Apical Sections Research Articles

Effect of different root canal disinfection protocols on push-out bond strength of two endodontic sealers

Introduction The purpose of this study was to evaluate push-out bond strength of two endodontic sealers (MetaSeal, Endosequence BC) to radicular dentin following different disinfection protocols [sodium hypochlorite (NaOCl), photoactivated disinfection, and ozonated olive oil]. Materials and methods A total of 60 freshly extracted human single rooted premolars with single root canals were selected. The crowns were removed to obtain a standardized root length of 15 mm and working length was determined. Root canals were prepared using ProTaper Universal rotary instruments up to F4 and irrigation throughout instrumentation was performed using 3 ml of 0.9% sodium chloride. Roots were randomly divided into six groups (n=10). In groups 1 and 2, root canals were finally irrigated with 3 ml of 2.5% NaOCl (as control groups), in groups 3 and 4, final disinfection protocol was performed with photoactivated disinfection, but in groups 5 and 6, root canals were finally disinfected by coating ProTaper F4 file with ozonated olive oil. In groups 1, 3, and 5, root canals were obturated with gutta-percha/MetaSeal sealer while in groups 2, 4, and 6, obturation was performed using gutta-percha/Endosequence BC sealer. Three horizontal sections were prepared in a thickness of 2 mm each corresponding to apical, middle, and coronal parts of the root. Each section was subjected to a compressive load to evaluate push-out bond strength and the data were statistically analyzed using two-way analysis of variance and post-hoc Tukey test. Results PAD groups recorded the highest values while ozonated olive oil groups recorded the lowest values. Bond strength of Endosequence BC was significantly higher than MetaSeal (P ≤ 0.05). The bond strength in the coronal sections was higher than that in the middle and apical sections. Conclusion PDA final disinfection protocol performed similarly to NaOCl and does not negatively affect bond strength as ozonated olive oil. Endosequence BC was better than MetaSeal in terms of bond strength.

Comparison of Dentinal Defects induced by Hand Files, Multiple, and Single Rotary Files: A Stereomicroscopic Study

ABSTRACT Aim This study was carried out to compare the dentinal defects induced by single rotary file system, multiple rotary file system, and hand files. Materials and methods Sixty single-rooted premolars were selected based on predetermined criteria. They were divided into three groups: Group I (hand K files), group II (Hero Shaper), and group III (One Shape). Biomechanical preparation was carried out as per the manufacturer's instructions. Each specimen was sectioned horizontally and divided into apical, middle, and coronal sections. These sections were visualized under stereomicroscope to evaluate the dentinal defects using predetermined criteria. Results Roots prepared with Hero Shaper showed more number of defects than One Shape, whereas in roots prepared with hand files lowest percentage of dentinal defects were present. There was statistically significant difference between the Hero Shaper group and the One Shape group (p < 0.05). Conclusion All rotary files induce defects in root dentin, whereas the hand instruments induce minimal defects. Clinical significance With single rotary file system, preparation time is reduced and it is easier for patients to accept the treatment. Moreover, the potential of root fracture is reduced. How to cite this article Jain A, Bhadoria K, Choudhary B, Patidar N. Comparison of Dentinal Defects induced by Hand Files, Multiple, and Single Rotary Files: A Stereomicroscopic Study. World J Dent 2017;8(1):45-48.

Evaluation of canal transportation after preparation with Reciproc single-file systems with or without glide path files.

Background:Canal transportation is a common sequel caused by rotary instruments.Aims:The purpose of the present study is to evaluate the degree of transportation after the use of Reciproc single-file instruments with or without glide path files.Methods:Thirty resin blocks with L-shaped canals were divided into three groups (n = 10). Group 1 - canals were prepared with Reciproc-25 file. Group 2 - glide path file-G1 was used before Reciproc. Group 3 - glide path files-G1 and G2 were used before Reciproc. Pre- and post-instrumentation images were superimposed under microscope, and resin removed from the inner and outer surfaces of the root canal was calculated throughout 10 points.Results:Statistical analysis was performed with Kruskal–Wallis test and post hoc Dunn test. For coronal and middle one-thirds, there was no significant difference among groups (P > 0.05). For apical section, transportation of Group 1 was significantly higher than other groups (P < 0.05).Conclusion:Using glide path files before Reciproc single-file system reduced the degree of apical canal transportation.

Comparison of the Penetration Depth of Conventional and Nano-Particle Calcium Hydroxide into Dentinal Tubules.

Introduction:The aim of this in vitro study was to evaluate and compare the penetration depth of conventional (CH) and nano-particle calcium hydroxide (NCH) into dentinal tubules. Methods and Materials:Ninety human single-rooted teeth were instrumented by RaCe rotary system and after chemomechanical preparation were randomly divided in two equal groups (n=45). In the first group conventional CH and in the other NCH was used as intracanal medicament. After 2 weeks of incubation all roots were intentionally split at longitudinal axis and prepared for scanning electron microscope (SEM) observation. Three zones of each root, coronal, middle and apical were examined under SEM and the maximum penetration depth of the dressing material into dentinal tubules was recorded for each zone. Data were analyzed using the independent sample t test and the level of significance was set at 0.05. Results:In all of the three zones, NCH group had greater penetration depth than CH (P<0.001). In both groups the penetration depth increased from the apical section to the coronal.Conclusion:The depth of penetration of nano-particle calcium hydroxide into the dentinal tubules was significantly higher than that of conventional calcium hydroxide. The lowest penetration depth was observed in apical zone in both groups.

Scanning Electron Microscopic Evaluation of the Sealer-Dentine Interface of Three Sealers.

Introduction:This study aimed to evaluate the dentine-sealer interface in three different sealers using scanning electron microscopy (SEM). Methods and Materials:Thirty extracted human single-rooted teeth were prepared using ProTaper rotary files and were randomly divided into three groups (n=10) including BC Sealer, AH-Plus and Dorifill. The root canals were filled with cold lateral condensation technique and stored for 7 days in 100% humidity at 37°C. Cross sections were prepared from the coronal, middle, and apical sections of the roots. Then SEM images were taken and the width of gaps was measured by software. Sectional images were evaluated by two endodontists. Data were analyzed using two- and one-way ANOVA and Kruskal-Wallis tests. Results:The mean gap width was significantly lower in coronal area in BC Sealer group compared to Dorifill (P=0.043) and likewise in AH-Plus group compared to Dorifill (P=0.018). There was no significant difference between BC Sealer and AH-Plus group in this area (P=0.923). No significant difference was detected in apical and middle zones among three sealers (P=0.367 and 0.643, respectively). Dentine-sealer interface showed no significant difference in three sealers in the apical area (P=0.051), but dentine-BC Sealer interface was better than AH-Plus in middle and coronal areas, and both outperformed Dorifill (P=0.001). Conclusion:BC Sealer and AH-Plus had less gaps than Dorifill in coronal area. In addition, BC Sealer had better dentine interface in middle and coronal area compared to AH-Plus, and both performed better than Dorifill. Reverse relationship was observed between the mean gap width and dentine-sealer interface quality.

Giant Cell Myocarditis: A Brief Review.

Giant cell myocarditis (GCM) is a rapidly progressive and frequently fatal disease that mainly affects young to middle-aged previously healthy individuals. Early diagnosis is critical, as recent studies have shown that rapidly instituted cyclosporine-based immunosuppression can reduce inflammation and improve transplant-free survival. Before the 1980s, GCM was mainly a diagnosis made at autopsy. Owing to advancements in diagnostic and therapeutic options, it is now increasingly diagnosed on the basis of endomyocardial biopsies, explanted hearts, or apical wedge sections removed at the time of ventricular assist device placement. Histologic examination remains the gold standard for diagnosis; however, there are many possible etiologies for cardiac giant cells. Having a working knowledge of the clinicopathologic features that distinguish GCM from other giant cell-containing lesions is essential, since such lesions can have widely divergent management and outcome.

Striated Muscle in Radical Prostatectomy Specimens: A Marker of Apical Dissection Quality and an Independent Predictor of Urinary Continence after Endoscopic Extraperitoneal Radical Prostatectomy

Introduction: The study aimed to determine if the presence and amount of striated muscle on the apical sections of the cruciate sections of laparoscopic radical prostatectomy (LRP) specimens predict early and long-term urinary continence outcomes. Patients and Methods: We conducted a retrospective review of our prospectively collected single surgeon LRP database. We identified patients based on their continence outcomes (continent (0 pads) or incontinent at 12 months), with an approximate even spread early continent and incontinent patients). An uropathologist separate from the urology team was blinded to outcome and assessed each patients' apical cruciate sections (H&E stained) for the presence, percentage and maximal diameter of muscle and extraprostatic tissue on these sections. Specifically 2 scoring systems were used: (1) semi-quantitative estimation of percentage of muscle on the apical cruciate sections (low <5% and high >5%) and (2) percentage of total extraprostatic tissue on cruciate section (low <10% and high >10%). Logistic regression and classification and regression tree analyses were performed to identify the predictors of urinary incontinence (UI). Results: In total 80 patients were analyzed, 38 were continent and 42 were incontinent at 12 months follow-up. The percentage of extraprostatic tissue/muscle being an independent predictor of being wet at 12 months (p = 0.002) on multivariate regression along with age (p = 0.04). Using percentage of extraprostatic tissue in cruciate section (high >10%) to predict UI at 12 months, it yielded 71% sensitivity, 82% specificity, 81% PPV, 72% NPV and 76% accuracy. Conclusion: The use of simple additional reporting of muscle and extraprostatic tissue on the apical sections of RP specimens can help to better predict the likelihood of continence return.

A new genus and species of Tettigarctidae from the Mesozoic of northeastern China (Insecta, Hemiptera, Cicadoidea).

A new genus Maculaprosbole of Tettigarctidae with a new species Maculaprosbole zhengi is described based on a complete fossil forewing from the Mesozoic of northeastern China. Due to its broad costal area and clavus, Maculaprosbole zhengi gen. et sp. n. can be attributed to the subfamily Cicadoprosbolinae. This genus is similar to the genera Sanmai and Hirtaprosbole in coloration pattern and forewing venation, respectively. However, it differs from Hirtaprosbole in crossvein r-m absent and apical CuA section strongly curved, running along the nodal line for a distance, and Sanmai in transverse coloration mainly focusing on the postnodal area. Herein, the prominent coloration pattern of this new taxon is discussed.

Evaluation of bond strength of various epoxy resin based sealers in oval shaped root canals.

BackgroundThe aim of this study was to evaluate the bond strength of AH plus, Acroseal, and Adseal to the root canal dentin.MethodsA total of 36 single-rooted, mandibular premolar teeth were used. Root canal shaping procedures were performed with ProTaper rotary instruments (Dentsply Maillefer) up to size F4. The prepared samples were then randomly assembled into 3 groups (n = 12). For each group, an ultrasonic tip (size 15, 0.02 taper) which was also coated with an epoxy resin based sealer and placed 2 mm shorter than the working length. The sealer was then activated for 10 s. A push-out test was used to measure the bond strength between the root canal dentine and the sealer. Kruskal-Wallis test to evaluate the push-out bond strength of epoxy based sealer (P = 0.05). The failure mode data were statistically analyzed using Pearson’s chi square test (P = 0.05).ResultsKruskal-Wallis test indicated that there were no statistically significant difference among the push out bond strength values of 3 mm (p = 0.123) and 6 mm (P = 0.057) for groups, there was statistically significant difference push out bond strength value of 9 mm (P = 0.032). Pearson’s chi square test showed statistically significant differences for the failure types among the groups.ConclusionVarious epoxy resin based sealers activated ultrasonically showed similar bond strength in oval shaped root canals. Apical sections for all groups have higher push out bond strength values than middle and coronal sections.Electronic supplementary materialThe online version of this article (doi:10.1186/s12903-016-0301-1) contains supplementary material, which is available to authorized users.

Apical hair cell degeneration causes the increase in the amplitude of summating potential

Conclusion: This study indicates that the lesion of hair cells in the apical turn of the cochlea can cause the change in the summating potential (SP)/Compound potential (CAP) ratio.Objectives: Electrocochleography is a valuable clinic test for diagnosis of cochlear pathologies and the ratio of SP to CAP has been used to identify Meniere’s disease. However, it remains controversial whether the increase of the SP/CAP ratio represents exclusively the endolymphatic hydrops.Method: This study measured the SP and CAP in mice that displayed outer hair cell (OHC) degeneration in the apical section of the cochlea as their age increased.Results: As compared with the mice aged 8–10 months, the 24-month old mice displayed a significant increase in the amplitude of SP at 12–16 kHz. This result suggests that the degeneration of OHCs in the apical turn leads to the increase of the + SP at the middle frequencies. In contrast, the aging mice did not have a significant change in the CAP amplitude at super-threshold levels.

Description of Trithornus aquatica gen. n. sp. n. (Nemtoda:Cephalobina) from aquatic habitat, India.

Abstract: A new cephalobid nematode, Trithornus aquatica gen. n. sp. n. has been described and illustrated. The new genus can be distinguished by the unique shape of its labial probolae, consisting of swollen labial shaft and a trifurcated apical section. The cephalic probolae is triangular in shape. Cuticle is transversely annulated, lateral field with five incisors, outer ones being undulate. The stoma comprises of cheilostom with granular rhabdia, gymnostom narrower than cheilostom and stegostom. Stegostome can be differentiated into three parts meta, meso and telo. A tooth is present on mesostegostome. Females have cephaloboid type of reproductive system. Tail is elongate conoid with a pointed tip. Males were not found. The newly described genus closely resembles Acrobeles Linstow, 1877, Chiloplacus Thorne, 1937 and Cervidellus Thorne, 1937 in having similar stoma, furcated labial probolae, simple cuticle and cephaloboid type of female gonad with a post uterine sac. But, is clearly distinguishable by the related genera on the basis of the shape of labial probolae and the presence of outer undulated lateral lines. A dichotomous key to the identification of the genus has also been provided.

Limited effect of gizzard sand on consumption of the macrophyte Myriophyllum spicatum by the great pond snail Lymnaea stagnalis

The sand stored in the gizzard of some freshwater snails should assist in the mechanical digestion of tough food, yet effects of gizzard sand on consumption of living macrophyte tissue are seldom addressed. We quantified the effects of gizzard sand both on consumption of plant tissue and on snail growth and reproduction with a cross-gradient, 28-day laboratory experiment. We offered apical shoot sections of Myriophyllum spicatum (initial ash content ~ 56%) or soft lettuce (ash content ~ 19%, as control) to Lymnaea stagnalis previously reared on sand or without sand. Gizzard sand had no effect on snail growth but sand-reared snails fed with lettuce initially produced more eggs than their no-sand counterparts. Snails fed M. spicatum exhibited stunted growth and produced only one small egg clutch. Shell height at time of first oviposition of M. spicatum-fed snails was two-thirds of that of lettuce-fed controls. Snails initially appeared to feed on periphyton and older, brownish M. spicatum leaflet tips, but later turned to midstem tissue. Fresh apices were not consumed. Gizzard sand had a limited effect on the ability of L. stagnalis to consume living M. spicatum, with apices likely defended chemically (polyphenols) and midstem tissue defended structurally (high ash content).

Effects of clonal integration on the invasive clonal plant Alternanthera philoxeroides under heterogeneous and homogeneous water availability.

Many notorious invasive plants are clonal, living in heterogeneous or homogeneous habitats. To understand how clonal integration affects the performance of these plants in different habitat conditions, an 8-week greenhouse experiment was conducted: ramet pairs of A. philoxeroides were grown in two habitats, either heterogeneous or homogeneous in water availability, with the stolon connections either severed or kept intact. Under heterogeneous water availability, compared with ramets in homogeneous habitats, clonal integration significantly promoted the growth and photosynthetic performance of water-stressed apical ramets, whereas it only increased the photosynthetic performance but did not affect the growth of water-stressed basal ramets. Moreover, clonal integration markedly increased the root/shoot ratios of ramets grown in habitats with high water supply but decreased it under low water availability. Under homogeneous water availability, stolon connection (clonal integration) did not influence the growth, photosynthetic performance and biomass allocation of water-stressed ramets, but it significantly promoted the growth of well-watered ramets in both apical and basal sections. These findings deepen our understanding of the bidirectional and differentiated (mainly acropetal) clonal integration of A. philoxeroides, suggesting that the invasive plant A. philoxeroides can benefit from clonal integration in both heterogeneous and homogeneous habitats.

A Micro–Computed Tomographic Assessment of the Influence of Operator's Experience on the Quality of WaveOne Instrumentation

IntroductionMicro–computed tomographic scanning was used to evaluate the influence of operator's experience on the time and quality of instrumentation of the mesial root canals of mandibular molars using WaveOne Primary files (Dentsply Maillefer, Ballaigues, Switzerland). MethodsThirty mandibular molars with 2 separate mesial canals were submitted to preoperative micro-CT scans. Teeth were randomly allocated to 3 groups: and experienced operator group and inexperienced groups before and after training with WaveOne files. Second scans were obtained after instrumentation. The volume of the untreated canal, the volume of dentin removed after preparation; the amount of the uninstrumented area; and transportation to the coronal, middle, and apical thirds of canals were measured. The preparation time was also recorded. ResultsInstrumentation of canals increased their volume and surface area in all groups. No significant differences between experienced and inexperienced (with and without training) groups in the apical, middle, and coronal sections were detected although coronal transportation was slightly larger in both inexperienced groups than in the experienced group. The inexperienced operator without training used significantly more time for instrumentation than the experienced operator (P < .05); after training for 1 month, the instrumentation time by the same inexperienced operator was reduced (P < .05) to close to the time of the experienced operator (P > .05). ConclusionsThe WaveOne instrumentation technique required a short learning curve for the inexperienced user in order to master this technology.

Reproductive biology of the black coral Antipathella wollastoni (Cnidaria: Antipatharia) in the Azores (NE Atlantic)

Antipathella wollastoni is an antipatharian species common to Macaronesia, occurring in depths between 20 and 1425m. Despite its importance as a habitat-forming species, there is no information about its basic biology. The aim of the current study is to describe its reproductive strategy, gametogenic cycle and reproductive timing. Sampling was performed monthly on six tagged colonies during one year and specimens were histologically processed. A. wollastoni was found to be a gonochoric broadcast spawner. Gametogenesis took place within the primary transversal mesenteries, and followed an annual cycle. The reproductive season coincided with an increase in seawater temperature but spawning, inferred from the disappearance of gametes, likely happened after the sea surface temperature peak of the year (September 2009). Polyp fecundity ranged from 1 to 309 oocytes/polyp. A decrease in polyp fecundity was detected in samples at the higher pre-spawning maturity stage, indicating possible repetitive spawning or oocyte absorption. Intra-colonial comparisons revealed a longer duration of the reproductive cycle in the medial colony section, and a gradient of increased oocyte size towards the apical section, possibly due to intra-colonial differences in energy allocation between reproduction and other biological processes, or as a strategy against predation on gametes/larvae. Colony height was positively correlated with polyp fecundity indicating that the reproductive output increases with colony size.

Penetration Depth of Sodium Hypochlorite in Dentinal Tubules after Conventional Irrigation, Passive Ultrasonic Agitation and Nd:YAG Laser Activated Irrigation

The penetration depth of irrigating solutions in dentinal tubules is limited; consequently, bacteria can remain inside dentinal tubules after the cleaning and shaping of the root canal system. Therefore, new irrigation systems are required to increase the penetration depth of irrigating solutions in dentinal tubules. A comparative study regarding the penetration depth of sodium hypochlorite (NaOCl) solution in dentinal tubules using four methods, (1) conventional irrigation (CI), (2) smear layer removal plus conventional irrigation (gold standard), (3) passive ultrasonic agitation (PUA) and (4) Nd:YAG laser activated irrigation (LAI), took place on 144 extracted mandibular teeth with a single root canal. After decoronation with a diamond disc and working length determination, the apical foramen was sealed with wax. The canals were prepared up to #35 Mtwo rotary file and 5.25% NaOCl was used for irrigation during preparation. To study the penetration depth of NaOCl, smear layer was eliminated in all samples. Dentinal tubules were stained with crystal violet and after longitudinal sectioning of teeth, the two halves were reassembled and root canal preparation was performed up to #40 Mtwo rotary file. Then the samples were distributed into four experimental groups. Depth of the bleached zone was evaluated by stereomicroscope (20X). Data were analyzed by Kruskal-Wallis test. The highest and lowest average for NaOCl penetration depth in all three coronal, middle and apical sections belonged to CI + smear layer removal and CI. A statistically significant difference was seen when comparing the penetration depth of CI + smear layer removal group to CI and PUA groups in coronal and middle third, in which the average NaOCl penetration depth of the gold standard group was higher (P < 0.05). A statistically significant difference was seen between CI + smear layer removal group and the other three groups including CI, PUA and LAI in apical third, in which the average NaOCl penetration depth in the gold standard group was higher (P < 0.001). The standard protocol for smear layer removal led to more effective smear layer elimination and deeper penetration depth of irrigation solutions. PUA and LAI groups exhibited less smear layer elimination and penetration depth of irrigation solutions. Therefore, CI+smear layer removal should still be considered as the gold standard.

Expression analysis of stem prickle formation in blackberry using cDNA-AFLP

To understand the molecular mechanism of prickle formation in blackberry, differential expression profile of cDNA between 'Boysenberry' blackberry and its thin-thorn mutant were analysed by using cDNA-AFLP. In total, 256 primer pairs were used for the cDNA-AFLP amplification to produce 45 differentially expressed fragments. The putative function of the sequenced fragments was determined using BLAST analysis. Putative functions included metabolism, signal transduction, cell skeleton and composition, transcriptional regulation and adversity defence. A 109 bp fragment was found to have an 88% sequence homology with a strawberry TRY transcription factor, which inhibits trichome development in Arabidopsis. A 124 bp fragment had a 75% homology with alfalfa cell wall hydrolase gene. This fragment was named Ruh and had higher expression in shoot apical meristem (SAM), middle and upper section of stem of thin-thorn mutant. This implied that the prickle formation was an intricate system and the sense of expression pattern of cell wall-associated hydrolase homologous gene Ruh in the thin-thorn mutant needs further investigation.

Exploring natural variation of Pinus pinaster Aiton using metabolomics: Is it possible to identify the region of origin of a pine from its metabolites?

Natural variation of the metabolome of Pinus pinaster was studied to improve understanding of its role in the adaptation process and phenotypic diversity. The metabolomes of needles and the apical and basal section of buds were analysed in ten provenances of P.pinaster, selected from France, Spain and Morocco, grown in a common garden for 5years. The employment of complementary mass spectrometry techniques (GC-MS and LC-Orbitrap-MS) together with bioinformatics tools allowed the reliable quantification of 2403 molecular masses. The analysis of the metabolome showed that differences were maintained across provenances and that the metabolites characteristic of each organ are mainly related to amino acid metabolism, while provenances were distinguishable essentially through secondary metabolism when organs were analysed independently. Integrative analyses of metabolome, environmental and growth data provided a comprehensive picture of adaptation plasticity in conifers. These analyses defined two major groups of plants, distinguished by secondary metabolism: that is, either Atlantic or Mediterranean provenance. Needles were the most sensitive organ, where strong correlations were found between flavonoids and the water regime of the geographic origin of the provenance. The data obtained point to genome specialization aimed at maximizing the drought stress resistance of trees depending on their origin.

Comparative assessment of the area of sealer voids in single cone obturation done with mineral trioxide aggregate, epoxy resin, and zinc-oxide eugenol based sealers

Introduction: Voids in the sealer mass have the potential to allow leakage through obturation. They are more critical in single cone (SC) obturation as the volume of sealer used in this obturation is larger when compared to other obturations. Aim: To compare the area of voids in mineral trioxide aggregate (MTA)-based, resin-based, and zinc oxide-eugenol-based sealers when employed with SC obturation technique. Materials and Methods: Fifteen teeth were cleaned and shaped and divided into three groups for SC obturation using MTA Fillapex, AH26, and Pulpdent sealers, respectively. The obturated teeth were sectioned at apical, middle, and coronal third, and area of voids in the sealer was assessed using a stereomicroscope and digital images and image software. The results were statistically analyzed using SPSS software and Kruskal-Wallis and Mann-Whitney tests. Results: The three tested sealers showed voids in all the sections except MTA Fillapex, which was void free in apical and middle sections. There were significant differences between these sealers regarding their section wise area of voids (P < 0.05). Similarly, there were significant differences in their overall area of voids (P < 0.05) with MTA Fillapex showing significantly least area of voids followed by AH26. Conclusions: SC obturation with MTA Fillapex sealer, which showed void free apical and middle third sections, had significantly least area of voids in the sealer followed by the one with AH26 sealer, whereas SC obturation with Pulpdent sealer had significantly most area of voids.

Degree of conversion of a self-adhesive endodontic sealer when used as bulk material.

This study tested the null hypothesis that the opacity of RealSeal SE (RSSE) sealer makes light-curing inefficient, while the degree of conversion (DC) is similar regardless of curing method. Fourteen uniradicular teeth were sectioned at 15 mm from the apex. Root canals were instrumented using the Reciproc file system, bulk-filled with RSSE, and divided randomly into two groups (dual-cure or self-cure). DC was determined by micro-Raman spectroscopy at 24 h, 48 h, and 1 week after filling, at 6, 9, and 12 mm from the coronal end. Contrast ratio (Yb/Yw) was used to determine the opacity of the material. Descriptive statistics and nonparametric tests were used, and significance was defined as a P value of less than 0.05. Opacity was almost total by the first section, at 6 mm. In dual-cure mode, DC values at 24 h were lower in the apical section (63.8%) than in the more coronal sections and were lower than in self-cured specimens (87.4%). Light-curing of the coronal end did not improve DC. These differences remained at 48 h and 1 week. Only a small (2%) but significant increase in DC was observed in evaluations at 24 h and 1 week. (J Oral Sci 58, 333-338, 2016).