Dentosphere : World of Dentistry

 # Simple retraction of maxillary incisors using maxillary molars as anchorage is an example of:  (PGCEE MDS 2025) a) Simple anchorage  b) Reciprocal anchorage c) Stationary anchorage  d) Intermaxillary anchorage The correct answer is: c) Stationary anchorage Explanation: Stationary anchorage refers to a type of anchorage where the resistance to unwanted tooth movement is achieved by using teeth that undergo minimal movement, usually due to bodily movement rather than tipping. In simple retraction of maxillary incisors using maxillary molars as anchorage , the molars provide resistance while the incisors move posteriorly. The molars remain relatively stable, which characterizes stationary anchorage . Other types of anchorage: Simple anchorage – Resistance to movement provided by the PDL of the anchoring teeth. Reciprocal anchorage – Two equal and opposite forces are applied, leading to movement of both units (e.g., space closure between two adjacent teeth). Inter...

 # Serial extractions are indicated when there is - a) No skeletal discrepancy with dental crowding > 10 mm b) No skeletal discrepancy with dental crowding between 5 - 7 mm. c) Skeletal discrepancy >5° d) Skeletal discrepancy >10° with dental crowding < 5mm The correct answer is A. No skeletal discrepancy with dental crowding > 10 mm  Serial extraction is indicated in cases of severe dental crowding. For this reason, it is best used when no skeletal problem exists, and the space discrepancy is large i.e., >10 mm per arch. If the crowding is severe, little space will remain after the teeth are aligned, which means there will be little tipping and uncontrolled movement of the adjacent teeth into the extraction sites. If the initial space discrepancy is smaller, more residual space must be anticipated.

 # The commonest teeth involved in transposition are: a) Maxillary central incisor and lateral incisor b) Maxillary canine and first premolar c) Maxillary 1st premolar and 2nd premolar d) Maxillary canine and Lateral incisor The correct answer is: b) Maxillary canine and first premolar Explanation: Tooth transposition is a rare developmental anomaly where two adjacent teeth exchange their positions within the dental arch. The most commonly involved teeth in transposition are the maxillary canine and first premolar . This occurs due to disturbances in tooth eruption patterns, genetics, or space constraints in the dental arch. Other less common transpositions include: Maxillary canine and lateral incisor (less frequent but still observed) Mandibular canine and lateral incisor (rare)

 # The free gingival groove is most commonly associated with which tooth?  a) Maxillary canine  b) Mandibular incisor  c) Maxillary first molar  d) Mandibular premolar The correct answer is: b) Mandibular incisor The free gingival groove is a shallow linear depression that demarcates the free gingiva from the attached gingiva. It is more prominent in some individuals and may not always be present. However, when it is visible, it is most commonly associated with the mandibular incisors due to their relatively thin and well-defined gingival anatomy.  This aligns with standard dental textbooks like  Carranza’s Clinical Periodontology , which highlights the mandibular incisors as a common site for the free gingival groove.

 # Well aligned deciduous dentition is an indication of: A. Potential crowding B. Disto occlusion C. Mesio occlusion D. Well aligned permanent teeth The correct answer is: A. Potential crowding Explanation: Well-aligned deciduous dentition (primary teeth) with little to no spacing  is often a predictor of  potential crowding  in the permanent dentition. Primary teeth are smaller than permanent teeth, and deciduous arches typically exhibit natural spacing ("primate spaces") to accommodate the larger permanent successors. If primary teeth are tightly aligned, it suggests insufficient space for the eruption of larger permanent teeth, increasing the risk of crowding. D. Well-aligned permanent teeth  is incorrect because spaced (not tightly aligned) primary teeth are actually a better indicator of sufficient arch space for proper alignment of permanent teeth. B. Disto-occlusion  and  C. Mesio-occlusion  refer to malocclusions (Class II and Class III bi...

 # The palate is considered the most appropriate insertion site for miniscrews supporting an intraoral distalizer because it: a) is free of dental roots and other anatomical structures b) does not create a force vector passing coronally to the maxillary arch’s center of resistance c) takes advantage of bicortical anchorage d) all of the above The correct answer is D.  All of the above Explanation: The palate is an ideal site for miniscrew-supported intraoral distalizers because of the following advantages: Free of dental roots and other anatomical structures (Option a) The mid-palatal region is a safe zone with minimal risk of damaging dental roots or vital structures, making it ideal for miniscrew placement. Does not create a force vector passing coronally to the maxillary arch’s center of resistance (Option b) Placing miniscrews in the palate helps direct force closer to the center of resistance of the maxillary arch , reducing unwanted tipping or extrusion effects. Takes ...

 # Intraoral Class II distalizers have the major disadvantage of: a) the need for patient compliance b) a force vector passing coronally to the maxillary arch’s center of resistance c) anterior anchorage loss d) an inability to be used simultaneously with multibracket appliances The correct answer is: c) Anterior anchorage loss Explanation: Intraoral Class II distalizers, such as the Pendulum appliance, Distal Jet, or Forsus, rely on posterior force application to move the maxillary molars distally. However, a major drawback is anterior anchorage loss, meaning: As the maxillary molars move distally, the anterior teeth tend to drift forward, leading to proclination of the incisors. This can compromise the correction of a Class II malocclusion if not properly controlled with anchorage reinforcement. Why not the other options? (a) The need for patient compliance → Not true for most fixed distalizers (e.g., Pendulum, Distal Jet), but true for removable appliances like elastics or headg...

 # The Invisalign Palatal expander is directly printed from: a) polyamide-12 b) TC-85 c) polymethyl methacrylate d) thermoplastic polyurethane The correct answer is A. Polyamide-12. The Invisalign Palatal Expander (IPE) is 3D-printed directly from Polyamide-12 (PA-12) , a biocompatible and durable nylon-based material. This material is widely used in medical applications due to its strength, flexibility, and resistance to wear. PA-12 allows for precise and customized expansion while maintaining patient comfort.

  # The Invisalign Palatal Expander (IPE) is designed to expand the dentition in increments of: a) 0.1mm b) 0.25mm c) 0.5mm d) 1mm The correct answer is B. 0.25 mm. The Invisalign Palatal Expander (IPE) uses a series of custom-designed, 3D-printed expansion trays to gradually widen the upper arch. It expands the dentition in controlled increments of 0.25mm per adjustment, ensuring a more comfortable and predictable expansion compared to traditional rapid palatal expanders (RPEs).

 # Following are "essential diagnostic criteria" according to Graber except: a) Case history b) Facial photographs c) Periapical x-rays d) Lateral cephalograms The correct answer is: d) Lateral cephalograms Graber's essential diagnostic criteria for orthodontic diagnosis typically include case history, facial photographs, and periapical x-rays. Lateral cephalograms, while useful for orthodontic analysis, are not considered part of the essential diagnostic criteria according to Graber.