Journal of Craniomandibular Function, 2/2024
SciencePages 117-132, Language: English, GermanKordaß, Bernd / Ruge, Sebastian / Imhoff, Bruno / Güth, Jan-Frederik / Reich, Sven / Schlenz, Maximiliane A. / Hugger, Sybille / Hugger, AlfonsPosition Paper of the Study Group for Oral Physiology and Masticatory Function (DGFDT)Rapid developments in digital dentistry, such as digital workflows and CAD/CAM systems, have led to questions about digital occlusion, including the capabilities of occlusal analysis. There is a need for clear definitions and terminology. What do we mean when we talk about “occlusion” in the context of digitization, especially in the case of digital models? What are the capabilities of digital occlusal analysis? The following article presents our initial thoughts on this important topic, which may be useful in the development of future guideline.
Keywords: digital occlusion, digital occlusion analysis, virtual articulator, digital articulator, digital patient, digital functionally generated path technique (FGP technique)
QZ - Quintessenz Zahntechnik, 10/2024
WissenschaftPages 938-947, Language: German, EnglishKordaß, Bernd / Ruge, Sebastian / Imhoff, Bruno / Güth, Jan-Frederik / Reich, Sven / Schlenz, Maximiliane A. / Hugger, Sybille / Hugger, Alfons
Rapid developments in digital dentistry, such as digital workflows and CAD/CAM systems, have led to questions about digital occlusion, including the capabilities of occlusal analysis. There ist a need for clear definitions and terminology. What do we mean when we talk about “occlusion” in the context of digitization, especially in the case of digital models? What are the capabilities of digital occlusal analysis? The following article presents our initial thoughts on this important topic, which may be useful in the development of future guideline.
Quintessenz Zahnmedizin, 5/2022
Zahnheilkunde interdisziplinärPages 508-513, Language: GermanKordaß, Bernd / Ruge, SebastianDie Digitalisierung in der Zahnmedizin und Zahntechnik schreitet unaufhaltsam voran. Auch die Funktionsdiagnostik und -therapie einschließlich der Kieferrelationsbestimmung profitiert davon. Allerdings ist es wichtig zu wissen, was der digitalen Okklusion zugrunde liegt und welche Gesichtspunkte bei der Interpretation zu berücksichtigen sind. Gegenüber der analogen Welt liegt alles in „Zahlen“ vor, was ohne Zweifel ein eminenter Vorteil ist. Vor allem lassen sich auch die Fehler und Unschärfen besser einschätzen, mit denen wir es beim Scannen und Registrieren, aber letztlich auch beim Umsetzen und Fertigen von Restaurationen zu tun haben. In der praktischen Anwendung kommt es trotz allem auf viel Erfahrungswissen und letztlich intuitives Ausprobieren an, bis wirklich ein zufriedenstellendes Optimum erreicht werden kann.
Manuskripteingang: 14.03.2022, Manuskriptannahme: 17.03.2022
Keywords: Digitale Okklusion, digitale Simulation, CAD/CAM, Okklusionsanalyse
Journal of Craniomandibular Function, 3/2022
SciencePages 193-204, Language: English, GermanRuge, Sebastian / Kordaß, BerndWhen utilizing CAD/CAM systems to design and manufacture dental prostheses and occlusal splints, one soon wonders: How accurate is virtual occlusion? Conventional methods involving dental impressions, plaster casts, articulators, and manual verification tools such as articulating paper have well-known sources of error and error chains, and tried and tested error-handling strategies for many of them already exist. Digital workflows, on the other hand, are still very new and unfamiliar to some dentists. Besides digital processes such as intraoral scanning and optoelectronic jaw motion tracking, analog processes may also be required. The penetration of maxillary and mandibular dental models is one aspect of digital dentistry that immediately attracts attention. Virtual penetration occurs because digital technology, like every measuring system, is subject to measurement error, and because virtual reality can only approximate the true variable nature of the physiologic masticatory system. The present article aims to identify and discuss variables that affect the accuracy of virtual occlusion. Some errors are first discovered in the digital world. Virtual capabilities open up new perspectives that have yet to be explored and understood.
Keywords: occlusion, virtual articulator, intraoral scan, jaw motion tracking
Journal of Craniomandibular Function, 2/2022
SciencePages 115-128, Language: English, GermanKordaß, Bernd / Amlang, Alexandra / Hugger, Alfons / Behrendt, Christoph / Ruge, SebastianEvaluations of the regional baseline study (SHIP-1) with the Greifswald Digital Analyzing System (GEDAS)Sufficient occlusion is a basic prerequisite for the functional efficiency of the occlusal surfaces. Exactly where and in what number the occlusal contacts in the posterior region should be present for this purpose is controversial.
Aim: The present study investigated the number and location of occlusal contacts on posterior teeth without dental findings, ie, without caries or restorative restorations such as fillings, crowns, etc. Such natural posterior teeth were present in 709 subjects (males [m] = 446: 48.9 ± 13.04 years, females [f] = 283: 52.4 ± 14.23 years) of a subject collective of 1223 subjects (m = 648, f = 575) of the regional baseline study ‘Study of Health in Pomerania 1’ (SHIP-1).
Materials and method: Silicone bite registrations in habitual intercuspation (IP) were evaluated, whereby the test persons were asked to fix the bite block with biting force without biting firmly. The registrations were scanned with a document scanner in incident and transmitted light; a calibration strip was used to determine the transparency threshold of a layer thickness of 20 μm, below and equal to which the transparent zone was considered as a contact or contact area. The Greifswald Digital Analyzing System 2 (GEDAS 2) software was used to determine the number and location of occlusal contact areas tooth by tooth. To define the localization of the contacts, a cross with two concentric circles symmetric to the longitudinal fissure was superimposed on the occlusal surface; this resulted in four inner and four outer quadrants. Thus, the number of pixels in occlusal contact areas per inner and outer quadrant could be determined. The image resolution was 300 dpi.
Results: On average (median), the premolars had two occlusal contacts each, the posterior teeth had four to five, and Vieltooth 46 had six contacts. The right and left teeth did not differ in the frequency of occlusal contacts in the Mann-Whitney U test for independent samples. In the maxillary premolars, frequent contact areas were primarily located mesially on the inner and outer slopes of the palatal cusp. In the maxillary molars, the palatal slope of the distopalatal cusp and the inner slopes of the mesiopalatal and distopalatal cusps were frequently addressed. On the mandibular premolars, the inner slopes of the buccal cusps and the buccal slope of the distobuccal cusp were particularly frequently addressed; in teeth 35 and 45, the buccal slope of the mesiobuccal cusp was also somewhat more frequently addressed. Teeth 36 and 46 frequently had contact areas on the buccal slope of the distobuccal cusp as well as on the inner slopes of the distal cusps (distobuccal and distolingual), whereas teeth 37 and 47 tended to behave similarly.
Conclusion: Epidemiologically, the focus of the frequent contact areas on the respective supporting cusps of the maxillary and mandibular posterior teeth and a distribution of contacts stabilizing the tooth in its position in the dental arch through the interlocking were confirmed. It makes sense to take this into account when designing occlusal surfaces in the posterior region.
Keywords: occlusion, occlusal contacts, posterior teeth, epidemiology
International Journal of Computerized Dentistry, 1/2022
SciencePubMed ID (PMID): 35322652Pages 47-56, Language: English, GermanKordaß, Bernd / Amlang, Alexandra / Hugger, Alfons / Behrendt, Christoph / Ruge, SebastianSufficient occlusion is a basic prerequisite for the functional efficiency of the occlusal surfaces. Exactly where and in what number the occlusal contacts in the posterior region should be present for this purpose is controversial. The present study investigated the number and location of occlusal contacts on posterior teeth without dental findings, ie, without caries or restorative restorations such as fillings, crowns, etc. Such natural posterior teeth were present in 709 subjects (males (m) = 446: 48.9 ± 13.04 years, females (f) = 283: 52.4 ± 14.23 years) of a subject collective of 1223 subjects (m = 648, f = 575) of the regional baseline study ‘Study of Health in Pomerania 1’ (SHIP-1).
Silicone bite registrations in habitual intercuspation (IP) were evaluated, whereby the test persons were asked to fix the bite block with biting force without biting firmly. The registrations were scanned with a document scanner in incident and transmitted light; a calibration strip was used to determine the transparency threshold of a layer thickness of 20 μm, below and equal to which the transparent zone was considered as a contact or contact area. The Greifswald Digital Analyzing System 2 (GEDAS 2) software was used to determine the number and location of occlusal contact areas tooth by tooth. To define the localization of the contacts, a cross with two concentric circles symmetric to the longitudinal fissure was superimposed on the occlusal surface; this resulted in four inner and four outer quadrants. Thus, the number of pixels in occlusal contact areas per inner and outer quadrant could be determined. The image resolution was 300 dpi.
On average (median), the premolars had two occlusal contacts each, the posterior teeth had four to five, and tooth 46 had six contacts. The right and left teeth did not differ in the frequency of occlusal contacts in the Mann-Whitney U test for independent samples. In the maxillary premolars, frequent contact areas were primarily located mesially on the inner and outer slopes of the palatal cusp. In the maxillary molars, the palatal slope of the distopalatal cusp and the inner slopes of the mesiopalatal and distopalatal cusps were frequently affected. On the mandibular premolars, the inner slopes of the buccal cusps and the buccal slope of the distobuccal cusp were particularly frequently addressed; in teeth 35 and 45, the buccal slope of the mesiobuccal cusp was also somewhat more frequently addressed. Teeth 36 and 46 frequently had contact areas on the buccal slope of the distobuccal cusp as well as on the inner slopes of the distal cusps (distobuccal and distolingual), whereas teeth 37 and 47 tended to behave similarly.
Epidemiologically, the focus of the frequent contact areas on the respective supporting cusps of the maxillary and mandibular posterior teeth and a distribution of contacts stabilizing the tooth in its position in the dental arch through the interlocking were confirmed. It makes sense to take this into account when designing occlusal surfaces in the posterior region.
Keywords: occlusion, occlusal contacts, posterior teeth, epidemiology
International Journal of Computerized Dentistry, 3/2021
SciencePubMed ID (PMID): 34553892Pages 275-282, Language: English, GermanCordeiro, Nithin / Splieth, Christian H. / Ruge, Sebastian / Kordaß, Bernd / Vielhauer, Annina / Krey, Karl-Friedrich / Santamaría, Ruth MAim: The present prospective clinical study aimed to validate the Greifswald Digital Analyzing System (GEDAS) as a method for digital assessment of the occlusion in primary and mixed dentition.
Materials and methods: The reproducibility of GEDAS in primary and mixed dentition was assessed using the intraclass correlation coefficient (ICC). In addition, the acceptability of the method to the dentist, the child, and the parent/caregiver was assessed using a modified visual analog scale of faces, the Frankl behavior scale, and the 10-point Likert scale. In total, 20 participants aged between 3 and 9 years (mean age: 6; standard deviation: ± 1.74) with primary (n = 10) and mixed (n = 10) dentition were recruited.
Results: The ICC for the number of contact points in all teeth was 0.94 and for the area of contact points was 0.97, indicating good to excellent reproducibility. The average total number of contacts per bite registration per arch in the primary and mixed dentition was 36.5 (17 to 66) and 37.9 (9 to 74), respectively. The average of the total area of interocclusal contact area in the primary and mixed dentition was 25.55 mm2 (5.39 to 70.20) and 29.59 mm2 (2.80 to 78.53), respectively. During the procedure, the majority of dentists reported the child’s behavior to be positive (85%) and found the procedure easy to perform (80%), short (6.0 min), and tolerable (80%).
Conclusion: GEDAS is an occlusal analysis tool with good acceptability and reproducibility in children and could be considered for the planning and assessment of restorative and orthodontic treatment in the intermediate stages.
Keywords: GEDAS, occlusion, digital, primary dentition, mixed dentition, bite registration
QZ - Quintessenz Zahntechnik, 9/2020
ExpertenfokusPages 1016-1020, Language: GermanRuge, Sebastian / Kordaß, BerndBei der Digitalisierung beispielsweise von Modellen kommt es schnell zu Durchdringungen, die es in der Realität nicht gibt. Allerdings treten Abweichungen auch bei analogen Modellen auf. In jedem Fall ist es sinnvoll, die Okklusion durch ein zweites Verfahren zu überprüfen. Für digitale Restaurationen kann es sinnvoll sein, auch einmal leichte Durchdringungen zuzulassen, weil eventuell auch bewusst Führungsstrukturen aufgebaut werden sollen, die zunächst in der Konstruktion Durchdringungen zeigen. Die Erfahrung und Kompentenz der Zahntechniker kann bei der Weiterentwicklung der Systeme hilfreich sein.
Keywords: digitales Modell, Durchdringung, Intraoralscan, Okklusion
QZ - Quintessenz Zahntechnik, 8/2020
KurzfassungPages 910-911, Language: GermanKordaß, Bernd / Bernhardt, Olaf / Ruge, Sebastian / Ratzmann, Anja / Hugger, Sybille / Hugger, AlfonsAuswertungen des assoziierten Projekts zur SHIP-StudieInternational Journal of Computerized Dentistry, 4/2020
ApplicationPubMed ID (PMID): 33491932Pages 363-375, Language: English, GermanKordaß, Bernd / Behrendt, Christoph / Ruge, SebastianA hands-on method for instrument-based occlusal analysis with digital technology is presented using a patient case example. The method is based on new software for digital occlusal analysis that includes a new measuring system for recording mandibular function (Jaw Motion Analyser Optic System/oJMA). With the new system, occlusal contact patterns in the real movement function of the mandible are captured and analyzed digitally with regard to occlusal interferences or a suitable therapeutic position of the mandible. For this purpose, scans of both jaws are brought together with the movement recordings by means of a special coupling tray and then visualized together as one complete image. Since the movement paths of the temporomandibular joints (TMJs) are also captured, the new system makes it possible to define a suitable therapeutic position specifically aimed at relieving the TMJs, and a therapeutic change in the jaw relation can be adjusted, for instance, by using an occlusal splint. Dedicated software modules provide a layer-by-layer analysis of the intercuspation relationship and the generation of ‘envelopes’ for occlusal gliding movements. This system is used to gain a deeper and more comprehensive understanding of the relationship between the structure and function of the occlusion. Interfaces to CAD software have also been established.
Keywords: instrumental analysis of occlusion, digital occlusion, CAD/CAM