Page 13 - Contributed Paper Session (CPS) - Volume 8

CPS2144 Laura Antonucci et al.
perform mini-invasive surgery and to use pre-established prostheses made
with CAD/CAM methods for an immediate and faithful functionalization of
virtual planning. The scientific literature shows that the flapless surgical
approach for implant placement has a long-term survival rate similar to the
open-flap conventional surgical techniques.
The aim of the study is to evaluate the accuracy of clinical results of dental
implant, positioned in total edentulous patients, with CAD/CAM surgical
guides, produced after 3D software planning. Through a specific software for
the evaluation of three-dimensional deviations it is possible to detect, in the
three spatial coordinates, the discrepancies between the project position and
the clinical position actually reached. Data available for this study do not allow
to consider traditional parametric technics because collecting data did not
follow a well-designed sampling procedure and distributional assumptions
are difficult to justify. In order to study the discrepancies between the
projected position and the actual position, we opted for nonparametric
technics in the field of permutation tests.
It is known that in many circumstances permutation tests perform better
than parametric tests by providing a valid statistical test with much weaker
assumptions (Arboretti et al., 2018, 2017; Pesarin et al., 2016).

2. Methodology
For the study 23 patients were - not randomly – selected after clinical
examination. All patients showed total maxillary edentulism and the need to
receive a full-arch immediate implant-prosthetic rehabilitation. Patients
underwent an implant surgical session, with the insertion of implants with an
external connection. Immediately after, there is the load of the prosthetic
device. Six months after loading, a control 3D cone beam computed
tomography (CBCT) radiographic examination was detected to evaluate the
deviations between the virtual project and the clinical position of the fixtures,
guided by the surgical template.
Differences for three spatial coordinates (X, Y, Z) between the virtual
planning implant position and the clinical actual position in the bone were
observed both at the apex and at the entry point of each implant. From a
statistical point of view, coordinates measured on the same implant are
dependent, whereas different implants can be assumed independent.
Data Dj = (Xj,Yj,Zj), j ∈ {apex, entry point} are differences given by
underlying paired observations pre and post-surgery. In fact, we may consider
observable variables as

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