Federico Mandelli

Evaluation of the accuracy of extraoral laboratory scanners with a single-tooth abutment model: A 3D analysis

PURPOSE The aim of this study was to compare the accuracy of different laboratory scanners using a calibrated coordinate measuring machine as reference. METHODS A sand blasted titanium reference model (RM) was scanned with an industrial 3D scanner in order to obtain a reference digital model (dRM) that was saved in the standard tessellation format (.stl). RM was scanned ten times with each one of the tested scanners (GC Europe Aadva, Zfx Evolution, 3Shape D640, 3Shape D700, NobilMetal Sinergia, EGS DScan3, Open Technologies Concept Scan Top) and all the scans were exported in .stl format for the comparison. All files were imported in a dedicated software (Geomagic Qualify 2013). Accuracy was evaluated calculating trueness and precision. RESULTS Trueness values (μm [95% confidence interval]) were: Aadva 7,7 [6,8-8,5]; Zfx Evolution 9,2 [8,6-9,8]; D640 18,1 [12,2-24,0]; D700 12,8 [12,4-13,3]; Sinergia 31,1 [26,3-35,9]; DScan3 15,6 [11,5-19,7]; Concept Scan Top 28,6 [25,6-31,6]. Differences between scanners were statistically significant (p<.0005). Precision values (μm [95% CI]) were: Aadva 4,0 [3,8-4,2]; Zfx Evolution 5,1 [4,4-5,9]; D640 12,7 [12,4-13,1]; D700 11,0 [10,7-11,3]; Sinergia 16,3 [15,0-17,5]; DScan3 9,5 [8,3-10,6]; Concept Scan Top 19,5 [19,1-19,8]. Differences between scanners were statistically significant (p<.0005). CONCLUSIONS The use a standardized scanning procedure fabricating a titanium reference model is useful to compare trueness and precision of different laboratory scanners; two laboratory scanners (Aadva, Zfx Evolution) were significantly better that other tested scanners.

Tilted Trans-Sinus Implants for the Treatment of Maxillary Atrophy: Case Series of 35 Consecutive Patients

PURPOSE To evaluate tilted trans-sinus implants for rehabilitation of the atrophic maxilla. MATERIALS AND METHODS A case series of 35 patients (32 consecutive edentulous and 3 partially edentulous patients) treated with trans-sinus dental implants is presented. Edentulous patients received 4 or 6 implants depending on anatomic conditions and a 12-unit final restoration; partially edentulous patients received 2 implants supporting a 3-unit partial fixed bridge. RESULTS Thirty-five patients (14 men, 21 women) underwent rehabilitation. Thirty-two patients with 190 implants placed received a full-arch fixed prosthesis supported by axial and trans-sinus tilted implants. Three patients each received 2 implants with a 3-unit fixed restoration. The mean age at surgery was 59.2 ± 9.5 years. The cumulative survival rate was calculated only for the full-arch fixed prosthesis group and was 98.42%. Crestal bone loss averaged 0.9 ± 0.4 and 0.8 ± 0.5 mm for the axial and tilted implants, respectively, at the 12-month evaluation. Biological complications at the implant level were 1 case of peri-implantitis and 3 cases of mucositis; no patient developed sinus infections. The prosthetic complications encountered were screw loosening in 17.5% of cases and chipping of the esthetic part in 30% of cases. These complications were easily resolved chairside and did not lead to prosthetic failure. CONCLUSIONS Trans-sinus tilted implants and sinus membrane distal displacement appear to be a viable minimally invasive alternative for the treatment of maxillary atrophy.

A novel technique to prevent the loss of graft material through the antrostomy after sinus surgery: technical note.

Maxillary sinus surgery has been shown to be a reliable procedure for increasing vertical bone height prior to implant placement. A variety of grafting materials have been proposed, with particulate bone substitutes showing similar clinical results to autogenous bone when rough surfaces implants are used. A barrier membrane is usually placed external to the grafted sinus, covering the antrostomy. In this technical report, the membrane is placed over the window and its borders gently tucked between the inner side of the bony wall and the graft material. This procedure stabilizes the membrane without tacks and prevents graft dislodgement through the antrostomy.

Implantology and otorhinolaryngology team-up to solve a complicated case.

Purpose: The aim of this article was to highlight the importance of the collaboration between implantologists and ear, nose, and throat (ENT) specialists to treat complex cases. Materials and Methods: A 46-year-old patient underwent a maxillary sinus elevation and implant placement 3 years before but because of a severe postop infection, the patient was treated with functional endoscopic sinus surgery (FESS) and lost the graft and the implants. Later, the patient consulted us and was referred to an ENT specialist because of sinus opacity. She underwent a second functional endoscopic sinus surgery (FESS); various ENT consultations and computer tomographies (CTs) were performed to assess sinus health. Results: After having confirmed with sinus health, sinus elevation, implant placement, and loading were performed with success. Conclusion: Collaboration between the implantologist and ENT specialist is necessary to distinguish between nonpathological membrane thickening because of the healing process after FESS and a pathological thickening due to infection.

Alveolar socket preservation with demineralised bovine bone mineral and a collagen matrix

Purpose The aim of the present study was to evaluate the healing of post-extraction sockets following alveolar ridge preservation clinically, radiologically, and histologically. Methods Overall, 7 extraction sockets in 7 patients were grafted with demineralised bovine bone mineral and covered with a porcine-derived non-crosslinked collagen matrix (CM). Soft tissue healing was clinically evaluated on the basis of a specific healing index. Horizontal and vertical ridge dimensional changes were assessed clinically and radiographically at baseline and 6 months after implant placement. For histological and histomorphometric analysis, bone biopsies were harvested from the augmented sites during implant surgery 6 months after the socket preservation procedure. Results Clinically, healing proceeded uneventfully in all the sockets. A trend towards reduced horizontal and vertical socket dimensions was observed from baseline to the final examination. The mean width and height of resorption were 1.21 mm (P=0.005) and 0.46 mm (P=0.004), respectively. Histologically, residual xenograft particles (31.97%±3.52%) were surrounded by either newly formed bone (16.02%±7.06%) or connective tissue (50.67%±8.42%) without fibrous encapsulation. The CM underwent a physiological substitution process in favour of well-vascularised collagen-rich connective tissue. Conclusions Socket preservation using demineralised bovine bone mineral in combination with CM provided stable dimensional changes of the alveolar ridge associated with good re-epithelialisation of the soft tissues during a 6-month healing period.

Improvement of a Digital Impression with Conventional Materials: Overcoming Intraoral Scanner Limitations

Intraoral digital impression is a viable alternative to conventional impression techniques and has been proven to be even more accurate than conventional materials. Nevertheless, there are cases in which the rheologic properties of conventional materials can be helpful. This article describes a method to overcome an insufficient sulcus-depth reading of intraoral scanners in challenging cases.

The Biological Properties of OGI Surfaces Positively Act on Osteogenic and Angiogenic Commitment of Mesenchymal Stem Cells

Osteogenesis process displays a fundamental role during dental implant osteointegration. In the present work, we studied the influence of Osteon Growth Induction (OGI) surface properties on the angiogenic and osteogenic behaviors of Mesenchymal Stem cells (MSC). MSC derived from dental pulp and HUVEC (Human Umbilical Vein Endothelial Cells) were grown in on OGI titanium surfaces, and cell proliferation and DNA synthesis were evaluated by MTT [3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide] test and DNA quantification. Gene expression has been performed in order to evaluate the presence of mRNA related to endothelial and osteogenesis markers. Moreover, morphological and biochemical analyses of osteogenesis commitments has been performed. On OGI surfaces, MSC and HUVEC are able to proliferate. Gene expression profiler confirms that MSC on OGI surfaces are able to express endothelial and osteogenic markers, and that these expression are higher compared the expression on control surfaces. In conclusion On OGI surfaces proliferation, expression and morphological analyses of angiogenesis-associated markers in MSC are promoted. This process induces an increasing on their osteogenesis commitment.

Ulteriori applicazioni degli scanner intraorali: duplicazione di corone e ponti provvisori funzionalizzati

Riassunto Obiettivi I restauri provvisori sono una parte essenziale delle terapie protesiche ma possono presentare alcuni problemi comuni, tra cui le fratture. Quando un provvisorio si rompe puo essere riparato, tuttavia non e piu possibile ottenere la resistenza meccanica iniziale. Scopo del presente lavoro e introdurre una nuova tecnica per realizzare la copia di una protesi provvisoria gia funzionalizzata. Materiali e metodi Una corona provvisoria e stata ribasata e rifinita. Appena prima della cementazione e stata acquisita, fuori del cavo orale, con uno scanner intraorale (3D Progress, MHT Srl, Verona). Un modello 3D della corona, completo della superficie sia interna sia esterna, e stato generato e inviato a un centro di fresaggio. Risultati E stata prodotta una copia della corona provvisoria fresandola con uno dei materiali disponibili sul mercato. Questa copia si e dimostrata clinicamente accettabile e ha richiesto solo alcuni lievi ritocchi occlusali. Conclusioni Le protesi prodotte con il flusso di lavoro descritto sono poco costose, richiedono meno tempo e sono piu resistenti rispetto a una lavorazione convenzionale alla poltrona. E possibile fresare protesi senza la necessita di ricorrere alle tecniche di Computer Aided Design (CAD) con i relativi costi.