OS Sheet #1 By Reham Kilano

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OS Sheet #1 By Reham Kilano

Post by Sura on 11/2/2012, 12:39 am

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Periapical surgery
Types of Periapical surgeries
-Curettage :Removal of a pathological lesion like cysts or granulomas
-Root amputation:surgical removal of one or more roots of a multirooted tooth. Also called radectomy
Apicoectomy is an endodontic surgical procedure whereby a tooth's root tip is removed and a root end cavity is prepared and filled with a biocompatible material.
This is not a new technique, it has been there for a long period of time and has it’s Indications and Contraindications
1-Difficult anatomical variations in the root canal that makes it hard to do a conventional RCT like Calcifications or sever curves for example; In this case a surgeon opens a flap, cuts the apex and fills the canal in a retrograde manner
2-The conventional RCT had complications like breakage of a file inside the canal that couldn’t be retrieved in a simple way
3-A lesion around the apex that is suspected to be pathological and needs to be biopsied
4-If a previous RCT had already been done and a pos/ crown was constructed but nevertheless an apical lesion is still there and the risk of breaking the tooth if we removed the post and redid the RCT is high
5- RCT problems like perforations or ledges

First of all any contraindication for a Surgery is a contraindication for apicoectomy as it includes the same procedures from LA, opening a flap…etc so we should be concerned about bleeding disorders,diabetics,hypertensive patients and so on.
1-Anatomical structures:
A-Roots of lower 4&5 are very close to the mental foramen so we have to assess the distance between them and if this risk is very high then we might go to a decision like taking the tooth out instead of doing apiceoctomy and preserving the tooth but ending up with a life-long paresthesia
B- roots of upper premolars and molars are in close proximity to the floor of the maxillary sinus,it could be even impinging it. Now an important point is that it’s not a total contraindications if the root was inside the sinus but it’s one procedure that should be done carefully and by experienced hands, another thing is that the tooth has to be a strategic tooth meaning a restorable one because it doesn’t make any sense to invade the sinus and make the procedure for a tooth that is not expected to be restored or have a short life expectancy.

2-In apicoectomy it is very important to know the crown/root ratio because it must be at least 1:1,in case the root was short then this is a contraindication for an apicoectomy because this procedure will reduce the root length even more making it less than 1:1and the tooth will no longer be stable and will start moving and will eventually be lost.
3- Before you go to apicoetomy for a tooth that already had an failure of RCT you have to identify the cause of the failure because simply you can do apicoectomy only to find out later that the cause of failure was a lateral canal that still have a vital pulp.
The procedure :
-Flap: to expose the apex
-Curettage to clean any lesions around the apex
-Osteotomy to remove part of the bone from the buccal plate that is covering the apex in order to expose it
-Put the retrograde filling and close the flap

Now considering the Flap design we have 3 main types
-Full mucoperiosteal flap :this is where we have a cervical margin cut and a vertical posterior and/or a vertical anterior releasing flaps then the dissection is done directly subperiostealy and we retract the flap
~ Advantages:
Better access and visibility
~ Disadvantages:
Recession because whenever you open a flap there is a 1-2 mm crestal bone resorption and this will be followed by gum recession because gum always follows bone. So from an esthetic point of view it’s not preferable to do a full mucoperiosteal flap in the upper anterior teeth “from 6 to 6”
One other thing on top of recession is that in the anterior area we already have good access thus good visibility so we don’t need to go for a full flap there

-Semilunar flap

-Submarginal flap: in this type we leave around 2-3 mm above the marginal gingival and we make a horizontal incision,then both anterior and posterior releasing incision so it’s just like the full mucoperiosteal flap except it’s 2-3 mm above the margin

So to sum up, when we talk about posterior teeth we’re mainly talking about full mucoperiosteal flaps but anteriorly it’s either semilunar or submarginal flaps .Now that was what they used to say before but now the use of semilnar flaps have dramatically decreased and this is due to the fact that when we close this flap it will close just above the lesion or the defect actually and this is not favorable because when we want good soft tissue healing and to avoid fenestrations we have to close the flap on sound bone because if we close it on a defect –like the apical third in this case- there will be some kind of depression and fenestration and there won’t be any good bone regeneration

Now does that mean that in all anterior teeth we use submarginal and in posteriors we use full mucoperiosteal flaps?! The answer is NO, it depends on the case, for example, if we have a huge cyst the has reached or approaching the marginal gingiva anteriorly , in this case it is a must to open a full flap to remove all the pathological lesions But again whenever it is possible, it is preferable to use the submarginal rather than the full flaps anteriorly.
So we got an access and opened a flap .. next thing is osteotomy for the bone around the apex that needs to be removed, but in cases where we have chronic infections it’s almost always that bone around the apex is already gone so we only remove the lesions around the apex to expose it and no ostotomy is performed.
How much bone we have to remove?! It is usually 7 mm in width and 3-4 mm in depth. Width should never been less than 5 because this will compromise visibility, we can use a less than 5 mm width only in one case that is if we were using the microscope (magnification effect). This is usually done by endodontists rather than surgeons.

Next step is Curettage where we clean any lesions that are around the apex and we usually do irrigation to make sure it’s a clean area and make sure to send the lesion to the lab for biopsy if we suspect any kind of pathological lesions.

Up till now we Opened a flap, made osteotomy and did curettage, what is left is apicoectomy where we cut the apex obviously!
How to cut?! 10 years ago there was this theory that got huge acceptance,that is to do the cut with a 15-20 degree bevel rather than a straight cut
The advantages lie in the better visibility while applying the filling material
The disadvantage is the fact that you might miss some lesions behind the beveled area which could be the one responsible for RCT failures and responsible for preventing full curettage
So the current saying is to do it more or less of a horizontal cut or less than 10 degree bevel
How much to cut from the tooth?! Around 3 mm this is because usually any pathological tissues and any canal ismuth and lateral canals usually lie within the last 3 mms

So as a summary we do horizontal cuts or 10 degrees bevel maximum with 3 mm cut from the apex.
Next is to prepare for a retrograde filling: we make a class one with a very small round bur, we go in the canal and clean it, at least we need 2-3 mm of a cavity then we put the end filling to seal the area to prevent contamination

Materials to be used as retrograde fillings:
1- The best material to be used is the MTA because of its radio-opacity and most importantly is that MTA induces cementum formation so the outer layer of cementum will be induced to form when we use the MTA
2- 10 years ago they used to use Amalgam but this is not good because of what is known as amalgam tattoo ,tissue reactions and discolorations .Also amalgam tends to scatter so it’s not the best choice for this matter
3- IRM,EBA,Super EBA
So the best material to use is MTA due to cementum inducing effect and the least effective is amalgam.
So we always have to put a retrograde filling to SEAL the canal.The only case where we do not put a retrograde material is when we do the apicoectomy before performing the RCT like when there is a periapical lesion that need to be taken out,then we open a flap,curettage the area, apicoectomy and then we put the Gutta percha conventionally”meaning from the canal orifice”then we thermally seal it from the apex that we already had it cut.
So if the tooth already had a previous RCT then a retrograde filling is a must, if it’s not root canal treated then we have the previously mention scenario for example.
-Success rate in apicoectomy is very high reaching from 80-90% this is due to the advancement in technology like the microscopes that we talked about and something else called the ultrasonic instruments that are used for the class one that was mention earlier but this one needs good vision that can be gained by a microscope as well.
- repeated surgeries will have around 35% success rate
-some researches say that if the apicoectomy was done at the time of the RCT it has better results
These numbers are important from a patient point of view ,so as a dentist we should be able to tell our patients about the success and failure rates.
Q: If we did an RCT and it was a failure do we go for apicoectomy or a redo?!
A: this depends on the cause of the failure if it was not enough pulp debridement or cleaning and shaping or obturation then a redo is the treatment of choice but if the cause was lateral canals or pathological lesions the an apicoectomy is the choice because no matter how many redos you will make, you’ll always end up with a failure.
** granulation tissues and granulomas respond well to RCTs while Cystic lesions do not
So bottom line is: when you see a failure case ,make sure that nothing was wrong with the RCT procedure before jumping right away to apicoectomy

1-trauma to the adjacent roots this happens mainly in anterior teeth where the roots are in close proximity to each other ,ex: if we’re working on a canine apex then the lateral and premolar roots are very close and can be easily damaged
2-trauma to vital structures like
in the lower arch
4&5(especially the 5)>> mental nerve
6&7 > ID nerve so we need to measure the distance between them and the nerve
**Obviously No apicoectomy for an 8 is performed
In the Upper arch
1&2 > floor of the nose, so attention should be paid when performing apicoectomy in that area
4,5,6,7 and sometimes even the 3> proximity to the maxillary sinus
4 > two rooted and the palatal one might be hard to reach
6&7 >> apicoectomy is done for the buccal and not the palatal roots because they are hard to reach.
>> Failures for unknown reasons do happen! And here we have 2 choices either to redo the procedure or to simply extract the tooth!
>> Apex dislodgment is another thing to worry about while performing the procedure because it could get lost in the maxillary sinus,nose…or anywhere else
>> some surgeons leave the apex-after cutting it and doing the end filling- into it’s place which is obviously wrong because the inflammation and everything related to the apex will still be there.

That’s all for today
Good luck 

عدد المساهمات : 484
النشاط : 2
تاريخ التسجيل : 2010-09-29

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