air abrasion as an adjunct to conventional acid

8/12/2019 Air Abrasion as an Adjunct to Conventional Acid

1/29


2/29


3/29

Micro-etching is an effective method of cleaning

brackets after accidental de-bonding.

conventional bonding

toxicity of acid to oral tissues

the time taken for obtaining the desired

dissolution

Air abrasion

typical tooth surface preparation time

ranging from 0.5 to 3 seconds, without the

additional step of rinsing.


4/29

Purpose of the study

To determine the mean shear debonding force of

metal brackets following enamel preparation with

acid etching alone or sandblasting or a

combination of sandblasting and acid etching.


5/29

METHODOLOGY

80 freshly extracted premolar teeth for the

orthodontic treatment, were collected and stored in

distilled water.

INCLUSION CRITERIA intact buccal and lingual enamel with no cracks

no caries.

The teeth were thoroughly cleaned of any soft tissuedebris or blood and were stored immediately in

distilled water at room temperature.


6/29

The selected teeth were mounted in cold cure acrylic

resin poured in metal rings

The teeth were embedded in the acrylic horizontally

in such a way that the long axis of the tooth was

perpendicular to the central axis of metal ring and

the palatal or lingual cusp and a part of the root

surface was embedded in the acrylic for retention.


7/29


8/29

The mounted teeth were randomly divided into fourgroups, consisting of 20 teeth each.

Group I specimens -green colouracid etched with37% phosphoric acid for 15seconds.

Group II specimens -white colour- sandblasted with 50micron aluminium oxide by a microetcher.

Group III specimens - blue colour- enamel surfacepolished with pumice followed by acid etching with

37% phosphoric acid for 15 seconds. Group IV specimens -red colour- sandblasted with 50

micron aluminium oxide by a micro etcher followed byacid etching with 37% phosphoric acid for 15 seconds


9/29

Materials used

A no-mix chemically cured adhesive (Rely-a-Bond,

Reliance Orthodontic Products, Inc.,Illinois, USA)

MICROETCHER TM ERC (DANVILLEMATERIALS, SAN

RAMON, CA) -The intraoral sandblaster used in this

study was

0.022 inch slot stainless steel premolar PEA Roth

brackets ( Gemini series, 3M Unitek).


10/29


11/29


12/29

TESTING APPARATUS

An Instron Universal Testing Machine Model no.

4467, with 3000 Kg load cell, at a crosshead speed of

0.5mm/second was used to debond the brackets

(Fig.3). For shear testing, the prepared metal ring was fixed

to the aluminum jig, which in turn was secured in the

lower jaw (crosshead), with the long axis of tooth

and bracket base parallel to the direction of shearforce applied.


13/29


14/29


15/29


16/29

RESULTS

On comparing the mean shear bond strength

Group I(acid etched group),

Group II (sandblasted group),

Group III (pumiced and acid etched) and

Group IV (sandblasted and acid etched group)

One-way ANOVA (Analysis of Variance) test

there was a statistically significant differencebetween the four groups (p


17/29

The highest mean shear bond strength on debonding

was found in Group IV (sandblasted and acid etched

group), followed by Group III (pumiced and acid

etched group)and Group I (acid etched group) and

the lowest mean shear bond strength on debonding

was found in Group II (sandblasted group).


18/29

There exists no statistically significant

difference in the mean shear bond strength

between Group I (acid etched group) and

Group III (pumiced and acid etched).


19/29

Group Comparison Mean

p

Difference SD p

Group I Group IIGroup III

Group IV

3.146 .1574-.076 .1574

-1.104 .1574

.000

.998

.000

Group II Group III

Group IV

-3.223 .1574

-4.251 .1574

.000

Group III Group IV -1.028 .1574 .000


20/29


21/29

Discussion

The micro etcher, the most commonly used micro

sandblaster has recently been approved by the FDA for

intra oral use.

The dental chair-side model includes a contra-angle

nozzle and rear-mounted abrasive jars containing the

aluminium oxide powder.

The tubing is connected to a compressed air source in

the operatory.


22/29

Marc E.Olsen, et al compared the traditional acid-etch

technique with the air-abrasion surface preparation

technique, using two different sizes of abrading particles.

The results indicated that there was a significant

difference in the shear bond strengths among the acid

etched group (10.4 2.8 MPa), the 50 micron group (2.3

1.0 MPa) and the 90 micron group (3.6 2.2 MPa)

(p=0.0001).


23/29


24/29

Karen R. et al.[7] compared four methods of enamel

preparations before orthodontic bonding.

Sandblasting without acid etching produced lower

bond strengths than sandblasting followed by acidetching.

The greatest debonding force was achieved by

sandblasting before acid etching, even though this

was not statistically significant when compared with

the other groups, which were also acid etched.


25/29


26/29

The effect of enamel air abrasion on the retention of

bonded metallic orthodontic brackets

AJO-DO 2003

The purpose of this study was to compare the conventional acid-etch technique with an air abrasion surface preparation technique.

Eighty freshly extracted noncarious human premolar teeth wererandomly divided into the following 4 groups: (1) acid etched with37% phosphoric acid for 15 seconds (Express Dental Products,

Toronto, Canada), (2) sandblasted with 50 aluminum oxide by a microetcher

(Danville Engineering Inc, Danville, Calif),

(3) polished with pumice followed by acid etched with 37%phosphoric acid for 15 seconds,

(4) sandblasted with 50 aluminum oxide by a microetcherfollowed by acid etched with 37% phosphoric acid for 15 seconds.

All the groups had stainless steel brackets (Dentaurum, StandardEdgewise) bonded to the buccal surface of each tooth with no-mixadhesive (Express Dental Products, Toronto, Canada).


27/29

The air abrasion technique versus the conventional acid etching


28/29

The air-abrasion technique versus the conventional acid-etching

technique: A quantification of surface enamel loss and

a comparison of shear bond strength

(Am J Orthod Dentofacial Orthop 2000;117:2

To quantify the surface enamel loss that results when an air-

abrasive technique is used and to compare the shear bond

strength of different prebonding and bonding methods.

2 enamel-conditioning methods: acid etching with 37%

phosphoric acid; and sandblasting with 50 maluminum

oxide particles under different conditions.

A profilometer was used

The results - the enamel loss associated with sandblasting is

equal to or smaller than that resulting from acid etching.


29/29

air abrasion as an adjunct to conventional acid

Documents