EditorialDOI: 10.3290/j.ijcd.b5139819, PubMed ID (PMID): 38530271Pages 3-4, Language: English, GermanBeuer, Florian
ScienceDOI: 10.3290/j.ijcd.b3836589, PubMed ID (PMID): 36695628Pages 9-18, Language: English, GermanLee, Younghoo / Jung, Youngchul / Choi, Yeawon / Kim, Yuyeon / Kim, Sangbaek / Hong, Seoung-Jin / Kim, HyeongSeob / Pae, Ahran
Aim: To compare the accuracy of three impression methods by comparing the distance between the reference points of the implant fixture, especially in curved maxillary anterior teeth.
Materials and methods: Implant fixtures were placed in the maxillary central incisor and canine regions. A maxillary master cast was made using a model scanner and 3D printer. Ten impressions were taken from the three experimental groups constructed (group P: pick-up impression coping; group I: scan body with an intraoral scanner; group B: bite impression coping). The distance between the reference points, the angle between the scan bodies, and displacement of the 3D surface area were measured.
Results: The distances between the reference points were significantly different between groups I and B in the maxillary incisors, and between group P and the other two groups in the maxillary canines. Group P had the least amount of displacement in both fixtures. Both fixtures showed the highest displacement in group B. Displacement of the 3D surface area in the maxillary incisors showed no significant difference between the groups. There was a significant difference in the maxillary canines between groups P and I.
Conclusions: In the present study, all three implant impression methods showed changes in the position and angle of the fixture compared with the master cast. The highest accuracy was shown by the impression method using the pick-up impression coping, but the impression method using the intraoral scanner also showed clinically acceptable accuracy. It should be noted that errors may occur when taking impressions using a bite impression coping.
Keywords: implant impression, implant angulation, bite impression coping, scan body, intraoral scanner
ScienceDOI: 10.3290/j.ijcd.b3916775, PubMed ID (PMID): 36815624Pages 19-26, Language: English, GermanWillmann, Claire / Deschamps, Adrien / Taddei-Gross, Corinne / Musset, Anne-Marie / Lai, Cecilia / Etienne, Olivier
Aim: The aim of the present in vivo study was to compare the clinical trueness of primary mucostatic impressions obtained either by a classical alginate or an optical intraoral scanner technique in patients with a fully edentulous maxilla.
Materials and methods: A total of 30 patients with a fully edentulous maxilla were included in the study and underwent both conventional impressions and intraoral optical impressions (Trios 3). The conventional impressions were casted and the resulting plaster casts were digitized using a desktop scanner (Imetric D104i). These digitized impressions were superimposed over the optical impressions to compare the differences between the two data sets. Statistical analyses were performed to identify relevant deviations.
Results: For the 30 intraoral impressions, 80.88% of the surface areas were below the tolerance threshold of 25 µm and were thus considered similar to the areas scanned with the desktop scanner from the reference plaster cast. Interestingly, the differences (19.12% of the surface areas) were localized in depressible areas such as the vestibule, soft palate, incisive papilla, and flabby ridges. These locations were consistent with the mean of positive differences of +22.8 µm, indicating deformation or less compression with the use of the intraoral scanner.
Conclusions: The digital primary impression of the fully edentulous maxilla can be considered similar to the conventional alginate impression except in the depressible areas. Considering the mucostatic objective of such a primary impression, one may consider the optical impression to be more accurate than the conventional one.
Keywords: digital impression, conventional impression, intraoral scanner, clinical trial, edentulous patients, maxilla
ScienceDOI: 10.3290/j.ijcd.b3963071, PubMed ID (PMID): 36928756Pages 27-35, Language: English, GermanMonaco, Carlo / Arena, Antonio / Marziali, Andrea / Consolo, Ugo
Aim: The present in vitro study aimed to evaluate the depth of reading of intraoral scanners (IOSs) within the gingival sulcus.
Materials and methods: A knife-edge preparation for a full crown was performed on a Frasaco model. The gingival sulcus of the scanned model was modified using a dedicated software program (Model Creator, exocad DentalCAD 2.4 Plovdiv) by setting the apical width (AW), coronal width (CW), and gingival sulcus depth (D). Two dental models with different gingival sulcus depths (1 or 2 mm) were printed using the digital light processing (DLP) technique. Each model was scanned 10 times. Seven different IOSs were used: Emerald, Trios 3, Carestream 3600, Dental Wings DWIO, CondorScan, True Definition Scanner (TDS), and Cerec Omnicam. Measurements of D values were performed using 3Shape 3D viewer software. The normality of the data distribution was evaluated using the Shapiro-Wilk test (P < 0.05). The nonparametric Levene’s test was used to check for homoscedasticity. The data were statistically analyzed using the Kruskal-Wallis test (α = 0.05) and the Nemenyi test.
Results: All IOSs were able to read within the 1-mm–deep gingival sulcus, albeit with some statistically significant differences (P < 0.001). TDS and Trios 3 were able to read within the 2-mm–deep gingival sulcus (P < 0.001).
Conclusions: The depth of reading of different IOSs can vary significantly. In the model with a 2-mm gingival sulcus, even in the absence of oral fluids, the depth of reading was incomplete, suggesting that deep preparations into the gingival sulcus are difficult to detect with IOSs.
Keywords: intraoral scanner (IOS), gingival sulcus, depth of reading, knife-edge preparation, digital light processing
ScienceDOI: 10.3290/j.ijcd.b3916781, PubMed ID (PMID): 36811289Pages 37-48, Language: English, GermanChen, Junpeng / Wang, Jing / Wang, Yang / Wang, Diancan / Xu, Xiangliang / Guo, Chuanbin
Ziel: Mit vorliegenden Studie sollten die Merkmale der Gelenkkinematik bei Patienten mit Kondylusrekonstruktion anhand einer Simulation ihrer Unterkieferbewegungen untersucht werden, die auf einer intraoralen Registrierung mittels Kieferregistriersystem und Intraoralscanner basierte.
Material und Methode: In die Studie wurden Patienten, bei denen eine unilaterale Unterkiefer-Segmentektomie und Kondylusrekonstruktion mit autogenem Knochen durchgeführt wurde, sowie gesunde Freiwillige aufgenommen. Die Eingruppierung erfolgte nach rekonstruierten bzw. nicht rekonstruierten Kondylen. Mit einem Kieferregistriersystem (zebris) wurden zunächst die Unterkieferbewegungen aufgezeichnet. Anhand dieses Registrats wurde die Gelenkkinematik in einem Modell simuliert. Die Neigung der Bahn des Kondylenpunktes, die Grenzbewegungen, die Kieferdeviation und der Kauzyklus wurden analysiert. Schließlich wurden ein t-Test und eine einfaktorielle Varianzanalyse durchgeführt.
Ergebnisse: Insgesamt wurden 20 Patienten, davon 6 mit Kondylusrekonstruktion und 14 mit Erhaltung des Kondylus, sowie 10 gesunde Freiwillige inkludiert. Die Patienten mit Kondylusrekonstruktion zeigten insgesamt flachere Bewegungsbahnen der Kondylenpunkte: Der mittlere Neigungswinkel dieser Bewegungsbahnen während der maximalen Kieferöffnung war nach einer Kondylusrekonstruktion (0,57 ± 12,54°) signifikant kleiner als nach einer Kondyluserhaltung (24,70 ± 3,90, p = 0,014), ebenso der Neigungswinkel während der Protrusion (Kondylusrekonstruktion: 7,04 ± 12,21°, Kondyluserhaltung: 31,12 ± 6,79°, p = 0,022). Bei den gesunden Freiwilligen betrug der Neigungswinkel der Kondylusbahn bei maximaler Kieferöffnung 16,81 ± 3,97° und in Protrusion 21,54 ± 2,80°, ohne statistische Signifikanz der Unterschiede zu den Patienten. Der Kondylus der betroffenen Seite neigte bei allen Patienten während der Kieferöffnung und Protrusion zu einer Deviation nach lateral. Patienten mit rekonstruiertem Kondylus wiesen eine stärkere Einschränkung der Mundöffnung und der Unterkieferbewegungen sowie kürzere Kauzyklen auf als Patienten mit erhaltenem Kondylus.
Schlussfolgerung: Patienten, die eine Kondylusrekonstruktion erhalten hatten zeigten flachere Bewegungsbahnen der Kondyluspunkte, einen größeren Umfang lateraler Bewegungen und kürzere Kauzyklen als Patienten mit erhaltenem Kondylus. Die verwendete Methode der Simulation der Unterkieferbewegungen auf Grundlage einer intraoralen Registrierung mittels Kieferregistriersystem und Intraoralscanner war in der Lage die Kondylenbewegungen adäquat zu simulieren.
Keywords: Digitaltechnik, patientenspezifische Modellierung, Elektromyografie, Unterkiefertumor, Unterkieferzyklus, Bewegungsumfang, Kiefergelenk
ScienceDOI: 10.3290/j.ijcd.b3945153, PubMed ID (PMID): 36928754Pages 49-86, Language: English, GermanChowdhary, Ramesh / Sonnahalli, Nithin Kumar
Statement of the problem: Occlusion is associated with all disciplines of dentistry and plays a major role in the longevity of both implant- and tooth-borne restorations. Achieving occlusal harmony ensures balance is established between the dental and myofascial structures, which can be measurably established to high numerical tolerances with the T-Scan digital occlusal analysis system.
Purpose: To describe and evaluate the known and proven applications of T-Scan digital occlusal analysis in various dental practice disciplines through a systematic review of the literature.
Materials and methods: An electronic, English-language PubMed/MEDLINE and Cochrane Central Registry of Controlled Trials database search using the keywords “T-Scan,” “TMD,” “Occlusion,” “Implant Protected Occlusion,” and “Orthodontics” was conducted without any date restrictions. The related journal findings were hand searched to determine studies that met the eligibility criteria for inclusion in the present systematic review.
Results: The PubMed/MEDLINE search identified 423 articles. After removing duplicates, the titles and abstracts of the remaining 421 studies were screened. 274 ineligible articles were excluded, leaving 147 articles. Of those, 33 articles were not in English, 27 full-text articles were not available, 4 were comments and letters to editors, 1 was a review, and 2 described techniques. A total of 86 articles met the eligibility criteria for inclusion.
Conclusion: Much scientific evidence supports the use of T-Scan, as it measures relative occlusal contact forces and the time sequence durations of occlusal contacts objectively, accurately, and repeatedly for improved treatment outcomes. The system’s hardware, sensor, and software evolution from T-Scan I to today’s T-Scan 10 Novus system has overcome early sensor and system drawbacks to improve the clinical performance of T-Scan in many disciplines of dental medicine.
Keywords: T-Scan, digital occlusal analysis
ScienceDOI: 10.3290/j.ijcd.b3916799, PubMed ID (PMID): 36811290Pages 89-97, Language: English, GermanHofmann, Paul / Kunz, Andreas / Schmidt, Franziska / Beuer, Florian / Duddeck, Dirk
Purpose: A reference method for quantifying contaminations on two-piece abutments manufactured using CAD/CAM has not yet been established. In the present in vitro study, a pixel-based machine learning (ML) method for detecting contamination on customized two-piece abutments was investigated and embedded in a semiautomated quantification pipeline.
Materials and methods: Forty-nine CAD/CAM zirconia abutments were fabricated and bonded to a prefabricated titanium base. All samples were analyzed for contamination by scanning electron microscopy (SEM) imaging followed by pixel-based ML and thresholding (SW) for contamination detection; quantification was performed in the postprocessing pipeline. Wilcoxon signed-rank test and Bland-Altmann plot were applied to compare both methods. The contaminated area fraction was recorded as a percentage.
Results: There was no statistically significant difference between the percentages of contamination areas (median = 0.004) measured with ML (median = 0.008) and with SW (median = 0.012), asymptotic Wilcoxon test: P = 0.22. The Bland-Altmann plot demonstrated a mean difference of -0.006% (95% confidence interval [CI] from -0.011% to 0.0001%) with increased values from a contamination area fraction of > 0.03% for ML.
Conclusion: Both segmentation methods showed comparable results in evaluating surface cleanliness; pixel-based ML is a promising assessment tool for detecting external contaminations on zirconia abutments. Further studies are required to investigate the clinical performance of this tool.
Keywords: computer-aided design, scanning electron microscopy, machine learning, ultrasonics, hygiene, dental implant abutments
ApplicationDOI: 10.3290/j.ijcd.b5004083, PubMed ID (PMID): 38530272Pages 99-107, Language: English, GermanSykara, Maria / Ntovas, Panagiotis / Markou, Nikolaos / Madianos, Phoebus / Vassilopoulos, Spyridon
Aim: The purpose of this study was to present the use of computer-assisted periodontal surgery utilizing a novel surgical guide for cases with severe gingival enlargement through a clinical application in a patient with hereditary gingival fibromatosis.
Materials and methods: The treatment plan included nonsurgical periodontal therapy, surgical periodontal treatment, and regular periodontal maintenance before the initiation of orthodontic treatment. Due to the increased soft tissue thickness, a surgical guide with a novel design was fabricated to facilitate the periodontal surgery since most of the patient’s teeth were malpositioned and underexposed due to fibromatosis. For this purpose, the patient’s intraoral scan was merged with a CBCT image in order to plan surgical excisions based on the anatomy of the teeth and the bone contour.
Results: The customized surgical guide facilitated the gingivectomy by controlling not only the shape of the initial incisions but also their orientation toward the level of the cementoenamel junction, improving the efficiency of the clinical time compared with freehand surgery and assisting in the verification of the final soft tissue shape, based on the treatment plan.
Conclusion: Digital technology through the superimposition of multiple data sets can assist in the diagnosis and multidisciplinary management of cases with gingival fibromatosis. The proposed design of the surgical guide can facilitate soft tissue surgery based on the digital treatment plan, leading to more predictable management of the soft tissue, especially in patients with severe gingival enlargement, as in cases with hereditary gingival fibromatosis or drug-induced gingival overgrowth
Keywords: periodontal surgery, 3D surgical guide, hereditary gingival fibromatosis, surgical crown lengthening, digital data set
ApplicationDOI: 10.3290/j.ijcd.b4144909, PubMed ID (PMID): 37283190Pages 109-125, Language: English, GermanFracchia, David Emilio / Franchini, Leonardo / Rocca, Giovanni Tommaso / Saratti, Carlo Massimo
Ziel: Die vorliegende Studie sollte zeigen, dass sich mithilfe volldigitaler Workflows ästhetische und funktionelle Ergebnisse zuverlässig realisieren lassen.
Material und Methode: Dieser klinische Fallbericht dokumentiert alle Behandlungsschritte einer ästhetischen Gesamtrehabilitation mit adhäsiven No-prep-Restaurationen, die volldigital geplant und durchgeführt wurde. Nach Abklärung der Wünsche und Bedürfnisse des Patienten wurde zunächst ein Behandlungsplan erstellt, der alle funktionellen und ästhetischen Anforderungen des Falls berücksichtigte. Auf Basis einer digitalen Überlagerung von 2-D-Bilddaten, 3-D-Modellen und einem Gesichtsscan des Patienten konnte eine verbindliche Planung und Vorschau der neuen dentalen Ästhetik erstellt werden, wobei für die oberen Frontzähne eine „Copy-and-Paste“-Technik zum Einsatz kam.
Schlussfolgerung: Das Ergebnis der Gesamtrehabilitation war ästhetisch und funktionell zufriedenstellend und durch gesundes Weichgewebe gekennzeichnet.
Keywords: Zahnverschleiß, Gesamtrehabilitation, Okklusion, digitaler Workflow, Ästhetik, digitales Wax-up, Gesichtsscan