4dd MCQs 325 Orthodontics I Prof. Mey Phoung 2019

Delayed extraction of deciduous teeth can lead to various issues such as malocclusion, crowding, impacted permanent teeth, and permanent teeth not being in the arch. This is because deciduous teeth play a crucial role in maintaining space and guiding the eruption of permanent teeth. When deciduous teeth are not extracted in a timely manner, it can disrupt the natural sequence of tooth eruption and result in misalignment, overcrowding, and impacted permanent teeth. Therefore, all of these issues are interrelated and can occur as a consequence of delayed extraction of deciduous teeth.

When the result of subtracting the total teeth width from the total arch length is a positive value, it indicates the presence of spacing. This means that there is extra space between the teeth, which can result in gaps or spaces between the teeth.

Every millimeter of incisor overjet reduction requires the space in the dental arch. Therefore, if we want to reduce the incisor overjet by 2 millimeters, it means that we need 2 millimeters of space in the dental arch to accommodate this reduction.

The correct answer is "All are related." This means that when the maxilla is retrusive and the mandible is normal, or when the maxilla is retrusive and the mandible is protrusive, or when the maxilla is normal and the mandible is protrusive, all of these conditions are related to the skeletal base. In other words, the position and relationship of the maxilla and mandible affect the skeletal structure of the face.

The correct answer is "All are related." This means that all of the options mentioned (intra-maxillary, inter-maxillary, and extra-oral anchorage) are types of anchorage used in orthodontic treatment.

The Frankfort Horizontal is a reference plane used in orthodontics and craniofacial analysis. It is constructed by joining two landmarks: the Porion, which is the highest point on the external auditory meatus, and the Orbital, which is the lowest point on the margin of the eye socket. This reference plane is important for analyzing the position of the skull and facial structures in relation to each other.

The correct answer is Nasion2. The fronto-nasal suture is a fibrous joint that connects the frontal bone to the nasal bones. The term "Nasion2" is likely a typographical error, as "nasion" refers to the point where the frontal bone and the nasal bones meet. Therefore, the correct answer is Nasion, not Nasion2.

The flush terminal plane is located distal to the Es. This means that the terminal plane of the teeth is in alignment with the distal surface of the Es tooth.

In Class II Division 1 malocclusion, the upper front teeth (anterior teeth) are protruded or stick out in relation to the lower front teeth. This protrusion can make the anterior teeth more susceptible to fractures, especially in children who may engage in activities that increase the risk of trauma to the mouth, such as sports or rough play. Therefore, children with Class II Division 1 malocclusion are more likely to experience anterior teeth fractures compared to those with other mixed dentition malocclusions.

The anterior point of the fronto-nasal suture is referred to as the N Point. The fronto-nasal suture is the junction between the frontal bone and the nasal bones. The N Point is an important landmark in orthodontics and craniofacial surgery as it is used to measure and analyze the position and growth of the maxilla (upper jaw) in relation to the skull.

The correct answer is B Point. The B Point is the deepest point on the concavity of the mandibular profile between the point of chin and the alveolar crest. This point is important in orthodontics and orthognathic surgery as it helps determine the position of the lower jaw.

The Mandibular plane (Mn) is represented by a line drawn through the points Me (Menton) and Go (Gonion). These two points are anatomical landmarks on the lower jaw. Me represents the most anterior point on the chin, while Go represents the most posterior point on the angle of the mandible. Drawing a line through these two points helps to determine the orientation and position of the mandible in relation to the skull. The other options mentioned (Me and Pog, Me and Po, Me and Ba) are unrelated and do not represent the Mandibular plane.

The correct answer is Springs and Screws. Active components are those that can generate and control energy within a system. Springs and screws are examples of active components as they can store and release energy, and their behavior can be controlled to perform specific functions.

The correct answer is "All are related." This means that all the options mentioned (palatally, buccally, in the arch) are related to the topic being discussed. The question is asking about the position of a canine tooth when it is impacted, and all the options listed are different possible positions for an impacted canine tooth. Therefore, the correct answer is that all of these options are related to the topic of canine impaction.

The factors that affect the choice of teeth for extraction are all related to one another. The position of the teeth plays a role in determining if extraction is necessary. The prognosis, or the expected outcome of the tooth, also influences the decision. Additionally, the amount of space required and the anchorage requirements are factors that need to be considered when choosing which teeth to extract. These factors are interconnected and should be taken into account collectively when making a decision about extraction.

The precise way to take an impression for orthodontic treatment is necessary because all the mentioned factors are related to the success and accuracy of the treatment. Checking the sulcus is important to assess the health of the gums and ensure proper fit of the orthodontic appliances. Checking the fraenum is crucial to identify any abnormalities or restrictions that may affect the treatment plan. Additionally, examining unerupted teeth helps in determining their position and alignment, which is essential for planning the orthodontic treatment effectively. Therefore, all the mentioned factors are interrelated and play a significant role in achieving optimal results in orthodontic treatment.

Trauma to deciduous teeth can cause dilacerations during the eruption of permanent central incisors. When deciduous teeth experience trauma, it can affect the development and eruption of the permanent teeth. This trauma can lead to abnormal positioning or angulation of the permanent teeth, resulting in dilacerations. Therefore, trauma to deciduous teeth is a possible cause of dilacerations during the eruption of permanent central incisors.

A Class II, Division 2 malocclusion is characterized by the retroclination (backward tilting) of the maxillary central incisors. This means that the upper front teeth are inclined towards the palate instead of being in an upright position. This condition can result in an overbite or deep bite, where the upper front teeth overlap the lower front teeth excessively. The other options listed (open bite, steep mandibular plane, mesiocclusion of permanent first molars) are not typically associated with Class II, Division 2 malocclusion.

The advantage of functional appliances is that they are related to reducing the time of treatment in fixed appliances, reducing anchorage requirements in fixed appliances, and improving large overjets and class II buccal segments in growing patients. This means that functional appliances can help in achieving these goals, making them beneficial in orthodontic treatment.

Supernumerary teeth are extra teeth that develop in addition to the normal set of teeth. These additional teeth can cause various issues, including delayed eruption of teeth, malocclusion (improper alignment of the teeth), and the formation of dentigerous cysts (fluid-filled sacs around the crown of an unerupted tooth). Therefore, all of these conditions are related to supernumerary teeth.

The correct answer is "Close median diastema and frenectomy." This treatment involves closing the gap between the two front teeth (median diastema) and performing a frenectomy to remove excess tissue from the upper labial frenum. By addressing both the diastema and the frenum, the patient's smile can be improved and any functional issues caused by the frenum can be resolved.

The lateral view cephalometric radiograph is the most frequently used in orthodontics because it provides a comprehensive view of the patient's facial profile and skeletal structure. This radiograph allows orthodontists to assess the position and alignment of the teeth, as well as the relationship between the upper and lower jaws. It is an essential tool for diagnosing and planning orthodontic treatment. The postero-anterior and lateral oblique views may also be used in specific cases, but they are not as commonly used as the lateral view.

The Frankfort Horizontal is a reference plane in craniofacial analysis that is constructed by joining the Porion (the highest point of the external auditory meatus) and the Orbitale (the lowest point on the lower margin of the eye socket). This plane is used to assess the position of the maxilla and mandible in relation to the skull.

A Class II, Division 2 malocclusion is characterized by the lingual inclination of the maxillary central incisors. This means that the upper front teeth tilt towards the tongue. This is typically seen in individuals with a deep overbite and a retruded lower jaw. The other options, such as open bite, steep mandibular plane, and mesiocclusion of permanent first molars, are not typically associated with Class II, Division 2 malocclusion.

The Franfort plane (FP) is a reference line used in cephalometric analysis to measure the position and orientation of the skull. It is defined by a line connecting two anatomical landmarks: Po (porion) and Or (orbitale). Porion is the highest point of the external auditory meatus, while orbitale is the lowest point on the lower rim of the eye socket. Therefore, the correct answer is Po and Or.

The function of a labial bow is to retract the upper incisors. This means that it is used to move the upper front teeth backwards towards the palate. This can be done to correct crowding or to create space for other dental procedures. The labial bow applies pressure on the teeth, causing them to move in the desired direction.

The correct answer is that all of the options are related. This suggests that transposition of the teeth can occur in various positions, such as the permanent lateral incisor in the canine position, the permanent canine in the lateral position, the permanent premolar in the canine position, and the permanent canine in the premolar position. Transposition refers to the abnormal placement of teeth, where they switch positions with other teeth. Therefore, all of the options listed in the question are examples of transposition.

When the result of subtracting the total teeth width from the total arch length is a negative value, it indicates the presence of crowding. Crowding refers to a condition where there is not enough space in the dental arch to accommodate all the teeth properly. This can result in teeth being misaligned or overlapping each other. Therefore, the negative value suggests that there is not enough space for the teeth, indicating the presence of crowding.

In orthodontic treatment, wearing a removable appliance combined with a fixed appliance is necessary to reinforce anchorage. The fixed appliance, such as braces, provides the necessary force to move the teeth into the desired position. However, this force can sometimes cause unwanted movement of other teeth. By using a removable appliance, additional support is provided to anchor the teeth that should not move, ensuring that only the desired teeth are being adjusted. This combination of appliances allows for more effective and efficient orthodontic treatment.

The correct answer is "A flus terminal plane." A flus terminal plane refers to a line that drops perpendicular at the distal surface of upper and lower E's. This line represents the alignment of the terminal ends of the upper and lower teeth. The other options (facial plane, lee way space, occlusal plane) are unrelated and do not describe the specific line mentioned in the question.

When making the extraction decision for the upper second permanent molar, it is important to check all of the mentioned factors: the presence and condition of the upper third molar, the degree of crowding in the mouth, and the distance available for distalization. These factors are all interrelated and can influence the decision to extract the upper second permanent molar.

When the overjet (the horizontal distance between the upper and lower incisors) is greater than 9mm, there is a high risk of trauma to the upper central incisors. This is because a larger overjet increases the likelihood of the upper incisors coming into contact with an object or surface, leading to potential injury or trauma.

The space analysis of Tanaka and Johnston prediction value is based on the eruption of specific teeth in the mixed dentition. In this analysis, the eruption of the lateral incisors, central incisors, and permanent first molars are all considered as factors to predict the amount of space available for the eruption of the permanent canines and premolars. Therefore, all of these factors are related to the space analysis.

To achieve patient compliance, it is important for the patient to wear the functional appliance regularly. Wearing the appliance for at least 14 hours a day ensures that it is being used consistently and for a sufficient amount of time to achieve the desired results. Wearing the appliance for a shorter duration may not be effective, while wearing it for longer durations may cause discomfort or other issues. Therefore, wearing the functional appliance for 14 hours a day strikes a balance between effectiveness and patient comfort.

Functional appliances can help accelerate growth when there is a growth spurt. Growth spurts are periods of rapid growth during adolescence when the body undergoes significant changes. Functional appliances, such as braces or orthodontic devices, can be used during this time to guide the growth and development of the jaws and facial structures. By applying forces to the teeth and jaws, these appliances can help stimulate bone growth and correct any discrepancies in the growth pattern. This can lead to improved alignment of the teeth and a more harmonious facial profile.

The correct answer is "Po Point." The bony external auditory meatus is a part of the ear canal. The Po Point refers to the posterior superior point of the bony external auditory meatus, which is the highest point of this structure.

The Pog Point is the most anterior point of the bony chin. It is a reference point used in orthodontics and craniofacial analysis to measure and analyze the position of the chin and its relationship to other facial structures.

Springs are a type of active component used in various mechanical and electrical systems. They are designed to store and release mechanical energy, making them suitable for applications such as shock absorption, suspension systems, and electrical contacts. Springs can be found in a wide range of devices, including watches, cars, and industrial machinery. They are an essential component in many systems, providing flexibility and resilience to ensure proper functioning.

The correct answer is "All are related." This means that all the mentioned types of springs (Z spring, Buccal canine retractor, and T spring) are connected or associated in some way. It implies that they have similarities or are used for similar purposes in the context of removable appliances.

The correct answer is that all of the options listed are related. This means that the function of the baseplate for a removable appliance includes preventing unwanted drift of the teeth, supporting the wire and screw, contributing to anchorage, and protecting the palatal spring. These functions are all interconnected and work together to ensure the effectiveness and stability of the removable appliance.

Early extraction of the all second deciduous molars may lead to the tendency of all 1st permanent molars to move mesially. This means that the first permanent molars, which are the first permanent teeth to erupt in the mouth, may shift towards the front of the mouth. This can cause misalignment of the teeth and affect the overall bite and alignment of the jaws.

The components for removable appliance are ARAB, which stands for Active components, Retentive components, Anchorage, and Base plate. Active components refer to the parts of the appliance that actively move or adjust the teeth, such as springs or screws. Retentive components are responsible for keeping the appliance in place, such as clasps or wires. Anchorage refers to the support or stability provided by the surrounding teeth or bone. Lastly, the base plate is the part of the appliance that rests on the gums or palate.

The correct answer is 0.7 mm. This suggests that Adams used a wire with a diameter of 0.7 mm for claps on the first molar for retention.

When the E is extracted after 6 has erupted, the premature loss of the deciduous teeth can cause the 6 (permanent tooth) to tilt mesially. This means that the 6 will lean towards the front of the mouth. This is a common occurrence when there is a space created due to the extraction of a deciduous tooth before the permanent tooth is ready to come in.

A space maintainer is used when a deciduous tooth is lost prematurely. This is because the deciduous tooth acts as a placeholder for the permanent tooth that will eventually replace it. If the deciduous tooth is lost too early, a space maintainer can be used to prevent the adjacent teeth from shifting into the empty space and causing alignment issues for the permanent tooth. Therefore, the correct answer is "The E is lost prematurely."

The correct answer states that the upper canine should overlap the mesial aspect of the lateral root but not extend higher than the apical third of the root. This is because a proper alignment of the upper canine requires it to be positioned in such a way that it does not interfere with the adjacent teeth and their roots. If the canine overlaps too much or extends too high, it can cause damage to the adjacent teeth and hinder proper alignment. Therefore, the correct alignment of the upper canine is important for a successful prognosis.

The answer is "Position of tooth away from normal." This means that the tooth is not in its usual or expected position. It could be located in a different area of the mouth or in an abnormal orientation. This term is used to describe teeth that are not properly aligned or positioned within the dental arch.

The fronto-nasal suture is the junction between the frontal bone and the nasal bones. The term "nasion" refers to the point where the fronto-nasal suture meets the midline of the skull. It is an important landmark used in anthropological and anatomical studies to measure the position of the nasal bones and the overall shape of the skull. The other options, such as frontal, sella, and basion, are not directly related to the fronto-nasal suture.

Headgear is a type of extra-oral traction that is often used in combination with fixed appliance treatment. It involves the use of a strap or harness that is attached to the patient's head and connected to the braces or appliances in their mouth. The purpose of headgear is to apply gentle pressure to the teeth and jaw, helping to correct alignment issues and guide the growth of the facial bones. This type of traction is commonly used in orthodontic treatment to address overbites and underbites.

The correct answer is Pogonion, Menton, Gonion, Point B, Ii. These are all mandibular landmarks that are commonly used in orthodontics and craniofacial analysis. Pogonion refers to the most anterior point on the chin, Menton is the most inferior point of the mandible, Gonion is the angle formed by the junction of the posterior border of the mandible, Point B is a reference point on the mandible used in cephalometric analysis, and Ii is the incisal edge of the mandibular central incisor.

The correct answer is "Skeletal is class III base." This means that the skeletal structure of the face is positioned in such a way that the lower jaw is protruding forward in relation to the upper jaw. This can result in a concave appearance when viewed in profile.

The correct answer is that all of the options listed are related to preserving the anchorage for a removable appliance. Contacting the baseplate with other teeth not being moved helps to stabilize the appliance and prevent unwanted movement. Placing clasps or bows on teeth that are not being moved also helps to provide additional support and stability. Contacting the baseplate with the vertical part of the palate in the areas of the rugae helps to distribute the forces evenly and prevent displacement of the appliance. Therefore, all of these actions are important in preserving the anchorage for a removable appliance.

Upper incisor inclination of 140 degrees means that the upper incisors are proclined. Proclined refers to the forward or outward inclination of the teeth. In this case, the upper incisors are tilted forward or protruding outwards from their normal position.

The correct answer is that all the anomalies in the position of teeth during eruption are related. This means that ectopic eruption, transposition, and impaction are all interconnected and can occur simultaneously or in combination with each other. These anomalies refer to the abnormal positioning of teeth during the process of eruption, where they may be misplaced, rotated, or impacted. Therefore, it can be concluded that these anomalies are not unrelated occurrences but rather part of a common issue in the positioning of teeth during eruption.

The given answer is correct because it states that a ¼ turn corresponds to a screw expansion of 0.25mm. This implies that for every ¼ turn of the screw, the expansion of the screw is 0.25mm.

The most frequently used cephalometric view in orthodontics is the lateral view. This view provides a side profile of the patient's head and allows orthodontists to analyze the relationship between the teeth, jaws, and facial structures. It is commonly used for diagnosing and planning orthodontic treatment. The postero-anterior view provides a front-facing view of the head, while the lateral oblique view provides a diagonal view. Both of these views may also be used in orthodontics, but the lateral view is the most commonly used.

In cephalometric analysis, the angle ANB is used to measure the relationship between the position of the maxilla (A point) and the mandible (B point). In patients with severe Class II malocclusion, the mandible is positioned further back than normal, causing the angle ANB to be greater than the norm. This indicates an excessive overjet or protrusion of the upper jaw relative to the lower jaw.

The inter-incisal angle is a measurement that is constructed by the axis of the upper incisor to the lower incisor. This angle helps to determine the alignment and positioning of the upper and lower incisors in relation to each other. By measuring this angle, dentists can assess the occlusion and bite of a patient, which can be important for diagnosing and treating various dental conditions.

During the ugly duckling stage, the most common cause of median diastema (a gap between the front teeth) is the eruption of the permanent maxillary incisors. These permanent teeth start to grow in around the age of 8 to 9 years. This can cause the primary incisors to become loose and create a gap between them. Therefore, the correct answer is 8 to 9 years of age.

The correct answer implies that normal occlusion refers to a situation where all the given factors are related. This means that the molars have a class I relationship according to Angle classification, the incisors have a class I relationship according to British standards incisor classification, and there is no rotation present. These factors collectively define normal occlusion.

Anodontia refers to the condition where a person fails to develop all of their teeth. This means that they may be missing some or all of their teeth, which can significantly impact their ability to eat, speak, and maintain proper oral health. Anodontia can be caused by genetic factors, certain medical conditions, or environmental factors. Treatment options for anodontia may include dental implants, dentures, or other dental prosthetics to restore function and aesthetics.

The correct answer is 0.5 mm because it is the specific size of wire recommended for Z spring. The other options, 0.7 mm and 0.9 mm, are not the appropriate sizes for the Z spring. Additionally, the options "All are related" and "All unrelated" do not provide any specific information about the size of wire for Z spring.

The retentive components of an appliance are designed to keep the appliance in position. These components provide stability and prevent the appliance from moving or shifting. They are essential in maintaining the proper alignment of the teeth and ensuring that the appliance functions effectively. Without the retentive components, the appliance would not be able to fulfill its purpose of keeping the teeth in position.

Increasing the millimeter of incisor overjet creates space in the dental arch. Therefore, for every millimeter of incisor overjet increase, 2 mm of space is created in the dental arch.

A functional appliance would be the appropriate management for this patient. A functional appliance can help correct the class II incisor relationship by promoting forward growth of the mandible, which is retrusive in this case. It can also help reduce the overjet of 11 mm by guiding the growth and development of the jaws. Additionally, a functional appliance can be used to align the teeth and improve the overall occlusion. Therefore, a functional appliance is the most suitable treatment option for this patient.

When the second premolars are absent, it is important to consider all aspects related to the situation. This includes checking the root formation of the adjacent teeth (E), as well as assessing the crown form of those teeth. Additionally, it may be necessary to make a crown on the adjacent teeth to compensate for the missing premolars. Finally, adding composite material to the area can help improve the aesthetics and functionality of the affected area.

Primate spacing refers to the natural gaps that occur between the primary (deciduous) canines and molars in the human dentition. These spaces allow for the eruption of the larger permanent teeth. This term is used to describe the spacing distal to the lower deciduous canines and mesial to the upper deciduous canine. The other options, Lee way space, Flus terminal plane, and Free way space, are unrelated to this specific spacing pattern.

Excessive lower face height can cause an anterior open bite. This occurs when there is a vertical gap between the upper and lower front teeth, preventing them from making contact. Excessive lower face height can lead to an imbalance in the forces exerted on the teeth, resulting in the open bite.

The correct answer is "posteriorly of the cingulum plateau of the upper incisors." This means that the edges of the lower incisors occlude or come into contact with the back part of the cingulum plateau, which is the rounded area on the lingual (back) surface of the upper incisors. This relationship is classified as Class II, indicating that the lower incisors are positioned more towards the back compared to the upper incisors.

The correct answer is that mandible growth is longer than the maxilla. During the growth and development of a child, the mandible (lower jaw) tends to grow at a faster rate compared to the maxilla (upper jaw). This difference in growth rates can lead to changes in the occlusion (bite) of the child, such as the molar class II becoming class I as stated in the question.

Thumb sucking can cause malocclusion, which is misalignment of the teeth and jaws. In this case, the upper arch is narrowed, meaning it is not wide enough to accommodate all the teeth properly. Additionally, there is a unilateral crossbite in the posterior segment, which means that the upper teeth on one side are biting inside the lower teeth. This can lead to an uneven bite and difficulty in chewing. The overjet, which is the horizontal distance between the upper and lower front teeth, is decreased or "minus." The upper incisor teeth are also retroclined, meaning they are tilted towards the inside of the mouth. Finally, the overbite is deep and complete, indicating that the upper front teeth excessively overlap the lower front teeth.

Tongue thrust refers to the habit of pushing the tongue against or between the teeth during swallowing or at rest. This can lead to an overbite or anterior open bite, where the upper front teeth protrude or do not meet the lower front teeth properly. Therefore, the effective treatment of tongue thrust can result in a reduction of overbite or anterior open bite, improving the alignment of the teeth.

The correct answer is "All are related". This means that all the options mentioned in the question are connected or relevant to each other in some way. It implies that exposing a canine when it is impacted can be achieved through any of the methods mentioned, such as closing the exposed area, opening the exposed area, or using a gold chain.

When space requirement is moderate or severe, the first permanent premolars are often chosen to be extracted. This is because these teeth are located towards the back of the mouth and their removal can create enough space for other teeth to properly align. Extracting the first permanent premolars can help address issues such as overcrowding and misalignment of the teeth.

The term "midline coincidence" refers to the alignment of the upper and lower midlines in the middle. This means that both the upper and lower midlines are perfectly aligned and centered in the middle of the face. This alignment is considered ideal and aesthetically pleasing.

The model base is kept as a record for the patient in orthodontic treatment because all the mentioned reasons are related to each other. By keeping the model base, it becomes easier to maintain the aesthetic appearance of the patient's teeth and keep them in the desired position. It also helps in understanding the relationship of occlusion, which is the alignment and contact between the upper and lower teeth. Additionally, the model base makes it easier to count the number of teeth accurately. Overall, keeping the model base serves multiple purposes in orthodontic treatment.

When a deciduous tooth is lost prematurely, it can lead to the shifting of adjacent teeth into the empty space, causing misalignment and crowding of permanent teeth. To prevent this, a space maintainer can be used. This device helps to keep the space open until the permanent tooth erupts, ensuring proper alignment and preventing the need for orthodontic treatment in the future.