The Mechanics of Cervical Muscle Recruitment on Cervical Spine Stability —A Biomechanical in Vitro Study using Porcine Model

2008 ◽  
Vol 24 (1) ◽  
pp. 63-68 ◽  
Author(s):  
C.-H. Cheng ◽  
T.-Y. Chen ◽  
Y.-W. Kuo ◽  
J.-L. Wang
Keyword(s):  
Cervical Spine ◽  
Muscle Force ◽  
Sagittal Plane ◽  
In Vitro Study ◽  
Spinal Stability ◽  
Muscle Recruitment ◽  
Spine Stability ◽  
Cervical Muscles ◽  
The Stability

ABSTRACTCervical muscles are crucial in providing the stability of the cervical spine. Many in vitro studies have investigated the relationship between muscle force and stability directly. However, the effects of different muscle dysfunctions or muscle recruitments on cervical spine stability are not yet clear and therefore, worthy of study. A spine testing apparatus with muscle force replication activated by pneumatic cylinders was developed to find the effect of muscles on spinal stability. Seven porcine cervical spines (C2-T1) were used. Three pairs of cervical muscles, including neck flexors (sternocleidomastoid, SCM) and neck extensors (splenius capitis, SPL; semispinalis capitis, SSC), were simulated. The experimental tests included: 1. no muscle recruitment, 2. full muscle recruitments, 3. SCM dysfunction, 4. SPL dysfunction, and 5. SSC dysfunction. The external pure moment in sagittal plane was applied from 0 Nm to 2 Nm to examine the stability/flexibility of specimens. The spinal stability was evaluated by the neutral zone (NZ), the range of motion (ROM), the reduced NZ (R_NZ), and the reduced ROM (R_ROM). Loading responses of C7-T1 disc were also measured. The results of this study showed: The activation of cervical muscles decreased the NZ and ROM. The degree of decrease among different muscle dysfunctions, however, was not significantly different. The SPL dysfunction induced larger anterior shear force, while the SCM dysfunction exclusively induced extension moment. In conclusion, the muscle forces could stabilize the cervical spine, but significant decrease in spinal stability was not found among dysfunctions of different muscles. The SCM and SPL dysfunction may result in abnormal stress at the C7-T1 disc.

scholarly journals Effects of occipital-atlas stabilization in the upper cervical spine kinematics: an in vitro study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
César Hidalgo-García ◽  
Ana I. Lorente ◽  
Carlos López-de-Celis ◽  
Orosia Lucha-López ◽  
Miguel Malo-Urriés ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Sagittal Plane ◽  
Frontal Plane ◽  
In Vitro Study ◽  
Upper Cervical Spine ◽  
Lateral Flexion ◽  
Alar Ligament ◽  
Before And After ◽  
Upper Cervical

AbstractThis study compares upper cervical spine range of motion (ROM) in the three cardinal planes before and after occiput-atlas (C0–C1) stabilization. After the dissection of the superficial structures to the alar ligament and the fixation of C2, ten cryopreserved upper cervical columns were manually mobilized in the three cardinal planes of movement without and with a screw stabilization of C0–C1. Upper cervical ROM and mobilization force were measured using the Vicon motion capture system and a load cell respectively. The ROM without C0–C1 stabilization was 19.8° ± 5.2° in flexion and 14.3° ± 7.7° in extension. With stabilization, the ROM was 11.5° ± 4.3° and 6.6° ± 3.5°, respectively. The ROM without C0–C1 stabilization was 4.7° ± 2.3° in right lateral flexion and 5.6° ± 3.2° in left lateral flexion. With stabilization, the ROM was 2.3° ± 1.4° and 2.3° ± 1.2°, respectively. The ROM without C0–C1 stabilization was 33.9° ± 6.7° in right rotation and 28.0° ± 6.9° in left rotation. With stabilization, the ROM was 28.5° ± 7.0° and 23.7° ± 8.5° respectively. Stabilization of C0–C1 reduced the upper cervical ROM by 46.9% in the sagittal plane, 55.3% in the frontal plane, and 15.6% in the transverse plane. Also, the resistance to movement during upper cervical mobilization increased following C0–C1 stabilization.

Reverse torque values of abutment screws after dynamic loading: The effects of sealant agents and the taper of conical connections

2020 ◽  
Author(s):  
Arda Ozdiler ◽  
suleyman dayan ◽  
Burc Gencel ◽  
Gulbahar Isık-Ozkol
Keyword(s):  
Dynamic Loading ◽  
Antibacterial Agent ◽  
In Vitro Study ◽  
Control Group ◽  
Silicone Sealant ◽  
Reverse Torque ◽  
The Stability ◽  
Torque Values ◽  
Chlorhexidine Gel

This in vitro study evaluated the influence of taper angles on the internal conical connections of implant systems and of the application of chlorhexidine gel as an antibacterial agent or a polyvinyl siloxane (PVS) sealant on the reverse torque values of abutment screws after dynamic loading. The current study tested four implant systems with different taper angles (5.4°, 12°, 45°, and 60°). Specimens were divided into three groups: control (neither chlorhexidine gel filled nor silicone sealed), 2% chlorhexidine gel-filled or silicone-sealed group, and group subjected to a dynamic load of 50 N at 1 Hz for 500,000 cycles prior to reverse torque measurements. Quantitative positive correlation was observed between the taper angle degree and the percentage of tightening torque loss. However, this correlation was significant only for the 60° connection groups except in the group in which a sealant was applied ( p = 0.013 for the control group, p = 0.007 for the chlorhexidine group). Percentages of decrease in the torque values of the specimens with silicone sealant application were significantly higher compared with both the control and chlorhexidine groups ( p = 0.001, p = 0.002, p = 0.001, and p = 0.002, respectively, according to the increasing taper angles); the percentage of decrease in torque values due to chlorhexidine application was statistically insignificant when compared with the control group. The application of gel-form chlorhexidine as an antibacterial agent does not significantly affect the stability of the implant–abutment connection under dynamic loads. PVS sealants may cause screw loosening under functional loads.

scholarly journals Influence of Orthodontic Anchor Screw Anchorage Method on the Stability of Artificial Bone: An In Vitro Study

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3205 ◽  
Author(s):  
Seen-Young Kang ◽  
Ji-Min Yu ◽  
Hyoung-Sik Kim ◽  
Jun-Seok Lee ◽  
Chan-Mi Yeon ◽  
...  
Keyword(s):  
In Vitro Study ◽  
Automatic Device ◽  
Insertion Torque ◽  
Artificial Bone ◽  
Artificial Bones ◽  
Significant Difference ◽  
The Mean ◽  
The Stability ◽  
Torque Values

This study aims to compare the torque values for various lengths of the titanium-based orthodontic anchor screw (OAS), different anchorage methods and varying artificial bone densities after predrilling. Furthermore, the effects of these parameters on bone stability are evaluated. A total of 144 OASs were prepared with a diameter of 1.6 mm and heights of 6, 8 and 10 mm. Artificial bones were selected according to their density, corresponding to Grades 50, 40 and 30. Torque values for the automatic device and manual anchorage methods exhibited a statistically significant difference for the same-sized OAS, according to the bone density of the artificial bones (p < 0.05). However, when insertion torque was at the maximum rotations, there was no significant difference in the torque values for the Grade 30 artificial bone (p > 0.05). When the torque values of both anchorage methods were statistically compared with the mean difference for each group, the results of the manual anchorage method were significantly higher than those of the automatic device anchorage method (p < 0.05). A statistically significant difference was observed in the bone stability resulting from different OAS anchorage methods and artificial bone lengths. These findings suggest that the automatic anchorage method should be used when fixing the OAS.

scholarly journals The Stability of Temporary Restorations Fabricated on a Healing Cap for Immediate Loading: An In Vitro Study

2018 ◽  
Vol 8 (11) ◽  
pp. 2261
Author(s):  
Sangho Jun ◽  
Hyonseok Jang ◽  
Enji Cheon ◽  
MinJu Kim ◽  
Sungwon Ju ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Load Distribution ◽  
In Vitro Study ◽  
Bite Force ◽  
Immediate Loading ◽  
Pull Out ◽  
The Stability ◽  
Implant Treatment ◽  
Pull Out Strength

The aim of this study was to analyze the load distribution of interim restorations using healing cap during immediate loading implant treatment in vitro. A total of 29 models with interim restorations which were fabricated with healing cap were selected. The pull-out strength was measured with a used healing cap and new healing cap. The compressive strength and sinking distance were also measured. The pull-out strength of interim restoration showed lower value (max. 29.8 N) compared to the natural bite force. The sinking amounts were larger than normal tooth sinking. The sinking amounts of interim restorations fabricated on a healing cap were roughly 3 times (0.3–0.5 mm under 450 N) those of normal teeth. The interim restoration on plastic healing cap would be useful for immediate loading implant treatment.

scholarly journals Development of a System for In Vitro Neck Muscle Force Replication in Whole Cervical Spine Experiments

Spine ◽  
2001 ◽  
Vol 26 (20) ◽  
pp. 2214-2219 ◽  
Author(s):  
Manohar M. Panjabi ◽  
Takehiko Miura ◽  
Peter A. Cripton ◽  
Jaw-Lin Wang ◽  
Amrinder S. Nain ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Muscle Force ◽  
Neck Muscle

scholarly journals Upper Cervical Spine Stability: Maximum Rotation and the Rotation Stress Test in Clinics

2019 ◽  
Vol 7 ◽  
Author(s):  
Ana I Lorente ◽  
Mario Maza Frechín ◽  
Albert Pérez Bellmunt ◽  
César Hidalgo García
Keyword(s):  
Cervical Spine ◽  
Stress Test ◽  
Craniocervical Junction ◽  
Upper Cervical Spine ◽  
Spine Stability ◽  
Upper Cervical ◽  
Rotation Stress

The rotation stress test is used to evaluate stability of the craniocervical junction by assuming that it gives the maximum rotation. However, a more complex manipulation might show a higher rotation: the rotation with extension and contralateral bending. This was tested in vitro with ten upper cervical spine specimens.

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