Canal Surface Research Articles

An exploratory study of pelvis anatomy to revise the bony canal used for LC2 screw insertion

BackgroundPercutaneous screw placement, especially the insertion of LC2 screws, is technically demanding. Although the traditional LC2 bony canal spans the anterior inferior iliac spine (AIIS) to the posterior superior iliac spines (PSIS), a high perforation rate has been reported.ObjectionThe aim of this research was to design a revised bony canal, measure the canal width and length and guide the insertion of LC2 screws for pelvic fractures.Materials and methodsThe plane tool in the Mimics analysis menu was used to draw a midplane connecting the midpoint between the anterior inferior spine and the PSIS upper flat region with pelvic CT data. The minimum widths of the upper, middle, lower surfaces of the tunnel and perforation rate were measured and compared. The ideal screw length was also measured along the longitudinal axis running through the midpoint of the midplane.ResultsThe minimum widths of the upper, middle and lower surfaces of the revised canal were 3.63 mm, 7.7 mm, and 11.93 mm, respectively, in males and 5.97 mm, 9.93 mm, and 12.45 mm, respectively, in females. Significant differences were observed among the upper, middle and lower surfaces of the revised canal in male patients (P < 0.001). In female subjects, the upper canal surface was significantly different from the middle and lower canal surfaces (P < 0.001). The perforation rate was significantly decreased especially in females pelvic. The channel length passing through the midpoint of the narrowest position of the pelvis was 130.85 ± 8.02 mm in males and 124.30 ± 7.71 mm in females and was significantly different for male and female pelvises (P = 0.004).ConclusionThe LC2 screw should be inserted along the intersection line of the AIIS lateral wall and the iliac body. The screw should be inserted under the line between the midpoint of the AIIS and the PSIS upper flat region to ensure accuracy of placement. LC2 screws can be more easily inserted in males than in females, and the rate of cortical perforation can be significantly decreased under the guidance of the newly proposed canal.

Effect of Access Cavity Preparation on Dentin Preservation, Biomechanical Property, and Instrumentation Efficacy: A Micro–Computed Tomographic Study

IntroductionThe purpose of this study was to evaluate the influence of a contracted endodontic cavity (CEC) on dentin preservation, biomechanical property, and instrumentation efficacy of first permanent molars in comparison with a traditional endodontic cavity (TEC). MethodsForty-eight extracted intact maxillary and mandibular first molars were selected and scanned by micro–computed tomographic (micro-CT) imaging. Each tooth type was anatomically matched and assigned to the CEC group or the TEC group (n = 12). After root canal instrumentation with the ProGlider (Dentsply Maillefer, Ballaigues, Switzerland) and WaveOne Gold (Dentsply Maillefer), the specimens were scanned by micro-CT again. Pre- and postpreparation micro-CT imaging was used to evaluate the dentin preservation and instrumentation efficacy. The results on volume and thickness reduction in the coronal dentin and pericervical dentin (PCD), root canal volume and surface area, percentage of unprepared surface area, canal transportation and centering ratio, and canal wall thickness in the “danger zone” were measured and analyzed with the Shapiro-Wilk and independent sample t tests. Based on micro-CT imaging of maxillary and mandibular first molars, CEC and TEC models were constructed on the intact tooth, and 2 different static loads were applied to the occlusal load points. The stress distribution patterns and von Mises stress on the occlusal surface and cervical region were assessed by 3-dimensional finite element analysis. ResultsThe CEC had a significantly lower volume and thickness reduction of coronal dentin and PCD above the alveolar crest compared with the TEC group (P < .05), whereas no difference was observed in PCD below the alveolar crest between the 2 groups (P > .05). There was no difference regarding all instrumentation efficacy outcomes (root canal volume and surface area, percentage of unprepared surface area, canal transportation and centering ratio, and canal wall thickness) in the danger zone between the 2 groups (P > .05). The CEC effectively reduced the maximum von Mises stress and stress concentration area on the occlusal surface and cervical region compared with the TEC. ConclusionsThe CEC preserved more coronal dentin and PCD above the alveolar crest and thus reduced stress concentration on the occlusal surface and cervical region. The CEC had no significant adverse effects on the instrumentation efficacy compared with the TEC given that the instrumentation procedures were performed with ProGlider and WaveOne Gold files.

Influence of the Number of Pecking Motions at Working Length on the Shaping Ability of Single-file Systems in Long Oval-shaped Curved Canals

IntroductionThe present study compared the effect of the number of pecking motions at the working length (WL) on the shaping ability of single-file systems in long oval-shaped curved root canals. MethodsSingle-rooted mandibular premolars with long oval-shaped curved canals (25°–35°) were prescanned using micro–computed tomographic imaging, anatomically paired, and randomly divided into 3 groups (n = 15): XP-endo Shaper (XPS; FKG Dentaire, La Chaux-de-Fonds, Switzerland), Reciproc Blue (RB; VDW, Munich, Germany), and WaveOne Gold (WOG; Dentsply Sirona, Ballaigues, Switzerland). After preparation to the WL, each specimen underwent 1, 2, 4, 10, or 20 pecking motions to the WL and was rescanned. Morphologic parameters were measured and analyzed using a 2-factor repeated measures analysis of variance and the Scheirer-Ray-Hare test. ResultsThe minor apical diameter and percentage increase in canal volume increased with the number of pecking motions, whereas the percentage of unprepared canal surface area decreased (P < .05). The mean minor diameters (in mm) at D0 varied between 0.29 and 0.35 after 4 pecking motions with the RB and WOG systems and between 0.35 and 0.36 after 10 pecking motions with the XPS system. No significant differences in canal transportation or centering ratio were observed among the groups at the levels of canal curvature and canal thirds (P > .05). ConclusionsIncreasing the number of pecking motions improves the cutting efficacy of single-file systems without adversely altering the anatomic characteristics of oval-shaped curved canals. No more than 4 pecking motions for the RB and WOG systems and 10 pecking motions for the XPS system appear to be acceptable for the shaping of these difficult to clean root canals.

The potential of high molecular chitosan nanohydroxyapatite as an irrigant in improving fracture resistance after root canal treatment (In Vitro)

ABSTRACT Teeth after root canal treatment are at a higher risk of fracture than vital teeth. After root canaltreatment, the causes of tooth fracture are multifactorial, both iatrogenic and non iatrogenic. One of them isirrigants, although very useful for disinfection. Irrigants are known to change the chemical components andstructure of the root canal surface dentin by modifying the proportion of calcium and phosphate minerals. Thisresearch is an experimental laboratory study with a post-test-only group research design to analyze the effect ofirrigating solutions of nanohydroxyapatite, high molecular chitosan, NaOCl, and EDTA with their appropriatecombination for the test group on the fracture resistance of teeth after root canal treatment. Root canal treatment wasperformed on 24 mandibular premolars, with the group I; irrigating solution of nanohydroxyapatite, group II;irrigation of nanohydroxyapatite solution with the addition of 0.2% chitosan, group III; irrigation with 2.5% NaOClsolution and 0.2% chitosan solution, group IV; irrigation solution of 2.5% NaOCl and 17% EDTA. ANOVA testshowed a significant difference in fracture resistance (p0.05) between each group. The highest average fractureresistance was seen in group II, namely the irrigation group using a solution of nanohydroxyapatite with theaddition of 0.2% chitosan, which was 363.644 ± 10,896 N. fracture after root canal treatment.KEYWORDS: nanohydroxyapatite, irrigation solution, fracture resistance

The effectiveness of nano-chitosan high molecular 0.2% as irrigant agent against Enterococcus faecalis with passive ultrasonic irrigant.

Context:Enterococcus faecalis is the microorganism most frequently associated with failure of endodontic treatment. Chitosan is an irrigant in dentistry has the properties of biocompatibility, biodegradability, bioadhesion, and not toxic to human cells. Several studies have suggested the use of ultrasonics to enhancing the action of irrigants.Aims:The aim of the study was to investigate the bacterial growth and surface roughness of the root canal surface after irrigation and agitation with passive ultrasonic irrigant.Subjects and Methods:Experimental research with randomized block design obtained a sample size for each group of 9 samples with a total number of 27 teeth divided into three treatment groups. Statistical analysis used was one-way analysis of variance.Results:The irrigation material for nano-chitosan high molecular 0.2% with passive ultrasonic irrigation (PUI) activation was shown to cause lysis on surface of bacterial cell walls. There was no significant difference between the roughness values in all treatment groups.Conclusions:The irrigation of root canal treatment with 0.2% high molecular nano-chitosan with the addition of PUI activation had significant antibacterial activities against E. faecalis.

Shaping ability of modern Nickel-Titanium rotary systems on the preparation of printed mandibular molars.

This study aimed to evaluate the shaping ability of TruNatomy (Dentsply Maillefer, Ballaigues, Switzerland), VDW.ROTATE (VDW GmbH, Munich, Germany) and ProTaper Gold (Dentsply Maillefer, Ballaigues, Switzerland) during the preparation of resin-printed mandibular molar mesial root canals. Thirty-three printed resin-based mandibular mesial roots with two canals were obtained from extract tooth cone-beam computed tomography (CBCT) image. The printed teeth were divided into three groups (n = 11) according to the system used for root canal preparation: TruNatomy, VDW.ROTATE, and ProTaper Gold. The specimens were scanned using CBCT imaging before and after root canal preparation. Then images were registered using a dedicated software and changes in the canal area, volume, untouched canal surface, and the maximum and minimum dentin wall wear were calculated. Data were statistically analyzed using Shapiro-Wilk for normality, one-way ANOVA, and Tukey or Kruskal-Wallis H tests with alpha set at 5%. No differences were observed for changes in the canal area, volume, untouched canal surface area, and minimum dentine wall wear parameters for the whole canal length (P > 0.05). The mean of untouched canal surface area for the TruNatomy, VDW.ROTATE, and ProTaper Gold was 40%, 44%, and 44%, respectively. The maximum dentine wall wear was significantly lower in the ProTaper Gold group than in the TruNatomy and VDW.ROTATE groups (P < 0.05). TruNatomy, VDW.ROTATE, and ProTaper Gold systems showed similar shaping ability in printed resin-based mandibular mesial roots without clinically significant errors. A large amount of untouched canal surface area was observed for all systems.

Comparison of five rotary systems regarding design, metallurgy, mechanical performance, and canal preparation-a multimethod research.

To compare the design, metallurgy, mechanical performance, and canal preparation of 5 rotary systems. A total of 735 25-mm NiTi instruments (sizes 0.17[0.18]/.02v, 0.20/.04v, 0.20/.07v, 0.25/.08v, 0.30/.09v) from ProTaper Gold, ProTaper Universal, Premium Taper Gold, Go-Taper Flex, and U-File systems were compared regarding overall geometry and surface finishing (stereomicroscopy and scanning electron microscopy), nickel and titanium ratio (energy-dispersive spectroscopy), phase transformation temperatures (differential scanning calorimetry), mechanical performance (torsional and bending tests), and unprepared canal surface (micro-CT). One-way ANOVA and Mood's median tests were used for statistical comparisons with a significance level set at 5%. Stereomicroscopic analysis showed more spirals and high helical angles in the Premium Taper Gold system. All sets of instruments had symmetrical spirals, no radial lands, no major defects, and an almost equiatomic ratio between nickel and titanium elements, while differences were observed in their tips' geometry and surface finishing. At room temperature (20°C), DSC test revealed martensitic characteristics for ProTaper Gold and Go-Taper Flex, and mixed austenite plus R-phase for the Premium Taper Gold, while ProTaper Universal and U-Files had full austenitic characteristics. Overall, larger instruments had higher torque resistance and bending load values than smaller ones, while a lack of consistency and mixed values were observed in the angle of rotation. The 0.25/.08v and 0.30/.09v instruments of ProTaper Universal and U-File had the highest maximum torques, the lowest angles of rotation, and the highest bending loads than other tested systems (P < .05). No significant difference was noted regarding the untouched root canal walls after preparation with the tested systems (P > .05). Although differences observed in the overall geometry and phase transformation temperatures have influenced the results of mechanical tests, unprepared canal surface areas were equivalent among systems. Root canal preparation systems with similar geometries might present different mechanical behaviors but equivalent shaping ability.

A Qualitative Exploration in Causes of Water Insecurity Experiences, and Gender and Nutritional Consequences in South-Punjab, Pakistan.

Although water insecurity has been discussed in general, its impacts on mothers’ physical and mental health, and infants’ and young children’s feeding (IYCF), has largely been ignored. This study explores household water insecurity experiences and their association with optimal health and nutrition of women and children in the Rajanpur district of Punjab Province. Using focus group discussions (FGDs) and key informants (KIIs) interviews from an area with high maternal-child malnutrition prevalence, a qualitative study was conducted to describe local experiences of water acquirement and arrangement, and of the consequences of water insecurity. The findings highlight that rural Western marginalized populations of the Rajanpur district rely on brackish, canal, or flood surface water as the water supply is absent, which intensifies mothers’ work burden and stress, and often makes them victims of violence, stigma, and sickness. Water fetching impacts women in unforeseen ways, impacting the psychosocial and physical health of mothers engaged in maternal breastfeeding. Water insecurity, originally rooted in regional disparities, compounds with gender inequities, which leads to maternal stress and child sickness. Justice in water resources is imperative and urgent in the deprived South of Punjab province for improving public health nutrition.

Retraction Note to: Correlation of hydromyelia with subarachnoid hemorrhage–related hydrocephalus: an experimental study

Although the central canal is an integral component of the cerebral ventricular system, central canal dilation has not been examined adequately during the progression of subarachnoid hemorrhage–related hydrocephalus (SAH-H). Central canal dilation–associated ependymal cell desquamation or subependymal membrane rupture has been rarely reported. Herein, we try to describe possible mechanisms of central canal dilation “Hydromyelia,” developing after SAH. A total of 25 New Zealand hybrid female rabbits were recruited. Five served as controls, and five received sham operations. In the remaining animals (n = 15), 0.5 mL/kg of autologous blood was injected into the cisterna magna twice on 0 and 2nd days. Five of these animals died within a few days. A total of 10 survivor animals decapitated 3 weeks later, and the brains and cervical spinal cords were histologically examined. Central canal volumes, ependymal cell numbers on the canal surfaces, and the Evans’ indices of the ventricles were compared. On histological examination, central canal occlusion with desquamated ependymal cells and basement membrane rupture were evident. The mean Evans’ index of the brain ventricles was 0.31, the mean central canal volume was 1.054 mm3, and the normal ependymal cell density was 4.210/mm2 in control animals; the respective values were 0.34, 1.287 mm3, and 3.602/mm2 for sham-operated animals, and 0.41, 1.776 mm3, and 2.923/mm2 in the study group. The differences were statistically significant (p < 0.05). Hydromyelia, an ignored complication of SAH-H, features ependymal cell desquamation, subependymal basement membrane destruction, blood cell accumulation on the subependymal cell basement membrane, and increased CSF pressure. Hydromyelia may be a significant complication following SAH.

339 The Glasgow Lumbar Spinal Stenosis Scale: An Individualised Measurement Formula for the Radiological Assessment of Lumbar Spinal Stenosis

Abstract Background Lumbar spinal stenosis (LSS) is a common spinal problem. Currently there is no universally accepted quantitative approach to the radiological measurement of LSS. Quantitative descriptions do exist, but these are unidimensional and do not consider normal variation in anatomy. We propose a universal and individualised measurement system for the quantitative radiological assessment of lumbar spinal stenosis. Method A retrospective case series of patients who had undergone surgery for symptomatic lumbar spinal stenosis over a 3-year period. Pre-operative T2 weighted lumbar spine MRI were analysed. Each patient had the degree of lumbar canal stenosis quantified using our approach. Results Our novel formula for the quantitative radiological assessment of LSS is two dimensional, repeatable, and presented as a percentage, to correct for the individual patient. The surface area of the canal at the level of stenosis is measured (mm2). The adjacent 2 levels are then measured and averaged. The calculation becomes (A-S/A) x 100 = R, where S is the canal surface area at the stenosed level, A is the average canal surface area of the two levels adjacent to the level of interest and R is the relative degree of lumbar spinal canal stenosis expressed as a percentage. Conclusions This novel quantitative measurement formula for the radiological assessment of lumbar canal spinal stenosis is quick and simple to calculate and most importantly adjusts for the individual patient’s normal or degenerative anatomy. This new measurement tool will need validation against specific clinical and operative criteria in the future.

G3 Shape Adjustable GHT-Bézier Developable Surfaces and Their Applications

In this article, we proposed a novel method for the construction of generalized hybrid trigonometric (GHT-Bézier) developable surfaces to tackle the issue of modeling and shape designing in engineering. The GHT-Bézier developable surface is obtained by using the duality principle between the points and planes with GHT-Bézier curve. With different shape control parameters in their domain, a class of GHT-Bézier developable surfaces can be established (such as enveloping developable GHT-Bézier surfaces, spine curve developable GHT-Bézier surfaces, geodesic interpolating surfaces for GHT-Bézier surface and developable GHT-Bézier canal surfaces), which possess many properties of GHT-Bézier surfaces. By changing the values of shape parameters the effect on the developable surface is obvious. In addition, some useful geometric properties of GHT-Bézier developable surface and the G1, G2 (Farin-Boehm and Beta) and G3 continuity conditions between any two GHT-Bézier developable surfaces are derived. Furthermore, various useful and representative numerical examples demonstrate the convenience and efficiency of the proposed method.

The glasgow lumbar spinal stenosis scale: an individualised measurement formula for the radiological assessment of lumbar spinal stenosis

Background Lumbar spinal stenosis (LSS) is a common and important spinal surgical problem. Currently there is no universally accepted quantitative approach to the radiological measurement of LSS. LSS can be described qualitatively with reference to facet and ligamentous hypertrophy, lack of perineural or intraforaminal fat, and reduced CSF around the cauda equina. Quantitative descriptions do exist e.g., lumbar canal antero-posterior diameter, but these are unidimensional and do not consider normal variation in anatomy. We propose a universal and individualised measurement system for the quantitative radiological assessment of lumbar spinal stenosis. Methods A retrospective case series of patients who had undergone surgery for symptomatic lumbar spinal stenosis over a 3 year period. Pre-operative lumbar spine MRI were analysed. Each patient had the degree of lumbar canal stenosis quantified using our novel approach. Results Our novel formula for the quantitative radiological assessment of lumbar spinal stenosis is two dimensional, repeatable and presented as a percentage, to correct for the individual patient. The surface area of the lumbar spinal canal at the level of stenosis is measured in mm2 plus the adjacent 2 levels which are then averaged. The calculation then becomes (A-S/A) x 100 = R, where S is the canal surface area at the stenosed level in mm2, A is the average canal surface area of the two levels adjacent to the level of interest and R is the relative degree of lumbar spinal canal stenosis expressed as a percentage. Measurements are calculated using axial T2 weighted images. Conclusions This novel quantitative measurement formula for the radiological assessment of lumbar canal spinal stenosis is quick and simple to calculate and most importantly adjusts for the individual patient’s normal or degenerative anatomy. This new measurement tool will need validation against specific clinical and operative criteria in the future.

The effect of different irrigation solutions and activation techniques on the expression of growth factors from dentine of extracted premolar teeth.

To evaluate in a laboratory study, the effect of different canal irrigant solutions and activation techniques on transforming growth factor (TGF-β1), insulin growth factor-1 (IGF-1), bone morphogenetic protein-7 (BMP-7) and vascular endothelial growth factor-A (VEGF-A) release levels from the dentine of extracted premolar teeth. Seventy premolar teeth with single root and canal were used. The lengths of the root segments were standardized to 12mm, and the root canals were prepared up to size 100 with hand files. All surfaces of the teeth were covered with nail polish except the inner root canal surface. The root canals were irrigated with 1.5% NaOCl. Ten teeth were allocated to the control group. The remaining sixty teeth were divided into 2main groups according to the chelating agent used (17% EDTA, 10% Citric acid; CA) and 3subgroups (n=10) according to irrigation activation technique (conventional syringe irrigation (CSI), passive ultrasonic irrigation (PUI) and Er:YAG laser activation). After the activation procedure, the root segments were placed into eppendorf tubes containing 1mL of phosphate-buffered saline solution and kept at 37℃. TGF-β1, IGF-1, BMP-7 and VEGF-A release levels from dentine were measured using the enzyme-linked immunosorbent assay (ELISA) method at 24 h and at day 7. The volume of root canals was calculated using cone-beam computed tomography. The growth factor levels were calculated in ng/mL except VEGF-A (pg/ml). Normality analysis of the data was evaluated with the Kolmogorov-Smirnov test. Statistical analysis was performed using the Mann-Whitney-U and Wilcoxon tests. Regardless of the activation type and sampling time, EDTA caused significantly more IGF release than did CA, whereas EDTA and CA were equally effective for the release of the other growth factors. For either EDTA or CA, the lowest and highest growth factor release levels were observed in the CSI and Er:YAG laser groups, respectively (p<.05). All of the growth factors were released significantly more at 24 h than on day 7 (p<.05). Irrigation activation techniques with EDTA or CA increased the release levels of all growth factors from the dentine of canal walls in extracted premolar teeth.

EXPERIMENTAL STUDY OF FURCATION AREA AND PROSPECTS OF ITS COMPLEX TREATMENT

Relevance. The issue of quality endodontic treatment of teeth with complicated caries is still known as requiring thoughtful research. A significant percentage of periodontitis occurs in the area of furcations of multi-rooted teeth, sometimes alone, but more often as combined with apical periodontitis. Among the number of unsolved tasks, there is question about furcation areas and in particularly their antiseptic treatment and obturation in the complex treatment of chronic apical periodontitis of multi-rooted teeth.&#x0D; Aim: to investigate the histo-morphological features of the furcation area of the first, second molars of the upper and lower jaws and, according to the results of the experimental study, to develop a scheme of complex treatment of chronic apical periodontitis of multi-rooted teeth.&#x0D; Materials and methods. Ten first and second molars of both jaws not affected by fluorosis and removed according to orthodontic or surgical indications in patients aged from 25 to 50 years, were used for this study. In the first stage, transverse and longitudinal sections of the molars were made using diamond-coated separation disks. Using an orthopaedic tip, the first half of the molars were cut longitudinally in the mesio-distal direction with separation disks, under water cooling. The other half of the molars were cut transversely along the neck of the tooth and histochemically stained. In the second stage of the study, we used the experimental application of photodynamic therapy for antiseptic treatment of furcation channels and sealing them with citrate buffer. For this purpose, the next two first and two second mandibular molars were selected, respectively dissected in two planes. Samples were fixed in a vertical position; cotton rolls soaked with 2% methylene blue were placed onto the bottom of each half for 30 s., 1 min., 5 min., and 24 h. In this study we used light binocular stereoscopic microscope MBS-9; histochemical dyes: CHIC-thionine, ammonia silver solution "Argentat", reducing agent (hydroquinone), methylene blue, device "UFL - 122" company "Lux Dent", citrate buffer solution and white clay. The results were recorded with a digital camera mounted on a microscope tube.&#x0D; Results and discussion. The results of histochemical examination of ten molars showed the presence of furcation channels in four teeth. Two samples were stained with CHIC-thionine, the others were stained with two-component "Argenate". The selected samples were dissected in the sagittal plane through the area of localization of the furcation channels and studied under the microscope (magnification: 8x32). In teeth dissected in the transverse plane, the crown and mouth pulp were instrumentally removed without dilation of the root canals and stained accordingly.&#x0D; Thus, when modelling the stage of photodynamic treatment using a 2% solution of methylene blue, there is a significant filling of furcation channels and root canals along their entire length. The photosensitizer 2% methylene blue at the exposure of 30s demonstrates the highest efficiency at the minimum staining of surrounding fabrics. The microscopy was performed to confirm the ability of the photosensitizer to penetrate into the furcation channels at х8 – х32 magnification.&#x0D; After the experimental filling of furcation channels and root canals, we can see clear white stripes along their entire length on the dentin surface of the longitudinal section of the root; these stripes are obliquely directed towards the canal surface and consist of numerous dentinal tubules impregnated with citrate buffer. Numerous thin white lines are clearly visible on the surface of the section that run in parallel, tangentially through almost the entire thickness of the root wall and end up their course in the area around the peripulpal dentin. This indicates the formation of calcium citrate in the root canal that tightly covers its entire surface impregnating the dentinal tubules and completely fills them along their entire length.&#x0D; Therefore, the experimental model of using 2% methylene blue photosensitizer at a 30 s. exposure for photodynamic therapy and citrate buffer for obturating furcation and root canals can be applied in the treatment of patients with chronic apical periodontitis and lesions of the furcation area.&#x0D; Conclusions. Thus, morphological studies of the first and second molars of both jaws have shown the presence of furcation channels, which anatomical structure is quite complex and demanding in terms of their antiseptic treatment and filling. Therefore, we developed new effective for disinfection and obturation techniques including applying photodynamic therapy for disinfection of furcation channels and citrate buffer for their obturation.

Micro-CT evaluation of rotary and reciprocating glide path and shaping systems outcomes in maxillary molar curved canals

The shaping outcomes after instrumentation with rotary and reciprocating glide path and shaping systems were evaluated through micro-computed tomography (Micro-CT). Thirty extracted maxillary first molars were selected. Mesio-buccal canals were randomized into two groups (n = 15): rotary system ProGlider and ProTaper Next X1, X2 (PG-PTN) and reciprocating system WaveOne Gold Glider and WaveOne Gold Primary (WOGG-WOG). Specimens were micro-CT scanned before, after glide path and after shaping. Increase in canal volume and surface area, percentage of removed dentin from the inner curvature, centroid shift and canal geometry variation through ratio of diameter ratios (RDR) and ratio of cross-sectional areas (RA) were measured in the apical and coronal levels and at the point of maximum curvature. The number of pecking motions needed to reach the working length (WL) was recorded. One-way ANOVA and post hoc Turkey–Kramer tests were used (p < 0.05). Post-glide path analysis revealed that in the coronal third, RDR was more favorable to PG and centroid shift was lower for WOGG in the apical third. Post-shaping analysis showed a reduced removal of dentin and a more favorable RA for PTN at point of maximum curvature. The number of pecking motions up to WL resulted in different between groups both for glide path and shaping phases. Despite a higher dentin removal for reciprocating instruments at the point of maximum curvature, both systems seemed to produce well-centered glide path and shaping outcomes. Rotary and reciprocating systems seemed able to respect the original canal anatomy.

Shaping efficiency of XP-endo shaper and Mtwo instruments in long oval root canals: A micro-CT study.

This study evaluated the shaping ability of XP-endo Shaper and Mtwo systems in long-oval-shaped canals of extracted human mandibular molars using micro-computed tomography (micro-CT). Images recorded before and after preparation were evaluated for morphometric measures regarding increase in canal volume, dentin removed, surface area, untouched walls and structure model index (SMI). Data were statistically analysed using the Mann-Whitney test with 5% of significance. On both groups, the root canal preparation significantly increased all analysed parameters (P > 0.05). There was no statistical difference between XP-endo Shaper and Mtwo systems in the increase of the canal volume (30.50%-27.82%), in volume of dentin removed (2.77%-2.40%), in the increase of the canal surface area (11.30%-8.86%), in canal untouched surfaces (9.57%-8.51%) and in the SMI (2.59%-2.68%), respectively. XP-endo Shaper and Mtwo systems showed similar shaping efficiency and were not able to completely prepare the walls of long-oval-shaped canals of extracted human mandibular molars.

Canal surfaces with generalized 1-type Gauss map

This work considers a kind of classification of canal surfaces in terms of their Gauss map G in Euclidean 3-space. We introduce the notion of generalized 1-type Gauss map for a submanifold that satisfies...

Comparison of Anti-Bacterial Efficacy between Passive Ultrasonic Irrigation and 980 nm-GaAlAs Laser Application in Two Root Types.

Background and Objectives: The purpose of the present study was to investigate the anti-bacterial efficacy of passive ultrasonic irrigation (PUI) and a 980-nm-gallium-aluminum-arsenide (GaAlAs) laser using a real-time DNA-based quantitative polymerase chain reaction (qPCR) assay and scanning electron microscopy (SEM). Materials and Methods: Eighty-six extracted single- and double-rooted human teeth were used in the experiment. The following four experimental groups were evaluated, as well as a control group: group 1: single root + PUI (n = 20); group 2: single root + laser application (n = 20); group 3: double roots + PUI (n = 20); group 4: double roots + laser application (n =20); control group (n = 6): 3 single roots, 3 double roots. The qPCR assay was performed in three stages to evaluate the efficacy of the adjunctive method against Enterococcus faecalis. SEM analysis was also used to examine the microstructure of root canal surfaces. The data were statistically analyzed using the Friedman test and the Kruskal–Wallis test with Bonferroni adjustment. Results: The decrease in the DNA levels from S1 (before preparation) to S2 (just after preparation) was highly significant in all groups, and decreases in DNA levels from S2 to S3 (after incubation for 1 week) were found in all experimental groups except group 1. An inter-group analysis showed that PUI was significantly more effective in terms of antibacterial efficacy than GaAlAs laser irradiation in single root (p < 0.05). However, in double roots, experimental groups did not show significantly lower DNA levels than the control group (p > 0.05). SEM images showed that cleaning of the root canal surface and reduction of dentin debris were achieved only in single-rooted teeth when using PUI application. Conclusions: Two adjunctive methods were effective in reducing E. faecalis in single rooted tooth.

Design, metallurgical features, mechanical performance and canal preparation of six reciprocating instruments.

To compare six reciprocating instruments regarding their geometric design, metallurgical characteristics, mechanical behaviour and ability to prepare root canals. A total of 246 new 25-mm NiTi instruments (41 per group) from six reciprocating systems (Reciproc, Reciproc Blue, One Files, One Files Blue, Reverso Silver, and WaveOne Gold) were evaluated throughout a multimethod approach regarding their design using stereomicroscopy (number of blades and helix angle) and scanning electron microscopy (blades symmetry, cross section and surface finishing), nickel-titanium composition, phase transformation temperatures, mechanical performance (cyclic fatigue, torsional and bending resistance) and unprepared canal surface area on anatomically matched mandibular molars assessed by micro-CT. One-way ANOVA and post hoc Tukey's or Mood's median tests were selected depending on sample distribution with significance level set at 5%. The instruments had similarities regarding their metal composition and unprepared canal area, whilst differences in phase transformation temperatures and geometric design (number of blades, surface finishing and tip geometry) were observed. Overall, no difference was observed regarding the maximum torque values (P>0.05), whilst One Files (72s) and One Files Blue (414s) had the shortest and longest times to fracture, respectively (P<0.05). Similar angles of rotation were observed in Reciproc (310°), One Files (285°) and Reverso Silver (318°) instruments (P>0.05), which were significantly lower than Reciproc Blue (492°), One Files Blue (456°) and WaveOne Gold (492°; P<0.05). Maximum bending load demonstrated that Reciproc Blue (201.3 gf) was significantly more flexible that the other instruments (P<0.05). Although there were similarities in metal composition and percentage of unprepared canal surface, the instruments had differences in the overall geometric design, phase transformation temperatures and in the four mechanical resistance parameters (time to fracture, maximum torque, angle of rotation and maximum bending load).

Efficacy of EDDY, passive ultrasonic irrigation and manual irrigation on the removal of orange-brown precipitate

Aim: The aim of this study was to compare the different irrigation activation techniques for removing the orange-precipitate formed after irrigation with sodium hypochlorite (NaOCl) and chlorhexidine (CHX).&#x0D; Methodology: In total, 45-single rooted extracted human teeth were prepared with the ProTaper NEXT rotary system. The roots were respectively irrigated with 5% NaOCl and 2% CHX solutions, and an orange-precipitate formed on the canal walls. The teeth were divided longitudinally, and the precipitate was evaluated with a dental operating microscope (DOM) at 16x magnification before the sections were joined. The halves of roots were then combined, and EDDY, passive ultrasonic activation (PUI) and manual irrigation (MI) techniques were applied for 1 min with 5 ml of distilled water to remove the precipitate. The halves were re-evaluated under the DOM and the residual of percentage of precipitate removed was calculated. The data were evaluated statistically by Kruskal-Wallis tests.&#x0D; Results: A residual orange-precipitate was found in all groups. Although the orange precipitate was effectively removed in the EDDY group, there was no statistically significant difference among EDDY, PUI and MI (p&gt; 0.05).&#x0D; Conclusions: None of the techniques used completely removed the orange precipitate from the root canal surfaces. Among the irrigation activation techniques, there was no superior technique for removing the orange-precipitate from the root canals. &#x0D; &#x0D; How to cite this article: İnce Yusufoglu S, Keskin NB. Efficacy of EDDY, passive ultrasonic ırrigation and manual irrigation on the removal of orange-brown precipitate. Int Dent Res 2021;11(1):1-5. https://doi.org/10.5577/intdentres.2021.vol11.no1.1&#x0D; &#x0D; Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.