Use of lingual frenum in determining the original vertical position of mandibular anterior teeth

Abstract

Statement of problem. There is no accurate method for determining the correct vertical dimension of occlusion in edentulous patients. Preextraction diagnostic casts may facilitate determination of vertical dimension of occlusion. In the maxilla, the incisive papilla is a stable anatomic landmark and can be used as a guide to determine the vertical relation of the edentulous patient. Unfortunately, the mandible is devoid of such a stable anatomic landmark. Purpose. This study evaluated the reliability of measurement of the distance between the anterior attachment of the lingual frenum and the incisal edges of the mandibular incisors, on casts, to be used as a preextraction record for determining the vertical position of the mandibular incisors in complete denture patients. Material And Method. Eighteen dentate subjects (9 men, 9 women; 21-28 years; mean age 23 years) were selected. Four mandibular casts were made from irreversible hydrocolloid impression material in plastic stock trays for each subject. All subjects were instructed to elevate the tongue while the impressions were made. The vertical distance between the anterior attachment of the lingual frenum and incisal edges of mandibular central incisors was measured on the casts. Means and standard deviations of the 4 measurements were calculated and statistically analyzed. Results. The mean standard deviation of the distance between the anterior attachment of the lingual frenum and incisal edges of mandibular central incisors among the subjects was 0.1326 mm (coefficient of variation 1.292%). The distance between the anterior attachment of the lingual frenum and incisal edges of mandibular incisors was relatively stable when the frenum was recorded during function. Conclusion. The distance between the anterior attachment of the lingual frenum and incisal edges of the mandibular central incisors can be used on preextraction diagnostic casts as a preextraction record for determining the original vertical position of the mandibular anterior teeth. (J Prosthet Dent 1999;82:177-81.)