Dynamic fatigue performance of implant-abutment assemblies with different tightening torque values

The biomechanical stability of the implant-abutment connection is critical for the success of implant-supported restorations. This study investigated the effect of a positioning index on the abutment screw preload values of tapered connection implants. Twenty Morse taper implants presenting an internal locking hex received 10 solid and 10 straight screw retained abutments for cemented single-crown restorations. Ten abutments had a positioning index to fit the internal locking hex of the implant (straight), and 10 were locked only by the implant taper (solid). The preload values for each abutment screw after a tightening torque were registered by strain gauges. Prosthetic crowns were placed on each abutment and subjected to mechanical cycling. Detorque forces were applied to each abutment and compared with the initial torque values. Data were statistically analyzed using Kolmogorov-Smirnov and Student t tests. The nonindexed group presented higher initial preload (6.05 N ± 0.95 N) compared with the indexed group (4.88 N ± 0.92 N; P < .05). After cycling, the nonindexed group exhibited less reduction of preload (13.84% ± 6.43%) compared with the indexed group (52.65% ± 14.81%; P < .01). Indexed tapered abutments for single-crown restorations might represent greater biomechanical risk under function.

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Effect of Screw Channel Angulation on Reverse Torque Values of Dental Implant Abutment Screws

Journal of Prosthodontics ◽

10.1111/jopr.13111 ◽

2019 ◽

Vol 28 (9) ◽

pp. 969-972

Author(s):

Eric Hu ◽

Anton Petrich ◽

Glen Imamura ◽

Christopher Hamlin

Keyword(s):

Dental Implant ◽

Screw Channel ◽

Reverse Torque ◽

Implant Abutment ◽

Torque Values ◽

Dental Implant Abutment

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Axial Displacements and Removal Torque Changes of Five Different Implant-Abutment Connections under Static Vertical Loading

Materials ◽

10.3390/ma13030699 ◽

2020 ◽

Vol 13 (3) ◽

pp. 699 ◽

Cited By ~ 2

Author(s):

Ki-Seong Kim ◽

Young-Jun Lim

Keyword(s):

Static Loading ◽

Testing Machine ◽

Butt Joint ◽

Removal Torque ◽

Vertical Loading ◽

Implant Abutment ◽

Before And After ◽

Masticatory Force ◽

Torque Values ◽

Molar Region

The aim of this study was to examine the settling of abutments into implants and the removal torque value under static loading. Five different implant-abutment connections were selected (Ext: external butt joint + two-piece abutment; Int-H2: internal hexagon + two-piece abutment; Int-H1: internal hexagon + one-piece abutment; Int-O2: internal octagon + two-piece abutment; Int-O1: internal octagon + one-piece abutment). Ten implant-abutment assemblies were loaded vertically downward with a 700 N load cell at a displacement rate of 1 mm/min in a universal testing machine. The settling of the abutment was obtained from the change in the total length of the entire implant-abutment unit before and after loading using an electronic digital micrometer. The post-loading removal torque value was compared to the initial torque value with a digital torque gauge. The settling values and removal torque values after 700 N static loading were in the following order, respectively: Ext < Int-H1, Int-H2 < Int-O2 < Int-O1 and Int-O2 < Int-H2 < Ext < Int-H1, Int-O1 (α = 0.05). After 700 N vertical static loading, the removal torque values were statistically different from the initial values, and the post-loading values increased in the Int-O1 group and Int-H1 group (α = 0.05) and decreased in the Ext group, Int-H2 group, and Int-O2 group (α = 0.05). On the basis of the results of this study, it should be taken into consideration that a loss of the preload due to the settling effect can lead to screw loosening during a clinical procedure in the molar region where masticatory force is relatively greater.

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Dynamic Characteristics of Plastic Plates With Bolted Joints

Journal of Vibration and Acoustics ◽

10.1115/1.4044865 ◽

2019 ◽

Vol 142 (1) ◽

Author(s):

Akira Saito ◽

Hideyoshi Suzuki

Keyword(s):

Dynamic Characteristics ◽

Vibration Mode ◽

Acrylonitrile Butadiene Styrene ◽

Bolted Joints ◽

Modal Testing ◽

Analytical Models ◽

Plate Motion ◽

Tightening Torque ◽

Modeling Strategy ◽

Torque Values

Abstract This paper discusses the dynamic characteristics of plastic plates with bolted joints. The effects of tightening torque on the modal properties of the plates are investigated. Experimental and numerical modal analyses have been conducted on the plates made of acrylonitrile butadiene styrene (ABS), that are clamped by bolted joints. First, the effect of tightening torque on the vibration mode of the plates is investigated by experimental modal analyses. Modal testing has been conducted for various tightening torque values, and the relationships between the modal parameters and the tightening torques are discussed. Second, the effects of tightening torque on the vibration mode are studied by using analytical models for the bolted joints based on the finite element method (FEM). Based on the comparisons between the experimental and the numerical results, a modeling strategy for the boundary conditions between the plates is introduced and its validity is discussed. From both experimental and numerical studies, it is shown that the natural frequencies of the structures with bolted joints tend to converge to specific values as tightening torque increases. Moreover, it is also shown that when modeling the bolted plates by FEM, the inter-plate motion should be constrained by a boundary condition to properly suppress the out-of-phase motion of the plates.

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In Vitro Evaluation of Manual Torque Values Applied to Implant-Abutment Complex by Different Clinicians and Abutment Screw Loosening

BioMed Research International ◽

10.1155/2017/7376261 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Onur Dincer Kose ◽

Burcin Karataslı ◽

Sabit Demircan ◽

Taha Emre Kose ◽

Erhan Cene ◽

...

Keyword(s):

Dynamic Loading ◽

Optical Microscope ◽

Control Group ◽

Screw Loosening ◽

Loading Test ◽

Torque Wrench ◽

Implant Abutment ◽

Torque Values ◽

Abutment Screw

Preload is applied to screws manually or using a torque wrench in dental implant systems, and the preload applied must be appropriate for the purpose. The aim of this study was to assess screw loosening and bending/torsional moments applied by clinicians of various specialties following application of manual tightening torque to combinations of implants and abutments. Ten-millimeter implants of 3.7 and 4.1 mm diameters and standard or solid abutments were used. Each group contained five implant-abutment combinations. The control and experimental groups comprised 20 and 160 specimens, respectively. Implants in the experimental group were tightened by dentists of different specialties. Torsional and bending moments during tightening were measured using a strain gauge. Control group and implants with preload values close to the ideal preload were subjected to a dynamic loading test at 150 N, 15 Hz, and 85,000 cycles. The implants that deformed in this test were examined using an optical microscope to assess deformities. Manual tightening did not yield the manufacturer-recommended preload values. Dynamic loading testing suggested early screw loosening/fracture in samples with insufficient preload.

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Variation in the total lengths of abutment/implant assemblies generated with a function of applied tightening torque in external and internal implant-abutment connection

Clinical Oral Implants Research ◽

10.1111/j.1600-0501.2010.02063.x ◽

2010 ◽

Vol 22 (8) ◽

pp. 834-839 ◽

Cited By ~ 33

Author(s):

Ki-Seong Kim ◽

Young-Jun Lim ◽

Myung-Joo Kim ◽

Ho-Beom Kwon ◽

Jae-Ho Yang ◽

...

Keyword(s):

Tightening Torque ◽

Implant Abutment

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Dynamic fatigue properties of the dental implant–abutment interface: Joint opening in wide-diameter versus standard-diameter hex-type implants

Journal of Prosthetic Dentistry ◽

10.1067/mpr.2001.115250 ◽

2001 ◽

Vol 85 (6) ◽

pp. 599-607 ◽

Cited By ~ 37

Author(s):

Scott A. Hoyer ◽

Clark M. Stanford ◽

Supanee Buranadham ◽

Todd Fridrich ◽

Jacob Wagner ◽

...

Keyword(s):

Dental Implant ◽

Fatigue Properties ◽

Joint Opening ◽

Wide Diameter ◽

Implant Abutment ◽

Dental Implant Abutment ◽

Dynamic Fatigue

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An Indirect Method to Measure Abutment Screw Preload: A Pilot Study Based on Micro-CT Scanning

Brazilian Dental Journal ◽

10.1590/0103-6440201300274 ◽

2015 ◽

Vol 26 (6) ◽

pp. 596-601 ◽

Cited By ~ 1

Author(s):

Carlos Eduardo E. Rezende ◽

Jason Alan Griggs ◽

Yuanyuan Duan ◽

Amanda M. Mushashe ◽

Gisele Maria Correr Nolasco ◽

...

Keyword(s):

Ct Scanning ◽

Measuring Method ◽

Micro Ct ◽

Ct Scanner ◽

Removal Torque ◽

Ct Technique ◽

Original Length ◽

Implant Abutment ◽

Torque Values ◽

Abutment Screw

This study aimed to measure the preload in different implant platform geometries based on micro-CT images. External hexagon (EH) implants and Morse Tapered (MT) implants (n=5) were used for the preload measurement. The abutment screws were scanned in micro-CT to obtain their virtual models, which were used to record their initial length. The abutments were screwed on the implant with a 20 Ncm torque and the set composed by implant, abutment screw and abutment were taken to the micro-CT scanner to obtain virtual slices of the specimens. These slices allowed the measurement of screw lengths after torque application and based on the screw elongation. Preload values were calculated using the Hooke's Law. The preloads of both groups were compared by independent t-test. Removal torque of each specimen was recorded. To evaluate the accuracy of the micro-CT technique, three rods with known lengths were scanned and the length of their virtual model was measured and compared with the original length. One rod was scanned four times to evaluate the measuring method variation. There was no difference between groups for preload (EH = 461.6 N and MT = 477.4 N), but the EH group showed higher removal torque values (13.8±4.7 against 8.2±3.6 Ncm for MT group). The micro-CT technique showed a variability of 0.053% and repeatability showed an error of 0.23 to 0.28%. Within the limitations of this study, there was no difference between external hexagon and Morse taper for preload. The method using micro-CT may be considered for preload calculation.

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Original vs Non-Original “Cast-To” Gold Abutment-Implant Connection: Analysis of the Internal Fit and Long-Term Fatigue Performance

10.21203/rs.3.rs-42021/v1 ◽

2020 ◽

Author(s):

Raquel Alonso-Pérez ◽

José F. Bartolomé ◽

Cristina Fraile ◽

Guillermo Pradíes

Keyword(s):

Artificial Saliva ◽

Testing Machine ◽

Cyclic Fatigue ◽

Fatigue Performance ◽

Tight Contact ◽

Implant Abutment ◽

Implant System ◽

Internal Fit

Abstract Background: Restoring implants with not original abutment-implant connection are widely used by clinicians. Due to the current scarcity of in-vitro studies about compatible abutments and lack of relevant clinical studies, long-term fatigue performance of non-original abutments should be analyzed. The aim of this research was to assess the internal accuracy and the cyclic fatigue life after artificial aging of three implant-abutment configurations restored with one original and two compatible non-original “cast-to” gold abutments.Materials and Methods: Forty-eight original internal hexagon connection implants were connected to three different brands of abutments (n= 16 each): one original to the implant system and two non-originals. Internal accuracy and the percentage of surface with tight contact were assessed under Scanning Electron Microscope (SEM) in twelve cross-sectioned samples at three different areas (platform, internal and screw). To evaluate the fatigue mechanical behaviour under cyclic load, samples were loaded according to the ISO Norm 14801 in a universal testing machine at 2 Hz in air. Previously, samples were aged by thermocycling with 10,000 cycles at 5 °C and 55 °C in artificial saliva. Results: Original abutments presented the best accuracy and highest percentage of tight contact in the internal areas. Meanwhile, original abutments showed the lower cyclic fatigue strength degradation and the long-term success. Conclusions: Occlusal loads are transferred more homogenously through the system when original abutments are used because the better fit between the different internal components. This fact provides the highest fatigue resistance for all the restorations studied.

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