scholarly journals An evaluation of insertion sites for mini-implants

2012 ◽  
Vol 83 (2) ◽  
pp. 222-229 ◽  
Author(s):  
Morten G. Laursen ◽  
Birte Melsen ◽  
Paolo M. Cattaneo
Keyword(s):  
Maxillary Sinus ◽  
Cortical Bone ◽  
Cortical Thickness ◽  
Anterior Region ◽  
Lateral Region ◽  
Insertion Angle ◽  
Mini Implants ◽  
Bone To Implant Contact ◽  
Insertion Sites ◽  
The Impact

ABSTRACT Objective: (1) To report the thickness of the cortical bone in insertion sites commonly used for orthodontic mini-implants, (2) to assess the impact of a change in insertion angle on primary cortical bone-to-implant contact, and (3) to evaluate the risk of maxillary sinus perforation. Materials and Methods: At autopsy, 27 human samples containing three to five adjacent teeth were excised and scanned using a table-top micro-computed tomography system. Bone thickness measurements were taken at 45° and 90° to the long the axis of the adjacent teeth, simulating a mini-implant insertion at the mid-root level. Results: In the maxilla, the overall mean cortical thickness at 90° was 0.7 mm buccally in the lateral region, 1.0 mm buccally in the anterior region, and 1.3 mm palatally. In the mandible, the mean cortical thickness was 0.7 mm buccally and 1.8 mm lingually in the anterior region; 1.9 mm buccally and 2.6 mm lingually in the lateral region. Changing the insertion angle from 90° to 45° increased the cortical bone-to-implant contact by an average of 47%. Perpendicular insertion at the mid-root level only rarely interfered with the sinus, whereas apically inclined insertion increased the risk of sinus perforation. Conclusions: Buccally and palatally in the maxilla and buccally in the anterior mandible, the thickness of the alveolar cortical bone is often less than 1 mm. In contrast, the alveolar cortical bone is frequently thicker than 2 mm laterally in the mandible. Changing the insertion angle to 45° will generally enhance implant stability but increase the risk of perforation to the maxillary sinus.

Nonlinear Inversion of Ultrasonic Guided Waves for in Vivo Evaluation of Cortical Bone Properties

2021 ◽  
Author(s):  
Xiaojun Song ◽  
Tiandi Fan ◽  
Jundong Zeng ◽  
QinZhen Shi ◽  
Qiong Huang ◽  
...  
Keyword(s):  
Soft Tissue ◽  
Cortical Bone ◽  
Cortical Thickness ◽  
Guided Waves ◽  
Transverse Velocity ◽  
Ultrasonic Guided Waves ◽  
Bulk Wave ◽  
True Value ◽  
The Impact

Abstract Ultrasonic guided waves (UGW), which propagate throughout the whole thickness of cortical bone, are attractive in the early diagnosis of osteoporosis. However, it is challenging due to the impact of soft tissue and the inherent difficulties related to the multiparametric inversion of cortical bone quality factors, such as cortical thickness and bulk wave velocities. Therefore, an UGW based multiple-parameter inversion algorithm is developed to predict strength-related factors in this research. In simulation, a free plate (cortical bone) and a bilayer plate (soft tissue and cortical bone) are used to validate the proposed method. The inverted cortical thickness (CTh), longitudinal velocity (V L ) and transverse velocity (V T ) are in accordance with the true value. Then four bovine cortical bone plates are used in the in vitro experiments. Compared with the reference values, the relative errors for cortical thicknesses are 3.96%, 0.83%, 2.87% and 4.25% respectively. In the in vivo measurements, ultrasonic guided waves are collected from ten volunteers’ tibia. The theoretical dispersion curves depicted by the estimated parameters (V T , V L , CTh) match well with the extracted experimental ones. In comparison to the dual-energy x-ray absorptiometry (DXA), the results show that the estimated transverse velocity and cortical thickness are highly sensitive to the osteoporosis. Therefore, these two parameters (CTh and V T ) of long bones have potential to diagnose bone status in clinical applications.

scholarly journals Insertion Angle Impact on Primary Stability of Orthodontic Mini-Implants

2008 ◽  
Vol 78 (6) ◽  
pp. 1065-1070 ◽  
Author(s):  
Benedict Wilmes ◽  
Yu-Yu Su ◽  
Dieter Drescher
Keyword(s):  
Bone Quality ◽  
Primary Stability ◽  
Insertion Torque ◽  
Insertion Angle ◽  
Oblique Direction ◽  
Mini Implants ◽  
Local Bone ◽  
Torque Values ◽  
The Impact ◽  
Root Contact

Abstract Objective: To analyze the impact of the insertion angle on the primary stability of mini-implants. Materials and Methods: A total of 28 ilium bone segments of pigs were embedded in resin. Two different mini-implant sizes (Dual-Top Screw 1.6 × 8 mm and 2.0 × 10 mm) were inserted at seven different angles (30°, 40°, 50°, 60°, 70°, 80°, and 90°). The insertion torque was recorded to assess primary stability. In each bone, five Dual-Top Screws were used to compensate for differences in local bone quality. Results: The angle of mini-implant insertion had a significant impact on primary stability. The highest insertion torque values were measured at angles between 60° and 70° (63.8° for Dual-Top 1.6 mm and 66.7° for Dual-Top 2.0 mm). Very oblique insertion angles (30°) resulted in reduced primary stability. Conclusions: To achieve the best primary stability, an insertion angle ranging from 60° to 70° is advisable. If the available space between two adjacent roots is small, a more oblique direction of insertion seems to be favorable to minimize the risk of root contact.

scholarly journals Relationship between the angulation of temporary anchoring devices and their displacement. Experimental study

2021 ◽  
Vol 31 (1) ◽  
pp. 10-18
Author(s):  
AB Piacenza ◽  
◽  
GD Peralta ◽  
MR Rocamundi ◽  
VB Fumero ◽  
...  
Keyword(s):  
Experimental Study ◽  
Cortical Bone ◽  
Opposite Direction ◽  
Insertion Angle ◽  
Mini Implants ◽  
The Stability ◽  
Micro Implants ◽  
The Sacrifice ◽  
Digital Caliper

The purpose of this study is to assess how the insertion angle influence the stability mini-implant when loaded with 200cNe in this study, 2mini-screws were implanted in male rabbits’ (n=25) tibia in a 6weeks interval between the firstone and the second one. The second mini-implants were placed at different angles with respect to the cortical bone: -20° in the direction of the force e (GroupI), perpendicular to the force (GroupII) and 30° in the opposite direction of the force (GroupIII). These experimental implants were immediately loaded (right tibias). The Tad`s on the left tibias were regarded as control. The animals were sacrificed six weeks after the first surgery. Linear distances between the two Tad`s were measured with a digital caliper at the time of placement, and after the sacrifice, then were compared. The displacements were: GroupI, 2.96mm ±1.05; GroupII, 0.27mm ±0.36; and GroupIII, 0.29 mm ±0.26. The controls remained. The values for the micro-implants of GroupI showed statistically significant differences (p≤0.05) compared to GroupsII y III. Based on these data, we can conclude that mini-implants inclined towards the direction of the force applied induce more displacement than the ones placed perpendicular to theforce or in the opposite direction of the force

scholarly journals Impact of Implant Design and Bone Properties on the Primary Stability of Orthodontic Mini-Implants

2021 ◽  
Vol 11 (3) ◽  
pp. 1183
Author(s):  
Lejla Redžepagić-Vražalica ◽  
Elmedin Mešić ◽  
Nedim Pervan ◽  
Vahidin Hadžiabdić ◽  
Muamer Delić ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Primary Stability ◽  
Implant Design ◽  
Bone Thickness ◽  
Cortical Bone Thickness ◽  
Mini Implants ◽  
Pull Out ◽  
Bone Properties ◽  
Pulling Force ◽  
The Impact

This study investigated the correlation between bone characteristics, the design of orthodontic mini-implants, the pull-out force, and primary stability. This experimental in vitro study has examined commercial orthodontic mini-implants of different sizes and designs, produced by two manufacturers: Tomas-pin SD (Dentaurum, Ispringen, Germany) and Perfect Anchor (Hubit, Seoul, Korea). The total number of 40 mini-implants were tested. There are two properties that are common to all tested implants—one is the material of which they are made (titanium alloy Ti-6Al-4V), and the other is the method of their insertion. The main difference between the mini-implants, which is why they have been selected as the subject of research in the first place, is reflected in their geometry or design. Regardless of the type of implant, the average pull-out forces were found to be higher for a cortical bone thickness (CBTC) of 0.62–0.67 mm on average, compared to the CBTC < 0.62 mm, where the measured force averages were found to be lower. The analysis of variance tested the impact of the mini-implant geometry on the pull-out force and proved that there is a statistically significant impact (p < 0.015) of all three analyzed geometric factors on the pull-out force of the implant. The design of the mini-implant affects its primary stability. The design of the mini-implant affects the pulling force. The bone quality at the implant insertion point is important for primary stability; thus, the increase in the cortical bone thickness increases the value of the pulling force significantly.

scholarly journals Insertion angle of orthodontic mini-implants and their biomechanical performance: finite element analysis

2015 ◽  
Vol 44 (5) ◽  
pp. 273-279 ◽  
Author(s):  
Vinícius de Oliveira Rossi Arantes ◽  
Cassia Belloto Corrêa ◽  
Nadia Lunardi ◽  
Rodolfo Jorge Boeck Neto ◽  
Rubens Spin-Neto ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
South Korea ◽  
Cortical Bone ◽  
Elastic Deformation ◽  
Cancellous Bone ◽  
Element Analysis ◽  
Insertion Angle ◽  
Mini Implants ◽  
Resistance To Deformation

AbstractObjectiveThe aim of this study was to assess the stresses and strains generated after the application of two types of forces (traction of 200 gf and torsion of 20 N.cm) in two types of orthodontic mini-implants inserted at different (45° and 90° to the cortical bone) angles.Material and methodthree-dimensional models of two brands of mini-implant (SIN – Sao Paulo, Brazil, and RMO – South Korea) were exported and analyzed by finite element analysis (FEA). Analyses were performed on simulations of cortical bone, cancellous bone and the screw.ResultFEA analysis showed that RMO mini-implants had greater elastic deformation when subjected to tensile and torsional forces when compared with SIN mini-implants. For both trademarks and insertion angles tested, there was greater cortical bone deformation, but with the greatest strain located on the mini-implant. Tension on the mini-implant was located in its transmucosal profile region.ConclusionWhen comparing the two brands of mini-implants by FEA, it is fair to conclude that that the larger number of threads and their greater angle of inclination resulted in less resistance to deformation and induced a higher level of tension in the mini-implant and cortical bone when subjected to forces, especially when inserted at an angle of 45º to the cortical bone.

scholarly journals Influence of the growth pattern on cortical bone thickness and mini-implant stability

2020 ◽  
Vol 25 (6) ◽  
pp. 33-42
Author(s):  
Carolina Carmo de Menezes ◽  
Sérgio Estelita Barros ◽  
Diego Luiz Tonello ◽  
Aron Aliaga-Del Castillo ◽  
Daniela Garib ◽  
...  
Keyword(s):  
Success Rate ◽  
Cortical Bone ◽  
Cortical Thickness ◽  
Growth Pattern ◽  
Alveolar Bone ◽  
Insertion Site ◽  
Bone Thickness ◽  
Cortical Bone Thickness ◽  
Mini Implants ◽  
The Stability

ABSTRACT Introduction: Controversial reports suggest a relationship between growth pattern and cortical alveolar bone thickness, and its effect in the use of mini-implants. Objective: The main purpose of this study was to assess the influence of the growth pattern on the cortical alveolar bone thickness and on the stability and success rate of mini-implants. Methods: Fifty-six mini-implants were inserted in the buccal region of the maxilla of 30 patients. These patients were allocated into two groups, based on their growth pattern (horizontal group [HG] and vertical group [VG]). Cortical thickness was measured using Cone Beam Computed Tomography. Stability of mini-implants, soft tissue in the insertion site, sensitivity during loading and plaque around the mini-implants were evaluated once a month. Intergroup comparisons were performed using t tests, Mann-Whitney tests, and Fisher exact tests. Correlations were evaluated with Pearson’s correlation coefficient. Results: The cortical bone thickness was significantly greater in the HG at the maxillary labial anterior region and at the mandibular buccal posterior and labial anterior regions. There was a significant negative correlation between Frankfort-mandibular plane angle (FMA) and the labial cortical thickness of the maxilla, and with the labial and lingual cortical bone thicknesses of the mandible. No significant intergroup difference was found for mini-implant mobility and success rate. No associated factor influenced stability of the mini-implants. Conclusions: Growth pattern affects the alveolar bone cortical thickness in specific areas of the maxilla and mandible, with horizontal patients presenting greater cortical bone thickness. However, this fact may have no influence on the stability and success rate of mini-implants in the maxillary buccal posterior region.

scholarly journals The cutting behavior of cortical bone in different bone osten cutting angles and depths of cut

2021 ◽  
Author(s):  
Yuanqiang Luo ◽  
Yinghui Ren ◽  
Yang Shu ◽  
Cong Mao ◽  
Zhixiong Zhou ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Cutting Force ◽  
Cortical Bone ◽  
Depth Of Cut ◽  
Cutting Angle ◽  
Small Depth ◽  
Proposed Model ◽  
Cutting Processes ◽  
The Impact ◽  
Cutting Path

Abstract Cortical bones are semi-brittle and anisotropic, this brings the challenge to suppress vibration and avoid undesired fracture in precise cutting processes in surgeries. In this paper, we proposed a novel analytical model to represent cutting processes of cortical bones, and we used to evaluate cutting forces and fracture toughness, and investigate the formations of chips and cracks under varying bone osteon cutting angles and depths. To validate the proposed model, the experiments are conducted on orthogonal cuttings over cortical bones to investigate the impact of bone osteon cutting angle and depth on cutting force, crack initialization and growth, and fracture toughness of cortical bone microstructure. The experimental results highly agreed with the prediction by the proposed model in sense that (1) curly, serrated, grainy and powdery chips were formed when the cutting angle was set as 0°, 60°, 90°, and 120°, respectively. (2) Bone materials were removed dominantly by shearing at a small depth of cut from 10 to 50 µm, and by a mixture of pealing, shearing, and bending at a large depth of cut over 100 µm at different cutting orientations. Moreover, it was found that a cutting path along the direction of crack initialization and propagation benefited to suppress the fluctuation of cutting force thus reduce the vibration. The presented model has theoretical and practical significance in optimizing cutting tools and operational parameters in surgeries.

scholarly journals Bone remodelling patterns around orthodontic mini-implants migrating in bone: an experimental study in rat vertebrae

2021 ◽  
Author(s):  
Kathrin Becker ◽  
Nicole Rauch ◽  
Giulia Brunello ◽  
Sarah Azimi ◽  
Mathias Beller ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Remodelling ◽  
Micro Computed Tomography ◽  
Bone Apposition ◽  
Implant Migration ◽  
Mini Implants ◽  
Quantitative Analyses ◽  
Bone To Implant Contact ◽  
Laser Capture ◽  
Complementary Analysis

Summary Background Orthodontic implant migration has been clinically observed in presence of continuous loading forces. Recent studies indicate that osteocytes play a crucial role in this phenomenon. Objectives Aim of this study was to investigate local osteocytic gene expression, protein expression, and bone micro-structure in peri-implant regions of pressure and tension. Material and methods The present work reports a complementary analysis to a previous micro-computed tomography study. Two customized mini-implants were placed in one caudal rat vertebra and connected by a nickel–titanium contraction spring generating different forces (i.e. 0, 0.5, 1.0, and 1.5 N). Either at 2 or 8 weeks, the vertebrae were harvested and utilized for 1. osteocytic gene expression using laser capture micro-dissection on frozen sections coupled with qPCR, 2. haematoxylin–eosin staining for qualitative and quantitative analyses, 3. immunofluorescence staining and analysis, and 4. bone-to-implant contact on undecalcified samples. Results At the two time points for all the performed analyses no significant differences were observed with respect to the applied force magnitudes and cell harvesting localization. However, descriptive histological analysis revealed remarkable bone remodelling at 2 weeks of loading. At 8 weeks the implants were osseointegrated and, especially in 1.0 and 1.5 N groups, newly formed bone presented a characteristic load bearing architecture with trabecula oriented in the direction of the loading. Conclusions The present study confirmed that stress-induced bone remodelling is the biological mechanism of orthodontic implant migration. Bone apposition was found at ‘tension’ and ‘pressure’ sites thus limiting implant migration over time.

scholarly journals COMPARATIVE ANALYSIS OF MONOCORTICAL AND BICORTICAL METHODS OF INSTALLING MINI-IMPLANTS

2021 ◽  
pp. 38-40
Author(s):  
O.Yu. Rivis ◽  
V.S. Melnyk ◽  
M.V. Rivis ◽  
K.V. Zombor
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comparative Analysis ◽  
Cortical Bone ◽  
Bone Tissue ◽  
Orthodontic Treatment ◽  
The Finite Element Method ◽  
Force Load ◽  
Mini Implants ◽  
Element Method

The aim of the study. Carry out a comparative analysis of the support ability of human jaw bone tissue in monocortical and bicortical installation of a mini-implant of own design OMG. Research methods. In order to study biomechanical characteristics of developed OMG mini-implant and bone tissue capacity during monocortical and bicortical installation, the finite element method (MSE) was used. The scheme and finite element 2-D model of bicortical installation of OMG mini-implant (length 8 mm, diameter 1.8 mm) provided full penetration through one layer of cortical bone equal to 1 mm, the entire cancellous bone and immersion in the second layer of cortical bone by 0, 5 mm. No implantation was immersed in the second cortical layer of bone during monocortical installation. A single force load of 1 N was applied in the horizontal direction parallel to the cortical plate of the bone. Results of the study. One of the most important factors leading to the success of the use of a mini-implant is its stability in the process of orthodontic treatment. Quite a high level of failure in the monocortical installation of mini-screws has led to the search for better methods to ensure the stability of their use. This was a bicortical method of fixation, based on the placement of the minig screw in the thickness of the two cortical plates of the jaws. Area for such installation of mini-screws can be a site of a palate and alveolar sprouts at installation of miniimplants through all its thickness. As shown by our data on the use of the finite element method under the force load of the biomechanical system "bone - mini-implant", the stress concentration zone is located in the area of the cortical bone of the jaw. The results of the calculation of the maximum stresses (σmax, MPa) and the maximum possible displacements (umax, mm) of the mini-implant in the biomechanical system "bone - mini-implant" in monocortical installation were, respectively, 8.27 MPa and 0.300 * 10-8 mm and in bicortical installation 6.00 MPa and 0.201 * 10-8 mm. The bicortical method of fixing the mini-implant in the jaw bones significantly increases the ability to resist deformation of this type of biomechanical system under force loads of the mini-implant. In the bicortical method of mini-implant placement, the extreme values of equivalent according to Mises stresses in the upper part of the cortical bone of the jaw are reduced by 27%. This can be explained by a significant increase in the area of contact due to the two layers of the cortical bone of the jaw with the surface of the mini-implant. Conclusion. The bicortical method of installing mini-implants is a more effective and reliable way to provide skeletal support during orthodontic treatment.

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