Zum Einfluss von Speichelkontamination und -Dekontamination auf die Dentinhaftung in Klasse-I-Kavitäten in vitro

The aim of this in vitro study was to investigate the influence of saliva contamination and decontamination on dentin adhesion of Prime&Bond active in Class-I cavities. Materials and methods: In this experimental in-vitro study, 42 extracted caries-free human third molars were selected for the preparation of Class-I cavities of 5x5x4mm. The teeth were randomly assigned to seven groups (n=6). The groups differed in terms of saliva contamination or decontamination and duration of application of the universal adhesive Prime&Bond active (PBa). With the exception of the control group, fresh human saliva was applied to all groups (1-6) for 10 seconds, then dried in group 1, decontaminated with water spray in group 2 and with alcohol swab in group 3. Subsequently, the PBa was applied according to the manufacturer's instructions. In groups 4 and 5, saliva was just air-dried and the application time was extended to 60 seconds in group 4, and to 120 s in group 5. The universal adhesive was applied to the saliva-wet dentin in group 6 with-out prior decontamination according to the manufacturer's instructions. Subsequently, after at least 24 hours of water storage at room temperature, specimens were cut in resin-dentin beams at a 90° angle to the interface. Microtensile bond strength of the specimens was examined at a crosshead speed of 1mm/min. Micromorphological analysis of the interfaces to assess fracture patterns was carried out after sputtering the dentin components using a scanning electron microscope. Results and observations: The control group showed the significantly highest microtensile bond strength com-pared to saliva-contaminated groups (p<0.05). Groups 4 and 5, where both duration and number of application steps were increased, showed the second highest bond strength without reaching initial values (p<0.05). Groups 3 and 4 exhibited significant-ly lower adhesion values even after decontamination (p<0.05). There was no signifi-cant difference regarding the type of decontamination (p>0.05). Furthermore, it could be shown that the bond strength values were lowest after application of PBa on dried saliva, as well as after application on wet saliva (p<0.05). Conclusion: From the results of this in-vitro study it can be deduced that the tensile strength of the universal adhesive Prime&Bond active, after contamination with saliva and application of the adhesive according to the manufacturer's instructions, is lower than when used without saliva contamination. An increase in the duration of application, as well as the number of application cycles of PBa, has a positive effect on the bond strength, but without reaching initial values. Decontamination of the dentin surface by spraying or washing off after saliva contamination is preferable to further processing without pri-or cleansing.