Comparison of micro-implant screw anchorage at various implant areas

Huixia ZHOU; Zengquan WANG; Chunhuo HUANG; Xinghua YU

ABSTRACT

BACKGROUND:

Micro-implant screws as an absolute anchorage, instead of traditional anchorage that requires patient's high matching and affects beauty, has been paid more attention.

OBJECTIVE:

To compare the changes in 3 different places following implantation of micro-implant screws. DESIGN, TIME AND

SETTING:

The controlled study was performed at the Hospital of Stomatology Affiliated to Foshan College of Sciences and Technology from January 2004 to December 2007.

PARTICIPANTS:

A total of 45 patients who demand powerful anchorage during the orthodontic treatment were assigned to 3 groups free gingiva group, mucogingival junction group, and mucosa group.

METHODS:

By using incomplete flap micro-implant screw implantation, micro-implant screws were implanted in the free gingiva, mucogingival junction and mucosa, with 30 screws in each area.MAIN OUTCOME

MEASURES:

Loosening and defluvium of micro-implant screws were measured. Pain duration and degree were determined in patients undergoing implantation of micro-implant screws 7 days following surgery. Soft tissue surrounding the micro-implant screws and bleeding rate during probing were detected 56 days following surgery.

RESULTS:

The number of screw loosening was greatest in the free gingiva group (9 screws), while lowest in the mucogingival junction group (2 screws). Patients suffered from severe flare and pain in the mucosa, and the reaction was mild in the free gingiva following implantation. The reaction was not obvious, but severe pain was found in the mucogingival junction following implantation compared with the free gingiva. Soft tissue surrounding the micro-implant screws and bleeding rate during probing were greater in the mucosa group than in the free gingiva group and mucogingival junction group (P<0.05).

CONCLUSION:

The incomplete flap micro-implant screws in the mucogingival junction contribute to the increase in success implantation rate and the decrease in inflammatory degree, and prevent the occurrence of potential risk.