The Assessment and Management of External Cervical Resorption with Periapical Radiographs and Cone-beam Computed Tomography: A Clinical Study

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.

Influence of tube current and metal artifact reduction on the diagnosis of external cervical resorption in teeth adjacent to a dental implant in CBCT: an ex-vivo study

OBJECTIVES

This ex-vivo study aimed to assess the influence of tube current (mA) and metal artifact reduction (MAR) on the diagnosis of early external cervical resorption (EECR) in cone-beam computed tomography (CBCT) in the presence of an adjacent dental implant.

MATERIALS AND METHODS

Twenty-three single-rooted teeth were sectioned longitudinally and EECR was induced using a spherical drill and 5% nitric acid in 10 teeth. Each tooth was positioned in the socket of the lower right canine of a dry human mandible and CBCT scans were acquired using 90 kVp, voxel of 0.085 mm, field of view of 5 x 5 cm, and varying tube current (4, 8 or 12 mA), MAR (enabled or disabled) and implant conditions (with a zirconia implant in the socket of the lower right first premolar or without). Five oral radiologists evaluated the presence of EECR in a 5-point scale and the diagnostic values (area under the receiver operating characteristic curve - AUC, sensitivity, and specificity) were compared using multi-way Analysis of Variance (α = 0.05). Kappa test assessed intra-/inter-evaluator agreement.

RESULTS

The tube current only influenced the AUC values in the presence of the implant and when MAR disabled; in this case, 8 mA showed lower values (p<0.007). MAR did not influence the diagnostic values (p>0.05). In general, the presence of an implant reduced the AUC values (p<0.0001); sensitivity values with 8 mA and MAR disabled, and specificity values with 4 mA and MAR enabled and 8 mA regardless MAR were also decreased (p<0.0001).

CONCLUSIONS

Variations in tube current and MAR were unable to improve EECR detection, which was impaired by the presence of an adjacent implant.

CLINICAL RELEVANCE

Increasing tube current or activating MAR tool does not improve EECR diagnosis, which is hampered by the artifacts generated by dental implants.

The various forms of tooth resorption

Tooth resorption refers to the loss of the organic and inorganic components of tooth structure by clastic cells. The complex and multifaceted nature of its aetiology, along with the several classification schemes published in the area, are likely to create confusion amongst researchers and clinicians, and may lead to compromised treatment decisions. Therefore, this paper will categorise and address tooth resorption based on aetiology in order to help clinicians diagnose and filter treatment options based on the pathophysiology of the resorption at hand. With recent advancements in the literature, the purpose of this paper is to provide clinicians with a current, clinically relevant summary of the various forms of tooth resorption, with a focus on aetiologically driven treatment strategies and suggestions that facilitate their recognition, diagnosis and management.

An Evaluation of the Fracture Resistance of Teeth with Simulated External Cervical Resorption Cavities Categorized Using Three-Dimensional Classification

(1) Background: External cervical resorption causes dental hard tissue destruction that may reduce the fracture resistance of affected teeth. By using a compressive strength test, this study aimed to evaluate the fracture resistance of teeth with simulated external cervical resorption cavities that have different three-dimensional classifications. (2) Methods: In total, 170 teeth with simulated external cervical resorptions were divided into 16 experimental groups (n = 10) and 1 control group (n = 10) based on the three-dimensional classification: 1Ap, 1Bp, 1Cp, 1Dp, 2Ap, 2Bp, 2Cp, 2Dp, 3Ap, 3Bp, 3Cp, 3Dp, 4Ap, 4Bp, 4Cp, 4Dp and a control group. Defects were restored with mineral trioxide aggregate. The fracture resistances of the samples were statistically analyzed using two-way repeated ANOVA and the Bonferroni correction for multiple comparisons at a significance level of p < 0.05. (3) Results: The lowest resistance to fracture was observed in samples with vertical height level "4" and circumferential spread of "D" (p < 0.001). In the groups with circumferential spreads "B", "C" and "D", there were significant differences between the samples with vertical height levels "1", "2", "3" and "4" regarding fracture resistance (p < 0.001). (4) Conclusions: The circumferential spread and vertical height of the external cervical resorption influenced the fracture resistance of the affected teeth.

Introducing a new auto edge detection technique capable of revealing cervical root resorption in CBCT scans with pronounced metallic artifacts

Cervical resorption is a serious threat to the longevity of the teeth. In this study, the Canny edge-detection algorithm was applied on CBCT images to compare the accuracy of original and Canny views for diagnosing cervical resorption in endodontically treated teeth. Intracanal metallic posts were inserted in 60 extracted teeth being randomly divided into three groups: control, 0.5 mm, and 1 mm cervical resorption. CBCT scans of the teeth were presented to three observers in both original and Canny formats with the accuracy being determined by receiver operating characteristic (ROC) analysis. The DeLong test was used for paired comparisons with the significance level set at 0.05. The highest accuracy belonged to Canny images in 1 mm resorption, followed by Canny images in 0.5 mm resorption, original images in 1 mm resorption, and original images in 0.5 mm resorption, respectively. The Canny images were significantly more accurate in the diagnosis of 0.5 mm (p < 0.001) and 1 mm (p = 0.009) resorption. Application of the Canny edge-detection algorithm could be suggested as a new technique for facilitating the diagnosis of cervical resorption in teeth that are negatively affected by metallic artifacts.

An animal study on the effectiveness of platelet-rich plasma as a direct pulp capping agent

Direct pulp capping (DPC) is a conservative approach for preserving tooth vitality without requiring more invasive procedures by enhancing pulp healing and mineralized tissue barrier formation. We investigated the effectiveness of Platelet Rich Plasma (PRP) vs. Mineral Trioxide Aggregate (MTA) as a DPC agent. Forty-two teeth from three mongrel dogs were divided into two equal groups. After three months, the animals were sacrificed to evaluate teeth radiographically using cone-beam computerized tomography, histopathologically, and real-time PCR for dentin sialophosphoprotein (DSPP), matrix extracellular phosphoglycoprotein (MEPE), and nestin (NES) mRNA expression. Radiographically, hard tissue formation was evident in both groups without significant differences (p = 0.440). Histopathologic findings confirmed the dentin bridge formation in both groups; however, such mineralized tissues were homogenous without cellular inclusions in the PRP group, while was osteodentin type in the MTA group. There was no significant difference in dentin bridge thickness between the PRP-capped and MTA-capped teeth (p = 0.732). The PRP group had significantly higher DSPP, MEPE, and NES mRNA gene expression than the MTA group (p < 0.05). In conclusion, PRP enables mineralized tissue formation following DPC similar to MTA, and could generate better cellular dentinogenic responses and restore dentin with homogenous architecture than MTA, making PRP a promising alternative DPC agent.

Prevalence and Characterization of External Cervical Resorption Using Cone Beam Computed Tomography

INTRODUCTION

The aim of this study was to assess the prevalence of external cervical resorption (ECR) and characterize the cases of ECR using cone beam computed tomography (CBCT).

METHODS

High-resolution CBCT scans of 6216 patients (2280 males and 3936 females), consecutively acquired during the period July 2021 to March 2022, were analyzed. Identified cases of ECR were characterized by 3 evaluators regarding lesion height, circumferential spread, portal of entry proximity to root canal, stage, location, and width.

RESULTS

In a total of 38 patients and 40 teeth, ECR cases demonstrated an incidence of 0.61%. The median age of the patients was 39 years. Prevalence of ERC was 0.78% among males and 0.50% among females. The most affected teeth were the maxillary incisors and canines. The most frequent characteristics of the lesion were: extension up to the cervical third (47.5%), more than 270° circumferential spread (42.55%), probable pulpal involvement (57.5%), progressive stage (65%), supracrestal (52.1%) and mesial (34.7%) localization of >1 mm in size (52.1%) portals of entry. Cases with greater longitudinal involvement also showed greater circumferential progression (P = .008). There was no association between portal of entry location and bone crest or ECR reparative phase (P = .42). Inter-rater agreement ranged from good to very good. No association between portal of entry and ECR progression was observed.

CONCLUSIONS

ECR showed low prevalence in the Brazilian population, affecting mostly anterior maxillary teeth of patients within a wide age range. CBCT allowed characterization of ECR lesions with good interobserver agreement.

Global cone-beam computed tomography adoption, usage and scan interpretation preferences of dentists and endodontists

AIM

This study investigated the adoption of cone-beam computed tomography (CBCT) by dentists and endodontists around the world, including their preferences in endodontic CBCT usage.

METHODOLOGY

An online questionnaire surveyed dental association members in Australia and New Zealand, and endodontic association members in Australia, Britain, Canada, Italy, New Zealand and the USA, about their CBCT training history, considerations in acquisition/interpretation, access to and usage of CBCT, preferred scan interpreter, and preferred endodontic scan settings. Data were analysed with Chi-squared, independent sample t-tests, Cochran's Q and McNemar's tests.

RESULTS

Responses from 578 endodontic specialists or postgraduates (Group E) and 185 non-endodontic dentists (Group NE) were included. Continuing professional education (CPE) was the most common source of CBCT training (69.2%). Factors considered in CBCT acquisition/interpretation included beam hardening (75.4%), radiation exposure (61.1%) and patient movement (58.3%). Group E reported higher CBCT usage (90.8%) than Group NE (45.4%, p < .001) and greater workplace access to CBCT (81.1% vs. 25.9%, p < .001). Scans were interpreted by the respondent in most workplace scans (83.3%) and externally taken scans (60.5%); Group E were significantly more likely to interpret themselves than Group NE. Small field of view (83.6%) and high resolution (86.6%) were most preferred as settings for endodontic CBCTs; Group NE were less likely to choose these settings. There were some geographic variations within Group E.

CONCLUSIONS

CBCT training was most commonly acquired via CPE. Endodontic respondents reported very high CBCT usage and access in the workplace. There are educational implications regarding CBCT limitations, appropriate applications and interpretation.

A Cone-beam Computed Tomography Evaluation of External Invasive Resorption of Unerupted Teeth. Report of Three Cases

Tooth resorption can occur either physiologically or pathologically and can be classified as internal or external. The term "external invasive resorption" (EIR) has been used to describe lesions originating from any surface defect exposing dentin. The absence of bacterial contamination, an intact pulp space, and a lesion consisting mainly of fibrovascular tissue characterize EIR. This study presents three cases of invasive resorption in unerupted teeth, emphasizing the importance of cone-beam computed tomography (CBCT). In two cases, the primary defect localized on the enamel surface, while in the third case, the focal point of the defect was not clear. CBCT provided detailed visualization of the resorption lesion's size and its relationship with surrounding structures, enhancing the diagnosis of EIR. Histological analysis of the third case confirmed the initial diagnosis. Invasive resorption can occur due to any surface defect in the case of unerupted teeth. Further research and correlation between radiographic and histological analysis are essential for the detection and classification systems in unerupted teeth.

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.

A Survey on Cone-beam Computed Tomography Usage Among Endodontists in the United States

INTRODUCTION

The aim of the study was to investigate the accessibility and frequency of cone-beam computed tomography (CBCT) usage and to assess the economic and logistical factors involved with its usage among active American Association of Endodontists (AAE) members, utilizing a web-based survey.

METHODS

A survey of 19 questions was sent to 3,071 AAE members addressing participant access to, along with financial and logistical aspects of CBCT imaging. Descriptive analysis was performed and Fisher exact test utilized to test associations between groups (P < .05).

RESULTS

The overall response rate was 14.7% (n = 544). Ninety-five percent of respondents (n = 486) had an in-office CBCT unit, with those graduating after the year 2000 statistically more likely to have one (P < .05). Utilization of CBCT imaging for every case was reported by 40% of providers. Eighty-nine percent reported taking the scan at the consultation visit and 20% included this charge with the consultation fee. For those who charged for the scan separately, 85% charged more than $100. Providers who paid off their unit did so within 1-2 years (41%), 3-4 years (36%), 4-5 years (12%), and 5+ years (11%). Limited field of view was utilized by 95% of respondents. Fifty-eight percent reported interpreting the scans themselves, 38% send only if pathology is expected, and 3% always send their scans to a radiologist.

CONCLUSIONS

In conclusion, accessibility and utilization of CBCT imaging among United States endodontists has increased and acquisition of this equipment has not made a long lasting financial burden on providers.

Reprint of: Prevalence and Characteristics of Root Resorption Identified in Cone-Beam Computed Tomography Scans

INTRODUCTION

Root resorption is a destructive process that compromises tooth structure and can result in tooth loss. Often it remains asymptomatic and is an incidental finding on radiographic examinations. The purpose of this study was to determine prevalence and characteristics of root resorption in patients referred for cone-beam computed tomography (CBCT) imaging for a variety of indications.

METHODS

The study included CBCT scans of 1086 consecutive patients referred for CBCT imaging over an 18-month period. A total of 1148 scans were acquired. Data were abstracted from radiology reports, and prevalence estimates of resorption were computed for the aggregate sample and also across specific indications.

RESULTS

Resorption was identified in 171 patients (15.7%, 95% CI: 13.6%-17.9%) and in 249 teeth with a prevalence range of 2.6%-92.3% across specific indications. An 18.7% of the patients had 2 resorption sites whereas 8.8% had 3 or more resorption sites. The majority of affected teeth were anteriors (43.8%), followed by molars (40.6%) and premolars (14.5%). The most prevalent resorption types were external (29.3%), cervical (22.5%), infection-induced apical resorption (13.7%), internal (9.6%), and impacted tooth induced (8.8%). The majority of teeth with resorption did not have prior endodontic treatment (73.9%) and had radiographically normal periapex (69.5%). Of 249 teeth with resorption, 31% presented as incidental finding. The prevalence of incidental findings of resorption increased with age, P < .05, and was significantly lower for anterior teeth (20.2%) as compared to premolars (41.7%) and molars (36.6%), (P < .05).

CONCLUSION

The high proportion of incidental findings of resorption detected by CBCT suggests that resorption is not recognized/detected by conventional radiography and therefore remains underdiagnosed.

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.

Intentional replantation and management of avulsion related ankylosis and external cervical resorption. A 10-year follow up case report

Replantation is the treatment of choice for avulsed permanent teeth; ankylosis and cervical root resorption are among survival complications. A 9.5-year-old boy presented with an avulsed maxillary permanent central incisor with an open root apex following a school accident. The tooth was kept in milk, after a dry time of 15-20 min. Its replantation was performed 60 min after the accident. At 8 months, apexification with apical plug was attempted upon radiographic evidence of apical periodontitis. Ankylosis sound with infraocclusion and radiographic evidence of external cervical root resorption (ECR) were evident at 3 years and 3 months. At the patient's return one year later with esthetic concerns (2 mm infraocclusion) there was a 5 mm diameter ECR cavity. After intentional atraumatic extraction the resorptive cavity was debrided and restored with Biodentine; subsequently the tooth was reimplanted and splinted at an extruded position. At the 10-year follow up since the first avulsion the tooth remains esthetically pleasing, asymptomatic, non-ankylotic and functional. The present case supports intentional replantation as an option in managing infraoccluded teeth with advanced ECR.

Prevalence and Characteristics of Root Resorption Identified in Cone-Beam Computed Tomography Scans

INTRODUCTION

Root resorption is a destructive process that compromises tooth structure and can result in tooth loss. Often it remains asymptomatic and is an incidental finding on radiographic examinations. The purpose of this study was to determine prevalence and characteristics of root resorption in patients referred for cone-beam computed tomography (CBCT) imaging for a variety of indications.

METHODS

The study included CBCT scans of 1086 consecutive patients referred for CBCT imaging over an 18-month period. A total of 1148 scans were acquired. Data were abstracted from radiology reports, and prevalence estimates of resorption were computed for the aggregate sample and also across specific indications.

RESULTS

Resorption was identified in 171 patients (15.7%, 95% CI: 13.6%-17.9%) and in 249 teeth with a prevalence range of 2.6%-92.3% across specific indications. An 18.7% of the patients had 2 resorption sites whereas 8.8% had 3 or more resorption sites. The majority of affected teeth were anteriors (43.8%), followed by molars (40.6%) and premolars (14.5%). The most prevalent resorption types were external (29.3%), cervical (22.5%), infection-induced apical resorption (13.7%), internal (9.6%), and impacted tooth induced (8.8%). The majority of teeth with resorption did not have prior endodontic treatment (73.9%) and had radiographically normal periapex (69.5%). Of 249 teeth with resorption, 31% presented as incidental finding. The prevalence of incidental findings of resorption increased with age, P < .05, and was significantly lower for anterior teeth (20.2%) as compared to premolars (41.7%) and molars (36.6%), (P < .05).

CONCLUSION

The high proportion of incidental findings of resorption detected by CBCT suggests that resorption is not recognized/detected by conventional radiography and therefore remains underdiagnosed.

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.

Influence of cone beam computed tomography on endodontic treatment planning: A systematic review

OBJECTIVES

The aim of this systematic review was to evaluate how treatment plans changed when cone beam computed tomography (CBCT) imaging was used in endodontic treatment decision-making.

DATA

Studies examining changes in clinicians' treatment plans with and without the use of CBCT were included. Risk of bias assessment was completed using a modification of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool.

SOURCES

A systematic search was performed in PubMed, Embase, Scopus, Cochrane databases from inception to 14 September 2021.

STUDY SELECTION

The initial search identified 3379 titles and abstracts; 20 articles fulfilled inclusion and exclusion criteria for full text review. An additional three articles were identified through citation searching. Sixteen studies met inclusion and exclusion criteria for data extraction and analysis. Fifteen studies reported changes in treatment plan with CBCT imaging. Five studies reported changes in 45 - 66.7% of the cases but did not mention specific treatment options. Of the 11 remaining studies, 10 studies reported changes in 24.3 - 56% of cases and changes in treatment options, while one study reported no significant change in treatment plan after CBCT imaging was introduced. With CBCT imaging, clinicians were more likely to prescribe further intervention that included endodontic treatment and extractions.

CONCLUSION

Although the current evidence was heterogeneous, it was clear that CBCT offered more information than periapical radiography. This influenced endodontic treatment decision-making and in more complex cases, led to further intervention including non-surgical and surgical endodontic treatment and extractions.

CLINICAL SIGNIFICANCE

Additional information from CBCT imaging influenced endodontic treatment decision-making in the following situations: high difficulty cases, diagnosis of symptomatic teeth after failed root canal treatment, evaluation of periapical healing, pre-surgical treatment planning, and management of traumatised immature teeth and external cervical resorption.

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.

Three-Dimensional tooth models for better teaching and treatment outcomes

INTRODUCTION

The aim of this study was to fabricate 3-Dimensional (3D) tooth models to overcome procedural errors that occur during treatment and to improve endodontic management of teeth with complex pulp morphology and dental anomalies.

MATERIALS AND METHODS

Three natural teeth were used to fabricate resinous tooth models (n = 90) and 90 natural teeth were used during root canal treatment. Models were fabricated from 1 mandibular canine (n = 30) and 2 maxillary molars (n = 60). Natural teeth were 30 mandibular canines, 30 mandibular molars and 30 maxillary molars.

RESULTS

Natural teeth and opaque resin models were significantly better than the clear resin models during access preparation (p = .003). In addition, the clear resin models were significantly better than the natural teeth and opaque resin models during shaping, obturation and as an educational tool (p < .001, p < .001 and p < .001 respectively).

CONCLUSIONS

Although it takes more time and effort to produce 3D (3D) tooth models from each natural tooth used in the study, it can give more accurate results during evaluation.

Influence of Cone-beam Computed Tomography in clinical decision-making among different specialists in External Cervical Resorption lesions: a before-after study

INTRODUCTION

Inadequate management of external cervical resorption (ECR) lesions may impact the treatment outcome. This study aimed to ascertain the influence of cone-beam computed tomography (CBCT) in clinical decision-making choices in cases of ECR among dentistry specialists (endodontics, prosthodontics, oral surgery, periodontics orthodontics, and general dentistry). A secondary objective was to evaluate the self-reported level of difficulty in choosing a treatment plan before and after viewing the CBCT images.

METHODS

Sixty examiners from different specialties were chosen to evaluate 12 cases of ECR lesions. Each case included clinical photographs, digital periapical (PA) radiographs, and a small-volume CBCT scan. In the first assessment, the examiners were given all the relevant information of each case, except the CBCT scan. Each examiner was asked to select 1 of the proposed treatment options and assess the difficulty of decision making. Four weeks later, the examiners randomly reviewed the same 12 cases with additional information from the CBCT data.

RESULTS

After the CBCT evaluation, the clinicians changed their treatment plan in 72.2% of the cases (P < .05). The self-reported level of difficulty in choosing a treatment changed in all groups after evaluating the CBCT scans (P< .05). After viewing the CBCT scan, the extraction option increased significantly in all groups (P < .05).

CONCLUSIONS

CBCT scan had a significant impact on clinical decision-making in cases of ECR evaluated by different specialists.

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.

Impact of cone beam CT on diagnosis of external cervical resorption: the severity of resorption assessed in periapical radiographs and cone beam CT. A prospective clinical study

OBJECTIVES

To compare the severity of external cervical resorption (ECR) observed in periapical (PA) images and cone beam CT (CBCT) using the Heithersay classification system and pulp involvement; and to assess inter- and intraobserver reproducibility for three observers.

METHODS

CBCT examination was performed in 245 teeth (in 190 patients, mean age 40 years, range 12-82) with ECR diagnosed in PA images. Three observers scored the severity of ECR using the Heithersay classification system (severity class 1-4) and pulp involvement (yes/no) in both PA images and CBCT. Percentage concordance and κ-statistics described observer variation in PA images and CBCT for both inter- and intraobserver reproducibility.

RESULTS

For all three observers, the ECR score was the same in the two modalities in more than half of cases (average 59%; obs1: 54%, obs2: 63%, obs3: 61%). However, in 38% (obs1: 44%, obs2: 33%, obs3: 36%) of the cases, the observers scored more severe ECR in CBCT than in PA images (p < 0.001). The ECR score changed to a less severe score in CBCT only in 3% (obs1: 1%, obs2: 4%, obs3: 4%). For pulp involvement, 14% (obs1: 7%, obs2: 20%, obs3: 15%) of the cases changed from "no" in PA images to "yes" in CBCT. In general, κ values were higher for CBCT than for PA images for both the Heithersay classification score and pulp involvement.

CONCLUSIONS

ECR was generally scored as more severe in CBCT than PA images using the Heithersay classification and also more cases had pulp involvement in CBCT.

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.

CBCT-based assessment of root canal treatment using micro-CT reference images

Purpose

This study compared the root canal anatomy between cone-beam computed tomography (CBCT) and micro-computed tomography (micro-CT) images before and after biomechanical preparation and root canal filling.

Materials and Methods

Isthmus-containing mesial roots of mandibular molars (n=14) were scanned by micro-CT and 3 CBCT devices: 3D Accuitomo 170 (ACC), NewTom 5G (N5G) and NewTom VGi evo (NEVO). Two calibrated observers evaluated the images for 2-dimensional quantitative parameters, the presence of debris or root perforation, and filling quality in the root canal and isthmus. The kappa coefficient, analysis of variance, and the Tukey test were used for statistical analyses (α=5%).

Results

Substantial intra-observer agreement (κ=0.63) was found between micro-CT and ACC, N5G, and NEVO. Debris detection was difficult using ACC (42.9%), N5G (40.0%), and NEVO (40%), with no agreement between micro-CT and ACC, N5G, and NEVO (0.05<κ<0.12). After biomechanical preparation, 2.4%-4.8% of CBCT images showed root perforation that was absent on micro-CT. The 2D parameters showed satisfactory reproducibility between micro-CT and ACC, N5G, and NEVO (intraclass correlation coefficient: 0.60-0.73). Partially filled isthmuses were observed in 2.9% of the ACC images, 8.8% of the N5G and NEVO images, and 26.5% of the micro-CT images, with no agreement between micro-CT and ACC, and poor agreement between micro-CT and N5G and NEVO. Excellent agreement was found for area, perimeter, and the major and minor diameters, while the roundness measures were satisfactory.

Conclusion

CBCT images aided in isthmus detection and classification, but did not allow their classification after biomechanical preparation and root canal filling.

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).

Comparison of imaging modalities in the diagnosis of external cervical resorption (ECR): an in-vitro study

External cervical resorption is a pathological condition affecting the cervical margins of teeth. Due to the increased prevalence and the area it affects, it can be easily misdiagnosed. The ability of clinicians to diagnose ECR and subcategorise the lesions using periapical radiographs and cone beam-CT scans has not been investigated in-depth. This study aims to assess if diagnostic ability to detect ECR lesions with the two modalities was different and if there was a change in the diagnosis when CBCT was used. A human skull, including the mandible was used for this study. The teeth were randomly allocated to the different subcategories, then pre and post-preparation radiographs with CBCT were taken. Statistical analysis was done using IBM SPSS version 16.0 (SPSS Inc., Chicago, IL, USA). The study sample was composed of 60 participants, the overall sensitivity of intraoral radiographs was significantly lower than CBCT. When the participants were told the radiograph and the CBCT were of the same tooth 60% said they would change their diagnosis. The use of intraoral radiographs alone might not be enough to identify and correctly diagnose ECR lesions. CBCT can give a better idea about the nature and the extent of the lesion.

Comparative analysis of the accuracy of periapical radiography and cone-beam computed tomography for diagnosing complex endodontic pathoses using a gold standard reference - A prospective clinical study

AIM

To compare the diagnostic accuracy of periapical radiography (PR) and cone-beam computed tomography (CBCT) for detecting pathoses of endodontic origin using the gold standard of direct surgical visualization.

METHODOLOGY

Seventy-four patients (112 teeth) underwent radiographic examination by periapical radiography and CBCT. The presence of periapical lesions, root perforations and their locations, root fractures, different types of external root resorptive defects, apicomarginal bone defects, through and through bone defects, buccal bone status and proximity of root apices and lesions to vital anatomical structures were assessed. These same parameters were assessed intraoperatively by direct surgical visualization which served as the gold standard reference for the radiographic assessments. Sensitivity, specificity, positive predictive values, negative predictive values were determined for comparison of diagnostic accuracy between two modalities.

RESULTS

There were no significant differences between the two imaging modalities for root resorptive defects and root fractures. However, CBCT accurately detected periapical lesions, root perforations, apicomarginal bone defects and through and through bone defects. The overall accuracy of CBCT varied from 91% to 96% in detecting dehiscence and fenestration of buccal cortical plates.

CONCLUSION

Overall, CBCT had a higher diagnostic accuracy in complex endodontic pathoses compared to PR. Nevertheless, CBCT failed to diagnose apicomarginal bone defects in 33% teeth. In evaluating the status of buccal cortical plate from CBCT images, observers could detect absence of bone better than its presence. Thus, limited FOV CBCT should be considered for selective cases where periapical radiography has diagnostic ambiguity.

CBCT influences endodontic therapeutic decision-making in immature traumatized teeth with suspected pulp necrosis: a before-after study

OBJECTIVE

To evaluate the impact of cone-beam computed tomography (CBCT) in endodontic therapeutic decision-making of immature traumatized teeth with suspected pulp necrosis.

METHODS

Over two years, consecutive patients with a dental trauma in their front teeth (apex >0.5 mm) and with suspected pulp necrosis based on clinical and radiographic findings were referred to a specialist clinic in Sweden. Fifteen patients aged 6-13 (18 teeth) were included and clinically examined by an endodontist. Intraoral radiographs and CBCT examinations were obtained. Five practitioners, three endodontists and two residents in endodontics, used these examinations to determine the most appropriate treatment for the 18 cases (all central incisors) on two occasions scheduled 19 weeks apart. On the first occasion, the practitioners had access to clinical information and the intraoral radiographs ('before' CBCT); on the second occasion, the practitioners had also access to a radiologist report and the CBCT images ('after' CBCT). Their treatment plans - no treatment, watchful waiting, endodontic orthograde treatment, or extraction - were made anonymously and independently. Results were analysed using descriptive statistics and Wilcoxon signed-rank test.

RESULTS

'After' CBCT, practitioners changed treatment plans in 30% of the 90 assessments, 74% of which were more aggressive (p = 0.028). In 49% of the assessments, practitioners who chose the watchful and waiting treatment plan 'before' CBCT changed to a more aggressive therapy such as endodontic orthograde treatment and extraction 'after' CBCT (p = 0.005).

CONCLUSION

This study provides evidence that CBCT influences endodontic therapeutic decision-making regarding immature traumatised teeth with suspected pulp necrosis, chiefly when expectant management (i.e., watchful and waiting) was selected before access to CBCT.

Diagnosis and Management of Traumatic Dental Injuries Using Intraoral Radiography and Cone-beam Computed Tomography: An In Vivo Investigation

INTRODUCTION

The aim of this study was to compare periapical radiographs (PRs) and upper standard occlusal (USO) radiographs with cone-beam computed tomographic (CBCT) imaging on clinicians' confidence in the diagnosis and management of traumatic dental injuries (TDIs).

METHODS

This study included 35 maxillary anterior teeth from 25 patients with at least 1 PR (parallax view) and a CBCT scan. Fourteen patients also had a USO radiograph. Ten examiners selected a diagnosis and treatment plan, which were compared with a reference standard. Sensitivity, specificity, positive and negative predictor values, and receiver operating characteristic analysis were used to determine the diagnostic accuracy.

RESULTS

CBCT imaging exhibited significantly higher sensitivity than both conventional radiographic techniques combined (PRs and PRs + USO radiographs) for all diagnoses (TDI: 99% vs 84%, lateral luxation: 80% vs 34%, extrusions: 92% vs 42%, and cortical plate fracture: 58% vs 1%) other than horizontal root fractures in which the results were close to statistical significance (88% vs 69%). CBCT imaging was significantly more accurate for all diagnoses (TDI: 91% vs 70%, lateral luxations: 83% vs 61%, extrusive luxations: 92% vs 68%, alveolar cortical plate fractures: 78% vs 48%, and horizontal root fractures: 93% vs 82%). Examiners had the most confidence with CBCT imaging and the least confidence in diagnosing using PRs + USO radiographs than with PRs alone. Agreement with management plans was significantly better using CBCT imaging compared with PRs and PRs + USO radiographs.

CONCLUSIONS

CBCT imaging improved the clinical diagnosis of TDIs. The addition of USO radiographs to PRs did not improve the diagnosis of TDIs in this investigation. CBCT imaging improved confidence in the diagnosis of TDI cases and treatment planning compared with conventional radiography.

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.

The association of external cervical resorption with modern internal bleaching protocols: what is the current evidence?

Internal bleaching is an effective and minimally invasive way of bleaching non-vital teeth. A commonly cited risk associated with it is external cervical resorption (ECR), which is a potentially significant complication that could result in loss of the tooth. This is an important point of discussion with a patient during the consent process. Legally, patients are required to be made aware of material risks to which they would be likely to attach significance, such as the loss of a tooth. The risk of ECR is therefore a key component in the patient's decision-making process as they weigh it against the perceived benefits. Over the last ten years, both clinical and legal reasons have resulted in a number of changes in the materials and protocols used for internal bleaching. This leads to the question of what the current quality of evidence is regarding the association of ECR following internal bleaching with modern protocols. Other restorative options for discoloured teeth, such as veneers or crowns, involve the irreversible removal of tooth tissue and these may be chosen by patients over internal bleaching based on out-of-date evidence.

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.

The impact of different voxels and exposure parameters of CBCT for the assessment of external root resorptions: A phantom study

This study aimed to compare the effectiveness of the different voxel sizes and imaging parameters of cone beam computed tomography (CBCT) on the determination of external root resorption (ERR). ERRs were created in coronal, middle and apical regions. Depths (0.62-0.73 mm) and diameters (0.68-0.81 mm) of ERRs were measured using a digital calliper. Images were obtained in 0.125, 0.2, 0.25, 0.3 and 0.4 mm³ voxel sizes and at different currents. Data were analysed using Friedman and Wilcoxon signed-rank tests at a level of P < 0.05. There was a difference between the parameters in determining the size of the ERR in coronal and middle regions (P < 0.05), but there was no difference in the apical region (P > 0.05). The change in current and exposure time did not make a difference in determining the dimensions of the ERRs (P > 0.05). Some voxel dimensions were more reliable in determining the depth and diameter of ERR in the coronal and middle region.

An unusual case of invasive cervical resorption after piezosurgery-assisted en masse retraction

A 16-year-old patient sought orthodontic correction for profile improvement and labially inclined maxillary incisors. She had Class II malocclusion, protrusive maxillary and mandibular incisors, and increased overjet and overbite with an American Board of Orthodontics discrepancy index value of 25. She was treated with maxillary premolar extractions and miniscrew-supported en masse retraction assisted with piezoincisions. Extraction spaces (7.5 mm per side) were closed with maximum anchorage in 10 months. Total treatment time was 23 months. Twenty-seven months after debonding, a pink spot was noted at the buccocervial region of the left central incisor. Radiographic evaluation on cone-beam computed tomographic scans revealed a severe case of invasive cervical resorption on both central incisors, around which the piezosurgical cuts had been made. Treatment proceeded with a nonintervention approach and the affected teeth were reinforced with a lingual retainer.

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.

CBCT analyses of advanced cervical resorption aid in selection of treatment modalities: a retrospective analysis

OBJECTIVES

The selection of treatment for advanced (classes 3 and 4) invasive cervical resorption (ICR) based on a two-dimensional periapical radiograph is challenging. The purpose of the present study is to describe different treatment approaches for advanced invasive cervical resorption based on cone-beam computed tomography evaluation.

MATERIALS AND METHODS

All cases of advanced ICR based on CBCT evaluation in our endodontic department between 2011 and 2016 were included in the study. The dimension, circumferential, and coronal-cervical locations of the entry point of the resorption tissue into the tooth were evaluated. The selected treatment approach for each case was documented, and all the data were summarized and analyzed.

RESULTS

Twenty-three cases of advanced ICR were included in the study. Approximately, 74% were diagnosed in stage 4, and 26% were diagnosed in stage 3. The narrow entry point was identified in 43% (10 cases), while in 57% (13) of cases, the entry point was wide. Circumferentially, 70% (16) were located on the proximal side. Coronal-cervically, 43% (10) were located more than 1.5 mm above the crestal bone. All narrow entry point cases were treated using a minimally invasive technique, while different treatment approaches were chosen for cases with a wide entry point.

CONCLUSIONS

The present study proposes different treatment approaches for advanced ICR based on CBCT. The CBCT evaluation of the entry point may facilitate choosing the appropriate treatment approach for advanced ICR cases.

CLINICAL RELEVANCE

The description of different treatment approaches for advanced invasive cervical resorption based on cone-beam computed tomography evaluation enables the clinician to choose the optimal treatment approach for each advanced ICR case.

The Diagnostic Yield of Dental Radiography and Cone-Beam Computed Tomography for the Identification of Dentoalveolar Lesions in Cats

The objective of this study was to evaluate the diagnostic yield of dental radiography (DR) and 3 cone-beam computed tomography (CBCT) software modules for the identification of 32 pre-defined dentoalveolar lesions in cats. For 5 feline cadaver heads and 22 client-owned cats admitted for evaluation and treatment of dental disease, 32 predefined dentoalveolar lesions were evaluated separately and scored by use of dental radiography and 3 CBCT software modules [multiplanar reconstructions (MPR), tridimensional (3-D) rendering, and reconstructed panoramic views]. A qualitative scoring system was used. Dentoalveolar lesions were grouped into 14 categories for statistical analysis. Point of reference for presence or absence of a dentoalveolar lesion was determined as the method that could be used to clearly identify the disorder as being present. Accuracy, sensitivity, specificity, and positive and negative predictive values were calculated with the McNemar χ2 test of marginal homogeneity of paired data. When all 3 CBCT software modules were used in combination, the diagnostic yield of CBCT was significantly higher than that of dental radiography for 4 of 14 categories (missing teeth, horizontal bone loss, loss of tooth integrity, feline resorptive lesions), and higher, although not significantly so, for 9 categories (supernumerary teeth, supernumerary roots, abnormally shaped roots, vertical bone loss, buccal bone expansion, periapical disease, inflammatory root resorption, and external replacement root resorption). In conclusion, we found that CBCT provided more clinically relevant detailed information as compared to dental radiography. Therefore, CBCT should be considered better suited for use in diagnosing dentoalveolar lesions in cats.

Invasive Cervical Resorption: Clinical Management in the Anterior Zone

According to the high number of articles published on invasive cervical resorption (ICR), this pathology, as commonly believed, is a more frequent form of cervical resorption. ICR is often misdiagnosed as internal resorption or caries, which leads to inappropriate treatment and even unnecessary tooth loss. Despite a correct diagnosis, the treatment of this type of hyperplastic invasive external resorption poses a challenge for the clinician. The Heithersay classification and the use of cone-beam computed tomographic imaging have increased our knowledge of the pathology and helped improve its prognosis. Nevertheless, there is no standard protocol for the treatment of this type of lesion. This article proposes a treatment protocol for ICR based on the pattern and location of resorption. Three treatment approaches (internal access, external access, and intentional replantation) are presented through 3 clinical cases.

External invasive resorption: Possible coexisting factors and demographic and clinical characteristics

The purpose of this retrospective study was to identify the coexisting factors for EIR and to characterise EIR clinically and demographically. All cases of EIR that were referred to the endodontic department between 2011 to 2016 and diagnosed by an endodontist were evaluated. Demographic and clinical characteristics were collected and evaluated. Thirty-eight cases of EIR diagnosed between 2011 and 2016 were included in the study. Seventy-one percent of EIR cases were misdiagnosed by general practitioners. The most affected teeth were the maxillary central incisors (29% of cases) and mandibular molars (26%). Sixty-eight percent of EIR cases were diagnosed in teeth with clinically normal pulp. Pulp necrosis was observed mainly in the advanced stages (class 3 and class 4) of EIR (75%) and in teeth with a history of trauma (63%). Histories of previous trauma and orthodontic treatment were reported in 29% and 23% of cases, respectively.

External cervical resorption: part 2 - management

Effective management of external cervical resorption (ECR) depends on accurate assessment of the true nature and accessibility of ECR; this has been discussed in part 1 of this 2 part article. This aim of this article was firstly, to review the literature in relation to the management of ECR and secondly, based on the available evidence, describe different strategies for the management of ECR. In cases where ECR is supracrestal, superficial and with limited circumferential spread, a surgical repair without root canal treatment is the preferred approach. With more extensive ECR lesions, vital pulp therapy or root canal treatment may also be indicated. Internal repair is indicated where there is limited resorptive damage to the external aspect of the tooth and/or where an external (surgical) approach is not possible due to the inaccessible nature of subcrestal ECR. In these cases, root canal treatment will also need to be carried out. Intentional reimplantation is indicated in cases where a surgical or internal approach is not practical. An atraumatic extraction technique and short extraoral period followed by 2-week splinting are important prognostic factors. Periodic reviews may be indicated in cases where active management is not pragmatic. Finally, extraction of the affected tooth may be the only option in untreatable cases where there are aesthetic, functional and/or symptomatic issues.

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.

Evaluation of the diagnostic yield of dental radiography and cone-beam computed tomography for the identification of dental disorders in small to medium-sized brachycephalic dogs

OBJECTIVE To evaluate the diagnostic yield of dental radiography (Rad method) and cone-beam CT (CBCT) methods for the identification of 31 predefined dental disorders in brachycephalic dogs. ANIMALS 19 client-owned brachycephalic dogs admitted for evaluation and treatment of dental disease. PROCEDURES 31 predefined dental disorders were evaluated separately and scored by use of dental radiography and 3 CBCT software modules (serial CBCT slices and custom cross sections, tridimensional rendering, and reconstructed panoramic views). A qualitative scoring system was used. Dental disorders were grouped into 10 categories for statistical analysis. Point of reference for presence or absence of a dental disorder was determined as the method that could be used to clearly identify the disorder as being present. Accuracy, sensitivity, specificity, and positive and negative predictive values were calculated with the McNemar χ² test of marginal homogeneity of paired data. RESULTS When all 3 CBCT methods were used in combination, the diagnostic yield of CBCT was significantly higher than that of dental radiography for 4 of 10 categories (abnormal eruption, abnormally shaped roots, periodontitis, and tooth resorption) and higher, although not significantly so, for all categories, except for 1 (loss of tooth integrity). CONCLUSIONS AND CLINICAL RELEVANCE CBCT provided more detailed information than did dental radiography. Therefore, CBCT would be better suited for use in diagnosing dental disorders in brachycephalic dogs.

Impact of Cone-beam Computed Tomography on Treatment Planning for External Cervical Resorption and a Novel Axial Slice-based Classification System

INTRODUCTION

The aim of this study was to compare treatment plans for external cervical resorption (ECR) developed from periapical (PA) radiographs and cone-beam computed tomographic (CBCT) imaging. The secondary aim of this study was to test a new classification system for ECR based on CBCT axial slice analysis.

METHODS

ECR was identified in 56 teeth (47 patients) from a database of 928 CBCT images. Strict exclusion criteria resulted in a sample of 30 ECR teeth (25 patients) and 10 ECR-free control teeth. Six examiners evaluated CBCT and matched PA images in separate sessions. Examiners classified ECR according to the Heithersay classification system and the novel Rohde classification system and provided a treatment plan.

RESULTS

All 30 ECR cases were identified by CBCT imaging and 29 by PA radiography. Interrater agreement was uniformly higher with CBCT imaging, and treatment plans developed from CBCT scans differed from those developed with PA radiographs in 56.7% of the cases. Examiners recommended ECR repair in the majority of cases (59.8% of CBCT images and 56.7% of PA radiographs). The Heithersay classification was dependent on the method of imaging with a greater prevalence of class 4 reported with CBCT imaging (P = .0016). The Rohde classification system significantly predicted the recommended treatment plan (P = .002 for Rohde class 2 and P = .043 for Rohde class 3). All Heithersay classifications failed to statistically predict treatment plans.

CONCLUSIONS

Treatment plans changed between PA and CBCT imaging in the majority of cases evaluated. If CBCT imaging is available, the Rohde classification system may help guide treatment planning for cases of ECR.