The primary function of posterior palatal seal is to:

 # The primary function of posterior palatal seal is to:

A. Retention of upper denture by making a complete seal

B. Aid in insertion and removal of the upper denture

C. Achieve balanced occlusion

D. Retention of lower denture

The correct answer is A. Retention of upper denture by making a complete seal.

The primary purpose of PPS is the retention of the maxillary denture. PPS creates a partial vacuum beneath the maxillary denture. This partial vacuum is activated only when horizontal or tipping forces are directed against the denture base. The duration of this vacuum is small and so little or no irreversible alterations to the underlying mucosa will take place.

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Face bow is used to record:

 # Face bow is used to record:

A. Orientation relation

B. Centric relation

C. Eccentric relation

D. Vertical jaw relation

The correct answer is A. Orientation relation.

The maxillary cast is attached to the articulator using the orientation jaw relation records. The procedure of transferring the orientation relation to the articulator is called face-bow transfer.

Orientation jaw relation is defined as: “the jaw relation when the mandible is kept in its most posterior position, it can rotate in the sagittal plane around an imaginary transverse axis passing through or near the condyles”—GPT.

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Fixed factor according to Hanau is:

 # Fixed factor according to Hanau is:

A. Orientation of occlusal plane

B. Condylar guidance

C. Incisal guidance

D. Compensating curve

The correct answer is B. Condylar guidance.

Increase in the condylar guidance will increase the jaw separation during protrusion. This factor

of balanced occlusion cannot be modified. All the other four factors of occlusion should be modified to compensate the effects of this factor. In patients with a steep condylar guidance, the incisal guidance should be decreased to reduce the amount of jaw separation produced during protrusion and vice versa. But it should be remembered that the incisal guidance cannot be made very steep because it has its own ill effects.

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A complete or partial removable denture supported by retained roots is known as:

 # A complete or partial removable denture supported by retained roots is known as:

A. Conventional immediate denture

B. Transitional immediate denture

C. Cast partial denture

D. Over dentures

The correct answer is D. Overdenture.

Overdentures are defined as, 'a dental prosthesis that replaces the lost or missing natural dentition and associated structures of the maxilla and/or mandible and receives partial support and stability from one or more modified natural teeth'. 

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An anterior tooth bounded edentulous area which crosses the midline:

 # An anterior tooth bounded edentulous area which crosses the midline:

A. Class I

B. Class III

C. Class IV

D. Class IX

The correct answer is C. Class IV.

Class IV Kennedy classification is a single but bilateral (crossing the midline) edentulous area located anterior to the remaining natural teeth.

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Which of these muscles may affect the borders of mandibular complete denture?

 # Which of these muscles may affect the borders of mandibular complete denture?

A. Mentalis

B. Lateral pterygoid

C. Orbicularis oris

D. Levator angularis

The correct answer is A. Mentalis.

The labial vestibule extends from the labial frenum to the buccal frenum. The mucolabial fold extends from the inner aspect of the lip to the mandible. The mentalis muscle inserts very close to the crest of the ridge in this area and limits the border extension in length and width.

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The minimal occlusal thickness of amalgam restoration for appropriate resistance to fracture is:

# The minimal occlusal thickness of amalgam restoration for appropriate resistance to fracture is:

A. 0.5 mm

B. 0.8 mm

C. 1.5 mm

D. 2.5 mm

The correct answer is C. 1.5 mm.

The relatively horizontal pulpal and gingival walls, prepared perpendicular to the tooth’s long axis, help the restoration resist occlusal forces and limit the likelihood of tooth fracture from wedging effects caused by opposing cusps. It may be necessary to reduce cusps that no longer have sufficient dentin support and cover (or envelope) them with an adequate thickness of restorative material in order to provide resistance to fracture of the tooth and/or the restorative material. Preparation design must allow for adequate thickness of polycrystalline restorative materials to ensure adequate primary resistance to restoration fracture. he minimal occlusal thickness, for appropriate resistance to fracture, of amalgam is 1.5 to 2 mm and glass-ceramic is 2 mm. Polymeric restorative materials (e.g., composite resins) have no minimal thickness.

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