- The functions of a complete denture are to restore mastication, phonetics, and esthetics.
- The primary stress-bearing area in the maxilla is the horizontal slopes of the maxilla.
- The primary stress-bearing area in the mandible is the buccal shelf.
- The mean denture-bearing area in the edentulous maxilla is 22.96 sq cm and the mandible is 12.25 sq cm.
- Residual ridge resorption is the continuous loss of bone after tooth extraction and even after the placement of a complete denture.
- The rugae is the secondary stress-bearing area in the maxilla.
- Slopes of the residual ridges are the secondary stress-bearing area in the mandible.
- Mid-palatine raphe and incisive papilla are the relief areas in the maxilla.
- The greater palatine foramen is positioned in such a way that it does not need relief.
- Mid-palatine raphe needs relief as there is very minimal thickness of mucosa coverage.
- Incisive papilla covers the incisive foramen.
- Nasopalatine nerves and vessels are transmitted through the incisive foramen.
- The crest of the residual ridge is the relief area in the mandible.
- A torus needs to be relieved if present in either of the denture-bearing areas.
- The retromolar pad area resists resorption as it has an insertion of the temporalis, buccinator, and fibers of the superior pharyngeal constrictor.
- The sublingual crescent area is also called the mylohyoid region.
- The posterior palatal seal (PPS) is the seal achieved in the posterior aspect of the maxillary denture, which prevents air and fluid entry.
- The posterior palatal seal area lies between the anterior and posterior vibrating lines.
- Over-extended PPS can lead to gagging and loss of denture retention.
- The masseteric notch is seen in the buccal flange of the mandibular denture.
- Maxillary torus is seen commonly in the mid palatal area.
- Objectives of impression-making are the preservation of the residual ridge, retention, esthetics, stability, and support. [PRESS]
- Different theories of impression-making are ecstatic, much compressive, and selective pressure.
- The mucostatic impression technique is proposed by Harry L Page.
- The mucostatic or minimal pressure technique was first proposed by Richardson and later popularized by Henry Page in 1946.
- Mucocompressive or definite pressure theory was put forward by the Greene brothers.
- The selective pressure technique was put forward by Boucher.
- Contents of the retromolar pad are loose connective tissue, glandular tissue, fibers of the temporalis tendon, buccinator, superior constrictor, and pterygomandibular raphe.
- The temperature of water used for manipulating the impression compound is 60 to 70° C.
- A much compressive impression can cause ischemia of the tissues leading to excessive basal bone resorption.
- The much compressive technique exerts excessive pressure continuously over the denture-bearing area leading to increased bone resorption and loose denture.
- Materials used for the mucositis technique are impression plaster and thin mix of alginate.
- Lack of peripheral seal in the mucositis technique can lead to poor retention.
- The mucostatic impression technique utilizes adhesion, cohesion, and interfacial surface tension for retention.
- A mucositis impression is indicated when there is a loss of resiliency of the mucosa, for Example, Submucous fibrosis.
- Ortho-ethoxy benzoic acid is used to replace eugenol in eugenol-free impression pastes.
- The spacer thickness needed for zinc oxide eugenol impression paste is 0.5 mm.
- Elastomeric impression materials require a spacer thickness of 0.5 to 1.5 mm depending on the viscosity of the impression material.
- A full spacer is used for minimal pressure technique in diabetic patients and submucous fibrosis patients.
- An I-shaped spacer is indicated in the shallow vault.
- A dumbbell-shaped spacer is indicated in the deep palatal vault.
- In anterior flabby tissue ridges a T spacer is the choice.
- Tissue stops in the impression trays are used to obtain a uniform thickness of the impression material and for correct positioning (reorienting) of the trays after the removal of spacers.
- During the impression procedure, the patient should be seated upright with the occiput resting firmly on the headrest.
- Under extended stock trays can be corrected by using impression compound or modeling wax.
- The temperature of the water bath for softening impression compound is 55° to 70°C.
- Border molding is done by an incremental method using a green stick or one-step method with rubber base material.
- Tempering is the procedure of immersing in warm water before insertion of impression compound or low-fusing green stick compound.
- Try adhesives to be applied over the acrylic tray before doing border molding and secondary impression using rubber base impression materials.
- 50. Alpha butyl styrene is used as tray adhesive for rubber base impression material.
- Tray exposures seen on the fitting surface of the impression after making the secondary impression shows the impression is made with too much pressure and these areas can become pressure spots in the denture.
- The shapes of the occlusal rims can be square, tapering or ovoid.
- The maxillary denture is primarily retained by the negative atmospheric pressure complemented by the intact peripheral seal.
- The posterior palatal seal compensates for the volumetric shrinkage of the denture during curing.
- Boundaries of PPS are the anterior vibrating line, the Posterior vibrating line, and the pterygomaxillary notch.
- The anterior vibrating line is cupids bow-shaped due to the presence of the posterior nasal spine.
- The anterior vibrating line is always located on the soft palate.
- The posterior vibrating line marks the most distal extension of the denture base.
- Jaw relation recording is considered the most important step in complete denture fabrication.
- Orientation jaw relation orients the mandible to the cranium.
- A face bow records the axis of rotation of the mandible and transfers this axis to the articulator.
- The axis around which the mandible rotates is known as the transverse axis or hinge axis.
- The face bows can support the maxillary cast during mounting in the articulator.
- Face bows are of two types arbitrary and kinematic.
- Arbitrary face bows can be either fascia type or earpiece type.
- During face bow transfer three reference points are considered in the skull. Two points are located posterior to the maxilla and one is located anteriorly.
- The plane of orientation is the spatial plane obtained by joining the anterior and posterior reference points.
- The posterior reference points represent the terminal hinge axis position.
- An arbitrary face bow is used for the fabrication of a complete denture.
- An arbitrary face bow is attached to the maxillary occlusal rim whereas the kinematic face bow is attached to the mandibular occlusal rim or clutches.
- When the external auditory meatus is used as the posterior reference point, it is considered to be positioned within 5 mm of the true center of the opening axis of the jaws.
- The kinematic face bow locates the true terminal hinge axis.
- Kinematic face bows are generally indicated for FPDs and full-mouth rehabilitation.
- Fascia-type face bows have condylar rods instead of earpieces.
- The intercondylar scale is a part of the whip-mix quick-mount face bow.
- Face bow transfer avoids errors in the occlusion of the finished prosthesis.
- Freeway space = vertical dimension at rest – vertical dimension at occlusion.
- A freeway space of 2 to 4 mm at the premolar region is recommended in the complete denture.
- Silverman’s closest speaking method is a technique to verify the freeway space.
- Philp Paff was the first person to describe the technique of recording jaw relation.
- Centric relation is the most posterior relation of the maxilla to the mandible at the established VD.
- Centric relation is a reliable, repeatable, and recordable position (3R).
- In CD patients the proprioceptive impulses from the TMJ guide the mandible to centric relation.
- The centric relation and centric occlusion in CD patients should coincide.
- Any relationship of the mandible to the maxilla other than the centric relation is eccentric jaw relation.
- Eccentric jaw relation records are used to program adjustable articulators, i.e. to adjust
the lateral and horizontal condylar inclinations in the articulator. - As the mandible protrudes the condyles move downward and forward to create a triangular space between the posterior teeth called the Christensen phenomenon.
- As the mandible moves to one side, the condyle on the opposite side moves downward, forward and inward. This movement of the balancing side condyle is known as the Bennett movement.
- In Hanau articulators lateral condylar angles are set by the formula L=H/8+12.
- In Hanaus’s formula H is the horizontal condylar angle.
- The posterior reference points are marked 13 mm anterior to the tragus on the traguscanthus line.
- Earpiece face bows are positioned directly in the external auditory meatus.
- The graphic methods of recording centric relation are arrow point tracing (gothic arch tracing) and pantographic tracing.
- In intraoral tracing, the central bearing plate is attached to the maxillary rim and the central bearing point or stylus is attached to mandibular rim.
- In intraoral tracing the arrow points posteriorly.
- It is difficult to see the intraoral tracing hence guiding the patient is difficult.
- In extraoral tracing the central bearing plate is attached to the lower occlusal rim and the
central bearing pin is attached to the upper occlusal rim. - Pantographic tracing records the mandibular movements in three planes.
- Pantographic tracing is the most accurate method of recording centric jaw relation.
- A fully adjustable articulator is needed to accept pantographic tracing.
- Typal form theory for the shape of the teeth is proposed by Leon Williams.
- Anatomic teeth are having a cuspal inclination of 33° or 30°.
- Pilkington-Turner teeth are having a cuspal inclination of 30°.
- Semianatomic teeth have a cuspal inclination of 10 or 20°.
- Balanced occlusion is obtained easily with semi-anatomic teeth.
- Non-anatomic teeth are 0° teeth also called monoplane teeth.
- Non-anatomic teeth are indicated in patients with flat and severely resorbed ridges, poor neuromuscular control, and bruxism.
- Anthropometric measurements are used to determine the mesiodistal width of the anterior teeth.
- The buccal corridor is the space present between the buccal teeth and buccal mucosa.
- The natural teeth occupy a zone of equilibrium between the buccal musculature and lingual musculature. This zone is known as the neutral zone.
- Artificial teeth are arranged in the neutral zone for better stability.
- A squint test is used to select the shade of the tooth. It is used to compare the color of the tooth with the color of the face.
- Frush and Fisher proposed the ketogenic concept for the arrangement of anterior teeth
based on the patient’s age, sex, and personality. - Interpenetrating polymer network (IPN) teeth are preferred over conventional acrylic teeth.
- Different types of occlusal concepts in complete dentures are:
- Balanced occlusion
- Non-balanced occlusion
- Spherical concept of occlusion
- Organic concept of occlusion
- Neutrocentric concept of occlusion
- Lingualized occlusion.
- Who introduced the cusp to fossa occlusion –S.H. Payne (1941).
- Sheppard stated that “Enter bolus, Exit balance” According to this statement, the balancing contact is absent when food enters the oral cavity
- Alfred Gysi 1927 introduced the concept of lingualized occlusion.
- Hardy’s concept proposed a flat occlusal plane with non-anatomic teeth.
- Types of balanced occlusion are unilateral bilateral and protrusive.
- Balanced occlusion is absent in natural dentition.
- The factors which affect balanced occlusion are known as Hanau’s Quint.
- Hanau’s quint
- Condylar guidance
- Incisal guidance
- Compensating curves
- Relative cusp height
- Plane of the orientation of the occlusal plane.
- The condylar path is the only factor that is not under the control of the dentist.
- Teeth with a high cuspal height are required for patients with steep condylar guidance.
- The compensating curves compensate Christensens’ phenomenon during excursive movements of the mandible.
- Anatomic curves which are present in the natural dentition are:
- Curve of Spee
- Curve of Monson
- Curve of Wilson
- Anteroposterior curvature is the counterpart of the curve of Spee.
- Lateral curvature is the counterpart of Monson’s curve.
- Arcon articulators have the condylar elements as part of the lower member.
- The anterior teeth should be arranged with the incisal edge visible by 1 to 2 mm.
- The central incisor should be positioned 8 to 10 mm anterior to the midpoint of the incisive papilla.
- Bi-labial sounds are b, p, and m.
- Labiodental sounds are f and v.
- Lingo-alveolar sounds are t, d, n, s and z.
- Lingo-dental sound is th.
- Valar sounds are k, g, and kg.
- The closer the teeth are arranged to the ridge the better the stability.
- The wax surface around the teeth is called the art portion.
- The mandibular denture has to be inserted before the maxillary denture.
- The occlusal harmony of the denture is checked using interocclusal check records and articulating paper.
- The first appointment should be made 24 hours after insertion to correct occlusal disharmony and immediate tissue reaction.
- Relining is adding new material to the fitting surface of the existing denture.
- Relining techniques are:
- Static
- Functional
- Chairside
- The functional reline technique utilizes tissue conditioners as impression material.
- An immediate denture is one that is fabricated before all the remaining teeth have been extracted and is inserted immediately after the removal of the teeth.
- An interim immediate denture is to be used for a short period of time for reasons of esthetics, mastication, etc. until a more definitive prosthetic therapy can be provided.
- Porosity is a processing error in acrylic dentures which may compromise the physical, aesthetic, and hygienic properties of the processed denture.
- The longevity of tissue conditioners is limited due to leaching out of plasticizer and alcohol within 4-8 weeks of time.
- Tissue conditioners are composed of Polymethyl methacrylate and a mixture of aromatic esters and ethyl alcohol.
- Selective grinding is the procedure used for the final correction of any occlusal disharmony of the complete denture.
- If the incisal guide pin rises from the incisal table of the articulator during lateral
movements, the buccal cusps of the upper and the lingual cusps of the lower on the working side are to be reduced (BULL grinding). - Combination syndrome is the most common problem seen in patients wearing maxillary single complete dentures opposing distal extension mandibular partial dentures.
- Over-extended borders of the complete denture can lead to epulis fissuratum.
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