Interview with an Endodontist – Dr. Moji Bagheri

IS: What is the most common endodontic therapy that you perform? Root canals or retreats? And are the majority maxillary or mandibular dentition ? 

MB: There is a fair share of conventional root canals and retreats, maybe around 60% conventional root canals and the rest are retreats and a small percentage are surgical RCTs. Based on my experience, the majority of cases are lower molars. The lower first molars are usually the first ones to receive RCT.

IS:  Please describe the difference between reversible pulpitis vs irreversible pulpitis.  

MB: In the case of reversible pulpitis, the inflammation of the pulp is reversible meaning that the symptoms are temporary and usually as a result of a new large restoration, occlusal trauma such as hyperocclusion on the restoration or biting on some sort of hard substance such as nuts or fruit pits. In the case of irreversible pulpitis, the inflammation of the pulp is irreversible, meaning that the damage to the pulp proper is direct and beyond the ability of body to repair. In cases such a direct caries exposure, fractures as a result of severe trauma, mechanical trauma when the tooth is being prepared for restoration especially when the tooth is overheated.

MB: Apicoectomy is the final step in series of steps that is taken to salvage a tooth which otherwise would be extracted. You can think of it as being the last resort when it comes to saving teeth. Once there is sufficient evidence to determine that a retreatment will not improve the condition of a tooth or is deemed high risk for fractures. For example, due to an existing large post or in case of a bridge when the failed tooth is an abutment and saving the tooth is critical, an apicoectomy is indicated.

IS: What is the reason some PAP’s may last several years after an RCT has been performed?

MB: Some PARL’s may last for up to 5 years after the root canal treatment. Some of the factors that contribute to the prolonged presence of PARL’s are size of the initial lesion, such that larger lesions tend to last longer and heal at a slower rate. Location of the lesion is another factor that may contribute to this prolonged healing. Lesions in denser bone such as the anterior mandible tend to heal slower than lesions on the posterior maxilla, which has less cortical bone. The patient’s medical history is another factor that should be taken under consideration in such cases. Studies show that patients with diabetes, due to lower immune system function, may require more time to heal. Some of the PAP’s that tend to last can also be scar tissue in the bone.

IS: How do you diagnose a clinical fracture? Are most clinical fractures coronal or root involved? Is it possible to diagnose off of symptoms alone?

MB: Based on the classification that the AAE recognizes, the fractures are categorized as craze lines, which are only on the surface of the enamel. The second category are fractured cusps which as its name suggest, are limited to the cusp and coronal tooth structure. These can be due to a weakened marginal ridge. The third category is a cracked tooth. This type of fracture extends toward the root, without splitting the tooth, most of the time it involves the pulp chamber. We this occurring to mandibular second molars.  The long term progression of cracked teeth can eventually lead to the fourth category of fractures which is a split tooth. In this category the tooth completely splits apart and the crack crosses both marginal ridges. The final category are vertical root fractures. Unlike other types of fractures, these start in the root and extend to the coronal portion of the dentition. The diagnosis of the first four categories can be done with a clinical exam with pressure testing and radiographs. In the case of vertical root fractures, a radiographic analysis is the most accurate determining factor in diagnosis.

IS: Do optics (microscopes) help visualize lateral canals ? Is it possible to have successful endodontic therapy without the use of microscopes ?  

MB: I think one of the greatest advancements in the field of endodontics has been the use of microscope. I can say, yes, it is possible to visualize lateral canals without the use of a microscope, as long as there is a correct line of access. For example, on a lower incisor. Also, using a microscope, does not necessarily guarantee a successful treatment. Using a microscope, however, can increase the success rate and accuracy of treatment. Overall, the expertise, knowledge and skills of the clinician are more pivotal to a successful outcome.

MB: I think the most important aspect of root canal treatment is the criteria for case selection by the practitioner. I think the GP that chooses to perform a procedure, should be well aware of his or her limitations and skills and what is best for the patient.  Several reasons that we see failures in root canals done by GP’s include: 1) Improper amount and type of irrigation. 2) Improper use of the rubber dam and/or poor isolation. This is essential to keep the area as sterile as possible. 3) Selection of obturation material and techniques. A material such as Thermafil is very technique sensitive and if not done properly, it would certainly lead to root canal failure.

IS: Is MTA the best and only option for perforated canals? What is the reason for its efficacy?

MB: MTA has been around for a long time and its usage has been researched extensively with for perforation repairs with great results. MTA, however, is not the only material choice. What makes MTA an ideal material for perforations are its biocompatibility, physical properties and antibacterial effects.  There are newer materials which have emerged in the biomaterials market that can compete with MTA. ESRR is a newer bioceramic cement that has been gaining popularity as of late. It has good results comparable to MTA and due to its putty-like consistency, it has easier handling ability than MTA. Despite newer materials, MTA is still the most widely used root repair material.

IS:  How do some teeth lead to necrosis while being asymptomatic?

MB: In rare instances, teeth can become necrotic without the patient really feeling any discomfort or pain. This is an issue that arises with trauma or any instance that could alter the pulpal blood flow. Based on my personal experience, the most frequent circumstances that could lead to teeth becoming necrotic while asymptomatic include teeth that have been restored for a prolonged period with crowns, or large metal restorations with recurrent caries. In addition adult teeth that have been traumatized fit could fit in this category. Patients often don’t complain about any pain but once the tooth is accessed, the necrotic tissue, or lack thereof becomes evident. These situations are seen mostly in the older adult patient population.

IS: If a patient has pain when pressing down to chew, but no pain or sensitivity with hot or cold temperatures, what is the most probable diagnosis?

MB: Pain to chewing is caused from a thickened ligament. A thickened ligament can be caused by endodontic or periodontal problems or even hyperocclusion. A tooth with no sensitivity to hot or cold most likely has a hyperocclusion or a periodontal problem. No endodontic treatment is necessary. In these cases the pain is significantly alleviated upon occlusal adjustment and correction of the bite.

IS: Do you do root canal therapy on patients with fibromyalgia patients? If so have you had experience with them and if so what are your thoughts on dental-facial pain as it relates to fibromyalgia?

MB:  When it comes to fibromyalgia the situation is rather complicated. Because the source of the pain is non-odontogenic therefore the root canal treatment is not often the answer to the problem and may not resolve all the issues that patient is having, unless there are other obvious signs of pulpal involvement such as direct carious pulp exposure, root canal treatment is not the first line in treatment. In such instances, patients are usually treated for fibromyalgia first by detecting the source of the pain, often the Trigeminal ganglion, and only when it’s alleviated, then other issues are examined and treated as necessary. Personally I have dealt with a few patients while in residency and they were eye-opening experiences as they allowed me to work in an interdisciplinary setting with Orofacial pain specialist to achieve a common goal. The approach to these cases often involved a detailed interview of the patient which revealed a lot of information about the nature of the pain that they were having. After that, the determination of origin of pain which in cases of fibromyalgia, was non-odontogenic. Once the source was identified, the treatment was done by the OFP specialist to resolve the issue usually with medications like Neurontin. After that, teeth were examined for potential root canal treatment.