The aim of this research was to investigate the retention of a bracket equipped with a novel base, the R-system. The design of the bracket base is characterized by concentric grooves. The behaviour of this bracket was compared with a bracket with a conventional mesh base from the same manufacturer. Thirty lower adult bovine incisors were selected and metallic brackets were bonded using the Concise adhesive system. Each bracket-adhesive-enamel interface was investigated according to torsion debonding. One-way analysis of variance was used for statistical evaluation. Finite element analysis was also undertaken. In order to assess if the technique was detrimental to the enamel, the mode of failure was determined using the Adhesive Remnant Index (ARI). The debonded surfaces were analysed using scanning electron microscopy (SEM) and electron dispersion spectrometry (EDS). The R-system provided a bond strength greater than that of the mesh-base bracket. EDS showed that the amount of calcium on the novel base was higher than that on the conventional base, which allowed transfer of torsional stress more uniformly to the substrate, resulting in higher bond values for the R-system. On the other hand, as debonding of the R-system occurred at the enamel-composite interface, lesions to the enamel substrate are possible.

Zusammenfassung Kraniomandibul?re Dysfunktionen k?nnen auch bei heranwachsenden Patienten vorkommen, die eine kieferorthop?dische Behandlung nachsuchen. Der Kieferorthop?de muss also in der Lage sein, solche Dysfunktionen zu erkennen und zu behandeln, um ein gutes Behandlungsergebnis sowohl in okklusaler, als auch in funktioneller Hinsicht sicherstellen zu k?nnen. Der vorliegende Fallbericht zeigt, auf welche Weise eine Patientin mit Diskusverlagerung ohne Reposition des Diskus, mit kraniomandibul?ren Beschwerden und einer Klasse-II-Malokklusion behandelt werden konnte.