ORIGINAL ARTICLE

.

.

. 8

mm , , 1.4 mm 1.6 mm 1.4 mm, 1.6

mm, 1.4 mm, 1.6 mm 4 . 20

, polyurethane foam .

.

. 1.6 mm 1.4 mm

. 1.4 mm

1.6 mm . ,

.

,

. 2006;36(4):275-83)

1

,1,2 onplant,3,4 5,6 ,

,7,8 .9,10

5

.11

.12

,13,14

.15

.

,

,

.16,17

36 4 , 2006

Table 1. Chemical composition and mechanical properties of Ti-6Al-4V alloy

.18 ,

,19,20

18

.

,

,21

polyurethane foam

.18 ,

.22

.

polyurethane foam

.

ASTM F2146-01 Ti-6Al-4V

alloy (Table 1)23

8 mm

(Myungsung, Seoul, Korea) .

,

1.4 mm 1.6 mm ,

1.4 mm, 1.6 mm,

1.4 mm, 1.6 mm

4 (Fig 1). 20

.

solid rigid polyurethane foam (Sawbones, Pacific

Research Laboratories, Vashon, WA, USA)

(Table 2, Fig 2, A)

1/8

(Elcomed SA200C, W&H,

Burmoos, Austria) (Fig 2, B) .

Vol. 36, No. 4, 2006. Korean J Orthod

Table 2. Mechanical properties of the solid rigid polyurethane foam (sawbones) for insertion of the orthodontic mini-implants

Fig 2. Material and equipment for insertion and removal of orthodontic mini-implants. A, solid rigid polyurethane foam

(sawbones) with homogeneous density (30 pcf); B, surgical engine (Elcomed SA200C) which is able to control the torque

and rpm, and measure the torque at an interval of 1/8 sec; C , insertion of orthodontic mini-implant into the solid rigid

polyurethane foam with the use of a surgical engine.

polyurethane foam

30 rpm

1 1/2

polyurethane foam

(Fig 1, C).18

,

( , 1/8 )

.

.

0 , 4

(2 ) , 8 (4 )

.

0 , 2 (1 ) , 4 (2 )

.

SPSS 12.0 for

windows release 12.0.1 (SPSS, Chicago, IL,

USA) ,

.

Kruskall-Wallis

,

Mann-Whitney .

4

1

Bonferroni correction

36 4 , 2006

Fig 3. Insertion and removal mean torque as a function of

the elapsed time for each group. A, Insertion mean torque;

B, removal mean torque.

.

(Fig 3, A).

1.6 mm,

1.4 mm (Table 3, Fig 3, A).

1.6 mm,

1.4 mm (Table 3, Fig 3, B).

1.4 mm 1.6 mm

1.4 mm 1.6 mm

.

.

,

, .

,

2 (1

) 4 (2 )

(Table 3, Fig 4).

1.4 mm

, 1.6 mm ,

Fig 4. Mean torque at 8, 4 and 0 seconds before the

maximum insertion torque and 0, 2 and 4 seconds after

the maximum removal torque of each group. One second

corresponds to a half turn of the mini-implant.

(Table 3).

, .

,24

,25

20

15

.18,21

,

.

(Fig 3),

,

.

Vol. 36, No. 4, 2006. Korean J Orthod

α

Table 3. Torque (Mean Ncm ± SD) at 8, 4 and 0 seconds before the maximum insertion torque and 0, 2 and 4 seconds

after the maximum removal torque of each group

.

polyurethane foam

.

.

.

.

.

36 4 , 2006

.

5-6

30 rpm 10-12 ,

10

12 , 14

.

10

12-14

26-28 7

.

.18

,

.

.

.

,

.

8 , 4

,

,

(Table 3).

4 , 2

,

4

.

,

.

,

,

.

,

.

2 , 4

.

polyurethane foam

.

5-6

2-3 .

polyurethane foam

4-5 4-5

, 8-10

.

.18

Vol. 36, No. 4, 2006. Korean J Orthod

.

,

.

1.4 mm 1.6 mm

.

2 , 1

7 Ncm

2

(p < 0.05) 4 , 2

5 Ncm

3

(p < 0.05). 4

.

36% ,

57% .

25

,

.

. 1.4 mm

.

.

,19

20

.

18

.

.

Ti-6Al-4V

alloy

grade 1 4 Ti alloy

. Ti-6Al-4V alloy

15

.

,

,

.

8 mm 1.4 mm 1.6 mm

polyurethane foam

.

1.

.

2. 1.6 mm 1.4 mm

.

3. 1.4 mm

36 4 , 2006

1.6 mm

.

4.

57% , 36%

.

,

.

.

1. Albrektsson T. Direct bone anchorage of dental implants. J Prosthet Dent

1983;50:255-61.

2. Linkow LI. The endosseous blade implant and its use in orthodontics.

Int J Orthod 1969;7:149-54.

3. Block MS, Hoffman DR. A new device for absolute anchorage for

orthodontics. Am J Orthod Dentofacial Orthop 1995;107:251-8.

4. Wehrbein H, Feifel H, Diedrich P. Palatal implant anchorage

reinforcement of posterior teeth: A prospective study. Am J Orthod

Dentofacial Orthop 1999;116:678-86.

5. Kanomi R. Mini-implant for orthodontic anchorage. J Clin Orthod

1997;31:763-7.

6. Umemori M, Sugawara J, Mitani H, Nagasaka H, Kawamura H. Skeletal

anchorage system for open-bite correction. Am J Orthod Dentofacial

Orthop 1999;115:166-74.

7. Park HS. A new protocol of the sliding mechanics with Micro-implant

Anchorage (MIA). Korean J Orthod 2000;30:677-85.

8. Kyung SH, Lim JK, Park YC. The use of miniscrew as an anchorage

for the orthodontic tooth movement. Korean J Orthod 2001;31:415-24.

9. Kim SJ, Lee YJ, Chung KR. An effect of immediate orthodontic force

on palatal endosseous appliance (C-Palatal Plate) in beagle dog. Korean

J Orthod 2003;33:91-102.

10. Kim CN, Sung JH, Kyung HM. Three-dimensional finite element

analysis of initial tooth displacement according to force application point

during maxillary six anterior teeth retraction using skeletal anchorage.

Korean J Orthod 2003;33:339-50.

11. Costa A, Raffainl M, Melsen B. Miniscrews as orthodontic anchorage:

a preliminary report. Int J Adult Orthodon Orthognath Surg 1998;13:

201-9.

12. Herrmann I, Lekholm U, Holm S, Kultje C. Evaluation of patient and

implant characteristics as potential prognostic factors for oral implant

failures. Int J Oral Maxillofac Implants 2005;20:220-30.

13. Himmlova L, Dostalova T, Kacovsky A, Konvickova S. Influence of

implant length and diameter on stress distribution: a finite element

analysis. J Prosthet Dent 2004;91:20-5.

14. Lim JW, Kim WS, Kim IK, Son CY, Byun HI. Three dimensional finite

element method for stress distribution on the length and diameter of

orthodontic miniscrew and cortical bone thickness. Korean J Orthod

2003;33:11-20.

15. Kim JW, Ahn SJ, Chang YI. Histomorphometric and mechanical analyses

of the drill-free screw as orthodontic anchorage. Am J Orthod

Dentofacial Orthop 2005;128:190-4.

16. Martinez H, Davarpanah M, Missika P, Celletti R, Lazzara R. Optimal

implant stabilization in low density bone. Clini Oral Implants Res

2001;12:423-32.

17. O'Sullivan D, Sennerby L, Meredith N. Influence of implant taper on the

primary and secondary stability of osseointegrated titanium implants. Clin

Oral Implants Res 2004;15:474-80.

18 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.

19. Hansson S, Werke M. The implant thread as a retention element in

cortical bone: the effect of thread size and thread profile: a finite element

study. J Biomech 2003;36:1247-58.

20. Palmer RM, Palmer PJ, Smith BJ. A 5-year prospective study of Astra

single tooth implants. Clin Oral Implants Res 2000;11: 179-82.

21. Ueda M, Matsuki M, Jacobsson M, Tjellstrom A. Relationship between

insertion torque and removal torque analyzed in fresh temporal bone. Int

J Oral Maxillofac Implants 1991;6:442-7.

22. Sennerby L, Dasmah A, Larsson B, Iverhed M. Bone tissue responses

to surface-modified zirconia implants: A histomorphometric and removal

torque study in the rabbit. Clin Implant Dent Relat Res 2005;7(Suppl

1):13S-20S.

23. Stephen DC, Jeanette ED. Biocompatibility and biofunctionality

materials: tissue response to implanted materials. In: Michael SB, John

NK. Endosseous implants for maxillofacial reconstruction. Phladelphia:

WB Saunders; 1995. p. 71.

24. Zdeblick TA, Kunz DN, Cooke ME, McCabe R. Pedicle screw pullout

strength. Correlation with insertional torque. Spine 1993;18:1673-6.

25. Ozawa T, Takahashi K, Yamagata M et al. Insertional torque of the

lumbar pedicle screw during surgery. J Orthop Sci 2005;10: 133-6.

26. Huiskes R, Nunamaker D. Local stresses and bone adaption around

orthopedic implants. Calcif Tissue Int 1984;36 (Suppl 1): 110S-7S.

ORIGINAL ARTICLE

Effect of dual pitch mini-implant design and diameter of an

orthodontic mini-implant on the insertion and removal torque

Jong-Wan Kim, DDS, MSD,a Il-Sik Cho, DDS,b Shin-Jae Lee, DDS, MSD, PhD,c

Tae-Woo Kim, DDS, MSD, PhD,d Young-Il Chang, DDS, MSD, PhDd

Objective: Small orthodontic mini-implants are useful as anchorage. However they have some

weaknesses such as loosening. This study was carried out to analyze the mechanical effects of the

dual pitch and diameter on the insertion and removal torque of mini-implants. Methods: The threads

of mini-implants were mono and dual pitch. The diameters of mini-implants were 1.4 mm and 1.6 mm.

Four groups were tested (mono 1.4 mm, mono 1.6 mm, dual 1.4 mm and dual 1.6 mm). All were

inserted and removed on polyurethane foam with the torques being measured. Results: The maximum

torque of the dual pitch groups was higher than the mono pitch groups during removal but lower during

insertion. The maximum torque of the 1.6 mm diameter groups was higher than the 1.4 mm diameter

groups during insertion and removal. The dual pitch 1.4 mm group showed the lowest insertion torque

but had similar or superior levels of removal torque to that of the mono pitch 1.6 mm group.

Conclusions: The dual pitch especially showed a continuous high removal torque after the peak.

Despite the small diameter, the dual pitch might improve the initial mechanical stability. (Korean J

Orthod 2006;36(4):275-83)

Key words: Orthodontic mini-implant, Stability, Dual pitch, Diameter