External cervical resorption: an analysis using cone beam and microfocus computed tomography and scanning electron microscopy

Exceptional bone remodeling over composite restoration in the management of external root resorption: A case report

A 65-year-old Caucasian male was referred to an endodontic specialist practice in a private clinic in December 2019 for the management of an asymptomatic, radiolucent lesion located at the cervical level of the distal root of his right lower first molar, noticed during a routine periapical radiograph. After an accurate evaluation with cone-beam computed tomography (CBCT), the subgingival lesion was diagnosed as a supracrestal external cervical resorption (ECR), with a circumferential spread ⩽90°, confined to dentine without pulp involvement. The lesion was treated with the following sequence: (1) a full flap accessed the ECR, (2) the granulomatous tissue was removed from the root area, (3) the cavity was refreshed and filled with a well-refined and polished resin composite, (4) the flap was sutured at the cemento-enamel junction. A mandibular CBCT scan was performed before treatment, right after treatment, and 3 years postoperatively. Compared to the 3-year posttreatment CBCT scan, the immediate posttreatment one, revealed the absence of bone loss and an unexpected coronal bone remodeling with new bone formation over the treated lesion.

Clinical management of external cervical resorption: A systematic review

This review investigated whether any therapeutic options influenced the outcome of treatment for teeth with external cervical resorption. Out of 870 articles identified by an electronic search, 60 clinical case reports and six case series were included. No randomised clinical trials were found. Risk of bias was assessed using Joanna Briggs Institute's tools. External surgical intervention was the preferred method of accessing the lesions. Removal of resorptive tissue was most often achieved mechanically. Bioactive endodontic cements were the preferred materials for restoring teeth. The outcome measures were based on clinical and radiographic parameters. Of the cases included in the review, no specific treatment approach had a superior outcome in relation to Heithersay's classification. Furthermore, due to the absence of randomised clinical trials, and the low level of evidence associated with case reports/case series, it was not possible to define the optimum clinical treatment for external cervical resorption.

Clinical and radiographic features of external cervical resorption - An observational study

AIM

To determine the prevalence of symptoms, clinical signs and radiographic presentation of external cervical resorption (ECR).

METHODOLOGY

This study involved 215 ECR lesions in 194 patients referred to the Endodontic postgraduate Unit at King's College London or Specialist Endodontic practice (London, UK). The clinical and radiographic findings (periapical [PA] and cone beam computed tomography [CBCT]) were readily accessible for evaluation. A checklist was used for data collection. Inferential analysis was carried out to determine if there was any potential association between type and location of tooth in the jaw as well as sex, age of the patient and ECR presentation and radiographic feature.

RESULTS

Eighty-eight patients (94 teeth) were female and 106 patients were male (121 teeth), the mean age (±SD) was 41.5 (±17.7) years. Fifteen patients (7.7%) had more than one ECR lesion. The most affected teeth were maxillary central incisors (21.4% [46 teeth]) and mandibular first molars (10.2% [22 teeth]). ECR was most commonly detected as an incidental radiographic finding in 58.1% [125 teeth] of the cases. ECR presented with symptoms of pulpal/periapical disease in 23.3% [n = 50] and clinical signs (e.g. pink spot, cavitation) in 16.7% [36 teeth] of the cases. Clinical signs such as cavitation (14%), pink spot (5.1%) and discolouration (2.8%) were uncommon, but their incidence increased up to 24.7% when combined with other clinical findings. ECR was detected in the resorptive and reparative phases in 70.2% and 29.8% of the cases respectively.

CONCLUSION

ECR appears to be quiescent in nature, the majority being asymptomatic and diagnosed incidentally from PA or CBCT. When assessed with the Patel classification, most lesions were minimal to moderate in relation to their height (1 or 2) and circumferential spread (A or B). However, the majority of ECRs were in (close) proximity to the pulp. Symptoms and clinical signs were associated with (probable) pulp involvement rather than the height and circumferential spread of the lesion. Clinical signs were more frequently associated when ECR affected multiple surfaces.

Repair of an Extensive External Cervical Resorption Lesion Using Intentional Replantation with Crown Rotation

Treatment of large external cervical resorption (ECR) lesions may be compromised, rendering the tooth unrestorable. Intentional replantation is a potential treatment option depending on the site and extent of ECR. We present a case of a large ECR successfully managed with intentional replantation with rotation of the tooth. The female patient consulted the hospital clinic, with an extensive palatal ECR on the maxillary lateral incisor. Routine planar radiographs and cone-beam computed tomography demonstrated a larger palatal than the ECR lesion (Heithersay Class III and Patel's Class 2Bp) not amenable to nonsurgical treatment. Intentional replantation after short-term extrusion was planned. The defect was restored, then a palatal ferrule was achieved by rotating the tooth by 180°. At the 18-month follow-up, the periradicular and periodontal tissues remained healthy, and no other symptoms were reported. In conclusion, this successful video-illustrated clinical case highlights the benefits of intentional replantation in saving teeth with advanced ECR.

External Cervical Resorption: Relationships Between Classification, Treatment, and One-Year Outcome with Evaluation of the Heithersay and Patel Classification Systems

INTRO

The purpose of this study was to identify possible associations between classification, treatment, and one-year outcome of external cervical resorption (ECR) lesions using the Heithersay and Patel systems. Performance of the Patel 3-dimensional classification system was also evaluated.

METHODS

A chart review identified 142 cases of ECR over a twelve-year period. Information regarding demographics, predisposing factors, lesion classification, treatment, and outcomes were collected and analyzed. Inter- and intra-observer reliability analyses were conducted for both classification systems.

RESULTS

There were 72 cases with at least one year of follow up. 70% of these cases survived. Treatment recommendations were correlated with both Heithersay and Patel classification. There were no correlations found between one-year outcome and either classification or treatment done. The weighted reliability analysis showed substantial agreement in both classification systems for both inter- and intra-observer agreement. There was a significant association between the two systems, however the Heithersay system tended to underestimate the apical extent of the lesion.

CONCLUSIONS

Periodic review of ECR lesions presents as a viable treatment option, at least for one year after diagnosis. The Patel 3-D classification system is at least as effective as the Heithersay system and should be used in future ECR prognosis studies. Further long-term outcome assessments are still needed.

Early detection of external cervical resorption in posterior teeth: a radiographic, cross-sectional study of an adolescent population

OBJECTIVES

To establish the prevalence and severity of external cervical resorption (ECR) in posterior teeth observed in bitewing (BW) radiographs in an epidemiological study of a 17-year-old patient population from community dentistry. Furthermore, to assess the potential predisposing factors for ECR.

METHODS

Posterior BWs from 5596 patients (2717 females, 2879 males; mean age 17.8 years) were assessed by three observers in order to detect ECR (using Heithersay's classification system, severity classes 1-4). When ECR was suspected, cone beam CT (CBCT) was offered to verify diagnosis. Prevalence was estimated based on ECR suspected in BWs and finally in CBCT. Possible predisposing factors (orthodontic treatment, trauma, and periodontal disease) were recorded and assessed for association with ECR.

RESULTS

In 41 patients, ECR was suspected in BWs (suspected prevalence 0.73%). 32 patients accepted CBCT examination, of which eight were verified to have ECR (final prevalence 0.18%). In 24 patients, other disease entities and abnormal tooth morphology, that had mimicked ECR in BWs, excluded ECR in CBCT. ECR severity ranged from class 1-3 in BW and 2-4 in CBCT. All but one case had not been diagnosed by the patient's community dentist. No statistically significant association between predisposing factors and ECR was identified.

CONCLUSIONS

ECR had low prevalence in this adolescent population, as observed in both BWs and CBCT. Still, early detection of ECR is important for treatment prognosis, and attention should be paid to this disease entity when assessing BWs obtained for other diagnostic purposes. CBCT may subsequently aid in verifying the disease.

Present status and future directions: Root resorption

Root resorption is the loss of dental hard tissue because of odontoclastic action. In permanent teeth, it is undesirable and pathological in nature. Root resorption may occur on the inner aspect of the root canal (internal root resorption) or on the outer aspect of the root (external root resorption). Regardless of its location, root resorption is irreversible, and may result in discomfort for the patient, requires management and/or, in some cases, results in the premature loss of the affected tooth. Root resorption is often challenging to accurately diagnose and manage. The aim of this narrative review is to present the relevant literature on the aetiology, pathogenesis, diagnosis and management, as well as discuss the future directions of diagnosis and management of root resorption.

Tooth root resorption: A review

Tooth root resorption is multifactorial, leading to progressive destruction and eventual loss of tooth root dentin and cement. There are internal and external types of root resorption, each having its variety. The etiology and pathogenesis of tooth root resorption are poorly understood, and the most significant etiological factors are trauma, pulpal infection, tooth bleaching, and orthodontic treatment. Tooth root resorption is primarily asymptomatic; thus, it is revealed accidentally by radiographic examination. Progressive clinical manifestations are pain, tooth discoloration, tooth mobility, and other conditions. Awareness of the causes and risk factors allowing tooth root resorption, and regular radiographic examination, in case of necessity, make it possible to reveal resorption at an early stage and to prevent its further development. Thus, the aim of this study is to present etiopathogenesis, a clinical course, and diagnostic peculiarities of internal and external types of tooth root resorption, enabling practicing dentists to timely diagnose root resorption and take appropriate measures to avoid further complications. Within the limitation of this review, even though the etiopathogenesis of tooth root resorption is yet not fully understood, it is suggested that the etiological factors fall into two groups (endogenic and exogenic) to enhance further understanding of the possible causes and mechanisms of root resorption and allow practitioners to monitor high-risk patients and make timely diagnoses. Moreover, radiographic examination and CBCT are indispensable for the diagnosis of root resorption.

A clinical approach strategy for the diagnosis, treatment and evaluation of external cervical resorption

AIM

To propose a clinical approach strategy on the diagnosis, treatment, and evaluation of external cervical tooth resorption (ECR) cases. To investigate and discuss the outcome of this approach.

METHODOLOGY

A clinical approach strategy on ECR was developed based on a retrospective observation study of 542 teeth. 47 teeth were excluded due to lack of clinical/radiographical information, and 182 were immediately extracted. This approach had three steps: diagnosis, treatment planning, and evaluation. During diagnosis, the medical, dental history and clinical/radiographical characteristics were evaluated. Depending on the resorption extent, ECR cases were categorized into four classes according to Heithersay's classification. During treatment planning, a treatment decision flowchart was prepared based on four main decisive criteria: probing feasibility, pain, location and extent of resorption (class), and existence of bonelike tissue. Three treatment options were applied: a) extraction, b) monitoring, or c) conservative treatment by external, internal, or combination of internal-external treatments. During evaluation, assessment of ECR progression, tooth survival and other factors like esthetics and periodontal attachment were performed. Descriptive statistical analysis of the outcome for up to ten years (for the overall clinical approach and for each individual treatment decision), was carried out with OriginLabs OriginPro 9 and Microsoft Excel 365.

RESULTS

A three-step strategy was developed on how to deal with ECR cases. Indicative examples of each treatment decision were presented and discussed. The overall survival rate of this strategy was 84.6% (3 years), 70.3% (5 years), 42.7% (8 years) and 28.6% (10 years). Higher survival rate was observed for external treatment decision than for internal. The success of each treatment decision depended on the extent of the resorption (class). The success of a treatment decision should be based on the long-term outcome, as a different evolution can be observed with time.

CONCLUSIONS

A clinical approach strategy was introduced on ECR pathosis. This strategy was not solely based on ECR class, as other important decisive criteria were considered. This step-wise approach, has a 70.3% survival rate with a mean of 5 years. This work will hopefully provide an incentive for a broader collaboration, to potentially establish a universally accepted ECR treatment strategy.

External cervical resorption: Radiological diagnosis and literature (Review)

External cervical resorption (ECR) is a relatively unknown and insidious pathology characterized by the loss of hard dental tissues such as: Enamel, cementum and dentine due to clastic function. It begins as a localized resorptive process that initiates on the area of the root beneath the epithelial attachment and the coronal part of the alveolar process, involving vital and non-vital tissues. Despite the fact that there are several potential predisposing factors related to ECR, its aetiology still remains poorly understood and more research is needed to establish the cause-and-effect relationship of all the etiological factors. Improved radiographic detection using cone-beam computed tomography (CBCT) is required in order to correctly classify and assess this entity. This provides a three-dimensional insight into the lesion, regarding the location, the size, the depth and the circumferential spread of the ECR defect. It also allows establishment of the most efficacious treatment plan and management. The purpose of this literature review is to cover the relevant literature concerning the etiology, pathogenesis, clinical and radiological presentation and management of ECRs (based on the CBCT findings).

The Disease Process, Diagnosis and Treatment of Invasive Cervical Resorption: A Review

Invasive cervical resorption (ICR) is a localized, subepithelial, supra-osseous resorptive process of the tooth. Although there are several predisposing factors associated with ICR, its etiology and pathogenesis are poorly understood. The damage to the protective layer on the external root surface appears to allow for the attachment of clastic cells and initiate the resorptive process, which is confined by the inner protective pericanalar resorption-resistant sheet surrounding the root canal space. The use of cone-beam computed tomography (CBCT) is recommended for the diagnosis and assessment of a resorptive lesion. Based on the thorough evaluation of the size and location of the ICR lesion using CBCT, surgical or nonsurgical treatment can be chosen to address the source of the resorption. This review discusses the current status of knowledge regarding the biology of ICR lesions as well as their external or internal treatment using hydraulic calcium silicate-based materials. Future clinical outcome studies are necessary to evaluate the impact of hydraulic calcium silicate-based materials on the healing of ICR lesions.

Multiple idiopathic cervical root resorption involving all permanent teeth

Multiple idiopathic external cervical root resorption is a rare condition with numerous predisposing factors that have not yet been clearly elucidated. In addition, its diagnosis and treatment pose challenges for clinicians, and thus, the extraction of the involved teeth is commonly performed. Here, we report a 29-year-old pregnant woman with no contributory medical or family/social history who experienced cervical root resorption that progressed aggressively and involved all permanent teeth. This case is unique owing to the involvement of all teeth. Reports of multiple idiopathic external cervical root resorption are rare in the literature, and the pathogenesis of the condition is poorly understood. This report aims to add an additional case to the existing literature, analyse the underlying mechanisms and provide clinicians with some guidance in diagnosing cervical root resorption.

Palatogingival groove and root canal instrumentation

AIM

To evaluate the morphology and impact of root canal preparation in maxillary incisors with palatogingival grooves (PGG).

METHODOLOGY

Twenty extracted human maxillary incisors with PGG were subjected to macroscopic analysis and scanning electron microscopy analysis (SEM). The following characteristics of the PGG were evaluated: depth, point of origin in the cingulum, extension and position on the lingual surface. Furthermore, the presence of calculus, communications between the root canal system and the PGG, and root resorptions were investigated. The root canals were subsequently instrumented with K-files of three consecutive sizes. The teeth were sectioned, and the axial plane of each tooth section was imaged using SEM before and after instrumentation. The distance between the root canal walls and the PGG was calculated according to the location. Additionally, the distance between canal walls and cementum was measured at three different sites, to verify if instrumentation influenced dentine removal on a specific wall in teeth with PGG. Statistical analysis was performed using the Mann-Whitney or Student's t-test (P < 0.05).

RESULTS

Macroscopic analysis revealed that a deep groove was most frequently observed (75%), followed by a depression/shallow groove (25%) (P < 0.05). PGG typically originated in the distal margin ridge of the cingulum (65%) (P < 0.05), extending only to the middle (45%) or up to the apical (50%) third of the root (P < 0.05). Additionally, PGGs were typically located on the distal aspect of the lingual surface (70%) (P < 0.05). Calculus was concentrated on the surface of the crown and cementum-enamel junction (P < 0.05). Communication between the root canal and PGG was present in 35% of teeth, and root resorptions were noted in 50% of teeth. The distance between the external root surface and the pulp cavity was significantly narrower after instrumentation (P < 0.05); however, root canal preparation did not influence dentine removal on the specific wall associated with the groove (P > 0.05).

CONCLUSIONS

Palatogingival grooves were characteristically deep and originated from the distal margin of the cingulum. Although it has been associated with a thinner root wall, root canal preparation did not influence the thickness of the specific wall in the maxillary incisors with PGG.

The ins and outs of root resorption

Root resorption is a poorly understood phenomenon and is often misdiagnosed and, as a result, inappropriately treated. The aim of this paper is to provide a practical guide for diagnosis of root resorption lesions using a simple classification, and to describe the principles of management of these resorptive defects in everyday practice.

Cone beam computed tomography in Endodontics - a review of the literature

The use of cone beam computed tomography (CBCT) in the diagnosis and/or management of endodontic problems is increasing and is reflected in the exponential rise in publications on this topic in the last two decades. The aim of this paper is to: (i) Review current literature on the endodontic applications of CBCT; (ii) Based on current evidence make recommendations for the use of CBCT in Endodontics; (iii) Highlight the areas in which more research is required.

External cervical resorption-part 1: histopathology, distribution and presentation

External cervical resorption (ECR) is the loss of dental hard tissue as a result of odontoclastic action. It is a dynamic process that involves periodontal, dental and in later stages pulpal tissues. Over the last two decades, ECR has attracted increased interest; this is in part due to novel micro-CT and histopathological techniques for its assessment and also improved radiographic detection using CBCT. This literature review will cover the aetiology, potential predisposing factors, histopathology and diagnosis of ECR. Part 2 will cover the management of ECR.

Descriptive Analysis of Factors Associated with External Cervical Resorption

INTRODUCTION

The aim of this study was to perform a descriptive analysis of the occurrence of external cervical resorption (ECR) in relation to the patients' characteristics (sex, age, and tooth type) and the potentially involved predisposing factors.

METHODS

This study includes data on 284 patients (337 teeth with evidence of ECR) referred to the University Hospital Leuven (Leuven, Belgium) and Endo Rotterdam (Rotterdam, the Netherlands) for diagnosis and treatment from 2010 to 2015. The medical history, existing radiographs, and dental records were available for evaluation. Each patient was then interviewed followed by a thorough clinical and radiographic examination. Intraoral pictures using a dental operating microscope and digital camera were taken during clinical examination. The radiographic examination consisted of digital periapical radiography and/or cone-beam computed tomographic imaging. A review of existing literature provided a potential predisposing factor checklist for ECR. The clinical data were correlated with the dental and medical history of each patient in an attempt to identify some potential predisposing factor(s) that could contribute to ECR. The frequency of the occurrence of ECR was correlated with tooth type, sex and age of the patient, and each 1 of the recorded potential predisposing factor(s).

RESULTS

From the examined teeth (337) with ECR, 175 (54%) were found in male patients and 162 (46%) were found in female patients. In 59% of the cases, more than 1 potential predisposing factor was identified. Most ECR cases were observed on maxillary central incisors (29%) followed by maxillary canines (14%), mandibular molars (14%), and maxillary premolars (11%). In addition, most ECR cases were observed on maxillary teeth (72%). The most frequently appearing factor was orthodontics (45.7%). Other frequently observed factors were trauma (28.5%), parafunctional habits (23.2%), poor oral health (22.9%), malocclusion (17.5%), and extraction of a neighboring tooth (14%).

CONCLUSIONS

The data indicate that ECR is not related to patient sex. ECR occurs most often in the maxillary central incisor. In the majority of the cases, more than 1 potential predisposing factor was identified, indicating that ECR may be mainly multifactorial. The most frequently appearing factors were orthodontics, iatrogenic or accidental trauma, and poor oral health. This information may be helpful in diagnosing ECR at an early stage when screening patients presenting with these predisposing factors.

Three-dimensional characterization of root morphology for maxillary incisors

The aim of this study was to test the reproducibility of three-dimensional (3D) surface models of maxillary incisors and to propose a characterization of root morphology. The sample was comprised of pre-treatment cone-beam computed tomography (CBCT) images of fifty-five patients. The CBCTs were used to construct 3D surface models of the maxillary incisors. The reproducibility of surface models was tested by repeated construction of them by two observers. A 3D surface model that corresponded to the average of all lateral and all central incisors was generated. 3D surface distances and vector differences were calculated for each individual tooth and the average of the teeth considered. The corresponding points on the 3D surface mesh for each subgroup were compared statistically to those of the neutral subgroup using shape analysis MANCOVA and Hotelling's t-statistic (p < 0.05). Repeated construction of surface models demonstrated adequate inter-rater reproducibility. The distribution of 3D models into root morphology subgroups was: blunt (11% and 26% of the central and lateral incisors, respectively), conical (15% of the central incisors), long (27% and 20% of the central and lateral incisors, respectively), and short (15% and 4% of the central and lateral incisors, respectively). Compared to the neutral average, statistically significant differences in root morphology were found for blunt, long, conical, and short central incisors and for blunt, long, and short lateral incisors. We can conclude that 3D surface models construction for upper incisors is reproducible. 3D shape analysis using CBCT images allows a phenotypic characterization of incisor root morphology.

The Use of Intentional Replantation to Repair an External Cervical Resorptive Lesion Not Amenable to Conventional Surgical Repair

Intentional replantation consists of purposefully extracting a tooth, correcting the defect and replanting it into its original socket. This case report describes how this technique was used to successfully restore an external cervical resorptive (ECR) lesion. A 22-year-old man was diagnosed with ECR of the mandibular right canine following clinical and radiographic examination. CBCT showed the lesion had been initiated distally and extended circumferentially around the root canal. The nature of the resorptive lesion meant that it was inaccessible to repair conventionally in a predictable manner. This report describes how intentional replantation was used to access and restore the lesion with minimal patient cooperation and postoperative discomfort. At an 18-month recall the tooth was clinically sound with no radiographic evidence of inflammatory or replacement root resorption. Intentional replantation should be considered a viable treatment option when ECR is inaccessible and cannot be restored using conventional techniques.

A novel multimodular methodology to investigate external cervical tooth resorption

AIM

To introduce a multimodular combination of techniques as a novel minimal invasive approach to investigate efficiently and accurately external cervical resorption (ECR).

METHODOLOGY

One case of a central incisor with extensive external cervical resorption was selected to demonstrate the potential of a comparative novel study methodology. ECR diagnosis was based on clinical inspection, digital radiography and cone-beam computed tomography (CBCT). After extraction, the tooth was investigated using microfocus computed tomography (micro-CT), nano-CT and hard tissue histology. These techniques were compared for their accuracy and applicability to highlight their advantages and disadvantages.

RESULTS

Nano-CT was more effective than micro-CT and CBCT for detailed ex vivo exploration of ECR. The reparative tissue, pericanalar resorption resistant sheet (PRRS), pulp tissue reactions, resorption channels and their interconnection with the periodontal ligament space were accurately visualized by detailed processing and analysis of the nano-CT data set with Dataviewer and CTAn software. Nano-CT analysis provided better insight in the true extent of the resorption, based on quantitative measurements and 3D visualization of the tooth structure. Nano-CT imaging results were similar to hard tissue histology at the mineralized tissue level. To clarify the dynamic phenomenon of reparative tissue formation and substitution of the resorbed tissues, nano-CT needed to be associated with hard tissue histology.

CONCLUSION

Nano-CT is a fast and minimal invasive technique for the ex vivo analysis and understanding of ECR and is complementary with hard tissue histology. A combined approach of clinical and CBCT examination, with nano-CT and histological mapping measurements, can provide an ideal platform for future ECR imaging and exploration studies.

Detection of Apical Inflammatory Root Resorption Associated with Periapical Lesion Using Different Methods

The aim of this study was to detect apical inflammatory root resorption (AIRR) associated with periapical lesion using cone beam computed tomography (CBCT) and scanning electronic microscopy (SEM). This clinical study evaluated AIRR in 88 root apexes, from 52 permanent teeth of 14 patients, extracted for different reasons. The patients were submitted to a clinical interview, review of dental/medical histories and clinical/imaging examinations for treatment planning. All selected teeth showed unrestorable condition because of the extensive coronal breakdown due to carious lesions, and root canal infection associated with periapical lesions. CBCT images were obtained from the patients with the aim of diagnosing the periapical diseases which showed complex or doubtful conditions. Two examiners assessed the presence or absence of AIRR. Apices were also analyzed under SEM. Chi-square test was used to compare the imaging methods for detection of AIRR. The level of statistical significance was set at 5%. AIRR associated with root canal infection and apical periodontitis was found in 61.4% of the cases studied by using SEM, and at least half of the cases by CBCT. The microscopic analysis remains as a reference standard against the imaging method to identify AIRR.