MDS PREP
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.
Ashley-Howe model analysis is used to predict
1) Tooth material excess
2) Maxillo - mandibular relationships
3) Basal bone-transverse relationship
4) Growth prediction
Orthodontics
Answer: 3
Ashley-Howe Model Analysis
The Ashley-Howe model analysis is a method used in
orthodontics to assess the relationship of the dental arches and the position of
the teeth, particularly in the context of planning orthodontic treatment. This
analysis is particularly useful for evaluating the transverse dimension of the
dental arches and understanding how the maxilla (upper jaw) and mandible (lower
jaw) relate to each other.
Measurement Parameters:
The analysis involves measuring specific distances and angles on dental
casts or models. Key measurements may include:
Intercanine Width: The distance between the cusp
tips of the canines.
Interpremolar Width: The distance between the cusp
tips of the first premolars.
Intermolar Width: The distance between the cusp
tips of the first molars.
These measurements help in determining the transverse relationships of
the dental arches.
Classification:
The results of the Ashley-Howe analysis can help classify the dental
arch relationships into different categories, such as:
Normal: Where the measurements fall within the
expected range.
Narrowed: Indicating a constricted arch that may
require expansion.
Widened: Indicating a broader arch that may need to
be reduced or managed differently.
Clinical Application:
The Ashley-Howe model analysis is particularly useful in treatment
planning for orthodontic cases involving:
Crossbites: Where the upper teeth are positioned
inside the lower teeth.
Crowding: Where there is insufficient space for
teeth to erupt properly.
Expansion Needs: Determining if a patient requires
arch expansion to correct transverse discrepancies.
Treatment Implications:
Based on the analysis, orthodontists can decide on appropriate treatment
modalities, which may include:
Orthodontic Appliances: Such as expanders to widen
the arch.
Extraction: In cases of severe crowding or when
space needs to be created.
Comprehensive Orthodontic Treatment: To align the
teeth and improve occlusion.
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.
An increase or decrease in the Y axis is related to:
1) The growth pattern
2) Extrusion of molars
3) Intrusion of molars
4) All of the above
Orthodontics Answer: 1
SOLUTION
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 classifying molar relation in patient with premature loss of primary molar, additional relation to be noted is
1) Incisor relation
2) Canine relation
3) Midline relation
4) Premolar relation
Orthodontics Answer: 2
SOLUTION
If the edgewise bracket is not pressed completely on to a tooth on the mesial side while bonding, the side effect would be
1. intrusion
2. extrusion
3. rotation
4. breakage of bracket
Orthodontics
Answer: 3
we are applying force distally only..force vector will rotate the tooth distally
Facial profile of a typical mouth breather is
1) Long and wide
2) Short and wide
3) Long and narrow
4) Short and narrow
Orthodontics Answer: 3
SOLUTION
Altered respiratory pattern, such as breathing through the mouth rather than the nose, could change the posture of the
head, jaw, and tongue. This in turn could alter the equilibrium of pressures on the jaws and teeth and affect both jaw growth and tooth position.
In order to breathe through the mouth, it is necessary to lower the mandible and tongue, and extend (tip back) the head.
If these postural changes were maintained, face height would increase, and posterior teeth would super-erupt;
unless there was unusual vertical growth of the ramus, the mandible would rotate down and back, opening the bite
anteriorly and increasing overjet; and increased pressure from the stretched cheeks might cause a narrower maxillary dental arch.