The effect of number of telescopic PEEK crowns on unilateral free-end saddle supporting structures. A strain gauge stress analysis study

The aim of this in vitro study was to evaluate the strain induced on the last natural abutment and the unilateral free end saddle supporting area in case of using two splinted telescopes VS using single telescope with removable partial dentures. Costruction of two epoxy resin casts was done these casts were of Kennedy class II lower with the last standing tooth is the first premolar, simulation of periodontal ligaments and alveolar mucosa was done with rubber, For the first cast PEEK telescopic crowns were constructed on first premolar only while for the second cast it was done on both canine and first premolar. Then chrome cobalt removable partial dentures were done where the secondary coping are attached to its fitting surface. Using two strain gauges fixed on each cast one on the free end saddle area and the other was distal to the first premolar. Using loading machine and strain meter, load was applied on two sites the second premolar and the first molar .collected data were statistically analyzed .It showed significant difference between the two casts, where micro strains were higher in case of using only one telescope where it was less with two telescope .also micro strains were less on the residual ridge than on the distal side of the first premolar in both casts. In conclusion, different designs of RPDs will have different effects on abutments and residual ridges but many studies suggested using telescopic crowns as an appropriate treatment options for such cases as it ensures maximally favorable masticatory force transmission, which always takes place axial to the abutments. This treatment modality can lead to predictable long-term treatment outcomes. The limitations in this study were that it was carried out in vitro without considering the variation in clinical situations of different patients. Thus future clinical trials should be carried out to confirm any concluded results.