1. Diagnostic methods
   1. Traditional methods
      1. Patient complaint
      2. Meticulous clinical examination
      3. Tactile examination
      4. Radiographic examination
   2. Recent methods ( Identifies the early changes in carious lesions)
      1. Xeroradiography
      2. Digital radiographic methods
      3. Computer aided radiographic method
      4. Digital subtraction radiography
      5. Digital fiberoptic transillumination (DIFOTI)
      6. Dyes for detection of caries
      7. Electrical conductance measurements
      8. Endoscopic filtered fluorescence method
      9. Quantitative laser fluorescence
      10. Alternating current impedance spectroscopy technique (ACIST)
      11. Ultrasonic imaging
      12. Optical coherence tomography (OCT)
2. Xeroradiography
   1. Image is recorded on an aluminium plate coated with a layer of selenium particle
   2. Advantages
      1. Edge enhancement Less radiation exposure No wet processing Both +ve and -ve prints are possible
   3. Disadvantage
      1. Expensive Development process should be completed within 15 minutes Electric charge over the film may cause discomfort to the patient
3. Digital radiographic method
   1. Superior means of detecting caries than conventional radiographs
   2. Methods of obtaining
      1. Video recording & digitalization
      2. Direct digital radiograph
   3. Advantages
      1. Reduced radiation dose Instant image visualization No need of darkroom No processing error Image can be magnified Contrast and density of image can be enhanced
   4. Disadvantages
      1. Expensive Small image areas
4. Digital fiberoptic Transillumination (DIFOTI)
   1. Combines fiberoptic transillumination and a digital CCD camera
   2. Advantages
      1. Instantaneous image projection Image quality is easy to control Can detect incipient and recurrent caries very early Non- invasive
   3. Disadvantages
      1. Does not measure the depth of the lesion Difficult to distinguish between deep fissure, stain and dental caries
5. Electrical conductance measurements
   1. Sound enamel is an insulator due to its high inorganic content
      1. Carious enamel has a measurable conductivity which increase with the degree of demineralization
   2. Devices used
      1. Vanguard electronic caries detector Caries meter
   3. Advantages
      1. More accurate in diagnosing early occlusal caries than visual method, radiograph or FOTI Can monitor the progress of caries
   4. Disadvantages
      1. Hypo mineralized areas, enamel cracks and cause misleading readings Time consuming procedure Requires the use of sharp metal explorers which can cause traumatic defects in pits and fissures
6. ALTERNATING current impedance spectroscopy technique (acist)
   1. Promising technique for caries detaction
      1. Characterizes the electrical properties of the tooth and lesion by scanning multiple frequencies of alternating current
      2. Change in impedance( the resistance of alternating current) of a sample during excitation with an alternating current voltage is measured Impedance for healthy tooth very high due to relatively low ionic content As the decay progresses impedance decreases
   2. Cariescan
      1. Offers the earliest possible detection of caries using ACIST Accurate and repeatable
7. Quantitative laser fluorescence (QLR)
   1. Related to endoscopic filtered fluorescence method
      1. Laser-induced fluorescence can be measured to quantify tooth demineralization
      2. Argon laser- 488nm wavelength DIAGNODENT- 665nm wavelength diode lase
   2. Advantages
      1. Reliable method for diagnosis of early occlusal caries Convenient and fast method
   3. Disadvantage
      1. Expensive Cannot differentiate between caries, hypoplasia stains and calculus Cannot differentiate between active or inactive lesions
8. OTHER DIaGNOSTIC Methods
   1. Computer aided radiographic method
      1. Provides graphic visualization of the size & progression of carious lesion
      2. Advantages- Identifies small carious lesions Help in monitoring the carious process Disadvantages- Time consuming More expensive
   2. Subtraction radiography
      1. Image which are not of diagnostic value in a radiograph are reduced so that the change in the radiograph can be precisely detected
      2. Advantages- Proximal caries can be visualized better Assesses the progression of the carious Disadvantages- Expensive
   3. Dyes for detection of caries
      1. Dyes are useful to detect carious dentin Stains infected demineralized dentin while the affected dentin remains unstained Basic fuchsin considered to be carcinogenic 1% acid red dye in propylene glycol- currently used
   4. Endoscopic filtered fluorescence method
      1. When tooth is illuminated with blue light in the wavelength of 400-500nm, sound enamel and carious enamel demonstrate different fluorescence When this is viewed through a filter, white spot lesions appear darker than sound enamel
   5. ultrasonic imaging
      1. Detect early carious lesion on smooth surfaces Normal enamel produces- no echoes initial white spot lesion- weak surface echoes Cavitated area- Echoes of higher amplitude May be more sensitive than visual, tactile or radiographic methods for detecting early lesions
   6. Optical coherence tomography
      1. Non invasive Creates cross sectional image of internal tooth tissues
9. Minimal intervention dentistry
   1. Principles
      1. Early diagnosis of dental caries Assessment of individual caries risk Disease control by remineralization of incipient carious lesions Minimally invasive treatment Repair, rather than replacement of defective restorations Periodic follow up to assess the outcome of caries management strategies
   2. Minimally invasive treatment
      1. Smaller dimension microcavities are prepared
      2. Technologies used Air abrasion, sono abrasion, chemo mechanical caries removal, Lasers
   3. Air abrasion
      1. Works by spraying a powerful stream of a focused narrow beam of aluminium oxide (Al2O3) Particle size- 20-50 micron Pressure- 40-140 psi Cuts enamel, dentin and cementum effectively
      2. For widening pits and fissures Minimal class 1 and 2 preparations For abrading the surface of old composite restoration prior to repairing them with new composite For abrading ceramic or cast restorations for bonding Contraindications Extensive cavity preparations as for cast restorations Crown or veneer preparations
      3. Advantages No need for local anaesthesia Does not generate , vibrations or noise Conserves tooth structure Well tolerated by the patient Disadvantage Does not remove soft caries Cannot prepare precise cavities needed for large restorations Al2O3 dust generated during the procedure can affect patients with chronic respiratory problems like asthma can damage the adjacent tooth while performing class 2 cavity preparations Expensive
   4. Sonic abrasions
      1. Sonic handpiece works by vibration of tips Opening pits and fissure for sealant restorations Minimal preparation of incipient class2 cavities without damaging the adjacent tooth
   5. Chemo mechanical caries removal
      1. Chemical softening of carious dentin followed by gentle excavation
      2. Caridex- used earlier Consits of - 1% NaOCl 0.1M aminobutyric acid Glycine NaCl and NaOH
      3. Carisolv- more effective consits of- NaOCl- 0.5% 3 amino acids (Glutamic acid, Leucine, Lysin) Carboxymethylcellulose gel Nacl, NaOH Erythrosine (Red colrant)
      4. Advantages- Relatively painless, no need for local anesthesia Removes only carious dentin Creates a better substrate for adhesive bonding Disadvantage- Time consuming Expensive
   6. Lasers
      1. For cavity preparation, hard tissue lasers in the infra red area of the electromagnetic spectrum are used
      2. Commonly developed lasers for this purpose Er:Cr:YSGG- 2780nm Er:YAG (2490nm)
      3. Advantages- No vibrations Prepare conservative cavity preparations Less traumatic for patients No need for anaesthesia Disadvantages- Cannot be used for large cavity preparations Time consuming Expensive