Increasing Vertical Dimension of Occlusion (VDO): Review

Area of Science:

• Dental Science
• Prosthodontics
• Biomechanics

Background:

• Increasing the Vertical Dimension of Occlusion (VDO) is common in dentistry for functional restoration and treatment optimization.
• The traditional belief of a fixed Vertical Dimension at Rest (VDR) has limited the development of restorations encroaching on interocclusal rest space (IRS).
• Recent research indicates the mandible's rest position exists within a variable 'comfort zone'.

Purpose of the Study:

• To review the safety and predictability of increasing VDO in dental restorations.
• To explore the adaptive capacities of the masticatory apparatus to VDO changes.
• To provide guidance on the extent and methodology for VDO increases.

Main Methods:

• Literature review synthesizing current research on VDO, VDR, and masticatory adaptation.
• Analysis of patient adaptation mechanisms to altered VDO across different patient groups (dentulous, edentulous, implant-supported).
• Evaluation of factors influencing adaptation, including restoration type and extent of VDO increase.

Main Results:

• A permanent increase in VDO is a safe procedure for dentulous patients.
• Significant patient adaptation to increased VDO occurs through muscle relaxation and length changes.
• Fixed restorations facilitate more predictable and rapid adaptation compared to other methods.

Conclusions:

• Minimizing VDO increase to less than 5 mm inter-incisally is advisable for simpler treatment.
• The biological and functional environment demonstrates significant, historically underestimated, adaptive capacities.
• Temporary diagnostic restorations are crucial for assessing muscle adaptation before definitive prostheses.