Fig. 7. The box plot shows the distribution of age between the sex groups
Fig. 7. The box plot shows the distribution of age between the sex groups
Fig. 6. Pie chart shows the distribution of loaded implants prosthetic restorations
Fig. 6. Pie chart shows the distribution of loaded implants prosthetic restorations
Fig. 5. Pie charts shows the distribution of the demographic datas of the patients
Fig. 5. Pie charts shows the distribution of the demographic datas of the patients
Fig. 4. The crown-implant ratio measurement showing a the length of the crown (red line) and b the length of the implant (red line)
Fig. 4. The crown-implant ratio measurement showing a the length of the crown (red line) and b the length of the implant (red line)
Fig. 3. Fractal analysis stages. a Selected region of interest (ROI). b Cropped and duplicated version of ROI. c Addition of Gaussian filter. d Subtraction. e Addition of 128 pixels. f Binarized version. g Eroded version. h Dilated version. i Inverted version j Skeletonization
Fig. 3. Fractal analysis stages. a Selected region of interest (ROI). b Cropped and duplicated version of ROI. c Addi...
Fig. 2. Region of interests (ROIs) were selected arbitrarily in a preoperative radiographic image and b a follow-up radiographic image
Fig. 2. Region of interests (ROIs) were selected arbitrarily in a preoperative radiographic image and b a follow-up radiographic image
Fig. 1. Fractal dimension values measured from the same area of interest on each panoramic radiograph over five different time intervals are shown in the figure. FD0, fractal dimension 0 (preoperative); FD1, fractal dimension 1 (0–1 months of follow-up); FD2, fractal dimension 2 (1–3 months of follow-up); FD3, fractal dimension 3 (6–12 months of follow-up); FD4, fractal dimension 4 ...
nMeanStandard deviationMinimumMaximumFD01301.2430.1520.7501.560FD11301.1130.2240.4051.510FD21301.1160.1960.4101.510FD3671.0920.2160.4301.500FD4671.0810.2470.4301.500Table 2 Mean fractal dimension (FD) values before and after implant insertion
Failure (n)Success (n)P valuePowerEffect sizeSexWomen3870.0240.680.21Men634FD190.82 ± 0.28 (mean)0.45 (min)–1.26 (max)1211.13 ± 0.25 (mean)0.41 (min)–1.51 (max)< 0.0010.991.45FD290.97 ± 0.24 (mean)0.61 (min)–1.36 (max)1211.13 ± 0.19 (mean)0.41 (min)–1.51 (max)0.0230.990.79Crown-implant Ratio26.51 ± 3.89 (mean)3.77 (min)–9.27 (max)654.61 ± 1.58 (mean)2.57 min)–10.67 (max)0.101...
Kış, H.C., Güleryüz Gürbulak, A. Evaluation of the peri-implant bone trabecular microstructure changes in short implants with fractal analysis. Int J Implant Dent 6, 13 (2020). https://doi.org/10.1186/s40729-020-00209-7
Download citation
Received: 12 September 2019
Accepted: 12 March 2020
Published: 01 April 2020
DOI: https://doi.org/10.1186/s40729-020-00209-7
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, 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 licence, and indicate if changes were made. The images or other third party material...
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
Hatice Cansu Kış and Ayşegül Güleryüz Gür...
Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Nuh Naci Yazgan University, Kayseri, Turkey
Hatice Cansu Kış
Department of Prosthetic Dentistry, Faculty of Dentistry, Erciyes University, Kayseri, Turkey
Ayşegül Güleryüz Gürbulak
You can also search for this author in PubMed Google Scholar
You can also search for this author in PubMed Google Scholar
AGG collecte...
The work was supported by the Department of Oral & Maxillofacial Radiology, Nuh Naci Yazgan University in Kayseri, Turkey.
We would like to thank Editage (www.editage.com) for English language editing.
Mu T-J, Lee D-W, Park K-H, Moon I-S. Changes in the fractal dimension of peri-implant trabecular bone after loading: a retrospective study. Journal of periodontal & implant science. 2013;43(5):209–14.
Zeytinoğlu M, İlhan B, Dündar N, Boyacioğlu H. Fractal analysis for the assessment of trabecular peri-implant alveolar bone using panoramic radiographs. Clinical oral investigations. 2015;19(2...
Mandelbrot BB. The fractal geometry of nature: WH freeman New York; 1983.
Sánchez I, Uzcátegui G. Fractals in dentistry. Journal of dentistry. 2011;39(4):273–92.
Boutroy S, Bouxsein ML, Munoz F, Delmas PD. In vivo assessment of trabecular bone microarchitecture by high-resolution peripheral quantitative computed tomography. The Journal of Clinical Endocrinology & Metabolism. 2005;90(12):6508...
Dental panoramic radiographs
Fractal dimension 0 (preoperative)
Fractal dimension 1 (0–1 months of follow-up)
Fractal dimension 2 (1–3 months of follow-up)
Fractal dimension 3 (6–12 months of follow-up)
Fractal dimension 4 (12 + months of follow-up)
Cone beam computed tomography
Region of interest
Fractal analysis is a useful method to measure the trabecular microstructure of bone in nonstandardized dental radiographs. The present study has a low power to reject the null hypothesis because of the low number of cases of failed implants. Therefore, further studies with a large sample size are warranted. Assessing a series of studies can provide certain cut-off values; this can enable to routi...
Fractal analysis of bone microstructure on dental radiographs may be useful for diagnostic applications; however, the histological microstructures of the bone cannot be visualized by any clinical imaging modality. Corpas et al. [12] stated that minor changes in bone occurring over a short-term period can be followed up with digital intraoral radiography; however, the results of radiographic fracta...
This study aimed to evaluate the microstructural changes in the peri-implant bone in patients with short implants in terms of the implant survival status by using fractal analysis measurements.
In this study, a significant difference was found in the FD1 and FD2 values between the implant survival groups, and the mean FD1 and FD2 values of the success group were significantly higher than those of...
Descriptive statistics were performed. The data were not normally distributed (p < 0.05). The intra-observer correlation coefficients of repeated measurements were 0.927, 0.889, 0.913, 0.988, 0.961, and 0.936 for FD0 (fractal dimension), FD1, FD2, FD3, FD4, and crown-implant ratio, respectively. Descriptive data are shown in Figs. 5, 6, and 7. A significant difference was found for sex between the...
The crown-implant ratio was measured using the ImageJ version 1.38 software measuring tool in conjunction with a magnification tool. Each implant was measured from its bottom to the crown base and then from the crown base to its highest point (Fig. 4).
All measurements were performed by a dento-maxillofacial radiologist who was blinded to patient information. To evaluate the intra-observer correl...
This retrospective study was conducted in the dental clinic of Oral and Maxillofacial Radiology department and was approved by the local ethics committee (2013/203). The participants had approached the Prosthodontics Clinic between 2012 and 2019 for partial or complete tooth complaints. Among the data of 116 patients reviewed, panoramic radiographs of 67 patients were examined and included in this...
The quality of bone tissue at the site of implantation can be determined preoperatively with high accuracy, and changes in the trabecular structure, which is vital for the primary and secondary stability of the implant, can be observed during the follow-up after implantation.
Previous studies have evaluated fractal analysis of peri-implant bone before and after loading. However, no study has exam...
Mandelbrot introduced fractals to describe his observation of shapes in nature, such as curves, surfaces, disconnected “dust,” and odd shapes. The word fractal originates from the Latin word “fractus,” which means broken. By using fractal mathematics, several studies have analyzed various fractal patterns in the human body. Fractal analysis is a mathematical method of describing complex sh...
This study aimed to evaluate the microstructural changes in the peri-implant bone in patients with short implants in terms of implant survival status by using fractal analysis measurements.
Dental panoramic radiographs (DPRs) of 67 patients were examined and included in this study. Fractal analysis and measurement of the crown-implant ratio were performed with ImageJ. The fractal analysis measure...
Fig. 7. The box plot shows the distribution of age between the sex groups
Fig. 7. The box plot shows the distribution of age between the sex groups
Fig. 6. Pie chart shows the distribution of loaded implants prosthetic restorations
Fig. 6. Pie chart shows the distribution of loaded implants prosthetic restorations
Fig. 5. Pie charts shows the distribution of the demographic datas of the patients
Fig. 5. Pie charts shows the distribution of the demographic datas of the patients
Fig. 4. The crown-implant ratio measurement showing a the length of the crown (red line) and b the length of the implant (red line)
Fig. 4. The crown-implant ratio measurement showing a the length of the crown (red line) and b the length of the implant (red line)
Fig. 3. Fractal analysis stages. a Selected region of interest (ROI). b Cropped and duplicated version of ROI. c Addition of Gaussian filter. d Subtraction. e Addition of 128 pixels. f Binarized version. g Eroded version. h Dilated version. i Inverted version j Skeletonization
Fig. 3. Fractal analysis stages. a Selected region of interest (ROI). b Cropped and duplicated version of ROI. c Addi...
Fig. 2. Region of interests (ROIs) were selected arbitrarily in a preoperative radiographic image and b a follow-up radiographic image
Fig. 2. Region of interests (ROIs) were selected arbitrarily in a preoperative radiographic image and b a follow-up radiographic image
Fig. 1. Fractal dimension values measured from the same area of interest on each panoramic radiograph over five different time intervals are shown in the figure. FD0, fractal dimension 0 (preoperative); FD1, fractal dimension 1 (0–1 months of follow-up); FD2, fractal dimension 2 (1–3 months of follow-up); FD3, fractal dimension 3 (6–12 months of follow-up); FD4, fractal dimension 4 ...
n
Mean
Standard deviation
Minimum
Maximum
FD0
130
1.243
0.152
0.750
1.560
FD1
130
1.113
0.224
0.405
1.510
FD2
130
1.116
0.196
0.410
1.510
FD3
67
1.092
0.216
0.430
1.500
FD4
67
1.081
0.247
0.430
1.500
Table 2 Mean fractal dimension (FD) values before and after implant insertion
Failure (n)Success (n)P valuePowerEffect sizeSexWomen3870.0240.680.21Men634FD190.82 ± 0.28 (mean)0.45 (min)–1.26 (max)1211.13 ± 0.25 (mean)0.41 (min)–1.51 (max)< 0.0010.991.45FD290.97 ± 0.24 (mean)0.61 (min)–1.36 (max)1211.13 ± 0.19 (mean)0.41 (min)–1.51 (max)0.0230.990.79Crown-implant Ratio26.51 ± 3.89 (mean)3.77 (min)–9.27 (max)654.61 ± 1.58 (mean)2.57 min)–10.67 (max)0.101...
Kış, H.C., Güleryüz Gürbulak, A. Evaluation of the peri-implant bone trabecular microstructure changes in short implants with fractal analysis. Int J Implant Dent 6, 13 (2020). https://doi.org/10.1186/s40729-020-00209-7
Download citation
Received: 12 September 2019
Accepted: 12 March 2020
Published: 01 April 2020
DOI: https://doi.org/10.1186/s40729-020-00209-7
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, 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 licence, and indicate if changes were made. The images or other third party material...
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
Hatice Cansu Kış and Ayşegül Güleryüz Gür...
Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Nuh Naci Yazgan University, Kayseri, Turkey
Hatice Cansu Kış
Department of Prosthetic Dentistry, Faculty of Dentistry, Erciyes University, Kayseri, Turkey
Ayşegül Güleryüz Gürbulak
You can also search for this author in PubMed Google Scholar
You can also search for this author in PubMed Google Scholar
AGG collecte...
The work was supported by the Department of Oral & Maxillofacial Radiology, Nuh Naci Yazgan University in Kayseri, Turkey.
We would like to thank Editage (www.editage.com) for English language editing.
Mu T-J, Lee D-W, Park K-H, Moon I-S. Changes in the fractal dimension of peri-implant trabecular bone after loading: a retrospective study. Journal of periodontal & implant science. 2013;43(5):209–14.
Zeytinoğlu M, İlhan B, Dündar N, Boyacioğlu H. Fractal analysis for the assessment of trabecular peri-implant alveolar bone using panoramic radiographs. Clinical oral investigations. 2015;19(2...
Mandelbrot BB. The fractal geometry of nature: WH freeman New York; 1983.
Sánchez I, Uzcátegui G. Fractals in dentistry. Journal of dentistry. 2011;39(4):273–92.
Boutroy S, Bouxsein ML, Munoz F, Delmas PD. In vivo assessment of trabecular bone microarchitecture by high-resolution peripheral quantitative computed tomography. The Journal of Clinical Endocrinology & Metabolism. 2005;90(12):6508...
Dental panoramic radiographs
Fractal dimension 0 (preoperative)
Fractal dimension 1 (0–1 months of follow-up)
Fractal dimension 2 (1–3 months of follow-up)
Fractal dimension 3 (6–12 months of follow-up)
Fractal dimension 4 (12 + months of follow-up)
Cone beam computed tomography
Region of interest
Fractal analysis is a useful method to measure the trabecular microstructure of bone in nonstandardized dental radiographs. The present study has a low power to reject the null hypothesis because of the low number of cases of failed implants. Therefore, further studies with a large sample size are warranted. Assessing a series of studies can provide certain cut-off values; this can enable to routi...
Fractal analysis of bone microstructure on dental radiographs may be useful for diagnostic applications; however, the histological microstructures of the bone cannot be visualized by any clinical imaging modality. Corpas et al. [12] stated that minor changes in bone occurring over a short-term period can be followed up with digital intraoral radiography; however, the results of radiographic fracta...
This study aimed to evaluate the microstructural changes in the peri-implant bone in patients with short implants in terms of the implant survival status by using fractal analysis measurements.
In this study, a significant difference was found in the FD1 and FD2 values between the implant survival groups, and the mean FD1 and FD2 values of the success group were significantly higher than those of...
Descriptive statistics were performed. The data were not normally distributed (p < 0.05). The intra-observer correlation coefficients of repeated measurements were 0.927, 0.889, 0.913, 0.988, 0.961, and 0.936 for FD0 (fractal dimension), FD1, FD2, FD3, FD4, and crown-implant ratio, respectively. Descriptive data are shown in Figs. 5, 6, and 7. A significant difference was found for sex between the...
The crown-implant ratio was measured using the ImageJ version 1.38 software measuring tool in conjunction with a magnification tool. Each implant was measured from its bottom to the crown base and then from the crown base to its highest point (Fig. 4).
All measurements were performed by a dento-maxillofacial radiologist who was blinded to patient information. To evaluate the intra-observer correl...
This retrospective study was conducted in the dental clinic of Oral and Maxillofacial Radiology department and was approved by the local ethics committee (2013/203). The participants had approached the Prosthodontics Clinic between 2012 and 2019 for partial or complete tooth complaints. Among the data of 116 patients reviewed, panoramic radiographs of 67 patients were examined and included in this...
The quality of bone tissue at the site of implantation can be determined preoperatively with high accuracy, and changes in the trabecular structure, which is vital for the primary and secondary stability of the implant, can be observed during the follow-up after implantation.
Previous studies have evaluated fractal analysis of peri-implant bone before and after loading. However, no study has exam...
Mandelbrot introduced fractals to describe his observation of shapes in nature, such as curves, surfaces, disconnected “dust,” and odd shapes. The word fractal originates from the Latin word “fractus,” which means broken. By using fractal mathematics, several studies have analyzed various fractal patterns in the human body. Fractal analysis is a mathematical method of describing complex sh...
This study aimed to evaluate the microstructural changes in the peri-implant bone in patients with short implants in terms of implant survival status by using fractal analysis measurements.
Dental panoramic radiographs (DPRs) of 67 patients were examined and included in this study. Fractal analysis and measurement of the crown-implant ratio were performed with ImageJ. The fractal analysis measure...
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 (MPa) around the first molar.
Figure 11. The distribution of equivalent stress (MPa) around the first molar.
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 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 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. (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 conditions.
Figure 6. Implant displacement under loading conditions.
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.
Figure 4. An experimental model loading test.
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 artificial mandible.
Figure 2. Three implants were embedded in an artificial mandible.
Figure 1. An artificial mandible.
Figure 1. An artificial mandible.
Model
Loading points
Buccal loading
Central loading
Lingual loading
Average
The neck of the implant
Contact model
No. 34
9.62
...
Source
Sum of squares
df
Mean squared
F
value
p
value
The neck of the implant
A: Boundary conditions
64.725
1
...
Source
Sum of squares
df
Mean squared
F
value
p
value
Contact model
A: Observed area
22.324
1
22.324
...
Source
Sum of squares
df
Mean squared
F
value
p
value
Contact model
A: Observed area
116.630
1
116.63...
Source
Sum of squares
df
Mean squared
F
value
p
value
Contact model
A: Observed area
16.346
1
16.346
...
Model
Loading
Average
Buccal loading
Central loading
Lingual loading
Experimental model
2.49
4.76
4.90
4.05
...
Material
Young’s modulus (MPa)
Poisson ratio
Artificial cancellous bone
628
0.3
Artificial cortical bone
1,373
...
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-...
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...
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.
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...
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...
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...
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...
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...
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...
finite element analysis
computed tomography
coefficient of variation
computer-aided design/computer-aided manufacturing
analysis of variance
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...
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 ...
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...
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
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 ...
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...
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
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...
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...
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...
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...
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...
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 ...
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.
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...
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 superstructures
Fig. 15. Load supporting area in the superstructures
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 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 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 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. 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 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) 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
Fig. 6. Loading test in the experimental model
Fig. 5. Application of strain gauges
Fig. 5. Application of strain gauges
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 placements
Fig. 3. Three different models with different placements
Models
Mean difference
P value
Straight
B-offset
−58.94
...
Models
Mean difference
P value
Straight
B-offset
−402.94
...
Models
Loading
Strain (με)
Strain M
Strain B
Strain D
...
Models
Mean difference
P value
Straight
B-offset
−25.14
...
Models
Mean difference
P value
Straight
B-offset
1524.82
...
Models
Loading
Strain (με)
Strain M
Strain B
Strain D
...
Models
Displacement (μm)
Buccal loading
Central loading
Lingual loading
Buccal offse...
Models
Displacement (μm)
Buccal loading
Central loading
Lingual loading
Buccal offse...
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
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
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...
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.
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
...
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...
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;...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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 ...
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...
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...
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...
Offset placement may not necessarily be more biomechanically effective than straight placement in edentulous posterior mandibles.
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, ...
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
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 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 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 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 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...
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 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 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 superstructures
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 around the peri-implant bone in the finite element analysis (FEA) models
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 the experimental models
Figure 9. The displacement of the implants under loading in finite element analysis (FEA) models
Figure 8. The displacement of the implants under loading in experimental models
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 5. Application of strain gauges
Figure 4. Experimental model. (a) Buccal load, (b) central load, and (c) lingual load
Figure 3. Three different models with different placements
Figure 2. Three implants were embedded in an artificial mandible
Figure 1. An artificial mandible
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...
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...
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...
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...
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
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 ...
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...
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...
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...
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...
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
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
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 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...
Figure 3. Comparison of standard and over-dimensioned protocol. The figure displayed shows the comparison between standard and over-dimensioned protocol. a Displays the measurements obtained by RFA. The unit is ISQ with a range of 0 to 100 (minimum to maximum stability). b Displays the results obtained by the torque in and c by the torque out test. Although, there was no statistically s...
Figure 2. Over-dimensioned protocol. The over-dimensioned protocol was conducted by a final drill of 1 mm narrower than the implant diameter. The final drill for implants of 3.3. mm was 3.2 mm and of implants measuring 3.75 mm, it was 3.65 mm. Within this study, an over-dimensioned protocol was defined as a final drill larger than recommended by the company, which is in this case 4 o...
Figure 1. Standard protocol. This figure shows the implant types and drilling protocol used within this study. Standard protocol was conducted by a final drill of 2.80 mm for 3.3 mm implants, 3.20 mm for 3.75 mm implants, and 3.65 mm for 4.2 mm implants. Permissions for reproducing the figures were received from HI-TEC IMPLANTS LTD. Source: Product Catalogue 12th Edition [40]
3.3 mm
3.75 mm
4.2 mm
Mean (SD)
CI
Mean (SD)
CI
Mean (SD)
CI
ISQ
66.33 (4.59)
63.79–68.88
69.00 (5.98)
64.72–73.28
69.87 (8.88)
64.94–74.78
IT (Ncm)
102.65 (28.42)
86.91–118.39
90.97 (27.54)
71.27–110.67
78.19 (33.28)
59.76–96.62
TO (Ncm)
94.54 (29.09)
78.43–110.65
81.28 (28.89)
60.67–101.88
100.86 (36....
8.0 mm
10.0 mm
11.5 mm
13.0 mm
16.0 mm
Mean (SD)
CI
Mean (SD)
CI
Mean (SD)
CI
Mean (SD)
CI
Mean (SD)
CI
ISQ
65.5 (8.40)
58.48–72.52
73.17 (3.60)
69.39–76.95
67.11 (6.09)
62.43–71.79
66.15 (8.15)
59.43–73.07
70.67 (4.97)
66.84–74.49
IT (Ncm)
98.23 (18.56)
82.71–113.74
99.49 (43.73)
53.60–145.48
101.02 (36.80)
72.74–...
Insertion mode — manual insertion
Insertion mode — machine-driven insertion
n
Mean (SD)
CI
n
Mean (SD)
CI
ISQ
45
68.33 (6.83)
66.14–70.51
45
70.25 (5.52)
68.38–72.12
IT (Ncm)
45
90.56 (31.27)
80.56–100.56
45
83.94 (31.81)
73.17–94.7
TO (Ncm)
45
93.59 (32.3)
83.27–103.92
45
89.80 (37.32)
77.18–102.43
ISQ impla...
Drilling sequence — standard protocol
Drilling sequence — over-dimensioned protocol
n
Mean (SD)
CI
n
Mean (SD)
CI
ISQ
45
68.33 (6.83)
66.14–70.51
30
68.5 (8.82)
65.08–71.92
IT (Ncm)
45
90.56 (31.27)
80.56–100.56
30
63.74 (48.61)
44.89–82.59
TO (Ncm)
45
93.59 (32.3)
83.27–103.92
30
58.35 (40.43)
42.67–74.02
ISQ im...
Contrary to the research hypothesis, there was no difference in primary stability between manually and machine-driven inserted implants. To date, little is known about the influence of the insertion mode on the dental implant primary stability. Novsak et al. assumed a better primary stability in implants inserted manually and suspected that this behavior was related to a higher tac...
However, caution is recommended when using under-dimensioned drilling protocols: although high insertion torques ensure a greater initial implant stability and prevent adverse micromotions under loading, the induced over-compression could jeopardize the healing process. In addition, high stress is known to alter angiogenesis and impair new vessel formations, to induce local hypoxia and n...
Discussion
This study was performed in order to investigate changes in primary stability within an experimental setup of different insertion protocols and insertion modes. In order to obtain a high level of diagnostic certainty, three different methods for measurement of primary stability were recorded. As a secondary outcome parameter, potential differences between implants of different le...
Results
Drilling protocol: standard versus over-dimensioned
No statistically significant difference in RFA could be measured (Cohen’s d = − 0.022, effect size r = 0.011, p = 0.260), whereas IT values were significantly higher in implants inserted via SP (90.56 ± 31.27 Ncm) in comparison with the ODP (63.74 ± 48.61 Ncm, p = 0.002; Cohen’s d = 0.656, effect size r = 0.312). T...
Preparation protocol for oversized osteotomies (ODP)
This protocol repeated the steps of the standard protocol but then added a larger final drill. For the 3.3-mm implants, the final drill size was 3.2 mm; for the 3.75-mm implants, the final drill size was 3.65 mm (Fig. 2).
RFA
To analyze the data, an Osstell® SmartPeg threaded transducer (implant diameter 3.3 and 3.75 mm: SmartPeg Type ...
Methods
Bone specimens
Twenty mandibles from fresh porcine cadavers were obtained from a local slaughterhouse. The animals did not show any macroscopic signs of any pathologic bone conditions. After removal of the surrounding soft tissue, the surfaces of the bone samples were thoroughly cleaned. Each sample was checked macroscopically for irregularities and a minimum thickness of 20 mm at th...
Analyzing those, a decrease in primary and an increase in secondary stability with a shorter healing period for implants became apparent. Kim et al. compared the effect of oversized drilling sockets regarding bone-to-implant contact and bone density after 4 and 8 weeks in an in vivo dog model. They used a final drill of 4.00 mm for implants with a diameter of 4 mm in the oversized group and a ...
With increasing stiffness of the bone-implant interface, the vibration frequency of the sensor increases. While RFA is expressed in hertz, implant stability quotient (ISQ) is the scale used to quantify RFA values (range 1–100).
Even though RFA has been reported to be a reliable, reproducible, and objective method to measure the stiffness of bone-implant-complex, it has also been reported that R...
Background
A reliable option for replacing teeth is the insertion of osseointegrated implants. Dental implant primary stability (DIS) has also been reported to be a fundamental prerequisite for long-term success of dental implants, even though osseointegration has also been achieved without a certain amount of primary stability. Primary stability has been defined as the ability to withstand axi...
Abstract
Background
Dental implant primary stability is thought to be a fundamental prerequisite for the long-term survival and success. The aim of this study was to analyze the influence of protocol and insertion mode on dental implant stability ex vivo. One hundred and twenty implants were inserted either manually or machine-driven into porcine mandibles by a standard or over-dimensioned pro...
Figure 50. Buccal wall
The margin of the buccal wall is shifted apically by approximately 2 mm over the 8 weeks of healing, as indicated by the yellow arrow. Bone loss is greater in the buccal wall than in the lingual wall during socket healing for several reasons. First, the crestal portion of the buccal bone wall, especially in the anterior region, is occupied by bundle bone. As mentioned e...
Figure 49. Dimensional ridge alternation : 8 weeks
At 8 weeks after tooth extraction, the entrance to the extraction site is bridged with cortical bone. The woven bone in the socket is replaced with bone marrow and some trabeculae of lamellar bone. At the crests of the buccal and lingual cortical plates, there are signs of ongoing bone resorption.
Figure 48. Dimensional ridge alterations: 4 weeks
At 4 weeks after tooth extraction, the socket is filled with woven bone. Osteoclasts are present on the outer surfaces at the margin of the buccal and lingual walls, signaling resorption of cortical plates. The resorption of the bundle bone is almost complete. Osteoclasts also line the trabeculae of woven bone present in the central and latera...
Figure 47. Dimensional ridge alterations: 2 weeks
At 2 weeks after tooth extraction, the apical and lateral parts of the socket are filled with woven bone, while the central and marginal portions of the socket are occupied by provisional connective tissue. On the inner and outer surfaces of the socket walls, numerous osteoclasts can be seen. In several areas of the socket wall, the bundle bon...
Figure 46. Dimensional ridge alterations in 1 week
Araujo and Lindhe described the edentulous ridge profile alterations following tooth extraction in an experimental study in a dog model. During the first week of post-extraction healing, the socket area is occupied by coagulum and granulation tissue. A large number of osteoclasts are seen on the outer as well as on the inner s...
Figure 45. Radiographic height reduction
The mean crestal height change as assessed on the radiographs was 1.53 mm.
Figure 44. Mean height reduction
The mean reduction in height was approximately 1.7 mm.
Figure 43. Mean width reduction
The weighted means showed that the clinical loss in width is greater than the loss in height. The mean reduction in width of the alveolar ridge was calculated to be approximately 4 mm.
Figure 42. Dimensional change in alveolar bone
A recent systematic review evaluated the amount of change in height and width of the residual ridge after tooth extraction.
Figure 41. Decrease in ridge width
On the contrary, the width of the alveolar ridge in single-rooted teeth will be decreased approximately by 50%, and two-thirds of this reduction will occur within the first 3 months after tooth extraction.
Figure 40. Decrease in ridge height
Studies utilizing clinical or cast model measurements have shown that the reduction in ridge dimensions is three-dimensional, but it is greater along the buccal surface than along the lingual or palatal surfaces. Changes in bone height are usually moderate. For example, Schropp and colleagues observed that, after 12 months of healing, the height of the ...
Selama berabad-abad, manusia mengandalkan pekerjaan manual untuk membuat gigi palsu. Era cetak gigi palsu manual sudah hampir berakhir dengan ditemukannya printer 3 dimensi yang bisa digunakan untuk mencetak gigi palsu langsung dari komputer. Dokter gigi hanya perlu seperangkat komputer lengkap dengan printer 3 dimensi dan bahan untuk membuat gigi palsu, maka dengan menekan tombol print saja, gi...