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Frictional resistance exerted by different lingual and labial brackets: an in vitro study.

Lombardo L, Wierusz W, Toscano D, Lapenta R, Kaplan A, Siciliani G - Prog Orthod (2013)

Bottom Line: The effect of various factors, namely bracket/base width, slot size, inter-bracket distance, and first- (ΘcI) and second-order (ΘcII) critical contact angles were evaluated and compared.The maximum force necessary to displace NiTi wires of two different diameters (0.012, 0.014) was measured, using both elastic and metal ligatures with conventional brackets.The frictional force necessary to displace the wires increased as the diameter of the wire increased in all tested brackets (p<0.01).

View Article: PubMed Central - PubMed

Affiliation: Postgraduate School of Orthodontics, University of Ferrara, Ferrara, Italy. lulombardo@tiscali.it.

ABSTRACT

Background: Although much has been written on the implications of friction generated between orthodontic archwires and labial brackets, information on lingual brackets is still limited. Hence, we set out to investigate the frictional resistance exerted by different lingual and labial brackets, including both conventional and self-ligating designs. The effect of various factors, namely bracket/base width, slot size, inter-bracket distance, and first- (ΘcI) and second-order (ΘcII) critical contact angles were evaluated and compared.

Methods: A plaster model of a pretreatment oral cavity was replicated to provide 18 (9 upper and 9 lower) identical versions. The anterior segments of each were taken, and the canine and lateral and central incisors were mounted with either lingual (7th Generation, STb, New STb, In-Ovation L, ORJ) or labial (Mini-Mono, Mini Diamond, G&H Ceramic) brackets. Mechanical friction tests were performed on each type of bracket using a universal testing machine. The maximum force necessary to displace NiTi wires of two different diameters (0.012, 0.014) was measured, using both elastic and metal ligatures with conventional brackets.

Results: The frictional force necessary to displace the wires increased as the diameter of the wire increased in all tested brackets (p<0.01). Friction was significantly higher (p<0.001) with elastic ligatures, as compared with metal ones, in all conventional brackets. In the lower lingual group, significantly lower friction was generated at conventional lingual New STb brackets (p<0.01) and ORJ lingual brackets (p<0.05) than at self-ligating In-Ovation L lingual brackets. A significant statistical correlation between (ΘcI) and friction was detected in the lower labial bracket group.

Conclusions: Friction resistance is influenced not only by the bracket type, type of ligation, and wire diameter but also by geometric differences in the brackets themselves.

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Caterpillar plot: effect on friction for different types of brackets. The straight lines represent the confidence intervals (CI) of the friction generated at each bracket, keeping the other variables constant (wire and ligature). If two different brackets have overlapping CIs, these brackets have a significantly different effect on friction.
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Fig7: Caterpillar plot: effect on friction for different types of brackets. The straight lines represent the confidence intervals (CI) of the friction generated at each bracket, keeping the other variables constant (wire and ligature). If two different brackets have overlapping CIs, these brackets have a significantly different effect on friction.

Mentions: The linear mixed model revealed that the different types of brackets had different effects on friction (Figure 7). In the Lower lingual group, keeping the other variables constant (wire and ligature), the In-Ovation L bracket produced higher values of frictional forces as compared to New STb.Figure 7


Frictional resistance exerted by different lingual and labial brackets: an in vitro study.

Lombardo L, Wierusz W, Toscano D, Lapenta R, Kaplan A, Siciliani G - Prog Orthod (2013)

Caterpillar plot: effect on friction for different types of brackets. The straight lines represent the confidence intervals (CI) of the friction generated at each bracket, keeping the other variables constant (wire and ligature). If two different brackets have overlapping CIs, these brackets have a significantly different effect on friction.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384939&req=5

Fig7: Caterpillar plot: effect on friction for different types of brackets. The straight lines represent the confidence intervals (CI) of the friction generated at each bracket, keeping the other variables constant (wire and ligature). If two different brackets have overlapping CIs, these brackets have a significantly different effect on friction.
Mentions: The linear mixed model revealed that the different types of brackets had different effects on friction (Figure 7). In the Lower lingual group, keeping the other variables constant (wire and ligature), the In-Ovation L bracket produced higher values of frictional forces as compared to New STb.Figure 7

Bottom Line: The effect of various factors, namely bracket/base width, slot size, inter-bracket distance, and first- (ΘcI) and second-order (ΘcII) critical contact angles were evaluated and compared.The maximum force necessary to displace NiTi wires of two different diameters (0.012, 0.014) was measured, using both elastic and metal ligatures with conventional brackets.The frictional force necessary to displace the wires increased as the diameter of the wire increased in all tested brackets (p<0.01).

View Article: PubMed Central - PubMed

Affiliation: Postgraduate School of Orthodontics, University of Ferrara, Ferrara, Italy. lulombardo@tiscali.it.

ABSTRACT

Background: Although much has been written on the implications of friction generated between orthodontic archwires and labial brackets, information on lingual brackets is still limited. Hence, we set out to investigate the frictional resistance exerted by different lingual and labial brackets, including both conventional and self-ligating designs. The effect of various factors, namely bracket/base width, slot size, inter-bracket distance, and first- (ΘcI) and second-order (ΘcII) critical contact angles were evaluated and compared.

Methods: A plaster model of a pretreatment oral cavity was replicated to provide 18 (9 upper and 9 lower) identical versions. The anterior segments of each were taken, and the canine and lateral and central incisors were mounted with either lingual (7th Generation, STb, New STb, In-Ovation L, ORJ) or labial (Mini-Mono, Mini Diamond, G&H Ceramic) brackets. Mechanical friction tests were performed on each type of bracket using a universal testing machine. The maximum force necessary to displace NiTi wires of two different diameters (0.012, 0.014) was measured, using both elastic and metal ligatures with conventional brackets.

Results: The frictional force necessary to displace the wires increased as the diameter of the wire increased in all tested brackets (p<0.01). Friction was significantly higher (p<0.001) with elastic ligatures, as compared with metal ones, in all conventional brackets. In the lower lingual group, significantly lower friction was generated at conventional lingual New STb brackets (p<0.01) and ORJ lingual brackets (p<0.05) than at self-ligating In-Ovation L lingual brackets. A significant statistical correlation between (ΘcI) and friction was detected in the lower labial bracket group.

Conclusions: Friction resistance is influenced not only by the bracket type, type of ligation, and wire diameter but also by geometric differences in the brackets themselves.

Show MeSH