Missing teeth and bony deficiencies. Exploring Dilemmas and Dogma. SOS. Mark Wertheimar. Part 1. Episode 20. July 30th 2020

Part 1

Mark explains the dilemmas and dogmas behind hypodontia management.

Dogma / idea influence opening vs closing

1. Canine guidance
   • Dogma: Canine guidance better than group function
     • Only evidence of negative affects relate to canine inclination, when tucked in = greater muscular activity, seems to relate to degree of freedom in occlusion Sugimoto 2011
   • Dogma: Proprioception from canine essential / special
     • Some have considered the proprioception of canines to be essential in the reflex arc of chewing.
     • However the ‘special’ proprioception not been shown to be of consequence.

SR on occlusal schemes: Abduo 2015

• Neither canine vs group function occurs naturally
• Occlusal schemes are dynamic
• Neither scheme pathological or therapeutic
• Crucial factor = degree of freedom in occlusion Sugimoto 2011

2. Implants:

• Idea / dogma: Implants are ideal prosthesis / without risk

1. Infraposition of implant – vertical growth of adjacent teeth and dentoalveolus, result in relative infaocclusion / position of implant
   • Between age of 10-30 = infraposition phenomenon of implants more obvious than 30-40 Schwartz-Arad 2015
   • Ideal age of implant placement varies
     • Delay until growth complete to prevent infraposition of implant assessed through serial radiographs

2. Implant problems
   • Tooth wear, loss of contact points Papageorgiou 2018 SR
   • 5-10% implants fail LONG TERM Pablos 2019

Timing of orthodontic treatment

• Idea / dogma: treat hypodontia patient at the usual age i.e. adolescence with 2 stages
  • In between stages the following can occur: risk of root change, boney changes -most significant is of spaces are greater than 6mm = likely to require bone augmentation in 60-80% of cases Bertl 2017
• One should delay to treat in single phase or space closure  Beyer 2005

Literature consistent

• Nordquist 1975 – Silveira 2016 SR, supporting space closure better aesthetics, periodontal outcomes, and no TMD.

Lay people perception

Prefer space closure Qadri 2016

References

Abduo, J. and Tennant, M., 2015. Impact of lateral occlusion schemes: A systematic review. The Journal of prosthetic dentistry, 114(2), pp.193-204.

Sugimoto, K., Yoshimi, H., Sasaguri, K. and Sato, S., 2011. Occlusion factors influencing the magnitude of sleep bruxism activity. CRANIO®, 29(2), pp.127-137.

Silveira, G.S., de Almeida, N.V., Pereira, D.M.T., Mattos, C.T. and Mucha, J.N., 2016. Prosthetic replacement vs space closure for maxillary lateral incisor agenesis: a systematic review. American Journal of Orthodontics and Dentofacial Orthopedics, 150(2), pp.228-237.