May 10, 2022
by Robert E. Grover, DDS; Kenneth S. Serota, DDS, MMSc
The unceasing innovations and iterations in dental technologies and materials has taken the sophistication of treatment modalities to an historic level. However, when we are focused on the newness, the thrill of the outcome, we fail to pay attention to the purpose of the activity. Case in point; dental implants were initially considered the gold standard for compromised tooth replacement despite reports that endodontic therapies ensured functionality over time to be in the range of 91 percent to 97 percent.1 The newness became tarnished by reports that peri-implantitis and peri-mucositis showed a mean weighted prevalence rate of 43 percent across Europe and 22 percent across South and North America.2 A myriad of factors influences the initiation and progression of the disease, unfortunately, the treatment of peri-implant diseases is at best favorable in the short term with a high rate of persistent inflammation and recurrence.3 A study by Guarnieri et al4 showed that in chronic periodontal patients, active periodontal therapy followed by long-term regular periodontal maintenance was successful in keeping the majority of periodontally compromised teeth. In the same patients, a higher tendency for implant loss than tooth loss was found. This series of case reports will provide decision guide categories for best practices which facilitate retention of compromised teeth using endodontic therapies.
Perhaps the most important advantage of CBCT in endodontics is that it demonstrates anatomic features in 3D that intraoral, panoramic, and cephalometric images cannot. In addition, because reconstruction of CBCT data is performed natively using a personal computer, data can be reoriented in their true spatial relationships.5
In October of 2015, a 55-year-old male patient, previously seen for treatment in the office, self-referred for a second opinion regarding the recommended removal of a suspected fractured tooth in the maxillary right quadrant. He reported that a soft swelling had become apparent over the past week. Clinical examination noted fluctuant swelling between teeth #s 1.5 and 1.4, and a 12mm probe defect was detected along the mesial-buccal line angle of tooth #1.5.
The patient provided a periapical radiograph showing a mesial-proximal peri-radicular radiolucency [PRRL] associated with tooth #1.5. (Fig. 1A) The sagittal slice of the CBCT volume [Carestream CS 9000, Carestream Dental, GA] shows the extent of the lesion. (Fig. 1B) The previous root canal therapy had detected and treated the buccal canal only. The axial slice shows an untreated palatal canal. (Fig. 1C) A fiber post placed in the buccal canal was used to retain the core. The patient was advised of the misdirected anchoring pin extending into the periodontal ligament [PDL]. With the patient’s consent, it was decided to selectively treat the palatal canal.
After an interim six-week period of calcium hydroxide therapy [Ca(OH)2, UltraCal™ XS, UPI, S. Jordan UT] (Figs. 1D, 1E),6 the root canal space was obturated using a warm vertical condensation technique.7 The obturation media was expressed into a lateral branching portal of exit. (Fig. 1F) A four-year follow-up shows resolution of the lateral lesion. (Figs. 1G, 1H, I) The initial presumption of a fractured root was proven false suggesting that illusory conditions based on insufficient data acquisition are unreliable. The use of CBCT is an imperative in endodontic procedures of any kind provided ALORA principles are followed.
Root resective therapy is a treatment option for molars with advanced furcation involvement. In a study by Derks et al, mandibular molars after root resection showed a survival probability of almost 80% even 20 years after root resection.8
In October of 1998, a 39-year-old-male patient presented to the office complaining of “gum tenderness” in the mandibular right quadrant. Extensive bone loss was noted inter-proximally between teeth #’s 4.7 and 4.6, however, the periodontal status of the dentition in general was within normal limits. Pulp sensibility testing of the teeth in the mandibular right quadrant identified the pulp of tooth #4.6 to be necrotic. (Fig. 2A) It was explained to the patient that successful treatment of perio-endo lesions was in general questionable/unfavourable, dependent on the severity of bone loss, root trunk length, degree of root separation, the curvature of the root to be resected, the ability to eradicate the osseous defect, pulpal status, and the restorative and oral hygiene procedures required.
With the patient’s consent, the distal root of tooth #4.6 was resected and the overlying crown portion retained. (Fig. 2B) At some point after the amputation procedure, the referring dentist [RD] splinted teeth #’s 4.7 and 4.6 with a composite/Ribbond bridge. Twenty-two years after the initial procedure, osseous regeneration and cortication in the furcal region are evident between teeth #’s 4.7 and 4.6. (Fig. 2C)
Advancements in strategies to maintain compromised teeth in concert with a greater understanding of risk factors associated with dental implants invite a reassessment of the benefits of strategic extraction of a tooth with a questionable prognosis or of limited strategic value.9 With the use of hard and soft tissue augmentation procedures, PRF (plasma rich fibrin), minimally invasive flap design and suturing techniques in conjunction with surgical operating microscopes, it is unreasonable to sacrifice a tooth for an implant when this venerable treatment option shows favorable prognosis and success rates.10
Progressive internal resorption or those instances with perforations of the root can be distinguished from external resorption by varied radiographic techniques. In teeth with internal resorption, the radiolucent lesion “moves” with the canal when the radiographs are taken at different angles, while in external resorption the radiolucent lesion “moves” outside of the canal.11,12
In March of 1999, a 47-year-old female patient presented to the office with facial swelling; tooth #1.1 was tender to percussion. A periapical radiograph (Fig. 3A) of the maxillary anterior sextent showed large Class III and IV restorations. Tooth #1.1 exhibited peri-apical rarefaction. Tooth #2.1 showed internal resorption at the mid-root level. The patient reported that tooth #2.1 had been traumatized some 35 years prior. In the absence of CBCT imaging, it was assumed that the resorption perforated the facial aspect of the root and disrupted the overlying cortical bone.
Pulpal sensibility testing of the teeth in the anterior determined that tooth #1.1 was pulpless. The tooth was endodontically treated and obturated using a warm vertical condensation technique. Tooth #2.1 was instrumented to the incisal level of the resorptive defect, and the canal sealed with white MTA.13 Figs 3A & 3B show the pre-operative and post-operative radiographs taken in 1999. (Figs. 3C & 3D) show the healing after 21 years. Currently, there is a trend towards the use of an injectable platelet-rich fibrin (i-PRF) regenerative approach to resolve internal resorptive defects that shows great potential for long-term healing.14
In a study of 2086 cracked teeth by Krell and Caplan,15 the most common teeth demonstrating fracture were mandibular second molars (36%) followed by mandibular first molars (27%) and maxillary first molars (18%). There were no statistically significant differences in success based on pulpal diagnosis (irreversible pulpitis, 85%; necrosis, 80%; previously treated, 74%), patients’ age, sex, year of treatment, tooth type, restorative material, or number of restored surfaces at the time of examination.
In July of 2014, a 45-year-old female patient presented to the office with a chief complaint of swelling in the distal papilla of tooth #1.4 for a period of 10 days. Clinical examination revealed an occlusal amalgam restoration with a probeable seam in the distal marginal ridge [DMR]. The probe depths along the distal-buccal and lingual line angles of the tooth demonstrated an infrabony pocket of 8mm. The peri-apical radiograph taken showed a small amalgam restoration with a vertically angulated radiolucency interproximally between teeth #’s 1.4 and 1.5. (Figs. 4A & 4B) shows a fracture line extending into the mesial marginal ridge. The tooth was assessed for vitality with thermal and EPT tests which elicited no response.
The treatment options were explained to the patient; 1) removal, 3-unit fixed bridge, 2) removal, soft and hard tissue augmentation, and 3) implant retained restoration or root canal therapy and restoration with cuspal protection. The patient was advised that option 3 had a questionable prognosis; however, for financial reasons, she chose to proceed with that option.
It should be noted that management of cracked tooth syndrome varies based on the severity of the symptoms and depth of tooth structure involved. Endodontic therapy was performed using a warm vertical condensation technique. (Fig. 4C) The access preparation was sealed with a flowable and hybrid composite restoration. The radiograph taken at a six-year follow-up  showed osseous regeneration in the interproximal area eliminating the periodontal defect.
Fig. 4A-DFig. 4E
The treatment planning process demands the inclusion of a myriad of data pertaining to the status of the tooth and root structure. The Decision Guide of the American Association of Endodontics encourages the clinician to consider local and systemic case-specific issues, economics, the patient’s desires and needs, esthetics, potential adverse outcomes, and ethical factors. The treatment performed must reflect best practices for the patient’s needs [www.aae.org/treatmentoptions]
Oral Health welcomes this original article.
About the Author
Robert Grover is an Assistant Professor in Endodontics at the University of Virginia Department of Dentistry and the Virginia Commonwealth University School of Dentistry. He maintains a private practice in Endodontics in Staunton, Virginia.
Kenneth Serota is an ambassador of the SlowDentistry Foundation, the Digital Dentistry Society (Canada) and the CleanImplant Foundation. The founder of the ROOTS online forum in 2000 and the NEXUS Facebook forum in 2015, he practiced endodontics in Ontario for over 35 years.