Influence of material choice on the force delivery of bimaxillary tooth positioners on canine malpositions

Influence of material choice on the force delivery of bimaxillary tooth positioners on canine malpositions

Objective Since their introduction in 1945, tooth positioners have been used to treat a range of malpositions. Although the original appliance was made of natural rubber, today’s tooth positioners are fabricated from various elastic, transparent materials. It was the aim of this study to evaluate th...

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Bibliographic Details
Published in:Journal of orofacial orthopedics Vol. 73; no. 2; pp. 104 - 115
Main Authors: Lochmatter, D., Steineck, M., Brauchli, L.
Format: Journal Article
Language:English
Published: Berlin/Heidelberg Springer-Verlag 01-04-2012
Subjects:
Activator Appliances
Cuspid - abnormalities
Cuspid - physiopathology
Dental Stress Analysis
Dentistry
Humans
In Vitro Techniques
Malocclusion - physiopathology
Malocclusion - therapy
Maxilla - physiopathology
Medicine
Oral and Maxillofacial Surgery
Original Article
Orthodontic Appliances, Removable
Orthodontics, Corrective - methods
Robotics
Tooth Movement Techniques
Torque
Eckzahn
Positioner
Moment
Force
Drehmoment
Material
Kraft
Canine
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Summary:Objective Since their introduction in 1945, tooth positioners have been used to treat a range of malpositions. Although the original appliance was made of natural rubber, today’s tooth positioners are fabricated from various elastic, transparent materials. It was the aim of this study to evaluate the forces and moments produced by current positioners on various upper canine malpositions. Material and methods Seven positioners of different materials were tested on 11 upper canine malpositions: 0.25, 0.5, 1 mm supraposition; 0.25, 0.5, 1 mm infraposition; 5°, 10°, 20° mesiorotation; 5° mesioinclination, 5° buccal root torque. We measured forces and moments in vitro after bite closure by 0.5 mm, and opening by 1 mm using a three-dimensional robotic device. All measurements were taken in a temperature-controlled environment at 36 °C. Results The forces and moments measured at the canine varied greatly among the different positioners, with the thermoformed EVA positioner showing much greater forces and moments in almost all malpositions. At initial closure, we observed intrusive forces of 6–32 N for suprapositions, 0–11 N intrusive forces for infrapositions, 0–20 Nmm for mesiorotations, 6–12 Nmm for mesioinclinations, and − 23 Nmm to 5 Nmm for buccal root torque. All positioners were most effective on suprapositioned teeth. Very low or negligible correctional forces and moments in conjunction with all infrapositions and 5° with rotation were noted. Labial root torque led to unpredictable moments. Conclusion Positioner material plays a major role in delivering forces to the teeth. However, tooth positioners did not induce corrective forces in all the malpositions tested. Clinically relevant correctional forces or moments in conjunction with all suprapositions, rotations of 10° and 20° as well as mesial tipping of the canine were observed.
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ISSN:1434-5293
1615-6714
DOI:10.1007/s00056-011-0067-7