Endo Flashcards
What are the four principle to endo ?
- Respect the integrity of the pulp and the periodontal tissues by avoiding mechanics, and chemical trauma
- Protect vital pulp
- Provide RCT tho eliminate any source of infection
- Follow up
What is endo?
Branch of dentistry that deals with the aetiology diagnosis prevention and management of diseases of the dental pulp and their sequelae
What are the stages to endo?
Diagnosis Access Canal prep Canal medicaments Obturation Follow up
What type of bacteria cause endo lesions?
Aerobic and anaerobic but becomes more anaerobic with time and more gram negative
What type of relationship exist between the bacteria?
Symbiotic
Name the bacteria involved in endo?
Streptococci
Prevotella oralis
Porphyromonas
How do Bactria gain access to the root?
Deep carious lesion
Anchoresis
Perio
Trauma
What is the mantra for endo?
Cleans
Shape
Obturate
What is the aim of endo?
Provide a 3D hermitic apical and coronal seal
What lesion may we see adjacent to the tooth to indicate pulp deAth?
Sinus
What must we take before beginning endo?
Medical dental and social history
Full pain diagnosis
X-ray
What must you look at on the pre op X-ray?
- Large restoration or caries, previous pulp cap,
- pupal reaction, narrow canals, chamber, internal resorption
Pulp chamber: position of roof and floor and how much reparative dentine
Root canals: number of roots and canals, how much calcification, pulp,stones? And canal curvature
Any previous root filling, Periapical radiolucency
What is the apical war zone?
PMN
Macrophages
B and T cells
Plasma cells
What are the inflam mediators involved?
CLN
Complement
Lysozymes
Neuropeptides
What is the perical lesions caused by?
PLC
Prostaglandins
Leukotrienes
Cytokines
What must you assess with regards to the tooth that you are going to Do RCT on?
Look: Colour Caries Presence of sinus Erythema over apex
Touch:
Mobility
TTP
Tender to palpation
Invasive :
Vitality
Local perio
Radiograph to show pulp morphology
What is the first stage of endo once the assememt has been done? And what can you use for this?
Access
High speed burs for initial access and them slow speed eg tapered fissure/endo Z/Blunt ended/ or round burs
What is special about some of the ways the access burs are made?
They have long shanks and some have blunt ends (non cutting tip)
What is the diagnosis for the pulp following investigations?
Healthy
Reversible pulpitis
Irreversible pulpitis
Necrotic pulp
What are the requirements of the pre op radiograph?
Treatment tooth centrally located with at least 3-4mm peri Radicular tissue available and taken with film holder to minimise distortion
Second film taken at 15/20 degrees horizontal parallax
What is the purpose of the access cavity?
Removes the entire roof of pulp
Allows debridement
Allows access to the canals with straight line
Allows placement of temporary cement between visits
Conserved tooth structure but still achieve goal s
What shape should the access cavity be?
Non undercut
What is the shape of the access cavity determined by?
Position and number of pulp horns
How manu pulp horns does an incisor have?
3
How many pulp norms does a canine have?
2
How Many pulp horns does a premolar have?
2
Ovoid
What shale is the access cavity for molars?
Triangular
What size magnification does an operating microscope use?
X16
What size magnification do loupes provide?
X2 to 4.5
What can be used to locate canals?
Knowledge of anatomy Information from radiographs Magnification technqiue Trans illumination with white light Canal probe Fine endo instruments eg 6,8 Dyes Ultrasonic
What access problems may you come across?
Crown in situ so loss of directional sense
Obstruction within canal eg pulp stones, post crown, fractured instrument
How do you acces?
- Check depth from reference point to roof of pulp chamber
- Use tapered fissure bur to create outline in dentine
- Continue in depth until pulp chamber reached
- Apply rubber dam
- Remove roof of pulp using slow speed long shank bur Refine the cavity and cut on the out stroke to flare access
- Clear debris from chamber with excavators
- Irrigate with sodium hypochlorite
- Locate orifices if canal and check straight line access
What is the advantage of rubber dam?
Protects oro pharynx
Protects soft tissue From caustic material
Retracts soft tissue and tongue and improved access
Maintains clean dry and aseptic working environment
What is the next stage following access?
Measure the working length
How can working lengths be measured?
Tables of average length
Apex locator
Radiographs
What is the average length for the maxillary incisors and premolars from average value tables? What is the disadvantage of this?
Central: 23.70 Lateral: 22.10 Canine: 27.30 Four: 22.30 Five: 22.30
Dis: makes huge assumptions
How does an apex locator work?
Measure electrical resistance between an instrument in a root and an electrode attached to the oral mucosa
It passes a direct current through the tissue
What is the average value of the resistance at the apical tissus?
6.5kohms
How acurste are apec locates?
90%
What are the problems with apex locators?
Dentine debris can deflect from accuracy
Avoid use on wide canals and open apices
Remove excess fluid
Wet canals: absolutely ALmmachines only from pus, exudate, hyochlorote
Heavily restored teeth: all machines
Poor contact of lip electrode
What is the radiographic working length?
Measurement from fixed reference point kncisallt or occlusals to the radiographic Apex of the root minus 1mm
What is the working length?
Distance from a fixed reference point on the crown of a tooth to the terminus near the radiographic apex
What is the terminus?
Point where tooth naturally constricts where secondary cementum invaginates
Once you have got your working length what must you check?
Canal patency
How can we open the orifice of the canal?
Hedstrom
Gates glidden
SX protaper fils
How are Hedstrom files made?
They are machines from a round blank by cutting a spiral groove along the shank. This creates a sharp cutting blade to produce a file with an aggressive cutting action