Join me for a summary of Dalia El Bokle’s lecture exploring finishing in orthodontics. Part 2 focuses on indirect bonding, a step by step process from model analysis to clinical delivery
Mark position on models
Intersection of horizontal and vertical lines
· Posterior teeth
o Vertical line: Long axis using OPG buccal, occlusal and lingual
o Horizontal line x 2
§ 1/ Marginal ridge line (outcome of treatment)
§ 2/ Slot line (position of bracket, depending on bracket system 2mm from marginal ridge line
§ Start with 1st molar
§ Measure cusp to slot line using gauge distance marginal ridge to slot line
§ Mark slot line for rest of the teeth, using the difference in height from marginal ridge to slot line from the 1st molar measurement
§ Ensure gauge is used perpendicular to the teeth
· Anterior teeth
o Vertical line: Draw long axis using OPG, labially and lingually
o 1/ Horizontal line start with canine
§ Slot line marginal ridge level distal canine and mesial 1st premolar
§ Position canine mesial to the long axis
o 2/ Lateral = bracket gauge of the canine to tooth tip, 0.25mm more cervical or same as canine if lateral small
o 3 / Central – add 0.25-0.5mm than canine
§ = subtle smile arc
Transfer tray
· Intersection of long axis to slot line – mark with wax knife
o Mark where brackets should go
· Tacky Glue to stick bracket to the model – water soluble glue, remove excess with probe
o Tip – use loupes / magnifying lens
· Allow set for 10 minutes
· Check occlusally, vertically and tip
o Digitally check glue is set
o Marginal ridge to slot line should be consistent
o Visualise tooth movement
· Relieve over the bracket hooks – wax or Tachy glue
· Vacuum forming machine
o 1mm soft sheet
· Check brackets have not moved – check vertical and horizontal lines
· Trim excess retainer material
· Soak 10 minutes, wash with water and interdental brush (ensure mesh of brackets clean)
· Slits from the gingival aspect of the retainer to the gingival aspect of the bracket
o Purpose is to expose the hooks of the brackets – difficult to remove when bond, aiming to uncover the hook from the retainer
· Wax placed under the hooks – prevent composite
· Section the tray if significant crowding
Clinical bonding IDB
· Etch bracket surface only – looking at model of the tooth
· Composite (light cure)
o Small quantity on mesh base of each bracket
o Microbrush to cover all surface and imbed into bracket mesh base
· Bond
· Seat IDB tray
o Apply perpendicular pressure on each bracket with scaler
§ Avoids excessive composite on the bracket base
· Light cure 20 seconds each tooth
· Remove tray – from palatal aspect from distal molar
· Flash removal
Trouble shooting
· Bracket off
o Don’t panic!
o Maintain isolation
o Remove excess composite, sharp scaler
o Trim tray
o Replace bracket in tray and re-insert transfer tray
· Bracket positioning incorrect
o Defective impression
o Bracket not glued well on model
o Defective vacuum forming
o Ensure no drags
Disadvantage of IDB
· Extra lab time
o 1 hour lab time
§ However reduced time in treatment and repositions / bends
o Extra cost
§ $12 if in house
o Excess flash
o Technique sensitivity
§ Multiple check points
o Accuracy
§ In Dalia’s opinion more accurate than direct bonding
