Hans-Florian Zeilhofer

Hans-Florian Zeilhofer


Research Focus & Metrics

Academic Career Length

30Years (1997-Present)

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

Representative Publications

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17 March 2020 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
BMBilal Msallem
Bilal Msallem
Neha SharmaNeha Sharma
Neha Sharma
SCShuaishuai Cao
Shuaishuai Cao
FHFlorian S. Halbeisen
Florian S. Halbeisen
HZHans-Florian Zeilhofer
Hans-Florian Zeilhofer
Florian Markus ThieringerFlorian Markus Thieringer
Florian Markus Thieringer
With the rapid progression of additive manufacturing and the emergence of new 3D printing technologies, accuracy assessment is mostly being performed on isosymmetric-shaped test bodies. However, the accuracy of anatomic models can vary. The dimensional accuracy of root mean square values in terms of trueness and precision of 50 mandibular replicas, printed with five common printing technologies, were evaluated. The highest trueness was found for the selective laser sintering printer (0.11 ± 0.016 mm), followed by a binder jetting printer (0.14 ± 0.02 mm), and a fused filament fabrication printer (0.16 ± 0.009 mm). However, highest precision was identified for the fused filament fabrication printer (0.05 ± 0.005 mm) whereas other printers had marginally lower values. Despite the statistically significance (p < 0.001), these differences can be considered clinically insignificant. These findings demonstrate that all 3D printing technologies create models with satisfactory dimensional accuracy for surgical use. Since satisfactory results in terms of accuracy can be reached with most technologies, the choice should be more strongly based on the printing materials, the intended use, and the overall budget. The simplest printing technology (fused filament fabrication) always scored high and thus is a reliable choice for most purposes.

Verified
Journal Article
Open access
PDF file
Neha SharmaNeha Sharma
Neha Sharma
SASoheila Aghlmandi
Soheila Aghlmandi
FDFederico Dalcanale
Federico Dalcanale
Daniel SeilerDaniel Seiler
Daniel Seiler
HZHans-Florian Zeilhofer
Hans-Florian Zeilhofer
Florian Markus ThieringerFlorian Markus Thieringer
Florian Markus Thieringer
Recent advancements in medical imaging, virtual surgical planning (VSP), and three-dimensional (3D) printing have potentially changed how today’s craniomaxillofacial surgeons use patient information for customized treatments. Over the years, polyetheretherketone (PEEK) has emerged as the biomaterial of choice to reconstruct craniofacial defects. With advancements in additive manufacturing (AM) systems, prospects for the point-of-care (POC) 3D printing of PEEK patient-specific implants (PSIs) have emerged. Consequently, investigating the clinical reliability of POC-manufactured PEEK implants has become a necessary endeavor. Therefore, this paper aims to provide a quantitative assessment of POC-manufactured, 3D-printed PEEK PSIs for cranial reconstruction through characterization of the geometrical, morphological, and biomechanical aspects of the in-hospital 3D-printed PEEK cranial implants. The study results revealed that the printed customized cranial implants had high dimensional accuracy and repeatability, displaying clinically acceptable morphologic similarity concerning fit and contours continuity. From a biomechanical standpoint, it was noticed that the tested implants had variable peak load values with discrete fracture patterns and failed at a mean (SD) peak load of 798.38 ± 211.45 N. In conclusion, the results of this preclinical study are in line with cranial implant expectations; however, specific attributes have scope for further improvements.

1 December 2015 in British Journal of Oral and Maxillofacial Surgery
Verified
Journal Article
Closed access
KBK.-W. Baek
K.-W. Baek
WDW. Deibel
W. Deibel
DMD. Marinov
D. Marinov
MGM. Griessen
M. Griessen
ABA. Bruno
A. Bruno
PJPh. Juergens
Ph. Juergens

24 January 2021 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
MUMatthias Ureel
Matthias Ureel
MAMarcello Augello
Marcello Augello
DHDaniel Holzinger
Daniel Holzinger
TWTobias Wilken
Tobias Wilken
BBBritt-Isabelle Berg
Britt-Isabelle Berg
AMAndreas A. Mueller
Andreas A. Mueller
Background: In order to overcome the geometrical and physical limitations of conventional rotating and piezosurgery instruments used to perform bone osteotomies, as well as the difficulties in translating digital planning to the operating room, a stand-alone robot-guided laser system has been developed by Advanced Osteotomy Tools, a Swiss start-up company. We present our experiences of the first-in-man use of the Cold Ablation Robot-guided Laser Osteotome (CARLO®). Methods: The CARLO® device employs a stand-alone 2.94-µm erbium-doped yttrium aluminum garnet (Er:YAG) laser mounted on a robotic arm. A 19-year-old patient provided informed consent to undergo bimaxillary orthognathic surgery. A linear Le Fort I midface osteotomy was digitally planned and transferred to the CARLO® device. The linear part of the Le Fort I osteotomy was performed autonomously by the CARLO® device under direct visual control. All pre-, intra-, and postoperative technical difficulties and safety issues were documented. Accuracy was analyzed by superimposing pre- and postoperative computed tomography images. Results: The CARLO® device performed the linear osteotomy without any technical or safety issues. There was a maximum difference of 0.8 mm between the planned and performed osteotomies, with a root-mean-square error of 1.0 mm. The patient showed normal postoperative healing with no complications. Conclusion: The newly developed stand-alone CARLO® device could be a useful alternative to conventional burs, drills, and piezosurgery instruments for performing osteotomies. However, the technical workflow concerning the positioning and fixation of the target marker and the implementation of active depth control still need to be improved. Further research to assess safety and accuracy is also necessary, especially at osteotomy sites where direct visual control is not possible. Finally, cost-effectiveness analysis comparing the use of the CARLO® device with gold-standard surgery protocols will help to define the role of the CARLO® device in the surgical landscape.

13 August 2021 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
Neha SharmaNeha Sharma
Neha Sharma
DWDennis Welker
Dennis Welker
SASoheila Aghlmandi
Soheila Aghlmandi
MMMichaela Maintz
Michaela Maintz
HZHans-Florian Zeilhofer
Hans-Florian Zeilhofer
Florian Markus ThieringerFlorian Markus Thieringer
Florian Markus Thieringer
Pure orbital blowout fractures occur within the confines of the internal orbital wall. Restoration of orbital form and volume is paramount to prevent functional and esthetic impairment. The anatomical peculiarity of the orbit has encouraged surgeons to develop implants with customized features to restore its architecture. This has resulted in worldwide clinical demand for patient-specific implants (PSIs) designed to fit precisely in the patient’s unique anatomy. Material extrusion or Fused filament fabrication (FFF) three-dimensional (3D) printing technology has enabled the fabrication of implant-grade polymers such as Polyetheretherketone (PEEK), paving the way for a more sophisticated generation of biomaterials. This study evaluates the FFF 3D printed PEEK orbital mesh customized implants with a metric considering the relevant design, biomechanical, and morphological parameters. The performance of the implants is studied as a function of varying thicknesses and porous design constructs through a finite element (FE) based computational model and a decision matrix based statistical approach. The maximum stress values achieved in our results predict the high durability of the implants, and the maximum deformation values were under one-tenth of a millimeter (mm) domain in all the implant profile configurations. The circular patterned implant (0.9 mm) had the best performance score. The study demonstrates that compounding multi-design computational analysis with 3D printing can be beneficial for the optimal restoration of the orbital floor.

26 October 2020 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
BKBurkhard Kunzendorf
Burkhard Kunzendorf
MDMariana Cardoso Diogo
Mariana Cardoso Diogo
DCDelfina Covini
Delfina Covini
MWMichael Weber
Michael Weber
GGGerlinde Maria Gruber
Gerlinde Maria Gruber
DPDaniela Prayer
Daniela Prayer
Dental anomalies coincide with genetic disorders, and prenatal identification may contribute to a more accurate diagnosis. The aim of this study was to assess whether fetal Magnet Resonance Imaging (MRI) is suitable to visualize and investigate intrauterine dental development in the upper jaw, and to compare the quality of visibility of tooth buds between 1.5 Tesla (T) and 3T images. MR images of fetuses Gestational Week (GW) 26.71 ± 4.97 from 286 pregnant women with diagnoses unrelated to dental anomalies were assessed by three raters. We compared the visibility between groups and field strengths in five gestational age groups, using chi square and Fisher’s exact tests. All ten primary tooth buds were identifiable in 5.4% at GW 18–21, in 75.5% at GW 26–29, and in 90.6% at GW 34+. Before GW 30, more tooth buds were identifiable on 3T images than on 1.5T images. Statistical significance was only reached for identification of incisors (p = 0.047). Therefore, 1.5T and 3T images are viable to visualize tooth buds, particularly after GW 25, and their analysis may serve as diagnostic criterion. MRI tooth bud data might have an impact on various fields of research, such as the maldevelopment of teeth and their causes. Analyzing tooth buds as an additional diagnostic criterion is not time consuming, and could lead to an improvement of syndrome diagnosis.