Cemento-dentinal Junction Research Articles

Dental characteristics of patients with four different types of skeletal dysplasias.

Skeletal dysplasia (SD) comprises more than 450 separate disorders. We hypothesized that their dental features would be distinctive and investigated the tooth characteristics of four patients with different SDs. Four SD patients with molecularly confirmed diagnoses, Pt-1 acromicric dysplasia, Pt-2 hypophosphatasia and hypochondroplasia, Pt-3 cleidocranial dysplasia, and Pt-4 achondroplasia, were recruited. A tooth from each patient was evaluated for mineral density (micro-computerized tomography), surface roughness (surface profilometer), microhardness, mineral contents (energy-dispersive X-ray), and ultrastructure (scanning electron microscopy and histology), and compared with three tooth-type matched controls. Pt-1 and Pt-3 had several unerupted teeth. Pt-2 had an intact-root-exfoliated tooth at 2years old. The lingual surfaces of the patients' teeth were significantly smoother, while their buccal surfaces were rougher, than controls, except for Pt-1's buccal surface. The patients' teeth exhibited deep grooves around the enamel prisms and rough intertubular dentin. Pt-3 demonstrated a flat dentinoenamel junction and Pt-2 had an enlarged pulp, barely detectable cementum layer, and ill-defined cemento-dentinal junction. Reduced microhardnesses in enamel, dentin, and both layers were observed in Pt-3, Pt-4, and Pt-1, respectively. Pt-1 showed reduced Ca/P ratio in dentin, while both enamel and dentin of Pt-2 and Pt-3 showed reduced Ca/P ratio. Each SD has distinctive dental characteristics with changes in surface roughness, ultrastructure, and mineral composition of dental hard tissues. In this era of precision dentistry, identifying the specific potential dental problems for each patient with SD would help personalize dental management guidelines.

Cemental tears: challenges in the diagnosis and management of an unusual finding associated with rapid localized periodontal and peri-radicular bone loss

A cemental tear is a rare form of root surface fracture whereby a fragment of cementum partially or completely detaches from the root surface at the cemento-dentinal junction or within the body of cementum. Tears are most prevalent in incisors and lead to the breakdown of periodontal issues. Owing to challenges involved in diagnosis, cemental tears may be misdiagnosed because associated clinical and radiographic features closely resemble those seen in vertical root fractures, periodontal abscesses and endo-periodontal lesions. If incorrectly diagnosed, inappropriate and delayed management may result in treatment failure and tooth loss. CPD/Clinical Relevance: Correct diagnosis and timely management of cemental tears can prevent further destruction of periodontal tissues, improve treatment outcomes and increase tooth survival.

The Structure of Cemento-dentinal Junction in Mandibular Deciduous Second Molars and Permanent First Molars in Egyptian Populations (Scanning Electron Microscope Study)

The Structure of Cemento-dentinal Junction in Mandibular Deciduous Second Molars and Permanent First Molars in Egyptian Populations (Scanning Electron Microscope Study)

Cemental tear: Literature review, proposed classification and recommendations for treatment.

Cemental tears are an important condition of relevance to Endodontics but are often overlooked. A cemental tear is the partial or complete detachment of the cementum from the cemento-dentinal junction or along the incremental line within the body of cementum. The limited attention received is most likely due to the limited awareness amongst dental professionals and challenges in accurately diagnosing them, resulting in misdiagnosis and erroneous treatment. The aim of this review is to describe the: (i) epidemiology and predisposing factors; (ii) clinical, radiographic and histological features and (iii) the clinical management and treatment outcomes of cemental tear. The review included 37 articles published in English that comprised eight observational studies and 29 case reports. The prevalence of cemental tears was reported to be lower than 2%; whilst the incidence remains unknown. Internal factors due to the inherent structural weakness of cementum and its interface with the dentine, and external factors that are associated with stress have been proposed as the two mechanisms responsible for the development and propagation of cemental tears. Predisposing factors that have been implicated were tooth type, gender, age, previous root canal treatment, history of dental trauma, occlusal trauma and excessive occlusal force; however, evidence is limited. Common clinical and radiographic manifestations of cemental tears resemble the presentations of primary endodontic diseases, primary periodontal diseases and combined endodontic-periodontal lesions. Clinical management tended to focus on complete removal of the torn fragments and periodontal treatment, often combined with regenerative treatment. In this article, a new classification for cemental tears is developed that consists of classes 0 to 6 and stages A, B, C and D based on the: (i) location and accessibility of the torn cemental fragment; (ii) the pattern and extension of the associated bony defect in relation to the root length and (iii) the number of root surface/s affected by the cemental tear/s and the associated bony defect. Recommendations for treatment strategies are also provided and linked to the classification to aid in streamlining the process of treatment decision making.

English

The objectives of root canal treatment are elimination of microorganisms, removal of pulpal remnants, removal of debris, and shaping of the root canal system so that it may be obturated. The most important step in endodontic therapy is canal preparation which can be achieved by accurate working length determination. Working length determines the extent of placing the instruments into the canal, it affects the degree of pain and discomfort which the patient will experience post treatment and it plays an important role in the success of the treatment if placed within correct limits. The cementodentinal junction, where the pulp tissue changes into the apical tissue, is the ideal physiologic apical limit of WL because at this point healing is supposed to be optimal, and the wound to the periapical tissues is minimal.The apical constriction is however, histological and is impossible to locate clinically or radiographically. There are several methods of determining working length which include radiographical methods, digital tactile sense, apical periodontal sensitivity, paper point method and electronic apex locators. The requirements of an ideal method for determining working length include rapid location of the apical constriction in all pulpal conditions, easy measurement, rapid periodic monitoring and confirmation, patient and clinician comfort, minimal radiation to the patient; ease of use in special patients; and cost effectiveness. To achieve the highest degree of accuracy in working length determination, a combination of several methods should be used. This article reviews the different methods to determine WL and their clinical implications. KEY WORDS Working Length, Apex Locator, Radiographic Method.

The effect of fluorosis on human teeth under light microscopy: A cross-sectional study.

Background:Fluoride is needed for the normal development of bone and teeth; in high levels, it affects developing teeth and bone. Dental fluorosis (DF) is caused by ingestion of excess fluoride mainly through drinking water.Aim:The present study aims to observe and understand the histological changes of fluorosed teeth under light microscope (LM).Materials and Methods:Teeth which were indicated for extractions for orthodontic or periodontal problems were selected. Thirty extracted teeth were selected with varying degrees of DF based on modified Dean's fluorosis index. Ground sections of these teeth were prepared and the sections were studied under binocular LM. Photomicrographs were taken under high power objective using 15 megapixels Nikon camera.Results and Conclusion:Qualitative histologic changes in different grades of fluorosed teeth were evaluated in enamel, dentin, cementum and between their junctions. Fluoride interacts with enamel in both mineral phases and organic macromolecules by strong ionic and hydrogen bonds resulting in incomplete crystal growth at prism peripheries. This presents as hypomineralization of enamel and dentin, increased interglobular dentin, increased secondary curvatures and changes in cementum such as diffuse cementodentinal junction and increased thickness of Tomes’ granular layer. Changes in the structure of the teeth with Dean's index below 2 and teeth with Dean's index of 2 and above were compared using Chi-square test. P value was found to be highly significant being 0.00047. Many of the features of dental fluorosis seen in the present study under light microscope are comparable to those results studied under specialized microscopes.

Treatment of cemental tear associated with periapical lesion using regenerative surgery; A case report

Purpose: Cemental tear is a specific type of root surface fracture characterized by a complete separation of a cemental fragment along the cementodentinal junction or a partial split within the cementum along an incremental line. It is suggested to be a factor for periodontal or periapical tissue destruction. The aim of this study is to present a diagnosis and treatment of cemental tear associated with periapical lesion with root canal treatment and regenerative periodontal surgery. Treatments: A 60-year-old male who had a history of sports trauma on the mandibular right central incisor about 10 years ago presented with apical cemental tear. Clinical examination showed a slightly dark yellowish discoloration and sinus tract that was located on the apical labial mucosa. The mobility and percussion were also assessed on the diseased tooth and recorded as Miller°phis Class II and tenderness to percussion. The probing depth was within the normal limit (<3 mm). Radiographic examination revealed a radiolucent lesion at the apical area and extended to distal aspect of the tooth along the fragment of cemental tear. After root canal treatment, periapical surgery was performed. The bony defect was exposed and then the detached root fragment was removed. Apical root resection and retrograde filling with Mineral Trioxide Aggregate (MTA) were accomplished and the bony defect was filled with deproteinized bovine bone mineral (DBBM) and covered with biodegradable collagen membrane. Results: After 9-month follow-up, healing of the mandibular right central incisor was uneventful and no swelling, purulence or pain was revealed in the associated area. Probing pocket depth was favorably stable, and the tooth mobility was decreased to the Miller's Class I. Conclusions: Apical cemental tear associated periapical lesion could be successfully treated with removal of the detached cementum in combination with apical surgery and GTR procedure.

Fibrous architecture of cementodentinal junction in disease: A scanning electron microscopic study.

Background:The cementodentinal junction (CDJ) forms a biological and structural link between cementum and dentin. This biological link is regarded as a distinct tissue in its own right. Certain important proteins responsible for periodontal regeneration are said to be present in this tissue. Few studies have described the structure and composition of this layer by light and electron microscopy. Scanning electron microscopic studies pertaining to CDJ in health and disease are few and documentation of periodontal pathological changes of CDJ is unclear. In the first phase of our study, the collagenous architecture of CDJ of healthy teeth has been reported.Aim:The objective of this study is to observe and report periodontal pathological changes in the fibrous or collagenous architecture of CDJ of periodontitis-affected teeth and discuss the probable clinical implications of CDJ in disease.Materials and Methods:Twenty periodontitis-affected teeth were collected and processed for observing under a scanning electron microscope.Results:The results are as follows: Increased width of interface at CDJ in periodontitis samples (7.1 μ) compared to that of healthy samples; fewer areas of fiber intermingling at CDJ in periodontitis samples as compared to healthy samples; frequent detachment of cementum from dentin during sodium hydroxide maceration of samples.Conclusion:It may be inferred from results that there is a possibility of a definite weakening of CDJ in periodontally affected root surfaces and we believe that clinical procedures such as scaling and root planning may have a detrimental effect on the cementodentinal attachment of periodontally involved root surfaces.

Scanning electron microscopic observations of fibrous structure of cemento-dentinal junction in healthy teeth.

The cemento-dentinal junction (CDJ) is a structural and biologic link between cementum and dentin present in the roots of teeth. Conflicting reports about the origin, structure and composition of this layer are present in literature. The width of this junctional tissue is reported to be about 2-4 μm with adhesion of cementum and dentin by proteoglycans and by collagen fiber intermingling. The objective of this study is to observe and report the fibrous architecture of the CDJ of healthy tooth roots. A total of 15 healthy teeth samples were collected, sectioned into halves, demineralized in 5% ethylenediaminetetraacetic acid, processed using NaOH maceration technique and observed under a scanning electron microscope. The CDJ appeared to be a fibril poor groove with a width of 2-4 µm. Few areas of collagen fiber intermingling could be appreciated. A detailed observation of these tissues has been presented.

The anatomy of the root apex: A review and clinical considerations in endodontics

Studies on the anatomy of the root apex are an area of interest to the endodontist; they have reported that the position of the apical constriction, apical foramen and the cemento-dentinal junction varies across the tooth types. These anatomical apical landmarks are considered extension limits for root canal instrumentation and filling. Achieving an optimum working length is thought essential for successful root canal treatment, so adopting any of these landmarks is associated with certain risks and benefits. The variability in the position of the apical constriction and apical foramen, for example, complicates their clinical detection, while the cemento-dentinal junction is a histological landmark that cannot be detected clinically. The radiographic apex does not always coincide with the anatomic apex of the tooth. The pre-operative status of the pulp must be considered while obtaining the working length. Most prognostic studies agree that extending the root filling to within 2-3 mm of the radiographic apex is associated with favorable treatment outcomes.

Three-rooted premolar analyzed by high-resolution and cone beam CT

The aim of this study was to analyze the variations in canal and root cross-sectional area in three-rooted maxillary premolars between high-resolution computed tomography (μCT) and cone beam computed tomography (CBCT). Sixteen extracted maxillary premolars with three distinct roots and fully formed apices were scanned using μCT and CBCT. Photoshop CS software was used to measure root and canal cross-sectional areas at the most cervical and the most apical points of each root third in images obtained using the two tomographic computed (CT) techniques, and at 30 root sections equidistant from both root ends using μCT images. Canal and root areas were compared between each method using the Student t test for paired samples and 95 % confidence intervals. Images using μCT were sharper than those obtained using CBCT. There were statistically significant differences in mean area measurements of roots and canals between the μCT and CBCT techniques (P < 0.05). Root and canal areas had similar variations in cross-sectional μCT images and became proportionally smaller in a cervical to apical direction as the cementodentinal junction was approached, from where the area then increased apically. Although variation was similar in the roots and canals under study, CBCT produced poorer image details than μCT. Although CBCT is a strong diagnosis tool, it still needs improvement to provide accuracy in details of the root canal system, especially in cases with anatomical variations, such as the three-rooted maxillary premolars.

Clinical Fracture Site, Morphologic and Histopathologic Characteristics of Cemental Tear: Role in Endodontic Lesions

IntroductionClinical research regarding the clinical and histopathologic characteristics of cemental tear is limited in the endodontic literature. The objective of this study was to evaluate the morphology, apicocoronal location, and the histologic characteristics of cemental tear. MethodsThe material was collected during 1987–2009 and consisted of 54 teeth that were presented with cemental tears by histologic examination. To investigate the atypical prospects among the groups of each variable, a series of the Poisson χ2 goodness-of-fit tests were conducted to test for a fit of a discrete, uniform distribution. ResultsCemental tear occurred mainly in incisors (74.1%), proximal root surfaces (79.6%), male patients (74.1%), and patients older than 60 years (72.3%). They were noted often in the middle third of root (45.3%), but 41.5% of cemental tears were noted over the apical region. The morphology of cemental tear was either small/thin piece-shaped (77.4% cases) involving 1 root surface or U-shaped (22.6%) involving >1 root surface. The size of cemental tear had an average length of 3.8 mm, width of 2.2 mm, and thickness of 0.9 mm. The separations of cemental tears occurred at cementodentinal junction (77.6%) relative to cementum (22.4%). The adhered soft tissue was either granulation tissue (92.3%) or cyst (7.7%). ConclusionsCemental tear mainly occurs in incisors of male and older persons. It is also popularly noted in the apical region mimicking an endodontic lesion and some with cystic change. Clinically, endodontists should know this disease entity, make accurate early diagnosis, and totally remove the cemental tear during apical surgery to improve the prognosis.

Harvesting cementum from root surface: A new paradigm in the study of cementum and the cemento-dentinal junction

Cementum and the cemento-dentinal junction has been a subject of debate for long. Here, the author has demonstrated an unreported technique to harvest cementum from the surface of the root surface of human teeth and also reviewed literature with respect to the cemento-dentinal junction. The method was based on the conclusion that the tissue between radicular dentin and cementum is an enamel-like hypermineralized tissue. The demineralization protocol reported demineralises the hypermineralized intermediate tissue and this dissolution unlocks the junction releasing the cementum from the radicular dentin surface. The cementum is separated as sock or in shreds and the observations reported.

Evaluation of canal preparation for apical sealing with various Ni-Ti rotary instruments

Objectives: The aim of this study was to evaluate the various NiTi rotary instruments regarding their ability to provide a circular apical preparation. Materials and Methods: 50 single canal roots were selected, cut at the cementodentinal junction and the coronal 1/3 of the canals was flared using Gates Glidden burs. Samples were randomly divided into 5 experimental groups of 10 each. In group I, GT files, Profile 04 and Quantec #9 and #10 files were used. In Group II Lightspeed was used instead of Quantec. In Group III, Orifice shaper, Profile .06 series and Lightspeed were used. In Group IV, Quantec #9 and #10 files were used instead of Lightspeed. In Group V, the GT file and the Profile .04 series were used to prepare the entire canal length. All tooth samples were cut at 1 mm, 3 mm and 5 mm from the apex and were examined under the microscope. Results: Groups II and III (Lightspeed) showed a more circular preparation in the apical 1mm samples than the groups that used Quantec (Group I & IV) or GT files and Profile .04 series.(Group V)(p

EVALUATION OF THE ACCURACY OF TWO APEX LOCATORS AND RADIOVISIOGRAPHY-AN IN VITRO STUDY

Determination of an accurate working length is one of the most critical steps of Endodontic therapy. The cleaning, shaping and obturation of root canal system cannot be accomplished accurately unless working length is determined precisely. Locating the appropriate apical position always has been a challenge in clinical Endodontics. The cementodentinal junction (CDJ), where the pulp tissue changes into the apical tissue, is the most ideal physiologic apical limit of the working length. However, the CDJ and apical constricture do not always coincide, particularly in senile teeth as a result of cementum deposition, which alters the position of the minor diameter. In an attempt to measure the working length to a value that almost coincides with the actual length or anatomic length and to overcome all the errors that could occur due to the limitation of the present techniques used, electronic apex locators with their inherent capacity to minimize the errors and the simplicity of the technique involved in the calibration of working length seems to be an important break through in the field of Endodontics. Modern electronic apex locators can determine this position with accuracies of greater than 90% but still have some limitations. Knowledge of apical anatomy, prudent use of radiographs and the correct use of an electronic apex locator will assist practitioners to achieve predictable results.

Histomorphometric Study of the Root Apex of Mandibular Premolar Teeth: An Attempt to Correlate Working Length Measured with Electronic and Radiograph Methods to Various Anatomic Positions in the Apical Portion of the Canal

One aim of this study was to attempt to relate the position of the cementodentinal junction (CDJ) and the apical constriction to that of the apical foramen in mandibular premolars, as well as to measure the canal diameter at these various points. Another aim was to evaluate how electronic working length determination by Root ZX and radiographic method of working length determination correlated to the location of these various positions. The results showed that CDJ was detected at average distance of 0.3 mm from apical foramen with average canal diameter of 0.32 mm, whereas the apical constriction was detected at average distance from apical foramen of 1.2 mm with canal diameter of 0.22 mm. There was a statistically significant difference between file-tip position from apical foramen in group I working length measured by Root ZX and group II working length measured radiographically. Also this significant difference was found between file-tip position in both groups and CDJ and apical constriction. The average canal diameter at 0.5, 1, and 1.5 mm from apical foramen was 0.33 ± 0.11, 0.28 ± 0.06, and 25 ± 0.05 mm, respectively.

An immunohistochemical study of the attachment mechanisms in different kinds of adhesive interfaces in teeth and alveolar bone of the rat

This study was designed to examine the histological and immunohistochemical nature of different kinds of adhesive interfaces in the rat molar region under identical experimental conditions and to discuss the structural and functional similarities between these adhesive interfaces. Four kinds of adhesive interfaces - an initial attachment layer for principal fibers on the developing alveolar bone surface, a reattachment layer for principal fibers on resorbed alveolar bone surface, cement lines on the alveolar bone surface unrelated to the principal fibers, and the cemento-dentinal junction - were examined in 25-d-old male Wistar rats. Routine histological staining, immunohistochemical staining for bone sialoprotein and osteopontin, and digestion tests with trypsin were conducted. The adhesive interfaces showed very similar histological and immunohistochemical features: they were intensely hematoxylin-stainable, deficient in collagen fibrils, and rich in bone sialoprotein and osteopontin. After trypsin treatment the four adhesive interfaces had lost immunoreactivity to bone sialoprotein and osteopontin, and the two adjacent tissue parts held together finally separated at the adhesive interfaces. The above findings suggest that (i) the different types of adhesive interfaces in the rat molar region have a common structure in that they are filled with highly accumulated bone sialoprotein and osteopontin and deficient in collagen fibrils; (ii) accumulated bone sialoprotein and osteopontin are closely associated with the adhesion at the interfaces; and (iii) the adhesive interfaces have a similar developmental process.

Apical Microleakage of Different Luting Agents in Endodontically Treated Teeth Restored with Para-Post System

ABSTRACTEndodontically treated teeth are known to present a higher risk of biomechanical failure than vital teeth. Complete obturation of the root canal system to the cementodentinal junction is assumed to be an important goal in endodontic treatment. The microleakage is determined today by many in vivo and in vitro techniques such as; staining, measurement by scanning electron microscope, bacterial activity, decay, air pressure, chemical agents, markers, neutron activation analysis, radioisotope, ionisation, autoradiography, and reversible radioactive adsorption and thermal cyclus application. The purpose of this study was to compare the apical leakage with using the biomolecular characteristics of the methylene blue technique in root canals obturated with a stainless-steel post system (ParaPost System) cemented with zinc-policarboxilate cement, glass-ionomer cement and resin cement. Fifty mandibular first premolar teeth with straight root canals, anatomically similar root segments (root lengths 17 mm.), and fully developed apices, extracted for periodontal reasons, were selected and divided into 5 groups of 10 each. Analysis of variance (ANOVA) was used to determine whether significiant differences existed between the means of the different groups. Multiple comparisons and rankings were done using Duncan's multiple range test. The negative controls and positive controls all leaked significantly more than all of the experimental groups. Glass ionomer cement had significantly less microleakage than zinc-policarboxilate cement. Composite resin (self-cured) cement had significant more microleakage than all of the cements at (p<0.001).

Determination of two different types of cellular cementogenesis in rat molars: A histological and immunohistochemical study

To elucidate the attachment mechanism of dentin and cellular cementum, developing and developed cellular cementum of rat molars was examined by light microscopy. Routine histological staining, immunohistochemical staining for bone sialoprotein (BSP) and osteopontin (OPN), and digestion tests with trypsin were conducted. Two different types of cellular cementogenesis were established, one on the mesial (type I cementogenesis) and one on the distal sides (type II cementogenesis) of the examined roots. In the type I cementogenesis a thin initial cementum layer, which was fibril-poor, hematoxylin-stained, and immunopositive for BSP and OPN, appeared on the mineralized dentin. With cellular cementogenesis, the layer became the cemento-dentinal junction. The cementum mineralization did not precede the dentin mineralization. After trypsin treatment the cemento-dentinal junction lost immunoreactivity for BSP and OPN and the cementum was detached from the dentin. In the type II cementogenesis the cellular cementum formed directly on the predentin without the initial cementum layer and the cementum mineralization preceded the dentin mineralization. Cemental and predentinal fibrils appeared to intermingle, as the cemento-dentinal junction was indiscernible by any staining. Trypsin treatment did not cause cementum detachment. The findings of the present study suggest that: (1) The type I cementogenesis requires the intervening initial cementum to bind cementum and dentin and to induce the cementum mineralization. (2) In the type II cementogenesis the cemento-dentinal attachment depends on fibril intermingling and the cementum mineralization advances apically and very rapidly, probably producing mineralization foci. (3) The formation of the initial cementum depends on the speed of the cementogenesis in the apical direction.

Fiber Optic Fluorescence Microprobe for Endodontic Diagnosis

Successful endodontic therapy requires total debridement as well as complete obturation of the root canal to the cemento-dentinal junction. The goal of this study was to investigate the feasibility of using quantitative fluorescence spectroscopy for the detection and localization of pathological dentin, pulpal remnants, and microorganisms within the root canal. Specific aims were to identify: 1) characteristic excitation/emission spectra for healthy dentin, decayed dentin, enamel, and pulp; 2) the potential of specific spectral data for differentiating between these tissues; and 3) the potential of spectral data for detecting the presence and identifying four common endodontic pathogens. Fluorescence spectra were determined in the tissues of permanent human teeth, extirpated healthy and necrotic pulps, and four endodontic pathogens. Excitation/emission spectra were collected at 366 nm, 405 nm, and 440 nm excitation. Marked differences in spectral signatures between the different tissues under investigation were observed. We postulate that the differences in fluorescence spectra of decayed vs. healthy dentin are due to the loss of mineralized tissue components and increased organic presence and water in these tissues. Pulpal tissue showed distinctly different fluorescence spectra from healthy and decayed dentin, providing a basis for differentiating between tissue categories. Each bacterial species demonstrated distinct spectral emission patterns.