ABSTRACT:Background and objective:
Alveolar bone loss is a cardinal sign of periodontitis. Interproximal (bitewing) images more accurately record the crest of the interradicular alveolar bone because the beam is oriented at right angles to the long axis of the teeth, thus providing an accurate view of the relationship of the height of the alveolar bone through comparison with the adjacent teeth, however they tend to underestimate bone loss. It has been shown that the bone probing measurements is closely correlated with the actual bone level measured surgically and is the most reliable method for assessing bone levels before and after any surgical procedures. Hence the purpose of the study is to evaluate the diagnostic accuracy of digital bitewing radiographs in assessing alveolar bone level in comparison with transgingival probing.
Materials and methods: Sixty two subjects (age range 18-70 years, 34 males and 28 females) with chronic periodontitis were included. Radiographically alveolar bone level was measured by a single trained examiner using digital bitewing radiographs. Intraobserver correlation was done by intraclass correlation for radiographic data to avoid bias. Clinically transgingival probing was performed by a single trained examiner with stent in place using UNC 15 probe. The examiner was blinded to radiographic values to avoid bias. Results were statistically analyzed by paired sample t test, pearson’s correlation, intraclass correlation and regression methods.
Results: Intraclass correlation showed good reliability for radiographic measurements. Radiographic measurements showed consistently lower values compared to transgingival probing with an average underestimation of bone loss by 1.77 + 0.44 mm. Pearson’s correlation coefficient showed statistically significant correlation (r =0.960) between the two methods. As, there was a significant correlation between the two methods, a correction factor could be applied to estimate “Transgingival probing measurement” based on radiographic values with derived formula y=0.9668x+2.088 where y=Transgingival probing measurement, x= Radiographic measurement.
Conclusion: Radiographic measurements overestimated alveolar bone level ie, underestimated bone loss. However as there was a correlation between two methods, a correction factor could be applied to estimate transgingival probing values based on radiographic values.