RCD Exam 1 Actual Questions With Correct Detailed Answers Graded A+.

What percentage of procedures in General Dentistry involve Removable Prosthodontics? - correct answer 30% More than ___ million Americans don't have any teeth and ___ million people are missing at least one tooth. - correct answer 35 million 178 million 3 factors leading to a patient becoming edentulous - correct answer Level of caries and periodontal disease Attitude, behavior, and dental attendance Low socioeconomic status ___ provides a resilient suspensory apparatus resistant to functional forces - correct answer Periodontium This includes both the hard connective tissues (cementum and bone) as well as the soft connective tissues (PDL and lamina propria of gingiva) What are the two principal functions of the periodontium? - correct answer Support and positional adjustment of the tooth When are teeth in occlusion? - correct answer During deglutition (swallowing) Occasionally while masticating During clenching and grinding (parafunction) Are forces on prosthetic occlusion likely to be controlled and attenuated more or less effectively as they appear to be by natural dentition? - correct answer Forces are less effectively controlled and attenuated Thus, the time-dependent responses of tissues supporting complete dentures are likely to be different from those around natural teeth. How do the areas of periodontal support compare in the functional periodontium vs an edentulous arch? - correct answer Functional: approx. 45 cm^2 in each arch Edentulous: approx 23 cm^2 of maxillary mucosa for support and approx 12 cm^2 of mandibular mucosa for support What is the significance of the edentulous arch having a smaller mucosal surface area? - correct answer Forces are more destructive on a smaller area What properties does the periodontium have? - correct answer Viscoelastic Sophisticated sensory mechanism Potential for bone remodeling What is meant by the adaptability of the mucosa? - correct answer Natural arch has good adaptability to wear Edentulous arch has little tolerance to denture wearing; results in destruction or inflammation What causes bone loss when teeth are missing? - correct answer Presence of tooth keeps bone in place (osteoblastogenesis) When the tooth is gone, there is no need to maintain the vertical height of the bone, so osteoclastogenesis commences What factors worsen adaptability? - correct answer Systemic diseases such as anemia, hypertension, or diabetes, nutritional deficiencies Any disturbance affects mucosal tolerance and initiates inflammation What is the masticatory force of natural teeth? - correct answer 200 N What is the masticatory force of a complete denture? - correct answer 60-80 N maximum This is 5-6 times less than that of natural teeth What causes the difference in masticatory forces between natural teeth and complete denture? - correct answer There is sensory input in natural teeth However, in implant-supported CD, the masticatory force is greater than for natural teeth because there is no nerve providing feedback to muscles to stop. Thus, CD<natural teeth<implant What does the residual ridge consist of? - correct answer 1. The denture-bearing mucosa 2. The submucosa and periosteum 3. The underlying bone What happens to bone after extractions? - correct answer The alveoli are filled with new bone forming the residual alveolar processes These become the residual ridges that are the foundation for dentures (a role for which they are ill-suited) What factors influence the rate of bone resorption? - correct answer Resorption has an exponentially reducing rate Females have greater bone resorption than males Diseases such as anemia can speed up the rate Where is resorption most rapid? - correct answer Anterior mandible Does a patient's periodontal status affect the status of their alveolar bone after they lose their teeth? - correct answer Yes! A healthy PDL maintains the integrity of alveolar bone What are the factors in denture retention? - correct answer Factors under doctor's control: 1. Optimal extension of denture base 2. Maxillary intimate contact of denture base to basal seat Other factors: muscular factors What is the Neutral Zone? - correct answer Specific area where the function of the musculature will not unseat the denture and where forces generated by the tongue are neutralized by the forces generated by the lips and cheeks. In other words, the zone where the orofacial and tongue muscles retain and stabilize dentures, ideally right on top of the bone Are complete dentures a good substitution of natural dentition for mastication? - correct answer No. Mastication helps appreciate the flavor of foods, is indirectly involved in the excitation of salivary and gastric secretions, and is important to the complete digestion of foods. CDs are not able to fully replace these functions. Why does denture movement occur? - correct answer Because of the dislodging forces of the surrounding musculature, which exposes the tissues to constant frictional contact These forces make CD's undergo displacement, lifting, sliding, tilting, and rotational movements What are parafunctional movements and what onsiderations need to be taken into account? - correct answer They are habits involving repeated or sustained occlusal contacts. These forces are frequently horizontal and vertical, as opposed to masticatory forces which are mainly vertical, and the forces are prolonged, possibly excessive, and both diurnal and nocturnal Clenching is common in denture wearers, with the patient complaining of soreness What are some of the initial discomforts associated with using new dentures? - correct answer Sore tongue from thrusting it against the CD to secure it Constant clenching until patient is confident and muscles adapt for retention Sore/tired lower lip when mandibular CD is not stable Sore mucosa due to decreased blood flow. Taking dentures off at night can help increase blood flow to the mucosa; blood flow helps slow down bone resorption Why do face height changes occur with edentulism? - correct answer Result of occlusal tooth surface loss Mainly due to attrition and abrasion of occlusal surfaces Residual ridge resorption decreases the total face height, resulting in mandibular prognathism, since the mandibular anterior ridge resorbs 4x faster than the maxillary anterior ridge What is the goal of preliminary edentulous impressions? - correct answer An overextended impression of the edentulous arch; recording all anatomical landmarks What are the disadvantages of alginate? - correct answer Does not readily displace soft tissues Easily displaced by soft tissues Not easily correctable Are rigid materials used for preliminary impressions? - correct answer Generally no, except to record atrophic mandibular edentulous ridges What are the advantages and disadvantages of impression (modeling) compound? - correct answer Advantages: thermoplastic, highly viscous (displaces soft tissues), best used for severely resorbed ridges, can be easily corrected Disadvantages: Not readily withdrawn and not withdrawn accurately from undercuts What does the color of impression compound identify? - correct answer Identifies melting temperature range White<gray<green<red<black What is retention? - correct answer Resistance to vertical displacement of the denture away from denture bearing surface during function What is support? - correct answer Resistance to vertical forces of occlusion. Factors of the bearing surface that resist or absorb occlusal loads during function. What is stability? - correct answer Resistance to lateral displacement of the denture during function. What are the 5 main factors that impact retention, support, and stability? - correct answer 1. Quality of oral mucosa 2. Alveolar ridge contour