Increase In Canal Volume Research Articles

Evaluation of Minimally Invasive Preparation of Curved Mesial Canals of Mandibular Molars – An In Vitro Study

IntroductionCurved mesial roots can be challenging for different stages of endodontic treatment. Preparation aims to enlarge, clean, and shape the root canal system, and hundreds of systems are available to carry it out. Aiming to maintain pericervical dentin, minimally invasive preparation was proposed, and with it, instruments with lower tapers emerged. This study aimed to evaluate the increase in canal volume, the centering ability of the instruments, and root canal transportation of two different rotary systems with lower tapers. MethodsEighteen curved mesial roots of extracted mandibular molars were scanned by micro-CT at 3 moments: initial and after the 2 stages of endodontic preparation. The canals were prepared using TruNatomy (TN) and ProDesign Logic 2 (PDL2) instruments up to sizes 25.04 and 26.04, respectively, and after 36.03 and 35.05, respectively. The data were analyzed using parametric and nonparametric tests with a significance level of 5%. ResultsTN and PDL2 systems showed no difference regarding the increase in the volume of the canals with the first instruments, but after preparation with a diameter size of 35 or 36, there was a difference (P < .01) between the systems in the cervical and middle thirds. ConclusionBoth systems shaped the mesial canals of mandibular molars while keeping low transportation and good centering ability in enlargements up to diameter size 35 or 36 with tapers of 3 or 5%.

Shaping ability of three instrumentation system in moderately curved canals: A micro-CT study.

This study aims to compare the shaping ability of three systems using micro-computed tomography (micro-CT). Moderately-curved mesial canals of 36 mandibular molars were assigned to three groups (n = 24); Protaper Next (PTN, 0.25, 0.06), WaveOne Gold (WOG, 0.25, 0.07), TruNatomy (TRN, 0.25, 0.04), and instrumentation was performed. Pre- and post-micro-CT scans were obtained. Canal volume and surface, structure model index (SMI), centroid shift, canal transportation, and untouched canal were analyzed. One-way ANOVA and Student's t-test were used for statistics. There was no difference in SMI, centroid shift, and centering ability between the study groups (p > .05). Removed dentin and canal surface changes were lower in TRN, while untouched dentin walls were higher (p < .05). Cross-sections became more rounded (p < .05), but not significant between groups (p > .05). Considering the removed dentin by TRN, it can be used in critical dentin thickness, such as the danger zone (DZ). PTN, WOG, and WOG kept the original canal course similarly. Untouched dentin by TRN (41%) was wider than PTN and WOG, consequently, meticulous irrigation is recommended. TRN, which provides a controlled increase in canal volume, can be used in thin dentin such as the DZ, however, its use should be supported by copious irrigation and brushing considering the rate of untouched dentin walls. RESEARCH HIGHLIGHTS: TRN presented a higher untouched dentin wall compared to PTN and WOG. Canal volume and surface changes were the lowest in the TRN group. The centering abilities were similar in PTN, WOG, and TRN.

A Three-Dimensional Morphological Assessment for Evaluating Pre- and Postsurgery in Cervical Laminoplasty

ObjectiveThe efficacy of medical treatments and the changes in radiological imaging before and after treatment have consistently remained pivotal factors. This is particularly critical for surgical procedures, where precise evaluation of disparities pre- and post-surgery or the accuracy of implantation is paramount. Based on three-dimensional morphological interests, we provide an automatic quantification evaluation method that delivers an evident base for assessing the outcomes of a widely employed surgical technique, cervical laminoplasty. MethodsThe sample study included patients who underwent cervical laminoplasty for cervical spondylotic myelopathy/ossification of the longitudinal ligament. We present a superimposition method that facilitates a unique and precise assessment between pre and post-surgery. The degree of expansion was evaluated by the canal volume increase and canal expansion rate after surgery. ResultsThere were 31 patients with 112 vertebral segments measured. The target cervical's pre- and post-operative canal areas were 122.63 ± 30.34 and 196.50 ± 37.10 mm2, respectively (P < 0.001). The average cervical canal expansion rate was 64.42%. The expansion effect of C5 cervical laminoplasty was the maximum (71.01%), and the canal volume of other segments expanded by approximately 60%. The functional outcomes demonstrated significant improvements in symptoms. ConclusionsThe quantification evaluation method can be utilized for any morphology changes before and after laminoplasty, as it does not lead to errors or variations from different inspection machines or human factors. The automatic method delivers an evident base for assessing the outcomes of a widely employed surgical technique.

Root Canal Preparation of a Commercial Artificial Tooth versus Natural Tooth—A MicroCT Study

This study aimed to evaluate by microCT the preparation of the artificial teeth (ATs), TrueTooth®, versus natural teeth (NTs): (1) the time and number of pecking movements needed for preparation; (2) the root canal volume increase; (3) if the pulp-colored medium has any effect on the 3D analysis. Material and Methods: Artificial and natural maxillary molars were used. Fourteen AT distobuccal canals and fourteen NT buccal canals were used for the first and second aim and fourteen AT mesiobuccal canals for the third aim. Results: No statistically significant differences were observed regarding the time and number of pecking movements (p &gt; 0.05); for the root canal volume increase, a statistically significant difference was observed (p &lt; 0.05) with a higher mean value for NTs; however, in the group of ATs, there was a volume decrease in three cases. The AT mesiobuccal root canal mean volume increase was also negative. Conclusions: There are no differences between the time and number of pecking movements between NTs and ATs, so TrueTooth® can potentially be used in endodontic training. The volume increase between ATs and NTs was higher in NTs. However, some samples showed negative values, also seen in the AT mesiobuccal canal, confirming that the pulp-colored medium has an effect on the 3D analysis.

Shaping ability of WaveOne Gold and OneReci by using two apical sizes: a micro-computed tomographic assessment.

OneReci (MicroMega, Besançon, France) is a recently introduced single-file reciprocating system with scarce information revealed on its shaping ability. This study aimed to compare the shaping abilities of OneReci and a well-documented single-file reciprocating system WaveOne Gold (WOG; Dentsply Maillefer, Ballaigues, Switzerland) and evaluate the effect of increased apical enlargement on the preparation quality, using micro-computed tomography (micro-CT). After an initial micro-CT scanning, twenty mesial root canals of mandibular molars were anatomically matched. The canals were assigned to two experimental groups (n=10), using OneReci or WOG in different canals of the same root. The glide paths were created, and root canals were prepared twice, using size 25 and 35 instruments of the systems, respectively. The specimens were scanned with micro-CT after each preparation. The increase in canal volume, amount of dentin removal, unprepared root canal surface, canal transportation, centering ratio and preparation times were assessed. The data were analysed with independent sample t-tests, variance analyses, Friedman and Mann-Whitney U tests. The significance level was set at 5%. Each preparation increased the canal volume and dentin removal while decreasing the unprepared root surface. The difference between the systems became significant after preparation with size 35 instruments (p<0.05). Regarding canal transportation and centering ratio, the difference was insignificant (p>0.05). The first preparation step (glide path + size 25 instrument) was significantly faster in the OneReci group (p<0.05). Preparation with size 25 instruments of the systems appeared to be safe with similar shaping performances. Larger apical preparation promoted significantly higher dentin removal, volume increase, and prepared surface area in WOG.

Influence of brushing motions on the shaping of oval canals by rotary and reciprocating instruments.

The effects of brushing on shaping with three different instruments were assessed in oval canals. Mandibular incisors were assigned to 6 groups (n = 12/group) according to the system, each one with or without brushing: Reciproc Blue, VDW.Rotate, and Race EVO. Micro-computed tomography was performed before and after preparation. Brushing strokes caused no increase in canal volume, surface area, and structure model index independently of the system (p > 0.05), except for RaCe EVO in the full canal surface area (p < 0.05). Brushing did not increase the prepared areas (p > 0.05), except for Reciproc in the apical canal (p < 0.05). Reciproc with no brushing exhibited less pericervical dentin than with brushing (p < 0.05), while RaCe EVO with brushing resulted in less remaining dentin (p < 0.05). The brushing motion had no effects on the overall shaping performance of the 3 instruments tested. An exception was the increase in prepared surface area in the apical canal segment when the Reciproc instrument was used with brushing strokes.

Evaluation of Dentine Structure Loss after Separated File Retrieval by Three Different Techniques: An Ex-vivo Study.

To evaluate the success rate of retrieving separated instrument, the root canal volume changes using cone-beam computed tomography and the retrieval time using Ruddle's technique, Terauchi file retrieval kit (TFRK) and Endo Rescue kit. Sixty human mandibular first molars were selected, and a 4-mm portion of #25/.04 rotary files were separated in the middle third of moderately curved mesio-buccal canals. Teeth were randomly assigned into three groups (n=20): R group, in which separated files were retrieved according to Ruddle's technique; T group, in which separated files were retrieved using TFRK and E group, in which separated files were retrieved using Endo Rescue kit. Values were analyzed using IBM SPSS. Results presented as mean+-standard deviation and 95% confidence interval for the root canal volume and time and frequency (%) for success rate. Comparisons of differences in time, canal volume and success rate between groups were assessed. Retrieval was successful in R and T groups (70% and 80% respectively) without any significant difference between them (p=0.715), while E group hadn't any successful samples (0.0%) with significant difference compared to R and T groups (p<0.001, p<0.001). E group showed the highest increase in canal volume followed by R group, while T group exhibited the lowest increase in canal volume. There was no significant difference in the mean retrieval time between R and T groups (p=0.815). TFRK provides a more conservative way for retrieval of separated instrument from the middle third of moderately curved canals. (EEJ-2023-01-01).

Microtomographic Assessment of the Shaping Ability of the Hyflex CM and XP-endo Shaper Systems in Curved Root Canals.

This study compared the shaping ability of the Hyflex CM and XP-endo Shaper rotary file systems in curved mesial canals of mandibular molars using micro-computed tomography. Seventeen mesial roots of extracted first mandibular molars with two independent mesial canals were scanned before and after root canal preparation with the tested rotatory file systems. Each mesial canal from the same specimen was prepared with one of the two systems. The parameters analyzed were canal centering (transportation) for the cervical, middle, and apical segments, as well as for the entire canal (0-10 mm from the apex); and canal volume increase, canal surface area increase, and unprepared canal walls for two segments, 0 to 4 mm and 0 to 10 mm from the apex. There was no significant difference between both systems regarding canal centering (transportation), volume increase, and unprepared canal walls for the 0 to 10 mm segment (p> 0.05); however, a significant difference was observed for the 0 to 4 mm segment (p <0.01), where the Hyflex CM left 28.46% of unprepared walls and XP-endo Shaper left 13.26%. The shaping ability of the two tested rotatory file systems in mesial roots of first mandibular molars was similar for all parameters in all the segments evaluated, except for the 0 to 4 mm segment, where XP-endo Shaper left a smaller area of unprepared canal walls than Hyflex CM.

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.

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.

Three-dimensional analysis of the root canal preparation with Reciproc Blue\xae, WaveOne Gold\xae and XP EndoShaper\xae: a new method in vivo

BackgroundThe purpose of this study was to evaluate the changes in canal volume after root canal preparation in vivo with 3 different single-file techniques (Reciproc-Blue®, WaveOne-Gold® and XP-EndoShaper®), with a new method using CBCT and 3D reconstruction.MethodsIn this prospective study, thirty human lower premolars from healthy patients were used, in which extraction was indicated for orthodontic reasons. All the teeth used were caries- and restoration-free with complete root development, without signs of periodontal disease or traumatic occlusion, and with only one straight canal (up to 25º curvature). Teeth were randomly divided into three different groups: Reciproc-Blue, WaveOne-Gold and XP-EndoShaper. CBCT scans before root canal preparation were used to create a 3D reconstruction with RHINOCEROS 5.0 software to assess the initial canal volume, and then compared with 3D reconstructions after canal preparation to measure the increase in canal volume. Student’s t test for paired data were used to determine statistically significant differences between the before and after canal volumes. Anova test was used to determine statistically significant differences in the percentage of canal volume increase between the groups and Tukey's post-hoc test were used to paired comparison.ResultsReciproc-Blue showed the higher increase in canal volume, followed by WaveOne-Gold and XP-EndoShaper (p = 0.003). XP-EndoShaper did not show a statistically significant increase in canal volume after root canal preparation (p = 0.06).ConclusionWith this model, Reciproc-Blue showed higher increase in root canal volume, followed by WaveOne-Gold, while XP-EndoShaper did not significantly increase root canal volume during preparation.

Effect of Root Canal Preparation on Propagation of Dentinal Microcracks.

This study evaluated the propagation of dentinal microcracks and the root canal volume increase after being prepared with two endodontic instruments: ProTaper Next (PTN) and WaveOne Gold (WOG) by micro-computed tomography analysis. We selected 48 maxillary molars randomly distributed in two groups: PTN and WOG. The samples were scanned before and after instrumentation, and then the image analysis was performed to detect the propagation of pre-existing dentinal micro-cracks and calculate the pre- and post-instrumentation volume. The statistical analysis was performed using Student's t-test, Fisher's exact test, and ANCOVA (P<0.05). Dentinal microcracks were observed in 95.8% of the samples, both PTN and WOG instruments propagated microcracks after instrumentation, but there was no significant difference between the instruments (P=0.538). In relation to the root canal volume there was no statistic difference between PTN and WOG systems for the mesiobuccal (P=0.426) and distobuccal root canals (P=0.523). We can conclude that both ProTaper Next and WOG systems propagate dentinal microcracks after root canal preparation in this in vitro study, without statistical significance. The root canal volume prepared also showed no statistically significant difference between the two groups. This in vitro study requires further studies for more concrete conclusions.

Comparison of Canal Transportation and Centering Ability of ProGlider and WaveOne Gold Glider in Curved Canals

Objectives The aim of this study was to compare the volume variation and maintenance of the root canal position when using the ProGlider 16.02 (PG) and the WaveOne Gold Glider 15.02 (WOGG) file systems for glide path preparation. Materials and Methods Twenty-four moderately curved mesiobuccal canals of maxil-lary first molars were selected and randomly divided into two groups: PG and WOGG. The selected teeth were scanned using microtomography before and after root canal preparation to assess centralization and linear transport at 1, 3, 5, and 7 mm from the apical foramen. Statistical Analysis The data were analyzed with the Mann–Whitney U test. The level of significance was 5%. Results There were no significant differences in volume variation or root canal transport ( p > 0.05). There was a significant difference in the centralization of the root canal at 3 mm from the foramen ( p < 0.05). Conclusions WOGG and PG instruments presented similar results regarding the root canal volume increase and transport. WOGG caused higher decentralization at 3 mm from the apical foramen.

Assessment of Mechanical Root Canal Preparation with Centric Reciprocating or Eccentric Rotary Kinematics: A Micro–computed Tomographic Study

IntroductionThe aim of this study was to compare, using micro–computed tomographic imaging, the preparation of mesial canals of mandibular molars with the Reciproc (VDW GmbH, Munich, Germany) and XP-endo Shaper (FKG, La Chaux-de-Fonds, Switzerland) systems, evaluating changes in dentin and canal volume, the percentage of untouched walls, the volume of accumulated hard tissue debris, and root canal deviation in the apical third. MethodsTwenty-four mandibular molars with 2 mesial root canals and a single foramen were anatomically paired and divided into 2 experimental groups (n = 12) according to the system used. The specimens were scanned before and after preparation with the SkyScan 1176 microtomographic scanner (Bruker-microCT, Kontich, Belgium) at a resolution of 17.42 μm. The resulting data were statistically compared at a significance level of 5% using the Student t test and the Mann-Whitney test. ResultsA significant difference was observed in the untouched surface area for the total canal and the cervical and middle thirds, with the lowest untouched surface area in the XP-endo Shaper group (P < .05). The volume of accumulated hard tissue debris was significantly higher in the Reciproc group in the total canal as well as in the middle and apical thirds. There was no significant difference between the groups regarding the volume of dentin removed or the increase in canal volume and surface area (P > .05). ConclusionsThe XP-endo Shaper touched more walls and left less accumulated hard tissue debris in the root canal system than the Reciproc group. Although the XP-endo Shaper showed superior results, neither system was able to fully prepare the root canal.

Micro-CT evaluation of ProTaper Next and WaveOne Gold shaping in maxillary first molars curved canals: an in vitro study

Introduction: The aim of this micro-CT study was to analyze the geometrical shaping outcomes after instrumentation with rotary and reciprocating glide path and shaping systems. Materials and Methods: The mesio-buccal canals of thirty extracted maxillary first permanent molars were randomized into two groups (n=15): rotary system ProGlider and ProTaper Next X1, X2 (PG-PTN) was compared with reciprocating system WaveOne Gold Glider and WaveOne Gold Primary (WOGGWOG). Irrigation was performed with EDTA 10% and NaOCl 5%. Specimens were micro-CT scanned before instrumentation and after glide path and shaping. The measured parameters were the increase in canal volume and surface area, the centroid shift and the canal geometry variation through RDR and RA. These parameters were measured in the apical and coronal levels and at the point of maximum curvature. One-way ANOVA and post hoc Turkey- Kramer tests were used to describe the impact of the instrumentation on the selected parameters (P<0.05). Results: Post glide path analysis revealed that increase in canal surface area was slightly greater in WOGG group (P=0.051). Centroid shift was not significant even if the trend seemed more favorable to PG group, except for the apical third. Centroid shift reported no significant differences. Conclusions: Both rotary and reciprocating systems seemed to create a homogeneous and well-centered glide path and shaping.

Comparison of glide paths created with K-files, PathFiles, and the ProGlider file, and their effects on subsequent WaveOne preparation in curved canals

BackgroundThe root canal glide path has been recommended as the foundation for a safer root canal preparation. The aim of this study was to compare glide paths created with K-files, PathFiles, and the ProGlider file, and their effects on subsequent WaveOne preparation regarding canal transportation, canal volume increase, apical extruded debris, and working time in curved canals.MethodsSixty mesial canals of extracted human mandibular first molars were randomly assigned to the K-file (KF), PathFile (PF) and ProGlider file (PG) groups for glide path preparation. Then, canals were prepared using WaveOne files. Specimens were scanned (voxel size: 18 μm) three times using micro-computed tomography: pre-glide path, post-glide path, and post-root canal preparation. Canal transportations were measured at 1, 3, and 5 mm levels from the apical foramen, and canal volume increases were also accounted. Apical extruded debris during preparation was collected for measurement. Meanwhile,working time was recorded. Data were analyzed statistically using one-way analysis of variance and Tukey’s post hoc tests (p < 0.05).ResultsAfter glide path preparation, the PG and PF groups showed significantly less canal transportation than the KF group at all levels (P < 0.05), while the PG group exhibited a significantly larger canal volume increase than the PF and KF groups (P < 0.05). After the subsequent canal preparation with WaveOne, the PG and PF groups showed significantly less canal transportation than the KF group at 3 and 5 mm levels, and the PG group showed significantly less canal transportation than the PF group at 5 mm level (P < 0.05). However, statistically similar canal volume increases occurred among the three groups. Additionally, the PG and PF groups produced less apical extruded debris compared to the KF group (P < 0.05). The working time of the PG group was the shortest, while that of the KF group was the longest.ConclusionCompared with the PathFiles and K-files, the ProGlider file combined with the WaveOne file showed reduced canal transportation and working time.

184 Effect of Cervical Deformity Correction on Spinal Cord Volume and Stenosis

Abstract INTRODUCTION There persists a debate on whether simple isolation of points of stenosis is sufficient or whether certain deformities must also be mitigated to restore neurologic concerns in patients with spinal deformity. Despite indications that cervical kyphosis has a significant effect on spinal cord volume, there remains no studies examining pre- and post-operative effect of deformity corrections on spinal cord volume and number of stenotic levels. METHODS Cervical deformity patients with pre-operative and 1-year MRI’s available were assessed for spinal canal volume at each interspace and at each body from C2-C7/T1. Stenotic vertebral levels were measured using Pavlov's method from C2-T1. Changes in spinal cord volume and number of stenotic levels from baseline to 1-year according to decompression technique used (laminectomy, foraminotomy, discectomy, or corpectomy) and type of pre-operative cervical deformity were measured using t-tests, and improvement in radiographic alignment and myelopathy scores using bivariate correlation tests. RESULTS &gt;14 patients were evaluated. 11 received an osteotomy, 8 a decompression procedure, 6 received a posterior-only approach while the remaining received anterior-then-posterior approach. Patients presented with an average canal volume of 272.4 mm2 and 4.6 stenotic levels. At 1-year, average canal volume was 343.8 (29% increase), and average stenotic levels was 2.9. Patients with deformity apices in the cervical spine had less baseline canal volume (cervical apex: 231.6 mm2 vs. lower apex: 303.6 mm2, P = 0.022) as well as more stenotic levels cervical apex: 6.0 vs. lower apex: 3.4, P = 0.049). There was no significant relationship between decompressive techniques and volume (with decompression: ? +75mm2, w/o: ? +64mm2, P = 0.591). CONCLUSION This analysis shows a 29% increase in canal volume and correction of stenosis in cervical deformity patients. Realignment resulted in an increase in canal volume irrespective of decompression procedure. This preliminary analysis highlights a need for further investigation of spinal cord changes in deformity cases.

Preparation of Oval-shaped Canals with TRUShape and Reciproc Systems: A Micro–Computed Tomography Study Using Contralateral Premolars

IntroductionThe purpose of this study was to compare the shaping properties of TRUShape and Reciproc systems during preparation of oval-shaped canals from contralateral teeth by using micro–computed tomography scanning. MethodsThirteen pairs of freshly extracted contralateral mandibular premolars with a single oval-shaped canal were selected and divided into 2 groups according to the root canal instrumentation technique, TRUShape and Reciproc. The final apical size of instrumentation was 40/.06 for both systems. Data were statistically analyzed for the increase in canal volume and surface area and the amount of unprepared areas promoted by the 2 systems. ResultsPreparation with both systems significantly increased the volume and area of the canals (P < .001), with no significant differences between them (P > .05). When the full canal length was evaluated, the amount of uninstrumented areas was significantly larger for Reciproc (30%) than TRUShape (24%) (P < .05). However, analysis restricted to the apical 4-mm segment revealed no statistically significant difference in untouched areas (25% for Reciproc and 20% for TRUShape) (P > .05). ConclusionsBoth instrument systems behaved similarly in promoting the increase of root canal volume and surface area. When the full canal length was evaluated, TRUShape instruments showed less unprepared areas than Reciproc. However, this difference did not occur for the apical part of the root canal. None of the techniques could completely prepare oval-shaped root canals.

Effect of finishing instrumentation using NiTi hand files on volume, surface area and uninstrumented surfaces in C‐shaped root canal systems

To assess the effect of 90°-oscillatory instrumentation with hand files on several morphological parameters (volume, surface area and uninstrumented surface) in C-shaped root canals after instrumentation using a single-file reciprocation system (Reciproc; VDW, Munich, Germany) and a Self-Adjusting File System (SAF; ReDent Nova, Ra'anana, Israel). Twenty mandibular second molars with C-shaped canals and C1 canal configurations were divided into two groups (n=10) and instrumented with Reciproc and SAF instruments. A size 30 NiTi hand K-file attached to a 90°-oscillatory motion handpiece was used as final instrumentation in both groups. The specimens were scanned using micro-computed tomography after all procedures. Volume, surface area increase and uninstrumented root canal surface were analysed using CTAn software (Bruker-microCT, Kontich, Belgium). Also, the uninstrumented root canal surface was calculated for each canal third. All values were compared between groups using the Mann-Whitney test and within groups using the Wilcoxon's signed-rank test. Instrumentation with Reciproc significantly increased canal volume compared with instrumentation with SAF. Additionally, the canal volumes were significantly increased after 90°-oscillatory instrumentation (between and within group comparison; (P<0.05)). Regarding the increase in surface area after all instrumentation protocols, statistical analysis only revealed significant differences in the within groups comparison (P<0.05). Reciproc and SAF instrumentation yielded an uninstrumented root canal surface of 28% and 34%, respectively, which was not significantly different (P>0.05). Final oscillatory instrumentation significantly reduced the uninstrumented root canal surface from 28% to 9% (Reciproc) and from 34% to 15% (SAF; P<0.05). The apical and middle thirds exhibited larger uninstrumented root canal surfaces after the first instrumentation that was significantly reduced after oscillatory instrumentation (P<0.05). The Reciproc and SAF system were associated with similar morphological parameters after instrumentation of mandibular second molars with C-shaped canals except for a higher canal volume increase in the Reciproc group compared to the SAF. Furthermore, the final use of 90°-oscillatory instrumentation using NiTi hand files significantly decreased the uninstrumented canal walls that remained after Reciproc and SAF instrumentation.