Στην βιολογία, το περιβάλλον μπορεί να καθοριστεί σαν ενα σύνολο κλιματικών, βιοτικών, κοινωνικών και εδαφικών παραγόντων που δρουν σε έναν οργανισμό και καθορίζουν την ανάπτυξη και την επιβίωση του. Έτσι, περιλαμβάνει οτιδήποτε μπορεί να επηρεάσει άμεσα τον μεταβολισμό ή τη συμπεριφορά των ζωντανών οργανισμών ή ειδών, όπως το φως, ο αέρας, το νερό, το έδαφος και άλλοι παράγοντες. Δείτε επίσης το άρθρο για το φυσικό περιβάλλον και τη φυσική επιλογή.
Στην αρχιτεκτονική, την εργονομία και την ασφάλεια στην εργασία, περιβάλλον είναι το σύνολο των χαρακτηριστικών ενός δωματίου ή κτιρίου που επηρεάζουν την ποιότητα ζωής και την αποδοτικότητα, περιλαμβανομένων των διαστάσεων και της διαρρύθμισης των χώρων διαβίωσης και της επίπλωσης, του φωτισμού, του αερισμού, της θερμοκρασίας, του θορύβου κλπ. Επίσης μπορεί να αναφέρεται στο σύνολο των δομικών κατασκευών. Δείτε επίσης το άρθρο για το δομημένο περιβάλλον.
Στην ψυχολογία, περιβαλλοντισμός είναι η θεωρία ότι το περιβάλλον (με τη γενική και κοινωνική έννοια) παίζει μεγαλύτερο ρόλο από την κληρονομικότητα καθορίζοντας την ανάπτυξη ενός ατόμου. Συγκεκριμένα, το περιβάλλον είναι ένας σημαντικός παράγοντας πολλών ψυχολογικών θεωριών.
Στην τέχνη, το περιβάλλον αποτελεί κινητήριο μοχλό και μούσα εμπνέοντας τους ζωγράφους ή τους ποιητές. Σε όλες τις μορφές της Τέχνης αποτελεί έμπνευση και οι Καλές Τέχνες φανερώνουν την επιρροή οπού άσκησε σε όλους τους καλλιτέχνες με όποιο είδος Τέχνης κι αν ασχολούνται. Ο άνθρωπος μέσα στο περιβάλλον δημιουργεί Μουσική, Ζωγραφική, Ποίηση, Γλυπτική, χορό, τραγούδι, θέατρο, αλλά και όλες οι μορφές τέχνης έχουν άμεση έμπνευση από το περιβάλλον.

Τετάρτη 3 Ιουλίου 2019

Conservative Dentistry

With sincere prayers to all humanity
Aditya Mitra, Chandrani Adhikari

Journal of Conservative Dentistry 2019 22(3):215-215



Gutta-percha in endodontics - A comprehensive review of material science
Vijetha Vishwanath, H Murali Rao

Journal of Conservative Dentistry 2019 22(3):216-222

The complete and three-dimensional fluid tight seal of the root canal system is the final component of the endodontic triad. The long-standing and closest material which has fulfilled this criterion is gutta-percha (GP). Several materials have been tried and tested as an endodontic filling material, of which GP has been most extensively used for years and has established itself as a gold standard. In addition, it has proved itself successful with different techniques of obturation while maintaining its basic requisites. This article deals briefly with the history and evolution of GP, source, chemical composition, manufacturing, disinfection, cross-reactivity, and advancements in the material.


Efficacy of different endodontic irrigation protocols on shear bond strength to coronal dentin
Soley Arslan, Hacer Balkaya, Nazire Nurdan Çakir

Journal of Conservative Dentistry 2019 22(3):223-227

Aim: The purpose of this study was to evaluate the effect of etidronic acid on bond strength to coronal dentin. Materials and Methods: A total of 75 human mandibular molars were sectioned 3 mm below the occlusal surface and then randomly divided into five groups according to irrigation solution used (n = 15): Group 1: 5 ml 2.5% sodium hypochlorite (NaOCl) +5 ml distilled water; Group 2: 5 ml 2.5% NaOCl + 5 ml 17% ethylenediaminetetraacetic acid (EDTA); Group 3: 10 ml mixture of 5% NaOCl and 18% 1-hydroxyethylidene-1,1-bisphosphonate (HEBP); Group 4: 5 ml mixture of 5% NaOCl and 18% HEBP + 5 ml 17% EDTA; and Group 5: 5 ml mixture of 5% NaOCl and 18% HEBP + 5 ml distilled water. Thereafter, Clearfil SE bond was applied to the dentin surfaces and then, composite build-ups were created using Tygon tubes for the microshear bond strength test. Data were analyzed using the one-way analysis of variance and Tukey test. Results: When compared to Groups 3, 4, and 5, Groups 1 and 2 showed significantly higher bond strength values (P < 0.05). However, there was no statistically significant difference between Groups 1 and 2 and between Groups 3, 4, and 5 (P > 0.05). Conclusion: HEBP adversely affected the bond strength of the tested adhesive to coronal dentin.


Influence of type of cement and their thickness on stress distribution at dentin-cement interface of computer-aided designed glass fiber post: A three-dimensional finite element analysis
Sonali Taneja, Pragya Kumar, Nitin Gupta, Rabab Khan

Journal of Conservative Dentistry 2019 22(3):228-232

Aim: This study aims to evaluate the effect of type of cement, and their thickness on stress distribution at dentin-cement interface of computer-aided designed glass fiber post using three-dimensional finite element analysis. Materials and Methods: Nine 3D models of endodontically treated maxillary second premolar were divided into three groups according to the adhesive cement used PermaCem (Group I), Variolink II (Group II), and ParaCore (Group III). Each group was further divided into subgroup a, b, and c on the basis of the thickness of the adhesive cement 50 μm, 200 μm, and 300 μm, respectively. All the models were simulated to be cemented with computer-aided designed glass fiber post and core followed by zirconia crown. The core was modeled with incomplete ferrule. The load of 200N at 45° at lingual and central fossa was applied. Maximum von Mises stresses distribution was calculated. Results: Maximum and minimum stresses in dentin were seen in the Ic and IIIa, respectively. Maximum and minimum stresses in cement were seen in IIIc and Ia, respectively. Conclusion: The von Mises stresses in dentin can be minimized by keeping the cement thickness minimum and selecting the cement whose modulus of elasticity is closest to that of dentin.


Morphological measurements of anatomical landmarks in human maxillary first molar pulp chambers and evaluation of number of pulp canal orifices using spiral computed tomography: An in vitro study
Chakshu Gaba, Anuraag Gurtu, Rashmi Bansal, Pramod Kumar

Journal of Conservative Dentistry 2019 22(3):233-236

Context: Comprehensive understanding of the anatomic position of pulp canal orifices and the measurements of the molar pulp space may maintain the pulp health during conservative tooth preparation and minimize the possibility of mishaps during endodontic therapy. Aims: The idea of the present study was to analyze the morphological measurements of anatomical landmarks in human maxillary first molar pulp chambers and evaluation of number of pulp canal orifices using three-dimensional spiral computed tomography (SCT). Subjects and Methods: One hundred and thirty extracted intact human adult maxillary first molars were chosen from the North Indian population and were analyzed using SCT in axial and coronal sections. Statistical Analysis Used: Standard deviation, mean, and coefficient of variance were calculated. Interobserver reliability was evaluated using kappa value to avoid any bias. Results: The results from our study showed that 69.23% of the sample teeth had four canal orifices, the mesial and distal pulp horns were present at an average distance of 0.80 ± 0.36 mm and 0.41 ± 0.34 mm, respectively, above the cementoenamel junction (CEJ), and the mean distance from the central groove of central fossa to furcation and the central groove of central fossa to the pulp chamber's roof was 8.37 ± 0.33 mm and 3.87 ± 0.29 mm, respectively. The average distance of the pulp chamber's floor from the furcation was found to be 2.47 ± 0.11 mm. The highest degree of variance was observed in case of relation of CEJ to pulp horns, i.e., 44.85% and 82.60%. Conclusions: The dimensions observed in this study and its resemblance to the various studies reported in literature shift the fundamental anatomic approach to a more systemic quantifiable approach to the endodontic maxillary first molar access preparation.


In vitro comparison of apical microleakage by spectrophotometry in simulated apexification using White Mineral Trioxide Aggregate, TotalFill Bioceramic Root Repair material, and BioDentine
M Juez, ML Ballester, E Berástegui

Journal of Conservative Dentistry 2019 22(3):237-240

Aim: The purpose of this study was to compare the sealing ability of various calcium silicate-based root-filling materials with a glucose leakage model after orthograde obturation using an open apex model. Materials and Methods: Thirty-two recently extracted human maxillary anterior teeth with single, straight root canals were selected and divided into four groups: Group 1 (G1), White Mineral Trioxide Aggregate; the material was delivered into the canal using the MAP system and further compacted with a specific plugger. Group 2 (G2), TotalFill bioceramic Root Repair material: the material was injected directly into the middle half of the root canal. Group 3 (G3), BioDentine; the material was delivered into the canal using the Hawe composite gun and prefitted pluggers. Statistical Analysis: Statistical analysis was performed using the SPSS 23.0 statistical software package. The Kruskal–Wallis nonparametric test was applied to compare the differences in glucose microleakage. Results: There were no significant differences among the three experimental groups. The results showed a tendency for leakage to increase from the 1st day to the end of experimental period. Conclusions: Within the parameters of this in vitro study, it may be concluded that the three materials evaluated present similar apical microleakage when treating teeth with open apices requiring orthograde delivery of an apical barrier.


Comparing the antimicrobial efficacy of pediocin with chlorhexidine and calcium hydroxide as intracanal medicaments against persistent root canal infections
Hui Ying Ooi, Wan Yi Tee, Fabian Davamani, Venkateshbabu Nagendrababu

Journal of Conservative Dentistry 2019 22(3):241-244

Introduction: The aim of this study is to compare the antimicrobial activity of pediocin with chlorhexidine (CHX) and calcium hydroxide (Ca(OH)2) against Enterococcus faecalis and Staphylococcus epidermidis biofilms. Materials and Methods: The prepared root canals of 80 teeth were contaminated with E. faecalis (n = 40) and S. epidermidis (n = 40) for 21 days to create biofilms. The samples in each group were allocated randomly into the following four subgroups (n = 10) according to the decontamination protocol: Group 1: 1% Pediocin, Group 2: 2% CHX, Group 3: Ca(OH)2, and Group 4: saline (negative control). At 5 days, the antimicrobial efficacy of the medicaments against E. faecalis and S. epidermidis was assessed by collecting dentin shavings from the canal walls created using Gates Glidden drill sizes 4 and 5, corresponding to a depth into the root canal walls of 200 μm and 400 μm, respectively. The total number of colony-forming units (CFUs) was counted. The Wilcoxon signed-rank test was used to compare the difference in CFUs between the two depths (P > 0.05). Results: There was no bacterial growth in samples treated with pediocin, CHX, or Ca(OH)2 at either depth. Conclusion: In this laboratory experimental model, pediocin exhibited the same antimicrobial properties against E. faecalis and S. epidermidis as CHX and Ca(OH)2.


Comparative evaluation of the effect of surface treatment of fiber-reinforced posts and prefabricated metal posts on adhesion of a resin-based luting cement: An in vitro study
Zarir R Ruttonji, Preethi B Kusugal, Ajaykumar Nayak, Deepa Mahajan, KM Sushma, Viraj N Patil

Journal of Conservative Dentistry 2019 22(3):245-248

Background: The purpose of this study was to evaluate the effect of surface treatment of fiber-reinforce post and metal post of adhesion of a resin luting cement. Materials and Methods: Sixty methyl methacrylate specimens were fabricated with a customized metal rod. The samples were segregated into six groups (F1, F2, F3, M1, M2, and M3) of 10 specimens (n = 10) each. The first three groups (F1, F2, and F3) were for fiber posts and (M1, M2, and M3) were for metal posts. The postspace preparation was done with dedicated drills supplied by the postmanufacturers to a length of 14 mm. F1 and M1 were the control groups. The posts in F2 and M2 groups were treated with airborne-particle abrasion with 70 μm Al2O3 particles for 5 s at a constant distance of 20 mm, cleaned with alcohol and cemented in the postspace. The posts in the F3 and M3 groups were treated with airborne-particle abrasion followed by primer application. After cementing the posts into the postspace, the acrylic blocks were sectioned with a motor-driven jigsaw to obtain four specimens each of 3-mm thickness. These sections were then subjected to push-out tests on a universal testing machine. Results: There was a statistically significant increase in the bond strength of both fiber and metal posts to resin cement after airborne-particle abrasion with Al2O3 particles and airborne abrasion followed by primer application. Conclusion: There is an increase in the bond strength of the resin cement with the prefabricated posts after the various surface treatments.


Biocompatibility evaluation of Jordanian Portland cement for potential future dental application
Abubaker S Qutieshat, Ahmad S Al-Hiyasat, Homa Darmani

Journal of Conservative Dentistry 2019 22(3):249-254

Background: The demand for novel Portland cement (PC)-based formulations to be used in dental applications is ever increasing in viewing the foregoing knowledge on the favorable effects of these formulations on cellular proliferation and healing, leading to treatment success. Aim: This study investigated the effect of white and gray mineral trioxide aggregate (W-MTA and G-MTA) and white and gray Jordanian PC (W-PC and G-PC) in their raw state on the viability of Balb/C 3T3 fibroblasts using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Materials and Methods: Materials were prepared in the form of disks, with a diameter of 5 mm and a thickness of 2 mm. In the first experiment, Balb/C 3T3 fibroblasts were cultured with the material disks using culture plate inserts. In the second experiment, material elutes were added to cultured cells. The elutes were prepared by adding 2 ml serum-free media to 10 disks of each material and then incubated at 37°C for different time intervals. Material elutes were analyzed using ion chromatography for traces of calcium. The data were analyzed using analysis of variance followed by Dunnett test (α = 0.05) or Tukey test (α = 0.05). Results: In response to material disks, G-PC had a proliferative effect on cells at day 1 and day 2 with a significant difference from the control at day 1. G-MTA reduced cell viability with a significant difference from the control level at day 2. Elutes of PC showed biocompatible and even proliferative effects on Balb/C 3T3 fibroblasts. Calcium ions were found to leach continuously over the measurement period for all the materials tested in this work. Conclusion: Jordanian PC in its raw state was found to be biocompatible, and the results of this work give promise of its wider use as a base for further development to improve the physiochemical and mechanical properties of the material.


In vitro assessment of interaction between lidocaine hydrochloride and sodium hypochlorite on root canal dentin before and after chemomechanical instrumentation procedures
Balasubramanian Saravanakarthikeyan, Shari Devarajan, Kolli Sankeerthana, Venkatappan Sujatha, Sekar Mahalaxmi

Journal of Conservative Dentistry 2019 22(3):255-259

Introduction: To investigate the effect of resultant precipitate formed on interaction between 2% lidocaine hydrochloride with adrenaline (LA) and 2.5% sodium hypochlorite (NaOCl) on root canal dentin before and after chemomechanical preparation, using scanning electron microscopy (SEM). Methods: Sixty mandibular premolars were decoronated, and the root length was standardized. All specimens were randomly distributed into the following three groups: Group I (control): 2% LA mixed with sterile water without root canal instrumentation, Group II: 2% LA with 2.5% NaOCl and no instrumentation, and Group III: 2% LA with 2.5% NaOCl, followed by mechanical instrumentation with rotary files. Teeth samples were sectioned into three parts, split and SEM analysis of the root canal wall was done at cervical, middle, and apical root thirds. Results: SEM images revealed patent dentinal tubules with no precipitate occlusion in the control group, whereas there was occlusion of dentinal tubules with a precipitate in all the specimens in Group II and Group III at all the three root levels studied. Conclusions: The precipitate formed on the interaction between 2% LA solution and 2.5% NaOCl tends to occlude the dentinal tubules at the coronal, middle, and apical root thirds. The chemomechanical rotary instrumentation procedure did not effectively remove the precipitate from all the three levels of the root specimens studied. LA/sterile water group did not result in any precipitate formation on root canal dentin.


Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182
6948891480

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