Resonance frequency analysis
Implant stability quotient
The datasets used and analyzed during the current study are available from the corresponding author on reasonable request.
The null hypothesis that finger tightening of transducer devices for RFA analysis may have a negative impact on the accuracy of ISQ measurements was rejected. Different forces applied during transducer tightening by different clinicians had no significant effect on the resulting ISQ values. Manual tightening of smartpeg magnetic devices allows for an objective and reliable determination of ISQ val...
A great number of studies have summarized that the measurement of implant stability with RFA is reliable, is noninvasive, and can be used at any time after implant insertion and during follow-up [19, 20]. Various parameters have been demonstrated to influence the degree of primary implant stability [21, 22]. These include bone density [23, 24], surgical technique [25], implant insertion torque [26...
In the test group, mesial and buccal ISQ values of 30 implants were recorded by four examiners (S1–S4) after hand tightening the smartpegs. The control group considered mesial and buccal ISQ values of 30 implants with mechanically inserted smartpegs. Only 147 values could be recorded because one transducer broke and thereafter no further values could be obtained for this implant. At torque value...
Statistical analysis was performed to evaluate the difference between the test and control group. Variance analysis and continuous variables were determined. Pearson r correlation coefficient was tested to verify the relationship between the two variables (e.g., relationship between torque and ISQ). Statistical significance was set at p > 0.05.
Three fresh bovine ribs from the same animal were selected for the current in vitro testing; the bovine ribs were of a similar size to those used by Gecikli et al. [16], thus attempting to imitate human edentulous bone with a similar composition of cortical and cancellous bone. The animal was farmed and sacrificed for food production. The bone was stored airtight, humid, and cool from the time the...
While dental implants have become increasingly important in the functional and esthetic rehabilitation of patients, implant failure still does occur. Primary stability at the time of implant placement and the development of osseointegration in the following healing process (secondary stability) are essential parameters for implant success [1]. Primary stability can be considered as the biomechanic...
There is disagreement about the optimal torque for tightening smartpegs for resonance frequency analysis (RFA). Subjective finger pressure during hand tightening could affect the reliability of the resulting values. The aim of the current study was therefore to assess whether or not the insertion torque of a smartpeg magnetic device influences the implant stability quotient (ISQ) value during RFA....
Fig. 3. One possible missing category (depicted as “X”) would be a bone type with thick cortical layer and sparse trabecular bone, which would have intermediate characteristics and behavior between the types with thick (2) or thin (3) cortical bones
Fig. 3. One possible missing category (depicted as “X”) would be a bone type with thick cortical layer and sparse trabecular bone, which ...
Fig. 2. Preoperative CT image showing the site for the definition of the ROI (simulated area delimited by a yellow dashed line for illustration purpose) in the axial (a), coronal (b), and sagittal (6 × 6 mm) (c) sections
Fig. 2. Preoperative CT image showing the site for the definition of the ROI (simulated area delimited by a yellow dashed line for illustration purpose) in the axial (...
Fig. 1. Clinical case of a short implant (4.1 × 6 mm) placed in the region of the left maxillary first molar. a Implant installed. b Insertion torque measurement using the manual torque wrench. c Implant with healing cap and flap suture. d Immediate periapical radiograph after surgery
Fig. 1. Clinical case of a short implant (4.1 × 6 mm) placed in the region of the left maxillar...
Variable
Meana
Std error
95% confidence interval
P value (F; DF)
Arch
Variables
Torque
Tactile
CT visual
MGV_avg
MGV_axial
M...
Variable
Frequency
Mean
SD
95% confidence interval
Patient
...
Triches, D.F., Alonso, F.R., Mezzomo, L.A. et al. Relation between insertion torque and tactile, visual, and rescaled gray value measures of bone quality: a cross-sectional clinical study with short implants.
Int J Implant Dent 5, 9 (2019). https://doi.org/10.1186/s40729-019-0158-6
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Received: 07 October 2018
Accepted: 06 January 2019
Published: 11 February...
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...
This study was conducted in accordance with the tenets of the Declaration of Helsinki, and all procedures involving human subjects were approved by the ethics committee of the Pontifical Catholic University of Rio Grande do Sul/UBEA (ethical approval letter OF.CEP-772/10; research protocol CEP 10/05074).
Written informed consent was obtained from all study participants.
Diego Fernandes Triches, ...
All authors (1) made substantial contributions to the conception and/or design of the work or the acquisition, analysis, or interpretation of data for the work; (2) drafted the paper or revised it critically; (3) approved the final version of this manuscript; and (4) agreed to be accountable for all aspects of the work. Categories of authors’ contribution are as follows: concept/design (RSS, DFT...
Postgraduate Program in Dentistry, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Dental School, Avenida Ipiranga, 6681 – Prédio 6, Porto Alegre, RS, 90619-900, Brazil
Diego Fernandes Triches, Fernando Rizzo Alonso, Danilo Renato Schneider, Eduardo Aydos Villarinho, Maria Ivete Rockenbach, Eduardo Rolim Teixeira & Rosemary Sadami Shinkai
Postgraduate Program in Dentistry,...
The authors would like to thank Professor Helena de Oliveira and Dr. Geisa Medeiros for their early assistance with CT software.
The work was supported by a research grant from Coordination for the Improvement of Higher Education Personnel (CAPES, Brazil; PNPD grant), the National Counsel of Technological and Scientific Development (CNPq, Brazil; Universal grant), and the International Team for I...
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Tatli U, Salimov F, Kürkcü M, Akoğlan M, Kurtoğlu C. Does cone be...
Nomura Y, Watanabe H, Honda E, Kurabayashi T. Reliability of voxel values from cone-beam computed tomography for dental use in evaluating bone mineral density. Clin Oral Implants Res. 2010;21:558–62.
Reeves TE, Mah P, McDavid WD. Deriving Hounsfield units using gray levels in cone beam CT: a clinical application. Dentomaxillofac Radiol. 2012;41:500–8.
Cassetta M, Stefanelli LV, Pacifici A, P...
Degidi M, Daprile G, Piattelli A. Determination of primary stability: a comparison of the surgeon’s perception and objective measurements. Int J Oral Maxillofac Implants. 2010;25:558–61.
Alonso FR, Triches DF, Mezzomo LAM, Teixeira ER, Shinkai RSA. Primary and secondary stability of single short implants. J Craniofac Surg. 2018. https://doi.org/10.1097/SCS.0000000000004567.
Ribeiro-Rotta RF,...
Cone beam computed tomography
Computed tomographic
Digital Imaging and Communications in Medicine
Field of view
Mean gray values
Region of interest
In summary, within the conditions and limitations of this study, the results suggest that bone quality has a significant effect on the primary stability of short implants as measured by insertion torque. Insertion torque had significant correlation with all assessment methods of bone quality. For preoperative CT evaluation of bone quality, mean gray values (optical density) had stronger associatio...
The present study also used the same preoperative CT images for visual evaluation of bone quality at the exact implant site, using the axial, coronal, and sagittal sections in a standardized procedure. There was a fairly moderate correlation between CT visual assessment and mean gray values, but no statistical difference was found in average mean gray values between the visual classification of bo...
In this study, low- and medium-density values (air and a central FOV soft tissue) were used as reference calibration points for image normalization. The use of a reference object in the FOV containing at least two materials of known density could allow for a calibration similar to the use of reference phantoms in quantitative CT, rather than the “standard” automatic normalization function avai...
This study showed that low bone quality, as assessed by clinical and image methods, is related with low primary stability of 6-mm short implants placed at the posterior region of the maxilla and mandible. Higher insertion torque values were associated with better bone types and higher mean gray values in CT images. Insertion torque had a negative moderate association with bone type categorization ...
Descriptive statistics of the sample are shown in Table 1. For statistical analysis, some data were missing: one implant had mobility after surgery and was lost and four CT scans, containing 11 ROIs, were not used for bone quality analysis due to technical problems. As only one case was categorized as bone type 1 by CT visual or by tactile evaluation, the corresponding mean gray values were exclu...
The mean gray value of each rescaled ROI was measured on the three orthogonal planes: axial, coronal, and sagittal, totaling three ROIs per implant site. The average of the rescaled gray values for the three ROIs was computed for each implant site.
Data were analyzed by descriptive and inferential statistics using the software XLSTAT version 2018 (Addinsoft SARL, New York, USA), and a two-tailed ...
Axial ROI: Using the reference implant location line, the ROI was defined as the alveolar bone area with a 6-mm width corresponding to 3 mm on each side of the future implant center, including the buccal and lingual cortical layers.
Coronal ROI: Area defined by the outer border of the cortical bone with a 6-mm height and a line joining the buccal and lingual cortical layers.
Sagittal ROI: A 6...
The insertion torque was measured using the manual torque wrench (Straumann Dental Implant System®, Waldenburg, Switzerland) (Fig. 1b), according to three categories: 35 N cm. A healing cap was installed, and the suture was made with nylon 5-0 (Fig. 1c). The patients were prescribed with antibiotics (amoxicillin 500 mg, 8/8 h for 7 days), anti-inflammatory drugs (nimesulide 100 mg,...
This study reports cross-sectional, correlational data of a prospective clinical research project [2] approved by the university Institutional Review Board (10/05074). The research protocol followed the precepts of the Declaration of Helsinki and its amendments. All patients signed an informed consent form.
A consecutive, non-probabilistic sample consisted of 45 implants placed in 20 patients tre...
Both multislice CT and cone beam CT are used for presurgical assessment of bone density and quality [4,5,6,7,8,9,10,11]. There is a strong correlation between gray values in cone beam CT and Hounsfield units in multislice CT [4, 12,13,14]. The visual inspection of CT sections avoids the superimposition of anatomical structures seen in radiographs; thus, the region of interest in trabecular bone ca...
The early clinical success of short implants can be affected by poor bone quality and low primary stability because implant micromovement can promote the formation of a fibrous capsule during the osseointegration process. It has been reported that the greater the insertion torque, the greater the resistance of the bone-implant interface to the shear forces that tend to rotate the implant [1]. Clin...
This study assessed the relationship between insertion torque and bone quality evaluated during surgery and in preoperative computed tomographic (CT) images analyzed either visually or by rescaled mean gray values (MGVs). The study also tested the correlation between the clinical and radiographic measures of bone quality.
The consecutive sample was composed of 45 short implants (4.1 × 6 mm...
Fig. 9. The comparison of two groups at average voxel values for each part. The comparison of voxel values by insertion torque. All specimens were classified into two groups by insertion torque
Fig. 8. The relationship between average voxel value and insertion torque (averaged over the entire treatment area). The comparison of average voxel value among IT groups. Average voxel value was 384.0 ± 154.6 in the low IT group, 387.7 ± 147.7 in the medium IT group, and 619.2 ± 200.4 in the high IT group
Fig. 8. The relationship between average voxel value and insertion torqu...
Fig. 7. The average voxel value between the maxilla and mandible. There was no difference between the maxilla (430.9 ± 211.6) and the mandible (475.6 ± 211.5) in the average voxel value. Also, no difference was found in each part
Fig. 7. The average voxel value between the maxilla and mandible. There was no difference between the maxilla (430.9 ± 211.6) and the mandible (475.6...
Fig. 6. The relationship between ISQ and insertion torque. Percentage of specimens showing ISQ ≥ 73 compared with groups by week. In all groups, a period of rapidly increasing percentages was observed (8–12 weeks in the low IT group, 4–6 weeks in the medium and high IT groups). In the medium and high IT Group, a statistically significant difference was observed between ISQ ≥ 73 a...
Fig. 5. The comparison of ISQ values by the insertion torque. Time-lapse migration of ISQ values was compared with IT groups. Each IT group displayed similar migration. A significant difference in The ISQ was found in the low IT group after 8 weeks
Fig. 5. The comparison of ISQ values by the insertion torque. Time-lapse migration of ISQ values was compared with IT groups. Each IT group displ...
Fig. 4. The classification of the insertion torque. All specimens classified into three groups according to insertion torque. Criteria for the classification are shown in the figure and in the “Methods” section
Fig. 4. The classification of the insertion torque. All specimens classified into three groups according to insertion torque. Criteria for the classification are shown in the figur...
Fig. 3. The evaluation of the average ISQ. Time-lapse migration of average ISQ. Average ISQ of all specimens increased in a time-dependent manner (results indicated by a line). A significant difference was observed by 6 weeks after surgery
Fig. 3. The evaluation of the average ISQ. Time-lapse migration of average ISQ. Average ISQ of all specimens increased in a time-dependent manner (results...
Fig. 2. The measurement of the voxel values. A case of bone quality diagnosis before treatment. Width and height of the bone were measured to select the proper size of the implant body. The selected implant body was simulated on the bone images as a symbol, and then the voxel value was calculated as described in the “Methods” section
Fig. 2. The measurement of the voxel values. A case of ...
Fig. 1. Genesio® Plus implant with Aanchor surface. Scheme of the dental implant body for the Genesio® Plus implants with Aanchor surface used. a Overview picture of Genesio® Plus implants with Aanchor surface. b Image from scanning electron microscopy. Both pictures were provided by GC Corporation. To obtain osseointegration from an early stage, the dental implant body was treated with sandb...
Number of implants
Insertion torque value (N cm)
Implant stability quotient value
0 week
2 weeks
...
Number of implants
Treatment area (FDI)
Size of implant (mm)
Length
Diameter
1
...
Homma, S., Makabe, Y., Sakai, T. et al. Prospective multicenter non-randomized controlled study on intraosseous stability and healing period for dental implants in the posterior region.
Int J Implant Dent 4, 10 (2018). https://doi.org/10.1186/s40729-018-0122-x
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Received: 05 September 2017
Accepted: 25 January 2018
Published: 29 March 2018
DOI: https://doi...
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...
This research was conducted in accordance with the Helsinki Declaration of 1964 and subsequent ethical standards, with the approval of Tokyo Dental University and Fukuoka Dental College Ethics Committee (World Medical 2013). The surgeon explained the contents of the research to each patient, who then consented to participate in the present study.
All participants consented to publish their inform...
Correspondence to
Shinya Homma.
Department of Oral and Maxillofacial Implantology, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan
Shinya Homma, Yasushi Makabe & Yasutomo Yajima
Section of Oral Implantology, Department of Oral Rehabilitation, Fukuoka Dental College, 2-15-1 Tamura, Sawara-ku, Fukuoka-City, Fukuoka, 814-0175, Japan
Takuya Sakai, Kenzou Morinaga & Hirofumi Kido
Center for Oral ...
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Meredith N. Assessment of i...
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Cochran DL, Moeton D, Weber HP. Consensus statements and recommended clinical procedures regarding loading protocols for endosseous dental implants. Int J Oral Maxillofac ...
Cone beam CT
Computed tomography
Digital Imaging and Communications in Medicine
Implant stability quotient
Insertion torque
Multi-slice CT
The purpose of this study was to evaluate the relationship between the insertion torque value and the ISQ value at the implant treatment using the current rough-surfaced implant. As a result, no significant relationship was found between the insertion torque value and the ISQ value. Also, it was suggested that the ISQ value was considered to be an important indicator for observing the treatment st...
As accurate CT attenuation was not measured due to the lower spatial resolution of CBCT compared with MSCT, a CBCT was recognized as unsuitable for evaluating bone quality. However, several groups have recently reported the potential use of CBCT systems as an apparatus for estimating bone quality. Isoda et al. described a high correlation between voxel values obtained by CBCT and IT of the implant...
In this study, we could not find a significant relationship between insertion torque value and ISQ value. However, insertion torque value is an important indicator for predicting the progress of implant treatment, and ISQ value is considered to be an important indicator for observing the treatment state of the implant. Currently, the insertion torque value is used as the major decision index for t...
Increases or decreases of ISQ values are explained as follows: The inserted dental implant body is supported by mechanical interdigitating force after surgery, but this interdigitating force will be reduced time-dependently by the effects of osteoclasts activation at the initial stage of the bone remodeling process, then osseointegration will be completed by an increasing contact area between the ...
The insertion torque value in this study showed broader (10 to 50 N cm) than the previous publication (Table 2) [22, 32], and the cause of reasons for the difference are as follows: Primary stability may be affected by the bone quantity and bone quality in the treatment area, the micro- and macro-level design of the implant body, and the accuracy of the surgical technique [18, 25]. In this stud...
According to the previous literature, the obtaining osseointegration is integral to the intraosseous stability of the implant body during the healing period [24]; moreover, the importance of postoperative assessment of the intraosseous stability of the implant has also been reported [10]. Intraosseous stability of the implant body is evaluated immediately after the implant insertion and during the...
Average ISQ tended to increase during the healing period in all IT groups (Fig. 5). Average ISQ of the low IT group was 59.81 at 0 week, increasing significantly after ≥ 8 weeks (P
A total of 33 implant bodies (8 in the maxilla, 25 in the mandible) were inserted into the 27 participants (11 men, 16 women), with the average age of 54.6 ± 12.2 years (range, 32–78 years). The average IT value was 32.7 ± 9.2 N cm (32.5 ± 11.6 N cm in the maxilla, 32.8 ± 8.5 N cm in the mandible). The diameter of the implant body was 4.4 mm in 20 (60.6%) and 3.8 mm...
The CBCT was performed using a 3DX Multi-Image Micro CT FPD 8 system (J. MORITA MFG., Kyoto, Japan) (tube voltage, 80 kV; imaging area, 80 × 80 mm), and voxel values were measured with coDiagnostix™ 9.7 (dental wings, Montreal, Canada). The voxel values were calculated based on CT images for bone quality diagnosis. Voxel values were measured three times at 12 locations covering the mesial...
Implant treatment was performed in accordance with the procedure recommended by the manufacturer, without bone augmentation. A healing abutment was connected to the implant bodies after insertion (implant insertion in one stage method). A total of 17 dentists (treatment experience, 5–35 years; average, 11.5 years) performed all implant treatments in this study. All dentists who performed the i...
This prospective study was conducted jointly by Tokyo Dental College (Tokyo, Japan) and Fukuoka Dental College (Fukuoka, Japan) from January to December 2015. All study protocols were conducted in accordance with the Declaration of Helsinki [21] and were approved by the ethics committees of Tokyo Dental College (approval #416) and Fukuoka Dental College (approval #213).
Participants comprised pat...
The purpose of this study is to evaluate the relationship between IT and ISQ at implant treatment using the current rough surfaced implant. We evaluated the implant treatment sites with implant stability quotient (ISQ) values, IT values, and voxel values. We assumed that there is relevance between the insertion torque value and the ISQ value.
Dental implant treatments have improved in both convenience and predictability with refinements in implant bodies and treatment procedures as compared to about 50 years ago when clinical applications were started. Currently, an implant body surface is treated with “rough processing” by sandblasting and acid etching for the purposes of obtaining more reliable osseointegration and shortening tr...
A current implant body surface was treated with “rough processing” by sandblasting and acid etching for the purposes of obtaining more reliable osseointegration and shortening the treatment period. Various reports have examined the healing period with the use of these implant bodies, but a consensus opinion has not yet been obtained. The purpose of this study is to evaluate the relationship be...
A current implant body surface was treated with “rough processing” by sandblasting and acid etching for the purposes of obtaining more reliable osseointegration and shortening the treatment period. Various reports have examined the healing period with the use of these implant bodies, but a consensus opinion has not yet been obtained. The purpose of this study is to evaluate the relationship be...
Code
IT(N•cm)
RT(N•cm)
ISQ
12S
13.67 (1.88)
11.68 (1.06)
51.40 (2.95)
06D
20.19 (1.61)
17.45 (1.28)
53.77 (2.73)
06S
22.30 (1.78)
20.25 (2.47)
55.66(1.62)
Implant code
Thread type
Pitch (mm)
Lead (mm)
Lead angle (degree)
Total thread length (mm)
12S
Single-threaded
1.2
1.2
8.1
64
06D
Double-threaded
0.6
1.2
8.1
129
06S
Single-threaded
0.6
0.6
4.65
129
Figure 6. Bone debris at the contact interfaces. a Numbers of debris particles. b Number and size of debris particles. Each dot indicates a debris particle, and dashes indicate median particle sizes. Particle sizes: small, < 1000 μm2; medium, 1000–10000 μm2, and large, ≥ 10,000 μm2. c Particle size distribution
Figure 5. Microscopic analysis of contact interfaces. Microscopic observations of the artificial bone-implant and number of debris particles. The small arrows in the panel indicate voids in the implant-bone interface
Figure 4. Torque kinetics. Immediately after insertion terminated, the implant was removed using the same load and rotation speed. Torque kinetics were measured during implant insertion (top) and removal (bottom)
Figure 3. Comparison between IT and RT. Maximum IT value was measured when insertion was terminated. Immediately after insertion, the implant was removed, and the RT value was measured when removal commenced
Figure 2. Insertion torque (IT), removal torque (RT), and implant stability quotient (ISQ)
Figure 1. Implants. Implant code 12S is similar to a commercially available standard single-threaded implant with equal thread pitch and a 1.2-mm lead. The thread length of implant code 06D is doubled by adding the second thread (light blue). The thread length of implant code 06S is doubled by a 50% reduction in pitch and lead angles. Characteristics of each implant are summarized in Table 1
Fi...
References
Javed F, Ahmed HB, Crespi R, Romanos GE. Role of primary stability for successful osseointegration of dental implants: factors of influence and evaluation. Interv Med Appl Sci. 2013;5:162–7.
Falco A, Berardini M, Trisi P. Correlation between implant geometry, implant surface, insertion torque, and primary stability: in vitro biomechanical analysis. Int J Oral Maxillofac Implan...
Although bone models composed of a combination of cortical and cancellous bone are also available, this study used a single bone model with a homogeneous density to eliminate any effect of cortical bone and evaluate only the effect of design features on torque and ISQ values.
Experimental implant placement using artificial bone models is generally conducted to si...
Clinicians are advised to recognize the risk associated with using a multithreaded implant with a high lead angle, which may compromise primary stability because of greater bone tissue damage despite faster insertion. The question of placement speed warrants further consideration. Indeed, another advantage of double-threaded implants is placement speed. The implantation speed...
Moreover, the IT and RT values of 12S were consistent with those of the standard implant (Straumann) measured in our previous study. Here, the RT value of each implant was lower compared with their respective IT values, consistent with other reports. The IT and RT values of 06S were highest, followed by 06D and 12S. In contrast, the differences between RT and IT values were highest for...
In the artificial bone adjacent to 06D, there were more voids compared with those associated with 06S or 12S, which accounts for the increase in torque. The highest numbers and larger sizes of debris particles were associated with 06D, followed by 0S and 12S, indicating the potential for greater tissue damage. These results likely explain the lower (50%) torque value of 06S compared with tho...
Discussion
We show here that increasing thread length and reducing pitch can increase primary implant stability without changing the size of an implant. Compared with the standard single-threaded implant with a 1.2-mm pitch/lead (12S), torque values and ISQ were significantly increased by doubling the thread length by adding the second thread (06D) or by reducing pitch/lead and lead angle o...
Results
The IT, RT, and ISQ values revealed significant differences among the implants (Table 2).
The IT and RT values of 12S were not significantly different compared with published data (IT, 13.13 ± 1.763 N cm; RT, 12.37 ± 1.746 N cm) (Student t test, df = 9, t = 2.91, p < .017). Compared with 12S, the IT and RT values of 06D and 06S were significantly different (147% and 150%, a...
Methods
Implants
Three types of grade-4 titanium cylindrical nonself-tapping implants (codes 12S, 06D, and 06S) were specially designed and manufactured (Suwa Co., Ltd., Fujiyoshida, Yamanashi, Japan) (Fig. 1 and Table 1). The code 12S single-threaded implant served as a reference. Codes 06D and 06S were designed to double the thread length compared to 12S. Code 06D was a double-threated impla...
Introduction
Secure primary stability is positively associated with successful long-term implant integration to ensure a successful clinical outcome. Initial implant stability is defined as biomechanical stability upon insertion, which is influenced by factors such as bone quantity and quality, geometry of the implant, surgical technique, and insertion torque (IT). New bone develops around the ...
Effects of implant thread design on primary stability—a comparison between single- and double-threaded implants in an artificial bone model
Abstract
Background
Primary implant stability is essential for osseointegration. To increase stability without changing the implant size, the thread length must be extended by reducing pitch, using a double-threaded implant, or reducing pitch/lead a...
Figure 5. Torque-time curves of the MK3 and MK4. a Insertion torque. b Removal torque
Figure 4. Torque-time curves of the TE. a Insertion torque. b Removal torque
Figure 3. Torque-time curves of the BL. a Insertion torque. b Removal torque
Figure 2. Torque-time curves of the ST. a Insertion torque. b Removal torque
Figure 1. Compressed longitudinally to one third for characteristics of implant design. ST Straumann standard implant, MK3 Nobel Biocare MKIII, BL Straumann bone level implant, TE Straumann tapered effect implant, MK4 Nobel Biocare MKIV. Outer surface of implant (solid line). Inner surface of implant (dotted line)
Figure 1. Compressed longitudinally to one third for characteristics of implant d...
Initial area
Parallel area
Tapered area
Platform area
ST6
1.42 ± 0.43
0.31 ± 0.14
–
–
ST8
3.57 ± 1.62
0.35 ± 0.09
–
–
ST10
2.49 ± 0.81
0.45 ± 0.05
–
–
BL8
2.16 ± 0.21
0.50 ± 0.08
2.32 ± 0.52
–
BL10
1.96 ± 0.49
0.35+0.04
2.45+0.23
–
BL12
1.82 ± 0.27
0.33 ±...
Code
Insertion torque
Removal torque
Effective thread length (ETL)
(N · cm)
(N · cm)
(×π mm)
ST6
6.19 ± 0.716
5.95 ± 0.718
11.53
ST8
8.06 ± 1.038
9.09 ± 1.093
15.11
ST10
13.13 ± 1.763
12.37 ± 1.746
21.48
BL8
17.67 ± 1.290
16.67 ± 2.140
20.88
BL10
23.56 ± 1.628
21.99 ± 1.530
31....
System
Length
Pitch
Lead
Code
Manufacturer
(mm)
(mm)
(mm)
Standard RN
6, 8, 10
1.2
1.2
ST
Straumann
Bone Level RC
8, 10, 12
0.8
0.8
BL
Straumann
Tapered Effect RN
10
0.8
0.8
TE
Straumann
Brånemark MKIII
10
0.6
1.2
MK3
Nobel Biocare
Brånemark MKIV
10
0.6
1.2
MK4
Nobel Biocare
Abbreviations
BL:
Bone Level RC
IT:
insertion torque value
MK3:
Brånemark MKIII
MK4:
Brånemark MKIV
RT:
removal torque value
ST:
Standard RN
TE:
Tapered Effect RN
References
Friberg B, Sennerby L, Roos J, Johansson P, Strid CG, Lekholm U. Evaluation of bone density using cutting resistance measurements and microradiography. An...
Influence of cortical bone
The reason why a simulation test for only cancellous bone without cortical bone was performed in the present study has already been described. It was reported that bone density and the ratio of cortical bone and cancellous bone have influence on the primary stability of an implant and that higher primary stability is achieved with thread, even at the slightest lev...
Although the removal torque curves measured in the present study had similar shapes to one another, they were divided into two groups upon detailed observation, comprising a group of ST with parallel only, and a group of BL, TE, MK3, and MK4 having tapers and platforms. Since the thread contacts the artificial bone sequentially at the time of insertion, the torque curves showed the character...
This indicates that the friction at the time of rotating and pressing is greater than that at the time of rotating and cutting the bones with a tap and is a reasonable result. In the parallel area, the torque curve was a line with a moderate gradient, and the torque rise rate obtained from the gradient of the line was 0.36 N · cm/s. From this, it is estimated that the torque increase w...
Discussion
Insertion torque curve
In 2000, O’Sullivan reported torque curves for a prosthetic implant for the first time, and evaluated the characteristics of the tapered type by torque curves obtained by inserting five kinds of implants into the maxillary bone of unembalmed human cadavers. In a subsequent review, Meredith cited six kinds of torque curves when the final osteotomy diamete...
For the TE, the lower part of the implant was parallel and the lateral surface and axial surface had the same taper in the cervical region. TE10 in Fig. 4a showed a torque curve with a similar form to BL10 in Fig. 3 and had three kinds of areas. The torque curves for MK3 and MK4 in Fig. 4a had an area in which the torque finally rose suddenly after reaching its critical point and became moderate...
Results
Insertion torque
The insertion torque curve was divided into four regions. The first was the region where the torque rose suddenly immediately after insertion, which was seen in all implant bodies (shown as ① in the figure, and hereinafter called the initial area). The second was the region where the torque rose linearly with a moderate gradient, which was seen in all implant bodie...
Methods
Implants
The type of implant used for the experiments and the characteristics of its design are shown in Table 1 and Fig. 1, respectively. Figure 1 shows that the implant is compressed longitudinally to one third. The outer surface of the implant is indicated with a solid line, and the inner surface of the implant is indicated with a dotted line.
Preparation of an implant socket in ...
Background
Primary stability following implant placement is an essential condition for osseointegration. The primary stability is affected by the implant design, including surface-modifying or implant cavity-forming techniques, as well as by the bone quantity and bone density of the patient. In recent years, the interest of implant manufacturers and clinicians has shifted to the acquisition of ...
Abstract
Background
Primary stability following implant placement is essential for osseointegration and is affected by both implant design and bone density. The aim of this study was to compare the relationships between torque-time curves and implant designs in a poor bone quality model.
Methods
Nine implant designs, with five implants in each category, were compared. A total of 90 implants ...
Number of implants
Insertion torque value (N cm)
Implant stability quotient value
0 week
2 weeks
4 weeks
6 weeks
8 weeks
12 weeks
1
25
33.0
75.0
77.0
78.3
79.7
77.0
2
40
68.0
70.3
70.0
72.0
75.7
75.3
3
40
78.3
77.0
78.0
78.7
80.0
80.0
4
35
74.0
43.0
61.0
73.0
75.7
80.0
5
45
85.3
85.7
84.0
83.3
84.0
83.0
6...
Number of implants
Treatment area (FDI)
Size of implant (mm)
Length
Diameter
1
14
10
3.8
2
14
10
3.8
3
14
10
3.8
4
16
8
3.8
5
16
10
4.4
6
16
8
4.4
7
16
8
4.4
8
17
10
4.4
9
36
10
3.8
10
36
10
4.4
11
36
8
3.8
12
36
10
3.8
13
36
12
4.4
14
36
10
4.4
15
36
10
4.4
...
Figure 9. The comparison of two groups at average voxel values for each part. The comparison of voxel values by insertion torque. All specimens were classified into two groups by insertion torque
Figure 8. The relationship between average voxel value and insertion torque (averaged over the entire treatment area). The comparison of average voxel value among IT groups. Average voxel value was 384.0 ± 154.6 in the low IT group, 387.7 ± 147.7 in the medium IT group, and 619.2 ± 200.4 in the high IT group
Figure 7. The average voxel value between the maxilla and mandible. There was no difference between the maxilla (430.9 ± 211.6) and the mandible (475.6 ± 211.5) in the average voxel value. Also, no difference was found in each part
Figure 6. The relationship between ISQ and insertion torque. Percentage of specimens showing ISQ ≥ 73 compared with groups by week. In all groups, a period of rapidly increasing percentages was observed (8–12 weeks in the low IT group, 4–6 weeks in the medium and high IT groups). In the medium and high IT Group, a statistically significant difference was observed between ISQ ...
Figure 5. The comparison of ISQ values by the insertion torque. Time-lapse migration of ISQ values was compared with IT groups. Each IT group displayed similar migration. A significant difference in The ISQ was found in the low IT group after 8 weeks
Figure 4. The classification of the insertion torque. All specimens classified into three groups according to insertion torque. Criteria for the classification are shown in the figure and in the “Methods” section
Figure 3. The evaluation of the average ISQ. Time-lapse migration of average ISQ. Average ISQ of all specimens increased in a time-dependent manner (results indicated by a line). A significant difference was observed by 6 weeks after surgery
Figure 2. The measurement of the voxel values. A case of bone quality diagnosis before treatment. Width and height of the bone were measured to select the proper size of the implant body. The selected implant body was simulated on the bone images as a symbol, and then the voxel value was calculated as described in the "Method" section
Figure 1. Genesio® Plus implant with Aanchor surface. Scheme of the dental implant body for the Genesio® Plus implants with Aanchor surface used. a Overview picture of Genesio® Plus implants with Aanchor surface. b Image from scanning electron microscopy. Both pictures were provided by GC Corporation. To obtain osseointegration from an early stage, the dental implant body was treated...
According to the measurement of the average voxel values in this study, a significant difference was seen between the high IT group and the low/medium IT group, but no significant difference was found between the low and medium IT groups (Fig. 7). Specimens showing IT ≥ 40 N cm were thought to have a good bone quality, and voxel values at each part of the implant (neck, middle apex) were...
A bone quality of the treated area may affect primary stability as described above, preoperative analysis of bone quality is important for clarifying the primary stability of dental implants. This study analyzed bone quality using voxel values obtained using Digital Imaging and Communications in Medicine (DICOM) data from CBCT. According to the result of that analysis, it was...
A significant difference was observed between 0 and ≥ 8 weeks (Fig. 5). The ISQ did not change significantly during the experimental period in the medium or high IT groups, but the percentage of high ISQ (≥ 73) specimens was significantly higher at 4 to 6 weeks compared to other time periods in both groups (Figs. 5 and 6). The results in this study suggest that if the...
Other studies have suggested that ISQ immediately after implant insertion should be about 60, with ISQ subsequently decreasing over weeks 0–4 and increasing over weeks 4–8 after surgery. ISQ values 57–70 may indicate that intraosseous stability of the implant body is constant.
Increases or decreases of ISQ values are explained as follows: The inserted dental implant bo...
The insertion torque value in this study showed broader (10 to 50 N cm) than the previous publication (Table 2), and the cause of reasons for the difference are as follows: Primary stability may be affected by the bone quantity and bone quality in the treatment area, the micro- and macro-level design of the implant body, and the accuracy of the surgical technique. In this ...
Discussion
According to the previous literature, the obtaining osseointegration is integral to the intraosseous stability of the implant body during the healing period; moreover, the importance of postoperative assessment of the intraosseous stability of the implant has also been reported. Intraosseous stability of the implant body is evaluated immediately after the implant ...
Average ISQ tended to increase during the healing period in all IT groups (Fig. 5). Average ISQ of the low IT group was 59.81 at 0 week, increasing significantly after ≥ 8 weeks (P
Methods
Research design and study participants
This prospective study was conducted jointly by Tokyo Dental College (Tokyo, Japan) and Fukuoka Dental College (Fukuoka, Japan) from January to December 2015. All study protocols were conducted in accordance with the Declaration of Helsinki and were approved by the ethics committees of Tokyo Dental College (approval #416) and Fukuoka Dental Colle...
Results
Study overview
A total of 33 implant bodies (8 in the maxilla, 25 in the mandible) were inserted into the 27 participants (11 men, 16 women), with the average age of 54.6 ± 12.2 years (range, 32–78 years). The average IT value was 32.7 ± 9.2 N cm (32.5 ± 11.6 N cm in the maxilla, 32.8 ± 8.5 N cm in the mandible). The diameter of the implant body wa...
Methods
Research design and study participants
This prospective study was conducted jointly by Tokyo Dental College (Tokyo, Japan) and Fukuoka Dental College (Fukuoka, Japan) from January to December 2015. All study protocols were conducted in accordance with the Declaration of Helsinki and were approved by the ethics committees of Tokyo Dental College (approval #416) and Fuku...
Background
Dental implant treatments have improved in both convenience and predictability with refinements in implant bodies and treatment procedures as compared to about 50 years ago when clinical applications were started. Currently, an implant body surface is treated with “rough processing” by sandblasting and acid etching for the purposes of obtaining more reliable osseo...
Abstract
Background
A current implant body surface was treated with “rough processing” by sandblasting and acid etching for the purposes of obtaining more reliable osseointegration and shortening the treatment period. Various reports have examined the healing period with the use of these implant bodies, but a consensus opinion has not yet been obtained. The purpose of this study is to eval...
Figure 6. Bone debris at the contact interfaces. a Numbers of debris particles. b Number and size of debris particles. Each dot indicates a debris particle, and dashes indicate median particle sizes. Particle sizes: small, < 1000 μm2; medium, 1000–10000 μm2, and large, ≥ 10,000 μm2. c Particle size distribution
Figure 5. Microscopic analysis of contact interfaces. Microscopic observations of the artificial bone-implant and number of debris particles. The small arrows in the panel indicate voids in the implant-bone interface
Figure 4. Torque kinetics. Immediately after insertion terminated, the implant was removed using the same load and rotation speed. Torque kinetics were measured during implant insertion (top) and removal (bottom)
Figure 2. Insertion torque (IT), removal torque (RT), and implant stability quotient (ISQ)
Table 2. Implants. Implant code 12S is similar to a commercially available standard single-threaded implant with equal thread pitch and a 1.2-mm lead. The thread length of implant code 06D is doubled by adding the second thread (light blue). The thread length of implant code 06S is doubled by a 50% reduction in pitch and lead angles. Characteristics of each implant are summarized in Table 1....
Code
IT(N•cm)
RT(N•cm)
ISQ
12S
13.67 (1.88)
11.68 (1.06)
51.40 (2.95)
06D
20.19 (1.61)
17.45 (1.28)
53.77 (2.73)
06S
22.30 (1.78)
20.25 (2.47)
55.66(1.62)
Implant code
Thread type
Pitch (mm)
Lead (mm)
Lead angle (degree)
Total thread length (mm)
12S
Single-threaded
1.2
1.2
8.1
64
06D
Double-threaded
0.6
1.2
8.1
129
06S
Single-threaded
0.6
0.6
4.65
129
The question of placement speed warrants further consideration. Indeed, another advantage of double-threaded implants is placement speed. The implantation speed of 06D was twice that of 06S, and implantation was completed twice as fast. Nevertheless, while plastic bottles and emergency valves have double-threaded screws for faster opening and closing, the effect...
Here, the RT value of each implant was lower compared with their respective IT values, consistent with other reports. The IT and RT values of 06S were highest, followed by 06D and 12S. In contrast, the differences between RT and IT values were highest for 12S, followed by 06D, and in 06S. We reported that the RT decreased more than IT. Thus, 06S had the lowest rate of decline (IT...
In the artificial bone adjacent to 06D, there were more voids compared with those associated with 06S or 12S, which accounts for the increase in torque. The highest numbers and larger sizes of debris particles were associated with 06D, followed by 0S and 12S, indicating the potential for greater tissue damage. These results likely explain the lower (50%) torque value of 06S compared wi...
In the artificial bone adjacent to 06D, there were more voids compared with those associated with 06S or 12S, which accounts for the increase in torque. The highest numbers and larger sizes of debris particles were associated with 06D, followed by 0S and 12S, indicating the potential for greater tissue damage. These results likely explain the lower (50%) torque value of 06S compared wi...
Discussion
We show here that increasing thread length and reducing pitch can increase primary implant stability without changing the size of an implant. Compared with the standard single-threaded implant with a 1.2-mm pitch/lead (12S), torque values and ISQ were significantly increased by doubling the thread length by adding the second thread (06D) or by reducing pitch/lead and lead angle o...
Results
The IT, RT, and ISQ values revealed significant differences among the implants (Table 2).
The IT and RT values of 12S were not significantly different compared with published data (IT, 13.13 ± 1.763 N cm; RT, 12.37 ± 1.746 N cm) (Student t test, df = 9, t = 2.91, p < .017). Compared with 12S, the IT and RT values of 06D and 06S were significantly different (147% and 150%, a...
Implants
Three types of grade-4 titanium cylindrical nonself-tapping implants (codes 12S, 06D, and 06S) were specially designed and manufactured (Suwa Co., Ltd., Fujiyoshida, Yamanashi, Japan) (Fig. 1 and Table 1). The code 12S single-threaded implant served as a reference. Codes 06D and 06S were designed to double the thread length compared to 12S. Code 06D was a double-threated implant with t...
Unfortunately, the effects of double- or triple-threaded implants on primary stability are known for only a few procedures, such as finite element analysis. An excessive lead angle for these implants may jeopardize their ability to sustain axial load despite faster insertion. Further, when micromotion is compared among implants with different lead angles with the same thread pitch, single-threaded...
Introduction
Secure primary stability is positively associated with successful long-term implant integration to ensure a successful clinical outcome. Initial implant stability is defined as biomechanical stability upon insertion, which is influenced by factors such as bone quantity and quality, geometry of the implant, surgical technique, and insertion torque (IT). New bone develops around the ...
Abstract
Background
Primary implant stability is essential for osseointegration. To increase stability without changing the implant size, the thread length must be extended by reducing pitch, using a double-threaded implant, or reducing pitch/lead and lead angle to half that of a single-threaded implant.
Materials and methods
We tested the stabilities of these configurations using artificial...
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...