Top 100-50 COPY

Question 1

Kakehashi, 1965, OOO

Answer 1

The effects of surgical exposures of dental pulps in germ-free and conventional rats. 21 germ free rats healed after pulpal exposure, no apical pathosis found. 15 conventional developed pulpal necrosis. Presence of absence of microbial flora is the major determinant in the healing of exposed pulps.

Question 2

Zack and Cohen, 1965, OOO

Answer 2

Pulp response to eternally applied heat. Monkeys. Heat was applied to teeth with soldering iron for periods of 5 to 20 seconds. Increase in internal temperature: 4 F; minimal pulpal changes at time of experiment, no distinguishable changes from normal teeth afterwards. 10 F; destruction and aspiration of odontoblasts into tubules, destruction of Tome’s fibrils. Recovery after 56 days but with scaring (irritation dentin). 20 F; complete disruption and destruction of odontoblast in the area. some developed pulpal abscess, others necrosis. Some developed dentoalveolar abscess 30 F; all teeth irreversible necrotic response. some severe dentoalveolar abscesses. Quantity and intensity of heat applied to pulp are important. Use coolant when drilling.

Question 3

Sjogren, 1990, JOE

Answer 3

Factors affecting the long-term results of endo treatment. 356 pt’s 8-10 yrs after tx. Success rates: Vital/non-vital pulp w/o PARL; > 96% Necrotic with PARL= 86% Retreat with PARL= 62% Factors: Instrumentation to full length; 90% healing rate of PARL short; 69% healing rate of PARL Level of obturation; W/i 2mm of apex= 94% normal PA conditions overextended= 76% short = 68%

Question 4

Sundqvist, 1998, OOO

Answer 4

Microbiological analysis of teeth with failed endo treatment and the outcome of conservative retreatment. 54 RCT teeth with persistent PARL were retreated, sampled and followed for 5 yrs. Microflora; Mainly single species of mostly G+. Most commonly found; E. faecalis (really?, no sh#$) Overall success rate = 74% flora of untreated teeth is different. Infection at the time of obturation and size of PARL had as significant negative influence on the prognosis. A. israelii associated with lack of healing of PARL.

Question 5

Scheider, 1971, OOO

Answer 5

A comparison of canal preparations in straight and curved root canals. Degrees of root curvature: Straight = 5 degrees or less Moderate = 10-20 degrees Severe = 25 - 70 degrees Straight canals are much more readily prepared.

Question 6

Sjogren, 1997, IEJ

Answer 6

Influence of infection at the time of root filling on the outcome of RCT of teeth with apical periodontitis. 55 single rooted teeth with apical periodontitis, instrumented and irrigated with NaOCl. Follow 5 yrs Success rate: Negative culture at time of obturation; 94% complete pa healing. Positive culture at time of obturation; 68% healing of pa lesion. Period of 4-5 years necessary to see the full impact of the persistent bacteria on the prognosis. Obturation should be delayed until after a suitable period of medication with an antimicrobial dressing to eradicate all infection which is impossible in one visit. ie. two visits are advocated.

Question 7

Molander, 1998, IEJ

Answer 7

Microbial status of RCT with apical periodontitis. 100 RCT with PARL Predominant species; G+ Facultative anaerobic = 69% Most frequent species: E. faecalis Microflora of treated teeth varies from flora of untreated necrotic pulp quantitatively and qualitatively. Other causes of PARL: PA cyst, foreign body reaction, scar tissue. Use of CaOH between appointments to eliminate E. faecalis is probably not effective.

Question 8

Torabinejad, 1995, JOE

Answer 8

Physical and chemical properties of a new root-end filling material. Chemical composition of MTA and comparison to amalgam, super EBA and IRM. MTA: Composition; tricalcium: silicate, aluminate and oxide, silicate oxide. Main molecules; Calcium and phosphorous ions (components of dental hard tissues)(biocompatible when used in contact with cells and tissues. pH; 10.2 initially, rises to 12.5 three hours after mixing.Induction of hard tissue formation might occur. Radiopacity; more than EBA and IRM Setting time; longest; 2h 45 min. Compressive strength; lowest at first, increases after 21 days to 67 MPa.

Question 9

Ray and Trope, 1995, IEJ

Answer 9

Periapical status of RCTT in relation to the technical quality of the root filling and the coronal restoration. 1010 RCTT with permanent restorations were evaluated at Temple U in terms of quality of endo and coronal restoration. Best; GE and GR (91.4% API) Better; GR (80% API) Good; GE (75.7% API) The technical quality of the coronal restoration was significantly more important that the quality of the RCT for periodontal health. Good crown matters more than good endo. yeah right! API; Absence of periapical inflammation.

Question 10

Walia, 1988, JOE

Answer 10

An initial investigation of the bending and torsional properties of NITI root canal files. NITI: Very low modulus of elasticity. Two to three times more elastic flexibility in bending and torsion and resistance to torsional fracture as compared to SS. Large elastic deformation before fracture. Superior fracture resistance is due to the ductility of NITi.

Question 11

Torabinejad, 1999, JOE

Answer 11

Clinical applications of MTA (Raise the dead) *Prevents mircroleakage *Biocompatible *Promotes regeneration of original tissues when in contact with pulp or periradicular tissues. Applications: >Vital pulp therapy: pulp capping material; stimulates dentin bridge formation due to sealing ability, biocompatability, alkalinity. >Apical barrier (plug) in teeth with immature apexes. >Repair of root perforations; MTA has significantly less leakage than IRM or amalgam. >Root-end filling material; less inflammation, cementum formation over MTA, regeneration of PA tissues. Temporizing material. Repair vertical fractures.

Question 12

Torabinejad, 1993, JOE

Answer 12

Sealing ability of a Mineral Trioxide Aggregate when used as a root end filling material. Dye penetration experiment with 30 extracted teeth to compare sealing ability of MTA, amalgam and super EBA. Result MTA leaked significantly less than amalgam or EBA.

Question 13

Bystrom and Sundqvist, 1985, IEJ

Answer 13

The antibacterial action of NaOCL and EDTA in 60 cases of endo therapy. No significant difference in the use of 0.5 or 5.0% NaOCl as an antibacterial. Use of EDTA in combination with 5% NaOCl is more efficient than NaOCl alone. Fresh NaOCl should be applied frequently as it becos inactivated.

Question 14

Nair, 1990, JOE

Answer 14

Intraradicular bacteria nd fungi in Root-filled, asymptomatic human teeth with therapy-resistant PARL. Light and E. microscope analysis of 9 therapy resistant teeth. Presence of intraradicular microorganisms (bacteria and fungi) in teeth with persistent pa lesions. Other non-healing lesions can be the involvement of a foreign body giant cell type.

Question 15

Torabinejad, 1990, JOE

Answer 15

In vitro Bacterial penetration of coronary unsealed RCTT. 45 root canals were RCT via lateral condensation. Coronal portion was filled with S. epidermis and P. vulgaris. and time for complete bacterial penetration was recorded. 50% of root canals fully contaminated in: 19 day exposure to S. epidermidis 42 day exposure to P. vulgaris This study used the apparatus invented by Dr. Torabinejad that Dr. Chogle pointed out. Flask with a tooth suspended inside by a plastic barrier on the coronal portion. apex is submerged in liquid. Bacterial contamination has happened when liquid changed colors. Motility of bacteria is not a factor in the rate of penetration.

Question 16

Vertucci, 1984, OOO

Answer 16

Root canal anatomy of the human permanent teeth.

Question 17

Sjogren, 1991, IEJ

Answer 17

The antimicrobial effect of CaOH as a short term intracranial dressing. 30 teeth with necrotic pulps, PARL. 12 cases treated with CaOH for 10 minutes. 18 cases treated with CaOH for 7 days. Teeth were sampled under anaerobic conditions. 10 minutes; treatment was ineffective, bacteria was still present at second appointment. 7 days; bacteria could not be recovered 1-5 days after removal of dressing or immediately afterwards. Facultative anaerobic isolate was E. faecalis.

Question 18

Wang and Hume, 1988 Unrelated to top 100

Answer 18

Buffering capacity of hydroxyapatite prevents the readily diffusion of CaOH ions. buffering can eventually be overcome given sufficient availability of hydroxyl ions over time.

Question 19

Pruett, 1997, JOE

Answer 19

Cyclic fatigue testing of NITI endo instruments. Factors affecting cyclic fatigue” Most to least in predicting instrument separation *Radius of curvature; as radius of curvature decreased so did amount of cycles to failure. *Angle of curvature; As angle decreases so does amount of cycles to failure. Instrument shaft diameter; As diameter increased cycles to failure decreased. Operating RPM

Question 20

Orstavik and Haapasalo, 1990,

Answer 20

Disinfection by endodontic irritants and dressings of experimentally infected dentinal tubules. Bovine dentin specimens infected with E. faecalis, S sangis, E. coli or P. aeruginosa. Specimens were infected for up to 14 days and degree of infection was monitored. E. faecalis; rapid infection of the whole length and survival after removal of nutrients. S. sanguis; 2 weeks for complete infection. E.coli; only penetrated 600µm. except for E.faecalis all other organisms died after 4 to 48 hrs. IKI more potent than NaOCl or CHI. Presence of smear layer delayed but did not eliminate the effect of the medicaments.

Question 21

Wu and Wesselink, 1993, IEJ

Answer 21

Endodontic leakage studies reconsidered More research is needed on the methodology of leakage studies. Way too many studies in the 80 and 90s with varying results that provide little relevant information.

Question 22

Roane, 1985, JOE

Answer 22

The Balanced force concept for instrumentation of curved canals. Balanced force was derived from the law; for every action there is an equal and opposite reaction. Magnitude of the restoring force is a function of: File’s mass Geometry composition Radius and arc of instrumentation curve. Placement is accomplished using CW rotation no more than 180 degrees with light inward pressure. Cutting is accomplished using CCW rotation of at least 120 degrees and inward pressure. Cleaning or debris removal is accomplished using one or two non cutting, no pressure outward pull clockwise rotation. Balance force allows you to produce enlargement of canals past severe curvatures.

Question 23

Bystrom, 1983, OOO

Answer 23

Bacteriologic evaluation of math effect for 0.5 % NaOCl in endodontic therapy. No bacteria could be recovered from 12 out of 15 root canals at the fifth appointment when NaOCl was used No bacteria could be recovered from 8 out of 15 root canals when saline was used NaOCl is more effective than saline. 88% of strains recovered were anaerobic. Most common; F. nucleatum Closed RCS seems to be a selective milieu where the composition of the flora is influenced by: Changes in anaerobiosis. nutritional interrelationships. More studies are needed to evaluate higher concentrations of NaOCl.

Question 24

Pineda and Kutler, 1972, OOO

Answer 24

Mesiodistal and buccolingual roentgenographic investigation of 7275 root canals. Apical Exit: 16.9% Lateral exit: 83% (6018 Canals) Apical foramen diameter increases with age Most canals are curved and cone shaped.

Question 25

Shipper, 2004, JOE

Answer 25

An evaluation of microbial leakage in roots filled with Resilon. compare bacterial leakage through GP and resilon using S. mutant and E. faecalis. Resilon; thermoplastic synthetic polymer of polyester. Epiphany; Dual cure dental resin composite sealer. 40 sec of light will cure the coronal 2 mm, entire fill will cure in approx 15 to 30 min. Resilon can be removed with chloroform. Resilon is very compatible since it can be used for tissue engineering but it can also be degraded by the body. Polymerization is never 100% Resin tags into dentin to form mono block.

Question 26

Lee, 1993, JOE Torabinejad was the third author

Answer 26

Sealing ability of MTA for repair of lateral root perforations Comparison of amalgam, IRM and MTA 50 extracted teeth were repaired after creating a lateral root perforation and them placed in saline for four weeks. Factors that affect prognosis of repair Contamination of perforation site Location Size Operator skill Material of choice. MTA performed better than the other two materials.

Question 27

Glosson, 1995, JOE

Answer 27

A comparison of RC preparations using NITI hand and engine driven and k-flex endo instruments. Canal curvature and shape: no significant difference with the different instruments. Canal transportation; Less with NITI rotary instruments. SS instruments are able to negotiate obstructions better because they do not bend, also better tactile sensation.

Question 28

Saunders and Saunders, 1994

Answer 28

Coronal leakage as a cause of failure in RCT. A review More important to seal the coronal part of molars with glass ionomer due to the presence of accessory canals in this area It is important to remove the smear layer because it can be broken down by bacterial toxins Crown of tooth should be restored expeditiously. Temp material should be at least 3.5 mm thick. Chemically active adhesives might play an important role in the future.

Question 29

Sundqvist, Johansson and Sjogren, 1989

Answer 29

Prevalence of Black-pigmented bacteroides species in root canal infections. Positive association between black-pigmented Bactroides species and apical abscess formation

Question 30

Tronstad, 1988,

Answer 30

Root resorption - etiology, terminology and clinical manifestations. Classifications: Inflammatory; Precementum or Predentin become mineralized, could be internal or external. Either transient or progressive and it requires an intervention to stop it. Replacement; seen it teeth that have become ankylosed and incorporated into the bone. Transient; Occurs as a result of trauma, ortho, perio tx, self limiting to 2-3 weeks. Not clinically significant. Progressive inflammatory; due to continued stimulation to resorbing cells such as mechanical, pressure, infection or systemic diseases. Internal resorption; takes place w/i RCS after loss of predentin and odontoblast layer. uncommon in permanent teeth. external resorption; can be progressive, vertical or replacement.

Question 31

Torabinejad, 1997, JOE

Answer 31

Histologic assessment of MTA as a root-end filling in monkeys. MTA had cementum deposition and PDL attachment. Amalgam did not prevent micro leakage and did not allow for regeneration of dentinoalveolar tissues.

Question 32

Torabinejad, 1995, JOE

Answer 32

Investigation of Mineral Trioxide Aggregate for Root-End Filling in Dogs. Regeneration of cementum over MTA MTA is probably capable of the activation of cementoblast.

Question 33

Spangber, 1973, OOO

Answer 33

Biologic effects of dental materials. Toxicity and antimicrobial effect of endo antiseptics in vitro Toxic effects of NaOCl, CHI, Iodopax are 10X grater than their antimicrobial effects NaOCl at 5% is highly toxic and irritating to the tissue, dissolves necrotic and vital tissue. Lower concentrations should be considered. Chlorhexidine; low toxicity but minimal cleansing effect. Iodine solutions might discolor tooth and patient might be hypersesitive.

Question 34

Swanson and Madison, 1987, JOE

Answer 34

An Evaluation of Coronal Microleakage in Endodontically Treated Teeth. Part I. Time Periods Evaluation of micro leakage when obturation material are exposed to fluids. Significant amount of micro leakage is evident after three days of exposure to saliva.

Question 35

Reset

Answer 35

Reset

Question 36

Baumgartner, 1987, JOE

Answer 36

A Scanning Electron Microscopic Evaluation of Four Root Canal Irrigation Regimens. Compare debriment capabilities of saline, 5.25% NaOCl, 15% EDTA and combinations. EDTA removes smear layer but not organic material. NaOCl removes organic debris and its antibacterial but does not remove SL. Alternating EDTA and NaOCL effectively removes smear layer, tissue, predentin and increases antimicrobial activity

Question 37

Torabinejad, 1995, JOE

Answer 37

Bacterial leakage of mineral trioxide aggregate as a root-end filling material. Compare bacterial leakage potential of amalgam, Super-EBA, IRM, and MTA. EBA, IRM and amalgam showed leakage at 6-57 days. MTA showed no leakage at 90 days.

Question 38

Koh, 1998, JOE Torabinejad was fifth author.

Answer 38

Cellular response to mineral trioxide aggregate. IRM; cytotoxic, cell death in three days when in contact. MTA; Biocompatible, cells remained healthy when in contact. Increases presence of presence of cytokines: IL1a, IL1b and IL6. promotes cytokine release from osteoblasts.

Question 39

Schwartz, 2004, JOE

Answer 39

Post Placement and Restoration of Endodontically Treated Teeth. Retrievability easiness; metal\>fiber\>ceramic/zirconium basically impossible Post length should be equal to ¾ length of the root or at least the length of the crown but no less than 8mm or longer than 4 to 5 mm from apex to maintain adequate seal. A 1 mm of vertical height ferrule doubles the resistance to fracture. Maximum benefit achieved with 1.5 to 2 mm ferrule

Question 40

Sundqvist, 1994,OOO

Answer 40

Taxonomy, ecology and pathogenicity of the root canal flora. The bacterial synergy is an important factor in determining the pathogenicity of the polymicrobial root canal floral Most common bacteria; Peptostreptococci (micros and anaerobicus ) · Gram pos, anaerobic, non spore forming. Most frequently isolated species from intact canals; Fusobacterium nucleatum Most common in treatment failure; A. israelii due to its ability to establish infections in the periapical tissues.

Question 41

Sundqvist, 1992, JOE

Answer 41

Ecology of the root canal flora. The factors may influence the ecology of the root canal bacteria composition 1. Number of bacteria species is in proportion to the apical lesion size. 2. The root canal environment is dynamic and selective. (e.g. the relative proportion of anaerobic bacterial strains increased with time) 3. Bacterial interrelationships: both positive and negative influences (e.g. F. nucleatum is positively related to P. micros, W. recta, P. endodontalis, and S. sputigena) (e.g. A. israelii is positively related to P. propionicus,) 4. Nutrition supply: different phase of infection provides different kind of nutrition to bacteria First: Glucose/F. Nucleatum Second: Glycoproteins/B. Intermedius Third: Amino acid and peptide/P. Micros 5. Bacteriocins: Some species produce bacteriocins (protein) and inhibit other species (e.g. P. endodontalis inhibits the growth of B. intermedius) 6. Endodontic treatment

Question 42

Torabinejad, 1994, JOE

Answer 42

Dye Leakage of Four Root End Filling Materials: Effects of Blood Contamination. MTA leaked significantly less than other tested materials as an retro-filling material, and the result was not affected by blood contamination

Question 43

Reset

Answer 43

Reset

Question 44

Ciucchi, 1995, JOE

Answer 44

Dentinal Fluid Dynamics in Human Teeth, In Vivo 5 first and second mandibular bicuspids in children 12-15. Class V preparation. Hydraulic apparatus to evaluate pulpal pressure in vivo All five teeth exhibited an outwardly directed fluid flow when exogenous pressure was set at 0. Mean value of the spontaneous fluid flow was 0.36µl min-1 cm-2 .

Question 45

Ree, 1989, JOE

Answer 45

Reduction in Tooth Stiffness as a Result of Endodontic and Restorative Procedures.

Question 46

Peters, 2004, JOE

Answer 46

Current Challenges and Concepts in the Preparation of Root Canal Systems: A Review Main issues • Identification, accessing, and enlargement of the main canals without procedural errors • Establishing and maintaining adequate working lengths through- out the shaping procedure • Selection of preparation sizes and overall geometries that allow adequate disinfection and subsequent obturation. Results. NiTi instruments clinically showed a low incidence of preparation errors, satisfactory obturation as judged from radiographs, and significantly improved healing com- pared with a control group treated with stainless-steel instruments

Question 47

Sattapan, 2000, JOE

Answer 47

Defects in Rotary Nickel-Titanium Files After Clinical Use 378 used files analyzed, used by one endodontist. 50% showed some defect 21% were fractured, of those Torsional fracture = 56% perhaps due to too much apical pressure during instrumentation. Flexural fatigue = 44% usually in larger instruments, just like Pruett study Conclusion; Use light apical pressure. Do not keep instrument rotating in the same position for an extended period of time. Examine each instrument before use.

Question 48

Torabinejad, 1995, JOE

Answer 48

Cytotoxicity of four root end filling materials. Compared; Amalgam, EBA, IRM and MTA Amalgam was less cytotoxic fresh and set followed by MTA. 24 hrs later from less to most cytotoxic: Amalgam, MTA, EBA, IRM

Question 49

Ford, 1995, OOO Torabinejad is second author

Answer 49

Use of MTA for the repair of furcal perforations. 30 furcal perfs on 7 beagle dogs. As per Ingle, perforations are the second greatest cause of failure; 10%. Perf of apical and middle third have a better prognosis. Favorable response to MTA if filled immediately, including cementum formation over MTA and PDL attachment. Poor prognosis due to infection if repair is delayed, epitheleal proliferation was seen in this group.

Question 50

Standlee and Caputo, 1972

Answer 50

Analysis of stress distribution by endodontic posts threaded posts generate a high level of stress but best stress distribution at short lengths. Tappered posts exhibit a wedging effect. Parallel posts generate the highest apical stress.

Question 51

Goldman, 1972, Tufs

Answer 51

Endodontic success, Who is reading the radiograph. 6 examiners, 253 cases. Agreement was reached in less than half the cases.

Question 52

Nair, 2005

Answer 52

Microbial status of apical root canal system of human mandibular first molars with primary apical periodontitis after “one-visit” endodontic treatment. anatomical complexity of the RCS and organization of microflora under biofilm prevent the complete removal by instrumentation and irrigants in a single visit.

Question 53

The effects of surgical exposures of dental pulps in germ-free and conventional rats. 21 germ free rats healed after pulpal exposure, no apical pathosis found. 15 conventional developed pulpal necrosis. Presence of absence of microbial flora is the major determinant in the healing of exposed pulps.

Answer 53

Kakehashi, 1965, OOO

Question 54

Pulp response to eternally applied heat. Monkeys. Heat was applied to teeth with soldering iron for periods of 5 to 20 seconds. Increase in internal temperature: 4 F; minimal pulpal changes at time of experiment, no distinguishable changes from normal teeth afterwards. 10 F; destruction and aspiration of odontoblasts into tubules, destruction of Tome's fibrils. Recovery after 56 days but with scaring (irritation dentin). 20 F; complete disruption and destruction of odontoblast in the area. some developed pulpal abscess, others necrosis. Some developed dentoalveolar abscess 30 F; all teeth irreversible necrotic response. some severe dentoalveolar abscesses. Quantity and intensity of heat applied to pulp are important. Use coolant when drilling.

Answer 54

Zack and Cohen, 1965, OOO

Question 55

Factors affecting the long-term results of endo treatment. 356 pt's 8-10 yrs after tx. Success rates: Vital/non-vital pulp w/o PARL; \> 96% Necrotic with PARL= 86% Retreat with PARL= 62% Factors: Instrumentation to full length; 90% healing rate of PARL short; 69% healing rate of PARL Level of obturation; W/i 2mm of apex= 94% normal PA conditions overextended= 76% short = 68%

Answer 55

Sjogren, 1990, JOE

Question 56

Microbiological analysis of teeth with failed endo treatment and the outcome of conservative retreatment. 54 RCT teeth with persistent PARL were retreated, sampled and followed for 5 yrs. Microflora; Mainly single species of mostly G+. Most commonly found; E. faecalis (really?, no sh#$) Overall success rate = 74% flora of untreated teeth is different. Infection at the time of obturation and size of PARL had as significant negative influence on the prognosis. A. israelii associated with lack of healing of PARL.

Answer 56

Sundqvist, 1998, OOO

Question 57

A comparison of canal preparations in straight and curved root canals. Degrees of root curvature: Straight = 5 degrees or less Moderate = 10-20 degrees Severe = 25 - 70 degrees Straight canals are much more readily prepared.

Answer 57

Scheider, 1971, OOO

Question 58

Influence of infection at the time of root filling on the outcome of RCT of teeth with apical periodontitis. 55 single rooted teeth with apical periodontitis, instrumented and irrigated with NaOCl. Follow 5 yrs Success rate: Negative culture at time of obturation; 94% complete pa healing. Positive culture at time of obturation; 68% healing of pa lesion. Period of 4-5 years necessary to see the full impact of the persistent bacteria on the prognosis. Obturation should be delayed until after a suitable period of medication with an antimicrobial dressing to eradicate all infection which is impossible in one visit. ie. two visits are advocated.

Answer 58

Sjogren, 1997, IEJ

Question 59

Microbial status of RCT with apical periodontitis. 100 RCT with PARL Predominant species; G+ Facultative anaerobic = 69% Most frequent species: E. faecalis Microflora of treated teeth varies from flora of untreated necrotic pulp quantitatively and qualitatively. Other causes of PARL: PA cyst, foreign body reaction, scar tissue. Use of CaOH between appointments to eliminate E. faecalis is probably not effective.

Answer 59

Molander, 1998, IEJ

Question 60

Physical and chemical properties of a new root-end filling material. Chemical composition of MTA and comparison to amalgam, super EBA and IRM. MTA: Composition; tricalcium: silicate, aluminate and oxide, silicate oxide. Main molecules; Calcium and phosphorous ions (components of dental hard tissues)(biocompatible when used in contact with cells and tissues. pH; 10.2 initially, rises to 12.5 three hours after mixing.Induction of hard tissue formation might occur. Radiopacity; more than EBA and IRM Setting time; longest; 2h 45 min. Compressive strength; lowest at first, increases after 21 days to 67 MPa.

Answer 60

Torabinejad, 1995, JOE

Question 61

Periapical status of RCTT in relation to the technical quality of the root filling and the coronal restoration. 1010 RCTT with permanent restorations were evaluated at Temple U in terms of quality of endo and coronal restoration. Best; GE and GR (91.4% API) Better; GR (80% API) Good; GE (75.7% API) The technical quality of the coronal restoration was significantly more important that the quality of the RCT for periodontal health. Good crown matters more than good endo. yeah right! API; Absence of periapical inflammation.

Answer 61

Ray and Trope, 1995, IEJ

Question 62

An initial investigation of the bending and torsional properties of NITI root canal files. NITI: Very low modulus of elasticity. Two to three times more elastic flexibility in bending and torsion and resistance to torsional fracture as compared to SS. Large elastic deformation before fracture. Superior fracture resistance is due to the ductility of NITi.

Answer 62

Walia, 1988, JOE

Question 63

Clinical applications of MTA (Raise the dead) \*Prevents mircroleakage \*Biocompatible \*Promotes regeneration of original tissues when in contact with pulp or periradicular tissues. Applications: \>Vital pulp therapy: pulp capping material; stimulates dentin bridge formation due to sealing ability, biocompatability, alkalinity. \>Apical barrier (plug) in teeth with immature apexes. \>Repair of root perforations; MTA has significantly less leakage than IRM or amalgam. \>Root-end filling material; less inflammation, cementum formation over MTA, regeneration of PA tissues. Temporizing material. Repair vertical fractures.

Answer 63

Torabinejad, 1999, JOE

Question 64

Sealing ability of a Mineral Trioxide Aggregate when used as a root end filling material. Dye penetration experiment with 30 extracted teeth to compare sealing ability of MTA, amalgam and super EBA. Result MTA leaked significantly less than amalgam or EBA.

Answer 64

Torabinejad, 1993, JOE

Question 65

The antibacterial action of NaOCL and EDTA in 60 cases of endo therapy. No significant difference in the use of 0.5 or 5.0% NaOCl as an antibacterial. Use of EDTA in combination with 5% NaOCl is more efficient than NaOCl alone. Fresh NaOCl should be applied frequently as it becos inactivated.

Answer 65

Bystrom and Sundqvist, 1985, IEJ

Question 66

Intraradicular bacteria nd fungi in Root-filled, asymptomatic human teeth with therapy-resistant PARL. Light and E. microscope analysis of 9 therapy resistant teeth. Presence of intraradicular microorganisms (bacteria and fungi) in teeth with persistent pa lesions. Other non-healing lesions can be the involvement of a foreign body giant cell type.

Answer 66

Nair, 1990, JOE

Question 67

In vitro Bacterial penetration of coronary unsealed RCTT. 45 root canals were RCT via lateral condensation. Coronal portion was filled with S. epidermis and P. vulgaris. and time for complete bacterial penetration was recorded. 50% of root canals fully contaminated in: 19 day exposure to S. epidermidis 42 day exposure to P. vulgaris This study used the apparatus invented by Dr. Torabinejad that Dr. Chogle pointed out. Flask with a tooth suspended inside by a plastic barrier on the coronal portion. apex is submerged in liquid. Bacterial contamination has happened when liquid changed colors. Motility of bacteria is not a factor in the rate of penetration.

Answer 67

Torabinejad, 1990, JOE

Question 68

Root canal anatomy of the human permanent teeth.

Answer 68

Vertucci, 1984, OOO

Question 69

The antimicrobial effect of CaOH as a short term intracranial dressing. 30 teeth with necrotic pulps, PARL. 12 cases treated with CaOH for 10 minutes. 18 cases treated with CaOH for 7 days. Teeth were sampled under anaerobic conditions. 10 minutes; treatment was ineffective, bacteria was still present at second appointment. 7 days; bacteria could not be recovered 1-5 days after removal of dressing or immediately afterwards. Facultative anaerobic isolate was E. faecalis.

Answer 69

Sjogren, 1991, IEJ

Question 70

Buffering capacity of hydroxyapatite prevents the readily diffusion of CaOH ions. buffering can eventually be overcome given sufficient availability of hydroxyl ions over time.

Answer 70

Wang and Hume, 1988 Unrelated to top 100

Question 71

Cyclic fatigue testing of NITI endo instruments. Factors affecting cyclic fatigue" Most to least in predicting instrument separation \*Radius of curvature; as radius of curvature decreased so did amount of cycles to failure. \*Angle of curvature; As angle decreases so does amount of cycles to failure. Instrument shaft diameter; As diameter increased cycles to failure decreased. Operating RPM

Answer 71

Pruett, 1997, JOE

Question 72

Disinfection by endodontic irritants and dressings of experimentally infected dentinal tubules. Bovine dentin specimens infected with E. faecalis, S sangis, E. coli or P. aeruginosa. Specimens were infected for up to 14 days and degree of infection was monitored. E. faecalis; rapid infection of the whole length and survival after removal of nutrients. S. sanguis; 2 weeks for complete infection. E.coli; only penetrated 600µm. except for E.faecalis all other organisms died after 4 to 48 hrs. IKI more potent than NaOCl or CHI. Presence of smear layer delayed but did not eliminate the effect of the medicaments.

Answer 72

Orstavik and Haapasalo, 1990,

Question 73

Endodontic leakage studies reconsidered More research is needed on the methodology of leakage studies. Way too many studies in the 80 and 90s with varying results that provide little relevant information.

Answer 73

Wu and Wesselink, 1993, IEJ

Question 74

The Balanced force concept for instrumentation of curved canals. Balanced force was derived from the law; for every action there is an equal and opposite reaction. Magnitude of the restoring force is a function of: File's mass Geometry composition Radius and arc of instrumentation curve. Placement is accomplished using CW rotation no more than 180 degrees with light inward pressure. Cutting is accomplished using CCW rotation of at least 120 degrees and inward pressure. Cleaning or debris removal is accomplished using one or two non cutting, no pressure outward pull clockwise rotation. Balance force allows you to produce enlargement of canals past severe curvatures.

Answer 74

Roane, 1985, JOE

Question 75

Bacteriologic evaluation of math effect for 0.5 % NaOCl in endodontic therapy. No bacteria could be recovered from 12 out of 15 root canals at the fifth appointment when NaOCl was used No bacteria could be recovered from 8 out of 15 root canals when saline was used NaOCl is more effective than saline. 88% of strains recovered were anaerobic. Most common; F. nucleatum Closed RCS seems to be a selective milieu where the composition of the flora is influenced by: Changes in anaerobiosis. nutritional interrelationships. More studies are needed to evaluate higher concentrations of NaOCl.

Answer 75

Bystrom, 1983, OOO

Question 76

Mesiodistal and buccolingual roentgenographic investigation of 7275 root canals. Apical Exit: 16.9% Lateral exit: 83% (6018 Canals) Apical foramen diameter increases with age Most canals are curved and cone shaped.

Answer 76

Pineda and Kutler, 1972, OOO

Question 77

An evaluation of microbial leakage in roots filled with Resilon. compare bacterial leakage through GP and resilon using S. mutant and E. faecalis. Resilon; thermoplastic synthetic polymer of polyester. Epiphany; Dual cure dental resin composite sealer. 40 sec of light will cure the coronal 2 mm, entire fill will cure in approx 15 to 30 min. Resilon can be removed with chloroform. Resilon is very compatible since it can be used for tissue engineering but it can also be degraded by the body. Polymerization is never 100% Resin tags into dentin to form mono block.

Answer 77

Shipper, 2004, JOE

Question 78

Sealing ability of MTA for repair of lateral root perforations Comparison of amalgam, IRM and MTA 50 extracted teeth were repaired after creating a lateral root perforation and them placed in saline for four weeks. Factors that affect prognosis of repair Contamination of perforation site Location Size Operator skill Material of choice. MTA performed better than the other two materials.

Answer 78

Lee, 1993, JOE Torabinejad was the third author

Question 79

A comparison of RC preparations using NITI hand and engine driven and k-flex endo instruments. Canal curvature and shape: no significant difference with the different instruments. Canal transportation; Less with NITI rotary instruments. SS instruments are able to negotiate obstructions better because they do not bend, also better tactile sensation.

Answer 79

Glosson, 1995, JOE

Question 80

Coronal leakage as a cause of failure in RCT. A review More important to seal the coronal part of molars with glass ionomer due to the presence of accessory canals in this area It is important to remove the smear layer because it can be broken down by bacterial toxins Crown of tooth should be restored expeditiously. Temp material should be at least 3.5 mm thick. Chemically active adhesives might play an important role in the future.

Answer 80

Saunders and Saunders, 1994

Question 81

Prevalence of Black-pigmented bacteroides species in root canal infections. Positive association between black-pigmented Bactroides species and apical abscess formation

Answer 81

Sundqvist, Johansson and Sjogren, 1989

Question 82

Root resorption - etiology, terminology and clinical manifestations. Classifications: Inflammatory; Precementum or Predentin become mineralized, could be internal or external. Either transient or progressive and it requires an intervention to stop it. Replacement; seen it teeth that have become ankylosed and incorporated into the bone. Transient; Occurs as a result of trauma, ortho, perio tx, self limiting to 2-3 weeks. Not clinically significant. Progressive inflammatory; due to continued stimulation to resorbing cells such as mechanical, pressure, infection or systemic diseases. Internal resorption; takes place w/i RCS after loss of predentin and odontoblast layer. uncommon in permanent teeth. external resorption; can be progressive, vertical or replacement.

Answer 82

Tronstad, 1988,

Question 83

Histologic assessment of MTA as a root-end filling in monkeys. MTA had cementum deposition and PDL attachment. Amalgam did not prevent micro leakage and did not allow for regeneration of dentinoalveolar tissues.

Answer 83

Torabinejad, 1997, JOE

Question 84

Investigation of Mineral Trioxide Aggregate for Root-End Filling in Dogs. Regeneration of cementum over MTA MTA is probably capable of the activation of cementoblast.

Answer 84

Torabinejad, 1995, JOE

Question 85

Biologic effects of dental materials. Toxicity and antimicrobial effect of endo antiseptics in vitro Toxic effects of NaOCl, CHI, Iodopax are 10X grater than their antimicrobial effects NaOCl at 5% is highly toxic and irritating to the tissue, dissolves necrotic and vital tissue. Lower concentrations should be considered. Chlorhexidine; low toxicity but minimal cleansing effect. Iodine solutions might discolor tooth and patient might be hypersesitive.

Answer 85

Spangber, 1973, OOO

Question 86

An Evaluation of Coronal Microleakage in Endodontically Treated Teeth. Part I. Time Periods Evaluation of micro leakage when obturation material are exposed to fluids. Significant amount of micro leakage is evident after three days of exposure to saliva.

Answer 86

Swanson and Madison, 1987, JOE

Question 87

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Answer 87

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Question 88

A Scanning Electron Microscopic Evaluation of Four Root Canal Irrigation Regimens. Compare debriment capabilities of saline, 5.25% NaOCl, 15% EDTA and combinations. EDTA removes smear layer but not organic material. NaOCl removes organic debris and its antibacterial but does not remove SL. Alternating EDTA and NaOCL effectively removes smear layer, tissue, predentin and increases antimicrobial activity

Answer 88

Baumgartner, 1987, JOE

Question 89

Bacterial leakage of mineral trioxide aggregate as a root-end filling material. Compare bacterial leakage potential of amalgam, Super-EBA, IRM, and MTA. EBA, IRM and amalgam showed leakage at 6-57 days. MTA showed no leakage at 90 days.

Answer 89

Torabinejad, 1995, JOE

Question 90

Cellular response to mineral trioxide aggregate. IRM; cytotoxic, cell death in three days when in contact. MTA; Biocompatible, cells remained healthy when in contact. Increases presence of presence of cytokines: IL1a, IL1b and IL6. promotes cytokine release from osteoblasts.

Answer 90

Koh, 1998, JOE Torabinejad was fifth author.

Question 91

Post Placement and Restoration of Endodontically Treated Teeth. Retrievability easiness; metal\>fiber\>ceramic/zirconium basically impossible Post length should be equal to ¾ length of the root or at least the length of the crown but no less than 8mm or longer than 4 to 5 mm from apex to maintain adequate seal. A 1 mm of vertical height ferrule doubles the resistance to fracture. Maximum benefit achieved with 1.5 to 2 mm ferrule

Answer 91

Schwartz, 2004, JOE

Question 92

Taxonomy, ecology and pathogenicity of the root canal flora. The bacterial synergy is an important factor in determining the pathogenicity of the polymicrobial root canal floral Most common bacteria; Peptostreptococci (micros and anaerobicus ) · Gram pos, anaerobic, non spore forming. Most frequently isolated species from intact canals; Fusobacterium nucleatum Most common in treatment failure; A. israelii due to its ability to establish infections in the periapical tissues.

Answer 92

Sundqvist, 1994,OOO

Question 93

Ecology of the root canal flora. The factors may influence the ecology of the root canal bacteria composition 1. Number of bacteria species is in proportion to the apical lesion size. 2. The root canal environment is dynamic and selective. (e.g. the relative proportion of anaerobic bacterial strains increased with time) 3. Bacterial interrelationships: both positive and negative influences (e.g. F. nucleatum is positively related to P. micros, W. recta, P. endodontalis, and S. sputigena) (e.g. A. israelii is positively related to P. propionicus,) 4. Nutrition supply: different phase of infection provides different kind of nutrition to bacteria First: Glucose/F. Nucleatum Second: Glycoproteins/B. Intermedius Third: Amino acid and peptide/P. Micros 5. Bacteriocins: Some species produce bacteriocins (protein) and inhibit other species (e.g. P. endodontalis inhibits the growth of B. intermedius) 6. Endodontic treatment

Answer 93

Sundqvist, 1992, JOE

Question 94

Dye Leakage of Four Root End Filling Materials: Effects of Blood Contamination. MTA leaked significantly less than other tested materials as an retro-filling material, and the result was not affected by blood contamination

Answer 94

Torabinejad, 1994, JOE

Question 95

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Answer 95

Reset

Question 96

Dentinal Fluid Dynamics in Human Teeth, In Vivo 5 first and second mandibular bicuspids in children 12-15. Class V preparation. Hydraulic apparatus to evaluate pulpal pressure in vivo All five teeth exhibited an outwardly directed fluid flow when exogenous pressure was set at 0. Mean value of the spontaneous fluid flow was 0.36µl min-1 cm-2 .

Answer 96

Ciucchi, 1995, JOE

Question 97

Reduction in Tooth Stiffness as a Result of Endodontic and Restorative Procedures.

Answer 97

Ree, 1989, JOE

Question 98

Current Challenges and Concepts in the Preparation of Root Canal Systems: A Review Main issues • Identification, accessing, and enlargement of the main canals without procedural errors • Establishing and maintaining adequate working lengths through- out the shaping procedure • Selection of preparation sizes and overall geometries that allow adequate disinfection and subsequent obturation. Results. NiTi instruments clinically showed a low incidence of preparation errors, satisfactory obturation as judged from radiographs, and significantly improved healing com- pared with a control group treated with stainless-steel instruments

Answer 98

Peters, 2004, JOE

Question 99

Defects in Rotary Nickel-Titanium Files After Clinical Use 378 used files analyzed, used by one endodontist. 50% showed some defect 21% were fractured, of those Torsional fracture = 56% perhaps due to too much apical pressure during instrumentation. Flexural fatigue = 44% usually in larger instruments, just like Pruett study Conclusion; Use light apical pressure. Do not keep instrument rotating in the same position for an extended period of time. Examine each instrument before use.

Answer 99

Sattapan, 2000, JOE

Question 100

Cytotoxicity of four root end filling materials. Compared; Amalgam, EBA, IRM and MTA Amalgam was less cytotoxic fresh and set followed by MTA. 24 hrs later from less to most cytotoxic: Amalgam, MTA, EBA, IRM

Answer 100

Torabinejad, 1995, JOE

Question 101

Use of MTA for the repair of furcal perforations. 30 furcal perfs on 7 beagle dogs. As per Ingle, perforations are the second greatest cause of failure; 10%. Perf of apical and middle third have a better prognosis. Favorable response to MTA if filled immediately, including cementum formation over MTA and PDL attachment. Poor prognosis due to infection if repair is delayed, epitheleal proliferation was seen in this group.

Answer 101

Ford, 1995, OOO Torabinejad is second author

Question 102

Analysis of stress distribution by endodontic posts threaded posts generate a high level of stress but best stress distribution at short lengths. Tappered posts exhibit a wedging effect. Parallel posts generate the highest apical stress.

Answer 102

Standlee and Caputo, 1972

Question 103

Endodontic success, Who is reading the radiograph. 6 examiners, 253 cases. Agreement was reached in less than half the cases.

Answer 103

Goldman, 1972, Tufs

Question 104

Microbial status of apical root canal system of human mandibular first molars with primary apical periodontitis after “one-visit” endodontic treatment. anatomical complexity of the RCS and organization of microflora under biofilm prevent the complete removal by instrumentation and irrigants in a single visit.

Answer 104

Nair, 2005