Ultrasound examination for the detection of simulated periapical bone lesions in bovine mandibles: an ex vivo study.

AIM: To evaluate the accuracy of ultrasound examination (USE) for the detection of artificial bone defects in bovine mandibles in the absence of complete erosion of the cortical bone plate and to determine the minimum cortical thickness that constitutes a barrier for ultrasound waves. METHODOLOGY: Sixty bovine mandibular anatomical blocks were harvested and uniformly distributed amongst six experimental groups. The negative control consisted of blocks with no intra-bony defects, whereas the positive control consisted of blocks with an artificial lesion of 2 mm diameter that perforated the buccal cortical bone plate. Two experimental groups comprised blocks with small (2 mm) and large (5 mm) artificial defects created under a cortical plate thinned to varying thicknesses. Two additional groups had small (2 mm) and large (5 mm) artificial defects that did not involve the cortical plate. After USE, the scans were saved and submitted to three blinded examiners. Sensitivity, specificity, predictive values and receiver-operating characteristics (ROC) were analysed. The significance of the findings (P < 0.05) was appraised using the chi-square statistics with the Yates correction, whilst the intra- and inter-examiner agreements were evaluated through Kappa statistics. RESULTS: USE was associated with high sensitivity (97.3%) and negative predictive value (89%), and a perfect score for specificity and positive predictive value. The ROC curve analysis revealed an accuracy of 97.8%. The k-values were 0.86 and 0.89 for the first and second examinations, respectively, demonstrating very high inter-observer agreement. The intra-observer agreement was also high (k-value = 0.92). A significant correlation between the echographic diagnosis and the presence or absence of artificial intraosseous lesions in the anatomical blocks of bovine mandibles was observed (P < 0.0001). CONCLUSIONS: USE was highly accurate and reliable for the detection of artificial lesions within bovine mandibles, regardless of the thickness or presence of the cortical plate.

Gaps at the interface between dentine and self-adhesive resin cement in post-endodontic restorations quantified in 3D by phase contrast-enhanced micro-CT.

AIM: To assess the extent of gaps between root dentine and titanium or fibreglass post restorations following cementation with a self-adhesive resin cement. METHODOLOGY: Fourteen root filled maxillary central incisors restored with prefabricated posts made of Fibreglass (n = 7) or Titanium (n = 7) and cemented with RelyX Unicem 2 were imaged by rapid, high-resolution phase contrast-enhanced micro-CT (PCE-CT) in a synchrotron X-ray imaging facility (ID19, ESRF, 34 KeV, 0.65 µm pixel resolution). Reconstructions were used to measure canal, cement and post perimeters and cross-sectional areas and interfacial gaps at 0.1 mm increments in the root canal space, along the cervical region of the tooth. Remnants of endodontic sealer (AH Plus), when present, were also quantified. Mann-Whitney and 2-way ANOVA tests were used to compare findings within slices and between the two post groups. Pearson correlation coefficients (r) were determined between the interfacial gaps and the other measured parameters. RESULTS: Clearly detectable gaps were found in 45% (±14%) of the interfaces between dentine and cement, along the canal in the cervical area of the tooth beneath the core. The length of interfacial gaps was moderately correlated to the canal cross-sectional area, to the canal perimeter and to the canal area filled by cement (R = 0.52 ~ 0.55, P < 0.001). There was no significant difference between samples with fibreglass or titanium (P > 0.01). Both post types had defect-free interfaces with cement. Endodontic sealer remnants were found on ~10% of the canal walls and were moderately correlated to the presence of gaps. Approximately 30% of the sealer-affected interfaces exhibited no detachment between dentine, sealer and cement. CONCLUSIONS: Self-adhesive cements had interfacial gaps along substantial regions of the root canal surface, which was not correlated with the amount of cement in the canal. PCE-CT proved to be an excellent non-destructive method to study root canal restorations of hydrated samples in 3D.

Impact of apical extent of root canal filling on vertical root fracture: a case-control study.

AIM: To investigate the impact of apical extent of root filling on vertical root fracture (VRF) in a case-control study. METHODOLOGY: Eighty-six patients (119 roots) diagnosed with VRF in crowned root filled anterior and posterior teeth were selected. The cases were matched individually with control teeth in a ratio of 1:1 for age (±5 years), gender, tooth type, canal instrumentation method, master apical file (MAF) size and taper, technique of canal filling and time period after root filling. All root canals had been prepared using nickel-titanium (NiTi) rotary instruments and filled using the lateral compaction technique. The apical extent of root filling (overfilled to or beyond the radiographic apex or not overfilled and short of the radiographic apex) was recorded as the dependent variable by two individual examiners. Inter-examiner agreement was obtained using Kappa statistics. Recorded numbers of overfilled and not overfilled canals in cases and controls were analysed using chi-square tests and conditional logistic regression, and odds ratio was calculated. In addition, the frequency distribution of vertical and cross-sectional extensions and the course of VRFs were evaluated. RESULTS: The mean age of patients with VRFs was 50 ± 10 years with 27 (31%) males and 59 (69%) females. The Kappa score for inter-observer agreement was 0.832 (P < 0.001). There was a significant difference between cases and controls with respect to apical extent of root filling (P < 0.0001). When compared to roots not overfilled, overfilled roots had 11.5 times higher odds for occurrence of VRF (OR = 11.5; CI: 4.99 - 26.48). Most VRFs had a complete corono-apical longitudinal extension and were present bucco-lingually/palatally. CONCLUSION: After matching for age, gender, tooth type, MAF size and taper, canal filling technique and time period after root filling, root canals filled to or beyond the radiographic apex following lateral compaction had a greater association with VRF than canals filled short of the radiographic apex.

[The content of publications in the Netherlands Journal of Dentistry - an analysis of patterns over time]. / De inhoud van publicaties in het Nederland Tijdschrift voor Tandheelkunde. Een patroonanalyse over de tijd.

In 2018, the Netherlands Journal of Dentistry (NTVT) had been published for 125 years: reason for a systematic look at the subjects that have received attention since 2000. These subjects were subsequently compared to those in Dutch dental publications in international literature and to leading fields in oral health care. The analysis revealed an increase in the attention given to certain fields in the Netherlands Journal of Dentistry, such as public dental health, during the past 18 years and a decrease in the attention given to other subjects, such as basic scientific research. In addition, there was a limited correlation between fields involving the greatest cost of care, such as cariology and preventive dentistry, and research activity. This held true both for international publications and publications in the Netherlands Journal of Dentistry.

European Society of Endodontology position statement: External Cervical Resorption.

This Position Statement represents the consensus of an expert committee convened by the European Society of Endodontology (ESE) on External Cervical Resorption (ECR). The statement is based on current clinical and scientific evidence as well as the expertise of the committee. The primary aim is to provide a current authoritative position on the aetiology, histopathology, clinical presentation and management of ECR, and also to highlight areas where there is minimal evidence. Previously published review articles provide more detailed background information and the basis for this position statement (International Endodontic Journal 51, 1205, 2018, International Endodontic Journal 51, 1224, 2018). It is intended that this position statement will be updated at appropriate intervals, as further evidence emerges.

[External cervical root resorption]. / Externe cervicale wortelresorptie.

External cervical root resorption begins at the root surface as result of odontoclastic activity in the cervical area and is progressive in character. The pulp is only affected at a later stage of the process. The aetiology and pathogenesis of external cervical root resorption is not fully understood. Possible predisposing factors are, among others, orthodontic treatment, trauma, internal bleaching, damaged cemento-enamel junction, bruxism and hypoxia. A 'pink spot' often is the first clinical sign and a two-dimensional radiograph usually presents an amorphous radiolucency with undefined borders. Cone-beam computed tomography is an emerging technique aiding the diagnosis of and prognosis and treatment plans for external root resorption. An external or internal treatment approach can be chosen, depending on the size of the defect.

Full text publication rates of research abstracts presented at the European Society of Endodontology (ESE) Congresses in the last 20 years.

AIM: To evaluate the full-text publication rates of scientific research abstracts presented at the European Society of Endodontology (ESE) Congresses held between 1993 and 2013 (a total of 11 occasions) and to determine factors associated with the manuscripts. METHODOLOGY: An electronic database search was conducted from January 2015 to December 2016 to identify full text English written publications of the research abstracts presented at the last 11 ESE Biennial Congresses from 1993 to 2013. For each occasion, research abstract information were retrieved from the International Endodontic Journal (IEJ) through the official website of the ESE and the following parameters for each abstract presentation were recorded: Year of presentation, first author's affiliation, geographic origin, and type of study. Following full-text article identification, additional information was recorded such as: Year and journal of publication, elapsed time until full publication and number of authors per presentation and publication. RESULTS: A total of 1165 research abstracts were presented, of which 401 (34.4%) were finally published as full-length articles. Overall 235 articles (58.6%) were published either in the International Endodontic Journal (IEJ, 35.7%) or Journal of Endodontics (JOE, 22.9%). The mean time between abstract presentation and full-text publication was 18.95 months. Munich (2001) had the highest publication rate (44%) whereas Lisbon (2013) had the highest number of published articles (77). Turkey was the country with the highest number of published abstracts (56). However, the Netherlands was the country with the highest number of publications related to the number of presentations (21/26) (80.7%). Differences in authorship between presentation and full publication were found in 179 (44.6%) articles. CONCLUSIONS: A substantial number of research abstracts presented at ESE congresses were not published in peer reviewed journals. Authors prefer to publish their research papers in international journals with high impact factor. This article is protected by copyright. All rights reserved.

[A Phd completed 4. Interactions between root canal irrigants, sealers and dentin]. / Hora est 4. Interacties tussen irrigatie-oplossingen, wortelkanaalcementen en dentine.

In the field of endodontology, antibacterial activity of irrigants has been investigated many times. The influence of these solutions on the bonding of root canal sealers, however, has hardly been studied. The objective of this doctoral research was to determine the interactions between root canal sealers and root dentin, and to determine the influence of irrigants on these interactions. The various studies revealed that irrigants have an influence on the bonding of sealers based on epoxy resin, calcium hydroxide, silicones and calcium silicate. In the case of a sealer based on epoxy resin (AH Plus), the irrigation protocol had an influence on the bond strength (adhesion) on dentin, by means of which the seal was also improved. The results of this research produced better insights into the mechanisms at play in the adhesive properties of root canal sealers. Eventually, this might result in improved treatment outcomes of root canal treatments.

[Endodontics in motion: new concepts, materials and techniques 5. The dynamics of the periapical laesion]. / Endodontologie in beweging: nieuwe concepten, materialen en technieken 5. De dynamiek van de periapicale laesie.

Periapical laesions are a frequently occurring phenomenon, in both untreated teeth and teeth which have undergone endodontic treatment. Various factors have been found to positively influence the effectiveness of endodontic treatment, which is defined by a lack of clinical symptoms and also the absence or shrinkage of the periapical laesion. The chance of a painful exacerbation of a persistent periapical laesion is small, even if the area of the laesion has expanded, which happens in approximately 50% of the cases. The survival of endodontically treated teeth with a periapical laesion is 87% after 10 years. Restorative reasons frequently are the main reason for extraction and the presence of a periapical laesion is seldom the reason for losing a tooth. The influence of the periapical laesion on general health is still unclear.

[Persistent dento-alveolar pain disorder (PDAP)]. / Persisterende dentoalveolaire pijn (PDAP).

Dento-alveolar pain is common in the orofacial area. Persistent dento-alveolar pain could be experienced without an identifiable etiology with poor response to existing treatments. Confusion about the diagnosis and classification of persistent dento-alveolar pain (PDAP) disorders could explain the difficulties in treatment and unfavorable prognosis. Recently, initial steps were made to improve the taxonomy and diagnostic criteria for PDAP in order to improve clinical research and care.

The correlation between fluid transport and push-out strength in root canals filled with a methacrylate-based filling material.

AIM: To investigate the correlation between fluid transport and dislocation resistance in canals filled with a methacrylate-based filling material. METHODOLOGY: The root canals in sixty-five single-rooted human teeth were prepared to size 40, 0.06 taper. Sixty roots were filled with a single-cone technique using RealSeal SE sealer and divided into 3 groups, whilst five roots served as fluid transport positive control. Group 1 (n = 20): correlation group. Specimens were consecutively tested with fluid transport for 90 min and thereafter with the push-out test at coronal and apical root levels. Group 2 (n = 20): push-out control. Specimens were only subjected to the push-out test at coronal and apical root levels. Group 3 (n = 20): fluid transport negative control. Specimens were totally covered with nail varnish. The correlation between fluid transport and dislocation resistance was assessed by Kendall's tau-b coefficient. The Mann-Whitney U-test was used to compare dislocation resistance between groups 1 and 2 and fluid transport between groups 1 and 3. Significance level was set at P < 0.05. RESULTS: Kendall's tau-b correlation coefficients between fluid transport and dislocation resistance were weak, being coronally 0.139 (P = 0.444) and apically -0.080 (P = 0.658). No significant difference in dislocation resistance could be detected between groups 1 and 2 at both root levels (P = 0.052 and P = 0.336, respectively). CONCLUSION: No significant correlation could be identified between fluid transport and dislocation resistance, meaning that the corono-apical sealing ability of a methacrylate-based root canal filling is independent of its adhesive properties as indicated by its dislocation resistance.

Cone beam computed tomography in Endodontics - a review.

Cone beam computed tomography (CBCT) produces undistorted three-dimensional information of the maxillofacial skeleton, including the teeth and their surrounding tissues with a lower effective radiation dose than computed tomography. The aim of this paper is to: (i) review the current literature on the applications and limitations of CBCT; (ii) make recommendations for the use of CBCT in Endodontics; (iii) highlight areas of further research of CBCT in Endodontics.

European Society of Endodontology position statement: the use of CBCT in endodontics.

This Position Statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on the use of Cone Beam Computed Tomography (CBCT). The statement is based on the current scientific evidence, and provides the clinician with evidence-based criteria on when to use CBCT in Endodontics. Given the dynamic and changing nature of research, development of new devices and clinical practice relating to CBCT, this Position Statement will be updated within 3 years, or before that time should new evidence become available.

Detection and measurement of artificial periapical lesions by cone-beam computed tomography.

AIM: To test the ability of periapical radiography (PA) and cone-beam computed tomography (CBCT) to determine the presence/absence of periapical lesions and examine the reliability of volumetric measurements of periapical lesions on CBCT scans. METHODOLOGY: After tooth extractions in human mandibles, bone defects were cut at the base of extraction sockets to mimic periapical bone lesions. The teeth were then returned into the extraction sockets. Sixty-three roots of anterior teeth, premolars and molars with artificial periapical lesions and 37 roots without lesions were examined with PA and CBCT. Presence/absence of periapical lesion was noted. The CBCT-based volume of each lesion (Vct) was measured using Amira software 5.4 (Visage Imaging GmbH, Berlin, Germany). A replica of each lesion was created using silicone impression material, and the volume of the replica was measured using a water displacement method, representing the physical volume of the lesion (Vp). Regression analysis was used to test the correlation between the Vp and Vct values. RESULTS: The positive and negative predictive values and accuracy for CBCT in diagnosing periapical lesions were all 1, compared with 1, 0.64 and 0.79 for PA diagnosis. Twenty-one (33%) lesions were undetected by PA. The Vp (21.5 ± 11.0 mm(3) ) and Vct (21.4 ± 11.5 mm(3) ) values of 63 lesions were highly correlated (R(2) = 96.9%, P < 0.001). CONCLUSION: Cone-beam computed tomography is more accurate than PA in diagnosing periapical lesions associated with mandibular teeth. The volumes of artificial mandibular periapical lesions were accurately measured with CBCT data.

Bisphosphonates and their clinical implications in endodontic therapy.

This review gives an overview of the factors that may play a role in the development of osteonecrosis of the jaw in patients treated with bisphosphonates (BPs) and undergoing nonsurgical endodontic treatment as well as some recommendations for its prevention. BPs are a widely prescribed group of drugs for diverse bone diseases. The occasional but devastating adverse effect of these drugs has been described as bisphosphonate-related osteonecrosis of the jaw (BRONJ). As this condition is debilitating and difficult to treat, all efforts should be made to prevent its occurence in patients at risk. The main triggering event is considered to be dental extraction. Even though nonsurgical endodontic treatment appears to be a relatively safe procedure, care remains essential. After an overview of this class of drugs, the clinical presentation, epidemiology and pathogenesis of BRONJ, as well as the possible risk factors associated with its development after nonsurgical endodontic treatment will be described. Finally, several strategies will be proposed for the prevention of BRONJ during nonsurgical endodontic treatment.

Branching the risks: architectural plasticity and bet-hedging in Mediterranean annuals.

It has been suggested that architectural plasticity in shoot size and number allows plants to manage environmental risks. Simpler structures require shorter development times and fewer resources, which secure minimal fitness even under risky and unfavourable conditions. Here we tested the hypothesis that the magnitude of such architectural plasticity depends on the species' developmental strategy. Specifically, species with late reproduction were expected to express the highest levels of architectural plasticity in response to environmental cues predicting high probability of abrupt deterioration in growth conditions. This hypothesis was tested by comparing Mediterranean and semi-arid populations of three species, which differed in growth strategy: Trifolium purpureum, a determinate and late flowerer, and Emex spinosa and Hippocrepis unisiliquosa that flower indeterminately throughout the season. All plants were exposed to varying levels of water availability and competition, but only T. purpureum displayed plastic architectural responsiveness to the experimental manipulations. In contrast, the early and extended step-by-step flowering of both E. spinosa and H. unisiliquosa reflected a relatively deterministic bet-hedging reproductive schedule, whereby minimum fitness is secured even under adverse conditions. These two opposing strategies gave contrasting results, with E. spinosa and H. unisiliquosa displaying reduced efficiency under favourable conditions under which T. purpureum had the highest reproductive efficiency. The evolutionary interplay between deterministic risk-averse and plastic risk-prone growth strategies might reflect contrasts in the probability and severity of environmental risks, and the costs of missed opportunities.

[Persistent pain following endodontic treatment]. / Persisterende pijn na endodontische behandeling.

Dental pain is a very common pain in the orofacial area. Patients sometimes experience persistent pain following endodontic treatment. The cause of this pain can be found in the endodontically treated tooth itself when the pain persists after an inadequately performed treatment. Persistent pain is also possible after an apparently adequate endodontic treatment. Moreover the pain can have an odontogenic origin, in cases where the diagnostic procedure may have failed. A non-odontogenic cause can be located in proximate or more remote structures, which may be a question of systemic diseases or pain from neuropathic, neurovascular and/or psychogenic conditions. A thorough clinical examination forms the basis for the establishment of a valid diagnosis.

The ability of cone-beam computed tomography to detect simulated buccal and lingual recesses in root canals.

AIM: To compare the ability of cone-beam computed tomography (CBCT) and digital periapical radiographs (PR) to detect simulated tissue-occupied recesses in root canals. METHODOLOGY: A standard canal was created in 30 extracted mandibular premolar roots. Each root was longitudinally split into buccal and lingual halves. In 20 teeth, a standard groove, 4mm in length, 0.5mm deep and 0.3mm wide, was prepared on each root half and filled with radiolucent plasticine (a modelling clay), simulating tissue-occupied buccal and lingual recesses. In the other 10 teeth, no grooves were cut. Each root was reassembled and filled with laterally compacted gutta-percha and sealer. PR and CBCT were used to detect the plasticine-filled grooves. The images were pooled and blindly evaluated by three calibrated examiners (A, B and C). A chi-square test was used to analyse the data. RESULTS: Examiner A, B, C detected grooves on CBCT scans in 20, 20 and 23 teeth, respectively, of which 19, 18 and 19 were true positives. The accuracy of CBCT in diagnosing plasticine-filled grooves was 82-92% for three examiners, significantly higher than the accuracy of PR (30-33%; P<0.001). CONCLUSIONS: Cone-beam computed tomography accurately detected simulated tissue-occupied buccal and lingual recesses.