canal fillings were performed using single guttapercha point with sealer (chloropercha) and lateral condensation of gutta-percha. Neither with single point nor with lateral condensation methods it is possible to achieve advantages in clinical or radiographic success. Nevertheless, the lateral condensation of gutta-percha is a suitable method for beginners to learn the complicated technique of root canal obturation.

[Experimental studies of the proper indication of inlay and crown therapy in lateral tooth areas].

In the framework of a study involving both experimental and clinical tests, two preliminary tests were made to measure and compare the edge lengths of crowns and inlays and the substance losses after tangential and circular stage-type preparations. As revealed by the results, both the three-face and two-face cast fillings in the lateral tooth area have a longer restoration edge than corresponding cast crowns. The weight loss after crown preparations involving a circular stage is greater by one third than after a tangential preparation.