RESUMEN
This in-vitro study was designed to investigate whether conventionally produced casts and printed casts for orthodontic purposes show comparable full-arch accuracy. To produce casts, either a conventional impression or a digital data set is needed. A fully dentate all ceramic master cast was digitized with an industrial scanner to obtain a digital reference cast [REF]. Intraoral scans [IOS] and alginate impressions were taken from the master cast so that ten printed and ten gypsum casts were obtained. The printed casts [DLP] were digitized by an industrial scanner and as well as the gypsum casts [GYPSUM]. The following absolute mean trueness evaluations by superimposition were accomplished: [REF vs. GYPSUM]; [REF vs. DLP]; [REF vs. IOS]; [IOS vs. DLP]. For precision analysis the data sets of [GYPSUM], [IOS] and [DLP] were available. The absolute mean trueness values were 68 µm ± 15 µm for [REF vs. GYPSUM], 46 µm ± 4 µm for [REF vs. DLP], 20 µm ± 2 µm for [REF vs. IOS] and 41 µm ± 4 µm for [IOS vs. DLP]. [REF vs. GYPSUM] and [REF vs. DLP], [REF vs. IOS], [REF vs. DLP] and [IOS vs. DLP] showed statistically significant differences. The precision values were 56 µm ± 17 µm for [GYPSUM], 25 µm ± 9 µm for [DLP] and 12 µm ± 2 µm for [IOS] and differed significantly among each other. In the present study the print workflow revealed superior results in comparison to the conventional workflow. Due to contrary deviations in the [REF vs. IOS] and the [IOS vs. DLP] data sets the overall trueness deviations was enhanced.
Asunto(s)
Diseño Asistido por Computadora , Imagenología Tridimensional , Flujo de Trabajo , Sulfato de Calcio , Modelos Dentales , Técnica de Impresión DentalRESUMEN
AIM: To test four different measurement methods to evaluate deviations between planned and actual implant positions within a digital workflow applying 3D-printed surgical guides. MATERIALS AND METHODS: A fully digital workflow was applied to simulate the single implant insertion to replace a maxillary missing central incisor and first molar in 10 gypsum casts (n = 10). Surgical guides (n = 10 per site) were printed by digital light processing for implant bed preparation and implant insertion. Four methods were used to analyze 3D deviations between the planned (target) and achieved implant positions: Methods 1 and 2 used an automated computer program (ACP) to assess deviations between the initial planning file and a file that represented the actual implant position either by the implant bed [ACP_BED] or by the inserted implant [ACP_IMP]. For Method 3, a standard tessellation language dataset representing the actual implant position was used and equipped with reference planes. This dataset was registered with the target planning, allowing manual measurements [MAN_MEAS]. Method 4 used a reverse engineering approach based on 3D high-resolution scans [REVERSE]. RESULTS: Mean 3D deviations, including for anterior and posterior implant sites, ranged between 0.26 ± 0.11 mm [REVERSE] and 0.40 ± 0.09 mm [ACP_BED] at the implant shoulder, between 0.52 ± 0.24 mm [REVERSE] and 0.91 ± 0.24 mm [ACP_BED] at the implant apex, and between 1.68 and 2.35 degrees in angular deviation. Implant sites did not differ significantly, while some of the evaluation methods differed for shoulder and apex. CONCLUSION: [REVERSE] revealed the smallest deviations between planned and actual implant position. 3D implant deviations were comparable with findings in the literature or even lower.