Journal List > Korean J Orthod > v.39(2) > 1043616

Yun and Lim: Effect of cutting flute length and shape on insertion and removal torque of orthodontic mini-implants

Abstract

Objective

The purpose of this study was to evaluate the effect of length and shape of cutting flute on mechanical properties of orthodontic mini-implants.

Methods

Three types of mini-implants with different flute patterns (Type A with 2.6 mm long flute, Type B with 3.9 mm long and straight flute, Type C with 3.9 mm long and helical flute) were inserted into the biomechanical test blocks (Sawbones Inc., USA) with 2 mm and 4 mm cortical bone thicknesses to test insertion and removal torque.

Results

In 4 mm cortical bone thickness, Type C mini-implants showed highest maximum insertion torque, then Type A and Type B in order. Type C also showed shortest total insertion time and highest maximum removal torque, but Type A and B didn't showed statistically significant difference in insertion time and removal torque. In 2 mm cortical bone thickness, there were no significant difference in total insertion time and maximum removal torque in three types of mini-implants, but maximum insertion torque of Type A was higher than two other Types of mini-implants.

Conclusions

Consideration about length and shape of cutting flute of mini-implant is also required when the placement site has thick cortical bone.

Figures and Tables

Fig 1
Three types of mini-implants used in this study (unit: mm).
kjod-39-95-g001
Fig 2
Torque tester (Biomaterials Korea Inc., Seoul, Korea).
kjod-39-95-g002
Fig 3
Graph showing the definition of maximum insertion torque and total insertion time.
kjod-39-95-g003
Fig 4
Graph showing the definition of maximum removal torque.
kjod-39-95-g004
Fig 5
Microscopic evaluation of removed mini-implant to check for any distortion of screw tip and threads. Type A (left); Type B (center); Type C (right).
kjod-39-95-g005
Fig 6
Total insertion time for each type of mini-implant. Type A, 2.6 mm long flute; Type B, 3.9 mm long and straight flute; Type C, 3.9 mm long and helical flute.
kjod-39-95-g006
Table 1
Mechanical properties of the biomechanical test block
kjod-39-95-i001
Table 2
Mean results and standard deviation (cortical bone thickness 2.0 mm)
kjod-39-95-i002

Type A, mini-implant with 2.6 mm long flute; Type B, mini-implant with 3.9 mm long and straight flute; Type C, mini-implant with 3.9 mm long and helical flute; NS, not significant; *Statically significant, p < 0.05; Significance determined by Tukey's test.

Table 3
Mean results and standard deviation (cortical bone thickness 4.0 mm)
kjod-39-95-i003

Type A, mini-implant with 2.6 mm long flute; Type B, mini-implant with 3.9 mm long and straight flute; Type C, mini-implant with 3.9 mm long and helical flute. Significance determined by Tukey's test. *Statically significant, p < 0.05.

References

1. Kanomi R. Mini-implant for orthodontic anchorage. J Clin Orthod. 1997. 31:763–767.
2. Costa A, Raffaini M, Melsen B. Miniscrews as orthodontic anchorage a preliminary report. Int J Adult Orthodon Orthognath Surg. 1998. 13:201–209.
3. Park HS. A new proctocol of the sliding mechanics with micro-implant anchorage (MIA). Korean J Orthod. 2000. 30:677–685.
4. Park HS. The skeletal cortical anchorage using titanium microscrew implants. Korean J Orthod. 1999. 29:699–706.
5. Oh MY, Chung KR, Kwon YD, Ryu DM, Lee BS. The clinical use of miniscrew for intraoral anchorage (1). J Korean Dent Assoc. 2000. 38:18–21.
6. Park HS, Jeong SH, Kwon OW. Factors affecting the clinical success of screw implants used as orthodontic anchorage. Am J Orthod Dentofacial Orthop. 2006. 130:18–25.
crossref
7. Moon CH, Lee DG, Lee HS, Im JS, Baek SH. Factors associated with the success rate of orthodontic miniscrews placed in the upper and lower posterior buccal region. Angle Orthod. 2008. 78:101–106.
crossref
8. Kuroda S, Sugawara Y, Deguchi T, Kyung HM, Takano-Yamamoto T. Clinical use of miniscrew implants as orthodontic anchorage: success rate and postoperative discomfort. Am J Orthod Dentofacial Orthop. 2007. 131:9–15.
crossref
9. Cheng SJ, Tseng IY, Lee JJ, Kok SH. A prospective study of the risk factors associated with failure of mini-implants used for orthodontic anchorage. Int J Oral Maxillofac Implants. 2004. 19:100–106.
10. Kuroda S, Yamada K, Deguchi T, Hashimoto T, Kyung HM, Takano-Yamamoto T. Root proximity is a major factor for screw failure in orthodontic anchorage. Am J Orthod Dentofacial Orthop. 2007. 131:Suppl 4. 68S–73S.
crossref
11. You ZH, Bell WH, Schneiderman ED, Ashman RB. Biomechanical properties of small bone screws. J Oral Maxillofac Surg. 1994. 52:1293–1302.
crossref
12. Kim JW, Cho IS, Lee SJ, Kim TW, Chang YI. Mechanical analysis of the taper shape and length of orthodontic mini-implant for initial stability. Korean J Orthod. 2006. 36:55–62.
13. Kim JW, Cho IS, Lee SJ, Kim TW, Chang YI. Effect of dual pitch mini-implant design and diameter of an orthodontic mini-implant on the insertion and removal torque. Korean J Orthod. 2006. 36:275–283.
14. Yano S, Motoyoshi M, Uemura M, Ono A, Shimizu N. Tapered orthodontic miniscrews induce bone-screw cohesion following immediate loading. Euro J Orthod. 2006. 28:541–546.
crossref
15. Song YY, Cha JY, Hwang CJ. Evaluation of insertion torque and pull-out strength of mini-screws according to different thickness of artificial cortical bone. Korean J Orthod. 2007. 37:5–15.
16. Lim SA, Cha JY, Hwang CJ. Insertion torque of orthodontic miniscrews according to changes in shape, diameter and length. Angle Orthod. 2008. 78:234–240.
crossref
17. Heidemann W, Gerlach KL, Gröbel KH, Köllner HG. Drill free screws: a new form of osteosynthesis screw. J Craniomaxillofac Surg. 1998. 26:163–168.
crossref
18. Heidemann W, Gerlach KL, Grobel KH, Kollner HG. Influence of different pilot hole sizes on torque measurements and pullout analysis of osteosynthesis screws. J Craniomaxillofac Surg. 1998. 26:50–55.
crossref
19. Kim JW, Ahn SJ, Chang YI. Histomorphometric and mechanical analysis of the drill-free screw as orthodontic anchorage. Am J Orthod Dentofacial Orthop. 2005. 128:190–194.
crossref
20. Kim JW, Chang YI. Effect of drilling process in stability of micro-implants used for orthodontic anchorage. Korean J Orthod. 2002. 32:107–115.
21. Kim YH, Choi JH. The study about retention of miniscrews used for intraoral anchorage. J Korean Dent Assoc. 2001. 39:684–687.
22. Ansell RH, Scales JT. A study of some factors which affect the strength of screws and their insertion and holding power in bone. J Biomech. 1968. 1:279–302.
crossref
23. Foley WL, Frost DE, Paulin WB Jr, Tucker MR. Uniaxial pullout evaluation of internal screw fixation. J Oral Maxillofac Surg. 1989. 47:277–280.
crossref
24. Evans M, Spencer M, Wang Q, White SH, Cunningham JL. Design and testing of external fixator bone screws. J Biomed Eng. 1990. 12:457–462.
crossref
25. Yerby S, Scott CC, Evans NJ, Messing KL, Carter DR. Effect of cutting flute design on cortical bone screw insertion torque and pullout strength. J Orthop Trauma. 2001. 15:216–221.
crossref
26. Wikenheiser MA, Markel MD, Lewallen DG, Chao EYS. Thermal response and torque resistance of five cortical half-pins under simulated insertion technique. J Orthop Res. 1665. 13:615–619.
crossref
27. Koistinen A, Santavirta SS, Kröger H, Lappalainen R. Effect of bone mineral density and amorphous diamond coatings on insertion torque of bone screws. Biomaterials. 2005. 26:5687–5694.
crossref
28. Seebeck J, Goldhahn J, Städele H, Messer P, Morlock MM, Schneider E. Effect of cortical thickness and cancellous bone density on the holding strength of internal fixator screws. J Orthop Res. 2004. 22:1237–1242.
crossref
29. Deguchi T, Nasu M, Murakami K, Yabuuchi T, Kamioka H, Takano-Yamamoto T. Quantitative evaluation of cortical bone thickness with computed tomographic scanning for orthodontic implants. Am J Orthod Dentofacial Orthop. 2006. 129:721.e7–721.e12.
crossref
30. Liou EJW, Chen PH, Wang YC, Lin JC. A computed tomographic image study on the thickness of the infrazygomatic crest of the maxilla and its clinical implications for miniscrew insertion. Am J Orthod Dentofacial Orthop. 2007. 131:352–356.
crossref
31. Motoyoshi M, Hirabayashi M, Uemura M, Shimizu N. Recommended placement torque when tightening an orthodontic mini-implant. Clin Oral Implants Res. 2006. 17:109–114.
crossref
TOOLS
Similar articles