Radiology is essential in prosthodontics for diagnosis and treatment planning, utilizing intraoral radiographs, panoramic imaging, and cone beam computed tomography (CBCT) while adhering to the as low as reasonably achievable principle. CBCT provides 3 dimensional (3D) evaluations of bone quality, dimensions, and proximity to vital structures, aiding implant placement and reducing surgical risks. Artificial intelligence (AI) and computer-assisted surgery have transformed prosthodontics, improving treatment planning and implant precision and reducing complications. The future of prosthodontic radiology will increasingly integrate AI-driven imaging and robotic assistance to enhance precision and treatment success.
Key points
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Radiology is crucial in prosthodontics for evaluating oral and maxillofacial structures, aiding in the accurate placement of dental implants, and ensuring precise treatment planning while minimizing radiation exposure.
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Various imaging techniques, including intraoral radiographs, panoramic imaging, and cone beam computed tomography, are utilized at different stages of prosthodontic treatment to enhance diagnostic efficiency and patient care.
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The use of artificial intelligence and computer-assisted surgery has improved the accuracy and success rates of dental implant procedures by providing precise 3 dimensional imaging, enhancing treatment planning, and reducing complications.
Introduction
Radiology plays an indispensable role in dentistry and provides critical insights into the oral and maxillofacial structures. Prior to prescribing radiographs, careful consideration of the selection criteria and thorough clinical examination are imperative to ensure precise radiographic diagnosis while minimizing radiation exposure and costs. The landscape of modern dentistry has undergone profound changes owing to the widespread adoption of dental implants and the extensive utilization of cone beam computed tomography (CBCT). Recently, there has been a paradigm shift from a surgical to prosthetic perspective regarding dental implant placement. Currently, implant placement without comprehensive prosthetic restoration planning is deemed unsustainable. Clinicians must possess comprehensive knowledge of factors such as bone height/width, trabecular bone pattern, and nearby vital structures when planning implant procedures. , Different imaging modalities can help clinicians during different stages of treatment. In this study, we underscore the significance of various imaging modalities for prosthodontic treatment, with the aim of maximizing diagnostic efficiency, enhancing patient care, and minimizing posttreatment errors and complications.
Pretreatment anatomic site consideration
The alveolar bone varies by location due to differences in morphology, trabecular patterns, and adjacent structures. In the maxillary anterior region, postextraction residual ridge atrophy affects both height and width, often creating a labial concavity ( Fig. 1 ) that may require augmentation. Bone dimensions are also influenced by the nasopalatine canal ( Fig. 2 ) and nasal cavity floor. Implant placement in the anterior maxilla is also complicated by the canalis sinuosus (anterior superior alveolar nerve canal), especially in the lateral incisor and canine regions, where it parallels the nasopalatine canal ( Fig. 3 ). In the posterior maxillary region, the alveolar bone is adjacent to the maxillary sinus, making residual bone evaluation crucial ( Fig. 4 ). Low trabecular bone density increases implant failure risk. The maxillary sinus floor can cause alveolar bone pneumatization, potentially requiring sinus augmentation based on residual bone height.
Presurgical sinus assessment is essential to reduce complications, including evaluating sinus wall vascularization, ostiomeatal unit patency ( Fig. 5 ), cortices, septation ( Fig. 6 ), and the anterior recess ( Fig. 7 ). The maxillary sinus is vascularized by the infraorbital artery, the posterior superior alveolar artery (PSAA), and by the lateral nasal artery. The infraorbital artery and PSAA have both intraosseous and extraosseous anastomoses and branches in the lateral wall of sinus. It is essential to understand the location of the protruding infraorbital canal within the sinus lumen ( Fig. 8 ) and the posterior superior alveolar neurovascular canal in the lateral sinus wall ( Fig. 9 ) to prevent intraoperative arterial damage. ,
Although the anterior mandible is typically deemed safe for implants, evaluating anatomic structures is necessary to prevent bleeding, sensory issues, and to improve osseointegration. Important structures include the genial tubercle, lingual canal, mental foramen ( Fig. 10 ), terminal branch of the mandibular canal, and anterior loop of the mandibular canal ( Fig. 11 ). In the posterior mandible, implant placement can be complicated by structures such as the submandibular gland fossa, which forms a lingual concavity below the mylohyoid ridge ( Fig. 12 ), and the mandibular canal (see Fig. 11 ). ,
Fundamentals of radiology in prosthodontics
Prosthodontic patients may be completely or partially edentulous, or fully dentate, seeking improved esthetics and/or function. The advent of implant dentistry has changed the prosthesis option for completely and partially edentulous patient. For decades, dental implants have been utilized to restore chewing function by replacing missing teeth, and they have become a reliable treatment method for dental rehabilitation. This section explores how radiology aids in decision-making by helping clinicians understand the specific applications, advantages, and limitations of various imaging techniques used in prosthodontic treatment.
Intraoral Radiographs
Intraoral radiography, including periapical, bite-wing, and occlusal images, is commonly used in dental practices. Periapical imaging is frequently employed throughout prosthodontic treatment stages. For preoperative assessment, it evaluates osseous healing at edentulous sites and identifies retained roots, residual periapical pathology, and conditions such as dense bone island and cemento-osseous dysplasia (COD), which can complicate treatment. It also assesses adjacent teeth and estimates mesiodistal and vertical distances to anatomic boundaries and vital structures in partially edentulous patients. However, periapical images lack buccolingual dimension details and are susceptible to geometric distortion and magnification, limiting their utility for accurate linear measurements essential for preoperative implant planning. Vertical accuracy can be enhanced by using a radiographic marker of known dimensions to calibrate image measurements. Despite these limitations, intraoral radiography remains valuable for preliminary evaluation during intraoperative and postoperative phases.
Panoramic Imaging
Panoramic imaging offers a comprehensive view of the maxillofacial region and is preferred for its low cost and ease of acquisition. However, it has significant limitations, such as distortion, superimposition, and a lack of Three-dimensional (3D) capability. The degree of distortion is unpredictable and influenced by patient positioning and jaw alignment within the focal trough. Structures buccal to this trough appear distorted and narrow horizontally, while those lingual to the trough appear horizontally magnified. This nonuniform distortion prevents accurate mesiodistal measurements of the edentulous ridge and cannot be corrected by software. Additionally, vertical magnification of 15% to 30% occurs, and the negative vertical angulation of the x-ray beam results in a superior projection of lingually positioned structures. Despite these limitations, panoramic imaging is valuable for initial evaluations, especially either when assessing multiple sites simultaneously or when intraoral images are impractical due to challenging patient anatomy or lack of cooperation.
Cone Beam Computed Tomography
CBCT provides accurate, three-dimensional assessments of bone quantity, cortical plate thickness, trabecular bone quality, and proximity to adjacent anatomic structures. It is the preferred imaging method for the preoperative evaluation of the maxillary sinuses before sinus augmentation, assessment of donor and recipient sites for autogenous bone grafting, and assessment of procedure outcomes. Additionally, CBCT is crucial for designing and fabricating surgical guides using computer-aided design (CAD) and computer-aided manufacturing (CAM) technology. Like all ionizing radiation imaging techniques, CBCT should be used responsibly with careful protocols. The field of view should be restricted to the region of interest but may include relevant adjacent anatomy, such as the maxillary sinus ostia before sinus lifts, the external oblique ridges for bone harvesting, or opposing dental crowns for prosthetic planning and surgical guide fabrication. To ensure diagnostic quality with minimal radiation exposure, exposure settings should be adjusted based on the patient’s age, size, and anatomy, with efforts to minimize motion during image acquisition. ,
MRI
MRI in implant dentistry has multiple applications, including the planning, placement, and follow-up of dental implants, with effectiveness similar to CBCT. Techniques like Black Bone MRI and MSVAT-SPACE MRI minimize artifacts and enhance tissue resolution, serving as useful alternatives to CBCT. MRI also helps evaluate bone structure, dimensions, and proximity to vital structures, improving predictions of postoperative outcomes and reducing surgical risks. Furthermore, MRI is excellent for soft tissue visualization, minimizes radiation exposure, and enhances perioperative diagnostics by improving bone imaging and reducing metal artifacts.
Rationale for image use in prosthodontics based on radiation dose
By evaluating radiation doses among various imaging options, clinicians can select the optimal modality that offers necessary diagnostic information while adhering to the as low as reasonably achievable safety principle. This strategy minimizes patients’ radiation exposure and promotes safer imaging practices. CBCT radiation doses are lower than computed tomography (CT) and equivalent to 2 to 10 panoramic radiographs (20–100 μSv). However, there is significant variability among commercial CBCT systems, with doses ranging from about 10 to 1000 μSv, equivalent to 2 to 200 panoramic radiographs. , CBCT systems vary widely in parameters, causing significant differences in radiation dose and image quality. Although low-dose protocols are recommended and increasingly utilized, further research is required to optimize the balance between image quality and dose in implant dentistry. , While CBCT generally has lower radiation doses than CT, both deliver significantly higher doses compared to 2 dimensional imaging techniques. Thus, continuous dose optimization and customization remain essential for radiation safety and effectiveness.
Impact of parameters on image quality for prosthodontic applications
The image quality of CBCT devices can vary widely, influenced by exposure protocols and radiation dose. CBCT typically offers high spatial resolution, with voxel sizes ranging from 0.08 to 0.4 mm, which is useful for visualizing small structures. However, segmentation accuracy can vary, impacting the effectiveness of virtual planning and guide fabrication. A target accuracy of 200 μm is generally achievable, though inaccuracies up to 1000 μm can occur. Compared to multislice CT, CBCT often has lower contrast resolution, affecting segmentation and diagnostic capability. , CBCT also lacks distinct soft tissue contrast and does not use Hounsfield units, complicating bone density assessments and follow-ups. This makes CBCT less reliable for tracking bone density changes compared to medical CT. Instead, structural bone analysis through μCT software may be more relevant for assessing bone quality in implant dentistry. Additionally, CBCT images can suffer from artifacts due to patient motion or metallic restorations, affecting image quality.
Use of imaging in implant treatment planning
In 2012, the American Academy of Oral and Maxillofacial Radiology (AAOMR) released a position statement detailing the use of radiology in implant dentistry, with a particular emphasis on CBCT. The position statement offers evidence-based and consensus-driven clinical guidance for clinicians on the most suitable imaging techniques for dental implant therapy, with particular emphasis on CBCT, across different stages of the treatment process. The guidelines are as follows based on the treatment phase ( Table 1 ).
