Fig. 6. Comparison between short and high collar length (A and B)
Fig. 6. Comparison between short and high collar length (A and B)
Fig. 5. Mean rate ± SD of removal torque loss (%) between groups and results of ANOVA test for loss ratio of removal torque value between groups
Fig. 5. Mean rate ± SD of removal torque loss (%) between groups and results of ANOVA test for loss ratio of removal torque value between groups
Fig. 4. Application of cyclic loading with universal testing machine
Fig. 4. Application of cyclic loading with universal testing machine
Fig. 3. 3D scanning for abutment and designing for metal tube
Fig. 3. 3D scanning for abutment and designing for metal tube
Fig. 2. a Stainless steel split cylindrical mold with implant fixture screwed to abutment. b Implant fixture unscrewed from abutment after polymerization. c Implant fixture centralized vertically and perpendicular to the base with platform flushed with resin block level
Fig. 2. a Stainless steel split cylindrical mold with implant fixture screwed to abutment. b Implant fixture unscrewed from ...
Fig. 1. Different abutment angulations and collar lengths
Fig. 1. Different abutment angulations and collar lengths
N
Groups
Subgroups
Initial RTV
Postload RTV
Initial RTL
Postload RTL
...
Collar length
Subgroups
T test
A (2 mm collar length)
B (4 mm collar length)
t
P value
Initial RTV
...
Initial RTV
Postload RTV
Difference between initial and postload RTV
Mean ± SD
Subgroups
GIA
...
%initial RTL
%postload RTL
%difference between initial and postload RTL
Mean ± SD
Subgroups
GIA
...
El-Sheikh, M.A.Y., Mostafa, T.M.N. & El-Sheikh, M.M. Effect of different angulations and collar lengths of conical hybrid implant abutment on screw loosening after dynamic cyclic loading.
Int J Implant Dent 4, 39 (2018). https://doi.org/10.1186/s40729-018-0149-z
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Received: 07 May 2018
Accepted: 11 October 2018
Published: 03 December 2018
DOI: https://doi....
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Prosthodontic Department, Faculty of Dentistry, Tanta University, Elgeish St., Tanta, Egypt
Mai Ahmed Yousry El-Sheikh, Tamer Mohamed Nasr Mostafa & Mohamed Maamoun El-Sheikh
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Within the limitations of this in vitro study, it can be concluded that:
Screw loosening increases with increasing abutment angulation and collar length after 100,000 cycles of dynamic cyclic loading.
Results of this study showed that conical hybrid connection design provides more biomechanically stable screw joint with straight abutments than angled abutments.
Several studies have been conducted on this type of implant–abutment connection [23, 34]. Sutter et al. [35] demonstrated reverse torque values of this hybrid implant–abutment connection that were 124% of the initial tightening torque. These authors suggested that cold welding occurred in the conical hybrid implant–abutment connection.
Schmitt et al. [36] compared conical and nonconical imp...
The increase in RTL with increasing abutment angulation can be attributed to the off-axis force as loading on angled abutments is mostly off-axis, which raises the concern of how angled abutments generally perform with such an unfavorable loading regimen [28]. Forces applied off-axis may be expected to overload the bone surrounding single-tooth implants, as shown by means of finite element analysi...
In the current study, the results showed that there is a significant difference in %RTL before and after application of dynamic cyclic loading for all angulations and collar lengths. These results are in an agreement with previous researches that found a significant difference between %initial and %postload RTL after mechanical cyclic loading [24, 25]. This result was explained by Bickford et al. ...
Conical hybrid connection was used in this study as it was proven that the conical hybrid demonstrated the best stress distribution [20]. This connection has a conical union between the implant fixture and the abutment. In the conical abutment, lateral force is resisted by the taper design of the Morse taper connection. Thus, the stress concentration is resisted by the side-wall contact surface of...
One-way ANOVA and pair-wise Tukey’s post hoc tests showed that %initial RTL among the groups was not significantly different (P > .05), while %postload RTL was significantly different among the three groups (P
Removal torque loss ratio before loading (%initial RTL)
Removal torque loss ratio after loading (%postload RTL)
Removal torque loss ratio between before and after loading (%difference between initial and postload RTL)
Student T test and ANOVA were used to compare mean of %initial and %postload RTL between different groups and subgroups followed by pair-wise Tukey’s post hoc tests at 0.05 leve...
Self-adhesive resin cement (G- CEM, USA) was used for fixing of metal tube to the abutment. A customized rigid metal mounting jig was designed, as a holding device, to ensure solid fixation of the sample while recording the measures.
Abutment screws were tightened in all the groups to 30 Ncm using a digital torque gauge (HTG2 - 200Nc, IMADA, Toyohashi, Japan) according to the manufacturer’s re...
Total 90 stock titanium abutments (Anyridges; MEGAGEN, Seoul, Korea) with different angulations and collar lengths were used in this study and divided into three groups, 30 each according to the degree of abutment angulations GI 0° abutment, GII 15° abutment, and GIII 25°. Each group was divided into two subgroups, 15 each according to implant abutment collar lengths: subgroup A (2 mm) and sub...
To date, there are limited publications regarding the investigation of screw loosening according to abutment angulations and collar lengths before and after dynamic cyclic loading. Sethi and colleagues [19] noted no implant fractures or screw loosening during a 96-month monitoring period for 2261 implants (N = 467 patients) with angulations ranging from 0 to 45°. While Asvanund and colleagues...
Collar length is the distance between the implant platform and the gingival margin. Sometimes, significant vertical space that has not been corrected with vertical ridge augmentation may necessitate selection of longer abutments, which would lead to an increased vertical cantilever. Furthermore, selection of the length of abutment collar would be affected if different distances between the implant...
When the implant set is submitted to functional loads, occlusal forces to the connection are concentrated at the abutment screw; consequently, the optimum preload is critical for joint stability and to avoid screw loosening [7].
Several factors related to screw design and fabrication can affect the risk of abutment or prosthetic screw loosening in a metal-to-metal screw system; these primarily ar...
Successful implant therapy requires a dynamic equilibrium between biological and mechanical factors. The mechanical factors are generally considered multifactorial which are involved in the success of implant rehabilitation. Majority of implant complications nowadays are caused by mechanical factors rather than the implant itself. Mechanical complications of the implant-prosthetic system include l...
The purpose of this in vitro study was to evaluate the effect of different angulations and collar lengths of the implant abutment on screw loosening by measuring removal torque value (RTV) before and after dynamic cyclic loading using digital torque gauge.
A total 90 sets of 4.5 mm diameter × 10 mm length bone level implants with conical hybrid connection were used. They were divided equally...