How does an error in positioning the template affect the accuracy of implants inserted using a single fixed mucosa-supported stereolithographic surgical guide?

Computer-aided implantology using a single fixed stereolithographic surgical guide involves a sequence of diagnostic and therapeutic events, and errors can creep in at different stages. Taken together, these can be termed the ‘total error’. A positioning of the surgical guide on the support surface different to that of the diagnostic template may generate an error that reoccurs with all the implants inserted, and this error can be termed the ‘guide positioning error’. The aim of the present study was to measure the deviation between the planned and inserted implants due to this guide positioning error, to evaluate if this error was statistically significant, and concurrently, to assess the influence of the type of arch (upper vs lower jaw) and mucosal thickness on the guide positioning error. Twenty-four subjects were treated and 172 implants inserted. Preoperative and postoperative computed tomography images were compared using Mimics software to determine the total error and guide positioning error. Quantitative data were described; the t-test and Pearson correlation coefficient were used. The guide positioning error was found to affect the accuracy, but was statistically significant only for global coronal deviation (P = 0.038). Arch of support and mucosa thickness did not affect the guide positioning error.