بنك أسئلة الاستعاضة السنية والتركيبات

اقرأ أسئلة عيّنة بنك أسئلة الاستعاضة السنية والتركيبات

1. 1.Which structure is considered the primary stress-bearing area of the maxillary edentulous ridge?

   • أ.Horizontal portion of the hard palateإجابة صحيحة
   • ب.Incisive papilla
   • ج.Crest of the residual ridge
   • د.Maxillary tuberosity

   لماذا: The horizontal portion of the hard palate lateral to the midline is covered by firm, resilient mucosa well suited to withstand masticatory load. The crest of the maxillary ridge, being resorption-prone, is treated as a secondary stress-bearing area.

2. 2.The buccal shelf of the mandible is bounded laterally by which structure?

   • أ.Mylohyoid ridge
   • ب.External oblique ridgeإجابة صحيحة
   • ج.Genial tubercles
   • د.Retromylohyoid fossa

   لماذا: The buccal shelf extends from the crest of the ridge to the external oblique ridge and lies between the buccal frenum and the retromolar pad. It is oriented roughly at right angles to vertical occlusal forces, making it the primary stress-bearing area of the mandible.

3. 3.Which anatomical landmark forms the distolingual termination of the mandibular denture flange?

   • أ.Retromolar pad
   • ب.Masseteric notch
   • ج.Retromylohyoid fossaإجابة صحيحة
   • د.Sublingual fold

   لماذا: The retromylohyoid fossa lies posterior and lingual to the mylohyoid ridge and receives the distolingual flange of the mandibular denture. Proper extension into this space enhances the border seal and stability of the lower denture.

4. 4.The posterior palatal seal is placed just anterior to which anatomical structure or line?

   • أ.Junction of hard and soft palate only
   • ب.Hamular notch bilaterally only
   • ج.Fovea palatinae exactly
   • د.Vibrating lineإجابة صحيحة

   لماذا: The posterior palatal seal is placed on the soft tissue anterior to the vibrating line, extending between the two hamular notches. It compensates for polymerization shrinkage of the denture base and enhances the posterior border seal.

5. 5.Which of the following is a structure over thin, tightly bound mucosa that must be relieved in the maxillary denture?

   • أ.Median palatine rapheإجابة صحيحة
   • ب.Rugae area
   • ج.Buccal shelf
   • د.Maxillary tuberosity

   لماذا: The median palatine raphe covers the median palatine suture and is typically covered by thin, tightly bound mucosa over bone, requiring relief to avoid soreness. Together with the incisive papilla and any torus, it is treated as a relief area rather than a support area.

6. 6.The genial tubercles become prominent mandibular landmarks primarily as a result of what process?

   • أ.Trauma during extraction
   • ب.Advanced residual ridge resorptionإجابة صحيحة
   • ج.Congenital enlargement
   • د.Chronic infection

   لماذا: As the mandibular ridge resorbs over time, the genial tubercles (attachment for the genioglossus muscle) become relatively more prominent. Severe resorption may require relief of the denture base over these tubercles to prevent soreness.

7. 7.Which structure chiefly limits the height of the distobuccal flange of the maxillary denture?

   • أ.Buccinator
   • ب.Masseter
   • ج.Coronoid process of the mandibleإجابة صحيحة
   • د.Medial pterygoid

   لماذا: During wide opening and lateral movements, the coronoid process moves forward and can encroach on the distobuccal region of the maxillary denture. The flange in this area must be reduced to accommodate coronoid movement and prevent dislodgement.

8. 8.The primary purpose of border molding during final impression making is to:

   • أ.Record the crest of the ridge
   • ب.Increase vertical dimension
   • ج.Register centric relation
   • د.Establish the functional depth and width of the vestibuleإجابة صحيحة

   لماذا: Border molding uses functional or manipulated muscle movements to shape impression material at the borders, recording the physiologic form and extent of the sulcus. This produces properly extended flanges that maximize the peripheral seal without overextension.

9. 9.Modeling plastic impression compound is classified as which type of impression material?

   • أ.Thermoplasticإجابة صحيحة
   • ب.Elastic
   • ج.Chemically cured elastomer
   • د.Aqueous hydrocolloid

   لماذا: Impression compound is a thermoplastic (reversible on heating) material that softens with heat and hardens on cooling. It is commonly used for border molding and preliminary impressions of edentulous arches.

10. 10.Zinc oxide-eugenol impression paste is best described as a material that is:

    • أ.Highly elastic on set
    • ب.Mucostatic and rigid on setإجابة صحيحة
    • ج.Reversible thermoplastic
    • د.Hydrophobic and porous

    لماذا: Zinc oxide-eugenol paste is a rigid, mucostatic (minimal-pressure) material that records fine surface detail of the mucosa without displacing it. It is most suitable when a passive, non-pressure final impression is desired over a well-formed ridge.