Dental Caries diagnosis /certified fixed orthodontic courses by Indian dental academy


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Dental Caries diagnosis /certified fixed orthodontic courses by Indian dental academy

  1. 1. CARIESDIAGNOSIS INDIAN DENTAL ACADEMYLeader in Continuing Dental Education
  3. 3. INTRODUCTION Thirty two white horses on a red hill,Champing, stamping, they never stand still! - What am I?
  4. 4. What is diagnosis? Diagnosis is an art and science that results from thesynthesis of scientific knowledge, clinical experience,intuition & common sense Caries diagnosis implies deciding whether a lesion isactive, progressing rapidly or slowly or whether isalready arrested Signs: Clinical examination Supplemental test Symptoms: Anamnestic information ↓ Diagnosis ↓ Treatment planning
  5. 5. ASSESSMENT TOOLSStepwise progression toward diagnosis & treatment planning depends on thorough assessment of the following Patient History Clinical examination Nutritional analysis Salivary analysis Radiographic assessment
  6. 6. HIGH RISK LOW RISK Social HistorySocially deprived Middle classHigh caries in siblings Low caries in siblingLow knowledge of caries High dental aspirations Medical HistoryMedically compromised No such problemXerostomiaLong-term cariogenicmedicine Dietary habitsSugar intake: frequent Infrequent
  7. 7. HIGH RISK LOW RISK Use of fluorideNon-fluoridated area Fluoridated areaNo fluoride supplements Fluoride supplements used Plaque controlPoor oral hygiene Good oral hygienemaintenance maintenance SalivaLow flow rate& buffering Normal flow rate& bufferingcapacity capacity↑ S.mutans & lactobacillus ↓ S.mutans & lactobacilluscounts counts
  8. 8. HIGH RISK LOW RISK Clinical evidenceNew lesions No new lesionsPremature extractions No extraction for cariesAnterior caries restorations Sound anterior teethMultiple/repeated No/few restorationsrestorationsNo fissure sealants Fissure sealedMulti-band orthodontics No appliances
  10. 10. VISUAL-TACTILE METHODSVisual methods: Detection of white spot, discoloration / frank cavitations Without aids, unreliable Magnification loupes- Head worn prism loupes (X 4.5) or surgical microscopes(X 16) may be used comfort, relatively inexpensive, available in various magnification Use of temporary elective tooth separation www.indiandentalacademy .com
  11. 11. G.J. Mount classification Classified caries according to the site and size of thelesion and it is represented in the form of two digits.Site of caries SITE 1 ----- PIT AND FISSURES SITE 2 ----- APPROXIMAL SURFACE SITE 3 ----- CERVICAL AREASSize of cariesSIZE 0 ----- Small and early enough to be remineralized or the lesion has been remineralized and there is just residual stain. ‘Zero’ means no restoration needed. www.indiandentalacademy .com
  12. 12. SIZE 1 ---- Minimal dentinal spread that can be remineralized.SIZE 2 ----Moderate involvement of dentine.SIZE 3 ----Enlarged, with weakened cusps or incisal edges that needs protection. www.indiandentalacademy .com
  13. 13. Tactile methods: Explorers are widely used for the detection of carious tooth structure - Right angled probe- no.6 - Back action probe- no.17 - Shepherds crook- no. 23 - Cowhorn with curved ends- no.2 Dental flossHistory of use of explorers1942- G.V Black: passing the explorer into pits, noting whether or not there is any softening & whether the instrument catches or enters any point www.indiandentalacademy .com
  14. 14. 1956- Simon: recognize marginal changes around a previously placed restoration, accomplished with a mirror & explorer1982- Gilmore: susceptible site can be entered by use of a small sharp explorer1985- Marzouk: Sharp explorer- pressing the tip into pits & fissures will cause it to penetrate the enamel &/ or dentinal caries cone, making a definitive diagnosis1985- Sturdevant: defects are best detected when an explorer provides a tug back / resistance on removal www.indiandentalacademy .com
  15. 15. Use of explorer is not advocated because; Sharp tips physically damage small lesions with intact surfaces Probing can cause fracture & cavitation of incipient lesion. It may spread the organism in the mouth Mechanical binding may be due to non- carious reasons Shape of fissure Sharpness of explorer Force of application Path of explorer placement www.indiandentalacademy .com
  16. 16. Use of explorer• Explorer is useful to remove plaque and debris and check the surface characteristics of suspected carious lesions.• gentle pressure just required to blanch a fingernail without causing any pain or damage• All surfaces of a tooth are cleaned of debris and plaque, using an air syringe and examined visually. Suspicious areas are explored to check for the surface texture. www.indiandentalacademy .com
  17. 17. SMOOTH SURFACE CARIESNon- cavitated: No signs of cavitation after visual or tactile examination. Location: where dental plaque accumulates (gingival margin). Surface characteristics: Matted (not glossy) when a tooth is dried. www.indiandentalacademy .com
  18. 18.  Areas of demineralization not in close proximity to the gingival margin not covered by plaque smooth and glossy are non-cavitatednot active non-cavitated carious lesions. Visual enamel opacity under sound marginal ridge indicate undermined enamel due to dental cariesnon-cavitated carious lesion in dentin www.indiandentalacademy .com
  19. 19. Non-cavitated carious lesionENAMEL DENTIN www.indiandentalacademy .com
  20. 20. Cavitated Lesions: Where there is visual breakdown of a tooth surface, it is classified as cavitated carious lesion. An active cavity on a smooth surface has soft walls or floors shown below: www.indiandentalacademy .com
  21. 21. Questionable Area: All stained smooth coronal tooth surfaces that do not have the characteristics of non-cavitated or cavitated lesions are classified as questionable shown below www.indiandentalacademy .com
  22. 22. Non-Carious Enamel Opacities Opacity not fluorosis Moderate FluorosisMild Fluorosis Severe Fluorosis www.indiandentalacademy .com
  23. 23. Caries in Pit or Fissure Surfaces All discolored areas should be explored using gentle pressure. There is no need to penetrate a suspected lesion with an explorer. If a discolored and non-cavitated area is soft when explored, it is recorded as non-cavitated carious pit or fissure. A cavity is detected when there is an actual hole in the tooth in which an explorer could easily enter the space. An active cavity has soft walls or floors (detected using gentle exploring). www.indiandentalacademy .com
  24. 24.  If there is visual enamel opacity under an ostensibly sound or stained pit or fissure, then the enamel is undermined because of dental caries and the tooth surface is classified with a non-cavitated carious lesion in dentin. www.indiandentalacademy .com
  25. 25. Pit and Fissure Caries Non-cavitated carious lesionEnamel EnamelEnamel www.indiandentalacademy Dentin .com
  26. 26. Cavitated Carious lesion If a discolored area is hard when gently explored then it should be marked as questionable. www.indiandentalacademy .com
  27. 27. Root Caries• Root surface caries comprises of a continuum of changes ranging from minute discolored areas to cavitation that may extend into the pulpFor diagnostic purpose; they may be: Active root surface lesion: • well-defined area showing yellowish or light brown discoloration • covered by visible plaque • presence of softening/ leathery consistency on probing with moderate pressure www.indiandentalacademy .com
  28. 28.  Inactive root surface lesion (arrested): • well-defined dark brown/ black discoloration • smooth and shiny • hard on probing with moderate pressure Active lesion Questionable www.indiandentalacademy .com
  29. 29. Arrested Caries Arrested (remineralized) lesions can be observed clinically as intact, but discolored, usually brown or black spots. The change in color is presumably due to trapped organic debris and metallic ions within the enamel. These discolored, remineralized lesions are intact and are highly resistant to subsequent caries . The arrested caries need not be removed. www.indiandentalacademy .com
  30. 30. Recurrent caries It is diagnosed whenever there is softness due to caries at a defective margin, and when the tip of a periodontal probe (WHO probe) can enter the defect without any resistance. A restoration with a discolored margin or a small marginal ditch (<0.5 mm or the head of the WHO or PSR probe) is recorded as an early recurrent carious area. A larger defect should be classified as advanced recurrent carious area www.indiandentalacademy .com
  31. 31.  There are two valid indicators of recurrent (secondary) caries: • softness at the margin of a filling that is detected using an explorer or • presence of a large defect (a minimum diameter of 0.4 mm) at a margin of a filling with softness in the area. Large defects are associated with a high level of colonization with cariogenic bacteria. Marginal discoloration by itself is not a valid sign for dental caries. www.indiandentalacademy .com
  32. 32. Advanced Recurrent Carious lesions www.indiandentalacademy .com
  33. 33. Nursing bottle caries Vs Rampant cariesSpecific form of rampant caries Acute, widespread caries with early pulpal involvement of teeth that are usually immune to decayPrimary dentition affected Both dentitions affectedC/F: specific pattern- maxillary Rapid appearance of new lesionsincisor →molars Mandibular incisors alsoMandibular incisors not affected affected www.indiandentalacademy .com
  34. 34. RADIOGRAPHY Carious lesions are detectable radiographically when there has been enough demineralization to allow it to be differentiate from normal They are valuable in detecting proximal caries which may go undetected during clinical examination. On average they have around 50% to 70% sensitivity in detecting carious lesions. 40% demineralization is required for definitive decision on caries
  35. 35.  Radiographic examinations include; Bitewing radiographs IOPA radiographs using paralleling technique Dental panoramic tomograph The two important decisions related to radiographic examination are (1) when to take a radiograph and (2) how to evaluate a radiograph for presence of signs of dental caries.
  36. 36. PIT & FISSURE CARIESIncipient occlusal lesions: Not very effective. Caries starts on the walls of the pits & fissures and tends to spread perpendicular to the DEJ Only detectable change is a fine gray shadow at the DEJ. A similar, but a narrower shadow is seen below the occlusal enamel – Mach Band
  37. 37. Moderate occlusal lesions: First to induce specific changes helping in a definitive diagnosis Broad based, thin radiolucent zone in dentin with minimal or no changes in enamel Presence of a band of increased opacity between the lesion and the pulp chamber due to calcification within primary dentin This feature is not seen in buccal caries
  38. 38. Severe occlusal lesions: Readily observed both clinically and radiographically Appear as large cavities in the crowns of the teeth However pulp exposure cannot be determined
  39. 39. PROXIMAL CARIES Density along the proximal surface is high which does not permit the detection of loss of small amounts of mineral contentIncipient lesions: Commonly seen in the caries- susceptible zone Presents as a notch on the outer surface not involving more than half of enamel Diagnosis can be missed, best viewed under a magnifying glass.
  40. 40. Moderate proximal lesions: Involve more than outer half of enamel but do not extend into DEJ May have one of type of appearance: 67% - triangle with broad base towards outer surface 16% - a diffuse radiolucent image 17% - combination of both
  41. 41. Advanced proximal lesions: Radiolucent triangular cone invading into the dentin In addition, it spreads along the DEJ and subsequently into dentin This forms a 2nd cone with base at DEJ Does not involve more than half of dentin In some cases, lesions penetrated into dentin may appear not to have penetrated enamel
  42. 42. Severe proximal lesions: Penetrating more than half of dentin Narrow path through enamel, an expanded radiolucency at DEJ, with a progress towards pulp Lesions may or may not appear to involve pulp Undermined enamel fractures under masticatory load leaving a large cavity
  43. 43. Facial & Lingual Caries They start as round lesions and enlarge to become elliptical or semilunar Presence of well defined non- carious enamel around radiolucency When superimposed on DEJ, they may mimic occlusal caries Clinical examination helps in definitive diagnosis
  44. 44. ROOT SURFACE CARIES Also called cemental caries with an incidence of 40%- 70% of the aged population Buccal, lingual, proximal Usually it is a lesion of dentin associated with recession Ill-defined, saucer-like radiolucency
  45. 45. RECURRENT CARIES Occurs immediately next to restorations Results from microleakage or residual caries Incidence- 16%Radiolucency depends on amount of demineralization& extent of restorationMesio/disto-gingival & occlusal margins- clearly seenUnder facial/ lingual restorations-difficult to detectMaterials like Ca(OH),composite & silicate cements
  46. 46. OTHER RADIOGRAPHIC SHADOWS Radiolucent Cervical Burn out: - Evident at the neck of tooth well demarcated above by enamel cap& below by alveolar bone level - It is triangular in shape being less apparent at the center of tooth -good alveolar bone height will enhance cervical burn-out Radiopaque zone beneath amalgam restorations Tin & zinc ions are released into underlyingdentin
  47. 47. Pitfalls Of Radiography 2 dimensional view of 3 dimensional object Radiographic depth of a lesion is often less than actual depth Overlapping of proximal surfaces on a radiograph Occlusal (incipient) caries of enamel difficult to detect Dental anomalies like hypoplastic pits mimic proximal caries Cervical burnout often confused with root caries
  48. 48. XERORADIOGRAPHY It is similar to photocopy machine Consists of Aluminum plate coated with selenium which provides a uniform electrostatic charge X- rays → selective discharge of particles → Latent image Processing unit: Latent image → positive image Very good Edge enhancement i.e., differentiating areas with different densities Twice more sensitive than D speed film, but equivalent to E speed film Disadvantages: Electrostatic charge may cause patient discomfort Processing to be completed by 15 minutes
  49. 49. DIGITAL IMAGING A digital image is an image formed & represented by a spatially distributed set of discrete sensors & pixels 2 types of non- film receptors Direct digital imaging – digital image receptor Indirect digital imaging – video camera for forming digital images of a radiograph Two types of detectors are used in Direct digital imaging Photostimulable phosphor ( PSP) –barium fluorohalide Charged couple device (CCD) – silicon Image is stored on a computer
  50. 50. DIGITAL IMAGINGSchick System Digora System Trophy System
  51. 51. Manipulation of images1. Magnification2.Variable contrast3. variable density4. Labeling important information5. Highlighting and colorizationAdvantages: 1.Images are available in seconds 2. Exposure is reduced 50-90% 3. Image size, contrast and density can be manipulated to improve interpretation 4. Record keeping is vastly improved. All films are labeled, filed and retrieved easily. Duplicate hard copies are the same as originals and simple to make 5. Provision of teletransmission
  52. 52. SUBTRACTION RADIOGRAPHY Structured noise is reduced in order to increase the detectablity of changes in the radiograph Structured noise refers to the information on the radiograph which have not diagnostic value It requires 2 identical images. The subtracted image is a composite these two, representing a difference in their densities Sensitive enough to detect changes of 0.12 mm 90% accurate in detecting mineral loss of 5% Black end of gray scale suitable for proximal & recurrent caries Contrast can be enhanced with color aid.
  53. 53. COMPUTER IMAGE ANALYSIS Softwares have been developed for automated procedures which are able to overcome the short coming of human eye Software supports an operation whereby a threshold is set up by the examiner which determines the program’s display of lesion probability Tuned Aperture Computed Tomography (TACT) involve the tomosynthesis of structures in 3D thereby increasing the accurate detection of caries Useful for monitoring carious lesion Increased sensitivity but decreased specificity
  54. 54. DYES FOR CARIES DETECTION They selectively complex with carious tooth structure which is later disclosed with the help of fluorescence Aids in both quantitative & qualitative analysis of the lesionDYES FOR ENAMEL CARIES: Procion: N2 & (OH) groups irreversibly complex with caries Acts as a fixative Calcein: complexes with calcium & remains bound to the tooth Zyglo ZL-22: fluorescent tracer dye, not used in vivo Brilliant blue: 10% aqueous Brilliant Blue, not used in vivo
  55. 55. DYES FOR DENTIN CARIES: 1% acid red 52 in propylene glycol complexes specifically with denatured collagen, hence used to differentiate infected and affected dentin Iodine penetration method (Pot iodide) for evaluating enamel permeabilityDISADVANTAGES• Dye staining and bacterial penetration are independent phenomena, hence no actual quantification• They also stain food debris, enamel pellicle, other organic matter• Dye aided carious removal- laborious• Stains DEJ
  56. 56. FIBEROPTIC TRANSILLUMINATION Different index of light transmission for decayed & sound tooth. Decayed tooth structure has decreased index & appears dark The tooth is illuminated using fiberoptics Have a high level intra & inter-examiner variability Digital imaging FOTI introduced, images captured by a CCD camera & fed into the computer for image analysis DIFOTI can detect caries on all types of teeth & also detect incipient & recurrent caries before their visibility on radiographs
  57. 57. ELECTRIC MEASUREMENTS FOR CARIES First proposed by Magitot in 1878 Tooth demineralization due to caries process causes increased porosity of tooth structure. This porosity contains fluid containing ions. This leads increased electrical conductivity, conversely, leads to decreased electrical resistance or impedance ECM device uses a fixed-frequency (23 Hz)alternating current which measures ‘bulk resistance’ of tooth
  58. 58.  Two systems Vangaurd system – 25 Hz – ordinal scale of 0 –9 Caries meter L – 400 Hz – 4 colored lights green –no caries yellow – enamel caries orange – dentin caries red –pulp involvement ECM limited to occlusal sites.ECM to H/P- 97% accuracy Cannot be used where amalgam filling is present Materials have different responses at different frequencies. Electrical Impedance Spectroscopy (EIS) operates over different frequencies & thus determine more accurately these differences. EIS can be used on both occlusal & proximal surfaces
  59. 59. Factors affecting electrical measurements1. Porosity2. Surface area3. Thickness of the tissues4. Hydration of enamel5. Temperature6. Concentrations of ions in the dental tissue fluids
  60. 60. RECENT ADVANCES IN CARIES DETECTION Research in the past two decades has lead to the development of new technologies that asses changes in fluorescence of enamel & dentin due to loss of mineral Benedict- 1929, normal teeth fluorescence Optical methods used are Quantitative light- induced fluorescence- QLF™ Infrared laser fluorescence - DIAGNOdent
  61. 61. ORIGIN OF FLUORESCENCESOUND ENAMEL: Baseline fluorescence is a result of inorganic matter & organic molecules Whiter teeth < darker teeth Fluorescence is a result of absorption ie, electrons move to higher states following absorption & fall back to their original states , emitting energy in form of light False positives: Calculus Composite restoration Remnants of polishing paste Stains
  62. 62. CARIOUS ENAMEL: Light scattering in lesion- light path shorter than that in enamel Light scattering acts as a barrier for the excitation light penetrating dentin Besides scattering of light, bacteria & their metabolites can contribute to fluorescence Proved by agar diffusion test Bacterial metabolites like protoporphyrins &meso- porphyrins produce intense fluorescence in red spectral region
  63. 63. Quantitative Light-induced Fluorescence Detection of carious lesion & quantifying mineral loss Argon ion laser(488nm) / Xenon arc lamp Blue light transmitting filter ↓ Fluorescence of enamel- demineralized areas appear as dark spots ↓ Passes thro’ high pass filter ↓ Captured on CCD ↓ Transferred to computer thro’ a frame grabber
  64. 64. • Hardware consists of: measurement probe – transmits monochromatic light Control unit – illumination device & imaging electronics Computer fitted with frame grabber – digitalize image from CCD• Qlf software for quantitative image analysis Lesion Area in mm2 Lesion depth in percentual loss of fluorescence (DF%) Lesion volume in nm3 (DQ)• Good reliability & reproducibility
  65. 65.  acquiration of measurement results with high precision and repeatability; easy use, reliable software measurement cycles The contrast between demineralised enamel and sound enamel has almost increased by a factor ten other things can be detected and quantified also, like dental plaque, calculus, and staining
  66. 66. Applications: Quantify in situ effects of fluoride treatments on demineralization of enamel lesion Monitor caries activity in orthodontic patient Evaluative caries preventive measures in caries prone patients Longitudinal quantification of incipient caries lesion on smooth surface QLF technology must be combined with visual examination in order to detect hypocalcified area due to development defects, fluorosis
  67. 67. DIAGNODENT - KAVO Spectral investigation of carious teeth revealed that good contrast between sound and carious enamel Fluorescence: carious teeth > sound teeth Intensity of fluorescence: 655nm < 488nm (QLF) But contrast between sound & carious tooth is better in 655nm Infra-red rays are less absorbed by enamel , hence penetrate deeper into dentin & fluoresce carious dentin
  68. 68. Component parts: Laser diode – 655nm, modulated at 1mW peak power - excitation light source - modulated to eliminate long λ ambient light also passing thro’ the filter Photodiode + long pass filter - detector - transmission >680nm long pass filter – absorbs back scattering Optical fiber – transmit excitation light - bundle of 9 fibers arranged concentrically around the optical fiber Digital display – quantitatively analyze fluorescence
  69. 69.
  70. 70. Procedure.1. Clean tooth surfaces preferably with an air polishing device (e.g. PROPHYflex) to completely remove plaque, stains and calculus from fissure areas.2. Dry the tooth.3. Perform clinical examination4. Diagnose and evaluate quantitative measurement of DIAGNOdent
  71. 71. Use of DIAGNOdent:  Baseline value: record fluorescence of sound spot on the smooth surface of tooth. This value is the subtracted electronically from the fluorescence on the site to be measured  Occlusal tip & smooth surface tip  Maximum fluorescence value is indicated by rising tone  Decision making for operative intervention  set peak value at 30, ↓sensitivity but ↑specificity safety fraction for stained fissures/ calculus
  72. 72. Interpretation of values: Display Therapy: value: 0 - 14 No special measures. 15 - 20 Usual prophylactic measures. 21 - 30 More intensive prophylaxis or restoration: indication is dependent on  •caries activity. •caries risk. •recall interval, etc. from 30 Restoration and more intensive prophylaxis.
  73. 73. Uses of DIAGNOdent:  To measure both sensitivity & specificity of lesions  Detection of occlusal & accessible smooth surface caries  Decision making for operative intervention  Reproducible method for caries detection epsl at D2 & D3 levels  Longitudinal monitoring of caries Disadvantages:  • Measures false positives • Not useful in approximal caries detection • Lack of repositioning systems that may affect reproducibility of results
  74. 74. CARIES RISK ASSESSMENT Clinical examination neither predicts caries activity nor susceptibility Certain simple reliable lab tests can facilitate this,which is important because; - need & extent of personalized preventive measures - index for therapeutic measures - patient education - manage progress of restorative procedures - identify high risk groups / individuals www.indiandentalacademy .com
  75. 75. Requisites of tests Correlation between predicted & actual caries development Reliability & validity Simple to perform Quick results Measurement of mechanism involved in caries process www.indiandentalacademy .com
  76. 76. Caries activity Vs Caries susceptibility Caries activity refers to the increment of active lesions Susceptibility refers to inherent propensity of the host & target tissue affected by caries Most of the tests measures the former Caries activity tests measure either the quantity of specific bacterial group or their ability to produce acids. Hence this must be coupled with clinical examination prior to treatment planning. www.indiandentalacademy .com
  77. 77. Caries Activity TestsLactobacillus colony count test: Introduced by Hadley in 1933 Stimulated saliva collected & diluted with distilled water. Spread evenly on Rogasa’s SL agar plate. Incubated at 37°C for 3-4 days. No.of colonies developed counted No.of org/ ml Degree of caries activity 0 – 1000 Little / none 1000 – 5000 Slight 5000 – 10,000 Moderate > 10,000 marked www.indiandentalacademy .com
  78. 78. Calorimetric Snyder test: Measures the ability of micro organisms to form organic acids in carbohydrate 0.2 ml of patient’s saliva is pipetted into melted medium at 50°C. Incubated for 72 hrs. medium contains bromocresol green which changes color from green to yellow in the range of pH5.4 – 3.8 24 hrs → 48 hrs → 72 hrsIf yellow If yellow If yellowMarked caries Definite caries Limited cariesactivity activity activityIf green If green If greenObserve – 48hrs Observe –72hrs Caries inactive www.indiandentalacademy .com
  79. 79. Swab Test: Developed by Grainger in 1965 Based on the principle of Snyder test Swab is taken from the teeth & incubated in medium pH change after 48 hrs is read on a pH meter pH 4.1or less Marked caries activity pH 4.2 – 4.4 Active pH 4.5 – 4.6 Slightly active pH 4.6 0r more Caries inactive www.indiandentalacademy .com
  80. 80. Salivary buffer capacity: Tests the buffering capacity of bicarbonate ion in saliva 2 ml of stimulated saliva + 4 ml of distilled water Set up is placed under paraffin seal to prevent loss of volatile bicarbonate ion Micro-burette & micro glass electrode are introduced under the seal & the amount of 0.5 N HCl required to bring saliva to pH 5 is measured Samples requiring less than 0.45 ml of HCl indicate low buffering capacity & vice-versa www.indiandentalacademy .com
  81. 81. Saliva-Check BUFFER: Checking pH level & salivary buffering capacity of resting & stimulated saliva The kit consists of pH strips 5.0 – 8.0 & buffering strips Resting salivary analysis is made by asking the patient to expectorate any pooled saliva Stimulated saliva is obtained by asking the patient to chew paraffin wax for 30 sec Samples collected are tested with the strips available in the kit Buffer strips contain 3 rows test pads. Salivary sample is pipetted onto each of these pads. Color change noted after 5 min www.indiandentalacademy .com
  82. 82. pH analysis: Results in 10 seconds Color change pH range Red 5.0 – 5.8 Yellow 6.0 – 6.6 Green 6.8 – 7.8Buffering capacity analysis: Results 5 min Color change on each of the test pad is noted &points are assigned accordinglyGreen – 4 pts Blue/ Red – 1 ptGreen/ blue – 3 pts Red – 0 pt www.indiandentalacademyBlue – 2 pts .com
  83. 83. Interpreting results: Combined total Buffering ability 0–5 Very low 6–9 Low 10 – 12 Normal/ high www.indiandentalacademy .com
  84. 84. Alban test: Simplified substitute of Snyder test Alban test medium – 60 g Snyder test agar + 1 liter water Patient to expectorate saliva in test tube containing Alban test medium. Incubated at 37°C upto 4 days Tubes are observed daily for: - change of colour from green to yellow - depth in the medium to which change has occurred www.indiandentalacademy .com
  85. 85. Scale for scoring: color change is noted After 72 hrs/ 96 hrs of incubation1. No color change2. Beginning of color change = + (from top to bottom)3. One half color change = ++4. ¾ color change = +++5. Total color change = ++++ www.indiandentalacademy .com
  86. 86. Caries Susceptibility TestEnamel solubility test: When glucose is added to saliva containing powdered enamel, organic acids are formed. This will decalcify enamel leading to an increase in soluble Ca ions Amount of Ca obtained gives a direct measure of caries susceptibilitySalivary reductase test: Measures the activity of reductase enzyme in salivary bacteria Kit commercially available- Treatex Salivary sample mixed with Diazoresorcinol dye www.indiandentalacademy .com
  87. 87.  Color changes are tabulated after 15 min Color Caries conduciveness Blue in 15 min Non- Conducive Orchid in15 min Slightly Conducive Red in 15 min Moderately Conducive Red immediately on Highly Conducive mixing Colorless in 15 min Extremely Conducive www.indiandentalacademy .com
  88. 88. CARIOGRAM Introduced by Bratthall to assess factors contributing to development of caries Consists of a pie diagram divided into 5 sector - Green – estimation of the chance to avoid caries - Dark blue – Diet - Red – bacteria- amt of plaque & S. mutans - Light Blue – Susceptibility- combination of F program Saliva secretion & buffering capacity - Yellow – Circumstances- past caries experience & related disease www.indiandentalacademy .com
  89. 89. MODERN CONCEPTS OF CARIES MEASUREMENT Modern means accepted in dental research & practice Concepts of caries measurement must be seen as theoretical frameworks based on both synthesized evidence & contemporary practice Caries; to be seen as a continuum of disease states ranging from subclinical, subsurface changes to more advanced stages with microscopic & later macroscopic cavitation & finally significant involvement of dentin Caries Measurement is how defined stages of caries process are quantified, graded & recorded
  90. 90. This involves 7 linked steps:1.Caries detection: - essentially a yes / no decision - result depends on: true state of tooth surface, detection potential of method used method’s accuracy & reliability influence of detection threshold2. Lesion measurement: - Diagnostics threshold- What is diseased & what is sound? - this is given by the ‘Iceberg of dental caries’
  91. 91. Iceberg of dental caries with diagnostic threshold www.indiandentalacademy .com
  92. 92. 3. Lesion monitoring by repeated measures: - used at a series of examinations when lesions are less advanced than that which requires operative intervention - helps in decision making for preventive care aiming at arrest or reversal of the lesion4. Caries activity measurements: - poorly developed as compared to other aspects - ideally be able to measure dynamic activity of individual lesion to differentiate its current behavior from historical signs of past caries progression
  93. 93. 5. Diagnosis, prognosis & clinical decision making: - information from steps 1-4 are synthesized - helps to derived stage of lesion & patient circumstances which would translate into restorative treatment decision6. Interventions / Treatments: -this is again given by ‘Iceberg of dental caries’ & contemporary treatment need/ advice
  94. 94.
  95. 95. 7. Outcome of caries control / management: - success in arresting & reversing initial lesion as well as in preventing the development of cavitated dentinal lesions
  96. 96. POTENTIAL NEW DIAGNOSTIC MODALITIES Light is a suitable tool for the study of teeth.Disrupted surfaces scatter light passing into tooth.In addition to scattering, changes may includeabsorption & fluorescence MULTI-PHOTON IMAGING INFRARED THERMOGRAPHY INFRARED FLUORESCENCE OPTICAL COHERENCE TOMOGRAPHY ULTRASOUND TERAHERTZ IMAGING
  97. 97. MULTI-PHOTON IMAGING QLF uses single ‘blue’ photon to excite fluorescence MPI uses many infrared photons thus increasing the chance of absorption of atleast two photons resulting in fluorescence Ultra-short pulses (100fs) of 850nm laser light generated at 200MHz results in two photon effect, which is recorded in a particular focal plane Fluorescence for sound tooth > carious tooth Plane of focus can be moved thro’ the lesion & record sectional images to form a 3D image Caries appears dark in a fluoresced tooth. Negative images can be used to highlight the lesion
  98. 98.  MPI can measure lesion depths to 500 µ Gives a quantifiable measure of mineral loss in 3 dimensions Decreased laser power used in MPI ensure low risk of photo-toxicity to pulp & increased depth of penetration Only in-vitro studies conducted. Requires future research to develop laser equipment used for clinical practice
  99. 99. INFRARED THERMOGRAPHY Described by Kaneko et al in 1999. Measures lesion activity not presence / absence of caries This measures the thermal changes when fluid is lost from a lesion by evaporation. Thermal energy emitted by sound tooth structure is measured with that emitted by carious tooth structure Indium / antimony thermal sensors, detect temperature changes close to 0.025°C Source to sensor distance – 20cm, & time taken to capture an image – 2 min Not used intra-orally : variations of temp in mouth due to respiration or fluid evaporation from tissues Detection of proximal caries - questionable
  100. 100. INFRARED FLUORESCENCE Seldom reported. In theory, tooth is exposed to light with a λ between 700 & 15,000nm. Barrier filters are used to observe any fluorescence Longbottom suggested that this technique discriminates bet sound & carious tooth structure (unpublished) Further studies are required to determine - intensity of fluorescence signal - heating effects on pulp due to↑ penetration & ↓ scattering - sources that provide specific coherent irradiation - infrared sensitive detector – CCDs / films
  101. 101. OPTICAL COHERENCE TOMOGGRAPHY  This is used for imaging transparent & semi transparent structures  OCT uses light & measures scattering & hence depth of penetration for imaging technique  Based on interference of light  Uses Super Luminescent Diodes as light source. Spectral bandwidth of light source determines depth of resolution  Measure of scattering on single point on the tooth is called an “ A-scan”. Several A-scans along a line gives a tomogram called a “B-scan”
  102. 102. For an A-scan to be produced, light from source passes thro’ a beam splitter ↓two coherent beams produced- sample beam & reference beam ↓sample beam hits the tooth & gets scattered, part of it get back scattered ↓the reference beam hit a movable mirror & reflected back- here it is combined with the back- scattered beam ↓ degree of interference is read by a photo detector
  103. 103.  By moving the beam thro’ 20µ on the sample results in a tomographic scan / B- scan Wavelengths of 840 to 1310nm have been used resulting in imaging depths of 0.6 to 2 mm Depth resolution varies from 10 - 17µ Development of intra-oral hand piece for OCT, underway OCT has also be used in analysis of restoration tooth interface Has its’ implication in non-invasive diagnosis of secondary caries
  104. 104. ULTRASOUND• This has been used for the past 30 years & has undergone tremendous change for the past 5 yrs• Sound waves are pressure waves that have the ability to travel thro’ gases, liquids & solid• Ultrasound waves have frequency > 20,000 Hz that undergo scattered, reflected, refracted & absorbed• There is a difference in acoustic impedance between 2 surfaces at the interface which is interpreted by the difference in the reflected sound waves• The amount of reflected sound waves provide information of the reflecting interface & time taken for sound to be reflected provide info of the position of reflecting surface under study
  105. 105. • Ultrasound waves are produced by AC applied to a piezo-electric crystal. This travels thro’ a coupling medium which delivers waves to the surface. Those used in dentistry are water / glycerin• Detection of DEJ / dentin-pulp interface – the waves are delivered directly to the surface• Detection of caries – waves travel along the interface of air & enamel• Flexible tips, wedge shaped for proximal areas• Effective in detecting proximal caries that were missed on radiograph• Strength of reflected waves: cavitated lesion > non- cavitated• Also detects dentin involvement in intact surface enamel
  106. 106. TERAHERTZ IMAGING Uses waves of terahertz frequency – 1012 Hz & λ - 250µ Short enough to provide reasonable resolution but long enough to prevent loss of information due to scattering Photo-conducive emitters / certain crystals like Zn tellurite when exposed to short pulses of visible light/ infrared light, emit waves of terahertz frequency Reflected waves are detected with the help of photo- conducive detectors like a CCD Adverse thermal effects thought to be unlikely Low signal : noise ratio facilitates clear imaging But long wavelength can reduce spatial resolution Terahertz waves are strongly absorbed in water, which may complicate its use in the oral cavity
  107. 107. Conclusion “ the complete divorcement of dentalpractice from studies of pathology of dentalcaries, that existed in the past, is ananomaly in science that should notcontinue. It has the apparent tendencyplainly to make dentists mechanics only”
  108. 108. References Art & science of operative dentistry – Sturdevant 4th edition Understanding Dental Caries – Gordon Nikiforuk Textbook of Clinical Cariology – Thylstrup 2nd edition Operative Dentistry - Schwartz Principles of Radiology – White & Phoroah Essentials of radiology – Eric Whaites Journal of dental research – September 2004 Caries Research Journal – 2000-04 www.indiandentalacademy .com
  109. 109. References DCNA- Cariology – Vol 43, Oct 1999 Caries diagnosis, Risk assessment & management- - School of dentistry, University of Michigan Textbook of paedodontics – Shoba Tandon Textbook of operative dentistry – Vimal Sikri Essentials of community dentistry – Soben Peter www.indiandentalacademy .com
  110. 110. THANK