Occlusal Vertical Dimension: Best Evidence Consensus Statement

Purpose: Patients in need of extensive prosthodontic treatment may need restoration of their occlusal vertical dimension (OVD) due to tooth wear, tooth loss, or changes that have occurred to existing prostheses over time. Prosthodontic treatment is based on the clinical application of the available evidence regarding interocclusal distance (IOD), the positional stability of rest vertical dimension (RVD), and the effect of altering the OVD. Hence, the purpose of this consensus document is to examine available data related to IOD, RVD, and alteration of the OVD. Materials and Methods: The search was limited to Clinical trials, Randomized Controlled Trials, Systematic Reviews and Meta-analyses. Key words were healthy patient, mean, range, interocclusal rest distance; healthy patient, mean, range, freeway space; and dentistry, interocclusal gap, and no citations appeared. Dentistry, interocclusal distance, revealed 5 not relevant citations. Dentistry, inter occlusal rest space, and dentistry, interocclusal rest distance, both had the same single not relevant citation. Dentistry, freeway space revealed over 7,000 citations. Dentistry, occlusal vertical dimension, revealed 253 citations, 7 of which were related to the search question but only 1 which was different from the previous search. Mandible, rest vertical dimension, age changes, found 7 citations, none relative to the question. Expanding the search to include journal article found 260 citations with only one relevant to the question. Mandible, rest vertical dimension, alteration, harm revealed no citations; mandible, occlusal vertical dimension, alteration, revealed 15 citations, 1 of which was relevant; mandible, occlusal vertical dimension, changes, revealed 75 citations, none of which were relevant; mandible, occlusal vertical dimension, rehabilitation revealed 10 citations, none of which were relevant. Expanding the search strategy to include Journal article, mandible, occlusal vertical dimension, alteration, received 159 citations, 4 of which were relevant; mandible, occlusal vertical dimension, restoration revealed 208 citations, 1 of which was relevant. Numerous other articles were culled by going through the reference lists of the aforementioned articles. Results: For IOD, 27 articles were found relevant to the search question, which confirmed a mean of 3.0 mm with ranges from 1 to 9 mm. Five articles revealed little evidence as to whether the RVD changes during life. For OVD, 20 articles, including 4 systematic reviews, revealed some evidence that skeletal growth continues from mid adolescence into mid adulthood; strong anecdotal evidence that some unopposed teeth will continue to erupt; no clinical evidence to support the concept that abraded teeth in occlusion in a patient with bruxism will undergo continuous eruption; and some evidence from clinical case reports that restoring OVD in patients with severe abrasion is a successful treatment. Conclusions: There is a range of dimensions for the interocclusal distance (IOD) with many normal dental patients functioning with a higher or lower IOD than the commonly used 3.0 mm average dimension. The resting vertical dimension (RVD) is a 3-dimensional range with little evidence related to changes in the RVD during life. However, aging can cause a decrease in muscle tone which could affect the RVD. The restoration of the OVD can be successfully accomplished if proper diagnosis and treatment planning are performed.