NEET MDS Shorts
865232
OrthodonticsAngle Class III Malocclusion:
Angle Classification:
The Angle classification system, developed by Edward Angle, is a
widely used method for categorizing malocclusions based on the
relationship of the first molars and the canines.
Class III Malocclusion:
In Angle Class III malocclusion, the lower first molar is positioned
more mesially (toward the midline) relative to the upper first molar.
This means that when the first molars are in occlusion, the lower first
molar is ahead of the upper first molar.
Clinical Implications:
Class III malocclusion is often associated with a prognathic
mandible (where the lower jaw is positioned forward) or a retruded
maxilla (where the upper jaw is positioned backward). This can lead to
various functional and aesthetic concerns, including difficulties with
biting and chewing, as well as facial profile changes.
377077
OrthodonticsEtiology of Tongue thrust
Fletcher has proposed the following factors as being the cause for tongue thrusting.
Genetic factors : They are specific anatomic or neuromuscular variations in the oro-facial region that can precipitate tongue thrust. e.g. Hypertonic orbicularies oris activity.
Learned behaviour (habit) : Tongue thrust can be acquired as a habit.
The following are some of the predisposing factors that can lead to tongue thrusting:
a. Improper bottle feeding
b. Prolonged thumb sucking
c. Prolonged tonsillar and upper respiratory tract infections
d. Prolonged duration of tenderness of gum or teeth can result in a change in swallowing pattern to avoid pressure on the tender zone.
Maturational : Tongue thrust can present as part of a normal childhood behaviour that is gradually modified as the age advances. The infantile swallow changes to a mature swallow once the posterior deciduous teeth start erupting.
Sometimes the maturation is delayed and thus infantile swallow persists for a longer duration of time.
Mechanical restrictions : The presence of certain conditions such as macroglossia, constricted dental arches and enlarged adenoids predispose to tongue thrust habit.
Neurological disturbance: Neurological disturbances affecting the oro-facial region such as hyposensitive palate and moderate motor disability can cause tongue thrust habit.
Psychogenic factors : Tongue thrust can sometimes occur as a result of forced discontinuation of other habits like thumb sucking. It is often seen that children who are forced to leave thumb sucking habit often take up tongue thrusting.
518361
OrthodonticsSOLUTION
Mechanical approaches for aligning unerupted teeth. Orthodontic traction to pull an unerupted tooth toward the line of the arch should begin as soon as possible after surgery
Ideally a fixed orthodontic appliance should already be in place before the unerupted tooth is exposed, so that orthodontic force can be applied immediately.
If this is not practical, active orthodontic movement should being no later than 2 or 3 weeks post-surgically.
665665
OrthodonticsA cleft palate is a congenital condition that does not inherently affect statural growth. The other factors listed�poor nutrition, chronic diseases, and cardiac diseases�can all have long-term negative impacts on a person's growth and development. Poor nutrition can lead to stunted growth due to insufficient nutrients for bone and tissue development, while chronic diseases and cardiac diseases can impair the body's ability to regulate growth hormones and overall health, potentially leading to growth delays or abnormalities.
831683
OrthodonticsSOLUTION
Simon used the orbital plane (a plane perpendicular to the F-H plane at the margin of the bony orbit directly under the pupil of the eye).
According to Simon, in normal arch relationship, the orbital plane passes through the distal axial aspect of the maxillary canine
Malocclusions described as anteropostenor deviations based on their distance from the orbital plane are as follows:
1. Protraction: The teeth, one or both, dental arches, andYor jaws are too far forward, i.e. placed forward or anterior to the plane as compared to the normal where the plane passes through the distal incline of the canine.
2. Retraction: The teeth, one or both dental arches and/or jaws are too far backward, i.e. placed posterior to the plane than normal
786397
OrthodonticsSOLUTION
The mesial incline of the upper canine occludes with the distal incline of the lower [canine];
the distal incline of the upper canine occludes with the mesial incline of the buccal cusp of the lower first premolar.
444676
OrthodonticsIf the coil and tag of a palatal canine retractor are placed too far distally,
the force applied will tend to move the tooth buccally
(toward the cheek) rather than palatally (toward the
palate), which can hinder the intended movement.
964779
OrthodonticsSOLUTION
The mandible is ossified in the fibrous membrane covering the outer surfaces of Meckel’s cartilages.
These cartilages form the cartilaginous bar of the mandibular arch, and are two in number, a right and a left.
Ossification takes place in the membrane covering the outer surface of the ventral end of Meckel’s cartilage , and each half of the bone is formed from a single center which appears, near the mental foramen, about the sixth week of fetal life.
By the tenth week the portion of Meckel’s cartilage which lies below and behind the incisor teeth is surrounded and invaded by the membrane bone