Abstract

Objective: Radiographic “J-shaped” lesions can be present in teeth without vertical root fractures (VRF). The objective of this study was to assess the recommended treatment plan in this type of case.

Methods: Radiographs and clinical data from fifteen necrotic or endodontically-treated teeth with radiographic/tomographic “J-shaped” or “halo” endodontic lesions were presented during a lecture to 323 evaluators for treatment selection. The selection of treatments (endodontic therapy, periodontal therapy, endo-perio combined treatment or extraction) and the influence of patient/tooth-related factors in treatment decision planning were statistically compared.

Results: In general, participants significantly preferred (p<0.0001) an endo-perio combined treatment (44.7%), or extraction (31%) over endodontic therapy. Only 18% of participants would refer the patient to an endodontist or perform root canal therapy. Patient/tooth-related factors did not influence treatment-planning decisions.

Conclusions: Endodontic lesions with a radiographic “J” or “halo” shape were commonly misdiagnosed as endo-perio lesions and endo-perio combined treatment or extraction was often recommended as the treatment of choice.

Clinical significance: A very high percentage of teeth with “J-shaped” radiographic lesions do not have a vertical root fracture or an endo-perio lesion, so an endo-perio combined treatment or extraction should not be the treatment of choice in these cases.

Introduction

The relationship between the attachment apparatus and the root canal system has been widely documented and classified (Simon et al. 2013, Harrington 1979). In most cases, periradicular pathosis occurs apically and can be easily distinguished from endo-perio or periodontal pathosis. In order for a draining sinus tract (DST) that drains close to the apex to develop, cortical fenestration has been reported to be fundamental (Jalali et al. 2019, See et al. 2019). As microbial products from infected pulp tissue diffuse to the periodontal tissues through furcal lateral and accessory canals alongside the root, they often cause periradicular inflammation that is indistinguishable from periodontal disease because these lesions may expand horizontally initially, but then proceed vertically (Yamasaki et al. 1994, Vera et al. 2006). These lesions may traverse a pathway through the periodontal ligament, or drain subperiosteally to the osseous crest and from there to the gingival sulcus (Kelly & Ellinger 1988). Because bone resorption occurs, clinical and radiographical distinction between a periodontal and an endodontic lesion may be difficult because the gingival/furcal/sulcular DST usually allows penetration of the periodontal probe in a localized area, in the same way as in a periodontal pocket caused by a crack extending into the root or a vertical root fracture (VRF), but in the case of a DST, the periodontal ligament usually remains intact and inserted to the radicular cementum (Seltzer et al. 1967, Simring & Goldberg 1964, Rotstein & Simon 2006).

Clinicians have also learned that a combination that includes a deep periodontal pocket, a sinus tract and a “J-shaped” or “halo” radiographic feature or 3D low-density area is usually pathognomonic for a VRF where extraction is the treatment of choice. At best, a diagnosis of an endo-perio lesion requiring endodontic and periodontal treatment is often recommended when extraction is not the treatment option or when there is any doubt that the root is fractured. Whether this combination of signs and symptoms can be readily considered as pathognomonic for a VRF is questionable (Kasahara et al. 2020, Rivera & Walton 2008) because some symptoms such as pain during mastication, and signs including gingival DSTs, lateral and furcal radiolucencies and even tooth mobility could also be caused by apical periodontitis in cases of endodontic or persistent disease (Walton 2017, Tamse et al. 1999).

If these “false periodontal pockets” were correctly diagnosed as DSTs, then the healing rate would be well over 70% if non-surgical root canal treatment was performed adequately, as it is for most DSTs draining close to the apical area (Artaza et al. 2021). Because of the confusion arising from sulcular DSTs and “J-shaped” or “halo” lesions, the objective of the present study was to assess the treatment plan that would be recommended by general dentists/practitioners and specialists from disciplines other than endodontics in cases that have a radiographic or tomographic appearance of a “J-Shaped” or “halo” lesion, with an isolated penetration of the periodontal probe of > 5 mm and a diagnosis of pulp necrosis or a previously-treated tooth, and the influence of patient and tooth-related factors in treatment decision planning.

Materials and methods

The experimental design was independently reviewed and approved by the university institutional ethics board. Written informed consent was obtained from the evaluators prior to answering the questionnaire.

Case selection

Fifteen teeth that preoperatively presented with a distinct radiographic/3D appearance of a “J-shaped” or “halo” lesion and a probing depth of > 5 mm at one surface/site were selected for the study. The radiographic lesion also involved the furcation area in molars. Only teeth for which the grade of Miller class mobility Class I (Mobility greater than physiologic) or Class II (Tooth can be moved up to 1mm or more in a lateral direction (buccolingual or mesiodistal and inability to depress the tooth in an apicocoronal direction) was registered in the patients’ clinical records were included.

All 15 selected teeth were previously treated by four endodontists with between 15 and 28 years of clinical experience (19.5 years on average).

Treatment performed was either non-surgical root canal treatment/retreatment (NSRCT: n = 13) or surgical root canal retreatment (SRCT: n = 2), but in no case was any periodontal treatment or grafting performed. None of the treated teeth presented a crack or a radicular fracture when inspected microscopically. All teeth had a pulp diagnosis of a necrotic pulp or a previously treated tooth and a periapical diagnosis of chronic apical abscess. All teeth were endodontically treated and follow-up appointments were carried out between 7 and 14 days to assess reversal of symptoms and to ensure that the sinus tracts were no longer draining. Then, all 15 cases were controlled with follow-up evaluations and considered healed radiographically/tomographically as well as clinically after periods between 1 and 6 years, (average time 3 years and 4 months).

Presentation of the cases to the evaluators

Evaluations were carried out during the COVID pandemic (2020-2021) via zoom by practitioners (evaluators) willing to participate and after they downloaded the Slido Platform (app.sli.do (Cisco Systems, San Jose, CA, USA) onto their smartphones. None of the clinicians who had treated the cases were evaluators

Preoperative radiographs and 3D images along with the clinical test data and probing depth measurements were provided to the evaluators including information regarding the pulpal diagnosis of either a necrotic pulp or previously treated tooth. No periapical diagnosis was provided to them. Cases were presented as a Powerpoint, Keynote or PDF presentation, and no postoperative data or images were included. All personal data from the patients was excluded except for age and systemic diseases when applicable, and the evaluators were asked to choose from one of four options regarding the treatment plan they would offer to the patient. The treatment options were: a) extract and replace the tooth, b) refer to an endodontist or perform root canal therapy, c) refer to a periodontist or perform periodontal treatment, and d) perform or refer for endo-perio treatment.

After each case was presented (Figure 1), respondents/evaluators were asked to choose one of the four options or none in cases where they were unsure or thought the information was inadequate for them to suggest a treatment plan. Graphics with the answers displayed in the Slido application after each case were recorded.

Statistical Analysis

Descriptive and inferential statistics were calculated using SPSS software 25.0 (IBM Corp., Armonk, NY, USA). In a first statistical analysis, the treatment options selected for each specific case were compared using a one-sample Chi-square test. In a second analysis, a multivariate logistic regression analysis was used to understand whether the tooth position (anterior/posterior), tooth mobility status or the age of the patient influenced the primary treatment option selected for each specific case.

Results

The number of responses varied for each specific case. Table 1 shows preoperative data for each case and the percentage of participants selecting the different treatment options for each specific case. Table 2 shows a summary of the number of responses obtained for each specific case, as well as counts of respondents per dental specialty and gender.

In general, the treatment option most frequently selected was endo-perio combined treatment (44.7 %), followed by tooth extraction and replacement (31%).The least selected option was the referral to a periodontist or exclusive periodontal treatment (6.3%). Only 18% of participants would refer the patient to an endodontist or perform root canal therapy.

Specifically, participants preferred endo-perio combined treatment instead of endodontic therapy in cases 1, 3, 4, 6, 8, 9, 10, 11 and 15. Likewise, in cases 2, 5, 7, 12, 13 and 14 participants significantly preferred extraction of the tooth. These treatment options were significantly preferred when compared with the treatment option of choice “refer to an endodontist or perform root canal therapy” (p < 0.0001). None of the cases showed a majority of participants selecting the treatment option of referring the patient to an endodontist or performing root canal therapy.

Table 1 shows the high percentage of respondents opting to carry out both endodontic and periodontal treatment or to extract and replace the tooth. Some examples of cases used in the survey and the treatment option selected are shown in Figure 1.

Neither the position of the tooth, age of the patient nor the tooth mobility status influenced the primary treatment option selected by a higher number of participants. There were no significant differences in any of these parameters when the extraction of the tooth was the primary option selected instead of any other treatment option that would have preserved the tooth (p > 0.05).

Discussion

The objective of the present study was to determine the treatment plan that is commonly offered to patients when a “J-” or “halo”-shaped lesion is observed on a radiograph or 3D image and which in the case of molars involves the furcation. Clinical data included probe penetration > 5 mm in an isolated site and grade 0 to 2 Miller mobility. The 15 cases had previously been endodontically treated (without any type of periodontal treatment) by endodontic specialists in private practice, and all of them had a periapical diagnosis of a chronic alveolar abscess, where the DST drained gingivally. Subsequent follow-up showed that all 15 cases had adequately repaired radiographically/tomographically with no data or clinical signs of a DST, pain, inflammation, or periodontal probing of more than 3 mm.

The most common response given by the evaluators as the treatment of choice to be performed was endo-periodontal treatment followed by extraction and replacement by an implant. The answers are not surprising because usually during dental training, it is taught that the presence of a “J-shaped” or “halo” lesion or a radiolucent lesion in the furcation of a posterior tooth indicates that the problem is usually periodontal, or endo-perio and often caused by a VRF, especially but not limited to endodontically-treated teeth. However, offering a treatment plan based on radiographs or 3D images without a careful clinical examination and inter-consultation can and often does result in errors leading to overtreatment or extraction of teeth that could be otherwise successfully endodontically treated.

At the same time, the app used to collect the responses of participants only allowed to retrieve summaries of data for each specific case and treatment option. Unfortunately, this type of data did not allow to use a more complex statistical analysis that would have correlated the responses with demographic characteristics of the participants. Still, the information retrieved was very useful to understand that there is a general confusion in the treatment plan of choice for “J-shaped” or “halo” lesions of endodontic origin.

At the same time, another limitation of the present study is that the number of respondents varied greatly among the 15 clinical cases. Some clinical cases might have been controversial for some of the participants that preferred to abstain for voting a specific treatment plan. This assumption also may relate to the fact that the diagnosis and treatment planning for some specific clinical cases presenting “J-shaped” or “halo” lesions are challenging for some clinicians.

Some differences exist between endodontic and periodontal bone loss. In endodontic lesions, a single-narrow pocket or “false pocket” is usually a sinus tract, while in periodontal disease, periodontal pockets are usually wide coronally and generalized. Despite these differences, a combination of a deep pocket and a sinus tract, when present in an endodontically treated tooth, has been related to the presence of a VRF (Suebnukarn et al. 2010). A recent study evaluated the correlation between the clinical signs that have been considered as pathognomonic for the diagnosis of a VRF and the true confirmation of it being present (Goldberger et al. 2021). Verification of the VRF was performed after either extraction or surgical exploration, and it was found that the correlation and the reference standard is low, because only 28% of teeth with sinus tracts and deep periodontal pockets were confirmed to have a VRF (Goldberger et al. 2021).

The “halo” or “J- shaped” radiographic lesion is also usually associated with VRFs (Tamse et al. 1999), but in reality a VRF was found to be present in less than half of the cases (44%) (Goldberger et al. 2021).

These lesions appear to develop in the absence of root fractures when there are thick cortical bone plates and a periapical lesion has become a periradicular one by spreading vertically and parallel to the longitudinal axis of the root reaching the coronal third and/or the furcation area (Figure 2) (Yamasaki et al. 1994, Kelly & Ellinger 1988). However, these should be considered and diagnosed as endodontic lesions even when they have the radiographic/tomographic appearance of a periodontal lesion. Generally, although they cause bone resorption, the periodontal ligament is usually not involved or affected and the attachment apparatus is not destroyed, as it would be in a periodontal lesion (Kelly & Ellinger 1988, Rotstein & Simon 2006).

The present study combined the use of periapical radiographs and CBCT images. The use of CBCT 3D imaging provided better but not definite information regarding patterns of bone loss which, once corroborated by an accurate clinical evaluation, should allow the trained clinician to arrive at a differential diagnosis between a VRF causing periodontal disease, periodontal disease without a vertically fractured root, and endodontic disease with a gingival DST (Special Committee to Revise the Joint AAE/AAOMR Position Statement on use of CBCT in Endodontics 2015, Bueno et al. 2021, Fayad et al. 2012, Quintero-Álvarez et al. 2021).

Evaluators were not obliged to answer in all the cases; they voluntarily decided when to respond. A small percentage of evaluators decided not to answer some of the questions, probably because they were not sure if they had enough data to recommend a treatment plan or were unsure as to the proper periapical-periradicular diagnosis and treatment plan.

Only 18% of the evaluators answered that an endodontic treatment would be sufficient to achieve the repair of the endodontic lesion, which in the 15 cases and as demonstrated in the postoperative controls, should have been the proposed treatment of choice in all cases presented to the evaluators (Figure 3).

A “J-shaped” or “halo” lesion can be of endodontic origin when there is infection in the root canal system and the endodontic lesion spreads vertically or pus drains through the attachment apparatus creating a precipitous drop in probe depth around a tooth limited to one site and where mobility is usually absent (Jivoinovici et al. 2014). Understanding this endodontic etiology should guide the practitioner to perform NSRCT and to avoid any type of periodontal therapy or extraction (Jansson et al. 1993, Zehnder et al. 2002, Harrington 1979, Vera et al. 2006, Burns et al. 2018).

From the present study we concluded that there was confusion when evaluating possible radiographic and tomographic aspects of apical periodontitis, and that this may influence clinicians to make erroneous clinical decisions that include extraction, solely based on an isolated drop in probing depth and a radiographic or 3D “J-shaped” or “halo” lesion. It is also recommended that when observing these types of lesions, endodontic consultation should be requested in order to avoid over treatment or extraction of the tooth.