[Comparison of two treatment method for maxillary incisors intrusion]

To compare the clinical effects of miniscrews and conventional utility arch in the maxillary incisors intrusion.

Twenty adult patients with III degree deep bite were chosen and divided into two groups randomly. The cephalometric films, intraoral periapical radiographies with metal guide bars, and periodontium parameters were taken before and after intrusion. The major measurement items included alteration of the maxillary first molar in vertical dimension, torque and length of maxillary central incisors, overbite, clinical crown of maxillary central incisors, probing depth (PD), gingival index (GI), plaque index (PI) and etc. PASW statistics 18.0 was used for statistical analysis.

In the miniscrew group, there was no change of U1-SN, U6-PP distance, U6-SN(P<0.05), but significant reductions in overbite and U1-Stm distance(P<0.05). The probing depth (PD) increased(P<0.05), and the width of keratinized gingiva(WKG) decreased significantly(P<0.05). In the conventional utility arch group, significant differences were found in U1-SN, U6-SN, OP-SN, PLI2(P<0.05). There was no difference in periodontal supporting tissue changes between the two groups(P>0.05).

Compared with the conventional utility arch, minisrew has advantages on intruding upper incisors, and improving lip-tooth relationships. Less treatment period is needed in the minisrew group, and the impact on periodontal supporting tissue is similar.