Accuracy of digital intraoral periapical radiography and cone-beam computed tomography in the measurement of intrabony defects: A comparative study.

BACKGROUND: Periodontal disease is an inflammatory process resulting in clinical attachment loss (CAL), pocket depth (PD), and resulting in the loss of alveolar bone. Diagnostic imaging provides an adjunctive guidelines to assess the alveolar bone height in addition to clinical parameters such as PD and CAL. AIMS AND
OBJECTIVES: The objectives of the study are to determine whether the digital intraoral periapical (IOPA) radiographs can be reliably used as an alternative to cone-beam computed tomography (CBCT) in the diagnosis of intrabony defects.
MATERIALS AND METHODS: A total of 25 patients with the presence of intrabony defects were included in the study. All the radiographic parameters were recorded using digital IOPA and CBCT. Various intrabony defect morphological characteristics such as height, depth, width, and angle were measured and compared between digital IOPA and CBCT. STATISTICS: The data was subjected to statistical analysis. Mann-Whitney U-test was performed for interexaminer comparison and independent t-test for intergroup comparison.
RESULTS: The mean intergroup comparison values between digital IOPA and CBCT in relation to defect width were 3.22 ± 1.10 and 3.20 ± 1.16, respectively (P = 0.970), in relation to defect depth were 7.71 ± 2.3 and 7.91 ± 2.4, respectively (P = 0.769), in relation to defect height were 3.80 ± 1.20 and 3.90 ± 1.2, respectively (P = 0.794), and in relation to defect angle were 34.82 ± 8.4 and 35.28 ± 0.8.6, respectively (P = 0.851).
CONCLUSION: With the drawbacks of such as high radiation exposure, unavailability, and high financial cost, digital IOPA with digital software can be used as an alternative to CBCT for measuring intrabony defect morphological characteristics in periodontitis patients. Copyright:

INTRODUCTION

Periodontal disease is an inflammatory process resulting in clinical attachment loss (CAL), pocket depth (PD), and resulting in the loss of alveolar bone. One of the characteristic symptoms of destructive periodontal disease is the alveolar bone loss and this bone destruction pattern is divided into horizontal (even) and oblique (vertical/angular) bone defects. The bone destruction in vertical patterns does not proceed in a symmetrical pattern. The magnitude of bone destruction varies in different sites around the tooth, which explains why the crest of the alveolus does not correspond to the cementoenamel junction (CEJ), and it is not parallel to it. Hence for the diagnosis, treatment planning, and prognosis of intrabony defects evaluation of the defect morphology is crucial.[1]

Diagnostic imaging provides an adjunctive guidelines to assess the alveolar bone height as well as the occurrence of intrabone defects in addition to clinical parameters such as PD and CAL.[2] The precise methods for analyzing the morphological characteristics of the intrabony defects were clinical observation and topography.[3]

In the diagnosis of periodontal diseases, radiographs play a crucial role by depicting the nature and amount of injury that occurred to the alveolar tissues. For the diagnosis of the amount of alveolar bone loss and intrabony defect morphology, various intraoral and extraoral oral imaging modalities were available.[3]

Among the two dimensional (2D) intraoral imaging modalities, digital intraoral periapical (IOPA) radiographs and bitewing radiographs can be cheap, easily acquired, and provide high resolution images.[45] However despite of these advantages, 2 Dimensional imaging modalities are having limitations such as overlapping of anatomical structure and difficulties in standardization.[678]

To overcome the disadvantages of 2D imaging, cone-beam computed tomography (CBCT) (3D imaging) provides 3D analysis and rapid volumetric image in the field of diagnostic imaging, which include the elimination of distortions and the ability to visualize structures in all three orthogonal planes.[91011]

According to the literature, the use of digital IOPA had showed better results close to intrasurgical analysis, whereas 3D imaging showed an 80%–100% sensitivity in the detection of intrabony defects.[12]

Hence, the purpose of the study is to determine whether the digital periapical radiographs can be reliably used as an alternative to CBCT in the diagnosis of intrabony defects.

MATERIALS AND METHODS

The present study was conducted on 25 subjects, selected from the Department of Periodontology and Implantology, Teaching Institution. The Study Protocol was approved by the Institutional Ethical Committee. After explaining the procedure, written and informed consent was obtained from patients who are willing to participate in the study. A total of 25 patients diagnosed with chronic and aggressive periodontitis with the presence of intrabony defects were included in the study. All the radiographic parameters were recorded using digital IOPA and CBCT.

Study design

The patients were selected according to the following criteria:

Inclusion criteria

Patients should be in between 18 and 56 years of age

Patients diagnosed with chronic and aggressive periodontitis (localized/generalized)

Transgingival probing PD ≥6 mm and CAL ≥7 mm.

Exclusion criteria

Patients who were systemically compromised

Pregnant and lactating females

Patients who received periodontal treatment in the past 6 months.

Clinical examination was performed by postgraduates under the supervision of senior periodontist. Clinical attachment level (CAL) and trans gingival probing depth were taken.

IOPA was performed using the Scanora digital software (2.2) using the long-cone paralleling technique with a bite registration positioning device. The exposure setting was 70 kVp with 12–25 mA. The millimetric grid used for digital intraoral radiographs was composed of 1-mm copper squares. These squares were used to calibrate the measurement tool of the viewing software to compensate for the elongation and foreshortening of the image.

A CBCT imaging technique was performed on each patient (9300 CBCT, carestream dental). The exposure settings were 80 kV and 10 mA. The scanning parameters selected were 90 μm voxel size, 12 s acquisition time, and 5 cm × 5 cm field of view. The CS imaging software module (version 2.2, CS 9300, Carestream Health, Inc, 150 verona street, Rochester street, NY, USA, 14608) was used to reconstruct and reformat the volume and resulting slices and complete all measurements. The axial slices in CBCT were used to verify the presence of combined bony defects, according to the classification of Goldman and Cohen.

Radiological parameters

The height of the defect: Distance from the CEJ to the alveolar crest (AC)

Depth of the defect: Distance from CEJ to the base of the defect

Width of the defect: Highest point of the AC to the root adjacent to the defect

Defect angle: Two lines that represent the root surface of the involved tooth and the bone defect surface.[13]

Imaging evaluation

The images were analyzed by two examiners: a radiologist with 2 years of experience and examiner 2 was a third-year postgraduate student in periodontology.

Radiographic assessment was done by using Image Assistant software for periapical radiographs and CBCT according to Misch et al. At each site, three measurements were taken, they are as follows: (1) the height of the AC, measured from the CEJ to the AC, (2) the depth of the defect, measured from the CEJ to the bottom of the defect (BD), and (3) the width of the defect, measured from the highest point of the AC to the dental root adjacent to the defect. If restorations were present, the apical margin of the restoration replaced the CEJ as a fixed reference point. Defect angle was measured from the line drawing from the CEJ to the BD, and the other line extends from the BD to the lateral margin of the defect [Figures 1a-d and 2a-d].[7]

Figure 1

(a) Width of the defect on the mesial surface of 26 in cone-beam computed tomography; (b) Height of the defect on the mesial surface of 26 in cone-beam computed tomography; (c) Depth of the defect on the mesial surface of 26 in cone-beam computed tomography; (d) Defect angle on the mesial surface of 26 in cone-beam computed tomography

Figure 2

(a) Width of the defect on the mesial surface of 26 in digital intraoral peri-apical; (b) Height of the defect on the mesial surface of 26 in digital intraoral periapical; (c) Depth of the defect on the mesial surface of 26 in digital intraoral periapical; (d) Defect angle on the mesial surface of 26 in digital intraoral periapical

Interexaminer agreement was evaluated as the standard error of the mean difference of the measurements performed by each of the two examiners. These were <1. Ninety percent of the first examiner measurements were within the range of ± 3° relative to the values obtained by the second examiner. Images were interpreted by an experienced orofacial radiologist.

Statistical analysis

The data was subjected to statistical analysis. Mann–Whitney U-test was done for interexaminer comparison and independent t-test for intergroup comparison. P < 0.05 was considered as statistically significant.

RESULTS

The mean interexaminer comparison values for CBCT in relation to defect width between the two examiners were 25.40 and 25.60, respectively (P = 0.961). The mean interexaminer comparison values for CBCT in relation to defect depth between the two examiners were 25.58 and 25.42, respectively (P = 0.969). The mean interexaminer comparison values for CBCT in relation to defect height between the two examiners were 25.74 and 25.26, respectively (P = 0.907). The mean interexaminer comparison values for CBCT in relation to defect angle between the two examiners were 25.46 and 25.54, respectively (P = 0.984) [Table 1].

Table 1

Interexaminer comparison of cone-beam computed tomography

Examiner	n	Mean rank	Mann-Whitney U	P
Width
1	25	25.40	310.0	0.961
2	25	25.60
Total	50
Depth
1	25	25.58	310.5	0.969
2	25	25.42
Total	50
Height
1	25	25.74	306.5	0.907
2	25	25.26
Total	50
Angle
1	25	25.46	311.5	0.984
2	25	25.54
Total	50

Mann-Whitney U-test. P<0.05. n – Number of subjects; P – Probability value

The mean interexaminer comparison values for digital IOPA in relation to defect width between the two examiners were 25.54 and 25.46, respectively (P = 0.984). The mean interexaminer comparison values for digital IOPA in relation to defect depth between the two examiners were 25.52 and 25.48, respectively (P = 0.992). The mean interexaminer comparison values for digital IOPA in relation to defect height between the two examiners were 25.32 and 25.68, respectively (P = 0.930). The mean interexaminer comparison values for digital IOPA in relation to defect angle between the two examiners were 25.52 and 25.48, respectively (P = 0.992) [Table 2].

Table 2

Interexaminer comparison of intraoral periapical

Examiner	n	Mean rank	Mann-Whitney U	P
Width
1	25	25.54	311.5	0.984
2	25	25.46
Total	50
Depth
1	25	25.52	312.0	0.992
2	25	25.48
Total	50
Height
1	25	25.32	308.0	0.930
2	25	25.68
Total	50
Angle
1	25	25.52	312.0	0.992
2	25	25.48
Total	50

Mann-Whitney U-test. P<0.05. n – Number of subjects; P – Probability value

The mean intergroup comparison values between digital IOPA and CBCT in relation to defect width were 3.22 ± 1.10 and 3.20 ± 1.16, respectively (P = 0.970). The mean intergroup comparison values between digital IOPA and CBCT in relation to defect depth were 7.71 ± 2.3 and 7.91 ± 2.4, respectively (P = 0.769). The mean intergroup comparison values between digital IOPA and CBCT in relation to defect height were 3.80 ± 1.20 and 3.90 ± 1.2 respectively (P = 0.794). The mean intergroup comparison values between digital IOPA and CBCT in relation to defect angle were 34.82 ± 8.4 and 35.28 ± 0.8.6, respectively (P = 0.851) [Table 3].

Table 3

Comparison of various parameters between cone-beam computed tomography and intraoral periapical techniques

Group	Mean±SD	P
Width
CBCT	3.2080±1.16937	0.970
IOPA	3.2200±1.10980
Depth
CBCT	7.9160±2.40289	0.769
IOPA	7.7160±2.38357
Height
CBCT	3.9000±1.26820	0.794
IOPA	3.8080±1.20897
Angle
CBCT	35.2800±8.64831	0.851
IOPA	34.8240±8.45204

Independent t-test. P<0.05. SD – Standard deviation; IOPA – Intraoral periapical; CBCT – Cone-beam computed tomography; P – Probability value

DISCUSSION

To our knowledge, this was the first study to compare the intrabony morphological parameters between CBCT and digital IOPA techniques. The mean age of the patients included in this study was 35 years and there was an equal distribution of genders between the two groups.

The normal bone height in relation to CEJ ranges from 1 mm to 3 mm in patients without periodontal disease. The mean alveolar bone height in relation to CEJ For adults with mean age of 35 years was 1.4mm and it was in accordance with previous literature. Therefore, the mean alveolar bone height above 1.4 mm from the CEJ was considered as the level for the presence of periodontal disease.[14]

The results of the Mann–Whitney U-test for comparison between the measurements made by the two examiners showed P < 0.05 for all the measurements indicating that the scores were nonvariant for data collected by the examiners. The results demonstrate a high agreement between the two examiners, revealing good calibration and reliability of the results of the study.

In detection of the bone loss patterns, no statistical difference was seen between the two groups. Buccal and palatal/lingual surface measurements in axial section measurements were not compared due to consideration with limitations of periapical images. The agreement of the absolute measurement evaluation was made between the two examiners, P < 0.05 depicts that for the assessment of bone loss in both buccal and lingual/palatal surfaces, reliably cross-sectional slices can be used. An agreement in identifying vertical bone loss in 95% of the cases was present between the two examiners.

The results demonstrate a similar accuracy of periodontal bone level measurements when compared to Vasconcelos study.[13]

The delineation of lamina dura, bone quality, and contrast rating remains better for the digital intraoral images, which contain a higher resolution compared with CBCT.[12] The present study shows that there were no statistically significant differences observed in assessing bone level measurements in CBCT and digital intraoral radiographic techniques which were similar to the study conducted by Vandenberghe et al.[12]

With respect to width and depth of the defect, no statistically significant difference was observed, which is similar to Misch et al's study.[7] In contradiction to the present study, Mol and Balasundaram conducted a study on human skulls where they demonstrated that CBCT was slightly more accurate than intraoral radiographic techniques.[6]

Various authors had emphasized the importance of defect angle in the establishment of prognosis and calculating the amount of bone fill after intrabony defect treatment. For the determination of CAL gain in intrabony defects, radiographic defect angle can be used as a presurgical parameter when Guided Tissue Regeneration (GTR) was used for the treatment according to Cortellini and Tonetti.[15] Small defect angles (0–45) have greater defect fill potential in periodontal surgery when compared to wide angles (45–90) in the analysis done before the treatment phase.[1617] In the present study, the mean radiographic defect angles compared between CBCT and Digital IOPA were 35.28 ± 8.64 and 34.80 ± 8.4, respectively. No statistically significant difference between the two groups in preoperative assessment of defect angle was observed.

In this study, we found that the measurements of height, depth, and defect angle of vertical bone defect obtained by the two techniques were very close, and the difference in the measurements was not significant. The studies used defect angle at baseline with end treatment results in periodontal surgery by enamel matrix derivative and by using a DIA tool.[1819]

The limitations of the present study were small sample size and less duration of the study. As with CBCT, the presence of metallic restorations and high resolution is required for the study of intrabony defect morphological characteristics in periodontal diseases.

CONCLUSION

Radiographic defect angle plays a prominent role in assessing the prognosis of the intrabony defects in periodontal disease. Hence, presurgical measurement of these parameters is important and with the drawbacks of such as high radiation exposure, unavailability, and high financial cost, digital IOPA with digital software can be used as an alternative to CBCT for measuring intrabony defect morphological characteristics in periodontitis patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.