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Access Cavity

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110 views91 pages

Access Cavity

Uploaded by

dentist727
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
You are on page 1/ 91

Before

drilling…

1
Endodontic  Treatment  
needs  Local  Anesthesia

2
Patients  do  not  know  how  
well  you  clean  ,  shape  and  
obturate  their  root  canals  
but  they  do  know  if  you  
hurt  them.
3
“ Nothing kills a great
endodontic procedure
like a patient who is not
numb ”
Richard Mounce: Endodontics:Excellence,Speed ,Profitability,
Dental Economics, Oct., 2003
4
Re-­‐test  using  patient’s  
chief  complaint

5
If  anesthesia  doesn’t  
work…..

6
-­‐                        Inject  again

-­‐                            Higher

–  More  Local  Anesthesia 7


Consider    
Intrapulpal  Anaesthesia

Back-­‐pressure  is  the  key  to  


intrapulpal  anesthesia  
success
8
 If  they  say  it  hurts,  
it  hurts
9
Isolation

10
Rapid Rubber Dam
Placement
(1864)
11
Tooth  isolation  using  the  
dental  dam  is  the  standard  of  
care  

it  is  integral  and  essential  for  


any  endodontic  treatment.  

12
Access  cavity
13
*  Access  preparation  
is  the  key  to  
endodontic  success  
and  to  long-­‐term  
retention  of  the  tooth    
14
 A  perfect  access  will    
save  you  time  on  
everything  else  and  
reduce  the  stress  of  a  
difficult  root  canal  
treatment.   15
   Access  cavity  
stages    
16
   *  Pre-­‐treatment  
assessment    
   
17
   clinicians  must  have  
well-­‐angulated  
radiographic  imaging  of  
the  tooth  to  evaluate…    

18
   *  Preparation  of  the  
Traditional  Access  Cavity

    19
Removal  of  unsupported  
tooth  structure  helps  prevent  
fracture  of  fragile  enamel  
walls  and  possibly  the  entire  
tooth  during  treatment    
    20
remove  all  coronal  pulp  
tissue  (vital  or  necrotic)  

21
the  access  cavity  must  be  
wide  enough  to  permit  the  
endodontic  instruments  
unhindered  entry
ARNALDO  CASTELLUCCI  
22
Access  cavity  should  Provide  
straight  or  direct  access  to  the  
initial  curvature  of  the  canal.  

ARNALDO  CASTELLUCCI  
23
facilitate  the  introduction  of  
canal  instruments  into  the  root  
canal  opening  which  reduce  time  
and    the  stress  of  a  difficult  root  
canal  treatment  

24
X

25
Flaring the internal axial
walls in a brushing
manner on the outstroke
to eliminate the dentinal
triangle..
26
* enlarge  each  orifice  
individually  as  it  is  located  and  
before  excavation  is  performed  
to  locate  others.

27
* Disadvantages of
Traditional
Access Cavities

28
*  it  removes  valuable  dentin  

29
This  will  leave  tooth  structure  
compromised  and  less  able  to  
withstand  functional  loads    

30
Conservative
Access Cavities
Modern  Molar  Endodontic  Access  and  
Directed  Dentin  Conservation    
David Clark, John Khademi,Dent Clin N
Am 54 (2010) 249–273 31
*  In  recent  years,  a  shift  has  
been  proposed  to  transform  
the  endodontic  cavity  from  
the  traditional  design  to  one  
that  focuses  on  dentin  
preservation  
32
*  The  long-­‐term  retention  of  
the  tooth  and  resistance  to  
fracturing  are  directly  related  to  
the  amount  of  residual  tooth  
struc  ture. The  more  dentin  we  
 

keep,  the  longer  we  keep  the  


tooth.  
 

* Dr. Vipin Arora, GJRA Volume-4, Issue-7,


,

July-2015 33
*  the  access  cavity  must  never  
be  that  small  so  as  to  inhibit  
visual  detection  of  the  root  
canal  orifices.    
 
 

34
*  On  the  other  hand,  excessive  
preparation  will  reduce  the  
structural  strength  of  the  
remaining  tooth  tissues  and  
hence  the  resistance  to  fracture    
 
 

35
Conservative Endodontic
Cavities
*  The  removal  of  restorative  
materials  before  tooth  structure

*  Enamel  before  dentin  


*  Occlusal  tooth  structure  before  
cervical  dentin. 36
Peri-­‐cervical  Dentin  
*  Preserve  of  the  pericervical  dentin  
(located  4  mm  above  and  below  the  
crestal  bone)  to  the  greatest  extent  
possible  is  very  important

* Clark D, Khademi JA. Dent Clin North Am.


2010;54:275-89. 37
*  It  acts  as  the  neck  of  the  tooth  
and  transfers  masticatory  forces  to  
the  root  and  the  bone.    

*  The  dentin  near  the  alveolar  crest  


is  not  replaceable  and  is  sacred    

   

 
* Dr. Vipin Arora, Peri-Cervical Dentin (PCD)-
GJRA Volume-4, Issue-7, July-2015
,
38
*  The  orifice  openers  and  gates  
glidden  drills  are  the  main  
instruments  responsible  for  the  
loss  of  cervical  dentine.  To  
further  add  on  this  effect  is  the  
use  of  greater  taper  files.    

* Dr. Vipin Arora, GJRA   Volume-4, Issue-7,


,

July-2015 39
The  former  instruments  tend  to  
straighten  the  canal,  weaken  
the  root  walls  and  predisposing  
them  to  cracks  and  in  some  
cases  leads  to  irreparable  
defects,  like  root  wall  stripping  
defects.  

40
* NiTi instrument systems for coronal
canal flaring, were reported to have
lower rates of crack formation than
those found with Gates-Glidden drills

* Arslan H, Karatas E, Capar ID, Ozsu D, Doğanay E (2014) Effect


of ProTaper Universal, Endoflare, Revo-S, HyFlex coronal flaring
instruments, and Gates Glidden drills on crack formation. J Endod
40:1681–1683
*
The  access  cavity  should  be  
considered  subject  to  
modification  at  any  time,  if  the  
need  arises.  

42
-­‐ When  one  or  more  walls  
of  the  access  cavity  are  
missed  because  of  
previous  carious  
destruction…                          
reconstruct  it   43
-­‐ Always  have  four  walls

2
3

1
4
44
When  one  or  more  walls  of  the  
access  cavity  are  missed  because  of  
previous  carious  destruction,  it  or  
they  must  be  reconstructed  to  have  
four  walls  .

45
Access Cavity
Procedure

46
-­‐ Penetration  Phase        
“Go  for  the  pulp  horns”    

47
use of high-speed diamond burs
with concomitant water cooling to
penetrate the enamel and dentin in
the direction of the largest
dimension of the pulp chamber.
- Cut just 1 mm then evaluate
position and direction and correct
any discrepancies before
continuing further toward the pulp
chamber. 48
- Penetrating deeper and deeper
with the same shape until you
penetrate the pulp chamber

49
- Any  permanent  tooth  (not  
worn  down)has  a  pulp  
chamber  that  is  situated  
approximately                                
7  mm                                              
from  a  cusp  tip  or  an  incisal  
edge   50
- think  real  hard  before  
cutting  further  and  stop  
yourself  until  you  know  
where  you  are  going    

51
-­‐ Enlargement  Phase  

52
-­‐  After  entering,  remove  any  
remaining  pulp  chamber  roof  and  
thoroughly  clean  all  of  its  walls,  
being  sure  not  to  touch  the  f loor  
of  the  chamber.  
   
53
 -­‐  The  bur  is  working  on  the  
dentinal  walls  with  a  brushing  
motion.  In  this  way,  all  the  
over  hangings  of  dentin  left  
behind  in  the  preceding  phase  
are  removed  

-­‐  Smooth  the  walls  of  the  access  


cavity 54
Don’t use
burs to
locate
canals!! 55
Anterior  Teeth    

56
* Traditional
Access Cavities

57
For  an  intact  tooth,  cutting  
commences  at  the  center  and  
perpendicular  to  the  lingual  or  palatal  
surface  of  the  anatomic  crown     58
* Conservative
Access Cavities

59
Unnecessarily  cutting  an  
access  preparation  that  
is  up  to    50%  larger  than  
is  necessary.    
 
60
*  a  slot-­‐like  cavity  be  cut  providing  
a  straight  file  path  into  the  canal 61
*  after  which  an  ultrasonic  
device,  or  tapered  diamond  
bur  in  a  high  speed  hand-­‐  
piece  be  used  to  bevel  the  
pulp  chamber  roof  coronal  to  
the  mesial  and  distal  pulp  
horns.  
62
By  minimally  unroofing  these  
pulp  chamber  projections,  
clinicians  can  be  assured  that  
no  pulp  debris  remains  in  
them  
63
Perforations  of  anterior  
teeth  invariably  
penetrate  the  buccal  
root  surface…….  
64
so  when  you  are  five  
millimeters  in,  haven’t  
found  the  chamber,  and  
are  wondering  whether  
you  should  cut  more  to  
the  buccal  or  lingual…..    
65
head  toward  the  
lingual….  
it’s  safer….    
66
Maxillary Molars

67
*  The  palatal  and  disto-­‐buccal  
roots  each  have  one  canal.
Approximately  90%  of  
maxillary  first  molar  teeth  
have  two  canals  (MB1  and  
MB2)  in  the  mesio-­‐  buccal  
root.     68
the  point  of  
entry  is  on  is   MB cusp
on  the  
central  
groove  
halfway  
D X M
between  the  
mesial  and  
distal  
boundaries.    
ML cusp
Loss  of  marginal  ridge  results  in  
46%  loss  of  rigidity    
J Prosthodontics 2008
70
round  burs  cut  very  irregular  
shapes  in  access  walls,  a  result  
that  makes  every  following  part  
of  the  RCT  more  difficult.    
 
71
Straight  small  burs  is  my  favorite  
option     72
* enlarge  each  orifice  
individually  as  it  is  located  and  
before  excavation  is  performed  
to  locate  others.

73
This  technique  will  help  provide  proper  
spatial  and  visual  orientation  of  the  
pulp  chamber  anatomy.

Either  the  location  of  all  canals  will  be  


confirmed,  or  the  orientation  will  act  as  
a  guide  to  the  location  of  the  other  
unidentified  canal  orifices.    
74
If a plug of dentin covers
the orifices that have
been identified.. use
ultasonics and shave
dentine…
Then dense orifice dentin
will be removed or
softened, and small files
can penetrate easily and the
“following” motion can
begin
Mandibular Molars

77
*  The  mesial  root  almost  
always  has  two  mesial  canals

*  Approximately  60%  of  distal  


roots  have  only  one  canal,  and  
the  remaining  40%  have  two  
canals     78
* *Approximately  5%  of  
mandibular  molar  teeth  
have  three  mesial  canals  
* *  The  third  mesial  canal  is  
usually  located  between  the  
mesio-­‐buccal  and  mesio-­‐
lingual  canals     79
Mesial  
boundaries   ML cusp
a  line  
connecting  
the  mesial  
cusp  tips.    
X
Distal   D M
boundaries  
 a  line  
connecting  
the  buccal   MB cusp
and  lingual  
grooves    
 MOD  cavity  preparation  reduces  
the  mechanical  strength  by  about  
63%.  
 
81
82
Which is more important;
an adequate endodontic
treatment or an adequate
coronal restoration?

83
*All aspects of treatment have impact
on outcome.There seemed to be no
significant difference in the odds of
healing between these two
combinations.

Gillen BM, (2011) Impact of the quality of coronal restoration versus the
quality of root canal fillings on success of root canal treatment: a
systematic review and meta-analysis. J Endod 37:895–902
When to place final
filling or crown?!

85
Immediately

86
Do we need to crown
endodontically treated
teeth always?!
Do we always need
posts?!
 The  main  function  of  a  post  is  
for  the  retention  of  a  core  if  
there  is  insufficient  tooth  
substance  left  to  support  the  
coronal  final  restoration.

.H WILLIAM CHEUNG,JADAVol. 136 jada May 2005


89
*  posts  do  not  strengthen  teeth  
and  should  not  be  used  in  them  
routinely
 Preparation  of  a  post  space  and  
the  placement  of  a  post  can  
weaken  the  root  and  may  lead  to  
root  fracture.
.Heydecke G, Butz F, Strub JR.. J Dent 2001;29:427-33.
90
 The  most  common  reasons  for  vertical  
root  fracture  (VRF)  are  weakening  of  
the  residual  tooth  structure  by  caries  
and  over  preparation  and  the  post  
system  used  during  the  rehabilitation

* Tsesis I, Rosen E, Tamse A, Taschieri S, Kfir A (2010)


systematic review. J Endod 36:1455–1458
91

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