Antifungal Effects of Synthetic Human Beta-defensin-3-C15 Peptide on Candida albicans–infected Root Dentin

Introduction

The aim of this study was to assess the antifungal efficacy of a synthetic human beta-defensin-3-C15 peptide (HBD3-C15) in Candida albicans–infected human root dentin.

Lactobacillus plantarum Lipoteichoic Acid Inhibits Oral Multispecies Biofilm

Introduction

Apical periodontitis is an inflammatory disease in the periradicular region of teeth that results from infection by multispecies bacterial biofilm residing in the root canal system. In this study, we investigated whether Lactobacillus plantarum lipoteichoic acid (Lp.LTA) could inhibit multispecies oral pathogenic bacterial biofilm formation.

Comparison of Alternative Image Reformatting Techniques in Micro–Computed Tomography and Tooth Clearing for Detailed Canal Morphology

Introduction

Micro–computed tomography (MCT) shows detailed root canal morphology that is not seen with traditional tooth clearing. However, alternative image reformatting techniques in MCT involving 2-dimensional (2D) minimum intensity projection (MinIP) and 3-dimensional (3D) volume-rendering reconstruction have not been directly compared with clearing. The aim was to compare alternative image reformatting techniques in MCT with tooth clearing on the mesiobuccal (MB) root of maxillary first molars.

Methods

Eighteen maxillary first molar MB roots were scanned, and 2D MinIP and 3D volume-rendered images were reconstructed. Subsequently, the same MB roots were processed by traditional tooth clearing. Images from 2D, 3D, 2D + 3D, and clearing techniques were assessed by 4 endodontists to classify canal configuration and to identify fine anatomic structures such as accessory canals, intercanal communications, and loops.

Results

All image reformatting techniques in MCT showed detailed configurations and numerous fine structures, such that none were classified as simple type I or II canals; several were classified as types III and IV according to Weine classification or types IV, V, and VI according to Vertucci; and most were nonclassifiable because of their complexity. The clearing images showed less detail, few fine structures, and numerous type I canals. Classification of canal configuration was in 100% intraobserver agreement for all 18 roots visualized by any of the image reformatting techniques in MCT but for only 4 roots (22.2%) classified according to Weine and 6 (33.3%) classified according to Vertucci, when using the clearing technique.

Conclusions

The combination of 2D MinIP and 3D volume-rendered images showed the most detailed canal morphology and fine anatomic structures.     

Effect of 1440-Nanometer Neodymium:Yttrium-Aluminum-Garnet Laser Irradiation on Pain and Neuropeptide Reduction: A Randomized Prospective Clinical Trial

Introduction

The purpose of this study was to investigate the efficacy of a 1440-nm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser on relieving pain in relation to the levels of inflammatory cytokine and neuropeptides in the root canal exudates of teeth with persistent symptomatic apical periodontitis.

Methods

Forty teeth with persistent symptomatic apical periodontitis were randomly assigned to treatment groups: group L, intracanal irradiation of 1440-nm Nd:YAG laser with a 300-μm-diameter fiberoptic tip in addition to conventional root canal retreatment, and group C, conventional root canal re-treatment. The degrees of both spontaneous pain and the pain on percussion before and after treatment were recorded, and root canal exudate samples were collected to quantify the associated levels of substance P, calcitonin gene-related peptide (CGRP), and matrix metalloproteinase (MMP)-8 by immunoassay.

Results

All of the measured parameters were significantly reduced in group L (P < .05), whereas the level of pain on percussion, CGRP, and MMP-8 were significantly reduced in group C (P < .05). The 1440-nm Nd:YAG laser had significantly better effect on the relief of pain on percussion and the reduction of substance P, CGRP, and MMP-8 levels. The visual analog scale scores of perceived pain correlated with pain-related neuropeptides and inflammatory cytokine levels in root canal exudates.

Conclusions

The 1440-nm Nd:YAG laser irradiation via fiberoptic tip to the teeth with persistent apical periodontitis provided promising consequences of pain and inflammation modulation.     

Effect of Conditioned Medium from Preameloblasts on Regenerative Cellular Differentiation of the Immature Teeth with Necrotic Pulp and Apical Periodontitis

Introduction

The purpose of this study was to investigate the effect of conditioned medium (CM) from murine preameloblasts on the cellular differentiation of mesenchymal stem cells (MSCs) in immature teeth with necrotic pulp and apical periodontitis.

Methods

Pulp necrosis and apical periodontitis were induced in 30 immature permanent double-rooted premolars of 3 beagles and were randomly assigned to the following treatment groups: group CM (n = 10), revascularization treatment was performed using CM from preameloblasts of C57BL/6 mice apical bud cells; group CR (n = 10), conventional revascularization treatment was performed; positive control group (n = 5), left infected; and negative control group (n = 5), untreated. The dogs were followed up for 12 weeks and assessed for treatment outcomes with radiographic and histologic analyses. The effect of the CM on sequential Runx2 and osterix messenger RNA gene expression during the differentiation of MG63 osteoblastlike cells was analyzed with real-time polymerase chain reaction.

Results

The overall treatment outcomes were not significantly different between the 2 treatment groups. However, the teeth in the CM group showed significantly more mature apices and a higher degree of hard tissue formation with projections intercalating into the pre-existing root dentin (P < .05). In CM-treated teeth, regenerated pulplike tissue was more frequently observed (P < .05). During differentiation, the CM induced early peak expression of Runx2 followed by sustained osterix overexpression.

Conclusions

CM from preameloblasts rendered a favorable effect in providing a physiologic microenvironment for the differentiation of MSCs after revascularization treatment.     

Dentinal tubule sealing effects of 532-nm diode-pumped solid-state laser,gallic acid/Fe<Superscript>3+</Superscript> complex,and three commercial dentin desensitizers

The purpose of this study was to compare dentinal tubule sealing effects of a 532-nm diode-pumped solid-state (DPSS) laser, gallic acid/Fe³⁺ complex, and three commercially available dentin desensitizers. Human premolars (n?=?44) extracted for orthodontics had standardized cervical cavities prepared, etched (37% phosphoric acid) and randomly assigned to either a control (n?=?4), or one of five treatment groups (n?=?8/group). Desensitizing treatments were either a 532-nm DPSS laser, gallic acid/Fe³⁺ complex, oxalate-based Super Seal? (SS), DIO? Enamel Coating Pen Pro Tooth (Dio), or adhesive-type Hybrid Coat? (HC). Dentinal fluid flow (DFF) was monitored continuously in real time during the application of each desensitizing agent, by using a nanoliter-scaled fluid flow-measuring device. Following treatment, morphological changes on dentinal surfaces and within tubules were observed by scanning electron microscopy (SEM). DFF rates were significantly reduced after treatment in all experimental groups (P?<?0.05), except SS (P?>?0.05). The gallic acid/Fe³⁺ complex reduced DFF rates the most, and significantly (P?<?0.05) more than the three commercial dentin desensitizers. There were no significant differences in DFF reduction rates between the gallic acid/Fe³⁺ complex and the DPSS laser groups (P?>?0.05). There were no significant differences in DFF reduction rates among the three commercial dentin desensitizers (P?>?0.05). SEM examination of treated dentin showed that the degree of occlusion of dentinal tubules correlated closely with the corresponding reduction in DFF rates. The gallic acid/Fe³⁺ complex and 532-nm DPSS laser were superior to other desensitizing methods in occluding dentinal tubules and reducing DFF rates.     

Morphological measurements of two separate mesiobuccal canals in maxillary first molars using micro-computed tomography

Objectives

To obtain radicular measurements of two separate mesiobuccal (MB) root canals in maxillary first molars using micro-computed tomography (μCT) with customized software.

Materials and methods

Human maxillary first molar MB roots (N = 36) with two separate canals (MB1, MB2) and apical foramina were scanned by μCT and analyzed with Kappa2 software to reconstruct three-dimensional (3D) surface models of roots and canals. These models were sectioned at 0.1 mm intervals perpendicular to the central axis of each canal. Canal widths, 3D curvatures, and surrounding dentine thicknesses were measured concurrently on each section. Dentine thicknesses were analyzed statistically for differences between each direction and the different levels of both canals.

Results

Dentine walls around MB1 were thicker than MB2 (p < 0.05). Thinnest dentine was most often located at disto-inside direction in both canals. Canal widths were significantly smaller in MB2 than MB1 (p < 0.01). Apical constrictions were smaller (p < 0.05) and further (p < 0.05) from the apex in MB2 than MB1. Canal curvatures were greatest in the apical third of both canals (p < 0.001), and they were greater in MB2 than MB1 (p < 0.05).

Conclusions

MB2 canals had shorter lengths, smaller widths, and more severe curvatures and were surrounded by thinner dentine walls. In MB2, apical constrictions were between 1 and 2 mm from the apex, compared to about 1 mm for MB1.

Clinical relevance

These detailed measurements and in-depth 3D analyses of maxillary first molar MB roots with two separate canals and apical foramina provide morphologic references for root canal therapy.

     

Effect of mineral trioxide aggregate plug location on root development in regenerative endodontic procedure

Odontology - This retrospective study investigated the effect of mineral trioxide aggregate (MTA) plug location on treatment outcome and root maturation after regenerative endodontic procedures...     

Bacterial entombment by intratubular mineralization following orthograde mineral trioxide aggregate obturation:a scanning electron microscopy study

The time domain entombment of bacteria by intratubular mineralization following orthograde canal obturation with mineral trioxide aggregate（MTA） was studied by scanning electron microscopy（SEM）. Single-rooted human premolars（n560） were instrumented to an apical size #50/0.06 using ProF ile and treated as follows： Group 1（n510） was filled with phosphate buffered saline（PBS）; Group 2（n510） was incubated with Enterococcus faecalis for 3 weeks, and then filled with PBS; Group 3（n520） was obturated orthograde with a paste of OrthoM TA（BioM TA, Seoul, Korea） and PBS; and Group 4（n520） was incubated with E. faecalis for 3 weeks and then obturated with OrthoM TA–PBS paste. Following their treatments, the coronal openings were sealed with PBS-soaked cotton and intermediate restorative material（IRM）, and the roots were then stored in PBS for 1, 2, 4, 8 or 16 weeks. After each incubation period, the roots were split and their dentin/MTA interfaces examined in both longitudinal and horizontal directions by SEM. There appeared to be an increase in intratubular mineralization over time in the OrthoM TA-filled roots（Groups 3 and 4）. Furthermore, there was a gradual entombment of bacteria within the dentinal tubules in the E. faecalis inoculated MTA-filled roots（Group 4）. Therefore, the orthograde obturation of root canals with OrthoM TA mixed with PBS may create a favorable environment for bacterial entombment by intratubular mineralization.