Evaluation of the effects of zygoma anchorage system on canine retraction in extraction cases

ABSTRACTEvaluation Of The Effects Of Zygoma Anchorage System On CanineRetraction In Extraction CasesThe aim of this study was to compare effects of the PG retraction spring used withand without the zygoma anchorage system on canine retraction.For this purpose, 30 patients in postpubertal development stages, having AngleCI-I or CI-II malocclusions, whose upper first premolars were indicated to beextracted and requiring maximum or moderate anchorage were included in thisstudy. The patients were divided into two groups, each consisting of 15 subjects.The implant assisted group comprised of maximum anchorage cases (9 female, 6male with a mean age of 16 years 8 month) and zygoma anchorage systems wereplaced in left and right zygomatic buttress regions to improve posterior anchoragewhile PG retraction springs were used for canine retraction. On the other hand,moderate anchorage cases (10 female, 5 male with a mean age of 15 years 5month) were included in the second group, which was subjected to PG retractionsprings for canine retraction without using zygoma anchorage. Dental cast modelsand lateral cephalometric radiographs were obtained at the initial and final stagesof canine retraction and were used in the comparison of the groups for the effectsof zygoma anchorage on canine retraction. Cephalometric and dental castmeasurements were evaluated statistically.While the anchorage loss was more evident in the group where PG retractionsprings were used without anchorage reinforcement, both groups showedsignificant anchorage loss. No significant differences were observed betweengroups for canine retraction speed, sagittal and vertical movements of canines.Key Words: Canine retraction, PG retraction spring, anchorage, zygomaanchorage system, mini plate