Bicortical titanium screws for critical orthodontic anchorage in the mandible: a preliminary report on clinical applications

Abstract

Critical anchorage during orthodontic treatment in the mandible needs both time and effort and patient compliance. In 8 patients, 12 bicortical titanium screws (BIS) were used as anchorage units for orthodontic molar protraction. The criteria for patient selection were: critical anchorage in the lower jaw (i.e. retraction of anterior teeth undesirable) and molar extraction sites. After insertion of the screws in local anesthesia, orthodontic forces were applied immediately. One screw worked loose and had to be removed before the end of treatment. Problems encountered included impingement of the screw head and slight inflammatory reactions of the surrounding mobile mucosa, which necessitated premature removal of two screws. After healing, a new insertion site was chosen. Further treatment was uneventful. Anchorage for orthodontic forces as described offers several advantages. The total treatment time is reduced as the screws can be loaded immediately. The line of action of the orthodontic force coincides with the level of the center of resistance of the molar resulting in a favorable translatory tooth movement. Treatment does not depend on patient cooperation.

Impact of Insertion Depth and Predrilling Diameter on Primary Stability of Orthodontic Mini-implants

“…[1][2][3][4][5][6][7] However, failure rates of approximately 10%-30% as described in the literature are still not satisfactory. [8][9][10][11] A sufficient primary stability measured by insertion torque seems to play a major role for the treatment time survival rate.…”

Success Rate and Risk Factors Associated with Mini-Implants Reinstalled in the Maxilla

“…[1][2][3][4][5] According to experimental and clinical studies, OMIs can provide sufficient and stable anchorage for orthodontic treatment. 2,[6][7][8][9][10] However, the success rates of OMIs have been reported to range from 37% to 97%. [11][12][13][14][15][16][17][18][19][20][21][22] Studies have found that the stability of OMIs is affected by age, sex, craniofacial skeletal pattern, site and side of implantation, latent period, loading protocol, dimension of OMI, angulation of OMI to bone, insertion torque, degree of OMI-bone contact, quality and quantity of the cortical bone, degree of inflammation of the peri-OMI tissue, thickness and mobility of the soft tissue, and root proximity.…”

Is miniscrew primary stability influenced by bone density?

“…1,2 It is achieved by mechanical contact between the miniscrew surface and bone 3 and depends on the characteristics of devices 4,5 , insertion technique 4 and bone quality and quantity of the receptor site. 4,[6][7][8] The primary stability plays an important role in the successful secondary stability of miniscrews, since lack of immediate stability can lead to progressive mobility of the device and its subsequent loss. 9 In clinical use, the initial stability of miniscrews is also considered essential, because of immediate or early load applied on them in many patients.…”