25. Once the root has been located and the initial resection accomplished, methylene blue dye (Fig. 1) is dabbed onto the
amputated root surface with a sterile cotton pellet for 1 to 2 min. The surgical area is then washed with sterile saline
solution.
The remaining dye will stain not only the internal root canal anatomy exposed by the resection but also the
periodontal ligament
Methylene blue dye has also been used in an earlier research study to determine the incidence of isthmuses
connecting two canals in single roots Study showed that isthmuses were present in 60% of the mesial roots and 15%
of the distal roots of mandibular molars as well as in 30% of the mesiobuccal roots of maxillary molars
The dye can also be used to delineate apical (vertical) fractures, but such defects are usually defined by fiber-optic
transillumination. Vital staining with methylene blue is also helpful with surgically enucleating cysts.
46. Holm Reuver’s diaphanization technique applied to different teeth showing the complexity
of the internal anatomy of (a) one mandibular incisor and (b–f) five mandibular molar
47. Holm Reuver’s diaphanization technique
complexity of the internal morphology of a maxillary molar apical complexity of the root canal system
48. Holm Reuver’s diaphanization technique applied to a maxillary
molar tooth
Depicting a massive extra canal invasive resorption (ECIR) on the buccal aspect of the palatal root
In fact, one of fluorescein’s derivatives is eosin, which is used as an agent for staining eosinophils found in the blood stream. Similarly, fluorescein has also been used to stain organic matter remaining inside root canals.
Under a blue light source, fluorescein changes colour from yellow to fluorescent green, thus enhancing observation of the dye effect.
The objective of this study was therefore to ascertain whether use of a 1% sodium fluorescein solution on the pulp chamber floor of human maxillary first molars and a cobalt blue filter coupled to a DOM enable the location of a greater number of root canals, compared to detection with the naked eye or with the DOM alone.
Mechnism -Under a blue light source, fluorescein changes colour from yellow to fluorescent green, thus enhancing observation of the dye effect.
In this technique described for disclosing root canal orifices1% sodium fluorescein dye is applied to the pulp chamber floor and easily absorbed by organic tissue remnants. The pulp chamber is then copiously rinsed with water and examined using a DOM. The DOM light is then switched off and the region is lit with ultraviolet light from a photopolymerisation unit to examine any fluorescent green areas highlighting the root canal orifices Although useful, this traditional technique has the following disadvantages: it is not possible to use the DOM light (for illumination) concomitantly with the photopolymerisation unit light (for detection); the endodontist cannot keep both hands free for inspection, or requires the aid of an assistant in order tokeep both devices positioned, and a shadow may be cast because of the lateral position of the ultraviolet light source (since the DOM has to occupy the axial position).
The modified solution developed in the present study proposes the use of a cobalt blue filter coupled to the DOM, enabling the root canals identified by fluorescein to be visualised directly through the DOM lenses, without having to switch it off and dispensing with the need for a photopolymerisation device. The filter is cobalt blue in colour and has low light transmittance, in the 500 nm to 650 nm range. It can be made of plastic, acrylic or glass, be circular or square in shape, and be coupled either externally or internally to the DOM optical head.
Hypaque-M, a radiopaque contrast medium consisting of high concentration, high viscous aqueous solution of two iodine salts containing diatrizoate meglumine and sodium. It has a pH of 6.5 to 7.7 and is stable at room temperature.
Crystals may form in the solution when it is cool but dissolve readily when heated to body temperature for administration.
It is principally used in medical radiography as a high-contrast injectable dye in angiography, arteriography, urography, and nephrotomography
It was introduced intrapulpally into each tooth using a syringe and a #15 k-file to ensure that the media reached the apex
The presence and location of accessory/lateral canals was then determined.
The purpose of this study was to investigate the use of the RVG-S, with and without the use of radiopaque contrast media, in the detection of accessory/lateral canals in extracted human teeth and compare its efficacy with that of standard E-speed radiographic film.
RVG consists of a scintillator/charged coupled device with digital signal input into a display processing unit. The image can be stored in the computer, and enhancements including magnification and reversal performed
Root canal anatomy in the human dentition is complex. Although the apical foramina of the roots are the principal pathways between the pulp and the periodontal ligament (PDL), patent lateral and accessory canals may also exist.
A lateral canal is a direct anatomical communication to the PDL and is frequently perpendicular to the main canal.
Accessory canals are found most commonly in the apical region of the tooth and branch from the main canal to a secondary apical opening. The incidence of lateral/ accessory canals reportedly increases in posterior teeth, toward the apical third of the root and with pulp vitality
Lateral canals are not usually detected on intraoral radiographs. It is usually detected only after root canal obturation with radiopaque materials that lateral canals are identified
A form of aqueous solution of iodine salt, diatrizoate, has been injected to aid in the diagnosis of periapical lesions, to determine pathways of anesthetic injection and in apexification procedures Alacam evaluated the radiopaque properties of different iodine radiopaque contrast materials mixed with calcium hydroxide powder. They found that the addition of diatrizoate and iothalamate iodine salts substantially increased the radiopacity of calcium hydroxide and suggested they be used as additives to increase the radiopacity and, therefore, the location of these pastes in root canals.
Tang and Stock (10) used a radiopaque contrast material to quantitatively compare the effect of instrumentation on the shape of root canals
Results – plotted
Highest sensitivity is shown by the use of RVG-magnified images with and without the use of Hypaque in RVG normal and inverse modes However, the use of RVG also increases positive predictive value. Highest positive predictive value was shown for RVG normal with the use of Hypaque ,introduction of radiopaque contrast media increased sensitivity of normal and inverse RVG-S images. Use of zoom RVG images produced the highest sensitivity of all modalities tested
though the results demonstrate some interesting modality and treatment effects, they clearly indicate that the use of the RVG digital intraoral system with or without radiographic contrast media does not assist the clinician in the detection of lateral/accessory canals , also magnification of high-resolution images reduced detection of accessory/lateral canals by contrast media.
The use of soluble iodine containing radiopaque contrast media is potentially extremely irritating if extended beyond the tooth apex. The diatrizoates are organic iodine containing molecules which have high solubility and form stable solutions with high radiodensity. They are the least toxic type of iodine containing radiopaque media The media is inexpensive, sterile, has prolonged shelf life, and is readily available. These advantages led to the choice of this agent for potential use as a contrast media in endodontics.
However, the use of this material did not greatly improved the detection of accessory/lateral canals. However, it is interesting that the use of Hypaque did increase the sensitivity of the RVG modality except for magnified image
In dentistry, methylene blue dye In endodontics, it is used most often in marginal leakage studies to stain and locate those areas of the root canal system not sealed by the obturating material.
Vital staining with methylene blue dye has been used to selectively stain tissue during molar surgery when the ability to differentiate tooth from bone is hindered by poor visibility, excessive bleeding, or unusual root anatomy.
A and B, Radiographic and clinical appearance of an incisive canal cyst. The gutta-percha (GP) cone delineates the sinus tract radiodiographically.
C Palatal flap reflected (first bicuspid to first bicuspid) exposes stained cystic tissue .. D, Resected cyst with the inner lining stained blue shining through the cyst wall.
Dental diaphanization or transparency methods, useful tool for understanding the internal anatomy of human teeth
useful to study the anatomy of the root canal system ,allows for a three-dimensional visualization of the internal structures of the tooth. it is economic, it does not need special devices, it is relatively easy to execut
Dental diaphanization has been frequently used to observe several anatomical features of the root canal system including the presence and amount of main canals lateral canals additional canals such as MB2 in mesiobuccal roots of maxillary molars or middle mesial canals in mesial roots of mandibular molars apical ramifications loops split canals connecting canals, isthmuses
Apart from the anatomical structures, dental diaphanization can also be used to assess apical diameters thickness of the cement at apical level and location and shape of the cement-dentin-canal (CDC) junction and of the apical constriction
(a–c) Measurements of the main and lateral canals;
(d–g) measurement of the cement layer thickness;
(h–j) determination of the apical constriction position;
(j) assessment of the accuracy of electronic apex locators
(k–l) evaluation of the quality of filling techniques
(m–n) observation of vascular distribution
Dr. Barrington advocated technique to use the existing pulpal tissue by using a contrast medium;
(b) the use of a contrast medium allows to observe anatomical structures of the root canal
(c) India ink used as a contrast agent may cover the outer surface of the root preventing correct visualization of the root canal
(d) complete leaching out of contrast agent into the dentinal tubules avoiding visualization of the canal system
(e) contrast dye stained the canals and the dentin losing overall contrast between dentin and canal system
(f) India ink leaching into the dentinal tubules washing out the appearance of the canal system
(g) penetration of India ink into the dentinal tubules prevents visualization of the lateral limits of the main canals
(h) the use of diluted paint as a contrast medium can allow a correct definition of the root canal boundaries
(o, p) mandibular first premolar cleared with the Barrington’s method using dental pulp as a contrast medium
(q–s) air injection technique used as a contrast medium
(t, u) unsatisfactory results from air injection technique
(v) biofilm of microorganisms used as a contrast medium
(a) When eugenol is used as a clearing agent, tooth is cleared but will present a yellow appearance
(b) the use of methyl salicylate as a clearing agent allows a more transparent appearance in comparison with the eugenol
(c) honey can also be used as immersion agent with acceptable result
(c–g) (d-h)
(a–c) An endodontically treated maxillary second premolar was extracted and made transparent revealing a complex apical anatomy
(d) file separation and missed MB2 in the mesiobuccal root of a maxillary left first molar
(e) root filled with silver point technique obturation
(f) mesial root of a mandibular right first molar filled with silver points
(g) root-filled maxillary second molar showing a missed MB2 canal
(h) distal root of a mandibular first molar filled with lateral condensation technique
(i) mesiobuccal root of a maxillary right first molar with a long-term infection showing apical root resorption and missed MB2 canal (j) root canal of a mandibular right second premolar filled with classical Schilder’s obturation technique
(k) root-filled mandibular first premolar with access closed with composite
(l) root canal filled with carrier-based obturation showing stripping of gutta-percha from carrier
(m) mesial root of a mandibular right first molar filled with lateral condensation technique with master gutta-percha cones dipped in eucalyptol
(a–d) Middle mesial canal dividing into two canals in the middle part of the root. Each one of the divisions is confluent with the main canals and has an independent foramen
(e) one of the main canals is divided into two canals at apical level. A middle mesial canal which ends in the division of the main canals can be also observed
(f) it is common to observe a widening of the middle mesial canals at the coronal or middle thirds of the root
(g–i) a middle mesial canal starts in one of the main canals and ends in the other.
There is also a recurrent canal at the level of the middle third and a calculus at the apical third of the root
(a, b) Independent middle mesial canal showing multiple transverse connections with the main canals
(c, d) presence of a calcification in the apical third of the canal
(e-g) main root canals in the mesial root of a mandibular molar connected by multiple transverse canals
(h) a wide canal is divided into three canals with independent foramens at the apical third; (i) magnification of image in (i) showing a canal calcification
