Â
Figure 5. Torque-time curves of the MK3 and MK4. a Insertion torque. b Removal torque
Figure 4. Torque-time curves of the TE. a Insertion torque. b Removal torque
Â
Figure 3. Torque-time curves of the BL. a Insertion torque. b Removal torque
Â
Â
Figure 2. Torque-time curves of the ST. a Insertion torque. b Removal torque
Figure 1. Compressed longitudinally to one third for characteristics of implant design. ST Straumann standard implant, MK3 Nobel Biocare MKIII, BL Straumann bone level implant, TE Straumann tapered effect implant, MK4 Nobel Biocare MKIV. Outer surface of implant (solid line). Inner surface of implant (dotted line)
Figure 1. Compressed longitudinally to one third for characteristics of implant d...
Â
Initial area
Parallel area
Tapered area
Platform area
ST6
1.42 ± 0.43
0.31 ± 0.14
–
–
ST8
3.57 ± 1.62
0.35 ± 0.09
–
–
ST10
2.49 ± 0.81
0.45 ± 0.05
–
–
BL8
2.16 ± 0.21
0.50 ± 0.08
2.32 ± 0.52
–
BL10
1.96 ± 0.49
0.35+0.04
2.45+0.23
–
BL12
1.82 ± 0.27
0.33 ±â€...
Code
Insertion torque
Removal torque
Effective thread length (ETL)
(N · cm)
(N · cm)
(×π mm)
ST6
6.19 ± 0.716
5.95 ± 0.718
11.53
ST8
8.06 ± 1.038
9.09 ± 1.093
15.11
ST10
13.13 ± 1.763
12.37 ± 1.746
21.48
BL8
17.67 ± 1.290
16.67 ± 2.140
20.88
BL10
23.56 ± 1.628
21.99 ± 1.530
31....
System
Length
Pitch
Lead
Code
Manufacturer
(mm)
(mm)
(mm)
Standard RN
6, 8, 10
1.2
1.2
ST
Straumann
Bone Level RC
8, 10, 12
0.8
0.8
BL
Straumann
Tapered Effect RN
10
0.8
0.8
TE
Straumann
Brånemark MKIII
10
0.6
1.2
MK3
Nobel Biocare
Brånemark MKIV
10
0.6
1.2
MK4
Nobel Biocare
Abbreviations
BL:
Bone Level RC
IT:
insertion torque value
MK3:
Brånemark MKIII
MK4:
Brånemark MKIV
RT:
removal torque value
ST:
Standard RN
TE:
Tapered Effect RN
References
Friberg B, Sennerby L, Roos J, Johansson P, Strid CG, Lekholm U. Evaluation of bone density using cutting resistance measurements and microradiography. An...
Influence of cortical bone
The reason why a simulation test for only cancellous bone without cortical bone was performed in the present study has already been described. It was reported that bone density and the ratio of cortical bone and cancellous bone have influence on the primary stability of an implant and that higher primary stability is achieved with thread, even at the slightest lev...
Although the removal torque curves measured in the present study had similar shapes to one another, they were divided into two groups upon detailed observation, comprising a group of ST with parallel only, and a group of BL, TE, MK3, and MK4 having tapers and platforms. Since the thread contacts the artificial bone sequentially at the time of insertion, the torque curves showed the character...
This indicates that the friction at the time of rotating and pressing is greater than that at the time of rotating and cutting the bones with a tap and is a reasonable result. In the parallel area, the torque curve was a line with a moderate gradient, and the torque rise rate obtained from the gradient of the line was 0.36 N · cm/s. From this, it is estimated that the torque increase w...
Discussion
Insertion torque curve
In 2000, O’Sullivan reported torque curves for a prosthetic implant for the first time, and evaluated the characteristics of the tapered type by torque curves obtained by inserting five kinds of implants into the maxillary bone of unembalmed human cadavers. In a subsequent review, Meredith cited six kinds of torque curves when the final osteotomy diamete...
For the TE, the lower part of the implant was parallel and the lateral surface and axial surface had the same taper in the cervical region. TE10 in Fig. 4a showed a torque curve with a similar form to BL10 in Fig. 3 and had three kinds of areas. The torque curves for MK3 and MK4 in Fig. 4a had an area in which the torque finally rose suddenly after reaching its critical point and became moderate...
Results
Insertion torque
The insertion torque curve was divided into four regions. The first was the region where the torque rose suddenly immediately after insertion, which was seen in all implant bodies (shown as ① in the figure, and hereinafter called the initial area). The second was the region where the torque rose linearly with a moderate gradient, which was seen in all implant bodie...
Methods
Implants
The type of implant used for the experiments and the characteristics of its design are shown in Table 1 and Fig. 1, respectively. Figure 1 shows that the implant is compressed longitudinally to one third. The outer surface of the implant is indicated with a solid line, and the inner surface of the implant is indicated with a dotted line.
Preparation of an implant socket in ...
Background
Primary stability following implant placement is an essential condition for osseointegration. The primary stability is affected by the implant design, including surface-modifying or implant cavity-forming techniques, as well as by the bone quantity and bone density of the patient. In recent years, the interest of implant manufacturers and clinicians has shifted to the acquisition of ...
Abstract
Background
Primary stability following implant placement is essential for osseointegration and is affected by both implant design and bone density. The aim of this study was to compare the relationships between torque-time curves and implant designs in a poor bone quality model.
Methods
Nine implant designs, with five implants in each category, were compared. A total of 90 implants ...