EPA Consensus Project Paper: The Vertical Dimension of Occlusion. How to Determine and How to Alter? A Systematic Review.

PURPOSE: The aim of this systematic review was to explore the dental literature to identify high quality clinical studies that introduced methods of determining the vertical dimension of occlusion (VDO), and additionally to find studies which assessed alterations in the VDO. MATERIALS AND METHODS: An electronic search of the literature was conducted through PubMed , Embase, and Cochrane Library databases referring to the determination and alteration of the VDO by 12/2021. RESULTS: A total of 215 records were obtained from the initial search. After the first two screenings, 33 studies were selected for inclusion. Correlations in the morphometric group ranged between r=0.18-0.87, p⟨0.05-0.001, correlations in the cephalometric group ranged between r=0.28-0.92, p⟨0.05-0.001, and correlations in the mechanometric group ranged between r=0.21- 0.75, p⟨0.05-0.01. Regarding the alteration of VDO, in all studies the increase ranged between 1.8-8 mm and the patients adapted . CONCLUSIONS: No clear guidelines can be established yet, in relation to the determination and alteration of the VDO. There is no apparent benefit in using more invasive and complex methods compared to the use of the facial anatomical landmarks. Patient adaptation seems to be successful when the range of VDO increase was 1.8-6.0 mm.

An anthropometric study to evaluate the correlation of vertical dimension at rest and length of thumb: A multi-national, multi-centre pilot study.

AIM: A variety of anthropometric techniques have been proposed to determine the correct vertical dimension of occlusion. However, none have reported correlating thumb length (TL) with vertical dimension at rest (VDR). This study aimed to correlate the VDR to measurements of the thumb in a multi-national, multi-centric trial in participants with and without orthodontic treatment and establish a regression equation for each region. SETTINGS AND DESIGN: A cross-sectional multi-national, multi-centric correlation trial. MATERIALS AND METHODS: A cross-sectional study was conducted in India and Malaysia with a total of 688 participants. Measurements of thumb and VDR were obtained using a modified Willi's gauge using a standard operating procedure. STATISTICAL ANALYSIS USED: Pearson's correlation coefficient was calculated to determine the correlation between TL and VDR. A multiple linear regression was done to correlate VDR from gender, orthodontic treatment, and length of thumb. RESULTS: Correlation coefficient between TL and VDR in patients with orthodontic treatment was 0.829 and 0.774 in patients without orthodontic treatment. The correlation between TL and VDR in patients with orthodontic treatment in North India was 0.484, P = 0.010 and Malaysia was 0.946, P < 0.001. There were significant correlations between TL and VDR in patients without orthodontic treatment in all regions (P < 0.001). Regression equations were obtained for different ethnic groups for calculating the VDR. CONCLUSION: There was an overall positive correlation between TL and VDR in patients with and without orthodontic treatment. The regression equations presented in this article could help clinicians in their clinical practice and researchers to conduct future trials.

Freeway space determination using lateral profile photographs: A pilot study.

STATEMENT OF PROBLEM: Many methods are reported in literature to determine freeway space (FWS), but they yield dissimilar measurements. PURPOSE: Recording FWS of patients during prosthetic rehabilitation is one of the important steps in dentistry. The purpose of this study is to evaluate the ability to predict FWS using lateral profile photographs (LPPs) in edentulous participants. MATERIALS AND METHODS: Fifty-three participants in the age range of 20-27 years who met the inclusion criteria were recruited. LPP were taken for all participants using standard protocol and duplicate copy obtained; on which three soft tissue reference points, porion (Stp), gnathion (Stgn), and gonion (Stg) (Stg prenoted on the face) were marked and joined to form an angle Stp-Stg-Stgn. This angle was correlated with the mean FWS obtained using 3 methods, swallowing, phonetics, and no command. Simple linear regression model was used to develop a prediction formula for FWS using Stp-Stg-Stgn angle as the independent variable. RESULTS: The angle Stp-Stg-Stgn had a significant negative correlation with FWS (r = -0.76, P < 0.001). Using simple linear regression analysis, the following formula was obtained: FWS (in millimeters) = 11.405 - 0.072 × (Stp-Stg-Stgn angle in degrees). CONCLUSION: Within the limitations of this study, considering the usage of LPP as a method to determine the FWS can be recommended.

Reliability of different facial measurements for determination of vertical dimension of occlusion in edentulous using accepted facial dimensions recorded from dentulous subjects.

The study was undertaken to evaluate the reliability of different facial measurements for determination of vertical dimension of occlusion in edentulous subjects using accepted facial dimensions recorded from dentulous subjects. The hypothesis was that facial measurements can be used to obtain the vertical dimension of occlusion for edentulous patients where no pre-extraction records exist. A total of 180 subjects were selected in the age groups of 50-60 years, consisting of 75 dentate male and 75 dentate female subjects for whom different facial measurements were recorded including vertical dimension of occlusion and rest, and 15 edentulous male and 15 edentulous female subjects for whom all the facial measurements were recorded including the vertical dimension of rest and occlusion following construction of upper and lower complete dentures. The left outer canthus of eye to angle of mouth distance and the right Ear-Eye distance were found to be as valuable adjuncts in the determination of occlusal vertical dimension. The Glabella-Subnasion distance, the Pupil-Stomion distance, the Pupil-Rima Oris distance and the distance between the two Angles of the Mouth did not have a significant role in the determination of the occlusal vertical dimension. The vertical dimension can be determined with reasonable accuracy by utilizing other facial measurements for patients for whom no pre-extraction records exist.

Comparative evaluation of vertical dimension at rest before extraction, after extraction and after rehabilitation with complete denture - A Cephalometric study.

INTRODUCTION: The determination of physiologic rest position of the mandible to the maxillae is of paramount importance in almost all fields of dentistry. The stability of vertical dimension at rest has been controversial if the rest position of mandible remains constant throughout life or not. Despite of several studies on the rest position of the mandible and facial vertical dimension, certain fundamental disagreements remain unresolved. The present study aims to compare the vertical dimension at rest, before and after extraction and after rehabilitation with complete denture. MATERIAL & METHODS: This study was conducted in a total of ten randomly selected patients, who had some natural teeth present with one or more opposing posterior teeth with vertical occlusal stops but were advised for extraction because of poor prognosis. Digital lateral cephalograms were done and measurements recorded at three stages: prior to extraction of remaining natural teeth, post extraction and after complete denture rehabilitation. RESULTS: Vertical dimension at rest was found to be greatest in post rehabilitation followed by pre-extraction than post extraction state. The differences in changes were found to be statistically significant. CONCLUSION: Vertical dimension at rest shows a decrease following extraction of natural teeth, the occlusal stops, and an increase on rehabilitation. It can be stated that vertical dimension at rest is not stable position and varies following extraction of natural teeth and rehabilitation.