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Figure 12. Equivalent stresses at (a) the neck and...

Figure 12. Equivalent stresses at (a) the neck and (b) the tip of the implant. Figure 12. Equivalent stresses at (a) the neck and (b) the tip of the implant.

Figure 11. The distribution of equivalent stress (...

Figure 11. The distribution of equivalent stress (MPa) around the first molar. Figure 11. The distribution of equivalent stress (MPa) around the first molar.

Figure 10. Displacement in the inferior-superior d...

Figure 10. Displacement in the inferior-superior direction (z-axis). (a) The contact model and (b) the fixation model. Figure 10. Displacement in the inferior-superior direction (z-axis). (a) The contact model and (b) the fixation model.

Figure 9. Displacement in the mesiodistal directio...

Figure 9. Displacement in the mesiodistal direction (y-axis). (a) The contact model and (b) the fixation model. Figure 9. Displacement in the mesiodistal direction (y-axis). (a) The contact model and (b) the fixation model.

Figure 8. Displacement in the buccolingual directi...

Figure 8. Displacement in the buccolingual direction (x-axis). (a) The contact model and (b) the fixation model. Figure 8. Displacement in the buccolingual direction (x-axis). (a) The contact model and (b) the fixation model.

Figure 7. The displacement of the three implants. ...

Figure 7. The displacement of the three implants. (M) Mesial side, (D) Distal side, (B) Buccal side, and (L) Lingual side are shown. Figure 7. The displacement of the three implants. (M) Mesial side, (D) Distal side, (B) Buccal side, and (L) Lingual side are shown.

Figure 6. Implant displacement under loading condi...

Figure 6. Implant displacement under loading conditions. Figure 6. Implant displacement under loading conditions.

Figure 5. An FEA model. (a) Buccal loading, (b) ce...

Figure 5. An FEA model. (a) Buccal loading, (b) central loading, and (c) lingual loading are shown. Figure 5. An FEA model. (a) Buccal loading, (b) central loading, and (c) lingual loading are shown.

Figure 4. An experimental model loading test. : A ...

Figure 4. An experimental model loading test. Figure 4. An experimental model loading test.

Figure 3. An experimental model. (a) Buccal loadin...

Figure 3. An experimental model. (a) Buccal loading, (b) central loading, and (c) lingual loading are shown. Figure 3. An experimental model. (a) Buccal loading, (b) central loading, and (c) lingual loading are shown.

Figure 2. Three implants were embedded in an artif...

Figure 2. Three implants were embedded in an artificial mandible. Figure 2. Three implants were embedded in an artificial mandible.

Figure 1. An artificial mandible. : A biomechanica...

Figure 1. An artificial mandible. Figure 1. An artificial mandible.

Table 7 Coefficients o...

Model Loading points Buccal loading Central loading Lingual loading Average The neck of the implant  Contact model   No. 34 9.62 ...

Table 6 Three-way ANOV...

Source Sum of squares df Mean squared F value p value The neck of the implant  A: Boundary conditions 64.725 1 ...

Table 5 Three-way ANOV...

Source Sum of squares df Mean squared F value p value Contact model  A: Observed area 22.324 1 22.324 ...

Table 4 Three-way ANOV...

Source Sum of squares df Mean squared F value p value Contact model  A: Observed area 116.630 1 116.63...

Table 3 Three-way ANOV...

Source Sum of squares df Mean squared F value p value Contact model  A: Observed area 16.346 1 16.346 ...

Table 2 Coefficients of ...

Model Loading Average Buccal loading Central loading Lingual loading Experimental model 2.49 4.76 4.90 4.05 ...

Table 1 Mechanical prope...

Material Young’s modulus (MPa) Poisson ratio Artificial cancellous bone 628 0.3 Artificial cortical bone 1,373 ...

About this article : A biomechanical investigation...

Omori, M., Sato, Y., Kitagawa, N. et al. A biomechanical investigation of mandibular molar implants: reproducibility and validity of a finite element analysis model. Int J Implant Dent 1, 10 (2015). https://doi.org/10.1186/s40729-015-0011-5 Download citation Received: 07 January 2015 Accepted: 24 March 2015 Published: 28 April 2015 DOI: https://doi.org/10.1186/s40729-015-...

Rights and permissions : A biomechanical investiga...

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0), which permits use, duplication, adaptation, distribution, and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and in...

Additional information : A biomechanical investiga...

Miyuki Omori, Yuji Sato, Noboru Kitagawa, Yuta Shimura and Manabu Ito declare that they have no competing interests. MO drafted the manuscript. YS contributed advice regarding the manuscript. All authors have read and approved the final manuscript.

Author information : A biomechanical investigation...

Department of Geriatric Dentistry, Showa University, School of Dentistry, 2-1-1 Kitasenzoku, Ota-ku, Tokyo, 145-8515, Japan Miyuki Omori, Yuji Sato, Noboru Kitagawa, Yuta Shimura & Manabu Ito You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar You can also...

Acknowledgements : A biomechanical investigation o...

The authors would like to express their deep appreciation to the teaching staff of the Geriatric Dentistry course at Showa University Dental Hospital for their help and cooperation. This study was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology (Showa University Grant-in-Aid for Scientific Research (C)) (Grant Number 2546...

References : A biomechanical investigation of mand...

Tada S, Stegaroiu R, Kitamura E, Miyakawa O, Kusakari H. Influence of implant design and bone quality on stress/strain distribution in bone around implants: a 3-dimensional finite element analysis. Int J Oral Maxillofac Implants. 2003;18:357–68. Sevimay M, Turhan F, Kilicarslan MA, Eskitascioglu G. Three-dimensional finite element analysis of the effect of different bone quality on stress distr...

References : A biomechanical investigation of mand...

Matsunaga S, Ide Y. Morphological characteristics of peri-implant trabecular bone using μ-CT and its mechanical evaluation. BONE. 2009;23:289–92 [in Japanese]. Yokoyama M. Modeling techniques and stress analysis in finite element methods. Tokyo: Yokendo; 2007. p. 1–22 [in Japanese]. Sato Y, Shindoi N, Hosokawa R, Tsuga K, Akagawa Y. A biomechanical effect of wide implant placement and offse...

References : A biomechanical investigation of mand...

Morita Y, Qian L, Todo M, Matsushita Y, Arakawa K, Koyano K. Stress and strain distribution analyses of porcine mandibular periodontium by experimental mechanics and finite element analysis. Jpn J Clin Biomech. 2009;30:7–13 [in Japanese]. Taira S. Modern material mechanics. Tokyo: Ohmsha; 2011. p. 235–8 [in Japanese]. Morita Y. Experimental study on displacement and strain distributions arou...

References : A biomechanical investigation of mand...

Frost HM. Wolff’s Law and bone’s structural adaptations to mechanical usage: an overview for clinicians. Angle Orthod. 1994;64:175–88. Duyck J, Rønold HJ, Van Oosterwyck H, Naert I, Vander Sloten J, Ellingsen JE. The influence of static and dynamic loading on marginal bone reactions around osseointegrated implants: an animal experimental study. Clin Oral Implants Res. 2001;12:207–18. Qu...

Abbreviations : A biomechanical investigation of m...

finite element analysis computed tomography coefficient of variation computer-aided design/computer-aided manufacturing analysis of variance

Conclusions : A biomechanical investigation of man...

With the objective of verifying the reproducibility and validity of three-dimensional finite element models, we fabricated finite element models and multiple models in which implants were embedded in artificial mandibles and compared implant displacements under various loading conditions; the results obtained produced the following conclusions: The CVs as calculated from the amount of displacemen...

Discussion : A biomechanical investigation of mand...

The equivalent stress values of the contact model were higher at the implant neck than the tip, and the stress generation range was also broader. However, in the fixation model, the implant neck and tip had substantially equivalent values and the stress generation range was also narrower than that of the contact model. This shows that under immediate loading conditions, there is a high likelihood ...

Discussion : A biomechanical investigation of mand...

It has been reported that when micromovement of an implant occurs, an ingrowth of soft tissue occurs after the implant is embedded; therefore, it is difficult to achieve osseointegration [32-34]. Brunski et al. [35] reported that when immediate loading or early loading is carried out, micromovements of the implant should be controlled to 100 μm or less and excessive movement of the implant not o...

Discussion : A biomechanical investigation of mand...

In the experimental and contact models, the absolute values of displacement under loading were different, but aspects of the displacement under loading conditions caused by differences in the loading points were similar and showed similar tendencies. The correlation coefficient of the two was 0.925, representing a significant and strong correlation (p 

Discussion : A biomechanical investigation of mand...

In the experimental model, an implant cavity 3.0 mm in diameter was formed prior to embedding an implant 3.75 mm in diameter. In theory, the threads were completely mechanically fitted to the artificial mandibular bone. It does not osseointegrate, but does represent the circumstances of immediate loading in a state of full contact with the bone. The contact model reproduced the state of contact ...

Discussion : A biomechanical investigation of mand...

When a three-dimensional FEA is used to analyze the mechanics of peri-implant bone, it is ideal to construct an FEA model that approximates the material properties and structures of an actual mandible. Moreover, the results should be compared with the behavior of an implant in an actual mandible. However, in an actual oral cavity, individual differences exist resulting from bone morphology and phy...

Results : A biomechanical investigation of mandibu...

Central loading resulted in the lowest equivalent stress value, while buccal and lingual loading showed substantially similar values (Figure 12b). In the bone surrounding the implant tip, the loading point was a significant factor for the equivalent stress value (p 

Results : A biomechanical investigation of mandibu...

At all three loading sites, no. 36 had the greatest displacement; the more mesial the implant, the less the displacement, and the distal portions showed a sinking displacement (Figure 10). Central loading resulted in the least displacement; buccal and lingual loading showed substantially similar displacements. Compared with the contact model, the fixation model demonstrated less displacement, but...

Results : A biomechanical investigation of mandibu...

Figure 6 and Table 2 show the results for implant displacement under 100 N of vertical loading at each loading point and in each model. The implant displacement under loading conditions in the experimental model and the two FEA models showed a tendency to exhibit the smallest values under central loading; substantially similar values were exhibited in buccal and lingual loading. Buccal loading...

Methods : A biomechanical investigation of mandibu...

Regarding displacement under loading, a one-way analysis of variance (ANOVA) was used to investigate statistically significant differences between the loading sites. A three-way ANOVA was used to investigate statistically significant differences in three-dimensional implant displacements under loading conditions. The assessment site, dental formula, and loading point were used as intra-subject par...

Methods : A biomechanical investigation of mandibu...

Implant displacement measurements under loading conditions were measured using an Instron-type universal testing machine (Instron‐5500R®, Instron Japan, Kanagawa, Japan) for the experimental model. The experimental models were placed on the worktable of an Instron-type universal testing machine, and compression tests were performed using a conical jig. A vertical load was applied at a rate of 0...

Methods : A biomechanical investigation of mandibu...

The experimental models were fixed in a micro-CT scanner (inspeXio SMX-90CT, SHIMADZU, Kyoto, Japan) and scanned under the following imaging conditions: tube voltage, 90 kV; tube current, 109 nA; and slice thickness, 100 μm. FEA software (Mechanical Finder®, Research Center of Computational Mechanics, Tokyo, Japan) was used to construct three-dimensional FEA models from the resulting computed...

Methods : A biomechanical investigation of mandibu...

An artificial mandibular bone (P9-X.1135, Nissin Dental Products, Kyoto, Japan) with free-end edentulism of the left mandibular first premolar (no. 34), second premolar (no. 35), and first molar (no. 36) was used (Figure 1). The model is composed of a two-layer structure of artificial cortical bone (urethane resin) and artificial cancellous bone (urethane resin foam). Using the anatomical crown ...

Background : A biomechanical investigation of mand...

With the purpose of verifying the reproducibility and validity of a three-dimensional finite element model, the displacements of implants embedded in an experimental model and in three-dimensional FEA models constructed from the experimental model were compared under various loading conditions.

Background : A biomechanical investigation of mand...

Bone remodeling to maintain osseointegration between bone and implant is absolutely essential to ensure favorable results and long-term stability in implant treatment [1,2]. Bone remodeling requires that various stresses generated around the bone caused by the occlusal load applied to the implant be within an appropriate range. Concentrations of stress at the bone-implant interface, which are caus...

Abstract : A biomechanical investigation of mandib...

Three-dimensional finite element analysis (FEA) is effective in analyzing stress distributions around dental implants. However, FEA of living tissue involves many conditions, and the structures and behaviors are complex; thus, it is difficult to ensure the validity of the results. To verify reproducibility and validity, we embedded implants in experimental models and constructed FEA models; implan...

Fig. 15. Load supporting area in the superstructur...

Fig. 15. Load supporting area in the superstructures Fig. 15. Load supporting area in the superstructures

Fig. 14. The distribution of equivalent stress aro...

Fig. 14. The distribution of equivalent stress around the no. 36 implant in the finite element analysis (FEA) models Fig. 14. The distribution of equivalent stress around the no. 36 implant in the finite element analysis (FEA) models

Fig. 13. The distribution of equivalent stress aro...

Fig. 13. The distribution of equivalent stress around the peri-implant bone in the finite element analysis (FEA) models Fig. 13. The distribution of equivalent stress around the peri-implant bone in the finite element analysis (FEA) models

Fig. 12. The strain around the no. 36 implant in t...

Fig. 12. The strain around the no. 36 implant in the finite element analysis (FEA) models Fig. 12. The strain around the no. 36 implant in the finite element analysis (FEA) models

Fig. 11. The strain around the no. 36 implant in t...

Fig. 11. The strain around the no. 36 implant in the experimental models Fig. 11. The strain around the no. 36 implant in the experimental models

Fig. 10. The displacement of the three implants : ...

Fig. 10. The displacement of the three implants Fig. 10. The displacement of the three implants

Fig. 9. The displacement of the implants under loa...

Fig. 9. The displacement of the implants under loading in finite element analysis (FEA) models Fig. 9. The displacement of the implants under loading in finite element analysis (FEA) models

Fig. 8. The displacement of the implants under loa...

Fig. 8. The displacement of the implants under loading in experimental models Fig. 8. The displacement of the implants under loading in experimental models

Fig. 7. A finite element analysis (FEA) model. (a)...

Fig. 7. A finite element analysis (FEA) model. (a) Buccal load, (b) central load, and (c) lingual load Fig. 7. A finite element analysis (FEA) model. (a) Buccal load, (b) central load, and (c) lingual load

Fig. 6. Loading test in the experimental model : B...

Fig. 6. Loading test in the experimental model Fig. 6. Loading test in the experimental model

Fig. 5. Application of strain gauges : Biomechanic...

Fig. 5. Application of strain gauges Fig. 5. Application of strain gauges

Fig. 4. Experimental model. (a) Buccal load, (b) c...

Fig. 4. Experimental model. (a) Buccal load, (b) central load, and (c) lingual load Fig. 4. Experimental model. (a) Buccal load, (b) central load, and (c) lingual load

Fig. 3. Three different models with different plac...

Fig. 3. Three different models with different placements Fig. 3. Three different models with different placements

Table 9 Tukey’s test for strain L in the FEA mod...

Models Mean difference P value Straight B-offset −58.94 ...

Table 8 Tukey’s test for strain B in the FEA mod...

Models Mean difference P value Straight B-offset −402.94 ...

Table 7 Means and standard deviations (SD) of stra...

Models Loading Strain (με) Strain M Strain B Strain D ...

Table 6 Tukey’s test for strain L in the experim...

Models Mean difference P value Straight B-offset −25.14 ...

Table 5 Tukey’s test for strain B in the experim...

Models Mean difference P value Straight B-offset 1524.82 ...

Table 4 Means and standard deviations (SD) of stra...

Models Loading Strain (με) Strain M Strain B Strain D ...

Table 3 Means and standard deviations (SD) of disp...

Models Displacement (μm) Buccal loading Central loading Lingual loading Buccal offse...

Table 2 Means and standard deviations (SD) of disp...

Models Displacement (μm) Buccal loading Central loading Lingual loading Buccal offse...

Table 1 Mechanical properties of materials used in...

Material Young’s modulus (MPa) Poisson’s ratio Artificial cancellous bone 6.29 0.3 Artificial cortical bone 13.73 0.3 Implant and superstructure 108,000 0.3   Table 1 Mechanical properties of materials used in the FEA models

About this article : Biomechanical effects of offs...

Shimura, Y., Sato, Y., Kitagawa, N. et al. Biomechanical effects of offset placement of dental implants in the edentulous posterior mandible. Int J Implant Dent 2, 17 (2016). https://doi.org/10.1186/s40729-016-0050-6 Download citation Received: 18 January 2016 Accepted: 13 June 2016 Published: 17 June 2016 DOI: https://doi.org/10.1186/s40729-016-0050-6

Rights and permissions : Biomechanical effects of ...

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were m...

Additional information : Biomechanical effects of ...

Yuta Shimura, Yuji Sato, Noboru Kitagawa, and Miyuki Omori declare that they have no competing interests. YS drafted the manuscript. YS, NK, and MO contributed advice for the manuscript. All authors read and approved the final manuscript.

Author information : Biomechanical effects of offs...

Department of Geriatric Dentistry, Showa University, 2-1-1 Kitasenzoku, Ota-ku, Tokyo, 145-8515, Japan Yuta Shimura, Yuji Sato, Noboru Kitagawa & Miyuki Omori You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar You can also search for this author in ...

Acknowledgements : Biomechanical effects of offset...

We are sincerely grateful for the assistance we received from the teaching staff of the Geriatric Dentistry course at Showa University Dental Hospital; Professor Takashi Miyazaki and the late Akihiro Fujishima of the Department of Conservative Dentistry, Division of Oral Biomaterials and Engineering; Professor Masanori Nakamura of the Department of Oral Anatomy and Developmental Biology; and Profe...

References : Biomechanical effects of offset place...

Yoshino A. Effects of ratio of superstructure length to fixture length on the strain of the bone surfaces surrounding the implant. J Jpn Soc Oral Implantol. 2001;14:398–413. in Japanese. Rangert B, Jemt T, Jörneus L. Forces and moments on Branemark implants. Int J Oral Maxillofac Implants. 1989;4:241–7. Sato Y. Discussion of offset arrangement in implants. Quintessence Dent Implantol. 2000;...

References : Biomechanical effects of offset place...

Nishioka RS, de Vasconcellos LG, de Melo Nishioka LN. External hexagon and internal hexagon in straight and offset implant placement: strain gauge analysis. Implant Dent. 2009;18:512–20. Nishioka RS, de Vasconcellos LG, de Melo Nishioka GN. Comparative strain gauge analysis of external and internal hexagon, Morse taper, and influence of straight and offset implant configuration. Implant Dent. 2...

References : Biomechanical effects of offset place...

Frost HM. Wolff’s Law and bone’s structural adaptations to mechanical usage: an overview for clinicians. Angle Orthod. 1994;64:175–88. Duyck J, Rønold HJ, Van Oosterwyck H, Naert I, Vander Sloten J, Ellingsen JE. The influence of static and dynamic loading on marginal bone reactions around osseointegrated implants: an animal experimental study. Clin Oral Implants Res. 2001;12:207–18. Qu...

Conclusions : Biomechanical effects of offset plac...

In the present study, which aimed to verify the biomechanical effects of offset placement on peri-implant bone, we created multiple finite element models and models where implants were actually placed. We compared the compressed displacement as well as the strain and stress distribution in the peri-implant bone between both kinds of models, and the results can be summarized as follows: Central lo...

Discussion : Biomechanical effects of offset place...

Concentration of stress in the loading-side peri-implant bone was observed in all placements and for both the experimental and the FEA models. Considerable stress was also found to be concentrated in the no. 36 peri-implant bone in buccal loading with buccal offset and lingual loading with lingual offset. Similar to the strain results, stress was observed in a large range under conditions where th...

Discussion : Biomechanical effects of offset place...

Similar trends were observed in the direction and magnitude of displacement between placements. Buccal loading exhibited considerable motion towards the buccal rotation/tilting of the implant bodies, and lingual loading exhibited little motion towards lingual displacement. This corresponds to the fact that there was more compressed displacement during buccal loading than during lingual loading. I...

Discussion : Biomechanical effects of offset place...

Moreover, considering the possibility of error while using an implant placement guide, we created many FEA models for each placement to compare the accuracy between the same placement models used with different FEA models. Most studies verifying the usefulness of offset placement used a single technique for analysis [8–19]. Therefore, the results regarding the usefulness of offset placement var...

Discussion : Biomechanical effects of offset place...

Reported studies verifying the effects of offset placement include ones where implant bodies were embedded in rectangular experimental models [11–14], ones where rectangular bone models were constructed with FEA models [15, 16], and ones where FEA models were constructed from CT data on human mandibles [17, 18]. The artificial mandible models used in the present study were type II in the Lekholm...

Results : Biomechanical effects of offset placemen...

Figure 11 and Table 4 show the strain, by loading site, in the implant part corresponding to the first molar in the experimental models during the application of a 100-N vertical load. Considerable compressive strain was observed with the load-side strain gauges in all placements, and similar trends were observed between placements. As much as about 4500 με of compressive strain was observed...

Results : Biomechanical effects of offset placemen...

Figures 8 and 9 and Tables 2 and 3 show the results for the compressed displacement of the implants, by loading site, during the application of a 100-N vertical load in each of the models. In all placements, the compressed displacement in the experimental models and FEA models was greatest with buccal loading and smallest with central loading at the three loading points. For both the experiment...

Methods : Biomechanical effects of offset placemen...

The places on the experimental models where the strain gauges were applied were represented as coordinate points on the FEA models, and the strain in the FEA models was calculated by dividing the change in length between before and after loading by the length of the strain gauges. An equivalent stress occurring in the peri-implant bone during loading was observed and assessed in a buccolingual cr...

Methods : Biomechanical effects of offset placemen...

Implant displacement under loading conditions was measured using an Instron-type universal testing machine (Instron-5500R®, Instron Japan, Kanagawa, Japan) for the experimental model. The experimental models were placed on the worktable of an Instron-type universal testing machine, and compression tests were performed using a conical jig. A vertical load was applied at a rate of 0.5 mm/s on the ...

Methods : Biomechanical effects of offset placemen...

Four two-wire strain gauges (KFR-02N-120-C1-11, Kyowa Electronic Instruments, Tokyo, Japan) were applied to the no. 36 peri-implant bone surface [21]. The surface of the measurement site was polished with no. 320 sandpaper and then wiped clean with acetone, following which they were adhered with a special adhesive (CC-33A, Kyowa Electronic Instruments, Tokyo, Japan). The strain gauges were applied...

Methods : Biomechanical effects of offset placemen...

An artificial mandibular bone (P9-X.1135, Nissin Dental Products, Kyoto, Japan) with free-end edentulism of the left mandibular first premolar (no. 34), second premolar (no. 35), and first molar (no. 36) was used (Fig. 1). The model was composed of a two-layer structure of artificial cortical bone (urethane resin) and artificial cancellous bone (urethane resin foam). Using the anatomical crown w...

Background : Biomechanical effects of offset place...

Bone remodeling to maintain osseointegration between the bone and implant is absolutely essential to ensure favorable results and long-term stability in implant treatment [1, 2]. Bone remodeling requires that various stresses generated around the bone caused by the occlusal load applied to the implant be within an appropriate range. The concentration of stress at the bone-implant interface, caused...

Abstract : Biomechanical effects of offset placeme...

Offset placement may not necessarily be more biomechanically effective than straight placement in edentulous posterior mandibles.

Abstract : Biomechanical effects of offset placeme...

Proper implant placement is very important for long-term implant stability. Recently, numerous biomechanical studies have been conducted to clarify the relationship between implant placement and peri-implant stress. The placement of multiple implants in the edentulous posterior mandible has been studied by geometric analysis, three-dimensional finite element analysis (FEA), model experimentation, ...

Table 9 Tukey’s test for strain L in the FEA mod...

Models Mean difference P value Straight B-offset −58.94 0.855 Straight L-offset 270.67 0.061 B-offset L-offset 329.61 0.020

Table 8 Tukey’s test for strain B in the FEA mod...

Models Mean difference P value Straight B-offset −402.94 0.007 Straight L-offset −323.79 0.029 B-offset L-offset 79.16 0.772

Table 7 Means and standard deviations (SD) of stra...

Table 7 Means and standard deviations (SD) of strain around the no. 36 implant (με) in the finite element analysis (FEA) models Models Loading Strain (με) Strain M Strain B Strain D Strain L Buccal offset Buccal loading −222.34 ± 158.56 −934.84 ± 76.82 252.11 ± 103.72 −98.32 95.94 Central loading −336.26 ± 94.27 −477.17 ±...

Table 6 Tukey’s test for strain L in the experim...

Table 6 Tukey’s test for strain L in the experimental models Models Mean difference P value Straight B-offset −25.14 0.999 Straight L-offset 168.04 0.948 B-offset L-offset 193.18 0.932

Table 5 Tukey’s test for strain B in the experim...

Table 5 Tukey’s test for strain B in the experimental models Models Mean difference P value Straight B-offset 1524.82 0.044 Straight L-offset −503.40 0.670 B-offset L-offset −2028.22 0.007

Table 4 Means and standard deviations (SD) of stra...

Table 4 Means and standard deviations (SD) of strain around the no. 36 implant (με) in the experimental models Models Loading Strain (με) Strain M Strain B Strain D Strain L Buccal offset Buccal loading −599.33 ± 595.46 −4507.35 ± 1192.62 1164.77 ± 169.94 −148.09 ± 174.19 Central loading −697.29 ± 651.92 −2526.69 ± 5...

Table 3 Means and standard deviations (SD) of disp...

Models Displacement (μm) Buccal loading Central loading Lingual loading Buccal offset 72.24 ± 1.43 28.24 ± 1.86 28.02 ± 1.41 Straight 68.49 ± 5.24 31.43 ± 1.23 40.18 ± 1.29 Lingual offset 49.63 ± 2.03 26.39 ± 0.37 38.44 ± 1.46

Table 2 Means and standard deviations (SD) of disp...

Table 2 Means and standard deviations (SD) of displacement of the implants (μm) under loading in experimental models Models Displacement (μm) Buccal loading Central loading Lingual loading Buccal offset 54.60 ± 8.53 37.39 ± 5.53 40.22 ± 4.24 Straight 80.66 ± 7.47 52.92 ± 1.07 63.03 ± 3.69 Lingual offset 53.11 ± 4.35 40....

Table 1 Mechanical properties of materials used in...

Table 1 Mechanical properties of materials used in the FEA models Material Young’s modulus (MPa) Poisson’s ratio Artificial cancellous bone 6.29 0.3 Artificial cortical bone 13.73 0.3 Implant and superstructure 108,000 0.3

Figure 15. Load supporting area in the superstruct...

  Figure 15. Load supporting area in the superstructures

Figure 14. The distribution of equivalent stress a...

  Figure 14. The distribution of equivalent stress around the no. 36 implant in the finite element analysis (FEA) models

Figure 13. The distribution of equivalent stress a...

  Figure 13. The distribution of equivalent stress around the peri-implant bone in the finite element analysis (FEA) models

Figure 12. The strain around the no. 36 implant

  Figure 12. The strain around the no. 36 implant in the finite element analysis (FEA) models

Figure 11. The strain around the no. 36 implant in...

Figure 11. The strain around the no. 36 implant in the experimental models

Figure 9. The displacement of the implants under l...

  Figure 9. The displacement of the implants under loading in finite element analysis (FEA) models

Figure 8. The displacement of the implants under l...

  Figure 8. The displacement of the implants under loading in experimental models  

Figure 7. A finite element analysis (FEA) model

Figure 7. A finite element analysis (FEA) model. (a) Buccal load, (b) central load, and (c) lingual load Figure 7. A finite element analysis (FEA) model. (a) Buccal load, (b) central load, and (c) lingual load

Figure 6. Loading test in the experimental model

  Figure 6. Loading test in the experimental model

Figure 5. Application of strain gauges

Figure 5. Application of strain gauges

Figure 4. Experimental model. (a) Buccal load, (b)...

  Figure 4. Experimental model. (a) Buccal load, (b) central load, and (c) lingual load

Figure 3. Three different models with different pl...

Figure 3. Three different models with different placements

Figure 2. Three implants were embedded in an artif...

Figure 2. Three implants were embedded in an artificial mandible

Figure 1. An artificial mandible

Figure 1. An artificial mandible

References : Biomechanical effects of offset place...

References Frost HM. Wolff’s Law and bone’s structural adaptations to mechanical usage: an overview for clinicians. Angle Orthod. 1994;64:175–88. Duyck J, Rønold HJ, Van Oosterwyck H, Naert I, Vander Sloten J, Ellingsen JE. The influence of static and dynamic loading on marginal bone reactions around osseointegrated implants: an animal experimental study. Clin Oral Implants Res. 200...

Discussion : Biomechanical effects of offset place...

In addition, there was not a significantly less strain site by offset placement. Anitua et al. have reported that offset placement did not affect marginal bone loss around the implant in the oral cavity of the living body. Overloading of the peri-implant bone has been reported to result in bone resorption, and the concentration of considerable stress in the load-side peri-implant bone observ...

Discussion : Biomechanical effects of offset place...

Thus, compressed displacement exhibited the same trend in the experimental models and FEA models. The results of both models may be reliable. When the effects of offset placement are considered, there is the concept of the load-supporting area (Fig. 15) put forth by Sato. The load-supporting area is the area surrounded by the lines connecting the implant peripheries, and if a loading point falls w...

Discussion : Biomechanical effects of offset place...

In previous studies verifying the usefulness of offset placement, one set of FEA models was created and analyzed by changing the conditions or settings. Few studies used different FEA models with the same placement models. In the present study, we carried out the same experiments with both the models to verify the validity of each analysis. Moreover, considering the possibility of error while usi...

Discussion : Biomechanical effects of offset place...

Strain in the FEA models also exhibited considerable compressive strain on the loading side, similar to the experimental models. In terms of quantitative data for comparison with the experimental models, the length of the places where the strain gauges were applied was measured on the FEA models and the strain was calculated from the length before and after loading and compared with the expe...

Discussion : Biomechanical effects of offset place...

Discussion Experimental models Reported studies verifying the effects of offset placement include ones where implant bodies were embedded in rectangular experimental models, ones where rectangular bone models were constructed with FEA models, and ones where FEA models were constructed from CT data on human mandibles. The artificial mandible models used in the present study were type II in the ...

Results : Biomechanical effects of offset placemen...

  Strain on the peri-implant bone Strain in the experimental models Figure 11 and Table 4 show the strain, by loading site, in the implant part corresponding to the first molar in the experimental models during the application of a 100-N vertical load. Considerable compressive strain was observed with the load-side strain gauges in all placements, and similar trends were observed between pl...

Methods : Biomechanical effects of offset placemen...

A strain gauge (2630-100, Instron Japan, Kanagawa, Japan) was attached between the worktable and jig, and the change in the distance between the worktable and jig was measured under the assumption that it would be the same as the implant displacements under loading conditions (Fig. 6). Measurements were taken five times at each loading site, and the mean of the five measurements was considered the...

Methods : Biomechanical effects of offset placemen...

FEA software (Mechanical Finder®, Research Center of Computational Mechanics, Tokyo, Japan) was used to construct three-dimensional FEA models from the resulting CT data. The mesh was constructed of tetrahedral elements, and the total numbers of nodes and elements were approximately 260,000 and 1,400,000, respectively. FEA models were prepared with appropriate physical properties (Table 1) determ...

Methods : Biomechanical effects of offset placemen...

Preparation of the superstructure Using the anatomical crown width as a reference, it was determined that the occlusal surface view of the superstructure would be trapezoidal with a 7-mm buccolingual width in the mesial first premolar section, a 10-mm buccolingual width in the distal first molar section, and a 26-mm mesiodistal width (Fig. 4). The vertical dimension was 8 mm; the upper 4 mm was t...

Results : Biomechanical effects of offset placemen...

Compressed displacement Figures 8 and 9 and Tables 2 and 3 show the results for the compressed displacement of the implants, by loading site, during the application of a 100-N vertical load in each of the models. In all placements, the compressed displacement in the experimental models and FEA models was greatest with buccal loading and smallest with central loading at the three loading points....

Methods : Biomechanical effects of offset placemen...

Methods Fabrication of the experimental model Artificial mandibular bone An artificial mandibular bone (P9-X.1135, Nissin Dental Products, Kyoto, Japan) with free-end edentulism of the left mandibular first premolar (no. 34), second premolar (no. 35), and first molar (no. 36) was used (Fig. 1). The model was composed of a two-layer structure of artificial cortical bone (urethane resin) and ar...

Background : Biomechanical effects of offset place...

Background Bone remodeling to maintain osseointegration between the bone and implant is absolutely essential to ensure favorable results and long-term stability in implant treatment. Bone remodeling requires that various stresses generated around the bone caused by the occlusal load applied to the implant be within an appropriate range. The concentration of stress at the bone-implant interface,...

Biomechanical effects of offset placement of denta...

Biomechanical effects of offset placement of dental implants in the edentulous posterior mandible Abstract Background Proper implant placement is very important for long-term implant stability. Recently, numerous biomechanical studies have been conducted to clarify the relationship between implant placement and peri-implant stress. The placement of multiple implants in the edentulous posterio...