J Adv Prosthodont.  2016 Oct;8(5):388-395. 10.4047/jap.2016.8.5.388.

Influence of the connection design and titanium grades of the implant complex on resistance under static loading

• Park SJ
• Lee SW
• Leesungbok R
• Ahn SJ

• KMID: 2355443
• DOI: http://doi.org/10.4047/jap.2016.8.5.388

Abstract

PURPOSE
The purpose of this study was to evaluate the resistance to deformation under static overloading by measuring yield and fracture strength, and to analyze the failure characteristics of implant assemblies made of different titanium grades and connections.
MATERIALS AND METHODS
Six groups of implant assemblies were fabricated according to ISO 14801 (n=10). These consisted of the combinations of 3 platform connections (external, internal, and morse tapered) and 2 materials (titanium grade 2 and titanium grade 4). Yield strength and fracture strength were evaluated with a computer-controlled Universal Testing Machine, and failed implant assemblies were classified and analyzed by optical microscopy. The data were analyzed using the One-way analysis of variance (ANOVA) and Student's t-test with the level of significance at P=.05.
RESULTS
The group IT4S had the significantly highest values and group IT2 the lowest, for both yield strength and fracture strength. Groups IT4N and ET4 had similar yield and fracture strengths despite having different connection designs. Group MT2 and group IT2 had significant differences in yield and fracture strength although they were made by the same material as titanium grade 2. The implant system of the similar fixture-abutment interfaces and the same materials showed the similar characteristics of deformation.
CONCLUSION
A longer internal connection and titanium grade 4 of the implant system is advantageous for static overloading condition. However, it is not only the connection design that affects the stability. The strength of the titanium grade as material is also important since it affects the implant stability. When using the implant system made of titanium grade 2, a larger diameter fixture should be selected in order to provide enough strength to withstand overloading.

Keyword

Dental Implant-Abutment Connection; Titanium grade; Yield strength; Static loading; Implant failure

MeSH Terms

Dental Implant-Abutment Design
Microscopy
Titanium*
Titanium

Figure

• 

  Fig. 1 (A) Schematic illustration of the design of the testing apparatus following ISO 14801 (2007). The distance from the center of the hemisphere to the top face of the resin cylinder, representing the bone level, was standardized at 11 mm. The specimens were then clamped in a special jig (machine shop, Hannover Medical School, Hannover, Germany) while ensuring a 30° angle between the implant axis and the direction of force transfer. (B) The set up for mechanical testing, with crowns positioned in a 30° off-axis orientation.

• 

  Fig. 2 Multiple comparisons from the analysis of the mean yield strengths of different types of implants (oneway ANOVA, n = 10). *Significant difference (P < .05). IT4S: Straumann Bone level, IT4D: Dentium superline, IT4N: Neobiotech CMI IS, IT2: Dentsply Xive s, MT2: Ankylos C/X, ET4: Neobiotech CMI EB

• 

  Fig. 3 Multiple comparisons resulting from the analysis of the mean fracture strength of different types of implants (one-way ANOVA, n = 10). *Significant difference (P < .05) IT4S: Straumann Bone level, IT4D: Dentium superline, IT4N: Neobiotech CMI IS, IT2: Dentsply Xive s, MT2: Ankylos C/X, ET4: Neobiotech CMI EB

• 

  Fig. 4 Longitudinal section images of failed systems taken with a digital microscope (×20). (A) IT4S (Straumann Bone level), (B) IT4D (Dentium superline), (C) IT4N (Neobiotech CMI IS), (D) IT2 (Dentsply Xive s), (E) MT2 (Ankylos C/X) (F) ET4 (Neobiotech CMI EB).

• 

  Fig. 5 (A) Bottom view of a failed screw and fixture in group IT2 (×60). Dimples, which are characteristic of ductile failure, can be seen on the surface of the fractured screw. (B) Bottom view of a failed screw and fixture in group IT2 (×60). The black arrow indicates a compression curl, which defines the fracture origin on the opposing tensile side (×100).

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