A denture that will not stay put

Correct answer: C. An anterior flabby ridge with localised bone loss

• A. Combination syndrome tends to produce an increase in interarch space anteriorly as bone resorbs, not a loss of it.
• B. Resorption in this syndrome is characteristically localised to the anterior maxilla, which is precisely what makes the pattern recognisable.
• C. Correct. This is combination syndrome. Natural mandibular anterior teeth concentrate occlusal load on the anterior maxilla, so the bone there resorbs and is replaced by displaceable fibrous tissue, while the posterior maxilla is relatively spared. The rest of the syndrome includes tuberosity overgrowth, papillary hyperplasia of the palate, extrusion of the mandibular anterior teeth and loss of posterior mandibular bone.
• D. The pattern is reversed. Posterior maxillary bone is relatively preserved because the anterior teeth carry the load.

Correct answer: A. Surgical excision followed by prosthetic replacement

• A. Correct. Epulis fissuratum starts as reactive hyperplasia from a chronically overextended flange. Once dense fibrous tissue has matured it will not resolve on its own. Remove the irritant first, then excise the residual tissue with histological examination, and replace or reline the denture so the cause does not recur.
• B. There is no fungal component to a fibrous hyperplasia. Antifungals treat denture stomatitis, which is a different diagnosis.
• C. Further relief alone will not reverse mature fibrous hyperplasia, and continuing to observe simply delays definitive care.
• D. Steroids treat inflammatory and immune-mediated mucosal disease. This lesion is a fibrous overgrowth and will not respond.

Correct answer: D. The denture dislodges when the lips are pursed

• A. A sunken profile results from underextension of the vertical dimension or inadequate flange contour and thickness, but the immediate mechanical consequence of an underextended border is loss of seal.
• B. Sulcus ulceration is the signature of an overextended flange, which is the opposite error.
• C. The opposite occurs. A flange that stops short of the sulcus leaves a space that food readily enters.
• D. Correct. An underextended flange fails to reach the functional sulcus depth, so the peripheral seal is incomplete. Border seal is what generates retention through atmospheric pressure and surface tension, and without it the denture unseats during lip and cheek movements such as puckering.

Correct answer: B. To identify and measure undercuts and establish a path of insertion

• A. The occlusal plane is assessed clinically and on articulated casts.
• B. Correct. The surveyor holds the cast in a fixed relationship to a vertical analysing rod so that the height of contour can be marked, the path of insertion determined, and the depth of undercut measured with calibrated gauges of 0.01, 0.02 and 0.03 inches. Everything about clasp design flows from that survey.
• C. Vertical dimension is established clinically using rest position, phonetics and facial measurement, not on a surveyor.
• D. Centric relation is recorded clinically with record bases and rims and transferred to an articulator.

Correct answer: C. Support, by directing occlusal forces along the long axis of the tooth

• A. Stability resists horizontal and rotational forces and comes from rigid components contacting axial surfaces, such as the proximal plates, minor connectors and reciprocal arms.
• B. Reciprocation neutralises the lateral force generated by the retentive arm and is supplied by a rigid arm or plate on the opposing surface.
• C. Correct. A rest is the component that provides support. It transmits occlusal load down the long axis to the abutment and prevents the prosthesis settling into the tissues. The cingulum rest is preferable to an incisal rest because it sits closer to the horizontal axis of rotation and is more esthetic.
• D. Retention resists vertical displacement and is supplied by the retentive clasp terminal engaging an undercut, not by a rest.

Correct answer: D. Application of the Kennedy classification to removable partial dentures

• A. Tooth mould and shade selection follow facial form, complexion, age and patient preference.
• B. The posterior palatal seal is located from the vibrating line and the anatomy of the palate.
• C. Abutment selection for fixed bridges is guided by Ante's law and by crown-to-root ratio, root configuration and periodontal support.
• D. Correct. Applegate's eight rules resolve how the Kennedy classification is applied: classify after all extractions, let the most posterior edentulous area determine the class, count additional areas as modifications, ignore third molars if they are not to be replaced, and note that Class IV admits no modifications.

Correct answer: D. Fixed partial dentures

• A. Removable partial denture planning uses the Kennedy classification with Applegate's rules, together with support from both teeth and the residual ridge.
• B. Implant planning is governed by bone volume and quality, implant number and distribution, and the biomechanics of the prosthesis rather than by periodontal surface area.
• C. Complete dentures have no abutment teeth, so the concept does not apply.
• D. Correct. Ante's law states that the combined periodontal ligament surface area of the abutment teeth should equal or exceed that of the teeth being replaced. It is a guideline for planning fixed bridgework and for judging whether a span is too long for its abutments.