Aim
To understand the patterns of external cervical resorption (ECR) in endodontically treated teeth. To compare characteristics and mechanisms of ECR in root filled teeth with those established in ...teeth with vital pulps.
Methodology
Seven cases of endodontically treated permanent teeth displaying ECR were investigated. ECR diagnosis was based on clinical findings and radiographic examination with cone‐beam computed tomography. The extracted teeth were further analysed by a nano‐focus computed tomographic (nano‐CT) system, hard‐tissue histology and scanning electron microscopy (SEM). To make a comparison with teeth with vital pulps, representative cases with ECR were also included.
Results
All endodontically treated teeth had a similar ECR pattern. This pattern reflected many similarities to that seen in teeth with vital pulps; that is, three stages were observed namely initiation, resorption and repair. In particular, during the initiation stage (1st stage), the resorption started below the gingival epithelial attachment, at the level of cementum. In the resorption stage (2nd stage), ECR spreads towards the treated pulp space and in a coronal–apical direction, creating multiple resorption channels. The pulp and the pericanalar resorption resistant sheet (PRRS) had been removed during root canal treatment and thus offered no retarding or defence mechanism towards ECR. In the reparative stage (3rd stage), reparative hard‐tissue formation occurred at a localized scale.
Conclusions
Similar ECR patterns were observed in all examined teeth. These patterns consisted of an initiation, a resorption and a reparative stage. Some differences were noticed between endodontically treated and teeth with vital pulps, mainly in the resorption and reparative stages. The resorption stage in root filled teeth was more intense than the repair stage, as many clastic cells and abundant granulation tissue were observed in all samples. This is possibly due to the absence of the pulp and protective PRRS layer and/or to the altered chemical composition of the root dentine after root canal treatment. Furthermore, at the repair stage, formation of reparative bonelike tissue took place to a lesser extent in root filled teeth.
Abstract Introduction The aim of this study was to investigate the 3-dimensional (3D) structure and the cellular and tissue characteristics of external cervical resorption (ECR) in vital teeth and to ...understand the phenomenon of ECR by combining histomorphological and radiographic findings. Methods Twenty-seven cases of vital permanent teeth displaying ECR were investigated. ECR diagnosis was based on clinical and radiographic examination with cone-beam computed tomographic imaging. The extracted teeth were further analyzed by using nanofocus computed tomographic imaging, hard tissue histology, and scanning electron microscopy. Results All examined teeth showed some common characteristics. Based on the clinical and experimental findings, a 3-stage mechanism of ECR was proposed. At the first stage (ie, the initiation stage), ECR was initiated at the cementum below the gingival epithelial attachment. At the second stage (ie, the resorption stage), the resorption invaded the tooth structure 3-dimensionally toward the pulp space. However, it did not penetrate the pulp space because of the presence of a pericanalar resorption-resistant sheet. This layer was observed to consist of predentin, dentin, and occasionally reparative mineralized (bonelike) tissue, having a fluctuating thickness averaging 210 μm. At the last advanced stage (ie, the repair stage), repair took place by an ingrowth and apposition of bonelike tissue into the resorption cavity. During the reparative stage, repair and remodeling phenomena evolve simultaneously, whereas both resorption and reparative stages progress in parallel at different areas of the tooth. Conclusions ECR is a dynamic and complex condition that involves periodontal and endodontic tissues. Using clinical, histologic, radiographic, and scanning microscopic analysis, a better understanding of the evolution of ECR is possible. Based on the experimental findings, a 3-stage mechanism for the initiation and growth of ECR is proposed.
To analyze the buccal bone thickness, bone depth, and cortical bone depth of the mandibular buccal shelf (MBS) to determine the most suitable sites of the MBS for mini-screw insertion.
The sample ...included cone-beam computed tomographic (CBCT) records of 30 adult subjects (mean age 30.9 ± 7.0 years) evaluated retrospectively. All CBCT examinations were performed with the i-CAT CBCT scanner. Each exam was converted into DICOM format and processed with OsiriX Medical Imaging software. Proper view sections of the MBS were obtained for quantitative and qualitative evaluation of bone characteristics.
Mesial and distal second molar root scan sections showed enough buccal bone for mini-screw insertion. The evaluation of bone depth was performed at 4 and 6 mm buccally to the cementoenamel junction. The mesial root of the mandibular second molar at 4 and 6 mm showed average bone depths of 18.51 mm and 14.14 mm, respectively. The distal root of the mandibular second molar showed average bone depths of 19.91 mm and 16.5 mm, respectively. All sites showed cortical bone depth thickness greater than 2 mm.
Specific sites of the MBS offer enough bone quantity and adequate bone quality for mini-screw insertion. The insertion site with the optimal anatomic characteristics is the buccal bone corresponding to the distal root of second molar, with screw insertion 4 mm buccal to the cementoenamel junction. Considering the cortical bone thickness of optimal insertion sites, pre-drilling is always recommended in order to avoid high insertion torque.
Under the patterning cascade model (PCM) of cusp development inspired by developmental genetic studies, it is predicted that the location and the size of later-forming cusps are more variable than ...those of earlier-forming ones. Here we assessed whether differences in the variability among cusps in total and each particular crown component (enamel-dentin junction EDJ, outer enamel surface OES, and cement-enamel junction CEJ) could be explained by the PCM, using human maxillary permanent first molars (UM1) and second deciduous molars (um2). Specimens were µCT-scanned, and 3D models of EDJ and OES were reconstructed. Based on these models, landmark-based 3D geometric morphometric analyses were conducted. Size variability in both tooth types was generally consistent with the above prediction, and the differences in size variation among cusps were smaller for the crown components completed in later stages of odontogenesis. With a few exceptions, however, the prediction was unsupported regarding shape variability, and UM1 and um2 showed different patterns. Our findings suggested that the pattern of size variability would be caused by temporal factors such as the order of cusp initiation and the duration from the beginning of mineralization to the completion of crown formation, whereas shape variability may be affected by both topographic and temporal factors.
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.
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).
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%).
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.
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.
Invasive cervical resorption (ICR) is a type of external resorption that can involve the coronal, middle, and apical parts of the root in its advanced stages. The diagnosis and treatment of ICR ...depend on the extent of the resorption into the dentin. The treatment of advanced ICR is challenging, and these teeth have poor prognoses. This article describes 4 cases of class 4 ICR diagnosed by using cone-beam computed tomography and treated with a minimally invasive internal approach with sodium hypochlorite irrigation and calcium hydroxide dressing. All cases were followed for at least 3 years.
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).
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.
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.
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.
The aim of this study is prognostic assessment of surface smoothness and the presence of internal bubbles after treatment of non-cancerous cervical lesions (NCCLs) using optical coherence tomography ...(OCT).
After treatment with NCCLs, cross-sectional images of the lesion parts of the sample were non-invasively acquired and analyzed. The surface smoothness between tooth and resin, resin and cemento-enamel junction, and the presence bubble inside resin was confirmed. In addition, using an algorithm that distinguishes between resin and dental structure based on OCT cross-sectional images, we quantitatively analyzed the amount of resin used in treating NCCLs and acquired 3D images.
The inner structure of the resin in each sample was checked, and the presence of bubbles was confirmed. In addition, the resin sections were separated from the tomographic images acquired by OCT to visualize 3D images. The volume of resin used in the treatment part of each NCCLs samples was quantitatively analyzed as 3.7216 ∼ 14.889 mm3.
OCT is able to measure not only the surface abrasion provided by existing intraoral scanner, but also the size and depth location of interal bubbles, which is distinctive advantage of our method. Based on our results, OCT is a significant tool for qualitative and quantitative analysis of dental NCCLs treatment before and after treatment.
The study used OCT, a non-destructive diagnostic, to reveal the structure of the resin and the location and size of bubbles after NCCLs treatment. These findings could be golden standard in determining the prognosis of NCCLs treatment.
Aim
To investigate if crystallinity and ultrastructure are modified when cervical dentine is treated with four different nanogels‐based solutions for remineralizing purposes.
Methodology
Experimental ...nanogels based on polymeric nanoparticles (NPs) and zinc, calcium or doxycycline‐loaded NPs were applied to citric acid etched dentine to facilitate the occlusion of tubules and the mineralization of the dentine surface. Dentine surfaces were studied by X‐ray diffraction and transmission electron microscopy through selected area diffraction and bright‐field imaging.
Results
Crystals at the dentine surface were identified as hydroxyapatite with the highest crystallographic maturity and crystallite size in dentine treated with Zn‐NPs‐based gel. Texture increased in all samples from 24 h to 7 days, except in dentine surfaces treated with Zn‐NPs gel. Polyhedral, plate‐like and drop‐like shaped apatite crystals constituted the bulk of minerals in dentine treated with Zn‐NPs gel, after 7 days. Polymorphic, cubic and needle‐like shaped crystals distinguished minerals, with more amorphous characteristics in dentine treated with Ca‐NPs gel after 7 days than that found when Zn‐NPs were applied. Doxycycline‐NPs produced the smallest crystallites with poor crystallinity, maturity and chemical stability.
Conclusions
Crystalline and amorphous phases of newly formed hydroxyapatite were described in both types of dentine treated with Zn‐NPs as well as Ca‐NPs gels with multiple shapes of crystallites. Crystal shapes ranged from rounded/drop‐like or plate‐like crystals to needle‐like or polyhedral and cubic apatite appearance.
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