NiTi Briefly

7/29/2019 NiTi Briefly

1/15

Introduction to NiTi The navy worked with NiTi alloy in the

1950s and 1960s

They were looking for a non-magnetic,

waterproof, and salt resistant material

Initial tests found NiTi to be superelastic


2/15

NiTi particularly exhibits superelastic

behavior between 10oC125oC

Other alloys with superelastic properties are

the alloys of copper-zinc, copper-aluminum,

or titanium-niobium

Ideal temperature range in endodontics is

23oC to 36oC, the temperatures found in the

composition of 50% Ni and 50% Ti


3/15

Orthodontics began using NiTi in the late

1970s

NiTi was also useful in wiring fractures in

orthopedics and oral surgery

Initial work proved NiTi resisted corrosionin the body and was extremely

biocompatible


4/15

The First Use of NiTi in

Endodontic Hand Files Walia, Brantley, and Gerstein conducted the

first reported investigation of the NiTi alloy

in endodontics in 1988

Testing concluded that the NiTi had two to

three times the elastic flexibility and greaterresistance to torsion fractures


5/15

By 1991 Quality Dental (Johnson City,

TN), developed a process for grinding NiTialloy files for NiTi Co. (Chattanooga, TN)

It was reported to be 500% more flexible

than conventional stainless steel and said to

be capable of withstanding 1000% morestress than conventional stainless steel


6/15

University of South Carolina conducted astudy in 1992 with their pre-doctoral

students

Fewer cases of broken instruments,

perforations, and ledges occurred in thegroup using NiTi hand files


7/15

University of Tennessee conducted a similarstudy in 1993 with their pre-doctoralstudents

Students using NiTi hand files had

significantly higher grades, instrumentedthe canals significantly faster, and hadoverall superior results

NiTi files seemed to work more efficientlyin a reaming motion rather than a filingmotion


8/15

Table 1: This table illustrates the procedural errors

made by the students during their proficiency exam

with the two sets of files. (* Statistically significant)


9/15

The First Use of NiTi in

Endodontic Rotary Files 1991 NiTi Co. had two rotary file designs to

make up their file line

These two file designs were developed

uniquely for continuous 360o rotation


10/15

The first file design, U-File design, which

continues to be offered today as the Profile,

GT and LightSpeed, for sizes #15 through

#35

The second file design, the Sensor File, was

used in sizes #40-#60 and incorporated twosets of flutes having different helical angles


11/15

Oregon Health Sciences Universitycompared four instrumentation techniques

1) Step-back preparation with K-files

2) Crown-down preparation with K-files

3) Sonic instrumentation with Shaper-

Sonic files

4) NiTiMatic preparation system with NiTi

rotary files


12/15

Incidence of zipping, ledging, and elbow

formation was found to be the lowest with

the use of the NiTiMatic preparation system

with NiTi rotary files


13/15

In 1993 the University of Tennesseeconducted a study comparing hand stainlesssteel, hand NiTi files, and the NiTiMaticpreparation system with NiTi rotary files

They found the rotary files to have achieved

the same shaping goals in about half thetime of the other two groups:

Rotary 173 s Hand stainless 328 s

Hand NiTi 351 s


14/15

The NiTi rotary was found to have maintainedthe apical shape better, indicating fewer ziptype procedural errors

Amount of material removed at the workinglength:

Rotary 0.017 mm

Hand NiTi 0.023 mm

Hand stainless steel 0.139 mm

They also found the canal width of the innerwall to be closer to the original width and

more centered with the rotary group


15/15

This illustrates the increase in canal width on the

inside of the curve at the point of curvature.

NiTi Briefly

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