Compressibility of two polyvinyl siloxane interocclusal record materials and its effect on mounted cast relationships

Statement of problem. Addition silicones (polyvinyl siloxanes) are universa lly accepted as accurate and stable impression materials. They have also ga ined popularity as interocclusal record materials. However, it has not been defined. if it is possible to more with polyvinyl siloxanes without changi ng the recorded maxillomandibular relations. Purpose. This study examined the compressibility of 2 addition silicones as interocclusal record materials, analyzing the changes of maxillomandibular relations at the condyle region when different compressive forces are used to stabilize articulated casts. Material and methods. Sixteen interocclusal records, obtained from the same patient (8 of each polyvinyl siloxane, Blu-Mousse, Fast Set), were interpo sed between the patient casts ill a new measuring system obtaining 48 curve s of load versus maxillomandibular positional changes in 3 axes (x, y, z). These curves were compared with curves obtained with the casts in maximum i ntercuspation without interocclusal records (reference curves). Analysis of variance was used to compare maxillomandibular positional changes among th e 3 groups (n = 48 each): Blu-Mousse, Fast Set, and control group or maximu m intercuspation without interocclusal record. Results. There mns no significant change in maxillomandibular relations whe n forces up to 1 kgf were: applied to stabilize the casts related by means of Blu-Mousse and Fast Set addition silicone interocclusal records. Conclusion. It is possible to use these polyvinyl siloxanes as interocclusa l record materials without changing the recorded maxillomandibular relation s.