ENDO Basic Endodontic Treatment Procedures Flashcards
what are the 4 objectives of nonsurgical endodontics?
- to alleviate and prevent future adverse clinical symptoms
- to debride and shape the root canal
- to create the radiographic appearance of a well-obturated root canal system where the root canal filling extends as close as possible to the apical constriction
- the maintain health and/or promote healing and repair of periradicular tissues
what is the most important phase of the technical aspects of root canal treatment?
access preparation
proper access preparation maximizes what 3 things?
cleaning, shaping, and obturation
what are the 3 objectives of access preparation?
straight-line access, conservation of tooth structure, and unroofing of the chamber to expose orifices and pulp horns
straight line access requires adequate tooth structure removal and improves what aspects of access preparation?
- improved instrument control, with less zipping, transportation, or ledging
- improved obturation
- decreased procedural errors, such as ledges or perforations
how does conservation of tooth structure improve RCT outcomes?
minimal weakening of the tooth and prevention of accidents
how does unroofing the chamber to expose orifices and pulp horns aid in access preparation?
- maximum visibility
- prerequisite in locating orifices of canals
- improved straight line access
- exposure of pulp horns
what are the techniques for determining working length?
- estimate WL with a diagnostic film taken using a paralleling technique with a #10 or 15 k file
- correct WL by measuring the discrepancy between the radiographic apex and tip of file; adjust to 1mm short of radiographic apex
- use apex locator (operates on the principles of resistance, frequency, or impedance)
- tactile sensation (often unreliable)
what is the best indicator of clean walls?
level of smoothness obtained
taper of the canal permits what 3 things?
debridement of apical canal, reduces overinstrumentation of the foramen, and improves ability to obturate
what are the 3 cleaning and shaping techniques?
- crown-down
- step-back
- hybrid
which cleaning and shaping technique involves the clinician passively inserting 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, and the third instrument follows. this continues until the apex is reached. hand and rotary instruments may be used in this technique
crown down
which cleaning and shaping technique involves working lengths that decrease in a stepwise manner with increasing instrument size
step back
which cleaning and shaping technique involves the combination of crown down and step back?
hybrid
___ help confine instruments, materials, and chemicals to the canal space and create a barrier against which gutta percha can be condensed
apical stops
what denotes the file size at the tip of the file?
D1 (ex. 0.08mm for a size 8 file, 0.15mm for a size 15 file)
what denotes the diameter of the file where the cutting flutes end?
- D2 or D16 (flutes end at 16mm)
- it is the diameter at the tip plus 0.32mm (ex. for a 0.02 taper #8 file, it is 0.08mm + (16mm x 0.02mm) = 0.40mm)
what is sodium hypochlorite used for in endodontics?
- irrigation
- disinfection of root canals - hypochlorite anion
- dissolving organic matter - proteolytic material
does sodium hypochlorite remove the smear layer?
no
concentrations of sodium hypochlorite vary from ___ to ___
0.5% to 6%
what are the signs and symptoms of a sodium hypochlorite accident?
- instant extreme pain
- excessive bleeding from the tooth
- rapid swelling
- rapid spread of erythema
- later - bruising and sensory and motor nerve deficits
what is the treatment for a sodium hypochlorite accident?
- long lasting local anesthetic
- encourage drainage
- steroids
- cold compresses
- antibiotics
- analgesics
- daily follow up
what does EDTA stand for?
- ethylenediamine tetraacetic acid
- contains 17% EDTA
what are the indications for EDTA?
- irrigation
- removes inorganic material
- removes smear layer
___ is a synthetic cationic hydrophobic and lipophilic molecule
chlorhexidine
what is the mode of action of chlorhexidine?
interacts with phospholipids and lipopolysaccharides on the cell membrane of bacteria and enters the cell by changing osmotic equilibrium
chlorhexidine is effective at what concentration?
2%
the combination and chlorhexidine and ___ forms an undesirable precipitate, parachloroaniline, which is believed to affect the seal of root canal filling
sodium hypochlorite
___ is the best intracanal medicament available
calcium hydroxide
which characteristic of calcium hydroxide causes an antibacterial effect?
its high pH (12.5)
calcium hydroxide inactivates ___ and has ___ capacity
inactivates lipopolysaccharides and has tissue-dissolving capacity
what are the main 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 the 5 advantages of gutta percha?
- plasticity
- easy to manage
- little toxicity
- easy to remove
- self-sterilizing (does not support bacterial growth)
what are the 4 disadvantages of gutta percha?
- gutta percha without sealer does not seal well
- lack of adhesion to dentin
- elasticity causes rebound to dentin
- shrinkage after cooling
___ is a surgical perforation of the alveolar cortical bone to release accumulated tissue exudates
trephination
what are the objectives of incision and drainage?
evacuate exudates and purulence and toxic irritants
removal of pus during incision and drainage procedures speeds ___ and reduces ___
speeds healing and reduces discomfort from irritants and pressure
what is the best treatment for swelling from acute apical abscess?
establish drainage and to clean and shape the canal
what are the 3 indications for incision and drainage?
- if a pathway is needed in soft tissue with localized fluctuant swelling that can provide necessary drainage
- when pain is caused by accumulation of exudates in tissues
- when necessary to obtain samples for bacteriologic analysis
what are the 3 indications for trephination of hard tissues?
- if a pathway is needed from hard tissue to obtain necessary drainage
- when pain is caused by accumulation of exudate within alveolar bone
- to obtain samples for bacteriologic analysis
___ is a surgical opening created in soft tissue for the purpose of releasing exudates or decompressing an area of swelling
incision and drainage
why is it difficult to achieve profound anesthesia in the presence of an infection?
because of the acidic pH of the abscess and hyperalgesia (increased sensitivity to pain)
when performing an incision and drainage procedure, the incision should be made firmly through ___ to ___
periosteum to bone
when performing an incision and drainage procedure, vertical incisions are typically made because ___
they are parallel with major blood vessels and nerves and leave very little scarring
incision and drainage and trephination procedures may include the placement and subsequent timely removal of a ___
drain
when are antibiotics indicated after incision and drainage and trephination procedures?
in patients with diffuse swelling (cellulitis), patients with systemic symptoms, or patients who are immunocompromised
what are the indication for root end resection (apical surgery or apicoectomy)?
- persistent or enlarging apical pathosis after nonsurgical endodontic treatment
- nonsurgical endodontics is not feasible
in what cases is nonsurgical endodontics not feasible and thus root end resection is indicated?
- 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 the contraindications for root end resection?
- anatomic factors such as a thick external oblique ridge or proximity of the neurovascular bundle
- medical or systemic complications
- nonrestorability
- poor root/crown ratio
___ 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
root end resection (apical surgery or apicoectomy)
what are the basic steps for the root end resection procedure?
- cut/elevate mucoperiosteal flap and remove bone if necessary
- root end resection
- root end filling (retrofilling)
- primary closure of surgical site
what are the common flap designs used for root end resection?
- submarginal curved flap (semilunar flap)
- submarginal triangular and rectangular flaps
- full mucoperiosteal flap
what are the disadvantages of the submarginal curved flap (semilunar flap) in relation to root end resection?
- restricted access with limited visibility
- leaving the incision directly over the lesion
- often healing with scarring
during root end resection, how many mm of the diseased root tip should be removed, and at what degree bevel?
3mm of disease root tip is removed at a 0-10 degree bevel (as opposed to the traditional 45 degree bevel)
during root end resection, ___mm of the root end should be left for cavity preparation and root end filling
3mm
during root end resection, how is the root end cavity prepared?
with ultrasonic instrumentation