Mechanical Indicators of Primary Stability of Orthodontic Miniscrews: Effects of Pilot-Hole Diameter Across Three Commercial Systems with Different Thread External Diameters and Designs: An In Vitro Study
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Abstract
Background: Pre-drilling of pilot holes has been suggested to facilitate miniscrew placement in dense palatal bone. Objective: To compare mechanical indicators of primary stability (maximal insertion torque and pull-out strength) of miniscrew systems with different thread external diameters under varying pre-drilled pilot-hole diameters. Materials and methods: This study included 120 titanium alloy miniscrew implants with a thread length of 6.0 mm. The implants were classified into three groups according to thread external diameter (1.8, 1.9, and 2.0 mm). Each group was subdivided into four pilot-hole conditions: 0.0 mm (control), 1.1 mm, 1.2 mm, and 1.3 mm. All implants were inserted into synthetic composite palatal bone. Primary stability was evaluated by maximum insertion torque and vertical pull-out strength. Results: Both miniscrew system group and pre-drilled pilot-hole diameter significantly affected maximal insertion torque and pull-out strength (P < 0.001). A significant interaction between miniscrew system/design group and pilot-hole diameter was observed (P < 0.001). Maximal insertion torque decreased as pilot-hole diameter increased across all systems. The 2.0-mm system/design group consistently demonstrated the highest insertion torque under all drilling conditions. Pull-out strength remained relatively stable at 1.1-1.2 mm pilot-holes in the 1.8 mm system, whereas larger pilot-hole diameters resulted in significant reductions in some systems/designs. Conclusion: Both miniscrew implant design and pre-drilled pilot-hole diameter influence primary stability. Pilot-hole diameters of 1.1–1.2 mm provide an optimal balance between insertion torque and pull-out strength for 1.8–2.0 mm diameter miniscrews; however, the ideal pilot-hole size should be determined according to the specific miniscrew implant design.
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References
Chung KR, Nelson G, Kim SH, Kook YA. Severe bidentoalveolar protrusion treated with orthodontic microimplantdependent en-masse retraction. Am J Orthod Dentofacial Orthop 2007;132(1):105-15.
Chung KR, Kim SH, Choo H, Kook YA, Cope JB. Distalization of the mandibular dentition with mini-implants to correct a Class III malocclusion with a midline deviation. Am J Orthod Dentofacial Orthop 2010;137(1):135-46.
Miyawaki S, Koyama I, Inoue M, Mishima K, Sugahara T, Takano-Yamamoto T. Factors associated with the stability of titanium screws placed in the posterior region for orthodontic anchorage. Am J Orthod Dentofacial Orthop 2003;124(4):373-8.
Lim SA, Cha JY, Hwang CJ. Insertion torque of orthodontic miniscrews according to changes in shape, diameter and length. Angle Orthod 2008;78(2):234-40.
Motoyoshi M, Inaba M, Ono A, Ueno S, Shimizu N. The effect of cortical bone thickness on the stability of orthodontic mini-implants and on the stress distribution in surrounding bone. Int J Oral Maxillofac Surg 2009;38(1):13-8.
Gracco A, Giagnorio C, Incerti Parenti S, Alessandri Bonetti G, Siciliani G. Effects of thread shape on the pullout strength of miniscrews. Am J Orthod Dentofacial Orthop 2012;142(2):186-90.
Hou SM, Hsu CC, Wang JL, Chao CK, Lin J. Mechanical tests and finite element models for bone holding power of tibial locking screws. Clin Biomech (Bristol) 2004;19(7):738-45.
Carano A, Lonardo P, Velo S, Incorvati C. Mechanical properties of three different commercially available miniscrews for skeletal anchorage. Prog Orthod 2005;6(1): 82-97.
Sandler J, Benson PE, Doyle P, Majumder A, O’Dwyer J, Speight P, et al. Palatal implants are a good alternative to headgear: a randomized trial. Am J Orthod Dentofacial Orthop 2008;133(1):51-7.
Creekmore TD, Eklund MK. The possibility of skeletal anchorage. J Clin Orthod 1983;17(4):266-9.
Marquezan M, Mattos CT, Sant’Anna EF, de Souza MM, Maia LC. Does cortical thickness influence the primary stability of miniscrews?: A systematic review and meta-analysis. Angle Orthod 2014;84(6):1093-103.
Kravitz ND, Kusnoto B. Risks and complications of orthodontic miniscrews. Am J Orthod Dentofacial Orthop 2007;131(4 Suppl):S43-51.
Whang CZ, Bister D, Sherriff M. An in vitro investigation of peak insertion torque values of six commercially available mini-implants. Eur J Orthod 2011;33(6):660-6.
Motoyoshi M, Hirabayashi M, Uemura M, Shimizu N. Recommended placement torque when tightening an orthodontic mini-implant. Clin Oral Implants Res 2006;17(1):109-14.
Motoyoshi M. Clinical indices for orthodontic mini-implants. J Oral Sci 2011;53(4):407-12.
Papageorgiou SN, Zogakis IP, Papadopoulos MA. Failure rates and associated risk factors of orthodontic miniscrew implants: a meta-analysis. Am J Orthod Dentofacial Orthop 2012;142(5):577-95.e7.
Melsen B, Costa A. Immediate loading of implants used for orthodontic anchorage. Clin Orthod Res 2000;3(1):23-8.
Barros SE, Janson G, Chiqueto K, Garib DG, Janson M. Effect of mini-implant diameter on fracture risk and self-drilling efficacy. Am J Orthod Dentofacial Orthop 2011;140(4):e181-92.
Kim JW, Ahn SJ, Chang YI. Histomorphometric and mechanical analyses of the drill-free screw as orthodontic anchorage. Am J Orthod Dentofacial Orthop 2005;128(2):190-4.
Gupta N, Kotrashetti SM, Naik V. A comparitive clinical study between self tapping and drill free screws as a source of rigid orthodontic anchorage. J Maxillofac Oral Surg 2012;11(1):29-33.
Yi J, Ge M, Li M, Li C, Li Y, Li X, et al. Comparison of the success rate between self-drilling and self-tapping miniscrews: a systematic review and meta-analysis. Eur J Orthod 2017;39(3):287-93.
Chen YJ, Chang HH, Huang CY, Hung HC, Lai EH, Yao CC. A retrospective analysis of the failure rate of three different orthodontic skeletal anchorage systems. Clin Oral Implants Res 2007;18(6):768-75.
Büchter A, Wiechmann D, Koerdt S, Wiesmann HP, Piffko J, Meyer U. Load-related implant reaction of mini-implants used for orthodontic anchorage. Clin Oral Implants Res 2005;16(4):473-9.
Wilmes B, Rademacher C, Olthoff G, Drescher D. Parameters affecting primary stability of orthodontic mini-implants. J Orofac Orthop 2006;67(3):162-74.
Gantous A, Phillips JH. The effects of varying pilot hole size on the holding power of miniscrews and microscrews. Plast Reconstr Surg 1995;95(7):1165-9.
Phusantisampan P, Jotikasthira D, Jariyapongpaiboon P, Tripuwabhrut K. Effects of Pre-drilled Pilot-hole Diameters on Miniscrew Implant Primary Stability: An In vitro study. Chiang Mai Dental Journal 2020;41(3):13-22.
Winsauer H, Vlachojannis C, Bumann A, Vlachojannis J, Chrubasik S. Paramedian vertical palatal bone height for mini-implant insertion: a systematic review. Eur J Orthod 2014;36(5):541-9.
Hung E, Oliver D, Kim KB, Kyung HM, Buschang PH. Effects of pilot hole size and bone density on miniscrew implants’ stability. Clin Implant Dent Relat Res 2012;14(3):454-60.
Nguyen MV, Codrington J, Fletcher L, Dreyer CW, Sampson WJ. The influence of miniscrew insertion torque. Eur J Orthod 2018;40(1):37-44.
Di Leonardo B, Ludwig B, Lisson JA, Contardo L, Mura R, Hourfar J. Insertion torque values and success rates for paramedian insertion of orthodontic mini-implants : A retrospective study. J Orofac Orthop 2018;79(2):109-15.
