What causes curve of Spee?
Extrusion of posterior teeth Progressively increasing step bends in an archwire also levels the curve of Spee. Other common methods include the use of a bite plate, which allows the posterior teeth to erupt.
What is flat curve of Spee?
Curve of Spee (CoS) is characterized as human occlusal curvature viewed in the sagittal plane. This naturally occurring phenomenon has clinical importance in orthodontics and prosthodontic dentistry. The purpose of this article is to examine the formation of the CoS regarding of when, how, or why the CoS develops.
What is the curve of Spee and curve of Wilson?
 The curve of Spee is designed to permit protrusive disocclusion of the posterior teeth by the combination of anterior guidance and condylar guidance, and the curve of Wilson also permits lateral mandibular excursions free from posterior interferences.
Where is the curve of Wilson seen?
The curve of Wilson is the across arch curvature or posterior occlusal plane. Arc of the curve, which is concave for mandibular teeth and convex for maxillary teeth are defined by a line drawn from left mandibular first molar to right mandibular first molar.
What is deciduous tooth?
Deciduous teeth are also called children’s teeth, baby teeth or first teeth. Deciduous teeth are smaller and whiter than permanent teeth. We only have 20 deciduous teeth. They start to erupt when we’re around 6 months old, and are usually all through when we’re 29 months old.
How do you measure a curved Spee?
The depth of curve of Spee was measured as the perpendicular distance between the deepest cusp tip and a flat plane that was laid on the top of the mandibular dental cast, touching the incisal edges of the central incisors and the distal cusp tips of the most posterior teeth in the lower arch [Figure 1].
What is plate tectonics?
Plate tectonics is a scientific theory that explains how major landforms are created as a result of Earth’s subterranean movements. The theory, which solidified in the 1960s, transformed the earth sciences by explaining many phenomena, including mountain building events, volcanoes, and earthquakes.
What is the speed of plate tectonics?
Plate motions range up to a typical 10–40 mm/year ( Mid-Atlantic Ridge; about as fast as fingernails grow), to about 160 mm/year ( Nazca Plate; about as fast as hair grows). The driving mechanism behind this movement is described below.
What are microplate tectonics?
Microplates are smaller fragments of tectonic plates that appear in plate boundary zones. The crust of our planet is constantly evolving and changing. It is a dynamic structure and this can be best seen whenever an earthquake occurs.
What is an example of tectonics on a sphere?
“The North Pacific: an example of tectonics on a sphere”. Nature. 216 (5122): 1276–1280. Bibcode: 1967Natur.216.1276M. doi: 10.1038/2161276a0.