Endodontics Quiz: Tooth Roots and Canals

Endodontics

Root Anatomy

• Maxillary first molar usually has three roots
• Mandibular molar usually has two roots
• MB root of maxillary first molar has two canals 58% of the time
• Maxillary first premolar usually has two canals
• Mandibular molar usually has two or three canals

Endodontic Treatment

• Endodontic treatment of mandibular central incisor can be challenging due to two canals
• Endodontic access on mandibular incisors is most challenging due to narrow mesio-distal dimension, making it easy to perforate

Endodontic Files and Materials

• Endodontic files, gutta percha, and sized paper points are color coded
• Size 10 file is white, size 35 file is green, size 70 file is blue, size 25 file is red

Working Length Determination

• Estimated working length (WL) is determined using a radiograph
• If the file is out of the canal by 1 mm, adjust the file size or length to achieve accurate WL

File Selection and Usage

• Initial apical file should be slightly tight in the canal
• Master Apical File (MAF) is 3 sizes bigger than the initial file
• In curved canals, pre-curving files is not necessary
• When using a size 15 file, the MAF would be size 40

Signs and Symptoms of Endodontic Pathosis

• Acute apical periodontitis symptoms: tooth tenderness to percussion, tooth feels extruded, PDL space may be normal or widened
• Acute alveolar abscess is a dental emergency, treatment involves establishing drainage via the root canal, incision for additional drainage, prescribing antibiotics and analgesics, and disoccluding the tooth if extruded

Medical Considerations

• Radiation therapy to the head and neck can result in increased sensitivity of teeth and mimic dental pain
• Certain medical conditions, such as sickle cell anemia, trigeminal neuralgia, referred pain from cardiac angina, and multiple sclerosis, can mimic odontogenic pain
• Precautions for treating hypertensive patients: consult with physician, slow injection of local anesthesia, and terminate the appointment if patient becomes stressed

Case Selection and Radiographic Analysis

• Factors to consider in case selection: clinician considerations, patient considerations, and tooth considerations
• A radiograph is a 2-dimensional representation of a 3-dimensional object, providing incomplete information about the tooth

Pain Relief and Pulpectomy

• Intracanal pressure in irreversible pulpitis or necrotic cases causes pain, relief methods include pulpotomy/pulpectomy, establishing length control, instrumentation, and debridement
• Is it extremely important to take the tooth out of occlusion when the patient says the tooth feels elevated/painful when closing their mouth?

Sodium Hypochlorite and EDTA

• Sodium hypochlorite (NaOCl) plays a crucial role in endodontic treatment
• EDTA (ethylenediaminetetraacetic acid) removes the smear layer, helps enlarge narrow canals, and lubricates
• EDTA is a chelating agent, but not effective as the sole irrigant during instrumentation
• Mixed irrigants should be avoided, especially repeated cycling of sodium hypochlorite and EDTA

Obturation

• The main purpose of the root canal sealer is to fill canal irregularities and minor discrepancies between root canal walls and core filling material
• Gutta percha gets brittle with age, difficult to introduce into a narrow canal, and lacks adhesion to dentin
• Do not want the sealer to fill accessory canals, but it can act as a lubricant during insertion of the master cone

Miscellaneous

• Schilder's Mechanical Objectives during cleaning and shaping root canals include continuous taper from crown to apex, cross section should widen at every point going apically, preparation should follow the canal, apical foramen should be maintained, and the apex should be kept as small as possible
• Establishing the glide path is not the same as determining canal patency
• Coronal pre-enlargement involves enlarging the coronal third of the root canal prior to working length determination