ETC Exercise 1 Flashcards
Acc to Barrington 2015, What is clearing?
Histological term
Process in which a specimen (or portion is rendered transparent)
According to Barrington 2015 What is Diaphonization?
Clearing an entire specimen or even an animal
Acc to Barrington 2015, How did previous methods used by vertucci of clearing work?
- Required an injection site to be made
- teeth cleaned in soon
- teeth decalcified in Nitri acid
- dehydrated in alcohol
- immersed in methyl salicylate
Acc to Barrington 2015, were the problems with prev methods of clearing?
- required an access to be gained and this could alter the internal structure
- the amount of internal structure revealed was dependant upon the amount of pressure used in the injection process
- Dye access depends on cleanliness of the canal content
- messy and time consuming
Barrington 2015 How must the teeth be stored prior to clearing with the new method?
- Must be extracted and dried within 24 hours of XLA
- no bleach advised
- any blood or PDL remnants left to dry on the outside
What acid and percentage was best used in the new method of clearing teeth Barrington 2015?
HCL 5-7%
Broadly speaking what are the stages of the new method by Barrington?
- Tooth collection
- Dried for 42 hours
- Decalcified in acid
- Dehydration: Immerse teeth in silica/cat litter
- immerse in oil for clearing
- Storage
What is the refractive index?
A measure of how fast light travels through the material
Why isn’t alcohol used in the new Barrington method?
- Alccohol can breakdown or destroy pulp remnants
- Not using alcohol allows air to replace any voids
- The drying method is a lot quicker without alcohol
What is the benefit to the level of detail seen in the new method in Barrington 2015?
- Microanatomy more easily seen from apical regions through to pulp space
- 3D visualisation better than that form CT scan
According to Robertson and Leeb 1982, What is the benefit of clearing teeth?
Allows you to see the microvasculature and canal morphology
What was the aim of Robertson and Leeb 1982 study?
to assess quality of obturation methods
According to Vertucci 2005, what are the diagnostic measures we have to identify number of canals present?
- pre op radiograph
- use of a sharp probe explore on pulp floor
- troughing of grooves
- staining of the pulp floor eg methylene blue
- Visualise canal bleeding points
- Microscope (can increase MB from 51% without scope to 82%)
According to Vertucci 2005 with no magnification use what percentage of MB2 are found?
18.2% Burley et al
According to Vertucci 2005 what is the pulp cavity comprised of?
Pulp chamber + root canal
Where is the pulp chamber located?
Within in the anatomic crown
According to Vertucci 2005 roughly what distance from root apex does apical foramen lie?
0-3mm
What direction do almost all root canals curve?
buccal lingual
According to Vertucci 2005, what is a lateral canal?
an accessory canal located in the coronal or middle third of root
According to Vertucci 2005, what part of the root canal do you see lateral canals?
Most commonly in apical third and lest cervically
According to Vertucci 2005, how are lateral canals formed?
By entrapment of periodontal vessels in HERS during calcification
What is the function of lateral canal?
To allow passage of irritants to the periodontal tissues
According to Vertucci 2005, how do furcal canals form?
Entrapment of periodontal vessels during fusion of diaphragm which forms floor of pulp chamber
According to Verticcu 2005 where are lateral canals most commonly located in mandib molars?
13% furcal
23% coronally
80% from distal root
Which teeth have a greater incidence of furcal canals: max or mandib molars?
Mandib
According to Krasner and Rankow what is the most important anatomy in determining canal morphology?
CEJ in determining location of pulp chambers and root canal orifice
What are the 2 laws of symmetry in helping locating calcified canals as proposed by Krasner and Rankow?
Law of sym 1: except for max molars-orifices are equidistant from line drawn in mesiodistal direction
Law of sym 2: except for max molars: orifices are perpendicular to line drawn in Mesio distal direction across centre of pulp floor
What is the law of colour change helping locating calcified canals as proposed by Krasner and Rankow?
colour of pulp chamber floor is always darker than walls
What are the law of orifice locations helping locating calcified canals as proposed by Krasner and Rankow?
law 1: orifices located at junction between floor and wall
Law 2: located in the angles between floor and wall
Law 3: located at the terminus of rot development fusion lines
What is one type of root canal configuration seen in many molars that mean they don’t comply with laws as proposed by Krasner and Rankow?
c shaped canals
approx 5% of lower 6’s and 7’s
Dentine increases or decreased with age?
Increase
Where does most dentine deposition occur within the pulp?
roof and floor
less on walls
If the canal is in the centre of the root how many canals should be present?
one
What things can aid calcified canal location?
Use of chelating agents Dental dam Magnification Illumination Taking additional radiographs
What feature of canal orifice location would indicate canals joining?
Orifices that are located close to each other
If you place a file into a canal and it points in a buccal or lingua direction what could this indicate?
Second canal present
What happens if you prepare both canals that are joining both to the apex?
Over prep-hour glass shape
If one canal separates into two is this usually MD or BL?
BL
According to Slowey et al What letter can be used to visualise a canal splitting into two?
the letter h
Buccal is the longer part and lingual is the right angledneed to ensure you open up lingually to allow for good access
If there are MB2 canals where can these be located?
either on same line between MB1 and P or slightly mesial and then within 3.5 mm of palatal orifice
Where can the middle mesial root be found? Vertucci 2005
Between the groove of the MB and ML canals see in up to 15%
According to vertuccli 2005 wwhich test most commonly present with c shaped canals?
Lowers 7’s > lower 6’s? upper 6’s and finally upper 4’s
According to Vertucci what is the configuration of the c shaped canals?
more commonly c shaped which divides into separate canals below the c shaped
less commonly c shaped from orifice to apex
In what ethnitcy are c shaped canals more commonly seen in?
Asians
According to verticcu how far is the AC from the AF ?
0.5-1.5mm
Shorter in younger people
Which part of the canal system has the smallest diameter?
AC
At what point does pulp tissue become PDL tissue?
At the CDJ
On average how far is the CDJ from the AF?
1.0mm
What is the minor diameter?
AC
What distance is the AF from the anatomic apex?
0.5-3.0mm
17-46% of cases can be at anatomic apex
What is the most common shape for AC?
Oval
What is the minimum thickness for root dentine thickness after prep?
0.3mm
For ovoid canals which distance is bigger BL or MD?
BL is wider which could leave up to 65% unimstrumented
According to cambruzzi and Masrhall what is an isthmus?
Narrow ribbon shaped communication between two canals containing pulp or pulp ally derived tissue and can also function as a bacterial resevoir
Which teeth have the highest incidence of isthmi?
Upper 6’s with Mb1 and Mb2
usually found within 3-4mm of apex
According to De Deus 1975 what is the most common canal ramification?
Apical delta
According to De Deus 1975 where are lateral canals found?
main canal to PDL from the base of root
According to De Deus 1975 what angle do lateral canals leave at?
slight apical inclination sometimes perpendicular
What are the three areas of the root?
The base
The body
The apex
Where is a secondary canal found?
in the apical region
Where are accessory canals found?
From secondary canals
How was the De Deus study carried out?
- 1140 human molars
- accessed and removal of organic tissue
- prepared and stained
- studied in a viewing box
What were the overall findings of De Deus 1975?
- 27% of teeth showed ramifications
- premolars and molars showed greatest ramifications
- incisors shoed least
- most commonly found in apical region
