Vertical Dimension in Prosthodontics Theory and Practice (Part III): Contemporary Clinical Protocols and Decision-Making for Loss of Vertical Dimension of Occlusion

Loss of vertical dimension of occlusion (VDO) is among the most clinically significant presentations in prosthodontics and restorative dentistry. Despite its profound impact on orofacial function, esthetics, masticatory efficiency, and oral health-related quality of life, no universally accepted operational definition, diagnostic threshold, or treatment protocol currently exists. This narrative literature review aimed to review the contemporary evidence on the clinical protocols and decision-making in the rehabilitation of patients with VDO loss. This comprehensive narrative review was conducted in accordance with the Scale for the Assessment of Narrative Review Articles (SANRA) reporting principles. PubMed/MEDLINE, the Cochrane Library, Scopus, and Web of Science were searched from inception to October 2025 using combinations of Medical Subject Headings (MeSH) and free-text terms including "vertical dimension of occlusion", "tooth wear", "erosive tooth wear", "bruxism", "occlusal rehabilitation", "Dahl concept", "occlusal veneers", and "full-mouth rehabilitation" with emphasis on systematic reviews, longitudinal cohort studies, and randomized clinical trials. The review identified that VDO loss arises from a multifactorial etiological spectrum encompassing pathological tooth wear (erosion, attrition, abrasion, abfraction), tooth loss with posterior support collapse, parafunctional behaviors, iatrogenic factors, and systemic and pharmacological contributors. Population-based data indicate that the prevalence of severe tooth wear rises from approximately 3% at age 20 to 17% by age 70. Diagnosis remains predominantly empirical and integrative, triangulating anthropometric, phonetic, functional, and esthetic indicators - none of which is independently reliable. Digital diagnostic technologies offer measurable improvements in precision but remain insufficiently validated for standalone clinical use. Treatment philosophies span minimally invasive additive composite protocols (Dahl concept, three-step technique), indirect bonded ceramic rehabilitations (lithium disilicate, zirconia, ultrathin occlusal veneers), and full-arch tooth- or implant-supported reconstructions, with growing consensus around staged, reversible, and patient-centered decision-making. The contemporary management of loss of VDO requires a structured, individualized, and evidence-based approach. Clinical decisions should consider the underlying cause, the patient's ability to adapt, functional and biomechanical needs, and a stepwise plan that starts with reversible procedures before moving to definitive treatment.