Marta Revilla Leon M.S.D.

Piedra-Cascón, W., Meyer, M.J., Methani, M.M. and Revilla-León, M. (2020). “Accuracy (trueness and precision) of a dual-structured light facial scanner and interexaminer reliability.” J Prosthet Dent 124(5): 567-574

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STATEMENT OF PROBLEM: Digital waxing procedures should be guided by facial references to improve the esthetic outcome of a restoration. The development of facial scanners has allowed the digitalization of the extraoral soft tissues of the patient’s face. However, the reliability of facial digitizers is questionable. PURPOSE: The purpose of this study was to evaluate the accuracy (trueness and precision) of extraoral 3D facial reconstructions performed by using a dual-structured light facial scanner and to measure the interexaminer variability. MATERIAL AND METHODS: Ten participants were included. Six soft-tissue landmarks were determined on each participant, specifically reference (Ref), glabella (Gb), subnasal (Sn), menton (Me), chelion right (ChR), and chelion left (ChL). Interlandmark distances Ref-Sn, Sn-Gb, Ref-Gb, Sn-Me, and ChR-ChL (intercommissural) were measured by 2 different operators by using 2 different methods: directly on the participant’ face (manual group) and digitally (digital group) on the 3D facial reconstruction of the participant (n=20). For the manual group, interlandmark measurements were made by using digital calipers. For the digital group, 10 three-dimensional facial reconstructions were acquired for each participant by using a dual-structured light facial scanner (Face Camera Pro Bellus; Bellus3D). Interlandmark measurements were made by using an open-source software program (Meshlab; Meshlab). Both operators were used to note 10 measurements for each manual and digital interlandmark distance per participant. The intraclass correlation coefficient between the 2 operators was calculated. The Shapiro-Wilk test revealed that the data were not normally distributed. The data were analyzed by using the Mann-Whitney U test. RESULTS: Significant differences were found between manual and digital interlandmark measurements in all participants. The mean value of the manual and digital group discrepancy was 0.91 ±0.32 mm. The dual-structured light facial scanner tested obtained a trueness mean value of 0.91 mm and a precision mean value of 0.32 mm. Trueness values were always higher than precision mean values, indicating that precision was relatively high. The intraclass correlation coefficient between the 2 operators was 0.99. CONCLUSIONS: The facial digitizing procedure evaluated produced clinically acceptable outcomes for virtual treatment planning. The interexaminer reliability between the 2 operators was rated as excellent, suggesting that the type of facial landmark used in this study provides reproducible results among different examiners.

Ashtiani, R.E., Tehrani, S., Revilla-León, M. and Zandinejad, A. (2020). “Reducing the Risk of COVID-19 Transmission in Dental Offices: A Review.” J Prosthodont Sep 15. [Epub ahead of print.].

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The COVID-19 epidemic has become a major public health challenge around the world. According to the World Health Organization (WHO), as of August 2020 there are more than 833,556 dead and over 24,587,513 people infected around the world. This pandemic has adversely affected many professions around the globe, including dentistry. COVID-19, caused by the Corona virus family, is transmitted mainly by direct contact with an infected person or through the spread of aerosol and droplets. Dentistry by nature is considered to be one of the most vulnerable professions with regards to the high risk of transmission between the dentist, dental team, and patients; therefore, a protocol for infection control and the prevention and spreading of the COVID-19 virus in dental settings is urgently needed. This article reviews essential knowledge about this virus and its transmission and recommends preventive methods based on existing scientific research and recommendations to prevent the spread of this virus in dental offices and clinics.

Revilla-León, M., Methani, M.M. and Özcan, M. (2020). “Impact of the ambient light illuminance conditions on the shade matching capabilities of an intraoral scanner.” J Esthet Restor Dent Sep 21. [Epub ahead of print.].

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PURPOSE: To compare the shade matching capabilities between an intraoral scanner (IOS) and a spectrophotometer under different ambient light illuminance conditions. MATERIAL AND METHODS: The shade of three teeth of a patient was obtained using an IOS (IOS group) (TRIOS 3; 3Shape) and a spectrophotometer (DS group) (EasyShade V; Vita Zahnfabrik) at 4 ambient illuminances: 10000-, 1000-, 500-, and 0-lx. Ten shade measurements were documented using Vita Classical and 3D-Master guides per tooth at each lighting condition. Data was analyzed using the Kruskal-Wallis and Mann Whitney U tests (α = .05). RESULTS: Significant shade discrepancies were obtained between the groups in different lighting conditions (P < .05). The IOS group presented significant shade discrepancies in different lighting conditions when evaluated using either shade guide, with lower variation under the 0-lx condition. However, the DS group did not present significant shade discrepancies among the different lighting conditions with either shade guide, except for the maxillary lateral incisor measured under 10 000-lx condition using the 3D-Master guide. CONCLUSIONS: Lighting conditions influenced the shade matching competency of an IOS. The IOS tested obtained high variation in the different lighting conditions evaluated and provided a lower shade value than the spectrophotometer. The spectrophotometer revealed high consistency amongst the various lighting conditions evaluated. CLINICAL IMPLICATIONS: Ambient light illuminance conditions can impact the shade matching capabilities of IOSs. The results of this investigation suggest the use of a supplementary instrumental method for assessment of tooth shade.

Piedra-Cascón, W., Sadeghpour, M., Att, W. and Revilla-León, M. (2020). “A vat-polymerized 3-dimensionally printed dual-material occlusal device: A dental technique.” J Prosthet Dent Sep 17;S0022-3913(20)30438-8. [Epub ahead of print.].

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A technique to additively manufacture an occlusal device by using a completely digital workflow is described. Using a computer-aided design program, information captured with an intraoral scanner was used to additively manufacture a dual-material occlusal device by using a vat-polymerization printer. This technique allows for the combination of 2 different materials, resulting in an occlusal device with a resilient intaglio and a hard resin exterior surface. Advantages of the resulting occlusal device compared with a single-material device include improved patient acceptance and comfort, better fit, and minimal adjustments to ensure fit.

Pérez-Giugovaz, M.G., Park, S.H. and Revilla-León, M. (2020). “Three-dimensional virtual representation by superimposing facial and intraoral digital scans with an additively manufactured intraoral scan body.” J Prosthet Dent Sep 24;S0022-3913(20)30439-X. [Epub ahead of print.].

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A technique to merge facial and intraoral digital scans guided by an additively manufactured intraoral scan body is described. The technique facilitates facially driven treatment planning of restorative procedures in situations where a cone beam computed tomography scan is not indicated. Furthermore, the intraoral scan body can be customized to the size of the patient’s arch to improve patient comfort and simplify the digitalization procedures.