DENC 624 1st exam.pdf

Rayan DENC 624 Pros (complete denture) Q: List the clinical visit of CD? 1ST: diagnosis, prognosis and preliminary impression. 2nd: border molding...

Rayan DENC 624 Pros (complete denture) Q: List the clinical visit of CD? 1ST: diagnosis, prognosis and preliminary impression. 2nd: border molding and final impression. 3rd: occlusal plane and maxillomandibular relationship. 4th: try-in. 5th: final insertion. 6th: post operative. Q: what are the factors a/ecting the prognosis of CD? 1- Age (younger has better adaptive capacity). 2- Gender (men better than women). 3- Edentulous history record (edentulous for 20 years with 2 old dentures better than patient with 5 dentures). 4- Edentulous ridge (square form is more favorable, knife edge is least). 5- Residual ridge relationship (Class II most diQicult). 6- Palatal vault form (U shaped most favorable, V shaped least) 7- Torus (upper no need for correction, lower is needed). 8- Posterior palatal seal (wider and deeper is more favorable for retention) 9- Border tissue attachment (away from the crest is more favorable). 10- Soft tissue (normal of 2mm thickness is favorable, flappy or hard is unfavorable). 11- Saliva (thin serous saliva is favorable, thick is unfavorable). 12- Patient attitude personality (philosophical is ideal). Q: what are the steps before preliminary impression? - Position patient in comfortable upright position. - Lubricate lips with Vaseline. - Start with mandible first. Q: how to takes mandibular impression? - Use edentulous tray for small to average ridge, and dentulous trays for large. - Choose tray that extend slightly distal to the pear-shaped retromolar pad. - Extend the tray flanges with utility wax if needed. - Mix alginate according manufacture instructions. - Stand Infront and right of the patient. - Retract the right corner of the mouth then seat the tray rotating toward left corner then retract the check, lip and ask the patient to raise tongue up. - Hold the tray with index fingers at the premolar’s region with thumbs on the inferior border of mandible. - After removal from patient’s mouth, wash with tab water and dry with shaking. Q: how to takes maxillary impression? - Choose tray that extend distal to pterygo-maxillary notches and vibrating line. - If palatal vault is high, add extra alginate material at the center of the palate with finger or ass baseplate wax at the center of tray. - Stand to the right and slightly behind patient. - Retract the left corner of the mouth, seat the tray into the labial vestibule then bring back end of the tray up slowly (alginate is flowing toward the distal). Q: what is the lab work after you submit the primary impression? - Pouring impression. - Outline study cast. - Custom tray fabrication. Q: what should you check in custom tray? - About 2 mm short of the vestibule and frenulae - To the distal aspect of the pear-shaped pad. - I mm distal to the upper posterior border. Q: what is the objective of border molding? To obtain a peripheral seal for good retention and proper extensions for good support. Ideally, the impression borders should be similar in thickness and length to the final denture borders. Q: what needed in border molding? - Stick compound is the material of choice. - Patient should be seated in comfortable position. - The jaws should be parallel with the floor. Q: what are the Instructions for compound stick? 1- when heating compound on flame soften only the very end of stick 2- add only to small area not large area. 3- lubricate your gloves with Vaseline to easy manipulate. 4- Overbuild the area with compound allowing the patient musculature to push away the excess. 5- after heating the border area temper a few seconds in hot water bath to distribute the heat temperature of compound materials. Q: list in order the areas of border molding process of mandibular tray? 1- Posterior buccal area both side.. 2- Labial area. 3- Lingual Anterior area. 4- Dissto-Lingual area. Q: list in order the areas of border molding process of maxillary tray? 1- Buccal Posterior area both side. 2- Buccal area both side. 3- Labial area. 4- Posterior area. Q: What are the common errors in border molding process? - Overextension of border. - Underextensionof border. - Excessive pressure during molding. Q: What are the important points in the final impression process? - using light or medium bodied material and never with heavy - adjust patient position to make ridge parallel to the floor. - seat the tray firmly as instructed for alginate impression. - after material set, retract the lips and cheeks to break the seal and remove the tray carefully. - small defect like pressure areas, voids ok, but large defects require new impression. - wash and disinfect the impression. Q: what is the lab work after submitting the final impression? - Beading and boxing. - Pouring master casts. - Fabrication of record bases and occlusion rims. Q: what is the objective of occlusal plane? To determine the horizontal and vertical level of the teeth. Q: what is the objective of vertical dimension? To determine the amount of space between the rims with the jaws at rest and with the wax rims in occlusion. Q: what is the objective of face-bow transfer? To record the position of the jaws as related to the opening axis of the mandible and transfer this position so that the casts on the articulator will have the same relationship to the opening axis of the patient. Q: what is the objective of centric relation? To record the most posterior position of the mandible to the maxilla and transfer this position to the articulator. Q: what you will check in occlusion rims in both maxillary and mandibular? - Maxillary: around 22 mm length and width about 3-5 mm anteriorly and 6 to 10 mm posteriorly & wax rim should be centered on the ridge crest with anterior area slightly inclined labially - Mandibular: around 20 mm length and width about 3-5 mm anteriorly and 6 to 10 mm posteriorly. Q: what is the occlusal plane? an imaginary surface that is related anatomically to the cranium and theoretically touches the incisal edge of the incisors and tip of cusps of the posterior teeth. Q: how the occlusal plane established in relation to anatomical landmarks and the maxillary occlusion rim? 1- Parallel to Campers Line. 2- Parallel to the pupils of the eyes. 3- In length, the edge of maxillary rim is trimmed to about the length of the relaxed upper lip. Q: what are the key steps in establishing the occlusal plane using the maxillary occlusion rim? 1- Place the maxillary occlusion rim in the mouth and make certain it is comfortable and fits reasonably well. 2- Reduce or build out the labial portion so the lip is properly supported. 3- Establish correct length. parallel the rim with the pupils of the eyes and Camper's line. 4- Mark the maxillary rim to aid in the selection of the teeth. Q: what are the steps involved in marking the maxillary rim to assist in teeth selection? 1- Mark the midline. (Determine the midline using the philtrum of the lip, labial frenum, and the midline of the face). 2- Have the patient relax the lips. Mark the wax rim at the corner of the lips. These marks are the approximate width of the six anterior teeth. 3- Have the patient smile broadly and mark the high lip line with a wax spatula. Q: Vertical dimension at rest (VDR)? no teeth contact, muscles relaxed. Q: Vertical dimension at occlusion (VDO)? the vertical dimension were the teeth (occlusal rims) are in contact. Q: Freeway space? interocclusal space should be 2-4 mm (VDR-VDO). Q: how to measure the vertical dimension at rest? - Place a small dot on the tip of the nose and chin - lip lick ( Seat the patient in an upright position with noheadrest support. Lnstruct the patient to uncross the legs and let the arms rest limply on the arm rests and relax. - -Have patient lick lips and close slowly until the lips barely touch. Measure the distance between the dots two or three times. - ‘’M’’ “Hum” “Amma” pronounce. - Open wide for 1 mintute. Q: how to measure the vertical dimension of occlusion? Reduce the mandibular rim using hot plate to have 2-4 mm shorter than the rest position measurement while rims are in contact. Q: what is the importance of facebow transfer? - To transfer the position of maxillary arch in relation to the skull using third reference point. - Transfer the axis to the articulator and orienting the maxillary cast in the same relationship to the opening axis of the mouth. Q: what is the centric relation? is the most posterior relation of the mandible to the maxilla at a selected vertical dimension. must be recorded for edentulous patients as it is the only position that is repeatable. Q: how is the centric relation should record? centric relation is obtained using wax occlusion rims at the recorded vertical dimension of occlusion. 1- On the mandibular record block make a box by removing the wax form the posterior area to create space for registration materials 2- Inject the materials in the box and place the block in the mouth for CR relation registration. Q: what is the lab work after submitting the maxillomandibular relationship? 1- mounting master cast. 2- teeth arrangement in balanced occlusion. Q: how to evaluate the vertical dimension? - Record a new VDR. - Place the trial denture and ask the patient to count 60 to 70. - Observe sibilant sounds (S) and determine the space between maxillary and mandibular anterior teeth usually 1-2 mm is needed for a good ‘’S.’’ Sound. - Posterior contact during ‘’S’’ sound may indicate excessive OVD. - Observe patient at rest and swallowing, patient should be able to close comfortably with no eQorts, also lips should touch lightly, if over closed may indicate excessive OVD. - If possible, compare the OVD of the trial denture to the old denture as it should be the same or 1-2 mm higher. - If a change of 1-2 mm is needed its simply can be adjusted on articulator By closing the pin, if more reduction needed then a new CR needed. Q: how to evaluate the centric relation? - Check clinically - If adjustment needed remove the posterior teeth of lower arch and retake the CR with bite registration material. Q: what is the objective of posterior palatal seal? - Retention. - Prevention of food ingress. - Compensation for polymerization shrinkage. - Comfort. Q: where is the position of the posterior palatal seal? - lateral to the ptergyomandibular raphae and passing over the hamular. notch, running medially and distally to the junction of the hard and soft palate and about 1 mm. posterior to the vibrating line. Q: summarize the cast carving procedure? 1- the cast, if properly boxed and finished has adefinite posterior finishline for the denture and the record base must end on this line. 2- Mark thejunction of the movable and immovable tissue with a dot in the middle of the palate with an indelible stick. 3- place the record base on the master cast and score a line with a sharp instrument. 4- the indelible line should still be visible, palpate the tissue anterior to the line with a large end of the ball burnisher. 5- depth: about 1/2mm. deep lateral to and over the pterygo- mandibular raphae. As it broadens to the palatal portion, the depth should be no greater than 2 mm but not less than 1.5 mm. 6- width: The seal should completely fill the prehamular space 1-2mm in width. After it leaves the prehamular space it will broaden out to approximately 4 to 5 mm and narrow at the midline to about 3 to 4mm. Q: what are the parts of esthetic evaluation? - teeth color. - midline symmetry - length of the anterior teeth at rest, speaking and smiling - If anterior teeth touch when patient speaking, either upper teeth need to be moved labially or lower teeth need to be moved lingually. Q: what is the lab work after submitting the try-in denture? process, polish and correct any occlusal processing errors. Q: how you will examine the denture before insertion in patient mouth? - use your finger (no gloves) and feel the insides of the dentures for any sharp projections. - examine the borders for excessive thickness. Q: how would you insert the denture in patient mouth? - Insert the mandibular denture first then insert the maxillary denture after 15min (for tissue accommodation). - Ask the patient if there are any areas of discomfort. If reasonably satisfactory, place a cotton roll on each side at about the first molar area and instruct the patient to maintain a firm closure for 10 minutes. Q: what are the steps of pressure indication paste? - Wash and dry the intaglio surface of the dentures. - Brush a thin and even layer of paste over the entire surface. - Wet the denture before insertion in patient mouth. - Insert firmly and apply an even pressure in 1st molar area. - Remove and examine and reduce any pressure areas. Pay attention for the following areas: 1- Mandibular denture: (The mylohyoid ridge area & Lingual areas in the first bicuspid area & overlying sharp bony areas). 2- Maxillary denture: (Incisive papilla & Mid-palatine suture area) - Repeat the PIP until paste layer is even. Q: how to check the equilibration of occlusion? - use blue carbon paper for marking centric contacts and red for excursive movements. - use round acrylic bur on low-speed straight hand piece to obtain even contact in centric relation. - Interference in working side (extrusive lateral): use BULL role, remove from buccal for upper and lingual for lower teeth. - Interference in protrusive: grinding the distal surface of upper teeth and mesial surface of lower teeth. Q: what instruction would you give to the patient about denture wearing? - Always insert mandibular denture first. - Always remind patient that denture will be more comfortable with time also some problem may be expected. - Denture should be placed outside mouth for 8 hours every day to allow rest for the supporting tissues. Q: what instruction would you give to the patient about eating? - Instruct the patient to chew food simultaneously on both sides to greatly reduce tipping. - Patient should start with soft food initially and avoid sticky and hard food. Q: what instruction would you give to the patient about cleaning and maintenance? - dentures tend to accumulate food more than natural teeth, so patient is asked to clean denture every after meal and at night. - toothpaste and brush should be avoided as its very abrasive. - Commercially available denture cleaners and tablets might be used. - dentures need to be stored in water in an air-tight container. Q: what should be held in 24hours appointment? - Check for peripheral overextensions which will have a red line or even an ulcerated area if severe. - Check pressure areas with PIP. - Evaluate thickness of flanges and adjust needed conservatively. - Polish denture after adjustments. - Make second appointment after 48 hours and repeat the above. - A third appointment after 1 week is needed. Q: what are the reasons behind looseness or instability during post insertion? - InsuJicient posterior palatal seal. - Poor border seal. - Overextension. - Occlusion not balanced. Q: what are the reasons behind lower denture raise when mouth is opened? - poor border seal. - retruded tongue. - Anterior teeth too far labially. - InsuJicient clearance of lingual frenum. Q: what are the reasons behind sore spots? - A common problem usually related to poor occlusion or inadequate fit. - Entire ridge may indicate increased VD. - Red spots on crest, occlusion not balanced. - Patient habits: spicy food, over hard food. Q: what are the reasons behind infections? - Bacterial (Rare). - Viral: aphthous stomatitis. - Fungus: candidiasis. Q: what are the reasons behind allergies? - Denture base (rare). Q: what are the reasons behind gagging? - Psychogenic: starts in mind, very diJicult to treat. - Somatogenic: starts in body (usually dentures), treatable. Q: what are the reasons behind drooling at corners of mouth? - Closed VDO. - Excess salivation. - Poor neuromuscular control. Q: what are the reasons behind cheek, lip or tongue Biting? - Cheek (most common) inadequate overjet. - Lip biting due to poor teeth placement or poor neuromuscular control. Q: what are the reasons behind burning sensation? - It can be due to ill-fitting dentures, pressure on nerve foramina.  Pros (RPD) Q: list the Kennedy classes of RPD? - Class I: bilateral edentulous area located posterior to the natural teeth. - Class II: unilateral edentulous area located posterior to the natural teeth. - Class III: unilateral edentulous area with natural teeth remaining both anterior and posterior to it. - Class IV: a single but bilateral (crossing the midline), edentulous area located anterior to the remaining natural teeth. Q: Which of the Kennedy classes of RPD are tooth- borne? - Class III & Class IV. Q: Which of the Kennedy classes of RPD are tissue -tooth- borne? - Class I & Class II. Q: list the APPLEGATE’S rules? (8 rules) 1- Classification should follow rather than precede any extractions of teeth that might alter the original classification. 2- If a third molar is missing and is not to be replaced, it’s not considered in the classification. 3- If a third molar is present and is to be used as an abutment, it is considered in the classification. 4- If a second molar is missing and is not to be replaced, it is not considered in the classification. 5- The most posterior edentulous area always determines the classification. 6- Edentulous areas rather than those that determine the classification are referred to as modifications and are designated by their numbers. 7- The extent of the modifications is not considered, only the numbers of additional edentulous areas. 8- No modifications areas can be included in Class IV arches. Q: what are the components of RPD? 1- major connectors. 2- minor connectors. 3- Rests. 4- direct retainers. 5- stabilizing or reciprocal components (as parts of a clasp assembly). 6- indirect retainers (if the prosthesis has distal extension bases). 7- one or more bases, each supporting one to several replacement teeth. Q: what is the major connector? The unit of a partial denture that connects the parts of the prosthesis located on one side of the arch with those on the opposite side. Q: what are the functions of major connector? 1- Unification of the major parts of the prosthesis 2- Distribution of the applied force throughout teeth and tissue 3- Minimization of torque to individual teeth. This phenomenon is referred to as cross-arch stability Q: list the maxillary major connector types? 1- Palatal bar. 2- Palatal strap. 3- Anteroposterior palatal bar. 4- Anteroposterior palatal strap. 5- Horseshoe (U shaped). 6- Complete palatal plate. Q: give a brief about bars major connector? - 6-8mm. - Cross section is half round. - Types (middle, posterior, anteroposterior). Q: give brief about straps major connector? - 8-12mm. - 1.5 mm thickness. - Types (anterior, posterior, middle, anteroposterior). Q: give brief about palatal plates major connector? - Covers more than half of the palate. - Types (metallic, nonmetallic, combination). Q: explain the preferred designs for each class? - Class I: anteroposterior palatal strap if premolars present or palatal plate. - Class II: anteroposterior palatal strap. - Class III: single palatal strap. - Class IV: anterior U shaped of palatal plate. - Combination anteroposterior connector: Class II and IV. - Single palatal strap: Class III. - Palatal plate: Class I. Q: why should all maxillary major connectors cross the midline at a right angle rather than on a diagonal? It has been suggested that the tongue will accept symmetrically placed components far more readily than those placed without regard for symmetry. Q: what are the indications of using single broad palatal strap? 1- Class I partially edentulous arches with residual ridges that have undergone little vertical resorption and will lend excellent support. 2- V- or U-shaped palates. 3- Strong abutments (single or made so by splinting). 4- More teeth in arch than six remaining anterior teeth. 5- Direct retention not a problem. 6- No interfering tori. Q: what are the indications of using anteroposterior strap? 1- Class I and II arches in which excellent abutment and residual ridge support exists, and direct retention can be made adequate without the need for indirect retention. 2- Long edentulous spans in Class II, modification 1 arches. 3- Class IV arches in which anterior teeth must be replaced with a removable partial denture. 4- Inoperable palatal tori that do not extend posteriorly to the junction of the hard and soft palates. Q: what are the indications of using complete palatal plate? 1- In most situations in which only some or all anterior teeth remain. 2- Class II arch with a large posterior modification space and some missing anterior teeth. 3- Class I arch with one to four premolars and some or all anterior teeth remaining, when abutment support is poor and cannot otherwise be enhanced,residual ridges have undergone extreme vertical resorption; direct retention is diJicult to obtain. 4- In the absence of a pedunculated torus Q: what are the purposes of beading the maxillary cast? 1. To transfer the major connector design to the investment cast. 2. To provide a visible finishing line for the casting. 3. To ensure intimate tissue contact of the major connector with selected palatal tissue Q: what are the types of mandibular major connector? 1- Lingual bar. 2- Lingual plate. 3- Sublingual bar. 4- Labial bar. Q: what are the indications of lingual bar? Kennedy Class I, II III and IV arches where suJicient space exists between the elevated lingual sulcus and lingual gingival tissue.  Q: what are the contraindications of lingual bar? 1- Inoperable lingual tori 2- Highly attached lingual frenum 3- Interferences upon elevation of the floor of the mouth during functional movements. Q: what are the indications of using linguo-plate? 1- If the alveolar lingual sulcus so closely approximates the lingual gingival crevices 2- If the ridge in Class I undergo vertical resorption 3- For using periodontally weakened teeth in group function 4- When the future replacement of one or more incisor teeth will be facilitated by the addition of retention loops to an existing linguoplate. Q: what are the methods that commonly used to determine the height of the floor of the mouth? 1- Directly in patient’s mouth using periodontal probe. 2- Indirectly on the impression. 3- Indirectly on the cast. Q: why is it essential to block out all gingival crevices and deep embrasures? to avoid gingival irritation and any wedging effect between the teeth. Q: from which does the swing-lock consists of? consists of a labial or buccal bar that is connected to the major connector by a hinge at one end and a latch at the other end. Q: what is the indication of swing-lock concept? 1- Missing key abutments. 2- Unfavorable tooth contours. 3- Unfavorable soft tissue contours. 4- Teeth with questionable prognosis. Q: what are the purposes of minor connector? - Joining denture parts. - Transfers functional stress to the abutment teeth Transfers the effects of the retainers, rests, and stabilizing components throughout the prosthesis. Q: what are the requirements of minor connector? 1- bulk to be rigid 2- should not be located on a convex surface. 3- It should conform to the interdental embrasure, so that the gingival crossing is abrupt 4- It should be thickest toward the lingual surface, tapering toward the contact area  5- The deepest part of the interdental embrasure should have been blocked out to avoid interference during placement and removal, and to avoid any wedging effect on the contacted teeth. Q: what is the role of tissue stops? 1- designed for retention of acrylic- resin bases. 2- They provide stability to the framework 3- They are particularly useful in preventing distortion of the framework during acrylic- resin processing procedures. 4- Tissue stops can engage buccal and lingual slopes of the residual ridge for stability. Q: what are the purposes of the rests? 1- Provide vertical support for the partial denture. 2- Maintains components in their planned positions. 3- Maintains established occlusal relationships by preventing settling of the denture. 4- Prevents impingement of soft tissue. 5- Directs and distributes occlusal loads to abutment teeth. Q: what are the types of the rests? 1- Occlusal rest (molar- premolar). 2- Lingual rest (cingulum of canines). 3- Incisal rests (canines- incisors) 4- Embrasure hooks. Q: where should be located the deepest part of an occlusal rest seat? should be located near the centre of the mesial or distal fossa. From its depth, the floor of the rest seat should rise gently toward the marginal ridge. Q: When preparing an occlusal rest seat, why should the floor be inclined apically from the lowered marginal ridge, and what is the significance of ensuring an angle less than 90 degrees? Only in this way can the occlusal forces be directed along the long axis of the abutment tooth. An angle greater than 90 degrees fails to transmit occlusal forces along the supporting vertical axis of the abutment tooth. This also permits slippage of the prosthesis away from the abutment. Q: what is the purpose of the extended occlusal rest? minimize further tipping of the abutment and to ensure that the forces are directed down the long axis of the abutment. Q: Differentiate between suprabulge and infrabulge retainers? - Suprabulge: originate above the height of contour includes (Aker, reverse Aker, embrasure, wrought wire, combination clasp). - Infrabulge: originate below the height of contour includes (RPA, RPI) Q: what are the advantages of infrabulge retainers? 1- More efficient retention. 2- Less distortion of coronal contours. 3- Less tooth contact. 4- Cleaner. 5- more bothersome to vestibular tissues. 6- Less prone to caries. 7- Esthetically superior in most cases. 8- Greater adjustability. Q: what is the indication of bar clasp arm? 1- when a small degree of undercut (0.01 inch) exists in the cervical third of the abutment tooth, which may be approached from a gingival direction, 2- on abutment teeth for tooth-supported partial dentures or tooth- supported modification areas, 3- in distal extension base situations, 4- in situations in which esthetic considerations must be accommodated and a cast clasp is indicated Q: what is the contraindication of bar clasp arm? 1- a deep cervical undercut exists or when a severe tooth and/or tissue undercut exists. 2- When severe tooth and tissue undercuts exist, a bar clasp arm usually is an annoyance to the tongue and cheek and may traps food debris. 3- Shallow vestibule. 4- an excessive buccal or lingual tilt of the abutment tooth. Q: what is the indication of combination clasp? - Preferred to use on terminal abutments when torque and tipping are possible. - used when maximum flexibility is desirable, such as on an abutment tooth adjacent to a distal extension base or on a weak abutment. - used to reduce the effect of the Class I lever in distal extension situations includes a flexible component in the “resistance arm”. Q: what are the advantages of combination clasp? 1- Flexibility. 2- adjustability. 3- the appearance of the wrought- wire retentive arm. 4- esthetic advantage over cast clasps. 5- Wrought in structure, it may be used in smaller diameters than a cast clasp, with less danger of fracture. Because it is round, light is reflected in such a manner that the display of metal is less noticeable than with the broader surfaces of a cast clasp. Q: what does the combination clasp consists of? consists of a wrought-wire retentive clasp arm and a cast reciprocal clasp arm. Q: why does the circumferential clasp is the most logical clasp to use with all tooth- supported partial dentures? because of its retentive and stabilizing ability. Q: what are the disadvantages of circumferential clasp? 1- More tooth surface is covered. 2- Its occlusal approach may increase the width of the occlusal surface of the tooth. 3- In the mandibular arch, more metal may be displayed than with the bar clasp ar 4- its half-round form prevents adjustment to increase or decrease retention. Q: when should a ring clasp use? - It is used when a proximal undercut cannot be approached by other means. - Should be used on protected abutments. - The only justification for its use is when a distobuccal or distolingual undercut cannot be approached directly from the occlusal rest area and/or tissue undercuts prevent its approach from a gingival direction with a bar clasp arm. Q: when should the embrasure clasp use? - when the teeth are sound and retentive areas are available, or when multiple restorations are justified, clasping can be accomplished by means of an embrasure clasp. - always used with double occlusal rests. Q: where should the indirect retainer be placed? as far anterior from the fulcrum line. Q: what are the purposes of indirect retainer? 1- to effectively activating the direct retainer to prevent movement of a distal extension base away from the tissues. 2- tends to reduce anteroposterior tilting leverages on the principal abutments. 3- Contact of its minor connector with axial tooth surfaces aids in stabilization against horizontal movement of the denture. 4- Anterior teeth supporting indirect retainers are stabilized against lingual movement 5- - it may provide the first visual indications for the need to reline an extension base partial denture. Q: what are the forms of indirect retainer? 1- Auxiliary Occlusal Rest 2- Canine Rests 3- Canine Extensions from Occlusal Rests  4- Cingulum Bars (Continuous Bars) and Linguoplates 5- Modification Areas 6- Rugae Support. Q: What is the critical function of the denture base in a distal extension prosthesis? - supports the artificial teeth and consequently receives the functional forces from occlusion and transfers functional forces to supporting oral structures. - Secondary retention for the RPD is provided by the intimate relationship of denture bases and major connectors (maxillary) with the underlying tissues. Q: what are the factors influencing the retention of denture bases? 1- Adhesion. 2- Cohesion. 3- atmospheric pressure. 4- physiologic molding of the tissues around the polished surfaces of the denture 5- the effects of gravity on the mandibular denture. Q: What are the ideal characteristics of a denture base material? 1. Accuracy of adaptation to the tissues, with minimal volume change 2. Dense, nonirritating surface capable of receiving and maintaining a good finish 3. Thermal conductivity 4. Low specific gravity; lightweight in the mouth 5. Sufficient strength; resistance to fracture or distortion 6. Easily kept clean 7. Esthetic acceptability 8. Potential for future relining 9. Low initial cost Q: what is the denture base type according to the materials? - Resin type (acrylic denture base) - Metal type denture base. Q: what is the advantage of metal base? 1- Accuracy and Permanence of Form 2- Comparative Tissue Response 3- Thermal Conductivity 4- Weight and Bulk Q: what are the disadvantages of metal base? 1- Difficult to reline and rebase. 2- Expensive. 3- Cannot correct errors with metal denture base like posterior palatal seal. Q: Which type of denture Base is indicated for class I and II? Resin denture base. (in case of relining need). Q: what clinical sign indicates the need for relining? 1- rotational movement around the fulcrum line and the lifting of the indirect retainers, indicating a loss of ridge support. 2- when there is a loss of support, resulting in occlusal discrepancies. Q: what are the functions of guiding plane? 1- to provide for one path of placement and removal. 2- Help to stabilize, control and limit the movement of the RPD. 3- to eliminate gross food traps. Q: what are the uses of a surveyor? 1- surveying the diagnostic cast 2- Recontouring abutment teeth on the diagnostic cast 3- contouring wax patterns 4- measuring a specific depth of undercut 5- surveying ceramic veneer crowns 6- placing intracoronal retainers 7- placing internal rests 8- machining cast restorations 9- surveying and blocking out the master cast Q: name the parts of a dental surveyor? 1- Platform. 2- Table – hold casts. 3- Base – on which table swivels. 4- Vertical arm 5- Horizontal arm. 6- Surveying arm. 7- Mandrel for holding special tools. Q: what is blockout? Elimination of undesirable undercut areas on the cast to be used in the fabrication of a removable partial denture. Q: what is the purpose of shaped blockout? On buccal and lingual surfaces to locate plastic or wax patterns for clasp arms. Q: what is the purpose pf parallel blockout? Proximal tooth surfaced to be used as guiding planes, beneath all minor connectors. Q: what is the purpose of arbitrary blockout? All gingival margins, gross tissue undercuts situated below areas involved in the design of denture framework. Q: what is the purpose of relief? Beneath lingual bar connectors or the bar portion of the lingualplates when indicated. Areas in which major connectors will contact thin tissue, beneath framework extensions onto ridge areas for attachment of resin bases. Q: what are the advantages of using cast chromium alloy? 1- Resistance to tarnish. 2- Low material cost. 3- Low density. 4- Low flexibility. 5- High modulus of elasticity (stiffness) Q: what are the purposes of diagnostic cast? 1- Supplement the oral examination. 2- Topographic survey of the dental arch. 3- Presentation to the patient. 4- Impression trays fabrication. 5- Reference as the work progress. 6- Patient’s record. Q: what is the treatment option for short modification spaces? short spans (≤3 missing teeth), natural tooth– and implant-supported fixed prostheses as well as removable partial dentures can generally be considered. Q: what is the treatment option for long modification spaces? Longer span modification spaces (≥4 missing teeth) options for treatment include the removable partial denture and the implant- supported prosthesis. Q: what is the treatment option for Distal Extension Spaces? the removable partial denture is the only option (unless no treatment is elected) Q: which symptoms require conditioning treatment? - Inflammation and irritation of the mucosa covering denture-bearing areas. - Distortion of normal anatomic structures, such as incisive papillae, rugae, and retromolar pads. - A burning sensation in residual ridge areas, the tongue, and the cheeks and lips. Q: list the steps of RPD process? 1- Outlining the saddle area 2- Design for support 3- Design for connection 4- Design for bracing 5- Design for Stabilization 6- Design for reciprocation 7- Design for retention 8- Design for indirect retention Q: what is support? The resistance of tissue ward movement. Q: what are the means of support? A- Denture base. B- Rests. C- Some major connectors (plates). Q: what is the purpose of bracing? Counteract horizontal forces (resistance to lateral shifting movements & resistance to anteroposterior movements). Q: what are the bracing components? 1- Rigid clasp arm located above the survey line of teeth. 2- Major and minor connectors. 3- Proximal plates. 4- properly extended denture flanges and by covering the palatal slopes in maxillary dentures. 5- 5- Extension of maxillary dentures behind maxillary tuberosities and lower dentures to the recover the retromolar pads provide resistance to antero- posterior forces. Q: what is stabilization? The resistance of partial denture to tipping forces. Q: how would the stabilization achieve? 1- Adequate base coverage. 2- The use of three, and if possible four, widely separated areas of tooth support. 3- Rigid bracing clasp arms. 4- Balanced occlusal contact and reduction of cusp slope. 5- The use of additional rests on teeth other than the abutment tooth serves as indirect retainers. 6- Coverage of the slopping part of the palate anteriorly) acts as an indirect retainer. Q: what is the purpose of reciprocation? necessary to counteract forces acting on one side of the tooth by an equal and opposite force. Q: define the retention? Resistance to tissue away movements. Q: what is the means of retention? 1- Mechanical means (gingivally approaching clasp & occlusally approaching) 2- Physical forces. 3- Muscular control through the polished surfaces of the denture Q: how is the flexibility of a retentive clasp dependent upon its design? - Rounded clasp flex easily than half rounded. - the longer the clasp arm, the more flexible will be the clasp. Q: briefly write the steps of designing distal extended RPD case? 1- Denture base: combined metal acrylic for future relining, metal base is either ladder-like or meshwork for mechanical retention, maximum coverage, constructed in its displaced functional form. 2- Rests: mesially placed rest (rest seat away from edentulous space). 3- Direct retainer: flexible rather than rigid to allow slight movement, it can be any (RPI, I-bar, combination clasp, RPA, reverse Aker clasp, back action or reverse back action clasps). 4- Indirect retainer: two indirect retainers on each side to counteract displacing rotation forces (as far anterior to the fulcrum axis as possible). 5- Major connector: maxillary class I (anteroposterior palatal bars or straps and palatal plates). Mandibular class I (lingual bars with terminal rests or lingual plates with terminal rests). 6- Minor connector: rigid. 7- Guiding plane: they are flat axial parallel surfaces in an occluso-gingival direction of the proximal or lingual surfaces of teeth (height is 2-4mm and width determined by the proximal contour of the tooth). Pronounced guiding plane in distal extension base is not recommended. 8- Artificial teeth: small, narrow bucco-lingually, sharp cutting edge, lower teeth placed over the crest of ridge, centric occlusion coincide with centric relation, using swing-lock when indicating. Q: briefly write the steps of designing bounded RPD case? 1- Denture base: fit the static rather than functional form of the ridge. 2- Rests: placed on near zone, rest seat either prepared like box-shaped or saucer shaped. 3- Clasp: rigid clasps should be. 4- Major connector: maxillary (palatal bar or palatal strap). Mandibular (lingual bar).