Join me for Neal Kravitz’s lecture on canine substitution and the clinical management of it. Focusing on bracket selection and canine recontouring

Case selection

· 2 key factors

o Profile

o Mandibular crowding

Bracket selection

· Goal:

o Canine substitution:

§ Reduce canine root prominence

o Premolar substitution:

§ Hide palatal cusp

o Molar interdigitation:

§ class 2 cases

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)

o plasty and step out

· UR3 inverted (+7tq, +8 tip)

o Flipped U3

o Likely require addional torque

· LL5 inverted (+17 tq, +2 tip)

o Suggested by Marco Rosa

o 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

o Mesial IPR – Kailasam 2021 1.2mm enamel mesial

o Incisal reduction

o Palatal reduction

Interproximal reduction for Bolton’s discrepancy

Class 1

· Canine substitution with lower extractions = maxillary excess

o = IPR uppers to correct Bolton’s discrepancy (U 1, 3, 4)

Class 2

· Canine substitution, lower non-ext = Mandibular excess

o = IPR lower anterior to correct Bolton excess (U 1, 3, 4)

Cosmetic bonding

· Step 1: Mesial step out

o Improve marginal ridge with central

o Reduce occlusal interference lower arch

· Step 2: Mesial build up

o Mesial incisal

o 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

o Length of bonded retainer

§ Lower canine mid to distal lateral incisor labial measurement = lingual 3-3 measurement

o Material – memotain Custom NiTi

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.