NS-ReRCT mandibular molars Flashcards
What anatomical limitations should a clinician consider when choosing the most optimal treatment option for mandibular 2nd molars with post‐treatment periapical disease?
Generally, when initial root canal treatment results in post‐treatment disease, there are four basic treatment options (Roda & Gettleman 2016):
1. Do nothing
2. Extraction
3. Non‐surgical re‐treatment
4. Surgical treatment – Periapical surgery, replanta-
tion, etc.
There are multitudes of factors that clinicians
should consider before choosing the most optimal treatment option.The patient’s medical condition, anatomical limitations, the tooth’s restorability, and functional value of the tooth are fundamental elements. Favorable outcome depends on the successful elimination of the cause of the post‐treat- ment disease.
Doing nothing does not resolve the post‐treatment disease. Clinicians should respect the patient’s decision but inform the patient of the risks of non‐ treatment, including possible progression to more advanced stages of the disease. Clinicians should advise the patient to treat the problem in a way protective of their systemic health.The patient’s decision should be documented in the record.
Extraction of a mandibular 2nd molar can cause loss of function. A bridge can be placed if there is a well erupted 3rd molar in the distal area with good plaque control. However, bridge construction is usually problematic due to a short clinical crown.
A dental implant can be the most optimal treatment option in restoring the function, provided that the patient is not medically compromised for surgical procedures. Patients who have taken bisphospho- nates for osteoporosis need to be evaluated for potential development of osteonecrosis of the jaw after extraction (AdvisoryTask Force 2007).The location of the inferior alveolar canal can be a limiting factor in proper placement of a dental implant.
Mandibular 2nd molars are the most frequently cracked teeth because of functional and parafunctional stress. Cracked teeth restored via root canal treatment with periodontal probing depth of more than 6 mm is a significant prognostic factor for extraction (Kang,
Kim & Kim 2016). If there is a parafunctional habit, an occlusal guard should be provided to minimize the stress that contributes to cracks.
Non‐surgical re‐treatment can be an excellent treatment modality when there is a reasonable probability of securing full access to the canals to eliminate the intraradicular microbial pathogens. However, insufficient working space in the posterior mandible can make this treatment option challeng- ing. In the mandibular 2nd molar, accessing the mesial canal is more difficult than accessing the distal canal due to the angle of the canals in rela- tionship with the line of sight of the operating clinician. Clinical conditions, such as acute infection, temporomandibular dysfunction, and trismus, can further impair the clinician’s ability to access the canals of the mandibular 2nd molar.
In mandibular 2nd molars, the option of periapi- cal surgery is generally prohibitive due to the thickness of the buccal cortical plate and the loca- tion of the inferior alveolar nerve (Burklein, Grund & Schafer 2015). Preoperative CBCT analysis can be helpful to survey the anatomical structure. With the risks imposed by anatomical structure, intentional replantation can be considered if root morphology is in merged shape which makes the replantation process more amenable.
Finally, clinicians should assess their own skill set to meet the level of difficulty before deciding to initiate any treatment modality. “Do no harm” is a critical ethical standard that every clinician sub- scribes to. If the case exceeds the clinician’s level of expertise, referral to a specialist should be an option in order to safeguard or advance the welfare of the patients (American Dental Association 2016).
What is the rationale for performing non‐surgical endodontic re‐treatment?
The rationale of root canal treatment remains unequivocally consistent in treatment of primary apical periodontitis or post‐treatment periapical disease. Eliminating pathogens and preventing them from re‐establishing in the root canal space is the principal goal of root canal treatment.
Intraradicular biofilms are generally observed in the apical segment of approximately 80% of the root caals of teeth with primary or post‐treatment apical periodontitis (Siqueira & Rocas 2016). Procedural errors, such as a missed canal, a poorly negotiated canal, ledges, separation of instrument, an obstructed canal, or a poorly obturated canal, can contribute to persistent infection‐harboring micro‐ organisms in the complex canal system. Provided that the canal space can be fully accessed and negotiated, non‐surgical re‐treatment has a strong advantage in elimination of the intraradicular biofilm over surgical endodontic treatment. From a long‐term perspective, the outcome of non‐surgical re‐treatment is higher than endodontic surgery (Torabinejad et al. 2009).
In the case of retreating roots with a missed canal and periapical radiolucency, the procedure should be regarded as initial root canal treatment rather than re‐treatment, since the canal was never treated previously.The correct outcome estimate of re‐treat- ment of a missed canal should be 86%, identical to the outcome of initial non‐surgical root canal treat- ment of necrotic pulp with periapical radiolucency (Sjogren, Hagglund & Sundqvist 1990).
Micro‐organisms can be also reintroduced to the root canal system through microleakage.The source of the microleakage should be identified and removed. During the course of non‐surgical re‐ treatment, defective restorations and hidden recur- rent caries can be identified and removed to prevent microleakage.
How does 3‐D CBCT imaging aid in diagnosis and treatment planning for mandibular 2nd molar with post‐treatment disease?
When the etiology of the diagnosis is identified, the choice of treatment option becomes clear. Clinicians’ decisions are bound by the quality of the diagnostic information available to them. 3‐D CBCT image is not only superior in detecting periapical lesions, but offers 3‐D perspectives of the morphology of the tooth and the adjacent anatomical structure. It is important to notice that treatment plan modification was made in approximately 62% of the cases when additional information was provided by preoperative CBCT imaging (Ee, Fayad & Johnson 2014).
In the case of non‐surgical re‐treatment, clinicians can locate the canals that were not treated with previous root canal treatment accurately. According to Karabucak et al. (2016), the overall incidence of missed canals is 23%.The maxillary molars had the highest incidence (40.1%) of missed canals. MB2 was the most frequently missed canal in maxillary molars. In mandibular 1st molars, 65% of missed canals were second distal canal. 78% of missed canals in mandibular 2nd molars were in the mesial root.The prevalence of apical lesion in teeth with missed canal was 82.8%. A tooth with a missed canal was 4.38 times more likely to be associated with a lesion.
A CBCT image can also provide information on navigating through the canal space, showing findings such as calcification, separated instrument, bifurcation, or dilaceration. Additional information on the location of the inferior alveolar nerve or the relationship with the maxillary sinus floor can be vital in detecting the extent of the periapical pathology and setting the safe boundaries of the endodontic treatment.
Why would a clinician choose to perform re‐treatment selectively rather than for all the roots of the tooth?
With the use of 3‐D CBCT imaging and dental operating microscope, clinicians are able to accurately identify the root and navigate the root canal space with higher precision. For example, in cases of multirooted teeth such as mandibular 2nd molars, clinicians can isolate and limit the re‐treatment(s) on root(s) clearly showing periapical pathosis (Nudera 2015). By carrying out re‐treatment procedures targeting those roots with definite problems, clinicians can avoid performing unnecessary and potentially damaging re‐treatment procedures in otherwise healthy roots.This selective approach can help resolve the clinical problems with effective precision while minimizing the risks of non‐surgical re‐treatment procedures such as perforation or fracture.
How do the procedural steps involved in non‐ surgical re‐treatment differ from initial non‐surgical root canal treatment?
Even though initial non‐surgical root canal treat- ment and non‐surgical re‐treatment share the identi- cal principle, prevention of re‐establishment of pathogens after their elimination from the root canal space, the difference between them lies in the presence of previous treatment.
The patient often asks why the initial root canal treatment did not work and how the non‐surgical re‐treatment will work. In educating the patient regarding the rationale and strategy of non‐surgical re‐treatment, clinicians should focus on the facts discovered in the diagnostic process and how to achieve the treatment objectives. Clinicians should refrain from making any judgmental comments about the work that had been rendered previously.
In non‐surgical re‐treatment, uncertainties of managing the potential presence of undetected perforation, ledges, resorptions, calcified canals, separated instrument, types of existing root filling materials, and/or fracture exist at a higher level The difficulties of making access through sophisti- cated restorations and disassembling of post and core can make the re‐treatment process more time consuming and tedious than initial endodontic treatment procedures. These inherent higher risks and difficulties associated with non‐surgical re‐ treatment require an advanced level of clinical expertise and greater understanding on the patient’s part
