In vivo schistosomicidal activity of (±)-licarin A-loaded poly(ε-caprolactone) nanoparticles.

Schistosomiasis mansoni is an infectious parasitic disease caused by worms of the genus Schistosoma, and praziquantel (PZQ) is the medication available for the treatment of schistosomiasis. However, the existence of resistant strains reinforces the need to develop new schistosomicidal drugs safely and effectively. Thus, the (±)-licarin A neolignan incorporated into poly-Ɛ-caprolactone (PCL) nanoparticles and not incorporated were evaluated for their in vivo schistosomicidal activity. The (±)-licarin A -loaded poly(ε-caprolactone) nanoparticles and the pure (±)-licarin A showed a reduction in the number of worm eggs present in spleens of mice infected with Schistosoma mansoni. In addition, the (±)-licarin A incorporated in the concentration of 20 mg/kg and 200 mg/kg reduced the number of worms, presenting percentages of 56.3% and 41.7%, respectively.

A rapid chair-side method for the estimation of oral bacterial colonization density.

AIMS: Caries and periodontal disease are associated with inadequate control of oral bacteria. Since conventional microbiological evaluations are impractical in dental clinics or public engagement activities, a rapid test for the quantification of oral bacteria represents a useful tool. We describe the development of a colour change test to rapidly estimate bacterial colonisation density in the mouth. METHODS AND RESULTS: Volunteers rinsed with milk or milkshake. Viability indicators were added and colour changes quantified during incubation. Using milkshake and the resazurin-based solution PrestoBlue (9% v/v), the method distinguished between samples before and after brushing within 5 min. Colour changes were quantified and viable counts were obtained using oral rinses. Measured colour changes strongly correlated with total counts of both anaerobes and streptococci (Spearman's correlation coefficient of 0·782 and 0·769, respectively, P ≤ 0·001) and with perceived changes, as determined by volunteers (n = 10) visually ranking images. CONCLUSIONS: The resazurin milkshake test can rapidly and visually quantify viable bacteria in oral samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The resazurin milkshake test could serve as a sensitive semi-quantitative method for measuring oral bacteria in human oral rinse samples.

"Armed to the teeth": The multiple ways to survive insecticidal and predatory challenges in Aedes aegypti larvae.

Environmental pollutants, such as insecticides, can alter the equilibrium of aquatic ecosystems, particularly those closely located to human occupations. The use of such anthropogenic compounds frequently results in the selection of resistant individuals. However, how the underlying insecticide resistance mechanisms interplay with the abilities of the resistant individuals to cope with other environmental challenges (e.g., predators) has not received adequate attention. Here, we evaluated whether resistance to pyrethroid insecticides in larvae of the yellow fever mosquito, Aedes aegypti (Diptera: Culicidae), would affect their abilities to survive other environmental challenges. We assessed the susceptibilities of the pyrethroid-resistant larvae to other insecticides (i.e., the oxadiazine indoxacarb and juvenile hormone mimic pyriproxyfen) and determined the activities of potential detoxification enzymes. Finally, we also recorded potential alterations in larva swimming behavior in the presence of predators, such as the water bug Belostoma anurum (Hemiptera: Belostomatidae). Our results revealed that high pyrethroid resistance was associated with moderate resistance to the other two insecticides. Furthermore, this multiple resistance was associated with higher detoxification activity by glutathione-S-transferases and general esterases. Interestingly, in comparison with insecticide-susceptible larvae, the pyrethroid-resistant larvae not only swam for longer periods and distances, but also took longer to be captured by B. anurum nymphs. Collectively, our findings revealed increased abilities to survive natural environmental challenges (e.g., predatory attacks) in mosquito larvae that express physiological and behavioral changes associated with multiple resistance to insecticides.

Histological evaluation of the repair process of replanted rat teeth after storage in resveratrol dissolved in dimethyl sulphoxide.

BACKGROUND/AIM: The storage media is directly related to the prognosis of avulsed teeth, with resveratrol drawing attention due to its antioxidant and anti-inflammatory proprieties. The aim of this study was to evaluate the repair process in rat teeth following delayed replantation after storage in resveratrol (R) dissolved in dimethyl sulphoxide (DMSO). MATERIALS AND METHODS: The upper right central incisors of 36 rats were divided into 4 groups. In group I, the teeth were extracted and immediately replanted. Group II teeth were stored in 50 mL R+DMSO (0.0512 g/mL), whereas group III teeth were stored in 50 mL pure DMSO, both for a period of 60 minutes. The teeth of group IV were stored dry for 60 minutes. The teeth of groups II, III and IV were then replanted, and the animals were euthanized after 60 days. Longitudinal histological cuts were HE stained for histomorphometric analysis of the periodontal ligament, alveolar bone, cementum and dentin. RESULTS: The analysis of HE stained histological sections showed the following statistical differences: the acute inflammatory process in the epithelial insertion was less prominent in group II than in group III; the organization of the periodontal ligament was better in group I, while the intensity and extension of acute inflammation in the periodontal ligament were better in group I, and worse in group III; the chronic inflammatory infiltrate was less in groups I and IV, and the depth and extent of resorption, as well as the repair of root resorption, were better in group I. CONCLUSIONS: Storage in R+DMSO solution did not inhibit root resorption after delayed replantation in rat teeth. It is concluded that pure DMSO is not a suitable transport medium for avulsed teeth.

Tooth injuries: Knowledge of parents of public school students from the city of Alfenas, Minas Gerais, Brazil.

BACKGROUND/AIMS: The prognosis of traumatized teeth can be optimized if appropriate procedures are following at the time of the accident. The aim of this study was to evaluate the level of knowledge of students' parents from a group of Brazilian schools regarding fracture and tooth avulsion in permanent teeth. METHODS: Parents of 802 students were interviewed using a pre-tested questionnaire designed to explore how they would manage their child's dental avulsion or fracture. RESULTS: Among the parents, 8.6% reported their child had already suffered tooth injuries. Concerning dental fracture, 49.5% considered the possibility of bonding the tooth fragment and, for dental avulsion, 65.5% considered tooth replantation. Approximately 33.5% of parents would take the child to the dental office in case of fracture or dental avulsion, and of those, 66.2% would do so immediately. Further, 69.5% (for fracture) and 70.4% (for avulsion) would do so regardless of symptoms; only 24.2% and 21.3%, respectively, would seek care only if there was pain. In case of avulsion, 22.3% of those interviewed would store the tooth in liquid, such as saline solution (17.8%), water (16.4%) and fresh milk (12.2%). CONCLUSION: Parents had partial and insufficient knowledge as to the proper approach to be adopted in cases of fracture and dental avulsion. Previous experience of dental trauma was not related to more appropriate behavior regarding these injuries.

Tooth fragment reattachment techniques-A systematic review.

BACKGROUND/AIM: Several strategies have been developed for tooth fragment reattachment following fracture. Although many techniques have been reported, there is no consensus on which one has the best results in terms of the bond strength between the fragment and the dentin over time. The aim of this study was to assess the currently reported tooth fragment reattachment techniques for fractured crowns of anterior teeth. MATERIALS AND METHODS: The PubMed, LILACS, Web of Science, Cochrane, and Scopus databases were searched in October 2016, and the search was updated in February 2017. A search of the gray literature was performed in Google Scholar and OpenGrey. Reference lists of eligible studies were cross-checked to identify additional studies; gray literature and ongoing trials were investigated. Two authors assessed studies to determine inclusion and undertook data extraction. Case reports/series of three or more cases, cross-sectional studies, cohort studies, and in vivo clinical trials in all languages were included. RESULTS: Five articles remained after screening. These studies predominantly reported on fragment reattachment with composite resin and resin cement. There was little consistency among the studies in regard to the technique used for tooth fragment reattachment and length of the follow-up period. CONCLUSIONS: According to the evidence found in the studies included in this review, simple tooth fragment reattachment was the preferred reattachment technique. An increase in the bond strength between tooth fragment and dentin was observed when an intermediate material was used. Further investigation is needed, using standard follow-up periods and larger samples.

In vivo and in silico anti-inflammatory mechanism of action of the semisynthetic (-)-cubebin derivatives (-)-hinokinin and (-)-O-benzylcubebin.

(-)-Cubebin (CUB), isolated from seeds of Piper cubeba, was used as starting material to obtain the derivatives (-)-hinokinin (HK) and (-)-O-benzyl cubebin (OBZ). Using paw edema as the experimental model and different chemical mediators (prostaglandin and dextran), it was observed that both derivatives were active in comparison with both negative (5% Tween® 80 in saline) and positive (indomethacin) controls. The highest reduction in the prostaglandin-induced edema was achieved by OBZ (66.0%), while HK caused a 59.2% reduction. Nonetheless, the dextran-induced paw edema was not significantly reduced by either of the derivatives (HK or OBZ), which inhibited edema formation by 18.3% and 3.5%, respectively, in contrast with the positive control, cyproheptadine, which reduced the edema by 56.0%. The docking analysis showed that OBZ presented the most stable ligand-receptor (COX-2 - cyclooxygenase-2) interaction in comparison with CUB and HK.

Histomorphometric analysis of the healing process after the replantation of rat teeth maintained in bovine milk whey and whole milk.

BACKGROUND/AIM: In cases of tooth avulsion, a minimal extra-alveolar dry storage period or the use of a suitable storage medium is crucial to maintaining the vitality of the periodontal ligament. Whey has similar properties to milk and has therefore been investigated as a storage medium for avulsed teeth. The aim of this study was to evaluate the repair process after replantation of rat teeth kept in whey and whole milk. MATERIALS AND METHODS: Thirty-six male rats were divided into four groups of nine animals. The upper right incisor was extracted under general anesthesia. In Group I, the teeth were immediately replanted without treatment (positive control). In Group II, the teeth were stored in 50 mL of sweet whey. In Group III, the teeth were kept in 50 mL of long-shelf-life whole milk (UHT, Parmalat® ). In Group IV, the teeth were kept dry (negative control). After 60 minutes, the teeth in Groups II, III, and IV were replanted into their sockets. The animals were subjected to euthanasia 60 days after replantation. The specimens were stained with hematoxylin and eosin for histomorphometric analysis. RESULTS: The organization of the periodontal ligament in Group II (whey) was similar to that in Groups I (immediate replantation) and III (whole milk) (P > .05). However, some specimens in this group exhibited periodontal fibers inserted into the bone and cementum throughout the entire length of the periodontal ligament. This occurred in the group submitted to immediate replantation, whereas this histological aspect was not seen in whole milk group. Group IV (late replantation) had a higher rate of root resorption. Regarding the root repair process, it was expected that Group I (immediate) would demonstrate more favorable repair than the other groups. However, Group III (whole milk) had better results when compared to Groups II (whey) and IV (late) (P < .05). CONCLUSION: Whey and whole milk achieved similar results and were adequate storage media for avulsed teeth.

In vitro schistosomicidal activity of the lignan (-)-6,6'-dinitrohinokinin (DNHK) loaded into poly(lactic-co-glycolic acid) nanoparticles against Schistosoma mansoni.

CONTEXT: (-)-6,6'-Dinitrohinokinin (DNHK) display remarkable antiparasitic activity and was, therefore, incorporated into a nanoparticle formulation. OBJECTIVE: Incorporation of DNHK in poly lactic-co-glycolic acid (PLGA) nanoparticles aiming to improve its biological activities. MATERIALS AND METHODS: Synthesis, characterization and incorporation of DNHK into glycolic acid (PLGA) nanoparticles by nanoprecipitation method. The nanoparticles were characterized by ultraviolet-visible spectroscopy, X-ray diffraction, field emission electron microscopic scanning mansoni (FESEM), and dynamic light scattering (DLS). For the in vitro test with Schistosoma mansoni, the DNHK-loaded PLGA was diluted into the medium, and added at concentrations 10-200 µM to the culture medium containing one adult worm pair. The parasites were kept for 120 h and monitored every 24 h to evaluate their general condition, including: pairing, alterations in motor activity and mortality. RESULTS: The loaded PLGA nanoparticles gave an encapsulation efficiency of 42.2% and showed spherical characteristics in monodisperse polymeric matrix. The adult worm pairs were separated after 120 h of incubation for concentrations higher than 50 µM of DNHK-loaded PLGA. The groups incubated with 150 and 200 µM of DNHK-loaded PLGA for 24 and 120 h killed 100% of adult worms, afforded LC50 values of 137.0 ± 2.12 µM and 79.01 ± 1.90 µM, respectively, which was similar to the effect displayed by 10 µM of praziquantel. DISCUSSION AND CONCLUSIONS: The incorporation of DNHK-loaded showed schistosomicidal activity and allowed its sustained release. The loaded PLGA system can be administered intravenously, as well as it may be internalized by endocytosis by the target organisms.

Treatment of Extrusive Luxation in Permanent Teeth: Literature Review with Systematic Criteria.

INTRODUCTION: Extrusive luxation is a traumatic dental injury caused by the action of oblique forces, characterized by partial displacement of the tooth out of its socket. The ideal treatment for this type of trauma involves repositioning the tooth in its socket. However, in cases where the tooth cannot be repositioned, different options may be considered, such as intentional reattachment and orthodontic intrusion. The aim is to review the literature on the extrusive luxation of permanent teeth while assessing the risks of complications for two methods of delayed treatment for extrusive luxation. MATERIALS AND METHODS: An electronic search from August 2005 to August 2014 was performed by two reviewers independently, and conflicts were resolved by a third reviewer. The databases used were PubMed and Scopus; the reviewers performed a manual search of the following journals: Dental Traumatology, American Journal of Orthodontics, and Clinical Oral Investigation. RESULTS: After removing the duplicate studies, 328 articles were found. Out of these, 321 were rejected as not addressing the proposed research topic. In addition, five articles were excluded because apical repositioning was used for treatment. Therefore, four articles formed the basis of the study. CONCLUSION: Factors, such as root formation, the degree of tooth mobility, and the presence of tooth vitality were decisive for the choice of treatment. However, both treatments were effective and showed favorable results, i.e., without periodontal and root damage. CLINICAL SIGNIFICANCE: Knowledge of the risks of complications among two methods of delayed treatment for extrusive luxation, as well as other important factors to take into consideration when choosing a treatment assists dentists in improving the prognostic.

Foraging with finesse: A hard-fruit-eating primate selects the weakest areas as bite sites.

OBJECTIVES: Fruit husks are rarely uniformly hard, varying in penetrability via sulci and changes in thickness. We tested whether a hard-food specialist primate i) bites randomly on food fruit husk surfaces to access seeds, or ii) selects areas most easily penetrated by canines. We consider this would occur so as to minimize deployed mechanical force, energetic expenditure and risk of dental breakage when feeding. METHODS: A sulcus is the natural line of weakness where a dehiscent fruit breaks open. Using fruits dentally opened for seeds by golden-back uacaris (Cacajao ouakary) we: 1) analysed bite mark distribution on surface of four fruits types (hard-with-sulcus, soft-with-sulcus, hard-no-sulcus, soft-no-sulcus); 2) quantified the force needed to penetrate hard and soft fruits at sulci and elsewhere on fruit surface; 3) measured fruit wall thickness and correlated it with bite-mark distribution in all four categories of fruit. RESULTS: 1) Bite marks were distributed at random only on surfaces of soft fruits. For other fruits types, bite locations were concentrated at the thinnest areas of husk, either over the entire surface (non-sulcate fruits), or at sulci (sulcate fruits). 2) For hard-husked fruits, areas where uacaris concentrated their bites were significantly easier to penetrate than those where they did not. CONCLUSIONS: This hard-fruit feeding specialist primate is not biting at random on the surface of diet fruits. To access seeds they are focusing on those areas requiring less force to penetrate. This may be to save energy, to minimize the risk of breaking teeth used in food processing, or a combination of both. The study shows, for the first time, the subtlety by which these powerfully-jawed animals process their diet items.

Antimicrobial activity of apitoxin, melittin and phospholipase A2 of honey bee (Apis mellifera) venom against oral pathogens.

In this work, we used the Minimum Inhibitory Concentration (MIC) technique to evaluate the antibacterial potential of the apitoxin produced by Apis mellifera bees against the causative agents of tooth decay. Apitoxin was assayed in natura and in the commercially available form. The antibacterial actions of the main components of this apitoxin, phospholipase A2, and melittin were also assessed, alone and in combination. The following bacteria were tested: Streptococcus salivarius, S. sobrinus, S. mutans, S. mitis, S. sanguinis, Lactobacillus casei, and Enterococcus faecalis. The MIC results obtained for the commercially available apitoxin and for the apitoxin in natura were close and lay between 20 and 40 µg / mL, which indicated good antibacterial activity. Melittin was the most active component in apitoxin; it displayed very promising MIC values, from 4 to 40 µg / mL. Phospholipase A2 presented MIC values higher than 400 µg / mL. Association of mellitin with phospholipase A2 yielded MIC values ranging between 6 and 80 µg / mL. Considering that tooth decay affects people's health, apitoxin and its component melittin have potential application against oral pathogens.

Validation of the Basic Erosive Wear Examination.

The Basic Erosive Wear Examination (BEWE) is a practical index for screening tooth wear, using a 4-point ordinal scale (0-3). The highest score is recorded in each sextant and a total score (or BEWE sextant cumulative) is calculated per subject. This study aims to investigate if the BEWE sextant cumulative score compares to one comprising a percentage score from all tooth surfaces and as a highest BEWE per subject. The aim is to assess the validity of this score. A total of 350 subjects were recruited from hospital and general practice in south-east England. Buccal, occlusal and lingual/palatal BEWE scores were collected and percentages calculated based on scores 1, 1 and above, 2 and above and 3. BEWE sextant cumulative scores and highest BEWE scores were also recorded per subject. Spearman's correlation coefficients (p values) assessed the relationship between BEWE sextant cumulative scores, BEWE percentages and BEWE highest score per subject. The BEWE sextant cumulative score correlates significantly to a BEWE score taken as a percentage score from all tooth surfaces (Spearman's r > 0.5, p < 0.001) and especially to BEWE surface scores of 1 and above and 2 and above (r > 0.8, p < 0.001) and as a highest surface score per subject (r > 0.8, p < 0.001). BEWE sextant score provides a representation of tooth wear on all tooth surfaces. This study validates a tooth wear index, which provides clinicians with risk indicators of a patient's level of tooth wear and may help to guide clinical management.

A novel method to quantify dentine tubule occlusion applied to in situ model samples.

OBJECTIVES: To develop an innovative computerised routine, in conjunction with a minimally destructive imaging technique, to quantify dentine tubule occlusion. METHODS: Polished human dentine samples (n = 480) were brushed during a 4-day in situ study with two occlusion-based dentifrices, a sodium fluoride control dentifrice (1,450 ppm) or water. Samples were imaged with tandem scanning microscopy (TSM) and conventional scanning electron microscopy (SEM). The level of dentine patency was then assessed using a visual ordinal scale ('standard') or quantitatively using a specially designed computational routine. RESULTS: The occlusion-based dentifrice resulted in significantly less patent dentine than controls for the 'standard' (p = 0.01) assessment, but not for computer analyses (p = 0.10). The correlation of the number of individual patent tubules counted visually and by the computational routine in calibrations and in the in situ study was ≥ 0.8. CONCLUSIONS: This study identified a new computer-based routine, capable of objectively quantifying the patency of dentine imaged by SEM and TSM.

A comparison of cone beam computed tomography and periapical radiography for the detection of vertical root fractures in nonendodontically treated teeth.

AIMS: To compare in an ex vivo model, the diagnostic accuracy of periapical radiography and cone beam computed tomography (CBCT) for the detection of artificially induced incomplete and complete vertical root fractures (VRFs), and to determine whether the width of the VRFs had an impact on the diagnostic accuracy of the imaging systems. METHODOLOGY: Incomplete VRFs were induced in 30 nonendodontically treated human mandibular premolar and molar teeth. VRF widths were measured using optical coherence tomography. Complete VRFs were induced in 15 of these teeth. 3D Accuitomo and i-CAT CBCT scans and periapical radiographs were taken prior to and after fracture induction. Receiver operating characteristic (ROC) analysis was carried for each imaging technique. In addition, values for sensitivity, specificity, positive and negative predictive values, inter- and intra-examiner agreement were calculated. RESULTS: In the ROC analysis, both CBCT scanners were significantly more accurate than periapical radiography for the detection of incomplete VRFs (P < 0.05). The overall area under the ROC curve (AUC) values for 3D Accuitomo, i-CAT and periapical radiography were 0.687, 0.659 and 0.540, respectively. The sensitivity of 3D Accuitomo, i-CAT and periapical radiography was 27%, 28% and 3% respectively. Interexaminer agreement for the detection of incomplete fractures with periapical radiographs, 3D Accuitomo and i-CAT was 0.020, 0.229 and 0.333, respectively. Both CBCT scanners were significantly more accurate (P < 0.01) in detecting VRFs of ≥50 µm compared with VRFs of <50 µm. 3D Accuitomo was significantly better than i-CAT in detecting VRFs of <50 µm (P < 0.05). For complete fractures, the AUC values for 3D Accuitomo (0.999) and i-CAT (0.998) were significantly higher (P < 0.05) than for periapical radiography (0.724). CONCLUSIONS: Under the conditions of this ex vivo study, periapical radiographs and CBCT were unreliable for the detection of simulated incomplete VRFs. The widths of the fractures appeared to have an impact on the diagnostic accuracy of CBCT as the detection of VRFs of ≥50 µm was significantly higher than those of <50 µm. The detection of complete fractures was significantly higher for all systems than that of incomplete fractures.

Reconstruction of the edentulous mandible with fresh frozen bone grafts and implants: a 4-year report of a prospective clinical study.

Allogen bones from tissue bank are often used in dentistry although the data analyzing the long-term success in mandible are scarce. This study evaluated by computed tomography scans (CTS) the bone resorption around the implants installed on fresh frozen bone (FFB) previously grafted, after 4 years of occlusal rehabilitation. Six subjects were grafted with blocks in posterior mandible using FFB. After 6 months, 27 implants were placed and after further 4 months the prostheses were delivered. Following 4 years of the final rehabilitation procedures, another CTS was done in order to measure the resorption in periimplant bone crest at the proximal implant surfaces. It was observed a 100 % survival rate of the implants after 4 years of the fixture installation. The marginal bone resorption after 48 months was 2.82 ± 1.63 mm and no statistical significant difference was observed along the region where the implants were fixed when compared with the interimplantar space. In addition there was no significant correlation regarding the length of the implant used and the amount of marginal bone resorption. The conclusion is that grafted areas with FFB are suitable to implant installation in the posterior mandible.

Sex-specific trade-offs and compensatory mechanisms: bite force and sprint speed pose conflicting demands on the design of geckos (Hemidactylus frenatus).

One of the more intuitive viability costs that can result from the possession of exaggerated sexually selected traits is increased predation pressure as a result of reduced locomotor capacity. Despite mixed empirical support for such locomotor costs, recent studies suggest that such costs may be masked by compensatory traits that effectively offset any detrimental effects. In this study, we provide a comprehensive assessment of the locomotor costs associated with improved male-male competitive ability by simultaneously testing for locomotor trade-offs and potential compensatory mechanisms in territorial male and non-territorial female geckos. Fighting capacity and escape performance of male Asian house geckos (Hemidactylus frenatus) are likely to pose conflicting demands on the optimum phenotype for each task. Highly territorial and aggressive males may require greater investment in head size/strength but such an enhancement may affect overall escape performance. Among male geckos, we found that greater biting capacity because of larger head size was associated with reduced sprint performance; this trade-off was further exacerbated when sprinting on an incline. Females, however, showed no evidence of this trade-off on either flat or inclined surfaces. The sex specificity of this trade-off suggests that the sexes differ in their optimal strategies for dealing with the conflicting requirements of bite force and sprint speed. Unlike males, female H. frenatus had a positive association between hind-limb length and head size, suggesting that they have utilised a compensatory mechanism to alleviate the possible locomotor costs of larger head sizes. It appears that there is greater selection on traits that improve fighting ability (bite force) for males, but it is viability traits (sprint speed) that appear to be of greater importance for females. Our results emphasise that only by examining both functional trade-offs and potential compensatory mechanisms is it possible to discover the varied mechanisms affecting the morphological design of a species.

The detection of vertical root fractures in root filled teeth with periapical radiographs and CBCT scans.

AIM: To compare ex vivo the diagnostic accuracy of cone beam computed tomography (CBCT) with periapical radiography in detecting artificially prepared incomplete and complete vertical root fractures (VRFs) in the presence of a gutta-percha root filling in human teeth. METHODOLOGY: The root canals of 20 extracted human premolar and molar teeth were radiographed and scanned with CBCT before a simulated VRF was induced (group 1). These teeth were radiographed and scanned with CBCT again after an incomplete (group 2) and complete (group 3) VRFs were induced. A suitably sized gutta-percha point was inserted into the prepared root canal prior to each series of radiographs and CBCT scans being taken. RESULTS: There was no improvement in the detection of artificially created vertical root fractures (VRF) in root filled teeth using CBCT compared with periapical radiographs. The overall area under the curve (AUC) value of incomplete and complete VRF was 0.53 for periapical radiography and 0.45 for CBCT (P = 0.034). The overall sensitivity of periapical radiography (0.05) was lower than CBCT (0.57) regardless of the extent of the VRF (P = 0.027). Periapical radiographs (0.98) had a higher overall specificity than CBCT (0.34) (P = 0.027). CONCLUSIONS: Under the conditions of this ex vivo study, periapical radiographs and CBCT were not accurate in detecting the presence and absence of simulated VRF. The imaging artefacts caused by the gutta-percha root filling within the root canal most probably resulted in the overestimation of VRF with CBCT and also the overall inaccuracy of this system.

Accuracy of CBCT for volumetric measurement of simulated periapical lesions.

AIM: To compare the accuracy of cone beam computed tomography (CBCT) and micro-computed tomography (µCT) when measuring the volume of bone cavities. METHODOLOGY: Ten irregular-shaped cavities of varying dimensions were created in bovine bone specimens using a rotary diamond bur. The samples were then scanned using the Accuitomo 3D CBCT scanner. The scanned information was converted to the Digital Imaging and Communication in Medicine (DICOM) format ready for analysis. Once formatted, 10 trained and calibrated examiners segmented the scans and measured the volumes of the lesions. Intra/interexaminer agreement was assessed by each examiner re-segmenting each scan after a 2-week interval. Micro-CT scans were analysed by a single examiner. To achieve a physical reading of the artificially created cavities, replicas were created using dimensionally stable silicone impression material. After measuring the mass of each impression sample, the volume was calculated by dividing the mass of each sample by the density of the set impression material. Further corroboration of these measurements was obtained by employing Archimedes' principle to measure the volume of each impression sample. Intraclass correlation was used to assess agreement. RESULTS: Both CBCT (mean volume: 175.9 mm3) and µCT (mean volume: 163.1 mm3) showed a high degree of agreement (intraclass correlation coefficient >0.9) when compared to both weighed and 'Archimedes' principle' measurements (mean volume: 177.7 and 182.6 mm3, respectively). CONCLUSION: Cone beam computed tomography is an accurate means of measuring volume of artificially created bone cavities in an ex vivo model. This may provide a valuable tool for monitoring the healing rate of apical periodontitis; further investigations are warranted.

Enhanced characterization of breast cancer phenotypes using Raman micro-spectroscopy on stainless steel substrate.

Biochemical insights into varying breast cancer (BC) phenotypes can provide a fundamental understanding of BC pathogenesis, while identifying novel therapeutic targets. Raman spectroscopy (RS) can gauge these biochemical differences with high specificity. For routine RS, cells are traditionally seeded onto calcium fluoride (CaF2) substrates that are costly and fragile, limiting its widespread adoption. Stainless steel has been interrogated previously as a less expensive alternative to CaF2 substrates, while reporting increased Raman signal intensity than the latter. We sought to further investigate and compare the Raman signal quality measured from stainless steel versus CaF2 substrates by characterizing different BC phenotypes with altered human epidermal growth factor receptor 2 (HER2) expression. Raman spectra were obtained on stainless steel and CaF2 substrates for HER2 negative cells - MDA-MB-231, MDA-MB-468 and HER2 overexpressing cells - AU565, SKBr3. Upon analyzing signal-to-noise ratios (SNR), stainless steel provided a stronger Raman signal, improving SNR by 119% at 1450 cm-1 and 122% at 2925 cm-1 on average compared to the CaF2 substrate. Utilizing only 22% of laser power on sample relative to the CaF2 substrate, stainless steel still yielded improved spectral characterization over CaF2, achieving 96.0% versus 89.8% accuracy in BC phenotype discrimination and equivalent 100.0% accuracy in HER2 status classification. Spectral analysis further highlighted increased lipogenesis and altered metabolism in HER2 overexpressing cells, which was subsequently visualized with coherent anti-Stokes Raman scattering microscopy. Our findings demonstrate that stainless steel substrates deliver improved Raman signal and enhanced spectral characterization, underscoring its potential as a cost-effective alternative to CaF2 for non-invasively monitoring cellular biochemical dynamics in translational cancer research.