A Volumetric Assessment of External Cervical Resorption Cases and Its Correlation to Classification, Treatment Planning, and Expected Prognosis

Long-term prognosis for teeth with external cervical resorption based on periapical images and cone beam CT: A clinical study

AIM

To evaluate whether supplemental information from CBCT changed long-term prognosis for teeth with external cervical resorption (ECR) compared to periapical (PA) images. Furthermore, to assess predictive findings in PA images and evaluate which findings in CBCT affected the long-term prognosis of teeth with ECR.

METHODOLOGY

One hundred and ninty-four patients, mean age 41.2, range 13-81, having 244 teeth with ECR were included. An initial long-term prognosis determined either good or poor was established based on intraoral images. Afterwards, the patients underwent CBCT, and final long-term prognosis was decided. From the PA images and CBCT, ECR using Heithersay's classification system, pulp involvement and extension of ECR was assessed. In CBCT, the number of surface lesion(s) was additionally assessed. Descriptive statistics evaluated changes in long-term prognosis after CBCT. Logistic regression analyses tested if findings in PA images and CBCT affected the long-term prognosis.

RESULTS

Based on CBCT, out of 244 teeth the long-term prognosis was assessed to be poor for 173 (70.9%) teeth and good for 71 (29.1%) teeth. The long-term prognosis changed in 76 (31.1%) teeth after CBCT; 5 (2.0%) changed from poor to good, and 71 (29%) changed from good to poor long-term prognosis. In 81 (33.2%) teeth the H-class increased, and in 10 (4.1%) teeth the H-class decreased after assessing CBCT. In 70 (28.7%) teeth, there was a change from no pulp involvement to involvement of the pulp after CBCT; eight (3.3%) teeth changed in the opposite direction. H-class 2 and 4 in PA images significantly increased the probability for a change in long-term prognosis compared to an H-class 3 (p < .05). H-class 4, pulp involvement, ECR in the oral 1/3 of the root, and more than two surface lesions seen in CBCT significantly influenced a poor long-term prognosis (p < .05).

CONCLUSIONS

Supplemental information from CBCT changed long-term prognosis in almost one third of teeth with ECR. In most cases, the long-term prognosis changed from good to poor. H-class 3 in PA images had a significant influence on change in long-term prognosis. Several findings in CBCT influenced a poor long-term prognosis.

External Cervical Resorption Detected by Cone Beam Computed Tomography on an Immature, Unerupted Maxillary Second Premolar

Root resorption is a commonly recognized risk of orthodontic treatment and can range from minimal changes at the apex to aggressive and extensive erosion of tooth structure. The following report is aimed at presenting a rare case of idiopathic aggressive preeruptive root resorption in a maxillary second premolar of a young child prior to orthodontic force. During phase I orthodontic treatment, the maxillary premolar required surgical exposure with a bracket and chain to assist in its eruption. Before the exposure, a cone beam computed tomography (CBCT) was captured to aid in localizing the premolar and its relationship to vital structures. In addition to identifying relevant anatomy, the image also revealed an incidental finding of extensive external cervical root resorption. The risks, benefits, prognosis, and alternatives of continuing with surgical exposure of the affected premolar were presented to the guardian. The informed and consented decision was made to continue with the exposure and subsequent orthodontic treatment to align the tooth in the arch. Upon eruption to the occlusal plane, the tooth was amenable to endodontic pulp vitality testing, Endo Ice, and a follow-up CBCT. It was determined that there was advanced aggressive progression of the resorptive process. The Patel Classification 3Cd/Class 4 Heithersay ECR diagnosis and a poor prognosis ultimately resulted in the extraction of the tooth. Management of this case highlights a number of important clinical features including the rarity of advanced preeruptive idiopathic external cervical root resorption, a multidisciplinary approach (orthodontic, endodontic, and surgical) to diagnose and manage the ECR, and the importance of prescribing and acquisition of appropriate imaging to aid in the early diagnosis of the entity. This case report will add to the body of knowledge of a rare incidence of advanced ECR on a young patient with a nontraumatized, unerupted maxillary second premolar.

Application of deep learning and feature selection technique on external root resorption identification on CBCT images

BACKGROUND

Artificial intelligence has been proven to improve the identification of various maxillofacial lesions. The aim of the current study is two-fold: to assess the performance of four deep learning models (DLM) in external root resorption (ERR) identification and to assess the effect of combining feature selection technique (FST) with DLM on their ability in ERR identification.

METHODS

External root resorption was simulated on 88 extracted premolar teeth using tungsten bur in different depths (0.5 mm, 1 mm, and 2 mm). All teeth were scanned using a Cone beam CT (Carestream Dental, Atlanta, GA). Afterward, a training (70%), validation (10%), and test (20%) dataset were established. The performance of four DLMs including Random Forest (RF) + Visual Geometry Group 16 (VGG), RF + EfficienNetB4 (EFNET), Support Vector Machine (SVM) + VGG, and SVM + EFNET) and four hybrid models (DLM + FST: (i) FS + RF + VGG, (ii) FS + RF + EFNET, (iii) FS + SVM + VGG and (iv) FS + SVM + EFNET) was compared. Five performance parameters were assessed: classification accuracy, F1-score, precision, specificity, and error rate. FST algorithms (Boruta and Recursive Feature Selection) were combined with the DLMs to assess their performance.

RESULTS

RF + VGG exhibited the highest performance in identifying ERR, followed by the other tested models. Similarly, FST combined with RF + VGG outperformed other models with classification accuracy, F1-score, precision, and specificity of 81.9%, weighted accuracy of 83%, and area under the curve (AUC) of 96%. Kruskal Wallis test revealed a significant difference (p = 0.008) in the prediction accuracy among the eight DLMs.

CONCLUSION

In general, all DLMs have similar performance on ERR identification. However, the performance can be improved by combining FST with DLMs.

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.

Multiple idiopathic cervical root resorption: A systematic review

The current literature on multiple idiopathic cervical root resorption (MICRR), a rare and aggressive form of external root resorption, is limited to case reports and series. Therefore, we performed a systematic review of this condition. A comprehensive search of PubMed, Embase, Web of science, Cochrane Library, CNKI, and WANFANG was conducted using key terms relevant to MICRR, supplemented by a grey literature search. Risk of bias was assessed using Cochrane's and Joanna Briggs Institute's tools. A total of 36 studies with 47 cases were included. MICRR is more common among younger females and may be related to hormonal changes and denosumab use. Initially, the premolars are usually affected but all permanent teeth may eventually be involved. Cone-beam computed tomography is recommended for diagnosis and assessment of resorptive lesions. The management is focused on complete removal and restoration of the resorptive tissue to maintain the tooth's structural integrity. However, MICRR usually has a poor prognosis. Due to its invasive and aggressive behavior, MICRR requires greater attention.

Volumetric Assessment of Apical Periodontitis Using Cone-Beam Computed Tomography-A Systematic Review

This systematic review aimed to investigate the scientific literature on volumetric studies concerning the diagnosis and treatment of apical periodontitis using CBCT. A systematic review protocol was written following the preferred reporting items for the systematic reviews and meta-analyses (PRISMA) checklist. Four electronic databases were searched for relevant publications in English, which were published up to 21 January 2023. The inclusion criteria and corresponding search keys were applied. The risk of bias was assessed using the Joanna Briggs Institute Meta-Analysis of Statistic Assessment and Review Instrument. The search strategy identified 202 studies, with 123 studies excluded during the title and abstract screening and 47 studies left for full text screening. A total of 17 studies met the inclusion criteria. The lesion volume was measured and classified according to different indices which compared the effectiveness of their diagnostics. Moreover, the volume of AP lesions increased with the thickness of the maxillary sinus mucosa in primary and secondary infections and decreased due to endodontic treatment. Volumetric measurements using CBCT are useful in the correct definition of periapical tissue pathosis using a CBCT periapical volume index and assessment of the dynamics of the treatment of apical lesions.

External cervical resorption - Treatment outcomes and determinants: a retrospective cohort study with up to 10 years of follow-up

AIM

To assess long-term external cervical resorption (ECR) treatment outcomes in relation to both local and treatment-related determinants.

METHODOLOGY

Information was available for 76 patients (98 teeth) who were diagnosed with ECR during the period from 2008 to 2018 at the University of British Columbia graduate endodontics clinic. The ECR patients were followed-up, and a clinical and radiographic examination was conducted. Chi-Square test compared failure rates among different subgroups. The survival analysis was used to evaluate the overall ECR survival/failure rates in relation to several local and treatment-related determinants.

RESULTS

Overall, 67 patients (89 teeth) were followed-up. The mean follow-up time was 3.9 years, and the minimum was 1 year. Twenty-four teeth failed (19 extracted, 5 not functional), and the overall probability of failure was 50.0% 8 years after the diagnosis. Significant (p < 0.05) local ECR determinants were tooth location and the Heithersay classification, and treatment-related determinants were root canal treatment (RCT) and the ECR repair combined with RCT. Treatment outcomes for Heithersay class 1 and 2 cases were better than for class 3 and 4 cases.

CONCLUSIONS

Higher failure rates were associated with posterior tooth location and higher Heithersay class, while RCT and ECR repair combined with RCT were associated with lower failure rates.

A Review of External Cervical Resorption

External cervical resorption (ECR) is a relatively uncommon yet aggressive form of dental hard tissue destruction. It is initiated at the cervical aspect of the root surface and extends apicocoronally and circumferentially inside the dentin. Despite the large number of case reports and clinical studies that have investigated ECR, its etiology remains unclear. Recent advancements in clinical assessment measures, such as the use of cone-beam computed tomographic imaging, have provided additional insights into the nature of this lesion. This has facilitated the continued development and improvement of treatment methods for this condition. In this article, we provide an overview of the latest research pertaining to the etiology, histopathology, predisposing factors, diagnosis, classification, and treatment of ECR. Furthermore, we provide a summary of the different classification schemes for ECR and highlight the relevant therapeutic principles.