Evaluation of the success rate of single- and dual-thread orthodontic miniscrews inserted in the palatal side of the maxillary tuberosity.

BACKGROUND: Recent studies have reported that the placement of miniscrews for orthodontic anchorage in maxillary tuberosity is anatomically safe and can aid in achieving efficient tooth movement mechanically. However, the success rate of miniscrews placed on the palatal aspect of the maxillary tuberosity has not yet been elucidated. This study aimed to evaluate the success rate of single- and dual-thread miniscrews inserted in the palatal aspect of the maxillary tuberosity. METHODS: A total of 101 miniscrews (17 single-thread miniscrews: diameter 2.0 mm, length 10 mm; 84 dual-thread miniscrews: diameter 2.0 mm, length 12 mm) placed in 61 patients (6 males, 55 females; mean age = 30.9 ± 8.66 years) were retrospectively examined. Miniscrews that could be maintained for orthodontic anchorage for more than 6 months were considered successful. The direction of placement, bone-miniscrew contact (BMSC) rate, and survival of miniscrews were measured using cone-beam computed tomography. RESULTS: The overall success rate of single-thread miniscrews was 82.4% and that of dual-thread miniscrews was 94.0%. There was no significant difference in the overall clinical success rate between the two designs. Sex, mandibular plane angle, and malocclusion type did not significantly affect the success rate in both groups. CONCLUSIONS: Both single- and dual-thread miniscrews placed on the palatal aspect of the maxillary tuberosity showed high success and BMSC rates. However, there were no significant differences in the overall success rate and BMSC rate between the two miniscrew designs.

Is Inflammation a Friend or Foe for Orthodontic Treatment?: Inflammation in Orthodontically Induced Inflammatory Root Resorption and Accelerating Tooth Movement.

The aim of this paper is to provide a review on the role of inflammation in orthodontically induced inflammatory root resorption (OIIRR) and accelerating orthodontic tooth movement (AOTM) in orthodontic treatment. Orthodontic tooth movement (OTM) is stimulated by remodeling of the periodontal ligament (PDL) and alveolar bone. These remodeling activities and tooth displacement are involved in the occurrence of an inflammatory process in the periodontium, in response to orthodontic forces. Inflammatory mediators such as prostaglandins (PGs), interleukins (Ils; IL-1, -6, -17), the tumor necrosis factor (TNF)-α superfamily, and receptor activator of nuclear factor (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) are increased in the PDL during OTM. OIIRR is one of the accidental symptoms, and inflammatory mediators have been detected in resorbed roots, PDL, and alveolar bone exposed to heavy orthodontic force. Therefore, these inflammatory mediators are involved with the occurrence of OIIRR during orthodontic tooth movement. On the contrary, regional accelerating phenomenon (RAP) occurs after fractures and surgery such as osteotomies or bone grafting, and bone healing is accelerated by increasing osteoclasts and osteoblasts. Recently, tooth movement after surgical procedures such as corticotomy, corticision, piezocision, and micro-osteoperforation might be accelerated by RAP, which increases the bone metabolism. Therefore, inflammation may be involved in accelerated OTM (AOTM). The knowledge of inflammation during orthodontic treatment could be used in preventing OIIRR and AOTM.