ABSTRACT
STATEMENT OF PROBLEM: Data on the accuracy of printed casts from complete-arch digital implant scans are lacking. PURPOSE: The purpose of this in vitro study was to compare the 3D accuracy of printed casts from a complete-arch digital implant intraoral scan with stone casts from conventional impressions. MATERIAL AND METHODS: An edentulous mandibular cast with 4 multiunit abutments with adequate anteroposterior spread was used as the master cast. Digital scans (n=25) were made by using a white light intraoral scanner (IOS). The generated standard tessellation language (STL) data sets were imported into a computer-assisted design (CAD) software program to generate complete-arch implant casts through 3D printing technology. The 25 printed casts and the mandibular master cast were further digitized by using a laboratory reference scanner (Activity 880; Smart Optics). These STL data sets were superimposed on the digitized master cast in a metrology software program (Geomagic Control X) for virtual analysis. The root mean square (RMS) error and the average offset were measured. RESULTS: When compared with the master cast, the printed casts had a mean ±standard deviation RMS error of 59 ±16 µm (95% CI: 53, 66). The maximum RMS error reached 98 µm. The average offsets were all negative, with a significant difference compared with zero (P<.001). CONCLUSIONS: The implant 3D deviations of the printed casts from complete-arch digital scans had statistically significant differences compared with those of the master cast but may still be within the acceptable range for clinical application.
Subject(s)
Dental Implants , Dental Impression Technique , Computer-Aided Design , Imaging, Three-Dimensional , Models, Dental , Printing, Three-Dimensional , WorkflowABSTRACT
OBJECTIVES: The aim of this in vitro study was to compare the accuracy of printed implant casts from digital impressions with two intra-oral scanners (IOS) to stone casts from conventional impressions. The hypothesis was that printed casts would be more accurate than stone casts from conventional impressions. MATERIALS AND METHODS: A mandibular stone cast with Kennedy class II edentulism was fabricated using two internal connection tissue-level implants at 30 degrees to each other (Replace Select RP, Nobel Biocare) to serve as master. Digital impressions (n = 10) were made with the white light (WL) and Active Wavefront Sampling technology (AWST) IOS. The resultant standard tessellation language (STL) datasets were used to print implant casts through stereolithography (SLA) prototyping. The conventional casts (n = 10) were produced with splinted open tray impression technique and polyether material in type IV stone. The master cast and all groups were digitized with lab reference scanner. The test groups STL datasets were superimposed to master cast STL in inspection software (Geomagic control 2015) to calculate root-mean-square error. RESULTS: The conventional, WL IOS and AWST IOS groups had mean values of 53.49 µm (SD 9.47), 108.09 µm (SD 9.59) and 120.39 µm (SD 5.91), respectively. The Shapiro-Wilk test showed no evidence of nonnormality (p = 0.131) and Levene's test showed no evidence of heterogeneity of variance (p = 0.518). The one-way ANOVA demonstrated a statistically significant difference (p < 0.001). Tukey's honest significant difference (HSD) showed statistically significant differences between all groups: for the comparison of AWST IOS and WL IOS, the p-value was 0.009, and the p-values of the other post hoc tests were <0.001. CONCLUSION: Printed casts generated from digital impressions for partially edentulous posterior mandibular arches had inferior accuracy to conventional stone casts fabricated from splinted open tray impressions. The printed casts from WL IOS had better accuracy compared to AWST IOS.
Subject(s)
Computer-Aided Design , Dental Casting Technique , Dental Impression Technique , Analysis of Variance , Dental Implants , Dental Impression Materials , Humans , In Vitro Techniques , Jaw, Edentulous, Partially , Mandible , Models, DentalABSTRACT
Monolithic ceramics have been introduced in dentistry to help reduce technical complications reported with implant-supported metal-resin hybrid prostheses. This clinical report describes the maintenance and technical complications that occurred during a full-mouth implant rehabilitation using different prosthetic materials over a 7-year period. During the course of 4 of those years, multiple technical complications were encountered with the metal-resin hybrid prostheses, prompting the need for increased maintenance.New prostheses were inserted with screw-retained titanium frameworks and individually cemented single crowns, and subsequently no technical complications were encountered after 2 years of follow-up.
