Evaluation of Dental Midline Relation to Some Landmarks of the Face and Mouth

Statement of problems: One of the first observation which should be considered in patients during the setting of anterior teeth is the relationship between the anterior teeth midline and the midline of the face. In situations, when the anterior teeth midline is not in favorite relation with the midline of the face, for the resean that the incisal plane of anterior teeth is not parallel with the interpupillary line, unpleasant teeth to face relationship will be present.

The purpose of this study was to determine a relationship between the midline of central incisors with some landmarks of the face and mouth to make use of them in full denture construction.

In this cross sectional descreptive study, 110 individuals including 85 males and 25 females with the mean age 21.5 years were selected. The inclusion creiteria were no extracted teeth, no orthodontic therapy and no esthetic surgery on the nose and face. After examining and completing the questionnaires, impressions were made of both arches using alginate impression material. After preparation of the casts, the relationship of both upper and lower teeth midline, upper central incisor midline to incisive papilla, the midline of filtrum, and labial frenum were examined and the results were recorded. Then the central and deviation parameters in population including average and variance in different percentages were compared.In 62.7% of individuals, the maxillary teeth midline was adapted with the center of incisive papilla. In 37.3% of individuals, the maxillary teeth midline was coincided with the philtrum. In the same percent of individuals, the maxillary teeth midline was at the same line with the upper lip frenum. In 10.9% of individuals, the mandibular dental midline was adapted with the maxillary dental midline. In 3.36% of individuals, the maxillary and mandibular dental midlines and philtrum were adapted.The results of this study showed that it would not be possible in most cases to construct complete dentures in which all landmarks of the face and mouth be coincided with the midline of the anterior teeth.