The extended finite element method in endodontics: A scoping review and future directions for cyclic fatigue testing of nickel-titanium instruments

OBJECTIVES

The present study reviews the current literature regarding the utilization of the extended finite element method (XFEM) in clinical and experimental endodontic studies and the suitability of XFEM in the assessment of cyclic fatigue in rotary endodontic nickel-titanium (NiTi) instruments.

MATERIAL AND METHODS

An electronic literature search was conducted using the appropriate search terms, and the titles and abstracts were screened for relevance. The search yielded 13 hits after duplicates were removed, and four studies met the inclusion criteria for review.

RESULTS

No studies to date have utilized XFEM to study cyclic fatigue or crack propagation in rotary endodontic NiTi instruments. Challenges such as modelling material inputs and fatigue criteria could explain the lack of utilization of XFEM in the analysis of mechanical behavior in NiTi instruments.

CONCLUSIONS

The review showed that XFEM was seldom employed in endodontic literature. Recent work suggests potential promise in using XFEM for modelling NiTi structures.

Accuracy of Magnetic Resonance Imaging in Clinical Endodontic Applications: A Systematic Review

INTRODUCTION

The development of dedicated coils and new magnetic resonance imaging (MRI) sequences has led to an increase in image resolution and a reduction in artifacts. Consequently, numerous studies have demonstrated the utility of MRI as a nonionizing alternative to cone-beam computed tomographic imaging. The aim of this systematic review was to evaluate the accuracy of MRI in clinical applications in endodontics.

METHODS

A literature search was conducted using PubMed, Embase, Scopus, and Web of Science. The inclusion criteria encompassed studies evaluating MRI applications in endodontics, covering tooth and root canal anatomy, root canal working length, pulp vitality and regeneration, the effect of caries on dental pulp, guided endodontics, periapical lesions, and root cracks/fractures. The selected studies examined both ex vivo and in vivo human teeth using clinical MRI units. Two researchers independently screened the studies, applied the eligibility criteria, and assessed the potential risk of bias using the revised QUADAS-2 tool (Bristol Medical School, University of Bristol, UK).

RESULTS

A total of 18 studies were included in this systematic review, demonstrating that the use of MRI has a high diagnostic value in endodontics. In the evaluation of tooth and root canal anatomy, pulp vitality and regeneration, the effect of caries on dental pulp, periapical lesions, and root cracks/fractures, MRI's accuracy is comparable to or even higher than reference standards such as cone-beam computed tomographic imaging, micro-computed tomographic imaging, and histology.

CONCLUSIONS

MRI has high potential accuracy for diagnosing various clinical endodontic tasks, except for root canal length, size of caries, and periapical lesion dimensions, which are overestimated in MRI.

Robot-Assisted and Haptic-Guided Endodontic Surgery: A Case Report

There has been a significant increase in robot-assisted dental procedures in the past decade, particularly in the area of robot-assisted implant placement. The objective of this case report was to assess the initial use of the Yomi Robot's assistance and haptic guidance during endodontic microsurgery. The robot was used during the osteotomy and root-end resection of the first and second upper left premolars. The report aims to inform clinicians of the initial implementation of this cutting-edge technology in endodontics and its potential to enhance endodontic microsurgery. The Yomi Robot was used in performing osteotomy and root-end resection during apical surgery in a patient presenting with symptomatic upper left first and second premolars. The treatment procedure was decided after clinical examination, chart data, and radiographic examinations, which showed periapical lesions on both premolars, taking into consideration the failed endodontic retreatment on the first premolar, the post and ceramic coronal restorations on both teeth, and the desire of the patient to save them. The Yomi Robot system provides auditory, visual, and physical guidance to clinicians during surgery while using a cone-beam computed tomography scan for precision planning with greater accuracy and minimized potential for human error. Further studies are needed to prepare a protocol for robotic-guided procedures in endodontics.

Comparing accuracy in guided endodontics: dynamic real-time navigation, static guides, and manual approaches for access cavity preparation - an in vitro study using 3D printed teeth

OBJECTIVES

To assess root canal localization accuracy using a dynamic approach, surgical guides and freehand technique in vitro.

MATERIALS AND METHODS

Access cavities were prepared for 4 different 3D printed tooth types by 4 operators (n = 144). Deviations from the planning in angle and bur positioning were compared and operating time as well as tooth substance loss were evaluated (Kruskal-Wallis Test, ANOVA). Operating method, tooth type, and operator effects were analyzed (partial eta-squared statistic).

RESULTS

Angle deviation varied significantly between the operating methods (p < .0001): freehand (9.53 ± 6.36°), dynamic (2.82 ± 1.8°) and static navigation (1.12 ± 0.85°). The highest effect size was calculated for operating method (ηP²=0.524), followed by tooth type (0.364), and operator (0.08). Regarding deviation of bur base and tip localization no significant difference was found between the methods. Operating method mainly influenced both parameters (ηP²=0.471, 0.379) with minor effects of tooth type (0.157) and operator. Freehand technique caused most substance loss (p < .001), dynamic navigation least (p < .0001). Operating time was the shortest for freehand followed by static and dynamic navigation.

CONCLUSIONS

Guided endodontic access may aid in precise root canal localization and save tooth structure.

CLINICAL RELEVANCE

Although guided endodontic access preparation may require more time compared to the freehand technique, the guided navigation is more accurate and saves tooth structure.

Expert consensus on digital guided therapy for endodontic diseases

Digital guided therapy (DGT) has been advocated as a contemporary computer-aided technique for treating endodontic diseases in recent decades. The concept of DGT for endodontic diseases is categorized into static guided endodontics (SGE), necessitating a meticulously designed template, and dynamic guided endodontics (DGE), which utilizes an optical triangulation tracking system. Based on cone-beam computed tomography (CBCT) images superimposed with or without oral scan (OS) data, a virtual template is crafted through software and subsequently translated into a 3-dimensional (3D) printing for SGE, while the system guides the drilling path with a real-time navigation in DGE. DGT was reported to resolve a series of challenging endodontic cases, including teeth with pulp obliteration, teeth with anatomical abnormalities, teeth requiring retreatment, posterior teeth needing endodontic microsurgery, and tooth autotransplantation. Case reports and basic researches all demonstrate that DGT stand as a precise, time-saving, and minimally invasive approach in contrast to conventional freehand method. This expert consensus mainly introduces the case selection, general workflow, evaluation, and impact factor of DGT, which could provide an alternative working strategy in endodontic treatment.

Guided Endodontic Surgery: A Narrative Review

Background and objectives: Endodontic surgery has evolved over the last two decades. The use of state-of-the-art guided endodontic surgical procedures produces a predictable outcome in the healing of lesions of endodontic origin. The main objective of this review paper is to define and characterize guided surgical endodontics as well as its benefits and drawbacks by reviewing the most recent relevant scientific literature. Methods: A literature search was conducted using multiple databases comprising of MEDLINE (via PubMed), EMBASE, and Web of Science. The terms used for the search were ‘guided endodontics’, ‘surgical endodontics’, and ‘endodontic microsurgery’. Results: In total, 1152 articles were obtained from the analysis of the databases. Unrelated articles from the available full text of 388 articles were excluded. A total of 45 studies were finally included in the review. Conclusions: Surgical-guided endodontics is a relatively new area of study that is still maturing. It has many applications such as root canal access and localization, microsurgical endodontics, endodontic retreatment, and glass fiber post removal. Additionally, it does not matter how experienced the operator is; the procedure can be completed for the patient in less time and provides greater accuracy and safety than conventional endodontics.

Accuracy of Endodontic Access Cavities Performed Using an Augmented Reality Appliance: An In Vitro Study

INTRODUCTION

The purpose of this study was to compare and contrast the accuracy of endodontic access cavities created using an augmented reality appliance to those performed using the conventional technique.

MATERIALS AND METHODS

60 single-rooted anterior teeth were chosen for study and randomly divided between two study groups: Group A-endodontic access cavities created using an augmented reality appliance as a guide (n = 30) (AR); and Group B-endodontic access cavities performed with the manual (freehand) technique (n = 30) (MN). A 3D implant planning software was used to plan the endodontic access cavities for the AR group, with a cone-beam computed tomography (CBCT) and 3D intraoral surface scan taken preoperatively and subsequently transferred to the augmented reality device. A second CBCT scan was taken after performing the endodontic access cavities to compare the planned and performed endodontic access for accuracy. Therapeutic planning software and Student's t-test were used to analyze the cavities at the apical, coronal, and angular levels. The repeatability and reproducibility of the digital measurement technique were analyzed using Gage R&R statistical analysis.

RESULTS

The paired t-test found statistically significant differences between the study groups at the coronal (p = 0.0029) and apical (p = 0.0063) levels; no statistically significant differences were found between the AR and MN groups at the angular (p = 0.6596) level.

CONCLUSIONS

Augmented reality devices enable the safer and more accurate performance of endodontic access cavities when compared with the conventional freehand technique.

Endodontic length measurements using cone beam computed tomography with dedicated or conventional software at different voxel sizes

The aim of this study is to investigate the accuracies and the agreements of the 3D Endo software, conventional CBCT software Romexis Viewer at three voxel sizes, and the EAL ProPex Pixi in endodontic length measurements. Three hundred and twenty-nine root canals in 120 intact human extracted molars were accessed. The actual lengths (AL) and electronic lengths (EL) were measured using the ruler and electronic apex locator (EAL), respectively. Teeth were scanned using the CBCT at different voxel sizes (0.075, 0.10, and 0.15 mm). Root canal lengths were measured using 3D Endo with proposed length (3D-PL) by software, corrected length (3D-CL), Romexis Viewer. The Fisher's exact test, paired t-test and Bland-Altman plots were calculated to detect the agreements of the four methods with AL measurements. The ProPex Pixi measurements obtained the highest accuracy in the range of ± 0.5 mm. There was agreement between the 3D-PL and the 3D-CL with AL measurements at voxel size of 0.15 mm and at voxel size of 0.10 mm, respectively. The CBCT Romexis Viewer measurements agreed with AL at three voxel sizes. The conventional CBCT measurements using Romexis Viewer and dedicated software did not reach to the 100% accuracy in the range of ± 0.5 mm.

Filling ability of three variants of the single-cone technique with bioceramic sealer: a micro-computed tomography study

The present study evaluated the quality of single-cone root canal fillings with bioceramic (BC) sealer using three different techniques by means of micro-computed tomography (micro-CT). The canals of 30 extracted single-rooted permanent teeth were shaped with R40 Reciproc blue files and filled with the single-cone technique (SCT). BioRoot RCS BC sealer was placed inside the canals with one of the following master cones: R40 cone to working length (RWL, n = 10); R40 cone trimmed 1 mm short of working length (RWL-1, n = 10); non-standardized gutta-percha cone to working length (NSWL, n = 10). A quantitative and qualitative micro-CT analysis assessed the filling quality and internal/external voids formation. Collected data underwent statistical analysis by multivariate one-way analysis of variance (α = 0.05). In all groups, the voids were minimal and prevalently external. The NSWL and RWL-1 groups had increased sealer ratios in the whole canal and the apical canal portion, respectively. The lowest amounts of voids were found in the RWL group; the void volumes were slightly greater in the RWL-1 mm and NSWL groups, especially at the apical level. Two alternative SCTs showed satisfactory filling ability, uniform distribution of the BC sealer, and a minimally increased voids formation compared to the standard SCT with dedicated cone. The two tested alternative SCTs could take advantage of the beneficial characteristics of the BC sealer, which evenly filled the endodontic space, ideally sealing both the major and the accessory communications with the periodontium.

Technical note: surgical guide for computer-aided endodontic surgery

INTRODUCTION

CBCT combined to intra-oral scansion are the means to build an endodontic surgical guide to perform an easier and safer access to the apex in endodontic micro-surgery. .

METHODS

A 38-year-old woman presented chronic apical periodontitis, which involved the three roots of 16 that was treated by endodontic therapy several years ago elsewhere. The palatine channel was retreated, the mesio- and disto- buccal roots were instead treated with apicoectomy. A surgical template was printed by a 3D printer to obtain greater precision in the surgical access.

CONCLUSIONS

Endodontic microsurgery has evolved over the years. New tools have been introduced to improve therapy, even if the basic principles have not changed. In fact, according to the literature, it is necessary to cut at least 3 mm of root to be sure of eliminating the anatomical variations and the accessory channels. Several Authors have devoted themselves to creating an endodontic surgical template, some in vitro and others in vivo. The present paper introduces a new method that allows a more conservative osteotomy and greater precision the surgical access. Further investigation are needed to test and improve the effectiveness of the treatment but this technique seems very promising because it is less invasive for the patient and simplifies the work for the dentist who can perform micro-surgery in an easier and faster way.

Enhanced mechanical properties and biosafety evaluation of surface-modified fiberglass-reinforced resin-based composite piles

The purpose of this study is to analyze various surface grafting modifications of fiberglass-reinforced resin based composite piles. In addition, the effects of surface modifications of fiberglass-reinforced resin piles in terms of biosafety and mechanical strength were studied. According to different surface treatment methods, the fiberglass was divided into five groups (A-E): a blank control group, a KH570 processing group, a KH570 processing+Bis-GMA grafting 1 h group, a KH570 processing+Bis-GMA grafting 3 h group and a KH570 processing+Bis-GMA grafting 7 h group. All surface-treated materials were characterized using scanning electron microscope, thermogravimetric analyses and Fourier transform infrared spectrum and mechanical testing using a universal mechanical tester. The biosafety was evaluated by cell viability experiments and repeated oral toxicity tests and Ames tests. The Bis-GMA grafting modification further enhanced the mechanical properties of resin piles. By increasing the grafting time, the grafting effect and mechanical properties were further enhanced. The surfaces grafted for 7 h (Group E) remarkably improved the mechanical properties (flexural strength ~696.24 MPa; flexural load ~185.67N). The graft modifications improved the mechanical properties of fiber pile resin-based materials. The prolonged grafting time further improved the mechanical properties corresponding to enhanced grafting and the formation of a stable interface between fibers and the resin matrix. The surface-modified dental resin-based fiber did not show any signs of toxicity, cytotoxicity or mutagenicity, suggesting the potential biological safety of these materials in the clinical practice.

Direct and Indirect Restorations for Endodontically Treated Teeth: A Systematic Review and Meta-analysis, IAAD 2017 Consensus Conference Paper

PURPOSE

The primary objective of this systematic review was to compare treatment outcomes of direct and indirect permanent restorations in endodontically treated teeth, and provide clinical suggestions for restoring teeth after endodontic treatment.

MATERIALS AND METHODS

Electronic databases (Medline, EMBASE, CENTRAL) and gray literature were screened for articles in English that reported on prospective and retrospective clinical studies of direct or indirect restorations after endodontic treatment with an observation period of at least 3 years. Primary outcomes were determined to be short-term (≤ 5 years) and medium-term (> 5 and ≤ 10 years) survival. Secondary outcomes included restorative and endodontic success of restored teeth. The quality of included studies and risk of bias were assessed using Cochrane Collaboration's tool for RCTs (randomized controlled trials), the Newcastle-Ottawa Scale for cohort studies, and the Agency for Healthcare Research and Quality (AHRQ) methodology checklist for cross-sectional studies. The GRADE system was used for assessing collective strength of the overall body of evidence.

RESULTS

Of 2547 screened articles, only 9 (2 RCTs, 3 retrospective cohort studies, 3 cross-sectional studies) met the inclusion criteria, and 8 studies were used in the meta-analysis. In general, indirect restorations (mostly full crowns) showed higher 5-year survival (OR 0.28, 95% CI 0.19-0.43, p < 0.00001) and 10-year survival (OR 0.20, 95% CI 0.12-0.31, p < 0.00001) than direct restorations. However, there was no statistical difference in short-term (≤ 5-years) restorative success (OR 0.32, 95% CI 0.05-2.12, p = 0.24) and endodontic success (OR 0.88, 95% CI 0.72-1.08, p = 0.22).

CONCLUSIONS

Based on current evidence, there is a weak recommendation for indirect restorations to restore endodontically treated teeth, especially for teeth with extensive coronal damage. Indirect restorations using mostly crowns have higher short-term (5-year) and medium-term (10-year) survival than do direct restorations using composite or amalgam (GRADE quality of evidence: low to moderate), but no difference in short-term (≤ 5 years) restorative success (low quality) and endodontic success (very low quality). There is a need for high-quality clinical trials, especially well-designed RCTs.

[Regenerative endodontics after front tooth trauma. A case report]

In the context of tooth trauma, mostly the maxillary central front teeth are involved, whereby their roots are in some cases still in the developing stage (immature). Depending on the type of trauma, a necrosis of the pulp is the consequence or at least foreseeable. In order to preserve such a tooth, an endodontic therapy is inevitable. The disadvantage of conventional endodontic therapy methods of immature teeth (apexification, apexogenesis) is the root growth stop. Alternatively, the regeneration/revascularisation of the dental pulp (RP) was suggested, that allows a further root growth. The aim of this case report is to present the procedure of a RP-therapy and to suggest a step-by-step manual.

Bioactive endodontic materials for everyday use: a review

Bioceramic materials are at the forefront of modern dentistry. Bioactive bioceramic endodontic materials promote pulpal and periapical tissue healing and are easy to use. Dentists can choose among many endodontic materials, depending on their needs. This article highlights the major differences among commercially available bioactive tricalcium silicate bioceramics, commonly known as mineral trioxide aggregate materials, to enable dentists to make appropriate decisions in the selection of these materials.

Antibiotic and Analgesic Prescription Patterns among Dentists or Management of Dental Pain and Infection during Endodontic Treatment

OBJECTIVE

The aim of this study was to determine prescription patterns of antibiotics and analgesics among dentists in the management of dental pain and infection for medically healthy patients undergoing endodontic management.

MATERIALS AND METHODS

This descriptive cross-sectional survey was based on a structured questionnaire. The questionnaire collected data on age, gender, years of experience, and the qualifications of dentists. Feedback on prescription patterns for antibiotics and analgesics was collected for a number of clinical scenarios. Participants' choices regarding the type, dose, and duration of antibiotics/analgesics were recorded. Completed questionnaires were analyzed using the Statistical Package for Social Sciences (SPSS; version 24) to determine relationships between prescription patterns, age, gender, and educational qualification.

RESULTS

Of the 227 participants surveyed, 190 (83.7%) did not prescribe antibiotics for patients complaining of severe pain. There were significant associations between age and years of experience and antibiotic prescription for pain management (p = 0.035 and 0.04, respectively). Of the participants, 199 (87.7%) never prescribed antibiotics for reversible pulpitis with normal periapical area; there was a statistical significance in relation to gender (p = 0.044). Amoxicillin 500 mg was prescribed most of the time (51.5%). Diclofenac K (50 mg) was prescribed by 41% of the participants, while 39.2% of the participants very often prescribed ibuprofen (600 mg).

CONCLUSION

Most dentists prescribed analgesics and antibiotics as recommended, but more education on the proper use of these medicines is needed for dentists and patients.

Middle mesial canal of the permanent mandibular first molars: an anatomical challenge directly related to the outcome of endodontic treatment

To effectively clean and shape the mandibular permanent first molars it is mandatory to understand in detail their complex internal anatomy. The middle mesial canal is an additional canal located between the usual mesiobuccal and mesiolingual canals in the mesial root of mandibular first molars. The incidence of the middle mesial canal, its relationship with main canals of the mesial root and the possibility for it to be negotiated is an important practical issue in endodontics. To identify the presence of this canal is mandatory. Accordingly, a modified endodontic access, the use of the operating microscope and periapical radiographs in two different horizontal projections are indicated to enhance the long-term favorable outcome of the endodontic treatment.

A Comparative study for the management of Peri-radicular Pathosis by Conventional Root Canal Therapy and Non Instrumental Endodontic Therapy

Non-surgical endodontics is one of the realities in modern endodontics globally which is a highly sophisticated specialized technical clinical procedure to conserve the teeth. Lesion Sterilized Tissue Repair (LSTR) is an alternative of conventional non-surgical endodontics (C-RCT) considered being a valuable adjunct to the treatment of infected root canal. This cross sectional prospective study was carried out in the department of Conservative Dentistry & Endodontics, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from January 2002 to January 2003. This study involved 100 cases of symptomatic endodontically involved teeth with peri radicular pathosis treated by non-surgical method (C-RCT) & (LSTR therapy) in multi-visit technique and immediate and long-term clinical and radiological follow-up done for 24 months. The result revealed complete disappearance of sinus tract 46(92%) in C-RCT and 35(70%) in LSTR therapy group and success in C-RCT was 88% and in LSTR therapy as 86% after 24 months follow-up by clinical and radiological evaluation. So, it can be concluded that non-surgical approach in the management of periradicular pathosis by C-RCT and LSTR therapy was found safe, effective and practical method of treatment of an endodontically involved tooth.

Platelet-rich fibrin: a boon in regenerative endodontics

Research into regenerative dentistry has contributed momentum to the field of molecular biology. Periapical surgery aims at removing periapical pathology to achieve complete wound healing and regeneration of bone and periodontal tissue. Regenerative endodontic procedures are widely being added to the current armamentarium of pulp therapy procedures. The regenerative potential of platelets has been deliberated. Platelet-rich fibrin (PRF) is a wonderful tissue-engineering product and has recently gained much popularity due its promising results in wound healing bone induction. The features of this product are an attribute of platelets which, after cellular interactions, release growth factors and have shown application in diverse disciplines of dentistry. This paper is intended to shed light onto the various prospects of PRF and to provide clinical insight into regenerative endodontic therapy.

Effect of bioactive dental adhesive on periodontal and endodontic pathogens

The objectives of this study were to: (1) develop a new bioactive dental bonding agent with nanoparticles of amorphous calcium phosphate and dimethylaminohexadecyl methacrylate for tooth root caries restorations and endodontic applications, and (2) investigate biofilm inhibition by the bioactive bonding agent against eight species of periodontal and endodontic pathogens for the first time. Bonding agent was formulated with 5 % of dimethylaminohexadecyl methacrylate. Nanoparticles of amorphous calcium phosphate at 30 wt% was mixed into adhesive. Eight species of biofilms were grown on resins: Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Parvimonas micra, Enterococcus faecalis, Enterococcus faecium. Colony-forming units, live/dead assay, biomass, metabolic activity and polysaccharide of biofilms were determined. The results showed that adding dimethylaminohexadecyl methacrylate and nanoparticles of amorphous calcium phosphate into bonding agent did not decrease dentin bond strength (P > 0.1). Adding dimethylaminohexadecyl methacrylate reduced the colony-forming units of all eight species of biofilms by nearly three orders of magnitude. The killing efficacy of dimethylaminohexadecyl methacrylate resin was: P. gingivalis > A. actinomycetemcomitans > P. intermedia > P. nigrescens > F. nucleatum > P. micra > E. faecalis > E. faecium. Dimethylaminohexadecyl methacrylate resin had much less biomass, metabolic activity and polysaccharide of biofilms than those without dimethylaminohexadecyl methacrylate (P < 0.05). In conclusion, a novel dental adhesive was developed for root caries and endodontic applications, showing potent inhibition of biofilms of eight species of periodontal and endodontic pathogens, and reducing colony-forming units by three orders of magnitude. The bioactive adhesive is promising for tooth root restorations to provide subgingival margins with anti-periodontal pathogen capabilities, and for endodontic sealer applications to combat endodontic biofilms.

[Application of PBL combined with SP method in during-course practice of endodontics for undergraduate dental students]

PURPOSE

To apply problem-based learning (PBL) combined with standardized patients(SP) in during-course practice of endodontics for undergraduate dental students, in order to improve the teaching quality.

METHODS

One hundred and four undergraduate dental students of China Medical University School of Stomatology were randomly divided into 2 groups, 52 students in each group. One group were taught with PBL combined with SP while the other group with lecture-based learning (LBL) alone. The teaching effect was measured with examination and questionnaire survey. The data were analyzed by Student's t test using SPSS 11.5 software package.

RESULTS

Students in PBL combined with SP group was better than LBL group in case analysis, didactic tests, practical tests and total scores, and there was significant difference between the two groups (P<0.05). LBL group was better than PBL combined with SP group in basic theoretical knowledge scores, and there was significant difference between the two groups (P<0.05). SP and PBL combined with SP method were welcomed by undergraduate dental students.

CONCLUSIONS

The abilities of undergraduate dental students can be improved by PBL combined with SP in different aspects. PBL combined with SP achieves satisfactory teaching effect, and can be applied in during-course practice of endodontics to undergraduate dental students.

[Analysis of the key points in the micro-endodontic treatment]

Micro-endodontic treatment refers to the microscope-assisted endodontic treatment techniques. The microscope offers a stereoscopic, enlarged image under great magnification and illumination at a comfortable working position. It will greatly promote the precision and improve the outcomes of endodontic treatment through enhancing the ability to detect the complexity of the root canal system of teeth that probably cannot be seen by the naked eyes, remove the infectious substances in root canal more efficiently, provide a tight root canal obturation and carry out effective retreatment procedures. The requirements of micro-endodontic treatment are different from the conventional root canal therapy carried out without microscope due to the complicated structure of the microscope. In order to make the use of microscope easier, it is of great importance to learn how to adjust the position of the operator and the patient, preset the angle of objective lens and the eyepiece, select the proper magnification and instruments, practice eye-hand cooperation under the microscope, etc. The purpose of this article was to analyze the key points in the applications of the microscope in endodontic treatment by reviewing the literature together with the author's clinical experience.

Surgical Endodontics in Dogs: A Review

Surgical endodontic therapy (apical surgery) is a treatment alternative aimed at removing periapical inflammatory tissue followed by apical resection and retro-filling of the root canal. These procedures are performed through a trans-osseous approach. Terminology pertinent to this article include: apical (periapical) curettage – a surgical procedure to remove diseased tissue from the alveolar bone in the apical region of a pulpless tooth; apical cyst – a cyst in bone at the apex of a pulpless tooth. It is believed that such cysts arise after the death of the pulp from noxious physical, chemical, or bacterial stimulation of epithelial rests of Malassez; apicoectomy (apical resection) – amputation of the apical portion of the root and removal of soft tissue in the bone; epithelial rests of Malassez – cords, strands, or clusters of ectodermal cells in the periodontal ligament (or sometimes alveolar bone) derived from remnants of Hertwig's epithelial root sheath. These cells frequently begin proliferating when inflammation occurs in the periodontal ligament and are believed to be responsible for the genesis of the epithelial lining of apical cysts.

[Overall digitalization: leading innovation of endodontics in big data era]

In big data era, digital technologies bring great challenges and opportunities to modern stomatology. The applications of digital technologies, such as cone-beam CT(CBCT), computer aided design,(CAD)and computer aided manufacture(CAM), 3D printing and digital approaches for education , provide new concepts and patterns to the treatment and study of endodontic diseases. This review provides an overview of the application and prospect of commonly used digital technologies in the development of endodontics.

[Use of Cone Beam Computed Tomography in endodontics: rational case selection criteria]

AIM

To present rational case selection criteria for the use of CBCT (Cone Beam Computed Tomography) in endodontics.

MATERIALS AND METHODS

This article reviews the literature concerning the benefits of CBCT in endodontics, alongside its radiation risks, and present case selection criteria for referral of endodontic patients to CBCT.

RESULTS

Up to date, the expected ultimate benefit of CBCT to the endodontic patient is yet uncertain, and the current literature is mainly restricted to its technical efficacy. In addition, the potential radiation risks of CBCT scan are stochastic in nature and uncertain, and are worrying especially in pediatric patients.

CONCLUSIONS

Both the efficacy of CBCT in supporting the endodontic practitioner decision making and in affecting treatment outcomes, and its long term potential radiation risks are yet uncertain. Therefore, a cautious rational decision making is essential when a CBCT scan is considered in endodontics. Risk-benefit considerations are presented.

Regenerative endodontics--Creating new horizons

Trauma to the dental pulp, physical or microbiologic, can lead to inflammation of the pulp followed by necrosis. The current treatment modality for such cases is non-surgical root canal treatment. The damaged tissue is extirpated and the root canal system prepared. It is then obturated with an inert material such a gutta percha. In spite of advances in techniques and materials, 10%-15% of the cases may end in failure of treatment. Regenerative endodontics combines principles of endodontics, cell biology, and tissue engineering to provide an ideal treatment for inflamed and necrotic pulp. It utilizes mesenchymal stem cells, growth factors, and organ tissue culture to provide treatment. Potential treatment modalities include induction of blood clot for pulp revascularization, scaffold aided regeneration, and pulp implantation. Although in its infancy, successful treatment of damaged pulp tissue has been performed using principles of regenerative endodontics. This field is dynamic and exciting with the ability to shape the future of endodontics. This article highlights the fundamental concepts, protocol for treatment, and possible avenues for research in regenerative endodontics.

Magnification devices for endodontic therapy

BACKGROUND

After the introduction of microsurgical principles in endodontics involving new techniques for root canal treatment, there has been a drive to enhance the visualisation of the surgical field. It is important to know if the technical advantages for the operator brought in by magnification devices such as surgical microscopes, endoscopes and magnifying loupes, are also associated with advantages for the patient in terms of improvement of clinical and radiographic outcomes. This version updates the review published in 2009.

OBJECTIVES

To evaluate and compare the effects of endodontic treatment performed with the aid of magnification devices versus endodontic treatment without magnification devices. We also aimed to compare the different magnification devices used in endodontics with one another.

SEARCH METHODS

The following electronic databases were searched: the Cochrane Oral Health Group Trials Register (to 13 October 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2015, Issue 9), MEDLINE via OVID (1946 to 13 October 2015) and EMBASE via OVID (1980 to 13 October 2015). We searched the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the WHO Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We considered all randomised controlled trials (RCTs) and quasi-randomised controlled trials comparing endodontic therapy performed with versus without one or more magnification devices, as well as randomised and quasi-randomised trials comparing two or more magnification devices used as an adjunct to endodontic therapy.

DATA COLLECTION AND ANALYSIS

We conducted screening of search results independently and in duplicate. We obtained full papers for potentially relevant trials. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis.

MAIN RESULTS

No trials met the inclusion criteria for this review.

AUTHORS' CONCLUSIONS

No article was identified in the current literature that satisfied the criteria for inclusion. It is unknown if and how the type of magnification device affects the treatment outcome, considering the high number of factors that may have a significant impact on the success of endodontic surgical procedure. This should be investigated by further long-term, well-designed RCTs that conform to the CONSORT statement (www.consort-statement.org/).

Applications of Light Amplification by Stimulated Emission of Radiation (Lasers) for Restorative Dentistry

Light amplification by stimulated emission of radiation (laser) has been used widely in a range of biomedical and dental applications in recent years. In the field of restorative dentistry, various kinds of lasers have been developed for diagnostic (e.g. caries detection) and operative applications (e.g. tooth ablation, cavity preparation, restorations, bleaching). The main benefits for laser applications are patient comfort, pain relief and better results for specific applications. Major concerns for using dental lasers frequently are high cost, need for specialized training and sensitivity of the technique, thereby compromising its usefulness particularly in developing countries. The main aim of this paper is to evaluate and summarize the applications of lasers in restorative dentistry, including a comparison of the applications of lasers for major restorative dental procedures and conventional clinical approaches. A remarkable increase in the use of lasers for dental application is expected in the near future.

Techniques and materials used by general dentists during endodontic treatment procedures: Findings from The National Dental Practice-Based Research Network

BACKGROUND

Little is known about which materials and techniques general dentists (GDs) use during endodontic procedures. The objectives were to quantify GDs' use of specific endodontic tools, quantify inappropriate use, and ascertain whether inappropriate use is associated with GDs' practice characteristics.

METHODS

GDs in The National Dental Practice-Based Research Network reported in a questionnaire materials and techniques they use during endodontic procedures.

RESULTS

Among eligible GDs, 1,490 (87%) participated. Most (93%; n = 1,383) used sodium hypochlorite to irrigate. The most commonly used sealers were zinc oxide eugenol (43%) and resin (40%), followed by calcium hydroxide (26%). Most (62%; n = 920) used a compaction obturation technique; 36% (n = 534) used a carrier-based method. Most (96%; n = 1,423) used gutta-percha as a filler; 5% used paste fillers. Few used irrigants (n = 46), techniques (n = 49), or fillers (n = 10) that investigators classified as inappropriate.

CONCLUSIONS

GDs use a broad range of endodontic techniques and materials, often adapting to newer technologies as they become available. Few GDs use tools that the investigators classified as inappropriate.

PRACTICAL IMPLICATIONS

GDs use many types of endodontic techniques and materials, but only a small percentage of them are inappropriate.

The confidence of undergraduate dental students when performing root canal treatment and their perception of the quality of endodontic education

AIM

This article aims to gain understanding into the perception of undergraduate dental students in terms of their confidence and competence at performing root canal treatment and their perception of the quality of endodontic education.

METHODS

An online questionnaire was distributed to all 3rd, 4th and 5th year dental students at Cardiff University via their academic e-mail addresses. The questionnaire utilised both scaled response and open questions to gain an insight into undergraduate opinion.

RESULTS

Out of a possible 208 students, 98 responses were obtained (response rate = 47%). Perception of competence and confidence were significantly greater amongst the more senior year groups (P < 0.01). However, 49% (n = 38) of participants did not feel competent performing root canal treatment on anterior, single-rooted teeth, whilst 74% (n = 70) did not feel competent performing root canal treatment on posterior, multirooted teeth. Free comments from participants indicated that this was due to a lack of clinical experience. Approximately, 80% of participants ranked education in endodontics at Cardiff University as ≤5 on a Likert scale (1 = inadequate to 10 = good), indicating that improvement was required. Improvements that were suggested by the students included the provision of further information within lectures, a broader range of lecturers, an increased number of shorter, more organised practical sessions, additional training equipment, greater supervision and online reference guides to root canal treatment.

CONCLUSION

Enhancing undergraduate education in endodontics is necessary to increase students' perception of their confidence and competence when performing root canal treatment.

Cone beam CT for dental and maxillofacial imaging: dose matters

The widespread use of cone-beam CT (CBCT) in dentistry has led to increasing concern regarding justification and optimisation of CBCT exposures. When used as a substitute to multidetector CT (MDCT), CBCT can lead to significant dose reduction; however, low-dose protocols of current-generation MDCTs show that there is an overlap between CBCT and MDCT doses. More importantly, although the 3D information provided by CBCT can often lead to improved diagnosis and treatment compared with 2D radiographs, a routine or excessive use of CBCT would lead to a substantial increase of the collective patient dose. The potential use of CBCT for paediatric patients (e.g. developmental disorders, trauma and orthodontic treatment planning) further increases concern regarding its proper application. This paper provides an overview of justification and optimisation issues in dental and maxillofacial CBCT. The radiation dose in CBCT will be briefly reviewed. The European Commission's Evidence Based Guidelines prepared by the SEDENTEXCT Project Consortium will be summarised, and (in)appropriate use of CBCT will be illustrated for various dental applications.

Calcium Hydroxide Dressing Influences the Obturation of Simulated Lateral Canals

AIM

The aim of this study was to investigate the influence of calcium hydroxide dressing on the filling of simulated lateral canals by different obturation techniques.

MATERIALS AND METHODS

Sixty single-root-premolars were instrumented. Simulated lateral canals were drilled on each third of the roots. The teeth were divided into four groups: no dressing and obturation by lateral condensation technique (G1), dressing with calcium hydroxide and obturation by lateral condensation technique (G2), no dressing and obturation by hybrid technique (G3) and, dressing with calcium hydroxide and obturation by hybrid technique (G4). The teeth were maintained at 37°C in 100% humidity for 7 days, and obturation techniques were performed. Radiographs were taken and filled or unfilled lateral canals were counted. Data were analyzed using analysis of variance (ANOVA) followed by Tukey's test (a = 5%).

RESULTS

The hybrid technique filled large number of lateral canals as compared to lateral condensation technique, regardless the use of intracanal medication (p < 0.05). Calcium hydroxide decreased the number of lateral canals filled for both lateral and hybrid techniques (p < 0.05). Significant differences were observed when comparing the number of filled and unfilled lateral canals in the same root third of each group (p < 0.05).

CONCLUSION

Regardless the obturation technique, calcium hydroxide dressing reduced the penetration of filling material in simulated lateral canals.

CLINICAL SIGNIFICANCE

The persistence of calcium hydroxide residues reduces the penetration of filling material in simulated lateral canals, possibly representing a potential cause of failure in the future.

Mandibular first molar with six root canals: a rare entity

Recently, there has been an ongoing trend of case reports that highlight the presence of more than four root canals in mandibular first molars. This tendency warns clinicians to be more prudent when dealing with mandibular first molars requiring endodontic treatment. Moreover, radiographic examination should be taken as a clue providing tool rather than as an absolute guide to anatomy and its associated aberrances. This case reports the successful non-surgical endodontic management of a mandibular first molar with six root canal systems with three canals in the mesial root and three in the distal root. The classification of root canal systems found in this case was Sert and Bayirli type XV in both the roots. After non-surgical endodontic treatment, the tooth was restored definitively with a resin composite core followed by porcelain fused to the metal crown. This case adds to the library of previously reported cases of mandibular first molars with six root canals and further emphasises on the importance of rare morphological deviations that may occur in the mandibular first molars.

Cone beam computed tomography updated technology for endodontic diagnosis

Cone beam computed tomography has gained acceptance in the endodontic community for assistance with diagnosis, treatment, and evaluation of outcomes. This article reviews a multitude of applications, from basic principles to clinical applications, using specific cases and supporting literature to demonstrate the benefits for both the specialist and general practitioner.

[A tooth or an implant--literature based decision making]

The common use of dental implants in the daily practice led to a profound change in the available treatment strategies. The option of replacing a diagnosed doubtful tooth with an implant has become widely accepted and often used. The prognosis systems in use today are based on the three major disciplines: endodontics, periodontics and prosthodontics. Combining these three may impair and bias the decision making process and increase the tendency to base it on subjective clinical experience and personal preference. Reading and reviewing the relevant literature gives no clear tool for use. Root canal treatment is considered a highly predictable treatment procedure and a treated tooth is affected mainly by the quality and type of the fabricated restoration and the risk of caries. Periodontal treatment followed by a suitable maintenance regimen will likely allow long term tooth survival. When comparing the success rates of natural teeth rehabilitation versus implant supported restorations, it appears that with implants an additional treatment is demanded along the years. This coincides with the fact that to date there is no consensus regarding the extent of perimplantitis and perimucositis that is to be expected around a restored implant. In addition, a peri implant tissue problem or a failure of a dental implant may prove to be more challenging than a failure of a tooth. It is important to remember that a dental implant is made to substitute a missing tooth and it is a treatment modality with known and clear indications for rehabilitation of an edentulous space. The aim of this paper is to review and discuss the various aspects of whether to maintain a compromised or a doubtful tooth or to prefer a treatment modality using dental implants. In conclusion it is advised here, to incorporate the discussed issues in the decision making process towards the most suitable treatment plan.

Sonochemical and high-speed optical characterization of cavitation generated by an ultrasonically oscillating dental file in root canal models

Ultrasonically Activated Irrigation makes use of an ultrasonically oscillating file in order to improve the cleaning of the root canal during a root canal treatment. Cavitation has been associated with these oscillating files, but the nature and characteristics of the cavitating bubbles were not yet fully elucidated. Using sensitive equipment, the sonoluminescence (SL) and sonochemiluminescence (SCL) around these files have been measured in this study, showing that cavitation occurs even at very low power settings. Luminol photography and high-speed visualizations provided information on the spatial and temporal distribution of the cavitation bubbles. A large bubble cloud was observed at the tip of the files, but this was found not to contribute to SCL. Rather, smaller, individual bubbles observed at antinodes of the oscillating file with a smaller amplitude were leading to SCL. Confinements of the size of bovine and human root canals increased the amount of SL and SCL. The root canal models also showed the occurrence of air entrainment, resulting in the generation of stable bubbles, and of droplets, near the air-liquid interface and leading eventually to a loss of the liquid.

[THE VITAL PULP THERAPY IN PERMANENT TEETH]

The vitality of dental pulp is essential for long-term tooth survival. The aim of vital pulp therapy is to preserve vital, healthy pulp tissue. This therapy's foundation is the elimination of bacteria from the dentin-pulp complex. The treatment option depends on the cause and extent of mineralised tooth tissue destruction. The outcome of such treatment is determined by accurate assessment of the pulp's status and the dentist's ability to predict the success of the therapy. The aim of this review is to facilitate the dentist in making a proper decision referring to vital pulp therapy in permanent teeth, and to provide an overview of new approaches in such treatment.

Local drug delivery agents as adjuncts to endodontic and periodontal therapy

In the treatment of intracanal and periodontal infections, the local application of antibiotics and other therapeutic agents in the root canal or in periodontal pockets may be a promising approach to achieve sustained/controlled drug release, high antimicrobial activity and low systemic side effects. The conventional method for the elimination of subgingival microbial infection includes mechanical debridement, irrigation with antimicrobial agents or surgical access. But, the effectiveness of conventional nonsurgical treatment is limited by lack of accessibility to bacteria in deeper periodontal pockets, and/or does not completely eliminate intracanal microorganisms. Surgical intervention may be beneficial but cannot be done in all cases, medically compromised cases and also in patients not willing to be subjected to surgical therapy. Development of local drug delivery systems provides an answer to all such difficulties. This comprehensive review tries to cover the detailed information about the latest advances in the various local drug delivery systems, their indications, contraindications and their advantages over systemic drug therapy.

Single file reciprocating technique using conventional nickel-titanium rotary endodontic files

This study was aimed to evaluate the applicability of a reciprocating movement technique with conventional nickel-titanium files for root canal preparation. Forty-four simulated canals in resin blocks were used in this study and divided as following four groups according to the instruments used and preparation methods. Group CP (n = 12) and CR (n = 12) were instrumented with continuous rotation using four files of ProFile and RaCe, respectively. Group RP (n = 10) and RR (n = 10) were instrumented with a reciprocation movement by using a single ProFile and RaCe file, respectively. The resin blocks were scanned before and after instrumentation, and the images were superimposed. To compare the efficiency of canal shaping, the preparation time, and centering ratio were calculated. Morphologic changes of tested files were examined by scanning electron microscopy (SEM). Data were analyzed by ANOVA and Duncan's post hoc test at p < 0.05. The preparation time was markedly shorter in Groups RP and RR than in Groups CP and CR. No significant difference in the centering ratio was noted between groups. Although the files used for Groups CP and CR showed no distortion under the SEM evaluation, the files used for Groups RP and RR had considerable torsional distortion. This study suggests that the reciprocating instrumentation technique using conventional nickel-titanium rotary file systems might have a comparable efficacy for the root canal shaping with reduced shaping time. Although the reciprocating technique seems to be an effective alternative to the conventional rotation technique, the risk of torsional distortion and fracture should be considered before clinical application.

Comparative antifungal efficacy of light-activated disinfection and octenidine hydrochloride with contemporary endodontic irrigants

The aim of this study was to evaluate the antifungal effects of light-activated disinfection (LAD) in comparison with contemporary root canal irrigation solutions: sodium hypochlorite and 2% chlorhexidine gluconate and a new wound antiseptic, octenidine hydrochloride. Seventy extracted teeth having single root canals were contaminated with Candida albicans for 14 days. The samples were divided into five experimental (n = 10) and two control (positive and negative) groups (n = 10): (1) LAD with toluidine blue O, (2) octenidine hydrochloride (OCT), (3) 2.5% sodium hypochlorite (2.5% NaOCl), (4) 5.25% sodium hypochlorite (5.25% NaOCl) and (5) 2% chlorhexidine. Five millilitres of each test solution was applied for 3 min, and irradiation time used for LAD was 30 s. After treatment, the dentin chips were collected from inner canal walls into vials containing phosphate buffered saline, vortexed, serially diluted, seeded on Tryptic Soy Agar plates and incubated (37 °C, 48 h). The number of colony-forming units was then counted. Differences between LAD group and positive control group were statistically significant (P < 0.05). All Candida cells were totally eliminated in root canals irrigated with OCT, 2.5% NaOCl, 5.25% NaOCl and 2% chlorhexidine groups (CFU = 0). Within the limitations of this ex vivo study, LAD had minimal antimicrobial effect on C. albicans when used 30 s, and further modifications in LAD protocol are required to improve its antifungal capability. A new wound antiseptic, octenidine hydrochloride, demonstrated better potential than LAD in elimination of Candida albicans cells and may be a promising alternative to NaOCl and chlorhexidine solutions in future.

Effects of growth factors on dental stem/progenitor cells

The primary goal of regenerative endodontics is to restore the vitality and functions of the dentin-pulp complex, as opposed to filing of the root canal with bioinert materials. A myriad of growth factors regulates multiple cellular functions including migration, proliferation, differentiation, and apoptosis of several cell types intimately involved in dentin-pulp regeneration. Recent work showing that growth factor delivery, without cell transplantation, can yield pulp-dentin-like tissues in vivo provides one of the tangible pathways for regenerative endodontics. This review synthesizes knowledge on many growth factors that are known or anticipated to be efficacious in dental pulp-dentin regeneration.

The effect of some fluids on surface oxidation and amount of released iron of stainless steel endodontic files

Endodontic files come in contact with blood, infected pulp tissue, and irrigating solutions during root canal therapy. Some instruments such as stereomicroscopy and scanning electron microscopy are used to observe corrosion of endodontic files which are complicated and dependent on preparation methods. Having knowledge of the corrosion and ion release of endodontic files can help in drawing firm deductions as to which files would perform better in the clinical scenario. Therefore, we have used energy dispersive X-ray analysis and an atomic absorption spectrophotometer to track oxygen on the surface and iron in the exposed media to observe the oxidative rate of the media. In this study, corrosion by blood was higher than other biological fluids, but less than with sodium hypochlorite (NaOCl). Observations of energy dispersive X-ray analysis and atomic absorption spectrophotometer results demonstrated that after exposure the amount of oxygen on the surface and surrounding areas increased. Therefore, the files should be rinsed as soon as possible during and after use to hinder the oxidation rate, but blood may produce a different behavior and it might be considered as a decreased risk of broken stainless steel files remaining in the root canal after treatment.

[Revascularization: a new treatment method in endodontics]

Recently a number of published articles concerning a new treatment method in traumatized young permanent teeth with a wide open apex that have lost vitality, with or without periapical lesions have shown success. This new treatment is entitled "Revascularization" and its aim is to promote root maturation in infected immature teeth with open apices. This procedure stimulates the formation of hard tissue as well as elongation and thickening of the dentinal walls and closure of the root apex. Sometimes the vitality of the teeth is regained. The aim of the present publication is to describe the revascularization technique and to clarify the indications of its use.