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INTRODUCTIONWhat is a dental attachment

METHOD OF STUDY

RESULT

ABSTRACT

International standard, ISO for dental

attachment

Before Amendment After Amendment

ISO 13017:2015 ISO 13017:2020

Performance Test Methods of Dental Materials(Magnetic Attachment, Dental Ceramic) Reflecting Latest International Standards

Ji-Min Yu, Seen-Young Kang, Jun-Seok Lee, Jae-Won Lee, Ho-Sang Jung, Seung-Youl Lee*Medical Device Research Division, NIFDS, Ministry of Food And Drug Safety, Osong, Korea

E-mail : dasom1022@korea.kr

comparison of international standard (ISO 13356) revisionsrelated to dental attachments

Definition

Device used to secure the crown of a restoration or to accurately stabilize removable dentures. There

are fixators in the crown and fixators outside the crown.There are various types of dental attachments,

such as stud type, bar type, and magnetic type. Among these, magnetic attachments are actively used

for advantages such as reducing lateral pressure applied to an implant by using the force of magnetic

force, convenient attachment and detachment of dentures, and excellent vertical holding power.

International standard, ISO for zirconia

ceramic

Before Amendment After Amendment

ISO 6872:2008 ISO 6872:2015

Examples Application

What is a dental ceramic

Definition

It is a ceramic material used to manufacture dental restorations such as inlays, artificial teeth, crowns,

bridges, etc. It is a ceramic material that is processed by a dental computer-assisted design and

manufacturing unit. Dental ceramic, which is a material for tooth-shaped prostheses used in removable

dentures, is very promising due to its mechanical strength comparable to metals and excellent esthetics.

Examples Application

The bonding surfaces of the magnet (or magnetic

assembly) and the keeper or other magnet are

bonded to the top and bottom of the ball bearing

slider using cyanoacrylate adhesive. A low-friction

ball bearing slider that can hold the specimen and

pull it vertically is mounted on a mechanical

property tester. The load is applied at a crosshead

speed of 2.0 mm/min or less until the magnet (or

magnetic assembly) is completely separated from

the keeper or other magnet. Tensile force

measurement is carried out until the measured force

value remains constant within the range of ± 0.01 N,

then the machine is stopped. The holding power test

for the same set is repeated 5 times.

Retentive force method of ISO 13017:2020

3-point flexural strength method of ISO 6872:2015 Specimen dimensions used for flexural strength: Width (4 ± 0,2) mm

(dimension of the side at right angles to the direction of the applied

load), Thickness: (2,1 ± 1,1) mm (with 3,0 mm recommended;

dimension of the side parallel to the direction of the applied load),

Chamfer c = (0,12 ± 0,03) mm [with a maximum of 0,10 mm

recommended for small thickness specimens (b < 2,0 mm)] Universal

mechanical testing machine: capable of a crosshead speed of (1 ± 0,5)

mm/min and an ability to measure applied loads of between 10 N and

[1 000 N or 2 500 N] Fixture for three-point bending: consisting of

support rollers(1,5mm to 5mm ± 0,2mm, in diameter) positioned with

their centres 12,0 mm to 40,0 mm (± 0,5 mm) apart. The load shall be

applied at the midpoint between the supports by means of a third roller

(1,5 mm to 5 mm ± 0,2 mm, in diameter). Method: Measure the cross-

sectional dimensions of each test piece to ±0,01mm. Then, place a test

piece centrally. on the bearers of the test

Flexural strength result of zirconia material dental ceramic

Flexure stress at Maximum Flexure

load (MPa)

3hr 57min 6hr 28min 10hr 51min

1 810.16 791.80 826.03

2 731.34 984.72 823.49

3 734.18 605.70 915.01

4 651.90 725.89 668.46

5 796.32 783.77 726.11

6 932.04 644.53 787.34

7 802.82 1010.28 782.72

8 812.05 867.65 843.02

9 860.53 865.68 667.42

10 823.43 853.99 734.83

11 695.40 837.48 677.47

12 805.54 938.61 682.63

13 734.12 634.54 761.27

14 740.34 666.30 906.53

15 638.25 733.46 639.42

Maximum 932.04 1010.28 915.01

Median 796.32 791.80 761.27

Minimum 638.25 605.70 639.42

Standard

Deviation78.15 127.61 87.83

Mean 771.23 796.29 762.78

Recommended clinical indicationsFlexural strength minimum value

[MPa]

1a) Monolithic ceramic for single-unit anterior prostheses, veneers, inlays, or onlaysadhesively cemented.

b) Ceramic for coverage of a metal framework or a ceramic substructure.

50

50

2

a) Monolithic ceramic for single-unit anterior or posterior prostheses adhesively cemented.

b) Partially or fully covered substructure ceramic for single-unit anterior or posterior prostheses adhesively

cemented.

100

100

3

a) Monolithic ceramic for single-unit anterior or posterior prostheses and for three-unit prostheses not involving

molar restoration adhesively or non-adhesively cemented.

b) Partially or fully covered substructure for sin-gle-unit anterior or posterior prostheses and for three-unit prostheses

not involving molar restoration adhesively or non-adhesively cemented.

300

300

4a) Monolithic ceramic for three-unit prostheses involving molar restoration.

b) Partially or fully covered substructure for three-unit prostheses involving molar restoration.

500

500

5Monolithic ceramic for prostheses involving partially or fully covered substructure for four or more units or fully

covered substructure for prostheses involving four or more units.800

The experimental results were 771 MPa in (1group: 3hr 57min), 796 MPa in

(2group: 6hr 28min), and 753 MPa in (3group: 10hr 51min). All three groups

showed similar strength, but it was the best at 6hr 28min, and the mechanical

strength of zirconia ceramic was found to be affected by the firing time.

Figure I. Schematic diagrams of closed magnetic circuit

attachment: left) sandwich type, right) cup-yoke type Figure2.Typeofattachment

Balltype Magnetictype BartypeTelescopictype

Figure 3.. Zirconia ceramic blocks Figure4.Examplesofrestorationsfordentalprostheses

Figure 5. Device using a low friction ball bearing slider for fixing and pulling the specimens vertically

Figure 6. Flexural strength test machine

Figure 7. Production process of specimen using CAD(computer aided design)/CAM( computer aided manufacturing)

machine so that the load is applied to a 4mm wide face along a line perpendicular to the long axis of the test piece

and determine to ±0,1 N the load required to break the test piece. Use a cross head speed of (1 ± 0,5) mm/min.

Repeat the procedure with the remaining test pieces.

contents ISO13017:2012(Amd2015) ISO 13017:2020 revision

6.3 Retentive force

6.3.2 Test procedure

Load the test specimen in tension in the mechanical

testing machine at a cross-head speed of 5.0 mm

min−1 or less until the magnet or the magnetic

assembly separates completely from the keeper.

Load the test specimen in tension in the mechanical

testing machine at a cross-head speed of 2.0 mm/min or

less until the magnet or magnetic assembly separates

completely fromthekeeperortheothermagnet.

Cross-head

speed 5 → 2

6.3.3 Fixing procedure

6.3.3.1 Fixation of

specimens

Adjust the position of the lower-table equipped with the

device using the X-Y stage so that both centers of the

lower and upper-table are aligned. Attach the mating

face of the magnet (or magnetic assembly) to the centre

of the lower-table using an adhesive double sided tape.

Note that the side attached to the double sided tape will

be theside thatmateswiththeothermagnet (orkeeper)

oncethealignmentprocedure iscompleted.

Adjust the position of the lower non-magnetic table

equipped with the device using the X-Y stage so that

both centers of the lower and upper non-magnetic table

are aligned. Provisionally place the mating face of the

magnet (ormagneticassembly) to thecentreof the lower

non-magnetic table.Note that theside incontactwiththe

lowernon-magnetic tablewillbe theside thatmateswith

the other magnet (or keeper) once this alignment

procedure iscompleted.

Adhesive double

sided tape delete

Retention force

graph change

6.3.5 Analysis -

Convert the time values on X axis into distance

according to the Formula (1). Speed is a constant value

since the same crosshead speed is maintained

throughout theexperiment.

d=v× t (1)

where

disthedistance, inmm;

visthespeed, inmm/min

t is thetime, inmin.

Retention force

analysis

description

added

CONCLUSION

REFERENCE

ACKNOWLEDGMENTThe research was supported by a grant (18171MFDS301, 20171MFDS346) from Ministry of Food and

Drug Safety in 2018, 2020.

The results of this study contribute to the vitalization of the Korean dental medical device industry and

keep pace with the latest research trends by conducting research on the mechanical properties of

removable dentures and dental prostheses by applying the newly revised international standard test

method.

[1] 13017:2020Dentistry—Magnetic attachments.

[2] ISO6872:2015Dentistry—Ceramic materials .

[3] M.A. Tara, S. Eschbach, S. Wolfart, M. Kern, Zirconia ceramic inlay-retained fixed dental prostheses – first clinical results with a new

design.

공익신고자 보호제도란?

-공익신고자등(친족 또는 동거인 포함)이 공익신고 등으로 인하여 피해를 받지 않도록 비밀보장, 불이익보호조치, 신변보호조치 등을 통하여 보호

하는 제도

♣보호조치 요구 방법

전화02-360-3761/우편(120-705)서울시서대문구통일로81국민권익위원회공익보호지원과/팩스02-360-3567

The purpose of this study is to evaluate the mechanical properties of a dental prosthesis used with restoring a removable denture when there is partial loss of teeth, and also to guide the revision status and

up-to-date of the international standards applied in the mechanical property evaluation. When a lost tooth is restored with a removable denture, a medical device called a dental attachment is used to help

the removable denture be positioned in a stable state without being separated from the gum. This study is to evaluate Magnetic attachment with excellent retention and easy attachment and detachment of

dentures, and Zirconia ceramic used as artificial teeth for removable denture. The standard related to dental attachments are ISO 13017 Dentistry — Magnetic attachments, and the standards for dental

ceramics made of zirconia are ISO 6872 Dentistry — Ceramic materials and ISO 13356 Implants for surgery — Ceramic materials based on yttria-stabilized tetragonal zirconia (Y-TZP). The ISO 13017

standard was revised in 2020, and ISO 6872 and ISO13356 were revised in 2015, respectively.

Table 1. Comparative analysis of the revisions of international standard 13017

Table 1. Classification of ceramics for fixed prostheses by intended clinical use with required

mechanical properties

Table 3. 3-point bending strength test result

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