Endo Pt 2 Flashcards
Describe K files
Twisted square or triangular metal blanks along their axis; partially horizontal cutting blades
Can be used with the watch winding or balanced force techniques
Describe hedstrom files
Spiraling flutes cut into the shaft of round, tapered, stainless steel wire; very positive rake angle
Cut in only one direction - retraction
Describe barbed broaches
Sharp, coronally angulated barbs in metal wire blanks
Used to remove vital pulp from root canals, sever pulp at constriction level, and remove materials from canals.
Describe nickel-titanium rotary instruments
Designs vary in tip sizing, taper, cross section, helix angle, and pitch.
Important properties - superelasticity and high resistance to cyclic fatigue, which allows continuously rotating instruments to be used in curved root canals.
Nickel-titanium instruments have reduced incidence of blocks, ledges, transportation, and perforation but are believed to fracture more easily than hand instruments
Endosequence, lightspeed, proFile, proTaper
Describe how to determine working length
Select a point that is table and easily visualized for reference point selection.
Estimate working length with diagnostic film taken using a paralleling technique with a no. 10 or 15 K-file.
If necessary, correct the working length by measuring the discrepancy between the radiographic apex and tip of file . Adjust to 1mm short of radiographic apex
Use an apex locater - an electronic instrument used to assist in determining the root canal working length or perforation; operates on the principles of resistance, frequency, or impedance
Feel for the apical constriction, however in many cases this can be unreliable
The best indicator of clean walls is the ____. It shaping, it is best to __ ___ files because essentially all canals are curved.
Smoothness obtained
Precurve inflexible
____ of canal permits debridement of apical canal, reduces overinstrumentation of the foramen, and improves ability to obdurate
Taper
Name and describe 3 different techniques for cleaning and shaping.
Crown-down: clinician passively inserts a large instrument into the canal up to a depth that allows easy progress. The next smaller instrument is used to progress deeper into the canal; the third instrument follows, this continues until the apex is reached. Hand and rotary instruments may be used in this technique.
Step-back: working lengths decrease in a stepwise manner with increasing instrument size.
Hybrid technique - combining these two techniques to achieve the best outcome
Describe how to do the apical preparation
Apical stop helps confine instruments, materials, and chemicals to the canal space and create a barrier against which gutta-percha can be condensed.
What is a D1 file dimension?
File size at the tip of the file (.08mm for a size 8 file. 0.15mm for a size 15 file size)
What is the D2 or D16 file dimension?
The diameter of the file where the cutting flutes end (16mm)
It is the diameter at the tip plus 0.32mm (if the taper was 0.02)
True or false… sodium hypochlorite dissolves organic material and removes the smear layer.
False. It does dissolve organic matter (its a proteolytic material) but it does not remove the smear layer)
What are the signs and symptoms of a NaOCl accident?
Instant extreme pain
Excessive bleeding from teh tooth
Rapid swelling
Rapid spread of erythema
Later-bruising and sensory and motor nerve deficits
What are treatment options for a NaOCl accident?
Long-lasting local anesthetic
Encourage drainage
Steroids
Cold compresses
Antibiotics
Analgesics
Daily follow-up
What is EDTA?
Ethylenediamine tetraacetic acid
What does EDTA do?
Removes inorganic material
Removes smear layer
Chlorhexidine is a _____ and ___ molecule that interacts with ___ and ___ on the ___ of bacteria and enters the cell by changing ____ equilibrium and is effective at the concentration of __%
Synthetic cationic hydrophobic and lipophilic
Phospholipids and lipopolysaccharides on the cell membrane
Osmotic
2%
The combination of __ and ___ forms an undesirable precipitate, ___, which is believed to affect the seal of root canal filling.
Chlorhexidine
NaOCl
Parachloroaniline
What is the best intracanal medicament available?
Calcium hydroxide
Calcium hydroxide’s high pH causes an antibacterial effect at pH of ___. It inactivated ____. It has a ___ capacity.
12.5
Lipopolysaccharides
Tissue-dissolving
What are the purposes of obturation?
To eliminate all avenues of leakage from the oral cavity or the apical tissues into the root canal system
To seal within the system any irritants that cannot be fully removed during canal cleaning and shaping procedures
What are 5 advantages of gutta-percha?
Plasticity - adapts with compaction to irregularities
Easy to manage
Little toxicity
Easy to remove
Self-sterilizing (does not support bacterial growth)
What are 4 disadvantages of gutta percha?
Gutta-percha without sealer does not seal
Lack of adhesion to dentin
Elasticity causes rebound to dentin
Shrinkage after cooling
The best treatment for swelling from acute apical abscess is to _____
Establish drainage and to clean and shape the canal
What are three indications for incision and drainage of soft tissues?
If a pathway is needed in soft tissue with localized fluctuation swelling that can provide necessary drainage
When pain is caused by accumulation of exudates in tissues
When necessary to obtain samples for bacteriological analysis
What are three indications for trephination of hard tissues?
If a pathway is need from hard tissue to obtain necessary drainage
When pain is caused by accumulation of exudate within the alveolar bone
To obtain samples fro bacteriological analysis
What is trephination?
Refers to surgical perforation of the alveolar cortical bone to release accumulated tissue exudates
Why is profound anesthesia difficult to achieve for I and D or trephination procedures?
The acidic pH of the abscess and hyperalgesia
How deep should the incision be made for an I and D procedure?
Made firmly through periosteum to bone
Vertical incisions are parallel with major blood vessels and nerves and leave very little scarring
These procedures may include the placement and subsequent timely removal of a drain
Antibiotics may be indicated in which cases?
Patients with diffuse swelling (cellulitis)
Patients with systemic symptoms
Patients who are immunocompromised
When is root end resection (apical surgery/apicoectomy) indicated?
Persistent or enlarging apical pathosis after nonsurgical endodontic treatment
Nonsurgical endodontics is not feasible
Marked overextension of obturating materials interfering with healing
Biopsy is necessary
Access for root-end preparation and root-end filling is necessary
The apical portion of the root canal system with apical pathosis cannot be cleaned, shaped, and obturated
What are 4 contraindications to root-end resection?
Anatomic factors - thick external oblique ridge or proximity to the neurovascular bundle
Medical or systemic complications
Nonrestorability
Poor root/crown ratio
What is the procedure for root end resection?
Root end resection is the preparation of a flat surface by the excision of the apical portion of the root and any subsequent removal of attached soft tissues
Lay flap
Bone is removed to allow direct visualization of and access to the affected area
Root end is respected
Root end is filled.
What are 3 disadvantages to a submarginal curved flap (semilunar flap) for a root end resection procedure?
Restricted access with limited visibility
Leaving the incision directly over the lesion
Often healing with scarring
In root end resection, resection of __mm of diseased root tip is performed. The traditional __-degree bevel has been replaced with a lesser bevel of 0-10 degrees.
3mm
45
In root end resection, __mm should be left for root end cavity preparation and root end filling. Prepare __mm of the root end with ultrasonic instrumentation. __ the depth of the root end filling significantly decreases apical leakage. Increasing the bevel ___ leakage.
3mm
3mm
Increasing
Increases
In root end filling (retrofilling), a biologically acceptable filling material, such as ___ is placed into the ___ root end preparation to seal the root canal system.
MTA (mineral trioxide aggregate)
3mm
What is root hemisection?
Surgical division (in approximately equal halves) of a multirooted tooth. A vertical cut is made through the crown into the furcation. The defective half of the tooth is extracted.
What are the indications of hemisection?
Class3 or 4 periodontal furcation defect
Infrabony defect of one root of a multirooted tooth that cannot be successfully treated periodontally
Coronal fracture extending into the furcation
Vertical root fracture confined to the root to be separated and removed
Carious, resorptive root or perforation defects that are inoperable or cannot be corrected without root removal
Persistent apical pathosis in which nonsurgical treatment or apical surgery is impossible and the problem is confined to one root.
Hemisection is most often performed on ___ teeth. Hemisection requires root canal treatment on all retained ___. When possible, it is preferable to complete the root canal treatment and place a permanent restoration into the canal orifices [before/after] the hemisection.
Mandibular molar
Root segments
Before
What is bicuspidization?
A surgical division (as in hemisection, usually a mandibular molar), but the crown and root of both halves are retained.
The procedure results in complete separation of the roots and creation of two separate crowns.
What is the difference between root end resection and root resection?
Root end resection is amputating just the tip of a root whereas root resection is complete removal of one or more roots of a multirooted tooth (root amputation)
What are 7 indications for root resection (root amputation)?
Class 3 or 4 periodontal furcation defect
Infrabony defect of one root of a multirooted tooth that cannot be successfully treated periodontally
Existing fixed prosthesis
Vertical root fracture confined to the root to be resected
Carious, resorptive root or perforation defects that are inoperable or cannot be corrected without root removal
Persistent apical pathosis in which nonsurgical root canal treatment or apical surgery is impossible
At least one root is structurally sound
In root resection, amputation of an entire root is performed leaving the crown in tact. Root resection requires ___ on all ___. When possible, it is preferable to complete root canal treatment and place a permanent restoration into the canal orifices.
Root canal treatment
Retained root segments
What is intentional reimplantation?
Insertion of a tooth into its alveolus after the tooth has been extracted for the purpose of accomplishing a root end filling procedure.
True or false… in intentional reimplantation stabilization of the reimplanted tooth is always needed.
False. It may or may not be needed.
True or false… RCT is typically performed before intentional reimplantation
True
What are 5 indications of intentional reimplantation?
Persistent apical pathosis after endodontic treatment
Nonsurgical retreatment is impossible or has an unfavorable prognosis
Apical surgery is impossible or involves a high degree of risk to anatomic structures
The tooth presents a reasonable opportunity for removal without fracture
The tooth has an acceptable periodontal status before the reimplantation procedure
When is surgical removal of the apical segment of a fractured root indicated?
When a root fracture occurs in the apical portion and pulpal necrosis results
In surgical removal of the apical segment of a fractured root, a ___ flap is surgically elevated, and when necessary ___ is removed to allow direct visualization and acces to the affected site. The __ portion of the affected root and all of the targeted tissue are removed.
Mucoperiosteal
Bone
Apical
Endodontic emergencies are usually associated with __ or __ or both and require immediate __ and ___
Pain or swelling
Diagnosis and treatment
Emergencies are usually caused by pathoses in the __ or ___ tissues. Emergencies include ___, ___or __
Pulp or periapical
Luxation, alvulsion, or fractures of the hard tissues
Radiographic examination of emergency cases are helpful but has limitations because…
Periapical radiolucencies may not be present in acute periapical periodontitis
What is the preferred treatment for management of painful irreversible pulpitis?
Complete cleaning and shaping of the root canals
Pulpectomy provides the greatest pain relief but pulpotomy is usually effective in the absence of percussion sensitivity
True or false.. chemical medicaments sealed in chambers do not help control or prevent addional pain in painful irreversible pulpitis
True
True or false… antibiotics are indicated in painful irreversible pulpitis
False.
When localized swelling exists, the abscess has invaded ___. Compete debridement should be performed as well as ___ to relieve pressure and purulence. Patients with localized swelling [often/seldom] have elevated temperatures or systemic signs, so systemic antibiotics are [unnecessary/necessary]
Soft tissues
Drainage
Seldom
Unnecessary
When diffuse swelling exists, the swelling has dissected into ___ spaces. Most important is the removal of the irritant via __ or ___. Swelling may be incised and drained followed by ___ insertion. Systemic antibiotics are [indicated/contraindicated] for diffuse, rapid swelling.
Fascial
Canal debridement or extraction
Drain
Indicated
A history of preoperative pain or swelling is the best predictor of ___ emergencies
Flare-up
