bonding-i / orthodontic courses by indian dental academy
TRANSCRIPT
1
BONDING IN ORTHODONTICS – II
INDIAN DENTAL ACADEMY
Leader in continuing dental education www.indiandentalacademy.com
www.indiandentalacademy.com
2
CONTENTS1. Evolution of bonding
agents2. Banding3. Indirect bonding4. Bonding to special
surfaces5. Bond strength6. Debonding 7. Decalcification and
demineralization8. Hazards of bonding
www.indiandentalacademy.com
3
EVOLUTION OF BONDING MATERIALS
“An appliance which cannot be
made transparent or tooth-colored
should at least be made smaller.”
www.indiandentalacademy.com
4
Schange’s adjustable clamp band Angle’s retraction screw
1871 - W.E. MAGILL – Zinc oxycloridewww.indiandentalacademy.com
5
Laborious, time-consuming, skill Partially erupted teeth Decalcification /discoloration Gingival irritation Unaesthetic Need of separators Closure of band spaces – “What you see
is not what you get”
www.indiandentalacademy.com
6www.indiandentalacademy.com
7
3 major developments that made bonding of attachments to teeth possible –
1. BUONOCORE 1955 – improved retention of methyl methacrylate to enamel – 85% phosphoric acid for 30 seconds
2. BOWEN 1962 – bis Glycidyl methacrylate – more stable and greater strength
3. NEWMAN 1965 – first to acid etch and bond orthodontic brackets with epoxy resin
www.indiandentalacademy.com
8
Orthodontic attachments had to be cemented on teeth instead of the intermediary bands-
Methylmethacrylate monomer –MMA – first material to be used
Catalyst – Benzoyl peroxide –BPO Powder-liquid system In use in restorative dentistry
•Poor adhesion - Polymerization shrinkage•Pulpal irritation
www.indiandentalacademy.com
9
BUONOCORE (1955) –
Improved retention of methyl methacrylate to enamel – 85% phosphoric acid for 30 seconds
Not successful for orthodontic purposes –
• Occlusal force • Wide range of oral thermal change • Wet environment
www.indiandentalacademy.com
10
G. V. NEWMAN (1965)
Bonded plastic brackets with epoxy resins
Start of direct bonding procedure
For short-term treatment with anterior brackets
Did not replace ‘metal-band’ system
www.indiandentalacademy.com
11
First commercially available orthodontic adhesives
1. OIS Adhesive system – OIS company in 19692. Bracket Bond – GAC in 1970
MMA -BPO-amine catalyst system Weak Adhesion Early 70s - all adhesives consisted of MMA - it bonded
chemically to plastic brackets – in vogue
www.indiandentalacademy.com
12
Fujio Miura and associates in 1971 –
Introduced – ORTHOMITE MMA - Tri–N–Butyl Borane (catalyst) Increased adhesive strength Coupling agent – ‘silane’
methacryloxypropyltrimethoxysilane Increased adhesive penetration
•Chemically bonded to adhesive•Affinity to enamel
www.indiandentalacademy.com
13
Merits of MMA adhesives:
1. Plastic brackets 2. Good storage stability3. Increased working time – brush-on / dip-in4. Elimination of sealant - good penetration
into enamel surface5. Less damage during debonding
www.indiandentalacademy.com
14
Demerits of MMA adhesives:
1. Fluctuating proportion of powder-liquid depending on operator
2. Poor mechanical interlocking to metal bracket bases
www.indiandentalacademy.com
15
Metal brackets enter the scene
Plastic – worry about enamel-adhesive Enamel-adhesive & adhesive-bracket
Adhesive-bracket -Mesh, perforated pad , foil mesh Enamel-adhesive –
•Increased hardness of adhesive•MMA BisGMA •Filler material - TEGDMA
www.indiandentalacademy.com
16
Bisphenol Glycidyl Dimethacrylate (Bis-GMA)
BOWEN 1962• Greater strength• Lower water absorption• Less polymerization shrinkage
2-paste system Strongest adhesives for metal brackets
www.indiandentalacademy.com
17
FILLERS: Reduce viscosity of resin Reduce polymerization shrinkage Quartz, silica glass particles 3 - 20 microns - abrasion resistance 0.2 – 0.3 microns - smooth surface - less plaque
retentionAdhesives with large particle fillers
recommended for extra bond strength, but careful removal of excess is mandatory
www.indiandentalacademy.com
18
Di/triethyl glycol dimethacrylate (TEGDMA)
www.indiandentalacademy.com
19
Merit and demerit of Bis-GMA – hardness
Poor penetration due to increased viscosity – dilute with MMA
Plastic brackets could not be used – primer for partially dissolving added
Active life less than powder liquid system
www.indiandentalacademy.com
20
In 1974 – ORTHOMITE II – 20% more HNPM – hydroxynapthoxypropylmethacrylate Eliminated silane
4 - META – methacryloxyethyl trimellitate anhydride
ORTHOMITE SUPER BOND
www.indiandentalacademy.com
21
4 - META
Plastic & metal PRE-PRIMED brackets Base was primed with adhesive Bracket base covered with PMMA powder Base dipped in monomer and pressed onto
etched surface. Bond strength less than manual application
www.indiandentalacademy.com
22
Orthodontic adhesives are variations of- Adhesives Direct-restorative materials used in
restorative dentistry
Late 20th century –direct restorative biomaterials
1. Resin-matrix – originated in U.S.2. Salt-matrix – U.K.
www.indiandentalacademy.com
23
1. RESIN MATRIX: Classification -
According to organic matrix components -A. Acrylic resins – MMA Ex. ORTHOMITE, GENIEB. Diacrylate resins- BisGMA Ex.CONCISE, PHASE II
According to polymerisation mechanism –A. Chemically activatedB. Light-curedC. Dual-curedD. Thermocured
www.indiandentalacademy.com
24
A. CHEMICALLY ACTIVATED:
Chemically-cured/ Auto-cured / Self-cured Used since beginning of bonding Most-widely used ortho adhesives Two-paste / one-paste Two-paste system: Initiator- Benzyl peroxide in monomer Activator- tertiary amine – dihydroxyethyl –p-
toluidine
www.indiandentalacademy.com
25
Ex. Concise (3M)
Good bond strength
Laborious Time-consuming Increased air-exposure- oxygen
inhibition Defects – air entrapment, voids
www.indiandentalacademy.com
26
One-paste system:
One adhesive component applied to bracket base and other on tooth surface – catalyst gradient
No-mixing Bracket positioned accurately - pressed firmly into
place Curing occurs – 30-60 secs Ex. Rely-a-bond, System 1+, Unite
www.indiandentalacademy.com
27
Procedure simplified Fast Efficient
Little long term information available on bond strength Inhomogeneous polymerisation – sandwich technique Enamel and bracket side more polymerized Liquid activators – toxic, allergic reactions
www.indiandentalacademy.com
28
B. LIGHT-CURED:
Visible-light curedCamphoroquinoneCure from incisal and gingival areas Increased working time Ideal for educational purpose DC same as Chemical-cure; same for metal and ceramic
brackets Photocuring time-consuming
www.indiandentalacademy.com
29
C. DUAL-CURED:
Intiation – exposure to lightPropagation – chemically cured Advantages of light and chemically cured Improved surface and bulk material properties Highest DC, bond strength Ideal for bonding molar tubes
Most time-consuming Bulk defect due to mixing
www.indiandentalacademy.com
30
D. THERMO-CURED:
Exposure to heat
Superior properties
Not for direct but only indirect bonding
www.indiandentalacademy.com
31
Adhesives acting in the presence of water –
1. MOISTURE-RESISTANT – - can bond in presence of water - saliva, gingival fluid – contaminants - ex. Transbond MIP2. MOISTURE-ACTIVE – - need water for bonding - enamel surface intentionally made wet - Cyanoacrylate – no liquid, only paste - ex. Smartbond
www.indiandentalacademy.com
32
CYANOACRYLATES:
Ethyl-cyanoacrylate – Smartbond-orthodontic bracket adhesive (1991)
Other uses•Automobiles,Circuit boards,Light aircraft•Fracture fixation•Skin sutures•Cardiac surgery•Guided tissue regeneration
www.indiandentalacademy.com
33
Crabb and Wilson – 1971- compared with polycarboxylate cement – poor performance and bond strength, unsuitable for clinical use
Howells and Jones – 1994 – poor performance on storage in saline for a week
Krishnan et al – 1994 –equal to Bis-GMA when kept in 37oC for 24 hours
www.indiandentalacademy.com
34
THOMAS W. - JCO 2000 - Compared the shear bond strength and debonding effects of Smart-Bond & Rely-a-bond
•Smart-Bond’s strength was significantly higher
•No danger of fracturing the enamel•Polycarbonate bracket - work only if
they are pretreated with water
www.indiandentalacademy.com
35
Ideal characteristics of Bonding medium:
1. Non-toxic 2. Adequate working and setting time3. Moderate viscosity4. Ability to wet etched surface5. Sufficient tensile and compressive strength - retain bracket &
ease of debonding6. Resist decomposition in the oral environment7. Antimicrobial
www.indiandentalacademy.com
36
Evaluation of antimicrobial properties of orthodontic composite resin combined with benzalkonium chloride
Othman et al,AJO Sep2002
The antimicrobial agent benzalkonium chloride added to a chemically cured composite resin
Anti microbial benefits and bond strength of the modified composite were evaluated.
www.indiandentalacademy.com
37
Results:
No significant difference between the tensile bond strength between modified composite and the original product
The incorporated BAC added to anti microbial properties of original composite without altering it’s mechanical properties
www.indiandentalacademy.com
38
2. SALT MATRIX: CEMENTS IN ORTHODONTICS:
Desirable properties:1. Adequate working and setting time2. High tensile, compressive and shear stress3. Resistant to dissolution4. Clinically acceptable bond strength5. Low Adhesive Remnant Index (ARI) on debonding6. Anticariogenic potential
www.indiandentalacademy.com
39www.indiandentalacademy.com
40www.indiandentalacademy.com
41
ZINC PHOSPHATE:
Oldest of the luting cements Powder and liquid system Film thickness of 20 microns Efficient mixing characteristics
Mechanical adhesion Pulpal irritant - highly acidic May cause decalcification of enamel resulting in white
spots
www.indiandentalacademy.com
42
ZINC SILICOPHOSPHATE:
Addition of silicate glass Superior strength and fluoride releasing
property
Extremely acidic High solubility No longer used
www.indiandentalacademy.com
43
ZINC POLYCARBOXYLATE CEMENT:
Introduced by Smith in 1968 First cement system that developed a
chemical bond to the tooth structure. Early 70s –Durelon – poor bond strength Combined desirable properties of Zn-
phosphate & ZOE
www.indiandentalacademy.com
44
Acid-base reaction
Chemical bond to tooth Fluoride release Shorter setting time Viscous liquid – less efficient mixing characteristics -
PSEUDOELASTIC
www.indiandentalacademy.com
45
GLASS IONOMER CEMENTS:
Developed and introduced in 1974 byWilson, Kent and Smith.
To combine strength and fluoride release of silicophosphate and adhesive efficiency of carboxylate
Group of materials that use silicate glass powder and an aqueous solution of Polyalkeonic acids
www.indiandentalacademy.com
46
Setting reaction:
Surface of glass particles is attacked by acid Ca, Al, Na, Fl ions-leached into aqueous medium Next 24 hours a new phase forms in which aluminium ions
become bound within the cement matrix leading to a more rigid set cement
NaF uniformly dispersed in the set cement. Unreacted portion of glass particles sheathed by silica gel.
www.indiandentalacademy.com
47
Unreacted powder particles surrounded by a silica gel in an amorphous matrix of hydrated Ca++ and Al+++ polysalts.
During initial reaction if mix contaminated by additional water or ambient air - dissolution of matrix - weak and more soluble cement
Adhesion- chelation of carboxyl groups of polyacids with Ca in apatite of enamel & dentin
www.indiandentalacademy.com
48
Biological properties :
Chemical adhesion Bacteriostatic or bactericidal due to fluoride
release. Acid - less irritating to the surrounding tissues Enamel etching for luting bands not required Reduces demineralization Highest strength Least solubility Bonds to enamel and base metals
www.indiandentalacademy.com
49www.indiandentalacademy.com
50
Drawbacks:
Moisture sensitivity Low early strength
Polymerizable resin functional groups added Impart additional curing process Allow the bulk of the material to mature through the acid-
base reaction.
RESIN MODIFIED GLASS IONOMER CEMENT
www.indiandentalacademy.com
51
Nicholson (Quint Int 1977) “Resin modified GIC’s are those
materials that are modified by the inclusion of resin, generally to make them partly photocurable”
W.M. Tay (Dental update 95) “These are hybrid materials that retain
significant acid base reaction as a part of their overall curing process”
www.indiandentalacademy.com
52
Advantages of RMGIC’s over GIC’s:
1. Sufficiently long working time controlled in command to a snap set by photocuring.
2. Improved setting characteristics.3. Protect the acid base balance from problem of
water balance.4. Rapid development of early strength.5. Fluoride release greater.6. Diametral strength high (20 Mpa compared to 6. 6 Mpa)
www.indiandentalacademy.com
53
Disadvantages of RMGIC’s over GIC’s:
1. Biocompatibility is controversial.2. Setting shrinkage is higher leading to increased
microleakage and poor marginal adaptation Brands
• Fuji Ortho LC• Photacfil – ESPE • Vitrebond – 3M
www.indiandentalacademy.com
54
In 1986 – White described a method of bonding orthodontic brackets to the enamel surfaces of teeth, with a glass ionomer cement.
Poor strength Isolation of newly bonded teeth Light arch-wires immediately after bonding
www.indiandentalacademy.com
55
Bond strength and durability of glass ionomer cements used as bonding agents - AJO July 1989
-Klockowski, Davis, Joynt, Wieczkowski, and MacDo Compared GICs (Ketac-fil, Ketac-cem and Chelon)
with Rely-A-Bond (no-mix autopolymerising) which served as a standard in a clinical study.
www.indiandentalacademy.com
56
Results:
Bond strength of GICs was significantly less when compared to Rely-A-bond.
Less reduction of bond strength of GICs on recycling – lesser than Rely-A-bond on recycling
Failures involved cohesion within cement or adhesion involving the enamel - easily scraped off from the enamel surface without causing much damage.
www.indiandentalacademy.com
57
Cook -1990 compared the in vivo bond strength of a glass ionomer cement, Ketac (ESPE Premier Denbol Products, Norristown, Pa.), with a composite resin bonding agent – 12% failure rate
Fajen et al- 1990 evaluated the bond strength of three glass ionomer cements against a composite resin in vitro
www.indiandentalacademy.com
58
Fricker - 1994, worked with Fuji II LC glass ionomer cement (GC Corp., Kyoto, Japan) –
•Same rate of success bonding brackets to enamel surfaces as he did with composite cements.
•Dentine conditioner was utilized for ten seconds
www.indiandentalacademy.com
59
Kusy - discussed the damage to teeth on debonding after using composite bonding resins.
•“When is stronger better?” •Use of glass ionomer cements for orthodontic
bonding procedures - do not need etching or damage the enamel during debonding.
www.indiandentalacademy.com
60
A new light-cured glass ionomer cement that bonds brackets to teeth without etching in the presence of saliva -AJO-DO SEP 1995
-Silverman, Cohen
Used a new Resin modified GIC Fuji Ortho LC Light-cured, resin-reinforced glass ionomer cement 3 mechanisms of setting
www.indiandentalacademy.com
61
Advantages:
Saves significant amount of chair time. Eliminates working in a dry field. Eliminates etching and priming enamel surfaces. Fluoride release protects teeth against
decalcification. Repairs are quick and easy. Increased patient and operator comfort.
www.indiandentalacademy.com
62
Evaluation of fluoride release from an orthodontic bonding system – AJO-DO Aug 1991
-Samir E. Bishara, Edward J. Swift, Jr., Daniel C. N. Chan,
Light-activated fluoride-releasing - FluorEver OBA Tensile bond strength was significantly less – 1/3 – 1/2 of
conventional (chan et al)
www.indiandentalacademy.com
63
Fluoride ion release – 2.6ppm on day 1
0.42ppm on day 2
0.04ppm on day 43
However , decrease in enamel decalcification was observed.
www.indiandentalacademy.com
64
BANDING
“Feel the pinch”
www.indiandentalacademy.com
65
Advantages of banding
Stronger Protect against interproximal caries Easier to recement and deband
1. CUSTOM-MADE• Indirect• Direct
2. PRE-FORMED
www.indiandentalacademy.com
66
1. CUSTOM-MADE BANDS:
1. Band-pinching2. Band-cementation
1. BAND-PINCHING: ‘Food-trap for cariogenic debris’ Exacting proximity between tooth and
band Poorly fitting band – ‘island in a sea of
cement’.
BANDING PROCEDURE
www.indiandentalacademy.com
67
BAND MATERIAL:
Precious metalChrome-cobalt alloyStainless steel Size:
Thickness WidthIncisors 0.003 – 0.004” 0.125”
Premolars & Canines
0.004” 0.150”
Molars 0.005 – 0.006” 0.180 – 0.200”
www.indiandentalacademy.com
68
REQUIREMENTS:1. Greatest strength and
durability with minimum of bulk
2. Soft enough to permit close adaptation
3. Strong enough to withstand stresses
4. Polishable5. Corrosion and tarnish
resistant6. Biocompatible
www.indiandentalacademy.com
69www.indiandentalacademy.com
70www.indiandentalacademy.com
71www.indiandentalacademy.com
72www.indiandentalacademy.com
73
2. BAND-CEMENTATION:
Do not depend on cement for retention‘Drive fit’
www.indiandentalacademy.com
74
Universal scaler parallel to band margin and not perpendicular
www.indiandentalacademy.com
75
2. PRE-FORMED BANDS:
Band selection: Casts Variations – anatomy, tapered crowns, extra
cusps, restorations One size larger than the one that seems to fit
the tooth – prevents wasteful distortion of bands
www.indiandentalacademy.com
76
Band fitting:
First - finger pressure - only on mesial and distal sides Amalgam plugger / band pusher – 2/3rd Bite pressure through biting stick – facial and lingual Final seating pressure –
•Maxillary – palatal side of tooth•Mandibular – buccal side of tooth
www.indiandentalacademy.com
77
Checklist:
All cusps on banded teeth equally visibleBand margin –
•Just below marginal ridge•Above the contact point
Buccal attachment accurately positionedOpen occlusal margins crimped towards tooth
www.indiandentalacademy.com
www.indiandentalacademy.com 78
Thank you
For more details please visit www.indiandentalacademy.com