Introduzione Lo scopo di questo studio era fornire alcune indicazioni cliniche in relazione agli elastici interarcata più idonei da utilizzare nella meccaniche di Classe III. Pertanto, questo studio è stato condotto con i seguenti obiettivi: 1) valutare le distanze medie inter-arcata sul piano sagittale a cui vengono tesi gli elastici di Classe III, 2) analizzare le forze rilasciate a quelle distanze utilizzando elastici forniti da diversi produttori e 3) confrontare le forze dichiarate e rilasciate a secco e in ambiente umido. Materiali e metodi 37 pazienti di Classe III sono stati selezionati retrospettivamente. I loro modelli digitali sono stati utilizzati per lo studio. Il software 3Shape Ortho® Viewer è stato utilizzato per misurare le distanze tra i punti dell'asse facciale (FA) dei primi molari superiori e dei canini inferiori (A), dei primi molari superiori e dei primi premolari inferiori (B), dei primi molari superiori e dei secondi premolari inferiori (C), secondi premolari superiori e canini inferiori (D), primi premolari superiori e canini inferiori (E). Sono stati esaminati elastici da 1/8, 3/16, 1/4, 5/16 e 3/8 di pollici - 2 once, 2.5 once, 3 once, 3.5 once, 4 once, 4.5 once, 5.5 once, 6 once, 6.5 once e 8 once di 3 diverse marche (Ormco, American Orthodontics e 3M), alle distanze sopra indicate. Il sistema MTS è stato utilizzato per tendere gli elastici e per registrare le forze rilasciate. Le registrazioni sono state eseguite a secco (T0) e in umido, dopo 1 ora (T1), 6 ore (T2) e 12 ore (T3) di immersione in saliva artificiale. La misurazione a T0 è stata confrontata con la forza dichiarata dai produttori, le misurazioni a T1, T2 e T3 sono state confrontate con i valori T0. Risultati Le distanze medie erano: A = 29.13 mm (SD 1.94), B = 21.55 mm (SD 2.15), C = 14.72 mm (SD 2.28), D = 20.49 mm (SD 1.79), E = 13.98 mm (SD 1.79). Sono state riscontrate differenze significative (p <0.05) tra forze misurate e forze dichiarate dai produttori e la maggior parte degli elastici ha mostrato una significativa diminuzione della forza (p <0.05) dopo 1h, 6h e 12h di immersione in saliva artificiale. Conclusioni Sebbene la maggior parte degli elastici abbia mostrato valori di forza diversi da quelli dichiarati dai produttori, gli elastici con valori di forza medio-alta (4.5 once, 6 once, 8 once) sembrano i più affidabili poiché mostrano una significativa diminuzione della forza dopo 12 ore di immersione in saliva artificiale. Considerando i risultati, le forze dichiarate in elastici di 1/8 e 3/16 di pollici e 4.5, 6 e 8 once hanno mostrato una maggiore affidabilità nel tempo.
Introduction The aim of this study was to provide some clinical indications in relation to the right interarch elastics to use in Class III mechanics. Therefore, this study was conducted with the following goals: 1) to assess the medium inter-arch distances in the sagittal plane at which Class III elastics are stretched, 2) to analyze the released forces at those distances using elastics provided by different manufacturers and 3) to compare declared and released forces in dry and wet environments. Materials and methods 37 Class III patients were selected retrospectively. Their digital models were used for the study. 3Shape Ortho® Viewer software was used to measure the distances between the facial axes (FA) points of upper first molars and lower canines (A), upper first molars and lower first premolars (B), upper first molars and lower second premolars (C), upper second premolars and lower canines (D), upper first premolars and lower canines (E). 1/8, 3/16, 1/4, 5/16 and 3/8 inches – 2 oz, 2.5 oz, 3 oz, 3.5 oz, 4 oz, 4.5oz, 5.5oz, 6 oz, 6.5 oz and 8oz elastics from 3 different brands (Ormco, American Orthodontics and 3M) were tested at the above mentioned distances. The MTS system was used to stretch the elastics and to record the released forces. Recordings were performed in dry (T0) and wet conditions, after 1h (T1), 6h (T2) and 12h (T3) of artificial saliva immersion. While T0 measurement was compared with the producers’ declared force, T1, T2 and T3 measurements were compared with T0 values. Results Mean distances were: A=29.13mm (SD 1.94), B=21.55mm (SD 2.15), C=14.72mm (SD 2.28), D=20.49mm (SD 1.79), E=13.98mm (SD 1.79). Significant differences (p<0.05) were reported between the measured forces and the producers’ declared forces and most of the elastics showed a significant force loss after 1h, 6h and 12 h of artificial saliva immersion (p<0.05). Conclusions Although most of the tested elastics showed different force values with respect to those declared by manufacturers, elastics with medium-heavy force (4.5 oz, 6 oz, 8 oz) seemed to be the most reliable. They showed a significant force decay after 12 hours of artificial saliva immersion. Considering the overall results, 1/8 inches and 3/16 inches elastics with 4.5 oz, 6 oz, and 8 oz declared forces showed the most reliable force over time.
LE MECCANICHE DI CLASSE III CON ELASTICI INTERARCATA: UN’ANALISI IN VITRO DELLA FORZA RILASCIATA.
DILIBERTO, FABIO
2019/2020
Abstract
Introduction The aim of this study was to provide some clinical indications in relation to the right interarch elastics to use in Class III mechanics. Therefore, this study was conducted with the following goals: 1) to assess the medium inter-arch distances in the sagittal plane at which Class III elastics are stretched, 2) to analyze the released forces at those distances using elastics provided by different manufacturers and 3) to compare declared and released forces in dry and wet environments. Materials and methods 37 Class III patients were selected retrospectively. Their digital models were used for the study. 3Shape Ortho® Viewer software was used to measure the distances between the facial axes (FA) points of upper first molars and lower canines (A), upper first molars and lower first premolars (B), upper first molars and lower second premolars (C), upper second premolars and lower canines (D), upper first premolars and lower canines (E). 1/8, 3/16, 1/4, 5/16 and 3/8 inches – 2 oz, 2.5 oz, 3 oz, 3.5 oz, 4 oz, 4.5oz, 5.5oz, 6 oz, 6.5 oz and 8oz elastics from 3 different brands (Ormco, American Orthodontics and 3M) were tested at the above mentioned distances. The MTS system was used to stretch the elastics and to record the released forces. Recordings were performed in dry (T0) and wet conditions, after 1h (T1), 6h (T2) and 12h (T3) of artificial saliva immersion. While T0 measurement was compared with the producers’ declared force, T1, T2 and T3 measurements were compared with T0 values. Results Mean distances were: A=29.13mm (SD 1.94), B=21.55mm (SD 2.15), C=14.72mm (SD 2.28), D=20.49mm (SD 1.79), E=13.98mm (SD 1.79). Significant differences (p<0.05) were reported between the measured forces and the producers’ declared forces and most of the elastics showed a significant force loss after 1h, 6h and 12 h of artificial saliva immersion (p<0.05). Conclusions Although most of the tested elastics showed different force values with respect to those declared by manufacturers, elastics with medium-heavy force (4.5 oz, 6 oz, 8 oz) seemed to be the most reliable. They showed a significant force decay after 12 hours of artificial saliva immersion. Considering the overall results, 1/8 inches and 3/16 inches elastics with 4.5 oz, 6 oz, and 8 oz declared forces showed the most reliable force over time.| File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.14240/30511