📰 Comparative Efficacy of Digital Dental Imaging Modalities in Lesion Detection: A Review
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| Attributed to: THW Insights | health.web.id |
Abstract
Dental Care and diagnostic imaging has evolved from traditional film to highly detailed digital and volumetric methods. This review critically assesses the diagnostic efficacy (measured primarily by sensitivity and specificity) of key dental radiography techniques: Intraoral Periapical (PA), Bitewing (BW), Panoramic (OPG), and Cone-Beam Computed Tomography (CBCT). Our analysis emphasizes how the inherent geometric properties of each modality dictate its clinical utility and ultimate accuracy across prevalent dental diseases, advocating for an evidence-based approach to image selection guided by the ALARA principle.
1. Introduction: The Foundation of Dental Diagnosis
Accurate lesion identification is foundational to effective dental and endodontic care. The choice of imaging technique significantly influences the probability of correctly identifying a pathology (True Positive) while minimizing false findings (False Positive). We examine the performance characteristics of 2D (PA, BW, OPG) versus 3D (CBCT) imaging across three primary diagnostic areas.2. Efficacy in Proximal Caries Identification
Detecting early interproximal enamel or dentin lesions is the most common radiographic application.
Bitewing Radiography (BW): The Bitewing technique remains the gold standard for proximal caries. Its nearly parallel beam projection minimizes geometric distortion and overlap, affording the highest spatial resolution and diagnostic yield among 2D methods for these specific lesions.
Panoramic (OPG) Limitations: Conversely, the OPG is deemed unreliable for caries screening. Its low resolution, magnified image, and significant superimposition (overlap of structures) result in markedly lower sensitivity, leading to a high rate of missed lesions (False Negatives).
CBCT Role: While offering superior visualization, especially for recurrent or occlusal caries hidden beneath existing restorations, the routine deployment of CBCT solely for caries detection is generally discouraged due to the increased radiation dose.
3. Accuracy in Assessing Periapical Pathosis (Bone Lesions)
The evaluation of inflammatory periapical lesions (PLs) highlights a critical divergence between 2D and 3D modalities.
Periapical (PA) and the 2D Threshold: The Periapical radiograph is the first-line choice, but its two-dimensional nature necessitates a substantial loss of bone mineral (estimated 30-50%) before a radiolucency becomes evident. Consequently, PA has limited sensitivity for small or early PLs, particularly those confined to the buccal or lingual cortical plates.
CBCT Superiority: Cone-Beam Computed Tomography (CBCT) excels in this domain. By eliminating anatomical noise and superimposition, CBCT achieves near-perfect sensitivity (often cited as 100%) in visualizing the true extent and volume of PLs. CBCT is the preferred method for assessing complex endodontic treatment failures or presurgical planning.4. Comparison in Periodontal Bone Loss Quantification 📏
Accurate assessment of alveolar crestal bone height is essential for diagnosing periodontitis.
Optimal 2D Technique: Vertical Bitewing radiographs provide the most accurate 2D representation of marginal bone loss as they allow for precise visualization of the relationship between the CEJ (Cementoenamel Junction) and the bone crest without projection errors common in oblique PA shots.
CBCT for 3D Metrics: CBCT offers the definitive, distortion-free method for measuring both vertical and horizontal bone defects. Crucially, it is the only modality capable of accurately quantifying bone loss on the non-visible buccal and lingual/palatal aspects, providing the complete picture of the defect morphology.
5. Conclusion: Choosing the Right Tool
The selection criteria must prioritize the highest diagnostic yield at the lowest radiation dose
For high-prevalence, detail-intensive tasks like caries screening, BW is the most efficient.
For assessing localized areas of pain or endodontic concerns, PA is the initial standard.
For conditions where 2D projection is demonstrably inadequate—such as identifying small PLs, complex root anatomy, or detailed 3D bone defects—CBCT is the superior, albeit higher-dose, diagnostic instrument. Clinicians must judiciously integrate the statistical evidence (high AUC values in CBCT for PLs vs. high sensitivity in BW for caries) into their decision-making process.
Summary and Clinical Implication
| Modality | Primary Clinical Focus | Relative Accuracy | Radiation Dose (Relative) |
| Bitewing (BW) | Interproximal Caries, Marginal Bone Loss | Highest (2D) for Caries | Lowest |
| Periapical (PA) | Periapical Lesions, Root Integrity | Good, but Lower Sensitivity for PLs than CBCT | Low |
| Panoramic (OPG) | Comprehensive Overview, Impacted Teeth | Lowest for fine detail (Caries, PLs) | Moderate |
| CBCT | Complex PLs, Implant/Surgical Planning | Highest (3D) for Bone and Lesion Morphology | Highest |
Technique Diagnostic Dental Radiography
PERIAPICAL RADIOGRAPHY
Periapical radiography is a type of intraoral radiography that aims to see the entire crown and root of the tooth (crown and root), alveolar bone and surrounding tissue. Periapical radiographs have several uses, namely to detect periapical infection or inflammation, assessment of periodontal status, trauma involving teeth and alveolar bone, unerupted teeth, unerupted tooth condition and location, assessment of root morphology before extraction, endodontic treatment, pre-assessment. surgery and post-apical assessment, more accurate evaluation of radicular cysts and other alveolar bone lesions and post-implantation evaluation.
Periapical Radiograph Taking Technique. There are two techniques for taking periapical radiographs, namely: parallel technique and bisecting.
1. Parallel Technique
The parallel technique, also known as extension cone paralleling, right angle technique, long cone technique, true radiograph is the most accurate technique in making intraoral radiographs. This is because the parallel technique is very easy to implement and standardize with good image quality and small distortion. The parallel technique is achieved by placing the film parallel to the long axis of the tooth and then the film holder is placed to keep the film in place remain parallel to the long axis of the tooth. The x-ray center is directed perpendicular to the tooth and the film. Parallel technique when done correctly will produce images with good quality, high validity, linear accuracy and high dimensions without distortion. The advantage of the parallel technique is that it is without distortion, the resulting image is very representative of the real teeth, has high validity, the relative position of the image receptors so it is useful for some patients with disabilities. The disadvantage of the parallel technique is that it is difficult to place the film holder, especially in children and patients who have a small mouth, the use of the film holder on the surrounding tissue causes discomfort in the patient, and positioning the film holder on the lower third molars is very difficult.
Angle of parallel engineering of maxillary teeth:
- In shooting the maxillary central incisor the film is placed on the film holder in a vertical orientation. The film is placed on the palatal area so that the long axis of the tooth is parallel to the film. If the film is too close to the teeth, the image will be distorted. The beam should be perpendicular to the plane of the film and the film should be at an angle of 90 ° to the interproximal area of the maxillary central incisor. The center of the x-ray is focused on the tip of the nose. The radiographs to be obtained are mesial, distal, and apical of the maxillary central incisor.
- When shooting the maxillary lateral incisors the film is placed on the film holder in a vertical orientation. Angle of irradiation using the same angle to the maxillary central incisors. Film centered on behind the lateral incisors, perpendicular to the long axis of the lateral incisors. The center of the x-ray is centered on the tip of the nose. The radiographs that will be obtained are mesial, distal and apical lateral incisors, central incisors and canines.
- In shooting the maxillary film canine is placed on the film holder in a vertical orientation. The canine is placed in the center of the film on the palate. The center of the x-ray is perpendicular to the film and at a right angle to the long axis of the tooth. The center of the x-ray is focused on the corner of the nose or alanasi. The radiographic images to be obtained are mesial and apical canines.
- In shooting the film maxillary premolars are placed on the film holder in a horizontal orientation. The contact between the first and second premolars is centered on the film with the center of the x-ray perpendicular to the film. The center of the x-ray is below the pupil of the eye. The radiographic images that will be obtained are crown and apical from the distal canine, first, second premolar and first molars.
- shooting the film maxillary molars are placed on the film holder in a horizontal orientation. The second molar is located in the center of the film with the center of the x-ray perpendicular to the film. The center of the x-ray is below the outer corner of the eye to the middle area ofthe cheek. The radiographic images to be obtained are crown and apical of the first, second and third molars.
Angle of parallel engineering of mandibular teeth:
- On the anterior image of the mandible the film is placed on the film holder in a vertical orientation. The mandibular central incisor is located in the center of the film with the center of the x-ray perpendicular to the film. The center of the x-ray is under the tip of the nose to the center of the chin.
- In shooting the mandibular canine the film is placed on the film holder in a vertical orientation. The mandibular canine is located in the center of the film with the center of the x-ray perpendicular to the film.
- In shooting the mandibular premolar the film is placed on the film holder in a horizontal orientation. The contact between the second premolar and the first molars is in the middle of the film. The center of the beam must be perpendicular to the long axis of the tooth. The center of the x-ray is in the apical area of the tooth concerned about one cm above the base of the mandible. The film should contain radiographs from the distal canine to the mesial of the second molar, with the exposed premolar in contact.
- In the shooting, the film mandibular molars are placed on the film holder in a horizontal orientation. The center of the beam must be perpendicular to the long axis of the tooth. The center of the x-ray is in the apical area of the tooth concerned about one cm above the base of the mandible. Be careful with film placement as the sharp edges can cause discomfort to the sensitive floor of the mouth.
Bisecting technique is another technique that can be done besides the parallel technique in filming periapical films. Bisecting technique is commonly used in cases of anatomical abnormalities such as large palatine torus, narrow palate, shallow floor of the mouth, short frenulum, narrow arch width or in pediatric patients who are less cooperative. The film is placed into the oral cavity and a bite block is applied to hold the film. Bisecting technique is achieved by placing the receptor as close to the tooth as possible and placing the film along the lingual / palatal surface of the tooth then the x-ray is directed perpendicularly (T shape) to an imaginary line dividing the angle formed by the long axis of the tooth and the plane of the film. However, the bisecting technique produces less than optimal images because the receptors and teeth are not vertically x-rayed. This technique requires operator sensitivity and precision. If the bisecting angle is not correct, an extension or shortening will occur. The advantage of the bisecting technique is that it can be used without a film holder and is a comfortable position for the patient. The disadvantages of the bisecting technique are easy distortion and angulation problems (lots of angulation to be aware of). A standard cone measuring eight inches long can be used in the bisecting technique. If the radiographer wishes to use a long cone, the length of the long cone will be between twelve and sixteen inches (12-16 inches). The advantage of using a long cone is that it reduces the enlarged image and reduces distortion
BITEWING RADIOGRAPHY
The word bitewing comes from a radiographic retrieval technique that asks the patient to bite a kind of small wing that is attached to an intraoral film. Modern film holders have stripped the wing part, but the terminology and clinical indications still use the same term. This radiography was first introduced by Raper in 1925. Bitewing radiography was used to detect caries in the proximal surface of teeth and crest alveolar bone in both maxilla and mandible on the same film, which was clinically undetectable.
Bitewing (interproximal) radiographs are used to evaluate the interproximal bone crest during periodontal examinations and treatment plans. In the bitewing technique, the film is placed parallel to the crown surface of the maxillary and mandibular teeth. Then the patient is instructed to bite the bitewing tab or bitewing film holder and the x-ray is directed between the contacts of the teeth at a vertical angle of + 5 ° to + 10 °. The film can be positioned horizontally or vertically depending on the area to be radiographed. Vertical retrieval is commonly used to detect bone loss whereas horizontal retrieval is commonly used to view the crown, alveolar crest, cavity and the success of the treatment outcome.
One film can be used to examine the teeth in the upper and lower jaw at the same time. Bitewing radiography was used to view the line from the CEJ (cementoenamel junction) in one tooth to the CEJ of a neighboring tooth in the same film, as well as the distance from the crest to the interproximal bone present. Apart from being used to detect interproximal caries, bitewing radiographs also provide periodontal status information. The height from the interproximal edge of the alveolar bone to the relative cemento-enamel junction can be observed. Subgingival calculus deposits can also be detected. However, the results of bitewing radiographs in the diagnosis of periodontal disease were limited to the portion of the root crown of the teeth observed, and were limited to the molar-premolar region.
Bitewing Radiograph Retrieval Technique
Choose a film size that fits the patient.
A.Large film packets (31 x 41 mm) for adults.B.Small film packets (22 x 35 mm) for children under 12 years.
C.Occasionally a longer film packet (57 x 26 mm) for adults.
- The patient is positioned with a horizontal head tube and occlusal plane.
- Check the denture shape and the amount of film to be used. The operator holds the tab with the thumb and forefinger then inserts the film into the lingual sulcus opposite the posterior tooth.
- The anterior edge of the film is positioned distal to the mandibular canine and the posterior portion of the film lies in the mesial portion of the third molar.
- The tab was placed on the occlusal surface of the mandibular teeth.
- The patient is asked to close the teeth together with the tab.
- When the patient closes the teeth, the operator presses the tabs between the teeth to ensure the film and teeth are in contact, then the operator releases the tabs.
- The process of taking radiographs is carried out, after completion of processing it is carried out in a dark room.
Panoramic radiography or orthopanthography / OPG
Panoramic radiography or orthopanthography / OPG provides an overview of the facial structures including the maxillary arch, mandible, and other supporting structures, and is useful for detecting general patterns of bone loss.
The advantages of panoramic photos include:
- Gives a broad picture about facial bone structure and teeth.
- The radiation dose to the patient is relatively low.
- The patient is relatively comfortable during the examination.
- Can be used for patients who are unable to open their mouths.
- The time it takes for an X-ray is relatively short (3-4 minutes).
The disadvantages of panoramic photos include:
- The resulting images are incapable of presenting the anatomical details as on an intraoral radiograph.
- Often geometric distortion occurs.
Cycle diagram of the stages of forming a panoramic radiograph
Panoramic Radiograph Taking Techniques
- Insert the extraoral film (usually 15 x 30 cm in size) into the cassette. This procedure must be done in a dark room.
- Instruct the patient to remove any worn jewelry, hair clips, dentures or orthodontic devices.
- Describe the procedure for taking radiographs and the movement of the X-ray plane to reassure the patient.
- Have the patient wear an apron.
- Place the patient accurately on the x-ray plane using head positioning devices and X-ray source markers. Ensure that the patient's occlusal plane is positioned correctly.
- Instruct the patient to position the mandible anteriorly (prognathy) so that the occlusion of the patient's teeth in the anterior region is edge to edge.
- Instruct the patient to swallow and place the tongue against the roof of the mouth (so that it comes into contact with the hard palate).
- Place the film that has been included in the cassette in the cassette holder.
- Close the room door and press the X-ray airplane button.
- After taking the radiographs, do the processing in a dark room.
- Le Fort I
- Le Fort II
- Le Fort III
Reverse-Towne Projection Radiography
Submentovertex Radiography
