Comparative photoelastic study of dental and skeletal anchorages in the canine retraction.
OBJECTIVE
To compare dental and skeletal anchorages in mandibular canine retraction by means of a stress distribution analysis.


METHODS
A photoelastic model was produced from second molar to canine, without the first premolar, and mandibular canine retraction was simulated by a rubber band tied to two types of anchorage: dental anchorage, in the first molar attached to adjacent teeth, and skeletal anchorage with a hook simulating the mini-implant. The forces were applied 10 times and observed in a circular polariscope. The stresses located in the mandibular canine were recorded in 7 regions. The Mann-Whitney test was employed to compare the stress in each region and between both anchorage systems. The stresses in the mandibular canine periradicular regions were compared by the Kruskal-Wallis test.


RESULTS
Stresses were similar in the cervical region and the middle third. In the apical third, the stresses associated with skeletal anchorage were higher than the stresses associated with dental anchorage. The results of the Kruskal-Wallis test showed that the highest stresses were identified in the cervical-distal, apical-distal, and apex regions with the use of dental anchorage; and in the apical-distal, apical-mesial, cervical-distal, and apex regions with the use of skeletal anchorage.


CONCLUSIONS
The use of skeletal anchorage in canine retraction caused greater stress in the apical third than the use of dental anchorage, which indicates an intrusive component resulting from the direction of the force due to the position of the mini-implant and the bracket hook of the canine.
Cristiane Aparecida
CA
de Assis Claro
Rosana Villela
RV
Chagas
Ana Christina Elias Claro
AC
Neves
Laís Regiane
LR
da Silva-Concílio
D001696:Biomechanical Phenomena; D003481:Cuspid / Q000473:pathology*; D015921:Dental Implants; D006801:Humans; D008334:Mandible; D003765:Models, Dental; D008963:Molar / Q000473:pathology; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation* / Q000379:methods; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D019516:Orthodontic Space Closure / Q000295:instrumentation; D009969:Orthodontic Wires; D013314:Stress, Mechanical; D019227:Tooth Apex / Q000473:pathology; D019237:Tooth Cervix / Q000473:pathology; D014087:Tooth Movement Techniques / Q000295:instrumentation*; D014092:Tooth Root / Q000473:pathology
D015921:Dental Implants
Orthodontic anchorage; Orthodontics; Procedures; Tooth movement