Treatment Objective of Endodontic Surgery
Many dentistsl believe that the objective of endodontic surgery is to eliminate infected root apicies and/or periapical tissue. Often endodontic surgery is referred to incorrectly as an apicoectomy.
Actually, apicoectomy by itself is seldom enough to resolve root canal failures. The purpose of an apicoecomy is only to allow us to read the root and examine the canals. To seal the canals, some form of retrofilling is usually necessary.
Apicoectomy may be considered definite treatment, however, in cases of mechanical failure such as apical blockage or perforation. Such complications may result in failure of an otherwise perfectly obturated root canal system. Surgical removal of the untreated apical portion of the root will correct the problem.
Apicoectomy is merely one step toward the final objective - the retroseal.
Retroseal is the process that finally resolves most endodontic failures. Since the 1950s most clinicians have realized that virtually all failures result from leaking root canal systems. The often quoted Washington Study attributed root canal failures to apical percolation (63.46%), operator error (14.42%) root perforation (9.61%), calcified canals (3.85%), broken instrument (.96%), or case poor selection. Apicoectomy and retroseal can reverse all of these errors except improper case selection and some types of operator error.
It should be emphasized that endodontic surgery is not to be used instead of conventional endodontics. Surgery is indicated when conventional techniques cannot be used.
Indications for Endodontic Surgery
There are nine indications for resorting to endodontic surgery, and they are as follows:
1. Aberrant Anatomy
Maxillary molars, mandibular incisors, and mandibular first premolars are often problematic simply by virtue of their anatomy.
At least 50% of all maxillary molars have a second canal in the mesiobuccal root. The ones that start in the pulp chamber are easy to clean and fill, but if the canal divides part of the way down the canal, diagnosis and obturation are difficult or impossible.
Thank goodness lower anteriors are the least treated of all teeth in the mouth, because two thirds of them have two canals, and half of those have a second apical foramen. Normal X-ray angulation does not reveal these potential problems.
Lower premolars (bicuspids) have a mesial invagination (groove) of the root sheath, formed during embryogenesis. One of the diagnostic signs of a lower first premolar is the mesial groove. The invagination of the root often creates a second canal, but fortunately, those second canals usually calcify shut. If they do not, endodontic failure may result.
2. Conventionally Blocked Apices
If you have a case with a post and core that would have to be removed prior to conventional retreatment, and such removal would jeopardize the ultimate prognosis of the case, surgery is the most conservative treatment.
Endodontic surgery usually takes less than 30 minutes and is is successful most of the time.
3. Iatrogenic Repair
Sometimes the only way to remove a broken file is with endodontic surgery. If a portion of the broken file protrudes through the apex, surgery is indicated.
4. Acute Pain
When a patient remains in so much pain that there seems to be no other relief. Often the tooth has been opened for drainage, but there is no relief. The tooth remains exquisitely painful to the touch.
The tooth and tissue are numbed. As soon as the pushed back the tissue, pus may be expelled, relieving the pressure, and the patient will experience immediate comfort.
When you achieve this type of drainage, it¹s important that you do the root canal right then. There¹s no reason not to.
You can see the apex, so quickly clean and shape the canal. File long, flush and dry with the three-way syringe. Push a master point through the apex, grab it with a pair of cotton pliers, pull it tight, and cut off the point.
If treatment is delayed, it may leave the periapical area open to further infection. It only takes 10 or 12 minutes to complete the case at the time of surgery, and the patient will go home and start getting better right away.
If a patient has cellulitis, however, that is not the time to do endodontic surgery.
The local anesthetic will not work because the pH is so low the anesthetic is neutralized. When you make an incision, nothing but blood comes out. You try to manipulate the tissue, and it feels like the hardest rubber you can imagine. Tese patients should be placed on a strong antibiotic regime until the swelling subsides.
5. Persistent Cyst
The most misunderstood area in all of endodontic surgery is the notion that all cysts must be completely removed to promote healing. If root canal problem is completed, then the cystic area will reverse. Therefore, 100% enucleation of the cyst is not necessary. If the cyst starts to encroach on sensitive anatomy, only a portion of it should be carefully removed. A cystic area will not recur following complete sealing of the apex.
If a cyst is removed, it should be sent it for a biopsy. If it's worth taking out, it¹s worth sending out for biopsy. This is standard of care in the endodontic community.
6. Cracked root
Cracked roots are very difficult to diagnose. When you find one, you can often do a root resection at the bottom of the crack. When the cracked portion is removed, the typical narrow, deep pocket will disappear.
7. Perforated Apex
The real problem with root perforation is that a portion of the canal is left unfilled. Apicoectomy removes the unfilled section of the canal, and retrofilling seals the new apex.
Raising a flap is a tremendous diagnostic tool. You usually will see the cause of the problem and be able to treat it immediately.
9. Treatment alternatives
You often can save the patient a lot of time and money with apical surgery. It is often quicker and more cost effective to do an apicoectomy and retrofill than to remove and replace a post, core, and crown.
Silver point too long? Raise a flap
and tap it back up and out of the canal.
The fear of exposing the maxillary sinus causes great hesitation among many GPs. If you use the proper flap design (full thickness), opening the maxillary sinus is not a problem. The patient should be warned not to blow his nose for 36 hours and put on antibiotics. Within minutes of replacing the flap, the vascularity will be re-established will begin.
Once it is found that the sinus is not a problem, access can be gained to the palatal root of molars and premolars through the sinus, and that approach is much more predictable than raising a palatal flap. Use fiber-optic illumination for good visibility in the sinus.
Usually when a flap is lifted, it will be found that a hole in the bone or a discoloration of the osseous structure is present. The granuloma usually erodes the buccal plate. If that has not happened, the high buccal approach to safely locate the root apex is indicated.
For the high buccal approach, a small window 2mm to 3mm below the crest of the bone to locate the root is performed, and then the root is traced to the apex. Slowly the window is enlarged apically to the root apex.
Molar roots are the most difficult to locate.
If the canal length is known, a rubber stopper on a file aligned over the long axis of the involved tooth helps pinpoint the apical area. This technique only works for straight- rooted teeth, and in general is not applicable to posterior teeth.