Evaluation of Maxillary Dental Midline Alignment with Facial Landmarks in an Iranian Population

Background and Aim: Proper alignment of the maxillary dental midline is crucial for successful prosthetic rehabilitation and orthodontic treatment. This study investigated the alignment of the maxillary dental midline with three facial landmarks, the facial midline, philtrum, and nasal tip, in an Iranian population. Materials and Methods: Photographs of 608 randomly selected individuals were taken, each captured in a frontal view while smiling. A Nikon D5300 digital camera with a 105-mm lens was used, positioned 1.2 meters from the subjects. A metallic scale marked with millimeters was placed along the face in each photo to serve as a reference for resizing during later computer analysis. The distances between the maxillary dental midline and each facial landmark (facial midline, philtrum, and nasal tip) were measured using Adobe Photoshop software, and the data were analyzed with SPSS software. Data analysis was conducted using independent t-tests for group comparisons and paired t-tests for left-right directional comparisons. The significance level was set at 0.05 for all tests. Results: The alignment results revealed that the philtrum coincided with the maxillary dental midline in 3.3% of cases, the facial midline aligned in 1.6%, and the nasal tip showed only minor alignment with the dental midline. Conclusion: Significant differences were found in the alignment of the maxillary dental midline with the facial midline, philtrum, and nasal tip, with the highest alignment seen at the philtrum, followed by the facial midline and the nasal tip showing a minor alignment.