IADR Abstract Archives
Effect of Multiple Use of Impression Copings on Implant Cast Accuracy
Objectives: The objective of this study was to assess the effect of multiple use of Straumann implant impression copings on the accuracy of partially edentulous implant casts at bone level. The null hypothesis tested was there would be no significant difference in the accuracy of casts in terms of linear (in all dimensions i.e x-, y-, z-axes) and 3D (3-dimensional) discrepancies in comparision to the master model when implant impression copings are reused to produce up to ten impressions and casts
Methods: Ten direct polyether impressions were made of a partially edentulous mandibular acrylic master model (Straumann,Australia) fitted with two bone-level internal connection implants (StraumannRC bone level) in the positions of the right first premolar and first molar to produce ten dental stone casts The same set of impression copings (StraumannRC impression post) were sterilised and reused for each of the ten impressions. The stone casts along with the master model were digitised using scanbodies and laboratory scanner. Measurements were made on the digitised casts using computer software and discrepancies calculated in the x-,,y- and z-axes between the sample casts and the master model. The overall 3D(R) differences were also measured and the data statistically analysed using paired t-tests (α=0.05).
Results: The absolute discrepancies for the casts(1-10) in comparison to the master model ranged from 10-70µm in x-axis, 10-70µm in y-axis, 20-60µm in z-axis, and 47-107µm for R No significant differences were noted between the casts produced by impression coping reuse in all the linear dimensions (p>0.05), except in the y-axis for cast 6 (P<0.05). However, statistical analysis of R (3D) values revealed that casts 2, 4 and 8 were significantly different compared to cast 1(P<0.05)
Conclusions: Reuse of Straumann RC impression copings upto ten times does not seem to affect the accuracy of partially edentulous multi-implant dental casts.
Methods: Ten direct polyether impressions were made of a partially edentulous mandibular acrylic master model (Straumann,Australia) fitted with two bone-level internal connection implants (StraumannRC bone level) in the positions of the right first premolar and first molar to produce ten dental stone casts The same set of impression copings (StraumannRC impression post) were sterilised and reused for each of the ten impressions. The stone casts along with the master model were digitised using scanbodies and laboratory scanner. Measurements were made on the digitised casts using computer software and discrepancies calculated in the x-,,y- and z-axes between the sample casts and the master model. The overall 3D(R) differences were also measured and the data statistically analysed using paired t-tests (α=0.05).
Results: The absolute discrepancies for the casts(1-10) in comparison to the master model ranged from 10-70µm in x-axis, 10-70µm in y-axis, 20-60µm in z-axis, and 47-107µm for R No significant differences were noted between the casts produced by impression coping reuse in all the linear dimensions (p>0.05), except in the y-axis for cast 6 (P<0.05). However, statistical analysis of R (3D) values revealed that casts 2, 4 and 8 were significantly different compared to cast 1(P<0.05)
Conclusions: Reuse of Straumann RC impression copings upto ten times does not seem to affect the accuracy of partially edentulous multi-implant dental casts.