MDS PREP
Which one of these is the etiological factors of tongue thrust?
1) Hyposensitive palate
2) Hypertonic orbicularis oris activity
3) Macroglossia
4) All of these
Orthodontics Answer: 4
Etiology 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.
A child is 7-year-old skeletal class I relation. He has the habit of thumb sucking. There is slight overjet and anterior spacing. If he discontinue the habit
1) Overjet will reduced
2) Overjet increases as permanent canines erupt
3) Lower incisors incline labially
4) Result in crowding of anterior teeth
Orthodontics
Answer: 1
In a child with a skeletal Class I relationship and slight overjet, thumb sucking can contribute to the maintenance of the overjet due to the anterior teeth being pushed forward by the thumb. If the child discontinues thumb sucking, the anterior teeth may naturally reposition themselves, leading to a reduction in overjet.
Option 2 is incorrect because while the eruption of permanent canines can influence the occlusion.
Option 3 is also incorrect; the lower incisors would not necessarily incline labially if the thumb sucking habit is stopped.
If the tooth has not erupted to the line of occlusion it is called
1) Supraversion
2) Torsiversion
3) Rotated
4) Infraversion
Orthodontics Answer: 4
Terms used to describe the position of teeth.
Mesioversion - A tooth in the arch located more mesial than normal
Distoversion - A tooth in the arch located more distal than normal
Labioversion - An incisor or canine outside of arch towards the lips
Buccoversion - A posterior tooth outside the arch toward the cheek
Linguoversion - A tooth inside the arch form toward the tongue
Infraversion - A tooth that has not erupted to the occlusal plane
Supraversion - A tooth the has over-erupted
Torsiversion - A tooth rotated on its axis
Transversion (Transposition) - Teeth that are in the wrong sequential order.
Transitional phase of dentition is
1) During eruption of permanent and exfoliation of deciduous teeth
2) After all permanent teeth have erupted
3) Phase during correction of malocclusion
4) None of the above
Orthodontics
Answer: 1
The transitional phase of dentition refers to the period when the primary (deciduous) teeth are being replaced by permanent teeth. This phase is characterized by the simultaneous eruption of permanent teeth and the exfoliation (loss) of primary teeth. It typically occurs between the ages of 6 and 12 years. The other options do not accurately describe this transitional phase; option 2 refers to a post-transitional phase, while option 3 pertains to orthodontic treatment rather than a specific phase of dentition.
Which of the fibers attached to cementum are most likely to contribute to relapse of tooth rotation:
1) Gingival group of fibers
2) Apical fibers
3) Horizontal fibers
4) Oblique fibers
Orthodontics Answer: 1
SOLUTION
Gingival group of fibers
Principal fibers of the periodontal ligament rearranges themselves quite rapidly to the position in about 4 weeks.The supra-alveolar gingival fiber take as much as 40 weeks to rearrange around the new position and thus predispose to relapse.
Which of the following are included in the Orthodontic camouflage methods for treating class II malocclusion?
1) Retraction of upper teeth and forward movement of lower teeth
2) Retraction of maxillary incisors into pre-molar extraction space
3) Distal movement of maxillary molars
4) All of the above
Orthodontics Answer: 4
SOLUTION
The following three patterns of tooth movement can be used to correct a Class II malocclusion:
· A combination of retraction of the upper teeth and forward movement of the lower teeth, without tooth extractions
· Retraction of maxillary incisors into a premolar extraction space
· Distal movement of maxillary molars and eventually the entire upper dental arch
The basic principle of Orthodontic spot welder lies on the concept of :-
1 Heat technique
2) Quenching
3) Diodelasers
4) Electrode Technique
Orthodontics Answer: 4
SOLUTION
The type of welding used to join Orthodontic components is called Spot welding. The heat source usually a high amperage electricity. Orthodontic spot welders employ the electrode technique, in which current is conducted through two copper electrodes. The copper electrode in a welding unit serve the following purposes :
1. Transmit current to the metals to be joined so as to cause a rapid increase in temperature.
2. The electrodes help in conducting the heat produced away from the area so as to preserve the properties of stainless steel around the weld spot.
3. The electrode also help in holding together the two metals to be joined.
4. The electrodes are designed to apply pressure on the metals being joined. As soon as the temperature increases, the pressure exerted by the electrodes helps in squeezing metal into each other.
In mixed dentition, which of the following may be considered as a self correcting problem with age?
1) Unilateral loss of primary canine
2) Lack of interdental spaces
3) A distal step
4) Open bite
Orthodontics Answer: 2
SOLUTION
The possibility that a distal step would become class II is very real, and this not self correcting problem. When the central incisors erupt, these teeth use up essentially all of the excess space in the normal primary dentition. With the eruption of the lateral incisors, space becomes tight in both arches.
Normal child will go through a transitory stage of mandibular incisor crowding at age 8 to 9 even if there will eventually be enough room to accommodate all the permanent teeth in good alignment. In other words, a period when the mandibular incisors are slightly crowded is a normal developmental stage.
Continued development of the arches improves the spacing situation, and by the time the canine teeth erupt, space is once again adequate.