A Comparison of the Accurate Diagnosis of the Horizontal & Vertical Bitewing Images in Detecting Approximal Caries and Interdental Bone Loss in Posterior Teeth: A Randomized Controlled Clinical Trial
Phase: NA
Conditions: Periodontal Diseases, Dental Caries
Sponsor: King Abdulaziz University

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A Comparison of Horizontal and Vertical 
Bitewing Radiographs in Detecting 
Approximal Caries and Interdental Bone 
Loss in Posterior Teeth: A Diagnostic 
Accuracy Randomized Cross-Over Clinical 
Trial 
NCT04341636 
February  20, 2020 
 
 
Principal Investigator: 
Dr. Zuhair S. Natto 
Departments of Dental Public Health and Periodontology 
King Abdulaziz University, Tufts University, Harvard University 
Co-Investigators: 
Anas Olwi, Faisal Abduljawad 
Faculty of Dentistry, King Abdulaziz University 
 
 

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1. Background and Rationale 
Bitewing radiographs are a standard diagnostic tool in dental practice, primarily used to detect 
approximal caries and evaluate interproximal alveolar bone levels. Traditionally, horizontal 
bitewings have been widely used for these purposes. However, they have limitations in 
visualizing vertical bone loss, furcation involvement, and root caries. 
Vertical bitewing radiographs, by contrast, provide greater visibility of the apico-coronal 
dimension and root structures, making them potentially more effective for diagnosing 
periodontal conditions and deeper carious lesions. This study aims to compare the diagnostic 
accuracy of vertical versus horizontal bitewing images in detecting caries and bone loss in 
posterior teeth. 
 
2. Objectives 
Primary Objective 
• 
To compare the accuracy of vertical versus horizontal bitewing radiographs in detecting 
approximal caries and alveolar bone loss. 
Secondary Objective 
• 
To evaluate the effectiveness of both imaging modalities in identifying furcation 
involvement. 
• 
To assess the diagnostic clarity and patient suitability for each radiographic approach. 
 
 
Material and methods: 
3. Study Design 
This is a two-arm, randomized crossover clinical trial comparing vertical and horizontal 
bitewing radiographs. The study was conducted at the Faculty of Dentistry, King 
Abdulaziz University. 

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Type of Study: Open-label, randomized crossover clinical trial 
Study Setting: Faculty of Dentistry, King Abdulaziz University 
Registration: ClinicalTrials.gov (NCT04341636) 
Ethical Approval: KAU Ethics Committee (#053-06-17) 
 
4. Participants 
Inclusion Criteria: 
• 
Age ≥18 years 
• 
Presenting for treatment at KAU dental clinics 
• 
Presence of posterior teeth and canines in each quadrant 
• 
No acute periodontal infection 
• 
Non-smokers 
• 
Full ability to open mouth and tolerate X-ray procedures 
Exclusion Criteria: 
• 
Systemic conditions complicating treatment 
• 
Pregnancy or lactation 
• 
Prosthesis obscuring CEJ or caries borders 
• 
Gag reflex or any contraindication to X-ray 
• 
Refusal to participate 
 
5. Interventions 
Each participant received: 
• 
Four horizontal bitewing radiographs (control) 
• 
Four vertical bitewing radiographs (experimental) 
• 
Radiographs were taken using a standardized film holder and a 3-mm orthodontic wire 
attached to the sensor for magnification calibration. 

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Observers included two restorative specialists (for caries) and two periodontists (for bone loss), 
all blinded to group assignments. 
 
 
6. Measurements 
• Caries Assessment: 
Evaluated using a 5-point diagnostic confidence scale and a secondary clarity scale. 
• Bone Loss & Furcation: 
Measured from the CEJ to the alveolar crest using calibrated software. Furcation 
involvement was assessed using a 5-point scale. 
• Intra- and Inter-Observer Agreement: 
Evaluated with Kappa statistics and intra-class correlation coefficients. 
 
7. Sample Size Calculation 
• 
Software: G*Power 3.1.9 
• 
Effect size: 2.1 mean difference 
• 
SD: 5.2 
• 
Power: 80% 
• 
Alpha: 0.05 
• 
Required Sample: 20 patients 
 
8. Statistical Analysis 
Statistical Analysis 
Software: 
Data will be analyzed using IBM SPSS Statistics version 23.0 (IBM Corp., Armonk, NY, USA) 
and ROC analysis will be performed using MedCalc or equivalent software for diagnostic 

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accuracy assessment. 
8.1 Analysis Population: 
All radiographs captured for the 20 enrolled participants (160 total bitewing images: 80 vertical, 
80 horizontal) will be included. Both intention-to-treat and per-protocol analyses will be 
conducted. All images were anonymized, and evaluators were blinded to image type and patient 
identity. 
 
8.2 Primary Analysis: 
Primary Endpoints: 
• 
Detection of approximal caries (presence and clarity) 
• 
Alveolar bone level measurements (in mm) 
• 
Presence and clarity of furcation involvement 
Tests for Diagnostic Accuracy: 
• 
Receiver Operating Characteristic (ROC) Analysis: 
ROC curves were plotted for each evaluator for both vertical and horizontal bitewings. 
The Area Under the Curve (AUC) was computed to assess diagnostic accuracy compared 
to the <gold standard= (combined clinical and radiographic diagnosis). 
o AUC values close to 1.0 indicate higher accuracy. 
o Comparisons of AUCs between vertical and horizontal bitewings were conducted 
using DeLong’s test. 
• 
Sensitivity and Specificity: These were calculated for each radiographic method in 
detecting caries and furcation involvement. 95% confidence intervals were provided. 
 
8.3 Observer Reliability: 
• 
Intra-Observer Agreement: Measured using Weighted Kappa coefficients for repeated 
readings of the same radiographs by the same observer at two time points. 

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• 
Inter-Observer Agreement: Measured using Intraclass Correlation Coefficient (ICC) 
for bone level measurements and Weighted Kappa for caries and furcation rating scores 
between observers. 
Interpretation of Kappa values: 
o < 0.20: Poor 
o 0.21–0.40: Fair 
o 0.41–0.60: Moderate 
o 0.61–0.80: Substantial 
o 0.81–1.00: Almost perfect 
 
8.4 Comparative Tests Between Vertical and Horizontal Bitewings: 
• 
Wilcoxon Signed-Rank Test: Used to compare the mean alveolar bone loss 
measurements (mesial, distal, and total) between vertical and horizontal bitewings (non-
parametric paired comparison). 
• 
McNemar Test: Applied to assess paired binary outcomes (e.g., presence vs. absence of 
caries or furcation involvement) between imaging modalities. 
• 
Chi-Square Test: Used to compare proportions of overlapping contacts and furcation 
detection in both modalities. 
• 
Descriptive Statistics: 
o Mean ± standard deviation (SD) for continuous variables (e.g., bone level) 
o Frequencies and percentages for categorical variables (e.g., tooth type, gender 
distribution) 
 
8.5 Handling of Missing Data: 
• 
Missing image evaluations (if any) were addressed via sensitivity analysis using pairwise 
deletion, given the minimal expected rate due to controlled data acquisition and blinded 

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scoring. 
 
8.6 Effect Size Reporting: 
• 
For Wilcoxon and McNemar tests, effect sizes (r) were reported. 
• 
For ROC analysis, 95% CI of AUCs and comparison P-values were provided. 
 
9. Expected Outcomes 
• 
Vertical bitewings will show higher sensitivity in detecting furcation involvement. 
• 
Vertical bitewings will provide better diagnostic accuracy for approximal caries and 
alveolar bone loss. 
• 
Vertical bitewings will have superior intra- and inter-observer reliability in detecting 
pathology. 
 
10. Ethical Considerations 
• 
All participants provided informed written consent. 
• 
Ethical approval was secured from local ethics board. 
• 
All data were anonymized and securely stored. 
• 
Participants had the right to withdraw at any time without consequences. 
 
11. Timeline 
Phase 
Duration 
Ethical Approval 
Completed 
Participant Recruitment 2 months 
Radiograph Collection 2 months 
Data Analysis 
1 month 

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Phase 
Duration 
Manuscript 
1 month 
 
12. Dissemination Plan 
The study results will be disseminated through: 
• 
Peer-reviewed publication 
• 
Scientific conferences 
• 
Institutional and ministry health updates 

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References 
1. White SC, Pharoah MJ. Oral Radiology: Principles and Interpretation. 7th ed. St. Louis: Mosby; 
2014. 
→ Standard textbook reference for radiographic principles and bitewing techniques. 
2. Hong RY, Kwon S, Steffensen B, et al. Diagnosing periodontal and dental indicators with 
horizontal and vertical bitewing radiographs. J Dent Educ. 2020;84(5):552–558. 
→ Direct comparison of diagnostic utility between vertical and horizontal bitewings. 
3. Hausmann E. A contemporary perspective on techniques for the clinical assessment of alveolar 
bone. J Periodontol. 1990;61(3):149–156. 
→ Foundational review on radiographic bone level assessment. 
4. Mol A. Imaging methods in periodontology. Periodontol 2000. 2004;34:34–48. 
→ Overview of imaging modalities for periodontal diagnosis, including vertical bitewings. 
5. Akarslan ZZ, Akdevelioğlu M, Güngör K, et al. A comparison of the diagnostic accuracy of 
bitewing, periapical, unfiltered, and filtered digital panoramic images for approximal caries 
detection in posterior teeth. Dentomaxillofac Radiol. 2008;37(8):458–463. 
→ Discusses bitewing effectiveness in detecting approximal caries. 
6. Zaki HA, Hoffmann KR, Hausmann E, et al. Is radiologic assessment of alveolar crest height 
useful to monitor periodontal disease activity? Dent Clin North Am. 2015;59(4):859–872. 
→ Supports radiologic monitoring of periodontal conditions. 
7. Ashwinirani SR, Suragimath G, Jaishankar HP, et al. Comparison of diagnostic accuracy of 
conventional intraoral periapical and direct digital radiographs in detecting interdental bone 
loss. J Clin Diagn Res. 2015;9(3):ZC35–ZC38. 
→ Supports digital methods in alveolar bone loss detection. 
8. Li G, Engström PE, Näsström K, et al. Marginal bone levels measured in film and digital 
radiographs corrected for attenuation and visual response: an in vivo study. Dentomaxillofac 
Radiol. 2007;36(1):7–11. 
→ Methodological support for using a calibration wire in bone loss measurement. 
9. Phinney DJ, Halstead JD. Dental Assisting: A Comprehensive Approach. Delmar Cengage 
Learning; 2012. 
→ Useful reference on basic bitewing procedures and positioning. 
10. Bollu P, Mardini S, Gohel A. Horizontal versus vertical bitewing radiographs in opening 
interproximal tooth contacts. Presented at the American Association of Dental Researchers; 
2008. Abstract 246. 
→ Early evidence comparing contact separation in bitewing orientations. 
11. American Academy of Periodontology. Proceedings of the 2017 World Workshop on the 
Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 
2018;89(Suppl 1):S1–S287. 
→ Periodontal staging guidelines that emphasize accurate bone level assessment.