Key Factors to Consider when Correcting the Vertical Dimension Flavia Artese
Principles of vertical management
· Deep bite – anterior intrusion and passive posterior extrusion
· AOB – posterior intrusion and anterior extrusion
TADs
· Anterior intrusion can affect smile aesthetics
· Posterior intrusion can effect function
Smile aesthetics
· Lombardi 1973
AOB management
· Consider smile line – usually inverted smile line
o Intrusion of 6s with TADs: clockwise rotation of maxilla = increase incisal show
o Incisor extrusion may be unstable, but a requirement for facial aesthetics
Deep bite management
· Consider smile line
o If consonant smile, intrusion of anterior teeth will flatten the smile
o 1mm of posterior extrusion = 3mm of anterior bite opening
o Incisor proclination
· Bite raising theory
o Posterior: high angle to avoid posterior extrusion
o Anterior: allow posterior extrusion
§ Flavia considers both result in premolar extrusion as arch levels
§ Flavia prefers anterior bite turbo as easier for patients to adapt to
§ Insufficient evidence on where to place bite raising appliances, Rathi 2021
Stability of intrusive / extrusive movements
· Posterior intrusion =: Maxillary molar relapse 12%, Mandibular relapse 27% Espinosa S/R 2020
· Posterior extrusion =Relapse 0-83% Huang 2012
Occlusal terms
1. Occlusal vertical dimension: Distance from nose to chin in maximum intercuspation
2. Rest vertical dimention: Distance from nose to chin in rest
3. Interocclusal clearance: Difference between above two tersm aka freeway space
Long term changes to occlusal vertical dimensions with bite raising
· 4.5-6mm increase, 2 year follow up, some relapse but overall increase OVD Liu 2018
Case erosive wear
· Class 2, reduced crown height, gastric reflux
· Treatment
o Refer gastroenterologist
o Restorative posterior increase in OVD
§ Results in greater class 2 relationship
· Class 3 attrition, reduced upper incisal show, lower incisors over-erupt
o Posterior molar extrusion with lower fixed and upper sectional appliances, and class 3 elastics increased OVD
o Intrusion of lower incisors with TADs
Retention
· Occlusal splint required for patients with OVD changes
OVD best evidence consensus paper Goldstein 2021
· Range of IOD 1-9.5mm
· RVD – little evidence, increase age = decrease muscle tone
· Alter OVD harmful? Depends on muscular adaptation, clinical evidence changes to OVD is stable
Conclusion
Functional changes to OVD, evidence is not clear and depend on adaptability and stability
Loss of posterior dimension: should be restored prior to orthodontics
Missing anterior tooth substance: should have orthodontics prior to restorative treatment
