PRESENTED BY:

FASAHAT AHMED BUTT

ROLL# 36

GROUP: C

DEBONDING PROCEDURES

IN ORTHODONTICS

OBJECTIVE

To remove the attachment and all the

adhesive resin from the tooth and restore

the surface as closely as possible to its

pretreatment condition without inducing

iatrogenic damage

PROCEDURES

Bracket removal

Steel bracket

Ceramic bracket

Removal of residual adhesive

Steel bracketsCeramic

brackets

REMOVAL OF STEEL

BRACKETS

Place the tip of bracket remover against mesial and

distal (or occluso-cervically) edges of the bonding base

and cut the brackets off

A gentler technique is to squeeze the bracket wings

mesiodistally and lift the bracket with the peel force

REMOVAL OF CERAMIC

BRACKETS With the introduction of ceramic brackets, a new

concern over enamel fracture and loss from

debonding has arisen.

Because of differences in bracket chemistry and

bonding mechanism, various ceramic brackets

behave differently on debonding

More recent ceramic brackets have

mechanical lock base and vertical slot

that will split the bracket by squeezing

CERAMIC BASE DESIGN

MEANS OF REMOVAL

Mechanical

Thermal debonding

Lasers

Ultrasonic

MECHANICAL

ELECTROTHERMAL

Takla and Shivapuja (1995) study in which 30 teeth were schduled for orthodontic extractions

15 extracted 24 days after ETD

7 extracted 28-32 days after ETD

8 were control teeth and debonded by conventional method, with pliers

In control group pulp was normal

Significant hyperemia in teeth extracted after 24 day

In case of teeth extracted after 28-32 day variation was seen from complete recovery to persistent inflammation

Jost-Brinkmann et al (1997) did an in vivo study in which 12 human premolars scheduled for extraction were bonded with ceramic brackets which were subsequently debonded using ETD. After 4 weeks, teeth were extracted and histologically examined . No signs of pulpal inflammation were seen

LASERS

The use of laser eliminates problems like enamel tear

outs, bracket failures and pain.

Lasers decreases debonding force and less time

consuming.

Strobl et al (1993) Removal of ceramic brackets from

enamel surface by means of laser heating was investigated

with the use of C02 and YAG laser

Polycrystalline alumina

Monocrystalline alumina

Laser-aided debonding significantly reduced debonding

force by thermal softening of adhesive resin.

In 69-75% incident light reached enamel surface when

Nd:YAG laser was used which has the potential to cause

pain or damage to tooth surface

ULTRASONIC

DEBONDIN

G

METHODS

ADVANTAGES DISADVANTAGES

Mechanical Low cost Risk of enamel fracture

Electrothermal o Reduced incidence of

bracket failure

o Short debonding time

Potential for pulpal damage

and mucosal burn

Laser Experimental, but

increased precision

regarding time and

amount of heat

application

High cost of equipment

Ultrasonic o Potentially reduced

enamel damage

o Reduced likelihood of

bracket failure

o Adhesive removal after

debonding may be

achieved with same

o Increased debonding time.

o Extensive wear of

expensive ultrasonic tip

o Some force required

o Potential for soft tissue

injury

ADHESIVE REMNANT INDEX

(ARI)

Used to evaluate the amount of adhesive left on the tooth

after debonding

SCORE 0: No adhesive left on tooth

SCORE 1: Less than half of adhesive left

SCORE 2: More than half left

SCORE 3: All adhesive left on tooth with distinct with

distinct impression of bracket mesh

RESIDUAL ADHESIVE

SCOR

E 0

SCOR

E 1

SCOR

E 2

SCOR

E 3

REMOVAL OF RESIDUAL RESIN

Ultrasonic scaler

Scraping with a sharp bond removing removing plier

Burs

Tungsten carbide bur

Ultrafine diamond bur

White stone finishing bur

ENAMEL SURFACE INDEX

SCORE 0: Instrument tested left the tooth surface with its

perikymata intact

SCORE 1: Plain cut and spiral fluted tungsten carbide burs

operated at about 25,000 rpm were the only instruments that

provided the satisfactory surface appearance

SCORE 2: Fine sandpaper disks produced several

considerable and some even deeper scratches

SCORE 3: Medium sandpaper disks and a green rubber

wheel produced similar scratches, that could not be

polished away

SCORE 4: Diamond instruments were unacceptable

and even fine diamond burs produced coarse

scratches and gave a deeply marred appearance

POLISHING