Effectiveness of commercially available denture adhesives on retention of mandibular complete denture in resorbed mandibular ridge: an in vitro study / Efectividad de los adhesivos disponibles comercialmente sobre la retención de prótesis removibles completas mandibulares en el reborde mandibular reabsorbido: un estudio in vitro

Background: Denture adhesives are alternatives used to improve retention, stability, comfort and satisfaction in patients with complete dentures. Evidence on the effectiveness of denture adhesives on resorbed mandibular ridges is scarce. Among the many commercially available denture adhesives, the ideal material for the severely resorbed mandibular ridge remains in dispute. Objective: The aim of this study was to evaluate the effectiveness of different quantities of four commercially available denture adhesives on the retention of mandibular complete dentures in severely resorbed ridges. Materials and Methods: A resorbed edentulous mandibular ridge model was manufactured in acrylic resin. A denture base was made and three loops were attached to it. Four commercially available denture adhesives (Fixodent, Perlie White, Fiftydent and Polident) were tested in amounts of 0.2 g, 0.4 g, 0.6 g, 0.8 g and 1.0 g. The acrylic resin model was evenly moistened with 1 ml of water and a weighted amount of adhesive material was applied to the denture base. The universal testing machine engaged the loops fixed on the denture base and applied the vertical displacement force. The maximum vertical displacement force values were recorded for each denture adhesive material at different amounts. Statistical calculation was performed using Kruskal Wallis with Bonferroni post hoc correction. Results: Statistically significant differences were observed in the mean values of the vertical displacement force for adhesive amounts of 0.2 g, 0.4 g, 0.6 g and 1.0 g (p<0.05) between the four adhesive materials tested. Statistically significant differences were observed when four denture adhesives were compared to each other in different amounts (p<0.05). Statistically significant differences were observed between different amounts for each of four denture adhesives (p<0.05). Conclusions: Among the four materials tested, Polident showed greater effectiveness at 0.6 g and 0.8 g, Fittydent at 0.6 g, 0.8 g and 1 g, Fixodent at 0.4 g and 0.6 g and Perlie White at 1 g and 0.8g quantity to resist vertical displacement. forces on the severely resorbed mandibular crest. Using an appropriate amount of denture adhesive allows for proper retention of the denture; Replacement of this adhesive is necessary once a day.

Introducción: Los adhesivos para prótesis dentales son alternativas utilizadas para mejorar la retención, la estabilidad, la comodidad y la satisfacción en los pacientes con prótesis completas. La evidencia sobre la efectividad de los adhesivos para prótesis dentales en los rebordes mandibulares reabsorbidos es escasa. Entre los muchos adhesivos para prótesis dentales disponibles comercialmente, sigue estando en disputa cuál es el material ideal para el reborde mandibular severamente reabsorbido. Objetivo: El objetivo de este estudio fue evaluar la efectividad de diferentes cantidades de cuatro adhesivos para prótesis dentales disponibles comercialmente sobre la retención de prótesis dentales completas mandibulares en reborde mandibular reabsorbido severamente. Materiales y Métodos: Se fabricó un modelo de reborde mandibular edéntulo reabsorbido en resina acrílica. Se hizo una base para la prótesis y se le colocaron tres bucles. Se probaron cuatro adhesivos para dentaduras postizas disponibles comercialmente (Fixodent, Perlie White, Fiftydent y Polident) en cantidades de 0,2 g, 0,4 g, 0,6 g, 0,8 g y 1,0 g. El modelo de resina acrílica se humedeció uniformemente con 1 ml de agua y se aplicó la cantidad correspondiente de material adhesivo sobre la base de la dentadura. La máquina de prueba universal enganchó los bucles fijados en la base de la dentadura postiza y aplicó la fuerza de desplazamiento vertical. Se registraron los valores máximos de fuerza de desplazamiento vertical para cada material adhesivo para dentaduras postizas en diferentes cantidades. El cálculo estadístico se realizó utilizando Kruskal Wallis con corrección post hoc de Bonferroni. Resultado: Se observaron diferencias estadísticamente significativas en los valores medios de la fuerza de desplazamiento vertical para cantidades de 0,2 g, 0,4 g, 0,6 g y 1,0 g (p<0,05) entre los cuatro materiales adhesivos para prótesis dentales probados. Se observaron diferencias estadísticamente significativas cuando se compararon cuatro adhesivos para prótesis dentales entre sí en diferentes cantidades (p<0,05). Se observaron diferencias estadísticamente significativas entre diferentes cantidades en los cuatro adhesivos para prótesis (p<0,05). Conclusión: De los cuatro materiales probados, Polident mostró mayor efectividad a 0,6 g y 0,8 g, Fittydent a 0,6 g, 0,8 g y 1 g, Fixodent a 0,4 g y 0,6 g y Perlie White a 1 g y 0,8 g para resistir fuerzas de desplazamiento vertical en la cresta mandibular severamente reabsorbida. El uso de una cantidad adecuada de adhesivo para dentaduras postizas permite una retención adecuada de la dentadura postiza; El reemplazo de este adhesivo es necesario una vez al día.

Fotogrametría de modelos dentales de yeso / Photogrammetry of dental plaster models

El presente estudio busca definir los parámetros de la cámara fotográfica y encuadre de la imagen para generar fotografías estandarizadas a modelos dentales de yeso que permitan realizar mediciones intermaxilares a través de fotogrametría, y que estas distancias sean tan confiables y válidas como el registro físico. Se realizó medición directa de los modelos con compás de Korkhaus y medición indirecta a través de fotogrametría digital, evaluando si existía diferencia estadística entre ambas mediciones. Como resultado, no se observaron diferencias significativas entre el protocolo digital con un objetivo 100 mm y magnificación 1:4 en comparación con las mediciones directas, por lo que se concluye que con los parámetros seleccionados se logra una adecuada precisión en la fotogrametría respecto a la medición directa.

This study aims to compare the different parameters of the photographic camera with the digital image framing to standardize dental model photography, in order to take intermaxillary measurements through photogrammetry, and so that these distances are as reliable and valid as the physical record. Direct measurement of the models was made with a Korkhaus compass, and indirect measurement through digital photogrammetry, evaluating whether there was a statistical difference between both measurements. As a result, no significant differences were observed between the digital protocol with a 100 mm objective and 1:4 magnification and the direct measurements. It is concluded that with the selected parameters, adequate precision is achieved in photogrammetry, when compared to the direct measurement.

Precisão dos escaneamentos intraorais e modelos 3D, com diferentes escâneres e softwares: revisão sistemática / Accuracy of intraoral scanning and 3D models, with different scanners and software: systematic review

Objetivo: Esta revisão sistemática investigou se a precisão dos escaneamentos intraorais e modelos 3D com diferentes escâneres e softwares, é suficiente para os clínicos aceitarem e implementarem as novas tecnologias como critério de diagnóstico e planejamentos dos tratamentos. Material e métodos: Protocolo PROSPERO número CRD42020218151. Duas revisoras realizaram uma pesquisa avançada de banco de dados eletrônico, sem restrição de idioma ou data, no MEDLINE/PubMed; Embase; BVS/LILACS; Scopus; Cochrane Library; Google Scholar e Web of Science até janeiro de 2021. Os estudos foram escolhidos por título e resumo para triagem, de acordo com os seguintes critérios de inclusão: Estudos Clínicos in vivo e in vitro (pacientes, modelos de gesso de pacientes e manequins simulando bocas humanas) com os diferentes softwares e técnicas de escaneamento intraoral comparando a acurácia, fidelidade e/ou precisão como desfecho dos escaneamentos intraorais, dos modelos virtuais em 3D com modelos de gesso; com um mínimo de 5 pacientes escaneados sem limite de idade ou gênero; texto completo acessível; nos estudos de coorte, transversais e caso-controle. Após a leitura do texto completo os artigos foram excluídos de acordo com os seguintes critérios: 1) estudos com menos de 5 pacientes; 2) estudos em animais; 3) revisão sistemática, descrição de técnica, intervenções, protocolos; 4) escaneamentos por Ressonância Magnética ou Tomografia computadorizada; 5) estudos em que não foram utilizados scanners intraorais. Resultados. Dos 4410 estudos inicialmente identificados, 16 preencheram os critérios de inclusão. O guia PRISMA foi utilizado para redação da revisão e a ferramenta ROBINS-1 da Cochrane foi utilizada para análise de viés. Os estudos incluídos na sua maioria mostraram diferenças estatisticamente significativas entre os resultados das moldagens convencionais e digitais, porém também demonstraram que as diferenças não têm significância clínica. Conclusões: Esta revisão sistemática permitiu levantar dados que demonstraram que os escaneamentos intraorais não são superiores às moldagens convencionais, mas de acurácia equivalente com confiabilidade para o uso das imagens digitais conseguidas por escaneamento intraoral e dos modelos digitais provenientes destes escaneamentos.

Resolución de maloclusión con severo escalón anterior empleando fuerzas diferenciales / Resolution of a malocclusion with a severe anterior step employing differential forces

Paciente de 21 años de sexo masculino con una distoclusión esqueletal y alveolo dentaria severa, hábito de succión del dedo que contribuye a agravar el escalón de 15 mm. Demanda tratamiento para mejorar su oclusión y estética. Si bien lo indicado es un tratamiento ortodóncico con cirugía ortogná- tica para modificar su perfil muy convexo con una distancia mentocervical acortada, no es aceptado por el paciente, planificándose entonces camuflaje ortodóncico con exodoncias de PD 14 y 24 y reduc- ción del escalón mediante anclaje diferencial que emplea fuerzas de volcamiento para no perderlo dado el gran overjet a reducir. Habiendo varias piezas dentarias con anomalías de color, defectos en el esmalte, una corona metálica en PD 36 y limitacio- nes presupuestarias se realizó la estética final con reconstrucciones de resina (AU)

A 21-year-old male patient with a severe skeletal and alveolar distoclusion, finger sucking habit that contributes to aggravate the 15 mm step. He demands treatment to improve its occlusion and aesthetics. Although orthodontic treatment with orthognathic surgery is indicated to modify its highly convex profile with a shortened mentocervical distance, it is not accepted by the patient, so orthodontic camouflage is planned with extractions of 14 and 24 and reduction of the step by means of differential anchorage that uses overturning forces so as not to lose anchorage due to the great overjet. Having several dental pieces with color anomalies, enamel defects, a metallic crown in 36 and budgetary limitations, the final aesthetics was performed with resin reconstructions (AU)

Preliminary evaluation of the trueness of 5 chairside 3D facial scanning techniques / 北京大学学报(医学版)

OBJECTIVE@#To quantitatively evaluate the trueness of five chairside three-dimensional facial scanning techniques, and to provide reference for the application of oral clinical diagnosis and treatment.@*METHODS@#The three-dimensional facial data of the subjects were collected by the traditional professional three-dimensional facial scanner Face Scan, which was used as the reference data of this study. Four kinds of portable three-dimensional facial scanners (including Space Spider, LEO, EVA and DS-FScan) and iPhone Ⅹ mobile phone (Bellus3D facial scanning APP) were used to collect three-dimensional facial data from the subjects. In Geomagic Studio 2013 software, through data registration, deviation analysis and other functions, the overall three-dimensional deviation and facial partition three-dimensional deviation of the above five chairside three-dimensional facial scanning technologies were calculated, and their trueness performance evaluated. Scanning time was recorded during the scanning process, and the subject's comfort was scored by visual analogue scale(VAS). The scanning efficiency and patient acceptance of the five three-dimensional facial scanning techniques were evaluated.@*RESULTS@#DS-FScan had the smallest mean overall and mean partition three-dimensional deviation between the test data and the reference data, which were 0.334 mm and 0.329 mm, respectively. The iPhone Ⅹ mobile phone had the largest mean overall and mean partition three-dimensional deviation between the test data and the reference data, which were 0.483 mm and 0.497 mm, respectively. The detailed features of the three-dimensional facial data obtained by Space Spider were the best. The iPhone Ⅹ mobile phone had the highest scanning efficiency and the highest acceptance by the subject. The average scanning time of the iPhone Ⅹ mobile phone was 14 s, and the VAS score of the subjects' scanning comfort was 9 points.@*CONCLUSION@#Among the five chairside three-dimensional face scanning technologies, the trueness of the scan data of the four portable devices had no significant difference, and they were all better than the iPhone Ⅹ mobile phone scan. The subject with the iPhone Ⅹ scanning technology had the best expe-rience.

Efectividad de tres métodos de desobturación sobre modelos réplica / Effectiveness of three unsealing methods on replica models

El objetivo fue evaluar la eficacia de remoción del material de obturación y el tiempo empleado para la desobturación con tres métodos diferentes, en modelos réplica. Se utilizaron 24 modelos réplica de premolares inferiores instrumentados con sistema Protaper Gold hasta F4, irrigación NaOCl 2,5% y ED-TAC 17%. Obturación termoplastizada sistema Fast Pack Pro. La muestra (n=24) se dividió aleatoriamen-te en tres grupos experimentales (n=8) sometidos a distintos métodos de desobturación. Grupo 1: fresas Gates Glidden II/III y limas Hedstroem. Grupo 2: lima Medium sistema Wave One Gold y punta ultrasóni-ca Ultra X, (Eighteeth). Grupo 3: lima Rotate 35/04 y punta ultrasónica R1 Clearsonic, (Helse). Se midió el tiempo de desobturación. Las piezas se radiogra-fiaron con radiovisiógrafo digital RVG 5200 (Cares-tream), y fueron procesadas con software Image-J. Al analizar cantidad de material de obturación rema-nente, la prueba de Kruskal-Wallis (p<0,05), mostró diferencias estadísticamente significativas entre grupos 2 y 3. Grupo 1 no mostró diferencias signifi-cativas con los otros dos (p>0,05). Al analizar tiempo de desobturación, el test de Kruskal-Wallis no deter-minó diferencias significativas entre grupos 1 y 2 (p>0,05), el grupo 3 tuvo diferencias estadísticamen-te significativas con los grupos 1 y 2 (p<0,05). En con-clusión, ninguno de los sistemas de desobturación evaluados logró eliminar la totalidad del material de obturación. El que combinó limas rotatorias con punta ultrasónica de retratamiento fue el que mos-tró mayor efectividad de remoción y demandó menor tiempo de trabajo (AU)

Objective: to evaluate the effectiveness of obturation material removal and the time that the procedure took, when performing the retreatment with three different methods, in replica models of mandibular premolars. Materials and methods: 24 replica models of lower premolars instrumented with Protaper Gold system up to F4, 2.5% NaOCl irrigation and 17% ED-TAC were used. Thermoplastized sealing with Fast Pack Pro system. The sample (n=24) was randomly divided in three experimental groups (n=8) subjected to different unsealing methods. Group 1: Gates Glid-den burs II and III and Hedstroem files. Group 2: Wave One Gold Medium file system and Ultra X ultra-sonic tip, (Eighteeth). Group 3: Rotate 35/04 file and R1 Clearsonic ultrasonic tip (Helse). Unsealing time was measured. The samples were radiographed with a digital radiovisiograph RVG 5200 (Carestream), and processed with Image-J software. When analyzing the amount of remaining filling material, Kruskal-Wallis test showed statistically significant differences be-tween groups 2 and 3 (p<0,05). Group 1 did not show significant differences with the other two (p>0,05). When analyzing unsealing time, Kruskal-Wallis test determined that there were no significant differ-ences between groups 1 and 2 (p>0,05), but group 3 had statistically significant differences with the other two (p<0.05). None of the unsealing systems evalu-ated managed to eliminate all of the sealing material. The group that combined rotary files with ultrasonic retreatment tip showed the greatest removal effec-tiveness and required less work time (AU)

Métodos para medir asimetrías sagitales y transversales en los modelos de estudio de ortodoncia / Methods to measure sagittal and transverse asymmetries in orthodontic study models

Introducción Para el diagnóstico acertado en el tratamiento de los pacientes de ortodoncia se requiere de una serie de exámenes auxiliares, que son herramientas esenciales en ortodoncia; sin embargo, encontramos cierto grado de dificultad para la valoración de asimetrías dentarias en los hemiarcos de cada arcada dentaria; la importancia de la correcta valoración de las asimetrías es ya ampliamente mencionada en diferentes estudios, porque nos ayudará con la localización co-rrecta, de los dientes en su arcada,al final del tratamiento En la actualidad existe poca literatura sobre los métodos para evaluar y diagnosticar las alteraciones por hemiarcos, especialmente en el plano transversal. Objetivo acer una revisión de literatura sobre los métodos de medición de las asimetrías dentarias intra-arco para poder identificar y cuantificar las alteraciones dentarias en los tres planos del espacio en su respectiva arcada dentaria, el Método para los términos de búsqueda de la información fueron: dental and facial asymmetry, molar asymmetry in ortho-dontics, arch width prediction indices, as well as transverse discrepancies, para tal efecto se empleó Pubmed, Medline, Scielo, Schoolar Google, de los cuales se recopilaron 80 artículos relacionados con nuestro tema de estudio y solo se eligieron 30 artículos y 6 libros de ortodoncia en los que se sustenta este artículo. Resultados En el presente artículo presentamos las herramientas con las que contamos para el diagnóstico de la asimetría dentaria intra-arcos como la placa de Sthmuch y la placa milimetrada de Korkhaus, y finalmente proponemos un método que nos permite cuantificar objetivamente la asimetría en los tres plano del espacio de una manera sencilla, reproducible y de fácil almacenaje en un computador. Conclusión La etapa del diagnóstico es importante porque permitirá obtener la mayor y mejor información de las alteraciones dentarias que presenta el paciente, siendo las alteraciones transversales las más difíciles de cuantificar por que la mayoría de los estudios e índices, ya que solo evidencian las distancias de dientes contra laterales, los cuales son datos limitados pero que aún así contribuyen en el diagnóstico, el método de la placa de Sthmuch, Korkhaus y Bernklau son propuesta para medir las asimetrías dentarias intraarcos, no en tanto es desgastador para el operador y sus resultados objetivos radica en la experiencia del operador; el método KLO nos permite cuantificar objetivamente la falta de sime-tría dentaria en cada arcada de una manera fácil, reproducible y de almacenaje en un computador o en un archivo.

Introduction The correct diagnosis in the treatment of orthodontic patients requires a series of auxiliary examinations, which are essential tools in orthodontics, however we found a certain de-gree of difficulty in assessing dental asymmetries in the hemiarchs of each dental arch; The im-portance of the correct assessment of asymmetries is already widely mentioned in different stud-ies, because it will help us with the correct location of the teeth in their arch, at the end of the treatment. Currently there is little literature on the methods to evaluate and diagnose hemiarchal alterations, especially in the transverse plane. Objective Is to review the literature on the methods of measuring intra-arch dental asymmetries in order to identify and quantify dental al-terations in the three planes of space in their respective dental arch. Method The search terms of the information were: dental and facial asymmetry, molar asymmetry in orthodontics, arch width prediction indices, as well as cross-sectional discrepancies. Pubmed, Medline, Scielo, Schoolar Google, of which 80 articles related to our study topic were collected and only 30 articles and 6 orthodontic books were chosen on which this article is based, Results Also in this article we present the tolos that we have for the diagnosis of intraarch dental asymmetry such as the Sth-much plate and the Korkhaus millimeter plate, and finally we propose a method that allows us to objectively quantify the asymmetry in the three space plan in a simple, reproducible way and easy to store on a computer. Conclusión The stage of diagnosis is important because it will allow obtain-ing the greatest and best information on the dental alterations that the patient presents, being the transversal alterations the most difficult to quantify because most studies and indices, since they only show the distances of Contralateral teeth, which are limited data but still contribute to the diagnosis, the Sthmuch, Korkhaus and Bernklau plate method are proposed to measure intra-arch dental asymmetries, not as it is wearisome for the operator and his patients. objective results lies in the experience of the operator; The KLO method allows us to objectively quantify the lack of dental symmetry in each arch in an easy, reproducible way that can be stored on a computer or in a file.

Estudo do nível de conhecimento e interesse do cirurgião dentista no diagnóstico e tratamento da síndrome da apnéia/hipopnéia obstrutiva do sono (SAHOS) / Study of the level of knowledge and interest of the dental surgeon in the diagnosis and treatment of obstructive sleep apnea/hypopnea syndrome (OSAHS)

Atualmente, o tratamento do ronco primário e da Síndrome da Apnéia/Hipopnéia Obstrutiva do Sono (SAHOS)1 através de aparelhos intra-orais (AIO) tem recebido a atenção dos pesquisadores pela comprovada eficácia destes dispositivos. Os aparelhos mais indicados são os reposicionadores de mandíbula que promovem um avanço mandibular, afastando os tecidos da orofaringe superior, o que evita a obstrução parcial ou total da área. Sua indicação é para casos de ronco primário e apnéias leves e moderadas2, no entanto é necessário que os candidatos apresentem número de dentes suficientes com saúde periodontal para a ancoragem do aparelho. Por ser uma doença de consequências sistêmicas graves, o tratamento da SAHOS é em sua essência de responsabilidade do médico especialista na área, porém o cirurgião dentista deve ter conhecimento para diagnosticar e tratar, quando o AIO for a opção terapêutica. A interpretação da polissonografia, exame que diagnostica e conduz para a escolha correta do tratamento, e dos dados cefalométricos são os principais quesitos ao Cirurgião Dentista que se propõe a tratar portadores da SAHOS. Nesse trabalho foi elaborado um questionário e aplicado aos cirurgiões dentistas de três diferentes cidades do Estado de São Paulo para que fosse possível avaliar o conhecimento desses profissionais a respeito do diagnóstico e tratamento da SAHOS. 70 Cirurgiões Dentistas foram entrevistados e os resultados mostraram que 70% destes têm interesse em trabalhar com os AIOs. Esse grupo se relacionou estatisticamente significante com aqueles que afirmaram já terem sido alguma vez questionado por algum paciente a respeito desse tratamento. Quanto à criação de uma especialidade para essa área, os profissionais da área de prótese e implante se mostraram mais interessados. E, do número total de entrevistados, apenas 25% já tiveram contato com esse tipo de aparelho, mas não conhece o protocolo de atendimento para o tratamento desses pacientes(AU)

Currently, the treatment of primary snoring and Obstructive Sleep Apnea/Hypopnea Syndrome (OSAHS)1 through intraoral appliances (OA) has received the attention of researchers due to the proven effectiveness of these devices. The most suitable devices are jaw repositioning devices that promote mandibular advancement, moving the tissues away from the upper oropharynx, which prevents partial or total obstruction of the area. Its indication is for cases of primary snoring and mild to moderate apnea2, however it is necessary that candidates have a sufficient number of teeth with periodontal health to anchor the appliance. As it is a disease with serious systemic consequences, the treatment of OSAHS is, in essence, the responsibility of the specialist in the area, but the dental surgeon must have the knowledge to diagnose and treat, when OA is the therapeutic option. The interpretation of polysomnography, na exam that diagnoses and leads to the correct choice of treatment, and cephalometric data are the main requirements for the Dental Surgeon who proposes to treat patients with OSAHS. In this work, a questionnaire was developed and applied to dentalsurgeons from three different cities in the State of São Paulo so that it was possible to assess the knowledge of these professionals regarding the diagnosis and treatment of OSAHS. 70 Dental Surgeons were interviewed and the results showed that 70% of them are interested in working with AIOs. This group had a statistically significant relationshipwith those who stated that they had already been asked by a patient about this treatment. Regarding the creation of a specialty for this area, professional in the area of ??prosthesis and implant were more interested. And, of the total number of respondents, only 25% have already had contact with this type of device, but do not know the care protocol for the treatment of these patients(AU)

Evaluation of an open access generic 3D software for Orthodontic diagnosis and treatment planning

Aim: To evaluate the accuracy and the validity of orthodontic diagnostic measurements, as well as virtual tooth transformations using a generic open access 3D software compared to OrthoAnalyzer (3Shape) software; which was previously tested and proven for accuracy. Methods: 40 maxillary and mandibular single arch study models were duplicated and scanned using 3Shape laser scanner. The files were imported into the generic and OrthoAnalyzer software programs; where linear measurements were taken twice to investigate the accuracy of the program. To test the accuracy of the program format, they were printed, rescanned and imported into OrthAnalyzer. Finally, to investigate the accuracy of editing capabilities, linear and angular transformation procedures were performed, superimposed and printed to be rescanned and imported to OrthoAnalyzer for comparison. Results: There was no statistically significant difference between the two groups using the two software programs regarding the accuracy of the linear measurements (p>0.05). There was no statistically significant difference between the different formats among all the measurements, (p>0.05). The editing capabilities also showed no statistically significant difference (p>0.05). Conclusion: The generic 3D software (Meshmixer) was valid and accurate in cast measurements and linear and angular editing procedures. It can be used for orthodontic diagnosis and treatment planning without added costs

Congruencia entre modelos dentales impresos 3D y el archivo digital de origen: estudio in vitro comparativo de 5 impresoras 3D / Congruence between 3D printed dental models and the original digital file: comparative in vitro study of 5 3D printers

Este trabajo tuvo como objetivo conocer la fiabilidad de la impresora 3D (i3D) aditiva por Matriz de Proceso Digital de Luz (MDLP) Hellbot modelo Apolo®, a través de verificar la congruencia dimensional entre las mallas de modelos impresos (MMi) y su correspondiente archivo digital de origen (MMo), obtenido del software de planificación ortodontica Orchestrate 3D® (O3D). Para determinar su uso en odontología y sus posibilidades clínicas, fue comparada entre cinco i3D de manufactura aditiva, dos DLP, dos por estereolitografía (SLA) y una por Depósito de Material Fundido (FDM). La elección de las cinco i3D se fundamentó en su valor de mercado, intentando abarcar la mayor diversidad argentina disponible. Veinte modelos fueron impresos con cada i3D y escaneados con Escáner Intraoral (IOS) Carestream modelo 3600® (Cs3600). Las 120 MMi fueron importadas dentro del programa de ingeniería inversa Geomagic® Control X® (Cx) para su análisis 3D, consistiendo en la superposición de MMo con cada una de las MMi. Luego, una evaluación cualitativa de la desviación entre la MMi y MMo fue realizada. Un análisis estadístico cuidadoso fue realizado obteniendo como resultado comparaciones en 3d y 2d. Las coincidencias metrológicas en la superposición tridimensional permitieron un análisis exhaustivo y fácilmente reconocible a través de mapas colorimétricos. En el análisis bidimensional se plantearon planos referenciados dentariamente desde la MMo, para hacer coincidir las mediciones desde el mismo punto de partida dentaria. Los resultados fueron satisfactorios y muy alentadores. Las probabilidades de obtener rangos de variabilidad equivalentes a +/- 50µm fueron de un 40,35 % y de +/- 100µm un 71,04 %. Por lo tanto, te- niendo en cuenta las exigencias de congruencia dimensional clínicas de precisión y exactitud a las cuales es sometida nuestra profesión odontológica, se evitan problemas clínicos arrastrados por los errores dimensionales en la manufactura (Cam) (AU)

The objective of this study was to determine the reliability of the Hellbot Apollo® model additive 3D printer (i3D) by Matrix Digital Light Processing (MDLP) by verifying the dimensional congruence between the printed model meshes (MMi) and their corresponding digital source file (MMo), obtained from the Orchestrate 3D® (O3D) orthodontic planning software. A comparison was made between five i3D of additive manufacturing, two DLP, two by stereolithography (SLA), and one by Fused Material Deposition (FDM), to determine its use in dentistry and its clinical possibilities. The choice of the five i3D was based on their market value, trying to cover most of the Argentinean diversity available. Twenty models were printed with each i3D and scanned with Carestream Intraoral Scanner (IOS) model 3600® (Cs3600). The 120 MMi were imported into the reverse engineering program Geomagic® Control X® (Cx) for 3D analysis, consisting of overlaying MMo with each MMi. Then, a qualitative evaluation of the deviation between MMi and MMo. Also, a careful statistical analysis was performed, resulting in 3d and 2d comparisons. Metrological coincidences in three-dimensional overlay allowed a comprehensive and easily recognizable analysis through colorimetric maps. In the two-dimensional analysis, dentally referenced planes were proposed from the MMo, to match the measurements from the same dental starting point. The results were satisfactory and very encouraging. The probabilities of obtaining ranges of variability equivalent to +/- 50µm were 40.35 % and +/- 100µm 71.04 %. Therefore, considering the demands of clinical dimensional congruence, precision, and accuracy to which our dental profession it is subjected, clinical problems caused by dimensional errors in manufacturing (Cam) are avoided (AU)

Avaliação da acurácia dos modelos dentários digitais obtidos para cirurgia ortognática / Assessment of the accuracy of digital dental models obtained for orthognathic surgery

O objetivo deste estudo laboratorial foi avaliar a acurácia dos modelos digitais obtidos por duas técnicas de escaneamento (escâner intraoral - Itero 5d Element® - e escâner de bancada -Straumann ®) de um modelo experimental (Nacional Ossos ®) da arcada superior confeccionada em poliuretano e do modelo de gesso obtido desta arcada. Os pontos A ­ 3mm acima do elemento 17; B ­ 3mm acima do elemento 14; C ­ 3mm acima do elemento 24; D ­ 3mm acima do elemento 27; E ­ cúspide mesiovestibular do elemento 16; F - ponto de contato mais incisal entre os elementos 11 e 21; G - Cúspide mesiovestibular do elemento 26 foram utilizados como referência para as medidas realizadas. As medidas foram realizadas em um software (Geomagic®) de simulação cirúrgica e analisadas quanto a validade e precisão das técnicas de escaneamento utilizadas em todos os grupos (1 a 5). O grupo 1 corresponde ao grupo padrão-ouro; o 2 ao grupo do escaneamento com escâner intraoral do modelo de poliuretano; o 3 ao escaneamento de bancada do modelo; o 4 ao escaneamento com escâner intraoral do modelo de gesso; e 5 ao escaneamento de bancada do modelo de gesso. Na análise da validação, todas as técnicas apresentaram-se válidas quando comparadas ao grupo controle com exceção da medida FG que apresentou diferenças estatisticamente significativas (p<0,05) entre os grupos 1 e 2. A precisão foi avaliada através do índice de correlação intraclasse (CCI) e todas as técnicas apresentaram-se altamente precisas com (CCI) próximo de 1. Desta forma, conclui-se que o escâner intraoral e o escâner de bancada utilizados neste estudo foram confiáveis quando comparados ao grupo controle e que os dois modelos de escâner utilizados se apresentaram com alta precisão (AU).

The objective of this experimental study was to evaluate the accuracy of digital models generated by two scanning techniques (intraoral scanner - Itero 5d Element® - and desktop scanner -Straumann ®) of an experimental model of the upper arch (Nacional Ossos ®) made of polyurethane and the plaster model obtained from this arch. Points A ­ 3mm above element 17; B ­ 3mm above element 14; C ­ 3mm above element 24; D ­ 3mm above element 27; E ­ mesiobuccal cusp of element 16; F - most incisal point of contact between elements 11 and 21; G - Mesiobuccal cusp of element 26 were used as a reference for the measurements performed. The measurements were performed in a surgical simulation software (Geomagic ®) and analyzed for the validity and precision of the scanning techniques used in all groups (1 to 5). Group 1 corresponds to the gold standard group; 2 to the scanning group with intraoral scanner of the polyurethane model; 3 to the desktop scan of the model; 4 to intraoral scanner scanning of the plaster model; and 5 to the desktop scan of the plaster model. In the validation analysis, all techniques showed to be valid compared to the control group, except the FG measure, which showed statistically significant differences (p<0.05) between groups 1 and 2. Precision was assessed using the intraclass correlation(ICC) index, and all techniques were highly accurate with an ICC close to 1. Thus, it is concluded that the intraoral scanner and the bench scanner used in this study were reliable compared to the control group and that the two scanner models used presented themselves with high precision (AU).

Accuracy analysis of full-arch implant digital impressions when using a geometric feature / 中华口腔医学杂志

Objective: To evaluate the effect of adding a geometric feature on the accuracy of digital impressions obtained by intraoral scanners for implant restoration of edentulous jaw quantitatively. Methods: A dentiform model of the maxilla of completely edentulous arch with 6 implant analogs+scan bodies (No. 1-6) was selected as the reference model. Without geometric feature, the dentiform model was scanned by dental model scanner and repeated for 5 times as true value group. Before and after adding the geometric feature, the same operator used intraoral scanner A (Trios 3) and B (Aoralscan 2) to scan the dentiform model with the same scanning path. Each type of intraoral scanner scanned 10 times and ".stl " datas were obtained. The results were imported into reverse engineering software (Geomagic Studio 2015). The linear distances of center point of upper plane between sacn body 1 to 6 was calculated, denoted as D12, D13, D14, D15 and D16. Trueness was the absolute value subtracted from the measured value of the intraoral scanner groups and true value; precision was the absolute value of pairwise subtraction of the measured values in the intraoral scanner groups.The smaller the value, the better the accuracy or precision.With or without the feature, all scan data were statistically analyzed, and the effect of adding geometric feature on the trueness and precision of the two intraoral scanners were evaluated. Results: As for intraoral scanner A, with the feature in place, significant differences were found in D14, D15, D16 for tureness(t=2.66, 2.75, 2.95, P<0.05); the trueness for D16 decreased from (101.9±47.1) μm to (49.6±30.3) μm. On the other hand, with features on the edentulous area, the precision was significantly increased in D15 and D16 (U=378.00, 672.00, P<0.05); the precision for D15 decreased from 40.8 (45.1) μm to 13.1 (17.0) μm. As for intraoral scanner B, the trueness of D12, D13 and D14 after adding geometric features was significantly better than before (t=3.02, 2.66, U=22.00, P<0.05). With feature on the edentulous area, the trueness for D13 decreased from (116.6±41.2) μm to (70.8±35.5) μm. There was no statistical significance in the trueness of D15 and D16 with or without geometric feature (P>0.05), however, the precision of D15 and D16 after adding geometric feature was significantly better than before (U=702.00, 489.00,P<0.05). The precision of D16 decreased from 112.5 (124.7) μm to 35.9 (85.8) μm. Conclusions: The use of geometric feature in edentulous space improves the trueness and precision of the different principle intraoral scanners tested.

Accuracy of photogrammetry and conventional impression techniques for complete-arch implant rehabilitation: an in vitro comparative study / 中华口腔医学杂志

Objective: To compare the accuracy of photogrammetry and conventional impression techniques for complete-arch implant rehabilitation. Methods: An edentulous maxillary stone cast containing 8 screw-retained implant abutment replicas was derived from a 74-year-old male patient who visited the Department of Dental Implant Center, Capital Medical University School of Stomatology in September 2019. The stone cast was copied through the open-tray splinted impression, and the copied cast was used as the master cast for this study. The abutment-level impressions of master cast were made by photogrammetry (PG) and the conventional impression technique (CNV) by one attending doctor. Group PG: after which scan bodies were connected to each implant replica, a photogrammetry system was used to obtain digital impressions of the master cast (n=10); Group CNV: conventional open-tray splinted impression technique was performed to fabricate conventional definitive casts (n=10). After connecting the scan bodies onto each implant replicas, the master cast and the 10 definitive casts from group CNV were digitized with a laboratory reference scanner. All data of group PG, group CNV and mater cast were saved as ".stl" files. For all test scans and reference scan, the three-dimensional information of scan bodies were converted to implant abutment replicas using a computer aided design software (Exocad). The data of the group PG and the group CNV were respectively registered with the reference data (trueness analysis) and pairwise within group (precision analysis) for accuracy evaluation in a three-dimensional analysis software (Geomagic Control X). Results: The trueness and precision of group PG [(17.33±0.34) and (2.50±0.79) μm ] were significantly statistically better than those of group CNV [(24.30±4.16) and (26.12±4.54) μm] respectively (t=-5.29 and -34.35, P<0.001). Conclusions: For complete-arch implant abutment-level impression, photogrammetry produces significantly better accuracy than conventional impression technique.

Application evaluation of prefabricated rigid connecting bar in implants immediate impression preparation of edentulous jaw / 北京大学学报(医学版)

OBJECTIVE@#To compare the operation complexity and accuracy of traditional splint impression technique and impression technique with prefabricated rigid connecting bar system for full-arch implants-supported fixed protheses in vitro.@*METHODS@#Standard mandibular edentulous model with six implant analogs was prepared. The implants were placed at the bone level and multiunit abutments screwed into the implants. Two impression techniques were performed: the traditional splint impression technique was used in the control group, and the rigid connecting bar system was used in the test group. In the control group, impression copings were screwed into the multiunit abutments and connected with autopolymerizing acrylic resin. Open tray impression was fabricated with custom tray and polyether. In the test group, cylinders were screwed into the multiunit abutments. Prefabricated rigid bars with suitable length were selected and connected to the cylinders with small amount of autopolymerizing acrylic resin, and open tray impression was obtained. Impression procedures were repeated 6 times in each group. The working time of the two impression methods were recorded and compared. Analogs were screws into the impressions and gypsum casts were poured. The gypsum casts and the standard model were transferred to stereolithography (STL) files with model scanner. Comparative analysis of the STL files of the gypsum casts and the standard model was carried out and the root mean square (RMS) error value of the gypsum casts of the control and test groups compared with the standard model was recorded. The trueness of the two impression techniques was compared.@*RESULTS@#The work time in the test group was significantly lower than that in the control group and the difference was statistically significant [(984.5±63.3) s vs. (1 478.3±156.2) s, P < 0.05]. Compared with the standard model, the RMS error value of the implant abutments in the test group was (16.9±5.5) μm. The RMS value in the control group was (20.2±8.0) μm. The difference between the two groups was not significant (P>0.05).@*CONCLUSION@#The prefabricated rigid connecting bar can save the chair-side work time in implants immediate loading of edentulous jaw and simplify the impression process. The impression accuracy is not significantly different from the traditional impression technology. The impression technique with prefabricated rigid connecting bar system is worthy of clinical application.

Reliability of a digital system for models measurements in BBO grading: A pilot study

ABSTRACT Introduction: Currently, no method is considered effective for the evaluation of digital models in the Certification Examination of the Brazilian Board of Orthodontics (BBO), considering the parameters of the currently used manual method. Objective: Thus, the aim of this study is to verify the reliability of an evaluation method for digital models that could be used in the BBO exam, compared to the gold standard. Methods: Measurements were performed by five previously calibrated examiners. Samples of ten sets of plaster models of the final phase of orthodontic treatment were measured using a manual method (Objective Grading System, OGS). These models were digitized using a 3D scanner and exported to Geomagic Qualify software, in which the measurements were made with the proposed digital method. These measurements were repeated using five models, after fifteen days. The intra-examiner performance with this method was analyzed with a paired t-test, whereas the inter-examiner analysis was carried out with analysis of variance and Tukey's test. To compare the manual and digital methods, a paired t-test and Pearson's correlation analysis were performed. Results: A statistically significant difference was found. The results showed that, when compared to the manual method, the digital method was effective in measuring the OGS in four of the seven variables studied: Marginal Ridge, Overjet, Occlusal Contact, and Interproximal Contact. The variables Alignment, BL inclination, and Occlusal Relationship showed a great amount of dispersion in the findings. Conclusion: Further studies are needed to develop an adequate digital methodology that can be used for all OGS variables.

RESUMO Introdução: Ainda não há um método considerado eficaz para análise dos modelos digitais no exame do Board Brasileiro de Ortodontia (BBO), considerando-se os parâmetros do método manual atual. Objetivo: Assim, o presente estudo objetiva verificar a confiabilidade de um método de avaliação em modelos digitais para o exame do BBO, comparando com o padrão-ouro. Métodos: As medições foram realizadas por 5 examinadores, previamente calibrados. A amostra de 10 pares de modelos de gesso da fase final do tratamento ortodôntico foi medida no método manual (Sistema Objetivo de Avaliação, SOA). Os modelos foram digitalizados por meio de um scanner 3D e exportados para o software Geomagic Qualify, onde foram feitas as medidas no método digital proposto. As medidas foram refeitas em 5 modelos após 15 dias. A análise intraexaminador desse método foi realizada por meio do teste t pareado; já a interexaminadores, feita com ANOVA e teste de Tukey, sendo encontrada diferença estatisticamente significativa. Para a comparação dos métodos manual e digital, foram utilizados o teste t pareado e a correlação de Pearson. Resultados: Uma diferença estatisticamente significativa foi encontrada. Os resultados mostraram que, comparada ao método manual, a metodologia digital mostrou-se eficaz para medição do SOA em quatro das sete variáveis estudadas: Margem interproximal, Sobressaliência, Contato oclusal e Contato interproximal. As variáveis Alinhamento, Inclinação V-L e Relação oclusal mostraram muita dispersão nos achados. Conclusão: Mais estudos são necessários para o desenvolvimento de uma metodologia digital adequada em todas as variáveis do SOA.

Dimensional Accuracy Comparison of Physical Models Generated by Digital Impression/3D-Printing or Analog Impression/Plaster Methods / Comparación de Precisión Dimensional de Modelos Físicos Generados por Métodos de Impresión Digital/Impresión 3D o Impresión Analógica/Yeso

This study aimed to compare the trueness and precision of physical models manufactured chairside (intraoral scanner and 3D printed) or by plaster models obtained using impression with alginate or addition silicone. A full- arch stainless steel die was impressed to obtain ten physical models for each group. The models were measured in a stereomicroscope, considering four linear distances. To assess the precision accuracy, an analysis of the measurement variability was carried out, identified by the coefficients of variation and by the Levene's test to compare the groups. To analyze trueness, the data average was subtracted from the database and compared considering alpha as 5 %. Considering precision, the higher dispersion of data occurred in the models obtained with silicone impression. And for trueness, Kruskal Wallis and Dunn tests results did not indicate differences between the groups in the anteroposterior linear distances (p> 0.05). Only in anterior transverse distance obtained through TRIOS (0.31 mm), it presented lower accuracy compared to the models from silicone impression (0.13 mm); however, at transverse posterior distance, the models from silicone impression showed the lowest accuracy (p 0.05). The physical dental models obtained by digital and analog workflows showed acceptable dimensional accuracy expressed by high precision and trueness. There is no difference between the evaluated intraoral scanner systems and the impression materials for the full-arch impression.

Este estudio tuvo como objetivo comparar la veracidad y precisión de modelos físicos fabricados en la clínica dental (escáner intraoral e impreso en 3D) o por modelos de yeso obtenidos mediante impresión con alginato o silicona de adición. Una matriz de acero inoxidable de arco completo fue impresa para obtener diez modelos físicos para cada grupo. Los modelos se midieron en un estereomicroscopio, considerando cuatro distancias lineales. Se realizó un análisis de la variabilidad de la medida para evaluar la precisión, identificada por los coeficientes de variación y por la prueba de Levene para comparar los grupos. Para analizar la veracidad, el promedio de los datos se restó de la base de datos y se comparó considerando alfa como 5 %. Considerando la precisión, la mayor dispersión de datos ocurrió en los modelos obtenidos con impresión de silicona. Y para la veracidad, los resultados de las pruebas de Kruskal Wallis y Dunn no indicaron diferencias entre los grupos en las distancias lineales anteroposteriores (p> 0,05). Solo en la distancia transversal anterior obtenida mediante TRIOS (0,31 mm) presentó menor precisión en comparación con los modelos de impresión de silicona (0,13 mm); sin embargo, la distancia transversal posterior, los modelos de impresión de silicona mostraron la menor precisión (p 0,05). Los modelos dentales físicos obtenidos mediante flujos de trabajo digitales y analógicos mostraron una precisión dimensional aceptable expresada por alta precisión y veracidad. No se observó diferencia entre los sistemas de escáner intraoral evaluados y los materiales de impresión para la impresión de arco completa.

Ventajas, desventajas y perspectiva estudiantil de la tecnología del CAD/CAM en el proceso enseñanza-aprendizaje de la educación dental / Advantages, disadvantages and student perspective of CAD/CAM technology in the teaching-learning process of dental education

Introducción: La calidad del aprendizaje en odontología depende en gran medida del tipo y tiempo de práctica que se dedique con estos fines. El diseño y fabricación asistidos por computadora (CAD/CAM) que al ofrecer significativas mejoras en diversos aspectos dentro del modelado dental, advierten con reemplazar al método tradicional del modelado en yeso. Objetivo: Resumir información referente al uso de la tecnología CAD/CAM dentro del proceso enseñanza-aprendizaje de la educación dental. Métodos: Se consultaron las bases de datos MEDLINE y SciELO a través de los términos diseño asistido por computadora, CAD/CAM, enseñanza, educación dental y educación en odontología. Fueron seleccionados 36 documentos publicados a partir del año 2015. Se analizaron las categorías: definición y usos, viabilidad en la educación dental, perspectiva estudiantil, ventajas y desventajas. Análisis e integración de la información: El diseño y manufactura asistidos por computadora es un sistema tecnológico de prototipado rápido que es capaz de materializar modelos digitales diseñados en una interfaz externa, a partir de la información del escaneo realizado. Su incorporación a la educación dental se ha dado de forma dispareja y no sincronizada, debido al gasto económico requerido tanto para la compra del equipo y adaptación de las instalaciones como para la capacitación del personal pertinente. Conclusión: La aplicación del diseño y manufactura asistidos por computadora permite la creación de modelos dentales con grandes beneficios para el entrenamiento práctico. Asimismo, favorece el acercamiento hacia la estandarización de la enseñanza y la objetividad al momento de calificar el trabajo de los estudiantes realizado sobre estos modelos. La barrera económica sigue siendo una fuerte limitante para la implementación del diseño y manufactura asistidos por computadora en la educación dental, pese a ello, los estudiantes suelen presentar aceptación y una gran predisposición para su uso y aplicación(AU)

Introduction: The quality of learning in dentistry depends to a great extent on the type and time of practice devoted to these purposes. Computer-aided design and manufacturing (CAD/CAM) that, by offering significant improvements in various aspects within dental modeling, warns of replacing the traditional method of modeling in plaster. Objective: Summarize information regarding the use of CAD/CAM technology within the teaching-learning process of dental education. Methods: A search was conducted in the databases MEDLINE and SciELO using the descriptors omputer-aided design, CAD/CAM, teaching and dental education. A total 36 documents were selected, published as of the year 2015. The variables considered were definition and uses, viability in dental education, student perspective, advantages and disadvantages. Data analysis and integration: Computer-aided design and manufacturing is a rapid prototyping technological system capable of materializing digital models designed in an external interface based on scanned information. Its incorporation into dental education has been uneven and unsynchronized, due to the expenses required by the purchase of equipment, adaptation of existing facilities and training of the relevant personnel. Conclusion: Computer-aided design and manufacturing makes it possible to create dental models which are very beneficial to practical training. It is also a step forward on the road to standardization of teaching and objectivity when grading the work done by students on these models. Economic limitations continue to strongly handicap the implementation of computer-aided design and manufacturing in dental education. Despite this, students recognize its usefulness and have shown their willingness to apply it(AU)

Eficacia del cementado indirecto / Indirect bonding efficiency

La aparición de aparatología preadjustada ha colaborado en la efectividad de los tratamientos de ortodoncia, pero para que la expresión de esta aparatología se logre, es necesario una correcta colocación de los brackets y la permanencia de estos en boca durante todo el tratamiento. La precisión en la colocación mejora con la técnica de cementado indirecta, ya que permite el acceso a las zonas posteriores, a lugares donde se ve disminuida la visión y además disminuye la condensación de aliento y contaminación salival. Si bien esta técnica requiere tiempo extra de laboratorio, es más rápida en la etapa clínica (AU)

Usability of free software used for visualization and measurement of digital orthodontic models

The aim of this study was to evaluate the usability of the free software available that allow visualization and measurement of orthodontic digital models. 80 graduate students of orthodontics were asked to perform pre-defined tasks in a digital model through 3D Viewer ® and 3D-Tool ® software. The success in accomplishing the tasks and the time spent were recorded. To end, each participant answered a questionnaire to express their satisfaction regarding the software. There were no statistically significant difference between the software when compared to the accomplishment rates of tasks and the time spent by participants on each one. The software were evaluated as "slightly satisfactory" in several criteria. There is scope for optimization of orthodontic software by manufacturers since lack of their interface usability can discourage orthodontists' adherence to new resources that could provide benefits to their daily routine, even if they are freely available.

Extended-pour and conventional alginates: effect of storage time on dimensional accuracy and maintenance of details

ABSTRACT Objective: This study aimed to evaluate the dimensional stability and maintenance of details of conventional and high stability alginates up to 5-day storage. Methods: Two types of alginates were selected (n=10) for this study, conventional (Hydrogum) and high stability alginates (Hydrogum 5), which were produced with the aid of a cylindrical metal block and a ring-shaped metal mold (Specifications 18, 19, and 25, ANSI/ADA). Ten images were obtained from the molds for the dimensional stability test, which were taken immediately after their production and at each different storage periods (15 min, 24 h, 48 h, 72 h, 96 h, and 120 h) by a digital camera. The specimens were kept hermetically sealed in plastic bags (23°C) and then used to obtain 140 (n=70) dental stone models, used in the detail reproduction test, in which the angular accuracy of three grooves (20 µm, 50 µm, and 75 µm) was observed at each period. The details reproduction accuracy was classified using a predetermined score classification. Measurements of dimensional changes were made in the Corel DRAW X6 program. The data were submitted to the Student's t-test (α?#8197;= 0.05). Results: A statistically significant difference concerning the size of the matrix was observed after 24h for both alginates, and a statistically significant negative linear dimensional change (contraction) was verified after 24 h of storage (1.52% for the high stability alginate, and 1.32% for the conventional alginate). The high stability alginate kept the full details for 72 hours, while the conventional alginate, for 24 h. Both alginates reproduced the 75 µm groove at all storage periods. Conclusion: Impressions made with both alginates presented satisfactory clinical results when the alginates were immediately poured.

RESUMO Objetivo: O presente estudo teve como objetivo avaliar a estabilidade dimensional e manutenção de detalhes de alginatos convencionais e de alta estabilidade por até 5 dias de armazenamento. Métodos: Para esse estudo, foram selecionados dois tipos de alginatos: convencional (Hydrogum) (n = 10) e de alta estabilidade (Hydrogum 5) (n = 10), sendo produzidos com o auxílio de um bloco metálico cilíndrico e um molde metálico em forma de anel (especificações 18, 19 e 25, ANSI/ADA). Para o teste de estabilidade dimensional, dez imagens foram obtidas imediatamente e para cada tempo de armazenamento (15 min, 24, 48, 72, 96 e 120 horas), realizadas por câmera digital. As amostras foram mantidas hermeticamente fechadas em sacos plásticos (23°C). Para o teste de reprodução de detalhes, as amostras foram utilizadas para obter 140 (n = 70 por grupo) modelos de gesso, sendo observada a precisão angular de três sulcos (20 µm, 50 µm e 75 µm) para cada período. A precisão da reprodução de detalhes foi classificada usando uma classificação de pontuação predeterminada. As medições das mudanças dimensionais foram feitas no programa Corel DRAW X6. Os dados foram submetidos ao teste t de Student (α = 0,05). Resultados: Foi observada diferença estatística em relação à matriz após 24h para ambos os alginatos. Uma mudança dimensional linear negativa estatisticamente significativa (contração) foi verificada após 24 h de armazenamento (1,52% para alginato de alta estabilidade; 1,32% para alginato convencional). O alginato de alta estabilidade manteve os detalhes completos por até 72 horas, enquanto o alginato convencional, por 24 horas. Os alginatos reproduziram o sulco de 75 µm para todos os períodos. Conclusão: As impressões feitas com ambos os alginatos devem ser imediatamente vazadas para se ter resultados clínicos satisfatórios.