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HANGZHOU, China: High accuracy in the planning and execution of implant procedures is important in securing a high success rate. In order to achieve functional and aesthetic results, many clinicians use surgical templates to guide placement during surgery. In measuring the effect of surgical templates on the accuracy of implant placement, a Chinese study recently found that actual and planned implant positions varied significantly.
According to the researchers, errors in computer-guided implant surgery are caused by either the operator during surgery or the surgical template preoperatively. In order to evaluate the effect of surgical templates on the accuracy of implant placement, jaws from 16 patients were scanned using cone beam computed tomography (CBCT). Fifty-three implants were planned in a virtual 3-D environment, of which 35 were placed in the mandible and 18 in the maxilla.
For the analyses, a stereolithographic surgical template was created. The template was then fitted on a plaster model and both were scanned with a CBCT device. The images obtained were matched to images of the virtual planned implant position. The actual implant position was acquired from the registration position of the surgical template.
In comparing the data, the researchers found significant deviation between actual and planned positions caused by the surgical template. The mean central deviation at the hex and apex was 0.456 mm and 0.515 mm, respectively. The mean horizontal deviation at the hex was 0.193 mm and at the apex was 0.277 mm. The mean vertical deviation at the hex was 0.388 mm and at the apex was 0.390 mm. The mean angular deviation was 0.621°.
The results of the study indicate that clinicians should not rely solely on the safety of surgical templates in seeking to avoid critical anatomical structures.
The study, titled “Impact of surgical template on the accuracy of implant placement”, was published online on 30 November in the Journal of Prosthodontics. It was conducted by researchers from the Zhejiang University of Technology in collaboration with the Zhejiang People’s Hospital, both located in Hangzhou in China.
From http://www.dental-tribune.com
