Vitamin K2 Facilitating Inter-Organ Cross-Talk

This chapter features how vitamin K2 is instrumental in bringing about inter-organ communication, thus facilitating (a) a synthesis/secretion of the endocrine, humoral factors from various organs and (b) physiological responses to the said factors by a multitude of organ systems of the body, thus creating a ‘lattice’ of reciprocal regulatory loops in order to ensure endocrine homeostasis

Vitamin K2 and its Impact on Tooth Epigenetics

The impact of nutritional signals plays an important role in systemic-based «models» of dental caries. Present hypotheses now focus both on the oral environment and other organs, like the nervous system and brain. The tooth is subjected to shear forces, nourishing and cleansing, and its present “support system” (the hypothalamus/parotid axis) relays endocrine signaling to the parotid gland. Sugar consumption enhances hypothalamic oxidative stress (ROS), reversing dentinal fluid flow, thus creating an enhanced vulnerability to the oral bacterial flora. The acid, produced by the oral bacterial flora, then leads to erosion of the dentine, and an irreversible loss of dental enamel layers. This attack brings about inflammatory responses, yielding metalloproteinase-based “dissolution”. However, vitamin K2 (i.e. MK-4/MK-7) may come to the rescue with its antioxidant property, locally (mouth cavity) or systemically (via the brain), thus sustaining/preserving hormone-induced dentinal fluid flow (encompassing oxidative stress) and boosting/magnifying bodily inflammatory responses. However, sugars may also reduce the tooth’s natural defences through endocrine signaling, thus enhancing acid-supported enamel dentine erosion. Vitamin K2 sustains and improves the salivary buffering capacity via its impact on the secretion/flow of calcium and inorganic phosphates. Interestingly, primitive cultures’ diets (low-sugar and high-K2 diets) preserve dental health

Validation of contralateral premolars as the substrate for endodontic comparison studies

AIM: To use micro-CT technology and metrology software to validate the use of contralateral premolars as samples in endodontic comparison studies by comparing them before and after canal instrumentation with one instrumentation system. Furthermore, to determine if contralateral premolar roots will yield non-significantly different outcomes regarding shaping ability (volume), degree of twisting, and three-dimensional shape changes. The null-hypothesis (H0 ) is that there are no differences between the contralateral premolar roots pre- or post-instrumentation. METHODOLOGY: Twenty-eight extracted human contralateral premolars (n=44 contralateral roots) from 12 donor patients were scanned with microcomputed tomography before and after instrumentation. Root canal lengths (RCL) were measured visually using a dental operating microscope, electronic apex locator, and micro-CT scans. Data were analyzed statistically for differences between pre- and post-instrumentation. RESULTS: Instrumentation increased the volume of the canals significantly (P0.05). There was no significant difference (P>0.05) in the shape deviation analysis between contralateral pairs. There was no significant difference (P>0.05) for root canal length between the contralateral pairs for any of the three endometric methods. CONCLUSION: Contralateral premolar root canals were associated with similar changes in terms of volume, three-dimensional shape, and degree of twisting from pre- to post-instrumentation. There was no difference between the contralateral premolar root pairs pre- and post-instrumentation, and the study validates contralateral premolars as samples for root canal comparison studies. The null-hypothesis (H0 ) could not be rejected. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved. This is the peer reviewed version of the following article: Johnsen GF, Sunde PT, Haugen HJ. Validation of contralateral premolars as the substrate for endodontic comparison studies. International Endodontic Journal. which has been published in final form at https://doi.org/10.1111/iej.12902. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

Discrepancy in alloy composition of imported and non-imported porcelain-fused-to-metal (PFM) crowns produced by Norwegian dental laboratories

Even though the use of full ceramic crowns have become a well-established practice in dental clinics compare to the last decade, the use of imported casted porcelain-fused-to-metal (PFMs) crowns is still prevalent. The use of imported PFMs is often economically driven; however, when dentists order PFMs, they do not have capabilities to examine its true alloy content. Therefore, we raise the questions whether cheaper imported PFMs have more discrepancies in alloy content compared to domestically produced PFMs? This study included 62 porcelain-fused-to-metal crowns: 41 produced in Norway and 21 imported. Their alloy-composition was determined non-destructively by EDX and SEM. Imported PFMs demonstrated larger deviations compared with non-imported PFMs. Significant deviation was found in key metallic elements in the different alloys (W, In, Pd, Ag). The detected deviations in key element such as Wolfram and Indium could influence the PFMs service time. These finding may be of international concern

Bulk Fill Composites Have Similar Performance to Conventional Dental Composites

: The aim of the study was to perform comprehensive characterization of two commonly used bulk fill composite materials (SDR Flow (SDR) and Filtek™ Bulk Fill Flowable Restorative (FBF) and one conventional composite material (Tetric EvoCeram; TEC). Eleven parameters were examined: flexural strength (FS), flexural modulus (FM), degree of conversion, depth of cure, polymerisation shrinkage (PS), filler particle morphology, filler mass fraction, Vickers hardness, surface roughness following simulated toothbrush abrasion, monomer elution, and cytotoxic reaction of human gingival fibroblasts, osteoblasts, and cancer cells. The degree of conversion and depth of cure were the highest for SDR, followed by FBF and TEC, but there was no difference in PS between them. FS was higher for bulk fill materials, while their FM and hardness were lower than those of TEC. Surface roughness decreased in the order TEC→SDR→FBF. Bisphenol A-glycidyl methacrylate (BisGMA) and urethane dimethacrylate were found in TEC and FBF eluates, while SDR released BisGMA and triethylene glycol dimethacrylate. Conditioned media accumulated for 24h from FBF and TEC were cytotoxic to primary human osteoblasts. Compared to the conventional composite, the tested bulk fill materials performed equally or better in most of the tests, except for their hardness, elastic modulus, and biocompatibility with osteoblasts

Assessment of Root Canal Similarity in Contralateral Mandibular Incisors

Introduction The purpose of this study was to determine the degree of similarity between contralateral mandibular incisors utilising 3-dimensional (3D) models obtained from micro-computed tomographic (micro-CT) scans of extracted human teeth. The null hypothesis was that contralateral mandibular incisors do not exhibit matching symmetry. Methods Sixty pairs (n = 120) of extracted mandibular incisors were obtained from 30 patients and scanned with micro-CT with a voxel size of 15.0 μm. 3D virtual models of the pulpal cavities were rendered. Geometric morphometric deviation analysis was performed after mirroring, automatic alignment, and co-registration of the models of contralateral teeth root mean square (RMS) errors were calculated. The quantitative analysis of the 3D models included 6 different geometric parameters. Data sets were examined with a 2-sample Kolmogorov–Smirnov test. Post hoc retrospective power analysis was performed to find statistical power (α = 0.05). Results Contralateral pairs had a narrower distribution in deviation than random pairs. Also, contralateral pairs showed a statistically higher similarity coefficient (5 out of 6 geometric parameters) compared to random pairs (P < .001); no difference was found when comparing central to lateral pairs or between Vertucci type I configurations compared to non-type I. RMS errors had significantly lower Contralateral premolars (CPs) values than random pairs (P < .001). Conclusions A high degree of similarity was demonstrated for pairing contralateral mandibular incisors using 3D models. The similarity between contralateral central and lateral incisors suggests that when screened and matched, these 4 teeth might be used in endodontic research where similar root canal anatomy is crucial

Creation of well-balanced experimental groups for comparative endodontic laboratorial studies: a new proposal based on micro-CT and in silico methods

Aim To introduce a new method to select anatomically matched teeth using micro-computed tomographic (micro-CT) technology. Methodology Single-rooted mandibular incisors with a single root canal (n = 60) were selected and distributed into three experimental groups according to the method used for matching 10 pairs of teeth in each group. In group 1, the pairs of mandibular incisors were randomly selected from a pool of teeth. In group 2, teeth were paired based on the measurement of canal width 5 mm from the root apex using radiographs taken from buccolingual and mesiodistal directions. In group 3, teeth were scanned (pixel size of 14.25 μm) and pair-matched based on the anatomical aspects of the root canal, named aspect ratio (AR), volume and three-dimensional canal geometry. After allocating the specimens into groups 1 and 2, the teeth were scanned and the canal morphology evaluated as in group 3. A bivariate Pearson’s regression analysis was performed correlating the individual AR values of each pair and the correlation coefficient was used to estimate the strength of the pair-matching process. One-way ANOVA post hoc Tukey tests were applied for pair-wise comparisons at a significance level of 5%. Results The micro-CT method showed 100% of the samples having strong (80%) or very strong (20%) correlations with respect to AR values. Analysis of the radiographic method revealed strong correlation in two pairs (20%), but most of the samples had weak (30%) or neglectable (30%) correlation coefficients. The randomization method resulted in 3 pairs (30%) with very strong correlations, while 50% had weak or neglectable rates. A significant difference in correlation coefficients was observed in the micro-CT method compared to the other groups (p 0.05). Eta squared (η 2 ) calculations demonstrated a very high effect size in the micro-CT group for selecting pairs (0.99), and lower effect sizes in the radiographic (0.67) and randomized (0.66) groups. Conclusions Micro-CT method was able to provide better control of the confounding effect tha