Dimensional accuracy of different impression techniques of partially edentulous mandibular arch

Abstract

ObjectiveThe purpose of this in vitro study was to assess and compare the dimensional accuracy of three impression techniques: 1-step putty/light-body, 2-step putty/light-body, and the monophase technique. Methods A partially edentulous standard stainless steel mandibular arch cast with reference points on the teeth was used to make the impressions. The anteroposterior and transverse distances were measured. All impressions were made with a polyvinyl siloxane using stock metallic (1-and 2-step putty/light-body techniques) or acrylic resin (monophase technique) trays. The monophase impressions were made using a light-body material and the 1-and 2-step putty/light-body impressions with putty and light-body materials. After impression procedures, the accuracy of each technique was assessed measuring the stone casts (n = 5) poured from the impressions using a microscope at 30x magnification and at 0.5 µm accuracy. The data were analyzed statistically using 2-way ANOVA and Tukey's test (p<0.05). Results Stone casts made by all techniques had significantly negative linear changes (shrinkage). The anteroposterior distances showed more dimensional changes than the transverse distances. The edentulous side showed more shrinkage than the anteroposterior side. ConclusionNo differences between the impression techniques were found, but significant dimensional changes were observed.

Estabilidade dimensional de moldes obtidos com alginato de armazenamento tardio

“…Os resultados obtidos mostram que os valores de estabilidade dimensional das amostras estão abaixo de 100%. Ou seja, mesmo a uma umidade relativa de 100%, conforme preconizado em diversos estudos 11,14,15 , as amostras sofreram o processo de sinérese inerente ao material utilizado, uma vez que alginato dental contém aproximadamente 70% de água. Devido a este alto teor de água, o alginato está sujeito a sinérese ou perda de água.…”

Evaluation of dimensional stability and details reproduction of alginate molds storage in different times and temperature

“…Another limitation of the present study is that in order to verify the influence of each study factor there is a control of other variables that influence the quality of the molds, such as pressure applied during molding, removal of the tray in single movement avoiding tilting movements, standardization of the temperature throughout the impression procedure, minimizing thermal changes occurring between buccal and room temperature, and throughout the mold storage [4][5][6]8,15]. Routinely these dimensional stability values for alginates could be different from the results of this study, since it is impossible to control all of these variables.…”

“…However, the quality of details reproduction is important in dental practice, since alginate is the impression material used for several initial prosthetic, orthodontic and restorative procedures. Any imprecision in this step could compromise the whole rehabilitation treatment, interfering with the prognosis of the clinical treatment [15,20,21].…”

Análise comparativa da exatidão de modelos para próteses fixas obtidos por fluxo analógico e digital

“…Medidas lineares tem sido amplamente utilizada para avaliar a exatidão de modelos odontológicos de gesso (CAPUTI; VARVARA, 2008;FARIA et al, 2009;VITTI et al, 2017) e modelos obtidos por manufatura aditiva (CHOI et al, 2002;KEATING et al, 2008;TANCU et al, 2019) KU, 2003). Devido a automatização dos procedimentos de alinhamento e cálculo da discrepância, as comparações 3D apresentam menor chance de incorporação de viés por erro de medições manuais (JIN et al, 2019;ZHANG et al, 2019).…”