Radiographic aids used in Periodontal Diagnosis

Diagnostic imaging is an essential component in dental medicine, which supplements findings from clinical examination, facilitates the planning of non‐ surgical and surgical procedures, and assists in monitoring of treatment outcomes.
The selection of an appropriate imaging modality should be based on the underlying condition of each patient including considerations of a potential benefit to a patient, which should comprise the risks of biological effects due to added radiation due to the radiographs taken.

Radiographs are valuable for the diagnosis of periodontal disease, estimation of severity, determination of prognosis, and evaluation of treatment outcome. However, radiographs are an adjunct to the clinical examination, not a substitute for it. Radiographs demonstrate changes in calcified tissue; they do not reveal current cellular activity but rather reflect the effects of past cellular experience on the bone and roots.

Periodontology and implantology treatment require a long treatment and follow‐up period - during this period, several imaging examinations may be required for diagnosis, treatment planning, postoperative evaluation, and follow‐up assessments. Therefore, dental practitioners should always follow ALARA/ALADA principles to reduce radiation dose exposure for each imaging examination to minimize the accumulated dose to the patient.

1. ADVANCED RADIOGRAPHIC DIAGNOSTIC AIDS IN PERIODONTAL DIAGNOSIS Dr Akriti II MDS 1

2. CONTENT INTRODUCTION HISTORY USE OF RADIOGRAPHS IN PERIODONTICS RADIOGRAPHIC TECHNIQUES INTRAORAL TECHNIQUES PERIAPICAL RADIOGRAPHY BITEWING RADIOGRAPHY OCCLUSAL RADIOGRAPHY DIGITAL RADIOGRAPHY EXTRAORAL TECHNIQUES PANORAMIC RADIOGRAPHY CEPHALOMETRIC RADIOGRAPHY COMPUTED TOMOGRAPHY CONE BEAM COMPUTED TOMOGRAPHY PART 1 2

3. INTRODUCTION Diagnostic imaging is an essential component in dental medicine, which supplements findings from clinical examination, facilitates the planning of non‐ surgical and surgical procedures, and assists in monitoring of treatment outcomes. The selection of an appropriate imaging modality should be based on the underlying condition of each patient including considerations of a potential benefit to a patient, which should comprise the risks of biological effects due to added radiation due to the radiographs taken. 3

4. HISTORY 4

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6. Sir William Morgan (1795) and Michael Faraday (1800) : first to generate X-rays Wilhelm Hittorf (1870) and William Crookes (1879) implemented modifications to vacuum tubes and generated X-rays during their experiments. The latter even noticed the fogging of photographic film that was left in the vicinity of his experimental set-up, but did not make the connection that Röntgen did. Philip Lenard (1890s) studied cathode rays, and was the primary inspiration to Röntgen’s experiment, which was essentially a repetition of Lenard’s work with a different type of tube (i.e. a Crookes-Hittorf tube with a thicker glass wall). The reason why Lenard did not notice the production of X-rays has been attributed to the use of a material that, unlike barium platinocyanide, shows no fluoresce from X-rays. Arthur Goodspeed and William Jennings (1890) accidentally created a radiograph, showing the outline of two coins, by leaving a photographic plate in the vicinity of a Crookes-Hittorf tube . 6 Pauwels R. History of dental radiography: Evolution of 2D and 3D imaging modalities. Med Phys Int. 2020 Mar;8(1):235-77.

7. W.C. Röntgen reported the discovery of X-rays in December 1895 after seven weeks of assiduous work during which he had studied the properties of this new type of radiation able to go through screens of notable thickness. He named them X-rays to underline the fact that their nature was unknown. His wife, Anna Bertrand Röntgen, has gone down in history as the first person that underwent X-ray radiography on December 22, 1895, by placing her left hand on a photographic plate for 15 min. Two weeks after the publication of Röntgen’s discovery, the German dentist Otto Walkhoff acquired a radiograph of his own teeth with the help of Fritz Giesel . An exposure time of a whopping 25 min was used. In 1896 , Walkhoff and Giesel established the first dental X-ray laboratory in the world. Later-on, Walkhoff also produced extra-oral radiographs. 7 Pauwels R. History of dental radiography: Evolution of 2D and 3D imaging modalities. Med Phys Int. 2020 Mar;8(1):235-77.

8. USE OF RADIOGRAPHS IN PERIODONTICS Radiographs are valuable for the diagnosis of periodontal disease, estimation of severity, determination of prognosis, and evaluation of treatment outcome. However, radiographs are an adjunct to the clinical examination, not a substitute for it. Radiographs demonstrate changes in calcified tissue; they do not reveal current cellular activity but rather reflect the effects of past cellular experience on the bone and roots. Corbet EF, Ho DK, Lai SM: Radiographs in periodontal disease diagnosis and management, Aust Dent J 54(Suppl 1):S27–S43, 2009. 8

9. 9 Tugnait and colleagues, 2000 reviewed the usefulness of radiographs in diagnosis and management of periodontal diseases - concluded that various features of periodontal diagnostic interest are apparent on radiographs and visualization of these depends on the radiographic view chosen; a relationship exists between clinical attachment and radiographic bone height; radiographs can be used in all stages of periodontal care Hausmann, 2000 reviewed radiographs and digital imaging in periodontal practice - terminologies ‘‘accuracy’’ and ‘‘reproducibility’’ in imaging; how to produce standardized X-radiographs and manage serial X-radiographs once these have been digitized; correlation between the radiographic bone height and clinical attachment level; subtraction radiography (being able to tell differences in structures recorded between one standardized radiograph and another) Mol, 2004 reviewed imaging methods in periodontology covering why and when to use the following imaging: intra-oral and extra-oral radiography, digital radiography, digital subtraction radiography, computed tomography and cone-beam CT

10. 10 Tugnait and Carmichael, 2005 reviewed the use of radiographs in the diagnosis of periodontal disease - selection of radiographs following clinical examination and taken only on the basis of clinical findings; each exposure should be justified Bragger, 2005 reviewed radiographic parameters, their biological significance and clinical use - conventional vs digital imaging methods; the radiographic parameters obtainable in daily practice; linear measurements from landmarks to alveolar bone crest and tooth and root lengths, angular defects, defect angles, furcation radiolucencies - noting the influence of methodological errors; biological processes which can be derived from radiographic images and dealt in some detail with the clinical use of radiographs; role of radiographs in establishing a periodontal diagnosis, creating a treatment plan, estimating disease risk, and documenting tissue stability, breakdown or remodelling

11. Highfield J. Diagnosis and classification of periodontal disease. Aust Dent J 2009;54(1 Suppl):S11–S26. 11

12. Highfield J. Diagnosis and classification of periodontal disease.Aust Dent J 2009;54(1 Suppl):S11–S26. 12

13. Vijay G, Raghavan V. Radiology in periodontics. Journal of Indian Academy of Oral Medicine and Radiology. 2013 Jan 1;25(1):24-9. 13

14. RADIOGRAPHIC TECHNIQUES 14

15. IONIZING vs NON-IONIZING RADIATION 15 periapical radiographs, bitewings, occlusal views, panoramic images, cephalometric views, CBCT and CT evaluation of the health and pathology of hard tissues including teeth and jaws X‐rays, high energy photons of electromagnetic waves, penetrate the human body and ionize electrons from atoms or molecules present in the scanned region and cause an exposure on the receptor to generate an image Ultrasound imaging and magnetic resonance imaging (MRI) observation of biological/pathological changes of soft tissues in clinical medicine prevent unnecessary radiation exposure to patients - application of ultrasound, radiofrequency pulse White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

16. INTRAORAL TECHNIQUES 16

17. PERIAPICAL RADIOGRAPHY 17 Assess periodontal bone loss Assess implant osseointegration and peri-implant bone loss Evaluate consequences of traumatic injuries to the teeth and alveolar bone Assess extent of dental caries Detect presence and assess extent of periapical inflammation Evaluate unerupted and impacted teeth Diagnostic Objectives White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

18. Two‐dimensional (2D) image with a restricted field of view (FOV) depicting two or three adjacent teeth and surrounding bone small sized film (ranging from 22 × 35mm to 30.5 × 40.5mm) high spatial resolution and low radiation dose - first line diagnostic imaging modality Film is ideally positioned deep into the lingual vestibule or palatal vault, parallel to the long axis of the teeth or close to the lingual surface of the teeth, and stabilized by a receptor holding instrument. The central X‐ray beam is directed through the external localizing ring of the holding instrument. For periapical radiographs, the long-cone paralleling technique most accurately projects the alveolar bone level. The bisection-of-the-angle technique elongates the projected image, making the bone margin appear closer to the crown; the level of the facial bone is distorted more than that of the lingual. 18 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

19. right-angle technique or long-cone technique x-ray receptor is supported parallel to the long axis of the teeth and the central ray of the x-ray beam is directed at right angles to the teeth and receptor minimizes geometric distortion and presents the teeth and supporting bone in their true anatomic relationships image receptor placed towards the middle of the oral cavity, away from the teeth - results in higher image magnification and poor geometric sharpness - compensated by long source-to-object distance 19 PARALLELING TECHNIQUE White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

20. useful when the operator is unable to apply the paralleling technique because of large rigid sensors or the anatomy of the patient based on Cieszynski's rule of isometry - receptor is positioned as close as possible to the lingual surface of the teeth, resting in the palate or in the floor of the mouth - central ray is directed at a right angle to the plane that bisects the angle between the long axis of the tooth and the receptor Limitation: the alveolar ridge often projects coronal to its true position and distorts the apparent height of the alveolar bone around the teeth 20 BISECTING ANGLE TECHNIQUE White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

21. ANGULATION GUIDELINES FOR IOPAR PROJECTIONS 21

22. ADVANTAGES and DISADVANTAGES 22 Amount of bone loss and peri implantitis can be visualized Low radiation dose Minimal magnification High resolution Proper alignment and positioning Inexpensive Unable to produce any cross-sectional information, buccal-lingual dimension of the alveolar ridge, precise position of critical anatomic structures Distortion and magnification Minimal site evaluation Difficulty in film placement Technique sensitive White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

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24. 24 Pepelassi EA, Tsiklakis K, Diamanti‐Kipioti A. Radiographic detection and assessment of the periodontal endosseous defects. Journal of clinical periodontology. 2000 Apr;27(4):224-30. Periapical radiography was more successful than panoramic in detecting osseous defects, and more accurate in assessing the defect dimensions (depth, mesiodistal width)

25. BITEWING RADIOGRAPHY Assess loss of the interdental and furcation bone Detect early interproximal caries before it becomes clinically apparent Detect secondary caries below restorations 25 Diagnostic Objectives White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

26. Also called interproximal radiographs Include the crowns of the maxillary and mandibular teeth and the alveolar crest on the same receptor Long axis of bitewing receptors usually is oriented horizontally but may be oriented vertically - placed parallel to the buccal and lingual surfaces of the teeth being examined Beam is directed through the interproximal spaces and parallel with the occlusal plane - receptor is perpendicular to the x-ray beam The bitewing instruments have a bite plate and an external guide ring to aid positioning the tube head - bite block facilitates positioning of the receptor parallel to the facial surfaces of the teeth being radiographed 26 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

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28. 28 Manja CD, Fransiari ME. A comparative assessment of alveolar bone loss using bitewing, periapical, and panoramic radiography. Bali Medical Journal. 2018 Oct 3;7(3).

29. OCCLUSAL RADIOGRAPHY To locate supernumerary, unerupted, and impacted teeth To evaluate the integrity of the anterior, medial, and lateral outlines of the maxillary sinus To aid in the examination of patients with trismus To localize foreign bodies in the jaws and floor of the mouth To identify and determine the full extent of disease (e.g., cysts, osteomyelitis, malignancies) in the jaws, palate, and floor of the mouth 29 Diagnostic Objectives White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

30. large receptor (7.7 cm × 5.8 cm [3 inches × 2.3 inches]) is inserted between the occlusal surfaces of the teeth - x-ray beam is directed through the jaw to the receptor Disadvantage: Has limited reproducibility (replication of the imaging region) Does not reveal true buccolingual width in mandible Superimposition of images (lack of distinctiveness of the image due to overlapping of the structures) is common Difficulty in positioning 30 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

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32. DIGITAL INTRAORAL RADIOGRAPHY 32 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. Resultant image can be modified in terms of gray scale, brightness, contrast, inversion and color enhancement Types of sensors: Charge-coupled device (CCD) (commonly used) Complementary metal oxide semiconductor / active pixel sensor (CMOS/APS) Charge injection device (CID) White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

33. 33 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222. ADVANTAGES and DISADVANTAGES Less radiation because the sensors are more sensitive (exposure time is 50-90% less) Immediate result Ability to enhance the images 🡪 lead to more effective diagnosis Patient education is better No need of processor, chemicals, special rooms, film, etc. High initial start-up costs Staff and the doctor must be trained on how to take, view, and manipulate Increased thickness of the sensors & position of the connecting cord (Positioning of sensor difficult in some sites such as those adjacent to tori or tapered arch form in region of canines)

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35. 35 Brägger U. Digital imaging in periodontal radiography: A review. Journal of clinical periodontology. 1988 Oct;15(9):551-7.

36. EXTRAORAL TECHNIQUES 36

37. PANORAMIC RADIOGRAPHY Overall evaluation of dentition Examine for intraosseous pathology, such as cysts, tumors, or infections Gross evaluation of temporomandibular joints Evaluation of position of impacted teeth Evaluation of eruption of permanent dentition Dentomaxillofacial trauma Developmental disturbances of maxillofacial skeleton 37 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222. Diagnostic Objectives

38. also called pantomography body section imaging technique that results in a wide, curved image layer depicting the maxillary and mandibular dental arches and their supporting structures As the x-ray tube head moves around one side of the patient, the receptor assembly moves toward the opposite side - image receptor slides past the collimator, sequentially producing a latent image. 38 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

39. ADVANTAGES and DISADVANTAGES Broad coverage of facial bones and teeth Low radiation dose Ease of panoramic radiographic technique Can be used in patients with trismus or in patients who cannot tolerate intraoral radiography Quick and convenient radiographic technique Useful visual aid in patient education and case presentation 39 Lower-resolution images Magnification across image is unequal, making linear measurements unreliable Image is superimposition of real, double, and ghost images and requires careful visualization to decipher anatomic and pathologic details Requires accurate patient positioning to avoid positioning errors and artifacts Difficult to image both jaws when patient has severe maxillomandibular discrepancy White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

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41. Persson RE, Tzannetou S, Feloutzis AG, Brägger U, Persson GR, Lang NP. Comparison between panoramic and intra‐oral radiographs for the assessment of alveolar bone levels in a periodontal maintenance population. Journal of clinical periodontology. 2003 Sep;30(9):833-9. 41 I-O and OPG radiograph readings are in great agreement. Alveolar bone loss appeared to have a symmetrical distribution pattern. Hence for periodontal assessments, OPG radiograph readings may, at least in part, substitute for full-mouth periapical radiographic evaluation.

42. 42 Kweon HH, Lee JH, Youk TM, Lee BA, Kim YT. Panoramic radiography can be an effective diagnostic tool adjunctive to oral examinations in the national health checkup program. Journal of periodontal & implant science. 2018 Oct 26;48(5):317-25. Panoramic radiography can provide information that is difficult to obtain in oral examinations, such as root caries, furcation involvement, and subgingival calculus, which are factors that can directly affect the survival rate of teeth. It therefore seems reasonable and necessary to add panoramic radiography to large-scale health checkup programs such as that provided by the NHIS.

43. CEPHALOMETRIC RADIOGRAPHY Determination of width of bone in the symphysis region and the relationship between the buccal cortex and the roots of the anterior teeth Provide information regarding the relationship of the jaw to the teeth in the opposite arch, the position of the mental foramen , and the relationship of the inferior border of the nasal fossa and maxillary sinuses to the crests of the edentulous ridges in the maxilla 43 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222. Diagnostic Objectives

44. Oriented planar radiographs of the skull Provides information on the inclination of the maxillary and mandibular alveolar processes and on their vertical and facial-lingual dimension in the midsagittal plane 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 midsagittal plane oriented parallel to the image receptor. 44 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

45. ADVANTAGES and DISADVANTAGES 45 Low magnification Skeletal relationship Evaluation of quantity of bone in anterior region Reduced resolution Technique sensitive Image information is limited to ant. region. Overly optimistic bone volume assessments are created due to the presence of genial tubercles. White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

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47. 47 LIMITATIONS OF 2-D RADIOGRAPHS : The condition of gingiva cannot be predicted from the radiographic appearance of alveolar crest Radiographs provide two-dimensional views of three dimensional situations. They often fail to disclose osseous destruction particularly that confined to the buccal or lingual surfaces of teeth Radiographs typically show less severe bone destruction than is actually present Measure of bone level from the CEJ is not valid when there is over eruption or severe attrition with passive eruption. Radiographs do not demonstrate the soft tissue to hard tissue relationship and thus provide no information about the depth of soft tissue pockets. However, if a radiopaque material, such as gutta-percha is inserted into the pocket, the base of the pocket can usually be recorded on the radiograph Widening of PL space on radiograph does not necessarily indicate tooth mobility They do not specifically distinguish between the successfully treated cases and the untreated cases. Vijay G, Raghavan V. Radiology in periodontics. Journal of Indian Academy of Oral Medicine and Radiology. 2013 Jan 1;25(1):24-9.

48. COMPUTED TOMOGRAPHY Soft-tissue evaluation Single-site evaluation Vital structures evaluation 48 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222. Indications

49. Radiographic technique designed to obtain clearer images of structures lying within a plane of interest - invented by Sir Godfrey Hounsfield and was introduced in 1972 Tomographic units produce cross sectional slices of the jaws that can be as thin as 1mm - the series of axial slices captured can be reconstructed into 3D images, which allows for the visualization and assessment of anatomic structures at different planes The x-ray source is attached rigidly to a fan-beam geometry detector array, which rotates 360 degrees around the patient and collects data Tomograms can provide the clinician information: An accurate assessment of alveolar bone height Bone width and inclination Bone quality 49 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

50. The mandible usually requires 30-35 axial slices, whereas the maxilla may require 20-30 Mandibular scanning begins at a plane through the cusps of the teeth and proceeds just beyond the lower border of the mandible. Maxillary scans begin at a plane through the cusps of the teeth and proceed just beyond the most cranial extent of the hard palate. The individual element of the CT image is called a voxel, which has a value, referred to in Hounsfield units🡪Describes the density of the CT image The image detector is gaseous or solid state, producing electronic signals that serve as input data for the imaging computer - can create secondary images from almost any perspective by reprojecting or reformatting the original 3D voxel data CT image generates axial, panoramic, and cross-sectional images that allow rapid correlation of the different views 50 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

51. According to Mallya & Lam (2019), compared with CBCT, computed tomography imaging has relatively superior soft tissue contrast resolution that can show density differences between certain types of soft tissues, which may be helpful for the evaluation of different soft tissue masses in the dental and maxillofacial region. Contraindications for CT include: Claustrophobia Parkinson’s disease Tremors Disabling conditions that might cause a patient to be uncooperative . 51 Mallya S, Lam E. White and Pharoah's Oral radiology E-book: principles and interpretation: second South Asia Edition E-Book. Elsevier India; 2019 May 15.

52. ADVANTAGES and DISADVANTAGES 52 Images are free from the superimposition of images or structures superficial or deep to the plane of interest Negligible magnification High contrast image 3-dimensional bone models High dose of radiation 🡪 Highly radiosensitive organs are near the area of exposure, such as the thyroid gland, parotid gland, bone marrow, and lens of the eye High cost of machines Image artifacts caused by metal Technique errors, and the need for special training in image interpretation Patient movement including swallowing will cause distortion of the image White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

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55. CONE BEAM COMPUTED TOMOGRAPHY Exact measurement of the length and width of the alveolar ridge Pre-surgical evaluation (,medium to large FOV) Localization of an unerupted tooth (small FOV) Assessment of external resorption in relation to unerupted teeth (small FOV) Assessment of cleft palate (medium FOV) 55 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222. Indications

56. White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222. 56

57. Introduced in late 1990s in the field of dentistry CBCT imaging is an effective volumetric diagnostic imaging technology that produces accurate, submillimeter resolution images of diagnostic quality in formats enabling volumetric visualization of the osseous structures of the maxillofacial region at lower doses and costs. CBCT scanner generates a cone-shaped x-ray beam (fan-beam in CT) The x-ray tube on these scanners rotates 360 degrees and captures images of the maxilla and mandible in 36 seconds, in which only 5.6 seconds is needed for exposure - at the end of a single complete rotation, 180 to 500 images of the area are generated. The images recorded are placed onto CCD chip with a matrix of 752 x 582 pixels and are then converted into axial, sagittal, and coronal slices. 57 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

58. 58 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

59. Corbet EF, Ho DK, Lai SM: Radiographs in periodontal disease diagnosis and management, Aust Dent J 54(Suppl 1):S27–S43, 2009. 59

60. The use of CBCT in the field of periodontics: linear measurement of alveolar bone loss detecting the ligament space with a width of 0.19 mm measure the distance from the CEJ to alveolar crest allows periodontal defects to be observed in all three dimensions imaging defect shape, lingual or buccal furcation defects and furcation involvement - most accurate for assessing disto-palatal furcations, followed by buccal and mesio-palatal defects 60 Du Bois AH, Kardachi B, Bartold PM. Is there a role for the use of volumetric cone beam computed tomography in periodontics?. Australian dental journal. 2012 Mar;57:103-8.

61. Radiation dose: 40% less than medical CT It generates a 3D dataset Potential for generating all 2D images Allows vertical scanning with the patient in a seated position Generates high-resolution images Rapid scanning procedure Reduced disturbance from metal artifacts Lower cost, easy accessibility, easy handling 61 ADVANTAGES and DISADVANTAGES Low contrast range. Restricted field of view (FOV). Reduced scanned volume caused by limited detector size Because of the low radiation dose, CBCT can only provide bony detail and is unable to provide images of the soft tissues Increased noise from scatter radiation White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

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63. 63 Walter C, Schmidt JC, Dula K, Sculean A. Cone beam computed tomography (CBCT) for diagnosis and treatment planning in periodontology: A systematic review. Quintessence Int. 2016 Jan 1;47(1):25-37.

64. 64 Bayat S, Talaeipour AR, Sarlati F. Detection of simulated periodontal defects using cone-beam CT and digital intraoral radiography. Dentomaxillofacial Radiology. 2016 Jul;45(6):20160030. CBCT scans were significantly superior to digital radiographs for the detection of Grade I furcation involvements, three-wall defects, fenestrations and dehiscence (p < 0.05). No significant difference was noted between CBCT and digital radiography for the detection of Grades II and III furcation involvements, one-wall, two-wall and trough-like defects (p> 0.05).

65. Grimard BA, Hoidal MJ, Mills MP, Mellonig JT, Nummikoski PV, Mealey BL. Comparison of clinical, periapical radiograph, and cone‐beam volume tomography measurement techniques for assessing bone level changes following regenerative periodontal therapy. Journal of periodontology. 2009 Jan;80(1):48-55. 65 Overall, compared to direct surgical measurements, CBVT was significantly more precise and accurate than IRs.

66. Digital subtraction radiography is an image enhancing technique which removes the structured noise digitally, thereby displaying the areas of change clearly either against a neutral gray background or superimposed on the original radiograph itself. The basic principle is - Two radiographs are made, one before the treatment and one at sometime after treatment, and are compared on pixel by pixel basis. The components of the image that are unchanged are subtracted and the subtle changes which have occurred are made evident. The change will appear as brighter area when the change represents gain and as a darker area when the change represents loss. 66 SUBTRACTION RADIOGRAPHY Mehra , Anshul ; Sholapurkar , Amar A.; Ahsan , Auswaf ; Pai , Keerthilatha M. Digital Subtraction Radiography-A Technique Revisited. Journal of Indian Academy of Oral Medicine and Radiology 19(4):p 517-522, October–December 2007.

67. Ruttimann UE, Webber RL, Grondahl HG. Subtraction Radiography in Dentistry. Proc Annu Symp Comput Appl Med Care. 1982 Nov 2:937–42. PMCID: PMC2580330. 67

68. Gröndahl HG, Gröndahl K, Webber RL. A digital subtraction technique for dental radiography. Oral Surgery, Oral Medicine, Oral Pathology. 1983 Jan 1;55(1):96-102. 68

69. Goel A, Chieng R, Jafar M, et al. Digital radiography. Reference article, Radiopaedia.org (Accessed on 09 Jun 2023) https://doi.org/10.53347/rID-30328 69 DIGITAL RADIOGRAPHY

70. Brägger U, Pasquali L, Rylander H, Carnes D, Kornman KS. Computer‐assisted densitometric image analysis in periodontal radiography: A methodological study. Journal of clinical periodontology . 1988 Jan;15(1):27-37. 70 CADIA

71. CONTENT READING A RADIOGRAPH - IOPAR vs OPG vs CBCT RADIOGRAPHIC FEATURES OF HEALTHY PERIODONTIUM RADIOGRAPHIC FEATURES OF PERIODONTAL DISEASE CONDITIONS DESTRUCTIVE PROCESS AND PROGNOSIS ADVANCED DIAGNOSTIC TRENDS ULTRASOUND MRI RADIOGRAPHS IN IMPLANTOLOGY DIAGNOSTIC IMAGING AND ARTIFICIAL INTELLIGENCE IN PERIODONTOLOGY CONCLUSION PART 2 71

72. READING A RADIOGRAPH 72

73. IOPAR Diagnostic imaging is mainly used to identify the presence of bone destruction and also to assess bone defect morphology. Periapical radiography has the advantage of depicting the full length of the tooth, which is more suitable for the evaluation of the extent of periodontal bone destruction. A full‐ mouth intraoral X‐ray examination is recommended for patients with clinical symptoms and/or signs of general periodontitis or periodontitis‐susceptible patients 73 Lindhe , J. (2008) Text Book of Clinical Periodontology and Implant Dentistry. 5th Edition, Wiley Blackwell, UK, 748-754.

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79. OPG The panoramic image represents the curved jaw that is unfolded onto a flat plane. In the posterior regions, the panoramic image depicts a sagittal view of jaws In the anterior sextant, it depicts anteroposterior view Excessively wide or narrow anterior teeth suggest malposition of the patient in the focal trough. Similarly, teeth that are wider on one side than the other suggest that the patient's sagittal plane was rotated. 79 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

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82. CBCT CBCT displays two dimensional and three dimensional images that are necessary for the assessment, diagnosis and treatment planning of - furcation involvement periodontal ligament space soft tissue alveolar bone defects regenerative periodontal therapy and bone grafts maxillary sinus 82 White, S.C. and Pharoah, M.J. (2009) Oral Radiology Principles and Interpretation. 6th Edition, Mosby, St. Louis, 175-190, 221-222.

83. 83 European Commission, Directorate-General for Energy, Cone beam CT for dental and maxillofacial radiology – Evidence-based guidelines, Publications Office, 2012.

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85. 85 FURCATION INVOLVEMENT Furcation involvement can not be observed in the panoramic like section (A); whereas it can be evaluated in the axial (B); and cross sectional (C) cone beam computed tomography image (arrows).

86. 86 Cone-beam computed tomography images depicting the complete periodontal furcation involvement of a second molar, showing (a) furcation involvement delineated by the circle, (b, c) the extent of the lesion (arrows) from the facial-lingual and axial views.

87. 87 The software i-Dixel-3DX, with a linear measurement tool and a digital magnification lens, was used. It facilitates a continuous motion with the cursor in the 3D area visualized in the three planes on the computer screen. FI was calculated in the horizontal plane by measuring the distance between the outer root surface and the inter-radicular bone to the nearest mm.

88. 88 A: fusion of the whole or part of two adjacent roots indicated by the lack of a separating PDL A1: fusion of m-b and d-b root A2: fusion of m-b and palatal root A3: fusion of d-b and palatal root B: root proximity indicated by two separating PDL B1: root proximity at buccal roots B2: root proximity at m-b and palatal root B3: root proximity at d-b and palatal root C: periapical lesion C1: periapical lesion at the m-b root C2: periapical lesion at the d-b root C3: periapical lesion at the palatal root D: combined periodontal-endodontic lesion D1: periodontal-endodontic lesion at the m-b root D2: periodontal-endodontic lesion at the d-b root D3: periodontal-endodontic lesion at the palatal root E: other findings, such as root perforation, fenestration defects, missing buccal/palatal bone plate or overfill of the root canal

89. 89 PERIODONTAL LIGAMENT SPACE The expansion of the periodontal ligament space is seen in the right maxillary first premolar tooth (black arrow).

90. 90

91. 91 SOFT TISSUE CBCT is a more appropriate tool for evaluating mineralized tissues than soft tissues. However, a practical method named soft tissue CBCT (ST-CBCT), was reported, and it was utilized to determine the dimensions and relationships of the structures of the dentogingival unit. The tongues were retracted toward the floor of patients’ mouths and a plastic lip retractor was used to retract the soft tissues away from the teeth and gingiva during CBCT scans and the images that were obtained provided clear information for the analysis of various dentogingival unit measurements.

92. A, Clinical intraoral picture of a patient with a medium periodontal biotype. B, Image of the cone-beam computed tomography (CBCT) scan taken without the lip retractor showing that the lip (L) collapses onto the facial aspect of the tooth and that the tongue (T) completely occupies the oral cavity. C, Image of the soft tissue CBCT scan showing a dark space (asterisks) on the facial and palatal/lingual aspects allowing the clear visualization of the facial (arrow) and palatal (arrowhead) gingiva. 92

93. A, Measurement of the thickness of the facial gingiva performed on the image of the patient with a thick periodontal biotype (soft tissue cone-beam computed tomography scan). B, Measurement of the distance of the gingival margin to the facial bone crest. C, Measurement of the distance of the gingival margin to the cementoenamel junction. Dotted lines represent the long axis of the tooth. 93

94. ALVEOLAR BONE DEFECTS Cone-beam computed tomography showing a three-dimensional depiction of periodontal bone loss around a maxillary second premolar tooth. The arrows indicate the extent of bone loss on the facial, palatal, mesial and distal aspects of the tooth. 94

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96. 96

97. REGENERATIVE PERIODONTAL THERAPY AND BONE GRAFTS The block graft and mini screw providing graft stabilization are placed in the maxillary anterior region (A and B), the amount of bone augmentation can be evaluated in the cross-sectional images (C and D). 97

98. MAXILLARY SINUS Yeung AW, Hung KF, Li DT, Leung YY. The use of CBCT in evaluating the health and pathology of the maxillary sinus. Diagnostics. 2022 Nov 16;12(11):2819. 98 With the versatility of a CBCT machine, multiple parameters ranging from the spatial resolution, peak voltage to the number of projections can be adjusted to optimize the radiation dose emitted, such that the principle of “as low as reasonably achievable” (ALARA) has gone through a long history of evolution, with some expert opinions that advocated to rename it to “as low as diagnostically acceptable” (ALADA) and, more recently, “as low as diagnostically acceptable being indication-oriented and patient-specific” (ALADAIP). For sinus anatomy, scans are checked for posterior superior alveolar artery, sinus pneumatization, sinus hypoplasia, sinus septa, and primary and accessory sinus ostia. For pathology, membrane thickening associated with periapical lesions/periodontal lesions, mucous retention cyst, and antrolith is checked.

99. 99

100. 100

101. Hung, K.F.; Hui, L.L.; Leung, Y.Y. Patient-specific estimation of the bone graft volume needed for maxillary sinus floor elevation: A radiographic study using cone-beam computed tomography. Clin. Oral Investig. 2022, 26, 3875–3884. 101

102. Kirkham‐Ali K, La M, Sher J, Sholapurkar A. Comparison of cone‐beam computed tomography and panoramic imaging in assessing the relationship between posterior maxillary tooth roots and the maxillary sinus: A systematic review. Journal of investigative and clinical dentistry. 2019 Aug;10(3):e12402. 102

103. 103 RADIOGRAPHIC FEATURES OF HEALTHY PERIODONTIUM

104. In health, the lamina dura around the roots of the teeth appears as a dense radiopaque line. The normal periodontal ligament space appears as a continuous thin radiolucent line on the mesial and distal aspects of the teeth between the roots and the lamina dura and is of uniform thickness. The normal healthy alveolar crest is located approximately 1.5 to 2 mm apical to the cementoenamel junctions (CEJ) of adjacent teeth. In the anterior region, the alveolar crest appears sharp and pointed. In the lower incisor area, the sharp crests are normally covered by dense bone which is actually a continuation of the lamina dura . In the posterior regions, the alveolar crest appears flat and smooth. They are sometimes covered with a thin layer of dense cortical bone, which may be seen as a thin white line. 104 Vijay G, Raghavan V. Radiology in Periodontics. J Indian Acad Oral Med Radiol 2013;25(1): 24-29.

105. 105

106. 106 RADIOGRAPHIC FEATURES OF PERIODONTAL DISEASE CONDITIONS

107. PERIODONTITIS 107 Fuzziness and disruption of lamina dura Widening of the periodontal space results Reduced height of the interdental bone Height of the interdental septum is progressively reduced by the extension of inflammation and the resorption of bone Radiopaque horizontal line across the roots of a tooth - demarcates the portion of the root where the labial or lingual bony plate has been partially or completely destroyed from the remaining bone-supported portion Carranza FA, Takei HH, Newman MG. Clinical Periodontology.13th Ed. California:Elsevier Saunders; 2006. p9-47, 132-157, 728-745.

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109. 109

110. 110

111. FURCATION INVOLVEMENT 111 To assist in the radiographic detection of furcation involvement, the following diagnostic criteria are suggested: The slightest radiographic change in the furcation area should be investigated clinically, especially if there is bone loss on adjacent roots. Diminished radiodensity in the furcation area in which outlines of bony trabeculae are visible suggests furcation involvement. Whenever there is marked bone loss in relation to a single molar root, it may be assumed that furcation is also involved. Radiographs should be taken at different angles to reduce the risk of missing furcation involvement. Carranza FA, Takei HH, Newman MG. Clinical Periodontology.13th Ed. California:Elsevier Saunders; 2006. p9-47, 132-157, 728-745.

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113. 113

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115. 115

116. PERIODONTAL ABSCESS 116 The typical radiographic appearance of a periodontal abscess is a discrete area of radiolucency along the lateral aspect of the root. However, the radiographic picture is often not characteristic. This can be due to: The stage of the lesion. The extent of bone destruction and the morphologic changes of the bone. The location of the abscess. Carranza FA, Takei HH, Newman MG. Clinical Periodontology.13th Ed. California:Elsevier Saunders; 2006. p9-47, 132-157, 728-745.

117. 117

118. 118

119. AGGRESSIVE PERIODONTITIS 119 Localized aggressive (formerly “localized juvenile”) periodontitis is characterized by the following: Initially, there is bone loss in the maxillary and mandibular incisor or first molar areas, usually bilaterally, resulting in a vertical, arclike destructive pattern. As the disease progresses, loss of alveolar bone may become generalized but remains less pronounced in the premolar areas. Carranza FA, Takei HH, Newman MG. Clinical Periodontology.13th Ed. California:Elsevier Saunders; 2006. p9-47, 132-157, 728-745.

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121. OCCLUSAL TRAUMA 121 Traumatic occlusal force is defined as any occlusal force resulting in injury of the teeth and/or the periodontal attachment apparatus. Occlusal trauma is a lesion in the periodontal ligament, cementum and adjacent bone caused by traumatic occlusal forces. It is a histologic term; however, a clinical diagnosis may be made in the presence of one or more of the following: progressive tooth mobility adaptive tooth mobility (fremitus) radiographically widened periodontal ligament space tooth migration discomfort/pain on chewing root resorption Carranza FA, Takei HH, Newman MG. Clinical Periodontology.13th Ed. California:Elsevier Saunders; 2006. p9-47, 132-157, 728-745. Jepsen S, Caton JG, et al. Periodontal manifestations of systemic diseases and developmental and acquired conditions: Consensus report of workgroup 3 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 2018;89(Suppl 1):S237–S248.

122. Occlusal trauma can produce radiographically detectable changes in the thickness of the lamina dura, morphology of the alveolar crest, width of the PDL space, and density of the surrounding cancellous bone. Traumatic lesions manifest more clearly in faciolingual aspects than mesiodistally. Slight variations in the proximal surfaces may indicate greater changes in the facial and lingual aspects. PRIMARY OCCLUSAL TRAUMA has been defined as injury resulting in tissue changes from traumatic occlusal forces applied to a tooth or teeth with normal periodontal support. This manifests itself clinically with adaptive mobility and is not progressive. SECONDARY OCCLUSAL TRAUMA has been defined as injury resulting in tissue changes from normal or traumatic occlusal forces applied to a tooth or teeth with reduced support. 122 Carranza FA, Takei HH, Newman MG. Clinical Periodontology.13th Ed. California:Elsevier Saunders; 2006. p9-47, 132-157, 728-745. Jepsen S, Caton JG, et al. Periodontal manifestations of systemic diseases and developmental and acquired conditions: Consensus report of workgroup 3 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 2018;89(Suppl 1):S237–S248.

123. The injury phase of trauma from occlusion produces a loss of the lamina dura that may be noted in apices, furcations, and marginal areas. The repair phase of trauma from occlusion is manifested by a widening of the PDL space, which may be generalized or localized. More advanced traumatic lesions may result in deep angular bone loss, which, when combined with marginal inflammation, may lead to intrabony pocket formation. In terminal stages , these lesions extend around the root apex, producing a wide, radiolucent periapical image (cavernous lesions). 123 Carranza FA, Takei HH, Newman MG. Clinical Periodontology.13th Ed. California:Elsevier Saunders; 2006. p9-47, 132-157, 728-745.

124. PERIO-ENDO LESION 124 Endodontic-periodontal lesions, defined by a pathological communication between the pulpal and periodontal tissues at a given tooth, occur in either an acute or a chronic form, and are classified according to signs and symptoms that have direct impact on their prognosis and treatment. Carranza FA, Takei HH, Newman MG. Clinical Periodontology.13th Ed. California:Elsevier Saunders; 2006. p9-47, 132-157, 728-745.

125. 125 Papapanou PN, Sanz M, et al. Periodontitis: Consensus report of Workgroup 2 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 2018;89(Suppl 1):S173–S182.

126. 126

127. 127 DESTRUCTIVE PROCESS AND PROGNOSIS

128. The destructive process of periodontal disease can be evaluated by comparing standardized radiographs taken over regular intervals. When the interdental septal bone crest is rough and irregular and the alveolar bone below the crest is devoid of any suggestion of bone opacity, it is most likely that the resorptive process is active. Nutrient canals indicate active and even rapid bone resorption. If a smooth surface of the alveolar bone with condensation of remaining alveolar bone is seen in the presence of bone loss, a static destructive process or slowly destructive process is indicated. Prognosis based on radiographic information is considered FAIR if the destructive process is not generalized, only a limited amount of bone has been lost, corrective etiologic factors can be identified, the patient’s general health is good and more importantly the patient is motivated to save the remaining teeth and is capable of performing all routine and specialized home-care procedures. 128 Vijay G, Raghavan V. Radiology in Periodontics. J Indian Acad Oral Med Radiol 2013;25(1): 24-29.

129. ADVANCED DIAGNOSTIC TRENDS 129

130. ULTRASOUND 130 non‐ionizing diagnostic modality that is based on the application of ultrasound Transducer emits sound waves of vibratory frequencies in the range of 1–20MHz that pass through or interact with tissues of different acoustic impedance. Subsequently, the reflected sound waves are detected by the transducer, and eventually display a real‐time cross‐sectional 2D image. With the introduction of smaller intraoral transducers, ultrasound imaging may be a promising imaging modality to visualize the gingiva and the surface contour of the alveolar bone. (Caglayan & Bayrakdar 2018). Lindhe, J. (2008) Text Book of Clinical Periodontology and Implant Dentistry. 5th Edition, Wiley Blackwell, UK, 748-754.

131. 131

132. potential for real‐time diagnostic workup and follow‐up evaluations in patients with periodontal diseases can display the gingival thickness, gingival sulcus depth, and several relevant landmarks including the levels of alveolar bone crest, CEJ, and free gingival margin useful to evaluate the stability of periodontal soft and bone tissues during maintenance phase not affected by metal artifacts - helpful for the evaluation of peri‐implant bone resorption However, ultrasound imaging also has certain limitations: only exhibit the morphology of the gingiva and surface contour of the supporting bone and tooth portion not covered by bone - ultrasonic waves cannot traverse bone interpretation of ultrasound images is subjective - dental practitioners may find interpretation difficult 132 Lindhe, J. (2008) Text Book of Clinical Periodontology and Implant Dentistry. 5th Edition, Wiley Blackwell, UK, 748-754.

133. 133 Bains VK, Mohan R, Gundappa M, Bains R. Properties, effects and clinical applications of ultrasound in periodontics: an overview. Periodontal Practice Today. 2008 Dec 1;5(4).

134. Le LH, Nguyen KC, Kaipatur NR, Major PW. Ultrasound for Periodontal Imaging. Dental Ultrasound in Periodontology and Implantology: Examination, Diagnosis and Treatment Outcome Evaluation. 2021:115-29. 134

135. MAGNETIC RESONANCE IMAGING 135 revolutionary imaging technique that has been used in medicine since the 1980s This technique directs a radiofrequency pulse into the patient, who is placed in static magnetic fields generated by the MRI unit. This results in the hydrogen nuclei of the atoms in the body of the patient to absorb resonance energy. As the radiofrequency pulse is turned off, the energy stored in the hydrogen nuclei is released. The scanner of the MRI unit detects the released energy and converts the energy to an electrical signal that is used for image reconstruction. Lindhe, J. (2008) Text Book of Clinical Periodontology and Implant Dentistry. 5th Edition, Wiley Blackwell, UK, 748-754.

136. MRI can provide 3D observations of the periodontal soft tissue - signal intensity changes in the investigated soft tissue using MRI reflect an increased water content, which can help to distinguish inflamed from healthy tissue, and assists in assessing the extent of inflammation. However, there are some limitations when considering MRI for periodontal evaluation : patients with cardiac pacemakers, insulin pumps, and claustrophobia are not suitable candidates for MRI scans several metallic materials used for dental restorations or orthodontic treatment may cause metal artifacts that affect the visibility and detectability of periodontal lesions MRI units are relatively expensive and not as easily accessible to dental practitioners operation of an MRI unit is much more sophisticated so that the scanning should be performed by qualified operators only 136 Lindhe, J. (2008) Text Book of Clinical Periodontology and Implant Dentistry. 5th Edition, Wiley Blackwell, UK, 748-754.

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139. RADIOGRAPHS IN IMPLANTOLOGY 139

140. IOPAR IN IMPLANTOLOGY 140 Periapical radiography can provide an initial assessment regarding the healing of extraction sockets, the presence of retained roots, remaining pathologies, and also the presence of periapical lesions of adjacent teeth. Based on its high spatial resolution, periapical radiography is an excellent tool for the assessment of bone structure, clearly displaying trabecular bone at the edentulous sites. However, the distortion and magnification of a periapical image limits accurate linear distance measurements between the adjacent teeth and distances between the alveolar crest and boundaries of critical anatomic structures, such as the floor of the nasal cavity and maxillary sinus, lingual undercuts of the mandible, or the upper limit of the inferior mandibular canal. Lindhe, J. (2008) Text Book of Clinical Periodontology and Implant Dentistry. 5th Edition, Wiley Blackwell, UK, 748-754.

141. OPG IN IMPLANTOLOGY 141 For patients with multiple missing teeth or a completely edentulous arch, panoramic images are considered as the first‐line imaging modality to provide an estimate of the condition of the remaining teeth and/or bone volume. Moreover, the broad FOV depicted by panoramic images is able to visualize the entire floor of the nasal cavity and maxillary sinus, inferior mandibular canal, and mental foramen, which is helpful for the assessment of the vertical bone dimensions at all edentulous sites. However, , the presence of superimposition artifacts of the spinal cord in panoramic images can affect the assessment of the anterior edentulous site in the maxilla and mandible. Lindhe, J. (2008) Text Book of Clinical Periodontology and Implant Dentistry. 5th Edition, Wiley Blackwell, UK, 748-754.

142. 142

143. CBCT IN IMPLANTOLOGY 143 CBCT evaluation can be used for determining the width, height and distance to the anatomical structures of alveolar process in pre-surgical dental implant planning. Jin et al. studied bone thickness evaluation on the buccal and palatal aspects of the maxillary canine and premolars using CBCT and it was concluded that CBCT images might be advantageous in preoperative planning of dental implants. Immediate implant placement enables one-stage surgery and eliminates bone recovery time. In this technique, dimensions of alveolar process which is selected for dental implant placement and relationships with adjacent anatomical structures of this region should be carefully assessed. Lindhe, J. (2008) Text Book of Clinical Periodontology and Implant Dentistry. 5th Edition, Wiley Blackwell, UK, 748-754. Jin SH, Park JB, Kim N, Park S, Kim KJ, Kim Y, Kook YA, Ko Y. The thickness of alveolar bone at the maxillary canine and premolar teeth in normal occlusion. Journal of periodontal & implant science. 2012 Oct 1;42(5):173-8.

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145. POST-IMPLANT PLACEMENT IMAGING 145 Often, postoperative diagnostic images are taken immediately after surgery to serve as a baseline record of the placed implants. There is no evidence available showing any benefit to the patient to justify routine 2D/3D imaging after intervention, when there is no sign of any potential complication Due to the high spatial resolution, periapical radiography is recommended as the optimal imaging modality used to record the level of the alveolar crest around the placed implants and the interface between the implant and bone tissue. If there are more than five intraoral radiographs one should consider choosing a panoramic radiograph for radiation protection purposes. Lindhe, J. (2008) Text Book of Clinical Periodontology and Implant Dentistry. 5th Edition, Wiley Blackwell, UK, 748-754.

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147. 147 DIAGNOSTIC IMAGING AND AI

148. Digitally coded images generated in medicine that contain diagnostically important patient information are easily converted into computer language, and are thus considered as ideal to bridge the gap between medicine and artificial intelligence. In periodontology, changes in bone density and continuity of the surface contour of the supporting bone could both contribute to the development of AI models for evaluation of periodontal bone defects. Lin et al. 2015, 2017 - proposed test models to automatically or semi-automatically identify and or measure the degree of periodontal bone destruction. Lee et al. 2018 - AI model has been reported to be able to predict the outcome of periodontal treatment (i.e. classifying periodontally compromised teeth into hopeful or hopeless teeth). Future trends for AI models built for periodontal diagnosis and treatment planning should exploit 3D images from CBCT, MDCT, and MRI to realize and implement automated classification of periodontal bone defects, calculation of the volume of bone loss, or propose treatment recommendations. 148 Lindhe, J. (2008) Text Book of Clinical Periodontology and Implant Dentistry. 5th Edition, Wiley Blackwell, UK, 748-754.

149. 149 CONCLUSION Periodontology and implantology treatment require a long treatment and follow‐up period - during this period, several imaging examinations may be required for diagnosis, treatment planning, postoperative evaluation, and follow‐up assessments. Therefore, dental practitioners should always follow ALARA/ALADA principles to reduce radiation dose exposure for each imaging examination to minimize the accumulated dose to the patient. Although MDCT and CBCT allow for the visualization and assessment of anatomic structures or pathological changes in 3D with high diagnostic accuracy and precision, 2D imaging examinations are still considered as the baseline and standard of care. Thus, 3D imaging modalities should only be chosen if conventional imaging techniques do not provide sufficient information for diagnosis and treatment planning purposes in individual cases. The application of non‐ ionizing imaging modalities, including ultrasound and MRI, could eventually eliminate radiation dose exposures to the patient for periodontal and implant‐ related purposes. However, for the time being, such techniques are still limited mostly due to cost, availability, and lack of evidence.

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155. THANKYOU! 155