Search results for "dentistry"

In vitro evaluation of composite resin fluorescence after natural aging

2020

Background Some composite resins contain luminophorous agents in order to reproduce tooth fluorescence. The objective of this study was to compare the fluorescence spectra emitted by composite resins with those of human enamel and dentin, and their emission behaviour after a 90-day natural aging period. Material and Methods Nine shades of the composite resins Z350XT/3M (XT), Opallis/FGM (OP) and Empress Direct/Ivoclar-Vivadent (ED) were analyzed. Five specimens (10.0 mm x 2.0mm) were fabricated for each shade. Enamel (5.0 mm x 0.30 mm) and dentin (5.0 mm x 1.0 mm) specimens were obtained from sound human third molars. Fluorescence spectra of human dentin and enamel as well as the composite …

Comparative evaluation of shear bond strength of universal dental adhesives : an in vitro study

2017

Background Patient demand for tooth colored restorations and desire for minimally invasive restorations have made composites an indispensable part of the restorative process. An important factor affecting the intra-oral performance of composite restorations is bonding. Material and methods Ninty six freshly extracted molar teeth were collected and occlusal 3mm is removed using a diamond disc to expose dentine. Following with samples were divided in to two main groups (self-etch & total etch). Each main group is again sub divided in to three groups each according to bonding agent used (Tetric N- Bond Universal, Single Bond Universal, Tetric N Bond Total etch in total etch group and Clear Fil…

Autologous dental pulp mesenchymal stem cells for inferior third molar post-extraction socket healing : a split-mouth randomised clinical trial

2018

Background Since the discovery of adult mesenchymal stem cells extensive research has been conducted to determine their mechanisms of differentiation and effectiveness in cell therapy and regenerative medicine. Material and Methods To assess the efficacy of autologous dental pulp mesenchymal stem cells delivered in a collagen matrix for post-extraction socket healing, a single-centre, double-blind, randomised, split-mouth, controlled clinical trial was performed. Both impacted mandibular third molars were extracted from 32 patients. Dental pulp was collected and dissociated; the resulting cell suspension, obtained by centrifugation, was incorporated into a resorbable collagen matrix and imp…

Danger zone analysis using cone beam computed tomography after apical enlargement with K3 and K3XF in a manikin model

2015

Background The objective of the study was to evaluate and compare how apical enlargement with K3 and K3XF nickel-titanium (NiTi) rotary instruments reduces the root thickness in the danger zone and affects canal transportation and centering ability in mandibular molar mesial canals in a manikin extracted tooth model. Material and Methods Seventy-two mesial root canals of first mandibular molars were instrumented. Initial and post-instrumentation Cone Beam Computed Tomography scans were performed after root canal preparation up to size 25, 30, 35 and 40 files. Canal transportation, canal centering and remaining root dentin thickness toward the danger zone were calculated in sections 1, 2 and…

Dental pulp calcifications in prehistoric and historical skeletal remains

2020

Abstract Background The prevalence of hard tissue formations in the dental pulp varies considerably. Beside ageing processes and irritations of the dental pulp, etiological associations with cardiovascular disease and dietary habits have been discussed, which are of particular research interest. The aim of this pilot study is to provide new insights on structural and etiological factors involved in the development of pulp calcifications by investigating skeletal remains from different (pre)historic periods. Methods The jaws of 46 skeletons excavated in central Germany, were examined for the presence of pulp stones using digital volume tomography (DVT). A total of 1122 teeth were examined wi…

2020

Many patients regularly take histamine receptor antagonists, such as cetirizine, to prevent allergic reactions, but these antiallergic drugs may have inadvertent effects on orthodontic treatment. In previous studies, histamine has been shown to modulate the sterile inflammatory reaction underlying orthodontic tooth movement. Pertinent effects of histamine antagonization via cetirizine during orthodontic treatment, however, have not been adequately investigated. We thus treated male Fischer344 rats either with tap water (control group) or cetirizine by daily oral gavage corresponding to the clinically used human dosage adjusted to the rat metabolism (0.87 mg/kg) or to a previously published …

Interradicular Root Canals in Mandibular First Molars: A Literature Review and Ex Vivo Study

2019

Abstract Introduction Successful endodontic treatment vastly depends to a high degree on an accurate knowledge of root canal system morphology. It is a prerequisite to be aware of all possible reservoirs where bacteria and/or toxins can persist, compromising the surrounding tissues; such knowledge results in endodontic success. Methods The presence of interradicular canals and diverticula between the pulp chamber floor and the bifurcation area surface of 117 mandibular first molars was investigated. Access cavities were prepared, the teeth were embedded in plastic, and the pulp chambers were flooded with methylene blue and then centrifuged. An average of 4.2 (0.145 ± 0.03 mm thickness) slic…

Three-dimensional analysis of the physiological foramen geometry of maxillary and mandibular molars by means of micro-CT.

2017

The aim of this study was to investigate the physiological foramen diameter, shape and distance between physiological and anatomical apex of maxillary and mandibular first and second molars. Accurate knowledge of the physiological foramina morphology; thus, inherent mechanical shaping technical hindrances, is decisive when taking the corresponding root canal final preparation decision. The morphological dimensions of a total of 1727 physiological foramina were investigated by means of micro-computed tomography. Mean narrow and wide (to a high number, oval) diameters of the physiological foramen were 0.24, 0.22 and 0.33 mm and 0.33, 0.31 and 0.42 mm in mesiobuccal (MB), distobuccal (DB) and …

Ultrasonic techniques to obtain dental pulp from impacted third molars.

2019

Background In the dental clinic impacted teeth are frequent findings, especially upper and lower third molars, leading to their exodontia. Among surgical techniques piezosurgery is advantageous for delicate structures in the oral cavity. Extracted teeth, usually discarded, have been revalued as biological material, providing living tissues with possible applications in regenerative dentistry. The aim was to compare cross-section methods of upper included third molars by ultrasonic piezoelectric technique to obtain dental pulp, with diamond-coated tip (DT) against titanium nitride-coated tip (TN), according to the pulp tissue cell viability and the section surface characteristics. Material a…

Hemodynamic variations and anxiety during the surgical extraction of impacted lower third molars

2019

Background The surgical removal of an impacted third molar can cause patient anxiety. Such anxiety and the use of vasoconstrictor drugs and local anesthetics in turn can induce hemodynamic variations during the operation. A study is made of the variations in hemodynamic parameters (systolic and diastolic blood pressure and heart rate) and their correlation to patient gender and anxiety during surgical removal of an impacted lower third molar. Material and methods A prospective study was carried out in the Oral Surgery Unit of a university clinic, with the inclusion of 125 patients (mean age 24.9 years). Anesthesia was administered in the form of 4% articaine and adrenalin 1:200,000 for surg…