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PhD, University of Lisbon School of Dental Medicine; Master, University of Lisbon School of Dental Medicine Postgraduate Certificate in Periodontology and Implant Dentistry from New York University College of Dentistry, New York - USA Assistant Professor and Coordinator of the Oral Surgery and Implant Dentistry Pos-graduate Program at University of Lisbon, School of Dental Medicine; President of the Dennis Tarnow Alumni Association ITI Fellow (International Team for Implantology) Associate Editor of the International Journal of Prosthodontics amd of the magazine of Sociedade Portuguesa de Estomatologia e Medicina Dentária Author and co-author of several conferences, communications, posters and other national and international publications. Private Pratice - Instituto Implantologia Lisbon, Portugal
Purpose: To compare trueness and precision between conventional and digital facial measurements and to evaluate the accuracy of different superimposition techniques for facial scans.
Materials and Methods: Twenty volunteers were recruited. Predetermined facial landmarks were marked with a black marker, and the interlandmark distances were measured manually with a conventional caliper and digitally with Geomagic software. Two consecutive facial scans were performed and then superimposed, using as best-fit reference the full face, the face without the eyes, and the bone-supported areas (eg, forehead and zygomatic areas) in order to assess root mean square (RMS) differences. Trueness and precision were evaluated and compared between the conventional and digital techniques. Mann-Whitney U and Kruskal-Wallis post hoc tests were used. The significance level was established as α = .05.
Results: Trueness between conventional and digital measurements was 1,151.75 ± 1,265.52 μm (3.04% ± 4.82%), and precision was 322.31 ± 300.54 μm (0.93% ± 1.10%). Global mean RMS values for each superimposition technique were 334.15 ± 172.07 for the full face, 339.57 ± 173.13 for the face without the eyes, and 385.65 ± 182.29 for the bone-supported areas, with the latter presenting statistically significant differences compared to the other two.
Conclusion: Although statistically significant differences were detected in facial measurements, they were below the clinically detectable threshold. Superimposition with the full face and the face without the eyes area presented smaller discrepancies than with the bone-supported areas, with higher discrepancies in the lower third of the face.
DOI: 10.3290/j.qi.a39508, PubMed-ID: 29234740Seiten: 103-111, Sprache: EnglischMartins, Jorge N. R. / Marques, Duarte / Francisco, Helena / Caramês, João
Objective: The aim of this study was to investigate in vivo, using cone beam computed tomography (CBCT), the differences between genders regarding the number of roots and root canal morphology.
Method and Materials: An existing CBCT scan database was accessed and the scans were divided in two groups according to gender. Tooth inclusion and exclusion criteria were applied. The examined teeth were classified according to the number of roots, and the root canal system was classified according to Vertucci classification. Z-test for independent groups was used to detect differences between groups.
Results: In total, 12,325 teeth (4,597 from males and 7,728 from females) from 670 patients were analyzed. Females presented a lower number of roots per tooth in all groups of teeth, except for mandibular canine, the difference being statistically significant in the maxillary first premolar and both maxillary and mandibular second molars. Vertucci Type I configuration had a higher or equal prevalence in nine of the eleven groups of maxillary roots in females, with significance in both maxillary premolars. The same configuration was higher in females in five of the nine groups of mandibular roots, with significance in mandibular central incisor and first premolar. Eight of the nine root groups (maxillary and mandibular roots combined) that presented three-root canal system configurations, had a higher prevalence of that anatomy in males.
Conclusion: Few differences were found between genders. It was possible to detect a lower number of roots per tooth and a higher number of Vertucci Type I configurations in females. The three-root canal system configurations were more common in males.
Schlagwörter: anatomy, cone beam computed tomography, gender, morphology, root canal
The International Journal of Oral & Maxillofacial Implants, 6/2016
DOI: 10.11607/jomi.4675, PubMed-ID: 27861668Seiten: 1407-1414, Sprache: EnglischCaramês, João Manuel Mendez / Mata, António Duarte Sola Pereira da / Marques, Duarte Nuno da Silva / Francisco, Helena Cristina de Oliveira
Purpose: This was a retrospective cohort study designed to evaluate the clinical performance of ceramicveneered zirconia frameworks.
Materials and Methods: Patients were recruited according to defined inclusion criteria. All patients were checked every 4 months from the time of definitive rehabilitation. At the end of 2013, all patients were rescheduled and rechecked for study purposes. The restorative procedures assessment was performed by previously established methods. The primary outcomes were the survival and success rates of the prosthesis. Descriptive statistics were used for the patient's demographics, implant distribution, and occurrence of complications. To study the survival and success of the prostheses, a Cox Regression analysis was used with a model constructed in a forward conditional stepwise mode. Predictive variables were included in the model, and adjusted survival curves were obtained for each outcome.
Results: From 2008 to 2013, 75 patients were rehabilitated with 92 implant-supported, screw-retained, full-arch ceramic-veneered zirconia framework rehabilitations. The range of follow-up was between 6 months and 5 years. From the 92 full implant-supported screw-retained full-arch rehabilitations, Cox regression analysis indicated that within a 5-year time frame, the probability of framework fracture, major chipping, minor chipping, or any of the former combined to occur was 17.6%, 46.5%, 69.2%, and 90.5%, respectively.
Conclusion: Results suggest zirconia as a suitable material for framework structure in implant-supported, full-arch rehabilitations. However, it experiences a high incidence of technical complications, mainly due to ceramic chipping. Further clinical studies should aim to ascertain the effects of clinical features and manufacturing procedures on the survival rates of these prostheses.
Schlagwörter: clinical research, computer-aided design, dental prosthesis, dental prosthesis design, implant supported, retrospective studies, zirconium oxide