Human Teeth Research Articles

Effect of surface treatments and bonding type on elemental composition and bond strength of dentin.

The objective of this study was to explore the effect of different surface treatments and bonding types on elemental composition and bond strength of dentin. Under water cooling, 1.5mm of tooth structure containing just dentin was cut from 39 extracted human molars. Dentin surfaces were untreated (control) or treated by erbium: yttrium aluminum garnet or femtosecond laser (n = 13, each). One sample from each group underwent scanning electron microscopy. Then, dentin surfaces were bonded by Clearfil SE Bond or Clearfil SE Protect (n = 6, each). Energy dispersive X-ray spectroscopy was performed both after surface treatment and bonding application. The dual-polymerized resin cement was applied to dentin surfaces with a special teflon mold (diameter:3mm × height:3mm). After polymerization of the resin cement, shear force was applied at the resin cement-dentin interface. Elemental composition value (weight%) of dentin after surface treatment was analyzed by one-way analysis of variance (ANOVA), and the difference value in pre and post-bonding elemental composition by two-way ANOVA. Paired t-tests were executed to compare the weight% values of each element before and after each bonding application. Bond strength was analyzed by two-way ANOVA. The post-hoc test was Tukey's honest significant difference test. Both laser treatments increased the mineral content of dentin, compared to the controls (P<0.05). Application of bonding agents decreased the mineral content of dentin compared to the surface treated dentin. Bond strength was unaffected by either surface treatment or bonding type (P>0.05). For resin cementation, either surface treatment is suitable. After laser treatment, Clearfil SE Bond is recommended over Clearfil SE Protect.

Influence of the preparation design on the retentive strength of resin-bonded attachments

ObjectivesThe study investigated the influence of retention grooves and material thickness of the retainer wing on the retentive strength of resin-bonded attachments (RBAs).Materials and methodsSixty-four extracted human molars were used. Each tooth received a preparation limited to the enamel for the retainer wings of the RBAs. The specimens were divided into eight groups, each containing eight specimens. The groups varied based on the number of conical retention grooves (0, 1, 2, or 4) and the thickness of the CoCr retainer wings (0.4 mm and 0.8 mm). Before testing the retentive strength of the RBAs, the specimens underwent 37,500 thermal cycles followed by dynamic loading of 1,200,000 cycles on the RBAs’ patrices using a chewing simulator. The debonding test was conducted using a universal testing machine at a crosshead speed of 2 mm/min.ResultsThe mean retentive strength ranged from 326 ± 96 N to 440 ± 77 N. Only a small portion of specimens (10.9%) exhibited adhesive failure, while the remainder demonstrated cohesive failure within the tooth structure. Neither the number of retention grooves, the thickness of the retainer wings, nor the size of the bonding surface significantly affected retentive strength.ConclusionsThe findings suggest that reducing the number of retention grooves and the material thickness does not influence the retentive strength of RBAs.Clinical relevanceThe retention of RBAs appears promising, supporting the clinical application of this treatment modality.

In Vivo and In Vitro Response to a Regenerative Dental Scaffold

As dental pulp contains the stem cells necessary for regeneration, the tooth should hold the intrinsic capacity for self-repair. A triphasic hybrid dental biocomposite (3HB) composed of biocompatible biopolymers to provide strength, antibacterial properties and protein-based cell support could provide a conducive microenvironment for the regeneration of dental structures. 3HB was incorporated into Mineral Trioxide Aggregate (ProRoot MTA) to construct a malleable injectable implant. Human tooth pulp cells (hDPCs) significantly increased proliferation in the presence of 3HB+MTA compared to 3HB or MTA alone. Cell viability decreased with MTA alone but increased with 3HB and 3HB+MTA. 3HB+MTA was implanted into the residual tooth of drilled Wistar rat M2 molars for up to 45 days. Stereological analysis from micro-CT images showed the volume of the tooth remaining. Histologically, regenerative pulpal architecture was seen invading 3HB. A continuous odontoblastic profile lined a deposit of dentin-like material suggesting reparative dentinogenesis. Overall, no infection or encapsulation was seen. Immunohistochemically, odontoblasts were seen along the margins of the wounded tooth undergoing repair. Mesenchymal cells (MSCs) were seen at the base of the drilled tooth and by 21 days had translocated into the implant itself. Cells stimulating remineralization were highly expressed in the tooth undergoing repair. CD146-positive MSCs were seen in the center of the implant, possibly stimulating remineralization. In conclusion, behavior of 3HB+ in vitro and in vivo provided a promising start as 3HB+MTA may serve as a viable regenerative scaffold for pulp regeneration; however, this should be further studied before clinical use can be considered.

Comparison of intraoral and extraoral scanners for volumetric assessment before and after caries removal by the ICDAS score: a quantitative analysis.

Aimed to compare the volumetric calculations (VC) of intra-and-extraoral scanners on carious teeth before/after caries removal. 120 extracted human molars with ICDAS scores of 3, 4, and 5 were included. The teeth were scanned using an extraoral scanner (Ineos-X5, Dentsply Sirona) and three intraoral scanners (IOS) (iTero Element-5D, Align Technology; Primescan, Dentsply Sirona; Trios 4, 3Shape) before-and-after caries removal (CR). Eight Standard Tessellation Language (STL) data of each tooth sample were overlapped in Meshmixer (Autodesk) software for VC. Shapiro-Wilk, Paired Two-Sample T-test, repeated analysis of variance test statistics, and intraclass correlation coefficient (ICC) were used (p < 0.05). In initial VC, a significant difference observed between Ineos-X5 and iTero Element-5D (p < 0.001) and Ineos-X5 and Primescan (p < 0.001), regardless of the ICDAS score. No significant difference observed after CR between Ineos-X5 and iTero Element-5D (p = 0.917), Ineos-X5 and Primescan (p = 0.936), and Ineos-X5 and Trios 4 (p = 0.727) respectively. There was also no difference between the three IOS after CR (p ≥ 0.05), whereas the iTero Element-5D scanner significantly calculated less volume than Primescan and Trios-4 initially (p = 0.003). Maximum ICC was observed between the Ineos-X5 and Primescan in the ICDAS 5 score, before CR (ICC = 1, p < 0.001) and triple comparisons of iTero Element-5D, Primescan, and Trios-4 (ICC = 1, p < 0.001). Carious and irregular surfaces might affect the data collection of IOS. Intra-and-extraoral data may present negligible differences in the volumetric calculation, depending on the caries status and anatomical properties. These differences and factors may be important for future artificial intelligence networks that simulate the aftermath of caries removal. The IOSs tested in the current study can successfully collect data from irregular, deep and shallow cavities after caries removal.

Bleaching Gels and Light-Emitting Diodes: Comparison of Tooth Color Change.

To measure difference in tooth shade and color achieved via two different over-the-counter bleaching agents with and without their associated light-emitting diodes (LEDs). A total of 84 extracted human anterior teeth were randomly divided into seven groups. Gypsum models were made with 6 extracted teeth in an arch form (n = 12; 2 arches/group). Samples were kept hydrated throughout treatment (25°C). Bleaching treatment followed manufacturers' instructions with at least 1-h of rehydration between treatments. Control tooth arches were left untreated. L*a*b* values were measured with a Vita Easyshade (VITA North America, Yorba Linda, CA) three times per tooth using white and black backgrounds. ∆E (CIE 2000) was compared between and within treatment groups over time with ANOVA and post hoc Tukey (a = 0.05). Subgroup testing confirmed the data were normally distributed. Two-way ANOVA showed significant interaction between product (Control, Crest, Snow) and treatment (light only, product only, light and product) on ∆E values for black (p-value < 0.001, F = 15.28) and white (p-value < 0.001, F = 13.62) backgrounds. Post hoc pairwise Tukey tests showed a significant effect of light-and-product treatments in contrast to light- or product-only treatments. Repeated measures ANOVA of between-treatment change (∆E) by product showed significant interaction between time and treatment for Snow products (p < 0.001, F = 10.9) and independent effects of time and treatment for Crest products (Time: p-value < 0.001, Treatment: p-value < 0.01, F = 7.21) on a black background. On white backgrounds, only a significant effect of treatment was reported for both Snow (p-value < 0.01, F = 5.427) and Crest (p-value < 0.001, F = 5.61). Overall, a combination of light and gel produces significantly higher tooth color and shade change over time, with the highest change seen for Snow products. Many patients use over-the-counter tooth bleaching products because they are more cost effective and easier to access than in-office bleaching. However, these products may have adverse effects, such as increased sensitivity with repeated use, in addition to increased consumption of time and money. This project measured tooth shade between treatments which can help determine which product is most effective for at home use.

Is Apical Enlargement with Single Reciprocating Instruments the Key to Success in Endodontic Retreatment?

Modern endodontics has provided significant advancements, particularly in the treatment and retreatment of root canals. However, the complete removal of obturation material during retreatment remains a challenge, especially in the apical third of root canals, where complex anatomy imposes limitations. This study aimed to evaluate the effectiveness of using WaveOne Gold reciprocating instruments of different diameters and kinematics (brushing motion and pecking motion) for removing obturation material from root canals during retreatment, with a particular focus on the apical third. Thirty human maxillary molars with separate roots were selected and divided into four groups. Root canals were prepared and obturated using different WaveOne Gold instruments (Primary and Medium) and then retreated with larger diameter instruments using different kinematics. The removal of obturation material was evaluated through cone beam computed tomography (CBCT). The results were statistically analyzed using ANOVA and logistic regression. Statistical analysis revealed no significant differences between the groups regarding the type of instrument or kinematics applied. Residual obturation material was observed in approximately 60% of the samples, regardless of instrument diameter or kinematics used, indicating that complete removal of obturation material from the apical portion of root canals remains a substantial challenge. The use of larger diameter instruments, such as the WaveOne Gold Medium, and the application of brushing motion kinematics did not prove significantly more effective in removing obturation material compared to smaller diameter instruments. These findings highlight the need to explore new approaches and technologies to optimize obturation material removal, especially in complex anatomical regions like the apical third of root canals.

30-Month performance of a 10-MDP based universal adhesive system under mechanical and biological perspectives

Strategies towards the long-term durability of dentin-adhesive interface is the goal of many investigations. As the universal dentin bonding systems (DBS) represents a promissory category, other approaches seem to be refrained. Besides their chemical capacity to bond to dentin, their ability in terms of suppression of dentin metalloproteinases of matrix at the interface is unclear. This study aimed to evaluate the long-term adhesive performance and gelatinolytic activity effect of a 10-MDP-based universal DBS compared with 2 % chlorhexidine digluconate (CHX) as control to connect the understanding of mechanical and biological mechanisms. For this, bond strength to dentin (μTBS) and in situ zymography (Z) at initial, 6-month, and 30-month aging times were run. 102 sound human molars were randomized according to DBS: Adper Single Bond 2 – (SB - MDP-free control); Adper Single Bond Universal in etch-and-rinse (SUER) and self-etching (SUSE) modes. They were subdivided according to dentin pretreatment: W- water or CHX-2% (30s-passive application). The specimens were restored according to the manufacturer's instructions. For μTBS (n = 12), beams (0.64 mm2) were obtained and tested (500N/0.5 mm/min). For Z (n = 5), 0.1 mm-thick slices were incubated with fluorescein-conjugated gelatin (24h/37 °C) and analyzed by confocal laser scanning microscopy. Data were analyzed by three-way ANOVA and Tukey's test (p < 0.05). At 6-month, CHX effectiveness was observed in some circumstances under both tests. However, 30-month assessments evidenced no difference neither among the groups regardless of DBSs nor pretreatment for all comparisons, despite some peculiarities detected under Z. It is concluded that the 10-MDP universal DBS present limited action over the proteolytic action.

A Novel Nano-Hydroxyapatite Agarose-Based Hydrogel for Biomimetic Remineralization of Demineralized Human Enamel: An in-vitro Study.

This study aims to investigate the biomimetic effect of agarose hydrogel loaded with enamel matrix derivative (EMD-agarose) alone or in combination with nano-hydroxyapatite (n-HA-EMD-agarose) on the remineralization of human demineralized enamel. Extracted human mandibular third molars were sectioned into 54 buccal and lingual halves. Acid-resistant nail varnish was applied to each half, except for two enamel windows. Enamel surface microhardness, energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) analyses were conducted to evaluate enamel surfaces at baseline, following demineralization with 37% phosphoric acid, and after each hydrogel application and remineralization for two, four, and six days. Remineralization was performed using a phosphate solution at 37°C. At day 6 following remineralization, a statistically significant higher mean microhardness was recorded in n-HA-EMD-agarose hydrogel (260.87 ± 3.52) as compared to EMD-agarose hydrogel (244.63 ± 2.76) (p = 0.027). Similarly, n-HA-EMD-agarose hydrogel showed a higher mean calcium (46.31 ± 2.78), phosphorous (24.92 ± 0.826), and fluoride (0.909 ± 0.053) weight percentage compared to EMD-agarose hydrogel calcium (19.64 ± 1.092), phosphorous (19.64 ± 1.092), and fluoride (0.7033 ± 0.0624) weight percentage (p < 0.05). Further, SEM analysis revealed a substantial deposition of n-HA following the application of the n-HA-EMD-agarose hydrogel, whereas the EMD-agarose exhibited a relatively smooth enamel surface with less visible enamel rods due to mineral deposition. The combined n-HA-EMD-agarose hydrogel demonstrated improved surface microhardness of the remineralized enamel and enhanced mineral content deposition, indicating its potential as a biomimetic approach for dental enamel repair.

Anti-cariogenic effect of experimental resin cement containing ursolic acid using dental microcosm biofilm

ObjectiveThis study aimed to assess the anticariogenic effects of resin cement containing varying ursolic acid (UA) concentrations and to determine the optimal UA concentrations in the microcosm biofilm model. Materials and methodsExperimental resin cements with UA concentrations of 0, 0.1, 0.5, 1.0, and 2.0 wt% were prepared. Class I cavities were prepared on 50 extracted human molars and restored with composite inlays and experimental resin cements. Tooth samples were subjected to artificial caries induction for 10 days in a microcosm biofilm model using human saliva as an inoculum, and then mineral changes were evaluated using quantitative light-induced fluorescence (ΔF and ΔQ) and micro-computed tomography (CT). The bacterial composition of the human saliva was analyzed by 16s RNA microbiome profiling. One-way analysis of variance with Tukey and Duncan post-hoc tests was employed for statistical analysis (p < 0.05). ResultsAs the UA concentration increased, resin cement decreased ΔF and ΔQ before and after caries induction but showed a significant difference only in ΔQ at UA concentration ≥ 1.0% (p < 0.05). The gray value analysis result of micro CT also showed a significant difference at UA concentration ≥ 1.0% (p < 0.05). In the human saliva analysis, bacterial composition remained within normal oral microbiota ranges. ConclusionResin cements containing at least 1.0% of UA exhibited an anticariogenic effect on dental microcosm biofilms. Clinical relevanceTo reduce the failure of restorations, it is essential to prevent the occurrence of secondary caries. The application of UA in resin cement can be utilized to prevent the formation of secondary caries due to the anticariogenic effect of UA.

Effect of a novel irrigation regimen and root canal filling material versus conventional endodontic protocols on dentin wettability.

The purpose of this study was to compare the effect of different irrigation regimens on the dentin wettability of root canal sealers. The occlusal surfaces of human molar teeth (N = 90) were removed, polished, and divided into three groups (n = 30) based on the irrigation regimen: control group (SAL), standard irrigation group (NES), and test group (ODC). Each group was randomly divided into three subgroups according to the root canal sealer: AH Plus (AHP), Total Fill BC Sealer HiFlow (TOT), and OdneFill (ODF). The contact angle was determined using the sessile drop technique. The pendant droplet method assessed the work of adhesion. Surface roughness was measured using atomic force microscopy. Data were analyzed using non-parametric tests (p < .05). ODC-ODF showed significantly lower contact angle (34.80°) than ODC-AHP (66.53°, p < .001) and ODC-TOT (85.72°, p < .001). In NES, no significant difference was found between ODF and AHP (p > .05) while both groups presented significantly lower results than TOT (p < .001, p < .001, respectively). In SAL, the difference between TOT (92.84°) and AHP (83.24°) was insignificant (p > .05), whereas ODF presented significantly lower results compared to both (p < .001, p < .001, respectively). Surface roughness was lowest in ODC (31.54nm), followed by SAL (62.30nm) and NES (72.02 nms) which was significantly (p = 0.006) higher than ODC, whereas the difference between SAL and NES was insignificant (p > .05). This study highlights the wettability of a new root canal sealer and the effect of a new irrigation activation system on the wettability of different root canal sealers. OdneFill showed superior wettability compared to other sealers while exhibiting a synergistic effect with OdneClean.

In vitro study of the treatment of dentin hypersensitivity with gallic acid combined with sodium fluoride

BackgroundDentin hypersensitivity (DH) is a common oral condition that is associated with severe dental pain. Pain relief is a key focus of the treatment of DH. The purpose of this study was to evaluate the blocking and antacid effects of gallic acid (GA) combined with sodium fluoride (NaF) on dentinal tubules in vitro.MethodsNinety dentin discs from human third molars were treated with 6% citric acid for 2 min. Then, the surface morphologies of ten dentin discs were observed by scanning electron microscopy (SEM). The remaining samples were randomly divided into four groups: the NaF group, which was treated with 1000 ppm NaF; the GA group, which was treated with 4000 ppm GA; the GA + NaF group, which was treated with 1000 ppm NaF + 4000 ppm GA; and the blank group, which was treated with deionized water. The dentin permeability of each sample was measured with a water-filled system before processing and after 7 days of treatment. Dentin morphology and surface deposits were observed by SEM. Then, samples from the NaF, GA + NaF and blank groups were subjected to an acid challenge by incubation with 0.02% citric acid for 2 min. SEM and a water-filled system were used to evaluate the blocking and antacid effects of NaF and GA + NaF.Results1. NaF and GA + NaF significantly decreased dentin permeability. The effect of the GA + NaF treatment was more significant. After acid challenge, both groups still exhibited decreased dentin permeability compared with the initial assessment. 2. Compared with the NaF group, the GA + NaF group had more mineral deposits on the dentin surface and dentin tubules. After acid challenge, the deposits in the GA + NaF group were still clearly visible.ConclusionThe combined effect of GA and NaF on reducing dentin permeability by blocking open dentin tubules is better than that of NaF alone. After acid challenge, the GA + NaF treatment still had a better effect.

DA-Net: A classification-guided network for dental anomaly detection from dental and maxillofacial images

Dental abnormalities (DA) are frequent signs of disorders of the mouth that cause discomfort, infection, and loss of teeth. Early and reasonably priced treatment may be possible if defective teeth in the oral cavity are automatically detected. Several research works have endeavored to create a potent deep learning model capable of identifying DA from pictures. However, because of the following problems, aberrant teeth from the oral cavity are difficult to detect: 1) Normal teeth and crowded dentition frequently overlap; 2) The lesion area on the tooth surface is tiny. This paper proposes a professional dental anomaly detection network (DA-Net) to address such issues. First, a multi-scale dense connection module (MSDC) is designed to distinguish crowded teeth from normal teeth by learning multi-scale spatial information of dentition. Then, a pixel differential convolution (PDC) module is designed to perform pathological tooth recognition by extracting small lesion features. Finally, a multi-stage convolutional attention module (MSCA) is developed to integrate spatial information and channel information to obtain abnormal teeth in small areas. Experiments on benchmarks show that DA-Net performs well in dental anomaly detection and can further assist doctors in making treatment plans. Specifically, the DA-Net method performs best on multiple detection evaluation metrics: IoU, PRE, REC, and mAP. In terms of REC and mAP indicators, the proposed DA-Net method is 1.1% and 1.3% higher than the second-ranked YOLOv7 method.

Accuracy of intraoral versus desktop scanners used in digitizing polyvinyl siloxane impression for fabricating a CAD-CAM customized post and core.

This in vitro study aimed to compare the 3-dimensional (3D) accuracy of intraoral and desktop scanners when digitizing the post and core polyvinyl siloxane impressions. Ten extracted human teeth were prepared to build a post space in the root canal. Each tooth was scanned using a micro-computed tomography device (MCT), and the slice data were reconstructed as controls. A conventional quadrant polyvinyl siloxane impression was made and scanned thrice using an intraoral scanner (IOS) and a desktop blue-light scanner (IMS), with one of the scans randomly selected as the definitive cast. Precision was assessed by comparing the deviations among repeated scans. Trueness was evaluated by analyzing the deviations between the MCT and each definitive cast (MCT-IOS and MCT-IMS). The clinically acceptable root mean square (RMS) value was set to 50 µm. The mean RMS values of the repeated scans of IOS and IMS were 18.3 ± 3.9 µm and 13.9 ± 6.2 µm (P < 0.05), and the difference between them was 4.4 ± 5.9 µm. The mean RMS values of MCT-IOS and MCT-IMS were 28.3 ±3.0 µm and 31.3 ± 4.2 µm (P < 0.05), with a difference of 3.0 ± 2.9 µm. The RMS values were significantly lower than 50 µm (P < 0.05). The IOS showed slightly better trueness than the IMS but slightly lower precision. The precision and trueness of the two scanners for digitizing post and core impressions were acceptable for clinical application.

Coronal Cementum and Reduced Enamel Epithelium on Occlusal Surface of Impacted Wisdom Tooth in a Human

Background: There is only limited research on the coronal cementum of a tooth, and the mechanisms of its forming process are not well-defined. This report presents a coronal cementum on the occlusal surfaces of enamel in an impacted wisdom tooth in a human, which is not nearly the cervical portion. Materials and Methods: The tooth (Tooth #1) was derived from a 46-year-old female. Histological analysis, including hematoxylin and eosin (HE) and toluidine blue (TB) staining, and Scanning Electron Microscopy and Energy Dispersive X-ray Spectrometer (SEM-EDS) analysis of the extracted tooth were conducted. Radiographic examination showed that Tooth #1 was horizontally impacted in the maxilla and had the apex of a single root placed between the buccal and palatal roots of Tooth #2. Results: Coronal cementum was distributed widely on the enamel, and reduced enamel epithelium was also found with enamel matrix proteins histologically. The formation of acellular cementum was observed to be more predominant than that of the cellular cementum in Tooth #1. SEM showed that the occlusal cementum connected directly with enamel. Calcium mapping revealed an almost similar occlusal cementum and enamel. In addition, the spectrum of elements in coronal cementum resembled the primary cementum according to SEM-EDS. Discussion: Thus, coronal cementogenesis in impacted human teeth might be related to the existence of reduced enamel epithelium.

The impact of the filling technique with two sealers in bulk or associated with gutta-percha on the fatigue behavior and failure patterns of endodontically treated teeth.

The present in vitro study aimed to evaluate the fatigue behavior of teeth filled with a calcium silicate-based sealer (Bio-C Sealer, BC) or an epoxy resin-based sealer (AH Plus, AH), in bulk or associated with gutta-percha as main core material. Seventy-two sound human maxillary anterior teeth were initially selected. Sixty of them, were randomly chosen, and had their root canals prepared using nickel-titanium reciprocating instruments, being again randomly assigned to five experimental groups (n = 12): C+ (control + prepared but not filled); BC-B (BC in bulk); BC-GP (BC+ gutta-percha); AP-B (AH in bulk); AP-GP (AH+ gutta-percha). An additional negative control group (C-) was considered (n = 12), consisting only on sound teeth, without preparation and filling. The specimens were submitted to a survival analysis after the cyclic fatigue test. Sound teeth (C-) presented the best fatigue performance (P < 0.05), being similar only to the AP-GP group (P > 0.05). Despite that, all experimental groups showed similar fatigue behavior (P > 0.05) to C+ (BC-B = BC-GP = AP-B = AP-GP = C+). Based on that, it can be seen that the use of gutta-percha, as a main core material, associated with the AH Plus sealer, reestablished the mechanical fatigue performance of endodontically treated teeth comparable to sound teeth, still consisting on the most promising approach to rehabilitate such scenario. Teeth filled in bulk, had discreetly higher risk of premature failures and inferior fatigue performance.

In Vitro Evaluation of Root Surface Temperature Using Different Endodontic Filling Techniques

Depending on the obturation technique, the tooth and surrounding tissues may heat up during root canal filling, particularly with warm methods. This study aimed to analyze the temperature increase in the periradicular and -apical region during various warm obturation techniques with a present simulated periodontal blood flow. Seventy-five extracted human teeth were shortened to 11 mm (cut-grinder Primus diamond cutting device; Walter Messner GmbH, Oststeinbek, Germany) and prepared using the ProTaper Gold system (Dentsply Sirona Inc., Charlotte, NC, USA) ISO size 40/.06. Specimens were prepared to ensure stable fluid circulation in an artificially created periodontal space, and the procedure was recorded with a thermal infrared camera (VarioCAM HD; InfraTec GmbH Infrarotsensorik und Messtechnik, Dresden, Germany). The following obturation methods were applied: I, cold single-cone obturation (control group); II, gutta-percha-coated rigid carrier technique (GuttaFusion); III, squirting technique (injection technique); IV, continuous wave technique; and V, Schilder technique. Statistical analysis was performed using the Kruskal–Wallis test, followed by the Mann–Whitney pairwise test using the sequential Bonferroni procedure for significant differences (p &lt; 0.05). The Schilder technique with 0 mL/min showed the lowest temperature change, with a median of 0.00 °C (max. 0.00 °C, min. 0.00 °C, IQR 0.00 °C). In contrast, the continuous wave technique at a circulation rate of 2.6 mL/min exhibited the highest temperature change, with a median of 3.76 °C (max. 5.33 °C, min. 2.42 °C, IQR 1.46 °C). Although warm obturation techniques can increase surface temperature, none of the methods produced changes that were potentially damaging to the periodontium or surrounding bone.

The Effect of Silver Nanoparticles on Bond Strength of Calcium Silicate-Based Sealer: An In Vitro Study

The aim of this study was to evaluate the bond strength of the calcium silicate-based sealer (CSS) modified with the silver nanoparticles (AgNPs) using the single-cone technique (SC) and the continuous wave condensation (CWC) technique, measured by a universal testing machine. The AgNPs and the modified sealers were characterized by scanning electron microscopy and transmission electron microscopy. One hundred single-rooted extracted human permanent teeth with a single root canal were cleaned and shaped with a Protaper Next system. The teeth were randomly divided into four groups (n = 25) as follows: Group 1, canals were obturated using the SC technique with TotalFill® BC Sealer. Group 2, canals were obturated using the SC technique with TotalFill® BC Sealer mixed with AgNPs. Group 3, canals were obturated using the CWC technique with TotalFill® HiFlow BC Sealer. Group 4, canals were obturated using the CWC technique with TotalFill® HiFlow BC Sealer mixed with AgNPs. After two weeks, 1 mm-thick dentin slices were cut and exposed to a push-out bond strength test using a universal testing machine. Specimens were examined under a digital microscope to determine the mode of failure. Statistical analysis was performed using ANOVA and Tukey multiple comparison tests (p &lt; 0.05). The nanoparticle characterization revealed a spherical morphology with no obvious aggregations. The results showed that group 4 had the highest dislodgement resistance compared to all groups (p &lt; 0.05). Group 4 was significantly higher in push-out bond strength value than group 1 (p &lt; 0.001) and group 3 (p &lt; 0.003), but not significantly higher than group 2. Cohesive failure was the most prevalent failure mode among all groups. It can be concluded that the incorporation of silver nanoparticles into the calcium silicate-based sealer significantly increased the bond strength. The warm obturation approach demonstrated significantly higher resistance to dislodgment as compared to the single-cone technique.

Association of LONP1 gene with epilepsy and the sub-regional effect

The LONP1 gene encodes Lon protease, which is responsible for degrading damaged or misfolded proteins and binding mitochondrial DNA. Previously, LONP1 variants have been identified in patients with cerebral, ocular, dental, auricular, and skeletal anomalies (CODAS syndrome) and mitochondrial diseases. Seizures were occasionally observed. However, the association between LONP1 and epilepsy remains elusive. In this study, we performed trio-based whole-exome sequencing in a cohort of 450 patients with unexplained epilepsy and identified four pairs of compound heterozygous LONP1 variants in four unrelated cases. All patients exhibited good responses to anti-seizure medications and demonstrated no developmental delay or intellectual disabilities. The variant allele frequencies observed in this study were absent or low in the general population and were significantly lower than those of benign variants. At least one variant in each biallelic pair affected hydrogen bonding and/or altered protein stability. The CODAS syndrome-associated variants were concentrated in the AAA+ module, especially the α domain. Four of the five mitochondrial disease-associated variants were located in the AAA + domain and the NTD5H and NTD3H subdomains. In contrast, each of the biallelic variants from the patients with pure epilepsy had one variant located in the linker domain, and the other variant located in the mitochondrial targeting sequence or P domain. This study suggested that LONP1 gene is potentially a novel candidate gene for pure epilepsy. The phenotypic variation is associated with the sub-regional effects of variants.

Prevalence of Dental Anomalies in Pediatric Patients visiting Tertiary Care Hospital: A Panoramic Radiograph based study

Introduction: Dental anomalies are deviations from the normal development, structure, or appearance of teeth. These anomalies can affect the number, size, shape, position, and structure of teeth. Objective: This study aimed to assess the prevalence of dental anomalies in the pediatric patients visiting Kathmandu University School of Medical Sciences (KUSMS), Dhulikhel Hospital, Nepal. Methods: A descriptive cross-sectional study was conducted at KUSMS, Dhulikhel Hospital. The panoramic radiographs of the pediatric patients between 6 and 14 years of age in the archive of the hospital were assessed for the presence of dental anomalies. Results: Of the total 451 panoramic radiographs meeting the inclusion criteria, 55.9% were male and 44.1% were female. The overall prevalence of dental anomaly was 26.8 % with rotation as the most common anomaly (19.3%) followed by missing (6.7%), supernumerary teeth (4.4%), dilaceration 2.4 %, gemination (1.8%), dens-in-dente (1.1%) and peg shaped (0.9%). Conclusions: The most common dental anomaly among the pediatric patients was rotation followed by missing and supernumerary tooth.

Antimicrobial and anti-endotoxin activity of N-acetylcysteine, calcium hydroxide and their combination against Enterococcus faecalis, Escherichia coli and lipopolysaccharides.

The management of endodontic infections is a complex challenge, mainly due to the involvement of diverse microorganisms and their by-products. This study aimed to evaluate the efficacy of N-acetylcysteine (NAC), calcium hydroxide (Ca(OH)2), and their combined application as intracanal medications in combating Enterococcus faecalis, Escherichia coli, and lipopolysaccharides (LPS) from E. coli. A total of 60 single-rooted human teeth were carefully selected and divided into six groups. These tooth canals were deliberately exposed to E. faecalis (ATCC 29212) and E. coli (ATCC 25922) to induce biofilm formation. Subsequently, the specimens were treated with NAC, Ca(OH)2, or a combination of both substances. Three samples of the root canals were collected at three moments: the first sample (S1) was to confirm the initial contamination, the second sample (S2) was immediately post-instrumentation, and the third sample (S3) was collected after the use of the intracanal medication. The antimicrobial efficacy of these intracanal medications was assessed by enumerating colony-forming units per milliliter (CFU/mL). In addition to this, the kinetic chromogenic Limulus Amebocyte Lysate (LAL) assay by Lonza was used to quantify LPS from E. coli. Data tested for normality; then, Kruskal-Wallis and Friedman tests were used, and Dunn's for multiple comparisons. The findings of this study showed significant reductions in the microbial load of E. faecalis and E. coli by S3. Notably, there were no statistically significant differences among the treatment groups concerning these microorganisms. However, it was observed that only the combination of NAC and Ca(OH)2 led to a noteworthy decrease in the quantity of E. coli's LPS after 7-days, demonstrating a statistically significant difference from the other treatment groups. NAC + Ca(OH)2 combination, applied for a duration of 7-days, proved to be more suitable in reducing the presence of E. faecalis, E. coli, and LPS from E. coli within the context of endodontic infections.