IADR Abstract Archives
Effectiveness of Retraction Techniques for Dental Impressions - Clinical Trial Results
Objectives: Dental impressions need an adequate soft-tissue management with retraction materials and techniques in order to achieve the required accuracy e.g. for making fixed partial dentures. We asked probands to participate in a clinical trial analyzing the depth and width of the sulcus representation after using either the double cord technique or a kaolin-based paste. We also examined a possibly persisting gingival recession.
Methods: Forty probands gave informed consent. After making the baseline impression, we asked them to refrain from tooth brushing for up to 14 days to induce experimental gingivitis. We than made the intervention impressions after using either a kaolin-based aluminum chloride containing paste (3M Astringent Retraction Paste, 3M Oral Care) or cords impregnated with the same astringent (RoekoRetracto, Coltène/Whaledent).
The clinical investigator put the retraction materials into the palatal sulci of the upper premolars. The laboratory team made gypsum master models, which were digitized (digiSCAN, AmannGirrbach).The analysis team measured the achieved depth and width of the sulci using reverse engineering software (Surfacer10.6 and geomagic studio/qualify 9). Thereafter, we made control impressions every three months to assess any gingival recession.
In addition to descriptive statistics, we used the one-sample t-test and univariate analysis of variance (IBM SPSSS 24.0)
Results: The mean sulcus width was 0.6mm (SD 0.1; maximum 0.8mm) for both retraction techniques. The mean sulcus depth using the cord technique was 0.8mm (SD 0.2; max. 1.1mm) and using the paste 0.7mm (SD 0.15; max. 1.0mm). Only the maximum sulcus depth showed a significant difference between cord and paste application (p=0.011).
Conclusions: With both methods, we achieved a clinically suitable sulcus representation in probands with mild artificial gingivitis. Both materials initially cause gingival recession but neither technique resulted in persisting gingival recession after one year under observation. This requires a non-damaging application of the retraction techniques.
Methods: Forty probands gave informed consent. After making the baseline impression, we asked them to refrain from tooth brushing for up to 14 days to induce experimental gingivitis. We than made the intervention impressions after using either a kaolin-based aluminum chloride containing paste (3M Astringent Retraction Paste, 3M Oral Care) or cords impregnated with the same astringent (RoekoRetracto, Coltène/Whaledent).
The clinical investigator put the retraction materials into the palatal sulci of the upper premolars. The laboratory team made gypsum master models, which were digitized (digiSCAN, AmannGirrbach).The analysis team measured the achieved depth and width of the sulci using reverse engineering software (Surfacer10.6 and geomagic studio/qualify 9). Thereafter, we made control impressions every three months to assess any gingival recession.
In addition to descriptive statistics, we used the one-sample t-test and univariate analysis of variance (IBM SPSSS 24.0)
Results: The mean sulcus width was 0.6mm (SD 0.1; maximum 0.8mm) for both retraction techniques. The mean sulcus depth using the cord technique was 0.8mm (SD 0.2; max. 1.1mm) and using the paste 0.7mm (SD 0.15; max. 1.0mm). Only the maximum sulcus depth showed a significant difference between cord and paste application (p=0.011).
Conclusions: With both methods, we achieved a clinically suitable sulcus representation in probands with mild artificial gingivitis. Both materials initially cause gingival recession but neither technique resulted in persisting gingival recession after one year under observation. This requires a non-damaging application of the retraction techniques.