PlaneSystem® by MDT Udo Plaster, developed in cooperation with Zirkonzahn
- Novel approach for capturing of patient-specific information like the Natural Head Position (NHP) and ala-tragus plane for the exact determination of the occlusal plane, any associated natural asymmetries and the aesthetical position of the patient.
- No imprecise transfers thanks to face- or transfer bow
- 100 % integrated in the digital Workflow, 1:1 transfer of the exact position into the virtual articulator of the modelling software Zirkonzahn.Modellier
- Ideally combinable with patient photos and face scan data (Face Hunter)
- Optimized definition of the centric position and jaw relationship, thanks to a correctly positioned upper jaw
- Zebris system compatible, suitable for splint therapy (in course of preparation)
- Increased planning security for dentists, dental technicians and patients
- Ideally suited for patient counselling
Rough Workflow overview
1. In the dental practice
- Capturing of the face physiognomy of the patient with the Face Hunter facial scanner (optional) or by taking conventional patient photos
- Capturing of the patient-specific planes (ala-tragus plane and natural head position) by the dentist using the Plane Finder
2. In the dental practice or in the laboratory
- Model analysis, determining of the masticatory centre and centre line etc.
- Fixation of the upper jaw model in the Plane Positioner using an exact reproduction of the NHP as well as of the identified angle to the ala-tragus line
- Fixation of the PlanePositioner® with upper jaw model in the PS1 physical articulator
3. In the laboratory
- Scanning of the articulated models with the scanner S600 ARTI
- Transfer to the PS1 virtual articulator in the modelling software Zirkonzahn.Modellier
- Import and matching of the situation with the Face Hunter facial scans or portrait photos
- Virtual modelling of the restoration in the modelling software Zirkonzahn.Modellier
The third dimension in patient analysis
In clinical practice, incorrectly inclined occlusal planes and functionally inadequate restorations are a common scourge. A possible reason is the often imprecise analysis of patient information. Now Udo Plaster, master dental technician from Nürnberg, has developed a novel transfer approach, the PlaneSystem®.
It determines the occlusal plane and any associated asymmetries individually for each patient based on the ala-tragus plane and natural head position (NHP) and transmits the real position to the CAD/CAM system.
For an uninterrupted digital workflow, the data received and the corresponding coordinates in three-dimensional space must be correctly matched. This can be done with the S600 ARTI structured-light optical scanner and the virtual articulator implemented in the Zirkonzahn modelling software. The scanner acquires the data of the models from the PS1 articulator and transfers them directly to the software’s virtual articulator.
This allows possible compensations to be detected prior to developing a treatment plan for laboratory or chairside restorations, minimising or completely eliminating any sources of error, particularly during data transfer, which might otherwise occur when planning or fabricating a dental restoration.
The next step is the actual modelling of the restoration in the modelling software Zirkonzahn.Modellier. Ideally, the physiognomy of the patient is taken into account during this step. This is now made possible by the Face Hunter 3D facial scanner.
The almost photo-realistic digital face data of the patient can be used either as validity or reference values, but are also ideal for the planning and consultation process between dentist and patient.
Scientific background to the Plaster transfer approach
Scientific studies, e.g. by Xie and coworkers, have identified the connecting line from the lower edge of the nasal wing to the centre of the tragus, the so-called ala-tragus line, to be a more reliable reference for the occlusion line than Camper’s plane or the Frankfurt horizontal plane. The deviation of the ala-tragus plane from the occlusal line is minimal. The ala-tragus line varies from patient to patient, with hemifacial asymmetries a not infrequent occurrence. In order to reliably reproduce the occlusal plane, it is necessary to determine it independently of skeletal class.
The Natural Head Position (NHP)
The second important point of reference within Plaster’s method of transfer is the natural head posture (NHP). A 5-year study by Cooke (2) has shown that patients’ natural head posture varies by only one to two degrees when looking directly into his or her own eyes as they stand upright in front of a mirror. This result is supported by a 15-year study by Peng et al.
The NHP is related to a patient-independent reference frame that allows patient-specific variations in spatial orientation to be reproduced.
Topic-related Studies and Specialist articles
Plaster U. Natürliche Asymmetrien und die patientenindividuelle Wiedergabe der Okklusionsebene ohne traditionellen Transferbogen.
Quintessenz Zahntech 2013;39(5): 1266-1280
Xie J, Zhao Y, Chao Y, Luo W. A cephalometric study on determining the orientation of occlusal plane.
Hua Xi Yi Ke Da Xue Xue Bao. 1993 Dec;24(4): 422-5
Sinobad D, Postic SD. Roentgencraniometric indicators of the position of the occlusal plane in natural and artificial dentitions.
Eur J Prosthodont Restor Dent. 1996 Dec;4(4): 169-74
Cooke MS. Five-year reproducibility of natural head posture:A longitudinal study.
Am J Orthod Dentofacial Orthop 1990; 97: 487-94
Peng, L. Cooke, MS.: Fifteen-year reproducibility of natural head posture: A longitudinal study.
Am J Orthod Dentofacial Orthop 116 (1) 1999: 82-85