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Aim: The study was to examine rapid maxillary expansion (RME), semi-rapid maxillary expansion (SRME), and slow maxillary expansion (SME) compare the root resorptions occurring in the supporting upper first premolar teeth during treatment by using micro-computed tomography (micro-CT). Methodology: Thirty individuals that required maxillary expansion and upper first premolar tooth extraction were divided into three groups consisting of 10 individuals for RME, SRME, and SME. RME group, first premolar and first molar teeth with hyrax screw were activated 1/4 tour twice daily with the banded hyrax appliances. SRME group, acrylic bonded hyrax appliances were activated 1/4 tour per every morning and night until the opening of the suture. Upon the opening of the suture, it was activated 1/4 tour per every two days until sufficient maxillary expansion was gained. SEM group, quad helix appliances were activated per every 20 days. After 12 weeks of the retention period, the upper first premolar teeth were extracted. The teeth were scanned with Micro-CT (SkyScan 1172, Kontich, Belgium), and images were analyzed Dell Precision T5500 to determine the resorption crater volumes. Results: In all samples, the resorption craters were concentrated on the buccal surfaces of the tooth roots. The highest resorption craters volume, the total resorption volume, was observed in the RME group, followed by the SRME group, and the least resorption crater volume was detected in the SME group. Conclusion: Since the supporting teeth were exposed to more force on the root surfaces, the most resorption was seen in the RME group. [ABSTRACT FROM AUTHOR]

This study aimed at evaluating volumetrically gaps and voids of calcium-silicate based materials of different generations and handling properties (BC—Endosequence BC RRM-Fast Set Condensable Putty, MTA—ProRoot MTA, and BIO—Biodentine) in simulated furcal perforations in an ex vivo setup by microcomputed tomography (Micro-CT) analysis. Thirty-six extracted human mandibular molars with sound furcation areas were selected. Standardized perforations were created in the furcation area of the pulp chamber using #4 diamond burs. The specimens were randomly assigned to three groups (BC, MTA and BIO; n = 12). Samples were then scanned (SkyScan 1172; Bruker-microCT, Kontich, Belgium), and three-dimensional (3D) images reconstructed. The relative volume of gaps (VG%) and voids (VV%) present on each material was calculated. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey's HSD test (p < 0.05). Mean VG% for BC, MTA, and BIO groups were, respectively, 0.513%, 1.128%, 1.460%, with BC presenting statistically (p < 0.05) fewer gaps formation than the other groups. Mean VV% were, respectively, 0.018%, 0.037%, and 0.065%. The was no statistical difference regarding VV%. There were no gap-free and void-free samples. BC group had the lowest VG% among the groups with a significant statistical difference (p < 0.05). [ABSTRACT FROM AUTHOR]

Bacterial biofilms are related to various dental and periodontal infectious diseases, and the characterization of this biological structure with micro-computed tomography (micro-CT) may offer valuable information for clinical and research applications. In this study, we aimed to develop a model to visualize three-dimensionally the biofilm structure on dentin using micro-CT. Dentin blocks were prepared and incubated in tryptic soy broth with Enterococcus faecalis (ATCC 29212). The control group did not receive any staining procedure, while groups 1 and 2 were stained with 100% and 50% barium sulfate, respectively. Transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM) were used to detect biofilm formation, barium sulfate penetration, and microbial cell density in the biofilm. Micro-computed tomography (micro-CT) (SkyScan 1172, Bruker Co., Belgium) was used to visualize biofilm formation on the dentin blocks. Biofilm thicknesses were measured from 10 different locations on the specimen surfaces, using CTAn v.1.14.4 software. Obtained data were statistically analyzed using Kruskal–Wallis and Dunn's tests. TEM photomicrographs showed that barium sulfate could penetrate the biofilm structure. CLSM analysis showed that viable and total cell densities were similar between the control and barium sulfate-treated groups (P > 0.05), indicating barium sulfate had no significant influence on cell density. In barium sulfate-treated blocks, biofilm could be discriminated from the dentin, and its thickness could be measured with micro-CT. This study showed that bacterial biofilm on dentin could be characterized by micro-CT after barium sulfate staining without causing any significant side effect on viable and total cell densities. [ABSTRACT FROM AUTHOR]

The 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. Twenty-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. A 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). The 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. [ABSTRACT FROM AUTHOR]

We performed a micro–computed tomographic assessment of the preparation of moderately single- and double-curved root canals using 3 single-file reciprocating nickel-titanium systems: S1 Plus Standard (Sendoline, Täby, Sweden), WaveOne Gold Primary (Dentsply Sirona, Ballaigues, Switzerland), and Reciproc R25 (VDW, Munich, Germany). Seventy-five moderately curved mandibular molars with 2 separate mesial root canals were assigned to 3 experimental groups (n = 25) (ie, S1 Plus Standard, WaveOne Gold Primary, and Reciproc 25 groups) by forming matched triples according to curvature (15°–40°), radius (≤18 mm), and type of curvature (single or double curved). Teeth were scanned before and after root canal preparation with a resolution of 10.5 μm using micro–computed tomographic imaging (Bruker SkyScan 1272; Bruker microCT, Kontich, Belgium). The following parameters were assessed: changes in root canal volume and surface area, percentage of unshaped canal walls, structure model index, canal transportation, and centering ratio. Data were analyzed using 2- and 3-way analysis of variance with Tukey and Scheffé post hoc tests (significance level of 5%). No significant differences among groups were observed concerning all parameters. The type of curvature had no significant effect on all tested parameters. Within all experimental groups, canal transportation increased significantly from the apical to the coronal region, of which the majority was directed toward the furcational area. Preparation with the 3 nickel-titanium systems did not result in significantly different dimensional changes, and there was no significant effect of the type of curvature on all tested parameters. [ABSTRACT FROM AUTHOR]