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As seen in Dentistry Today: Improving the GP-Endodontist Relationship: The Use of CBCT to Enhance Communication

Communication is one of the cornerstones of major companies such as Amazon, Walmart, and Costco. A breakdown in communication can decrease a company’s production, which could ultimately affect its most important assets: employees and customers. On a much smaller scale, communication is also the key to the general (restorative) dentist-endodontist relationship. According to Cymerman,1 the general practitioner (GP) needs to communicate any restorative needs to the endodontist before initiation of the endodontic treatment and vice versa. The endodontist needs to do the same before the tooth is restored.

In addition to a written referral, a dialogue between both parties is in order. In this age of email, texts, and social media, the telephone is often left behind. Although more time consuming, a direct conversation between the endodontist and the referring dentist can result in a more efficient way to treat their mutual patient. By discussing all aspects of treatment, such as concerns and expectations, both parties can better understand each other. In a study by Mills,2 58.6% of endodontists responded to a questionnaire about the relationship between the endodontist and the general dentist. The responses showed different opinions plus inaccurate information that might affect how both the dentist and endodontist understand each other. The endodontists had concerns related to emergencies, mid-treatment takeovers, and the dependency on the referring dentist.2 Therefore, the important goal is to reduce misunderstandings while increasing the clarity of instructions and any other pertinent information shared by both parties.

Starting With the Referral
It all begins with the restorative dentist’s referral since most patients do not go directly to an endodontist. First, these 3 pieces of information are essential for the restorative dentist to adequately communicate to the endodontist.

Figure 1. Two-dimensional imaging depicts enough information to make a diagnosis of a vertical root fracture on the lower left second molar.

Intended Restoration: Complete coverage, partial coverage, or a bonded restoration. If the restorative goal is a full crown, most times this requires removal of nearly all supragingival enamel. Therefore, it will be extremely important to keep the access opening as small as possible in order to retain as much intact tooth structure as possible. This becomes even more important for anterior teeth. In the event of inadequately retained tooth structure, will a post be needed to help rebuild the crown? If so, will the restorative dentist want the endodontist to prepare the post hole and furnish the post?

Partial Coverage: If a three-fourths crown or onlay will be planned on a posterior tooth, all the cusps will be protected and, generally, no post will be needed. If porcelain veneers are anticipated, especially on anterior teeth, will the restorative dentist want a tooth-colored post that will not discolor the final result? Also, it is important to make sure the endodontist thoroughly cleans the pulp and any residual caries, dried blood, or resin-stained dentin, if possible, so it will not show through.

Figure 2a. The patient presents with pain on the lower left first bicuspid, but 2-D imaging does not detect any pathology.Figure 2b. A 3-D image detects a lateral lesion on the same tooth.

Bonded Restoration: If the tooth has adequate dentin and enamel, then the access opening can simply be bonded with composite resin. However, if mesial or distal microcracks are present, it may be wise to advise cusp protection or, certainly, to follow out the microcracks. The endodontist is generally in a good position to advise just how deep these microcracks are since transillumination from inside the access opening may reveal the depth of the microcrack. Bucco-lingual cracks are also important to check, although there is generally more enamel in a posterior tooth. Regardless, it is an essential task that endodontists can and should perform, especially if the referring dentist has not utilized an intraoral camera or another transillumination device to help determine his or her intended restoration. Although written communication is necessary, consider a phone call to discuss the findings.

Figure 3a. A preoperative radiograph of failing endodontic treatment on the lower left second molar.Figure 3b. A 3-D image of the same tooth detects a horizontal fracture.
Figure 3c. A 3-D image of the same tooth depicts a mesial vertical root fracture.

Time for Restorative Treatment
Generally speaking, sufficient time needs to exist between completion of the endodontic treatment and the beginning of restorative treatment. One exception is if there is insufficient tooth structure or there are crack lines in the access; then an interim restoration should be started as soon as possible to make sure the tooth does not erupt, change position, or fracture. One of the worst things to happen is if the referring dentist places a fixed restoration on the endodontically treated tooth only to find out the tooth will need to be retreated.

Warning: Too many endodontists routinely refer the patient back to the referring dentist with the instruction to place a full crown on the endodontically treated tooth. This may well be the wrong advice, especially if the treated tooth has more than adequate tooth structure.

Once the interaction dynamics between the general dentist and endodontist are clear, the next step is to determine how best to deliver and receive patient information.

In the Beginning
In 1895, the standard radiograph was discovered by Wilhelm Conrad Roentgen. These small radiographs were the only source of communication between the endodontist and general dentist. The radiograph was placed in a holder/mount, and notes were written by hand or typed that expressed the concerns or problems the endodontist faced during treatment. Many years later, digital radiography using sensors instead of e-speed film curbed the use of standard radiographs by allowing the patient to be able to achieve the lowest amount of radiation possible and stay in line with ALARA (As Low As Reasonably Achievable) and still get a high-quality radiograph that can be emailed or scanned and formatted onto office letterhead for communication purposes. This is now the gold standard for most endodontic and general dentist practices. Other forms of communication can include imaging from an intraoral camera and/or a microscope that takes digital images that can be sent to the dentist. These technological marvels were seen as priceless when used to transmit detailed problems to the referring dentist. So, what more could we need? Welcome to the communication era 2.0.

Figure 4a. A pre-op radiograph of the upper right second molar. Note the possible calcified MB canal. The tooth was painful to pressure.Figure 4b. A 3-D image of the same tooth detects a large, missed mesial buccal canal that does not appear to be calcified.
Figure 4c. A 3-D image of the same tooth detects external resorption on mesial buccal root.

The Future is Now
No doubt, the state-of-the-art technology in endodontics, including many other aspects of dentistry, is cone beam radiography. It has been documented that 2-D imaging has limited use in terms of being diagnostic because of anatomical superimposition, distortion, exposure, and processing errors. However, 2-D radiographs are less expensive, have a much lower radiation dose, and may have a higher resolution than CBCT images. More importantly, 2-D imaging often is sufficient for making a correct diagnosis (Figure 1). This is important because CBCT imaging is expensive and has a higher radiation dose, and, in addition, radiation artifacts are common.3-5 Therefore, the standard for making a diagnosis and confirming this with the referring dentist is still 2-D imaging. Nevertheless, with better advances in the imaging sensors, startling 2-D images can be achieved. Therefore, to decide whether to use 2-D or 3-D imaging to diagnose a case depends on parameters. Al-Salehi et al6 concluded from their study of 34 cases (albeit a small number) that the routine use of CBCT imaging is not justified for all cases and, therefore, carefully selected use is appropriate. Yet, it is the difficult case where no pathology is evident on the radiograph and the patient has no clinical symptoms but continues to have pain in a particular area or quadrant that is the perfect scenario for using 3-D imaging. According to de Paula-Silva et al,7 CBCT imaging can detect periapical pathosis before it can be seen on 2-D imaging (Figures 2a and 2b).

Figure 5a. A pre-op radiograph of failing endodontic treatment on the upper left first molar. Note presences of caries on all 3 teeth.Figure 5b. A 3-D image of the same tooth shows a calcified second mesial buccal canal that cannot be detected on 2-D images.

Once the CBCT scan is taken and a diagnosis is made, this information needs to get back to the referring dentist in a clear and concise manner. Most times, a written communication telling what the CBCT shows, along with supporting 3-D images, will be more than sufficient. However, if the endodontist feels that what he or she has found in the CBCT scan might interfere with or complicate the referring dentist’s plans, a phone call definitely should be planned as well.

CBCT has the ability to see the same tooth or teeth in 4 different views. According to the American Association of Endodontists and the American Academy of Oral and Maxillofacial Radiology joint position statement on CBCT, limited field of view (FOV) CBCT should be used for diagnosis in patients with “non-specific clinical signs and symptoms associated with untreated or previously treated teeth.”8 Therefore, using 3-D imaging in limited FOV, images are displayed in axial, sagittal, coronal, and 3-D rendering views. Each view allows visualization of dental structures in their actual spatial representation. The axial view enables the endodontist to look for defects, horizontal fractures (Figures 3a to 3c), and, most importantly, missed and calcified canal spaces (Figures 4 and 5), which inevitably can dictate whether to treat or not to treat, depending on the complexity of the case. The sagittal view gives the endodontist a 180° lateral view of the tooth or teeth. This view can detect vertical root fractures (Figure 3c), crown/resorptive defects (apical, internal, external) (Figures 4a to 4c), apical lesions, and the extent of vertical bone loss around a root or roots that also determine the prognosis of a case. The coronal view can help the clinician visualize the tooth or teeth in a lingual-to-buccal orientation. When discussing a patient with the referring dentist, the 3-D rendering or 3-D reconstruction of the teeth and bone together can provide a 1:1 scale that can show an exact view of dental structures, which can facilitate effective communication between both dentists.9 The ability to see fractures, defects (external) (Figures 6a and 6b), and the true amount of bone loss around the root or roots is essential in making a diagnosis and may well alter the pre-planned restoration. Thus, our goal is to not subject a patient to needless endodontic treatment as well as to avoid a potential failed restorative treatment.

Figure 6a. A pre-op radiograph of the lower right second molar that was painful to pressure.Figure 6b. On 3-D reconstruction of the same tooth, the distal root has external resorption that is not depicted in 2-D imaging.
Figure 7a. A pre-op radiograph of the lower left first premolar with a large apical lesion.Figure 7b. The measuring tool can denote the size of the apical lesion.

Three-dimensional imaging incorporates functions to help in relaying information to the referring dentist, such as a measurement tool to acquire the size of an apical lesion or defect9 (Figures 7a and 7b). This information is crucial because the larger the apical lesion, the more time it may take to heal, which may also affect the referring dentist’s restorative plans. If the defect, such as external resorption, is large, the prognosis becomes guarded to poor due to leakage and the potential for recontamination.

CLOSING COMMENTS
The reality of how dentistry is being practiced today continues to evolve, especially in the field of endodontics. The restorative dentist must be able to reasonably predict the success of his or her treatment.10 Therefore, it is becoming increasingly apparent that CBCT may well be the best option to evaluate if any teeth need endodontic treatment before extensive restorative care is undertaken. Thus, this enhanced technology can fulfill the ever-important need for better understanding and communication between the restorative dentist and endodontist, especially in treating their most important asset—their patient.


References

  1. Koch K, Brave D. The general dentist-endodontist relationship. Dentaltown. May 2011. http://www.dentaltown.com/magazine/articles/3254/the-general-dentist-endodontist-relationship. Accessed February 13, 2018.
  2. Mills JC. A study of the relationship between the endodontist and the general dentist. J Endod. 1984;10:110-114.
  3. Christell H, Birch S, Hedesiu M, et al; SEDENTEXCT consortium. Variation in costs of cone beam CT examinations among healthcare systems. Dentomaxillofac Radiol. 2012;41:571-577.
  4. Al-Okshi A, Lindh C, Salé H, et al. Effective dose of cone beam CT (CBCT) of the facial skeleton: a systematic review. Br J Radiol. 2015;88:20140658.
  5. Schulze R, Heil U, Gross D, et al. Artefacts in CBCT: a review. Dentomaxillofac Radiol. 2011;40:265-273.
  6. Al-Salehi SK, Horner K. Impact of cone beam computed tomography (CBCT) on diagnostic thinking in endodontics of posterior teeth: a before-after study. J Dent. 2016;53:57-63.
  7. de Paula-Silva FW, Wu MK, Leonardo MR, et al. Accuracy of periapical radiography and cone-beam computed tomography scans in diagnosing apical periodontitis using histopathological findings as a gold standard. J Endod. 2009;35:1009-1012.
  8. Fayed MI, Nair M, Levin MD, et al. AAE and AAOMR joint position statement: Use of cone beam computed tomography in endodontics 2015 update. Oral Surg Oral Med Oral Pathol Oral Radiol. 2015;120:508-512.
  9. Carestream Dental. CS 9000 3D. Innovation, in Reach [brochure]. Atlanta, GA: Carestream Dental; 2012.
  10. Goldstein RE, Chu SJ, Lee E, et al. Ronald E. Goldstein’s Esthetics in Dentistry. 3rd ed. Hoboken, NJ: John Wiley & Sons; 2018.

Dr. Ronald Goldstein is currently a clinical professor of restorative science at the Dental College of Georgia at Augusta University, Augusta, Ga; an adjunct clinical professor of prosthodontics at the Boston University (BU) Henry M. Goldman School of Dental Medicine (GSDM); and an adjunct professor of restorative dentistry at the University of Texas Health Science Center at San Antonio. He is co-founder and past president of the American Academy of Esthetic Dentistry and past president of the International Federation of Esthetic Dentistry. In 2008, Dr. Goldstein founded the Tomorrow’s Smiles program under the National Children’s Oral Health Foundation to help deserving adolescents receive cosmetic dental treatment and enjoy the benefits of a healthy smile. He is a contributor to 11 published texts and author of the 2-volume, 3rd edition 2018 text Esthetics in Dentistry  (Wiley). He is coauthor of Bleaching Teeth, Porcelain Laminate Veneers, Porcelain and Composite Inlays and Onlays, Complete Dental Bleaching, and Imaging in Esthetic Dentistry (Quintessence Publishing). His best-selling consumer book, Change Your Smile, now in its fourth edition, has had more than 2,000,000 readers and has been translated into 12 languages. He is currently on the editorial advisory boards of Dentistry Today and Inside Dentistry. He can be reached via email at esthetics@mindspring.com.

Dr. Kenneth Goldstein is a graduate of BU GSDM, where he received a Fellowship in General Dentistry. He later earned his degree in endodontics at the University of Southern California School of Dentistry. Dr. Goldstein has taught and lectured in the field of endodontics. He is a specialist member of numerous organizations, such as the ADA, the American Association of Endodontists, the Georgia Association of Endodontists, the Georgia Dental Association, the Hinman Dental Society and the Northwestern District Dental Society. He can be reached via email at g_ken@bellsouth.net.

Disclosures: The authors report no disclosures.

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