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Purpose To systematically review in vitro and clinical studies comparing quantitatively the 3D accuracy (global implant deviations) of digital vs conventional implant impressions for partially and completely edentulous patients. Materials and methods Electronic and manual searches were conducted to identify in vitro and clinical studies, reporting on the 3D accuracy between digital and conventional implant impressions. Secondary outcomes were the effect of implant angulation, type of conventional impression technique, and type of intraoral scanner on the accuracy of implant impressions. Results The inclusion criteria were met by 9 in vitro studies and 1 clinical study reporting on completely edentulous impressions, while 6 in vitro and 2 clinical studies reported on partially edentulous impressions. Quantitative meta-analysis was performed for 5 completely edentulous and 6 partially edentulous studies. The studies exhibited high values for heterogeneity. A random effects model was conducted to estimate the effect size. Based on 5 in vitro studies on completely edentulous impressions, the mean 3D implant deviation between conventional and digital impressions was 8.20 µm (95% CI: -53.56, 37.15) and the digital impressions had nominally less deviation (p = 0.72). Based on 1 clinical and 5 in vitro studies on partially edentulous impressions, the mean 3D implant deviation between conventional and digital impressions was 52.31 µm (95% CI: 6.30, 98.33) and the conventional impressions had nominally less deviation (p = 0.03). Five in vitro and 2 clinical studies were not included in the quantitative analysis due to heterogeneity in the methodology. Implant angulation affected the accuracy in favor of the partially edentulous conventional impressions whereas the effect of different scanners was not statistically significant on the completely edentulous impressions (p = 0.82). Conclusions Digital scans appear to have comparable 3D accuracy with conventional implant impressions based mainly on in vitro studies. However, clinical trials are recommended to investigate the clinical accuracy of digital scans and digitally fabricated interim or prototype prostheses, before digital implant scans can be recommended for routine clinical use.

This article describes the case of a partially edentulous patient who had undergone template-guided implant placement and was treated using a triple digital scanning protocol that allowed for CAD/CAM prosthodontic rehabilitation in a complete digital workflow. At the impression appointment, the provisional implant-supported screw-retained prosthesis was digitally scanned both intraorally (first scan) and, after removal, extraorally (second scan). After the second scan, scan bodies were placed intraorally and an implant-level digital impression was taken (third scan). The three standard tessellation language (STL) files derived from the three digital scans were imported in a CAD software and superimposed into one file that contained all of the information from the implant 3D position, prosthesis contours, and transmucosal part of the peri-implant soft tissues. The superimposition of the three STL files led to one master file to serve as a blueprint for the definitive prosthesis. The definitive monolithic zirconia prosthesis was CAM copy-milled, externally stained, and inserted. The patient was satisfied with both the esthetic and functional outcome and the minimally invasive, time-efficient, two-visit restorative protocol. In summary, this case report illustrates a technique for a complete digital workflow in an implant rehabilitation for the replacement of multiple missing teeth in the esthetic zone in two visits.

UNLABELLED Implants nowadays have conquered the majority of prosthetic restorations in the everyday clinical practice. As a result there has been a tendency among many clinicians to believe that implant therapy is the best solution in every clinical case, even if extraction of natural tooth with questionable prognosis is necessary. The value of natural teeth has been recently reconsidered. An implant not placed under ideal circumstances, may lead to a compromised result especially in the anterior maxillary region. Conversely natural teeth, even in a compromised clinical condition, maintain proprioception and can be adapted to the stresses of functional loading. The most demanding task in daily clinical practice is the treatment plan. The role of the clinician is more complicated for the anterior teeth where the patient's expectations and the esthetic criteria complicate the objective way of thinking. Therefore, a frequent dilemma in dental practice is whether to maintain an anterior tooth with a questionable prognosis or to extract it and replace it with an implant. The aim of this article is to approach the dilemma of extraction or maintenance of anterior teeth with a questionable prognosis through a series of clinical cases focusing on the factors that should be taken under consideration. CLINICAL SIGNIFICANCE Dental implants offer increased possibilities in the restoration of the anterior maxillary teeth. In specific clinical cases however a satisfying clinical result can be achieved by maintaining the existing natural teeth even if they have a questionable prognosis and a more complicated treatment plan may be needed. (J Esthet Restor Dent, 2016).

Implants nowadays have conquered the majority of prosthetic restorations in the everyday clinical practice. As a result there has been a tendency among many clinicians to believe that implant therapy is the best solution in every clinical case, even if extraction of natural tooth with questionable prognosis is necessary. The value of natural teeth has been recently reconsidered. An implant not placed under ideal circumstances, may lead to a compromised result especially in the anterior maxillary region. Conversely natural teeth, even in a compromised clinical condition, maintain proprioception and can be adapted to the stresses of functional loading. The most demanding task in daily clinical practice is the treatment plan. The role of the clinician is more complicated for the anterior teeth where the patient's expectations and the esthetic criteria complicate the objective way of thinking. Therefore, a frequent dilemma in dental practice is whether to maintain an anterior tooth with a questionable prognosis or to extract it and replace it with an implant. The aim of this article is to approach the dilemma of extraction or maintenance of anterior teeth with a questionable prognosis through a series of clinical cases focusing on the factors that should be taken under consideration.Dental implants offer increased possibilities in the restoration of the anterior maxillary teeth. In specific clinical cases however a satisfying clinical result can be achieved by maintaining the existing natural teeth even if they have a questionable prognosis and a more complicated treatment plan may be needed. (J Esthet Restor Dent, 2016).