Luigi V. Stefanelli, DDS, PhD/Bradley S. DeGroot, DDS, MS/David I. Lipton, DDS, MS/George A. Mandelaris, DDS, MS: Purpose: To evaluate the in vivo accuracy of dental implants placed using a dynamic computer-aided dental implant (CAI) navigation system. The impact of various factors on accuracy was also analyzed. Materials and Methods: A retrospective, in vivo study was performed during the period of October 2015 to December 2017. Data were obtained on all implants placed during this time frame. A chart review was conducted to identify the type of flap, number of implants placed, number of patients treated, and factors related to the description of edentulism (partial or complete). To evaluate accuracy outcomes, the preoperative cone beam computed tomography (CBCT) plan was volumetrically registered to a postimplant placement CBCT scan. Deviations between the planned and placed implant positions were analyzed. Data were statistically analyzed to factors that may affect the accuracy during usage. Results: Data were obtained on 231 implants placed in healed ridges using a flapless or minimal flap approach under dynamic guidance by a single surgeon. In the 89 arches operated on, 28 (125 implants) were fully edentulous. For all implants, the mean (SD) discrepancies were: 0.71 (0.40) mm for entry point (lateral) and 1.00 (0.49) mm at the apex (3D). The mean angle discrepancy was 2.26 degrees (1.62 degrees) from actual vs planned implant positions. The accuracy measurements for partially edentulous patients using a thermoplastic stent attachment and for fully edentulous patients using a mini-implant?based attachment were nearly identical. No significant accuracy differences were found between implant position within the different sextants. Guided insertion of the implant itself reduced angular and apex location deviations. The accuracy of implant placement improved during the study period, with the mean entry point and apex deviation as well as overall angle discrepancy measured for the last 50 implants being better (0.59 mm, 0.85 mm, and 1.98 degrees, respectively) when compared with the first 50 implants (0.94 mm, 1.19 mm, and 3.48 degrees, respectively). Conclusion: Dynamic surgical navigation is an accurate method for executing CBCT-based computer-aided implant surgery. In addition, an increased experience level of the surgeon with dynamic navigation appears to improve accuracy outcomes.

Maxillary bone losses often require additional regenerative procedures: as a supplement to the procedures of tissue regeneration, a platelet concentrate called PRF (Platelet Rich Fibrin) was tested for the first time in France by Dr. Choukroun. Aim of the present study is to investigate, clinically and histologically, the potential use of PRF, associated with deproteinized bovine bone (Bio-Oss), as grafting materials in pre-implantology sinus grafting of severe maxillary atrophy, in comparison with a control group, in which only deproteinized bovine bone (Bio-Oss) was used as reconstructive material. 60 patients were recruited using the cluster-sampling method; inclusion criteria were maxillary atrophy with residual ridge < 5mm. The major atrophies in selected patients involved sinus-lift, with a second-look reopening for the implant insertion phase. The used grafting materials were: a) Bio-Oss and b) amorphous and membranous PRF together with Bio-Oss. We performed all operations by means of piezosurgery in order to reduce trauma and to optimize the design of the operculum on the cortical bone. The reopening of the surgical area was scheduled at 3 different times. 72 sinus lifts were performed with subsequent implants insertions.We want to underline how the histological results proved that the samples collected after 106 days (Early protocol) with the adding of PRF were constituted by lamellar bone tissue with an interposed stroma that appeared relaxed and richly vascularized. The use of PRF and piezosurgery reduced the healing time, compared to the 150 days described in literature, favoring optimal bone regeneration. At 106 days, it is already possible to achieve good primary stability of endosseous implants, though lacking of functional loading.

Michele Cassetta, DDS, PhD/Matteo Giansanti, DDS/Alfonso Di Mambro, DDS/Luigi Vito Stefanelli, DDS, Deng: Purpose: The aim of this study was to evaluate the accuracy of implants inserted using a mucosa-supported stereolithographic surgical guide and to determine the influence of surgical management of the guide (fixed or unfixed), arch (maxilla or mandible), and smoking habit (normal or hyperplastic mucosa) on accuracy. Materials and Methods: In completely edentulous subjects, preoperative computed tomography (CT) was performed, and the images were used to plan implant positions. After the implants were placed, CT was performed again, and the presurgical and postoperative images were compared. With computer software, the jaw contours from the two CT scans were matched and the deviations between the planned and actual implant positions were evaluated. Surgical technique, arch, and smoking habit were examined as independent variables, and their influence on accuracy was evaluated with a t test. Results: Twenty-eight surgical guides (225 implants) were included in this study. Deviations between planned and actual positions were seen in the global coronal (mean ? SD: 1.68 ? 0.6 mm), global apical (2.19 ? 0.83 mm), and angular (4.67 ? 2.68 degrees) dimensions. Fixation of surgical guides (fixed: 4.09 degrees; not fixed: 5.62 degrees) and use of the guide in the maxilla (4.36 degrees; mandible: 5.46 degrees) resulted in statistically significantly less angular deviation (ie, better accuracy). Nonsmoking patients showed statistically significantly better accuracy in global coronal (nonsmokers: 1.54 mm; smokers: 1.83 mm) and global apical (nonsmokers: 2.08 mm; smokers: 2.27 mm) deviations. Conclusion: The greater supporting surface of the maxilla and fixation of the surgical guide improved the accuracy of the guides. The reduced mucosa thickness in nonsmokers decreased global coronal and global apical deviation.