Assessment of linear measurements with intra oral grid on intra oral periapical image – A comparison of digital and conventional film images using bisecting angle and paralleling techniques

Abstract

Background: The success of various treatments protocols depends on pre-operative diagnostic aids such as radiographic assessment with linear measurements, in such scenario radiographic grid with its unique design aids like a scale for image analysis on intraoral periapical radiograph. Hence, the intra oral grid is a simple and accurate way of measuring objects, and another advantage is to overcome various magnification errors associated with measurements. So, the present study was designed to know its accuracy in assessing the linear measurements. Materials and Method: The study sample comprised a total of 40 subjects, which were categorized into four groups. A total of 240 exposures were taken, where each patient was subjected to six radiographs, of which two are conventional intraoral periapical radiographs without grid, and two are conventional intraoral periapical radiographs with grid by bisecting and paralleling technique and another two radiographs are taken by digital CMOS sensor with intraoral periapical grid in all four groups. The measurements were performed on the radiographs using scale and divider and in case of radiograph with the grid by counting the grid lines from specific points. Results: The results of the study revealed on comparison of conventional and digital radiographs with and without a grid in both bisecting and paralleling technique in all the four groups, there was a statistically significant difference noticed with digital radiography compared to the conventional method in assessing the measurements with the grid with P value <0.005. Similarly, paralleling technique showed a significant difference in its mean measurement values in all the four groups compared to bisecting angle technique in both conventional and digital methods in case of usage of grid. Conclusion: Intraoral grid was used as a scale in the instances where the exact size of various anatomical structures and pathologies cannot be determined visually in radiograph and even in cases of distortion; this can be used for standardization.

Keywords

• bisecting angle technique
• conventional and digital image
• intraoral grid
• iopa
• linear measurements
• paralleling technique