1. Bonding involves cleaning the enamel, conditioning it using acid, and applying adhesive resin to chemically bond brackets. Proper moisture control and enamel pretreatment are important for achieving optimal bond strength. 2. Various adhesive materials like composite resins, glass ionomer cements, and self-etching primers are used. Different light curing sources help polymerize the adhesives. Trays can aid in accurate bracket placement. 3. Debonding requires carefully removing brackets and cleaning residual adhesive to minimize enamel damage. Daily fluoride and good oral hygiene help prevent decalcification during treatment. Polishing can remove superficial discoloration when remineralization is exhausted.

1. Presenter: Dr. Aisha Khoja
Resident, Orthodontics

2. BONDING: The method of fixing attachments directly
over the enamel using adhesive resins
• Cleaning
• Enamel conditioning
• Sealing
• Bonding

3. • Pumice prophylaxis
• Removes plaque and organic pellicle
Literature review
Lill Dj et al, compared the pumice group Vs non pumiced teeth
on bond strengths and monitored for bond failures in 3 months
• Out of 508 teeth, thirty-five failures (6.9%) were recorded, with
6 (2.4%) in the pumice group and 29 (11.4%) in the non
pumice group
• However, Lindauer SJ et al didn’t find any significant
differences in rate of bracket failure between two groups
( Lindauer et al, 1997)
Lill DJ et al. Importance of pumice prophylaxis for bonding with self etch primer. Am J
Orthod Dentofacial Orthop. 2008:133;423-6

4. 1. MOISTURE CONTROL
• Lip expanders and cheek retractors- Dri-Angles
• Saliva ejectors
• Tongue guards
• Cotton or gauze rolls
• Antisialogogues- methantheline (15 min before bonding)

5. 2. ENAMEL PRETREATMENT
• Etching : 37% orthophosphoric acid for 15-30seconds
10% maleic acid, polyacrylic acid (weak SBS)
Laser etching ( can’t achieve standard etching
pattern)
• Etching removes 3-10 microns of surface enamel
• Washing and drying: for 5-10 seconds
• Etched surface: dull white frosty, honey comb appearance
• Saliva contamination should be avoided
• Blood contamination requires re-rinsing and drying (
protective liquid polish e.g. Bicover)
• Sandblasting ( Air-abrasive technique) - low SBS (shear
bond strength)
• Sandblasting + acid etching = comparable or higher SBS

7. 2. ENAMEL PRETREATMENT
• Enamel Deproteinization
- Acquired pellicle covering the surface of enamel is biofilm free
of bacterial colonization
- Composed of proteins, glycoproteins, enzymes and mucins
- make it difficult for composite to adhere to tooth enamel
diminishing SBS
- Use of 5.25% sodium hypochlorite for 60 seconds as a
deproteinizing agent before etching give good results (Justus
et al, 2010)
- Enamel deproteinization with 10% papain gel increases the
shear bond strength
Matheus Melo Pithon et al. Effect of 10% papain gel on enamel deproteinization before bonding
procedure. Angle Orthod. 2012;82:541–545.

8. • Thin layer of bonding agent- gentle air burst for 1-2
seconds
• Functions: - To achieve proper bond strength
- Improve resistance to micro leakage
• Moisture-Insensitive primers ( hydrophilic primers)
• Difficult moisture control situation
• Self etching primers
• Combine conditioning and priming (e.g. Transbond)
• Active ingredient: methacrylated phosphoric acid
ester
• Chemical bond: hybrid layer of 3-4 microns
• Improve chair side time efficiency, cost effective
• Bond strength is lower than the conventional

9. Adhesive under bracket base after
removal of H3PO4 etched enamel
(Honey comb appearance)
Adhesive under bracket base
after removal of Self etching
primer

10. ADHESIVE MATERIALS
• Composite resins
• Acrylic resins : methyl methacrylate monomers + ultrafine
powder
- Form linear polymers
- Suitable for plastic brackets
• Diacrylate resins: acrylic modified epoxy resins BIS-GMA
- Form crosslinking network
- Increase strength, less water absorption and less
polymerization shrinkage
- Suitable for metal brackets

11. ADHESIVE MATERIALS
• Glass ionomer cements
- Introduced primarily as luting agent and direct restorative
material
- Resin modified glass ionomer cement- 10% HEMA ( Fuji-
Ortho)
• Advantages
- Flouride release lessen decalcification around brackets
- Chemically adhere to enamel and bracket base
- Easier to remove after debonding (Norevall et al.,1995)
• Disadvantages
- Bond failure rate was 24.8% than composite resin failure rate
of 7.4% ( Matthew et al, 1999)
Matthew Gworski et al. Decalcification and bond failure: A comparison of a glass ionomer and
a composite resin bonding system in vivo. Am J Orthod Dentofacial Orthop 1999;116:518-21

12. • Polymerization from dimethacrylate resin monomer is never
complete
• Monomers identified in orthodontic composites:
• BISGMA
• TEGDMA
• UDMA
• HEMA
• Necrosis of pulp: Depletion of glutathione, production of
reactive oxygen species
• Precautions
- Amount of composite resin should be kept at minimum
- Excess (flash) should be removed before the resin
polymerize
- Ask patient to spit or wash their mouths for first 30 min (
monomer release is maximal)

13. TYPES OF ADHESIVES
• No mix adhesive
• Light-Polymerized Adhesives
- Curing: activation of photo initiator e.g.
Camphoroquinone
- Extended working time
- Bond strength are comparable to the chemically cured
composite (Swartz ML. 2004)
- Metallic and ceramic pre-coated with light cured
composites becoming popular
- Recent innovations: light activated color change
adhesives (APC Plus.3M/Unitek)

14. LIGHT SOURCES:
• Conventional halogen lights (Ortholoux XT)
- Maximum absorption in blue region of visible light (470nm)
- Curing time: 20 sec for composite resins
40 sec for RM-GIC
- Inconvenient for patient
• High intensity halogen lights (fast halogens)
- Increase light intensity with wavelength ( 400-505nm)
- Turbo tips to focus into small area
- Reduce curing time almost half to conventional bulbs

15. LIGHT SOURCES
• Plasma arc sources
- Tungsten anode and cathode in quartz tube filled with xenon
- Provide light intensity of 1200-1500 mW/cm2 and wavelength
of 380-495nm)
- Curing time: 3-5 sec for metal brackets and even shorter for
ceramic brackets ( Sfondrini et al. 2004)
- High heat generation can possibly harm the pulp tissue (
5.16°C vs 1.86°C for halogen bulbs)
• Light Emitting Diodes (LED’s)
- Small, cordless, generate minimal heat, perform favorably
- Curing time: 10sec for metal and 5 seconds for ceramic

16. • Plastic brackets
- Acrylic, Polycarbonate
- Used for esthetic reasons
- Lack strength, prone to breakage, uptake of water, need for
compatible bonding resin, can’t transmit torque
- Used in cases of minimal force situations, short duration
treatments
- Polycarbonate brackets with metal reinforced slots: less creep
than although torque problems still exist

17. • Metallic brackets
- Stainless steel, gold coated, titanium
- Rely on mechanical retention ( mesh guaze)
• Ceramic brackets
- Machined from monocrystalline or polycrystalline aluminium
oxide
- Combine esthetics of plastic and strength of metallic brackets
- Bonding: mechanical retention via undercuts in base
chemical bonding via silane coupling agent

18. • Ceramic brackets
Disadvantages
- Greater friction resistance between wire and ceramic
brackets (steel slots inserts are more reliable)
- More prone to breakage/ brittle
- More difficult to debond (wing fractures)
- Attracts more plaque and less hygienic

19. • Requires micro etching of these surfaces using 50um white or
90um tan aluminium oxide particles at 7kg/cm2 pressure
• Bonding to Ceramic crowns
- Sandblasting- 50um aluminum oxide for 3 seconds
- Etching- 9.6% HF acid for 2 minutes
- Rinsing and Drying
- Etched porcelain: frosty appearance

20. Bonding to Amalgam
• Small amalgam restorations
- Sanblasting: 50um aluminum oxide for 3 seconds
- Conditioning enamel- 37% phosphoric acid gel for 15 seconds
- Sealant, Bond as usual
• Large amalgam resorations
- Sandblasting: 50um aluminum oxide for 3 seconds
- Use of intermediate resins ( metal primer, All-Bond2) for 30
sec or adhesive resins that bond chemically( 4-META)
- Sealant and bond as usual

21. Bonding to Gold
• In vitro:
- High bond strengths
- Sandblasting, electrolyte tin plating
Clinically: not frequently encountered
Bonding to Composite
- Remove the previous old surface with rotary instrument

22. Tray Preparation
• Impression taking
• Work model preparation
- Isolate model with separating medium
- Bracket placement with proper angulations
• Transfer try
- Material: putty silicone, thermoplastics, polysiloxane
- Soak model in warm water as long as it takes to dissolve lab
adhesive
- Sandblast adhesive bases with micro-etching unit
- Use acetone to remove separating media

23. • Bonding
- Enamel conditioning
- Apply intermediate resin on the tooth surface and adhesive on
each individual bracket
- Seat the tray with equal pressure to occlusal, buccal and labial
surface
- Allow 2 minutes curing time
- Remove excess flash

25. Advantages
• Reduce chair side time
• More accurate positioning of brackets
• Advantageous for lingual bonding
Disadvantages
• Technique sensitive
• Removal of excess adhesive is difficult
• Risk of adhesive leakage in interproximal areas disturb oral
hygiene
• Bond failure rate is higher

26. • Removal of adhesive from the bracket base completely
without damaging or weakening its backing or distorting slot
Methods:
• Heat (about 450°C) to burn off the resin
• Electro polishing to remove any tarnish or oxide buildup
• Recycling has dropped off now (less than 10% orthodontists
use it)

27. Steps in Debonding
• Bracket removal
• Residual adhesive cleaning
Bracket Removal
• Steel brackets
- Peeling force technique ( placing the tips of twin-beaked pliers
against mesial and distal edges of bonding base)
- Break occur at bracket adhesive interface leaving remnant on
enamel
- Shearing forces should be avoided

28. Bracket Removal
• Ceramic brackets
- More likely to cause enamel fracture
- Risk is low with mechanical retentive than chemically retentive
ceramic brackets
- Recent brackets: mechanical lock base and vertical slot
reduces risk of bracket fracture
- Grinding with low speed handpiece without water coolant may
cause permanent damage or necrosis of pulp
• Recent innovations:
- Thermal debonding and lasers: heating and softening of
composite resin

29. Residual Adhesive Cleaning
• Methods
- Use of handpiece with tungsten carbide bur (30,000rpm)
- High speed handpiece with diamond bur
- Scraping with sharp band or bond removing pliers
• Scarring of enamel after debonding is inevitable
• Fine fluted tungsten carbide burs used with high speed, with
light brush stroke in one direction is most fastest, least
damaging method
Phillip M, Campbell. Enamel surfaces after orthodontic debonding. Angle
Orthodontist. 1995;65:103-110

30. • ENAMEL TEAROUTS
• Type of filler particles used in adhesive
- Small filler particles reinforce the enamel tags (fill 3-5microns
holes)
- Macro fillers create natural break point between enamel-
adhesive interface
- Unfilled resins: no natural break point
• Location of bond breakage
- Should be at enamel-adhesive interface (mechanical
retention)
- Break at adhesive-bracket interface: more damage (chemical
retention)

31. • ENAMEL CRACKS
• Generally are not visible on intra oral photographs
• Fiber optic transillumination
According to Zachrisson et al,
• Vertical cracks are most common (50%)
• Few horizontal and oblique cracks
• More noticeable cracks on maxillary central incisor and canine

32. ENAMEL CRACKS
Clinical Implication
• Pre-treatment examination of cracks and its documentation
• Inform patient if pronounced cracks are visible
• Observe cracks after debonding
• Detect any horizontal cracks- bonding/debonding technique
needs improvement
• Gentle manipulation of debonding instruments

33. • Daily rinsing with dilute (0.05%) sodium fluoride during
treatment and retention period
• Fluoride dentifrices
• Fluoride varnish in decalcified areas
• Oral hygiene measures

34. • Technique used to remove superficial enamel opacities,
brown-yellow enamel discoloration, when re mineralizing
capacity is exhausted
• Abrasive gel = 18% HCL, fine pumice and glycerin
Procedure:
• Isolate gingiva with rubber dam
• Gel is applied using electric tooth brush for 3-5 minutes
• Rinse for a minute
• Procedure can be repeated 2-3 times/month

35. Always make the care of your patient your first concern
“People don't care how much you know, until they know how much
you care!!” John C. Maxwell