J Adv Prosthodont.  2015 Apr;7(2):160-165. 10.4047/jap.2015.7.2.160.

In-vitro development of a temporal abutment screw to protect osseointegration in immediate loaded implants

• Garcia-Roncero H
• Caballe-Serrano J
• Cano-Batalla J
• Cabratosa-Termes J
• Figueras-Alvarez O

• KMID: 2118247
• DOI: http://doi.org/10.4047/jap.2015.7.2.160

Abstract

PURPOSE
In this study, a temporal abutment fixation screw, designed to fracture in a controlled way upon application of an occlusal force sufficient to produce critical micromotion was developed. The purpose of the screw was to protect the osseointegration of immediate loaded single implants.
MATERIALS AND METHODS
Seven different screw prototypes were examined by fixing titanium abutments to 112 Mozo-Grau external hexagon implants (MG Osseous(R); Mozo-Grau, S.A., Valladolid, Spain). Fracture strength was tested at 30degrees in two subgroups per screw: one under dynamic loading and the other without prior dynamic loading. Dynamic loading was performed in a single-axis chewing simulator using 150,000 load cycles at 50 N. After normal distribution of obtained data was verified by Kolmogorov-Smirnov test, fracture resistance between samples submitted and not submitted to dynamic loading was compared by the use of Student's t-test. Comparison of fracture resistance among different screw designs was performed by the use of one-way analysis of variance. Confidence interval was set at 95%.
RESULTS
Fractures occurred in all screws, allowing easy retrieval. Screw Prototypes 2, 5 and 6 failed during dynamic loading and exhibited statistically significant differences from the other prototypes.
CONCLUSION
Prototypes 2, 5 and 6 may offer a useful protective mechanism during occlusal overload in immediate loaded implants.

Keyword

Dental implant-abutment; Single-tooth dental implant; Immediate dental implant loading

MeSH Terms

Bite Force
Dental Implants, Single-Tooth
Immediate Dental Implant Loading
Mastication
Osseointegration*
Titanium
Titanium

Figure

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  Fig. 1 Schematic diagram of the screwdriver/implant/prosthesis (A) control screw in the abutment. (B) Prototype 1 screw in the abutment. (C) Prototype 2, 3, 4, 5 and 6 screw in the abutment.

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  Fig. 2 Schematic diagram of the prototype 1 screw (A) and prototype 2, 3, 4, 5 and 6 (B). ST= Shank thickness. HST= Thickness of head shank union.

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  Fig. 3 Schematic diagram of the prototype 2, 3, 4, 5 and 6. Prototypes differed in thickness at the level of the head shank union (HST).

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  Fig. 4 Mechanical testing setup with implants positioned in a 30° off-axis orientation.

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  Fig. 5 Box-and-whisker plot of fracture resistance for the seven types of screw without previous cyclic loading. The dot denotes the mean. Response is shown in Ncm.

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  Fig. 6 Details of prototype screw design. (A) Control screw fragment after fracture. (B) Prototype 5 screw fragment after fracture. (C) A 1.25 mm screwdriver inserted into the socket head cap of the fractured Prototype 5 screw fragment.

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