Accuracy of Different Head Movements of Intraoral Scanner in Full Arch of Both Maxilla and Mandible

This in vitro study aimed to compare the accuracy of maxilla and mandible full-arch scans from an intraoral scanner via one scan path with six different head movements. Standard maxilla and mandible models via holder were set in a dental chair to simulate position and posture. The reference models’ standard tessellation language (STL) files were formatted via desktop scanner, and operative models’ files were obtained via IOS TRIOS 3 Pod as superimposed by Exocad CAD software. The same scan path with six head movements (Linear, Circle, Wave, 8-figure, S-figure, and A-P) were designed to scan 10 times per jaw, and a total of 120 scan files were then compared with reference files. The data were recorded and deviations of both occlusal and B-L sides were compared, with statistical analysis being performed by one-way analysis of variance (ANOVA) and post hoc comparisons with Tukey test. The trueness of optical impression for full-arch via one path with six head movements differed from maxilla and mandible and depended on the different movements (p < 0.05). In the same path, peak deviation was found at the turning points for left central incisor, left first premolar, left second molar, and right second molar in maxilla, and for right first premolar, second molar, and left second molar in the mandible. The 8-figure movement showed the highest deviation (0.128 ± 0.086 mm) in the maxilla and (0.105 ± 0.069 mm) in the mandible. The Linear movement presented the lowest deviation (0.096 ± 0.07 mm) in the maxilla while the Circle movement presented the lowest deviation (0.073 ± 0.041 mm) in the mandible, with the 8-figure movement showing the worst precision among six movements. In the maxilla, the S- and 8-figure movements were not recommended, while the Linear and Circle movements showed high trueness. In the mandible, the 8-figure movement was not recommended, while the other five presented similar lower deviations.

A New Proposal: A Digital Flow for the Construction of a Haas-Inspired Rapid Maxillary Expander (HIRME)

Maxillary expansion is a common orthodontic treatment used for the correction of posterior crossbite resulting from reduced maxillary width. Transverse maxillomandibular discrepancies are a major cause of several malocclusions and may be corrected in different manners; in particular, the rapid maxillary expansion (RME) performed in the early mixed dentition has now become a routine procedure in orthodontic practice. The aim of this study is to propose a procedure that reduces the patient cooperation as well as the lab work required in preparing a customized Haas-inspired rapid maxillary expander (HIRME) that can be anchored to deciduous teeth and can be utilized in mixed dentition with tubes on the molars and hooks and brackets on the canines. This article thus presents an expander that is completely digitally developed, from the first moment of taking the impression with an optical scanner to the final solidification phase by the use of a 3D printer. This digital flow takes place in a CAD environment and it starts with the creation of the appliance on the optical impression; this design is then exported as an stl extension and is sent to the print service to obtain a solid model of the device through a laser sintering process. This “rough” device goes through a post-processing procedure; finally, a commercial expansion screw is laser-welded. This expander has all the advantages of a cast-metal Haas-type RME that rests on deciduous teeth; moreover, it has the characteristic of being developed with a completely digitized and individualized process, for the mouth of the young patient, as well as being made completely of cobalt-chrome, thus ensuring greater adaptability and stability in the patient’s mouth.

Evaluation of the Accuracy of an Intraoral Scanner: An Update on the Omnicam

Computerized optical impression making is one of the most exciting topics in dentistry today. Therefore, it is very important to know how accurate these devices are. Purpose: To investigate the influence of a software update of an intraoral scanner. Materials and Methods: Accuracy was tested in terms of trueness and precision. An acrylic model was scanned with an industrial scanner. The dataset was used as reference for the evaluation of the CEREC AC Omnicam datasets and statistical analyses implemented. Results: Trueness and precision values very significantly smaller with the latest software version as opposed to the previous version. Conclusion: Within the limits of the present study, the investigated intraoral scanner meets the highest standards in terms of trueness and precision. The authors strongly recommend to not use software other than the proprietary workflows to export files to the open STL file format.