FREE HAND VERSUS PARTIAL LIMITING DESIGN COMPUTER GUIDED SURGICAL STENT (VITRO STUDY)

Aim of the study: Was to compare the accuracy of two different surgical techniques; free hand and partial limiting, regarding the accuracy of implant position.
Materials and methods: Four edentulous dummy mandible simulating human edentulous mandible were used (the model material duplicates type II~III hardness). A surgical stent was fabricated. The surgical stent was secured on the first and second mandibles and all the implants were placed using the partial limit technique; where the initial drill was used first using the stent. The subsequent drills were used free hand. The same stent was placed on the other two mandibles where the position of the implants was delineated using a marker, then the implants were placed free hand. The angles between the long axis of preplanned and real implants were recorded from both the preoperative implant plan & the post-operative implant representations on the resliced CBCT image & were compared to each other in degrees. The linear deviation of the post-operative placement was recorded in mm in coronal & apical positions from the pre-planned implants in both Mesio-distal & Bucco-lingual aspects, also the vertical linear deviation (deviation in depth), was recorded apically, taking the pre-operative implant plan as the reference by the aid of the software matching function.
Results : The data was collected and statistically analyzed. The mean angular deviation for group A the free hand was 3.71 ± 2.58 degree while that for group B partial limiting was 1.72 ± 1.67 degree, this difference was statistically significant P0.05. There was statistical significance difference between both groups concerning the angular deviation, Bucco lingual deviation and Mesio distal deviation, while apical deviation was not significantly different.
Conclusion: Partial limiting surgical stent is more precise than free hand surgical technique concerning the angular deviation, Bucco lingual deviation and Mesio distal deviation. There is no statistical significant difference concerning apical position.