Dental Decks

Mamelons present in one of following ? following is the most likely explanation for this finding? Posterior crossbite Anterior crossbite Variation of normal Anterior open bite < Nocturnal bruxism Question 3 Explanation: The correct answer is D. Mamelons are small enamel tubercles on the incisal edges of anterior teeth formed from the three facial developmental lobes. They normally wear away when the tooth comes into functional contact with its opposing tooth. In an anterior open bite situation, there is no contact between the maxillary and mandibular anterior teeth. The age of the patient suggests that if the teeth were in contact, the mamelons would have been worn away. Answer A is incorrect. In a posterior crossbite, the anterior teeth would most likely remain in function during excursive movements, and the mamelons would have worn away. Answer B is incorrect. In an anterior crossbite, the anterior teeth would most likely remain in function during excursive movements, and the mamelons would have worn away. Answer C is incorrect. The presence of mamelons is considered normal only when they are present on newly erupted teeth that haven’t yet contacted their antagonists. Answer E in incorrect. Grinding of the teeth at night would lead to attrition, flattening the incisal edges or cusp tips, thus wearing mamelons away. Question 4 Which of the following teeth is most likely to be congenitally absent? Maxillary lateral incisor < Maxillary canine Mandibular canine Mandibular 1st premolar Mandibular 2nd premolar Question 4 Explanation: The correct answer is A. The most frequently congenitally missing teeth: 3rd molars > Maxillary laterals > Mandibular 2nd premolars

The facial height-of-contour of the maxillary 2nd premolar is in what segment of the crown? Incisal 3rd Junction of the incisal and middle 3rds Middle 3rd Junction of the middle and cervical 3rds Cervical 3rd < Question 1 Explanation: The correct answer is E. Remember that the buccal/facial HOC of all permanent teeth is located in the cervical 3rd of the crown. The lingual HOC of all anterior teeth is also located in the cervical 3rd (at the cingulum). Answer C is incorrect. The lingual HOC of all posterior teeth (premolars and molars) is located in the middle 3rd of the crown.

Which muscle inserts in the articular disc and condylar neck? Masseter Medial pterygoid Lateral pterygoid < Temporalis Question 2 Explanation: The correct answer is C. The superior fibers of the lateral pterygoid originate at the roof of the infratemporal fossa, and insert in the articular capsule and disc. Its inferior fibers originate on the lateral side of the lateral pterygoid plate, and insert on the anterior condylar neck. Functions of the lateral pterygoid muscle include mandibular protrusion, depression, and contralateral excursion. Answer A is incorrect. The superior fibers of the lateral pterygoid originate at the roof of the infratemporal fossa, and insert in the articular capsule and disc. Its inferior fibers originate on the lateral side of the lateral pterygoid plate, and insert on the anterior condylar neck. Functions of the lateral pterygoid muscle include mandibular protrusion, depression, and contralateral excursion. Answer B is incorrect. The medial pterygoid originates at the medial side of the lateral pterygoid plate, and inserts on the medial side of the mandibular angle. Functions of the medial pterygoid muscle include mandibular elevation, protrusion, and contralateral excursion. Answer D is incorrect. The temporalis originates at the lower temporal line, temporal fossa, and temporal fascia, and inserts on the medial coronoid process and anterior ramus. Functions of the temporalis muscle include mandibular elevation, retrusion, and ipsilateral excursion.

Which of the following is the term for a supernumerary tooth in the maxillary anterior region? Mesiodens < Distodens Dens-in-dente Paramolar Talon cusp Question 3 Explanation: The correct answer is A. A mesiodens is a small supernumerary tooth that typically forms between maxillary central incisors. It has a cone-shaped crown with a short root, and may remain unerupted. Answer B is incorrect. A supernumerary 4th molar is often called a distodens, or distomolar. Answer C is incorrect. Dens-in-dente (toothwithin- a-tooth) is a deep surface invagination of the crown or root that is lined by enamel. In order of decreasing frequency, the permanent teeth most commonly affected are the following: Lateral incisors > Central incisors > Premolars > Canines > Molars. Answer D is incorrect. A supernumerary tooth situated lingually or buccally to a molar tooth is termed a paramolar. Answer E is incorrect. A talon cusp (dens evaginatus of an anterior tooth) is a welldelineated additional cusp (not an additional tooth) that is located on the surface of an anterior tooth. These cusps occur most commonly on maxillary lateral and central incisors, projecting from the lingual surface, and forming a three-pronged pattern resembling an eagle’s talon.

The horizontal distance between the labioincisal surfaces of mandibular incisors and the linguoincisal surfaces of maxillary teeth is referred to as overjet. overbite. openbite. < crossbite. Question 4 Explanation: The correct answer is A. Overjet is defined as horizontal overlap of the incisors, normally 2-3 mm. Answer B is incorrect. Overbite is defined as the vertical overlap of the incisors, normally 1-2 mm. Answer C is incorrect. There is no vertical overlap of the incisors in an openbite. Anterior openbite can result, for example, from a persistent thumb-sucking habit. Answer D is incorrect. Crossbite is a reversed horizontal overlap relationship of the teeth. If the lower incisors are anterior to the upper incisors in centric occlusion, the condition is called anterior crossbite or

reverse overjet. Posterior crossbite exists when the maxillary posterior teeth are lingually positioned relative to the mandibular teeth in centric occlusion. How many teeth contact both anterior and posterior segments of the opposing arch in ideal intercuspation? 0 2 4< 6 8 Question 5 Explanation: The correct answer is C. The maxillary canines contact mandibular canines (anterior segment) and mandibular 1st premolars (posterior segment). Likewise, the mandibular 1st premolar contacts the opposing maxillary canine (anterior) and 1st premolar (posterior). Thus, 2 maxillary canines + 2 mandibular 1st premolars = 4 total teeth. Remember: Maxillary teeth contact their opposing counterpart and the tooth distal to it. Mandibular teeth contact their opposing counterpart and the tooth mesial to it. A cervical ridge is found on the facial surface of how many primary teeth? 4 8 12 16 20 < Question 6 Explanation: The correct answer is E. The cervical ridge runs mesiodistally in the cervical 3rd of the buccal surface of all primary teeth (as well as all permanent molars). The cervical ridge is prominent in primary anterior teeth, and is best seen when viewed from the proximal. The cervical ridge of primary molars is most prominent on the mesial-facial aspect.