EditorialPubMed ID (PMID): 34006058Pages 3-4, Language: English, GermanBeuer, Florian
SciencePubMed ID (PMID): 34006059Pages 9-17, Language: English, GermanDuré, Michael / Berlinghoff, Frank / Kollmuss, Maximilian / Hickel, Reinhard / Huth, Karin Christine
Aim: The transfer of 3D implant position planning to the clinical site is challenging. The aim of this study was to compare in vitro this transfer accuracy by using dynamic real-time navigation or static surgical guides.
Materials and methods: Deviations between planned and actual pilot drill positions were calculated (Denacam and NobelGuide; each n = 90), matching pre- and postoperative CBCT images: entry point, angle, tip (each 3D); depth, mesiodistal/bucco-oral entry points, and angles (each 1D). The influence of the maxilla and mandible, implant region (anterior/posterior), and marker position (ipsilateral/contralateral, Denacam only) was investigated (Mann-Whitney U test).
Results: No significant differences occurred regarding entry point (3D), mesiodistal/bucco-oral entry points (1D) or mesiodistal angle (1D) (P > 0.05). The angular and tip deviations (3D) were significantly smaller using Denacam (2.16 ± 0.59 degrees, 0.80 ± 0.55 mm; NobelGuide 2.54 ± 1.19 degrees, 1.09 ± 0.56 mm; P = 0.024, P < 0.0001). The deviations in depth and bucco-oral angle (1D) were significantly smaller using NobelGuide (1.05 ± 0.50 mm, 1.02 ± 1.16 degrees; Denacam 1.50 ± 0.64 mm, 1.51 ± 0.82 degrees; P < 0.0001). Significantly smaller deviations occurred within the mandible (Denacam, 5/8 parameters). Region and marker position showed no influence. No distinct influences were found with the use of NobelGuide.
Conclusion: Denacam might possibly be a promising alternative to static surgical guides.
Keywords: dynamic navigation, dental implantology, surgical guide, implant planning
SciencePubMed ID (PMID): 34006060Pages 19-27, Language: English, GermanCho, Jin-yong / Kim, Sung-beom / Ryu, Jaeyoung
Aim: To conduct an observational study evaluating the efficacy of a partially guided system for implant surgery.
Materials and methods: The study included 48 implant placements in 24 patients. Following virtual implant planning with designated software, a surgical guide was fabricated using a 3D desktop printer. Each surgically placed implant was compared with its planned position in the software. The coronal and apical distance and angular errors of the implants were evaluated. The correlation between the errors and the variables (residual bone height, surgeon, implant placement site, guide support type, implant diameter) was analyzed using multiple regression analysis.
Results: The coronal and apical mean distance errors were 1.28 ± 0.85 and 1.8 ± 0.97 mm, respectively. The mean angular error was 3.66 ± 3.37 degrees. The correlation coefficients (coronal: 0.285; apical: 0.308) indicated a significant linear correlation between the anterior and posterior implant placement positions (P < 0.05).
Conclusion: A partially guided system with in-office guide fabrication using a 3D desktop printer is a useful option for implant placement.
Keywords: computer-guided surgery, dental implants, printing, three-dimensional, surgical guide
SciencePubMed ID (PMID): 34006061Pages 29-40, Language: English, GermanSon, Keunbada / Lee, Kyu-Bok
Ziel: Ziel dieser Studie war es, die Genauigkeit von Intraoralscans eines Zahnmodells für vier verschiedene Situationen bezüglich der Präparationsgrenze (supragingival, epigingival, subgingival, subgingival mit Retraktionsfaden) zu vergleichen.
Material und Methode: Um klinische Bedingungen zu simulieren, wurden die Pfeilerzahnmodelle aus Keramik gefertigt. Zur Herstellung von transluzenter künstlicher Gingiva wurde ein transparentes kieferorthopädisches Silikon mit einem Farbstoff versetzt. Mithilfe eines Kontaktscanners wurde ein CAD-Referenzmodell gewonnen. Die Präparationsgrenzen der Pfeilerzahnpräparation wurden subgingival (0,5 mm apikal des Gingivarands), epigingival oder supragingival (0,5 mm koronal des Gingivarands) angelegt. Zusätzlich wurde unterhalb der subgingivalen Präparationsgrenze ein Retraktionsfaden im Sulkus platziert. Zwei Intraoralscanner (i500, Fa. Medit, bzw. EZIS PO, Fa. DDS, n = 20 pro Präparationsgrenzentyp) kamen zum Einsatz, um die CAD-Testmodelle zu generieren. Die Testmodelle wurden in einer 3-D-Analysesoftware mit dem Referenzmodell überlagert und analysiert. In der statistischen Auswertung wurde mittels einfaktorieller Varianzanalyse die Genauigkeiten für die vier Präparationsgrenzen-Situationen verglichen (α = 0,05). Für die Unterschiede zwischen den Gruppen erfolgte zudem eine Post-hoc-Analyse mit dem Tukey-HSD-Test.
Ergebnisse: Bezüglich der Genauigkeit der Intraoralscans fanden sich signifikante Unterschiede zwischen den Präparationsgrenzenniveaus (p < 0,001). Bei epi- und subgingivalen Präparationsgrenzen war die Genauigkeit gering. Der Einsatz von Retraktionsfäden verbesserte die Genauigkeit signifikant (p < 0,05). Zudem fanden sich signifikante Unterschiede zwischen den Intraoralscannern, von denen der i500 eine höhere Genauigkeit erreichte als der EZIS PO (p < 0,001).
Schlussfolgerung: Für klinisch ausreichend genaue (< 100 µm) Intraoralscans von Präparationsrändern ist eine supragingivale Lage der Präparationsgrenzen oder der Einsatz von Retraktionsfäden zu empfehlen.
Keywords: Präparationsgrenze, Präparation, Intraoralscanner, Genauigkeit
SciencePubMed ID (PMID): 34006062Pages 41-51, Language: English, GermanEid, Rita / Tribst, João Paulo Mendes / Juloski, Jelena / Özcan, Mutlu / Salameh, Ziad
Aim: To evaluate the fracture resistance and failure pattern of endodontically treated teeth with post and cores made of different CAD/CAM materials in comparison with cast post and cores.Materials and methods: A total of 40 maxillary central incisors were divided into four groups. Post and cores were fabricated using the following materials: fiber-reinforced composite, high-density polymer, polymer-infiltrated ceramic network, and nonprecious metal alloy as a control group. Specimens were covered with lithium disilicate crowns and subjected to thermomechanical cyclic loading followed by fracture resistance testing until failure. One-way ANOVA followed by Bonferroni multiple comparison tests were used to determine significant differences between the four groups. The significance level was set at 0.05. 3D finite element analysis was then performed, and results were analyzed based on the von Mises stress distribution criteria and the maximum principal stress for the possible failure areas.Results: No statistically significant differences were found in the fracture resistance between the four groups. In terms of unrestorable failures, no significant differences were found among the tested groups.Conclusion: The tested post and cores have comparable fracture resistance to that of metallic cast post and cores in the anterior region.Clinical significance: Post and cores made of CAD/CAM materials offer an acceptable alternative for the restoration of anterior teeth.
Keywords: post and cores, fracture resistance, hybrid ceramics, fiber-reinforced composite, finite element analysis
SciencePubMed ID (PMID): 34006063Pages 53-63, Language: English, GermanLo Giudice, Antonino / Ronsivalle, Vincenzo / Pedullà, Eugenio / Rugeri, Michele / Leonardi, Rosalia
Ziel: Zur Passung von 3-D-gedruckten Okklusionsschienen sind nur wenige Daten verfügbar. Ziel der vorliegenden Studie war es, die Passung von 3-D-gedruckten Schienen zu untersuchen, die mit verschiedenen Offset-Werten digital konstruiert und in zwei unterschiedlichen biokompatiblen Kunststoffen gedruckt worden waren.
Material und Methode: Für zehn inkludierte digitale Modelle wurden Okklusionsschienen mit verschiedenen Offset-Werten (0,0, 0,05, 0,10, 0,15, 0,20 und 0,25 mm) konstruiert. Jede Schiene wurde in zwei biokompatiblen Kunststoffen 3-D-gedruckt. Der Spalt zwischen der Schiene und den Zähnen wurde mithilfe von Abformmaterial registriert. Mit spezieller 3-D-Technik wurde das Spaltvolumen zwischen der Schiene und den Zähnen bestimmt und der euklidische Abstand zwischen den Oberflächenpunkten des jeweiligen digitalen Modelles mit und ohne Spaltvolumen berechnet.
Ergebnisse: Die Schienen mit einem Offset-Wert von 0,20 mm zeigten ein kleineres Spaltvolumen und geringere Werte bei der Abweichungsanalyse als diejenigen mit Offset-Werten von 0,15 und 0,25 mm (p < 0,05). Diese Ergebnisse galten für beide verwendeten biokompatiblen Kunststoffe. Für keinen der getesteten Offset-Werte fanden sich beim Spaltvolumen und den Werten der Abweichungsanalyse der jeweiligen Schiene signifikante Differenzen zwischen den beiden Kunststoffen.
Schlussfolgerung: Ausgehend von den Befunden dieser Studie ist bei der digitalen Konstruktion von Okklusionsschienen ein Offset-Wert von 0,20 mm die beste Wahl.
Keywords: 3-D-Druck, CAD/CAM, Schiene, Aufbissbehelf, Okklusionsschiene, digitale Zahnmedizin, digitale Kieferortopädie
ApplicationPubMed ID (PMID): 34006064Pages 65-76, Language: English, GermanBartella, Alexander K / Kamal, Mohammad / Kuhnt, Thomas / Hering, Kathrin / Halama, Dirk / Pausch, Niels C. / Lethaus, Bernd
Introduction: Mixed reality (MR) represents a new evolution in technological development that combines both virtual reality (VR) and augmented reality (AR) to create a blend of the physical and digital worlds. However, the potential role of MR in preoperative diagnostics in oral and maxillofacial surgery has not been scientifically investigated and remains generally unclear. This article presents a workflow that integrated MR in its scheme. It also evaluates the potential benefit of MR compared with its predecessors, VR and AR.Material and methods: MR technology was used to plan the surgical treatment of a clinical case with an extensive tumor of the left maxilla. A workflow proposal incorporating both the surgeon and radiation oncologist is presented based on this experience. A total of 10 examiners rated the usability and applicability of MR for daily routines.Results: MR showed good results during preoperative planning for a surgically extensive case in terms of displaying 3D structures and enhancing the physical and virtual interactions among the examiners. Previously described drawbacks of other VR/AR applications such as nausea and motion sickness were not observed with MR. However, MR seems to lack intraoperative usability, which is a drawback.Conclusion: MR shows great potential in improving the preoperative assessment of 3D DICOM datasets and thus facilitating diagnostic measures. However, further improvements should be made to implement an MR workflow and incorporate it into the clinical treatment planning tree.
Keywords: mixed reality, virtual reality, augmented reality, preoperative planning
ApplicationPubMed ID (PMID): 34006065Pages 77-88, Language: English, GermanElsayed, Adham
For restoring extensive cavities in severely damaged or decayed posterior teeth, especially those with thin walls, indirect restorations are recommended rather than direct fillings. Regarding indirect restorations for inlays and onlays, composite resin-based CAD/CAM materials are considered to have several advantages over ceramics such as easy manufacturing, lower cost, and simpler repairability. A case is presented in this article in which the treatment plan and protocol combine multiple evidence-based clinical techniques such as immediate dentin sealing (IDS), cavity design optimization (CDO), and cervical margin relocation (CMR). For CDO and CMR, two different types of flowable composite resins with different viscosities were used. Restoring such extensively damaged teeth using a defect-oriented adhesive technique is considered a challenge both in terms of the preservation of healthy tooth structure and the proper isolation for adhesive luting. The IDS technique was used to enhance the bonding to the remaining dentin, while CDO was performed to avoid unnecessary removal of vital tooth structure, for example, undercuts. The deep subgingival margins were elevated using the CMR technique to facilitate the impression taking and a contamination-free luting of the final restoration. Combining the aforementioned techniques enabled a defect-oriented, minimally invasive restoration of a severely decayed tooth. The aim of this article is to present those techniques in a simplified way through a clinical case as a step-by-step guide for the practitioner.
Keywords: onlay, minimally invasive, immediate dentin sealing, cavity design optimization, cervical margin relocation, flowable composite, CAD/CAM, composite blocks
ApplicationPubMed ID (PMID): 34006066Pages 89-101, Language: English, GermanAl-Haj Husain, Nadin / Molinero-Mourelle, Pedro / Janner, Simone F. M. / Brägger, Urs / Özcan, Mutlu / Schimmel, Martin / Revilla-Léon, Marta / Abou-Ayash, Samir
Ziel: Dieser Fallbericht beschreibt einen digitalen Workflow für die prothetisch orientierte Behandlungsplanung, Implantatinsertion und Herstellung zweier verschraubter, implantatgetragener Full-arch-Brücken bei einem zahnlosen Patienten. Ziel der Kasuistik ist es, die digitalen Arbeitsschritte des Workflows, insbesondere die Scantechnik für die Erfassung der zentrischen Kondylenposition, anhand eines klinischen Falls zu zeigen und zu erläutern. Außerdem werden die Grenzen des Workflows diskutiert.Material und Methoden: Die statische computergestützte Implantation (static Computer-aided Implant Surgery, s-CAIS) wurde auf Basis einer digitalen Volumentomografie, eines Intraoralscans und eines digitalen Bissregistrats dreidimensional geplant. Mittels s-CAIS wurden vier Implantate im Unter- und sechs Implantate im Oberkiefer des unbezahnten Patienten platziert. Die definitiven Full-arch-Restaurationen aus monolithischem Zirkonoxid wurden in einem digitalen Workflow hergestellt, der die zuvor benutzte Röntgenschablone in modifizierter Form für die digitale Kieferrelationsbestimmung nutzte.Schlussfolgerungen: Die Entwicklung digitaler Methoden ermöglicht die Konstruktion, Verarbeitung und Herstellung implantatgetragener Full-arch-Versorgungen in einem chirurgischen, prothetischen und zahntechnischen Workflow auf Grundlage eines dreidimensionalen Backward-Planning. Anhand der digitalen prothetischen Aufstellung lassen sich mittels CAD/CAM-Technik intraorale Prototypen herstellen, die als Vorlage für die definitive monolithische Zirkonoxid-Suprastruktur dienen.
Keywords: Backward Planning, unbezahnt, implantatgetragen, Full-arch-Brücke, Oberkiefer, Unterkiefer, CAD/CAM, monolithisch, Zirkonoxid, Röntgenschablone
Online OnlyScienceDOI: 10.3290/j.ijcd.b994539, PubMed ID (PMID): 33634681Pages 1-9, Language: EnglishCaliskan, Secil / Tuloglu, Nuray / Celik, Ozer / Ozdemir, Canan / Kizilaslan, Sena / Bayrak, Sule
Aim: The aim of the study was to compare the success and reliability of an artificial intelligence (AI) application in the detection and classification of submerged teeth in panoramic radiographs.
Materials and methods: Convolutional neural network (CNN) algorithms were used to detect and classify submerged molars. The detection module, based on the stateof- the-art Faster R-CNN architecture, processed a radiograph to define the boundaries of submerged molars. A separate testing set was used to evaluate the diagnostic performance of the system and compare it with that of experts in the field.
Result: The success rate of the classification and identification of the system was high when evaluated according to the reference standard. The system was extremely accurate in its performance in comparison with observers.
Conclusions: The performance of the proposed computeraided diagnosis solution is comparable to that of experts. It is useful to diagnose submerged molars with an AI application to prevent errors. In addition, this will facilitate the diagnoses of pediatric dentists.
Keywords: artificial intelligence, deep learning, infraocclusion, panoramic images, submerged teeth