Stability and success rate of dual-thread miniscrews:

Abstract

Objectives To date, the clinical stability of dual-thread orthodontic miniscrews has not been studied. This study aimed to compare the primary stability and long-term clinical success rate of dual-thread and cylindrical orthodontic miniscrews and to examine the association between various clinical factors and the success rate of miniscrews. Materials and Methods A total of 145 cylindrical and 135 dual-thread miniscrews were inserted in the maxillary and mandibular buccal alveolar areas of 142 patients. The torque and Periotest (Siemens, Bensheim, Germany) values were recorded during insertion and removal. The effect of clinical variables such as sex, age, screw design, jaw, side of placement, root proximity, and site of placement on the success rate was examined using logistic regression analysis. Results There was no statistically significant difference (P = .595) in the overall clinical success rate between the two designs, with an overall success rate of 82.1% and 84.4% for the cylindrical and dual-thread miniscrews, respectively. Age and screw-root proximity were significantly associated with failure (P < .05). Conclusions The dual-thread miniscrews did not show superior long-term stability and clinical success rate as compared with the cylindrical miniscrews. The results of this study suggest that patient age and screw-root proximity influence the clinical success rate of miniscrews.

Revisiting the Complications of Orthodontic Miniscrew

“…The affection of sex was also found to be controversial. While some studies reported that there were no statistical differences [ 58 – 60 , 65 ], others reported that males had a higher success rate due to higher bone density [ 59 , 62 ].…”

“…Among risk factors from patients, the association between miniscrew failure and age was not consistent. Some studies showed no relationship between age and failure [58][59][60]; whereas others found that age could affect the miniscrew stability since there was poorer quality and higher bone turnover rate in growing patients compared to adults, affecting optimal mechanical miniscrew stability in adolescents [61][62][63][64][65]. Therefore, more attention should be taken to the miniscrew placement in younger patients.…”

The success rate of mini‐screws for incisors intrusion and patient age, gender, and insertion angle in the maxilla using CBCT and implant‐guided surgery. A split‐mouth, randomized control trail

“…In addition, the anchorage on micro‐implants prevents unwanted movements of tooth elements that were used in conventional orthodontic steps. Thus, offering an alternative optimal solution to orthognathic surgery in cases where dental anchorage may result in undesirable adverse effects such as vertical dimension changes produced by the use of conventional inter‐maxillary forces 2 …”

“…Additionally, it is believed that primary stability is essential for the success of mini‐screws 2,3 . Risk factors for the stability of mini‐screws can be divided into four categories: host‐related risks (age, sex, oral hygiene, cortical bone thickness, root proximity, and the location of the insertion ‘maxilla or mandible’, mini‐screw‐related risks (shape, diameter, and length of the screws), surgical management‐related risks (insertion torque, angle, placement height in the movable mucosa or attached gingiva, need for pre–drilling) 3–5 …”

Optimal Insertion Torque for Orthodontic Anchoring Screw Placement: A Comprehensive Review

“…A previous study used tapered, self-tapping, ϕ2.0 × 6 mm OASs, and reported ITs of 25.6 ± 5.5 Ncm [8], whereas another study used cylindrical, self-drilling, ϕ1.5 × 7 mm OASs in the maxillary buccal alveolar area and reported ITs of 6.0 ± 3.2 Ncm [9]. Thus, the IT values vary greatly with the placement method and OAS design (screw diameter, length, and tapered or cylindrical form) [1,[5][6][7][8][9][10][11][12][13][14][15]. Therefore, clinicians may be hesitant to apply these values in practice.…”