G. A. V. M. Geerts, MchD,a M. E. Stuhlinger, BChD,b and D. G. Nel, DScc School for Oral Health Sciences, University of Stellenbosch, Tygerberg, South Africa Statement of problem. Measuring vertical dimension is a soft-tissue measurement. Therefore, inaccuracy may
Purpose. Thepurpose of this study is to compare the accuracy of the Willis gauge method with the caliper
Material and methods. The Willis gauge measures the distance between the septum of the nose and the chin.
The caliper method measures the distance between reference points on the tip of the nose and the chin. Twenty predoctoral students applied both methods 10 times in measuring the rest verticaldimension (RVD) and the occlusal vertical dimension (OVD) of a single edentulous patient. The measurements obtained from one experienced clinician were selected as controls for the interocclusal distances (IOD) for the Willis and the caliper methods, respectively. One-sided t tests and a 1-sided nonparametric test were used to determine signiﬁcant differences between the 2 methods ( .05). Results.The variances in the RVD values for the Willis gauge method were higher than for the caliper method for most students. A Wilcoxon signed rank test showed that the accuracy of the OVD measurements for the caliper method was signiﬁcantly better than for the Willis gauge method (P .001). This was not the case for the RVD measurements (P .073).The average IOD for the Willis method was signiﬁcantlyhigher than the control IOD (P .026). The average IOD for the caliper method was not signiﬁcantly larger than the control (P .1303). Conclusion. This study showed that the use of the caliper method by predoctoral students was a signiﬁcantly more reliable method of measuring the OVD for the patient evaluated. (J Prosthet Dent 2004;91:59-66.)
The variation of the OVDmeasurements was signiﬁcantly smaller for the caliper method than for the Willis method as measured by predoctoral students. The difference between the IOD for the Willis gauge and for the caliper methods was not signiﬁcant.
he determination of the occlusal vertical dimension (OVD) is an important procedure in the treatment of the edentulous patient.1-4 Adequate interocclusal distance (IOD) is associatedwith daily use of complete or removable partial dentures.5 Incorrect determination of the OVD and centric relation may result in failure of complete denture treatment.6 Many methods to determine a vertical dimension for the rehabilitation of edentulous patients are described in the literature.7-12 These methods include the use of physiologic rest position,2,13,14 phonetics,2,15-18 esthetics,19swallowing,19-22 craniometrics,23-27 cephalometrics,28-32 and electromyography.33-36 However, there is no single precise scientiﬁc method for determining the correct OVD for the edentulous patient.3,7,20,24,26,31,37 Some authors
Presented at the XXXVI South African and the XVI East and Southern African Divisions Joint Scientiﬁc Meeting of the IADR, Durban, South Africa, August 2002. a AssociateProfessor and Chairperson, Division of Prosthodontics. b Lecturer, Division of Prosthodontics. c Professor and Director of the Centre for Statistical Consultation. JANUARY 2004
prefer the concept of a “zone of comfort,” a “vertical comfort range,” or a “preferred vertical dimension of occlusion.”38-42 Many dentists use the physiologic rest position as a starting point.23 In order to establishthe physiologic rest position, several authors recommend a combination of techniques.4,7,17,43-46 Different methods exist for measuring vertical dimension in physiologic rest position and maximum intercuspation. When selecting a method, the following criteria have been recommended: accuracy and reliability of the measurement, adaptability of the technique, type and complexity of equipment...