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| ORIGINAL RESEARCH |
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| Year : 2022 | Volume
: 14
| Issue : 5 | Page : 487-493 |
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The effect of implant length and diameter on primary stability of tilted implant on D4 bone density: An in vitro study
Muhammad I Baihaqi, Taufik Sumarsongko, Setyawan Bonifacius
Department of Prosthodontic, Faculty of Dentistry, Universitas Padjadjaran, Jawa Barat, Indonesia
| Date of Submission | 24-Mar-2022 |
| Date of Decision | 29-Aug-2022 |
| Date of Acceptance | 29-Aug-2022 |
| Date of Web Publication | 31-Oct-2022 |
Correspondence Address:
Mr. Setyawan Bonifacius
Komplek Pasirlayung Asri, Blok A6, Bandung, Jawa Barat
Indonesia
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/jioh.jioh_65_22
Aim: To determine the effect of implant length and diameter on the primary stability of tilted dental implant and D4 bone density. Materials and Methods: Superline implant with different lengths (12 mm and 14 mm) and diameters (4 mm and 5 mm) as well as the path of placement inclinations (0°, 15°, 30°, 45°) were used in this true experimental study design with 48 samples and allocated into 16 groups with repeated three times (based on Federer’s formula). Artificial polyurethane bone blocks, 20 pounds per cubic foot (0.32 g/cm3), were prepared, and each implant was inserted following the manufacturer’s instruction. Primary implant stability was measured using Osstell tool. The procedure was repeated three times for each implant at four different 90° orientation or from buccal, lingual, mesial, and distal. The mean value for implant stability quotient (ISQ) was calculated using statistical analysis. Data distributed normally, and univariate analysis of variance was the statistical formula used to calculate any differences in the primary stability values of each group. Post hoc test was further utilized as a t-test to compare each group, which showed good scores for the primary stability. Results: The results of this study reveal that there was a significant difference in the primary stability of tilted implant at different lengths and diameters. Implants with a length of 14 mm and a diameter of 5 mm at 45° inclination resulted in the highest ISQ score with an average of 72.25. Implants with a length of 12 mm and a diameter of 4 mm at 15° inclination had the lowest ISQ score with an average of 63.58. Implants with an inclination of 45° showed no difference in the mean value of the primary stability against implants in the upright position (0°). Conclusion: The longer and wider the implants in the tilted position have better primary stability in D4 bone density. Keywords: Bone Density, Implant Length and Diameter, Primary Stability, Tilted Implant
How to cite this article:
Baihaqi MI, Sumarsongko T, Bonifacius S. The effect of implant length and diameter on primary stability of tilted implant on D4 bone density: An in vitro study. J Int Oral Health 2022;14:487-93 |
How to cite this URL:
Baihaqi MI, Sumarsongko T, Bonifacius S. The effect of implant length and diameter on primary stability of tilted implant on D4 bone density: An in vitro study. J Int Oral Health [serial online] 2022 [cited 2023 Mar 23];14:487-93. Available from: https://www.jioh.org/text.asp?2022/14/5/487/359970 |
| Introduction | |  |
Dental implant is a procedure to replace missing teeth using a material that is surgically implanted into the soft tissue or jaw bone so that it functions as a replacement of the root to hold the denture. One of the advantages provided by dental implants is its resemblance to natural teeth where the part of it is embedded in the tissue. This concept not only aids for esthetics, promotes retention, protects adjacent teeth, but also improves self-confidence.[1] The average success rate of dental implants is above 90%–95% within a period of 10 years. Although dental implant is the treatment of choice for several dentists in constructing dentures, the complications that arise and the factors that affect the installment of dental implants are the biggest challenges for successful treatment plan.[2],[3]
One of the challenges that need to be considered in the placement of dental implants is the quality of alveolar bone and vital anatomical structures. The quality of D4 bone density is usually described as poor because it is soft and difficult to achieve primary stability for implants.[4] The maxillary posterior bone density composed of D4 bone that mostly shows no cortices while it is arranged by soft trabecular.[5] The mean height of the remaining alveolar bone in the first molar region of 160 patients was 5.14 ± 3.36 and the second molar from 131 patients was 4.79 ± 2.69 mm.[6] A loss of teeth in the posterior region promotes bone resorption, which may lead to closer proximity to the inferior alveolar nerve structures and maxillary sinuses, thus limiting the use of standard implants.[7],[8],[9]
In recent decades, various alternative clinical procedures have been proposed to support the placement of dental implants in atrophic complete edentulous areas, especially in the posterior region, namely the utilization of short dental implants, maxillary sinus augmentation, bone grafting, and nerve repositioning. Apart from the excellent results of these procedures, they demonstrate several disadvantages, such as high invasiveness, increased surgical steps, increased working time, higher complications, and expensive.[7],[10] Another alternative has been offered is the placement of tilted implants. This technique aims to reduce the need of bone grafting procedures, prevent the perforation of maxillary sinus area and mental foramen, as well as to prevent the damage of mandibular nerve.[7],[8],[9],[10]
The success of the implant placement is strongly influenced by the primary stability of an implant. Primary implant stability was defined as the biomechanical stability of the implant immediately after its placement in the bone, i.e., the absence of mobility in the axial, lateral, and rotational directions of the bone base immediately after the implant was inserted. Resonance frequency analysis (RFA) is a noninvasive measurement tool to investigate the stiffness and stability of the implant–bone interface with a frequency of 5–15 kHz. These measurements range from 1 (lowest implant stability) to 100 (highest implant stability). The value of the primary stability in implant placement must be above 60 to achieve adequate implant stability.[11] Three parameters to obtain primary stability are implant design, surgical technique, and quality of bone.[12],[13],[14]
Implant design is generally the key to successful implant placement and affects the primary stability of the implant. The most important biomechanical factors in the implant design at the implant–bone interface are the length and diameter of the implant. The optimal length and diameter required for long-term implant success depend on the quality of the bone support.[15],[16] However, the relationship between length and diameter of dental implants on the primary stability has been a controversial issue for many years.[12] This is supported by the research of Wentaschek et al.[16] who reported that there were two inclined 14 × 4 implants that were not osseointegrated with the value of the implant stability quotient (ISQ) 48. The study of Malo et al.[17] also reported the failure of implants in the posterior region with a size of 3.75 × 15 mm because of inadequate initial stability of low bone quality. Another study conducted by Barikani et al.[18] found that primary stability of the implant increased when longer implants were utilized in poor bone density. Meanwhile, according to Barikani et al.,[19] the primary stability by RFA resulted in higher ISQ values in implants with wider diameters. The study of Carrascal et al.[20] showed that the implant diameter was not significant to the primary stability.
The aim of this study was to determine the effect of implant length and diameter on the primary stability of tilted implants on D4 bone density. The null hypothesis in this study was that the longer and wider the diameter of the implant in the tilted position, the greater the primary implant stability in D4 bone.
| Materials and Methods | | |
This research was conducted in vitro using one type of Superline Dentium implant (Dentium Co. Ltd., Korea) with different lengths (12 and 14 mm), diameters (4 and 5 mm), and inclinations (0°, 15°, 30°, and 45°) of the implant [Figure 1]. A presented, true experimental study design with 16 groups of implants with repeated three times (based on Federer’s formula) was prepared and investigated during September–December 2021 at the Prosthodontic Laboratory of the Faculty of Dentistry, Padjadjaran University, Indonesia. The research carried out consists of group A, which was an implant with length 12 mm and diameter 4 mm; group B, which was an implant with length 14 mm and diameter 4 mm; group C, which was an implant with length 12 mm and diameter 5 mm; and group D, which was an implant with length 14 mm and diameter 5 mm.
The inclusion criteria included implants inserted with the preparation technique as described in manufacturer’s instruction and with the primary stability measurement following manufacturer’s instruction. The exclusion criteria included implants inserted with preparation technique without following manufacturer’s instruction; implants inserted without surgical guide, loose to polyurethane (PU) bone block; and the primary stability measurement without following manufacturer’s instruction.
Each implant group was attached with a surgical guide to an artificial bone block made of PU 20 per cubic foot (PCF) or 0.32 g/cm3 with a size of 180 × 130 × 40 mm3 (#1522-03, SawBones, Pacific Research Laboratories Inc, Vashon, WA, USA) by drawing lines to obtain implant preparation point with a size of 20 × 20 × 40 mm3 [Figure 2]. Surgical guide was made of 3D printed resin material (Resin Merk Phrozen Aquagrey 4k, China) with an inclination of 0°, 15°, 30°, and 45° screwed to the block [Figure 3]. After the surgical guide was installed, the preparation of bone block for the implant groups A and B with an inclination of 0°, 15°, 30°, and 45° was initiated with a guide drill at 2.2 diameter under a speed of 1000 rpm/35 Ncm, a guide drill at 2.6 and 3.6, and a final drill at 4.0 diameter under a speed of 800 rpm/35 Ncm. The preparation of bone block for the implant groups C and D with an inclination of 0°, 15°, 30°, and 45° was performed using a guide drill at 2.2 diameter under a speed of 1000 rpm/35 Ncm, guide drill at 2.6, 3.6, 4.0, and 4.5, and a final drill at 5.0 diameter under a speed of 800 rpm/35 Ncm. Each implant group was inserted with a torque of 35 Ncm and a speed of 20 rpm using a contra-angle handpiece and continued with a rachet. A Smartpeg type 7 device (Dentium Co. Ltd., Korea) was attached to the implant fixture. The Osstell (Osstell mentor; Integration Diagnostics AB, Sweden) probe transducer was aimed at a small magnet at a distance of 2–3 mm, approximately 45° from the top of the Smartpeg and held steady until the instrument beeps to show the ISQ value [Figure 4]. The procedure was repeated three times on each type of implant with four different orientations with an angle of 90° or from the buccal, lingual, mesial, and distal directions. ISQ value > 70 indicates high stability, ISQ 60–69 indicates moderate stability, and ISQ < 60 indicates low stability based on Osstell’s recommendation. Values were averaged and calculated for statistical analysis. | Figure 2: Artificial bone block from polyurethane 20 per cubic foot (SawBones, Pacific Research Laboratories Inc., Vashon, WA, USA)
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 | Figure 4: Measurement of primary stability with the Osstell (mentor; Integration Diagnostics AB, Sweden) tool
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Statistic analysis
Data were analyzed using SPSS, 19th version (SPSS Inc., Chicago, IL, USA). Normal distribution analysis was performed to determine the type of analysis to be applied for the entered data. Univariate analysis of variance (ANOVA) was the statistical formula used to calculate any differences in the primary stability values of each group. Post hoc test was further utilized as a t-test to compare each group, which showed good scores for the primary stability. Statistical significance was defined at P < 0.05.
| Results | | |
The mean value for the primary stability of dental implants with different lengths and diameters in the tilted position is presented in [Table 1]. The highest mean value of the primary stability results for implants with a length of 14 mm and a diameter of 5 mm at 45° inclination shows average ISQ of 72.25. The average value of the lowest primary stability results for implants with a length of 12 mm and a diameter of 4 mm at a slope of 15° has an average ISQ of 63.58. Based on the analysis of ANOVA, P value is less than 0.05 (0.000 … 000244), which indicates a significant difference between the mean value of the 16 groups. | Table 1: The results of the Superline implant average stability measurement with different implant lengths and diameters at tilted implant
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Based on the post hoc follow-up test, the result from each group of implants with different lengths and the same diameter at the tilted position has an average difference with P < 0.05 [Table 2]. Meanwhile, the group of implants with the same length and different diameter at the tilted position also showed a very significant test result, where P < 0.05, that there was a difference [Table 3]. However, the results for groups of implants with different lengths and diameters showed no significant difference (P > 0.005), indicating that an increase on the size of implant, both length and diameter, will produce the same primary stability. | Table 2: Statistical results for the post hoc test of implants in different lengths and the same diameter at tilted position
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 | Table 3: Statistical results of the post hoc test for implants in the same length and different diameter at tilted position
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A comparison of the primary ISQ value at 0°, 15°, 30°, and 45° inclination degrees in each implant group showed had a high stability value at 45° position compared to implants with an inclination of 15° and 30° and also the same stability value as the upright implant (0°). The results can be seen in [Figure 5]. | Figure 5: The mean value of the primary stability from each implant group
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| Discussion | | |
The tilted implant concept was first described by Paulo Maolo in his state-of-art All-on-4 concept, where this technique involves the use of two upright implants in the anterior and two tilted implants in the posterior to support the denture structure.[7] The biomechanical basis of using tilted implants is to place the implant portion to reach into the anterior bone with a higher density and to reduce the distal cantilever of the prosthesis so as to produce a good load distribution and the primary stability of the implant.[7],[9],[21] Tilted implants are recommended for the rehabilitation of complete edentulous of the maxillary that experiences severe resorption, minimization of the need of bone augmentation procedures, and the involvement of vital anatomical structures.[7],[8],[22],[23] This is supported by a study by Pozzi et al.[24] in which 42 tilted implants with a minimal invasive treatment of the atropic posterior maxilla achieved a 96.3% success rate in a median long-term follow-up of 3 years.
Tilted implants are also allowed for immediate loading and the fabrication of implant-supported restorations.[9]One of the requirements for tilted implants in the case of all on four requires good primary stability.[25] Primary stability of the implant is the most important clinical goal that must be achieved at the time of implant placement and becomes a factor for a successful osseointegration of dental implants.[12],[26],[27],[28] Parameters that can affect the primary stability of implants were implant design, surgical technique, and bone quality.[26] The RFA method is used to detect micromovements associated with an increase or decrease in the degree of osseointegration.[11],[29] This study used the Osstell tool (Osstell™ Mentor; Integration Diagnostics AB, Sweden) to measure the primary stability of tilted implants, where the mean of each implant group resulted in an average primary stability value of greater than 60 ISQ. This is clinically the value of the primary stability in each implant group can be said to achieve adequate implant stability.[30]
The primary stability test used a bone block model made of PU, which has homogeneous characteristics and has been considered an ideal material complied with the American Standard Testing and Material (ASTM) F1839-08. This material can be used in different densities to simulate bone in in vitro studies and can be used as a standard material for simulating mechanical tests on orthopedic implants.[31],[32] Human jaw bone quality can be measured using the average bone mineral density (BMD). The BMD value in the maxillary posterior region by dual-energy x-ray absorptiometry in 40 toothless patients was 0.31 ± 0.14 g/cm3.[33] The study by Comuzzi et al.[34] reported in humans BMD mean of maxillary posterior 0.32 g/cm3 equivalent to the PU 20 PCF model. In accordance with these studies, this study used a PU model with a homogeneous density of 0.32 g/cm3 (20 PCF).
Implant length
In relation to the length of the implant to the tilted position, the results of this study showed that implants with a length of 14 mm had a higher primary stability value than implants with a length of 12 mm. This is in accordance with the research of Bataineh and Al-Dakes,[35] which showed that implants with a length of 15 mm had a higher primary stability value than implants with a length of 8 mm and 13 mm. The study of Barikani et al.[18] also showed that implants measured at 13 mm length had a higher ISQ value than implants with a length of 10 mm in low-density bone. Increasing the length of dental implants is thought to play a fundamental role in increasing the primary stability of dental implants.[36] Longer implant will increase the contact area between the bone and the implant and can increase the crown-to-implant ratio.[17],[36]
Implant diameter
In relation to the diameter of the implant to the tilted position, the results of this study indicate that an implant with a diameter of 5 mm has a higher primary stability value than an implant with a diameter of 4 mm. This is in accordance with the study of Barikani et al.[18] who reported that implants with a wider diameter produced good stability values compared to narrow implants. On the other hand, Barikani et al.’s[19] study compared implants with diameters of 3.75 mm, 4 mm, and 5 mm, whereas implants with a diameter of 5 mm had high primary stability values. This shows that the wider the diameter of the implant will increase the surface area and compensate for the excessive force factor so as to increase the primary stability.[19],[35]
Implant length and diameter
Other results in this study showed that implants with a length of 14 mm and a diameter of 4 mm compared with implants with a length of 12 mm and a diameter of 5 with respect to the inclined position of the implant demonstrates no significant difference. This is supported by Sabeva’s research[37] that there is no significant difference in the primary stability of implants with a larger diameter of 0.7 mm and implants 2 mm longer with a smaller diameter. The study of Gomez-Polo et al.[38] also reported similar primary stability results when comparing implants with different diameters and length at 1.5 mm difference. Therefore, most of the data from the literature indicate that both length and diameter can affect the primary stability of implants. However, it depends on how much the length and diameter of the implant are increased.[37]
Degree of inclination implant
The present study showed that implants with an inclination of 45° had higher primary stability values compared with inclinations of 15° and 30° and were equivalent to implants that were upright (0°). This is because the value of the primary stability on tilted implants is influenced by the depth of the implant.[39] In the study of Siqueira et al.,[40] it was mentioned that inserting the implant at 1–2 mm in the direction of the subcrestal position resulted in the ISQ of the implant, which is more stable. These results are also consistent with the study of Chun et al.,[39] which reported that the stability value of tilted implants with a subcrestal depth was better than supracrestal, and there was no difference between tilted implants and upright implants. In addition, implant depth is also related to implant contact with bone to the primary stability.[41] This is supported by the study of Degidi et al.,[42] which showed that implants with a subcrestal depth 1 mm had a bone implant constant (BIC) value of 51.2%, a subcrestal depth 1.5 had a BIC value of 55.1%, and a subcrestal depth 2 mm had a BIC value 65%. However, at a subcrestal implant depth of 3 mm, the BIC value decreased by about 55%. Therefore, the higher the implant–bone contact value, the greater the primary stability of the implant.[41]
Surgical guide computer-aided design (CAD)/computer-aided manufacturing (CAM) in this study was chosen because it offers many advantages, namely, a virtual three-dimensional view of bone morphology, which allows the operator to visualize the surgical bone location prior to implant placement, risks such as inadequate bone support or compromise of important anatomical structures is avoided, combined prosthetic planning allows the treatment to be optimized from a prosthodontic and biomechanical aspect especially in the case of tilted implants with a certain angle as in this study.[21],[43]
This research has several limitations. First, artificial bone was chosen for the experiment in this study because human jaw bones with consistent bone quality were difficult to obtain. Second, each group used one implanted fixture that was simulated in this study. Third, the heating effect during drilling or implant placement was neglected because of the use of artificial bone in this study. Fourth, there is a lack of data regarding the primary stability of tilted implants.
| Conclusion | | |
Based on the limitations of the current in vitro study, it can be concluded that implant length and diameter can significantly affect the primary stability in low-density bone. The longer and wider the size of the dental implant may increase the value of the primary stability, especially in D4 bone density.
Acknowledgements
We acknowledge Dr. Dudi Aripin, Drg., Sp. KG(K), Dean of Faculty of Dentistry, Padjadjaran University, for his support throughout the study. We would like to thank Dr. H. Bernik Maskun from the Faculty of Mathematics and Natural Sciences, Padjadjaran University.
Financial support and sponsorship
This study was self‑funded by the authors.
Conflict of interest
There are no conflicts of interest in this study.
Authors’ contributions
All authors contributed in data collection, data acquisition and analysis, data interpretation, manuscript writing.
Ethical policy and institutional review board statement
Not applicable.
Patient declaration of consent
Not applicable.
Data availability statement
The data set used in the current study is available (option as appropriate): (a) repository name, (b) name of the public domain resources, (c) data availability within the article or its supplementary material, and (d) available on request from contact name/email id, and (e) dataset can be made available after embargo period due to commercial restriction.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3]
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