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Concept: Endodontics

169

BACKGROUND: Shape of the dental root canal is highly patient specific. Automated identification methods of themedial line of dental root canals and the reproduction of their 3D shape can be beneficial forplanning endodontic interventions as severely curved root canals or multi-rooted teeth may posetreatment challenges. Accurate shape information of the root canals may also be used bymanufacturers of endodontic instruments in order to make more efficient clinical tools. METHOD: Novel image processing procedures dedicated to the automated detection of the medial axis of theroot canal from dental micro-CT and cone-beam CT records are developed. For micro-CT, the 3Dmodel of the root canal is built up from several hundred parallel cross sections, using imageenhancement, histogram based fuzzy c-means clustering, center point detection in the segmentedslice, three dimensional inner surface reconstruction, and potential field driven curve skeletonextraction in three dimensions. Cone-beam CT records are processed with image enhancement filtersand fuzzy chain based regional segmentation, followed by the reconstruction of the root canalsurface and detecting its skeleton via a mesh contraction algorithm. RESULTS: The proposed medial line identification and root canal detection algorithms are validated on clinicaldata sets. 25 micro-CT and 36 cone-beam-CT records are used in the validation procedure. Theoverall success rate of the automatic dental root canal identification was about 92% in bothprocedures. The algorithms proved to be accurate enough for endodontic therapy planning. CONCLUSIONS: Accurate medial line identification and shape detection algorithms of dental root canal have beendeveloped. Different procedures are defined for micro-CT and cone-beam CT records. Theautomated execution of the subsequent processing steps allows easy application of the algorithms inthe dental care. The output data of the image processing procedures is suitable for mathematicalmodeling of the central line. The proposed methods can help automate the preparation and design ofseveral kinds of endodontic interventions.

Concepts: Dimension, Root canal, Endodontic therapy, Endodontics, Curve, Analytic geometry, Canal, Canal+

169

BACKGROUND: Recent studies reported on the very complex morphology of the pulp system in equine cheek teeth. The continuous production of secondary dentine leads to distinct age-related changes of the endodontic cavity. Detailed anatomical knowledge of the dental cavities in all ages is required to explain the aetiopathology of typical equine endodontic diseases. Furthermore, data on mandibular and maxillary pulp systems is in high demand to provide a basis for the development of endodontic therapies. However, until now examination of the pulp cavity has been based on either sectioned teeth or clinical computed tomography. More precise results were expected by using micro-computed tomography with a resolution of about 0.1 mm and three-dimensional reconstructions based on previous greyscale analyses and histological verification. The aim of the present study was to describe the physiological configurations of the pulp system within a wide spectrum of tooth ages. RESULTS: Maxillary teeth: All morphological constituents of the endodontic cavity were present in teeth between 4 and 16 years: Triadan 06s displayed six pulp horns and five root canals, Triadan 07-10s five pulp horns and four root canals and Triadan 11s seven pulp horns and four to six root canals. A common pulp chamber was most frequent in teeth <=5 years, but was found even in a tooth of 9 years. A large variety of pulp configurations was observed within 2.5 and 16 years post eruption, but most commonly a separation into mesial and distal pulp compartments was seen. Maxillary cheek teeth showed up to four separate pulp compartments but the frequency of two, three and four pulp compartments was not related to tooth age (P > 0.05). In Triadan 06s, pulp horn 6 was always connected to pulp horns 1 and 3 and root canal I. In Triadan 11s, pulp horns 7 and 8 were present in variable constitutions. Mandibular teeth: A common pulp chamber was present in teeth up to 15 years, but most commonly seen in teeth <=5 years. A segmented pulp system was found in 72% of the investigated teeth. Segmentation into separate mesial and distal pulp compartments was most commonly present. Pulp horn 4 coalesced either with the mesial pulp horns 1 and 3 or with the distal pulp horns 2 and 5. CONCLUSIONS: Details of the pulpar anatomy of equine cheek teeth are provided, supporting the continuous advancement in endodontic therapy. Numerous individual configurations of the pulp system were obtained in maxillary cheek teeth, but much less variability was seen in mandibular cheek teeth.

Concepts: Teeth, Tooth, Dental caries, Root canal, Endodontic therapy, Endodontics, Dentin, Animal anatomy

68

Root canal therapy (RCT) represents a standard of treatment that addresses infected pulp tissue in teeth and protects against future infection. RCT involves removing dental pulp comprised of blood vessels and nerve tissue, decontaminating residually-infected tissue through biomechanical instrumentation, and root canal obturation using a filler material to replace the space that was previously comprised of dental pulp. Gutta percha (GP) is typically used as the filler material as it is malleable, inert, and biocompatible. While filling the root canal space with GP is the standard of care for endodontic therapies, it has exhibited limitations including leakage, root canal reinfection, and poor mechanical properties. To address these challenges, clinicians have explored the use of alternative root filling materials other than GP. Among the classes of materials that are being explored as novel endodontic therapy platforms, nanodiamonds (NDs) may offer unique advantages due to their favorable properties, particularly for dental applications. These include versatile faceted surface chemistry, biocompatibility, and their role in improving mechanical properties, among others. This study developed a ND-embedded GP (NDGP) that was functionalized with amoxicillin, a broad-spectrum antibiotic commonly used for endodontic infection. Comprehensive materials characterization confirmed improved mechanical properties of NDGP over unmodified GP. In addition, digital radiography and micro-computed tomography imaging demonstrated that obturation of root canals with NDGP could be achieved using clinically-relevant techniques. Furthermore, bacterial growth inhibition assays confirmed drug functionality of NDGP functionalized with amoxicillin. This study demonstrates a promising path towards NDGP implementation in future endodontic therapy for improved treatment outcomes.

Concepts: Biomaterial, Materials science, Teeth, Root canal, Endodontic therapy, Endodontics, Gutta-percha

27

External cervical resorption is the loss of dental hard tissue as a result of odontoclastic action; it usually begins on the cervical region of the root surface of the teeth. This case report demonstrates an external cervical resorption in a maxillary central incisor of a 24-year-old male patient. After surgical intervention and root canal treatment, the resorption was subsequently sealed with mineral trioxide aggregate. The 18 months follow-up demonstrates no pathological changes on clinical and radiographic examination. This case report presents a treatment strategy that might improve the healing outcomes for patients with external cervical resorption.

Concepts: Hospital, Mammal, Teeth, Endodontic therapy, Endodontics, Incisor, Maxillary central incisor, Maxillary lateral incisor

27

AIM: (i) To assess the impact of primary root canal treatment on the perceived quality of life amongst a cohort of Jordanian patients, (ii) to assess this cohort’s satisfaction of their primary root canal treatment, and (iii) to evaluate the association of the level of training and experience of clinicians with these two parameters. METHODOLOGY: A systematic random sample of 302 subjects was selected from patients who attended undergraduate, graduate and specialty clinics of Jordan University of Science and Technology. Participants were interviewed before and two weeks after completion of root canal treatment. The study instrument included the Oral Health Impact Profile questionnaire (Dugas et al. 2002) and seven semantic differential scales. Data analyses included descriptive statistics and nonparametric analyses. RESULTS: More than 90% of subjects reported improvements in the sense of taste, pain, eating, altering food temperature, self-consciousness, waking up during sleep, interruption of meals, difficulty to relax and difficulty to sleep after root canal treatment. There was no significant difference in terms of improvement amongst patients treated by specialists, graduate students or undergraduate students. The overall semantic differential score of intraoperative pain, pleasantness, chewing ability and general satisfaction was about 8. Satisfaction of root canal treatment by specialists was higher in terms of time involved, intraoperative pain, pleasantness and general satisfaction than those treatments by undergraduate students. Patients treated by specialist were least satisfied with the treatment cost compared to those patients treated by graduate or undergraduate students. CONCLUSIONS: The impact of root canal treatment on the quality of life was apparent. Satisfaction with root canal treatment approximates 8 on the semantic differential scale with preference for specialists over dental students.

Concepts: Psychometrics, Root canal, Endodontic therapy, Endodontics, Educational stages, Postgraduate education, Bachelor's degree, Semantic differential

27

A case of endodontic treatment of a mandibular first premolar exhibiting a total of four distinct root canals and four apical foramina is described. This occurrence in mandibular first premolar has rarely been reported in the endodontic literature. Endodontic treatment that considers the anatomic variation of root canal morphology is important to ensure a favorable healing outcome, and its identification could be enhanced by careful examination using a dental operating microscope. Obturation of root canals using a warm vertical compaction technique with a highly-radiopaque root canal sealer, such as AH Plus, after careful ultrasonic activated irrigation with ethylenediaminetetraacetic acid might allow the flow of sealer into the narrowed but unprepared part of the canal. This offers valuable adjuncts for the successful negotiation of calcified main canals, thereby facilitating optimum chemo-mechanical debridement of the root canal system.

Concepts: Anatomy, Root canal, Endodontic therapy, Endodontics, Dentistry, Premolar, Mandibular second premolar, Mandibular first premolar

26

The aim of the study was to assess the penetrability of two endodontic sealers (AH Plus and MTA Fillapex) into dentinal tubules, submitted to endodontic treatment and subsequently to endodontic retreatment. Thirty ex vivo incisors were prepared using ProTaper rotary system up to F3 instrument and divided in three groups according to the endodontic sealer used for root canal filling: AH Plus (AHP), MTA Fillapex (MTAF), and control group (CG) without using EDTA previously to the root canal filling. Rhodamine B dye (red) was incorporated to the sealers in order to provide the fluorescence which will enable confocal laser scanning microscopy (CLSM) assessment. All specimens were filled with gutta-percha cones using the lateral compaction technique. The specimens were submitted to endodontic retreatment using ProTaper Retreatment system, re-prepared up to F5 instruments and filled with gutta-percha cones and the same sealer used during endodontic retreatment. Fluorescein dye (green) was incorporated to the sealer in order to distinguish from the first filling. The roots were sectioned 2 mm from the apex and assessed by CLSM. No difference was found between the two experimental groups (P > 0.05). On the other hand, in the control group the sealers were not capable to penetrate into dentinal tubules after endodontic treatment (P > 0.05). In retreatment cases, none of the sealers were able to penetrate into dentin tubules. It can be concluded that sealer penetrability is high during endodontic treatment. However, MTA Fillapex and AH Plus do not penetrate into dentinal tubules after endodontic retreatment. Microsc. Res. Tech., 2014. © 2014 Wiley Periodicals, Inc.

Concepts: Assessment, Root canal, Endodontic therapy, Endodontics, Fluorescein, Dentin, Dentistry, Rhodamine

25

While pulp regeneration using tissue engineering strategy has been explored for over a decade, successful regeneration of pulp tissues in a full-length human root with a one-end seal that truly simulates clinical endodontic treatment has not been achieved. To address this challenge, we designed and synthesized a unique hierarchical growth factor-loaded nanofibrous microsphere scaffolding system. In this system, vascular endothelial growth factor (VEGF) binds with heparin and is encapsulated in heparin-conjugated gelatin nanospheres, which are further immobilized in the nanofibers of an injectable poly(L-lactic acid) (PLLA) microsphere. This hierarchical microsphere system not only protects the VEGF from denaturation and degradation, but also provides excellent control of its sustained release. In addition, the nanofibrous PLLA microsphere integrates the extracellular matrix-mimicking architecture with a highly porous injectable form, efficiently accommodating dental pulp stem cells (DPSCs) and supporting their proliferation and pulp tissue formation. Our in vivo study showed the successful regeneration of pulp-like tissues that fulfilled the entire apical and middle thirds and reached the coronal third of the full-length root canal. In addition, a large number of blood vessels were regenerated throughout the canal. For the first time, our work demonstrates the success of pulp tissue regeneration in a full-length root canal, making it a significant step toward regenerative endodontics.

Concepts: Angiogenesis, Blood vessel, Vascular endothelial growth factor, Cellular differentiation, Regeneration, Root canal, Endodontic therapy, Endodontics

25

Mineral trioxide aggregate (MTA) is a calcium silicate-based cement (CSC) commonly used in endodontic procedures involving pulpal regeneration and hard tissue repair, such as pulp capping, pulpotomy, apexogenesis, apexification, perforation repair, and root-end filling. Despite the superior laboratory and clinical performance of MTA in comparison with previous endodontic repair cements, such as Ca(OH)2 , MTA has poor handling properties and a long setting time. New CSC have been commercially launched and marketed to overcome the limitations of MTA. The aim of the present review was to explore the available literature on new CSC products, and to give evidence-based recommendations for the clinical use of these materials. Within the limitations of the available data in the literature regarding the properties and performance of the new CSC, the newer products could be promising alternatives to MTA; however, further research is required to support this assumption.

Concepts: Present, Time, Calcium, Calcium carbonate, Endodontic therapy, Endodontics, Portland cement, Cement

24

The aim of this study was to perform an overview of literature search strategies in systematic reviews (SRs) published in 2 endodontic journals, Journal of Endodontics and International Endodontic Journal.

Concepts: Thought, Endodontics, Journal, Journal of Endodontics