dentistry

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  • Temporary fillings are made of a soft material that is easily removed and replaced.
  • Endodontics
    A branch of Dentistry concerned with the morphology, physiology, and pathology of the human pulp and periradicular tissues
  • Endodontic Therapy
    • Deals with pulpal diseases and periradicular tissues
    • Allows removal of infected tissue from the root canal system
    • Pulp tissue is extirpated or debrided
    • Pulp chambers and canals are cleaned, disinfected, shaped, filled, and tooth is restored
    • Result: allows saving and retaining of teeth that would otherwise be extracted
    • Contraindicated if there is massive tooth destruction and if there’s a root fracture
  • Rationale
    1. If bacterial and by-product of pulpal inflammation has been reduced to a non-critical level of infection, it will effect a cure allowing resolution and repair of damaged periradicular tissue
    2. The extent of damage depends on the virulence of the MOs and on the host resistance
  • Goals of Endodontics
    • Saving natural teeth to health
    • Preserve occlusion and restore efficient mastication
    • Control pain and swelling
    • Speech and phonation
    • Aesthetics
  • Endodontic Procedures
    1. History taking and examinations are performed for correct diagnosis
    2. Access opening is made through the crown
    3. The pulp is removed with tiny instruments called nerve broaches
    4. A temporary filling is placed in the access opening to protect the root canal
    5. When completely clean and free of infections the root canals are filled and sealed
    6. A final restoration covering the crown is placed
    7. Etiology includes severe decay, fracture, traumatic injury, cracked or loose fillings, periodontal disease
  • Root Canal Morphology and Its Significance
  • Root canal treatment steps
    I. Diagnosis to know indication and case selection for root canal
    II. Treatment to guide us in all treatment procedures
    III. Prognosis to predict the outcome of the treatment
  • Root canal system
    The entire space in the dentin where the pulp is located
  • Parts of the root canal system
    • Pulp chamber with pulp horns
    • Root canals with canal orifice and apical foramen
  • Accessory canals are minute canals that extend in horizontal, vertical, or lateral directions from the pulp to the periodontium
  • Root canal system is a miniature version of the external anatomy of the tooth
  • The problem in the root canal system is its vast variability and the presence of irregularities
  • Determination of the Root Canal Configuration
    • If only one canal is present, it usually is located in the center of the access preparation
    • If only one orifice is found and it is not in the center of the root, another orifice probably exists and must be searched for on the opposite side
    • The closer two orifices are, the greater the chance the two canals join at some point in the body of the root
    • As the distance between orifices in a root increases, the greater is the chance the canals will remain separate
    • The more separation between orifices, the less the degree of canal curvature
    • If the first file inserted into the distal canal of a mandibular molar points either in a buccal or lingual direction, a second canal is present
  • Apical constriction is the portion of the root canal with the smallest diameter, found 0.5 to 1.5mm coronal to the apical foramen
  • CDJ is the point in the canal where cementum meets dentin, estimated to be approximately 1 mm from the apical foramen
  • Apical foramen is the rounded edge that differentiates the termination of the cemental canal from the exterior surface of the root, offset 0.5 to 3 mm from the anatomic apex
  • Vertucci’s classification of root canal morphology includes Type I to Type V based on the configuration of the canals
  • Types of root canal morphology according to Vertucci
    • Type I: One canal joins short of the apex to form one canal (2-1)
    • Type III: One canal leaves the pulp chamber and divides into two in the root; the two then merge to exit as one canal (1-2-1)
    • Type IV: Two separate, distinct canals extend from the pulp chamber to the apex (2)
    • Type V: One canal leaves the pulp chamber and divides short of the apex into two separate, distinct canals with separate apical foramina (1-2)
    • Type VI: Two separate canals leave the pulp chamber, merge in the body of the root, and separate short of the apex to exit as two distinct canals (2-1-2)
    • Type VII: One canal leaves the pulp chamber, divides and then rejoins in the body of the root, and finally separates into two distinct canals short of the apex (1-2-1-2)
    • Type VIII: Three separate, distinct canals extend from the pulp chamber to the apex (3)
  • Methods of studying the pulp
    • Grinding
    • Histological methods
    • Radiography
    • Clearing technique
    • Acrylic cast/Silicone injection
    • Computed Tomography
  • Ground Section
    1. Cutting the tooth structure longitudinally or cross-sectionally using a carborundum stone
    2. Disadvantages: it might destroy the real features of the anatomy
    3. Anti-curvature filling: File away from the curvature/thinnest area and towards the outer surface of the canal where there is bulk of dentin, prevents root perforation
  • Histologic Section
    1. Tooth is decalcified using hydrochloric acid and thinned down using microtome
    2. Stain is used then the slide is viewed under the microscope
    3. Disadvantages: risk of shrinkage of tooth anatomy
  • Radiograph
    1. Shows a two-dimensional picture of a three-dimensional object
    2. Disadvantages: only the mesio-distal dimension is seen but not the depth
    3. Tube-shift technique: SLOB
  • Clearing Technique
    1. Tooth is decalcified in 10% hydrochloric acid solution then injected with Methylene Blue and cleared with Methyl Methacrylate
    2. Gives a good idea of the canal irregularities
    3. Disadvantages: a little bit of shrinkage and the natural anatomy is not restored well
  • Acrylic Cast/Silicone Injection Technique

    Flowable resin is injected into the cavity and the tooth is dissolved away to expose the hardened internal anatomy
  • Computed Tomography
    1. Provides information of the root canal anatomy in three dimensions
    2. With high-resolution digital images
    3. Advantages: less px exposure to radiation, lack of distortion and magnification, good tool for px education
    4. Disadvantages: Expensive
  • Factors affecting root canal morphology: Age - Physiologic deposition of secondary dentin causes the pulp to become smaller as one ages, faster deposition along the roof and floor of the pulp chamber
  • Factors affecting root canal morphology: Irritants - Tertiary dentin deposition
  • Factors affecting root canal morphology: Irritants - Internal resorption, an indicator of pulpal pathosis, results if clastic cells within the pulp are active, if it continues, forms a perforation necessitating tooth removal
  • Factors affecting root canal morphology: Calcifications - Radiopaque structures in the pulp chamber, remove this for better cleaning, shaping, filing, and obturation
  • Factors affecting root canal morphology: Trauma - Open Apex
  • Factors affecting root canal morphology: Developmental anomalies - Dens evaginatus, Dilaceration, Taurodontism, Radix Entomolaris, Radix Paramolaris
  • Number of canals in maxillary teeth
    • 11/21: 100% - 1
    • 12/22 (curved distally or distopalatally): 100% - 1
    • 13/23: 100% - 1
    • 14/24: 90% - 2 canals (buccal and palatal), 10% - 1
    • 15/25: 53% - 1, 47% - 2
    • 16/26: 60% - 4 (DB, MB1, MB2, P), 40% - 3 (DB, MB, P)
    • 17/27: 62% - 3, 38% - 4
  • Number of canals in mandibular teeth
    • 31/41: 70% - 1, 30% - 2 (facial and lingual)
    • 32/42: 55% - 1, 45% - 2
  • Number of canals in mandibular teeth
    • 31/41: 70% - 1, 30% - 2 (facial and lingual)
    • 32/42: 55% - 1, 45% - 2
    • 33/43: 70% - 1, 30% - 2
    • 34/44: 70% - 1, 30% - 2
    • 35/45: 85% - 1, 15% - 2
    • 36/46: 70% - 3 (MB, ML, D), 30% - 4 (MB, ML, DB, DL)
    • 37/47: 75% - 3 (MB, ML, D), 25% - 2 (M, D)
  • The lateral has a higher chance of having 2 canals than central
  • The 2nd canal is usually lingual to the main canal
  • The first premolar has a higher chance of having 2 canals
  • Access cavity preparation by Katrina Joyce Tolentino-Flores, DMD, MaEd at UPHS – Binan, Laguna, College of Dentistry
  • Access preparation
    1. Cavity prepared on the crown of the tooth for the endodontic instruments and materials to gain direct path to the apex for biomechanical preparation and obturation
    2. Rationale: A correctly prepared access allows complete irrigation, shaping and cleaning & quality obturation