robbypowell's version from 2016-11-30 04:11


REST 5001: Fixed Prosthodontics and Restorative dentistry
Clinical POLICIES and PROCEDURES Competency Exam
Note: All questions relate to techniques, procedures, or policies that are specific to the CDM. All answers relate specifically to the topic heading where the question appears. Rebekah: 52-68 Kayla: 69-85 Kristen: 86-103

Amalgam Restorations

Question Answer
What is the minimum thickness of tooth structure that must be maintained at the marginal ridge?1.5 mm
What is the purpose of the dovetail design in a Class II preparation?Retention (stop from moving inter proximally) (For a proximal slot restoration, retentive undercuts should be very distinct (at least 0.5mm deep) and should oppose each other to form a dovetail effect in the dentin. Long grooves, extending from the gingival floor to the occlusal surface, are recommended for a proximal slot restoration.)
What is the minimum thickness of Amalgam on the occlusal surface? Why is this necessary?2.0 mm; to resist fracture during function. (resistance form)
When is it necessary to use a secondary retentive feature in the box? Where is it placed?If the extension into the occlusal surface is narrow, if there is no extension into the occlusal surface, or if no amalgam bonding system is used, (retentive undercuts (grooves or points) must be cut into the dentin of the facial and lingual walls of the proximal box. So that retentive undercuts do not penetrate through the dentin to the DEJ when they are placed in the facial and lingual walls, they should be cut parallel faciolingually to the DEJ and to the external surface of the tooth.)
For a proximal box, what is the minimum clearance with the adjacent tooth?0.5 – 1mm gingival clearance
What is the difference between Tytin and Dispersalloy (composition, characteristics)?Dispersalloy is high copper, mixed particle type. Use small condensers, high force. Longer working time. Tytin is high copper, spherical particle type. Use large condensers, moderate force. Sets fast. Strengthen faster.
What is the most common cause of overhangs with amalgam restorations?Improper wedge placement; if the wedge is placed too far apically, it will not hold the band tightly against the gingival margin of the tooth.
What are the purposes (3) of placing a wedge while completing the preparation?1) Prewedging to open the contact with the adjacent tooth and to compensate for the thickness of the matrix band ... 2) Protect the rubber dam from damage and the gingival tissues from laceration... 3) To avoid adjacent tooth damage
What is the most likely cause of a void at the gingival margin of an amalgam restoration?Inadeqaute condensation pressure

Composite Resin Restorations

Question Answer
What happens to the color of composite resin when it is cured?It gets lighter.
How long after bleaching should you wait before placement of composite resins? Why (2 reasons)?Wait 2 weeks to allow the shade to stabilize. Also, composite resin to enamel bond strengths will be lower than normal if composite restorations are placed inside the two week post bleaching period. The two week wait allows the bond strength to return to normal.
What type of clamp is used for a Class V restoration? How is it stabilized?#212 clamp, stabilized with LC Blockout if necessary and the use of a cotton roll/gauze between the tooth and the clamp on the lingual.
What is the best way to remove an existing composite resin restoration to minimize tooth damage?High speed with water for bulk removal followed by slow speed without water in order to identify the composite resin.
What are the purposes of placing a bevel on a composite resin preparation (2)?1) More surface area for acid etching and bonding; 2) Enhances resin composite adaptation and seal of the gingival margin
For a Class V composite resin preparation (abfraction) which will have the gingival margin on the root and the incisal (occlusal) margin on enamel, what areas, if any, should be beveled?The gingival margin on the root should NOT be beveled. The incisal (occlusal) margin on enamel should be beveled. Should be beveled only if you are using composite, no bevel for RMGI
What is the maximum thickness of composite that should be applied in a single increment? Why?2mm to ensure proper light curing throughout the increment.
When should a void be repaired in a composite resin? Why?Immediately (best within 10 minutes) while the air inhibited layer is still present. Bond strength obtained after 24 hours is very poor.
When should bevels be used for glass ionomer restorations? Bevels are not needed on glass ionomer restorations. Bevels are used when placing composite and are only placed on enamel. Glass ionomer sets by a chemical acid-base reaction while composite has a micro-mechanical bond.
Describe the conditioning of dentin for a glass ionomer restoration.Cavity Conditioner is
 Polyacrylic Acid (PAA). (Used to condition the enamel & dentin prior to placing traditional or resin modified
 glass ionomers. Polyacrylic acid conditioner does not demineralize. It removes smear layer but not the smear plugs. Rinse polyacrylic acid conditioner & dry lightly. Dentin surface is shiny & reactive.)

Caries Management

Question Answer
Why should a patient requiring crown restoration because of carious lesions receive different follow-up care than one requiring crown restoration due to cusp fracture?More careful monitoring is needed to prevent recurrent decay under the crown. Patient should be kept on a short to med recall to evaluate effects of treatment and to review home care techniques.
Why is oral hygiene instruction alone not sufficient follow-up care for patients at risk of recurrent caries?Other factors could be involved such as diabetes, sjogrens, xerostomia, or substance abuse. (diet)
What are the methods (4) of caries detection?Tactile, transillumination, visual, radiographs
During the outline form phase of cavity preparation, would an explorer be the best method of checking for caries removal?No, (visualization is best assessment method (extension of outline form beyond ideal is determined by visual assessment of caries since both enamel caries and DEJ decay are hard and cannot be assessed by tactile methods. )
During the outline form phase of cavity preparation, should a cavity wall with a dark line at the DEJ, which is not soft to an explorer tip, be extended?Yes, (for the outline form, you should have a clean DEJ that you see visually. Caries at DEJ you will find visually. Caries on pulpal floor, you will find using tactile methods. )
During removal of carious dentin, would a caries disclosing dye be the best method of checking for caries removal?No, (although they may aid in the process. Caries dye stains infected, not affected dentin. It helps to find caries at the DEJ to make sure we remove unsupported enamel. Caries dye created false positives on the pulpal floor. )
Is carious enamel within a cavity preparation soft?No (it is white, opaque and hard)
During cavity preparation for a large carious lesion, why should the outline form be completed before removal of deep caries?To provide better access, visibility, and to expose all of the dentin caries. All unsupported enamel needs to be removed.
How should a large area of carious dentin which threatens the pulp be removed? Indirect pulp capping-remaining softened dentin is covered with calcium hydroxide (Dycal) and the area is restored with temporary material, which is removed 6-8 wks later and a definitive restoration is placed.

Core Build-up Restorations (Foundations) for Vital Teeth

Question Answer
Considering the risk of failure due to dislodgment, what is the most important factor determining the success of a vital tooth foundation?Failures due more to poor design than poor technique. Proper design is the the most important factor.
Why is it important to extend the crown preparation apical to the core (2 reasons)?To obtain adequate dentin ferrule (important for retention, resistance, and most important to minimize risk of dislodging the core) and to minimize micro-leakage at the core-tooth interface (minimize risk of decay).
What is the concern regarding the use of chemically-cured core resins and self-etching dentin bonding agents? “CompCore” Limitations: Chemically(dual) cured resins
 incompatible with self-etching adhesives (+ some single bottle); too acidic for polymerization. Another concern is manufacturer incompatibilities.
Describe the DBA (type, brand) and technique for use with chemically-cured core resins (e.g. CompCore).Auto-cured (means to be chemically cured) Brand: IntegraBond. Technique: Etch, rinse, dry (do not desiccate), (Mix primer/adhesive with auto-cure material (one in each bottle), apply to tooth with microbrush, dry, light cure 20 sec, place restoration. )
Which two pin sizes are recommended for routine use (name, size, color)?Minim, 0.6 mm, silver (grey) and Minikin, 0.5 mm, red
Explain the 2-2-2-2 rule for retentive pins.2 mm pinhole depth, 2 x drill width (1 mm) inside DEJ, 2 mm pin length, 2 mm rest mat over top of pin
What is the rule of thumb for the number of pins for a vital tooth foundation?One per line angle.
What are the 2 important principles for the proper use of the slow-speed handpiece when drilling pin holes?1.)Use gear down in slow speed handpiece. 2.) Drill in forward, in and out in 1 time.
What is the proper location and orientation of the twist drill when preparing the pin hole?parallel to external surface of tooth
Why are glass ionomer restorative materials a poor choice for large core build-up restorations?Glass ionomer disadvantages include solubility and low strength. They are only acceptable for for block-out of undercuts, not for the core.
Why should large composite resin restorations be used as the core or foundation for a cast restoration only when the definitive restoration is certain to be placed relatively soon?Composite resin core advantages include strength, dentin bonding, and may be prepared immediately. Amalgam has low early strength and cannot be prepared immediately.
Why would an Amalgabond-retained amalgam be a poorer adhesive core build-up restoration than an adhesive resin composite?Amalgabond is helpful, but does not replace mechanical retention; can reduce sensitivity and microleakage. Amalgabond only bonds with minimal strength to tooth.

Diagnosis & Treatment Planning for Indirect Procedures

Question Answer
What are the reasons (7) for crowning a tooth?minimal remaining clinical crown due to caries/fracture, protection of endodontically treated teeth (posterior), cracked teeth which are symptomatic, correction of unfavorable plane of occlusion, surveyed crowns for RPD, recurrent decay on existing large restoration, esthetics
What are the risks (5) associated with restoring a tooth with a crown?pulpal trauma, need for new foundation, need for RCT and P and C if retention cant be obtained for foundation, need for crown lengthening to prepare finish line apical to existing restoration, recurrent caries, porcelain fracture
What are the treatment options (3) for a patient with an edentulous space bounded by natural teeth?implant, bridge, removable
How should the dental chair be positioned for a clinical occlusal exam?patient supine
How is the horizontal condylar guidance set on the articulator?A protrusive record, or 2 lateral records
What are the purposes (3) for BW x-rays prior to indirect treatment? What are the purposes (4) for PA x-rays prior to indirect treatment? Why is occlusal porcelain usually contraindicated for mandibular 2nd molars (2 reasons)?1.)Short clinical crowns make it difficult to provide adequate wall height (>3mm) following the required 2mm of occlusal reduction. 2.) Greater risk of porcelain fracture with the most distal tooth in arch.
Tooth Preparation for Crowns (answers taken from FIXP 5001 and FIXP 5002 lectures)
Question Answer
How much occlusal reduction is required for a gold crown? For a PFM crown?Gold: 1.5mm PFM: 2mm
How much incisal reduction is required for an anterior PFM crown?2mm


Question Answer
What is the margin design for a gold crown (name, dimension, and geometry)? What bur is used to prepare this margin?A definite chamfer (0.5 mm) is present at all cavosurface margins.
Comparing a PFM crown to a FG crown for a posterior tooth, which preparation criteria are the same?Proximal & lingual reduction, proximal & lingual margins. (Facial & occlusal reduction are different, but I accepted most any answer for this question)
Why does a lipped margin usually result in a poor marginal fit?Bubbles on margin of die, Fracture of die margin, Abrasion of die margin during waxing, Fracture of unsupported enamel at cementation
What bur is used to break the proximal contact?Proximal reduction is completed with a small diameter bur… small chamfer bur
What are the requirements for resistance form for a crown preparation?axial wall should be 3-4 mm long and each wall should have 6- 8 degree taper
Why should all molar preparation have grooves? Where should the grooves be placed?All molars should have grooves because they naturally lack adequate resistance form. I think there was something about arc of rotation or something like that we learned the reason for the groove aka decrease arc of rotation

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