Mixed Deck — All DMD Topics Flashcards

Anterior open bite malocclusion that develops during the mixed dentition is most commonly associated with which parafunctional habit?

Answer: Digit sucking (thumb/finger) or tongue thrusting

Digit sucking and tongue thrusting exert persistent forces on the dentition that tip the upper incisors labially, depress lower incisors, and prevent anterior vertical overlap, resulting in an open bite.

What is the role of salivary glands in the oral cavity?

Answer: To aid in digestion and lubrication

Salivary glands produce saliva, which plays several critical roles in the oral cavity. Saliva contains enzymes like amylase that begin the chemical breakdown of carbohydrates, initiating digestion. It also lubricates food, making it easier to chew and swallow, and helps maintain oral hygiene by washing away food particles and neutralizing acids.

Which orthodontic wire alloy exhibits the highest springback (range of action) and is most commonly used during the initial alignment phase of fixed appliance therapy?

Answer: Nickel-titanium (NiTi)

Nickel-titanium (NiTi) wires have the highest springback due to their superelastic or thermoelastic properties, delivering light, continuous forces ideal for initial leveling and alignment.

How can a dentist maintain professionalism in patient care?

Answer: By being honest, respectful, and upholding ethical standards

Professionalism in dentistry is built on trust and respect, which are fundamental to ethical patient care. Dentists maintain this by consistently demonstrating honesty in their diagnoses and treatment plans, showing respect for patient autonomy and concerns, and strictly adhering to ethical guidelines. These principles ensure patient safety, foster a positive doctor-patient relationship, and uphold the integrity of the profession.

What is the recommended fluoride varnish application schedule for high-caries-risk children under 6 years of age according to ADA guidelines?

Answer: Every 3–6 months

The ADA recommends fluoride varnish application every 3 to 6 months for children at elevated caries risk to maximize preventive benefit.

What is the role of the temporomandibular joint (TMJ)?

Answer: To enable jaw movement for chewing and speaking

The temporomandibular joint (TMJ) is a complex joint connecting the jawbone (mandible) to the skull. It acts like a sliding hinge, allowing for a wide range of jaw movements, including opening and closing the mouth, side-to-side motion, and forward/backward movement. These movements are essential for vital functions such as chewing, speaking, and swallowing.

What is the primary function of the incisors?

Answer: Cutting food

Incisors are the eight front teeth, four on the top and four on the bottom, characterized by their sharp, chisel-like edges. Their primary function is to bite into and cut food into smaller, manageable pieces. This initial mechanical breakdown is crucial for the subsequent stages of digestion.

A patient complains of a sharp pain on tooth #14, specifically upon releasing pressure after biting down on something hard. The pain is momentary and difficult to pinpoint. Probing depths are within normal limits, and the tooth responds normally to thermal pulp testing. Which diagnosis is most probable?

Answer: Cracked Tooth Syndrome

Cracked tooth syndrome is classically characterized by a sharp, fleeting pain upon biting and, more specifically, upon the release of biting pressure. This 'rebound pain' occurs as the fractured segments of the tooth move and then snap back together, stimulating fluid movement within the dentinal tubules and irritating the pulp. In early stages, probing depths and vitality tests are often normal.

A 25-year-old female patient presents for a restorative procedure. She reports an allergy to 'Novocain' from a past dental experience where she developed a rash. Which local anesthetic would be the safest to use for this patient?

Answer: Articaine

Novocain is the brand name for procaine, which is an ester-type local anesthetic. True allergic reactions to local anesthetics are rare, but when they occur, they are more common with the ester class due to the metabolite para-aminobenzoic acid (PABA). Articaine is an amide-type local anesthetic. Cross-allergenicity between ester and amide anesthetics is unlikely. Therefore, an amide anesthetic like articaine (or lidocaine, mepivacaine) would be a safe alternative. Benzocaine and tetracaine are also esters.

The Tweed analysis uses a triangle formed by three cephalometric measurements. Which set of angles comprises the Tweed triangle?

Answer: FMA, FMIA, IMPA

The Tweed triangle consists of FMA (Frankfort-mandibular plane angle), FMIA (Frankfort-mandibular incisor angle), and IMPA (incisor-mandibular plane angle), which together always sum to 180°.

A 10-year-old patient presents for an initial examination. Clinically, the teeth have a characteristic blue-gray opalescent hue. Radiographs reveal bulbous crowns with marked cervical constriction and near-complete obliteration of pulp chambers and root canals in both the primary and permanent dentitions. What is the most likely diagnosis?

Answer: Dentinogenesis Imperfecta

Dentinogenesis Imperfecta (DI) is a hereditary disorder affecting dentin formation. The clinical and radiographic findings of opalescent teeth, bulbous crowns, cervical constriction ('tulip shape'), and progressive obliteration of the pulp are pathognomonic for this condition. [6, 17, 20] Amelogenesis Imperfecta affects enamel, Regional Odontodysplasia is a localized 'ghost teeth' phenomenon, and Tricho-Dento-Osseous Syndrome involves other specific systemic features not described.

In orthodontic mechanics, 'anchorage' is best defined as:

Answer: Resistance to unwanted or reactive tooth movement

Anchorage refers to the resistance offered by teeth, bone, or extraoral structures to the reactive (unwanted) forces generated during orthodontic tooth movement.

Which bracket slot dimension is characteristic of the standard edgewise appliance and allows full three-dimensional control of tooth position including torque?

Answer: 0.022 × 0.028 inch slot

The standard edgewise bracket uses a 0.022 × 0.028 inch rectangular slot, which accommodates large rectangular wires that allow precise torque and tip control in three planes of space.

Which radiographic landmark appears as a radiopaque bow-shaped line above the roots of the maxillary posterior teeth on a periapical radiograph?

Answer: Floor of the maxillary sinus

The floor of the maxillary sinus appears as a radiopaque curved line that can overlie or be near the apices of the maxillary premolars and molars on periapical X-rays.

A 22-year-old systemically healthy female presents with severe, angular bone loss localized to the maxillary first molars and mandibular incisors, discovered on routine radiographs. Clinical examination reveals 7-8 mm probing depths in these areas, but surprisingly minimal plaque and calculus accumulation. What is the most likely diagnosis?

Answer: Localized Aggressive Periodontitis

Localized Aggressive Periodontitis (LAP) is characterized by rapid, severe attachment loss typically affecting a younger population (often around puberty), with a classic presentation involving the first molars and incisors. A key diagnostic feature is the inconsistency between the minimal amounts of plaque/calculus and the severity of periodontal destruction.

The Hyrax rapid palatal expander achieves skeletal expansion of the maxilla primarily through which mechanism?

Answer: Opening of the midpalatal suture to produce true skeletal widening

The Hyrax RPE opens the midpalatal suture through heavy orthopedic forces, producing true skeletal expansion of the maxillary arch — most effective before suture fusion in adolescence.

A trauma patient presents with mobility of the entire midface, including the zygomatic complex, resulting in a 'dish-face' deformity and craniofacial dysjunction. When the maxilla is grasped, the entire facial skeleton moves. This clinical presentation corresponds to which Le Fort fracture classification?

Answer: Le Fort III

A Le Fort III fracture, also known as craniofacial dysjunction, is the most severe type, involving a transverse fracture line that passes through the nasofrontal suture, maxillo-frontal suture, orbital wall, and zygomatic arch. This results in the complete separation of the facial bones from the cranial base, leading to the mobility of the entire face.

According to Angle's classification, which occlusal relationship is present when the mesiobuccal cusp of the maxillary first molar occludes in the buccal groove of the mandibular first molar?

Answer: Class I

Class I is defined by the mesiobuccal cusp of the upper first molar occluding in the buccal groove of the lower first molar, representing the ideal molar relationship.

A 28-year-old female patient desires a new crown on tooth #8 for esthetic reasons. She has a high smile line and is concerned about the potential for a dark line at the gingival margin. She has no metal allergies and no signs of bruxism. Which type of crown would be the most esthetic choice to address her specific concern?

Answer: All-ceramic crown

All-ceramic crowns, such as those made from lithium disilicate or feldspathic porcelain, offer superior esthetics because they are metal-free and can mimic the translucency and color of natural teeth. This eliminates the risk of a dark metal margin showing at the gumline, which is a common esthetic drawback of PFM crowns, especially if gingival recession occurs. While monolithic zirconia is strong, it is generally more opaque than other all-ceramic options and may not provide the highest level of esthetics for an anterior tooth with a high smile line.

A panoramic radiograph of a 22-year-old male reveals a well-defined, unilocular radiolucency surrounding the crown of an impacted mandibular third molar. The lesion is asymptomatic. Which of the following is the most probable diagnosis?

Answer: Dentigerous Cyst

A dentigerous (or follicular) cyst is a developmental odontogenic cyst that characteristically forms around the crown of an unerupted or impacted tooth. While ameloblastoma and odontogenic keratocyst can appear similarly and in the same location, the classic presentation described is most indicative of a dentigerous cyst. A radicular cyst is associated with a non-vital tooth.