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INTRODUCTION: Three-dimensional (3D)-printing technology can provide customizable simulations, but its effects on patient care quality have not been well studied. This study aimed to assess the impact of practicing with patient-specific 3D-printed teeth models on the quality of patients' dental preparations performed by students transitioning to clinical training. Accordingly, the quality of posterior crown preparations was evaluated by objectively analyzing digital scans and grades in two groups: the study group, which practiced beforehand with patient-specific 3D-printed teeth models, and the control group, which did not practice with these models. METHODS: All 78 fourth-year dental students who had just finished their fixed prosthodontics course at the simulation laboratory with training on phantom heads and without previous clinical experience in crown preparations were invited to participate in the study. Sixty-eight agreed to take part and were randomly divided into a study group that practiced crown preparations on 3D-printed models of their own patient's teeth and a control group that did not practice with 3D-printed models and started their clinical work straightforwardly after simulation training. Students completed validated perception questionnaires on self-confidence and clinical skills before and after the protocol, which were compared using a chi-squared test. Crown preparations performed on 3D-printed models and then on patients were digitally scanned and objectively graded by prepCheck software for critical parameters, such as undercuts, taper, and occlusion reduction. Non-parametric tests were used to compare preparations on 3D-printed models and on patients performed by the study group and those on patients made by the control group. RESULTS: Initially, both groups reported similar perceptions of self-confidence and clinical skills levels. The study group significantly improved both aspects after the protocol. Analysis of the scanned preparations demonstrated that the study group removed less tooth structure from actual patients than from the initial 3D-printed models. In contrast, the control group showed excess occlusal clearance in their patients compared to the study group. CONCLUSIONS: Practicing patient-specific 3D-printed teeth before performing procedures clinically appears to enhance preparation quality and minimize unnecessary tooth reduction in early clinical experiences.

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OBJECTIVES: Our goal was to evaluate the clinical behavior of resin-based composite (RBC) restorations with sealed marginal defects using nano-filled flowable RBCs (FRS) compared with resin-based sealant (RBS); this work used marginal adaptation, marginal staining, and secondary caries according to the World Dental Federation (FDI) criteria. MATERIALS AND METHODS: This was a prospective, randomized, double-blind, controlled trial. Fifty-four patients who met the inclusion criteria (older than 18 years old; with high cariogenic risk determined by Cariogram software; and restorations with marginal defects, 3 and 4 according to FDI criteria) were randomly divided into three groups. There were three defective RBC restorations per patient and were repaired (n = 162). The groups were RBS-marginal sealing using a resin-based sealant (Clinpro Sealant, 3 M ESPE, MN, USA) plus adhesive (Single Bond Universal, 3 M ESPE, MN, USA); FRS-sealing using flowable resin (Filtek Flow Z350XT, 3 M ESPE, MN, USA) plus adhesive (Single Bond Universal, 3 M ESPE, MN, USA); and control-no repair treatment. All procedures were performed under complete isolation. Evaluations were evaluated at 1-week post treatment (baseline) as well as at 18 and 36 months after treatment regarding marginal adaptation, marginal staining, and secondary caries according to FDI criteria. The data were analyzed using the Wilcoxon test (α = 0.05) to compare the differences in each treatment group at different evaluation times. RESULTS: Marginal adaptation of micro-repaired RBC restorations were seen in patients with a high risk of caries using flowable resin composite or resin-based sealants. There were differences (P < 0.001) when baseline was compared at 18 and 36 months. Marginal staining showed differences when baseline was compared to 18 months (P < 0.001) and 36 months (P = 0.001) for both treatments. Secondary caries parameters for RBS treatment showed differences when baseline was compared to 36 months (P = 0.025) and when 18 months was compared to 36 months (P = 0.046). CONCLUSIONS: Micro-repair of RBC restorations resulted in clinical deterioration of marginal adaptation and marginal staining. Nano-filled flowable resin composites were sealed on defective restorations; 3 and 4 FDI marginal defects have better clinical performance to prevent secondary caries than resin-based sealants after 36 months. CLINICAL RELEVANCE: Micro-repair with RBS does not seem to be an effective treatment to prevent secondary caries.

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OBJECTIVE: This pilot study aimed to investigate the perceptions of dental students and their tutors of a deliberate simulated practice using patient-specific virtual and three-dimensional (3D) printed teeth models. This is before they perform their first indirect posterior tooth restoration on their patients. METHODS: Seventy-eight fourth-year dental students from the 2021 Comprehensive Clinic I course at the University of the Andes, Chile, were invited to participate in a deliberate practice protocol. This consisted of digitally scanning their patients' teeth, printing the files three-dimensionally, and loading them into a virtual reality (VR) dental simulator to create patient-specific models. Subsequently, they practiced the same indirect posterior restorations on these models before performing them on their actual patients. Perceptions about students' preparedness to perform tooth preparations before and after the protocol were collected from students and their tutors through surveys. RESULTS: Sixty-three students (43 female) and six clinical tutors (all male) participated in the study. Before practicing with their patient-specific models, most students believed they had the knowledge, practical skills, and self-confidence to perform indirect restorations on their patients. However, after the protocol, most students thought their self-confidence increased and felt better prepared to treat their patients. Most students preferred the 3D-printed models over the VR models to practice but mentioned that it did not feel like drilling dental enamel. Tutors believed that participating students had higher self-confidence when treating their patients and were more autonomous. CONCLUSIONS: This study demonstrated that students and clinical tutors had positive perceptions of practicing with patient-specific virtual and 3D-printed teeth models before students performed their first indirect restorations on their patients.

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STATEMENT OF PROBLEM: The light source stability of digital cameras and smartphones is important in shade matching in restorative and prosthetic dentistry to communicate objectively with the dental laboratory. Techniques that standardize the light source of such devices are lacking, and this limitation can lead to color mismatches, difficulties in color communication, and treatment documentation. PURPOSE: The purpose of this clinical study was to compare the magnitude of color difference (ΔE) among 3 shade selection methods during the fabrication of ceramic crowns: visual shade selection with a shade guide, digital shade selection with a digital camera and cross-polarizing filter, and digital shade selection with a smartphone and a light-correcting device. MATERIAL AND METHODS: Forty-five patients in need of ceramic crowns were enrolled, and shade selection was evaluated according to different protocols: visual shade selection (A-D shade guide and IPS Natural Die Material Shade Guide, sent to the dental laboratory technician via a laboratory prescription); digital shade selection with a digital camera (D7000; Nikon Corp) with an 85-mm lens and wireless close-up flash, with and without a cross-polarizing filter (Polar eyes); and digital shade selection with a smartphone and a light-correcting device (iPhone XS attached to Smile Lite MDP, with and without its cross-polarizing filter accessory). Information from the smartphone was imported to an app (IPS e.max Shade Navigation App; Ivoclar AG) that converted the reading to a shade and level of translucency for the ceramic restoration. For all photographs, a gray reference card with known color values was positioned by the mandibular teeth and was used for white balancing of the digital photographs with a software program. All photographs were edited and sent to the dental laboratory: white-balanced with the shade guide; white-balanced with the substrate shade guide; black and white; saturated; and cross-polarized. Ceramic crowns were made with the same lithium disilicate material (IPS e.max CAD; Ivoclar AG) and cemented with the same resin cement (RelyX Ultimate Clicker, A3 shade; 3M). The ΔE values between the crown and the adjacent tooth were determined. The data were analyzed by using a 1-way analysis of variance (ANOVA) and Tukey post hoc tests (α=.05). RESULTS: The mean ΔE between a cemented ceramic crown and the adjacent tooth in the visual shade selection group was 5.32, significantly different than both digital camera (ΔE=2.75; P=.002) and smartphone (ΔE=2.34; P=.001), which were not different from each other (P=.857). CONCLUSIONS: The digital shade selection with photographs acquired with both a digital camera and a smartphone with a light-correcting device showed a threshold within the acceptable values (ΔE<3.7), whereas the visual shade selection showed an average ΔE above the threshold for acceptable values (ΔE>3.7). The use of a gray reference card helped standardize the white balance from the digital images.

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OBJECTIVE: To evaluate color differences (ΔE) of different fabrication steps performed on a feldspathic ceramic and relative translucency parameter (RTP) after glazing; and to evaluate their effects on the color parameters: L*, a* and b*. MATERIAL AND METHODS: Computer-aided design/computer-aided manufacturing (CAD-CAM) feldspathic maxillary right central incisor ceramic crowns (Cerec Blocs; 1.4 mm thickness) were fabricated through scanning a model preparation and milling. A total of 20 specimens were used and different parameters were compared with each other for color difference (ΔE): original block, milling, polishing, glazing and try-in cements; RTP was measured after glazing. Color parameters (L*, a*, and b*) were evaluated after each step with a spectrophotometer (Vita Easyshade V) and compared using the CIEDE2000 formula. Statistical analyses were done using one-way ANOVA and post-hoc tests. RESULTS: The highest ΔE value was observed for Original versus Milling group (4.73) and the lowest for Polishing versus Glazing (0.49). RTP after glazing presented a value of 12.01. L*, a*, and b* parameters were different among groups. Milling group was the one that presented more differences compared to the Original block regarding L*, a*, and b* parameters. CONCLUSIONS: Different fabrication steps resulted in perceptible color differences within themselves, and L*, a*, and b* parameters changed according to each step. All milling specimens presented unacceptable color differences when compared to the other steps, and milling specimens showed all color parameters (L*, a*, and b*) statistically different compared to the Original block. A high RTP value was observed, demonstrating that, at 1.4 mm thickness, the feldspathic ceramic presented high translucency, showing that opacification of substrate might be necessary. CLINICAL SIGNIFICANCE: Different fabrication steps can greatly affect the optical properties of the feldspathic ceramic restoration studied and cause a relevant impact when compared to the ceramic block itself. Crowns evaluated right after milling presented the highest color differences. In order to obtain optical properties as close as possible to the original feldspathic ceramic block, either polishing or polishing and glazing needs to be performed.

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Introducción: Gracias a su eficiencia y al uso exclusivo de cerámicas libres de metal, en rehabilitación oral se ha logrado alcanzar los estándares estéticos y mecánicos, manteniendo o, incluso, superando, la calidad de los tratamientos en comparación con las restauraciones metal cerámicas tradicionales. Actualmente los mecanismos de confeccion de cerámica libre están evolucionando cada vez mas hacia las tecnologías maquinadas CAD-CAM y disminuyendo su producción mediante la técnica de Inyeccion PRESS. Objetivo: Comparar la tasa de supervivencia de prótesis fija unitaria realizadas con cerámicas feldespáticas convencionales y reforzadas con disilicato de litio, confeccionadas con sistema CAD/CAM de CEREC® chair-side, en comparación con el método de inyección de laboratorio PRESS convencional de prensión. Métodos: Revisión sistemática realizada a través de búsqueda de evidencia científica en PubMed, PubMed Clinical Queries, Epistemónikos, Tripdatabase, Cochrane Library, recursos electrónicos de la Universidad de los Andes y bibliografía retrógrada, de artículos publicados hasta el año 2019. Se incluyeron todos aquellos estudios referentes a prótesis fija unitaria de cerámicas feldespática convencional y feldespática reforzada con disilicato de litio, confeccionadas mediante CAD/CAM y/o método convencional. Resultados: Un total de 28 artículos cumplieron los criterios de inclusión: 21 estudios observacionales de cohorte, 4 ensayos clínicos aleatorizados y 3 no aleatorizados. A corto y mediano plazo, CAD/CAM de CEREC® registró tasas de supervivencia de 98 por ciento y 91,9 por ciento, respectivamente. El sistema convencional registró tasas de supervivencia de 97,5 por ciento a corto plazo y 93 por ciento a mediano. Conclusiones: A corto plazo se describe en la literatura que CAD/CAM de CEREC® tuvo una tasa de supervivencia ligeramente superior al sistema convencional. Por otro lado, a mediano plazo CAD/CAM de CEREC® presentó una leve disminución respecto al sistema convencional. Aún no hay estudios disponibles para determinar la supervivencia clínica de los tratamientos a largo plazo(AU)

Introduction: Thanks to its efficiency and the exclusive use of metal-free ceramics, in oral rehabilitation it has been possible to achieve aesthetic and mechanical standards, maintaining or even exceeding the quality of the treatments compared to traditional metal-ceramic restorations. Currently, free ceramic manufacturing mechanisms are increasingly evolving towards CAD-CAM machined technologies and decreasing their conventional production through the PRESS Injection technique. Objective: Compare the survival rate of single-unit fixed prostheses made with conventional feldspathic ceramics and reinforced with lithium disilicate by the CEREC® CAD/CAM chairside system, with the conventional PRESS laboratory injection method. Methods: A systematic review was conducted of scientific evidence included in papers published until the year 2019 in PubMed, PubMed Clinical Queries, Epistemonikos, Tripdatabase, Cochrane Library, electronic resources of Los Andes Peruvian University, and retrograde bibliography. The papers selected dealt with conventional and lithium-disilicate reinforced feldspathic ceramic single-unit prostheses made by CAD/CAM and/or the conventional method. Results: A total 28 papers met the inclusion criteria. Of these, 21 were observational cohort studies, four were randomized clinical assays and three were non-randomized assays. Short- and mid-term, CEREC® CAD/CAM achieved survival rates of 98 percent and 91.9 percent, respectively. The conventional system achieved survival rates of 97.5 percent short-term and 93 percent mid-term. Conclusions: As described in the literature, CEREC® CAD/CAM had a slightly higher survival rate than the conventional system in the short term. In the medium term, however, CEREC® CAD/CAM displayed a slight reduction in comparison with the conventional system. No studies are available to determine the clinical survival of the treatments in the long term(AU)

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INTRODUCTION: Digital workflow is currently available for different fields of dentistry. Additionally, to clinical use, digital technology is focused on the education and training of students. The objective of this study was to show the potential benefit of the use of digital CAD / CAM technology and assisted training software in the evaluation and improvement of student skills in preclinical and clinical environments. MATERIALS AND METHODS: 30 models of dental preparations were digitalised and analysed by PrepCheck software, after that was used the PrepCheck Report tool, gathering the results of the analysis in an automatically created report and containing the following parameters: analysis of the conicity, distance between a preparation and the opposing jaw, analysis of the type of preparation, quality of the margin and total occlusal convergence. RESULTS: The use of the PrepCheck Pro 2.1 software makes evident the errors made by the students during the biomechanical preparation, since they generally change the inclination, in order to have less difficulties to comply with the parameters established in the preparations. Regarding the evaluated parameters for anterior and posterior fixed prosthesis) such as: 'Conicity', 'Type of preparation' and 'Distance to the antagonist', the preparations, in their majority, were classified within the tolerance range with of 50-60%, 80-93% and 53-67%, respectively. CONCLUSION: This pilot study demonstrated the benefits of using software and CAD/CAM technology in both preclinical and clinical environments for teaching and learning. Its use on preclinical environments allows the student observe qualitatively and quantitatively a preparation flaws when compared to a master's preparation. Lastly, the ease of visualising errors associated with magnification would allow students to improve their skills.

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STATEMENT OF PROBLEM: During the selection of tooth color, subjective communication with the laboratory and an incorrect color registration technique can lead to a poor color match of a restoration to adjacent teeth and oral structures. PURPOSE: The purpose of this cross-sectional study was to compare color registration and color matching in a young Chilean population with 3 different methods: visual with a shade guide, digital visual with a cross-polarized filter, and instrumental with a spectrophotometer. MATERIAL AND METHODS: A total of 60 young volunteers were selected for tooth color registration of the maxillary right central incisor by using 3 different methods. Tooth color registration was performed using the CIELab and ΔE coordinate system. RESULTS: Significant differences were detected between the coordinates recorded by the visual analog method in comparison with the other 2 methods. In contrast, no significant differences were found between the L∗ and b∗ coordinates of the spectrophotometer and the digital visual method with use of a cross-polarization filter. The ΔE obtained between the visual shade and spectrophotometer was 7.35, and the ΔE between the digital visual method with the use of a cross-polarization filter and the spectrophotometer was 6.12. CONCLUSIONS: No statistically significant differences were observed in the digital image with the cross-polarization filter and the spectrophotometer in the L∗ and b∗ coordinate of the CIELab system. In contrast, the visual analog method led to large differences with the other methods under study. The ΔE of the digital visual method with the use of cross-polarization filters and the spectrophotometer was 6.2, considered as an acceptable color mismatch (<ΔE 6.8).

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RESUMEN Introducción: Durante la realización de prótesis fijas, el paciente puede presentar sensibilidad posoperatoria. Se ha descrito en la literatura diferentes prevalencias de esta sensibilidad, las cuales varían ampliamente, entre 3 por ciento y 34 por ciento. Objetivo: Determinar la prevalencia e intensidad de sensibilidad posoperatoria en el tratamiento de prótesis fija sobre diente vital. Métodos: se realizó un estudio clínico piloto descriptivo. La muestra fue de 35 dientes tratados de 20 pacientes. Esta fue conformada por pacientes atendidos por alumnos del Centro Odontológico de la Universidad de Los Andes, a los cuales se les realizó un tratamiento en base a prótesis fija sobre diente vital, desde el mes de abril hasta octubre del año 2015. Se registró la sensibilidad durante el tratamiento por medio la escala visual análoga a través de un diario completado por el paciente y por la escala verbal numérica aplicada por el investigador en distintas etapas clínicas. Resultados: Se observó una prevalencia del 31,4 por ciento con una intensidad de 0,62 ± 0,49 según la escala visual análoga y de 0 según la escala verbal numérica. Conclusiones: la prevalencia de la sensibilidad posoperatoria se aproximó al rango más alto descrito en la literatura. La intensidad de la sensibilidad observada fue leve a imperceptible clínicamente(AU)

ABSTRACT Introduction: During fixed prosthodontic treatment, patients may present postoperative hypersensitivity. The prevalence rates contained in the literature on the topic range from a mere 3 percent to 34 percent. Objective: Determine the prevalence and intensity of postoperative hypersensitivity during fixed prosthodontic treatment of vital teeth. Methods: A pilot descriptive clinical study was conducted. The sample was 35 treated teeth from 20 patients. These patients had been treated by students from the Dental Center at the University of Los Andes, and had undergone fixed prosthodontic treatment on vital teeth from April to October 2015. Hypersensitivity during the treatment was recorded with the visual analog scale based on a diary kept by patients and on the verbal numerical rating scale as applied by the researcher at the various clinical stages. Results: Prevalence was 31.4 percent with an intensity of 0.62 ± 0.49 by the visual analog scale and of 0 by the verbal numerical rating scale. Conclusions: The prevalence of postoperative hypersensitivity approached the highest range described in the literature, whereas the intensity of hypersensitivity ranged from mild to clinically imperceptible(AU)

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Las piezas dentarias vitales que reciben tratamiento en base a prótesis dental fija (PDF) sufren un proceso inflamatorio pulpar durante su preparación, esta respuesta inflamatoria puede ser transitoria o perpetuarse y convertirse en un daño pulpar. Como consecuencia se puede presentar sensibilidad post operatoria en algunos pacientes durante el tratamiento y esta podría estar relacionada con ciertos factores de riesgo. El objetivo del presente trabajo es describir los factores de riesgo relacionados con la sensibilidad postoperatoria termica, quimica o mecanica en el tratamiento mediante prótesis dental fija. Método: Se utilizaron diferentes bases de datos para buscar estudios que incluyeran las siguientes palabras clave: sensibilidad dental, hipersensibilidad dental, respuesta pulpar, corona, prótesis fija, postoperatorio, post cementación, preparación dentaria. Todos los estudios encontrados se analizaron según el nivel de evidencia, la calidad del informe y las implicaciones éticas. Resultados: Se seleccionaron un total de 43 artículos. De ellos, 10 correspondieron a estudios clínicos, 7 revisiones de literatura y 26 estudios in vitro. El nivel de evidencia, la calidad del informe y las consideraciones éticas fueron calificados como regulares. Conclusiones: La evidencia existente describe algunos factores de riesgo relacionados con la sensibilidad postoperatoria en tres etapas del proceso de confección de una prótesis dental fija, pero sin embargo no es concluyente respecto a su mecanismo de origen ni prevención por lo que se sugiere realizar estudios clínicos aleatorizados.

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OBJECTIVE: This study evaluated different tooth shapes from female and male genders, matching them with the firstly proposed pure basic forms, and proposed different hybrid shapes; it also evaluated the percentage of correct gender identification of lay people, dentists and dental students. MATERIALS AND METHODS: Standardized digital photos were taken from 460 people and analyzed by 3 experts regarding genders and tooth forms: pure basic forms-oval (O), triangular (T), square (S) and rectangular (R); and combined hybrid forms-oval-rectangular (OR), triangular-rectangular (TR), triangular-oval (TO), square-oval with flat lateral incisors (SOF), and square-oval with scalloped lateral incisors (SOS). Then, correct gender identification (%) was evaluated among lay people, dentists and dental students (n = 10). RESULTS: Pure forms showed less prevalence in the population studied (O:6.52%; S:3.48%; T:3.26%; R:2.39%) than hybrid ones (TO:20.87%; SOS:20.65%; OR:19.57%; SOF:16.96%;TR: 6.30%). Tooth gender selection among different evaluators was not significantly different (≈50% correct answers). CONCLUSIONS: No correspondence exists between tooth shapes and patient genders. Pre-standardized pure tooth forms appeared less than hybrid ones, while the most frequently found in the population studied were TO, SOS, and OR forms, disregarding genders. CLINICAL SIGNIFICANCE: Esthetic perception is an increasingly important criterion critical to satisfy patients. The correlation of reported tooth shapes with specific genders was not reliably observed in natural smiles. Tooth shapes should be selected according to the wishes of the patient rather than by previously believed gender specific tooth shapes. Pure basic tooth forms should be complemented with the addition of combination forms to more accurately portray forms found in nature.

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Aim Describe the location of traumatic lesions of the oral mucosa that develop after the installation of complete dentures, as well as to quantify the number of post-operative controls that are required. A descriptive study was conducted by examining 84 patients who attended the dental center of Universidad de Los Andes, San Bernardo, during the period from July 2012 to July 2013. A sample of 120 edentulous patients was obtained. After the fabrication and installation of the complete dentures, at least 3 post-operative controls were performed and the location of oral lesions was recorded. Documentation of the association between the patient's clinical variables and the appearance of oral lesions during the first 3 controls was performed using a logistic regression. Results For maxillary dentures, 5 post-operative visits were made and 6 controls for mandible dentures. In the upper jaw the anatomical areas of higher incidence of traumatic injuries were: canine fossa (23.9%), average bridle (23.1%), and distobuccal sulcus (20.1%). In the lower jaw, the highest number of lesions were recorded on the anterior lingual flank (16.5%), anterior and posterior lingual flank (13.4%), and distobuccal sulcus (12.8%). A significant association was observed between subjects who reported consumption of cholesterol-lowering medications and the development of traumatic lesions of the oral mucosa (OR: 0.25 and 95% CI: 0.055-0.939). The installation of complete dentures does not determine that the treatment has ended. Post-operative controls are needed to assess areas of erythema and ulceration.

Objetivo Describir la ubicación y frecuencia de las lesiones traumáticas de la mucosa oral que se generan después de la instalación de las prótesis dentales completas, y cuantificar el número de controles postoperatorios necesarios. Se realizó un estudio descriptivo, examinando a 84 pacientes que asistieron al centro dental de la Universidad de Los Andes, durante el período comprendido entre de julio de 2012 y julio del de 2013. Se obtuvo una muestra de 120 pacientes edéntulos. Después de la fabricación e instalación de las dentaduras completas se realizaron por lo menos 3 controles postoperatorios y la localización de las lesiones orales fue registrada. La documentación de la asociación entre las variables clínicas de los pacientes y la aparición de lesiones orales durante los 3 primeros controles fue realizado por medio de una regresión logística. Resultados Para prótesis maxilar 5 visitas de controles postoperatorios fueron realizados y 6 para mandibulares. En el maxilar superior las zonas de mayor incidencia de lesiones traumáticas fueron: fosa canina (23,9%), flanco medio (23,1%) y distovestibular del surco (20,1%). En la mandíbula se registraron mayor frecuencia de las lesiones en el flanco lingual anterior (16,5%), anterior y posterior (13,4%) y distovestibular del surco (12,8%). Una asociación significativa se observó entre los sujetos que reportaron consumo de medicamentos reductores del colesterol y el desarrollo de las lesiones traumáticas de la mucosa oral (o: 0,25 e IC: 0,055-0,939). La instalación de las prótesis dentales completas no determina que el tratamiento haya terminado. Los controles postoperatorios son necesarios para evaluar las áreas de eritema y ulceración.

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