EditorialPubMed ID (PMID): 35851353Pages 119-120, Language: English, GermanBeuer, Florian
ScienceDOI: 10.3290/j.ijcd.b2588185, PubMed ID (PMID): 35060372Pages 125-132, Language: English, GermanTatis, Diego Fernando / Medina, Claudia Ximena / Delgado, Diego / Agudelo, Fahuslly Issa / Wallis, Luis Samuel / García, Kevin Chica / Osorio, Adrián Fernández
Aim: Increased vertical growth of the maxilla is a condition that affects a large part of the population. The condition reveals a skeletal alteration of the cranio-masticatory system. One of the effects generated by the excessive vertical growth of the maxilla is a gingival smile pattern that can affect esthetic patterns as well as alter the masticatory biomechanics, which is a primary etiologic factor in temporomandibular dysfunction (TMD). Contemporary imaging aids help to optimize diagnostic analysis; perform treatment; and make an evaluation before, during, and after treatment. The present study aims to compare the clinical diagnosis of gingival smile with the dimensions of the dentoalveolar square, digitally calculated in the panoramic projection of the CBCT.
Materials and methods: In a sample of 37 patients, an analysis was performed of the correlation between the dimensions of the dentoalveolar square of the Tatis panoramic cephalometry and the clinical photometry, applying the Tjan gingival smile analysis.
Results: The results show that there is high correlation and agreement between the cephalometric measurement method of the dentoalveolar square and Tjan’s photometric measurement method. Both methods can be used to classify the smile type as high, medium or low.
Conclusions: Analysis of the dentoalveolar square of the panoramic cephalometry provides an accurate diagnosis of the anterior vertical dimension of the maxilla as it relates to the clinical diagnosis of smile.
Keywords: gingival smile, panoramic radiography, maxillary height, smile analysis, maxillary vertical dimension
ScienceDOI: 10.3290/j.ijcd.b2585503, PubMed ID (PMID): 35060368Pages 133-139, Language: English, GermanPetrie, Cynthia S. / Hayes, Katherine / Scott, JoAnna M. / Walker, Mary P.
Aim: The purpose of the present study was to investigate the effectiveness of digital impressions made by 3rd and 4th year dental students using a retrospective record review at one USA dental school during a 1-year period.
Materials and methods: After reviewing patient records related to quality assurance, 125 digital impressions and the produced restorations were evaluated. Effectiveness and acceptability of digital impressions and restorations were associated with students’ educational level, number of prepared teeth scanned, type of produced restoration, and restorative material used. Fisher’s exact and chi-square tests were used for the statistical analysis. All dental students had previous experience of the digital curriculum in their preclinical education.
Results: A total of 91% of the digital impressions were acceptable, and 80% of the produced restorations had clinically acceptable margins. Impression approval and restoration acceptance were not affected by students’ educational level, number of preparations or restoration type. Restoration acceptance was significantly affected by restorative material (P = 0.039), with higher rates of acceptable marginal integrity found with glass-ceramic and zirconia materials.
Conclusions: Within the parameters of the present study, 3rd and 4th year dental students, after having extensive education in the preclinical curriculum, can utilize digital impressions effectively for clinical practice. The results show that with adequate educational experiences, dental students can use digital impressions effectively for clinically acceptable restorations. Dental schools can and should educate students in digital dentistry.
Keywords: digital dentistry, digital imagining, digital impressions, CAD/CAM, intraoral scanners
ScienceDOI: 10.3290/j.ijcd.b2588203, PubMed ID (PMID): 35060373Pages 141-150, Language: English, GermanQin, Wenlong / Cong, Ming / Liu, Dong / Ren, Xiang
Aim: The full-contact model has been widely used in tooth preparation and prosthesis fabrication. However, it is rarely used in denture tests. The purpose of the present study was to design a suitable full-contact dental model for denture tests.
Materials and methods: A standard dental model with the complete tooth morphology was raster scanned and 3D reconstructed. Then, the positioning and fixing surfaces of the dental model were reshaped. The dental model was digitally trimmed into two parts: a fundamental part and a replaceable part. The modular design was presented according to dentition defects around the first molar. The prepared tooth replicas were designed through preparation/scanning/registration/separation sequences. The dental model was fabricated by stereolithography (SLA) 3D-printing rapid prototype technology. The static fracture force of the dental model was predicted using the finite element method. The effects of the four design methods on the suitability of the five testing operations (abutment fabrication, prosthesis fabrication, assembling, loading, and observation) were quantitatively analyzed. The static tests of three fixed partial dentures (FPDs), including tooth-supported, implant-supported, and tooth–tooth-supported prostheses, were conducted to investigate the fracture feature. The dynamic test of a removable partial denture (RPD) was undertaken to study the wear characteristic.
Results: The dental model could bear the maximum fracture strength of 4268.3 N. Seven positive and two negative effects of the design methods were produced. The maximum fracture strength of the FPDs were 1331.2 N, 1356.7 N, and 1987.7 N. The wear facets of the RPD in the dynamic denture test were distributed in three regions.
Conclusions: The force capacity of the full-contact dental model allows the application of static denture tests. The dental model provides improvements in fixture design, removable design, and replica design for the testing operations. The dental model is recommended more in the dynamic test than in the static test.
Keywords: dental model, denture test, computer-assisted design, 3D printing, computer-assisted analysis
ScienceDOI: 10.3290/j.ijcd.b2588131, PubMed ID (PMID): 35060369Pages 151-159, Language: English, GermanSchubert, Oliver / Edelhoff, Daniel / Erdelt, Kurt-Jürgen / Nold, Ephraim / Güth, Jan-Frederik
Aim: Milling-based, subtractive fabrication of digital complete dentures represents the computer-engineered manufacturing method of choice. However, efficient additive manufacturing technologies might also prove beneficial for the indication. The aim of the present study was to evaluate the accuracy of surface adaptation of complete denture bases fabricated using subtractive, additive, and conventional manufacturing techniques.
Materials and methods: A standardized edentulous maxillary model was digitally designed and milled. Twelve duplicated plaster casts were scanned and virtual denture bases designed accordingly. Physical complete denture bases (n = 12 per technique) were manufactured applying different digital and conventional fabrication methods: 1) CNC milling (MIL); 2) material jetting (MJ); 3) selective laser sintering (SLS); 4) digital light processing (DLP); and 5) conventional injection molding (INJ). The INJ group served as control. The intaglio surfaces of the denture bases were digitized and superposed with the surface data of the casts using a best-fit algorithm. Accuracy of surface adaptation was assessed by examining deviations. Statistical analysis was conducted using SPSS (P < 0.05).
Results: The milling of denture bases led to significantly better surface adaptation compared with all the other technologies (P < 0.001). The other fabrication methods in the study, including conventional manufacturing, revealed no considerable overall differences.
Conclusions: As regards the accuracy of surface adaptation, all the investigated technologies adequately produced complete denture bases, with milled denture bases presenting the most superior results.
Keywords: 3D printing, additive manufacturing, CAD/CAM, digital complete denture, digital light processing, denture fit, material jetting, milling, PolyJet technology, selective laser sintering
SciencePubMed ID (PMID): 35851354Pages 161-172, Language: English, GermanHerstell, Hannah / Berndt, Saskia / Kühne, Christina / Reich, Sven
Aim: To test four different measurement methods to evaluate deviations between planned and actual implant positions within a digital workflow applying 3D-printed surgical guides.
Materials and methods: A fully digital workflow was applied to simulate the single implant insertion to replace a maxillary missing central incisor and first molar in 10 gypsum casts (n = 10). Surgical guides (n = 10 per site) were printed by digital light processing for implant bed preparation and implant insertion. Four methods were used to analyze 3D deviations between the planned (target) and achieved implant positions: Methods 1 and 2 used an automated computer program (ACP) to assess deviations between the initial planning file and a file that represented the actual implant position either by the implant bed [ACP_BED] or by the inserted implant [ACP_IMP]. For Method 3, a standard tessellation language dataset representing the actual implant position was used and equipped with reference planes. This dataset was registered with the target planning, allowing manual measurements [MAN_MEAS]. Method 4 used a reverse engineering approach based on 3D high-resolution scans [REVERSE].
Results: Mean 3D deviations, including for anterior and posterior implant sites, ranged between 0.26 ± 0.11 mm [REVERSE] and 0.40 ± 0.09 mm [ACP_BED] at the implant shoulder, between 0.52 ± 0.24 mm [REVERSE] and 0.91 ± 0.24 mm [ACP_BED] at the implant apex, and between 1.68 and 2.35 degrees in angular deviation. Implant sites did not differ significantly, while some of the evaluation methods differed for shoulder and apex.
Conclusion: [REVERSE] revealed the smallest deviations between planned and actual implant position. 3D implant deviations were comparable with findings in the literature or even lower.
Keywords: digital light processing (DLP), 3D printing, static computer-aided implant surgery (s-CAIS), implant surgical guides, accuracy, trueness, evaluation methods
SciencePubMed ID (PMID): 35851355Pages 173-180, Language: English, GermanHennen, Melina Vivien / Blum, Hannah / Dammaschke, Till
Ziel: Die Genauigkeit und Reproduzierbarkeit von okklusalen Kontaktpunkten, die durch Artikulationsfolie (AF) visualisiert wurden, sollte untersucht und dann mit durch drei verschiedene intraorale Scanner (IOS) berechneten Kontaktpunkten verglichen werden.
Materialien und Methoden: Die okklusalen Kontaktpunkte wurden auf einem standardisierten Kunststoff-Zahnmodell unter Verwendung von AF 50 Mal mit maximaler Interkuspidation und konstanter Beißkraft visualisiert. Die Punkte wurden aus einer vertikalen Position über dem Modell fotografiert und am Bildschirm überlagert, um die Reproduzierbarkeit des Modells zu testen. Es folgte eine fünfzigfache Wiederholung durch Scans und Berechnung der okklusalen Kontaktpunkte durch die jeweiligen IOS CS3600 (ScanFlow v1 4. Version), TRIOS 3 (Basic 2019) und CEREC Omnicam (Software Version 5.1). Die Ergebnisse der Berechnung wurden mit Screenshots erfasst und dann mit den Fotos des AF überlagert. Die Bildüberlagerungen wurden in fünf Kategorien eingeteilt: Kategorie 1 = totale Überlappung der Kontaktpunkte, Kategorie 2 = teilweise Überlappung, Kategorie 3 = benachbarte Kontaktpunkte ohne Überlappung, Kategorie 4 = nur durch IOS identifizierte Kontaktpunkte, Kategorie 5 = nur durch AF identifizierte Kontaktpunkte. Alle Daten wurden statistisch ausgewertet (95% CI).
Ergebnisse: Insgesamt war die Visualisierung der okklusalen Kontaktpunkte durch die IOS im Vergleich zur AF signifikant ungenauer und weniger reproduzierbar (p < 0,05). In der Kombination von Sensitivität und Genauigkeit zeigte das TRIOS3 von 3Shape signifikant bessere Ergebnisse als die anderen getesteten IOS (p < 0,05).
Schlussfolgerung: In vitro zeigte die AF eine signifikant genauere Visualisierung der okklusalen Kontaktpunkte als die IOS.
Keywords: Artikulationsfolie, digitale intraorale Scanner, Okklusion, okklusaler Kontaktpunkt, Reproduzierbarkeit, Visualisierung
ApplicationPubMed ID (PMID): 35851356Pages 181-199, Language: English, GermanRasaie, Vanya / Abduo, Jaafar
The integration of modern technologies in removable prosthodontics in terms of complete denture fabrication has revolutionized fabrication procedures, improved outcomes, and led to advancements in denture materials. Numerous publications have described the digital techniques of complete denture fabrication. The steps described in these publications for the proposed digital workflow are diverse. This is suggestive of the flexibility of these modern techniques in terms of their integration with the steps of conventional protocols. Automated technologies have reduced the need for skilled manual work, while particular knowledge and a new skills set are required for both clinicians and dental technicians. Moreover, the effectiveness and efficacy of these modern technologies in complete denture fabrication are yet to be determined. To consolidate the existing literature on digital techniques of complete denture fabrication, this review summarizes the current digital workflows of the clinical and laboratory stages, describes the digital alternatives in each step, and discusses their advantages and limitations.
Keywords: complete denture, computer-aided design, computer-aided manufacturing, complete digital denture, digital dentistry, edentulous rehabilitation
ApplicationPubMed ID (PMID): 35851357Pages 201-219, Language: English, GermanGuo, Xueqiang / Jiang, Chunmiao / Liu, Xinqiang / Wang, Zheng
Completely digital design/completely digital manufacturing (CDD/CDM) workflows have been widely used in orthodontic and orthognathic treatments. This case report introduces a CDD/CDM workflow consisting of clear aligners and virtual planning for a surgery-first approach (SFA) in a patient with a skeletal Class III malocclusion. Following a shortened treatment time of 5 months, the patient’s facial appearance improved significantly, and well-balanced occlusion was obtained. SFAs with clear aligners can enable patients to achieve complete esthetic satisfaction during the therapeutic period. The CDD/CDM workflow provided accurate results, improved the clinical outcome, and reduced treatment time.
Keywords: surgery-first approach, virtual surgical planning, virtual orthodontic planning, clear aligners, skeletal Class III malocclusion, CAD/CAM
ApplicationPubMed ID (PMID): 35851358Pages 221-231, Language: English, GermanHerklotz, Insa / Kunz, Andreas / Stimmelmayr, Michael / Beuer, Florian
Ein FallberichtHintergrund: Die Versorgung des unbezahnten Oberkiefers mit einer Full-arch-Brücke auf vier sofortbelasteten Implantaten ist bereits als Behandlungsoption diskutiert worden, wenngleich in dieser Indikation normalerweise fünf Implantate empfohlen werden. Unabdingbare Voraussetzung für die Eingliederung eines vorgefertigten Provisoriums zum Zeitpunkt der Implantation ist ein präziser Transfer der virtuell geplanten Implantatpositionen durch eine dreidimensional geführte Implantatsetzung. Eine Dreipunktabstützung auf Zähnen und/oder Implantaten stellt den notwendigen stabilen Sitz der Implantatschablone während der Operation sicher.
Fallpräsentation: Im hier beschriebenen Fall erfolgte die Dreipunktabstützung auf Frontzähnen sowie temporären Implantaten in den Molarenregionen, die vor Aufnahme der DVT inseriert wurden. Während der virtuellen Implantatplanung wurde eine prothetisch möglichst günstige Implantatposition unter Nutzung des vorhandenen Knochens bestimmt, um umfangreiche Augmentationsmaßnahmen zu vermeiden. Anschließend wurde ein metallverstärktes Provisorium mithilfe einer Bohrschablone vorbereitet: Vier Implantate wurden, geführt durch eine zahn- und implantatgestützte Schablone, in den geplanten Positionen inseriert. Die prothetische Achse der anguliert gesetzten, distalen Implantate wird durch 17 Grad abgewinkelte Abutments ausgeglichen. Nach dem Transfer der Implantatposition in das Labor wurde das bereits vorbereitete Provisorium fertiggestellt. Die Restzähne wurden extrahiert und das Provisorium 3 Stunden nach der Implantation eingesetzt. Neun Monate später konnte die mikroverblendete Full-arch-Zirkonoxidbrücke unter stabilen Verhältnissen eingegliedert werden.
Schlussfolgerung: Die hohe Genauigkeit der Implantatplatzierung unter Verwendung einer Operationsschablone, die basierend auf der virtuellen präoperativen Implantatplanung hergestellt wird, führt zu einer relativ kurzen Behandlungsdauer und einer schnellen, unauffälligen Heilung mit geringen Beschwerden. Die prothetische Sofortrehabilitation ist nicht nur für den Patienten, sondern auch für das Behandlungsteam vorteilhaft. Mikroverblendetes monolithisches Zirkonoxid scheint als vielversprechende Option für verschraubte Full-arch-Brücken infrage zu kommen.
Keywords: geführte Implantatchirurgie, unbezahnter Kiefer, Backward-Planning, Sofortfunktion, digitaler Workflow