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134 Cards in this Set
- Front
- Back
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What is the cameo surface of a denture?
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It is the viewable portion of a removable denture prosthesis; It is the part of the denture base that is usually polished and includes the buccal and lingual surfaces of the teeth.
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What is the flange of a denture?
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Rim used for strength, for guiding or attachment of another object.
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What is the intaglio surface of a denture?
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The portion of the denture or other restorative surface that has its contour determined by the impression.
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What are some important considerations for dentures that decrease as a person ages?u
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1. Denture support area<div>2. Neuromuscular control</div><div>3. Chewing force</div><div>4. Salivary flow due to medications</div><div>5. Healing capacity</div><div>6. Quality of denture bearing tissues</div>
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Explain why residual ridge resorption occurs?
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Physiologic tension from loading the PDL through natural teeth causes bone apposition. <div>Non-physiologic compression (like what may occur under dentures) results in resorption</div>
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In what direction does residual ridge resorption occur?
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Maxillary - Loss in the vertical and palatal direction<div>Mandibular - Loss is vertical and oriented along the cross-sectional shape of the mandible</div>
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Which ridge tends to lose more bone, maxillary or mandibular?
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Mandibular - resorption can be about 4x that of maxillary resorption
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What is the average loss of maxillary bone/year in the edentulous patient?
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0.1 mm/year<div>Loss in the first year is usually greater than this.</div>
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What is the concern for complete dentures in a type I diabetic?
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Epithelium is thinner and less keratinized.<div>This results in compromised support and impaired tolerance of complete dentures</div>
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What do the terms retention, stability, and support refer to in considering suitability for dentures?
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Retention = resistance to vertical displacement of denture<div>Stability = resistance to lateral displacement during function</div><div>Support = resistance to vertical forces of occlusion. Based on factors of the bearing surface that resists or absorbs occlusal loads during function.</div>
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What are some factors that impact retention, stability and support?
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1. Quality of oral mucosa<div>2. Alveolar ridge contour</div><div>3. Muscle attachments</div><div>4. Saliva</div><div>5. Neuromuscular control</div>
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How does quality of oral mucosa affect denture success?
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The more keratinized attached mucosa available, especially in the mandible, the better the support.
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Why is keratinized attached mucosa of more concern in the mandibular arch?
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In the mandibular arch, there is only a narrow zone of keratinized attached mucosa confined to the alveolar ridge.<div>Whereas in the maxillary arch, an abundance of keratinized attached mucosa covers the entire palate and alveolar ridges.</div>
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What problems with dentures arise with a loss of keratinized attached mucosa on the mandibular arch?
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Reduced support<div>Reduced tolerance to occlusal load</div>
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Describe the progression of resorption in the edentulous mandibular arch?
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Initially the bucco-lingual dimension of the alveolar ridge is narrowed (reduces support)<div>After that, the height of the ridge is reduced (reduces support, stability, and retention)</div>
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What are 3 important mandibular denture support areas?
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Retromolar pad<div>Buccal shelf</div><div>Alveoloar process (This is the most affected by bone resorption)</div>
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Which area of the mandibular arch is prone to perforation secondary to trauma from complete dntrues?
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The mucosa over the mylohyoid ridge. This area is poorly keratinized and calcification of the attachment of the mylohyoid muscle leads to a sharp bony projection.
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How might a frenum effect dunture retention?
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It may cause problems with retention by limiting denture extension or making a seal difficult to maintain
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How do you test floor of mouth posture?
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Place a mirror in the retromylohyoid space<div>Instruct the patient to move the tongue to the opposite side</div><div><br /></div><div>The less the mirror is displaced, the more favorable the floor of mouth posture and the longer the distal lingual flange will be.</div>
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How do the posterior palatine salivary glands contribute to denture adaptation?
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When making impressions of this area, the tissue is compressed, which allows some compensation for shrinkage of the acrylic resin during polymerization.
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What are the diagnostic criteria for bite classification of the edentulous patient?
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1. Mandibular bone height<div>2. Maxillomandibular relationship</div><div>3. Maxillary residual ridge morphology</div><div>4. Muscle attachements</div>
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What do bite classifications I-IV mean as far as denture compatablity?
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Class I - Ideal or minimally compromised<div>Class II - Moderately compromised</div><div>Class III - Substantially compromised</div><div>Class IV - Severely compromised</div>
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Describe the class I - III bites when considering dentures?
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Class I - Central incisors perpendicular to the ridge<div>Class II - Central incisors slightly palatally inclined</div><div>Class III - Central incisors slightly labially inclined</div>
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What are the maxillary tissue factors affecting retention?
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1. Shape of the palatal vault<div>2. Drape of the soft palate</div><div>3. Quality and quantity of saliva</div><div>4. Compressibility of posterior palatal seal area</div><div>5. Presence of well shaped tuberosities</div><div>6. Height of alveolar ridge</div>
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What are the tissue factors affecting denture retention in the mandible?
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Primary factors: <div>1. Tongue position</div><div>2. Floor of mouth posture</div><div>3. Neuromuscular control</div><div><br /></div><div>Secondary factors:</div><div>1. Peripheral seal</div><div>2. Adhesion</div><div>3. Cohesion</div>
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What are some maxillary tissue factors affecting stability?
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1. Alveolar ridge height<div>2. Presence of well formed maxillary, moveable denture bearing surface tissues </div><div>3. Presence of flabby (mobile) ridges</div>
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What are some mandibular tissue factors affecting denture stability?
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1. Alveolar ridge height<div>2. Floor of mouth contour</div><div>3. Tongue position</div><div>4. Neuromuscular control</div><div>5. Presence of flabby, moveable denture bearing surface tissues</div>
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What are some maxillary tissue factors affecting support of a denture?
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1. Amount of keratinized mucosa<div>2. Alveolar ridge contours</div><div>3. Palatal shelf area and contour</div>
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What are some mandibular tissue factors affecting support of a denture?
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Retromolar pad<div>Alveolar ridge contours ( the broader the better)</div><div>Amount of attached keratinized mucosa</div><div>Buccal shelf area (more access and greater surface area is better)</div>
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What must be included in the denture design to accomodate frenum?
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A notch in the denture flange. If the notch is inadequate, the denture border cuts the patient's frenum.
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What anatomical structure defines the border of the denture?
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The vestibule
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T or F: For a proper impression, the custom impression tray must be 1-2 mm short of the vestibular fold?
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True
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What happens if the vestibular extension of the denture is too narrow or too short? Too thick or too tall?
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Short and narrow - No retention<div>Thick or tall - Over-extension and pain</div>
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What complication occurs if the incisive papila is not properly reproduced on the intaglio surface of the denture?
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The denture will produce excessive pressure and pain in this area.
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What is the importance of the canine eminence in the making a denture?
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The canine eminence produces fullness in the anterior denture for lip support.<div>If the canine eminence is not sufficient, lip support will likely be inadequate.</div>
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How do the rugae contribute to the support of the denture?
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The area resists anterior displacement of the denture and is a secondary support area.
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What happens if the rugae are not properly reproduced in the finished denture?
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There will be pressure and irritation from the denture base
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What is the importance of the tuberosities in denture design?
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Tuberosities are an important primary denture support area that provide resistance to lateral movement of the denture.
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How is the denture effected if the patient's tuberosities are missing or poorly developed?
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Less resistance to rotation in the horizontal plane.
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How is the coronoid process represented in the denture border?
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As a concavity on the posterior lateral border.
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What are the foveae palatini useful for in the design of a denture?
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They are useful in determining the posterior extent of the denture and establishing the posterior palatal seal. They are positioned an average of 1.31 mm anterior to the vibrating line.
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How is the pterygomandibular raphe represented on a denture?
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As concavities on the border of the denture adjacent to each tuberosity.<div>They are produced when the patient opens wide and extends the chin during border molding.</div>
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What is the hamular notch?
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A narrow cleft that extends from the tuberosity to the pterygoid muscles.
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Improper molding of the hamular notch during the impression leads to what?
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soreness and loss of retention.
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What is the zygomatico alveolar crest?
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A bony ledge extending laterally from about the first molar region on both sides.
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Why should the zygomatico alveolar crest be considered when designing a denture?
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It is covered with thin, non-keratinized mucosa.<div>If the denture border is over-extended in this area, the denture will cut into the vestibular mucosa.</div>
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Why is the hard palate a primary support area for the maxillary denture?
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Because it resists resorption.
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T or F: A high palatal vault is not conducive to stability and support of a denture?
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True, due to the underlying inclined planes
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Why is relief in the denture required along the midline palatal suture?
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The overlying mucosa is tightly attached and thin and is prone to soreness.
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Why is relief in the area of the major palatine foramen usually not necessary?
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Although it is the opening for the greater palatine nerve, it is well protected by abundant overlying tissues.
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What is the primary load bearing area of the maxillary denture?
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Hard palate
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Describe the ideal maxillary ridge for a denture?
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Abundant keratinized attached tissue<div>Square arch</div><div>Palate U-shaped in cross section</div><div>Moderate palatal vault</div><div>Absence of undercuts</div><div>High frenum attachments</div><div>Well-defined hamular notches</div>
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What are the mandibular landmarks that must be observed and considered when designing a denture?
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Frenum<div>Buccal shelf</div><div>Mylohyoid ridge</div><div>Retromolar pad</div><div>Sublingual crescent</div><div>Labial vestibule</div><div>Buccal vestibule</div><div>Masseter groove</div><div>Retromylohyoid</div><div>Lingual sulcus</div>
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Why is the buccal shelf a prime support area for the mandibular denture?
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It is parallel to the occlusal plane and the bone is very dense. It is also resistant to resorption.
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What is the primary load bearing area of the mandibular denture?
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The buccal shelf
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What is used as an anatomic guide for the lateral terminationof the buccal flange?
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The external oblique line.
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Where is the external oblique line of the mandible located?
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It runs distally and superiorly from the mental foramen to become continuous with the anterior region of the ramus.
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What are the borders of the buccal shelf?
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It is bordered externally by the external oblique line<div>It is bordered internally by the slope of the residual ridge.</div>
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T or F: The size and position of the buccal shelf vary relative to the degree of alveolar ridge resorption?
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True
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How do you develop proper border contours of the labial and buccal vestibule of the mandibular denture?
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Have the patient elevate the lower lip and purse lips
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How does the mentalis muscle effect the design of a denture?
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Movement of the mentalis muscle influences the length and thickness of the border of the anterior flange of the lower denture.
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How can you tell if the custom tray is too long in the area of the mentalis muscle?
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The tray will raise on its own when tried in.
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What is the secondary support area of the mandibular denture?
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The alveolar ridge.
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Describe the ideal mandibular alveolar ridge for a denture?
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Covered in keratinized tissue<div>Free from undercuts</div><div>Full and wide</div>
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Why is the retromolar pad considered a primary load bearing area?
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The underlying bone in this region does not resorb as quickly as elsewhere.
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What is contained in the retromolar pad area?
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Glandular tissue<div>Loose areolar connective tissue</div><div>Lower margin of the pterygomandibular raphe</div><div>Fibers of the buccinator</div><div>Fibers of the superior constrictor</div><div>Fibers of the temporal tendon</div>
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How do you border mold the lingual frenum area?
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Have the patient elevate and extend the tongue.
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When must you relieve the denture base in the area of the mental foramen?
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When there is severe residual ridge resorption. This places the mental foramen more superior and more prone to compression and irritation.
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What are the borders of the retromylohyoid space?
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Medially - Anterior tonsilar pillar<div>Posteriorly - retromylohyoid curtain</div><div>Laterally - Mandible and pterygomandibular raphe</div><div>Anteriorly - Lingual tuberosity of mandible</div><div>Inferiorly - mylohyoid muscle</div>
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Why is it important to extend the lingual denture flange into the retromylohyoid space?
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This area provides stability and retention.
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The geniotubercle (mental spines) provide attachment for what muscles?
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Genioglossus<div>Geniohyoid</div>
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What determines the lingual flange extension of the denture?
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The mylohyoid ridge of the mandible
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What is the function of the suprahyoid muscles?
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Elevation of the hyoid bone and larynx<div>Depression of the mandible</div>
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What are the suprahyoid muscles?
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Digastric<div>Stylohyoid</div><div>Mylohyoid</div><div>Geniohyoid</div>
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Why should the mylohyoid ridge be palpated in preparation to design a denture?
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Determine its contour, sharpness, and degree of undercut.
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What are the characteristics of an ideal mandibular ridge for dentures?
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Well defined retromolar pad<div>Blunt mylohyoid ridge</div><div>Deep retromylohyoid space</div><div>Low frenum attachments</div><div>Absence of undercuts</div><div>Abundant attached keratinized mucosa</div><div>Adequate alveolar height</div>
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How does denture design relate to the muscles of facial expression?
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They generally do not insert in bone and need support from the teeth and denture flanges for proper support and function.
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What is the modiolus?
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A concentration of several muscle groups situated at the corner of the mouth.
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How does the modiolus relate to denture design?
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It is a very forceful area which can influence the labial flange thickness of the maxillary denture.
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T or F: As people age, tension is lost in the buccinator, which predisposes an individual to cheek biting?
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True
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What does the mentalis do?
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Elevates the skin of the chin and turns the lower lip outward.
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How does the mentalis relate to denture design?
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It dictates the length and thickness of the labial flange extension
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What is the masseteric groove?
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A groove visualized in the final denture impression that is produced by the action of the masseter. If it is not captured in the impression, the denture may impinge on the action of the masseter and cause pain.
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How can the masseteric groove be produced in the final impression?
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Have the patient open wide and move the chin forward and side to side.
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What will result if the denture flange is overextended into the sublingual area?
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It will destabalize the denture and can lead to trauma of the mucosa on the floor of the mouth.
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What forms the sublingual folds?
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Superior surface of the sublingual glands and the ducts of the submandibular glands.
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What is the difference in the intrinsic and extrinsic muscles of the tongue?
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Intrinsic - Originate and insert within the tongue. Produce changes in the shape of the tongue<div>Extrinsic - Originate in structures outside the tongue. Move the tongue and alter its shape</div>
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What are the extrinsic muscles of the tongue?
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Genioglossus<div>Styloglossus</div><div>Hyoglossus</div><div>Palatoglossus</div>
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What percent of tongues are abnormal in either size, position, or shape?
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35%
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T or F: A retruded tongue position is very unfavorable for denture retention and stability?
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True, because it elevates the floor of the mouth and eliminates room for the lingual flanges
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How does a tongue with normal configuration effect stability and retention of a denture?
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It aids stability and retention by pressing evenly against the lingual flanges.
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Describe the mucocompressive technique for fabricating a custom tray and taking the impression?
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No relief is used on the cast.<div>When the impression is taken, the tray causes compression over the entire area equally and captures the impression in the compressed state.</div>
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What is the disadvantage to the mucocompressive technique?
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A denture made from this technique may result in trauma to the areas with thinner tissue covering the hard bony areas.<div><br /></div><div>It is also believed that when occlusal forces are released the tissue will rebound, dislodging the denture.</div>
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Describe the mucostatic technique for fabricating a custom tray and taking a denture impression?
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Relief wax covers the entire bearing surface of the cast, resulting in a tray with space between the tray and tissue surface.<div>Holes are also made in the tray to allow impression material to escape.</div><div>This technique allows the impression to capture the tissue in a minimally stressed state.</div>
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What is the basis of the mucostatic impression technique?
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Pascal's law: Pressure exerted anywhere in a confined incompressible fluid is transmitted equally in all directions throughout the fluid such that the pressure ratio remains the same.
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What is the flaw in the mucostatic technique?
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The tissue thought to represent a confined incompressible fluid is not actually a confined fluid. Because blood and interstitial fluid can escape the denture bearing area, the tissue can compress in areas unable to withstand the force.
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What is the selective pressure technique for taking a denture impression?
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Uses no relief wax over primary and secondary support areas, but relief is provided over the areas which are unable to withstand pressure.<div>The tray that results allows for pressure to be applied to areas that can withstand the pressure.</div>
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What is the most widely used denture impression technique?
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Selective pressure.
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Why do we learn the selective pressure technique?
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Because it is accepted by the majority of dental schools.<div>However, each technique has been used in clinical practice successfully.</div>
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What does relief wax do?
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It provides space between the tray and the tissue and allows an impression that causes minimal stress to areas that cannot withstand pressure.
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What are the relief areas on the maxillary cast?
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Midline suture<div>Rugae</div><div>Incisive papilla</div><div>Any other area where thin tissue covers hard prominent bone.</div>
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What are the relief areas on a mandibular cast?
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Crest of anterior ridge<div>Crest of posterior ridge if it is sharp (If it is broad it may not need relief)</div><div>Mylohyoid ridge if it is prominent</div><div>Retromolar pad</div><div>Any other area where thin tissue covers hard prominent bone.</div>
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What are the objectives of the final impression?
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1. Form a replica of the maxilla or mandible upon which the final prosthesis will be constructed<div>2. Must faithfully reproduce all relevant details of the maxilla/mandible</div><div>3. Must not extend beyoind physiologic borders as defined by anatomical structures and landmarks</div>
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What material is used for making the final impression?
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Maxilla - Light body PVS<div>Mandible - Medium body PVS</div>
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What is the sequence for making a final impression?
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1. Establish the health of the denture bearing areas<div>2. Try in custom impression tray and adjust the length of the flanges 2-3 mm short of the vestibule depth.</div><div>3. Establish 3D contours of the denture borders by border molding the custom tray with Adaptol.</div><div>4. Take impression with the appropriate PVS material</div>
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What should you instruct the patient to do in preparation for their final impression appointment?
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Leave out their dentures for 24 hours prior to the final impression appointment.
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Why should the tray be 2 mm away from the vestibular fold?
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To allow enough room for border molding compound and impression material.
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What are some important principles for successful border molding?
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1. Start with an accurate preliminary impression<div>2. Requires a well-crafted custom tray</div><div>3. Requires attention to and representation of the anatomic landmarks</div><div>4. Use a "plastic, rubber" material (dead-soft and deforms readily)</div>
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Why is border molding such a critical step?
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The borders of the impression define the physiologic extent of the denture
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What happens if the borders of the final impression are over-extended? Under?
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Overextended - The denture border will traumatize the soft tissues. Denture may also dislodge<div><br /></div><div>Underextended - Stability is reduced.</div>
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What are some non-elastomeric impression materials that can be used for final impressions?
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Zinc oxide-eugenol paste<div>Plaster of paris</div><div>Modeling plastic (impression compound)</div>
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What are some elastomeric impression materials?
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Condensation silicone<div>Polyvinyl siloxane</div><div>Poly sulfide</div><div>Poly ether</div>
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What are some characteristics of zinc oxide and eugenol as an impression material?
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Records soft tissue at rest<div>Fast set</div><div>Rigid (undercuts difficult)</div><div>Poor taste</div>
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What are some characteristics of reversible hydrocolloids?
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Rely on heat to soften the material and cooling to gel it<div>Can be re-softened by reheating</div><div>Quite accurate and reliable</div><div>Difficult technically</div>
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What are some characteristics of irreversible hydrocolloid?
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<div>AKA alginate</div>Hydrophilic but viscous<div>Used with a stock tray to produce cast for custom tray fabrication</div>
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What are some characteristics of condensation silicone?
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During the polymerization process, EtOH is released causing approximately 1% shrinkage of the impression.<div>Rarely seen because it is not especially accurate</div><div>May be useful in impressions for rpd relines</div><div>Cannot be mailed to a remote lab.</div>
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What are some characteristics of addition silicone (PVS)?
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Most commonly used material today<div>Most accurate, less shrinkage</div><div>Can be mailed to a remote lab</div><div>Can be expensive</div><div>Hydrophilic qualities vary with manufacturer</div><div>Neutral odor and taste </div><div>Studies have demonstrated a negative correlation between latex gloves and polymerization of polyvinyl siloxane</div>
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Why is the resulting impression from PVS materials more accurate than condensation materials?
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There are no small molecule by-products in the reaction.
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H2 gas forms during autopolymerization of PVS material, what considerations must be taken because of this fact?
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H2 gas must be eliminated prior to pouring the impression or the cast will be covered in bubbles. This can be accomplished by waiting 30 min to pour the impression.
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What are some advantages to PVS?
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Ease of mixing and dispensing<div>No odor</div><div>Ease of clean-up</div><div>Stable - does not have to be poured immediately</div>
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What are some disadvantages of PVS?
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Expensive<div>Not as hydrophylic</div><div>Excessive flow</div>
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How much does a PVS impression cost?
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It costs about $20 per impression
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What are some characteristics of polysulfide impression materials?
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First dental elastomers<div>Rubber base</div><div>Poor taste</div><div>Poor dimensional stability</div><div>Poor elastic recovery</div><div>Handling characteristics very dependent upon the environment (temp and humidity)</div>
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What are some characteristics of polyeter impression materials?
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Accurate and stable<div>Expensive</div><div>Objectionable odor and taste</div><div>More difficult to handle</div><div>Can be mailed to a remote lab</div><div>Set very firm and can be difficult to remove from the mouth.</div>
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What is a precaution that needs to be taken when making a cast from a polyether impression?
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Be careful not to break the cast when separating the stone from the impression because the polyether sets so stiff.
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Which type of impression material is the easiest to use? Which is the most technique sensitive?
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Easiest - Addition Silicone<div>Technique sensitive - Agar</div>
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Which impression materials are unpleasant to the patient?
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Agar - thermal shock<div>Polysulfide - stains</div><div>Polyether</div>
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Which is the most difficult material to remove from the mouth?
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Polyether
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Which impression material is the most responsive to disinfection? Least?
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Most - Addition silicone<div>Least - Agar, Alginate</div>
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What impression material has the longest set time?
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Polysulfide
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Which impression materials have the greatest wettability and castability?
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Agar and Alginate
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What is the most expensive impression material? Least?
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Most - Addition silicone, polyether<div>Least - Alginate</div>
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Once you have seated the tray for the final impression, what do you do next?
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Manipulate the tissue as during border molding:<div><br /></div><div>Massage face</div><div>Pucker lips</div><div>Smile</div><div>Move jaw side to side</div>
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What are some characteristics os a good maxillary final impression?
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Smooth well defined borders<div>Maximum extension</div><div>Even pressure distribution ( No show through)</div><div>Intimate tissue contact</div>
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