Alexander Xepapadeas

Mr. Alexander Xepapadeas

Department of Orthodontics in the University Centre of Dentistry, Oral Medicine and Maxillofacial Surgery within the University Hospital Tübingen
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 September 2021 in European Journal of Orthodontics
Verified
Journal Article
Closed access
CWChristina Weise
Christina Weise
KFKarin Frank
Karin Frank
CWCornelia Wiechers
Cornelia Wiechers
HWHannes Weise
Hannes Weise
SRSiegmar Reinert
Siegmar Reinert
AXAlexander Xepapadeas
Alexander Xepapadeas
Summary: Objective: The aim of this study was to evaluate intraoral scanning (IOS) in infants, neonates, and small children with craniofacial anomalies for its feasibility, scanning duration, and success rate. Impression taking in vulnerable patients can be potentially life-threatening, with the risk of airway obstruction and aspiration of impression material. The advantage of increasingly digitalized dentistry is demonstrated. Materials and methods: IOS was captured with the Trios 3® (3Shape, Copenhagen, Denmark) intraoral scanner. The underlying disorders were divided into cleft lip and palate (CLP), Trisomy 21 (T21), Robin Sequence (RS), Treacher Collins syndrome (TC), and isolated mandibular retrognathia (MR). Scan data were analysed by scanning duration, number of images, possible correlations of these factors with the different craniofacial disorders, patient age, and relationship between first and subsequent scans. Clinical experiences with the repeated digital impressions are described. Results: Patient data of 141 scans in 83 patients were analysed within an 11-month period. Patients had a median age of 137 days. Median scanning duration was 138 seconds, resulting in a median of 352 images. There was a statistically significant difference in scanning duration (P = 0.001) between infants and neonates. IOS took longest in patients with CLP (537 seconds) and shortest in T21 patients (21 seconds), although there was no statistically significant difference between aetiologies. There was no statistically significant difference between first and subsequent scans in scanning duration. In four cases the IOS had to be repeated, and one patient ultimately required conventional impression taking (all CLP patients; success rate 94%). No severe adverse events occurred. Conclusion: IOS is a fast, safe, and feasible procedure for neonates, small children, and infants with craniofacial malformations. One special challenge for both technician and user was identified in patients with CLP, though implementing this new approach of digital impression taking was otherwise found to be highly successful in everyday clinical routine.

16 June 2020 in BMC Oral Health
Verified
Journal Article
Open access
PDF file
AXAlexander Xepapadeas
Alexander Xepapadeas
CWC. Weise
C. Weise
KFK. Frank
K. Frank
SSS. Spintzyk
S. Spintzyk
CPC. F. Poets
C. F. Poets
BKB. Koos
B. Koos
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.

12 January 2021 in Materials
Verified
Journal Article
Open access
PDF file
Maite AretxabaletaMaite Aretxabaleta
Maite Aretxabaleta
AXAlexander Xepapadeas
Alexander Xepapadeas
CPChristian F. Poets
Christian F. Poets
CPChristian F. Poets
Christian F. Poets
SSSebastian Spintzyk
Sebastian Spintzyk
CAD/CAM technologies and materials have the potential to improve the treatment of Robin Sequence with orthodontic appliances (Tübingen palatal plate, TPP). However, studies on the provided suitability and safety are lacking. The present study evaluates CAD/CAM technologies and materials for implementation into the workflow for producing these orthodontic appliances (TPPs), manufactured by different techniques and materials: additive manufacturing (AM) and subtractive manufacturing (SM) technologies vs. conventional manufacturing. The fracture load was obtained in a universal testing machine, and the breaking behavior of each bunch, as well as the necessity of adding a safety wire, was evaluated. The minimum fracture load was used to calculate the safety factor (SF) provided by each material. Secondary factors included manufacturing time, material cost and reproducibility. Dental LT clear showed the highest fracture load and best breaking behavior among AM materials. The highest fracture load and safety factor were obtained with Smile polyether ether ketone (PEEK). For the prototyping stage, the use of a Freeprint tray (SF = 114.145) is recommended. For final manufacturing, either the cost-effective approach, Dental LT clear (SF = 232.13%), or the safest but most expensive approach, Smile PEEK (SF = 491.48%), can be recommended.

23 July 2021 in Materials
Verified
Journal Article
Open access
PDF file
Maite AretxabaletaMaite Aretxabaleta
Maite Aretxabaleta
AUAlexey Unkovskiy
Alexey Unkovskiy
BKBernd Koos
Bernd Koos
SSSebastian Spintzyk
Sebastian Spintzyk
AXAlexander Xepapadeas
Alexander Xepapadeas
Different approaches for digital workflows have already been presented for their use in palatal plates for newborns and infants. However, there is no evidence on the accuracy of CAD/CAM manufactured orthodontic appliances for this kind of application. This study evaluates trueness and precision provided by different CAM technologies and materials for these appliances. Samples of a standard palatal stimulation plate were manufactured using stereolithography (SLA), direct light processing (DLP) and subtractive manufacturing (SM). The effect of material (for SM) and layer thickness (for DLP) were also investigated. Specimens were digitized with a laboratory scanner (D2000, 3Shape) and analyzed with a 3D inspection software (Geomagic Control X, 3D systems). For quantitative analysis, differences between 3D datasets were measured using root mean square (RMS) error values for trueness and precision. For qualitative analysis, color maps were generated to detect locations of deviations within each sample. SM showed higher trueness and precision than AM technologies. Reducing layer thickness in DLP did not significantly increase accuracy, but prolonged manufacturing time. All materials and technologies met the clinically acceptable range and are appropriate for their use. DLP with 100 µm layer thickness showed the highest efficiency, obtaining high trueness and precision within the lowest manufacturing time.

Verified
Journal Article
Open access
PDF file
CWChristina Weismann
Christina Weismann
AXAlexander Xepapadeas
Alexander Xepapadeas
MBMarit Bockstedte
Marit Bockstedte
BKBernd Koos
Bernd Koos
MKMichael Krimmel
Michael Krimmel
Maite AretxabaletaMaite Aretxabaleta
Maite Aretxabaleta
Deciding on the implementation or modification of steps in daily clinical care is a nuanced process that demands careful evaluation. This is crucial not only for selecting the most appropriate solution but also for achieving the best treatment outcome. Thus, implementing a workflow for treating cleft lip and/or palate patients with a presurgical orthodontic cleft-covering plate needs to consider objective factors, prioritized from most to least important: safety and quality level, user-friendliness, feasibility, and, finally, efficiency and cost. The goal of this workflow is to integrate CAD/CAM technologies into daily clinical routine to enhance technical and clinical efficiency, reduce the burden of cleft care, and simplify the implementation of these technologies in other facilities. To achieve this, a methodology based on intraoral scanning and additive manufacturing is employed to produce patient-specific passive palatal plates. The approach describes possible pitfalls and their resolution within the routine of a cleft centre, along with an exemplary case scenario. Comparative analysis between the digital workflow and the conventional process demonstrated the digital approach to be safer, higher in quality, more user-friendly, feasible, and cost- and time-effective than the conventional process.

Verified
Journal Article
Open access
PDF file
MBMarit Bockstedte
Marit Bockstedte
AXAlexander Xepapadeas
Alexander Xepapadeas
SSSebastian Spintzyk
Sebastian Spintzyk
CPChristian F. Poets
Christian F. Poets
BKBernd Koos
Bernd Koos
Maite AretxabaletaMaite Aretxabaleta
Maite Aretxabaleta
The objective of this study was to present a methodology and manufacturing workflow for non-invasive ventilation interfaces (NIV) for neonates and small infants. It aimed to procure a fast and feasible solution for personalized NIV produced in-house with the aim of improving fit and comfort for the patient. Three-dimensional scans were obtained by means of an intraoral (Trios 3) and a facial scanner (3dMd Flex System). Fusion 360 3D-modelling software was employed to automatize the design of the masks and their respective casting molds. These molds were additively manufactured by stereolithography (SLA) and fused filament fabrication (FFF) technologies. Silicone was poured into the molds to produce the medical device. In this way, patient individualized oronasal and nasal masks were produced. An automated design workflow and use of additive manufacturing enabled a fast and feasible procedure. Despite the cost for individualization likely being higher than for standard masks, a user-friendly workflow for in-house manufacturing of these medical appliances proved to have potential for improving NIV in neonates and infants, as well as increasing comfort.