Le Fort I Osteotomy
Le Fort I Osteotomy - Related Videos
08:37
Le Châtelier's Principle
0 Views •
2023
Source: Laboratory of Dr. Lynne O'Connell — Boston College When the conditions of a system at equilibrium are altered, the system responds in such a way as to maintain the equilibrium. In 1888, Henri-Lewis Le Châtelier described this phenomenon in a principle that states, "When a change in temperature, pressure, or concentration disturbs a system in chemical equilibrium, the change will be counteracted by an alteration in the equilibrium composition." This experiment demonstrates Le Châtelier's...
02:27
Le Chatelier's Principle: Changing Concentration
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2020
A system at equilibrium is in a state of dynamic balance, with forward and reverse reactions taking place at equal rates. If an equilibrium system is subjected to a change in conditions that affects these reaction rates differently (a stress), then the rates are no longer equal and the system is not at equilibrium. The system will subsequently experience a net reaction in the direction of a greater rate (a shift) that will re-establish the equilibrium. This phenomenon is summarized by Le...
02:19
Le Chatelier's Principle: Changing Temperature
0 Views •
2020
Consistent with the law of mass action, an equilibrium stressed by a change in concentration will shift to re-establish equilibrium without any change in the value of the equilibrium constant, K. When an equilibrium shifts in response to a temperature change, however, it is re-established with a different relative composition that exhibits a different value for the equilibrium constant. To understand this phenomenon, consider the elementary reaction: Since this is an elementary reaction, the...
02:32
Le Chatelier's Principle: Changing Volume (Pressure)
0 Views •
2020
For gas-phase equilibria, changes in the concentrations of reactants and products can occur with altered volume and pressure. The partial pressure, P, of an ideal gas is proportional to its molar concentration, M. So changes in the partial pressures of any reactant or product are essentially changes in concentrations; therefore, these changes yield the same effects on equilibria. Aside from adding or removing reactants or products, the pressures (concentrations) of species in a gas-phase...
07:41
An Intramedullary Locking Nail for Standardized Fixation of Femur Osteotomies to Analyze Normal and Defective Bone Healing in Mice
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Cited by 10 •
2016
This protocol describes an osteosynthesis technique using an intramedullary locking nail for standardized fixation of femur osteotomies, which can be used to analyze normal and defective bone healing in mice.
FAQs
Surgeons make horizontal cuts above the tooth roots and extend them along the maxillary walls through an intraoral approach. These cuts create a mobile tooth-bearing segment while preserving the planned relationship of the teeth within the upper jaw. Once mobilized, the segment can be repositioned to address the skeletal discrepancy identified during treatment planning.
The maxilla may be moved vertically, horizontally, or rotationally, and each direction addresses a different component of jaw imbalance. Vertical adjustment can help manage excessive or insufficient upper-jaw height, while horizontal movement addresses forward or backward discrepancies. Rotational repositioning can contribute to correction of asymmetry or bite relationships that are not adequately treated with a single-direction movement.
Plates and screws secure the mobilized maxillary segment in its planned position after the bone cuts and repositioning are complete. This fixation maintains the intended relationship between the upper jaw and the surrounding facial structures while the surgical correction is established. Its role is therefore mechanical stabilization of the repositioned segment, not adjustment of the teeth through orthodontic movement.
It is considered when the underlying problem is a skeletal discrepancy that orthodontic tooth movement cannot correct by itself. Examples include maxillary deficiency or excess, open bite, facial asymmetry, and other jaw discrepancies. In these situations, repositioning the upper jaw addresses the bony relationship directly, while orthodontics can address the dental alignment associated with the corrected skeletal position.
The procedure uses an intraoral surgical approach, followed by horizontal bone cuts above the tooth roots and cuts along the maxillary walls. The surgeon then mobilizes the tooth-bearing upper-jaw segment, moves it vertically, horizontally, or rotationally according to the planned correction, and secures it with plates and screws. The workflow links bone separation, planned repositioning, and fixation.
By correcting the upper-jaw relationship, Le Fort I osteotomy can restore dental occlusion and improve facial proportions. The resulting correction may also improve chewing and speech, with selected airway-related outcomes reported as an additional benefit. These effects depend on the skeletal discrepancy being treated and on how the maxilla is repositioned within the overall jaw relationship.