Evidence-based selection of orthodontic miniscrews, increasing their success rate in the mandibular buccal shelf. A randomized, prospective clinical trial

Abstract

Background Skeletal anchorage has made it possible to perform complex orthodontic tooth movements that are difficult or even impossible to achieve with conventional orthodontic treatment. Mandibular buccal shelf miniscrews, used for distalization, play a particularly important role in treatment of Class III malocclusion. Unfortunately, stability of the miniscrews placed in the mandible is still considered at higher risk of failure compared to other intraoral locations. The aim of our study was to determine the influence of the miniscrew size on their long-term stability, occurrence of oral mucosa inflammation and pain lasting over 48 h after implantation. Methods 184 Absoanchor® miniscrews (Dentos, South Korea) in two sizes: SH2018-10 (length 10 mm, ø 1.8–2.0 mm) and SH1514-08 (length 8 mm, ø 1.4–1.5 mm) were inserted in the mandibular buccal shelf in 92 Caucasians aged 20–50 years, diagnosed with Class III malocclusion that required en-masse distalization of the mandibular dentition. Data was statistically analyzed with the level of significance set at p = .05. Results 91.3% of the SH2018-10 and 75% of the SH1514-08 miniscrews were stable, and this difference was statistically significant (p < .05). Inflammation of the oral mucosa was noticed around both types of miniscrews and affected 50% of the SH2018-10 and 26.09% of the SH1514-08 group (p < .05). Pain lasting longer than 48 h after implantation was related to 60.87% and 20.65% of the SH2018-10 and the SH1514-08 miniscrews (p < .05), respectively. Inflammation associated with larger SH2018-10 miniscrews did not affect their stability (p > .05), contrary to the SH1514-08 ones (p < .05). When inflammation was present, the overall success rate declined to 64.29%, from 94.74% noted for TADs without inflammation. According to the log-rank test, smaller TADs failed significantly sooner than the larger ones (p = .002). Conclusion Larger SH2018-10 miniscrews are the anchorage of choice for the mandibular buccal shelf, despite triggering inflammation and long-lasting pain significantly more often than the smaller ones. Therefore, this issue should be discussed with every patient prior to miniscrew use. Trial registration ID: ClinicalTrials.gov Identifier: NCT05280678 Date of Registration: 15/03/2022. Retrospectively registered.

Indication and Success Rates of Skeletal Anchorage System in Orthodontics

“…As reported in the evidence, the overall success rate of palatal implants is 91.5% (27) with significantly low failure rates http://dx.doi.org/10.52533/JOHS.2023.31202 (28,29). The success rate of buccal shelf implants was also similar, at 91.3% (30). On the contrary, the 12-month survival rates of palatal and buccal shelf implants were considerably different: 90.9% for palatal and 31.3% for buccal shelf implants (27).…”

Success rates of single-thread and double-thread orthodontic miniscrews in the maxillary arch

“…The success rate of miniscrews ranges from 60 to 93% [ 10 , 11 ], which is lower than osseointegrated implants (96–99%) [ 3 ]. Various factors influence the success rate of miniscrews, including bone quality and quantity at the insertion site, smoking, screw diameter and length, thread design, surgical technique, jaw, and oral hygiene status [ 3 , 6 , 7 , 12 ].…”