Reproducibility of volumetric measurements on maxillary sinuses.

Although computer assisted volumetric quantification of human maxillary sinuses is commonly used to measure volumetric changes during life, reliability data for this procedure are lacking. The objective of this retrospective study is to test a semi-automatic virtual volumetric analysis technique on 36 CT scans of human maxillary sinuses. Three examiners with different clinical experience performed all measurements in three replicates. As principle of proof, the technique was examined on 12 phantoms with known volumes. The validation of the method revealed that the mean relative error was 0.364%. For the retrospective volumetric measurements from maxillary sinuses the intra- and inter-examiner agreement was quantified using appropriate intraclass correlation coefficients (ICC 1,k and ICC 2,k) and the Bland-Altman analysis. ICC values ranging from 0.997 to 0.999 indicate almost perfect agreement for intra- and inter-examiner data. The Bland-Altman analysis demonstrated good intra- as well as inter-examiner agreement for the two proficient examiners and a lack of agreement for the untrained examiner. It can be concluded that this measurement procedure using CT scans could be strongly recommended for clinical application to determine the volume of human maxillary sinuses reliably.

All-ceramic immediate restoration of one-piece zirconium dioxide implants.

The multipiece nature of different implant systems is problematic for a number of reasons. The greatest challenge is bacterial colonization of the implant and of the surrounding tissue, because of the implant/abutment and abutment/crown interfaces, as well as the micromovements of the individual components of the implant. A possibility of eliminating microgaps between the individual components of the implant on the one hand and avoiding micromovements on the other is described in this paper.