Case selection
- 2 key factors
- Profile
- Mandibular crowding
Bracket selection
- Goal:
- Canine substitution:
- Reduce canine root prominence
- Premolar substitution:
- Hide palatal cusp
- Molar interdigitation:
- class 2 cases
- Canine substitution:
4 bracket choices for canine
- UR1 (+17 tq, + 4 tip)
- Achieves ideal torque
- Requires flattening of canine labial face = plasty
- UR2 (+10 tq, + 8 tip)
- plasty and step out
- UR3 inverted (+7tq, +8 tip)
- Flipped U3
- Likely require addional torque
- LL5 inverted (+17 tq, +2 tip)
- Suggested by Marco Rosa
- Same torque but no reduction labial face – compound contour
Upper 1st premolar bracket selection
- U3 or U4 slightly distal – palatal cusp hidden
- See orthoinsummary blog on Premolar substitution
Upper molar tube selection for class 2 finish
- Achieve good interdigitation, the U6s tubes have 10 degree rotation labially, which does not interdigitate with the lower 5/6 embrasure space well, the 0 degree offset on lower 6s / 7s (-20 / -10 torque)
- No change in tip and torque
Tooth reshaping
- Canine morphology frequently triangular, more so mesial then distal
- Reduction – frequently underdone
- Mesial IPR – Kailasam 2021 1.2mm enamel mesial
- Incisal reduction
- Palatal reduction
Interproximal reduction for Bolton’s discrepancy
Class 1
- Canine substitution with lower extractions = maxillary excess
- = IPR uppers to correct Bolton’s discrepancy (U 1, 3, 4)
Class 2
- Canine substitution, lower non-ext = Mandibular excess
- = IPR lower anterior to correct Bolton excess (U 1, 3, 4)
Cosmetic bonding
- Step 1: Mesial step out
- Improve marginal ridge with central
- Reduce occlusal interference lower arch
- Step 2: Mesial build up
- Mesial incisal
- Line angle not that I practice it but they are essentially
- Transition between proximal and labial face
- Can make canine look narrower through altering this transition, ie the shallower gradient narrower the tooth
Retention and review
- Group function and lateral clearance
- Long term fixed retention 4-4
- Length of bonded retainer
- Lower canine mid to distal lateral incisor labial measurement = lingual 3-3 measurement
- Material – memotain Custom NiTi
- Length of bonded retainer
References
Rosa, M.A.R.C.O. and Zachrisson, B.U., 2001. Integrating esthetic dentistry and space closure in patients with missing maxillary lateral incisors. Journal of Clinical Orthodontics, 35(4), pp.221-238
Kokich Jr, V.O. and Kinzer, G.A., 2005. Managing congenitally missing lateral incisors. Part I: Canine substitution. Journal of esthetic and restorative dentistry, 17(1), pp.5-10.
Kravitz, N.D. and Shirck, J.M., 2017. Measuring Bonded Lingual Retainers. Journal of clinical orthodontics: JCO, 51(5), pp.294-294.
Kravitz, N.D., Miller, S., Prakash, A. and Eapen, J.C., 2017. Canine bracket guide for substitution cases. J Clin Orthod, 51, pp.450-453.