OBJECTIVE: Using a commercial orthodontic treatment planning system, tooth movements were simulated to analyse how precise predefined movements can be determined by three different superimposition methods. Additionally, a retrospective analysis on clinical patient models before and after orthodontic treatment was performed to analyse possible differences in determination of clinical tooth movements with these methods.
METHODS: (1) A hexapod system was used to perform the tooth movements in physical maxillary dental models (N = 70). The initial and final situations were scanned, superimpositions executed, movements calculated, and their accuracy compared to the predefined movements was determined. (2) Digital three-dimensional (3D) maxillary dental models representing pre- and postorthodontic treatment situations (N = 100 patients) were superimposed. Selected tooth movements were calculated (N = 3600), and the results of the different superimposition methods were compared pairwise.
RESULTS: (1) The experimental study delivered only small location and scale shifts. Furthermore, concordance correlation coefficients above 0.99 for all three methods. This verified that all methods deliver values corresponding well to the predefined movements. (2) The retrospective analysis of the clinically performed orthodontic tooth movements comparing pairwise the three different methods intraindividually also showed small location and scale shifts. Furthermore, concordance correlation coefficients between 0.68 and 0.98 were observed, with only three of them below 0.8. This verified that the applied superimposition methods delivered values sufficiently close to each other.
CONCLUSIONS: As the experimental study showed very good agreement between the predefined and determined movements, and as the retrospective clinical study showed that the methods compared pairwise delivered values close to each other for the performed orthodontic tooth movements, it can be concluded that orthodontic tooth movements can be determined adequately correct by each of the examined methods.
UNASSIGNED: ZIELSETZUNG: Mittels eines kommerziellen Behandlungsplanungssystems wurden Zahnbewegungen simuliert, um zu analysieren, wie präzise vorgegebene Bewegungen mittels 3 verschiedener Überlagerungsmethoden ermittelt werden können. Zusätzlich wurde eine retrospektive Analyse mit Patientenmodellen durchgeführt, um zu analysieren, ob es Unterschiede zwischen diesen Methoden bei der Bestimmung klinischer Zahnbewegungen gibt.
METHODS: (1) Mithilfe eines Hexapodsystems wurden definierte Zahnbewegungen in Oberkiefermodellen durchgeführt (n = 70). Ausgangs- und Endposition der Zähne wurden gescannt, Überlagerungen durchgeführt, die Bewegungen errechnet und deren Übereinstimmung mit den vorgegebenen Bewegungen ermittelt. (2) Digitale 3‑D-Modelle des Oberkiefers vor und nach durchgeführten kieferorthopädischen Behandlungen (n = 100 Patienten) wurden überlagert, ausgewählte Bewegungen berechnet (n = 3600) und die Ergebnisse der verschiedenen Überlagerungsmethoden paarweise verglichen. ERGEBNISSE: (1) Die experimentelle Studie ergab lediglich kleine Ortsverschiebungen und Maßstabsänderungen. Die Konkordanz-Korrelationskoeffizienten lagen für alle 3 Verfahren über 0,99. Dies verifizierte, dass alle drei Methoden Werte liefern, die gut zu den vorgegebenen Bewegungen passen. (2) Die retrospektive Analyse der kieferorthopädischen Zahnbewegungen mittels intraindividueller paarweiser Vergleiche der unterschiedlichen Methoden zeigte ebenfalls kleine Ortsverschiebungen und Maßstabsänderungen, sowie Konkordanz-Korrelationsoeffizienten zwischen 0,68–0,98, mit nur dreien unter 0,8. Dies verifizierte, dass alle Überlagerungsmethoden hinreichend nahe beieinander liegende Werte liefern.
UNASSIGNED: Da die experimentelle Studie eine gute Übereinstimmung zwischen den vorgegebenen und den ermittelten Bewegungen zeigte und da die retrospektive Studie beim paarweisen Vergleich der Methoden nahe beieinander liegende Werte für die kieferorthopädischen Zahnbewegungen lieferte, kann geschlussfolgert werden, dass kieferorthopädische Zahnbewegungen mit jeder der untersuchten Methoden hinreichend korrekt ermittelt werden können.

BACKGROUND: The localization of lung nodules is challenging during thoracoscopy. In this study, we evaluated the use of three-dimensional (3D) lung reconstruction for use in the operating room to guide the identification of lung nodules during thoracoscopy.
METHODS: This was a single-center retrospective study. All consecutive patients undergoing thoracoscopic resection of lung nodules were included in the study. Patients were retrospectively divided into two groups based upon whether the thoracoscopic resection was performed with the assistance (3D group) or not (standard group) of 3D lung reconstruction. The operative time (minutes) to detect lung nodules was statistically compared between the two study groups in relation to the characteristics of lung nodules as size, localization, and distance from the visceral pleura.
RESULTS: Our study population consisted of 170 patients: 85 in the 3D group and 85 in the standard group. No intergroup difference differences were found regarding the characteristics and histological diagnosis of lesions. The standard group compared to the 3D group was associated with a significantly longer operative time for the detection of lesions <10 mm (13.87 ± 2.59 vs. 5.52 ± 1.01, p < 0.001), lesions between 10 and 20 mm (5.05 ± 0.84 vs. 3.89 ± 0.92; p = 0.03), lesions localized in complex segments (7.49 ± 4.25 vs. 5.11 ± 0.97; p < 0.001), and deep lesions (9.58 ± 4.82 vs. 5.4 ± 1.01, p < 0.001).
CONCLUSIONS: Our 3D lung reconstruction model for use in the operating room may be an additional tool for thoracic surgeons to guide the detection of small and deep nodules during thoracoscopy. It is a noninvasive and cost saving procedure and may be widely used.

OBJECTIVE: The purpose of this study was to assess the prevalence, distribution and intensity of tooth wear in a sample of an ancient Italian population in order to explain the pattern in terms of dietary habits and/or non-dietary tooth-use behaviors during the Early Bronze Age, with a focus on possible age-group and sex differences.
METHODS: Well-preserved permanent teeth of individuals from the Bronze Age site of Ballabio (Lecco) in northern Italy were examined for tooth wear by different methods. Eight 3D models of teeth at increasing severity of wear were created.
RESULTS: In total, 357 permanent teeth belonging to male and female individuals were included in the study. Dental wear was present in 96.6% of the total sample. Males showed significantly greater levels of wear than females in the mandibular teeth. Both sexes exhibited a significantly different wear direction between the anterior (oblique and flat) and posterior (oblique and concave) teeth. Significant age differences were observed in the direction and level of wear in the incisors, canines and premolars, with higher wear in the older group. Complete and rotatable virtual 3D images of different wear patterns are proposed.
CONCLUSIONS: The findings of the present study confirm the data from archaeological studies on this site and on northern Italian habits during the Early Bronze Age suggesting a diet rich in vegetables. The observed wear patterns can be related both to the diet of this Bronze age population, based on hard and abrasive food requiring vigorous mastication, and to sex differences in cultural practices.