In this post I really wanted to simply go through some of the concepts involved in apical surgery and to share my thought process when considering such procedures.
So, why do some root canals fail?
1. Intra-radicular infection.
2. Extra-radicular infection.
3. True periapical cyst.
Root canal failure in most cases can be attributed to at least one of three reasons listed above. When I get a patient with failing root canal, I prefer a non-surgical re-treatment when possible to save the natural tooth. Sometimes however, this option is not possible or practical. In this case, a decision must be made whether or not endodontic surgery is a viable option.
Indications for apical surgery:
1. Conventional re-treatment is not possible or practical.
2. Re-treatment has already been done.
3. Biopsy is necessary.
So, at this point in a treatment planning algorithm, a clinician must evaluate the tooth in question and together with the patient choose the course of treatment.
Is it just better to extract the tooth and place an implant? In many cases it is.
Case selection and surgical skills!!!!! These two are paramount when considering apical surgery!
Case selection, in my mind, simply involves patient factors (medical history etc.) and “tooth” factors. I will concentrate on “tooth” factors.
Here are some of the things I look at during evaluation for possible apical surgery:
1. Proximity of the apical lesion to vital anatomical structures. For example, if the apex of tooth #29 is “sitting” on a mental foramen, apical surgery is contraindicated and an implant, bridge or intentional replantation (to be discussed in future posts) should be considered.
2. If there are deep pockets or fractures – implant! I need crestal bone around the tooth to give me better prognosis.
3. How deep is the vestibule? Lets say on a lower molar, typically lower second molars, if there is a thick buccal plate and a shallow vestibule, I will typically recommend an extraction and an implant because the apical surgery will destroy lots of good bone and in a case like this, an implant will be less traumatic. Conversely, if the vestibule is deep, the surgical access is easier and I am more likely to choose apical surgery option.
4. Size of the lesion – the larger, the worse! There is no “cut and dry” rule here. We do know however that apical surgery performed on a lesion more than 5mm in diameter tend to have a lower chance for healing.
5. Existing restoration is to be considered and also intangibles.
Besides all the obvious, like basic principles of flap design and tissue handling, the following should be done during apical surgery:
1. Periapical granuloma/cyst should be removed.
2. Must resect the root(s), best completed at a 3mm level from the apex.
3. Must place root-end filling(s) and according to research best material for that appears to be MTA. It is desirable to make the root-end preparation and therefor a root-end filling as long as possible to prevent apical leakage.
4. If the root-end filling is not placed, failure will follow!
5. During the root-end preparation – isthmus (if present) between canals MUST be incorporated into the preparation and sealed. Often isthmus is present on MB root of an upper molar (between MB1 and MB2), lower anteriors, upper premolars and lower molars (between buccal and lingual canals)
6. In order to achieve best possible outcomes, surgical operating microscope and ultrasonic instrumentation should be used.
30 year old healthy male presented with the swelling around #13. Periapical area is present on the radiograph. Diagnosis #13 failing root canal with acute periapical abscess.
Options: re-treatment with the post removal and a new crown, implant supported crown or apical surgery.
In this case, my patient opted for apical surgery.
Full periosteal flap was raised and the periapical lesion was curretted out. Roots were then resected. In this case, untreated palatal root was discovered.
Both 2 year follow-up radiographs show complete periapical healing, tooth is asymptomatic and functional.
50 year old woman with controlled hypertension, reported persistent discomfort in the periapical area associated with tooth #7, previous root canal was done by an endodontist. Diagnosis #7 Previously treated root canal with chronic periapical periodontitis.
At the 3 year follow up, tooth is asymptomatic and functional, radiograph shows a complete healing with the classic “star burst” appearance of a periapical scar.
34 year old healthy male reported a “bubble” on his gum.
Diagnosis: #30 previously treated root canal with chronic periapical abscess.
Separated instrument is “peeking” out of the mesial root. Large periapical lesion.
No perio probings above 3mm, new crown placed 3 weeks ago.
Mesial and distal roots were resected and MTA root-end fillings were placed. Isthmus was also prepared and sealed between MB and ML canals.
At one year, tooth #30 is asymptomatic and functional. Radiograph shows complete periapical healing.