13.Radiographic imaging in implant dentistry.pptx

Radiographic

1. GUIDED BY- PRESENTED BY- Dr. ASHISTARU SAHA Dr. POOJA AGRAWAL Dr. SUDHEER ARUNACHALAM Dr. TUSHAR TANWANI Dr. ANUPAM PURWAR Dr. NEHA NAVLANI Dr. RUCHI GUPTA Dr. SUDEEPTI SONI RADIOGRAPHIC IMAGING IN IMPLANT DENTISTRY

2. Introduction Imaging objectives Imaging modalities- Periapical radiography Digital radiography Occlusal radiography Cephalometric radiography Panoramic radiography Computed tomography Magnetic resonance imaging Imaging of Vital structures Conclusion References CONTENT

3. Imaging plays an important part in dental implant procedures. The imaging modalities vary from standard projections routinely available in the dental office to more complex radiographic techniques typically available only in radiology centers . INTRODUCTION

4. Imaging modality is useful in three phases of treatment. Phase 1: Pre-prosthetic implant imaging Imaging in this phase determines the quantity, quality , and angulation of bone; relationship of critical structures to prospective implant sites; and the presence or absence of disease at the proposed surgical sites. Imaging Objective

5. Phase 2: Surgical and interventional implant imaging Imaging in this phase evaluates the surgical sites during and immediately after surgery. Assists in the optimal positioning and orientation of dental implants, and ascertains the healing and integration phase of implant surgery. It also ensures appropriate abutment positioning and prosthesis fabrication.

6. Phase 3: Post-prosthetic implant imaging This phase commences just after placement of the prosthesis and continues as long as the implant remains in the jaw. Imaging in this phase evaluates the long-term change, if any, in the implant's fixed position and function, including the crestal bone levels around each implant, and evaluates the status and prognosis of the dental implant. It also helps to routinely assess the bone adjacent to the dental implant to note any changes in mineralization or bone volume.

7. The goals of imaging are : To measure bone height and width (bone dimensions) To assess bone quality To determine the long axis of alveolar bone To identify and localize internal anatomy To establish jaw boundaries To detect any underlying pathology. While selecting the radiographic modality for the patient recommended principle is the ALARA Principle. “ As Low As Reasonably Achievable”

8. Periapical radiography Panoramic radiography Occlusal radiography Cephalometric radiography Conventional tomographic radiography Cone beam computed tomography Magnetic resonance imaging Interactive CT TYPES OF IMAGING MODALITIES

9. Periapical radiography is used to find the presence of pathosis and location of anatomic structures around the implant site,and evaluate implants postoperatively. It is used to determine vertical height of the edentulous region, architecture, and bone quality. Periapical radiography

10. Paralleling technique Bisecting angle technique

11. 45-year-old male patient imaged for the evaluation of the implant. Periapical radiograph of the left mandibular posterior region shows the osseointegrated implant (arrows).

12. The film is replaced by a sensor that collects the data. Data is interpreted by a specialized software and the image is formed on a computer screen. Types of sensors: Charge-coupled device ( CCD ) (commonly used) Complementary metal oxide semiconductor / active pixel sensor ( CMOS / APS ) Charge injection device (CID) . DIGITAL RADIOGRAPHY

13. Digital image system

14. Occlusal radiography High-resolution planar images of the mandible or the maxilla are produced by occlusal radiography. Structures like maxillary sinus, nasal cavity, and nasopalatine canal can be assessed through occlusal radiography. Occlusal imaging does not provide detailed information of the facial–lingual dimension of the alveolar ridge.

15. The central x-ray beam passes perpendicular to the film for mandibular image and oblique (45°) for maxillary image.

16. Cephalometric radiography Lateral cephalometric radiography helps in the analysis of the quality of the bony site (ratio of compact to cancellous bone), especially in the anterior region of the mandible. Oriented planar radiographs of the skull. The skull is oriented to the x-ray device and the image receptor using a cephalometer . It fixes the position of the skull with the projections into the external auditory canal. Patient's midsagital plane oriented parallel to the image receptor.

17. These are narrow beam rotational tomographs , which use two or more centers of rotation with a predefined focal trough, to produce an image of both the upper and lower jaws. Optimal patient positioning is crucial in this procedure because jaw positioning errors in the sagittal plane can occur easily, especially in the edentulous patient. It provides an approximation of bone height, vital structures, and any pathological conditions that may be present. Panoramic radiography

18. 65-year-old female with completely edentulous maxillary and mandibular arches. Panoramic radiograph demonstrates a mandibular subperiosteal implant (arrows).

19. Panoramic radiograph with 5 mm ball bearings on the crest of a divison A mandible

20. TOMOGRAPHY Tomography is a generic term formed from the Greek words tomo (slice) and graph(picture) Adopted in 1962 by the International Commission on Radiological Units and Measurements Describe all forms of body section radiography.

21. CT was invented by Sir Godfrey Hounsfield and was introduced in 1972. This modality gives rise to high-density resolution images, and allows soft tissues to be visualized. CT enables differentiation and quantification of soft and hard tissues. COMPUTED TOMOGRAPHY

22. 39-year-old male with mandibular edentulous posterior region. CT of the edentulous area of the mandibular posterior region for the evaluation of bone for implant placement. a) Various sections of CT (arrow); b) shows the inferior alveolar nerve (arrow); and c) shows the arbitrary implant placement (arrow).

23. The x-ray source is attached rigidly to a fan-beam geometry detector array, which rotates 360 degrees around the patient and collects data. The image detector is gaseous or solid state, producing electronic signals that serve as input data for a dedicated computer. CT images are inherently three-dimensional digital images, typically 512X512 pixels with a thickness described by the slice spacing of the imaging technique.

24. The individual element of the CT image is called a voxel , which has a value, referred to in Hounsfield units , that describes the density of the CT image. The density of structures within the image is absolute and quantitative and can be used to differentiate tissues in the region and characterize bone quality. Density Hounsfield unit D1 1250 D2 850-1250 D3 350-850 D4 150-350 D5 <150

25. MATERIAL HOUNSFIELD UNITS Air -1000 Water Muscle 35-70 Fibrous tissue 60-90 Cartilage 80-130 Trabecular bone 150-900 Cortical bone 900-1800 Dentin 1600-2400 Enamel 2500-3000

26. DENTASCAN Dentascan is a unique new computer software program which provides computed tomography imaging of the mandible and maxilla in three planes of reference- axial, panoramic, and cross-sectional. Dentascan imaging provides programmed reformation, organization, and display of the imaging study.

27. Types of CT Scanners MEDICAL – These CT scanning units are tomographic machines that are classified as 4-, 8-, 12-, 16-, 32-, and 64-slice machines. The number of slices corresponds to the number of times the x-ray beam rotates around the patient’s head CT spiral slices produce “average” reconstructed images based on multiple x-rays transversing the scanning area. With this reconstruction of images, a small gap between each slice is present, which contributes to an inherent error within medical scanners.

28. To overcome some of the disadvantages of conventional medical CT scanners, a new type of CT specific for dental applications has recently been developed. This type of advanced tomography is termed cone beam volumetric tomography ( CBVT ) or cone beam computed tomography ( CBCT ) The x-ray tube on these scanners rotates 360 degrees and will capture images of the maxilla and mandible in 36 seconds , in which only 5.6 seconds is needed for exposure. CONE BEAM VOLUMERIC/COMPUTED TOMOGRAPHY

29. The positioning of patients is similar to medical scans. The images recorded are placed onto a charge coupled device chip with a matrix of 752 x 582 pixels and are then converted into axial, sagittal, and coronal slices, and permit reformatting to view traditional radiographic images as well as three-dimensional soft tissue or osseous images.

30. The primary difference between CBCT and CT is the shape of radiation beams and the mode of motion. In contrast to the fan-beam generated by CT scanners, however, the CBCT scanner generates a cone-shaped x-ray beam , which images a larger area. Thus, at the end of a single complete rotation, 180 to 500 images of the area are generated. The computer uses these images to generate a digital, three-dimensional map of the face.

31. 30-year-old female patient with edentulous mandibular anterior region. CBCT shows implant placement site in the mandibular anterior region. 40-year-old male with mandibular posterior region. CBCT of mandibular posterior region for the evaluation of implant placement (a) shows the implant size (arrow) using the available bone and (b) points out the cross section of the inferior alveolar nerve (arrow).

32. ICT is a technique that was developed to bridge the gap in information transfer between the radiologist and practitioner. Interactive CT ( ICT ) allows the transfer of images to the clinician as a computer file. It helps the clinician measure the length and the width of the alveolus and also bone quality. An important aspect of ICT is that the clinician and radiologist can together perform “electronic surgery” (ES). Interactive computed tomography

33. The dentist’s computer becomes a diagnostic radiologic workstation with tools to- measure the length and the width of the alveolus, measure bone quality , change the window and level of the grayscale of the study to enhance the perception of critical structures. Axial, cross-sectional, and panoramic images and three-dimensional images are displayed and referenced so that the dentist can appreciate the same position or region within the patient’s anatomy in each of the images. Regions of the patient’s anatomy can be selected for display normally, with magnification , or with a number of grayscale depictions.

34. The first step in the ICT process is the impressions for study casts. With the casts a diagnostic wax-up is completed. A radiopaque template is fabricated from the diagnostic wax-up. This diagnostic template will allow the transfer of the ideal positioning of the teeth.

35. For conventional and CT the positioning of the teeth is integrated into a scanning template by way of a radiopaque material. Which is accomplished by way of an acrylic template coated with barium sulfate , gutta percha markers or radiopaque denture teeth. These radiopaque templates may then be modified into use for surgical templates.

36. Computer-generated drilling guides that are fabricated through the process of stereolithography . These successive diameter surgical osteotomy drill guides may be either bone-, teeth-, or mucosa-borne. Surgiguides have metal cylindrical tubes that correspond to the number of desired osteotomy preparations and specific drill diameters. SURGICAL GUIDES

37. Magnetic resonance imaging (MRI) was first discovered by Lauterbur . A CT imaging technique that produces images of thin slices of tissues with excellent spatial resolution. Uses a combination of magnetic fields that generate images of tissues in the body without the use of ionizing radiation. Allows complete flexibility in the positioning & angulation of image sections & can produce multiple slices simultaneously. Magnetic resonance imaging

38. Digital MRI images are characterized by voxels with an in-plane resolution measured in pixels (512 x 512) and millimeters and a section thickness measured in millimeters (2 to 3 mm) for high resolution imaging acquisitions. The images created by MRI are the result of signals created by hydrogen protons in water or fat such that cortical bone appear black (radiolucent) or as having no signal. Cancellous bone will generate a signal & will appear white because it contains fatty marrow. Metal restorations will not produce scattering and thus will appear as black images. MRI is a quantitatively accurate technique with exact tomographic sections & no distortion.

39. RADIOGRAPHIC IMAGING OF VITAL STRUCTURES IN ORAL IMPLANTOLOGY MENTAL FORAMEN AND MANDIBULAR CANAL The position of the mandibular canal and mental foramen - identified to avoid trauma to the inferior alveolar nerve. Because of the curvature of the mandible, great care must be given to the angulation of the x-ray beam for intraoral radiography.

40. Periapical and panoramic images are still used routinely as the sole determinate of osseous measurements with respect to these vital structures. If the image is taken from a mesio -oblique orientation, measurements will be foreshortened and if the orientation is from a distal-oblique , it will be elongated. In edentulous mandibles, the risk of error increases considerably where there is increased resorption of the alveolar crest.

41. Most accurate means of identification is with conventional and computerized tomography. Studies have shown that tilting the patient’s head approximately 5 degrees downward in reference to the Frankfort horizontal plane allows these anatomical structures to be seen in 91% of radiographs.( Dharmar S)

42. Advanced atrophy in the posterior mandible is present, lingual concavities may be present. Within these concavities or submandibular gland fossa, branches of the facial artery may be present. Overestimation of the amount of bone may lead to perforation of the lingual plate when drilling the osteotomy . Lingual bleeding problems - even be life-threatening. Assessment of the posterior mandible - cross-sectional tomography is recommended. Mandibular Lingual Concavities

43. Mandibular Ramus (Donor Site for Autogenous Grafting) The mandibular ramus area has become a very popular donor site for autogenous onlay bone grafting. This area of the mandibular jaw is extremely variable in the amount of bone present. Usually panoramic images are taken and the location of the external oblique and the mandibular canal is noted. For accurate representation - use of computerized tomography.

44. Mandibular Symphysis A common position for implants in mandibular edentulous patients and used as a donor site for autogenous grafting. When two-dimensional images are used, inherent errors may occur. Radiographs including lateral cephalometric and conventional CT, may be used.

45. Maxillary Sinus CT, which is the gold standard for viewing the osseous structures and evaluating pathology in the sinuses. It provides detailed information regarding – Prevalence and position of septa Maxillary sinus anatomy Detection of sinus pathology

46. Immobility and Radiographic evidence of bone adjacent to the implant are the two most accurate diagnostic aids in evaluating success. Follow-up or recall radiographs should be taken after 1 year of functional loading and yearly for the first 3 years. RECALL AND MAINTENANCE IMAGING

47. Digital subtraction radiography, allows two radiographs taken at different times to be superimposed on one another, resulting in an image that exhibits the differences in the bone level. Subtraction radiography requires the use of the same positioning and imaging technique between the two radiographs with respect to the x-ray source, patient and film position, exposure, and processing variables. Subtraction Radiography

48. After the images are subtracted, a subtraction image will be left that depicts the osseous changes between the radiographs. This technique has been shown to be more accurate in accessing bone mineralization and volume changes.

49. Many radiographic projections are available for the evaluation of implant placement, each with advantages and disadvantages The clinician must follow sequential steps in patient evaluation, and radiography is an essential diagnostic tool for implant design and successful treatment of the implant patient. CONCLUSION

50. Contemporary Implant Dentistry. Carl E. Misch – 3rd Edition. Nagarajan A. Diagnostic Imaging for Dental Implant Therapy. J Clin Imaging Sci. 2014; 4( Suppl 2): 4 REFERENCES

51. THANK YOU