Search results for "In vitro study"
showing 10 items of 99 documents
Radiographic Investigation of Frequency and Location of Root Canal Curvatures in Human Mandibular Anterior Incisors In Vitro
2007
The aim of the present in vitro study was to evaluate the degree and location of root canal curvatures of mandibular anterior incisors. A total of 396 extracted human permanent anterior incisors (248 central and 148 lateral) were included in this investigation. Exclusion criteria were teeth with extensive carious lesions, restorations, and root canal treatment. The specimens were fixed in a special device and digitally x-rayed (Heliodent MD; Sirona, Benzheim, Germany; Merlin 2.1, Olympus/PerkinElmer, Waltham, MA) with the parallel technique. The distances from the cementoenamel junction (CEJ) to the first curvatures as well as the according angles were recorded. The results were analyzed de…
Methodology in specimen fabrication for in vitro dental studies: Standardization of extracted tooth preparation
2017
Background Specimen preparation for in vitro study suffers a general lack of methodological homogeneity, as well as a lack of uniformity in the materials selected for fabricating them. This situation prevents comparisons between studies. When a specimen is not of dental origin it is not possible to study adhesion or bonding techniques realistically. The objective is to design and implement a method of specimen preparation that permits universal standardization for use in in vitro studies. Material and Methods A metal stump of specified dimensions was designed and fabricated by hand. It was scanned, the data digitalized, perfecting and standardizing the dimensions. Ten human molars were adap…
The effect of orthodontic bracket pad shape on shear bond strength, an in vitro study on human enamel
2018
Background To evaluate the effect of bracket pad shape on shear bond strength (SBS) of orthodontic brackets bonded to human enamel. Material and Methods One hundred and five extracted human maxillary permanent molars were divided into 7 groups of 15 specimens per group (n=15). Each group of teeth was bonded with 6 different shaped WildSmiles® brackets (Star, Heart, Soccer ball, Football, Flower, and Diamond) and GAC® rectangle shaped brackets. Shear debonding force was measured with an Instron universal testing machine using a knife-edged chisel 24 hours after initial bonding. Descriptive statistics (mean, standard deviation, and range) for each bracket pad shape was calculated. Analysis of…
Bone height measurement of maxillary and mandibular bones in panoramic radiographs of edentulous patients
2011
Objectives. The purpose of this in vitro study were to determine variation in maxillary and mandibular vertical measurements and to assess vertical bone loss made from panoramic radiographs in edentulous measurements. Study Design. In this descriptive study, a total of 600 panoramic radiograph’s of edentulous patient were examined. The mean ages of edentulous patients were 31 and 87 years respectively. Measurements were made from reference lines drawn from anatomic landmarks on standardized panoramic rediographs. All radiographs were made using a standardized manner by the same technician. Twelve sites were measured on every panoramic radiograph whenever possible, five sites in the maxilla …
Determination of the facial/oral alveolar crest using RF-echograms. An in vitro study on the periodontium of pigs.
1989
Abstract This study is a part of a research project in which we have been investigating the use of the ultrasonic pulse echo technique as a means of determining in vivo the facial/oral alveolar crest precisely and routinely. Here, RF-echograms are presented, showing the facial/oral periodontium of pigs. These echograms have been produced using a focussed 20 MHz transducer and a special design of an ultrasonic measuring and analysis system. In one series of measurements on macerated periodontia of pigs we found out that RF-echograms characteristic of a particular level of the facial/oral pericrestal aspect can be achieved. Based upon these results, we succeeded in determining exactly the hei…
In vitro investigation of the impact of remaining tooth structure on the tensile failure loads of overdenture copings
2019
Background The purpose of this in vitro study was to evaluate the impact of the remaining tooth structure on the retention of overdenture cast metal copings. Material and Methods A freshly extracted intact mandibular human canine (length 25 mm) was selected and endodontically treated. An incisal reduction of 4 mm with no ferrule preparation was performed and a post space of 12 mm was created. By using polyvinyl siloxane duplication material and autopolymerizing polymethylmethacrylate resin, ten resin teeth analogs (control group) were obtained. A second set of ten resin teeth analogs (group 1) was created by preparing on the original natural tooth a 360o ferrule design of 1 mm in height and…
Evaluation of accuracy of various impression techniques and impression materials in recording multiple implants placed unilaterally in a partially ed…
2018
Background Various factors like implant angulation, type of impression material and tray type affects the implant impression accuracy. To date limited in-vitro studies were carried out on the implant impression accuracy of unilateral partially edentulous arches. The aim of this research was to evaluate the effects of 0o, 15o and 25o implant angulations on impression accuracy in simulated master casts of unilateral partially edentulous situation using different impression materials and tray selections. Material and Methods 30 replicas (N = 30) of a resin matrix (control) containing four implant analogues placed unilaterally from the midline till the region of second molar at an angulation of…
Comparison of Shaping Ability of 10 Rotary and Reciprocating Systems: an In Vitro Study with AutoCAD
2017
Cilj: Usporediti reznu površinu, očuvanje anatomije korijenskog kanala i neinstrumentiranu površinu nakon instrumentacije sustavima F360®, F6SkyTaper®, HyflexEDM®, iRace®, Neoniti®, O.Shape®, P.Next®, Reciproc®, Revo-S® i WaveOneGold® s veličinom instrumenta 25. Materijali i metode: Tristo zubi s jednim ravnim korijenom i okruglim ili eliptičnim presjekom korijenskog kanala podijeljeno je u 10 skupina (1-F360®, 2-F6SkyTaper®, 3-HyflexEDM®, 4-iRace®, 5-Neoniti®, 6-O Shape®, 7-P.Next®, 8-Reciproc®, 9-Revo-S® i 10-WaveOneGold®) i poprečno prerezano na trećine ultrafinim reznim diskovima. Uzorci su fotografirani pod stereomikroskopom i provedena je predinstrumentacijska analiza prije ponovnog s…
Radiographic Investigation of Location and Angulation of Curvatures in Human Maxillary Incisors
2008
The aim of this radiographic study was to evaluate the degree and location of root canal curvatures of human maxillary incisors. A total of 286 extracted human maxillary incisors (145 central and 141 lateral incisors) were included in this investigation. Exclusion criteria were teeth with extensive carious lesions, restorations, and root canal treatment. For this in vitro study, the teeth were fixed in a special device and digitally x-rayed with the parallel technique. The distances from the cementoenamel junction (CEJ) to the first curvature and the according angle were recorded. The results were analyzed descriptively, and p values were calculated with the Wilcoxon Mann-Whitney test. The …
Association between maxillary and mandibular apical base lengths and severity of dental crowding or spacing in Class II malocclusion subjects: An
2018
Background Anterior crowding/ spacing are one of the major problems that inspire patients to undergo orthodontic treatment. Several factors associated with anterior crowding/ spacing includes arch width and length, mesio-distal tooth diameter and proportions. The aim of the present study was to evaluate the relationship of maxillary and mandibular base lengths to the amount of anterior dental crowding/ spacing in patients with complete class II malocclusions. Material and methods A retrospective study was done with 152 patients who were divided into four groups according to the severity of pre-treatment dental crowding/spacing present in the mandibular arch. Measurements were performed on t…