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Endodontics
Vet Dentistry
| Questions | Answer |
|---|---|
| How many openings can be found in a typical (canine) apical delta? | 6-90 |
| What cell and tissue types compose the pulp? | odontoblasts, fibroblasts, fibrocytes, collagen fibers, elastic fibers, blood vessels, nerves |
| Where is the CEJ typically located in periodontically healthy teeth? | just inside the gingival sulcus |
| What are TOMES FIBERS? | cytoplasmic extensions from odontoblasts |
| On which portion of the root is cementum the thickest? | apical 1/3 |
| On which portion of the crown is enamel the thickest? | cusp tip |
| Which hard tissue of teeth can be repaired by the PDL? | Cementum |
| What is a BLUNDERBUSS? | An extremely wide root canal of an immature permanent tooth |
| What is a SMEAR LAYER? | smooth, amorphous layer of microcrystalline debris created by dentinal wall instrumentation |
| What is IRREVERSIBLE PULPITIS? | A pronouncement of impending partial or total pulpal death |
| What is the ANACHORECTIC EFFECT? | when bacteria reach the pulp from distant sites via the bloodstream during transient bacteremia or via regional gingival lymphatics traveling from the sulcus |
| What are the 2 forms of hyperplastic pulpitis? | Hyperplastic granulation hyperplastic swelling pulpitis |
| What causes hyperplastic pulpitis? | result of local immune system's effort to maintain the pulp's vitality |
| What factors determine whether periapical pathology will manifest acutely or chronically? | severity of trauma pathogenicity of infective organism(s) degree of infective organism challenge host resistance |
| What are 5 ways in which periapical dz exhibits itself? | 1: acute apical periodontitis 2: acute apical abscess 3: chronic apical periodontitis 4: phoenix abscess 5: chronic periapical osteitis |
| What radiographic signs of acute apical periodontitis are noted? | generally normal may see slight widening in periapical PDL space |
| What is an acute apical abscess? | painful purulent exudate of sudden onset at the apex |
| What are radiographic signs of an acute apical abscess? | Rads are usually normal |
| What is chronic apical periodontitis? | long-term inflammation around the apex, can establish itself as periapical granuloma or cyst |
| What is the radiogrpahic appearance of chronic apical periodontitis? | periapical lucency |
| What is a PHEONIX ABSCESS? | acute exacerbation of chronic apical periodontitis |
| What is the radiographic appearance of a phoenix abscess? | periapical lucency, may be assiciated with apical root loss |
| What is chronic periapical osteitis? | the osseous response observed with some low-grade chronic pulpal and periapical inflammation |
| What are the 3 common radiographic manifestations of chronic periapical osteitis? | osteosclerosis osteomyelitis (osteopenia) ankylosis |
| What are 3 possible routes for communication between the periodontal and endodontic tissues? | dentinal tubules accesory/lateral canals apical delta openings |
| What are the 4 classes of endodontic lesions with respect to periodontal involvement? | Class O: primary endo Class I: primary endo, secondary perio Class II: primary perio, secondary endo Class III: true combined lesion |
| What class of endo lesion may have a J-shaped lucency extending up the root margin from an apical halo? | Class I |
| What is the prognosis for a Class O lesion? | very good, excellent |
| What is the prognosis for a Class I lesion? | good, very good |
| What is the prognosis for Class II and III lesions? | fair to poor |
| What is another term for transillumination? | diascopy |
| What is indicated when cold temporarily relieves pain? | irreversible pulpitis |
| How does a tooth with pulpitis react to heat differently than other teeth? | more prolonged response acute pulpitis-->respond severely, can be calmed quickly with cold |
| How valuable is thermal testing for pulp status in animals? | Minimal |
| What is the most important diagnostic, prognostic, and therapeutic evaluation tool in endodontics? | radiology |
| What constitutes the ENDODONTIC TRIAD? | canal preparation sterilization obturation |
| In what ascending order are files colored, starting at what number? | white 15 yellow 20 red 25 blue 30 green 35 black 40 |
| At what size do files start increasing size in increments of 10 rather than 5? | 60 |
| What does the standard size of a file correlate with? | The diameter of instrumen immediately behind the tip at the initiation of the flutes in tenths of a milimeter (size 15=0.15 mm) |
| How long is the operative head in standardized instruments? | 16 mm |
| What is the D16 of a size 10 file? | 0.42 mm |
| What is the increase D16 size with each larger file size? | proportional increase from file 15 to 20 increases diameter at tip by 0.05 mm and by the same amount at D16 |
| What are the new specifications adhered to for endo instruments? | Standard specifications |
| What are the old specifications that used to exist for endo instruments | conventional specifications |
| What endo instruments are included in Group I? | hand instruments: K reamers, K files, H files, R rasps, barbed broaches, probes, applicators, pluggers, spreaders, pathfinders |
| What endo instruments are included in Group II? | engine driven with a 2 part shaft and operative head: lentulas and any of the instruments in group I modified for use with a handpiece |
| What endo instruments are included in Group III? | engine driven with a 1 part shaft and operative head: root facers, G-reamers (gates-glidden) and P-reamer (peeso) |
| What endo instruments are included in Group IV? | all types of points and cones: paper and GP |
| What determines whether a blank becomes a file or reamer? | The number of twists introduced to the instrument |
| How many spirals per mm and cutting flutes per mm do reamers have? | 0.1 to <0.25 spirals per mm 0.28 to 0.8 flutes per mm |
| How many spirals per mm and cutting flutes per mm do files have? | 0.25 to < 0.5 spirals per mm 0.88 to 1.97 cutting flutes per mm |
| What is the resultant difference in function between reamers and files? | Reamers have better cutting efficiency but poorer carrying ability than files |
| How are reamers used in the canal? | clockwise turning fashion |
| How are files used in the canal? | push-pull OR 1/4 turn and pull |
| How does the shape of an instrument shaft affect the cutting circle in the canal? | Triangular shaft: 1/3 rotation Square shaft: 1/4 rotation Rhomboid shaft: 1/2 rotation |
| Which is stronger, a triangular shaft or a square one? | square |
| Which is more flexible, a triangular shaft or a square one? | Triangle |
| Which is more flexible, but not as strong when comparing K files and K reamers? | reamer |
| Which is the stiffer and stronger type of file and reamer? | K |
| How is a Hedstrom or H-file produced? | A round blank is machined to produce a spiral groove on a tapered, pointed instrument |
| How should H-files be used? | push-pull |
| How far from the instrument tip is D16 measured in 60 mm files? | 30 mm |
| What is the taper per mm of operating head in standard files? | 0.02 mm |
| What is the shaft diameter at the end of the operating head of a standard file? | 0.32 mm plus the instrument size (size 15 file is 0.15 + 0.32 = 0.47 mm diameter shaft) |
| What type of surface is produced by K-files in the canal? | clean and smooth |
| What type of surface is produced by H-files in the canal? | clean but not as smooth |
| Which type of file is best for use in the apical canal? | K files, rotary motion produces a fairly round apical prep |
| What is the best place for using H files? | shaping of the occlusal flare |
| What direction should K files be turned for rotary action? | clockwise |
| What is gutta percha? | An exudate of mazer trees |
| What are Type I GP points? | standard: correspond to the sizes of standard endo instruments. Used as master points |
| What are type II GP points? | conventional: similar taper as endo spreaders. used as accessory points |
| What is the composition of most Gutta percha points? | 15-22% GP 56-79% zinc oxide remainder is combo of heavy metal sulfates, waxes, resins |
| What are 3 common solvents for GP? | CHLOROFORM EUCALYPTOL XYLOL |
| What are differences between the alpha and beta forms of GP? | thermal flow volume handling differences |
| Which form of GP is softer? | beta |
| What is the law of diffusion? | when 2 or more liquieds capable of being mixed are placed together, a spontaneous exchange of molecules takes place in defiance of the Law of Gravity |
| How does ultrasonic stimulation enhance canal cleaning? | It heats the irrigation solutions and causes a resonant vibration effect |
| What is the resonant vibration effect of ultrasonic canal cleaning called? | acoustic streaming (not a cavitation phenomenon) |
| What is the disadvantage of ultrasonic canal cleaning? | Poor canal shaping ability |
| What is the theorized mode of action of Electronic root canal measuring devices? | Electrical resistance difference between 2 probes. The difference decreases when the probe in the canal approaches the apex and soft tissue of the periapical PDL |
| What are limitation of ERCMs? | cannot give accurate reading in the presence of conductive tisues or fluids (k.e. pulp tisue, pus, irrigation fluids in the canal distort readings |
| How can errors in ERCMs be decreased? | by calculating the impedance ration between the two probe frequencies |
| How is canal depth measured radiographically? | With a file inserted to the radiographic and digital resistance of the apex, an x-ray is exposed. It is calibrated and a calculation is employed |
| What is the calculation to determine the actual length of the tooth? | TA= (IA X TR)/IR TA: length of tooth IA: actual length of the instrument TR: length of measured radiograph IR: length of instrument measured on radiograph |
| What is the endodontic triad? | Preparation Sterilization Obturation |
| What is the primary goal in preparation? | To shape the canal to create a shape that can be completely filled |
| What is the main goal for accessing a pulp cavity? | to establish an urestricted pathway for preparation of the apical canal |
| What is the access triad? | the sequence of achieving unrestricted access to each in order: the chamber, root canal, and stricture |
| What is a cornerstone of dentistry that should be considered during access for endo tx? | conservation of tooth structure |
| What is one of the most common complicating factors for veterinarians in root canal therapy? | failure to establish proper access to the pulp chamber and rot canals |
| Where should one avoid making access openings to avoid subsequent vertical fractures? | Over or through incisal edges, cusp tips, or other developmental ridges or margins |
| Where is access made relative to the gingival margin on incisors and canines? | 1-2 mm coronal to margin |
| Where is access made relative to the gingival margin for transcoronal approach to the mesial roots of the upper fourth premolar? | 2-4 mm coronal to margin, buccal tooth face |
| Which face is the access made to approach the mesial root of the mandibular first molar? | lingual |
| What canal morphology should be checked for in maxillary molars? | Ribbon canal associated with fused distal roots |
| What trick should be used if locating/accessing a highly calcified pulp cavity is proving difficult? | Go for the horns (of the pulp chamber) |
| What are 2 basic styles of root canal instrumentation? | standard/rigid core technique tapered/flared/serial/telescoping/or funneling technique which can involve either a step back or step down procedure |
| What should be done once a file lightly binds at the working tip? | instrument the canal to at least 3 sizes larger |
| What is the proper procedure to flare the coronal canal after the apical canal has been instrumented? | Size 3 Gates glidden drill used up to 5 mm short of the apex, followed by size 4 G reamer to within 6 mm of apex and so on |
| What procedure is performed after the coronal canal is flared with G reamers? | Recapitulation of the apex starting with file 25, and instrumenting 1 mm shorter with each increase in file size. Recapitulate with file 25 to full working length between each file |
| What is down stepping? | The opposite of step back instrumentation. |
| What is a possible benefit of step down instrumentation? | less packing of shavings/debris through the apex |
| How do irrigants achieve sterilization where instruments cannot reach? | the law of diffusion and chemomechanical action |
| What is thermomechanical compaction? | GP is compacted by a rotary instrument that generates frictional heat while forcing softened GP laterally and apically |
| What is the thermomechanical compactor instrument called? | Thermal Lateral compactor |
| What is the thermoplastic method of canal obturation? | thermal heating of GP to soften it to improve quality of the fill |
| What happens to GP as it cools? | Shrinks slightly |
| What is the chemoplastic method of canal obturation? | a chemical (solvent) is added to the core material (GP) to soften or dissolve it prior to placement in the canal |
| What is the disadvantage of chemoplastic obturation? | excessive shrinkage of sole-filler method borderline excessive shrinkage with dip technique |
| What is the danger of chloroform? | carcinogenic |
| How long should GP be dipped in chloroform to soften it for placement without causing excessive shrinkage? | 4-6 seconds |
| What can you dip a GP cone in to harden it after it has been molded to fit the apex? | isopropyl Alcohol |
| What is the modified chloropercha technique? | Instead of just dipping the GP cone in chloroform, it is dipped in a solution of GP dissolved in chloroform (chloropercha) |
| What is a common complication of chloropercha technique? | overfill |
| What is the disadvantage of using Eucalyptol instead of chloroform for chemoplastic obturation? | Longer duration needed to soften the GP |
| How can the limitation of eucalyptol be overcome? | heat it for 20-30 seconds in a glass dappen dish |
| How long should a GP point be soaked in warmed eucalyptol to soften it sufficientyl? | 30-45 seconds |
| What are common complications often encountered with paste obturation techniques? | over/underextension, over/underfilling, lack of positive pressure for maintenance of apical seal |
| What is the problem with underextension? | voids allow for percolation of fluids and incomplete seal between periapical tissues and the canal |
| What is the problem with overextension? | certain sealers produce varying intensity of toxicity, inflammation, or discomfort when contacting the periapical tissues |
| To what canal dimension do the terms underextension and overextension refer regarding obturation complications? | vertical fill dimension |
| What do under and over fill refer to? | obturation in any dimension |
| What method is used to sterilize GP points? | Soak them in full strength sodium hypochlorite for 1 minute (rinse and dry before placing in canal) |
| What are the radiographic signs seen to indicate successful healing after endo tx? | dissipation periapical radiolucency |
| How do periapical tissues heal after endo tx? | inflammatory cell infiltrate and excessive vascularity diminish while fibroblasts proliferate. Osteoblasts then secrete spicules of osteoid which replaces the fibrous aggregate and undergoes mineralization |
| Why does it take 4-12 months before rads can confirm complete healing of a periapical lesion? | because osteoid is not radiopaque and newly mineralized trabecular bone contains insufficient calcium salts to be evident radiographically |
| What are 2 possible causes of failed healing post endo tx? | Incomplete therapy or persistent periapical cyst |
| What tooth characteristic influence regeneration of pulp-like tissue in the pulp chamber after tooth transplantation, replantation, or in regenerative endo tx? J Endod 2013 | diameter of apical foramen (must be open, but minimal width is undetermined) |
| What biologic fluid causes the most corrosion of endodontic files? (compared to other biologic fluids) Scanning 2012 | blood |
| What non-biologic fluid causes the most corrosion of endodontic files? Scanning 2012 | sodium hypochlorite NaOCl (which causes more corrosion than blood) |
| What was the conclusion of the study designed to evaluate the effect of MTA-based sealer on periapical tissue healing? J Appl Oral Sci 21(3) | endodontic treatment performed in a single session using these materials cannot support complete healing of the periapical tissues of canine teeth. |
| How might one avoid the major difficulty of retrograde MTA placement in the apical canal after apicoectomy? Eur J Dent 2011 | place MTA at the apex orthograde prior to apicoectomy to the level of the set MTA (study results showed it to be statistically 'acceptable' but freshly placed MTA seemed to perform better) |
| How does Copaifera langsdorffii oil-resin perform when used as pulp capping agent? Pediatr Dent 2011 | less severe inflam response, smaller area of pulp necrosis, more frequent formation of mineralized tissue barrier (compared to 3 other materials tested) |
| Does Nd:YAG laser irratiation at power outputs of 1-4 W damage pulp tissue (when studied in rabbit teeth)? Photomed Laser Surg 2010 | no damage to pulp tissue was observed |
| How does calcium hydroxide affect the presence of bacterial endotoxin (LPS) in a root canal? 2008 Braz Dent J | CaOH effectively inactivates LPS |
| What is the apexum procedure? 2009 J endod | Apexum procedure uses 2 sequential rotary devices designed to extend beyond the apex and to mince periapical tissues on rotation in a low-speed handpiece, followed by washing out the minced tissue |
| Is there some benefit seen with the apexum procedure? 2009 J endod | significantly enhance healing kinetics of apical periodontitis compared with conventional nonsurgical endodontic treatment |
| What instruments for pulp space preparation are in group 1? pathways of the pulp p. 238 | hand and finger operated instruments (barbed broaches, K and H files) |
| What instruments for pulp space preparation are in group 2? pathways of the pulp p. 238 | low speed instruments on which the latch type of attachment is part of the working section (gates glidden burs, peeso reamers) |
| What instruments for pulp space preparation are in group 3? pathways of the pulp p. 238 | engine driven instruments similar to hand and finger operated instruments, but the handles have been replaced with attachments for a latch type of handpiece. (i.e. lightspeed) |
| What is the difference between a K file and a K reamer? pathways of the pulp p. 239 | file has more flutes per length unit |
| When plasticized by heat, what is the shrinkage volume loss of GP when it cools? pathways of the pulp p.275 | 2% |
| How common are non apical ramifications of the root canal in maxillary carnassial teeth in dogs? JVD spring 2001 | 68% (they are most common in the distal root) (approx 2 out of 3 teeth) |
| How common are non apical ramifications of the root canal in mandibular first molar teeth in dogs? JVD spring 2001 | 20% (approx 1 out of 5 teeth) |
| How many non apical ramifications have been reported in incisors and canine teeth of dogs? | 3% |
| How much apical resection is recommended for sx endo? JVD spring 2001 | 4-6 mm |
| Which teeth might be better treated with resection of the upper recommended limit in surgical endo? why? JVD spring 2001 | mandibular M1, b/c ~20% of them have apical delta > 3mm thick |
| In regards to combined lesions, what is a class 0 endo lesion? JVD spring 2001 | endo only |
| In regards to combined lesions, what is a class 1 endo lesion? JVD spring 2001 | primary endo, secondary perio |
| In regards to combined lesions, what is a class 2 endo lesion? JVD spring 2001 | primary perio, secondary endo |
| In regards to combined lesions, what is a class 3 endo lesion? JVD spring 2001 | true mixed |
| How should GP points be sterilized prior to use for obturation? PoP pg 263 | soak in 5% NaOCl for 1 minute. Very important to rinse (in ethyl alcohol) prior to use b/c crystalilized NaOCl impair obturation seal |
| How can one manage the amount of shrinkage that occurs after thermoplasticized GP cools? PoP p 263 | controlled heating temps (open flame less optimal than controlled devices, i.e. touch 'n heat) |
| At what temp do GP cones soften? PoP p 263 | 147 degrees F (transition from Beta to alpha phase at 115 degrees F) |
| What type of adhesive properties does chloropercha have as a RC sealer? PoP p 266 | no adhesive qualities |
| What happens to CaOH to render it therapeutically effective as an antimicrobial? PoP p 268 | must dissociate into Ca++ and OH- (in water) |
| Which component of AH 26 RC sealer has tissue toxicity? How was this addressed? PoP p 269 | a small amount of formaldehyde is released as a result of the chemical setting process. New product AH Plus does not release formaldehyde |
| What component of ZOE RC sealer has tissue toxicity? PoP p 265 | Eugenol. |
| What happens to the ZOE apical seal over time? What can be added to reduce this change? PoP p266 | ZOE cements lose some volume with time b/c of dissolution in tissues withthe release of eugenol (cytotoxic) and zinc oxide (antimicrobial). Adding resin acids reduces dissolution |
| What kind of tissue do lower concentrations of NaOCl dissolve? PoP p 319 | necrotic |
| What kind of tissue does higher concentration of NaOCl dissolve? PoP p 319 | necrotic & vital |
| How far past the end of the needle to irrigants penetrate when flushing a root canal? PoP p 324 | 1 mm |
| What is considered the minimum critical radicular dentin thickness to maintain structural integrity/prevent fx? PoP p324 | 0.2 mm |
| What does contact with dentin and dentin power/chips do to the efficacy of many disinfectants? PoP p 343 | inactivates them |
| What effect do EDTA and NaOCl have on eachother? PoP p 343 | they inactivate eachother |
| How does NaOCl work against bacteria? How must it therefore be used to optimize this effect? PoP p 344 | free Chlorine. Must continually be frequently replenished to continually supply the Cl- |
| what is the desired level of obturation? PoP p377 | CEJ |
| What is a disadvantage of softening GP in solvents? PoP p389 | shrinkage as the solvents dry off |
| What is the difference between pulpotomy and pulpectomy? PoP p620 | pulpotomy removes pulp from the crown; pulpectomy removes the entire pulp down to the apical foramen |
| What is the incidence of pulp necrosis when there is root fracture? PoP p629 | ~25% (usually necroses in the coronal segment) |
| What power setting should be used for ultrasonic root end prep during sx endo? PoP p 755 | low setting |
| Which type of periapical cyst 'should' heal after normograde RC therapy? PoP p 927 | a periapical POCKET cyst |
| What are the 5 biologic factors that can cause persistent periapical radiolucency after RC tx? PoP p 934 | persistent bacteria in root canal; extra-radicular infxn (periapical actinomycosis); extruded root canal filling or other materials (FB rxn); true cystic lesions (esp. w/cholesterol crystals); scar tissue healing of the lesion (vs bone) |
| What is the APEXUM procedure? J Endod 2009 | removal of the inflamed periapical tissues through root canal access: 2 sequential rotary devices designed to extend beyond the apex to mince periapical tissues on rotation in a low-speed handpiece, minced tissues are then rinsed out |
| What is the proposed purpose of the Apexum procedure? J Endod 2009 | to enhance healing kinetics of periapical lesions |
| What the benefit of Apexum procedure 'proven'? J Endod 2009 | yes, radiographically and clinically (but no histo performed) |
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lamarron
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