The orthodontic treatment of palatal impacted maxillary central incisors with guide rod appliance

Objective To analyze the effects and features of guide rod appliance on palatal impacted central incisors.Methods 7 palatal impacted central incisors were treated with guide rod appliance,the normal erupted contralateral central incisors were used as control.Pre-and Posttreatment panoramic radiograph were measured and the following data were collected:(1) The length of the impacted central incisors and the contralateral control teeth; (2) The length of the anatomical roots; (3) The length of the anatomical crowns; (4) Root/Crown length ratio.The measures were compared using two sample t-test with SPSS17.0.Results Six impacted central incisors were treated to normal position.Their pulp and periodontal attachment were normal.The length of the impacted central incisors was 4.00 mm shorter than the control group (P=0.020).The ratio of Root/Crown length is 1.36 ± 0.31,which is smaller than that of the control group (P =0.048).One tooth demonstrated ankylosis for that 16 months of orthodontic extrusion showed no movement and gave up treatment.Conclusions The length of the impacted tooth's root was acceptable after treatment.The guide rod appliance is an effective method to treat palatal impacted central incisors. Key words: Guide rod appliance;  Impacted tooth;  Central incisors