Technical note on introducing a digital workflow for newborns with craniofacial anomalies based on intraoral scans - part II: 3D printed Tübingen palatal plate prototype for newborns with Robin sequence

Background

Orthodontic treatment of newborns and infants with Robin-Sequence using the Tübingen Palatal Plate (TPP) is a complex procedure that could benefit from simplification through digitalization. The design of the velar extension (spur) and the palatal base determines the success of the treatment. Therefore, a prototype must be produced and inserted under endoscopic supervision in order to determine the appropriate shape, length and position of the spur. This technical note demonstrates a fully digital workflow for the design and manufacturing of a functional TPP prototype, based on an intraoral scan. This prototype can be altered and individualized digitally for each patient. After the shape and position of the spur have been optimized, the prototype is duplicated using a silicone mold. Then the definitive TPP is manufactured and inserted. We aim to present a workflow which facilitates the fitting procedure and does not require a conventional impression or a physical model to create the appliance.

Methods

As described in part I of this series, the intraoral scan is performed using the 3Shape TRIOS3 scanner and its corresponding acquisition software. The virtual model is rendered in the 3Shape ortho appliance designer and the base of the palatal plate is designed in the 3Shape dental designer. The palatal plate and the virtual model are then imported into Autodesk Meshmixer and a standardized spur is positioned and merged with the base. The TPP is exported in Standard Tessellation Language (STL) format and manufactured on a W2P Solflex 170 DLP printer using VOCO VPrint Splint material (MDR Class IIa).

Results

Based on an intraoral scan, the TPP prototype could be successfully manufactured and proved suitable for the patients’ treatment.

Conclusion

The new digital workflow for the design of the TPP can been successfully implemented into daily clinical routine in our facility. Patients could be alleviated from having to undergo conventional impression procedures and fitting of the TPP could be facilitated by producing multiple functional prototypes for endoscopic evaluation. Through rapid prototyping, the expenditure of the fitting process was reduced, which makes the TPP therapy more efficient and accessible to a wider range of clinicians.

Technical note on introducing a digital workflow for newborns with craniofacial anomalies based on intraoral scans - part I: 3D printed and milled palatal stimulation plate for trisomy 21

Background

Advanced digital workflows in orthodontics and dentistry often require a combination of different software solutions to create patient appliances, which may be a complex and time-consuming process. The main objective of this technical note is to discuss treatment of craniofacial anomalies using digital technologies. We present a fully digital, linear workflow for manufacturing palatal plates for infants with craniofacial anomalies based on intraoral scanning. Switching to intraoral scanning in infant care is advantageous as taking conventional impressions carries the risk of impression material aspiration and/or infections caused by material remaining in the oronasal cavity.

Material and methods

The fully digital linear workflow presented in this technical note can be used to design and manufacture palatal plates for cleft palate patients as well as infants with functional disorders. We describe the workflow implemented in an infant with trisomy 21. The maxilla was registered using a digital scanner and a stimulation plate was created using dental CAD software and an individual impression tray module on a virtual model. Plates were manufactured using both additive and subtractive methods. Methacrylate based light curing resin and Poly-Ether-Ether-Ketone were the materials used.

Results

The palatal area was successfully scanned to create a virtual model. The plates fitted well onto the palatal area. Manual post-processing was necessary to optimize a functional ridge along the vestibular fold and remove support structures from the additively manufactured plate as well as the milled plate produced from a blank. The additively manufactured plate fitted better than the milled one.

Conclusion

Implementing a fully digital linear workflow into clinical routine for treatment of neonates and infants with craniofacial disorders is feasible. The software solution presented here is suitable for this purpose and does not require additional software for the design. This is the key advantage of this workflow, which makes digital treatment accessible to all clinicians who want to deal with digital technology. Whether additive or subtractive manufacturing is preferred depends on the appliance material of choice and influences the fit of the appliance.

Comparative evaluation of topographical data of dental implant surfaces applying optical interferometry and scanning electron microscopy

OBJECTIVE

Comparability of topographical data of implant surfaces in literature is low and their clinical relevance often equivocal. The aim of this study was to investigate the ability of scanning electron microscopy and optical interferometry to assess statistically similar 3-dimensional roughness parameter results and to evaluate these data based on predefined criteria regarded relevant for a favorable biological response.

METHODS

Four different commercial dental screw-type implants (NanoTite Certain Prevail, TiUnite Brånemark Mk III, XiVE S Plus and SLA Standard Plus) were analyzed by stereo scanning electron microscopy and white light interferometry. Surface height, spatial and hybrid roughness parameters (Sa, Sz, Ssk, Sku, Sal, Str, Sdr) were assessed from raw and filtered data (Gaussian 50μm and 5μm cut-off-filters), respectively. Data were statistically compared by one-way ANOVA and Tukey-Kramer post-hoc test. For a clinically relevant interpretation, a categorizing evaluation approach was used based on predefined threshold criteria for each roughness parameter.

RESULTS

The two methods exhibited predominantly statistical differences. Dependent on roughness parameters and filter settings, both methods showed variations in rankings of the implant surfaces and differed in their ability to discriminate the different topographies. Overall, the analyses revealed scale-dependent roughness data. Compared to the pure statistical approach, the categorizing evaluation resulted in much more similarities between the two methods.

SIGNIFICANCE

This study suggests to reconsider current approaches for the topographical evaluation of implant surfaces and to further seek after proper experimental settings. Furthermore, the specific role of different roughness parameters for the bioresponse has to be studied in detail in order to better define clinically relevant, scale-dependent and parameter-specific thresholds and ranges.