Final corrected 16-17 Operative (2)

goldIf a lab is getting a high occurrence of surface nodules on the castings they make,what might you suspect about their investing process?• They are vacuum-investing• They are hand-investing• Nothing in particular, hand- and vacuum-investing are the same thing• None of the above 75 copyright © 2016-2017 Dental DecksOPERATIVE

• They are hand-investingThese defects, or nodules, are caused by the collection of air bubbles during theinvesting procedure. The best way to help eliminate these defects is to subject the water-investment mixture to a vacuum during the investing procedure to remove the air bubbles.The porosity of the investment is definitely reduced by vacuum-investing, presumablybecause of the increased density obtained. As a result, the texture of the surface of thecasting is somewhat smoother, with better reproduction of fine detail. The compressivestrength of the investment is increased slightly by the vacuum investment (the invest-ment will not fracture as easily).Not all of the air is removed by the vacuum treatment. The amount removed dependssomewhat on the consistency of the mix. The more viscous the mix, the more airbubbles remain in the investment. However, a thick mix is usually necessary because ofthe desired shrinkage compensation and because of the poor surface texture that isobtained with a thin mix.

goldYou are preparing tooth #19 for a MODB gold onlay and tooth #18 for a MODBamalgam restoration. Which of the following TWO statements correctly describethe difference in your preparations of the functional cusp?• You will need 2.5 to 3 mm of reduction for gold• You will need 2.5 to 3 mm of reduction for amalgam• You will need 1.5 mm of reduction for gold• You will need 1.5 mm of reduction for amalgam 76 copyright © 2016-2017 Dental DecksOPERATIVE

• You will need 2.5 to 3 mm of reduction for amalgam • You will need 1.5 mm of reduction for goldRemember: Non-working cusps (non-supporting) Working cusps (functional cusps) • Maxillary teeth: buccal • Maxillary teeth: lingual • Mandibular teeth: lingual • Mandibular teeth: buccal Minimal Occlusal Reduction Cusp Amalgam Cast Gold Metal-Ceramic Working 2.5-3.0 mm 1.5 mm 2.0 mm Non-working 2.0 mm 1.0 mm 1.5 mmNotes 1. For non-working cusps the minimal reduction for amalgam is 2.0 mm while forming a flattened surface (this provides resistance form) and, for cast gold, it is 1.0 mm. 2. For metal-ceramic restorations: facial and lingual reduction — 1.5 mm 3. The difference between tooth preparation for a metal-ceramic restoration and a porcelain jacket crown is mostly related to the configuration of the finishing line or margin —chamfer or bevel for metal-ceramic restorations and a butt joint for porcelain jacket crowns.Important: The most effective means for verifying adequate occlusal clearance is a waxbite chew-in.

instruments/bursThe modified pen grasp is the most common instrument grasp in dentistry;this is because it allows for the greatest intricacy and delicacy of touch.• Both the statement and the reason are correct and related• Both the statement and the reason are correct but not related• The statement is correct, but the reason is not• The statement is not correct, but the reason is correct• Neither the statement nor the reason is correct 77 copyright © 2016-2017 Dental DecksOPERATIVE

• Both the statement and the reason are correct and relatedWith this grasp, the middle finger, index finger, and thumb all rest on the handle close tothe junction of the handle and the shank. The middle finger rests on the shank, and thethumb and index finger are opposite each other on the handle. (See picture below)The inverted pen grasp is very seldom used, however, sometimes it is used for cavitypreps utilizing the lingual approach on anterior teeth.The palm and thumb grasp is the most powerful grasp and is most effectively used onthe maxillary arch. It is similar to the grasp used for holding a knife while paring the skinfrom an apple.The modified palm and thumb grasp allows much of the power of the palm and thumbgrasp but also permits more delicate control. It works best when you can rest the thumbon the tooth being restored or on the adjacent tooth. It also works best on the maxillaryarch.

instruments/bursSoft materials, such as acrylics, are cut most effectively with:• Zero rake angle burs• Positive rake angle burs• Negative rake angle burs 78 copyright © 2016-2017 Dental DecksOPERATIVE

• Positive rake angle burs*** Remember: The rake angle = the angle made between the line connecting the edge of the blade to the axisof the bur and the rake face. This angle may be positive or negative.Generally speaking, soft materials, such as acrylics, are cut most effectively with positive rake angle burs;whereas extremely hard and brittle materials (such as amalgam) are best cut with negative rake angle burs.A rake angle is said to be negative when the rake face is ahead of the radius (from the cutting edge to the axisof the bur). A negative rake angle minimizes fractures of the cutting edge that helps to increase the bur life.Increasing the edge angle reinforces the cutting edge of the bur and reduces the likelihood of the blade tofracture.Carbide burs used for cutting tooth structure generally have slight negative rake angles and edge angles ofapproximately 90°. To be most effective, these burs should be rotating rapidly before contacting the tooth.The clearance angle is also another important factor in blade design. The clearance angle serves to eliminatefriction between the clearance face and the new tooth structure exposed by the cutting edge. The greater theclearance angle, the less friction. Rake To Axis of Bur angleReproduced with Edge Angle Bur blade design. Schematic cross sec-permission, from tion viewed from shank end of head toSturdevant CM, Rober- show rake angle, edge angle, and clear-son TM, Heymann HO, ance angle.and Sturdevant JR.The Art and Science of ClearanceOperative Dentistry, angleThird Edition. Mosby,1995. Rake face Clearance face Direction of Rotation SchematicAll of the following factors influence tooth temperature during a cutting procedure:• Diameter and sharpness of the bur• Bur/tooth contact time• Type of coolant used (water is best, air may dehydrate the tooth or cause the tooth to be hypersensitiveby drawing odontoblasts into the dentinal tubules)• Amount of force applied to the bur

instruments/bursThe ___________ angle is the angle formed between the ___________ face andthe ___________ face.• edge, rake, clearance• rake, edge, clearance• clearance, rake, edge 79 copyright © 2016-2017 Dental DecksOPERATIVE

• edge, rake, clearanceEach bur blade has two sides: 1. The rake face (toward the direction of cutting) • The rake face is the surface (side) of the blade that makes contact with the tooth surface and faces in the direction of bur rotation. 2. The clearance face • The clearance face is the surface (side) of the blade that faces away from the di- rection of bur rotation.Each bur blade has three important angles: 1. The rake angle • The rake angle is the angle made between the line connecting the edge of the blade to the axis of the bur and the rake face. This angle may be positive or negative. 2. The edge angle • The edge angle is the angle formed between the rake face and clearance face. 3.The clearance angle • The clearance angle is the angle formed between the clearance face and a tangent to the path of rotation.Note: For most effective cutting, a bur should be rotating rapidly before contacting thetooth.

instruments/bursWhat is the blade length of a cutting instrument with the following formula:10 - 85 - 8 -14• 10 mm• 1.0 mm• 0.85 mm• 8.0 mm 80 copyright © 2016-2017 Dental DecksOPERATIVE

• 8.0 mmCutting instruments have formulas describing the dimensions and angles of the working end: • The first number indicates the width of the blade in tenths of a millimeter — 1.0 mm (10 x .1) for the example on the front of the card. • The second number indicates the primary cutting edge angle in centigrades — 85 for the exam- ple on the front of the card. • The third number indicates the blade length in millimeters — 8 mm for the example on the front of the card. • The fourth number indicates the blade angle in centigrades — 14 for the example on the front of the card.Three major parts of a hand-cutting instrument: 1. The handle is that part of the instrument held or grasped during activation of the blade. Types: single-ended or double-ended. 2. The shank serves to connect the blade to the handle. Types: straight or angled (mon-angle, bi- angle, or triple-angle: meaning one, two or three angles in the shank). Note: Proper balance of the instrument is accomplished by angling the shank of the instrument so that the cutting edge of the blade is within 2 mm of the long axis of the handle. To keep the blade within 2 mm of the long axis, the shank of the instrument is angled. 3. The blade is the working end of the instrument and is connected to the handle by the shank. Blades are of many designs and sizes, depending on the function they are to perform.*** The nib is not a major part of a hand cutting instrument. It is the working end of a non-cuttinginstrument (i.e., a burnisher, condenser, etc.). The end of the nib, or working surface, is known as theface. Note: It corresponds to the blade of a hand cutting instrument.

instruments/bursChisels are used primarily to cut dentin.Hatchets are primarily used to cut enamel.• Both statements are true• Both statements are false• The first statement is true, the second is false• The first statement is false, the second is true 81 copyright © 2016-2017 Dental DecksOPERATIVE

• The first statement is false, the second is true*** Chisels are also primarily used to cut enamel Chisels may be grouped as: 1. Straight, slightly curved, or bin-angle: primarily used for planing or cleaving enamel. Characterized by a blade that terminates in a cutting edge formed by a one-sided bevel. 2. Enamel hatchets: are chisel-bladed instruments with the cutting edge in the plane of the handle. They come paired left and right. 3. Gingival margin trimmers: are similar in design to the enamel hatchet except it has a curved blade and an angled cutting edge. They are primarily used for beveling gingival margins. Among other uses for these in- struments is the rounding or beveling of the axiopulpal line angle of Class II preparations (very important). Bin-angle WedelstaedtChisels Straight Bi-beveled Mono-beveledHatchets

instruments/bursMatch the type of excavator on the left with the main purpose on the right.• Hoes Sharpening line angles and convenience points for gold foil preps• Angle formers Preparing retentive areas on anterior teeth• Ordinary hatchet Remove carious dentin and sometimes carve amalgam• Spoons Class III and V direct gold preps 82 copyright © 2016-2017 Dental DecksOPERATIVE

There are four subdivisions of excavators: 1. The hoe excavator: has the cutting edge of the blade perpendicular to the axis of the handle. It is commonly used in Class III and V preps for direct gold. 2. The angle former: has the cutting edge at an angle (other than 90°) to the blade. It is used for sharpening line angles and is especially useful to form convenience points for gold foil preps. 3. An ordinary hatchet excavator: has the cutting edge of the blade directed in the same plane of the handle and is bi-beveled. Used primarily on anterior teeth for preparing retentive areas. 4. A spoon excavator: has a curved blade with a rounded cutting edge. It is used to remove carious dentin and sometimes to carve amalgam. Note: These can be sharpened with handpiece stones.

instruments/bursYou set down the hand piece after preparing a Class II amalgam on tooth #4.Your assistant hands you a _______________ so you can remove the last bit ofcaries, and then the ____________ so you can plane the facial and lingual wallsof the prep.• spoon excavator, enamel hatchet• spoon excavator, straight chisel• gingival margin trimmer, enamel hatchet• gingival margin trimmer, straight chisel 83 copyright © 2016-2017 Dental DecksOPERATIVE

• spoon excavator, enamel hatchet*** The enamel hatchet is the only instrument that will allow the dentist to have proper access tothe margins and that will impart the proper cavosurface angle to the margins.Spoon excavators are used for removing caries and carving amalgam or direct wax patterns. Theblades are slightly curved, and the cutting edges are either circular or claw-like. The circular edgeis known as a discoid, whereas the claw-like blade is termed a cleoid (see picture below).Theshanks may be bin-angled or triple-angled to facilitate accessibility. discoid cleoidThe number of bevels that make up the cutting edge can classify hand cutting instruments. Forexample, enamel hatchets and chisels have single bevels, whereas ordinary hatchets (for example,excavators) have two bevels and are called bi-beveled.Dental hand cutting instruments are angled to: • Provide better manipulative control • Produce a better distribution of force • Increase efficiency • Establish proper balance when in useInstruments used to trim restorative materials rather than for cutting tooth structure: • Knives (finishing, amalgam, or gold): used for trimming excess filling material on the facial and lingual • Files: also used to trim excess filling material, especially at the gingival margins • Discoid-cleoid: used principally for carving occlusal anatomy in unset amalgam restorations

instruments/bursTo polish a restoration, you will likely use a bur with less cutting blades. This isbecause a bur with less cutting blades will cut more efficiently.• Both the statement and the reason are correct and related• Both the statement and the reason are correct but not related• The statement is correct, but the reason is not• The statement is not correct, but the reason is correct• Neither the statement nor the reason is correct 84 copyright © 2016-2017 Dental DecksOPERATIVE

• The statement is not correct, but the reason is correct*** Important: The greater the number of cutting blades on a bur results in less efficient cutting but a smoothersurface (polishing burs are of this type). A lesser number of blades on a bur results in more efficient cutting but arougher surface. Crosscut fissure burs at high speed or low speed are of this type.Parts of burs: 1. Shank: the part that fits into handpiece. The three most common types are straight, latch-type angle, and friction-grip angle. 2. Neck: the intermediate portion of a bur that connects the head to the shank. Its main function is to transmit rotational and translational forces to the head. 3. Head: the working part of the bur, the cutting edges perform the desired shaping of tooth structure.Types of burs: • Steel (used mostly for finishing procedures) • Carbide (used for cavity preparation; perform best at high speeds)Shapes of burs: refers to the contour of the head. The basic head shapes are round, inverted cone, pear, straightfissure, and tapered fissure. Note: Within a given series of burs, the smaller numbers represent small burs; the largernumbers, large burs.Recent modifications in bur design: • Reduced use of crosscut burs — non-crosscut burs are now popular • Carbide fissure burs with extended heads • Rounding of the sharp tip cornersThe rotational speed of an instrument is measured in revolutions per minute (rpm). There are 3 speed ranges: slow(below 12,000 rpm), intermediate (12,000 to 200,000 rpm), and high (above 200,000 rpm) speed. The most usefulinstruments are rotated at either low or high speed. The crucial factor for some purposes is the surface speed of theinstrument - the velocity at which the edges of the cutting instrument pass across the surface being cut. This isproportional to both the rotational speed and the diameter of the instrument, with large instruments having highersurface speeds at any given rate of rotation.Diamond abrasive instruments: involve abrasive rather than blade cutting. These instruments are based on small,angular particles of hard substances held in a matrix of softer material. Diamonds consist of three parts: a metal blank,the powdered diamond abrasive, and a metallic bonding material that holds the diamond powder onto the blank. Theblank, in many ways, resembles a bur without blades. It has the same essential parts: head, neck, and shank. Theclinical performance of diamonds depends on the size, spacing, uniformity, exposure, and bonding of the diamondparticles. Diamond particle size is commonly categorized as coarse, medium, fine, and very fine.

miscellaneousThere are several types of bleaching products available for use at home,which can either be dispensed by a dentist or purchased over-the-counter.Currently, only dentist-dispensed home-use _______________tray-appliedgels carry the ADA Seal of Acceptance.• 30% carbamide peroxide• 15% hydrogen peroxide• 20% hydrogen peroxide• 10% carbamide peroxide 85 copyright © 2016-2017 Dental DecksOPERATIVE

• 10% carbamide peroxideTwo methods of bleaching: 1. “In-office”: most use a light-activated solution of 35% hydrogen peroxide in 4 to 10 minute cycles. This procedure is called “chairside bleaching” and may require more than one office visit. Each visit may take from 30 minutes to 1 hour. Note: Lasers have been used during tooth whitening procedures to enhance the action of the whitening agent. 2. “At-home”: the active ingredient contained in all of the at-home tooth whiteners which have earned the ADA's seal, and the compound which has been evaluated in the vast majority of at-home bleaching studies, is carbamide peroxide at a concen- tration of 10%. The active ingredient found in most over-the-counter at-home bleach- ing products is not carbamide peroxide, but instead is hydrogen peroxide.Note: Bleaching can affect the color of dentin and enamel. Extrinsic stains respond bestto vital beaching. Response is best with yellow stain followed by brown and orange. Theworst response is from gray stains (tetracycline staining).Other ways to lighten vital teeth: • Direct composites: useful for tetracycline staining • Laboratory-fabricated porcelain veneers: useful when the shape, size, and arrange- ment of teeth are esthetically unacceptable • Full-coverage crowns (most invasive and costly): may be all-ceramic or porcelain fused to metalNote: The placement of composite restorations should be delayed at least a week afterbleaching otherwise composite bonding can be compromised.

miscellaneousAll of the following are a zone in four-handed dentistry EXCEPT one. Whichone is the EXCEPTION?• Operator zone• Assistant zone• Transfer zone• Patient zone• Static zone 86 copyright © 2016-2017 Dental DecksOPERATIVE

• Patient zoneThe operator and the assistant should concentrate on positioning themselves in work circles. Thedentist's work circle should allow easy and unobstructed access to the patient's mouth. The assis-tant's work circle should include all instruments and supplies needed for the intended operation, alsoallowing access to the transfer zone to bring the necessary items to the dentist. When viewed fromabove with the patient's head in the 12:00 o'clock position, the right handed dentist will operate inan area from 7:00 to 12:00 o'clock. This area is the operator’s zone. Nothing should be in this areathat would interfere with the free movement of the dentist. The area from 12:00 to 2:00 o'clock iscalled the static zone. This area is reserved for the mobile cabinet and nitrous oxide apparatus.The area from 2:00 to 4:00 o'clock is the assistant's zone. Although the assistant will not move asmuch as the dentist, nothing should be positioned in this area that would hamper the assistant'sfree access to the oral cavity, mobile cabinet, and dental unit. The area form 4:00 to 7:00 o'clock is thetransfer zone. This area is reserved for the transfer of instruments, medicaments, and supplies to the den-tist. Also, the dental unit should be positioned within this arc. Zones of Activity for a right-handed dentistOther considerations for an efficient four-handed dental delivery system: • Concerning the transfer of instruments: the hand instrument to be transferred to the dentist is held by the assistant between the thumb and the forefinger. • Equipment selection: whatever equipment is used, it should be compatible for the dentist and assistant. The position of the chairside assistant should be higher than the dentist.Note: Venting the suction exhaust to the building exterior can reduce health hazards to the office stafffrom the central suction unit.

miscellaneousXerostomia is the most common adverse side effect of medications.This is attributed to the cholinergic effects of many medications.• Both statements are true• Both statements are false• The first statement is true, the second is false• The first statement is false, the second is true 87 copyright © 2016-2017 Dental DecksOPERATIVE

• The first statement is true, the second is false*** This is attributed to the anticholinergic effects of many medications.Other etiologic factors for xerostomia include: • Radiation therapy to head and neck • Salivary gland surgery • Autoimmune disorders, such HIV infections, systemic lupus erythematosus, rheuma- toid arthritis, and Sjögren syndrome • Endocrine disorders, such as diabetes and hyperthyroidismSalivary flow rates (normal): • Unstimulated ~ 0.3-0.5ml/min • Stimulated ~ >1ml/min https://www.dentistry.iu.edu/OHCCP/_pdf/dry_mouth_fact_sheet.pdfTreatment for xerostomia: • Consider stopping offending medication (at the discretion of the patient’s physician) • Commercial saliva substitute • Fluoride supplementation • Scrupulous dental care is essentialAnticholinergic drugs (which block receptor sites for acetylcholine) decrease salivaryflow and respiratory secretions during surgery. Examples include: atropine, scopolamine,methantheline, and propantheline bromide.Don’t forget: Local anesthetics aid in reducing the flow of saliva during operative pro-cedures by reducing sensitivity and anxiety during tooth preparation.Remember: Cholinergic agents actually increase secretions; a cholinesterase inhibitorwould also increase secretions because it would reduce the metabolism of acetylcholine.

miscellaneousWhen restoring a Class II or Class III lesion, it is important to create properlyshaped embrasures for all of the following reasons EXCEPT one. Which one isthe EXCEPTION?• Create a spillway for food during mastication• Make the teeth self-cleansing• Protect the gingival tissue, while also allowing stimulation of it• Provide arch stability 88 copyright © 2016-2017 Dental DecksOPERATIVE

• Provide arch stability*** As long as a contact is present, regardless of proper embrasure contour, you willmaintain arch stabilityThere are four embrasures for every contact area: 1. Buccal (or facial) 2. Lingual (usually larger than the facial) 3. Occlusal (or incisal) 4. Cervical (or gingival) *** Note: In posterior teeth, the gingival tissue fills this embrasure. Normally it is \"col\" shaped when viewed in a faciolingual cross section.Functions of embrasures: 1. Make a spillway for food during mastication 2. Make the teeth more self-cleansing 3. Protect the gingival tissue from undue frictional trauma, but at the same time pro- vide the proper degree of stimulation to the tissue.A contact area is an area in which the mesial and distal surfaces of adjacent teeth in thesame arch make contact. A contact point is a point at which teeth of the opposing archesmeet or touch in occlusion or closure.The height of contour refers to the thickest portion or point of greatest circumference ofthe tooth when viewed from the incisal or occlusal surface. Its functions include formingthe contact area on the mesial and distal surfaces and protecting the gingiva surroundingthe tooth.

miscellaneousA tooth was restored 3 months ago by a new associate of yours. The patient iscomplaining of mobility and thermal sensitivity. You take a periapical radio-graph. You could see all of the following in that radiograph to confirm yoursuspicions, EXCEPT one. Which one is the EXCEPTION?• Hypercementosis• Root resorption• Periodontal pockets• Alteration of the lamina dura• Widening of the periodontal ligament space 89 copyright © 2016-2017 Dental DecksOPERATIVE

• Periodontal pockets*** You should have suspected that the restoration was high, based mainly on the mobilityfactor. Occlusal trauma can still cause periodontal pocketing; however, that cannot beseen on a radiograph.Some common clinical signs of trauma from occlusion include: • Increased tooth mobility is the most common clinical sign • Thermal sensitivity (cold): presumably, this sensitivity is due to venous hyperemia of the tooth • Attrition of the enamel • Recession of the facial gingival tissueRemember: Whenever a restoration is done, the occlusion has to be right. The degree ofcontact on the restoration should be to the same degree that teeth contact in that quadrantand on the opposite site.Note: The radiograph of choice for evaluating root surfaces, supporting bone, and theperiodontal ligament is the periapical film.

miscellaneousWhen restoring the embrasures of posterior teeth, the contact should be formedslightly buccal from center.This will create a wider facial embrasure.• Both statements are true• Both statements are false• The first statement is true, the second is false• The first statement is false, the second is true 90 copyright © 2016-2017 Dental DecksOPERATIVE

• The first statement is true, the second is false*** This will create a wider lingual embrasure and a narrow facial embrasure.The primary purpose of the proximal contact relationships between adjacent teeth in thedental arches is twofold. This relationship serves both to stabilize the dental arches by thecombined support of the individual teeth and to prevent the impingement of foodmaterial on interseptal tissues between the teethThe proximal contact area functions to: 1. Support neighboring teeth (stabilizes the dental arch) 2. Prevent food particles from entering the interproximal areas 3. Protect the periodontium 4. Form embrasuresThe loss of proximal contact between teeth may result in periodontal disease, malocclu-sion, food impaction, or drifting of teeth.Remember: When viewed from the facial, all premolars have their contacts at thejunction of the occlusal and middle third. From this same view, molars have aproximal contact located in the middle third. From the occlusal view, all posterior teethhave contacts that are located slightly buccal of the middle third (mesial and distal).This creates a wide lingual and a narrow facial embrasure.

miscellaneousA patient presents to your office complaining of pain upon biting on her lowerright side. Upon examination, the offending tooth appears to have disto-occlusalclinical caries. The patient reports a positive response to cold testing lasting 12seconds. The pulpal diagnosis is:• Normal pulp• Reversible pulpitis• Irreversible pulpitis• Pulpal necrosis 91 copyright © 2016-2017 Dental DecksOPERATIVE

• Reversible pulpitisPulpal necrosis is the death of the pulp. A tooth affected with a necrotic pulp may haveno painful symptoms. It may appear discolored. The EPT (electric pulp tester) will be ofvalue because there will be no response at any current level. The tooth sometimesresponds to heat but will not respond to cold. Treatment is root canal or extraction.Note: Symptomatic apical periodontitis is characterized by pain, which is commonlytriggered by chewing or percussion. Symptomatic apical periodontitis alone is notindicative of an irreversible pulpitis. It indicates that the apical tissues are irritated, whichmay be associated with an otherwise vital pulp with a potentially reversible pulpitis. In theabsence of acute pain, a negative EPT test, or a frank apical radiolucency, a carious toothwith sensitivity to percussion may respond to caries control (temporary filling). If itdoesn’t respond to a sedative filling, root canal is indicated.Pulpal Diagnosis Cold Response TreatmentNormal pulp Not delayed or very short linger None neededReversible pulpitis Lingers less than 10-15 seconds Remove causative agentSymptomatic Lingers longer than 15 seconds RCT or extractionIrreversible pulpitisPulp necrosis No response RCT or extraction

miscellaneousOn the first day in your solo private practice, you have a pulp exposure. Whichof the following are favorable factors in avoiding root canal treatment?Select all that apply.• It is a mechanical exposure of 1 mm• The tooth had never been symptomatic• The pulp tissue appears pink• The hemorrhage is severe• It is a pinpoint carious exposure 92 copyright © 2016-2017 Dental DecksOPERATIVE

• It is a mechanical exposure of 1 mm • The tooth had never been symptomatic • The pulp tissue appears pinkDirect pulp capping involves the prompt application of a setting calcium hydroxide cement to a“pinpoint” (less than 1 mm in diameter), well-isolated traumatic pulpal exposure. This proceduremay be expected, in most instances, to stimulate the formation of a reparative \"dentin bridge\" overthe exposure site and to preserve the underlying pulpal tissue in a healthy condition.Favorable factors for direct pulp capping include: the visual evidence of uninflamed (pink) pulptissue, the absence of copious hemorrhage through the exposure, no previous symptoms ofpulpitis, a small noncarious exposure (a mechanical pulp exposure), and a clean cavityuncontaminated with saliva.The following adverse responses may occur following direct pulp capping procedures: • Physical or microbial insult to the pulp may result in persistent inflammatory changes, which may culminate in partial or complete pulpal necrosis. • Regulation of the mineralization processes involved in dentin bridge formation may become deranged, resulting in extensive calcification and obliteration of the pulp canal space by mineralized tissue. • Very rarely, the differentiation of odontoclasts may be induced with the development of internal resorptive lesions.Notes 1. Direct pulp capping is especially successful in immature teeth. 2.The failure of this direct pulp capping procedure would be indicated by symptoms of pulpitis at any time or the lack of a vital response after several weeks or months. 3. Direct pulp capping should not be attempted on teeth with a history of pain, sensitivity to percussion, or periapical radiolucencies (root canal therapy may be indicated). 4. Direct pulp capping is generally not performed on primary teeth.

miscellaneousThe ideal amount of time from placing an indirect pulp cap until reopening thetooth to remove the remaining decay is:• 7 - 10 days• 2 - 3 weeks• 1 month• 3 - 4 months• 1 year• Never, unless the tooth becomes symptomatic there is no need for further treatment 93 copyright © 2016-2017 Dental DecksOPERATIVE

• 3 - 4 monthsTwo types of pulp capping procedures: 1. Indirect pulp cap: a calcium hydroxide base is placed on a thin layer of question able dentin remaining over the pulp. It is performed when a carious exposure is antic- ipated. After a 3- to 4- month waiting period, the tooth is reopened and the remaining decay is removed. During the waiting period, it is hoped that there will be secondary dentin formation, allowing complete removal of the decay without pulp exposure. Classic example: A radiograph of a first molar shows gross decay that may involve a horn of the dental pulp. The ideal treatment would be to do an indirect pulp cap and place a sedative filling (IRM). If tooth remains asymptomatic, in 3 to 4 months you can reenter the tooth and remove all decay with subsequent placement of a permanent filling. Note: If this patient had pain in the tooth (aggravated by heat and tender to percussion), and excavation of the carious lesion revealed exposure of the pulp horn without evidence of vital tissue, the emergency treatment pending eventual root canal therapy is to place a small cotton pellet dampened with eugenol over the expo- sure and seal the cavity with a temporary material (IRM).Rationale for indirect pulp capping — there are three dentinal layers in a carious lesion: 1. A necrotic, soft, brown dentin outer layer, teeming with bacteria. 2. A firmer, discolored dentin layer with fewer bacteria. 3. A hard, discolored dentin deep layer with a minimal amount of bacterial invasion. 2. Direct pulp cap: a calcium hydroxide base is placed directly on a pulpal exposure.

miscellaneousA patient walks into your office for an emergency visit. He asks the receptionistfor a cold glass of water and seems to be tilting his head sideways as to hold thewater on one side of his mouth. Immediately, you suspect which reason for hisvisit?• Pulp necrosis• Reversible pulpitis• Symptomatic irreversible pulpitis• Asymptomatic apical periodontitis 94 copyright © 2016-2017 Dental DecksOPERATIVE

• Symptomatic irreversible pulpitisSymptomatic irreversible pulpitis is a clinical diagnosis based on subjective and objectivefindings indicating that the inflamed pulp is incapable of healing. Additional descriptorsinclude lingering thermal pain, spontaneous pain, and referred pain. In the early stages, it mayappear as just a sensitive tooth. As the condition continues, the pain may be described as agnawing or dull throbbing. The treatment accepted by most clinicians is pulp removal (rootcanal therapy). Note: The tooth is usually percussion-positive.At first, the pain is initiated and sustained only by the stimulus (this is reversible pulpitis).Later, as the pulpal swelling spreads from the initial area of damage or irritation to the rest ofthe pulpal tissue in the chamber, the pain initiated by the stimulus becomes more prolonged(this is symptomatic irreversible pulpitis). If enough pulpal tissue becomes damaged, the painmay initiate or persist without any stimulus at all. At the same time, the degenerativeinflammation of the pulp may reach down the entire length of the root or roots and begin tocause the apical PDL to become inflamed (symptomatic apical periodontitis). Now the patientmay have not only a throbbing toothache but also pressure sensitivity (to the pressure ofchewing or percussion). This stage marks a later point in the pulpal degenerative timelinewhen the tooth is the “hottest” and usually the most difficult to get numb.Important: Sometimes it is hard to distinguish between reversible and irreversible pulpitis,in which case caries control (the placement of a temporary filling) is a conservative approachtoward making the final diagnosis. If a tooth responds well to this temporary filling, then theneed for root canal therapy at this time is ruled out.Remember: Reversible pulpitis is a clinical diagnosis based upon subjective and objectivefindings indicating that the inflammation should resolve and the pulp should return to normal.Once the causative agent (i.e., bacteria or a restoration in hyperocclusion) is removed oradjusted, the pulp will most likely return to normal.

miscellaneousA cold test reveals a lingering pain. You ask the patient to raise her hand until thepain subsides. The patient raises her hand for about 8 seconds. What does thisdata suggest?• Pulp necrosis• Symptomatic irreversible pulpitis• Reversible pulpitis• Symptomatic apical periodontitis 95 copyright © 2016-2017 Dental DecksOPERATIVE

• Reversible pulpitisReversible pulpitis and may be caused by physical, chemical, or bacterial insult.Following restoration placement, teeth often become hyperemic and are sensitive to coldfor a few days. The pain is not spontaneous and does not last longer than approximately10 seconds after the stimulus is removed. It is this fact, its short duration and lowintensity, that distinguishes it from the pain of symptomatic irreversible pulpitis.Remember: Teeth that are diagnosed as having a reversible pulpitis respond on a lowerlevel of current on the EPT (electric pulp tester) than a normal tooth.Treatment: If possible, the source (e.g., high restoration) should be removed. Ifindicated, a sedative restoration can be useful. If due to deep caries, an indirect pulp capshould be used only in permanent teeth and when pulp pathology is believed to bereversible (e.g., no periapical pathology, no lingering spontaneous pain that might beworse overnight, and stimulated pain of short duration only).Important: Reversible pulpitis caused by bacterial insult is a limited inflammation ofthe pulp. The tooth can recover if the caries is eliminated by timely operative treatment.When the pulp becomes severely inflamed, as indicated by a thermal stimulusproducing pain that lasts long after the stimulus is removed (longer than 15 seconds), thissuggests “symptomatic irreversible pulpitis.” The pulp is unlikely to recover afterremoving the caries.Remember: The most effective way to reduce injury to the pulp during tooth preparationis to use adequate irrigation to avoid heating of the dentin.

pinsWhat was previously an MOD amalgam in #20 now shows that the entirelingual portion of the tooth has fractured off. You believe that the tooth isrestorable with a pin-retained amalgam restoration/core. How many pinswill you likely use and why?• One, because you are missing the lingual cusp only• Two, because you are missing both the mesio- and disto-lingual line angles• Three, because you are missing the mesial, distal, and lingual walls 96 copyright © 2016-2017 Dental DecksOPERATIVE

• Two, because you are missing both the mesio- and disto-lingual line angles*** The rule of thumb is one pin per missing line angle.The largest pin that can safely be placed should be selected in any situation. Theoptimal placement is at the line angles or corners of the tooth, where the tooth/root massis greatest and the risks of perforation into the pulp or furcation are minimal.Advantages: • More conservative and less time involved than castings • Enhances retention form (adds walls) and is an economical alternative to castingsDisadvantages: • Can cause dentin crazing • Microleakage can occur at pin channel • Pins weaken amalgam alloy • Placement can result in pulpal exposure, perforation, and fracture of the toothTypes of Pins: • Cemented • Friction-lock • Self-threading

pinsThe most retentive style of pin is the self-threaded pins because they arecemented into pinholes that are smaller than the pin itself.• Both the statement and the reason are correct and related• Both the statement and the reason are correct but not related• The statement is correct, but the reason is not• The statement is not correct, but the reason is correct• Neither the statement nor the reason is correct 97 copyright © 2016-2017 Dental DecksOPERATIVE

• The statement is correct, but the reason is not*** Although the pinhole is smaller than the self-threaded pin, it is NOT cemented.Self-threaded pin systems (for example, TMS, Whaledent) use holes sized just under thescrew diameter. The elasticity (resiliency) of the dentin functions to retain the screwed pin.This system comes with a self-limiting drill of optimal 2 mm depth and self-shearing pins thatguard against overtightening. This type of pin system is the most frequently used of the threetypes of pins.The TMS (Thread-Mate System) system has four sizes of pins (regular, minim, minikin andminuta). They are available in titanium or stainless steel plated with gold.Cemented pins are serrated stainless steel pins that are cemented into pinholes that are largerthan the diameter of the pin.Self-threading Drill Size Pin Diameter 0.031”Regular 0.027” 0.024” 0.019”Minim 0.021” 0.015”Minikin 0.017”Minuta 0.0135”Friction-locked pins are tapped into pinholes that are smaller than the diameter of the pin.They are retained by the elasticity of the dentin.Note: The increased strength of the latest dentin/enamel bonding agents, coupled with therevived use of retentive slots, pot-holes, grooves, and channels, has led to a reduction in theuse of pins. Examples of dental adhesives include: AMALGAMBOND Plus, ALL-BOND2, DenTASTIC, and Easybond. These systems allow adhesion to preconditioned substratewith the added benefits of retention and sealing of the restoration and a stronger totalcohesive mass to support all remaining cuspal segments of the tooth.

pinsA patient presents with DL cusp fracture of #14 which you decide to repair witha pin-retained amalgam core. Regarding pin placement, you are likely to do allof the following EXCEPT one. Which one is the EXCEPTION?• Use one pin at the DL axial line angle• Place the pin 2mm into dentin and restorative material• Place the pin at the DEJ to ensure adequate distance from the pulp• Bend the pin axially to allow for Amalgam condensation 98 copyright © 2016-2017 Dental DecksOPERATIVE

• Place the pin at the DEJ to ensure adequate distance from the pulp***Pin should be placed entirely in dentin approximately 0.5mm to 1mm.The main advantage of pins is to improve the retention of large restorations. Unfortu-nately, pin retention techniques are not without disadvantages. Pins are known toweaken the restorative material into which they intrude. If placed by force, they cancreate stresses that cause crazing of the tooth structure. They may provide an additionaldeep path for microleakage. If placed in close proximity to the pulp, they may aggravatean existing pulp problem or create one. The use of pins may be contraindicated in youngteeth with very large pulps and in teeth with reversible pulp pathology, which might beaggravated by instrumentation. Placement is always influenced by the limitations ofaccess and vision.Pins are not to be bent to make them parallel or to increase their retentiveness. Occasionally, bend-ing a pin may be necessary to allow for condensation of amalgam occlusogingivally. When pinsrequire bending, a bending tool must be used. A hand instrument (e.g., an amalgam condenser orspoon excavator) should not be used. Note: There should be at least 0.5 to 1.0 mm of dentin between the pin and the DEJ.Remember: Cusps to be restored with dental amalgam should be reduced by 2 mm whileforming a flat surface (perpendicular to the occlusal forces).Note: After restoring a tooth, make sure you check the occlusion very carefully. If arestoration is left in supraocclusion, the patient will return complaining of discomfortwhen biting, usually with no other symptoms.

pinsWhen preparing a pin channel, you perforate into the vital pulp chamber.What best describes your next step.• Explain to the patient the need for root canal treatment• Allow bleeding to stop, dry with paper point, place calcium hydroxide• Allow bleeding to stop, dry with paper point, place pin to depth of 1 mm as to not enter the pulp chamber• Allow bleeding to stop, dry with paper point, place pin elsewhere, and restore with amalgam 99 copyright © 2016-2017 Dental DecksOPERATIVE

• Allow bleeding to stop, dry with paper point, place calcium hydroxideRemember: If, when attempting to drill a pinhole the drill enters a vital pulp chamber,the proper treatment is to allow the bleeding to stop, dry with a sterile paper point, andplace calcium hydroxide in the hole. Proceed with a better location for a pinhole. If a pinchannel perforates the external surface of the tooth and all factors are favorable, a pin canbe placed provided there is no extension beyond the surface of the tooth.Ideally, pins should be placed 1 to 1.5 mm inside the cavosurface margin and at least 0.5mm inside the dentinoenamel junction (DEJ), if present. Placement of the pin channel atleast 0.5 mm away from the DEJ helps prevent crazing or complete fracture of theremaining enamel. Note: The optimal depth of the pinhole into the dentin is 2 mm.The rule of thumb: Pins should be 2 mm into dentin, 2 mm within amalgam, and 1 mmfrom the DEJ (to be safe) with no bends in the pins. Important: The twist drill used toprepare the pin channels must be angled so that it remains in dentin only. The channelshould be prepared parallel to the external surface of the tooth.When pins are placed nearer the occlusal surface, as in cuspal coverage areas, the pinsshould project only minimally into the restorative material (2 mm for amalgam). Long pinsnear an area of occlusal loading will significantly weaken the amalgam; additionally, thepurpose of the pin in cuspal coverage areas is to bind the cusp to the restoration and toresist lateral displacement with occlusal function.Note: Maximal inter-pin distance results in lower levels of stress in dentin.