ENDO(M3.2)_ BIOMECHNICAL PROPERTIES

Best’s method

was introduced in 1960 by Best

Best’s method

in this, a steel 10mm pin is fixed to the labial

surface of root with utility was, keeping it

parallel to the long axis of the tooth

Bregman’s method

25mm length fat probes are prepared

Bregman’s method

have a steel blade fixed with acrylic

resin as a stop, leaving a free end of 10mm for

placing in root canal

Bramante’s method

was introduced in 1974

Bramante’s method

in this, stainless steel probes are used,

which are bent at a right angle

a. A: internal angle of intersection of

incisal and radicular probe segment

b. B: apical part of the probe

c. C: apex of the tooth

ff reference points are

made IN BRAMANTE’S METHOD:

Grossman method/

wherein an instrument is inserted into the

canal, then a stopper is fixed to the reference

point and radiograph is taken

Weine’s method

If there is no resorption- subtract 1mm

If there is periapical bone resorption-

subtract 1.5mm

If there is periapical bone and root apex

resorption- subtract 2mm ***resorption and

abscess

1mm

is subtracted if there is no resorption (weine’s methof)

1.5mm

is subtracted if there is periapical bone resorption (weine’s methof)

2mm

is subtracted if there is periapical and root apex resorption (weine’s methof)

Kuttler’s method

wherein the DCJ is explained histologically but

not clinically

Kuttler’s method

stated that canal preparation should

terminate at apical constriction

Kuttler’s method

Technique

• locate minor and major diameter on

preoperative radiograph

• estimate length of roots from

peoperative radiograph

• estimate canal width on radiograph

10 or 15 size instrument

__ is used if the canal is narrow

20-25 mm size instrument

__ is used if the canal is within the averge width

30-35 size instrument

__ is used if the canal is wide

readjust the file and

take second radiograph

if the file is too long or short by

>1mm from minor diameter/apical

constriction __

.5mm

for younger pt, if the file reached the major

diameter/apical foramen, subtract __

.67mm

for older pt, if the file reached the major

diameter/apical foramen, subtract __

Kuttler’s method

adv: minimal errors

Kuttler’s method

adv: has shown many successful cases

Kuttler’s method

disadv: time consuming and complicated

Kuttler’s method

disadv: requires excellent quality radiographs

Radiographic grid

was designed by Everett and Fixolt in 1963

Radiographic grid

a simple method in which is a millimeter grid

is superimposed on the radiograph

Radiographic grid

this overcomes the need for calculation

Radiographic grid

not a good method if the radiograph is bent

during exposure

Endometric probe

in this method, one uses the graduations on

diagnostic file which are visible on radiograph

Endometric probe

its main disadvantage is that the smallest file

size to be use dis number 25

Direct digital radiography

digital image is formed which is

represented by spatially distributed set of

discrete sensors and pixels

○

radiovisiography

○

phosphor imaging system

two types of digital radiography:

Xerordiography

a new method for recording images without

film

Xerordiography

image is recorded on an

aluminum plate coated with selenium

particles

Xerordiography

offers “edge

enhancement” and good detail

Xerordiography

has the ability to have both positive

and negative prints together

Xerordiography

improves visualization of files and

canals

Xerordiography

two times more sensitive than

conventional D-speed films

Xerordiography

may cause discomfort

to the patient

Xerordiography

exposure time varies according to

thickness of the plate

15 minutes

in xerordiography, the process of development cannot be delayed for __

Development

process in the

processor unit which converts the

latent image to a positive image

Aluminum plate

removed from

the cassette and subjected to

relaxation which removes old images,

then these are electrostatically

charged and inserted into the

cassette

Digital tactile sense

in this, the clinician may see an increase in

resistance as file reaches the apical 2-3mm

Digital tactile sense

time saving

Digital tactile sense

no radiation exposure

Digital tactile sense

does not always provide the accurate

readings

narrow canals

in the case of __, one

may feel increased resistance as file

approaches apical 2-3mm

immature

apex

in the case of teeth with __, instrument can go periapically

Apical periodontal sensitivity test

this method is based on patient’s response to

pain

necrotic

pulp

in the cases of canal with __, instrument can pass beyond

apical constriction

vital or inflamed pulp

in the case of __,

pain may occur several mm before

periapex is crossed by the instrument

Paper point measurement method

in this method, paper point is gently passed in

the root canal to estimate the working length

Paper point measurement method

most reliable in cases of open apex

Paper point measurement method

used as a supplementary method

moisture of blood

indicates

that paper point has passed beyond

estimated working length

Open apex-

where apical

constriction is lost because of

perforation or resorption

ELECTRONIC APEX LOCATORS

used to locate the apical constriction or cementodentinal

junction, or apical foramen, but not the radiographic apex

ELECTRONIC APEX LOCATORS

has different components: lip clip, file clip, electronic device,

and cord

: lip clip, file clip, electronic device,

and cord

different components of electronic apex locator

ELECTRONIC APEX LOCATORS

provide objective information with high

degree of accuracy (90-98%)

ELECTRONIC APEX LOCATORS

are also available in

combination with pulp tester and can be used

to test pulp vitality

ELECTRONIC APEX LOCATORS

can provide inaccurate readings in cases of

too wet or too dry canal, use of narrow file,

blockage of canal, incomplete circuit, or low

battery

ELECTRONIC APEX LOCATORS

has chances of overestimation

ELECTRONIC APEX LOCATORS

may pose problem in teeth with immature

apex

ELECTRONIC APEX LOCATORS

useful in conditions where apical portion of

canal system is obstructed with impacted

teeth, zygomatic arch, tori, excessive bone

density, overlapping roots, shallow palatal vault

ELECTRONIC APEX LOCATORS

useful in patients who cannot tolerate X ray

film placement because of gag reflex

ELECTRONIC APEX LOCATORS

useful in pregnant patients children, disabled pt, and pt who are heavily sedated

ELECTRONIC APEX LOCATORS

detecting site of root perforations

ELECTRONIC APEX LOCATORS

tool for diagnosis of external and internal

resorption which have penetrated

root surface

ELECTRONIC APEX LOCATORS

detects of horizontal and vertical

root fracture

ELECTRONIC APEX LOCATORS

determines perforations

caused during post operations

ELECTRONIC APEX LOCATORS

tests the vitality of the pulp

resistance apex locator

FIRST GENERATION APEX LOCATOR

resistance apex locator

measures opposition to flow of direct current

resistance apex locator

based on the principle that resistance offered by periodontal

ligament, and oral mucous membrane is the same

resistance apex locator

can detect perforations, be used with k file, and may

incorporate pulp tester

Impedance based apex locator or low frequency AL

was introduced by Inoue

Impedance based apex locator or low frequency AL

measures opposition to flow of alternating

current

Impedance based apex locator or low frequency AL

indicates the apex when two

impedance values approach each other

Impedance based apex locator or low frequency AL

does not require lip clip

Impedance based apex locator or low frequency AL

no patient

sensitivity but difficult to operate

Impedance based apex locator or low frequency AL

requires

coated probes, and cannot be used with files

High frequency apex locators

THIRD GENERATION APEX LOCATOR

High frequency apex locators

also known as frequency dependent

High frequency apex locators

more appropriately termed as “comparative

impedance

coronal part of the

canal

has least impedance

CEJ

has greatest impedance

FOURTH GENERATION APEX LOCATORS

measures resistance and capacitance separately

FOURTH GENERATION APEX LOCATORS

can perform well in relatively dry canals

FOURTH GENERATION APEX LOCATORS

difficult to use in cases of heavy exudates or weeping canals

FIFTH GENERATION APEX LOCATOR

shows accurate reading in presence of dry, wet, saline, EDTA,

blood, or sodium hypochlorite

Tri Auto ZX

a cordless electric endodontic handpiece with

built in root ZX apex locator

Autostart stop mechanism

handpiece starts rotation

when instrument enters

the canal and stops when it

is removed

Autotorque reverse mechanism

handpiece automatically

stops and reverse rotation

when torque threshold

exceeds

Autotorque reverse mechanism

prevents instrument

breakage

Autoapical reverse mechanism

halting and reversing

rotation upon reaching the

destined distance from the

apical constriction

safeguarding against

apical perforation

APICAL GAUGING

a mechanical term which clinically indicates the

measuring of the apical diameter to obstruction of

the root canal system