Identification of an Alternate Maxillary Apical Base Landmark from Pre-existing Substitutions

Cephalometrically the position of maxilla is usually assessed by point A, which is one of the most common cephalometric landmarks used for spatial analysis of maxilla, however in certain scenarios we require a alternative landmark.

In this study a nearest alternative maxillary apical base landmark was identified for Point A substitutions given by different authors.

A cross sectional study was conducted on thirty (30) good quality lateral cephalograms. Only those lateral cephalograms were selected where Point A was easily identified. Landmarks: Sella (S), Nasion (N), Point A and three substitution points Y, L, X were traced. Angles formed by SN with Point A (Angle SNA) and three substitution points (Angle SNY, SNX, SNL) were measured. Correlation of angle SNA with angles SNY, SNX and SNL were derived. Statistical analysis used.

Mean and standard deviation for Angles SNA, SNY, SNL and SNX were calculated individually for males and females. 'T' Test was applied to determine statistical significance for all the parameters i.e Age, Angles SNA, SNY, SNL and SNX respectively. Karl Pearson correlation coefficient was carried out to determine the statistical significant correlation for Angle SNA with SNY, SNL and SNX.

A mean value of 82.8° ±1.9°, 83.1° ±1.8°, 78.3° ±2.9° and 78.7° ±2.7° for Angle's SNA, SNY, SNL and SNX respectively was observed. A statistically significant correlation was observed between angles SNA & SNY, SNL, SNX & strong positive correlation was observed with angle SNY.

We conclude that Point Y is the most nearing maxillary apical base landmark to Point A. Hence maxillary apical base landmark can be substituted by Point Y where identification of point A is not obvious.