Top 100-100 Flashcards
- Tay, 2005, JOE
Geometric Factors Affecting Dentin Bonding in Root Canals: A Theoretical Modeling Approach. To estimate influence of geometric variables ( C-Factor, thickness and volumetric shrinkage of sealer, root canal dentine) in resin bonding to root dentine. Polymerization stresses exceed bond strength of resin to dentine à debonding to relieve stresses · Thicker sealer reduces C-Factor · Increase in file size caused only modest increase in C-Factor · High C Factor is a major obstacle for producing gap free adhesive fillings in root canals
- Cvek, 1992, EDT
Prognosis of luxated non-vital maxillary incisors treated with calcium hydroxide and filled with gutta-percha, A retrospective clinical study. 885 luxated incisors CaOH for 24 months for immature teeth 11 months for mature teeth then obturation with GP. follow up after CaOH and then 4 yrs after obturation. PA healing 95% after 4 yrs PA healing 92% Inflammatory root resorption stoped in 97%.
- Rotstein, 1996, JOE
Histochemical analysis of dental hard tissues following bleaching. 21 extracted human teeth treated with different bleaching agents. immersed in this materials and incubated for 7 days. bleaching materials may adversely affect hard tissues but study was done on extracted teeth and specimens were in bleaching agent for seven days. Not realistic.
- Dorn and Gartner, 1990
Retrograde filling materials, A retrospective success-failure study of amalgam, EBA and IRM. radiographs of 488 cases followed from 6 months to 10 years. Success rates: Amalgam; 75% IRM; 91% EBA; 95% Prognosis with materials containing SOE appear favorable.
- Dederich, 1984, JOE
SEM of canal wall dentin following laser irradiation. Canal wall dentin was lasered with the Nd-YAG laser at various time durations and power levels. It was found that such dentin could be melted and that it would recrystallize into a nonporous “glazed” surface
- Torabinejad, 2003
A new Solution for the removal of the smear layer. Investigate the effects of MTAD as a final rinse. 48 extracted teeth. MTAD is an effective solution for the removal of the SL and does not significantly change the structure of the tubules as compared to the severe erosion caused by EDTA.
- Helfer, 1972, OOO
Determination of the moisture content of vital and pulples teeth. 36 teeth from one dog extracted from 0-24 weeks. Water content was determined by weight after heating tooth. Pulpless teeth have 9% less moisture than vital teeth in calcified tissues. Statistically significant, but is it clinically significant?
- Magura, 1991, JOE
Human saliva coronal micro leakage in obturated root canals. Saliva penetration at three months was significantly greater than at previous intervals. Retreatment should be considered then.
- Hancock, 2001, OOO
Bacteria isolated after unsuccessful RCT in a North American population. 54 teeth with PARL selected for retreatment. Sampled under aerobic and anaerobic conditions. Study compared results of bacterial culturing of Scandinavian population in which the use of CaOH is routine and North American populations in which is not. Bacterial samples were very similar. E. faecalis was identified in 30 of cases.
- Esposito and Cunningham, 1995, JOE
A comparison of canal preparation with NITI and SS instruments. 45 extracted teeth with curvatures bn 20-45 degrees
- Goldman, 1972, Tufts
Part 1, 6 examiners diagnosed success-failure-questionable based off radiographs. Among all 6 of them, 47% of the time, they agreed with each other. Part 2, two endodontists were shown cases they did 7 months ago, and they with themselves 72% of the time.
- Zehnder, 2006
Root canal irrigants review. Sodium Hypochlorite is the bomb. Action on biofilm, tissue dissolving capacity, and action on organic compounds of smear layer. EDTA and citric acid works on inorganic components of smear layer.
- Bramante, 1987
Proof of concept for comparing RC anatomy before and after instrumentation. Mounted teeth in acrylic blocks, sectioned, took photograph, mounted again, instrumented, separated the sections and took final photographs for comparison.
- Brannstrom, 1966
Class V cavities were prepped, elicited pain, extracted teeth right away and sectioned for histological studies. Cold and pressure caused outward movement of odontoblast nuclei, heat caused inward movement. Supporting hydrodynamic theory. Tome’s fiber might not directly cause pain but trigger nerve fibers in pulp.
- Baumgartner, 1991, JOE
Bacteria in the Apical 5 mm of Infected Root Canals
10 Freshly extracted teeth with caries and PARL were cultured anaerobically and aerobically. Apical 5 mm.
Most prominent bacteria: Actinomyces, Lactobacillus, Black pigmented bacteroides.
68% were strict anaerobes.
Demonstrates ther presence of mostly anaerobic bacteria in the apical 5 mm.
- Wang and Hume, 1988
Weak organic acid (like in bac.) and alkaline (like ZOE, zinc phosphate, CaOH2, and dycal) are more ready to penetrate dentine due to buffering capacity of hydroxyapatite
- Smith, 1993, IEJ
Factors influencing the success of conventional root canal therapy—a five-year retrospective study
Type of obturation material had no demostrable effect on the success rate but the following factors did:
Age
Sex
Preoperative viatility
Periapical pathology
Overall success rate = 84%
- Spangberg, 1973
Tested cytotoxicity of obturation materials on Hela cells and found GP is the best. Chloropercha after chloroform evaporates, is the least toxic.
- Heikel, 1999
Pruett
- Pashley, 1990
Microleakage review. Dental pain and pupal pain are due to dentinal permeability
- Goerig, 1982
Step down in coronal and midroot, step back in apical
- Segley, 1972
Are Endodontically Treated Teeth more Brittle?
Comparisons of biomechanical properties of RCTT and non RCTT.
Properties; Shear strengh, toughness, hardness, load to fracture.
Differences between the two groups was not significant, meaning that RCTT are not more brittle than their counterparts, so other factors may more critical to failure of RCTT.
- Mader and Baumagartner, 1984
SEM, nasty pictures of smear layer. Used NaOCl, no EDTA, smear layer was 1-2 um in thickness and plugged into dentinal tubules up to 40 um.
- Wu, 1993
Fluid transport and bacterial penetration along root canal fillings.
Designed aparatus to observe the convectice transportation of water from coronal to apical end via a capillary tube with an air bubble.
These findings indicate that fluids tran^wrt through obturated root canals, most of which do not allow the passage of bacteria.
- Stanley and Lundy, 1972
Dycal is an acceptable pulp capping material that can stimulate dentin bridge formation by 23 days post-operatively. Dentin bridge forms in contact with Dycal. Pulpotomy should be considered over pulp capping if thickness of remaining pulp is 0.5mm or less.
- Peciuliene, 2001
In chronic apical periodontitis cases, IKI works better than CaOH2 in removing yeasts as well as G- enteric (E. Faecalis).
- Griffee, 1980
B. Melaninogenicus is the bac. that causes foul oder, pain, sinus track and apical sensitivity or swelling in nonvital teeth. “black giraffe”
- Pinheiro, 2003
Failed RCT, recovered facultative anaerobe 57%, G+, 83%, obligate anaerobes associated with pain
- Torabinejad, 2002
Smear layer review. Laying the ground for MTAD coming.
- Nair, 1987
Light and Electron Microscopic Studies of Root Canal Flora and Periapical Lesions.
All periapically affected teeth contain bacteria.
The endodontic flora consists of a mixture of cocci, rods, filamentous forms, and spirochetes. Only a small fraction of the periapical lesions reveals bacteria within the body of the lesions. Such lesions are invariably acute and symp- tomatic
- Sen, 1995
Smear layer is a “sen”. Cannot serve as a strick bac. barrier, disintegrate overtime, risk of reinfection of dentinal tubules after smear layer is remved.
- Mader and Baumagartner, 1984
SEM images of smear layer. Used 5.25% NaOCl but no EDTA
- Shuping, 2000, and Trope
Niti, rotary, 1.25% NaOCl, significant greater pattern of reduction of bacteria than using saline. After instrumen- tation with NaOCl irrigation, 61.9% of canals were rendered bacteria-free. The placement of calcium hydroxide for at least 1 wk rendered 92.5% of the canals bacteria free.
- Thompson, 2000
Overview of nickel-titanium alloys used in dentistry. Shape memory, super-elasticity, transformation temperature range (TTR), Martensitic phase, Austenite (super-elasticity, higher temperature), stress-induced martensitic transformation
- Madison, 1988
Madison, Mad money, microleakage, in the mad 80s.
In vivo study, dye penetration occurred in all groups with considerable variability within groups.
The presence of coronal microleakage as demonstrated by dye penetration after exposure of the root canals to the oral cavity should alert the clinician to this route as a potential etiology for root canal treatment failure.
exposed to saliva for 1 wk
- Senia, 1971
Clorox is more effective than saline in dissolving pulp tissue but limited effect at 1mm, and 3mm level or within isthmus. More effective in larger diameters than the smaller ones.
- Sarkar, 2005
Physicochemical basis of MTA. MTA is a mechanical mixture of three powder ingredients: Portland cement (75%), bismuth oxide (20%), and gypsum (5%). In contact with an STF, MTA’s surface layer dissolves (bio-active), releasing all of its major cationic components and triggering the precipitation of HA on its surface and in the surrounding fluid.
- Siren, 1997, Haapasalo
More visits, more enteric bacteria
Unsealed, more enteric bacteria
Retreat, more bac. Enterococcus faecalis
- Love, 2001
The results of the present study demonstrate that E. faecalis cells remain viable, and maintain the capability to invade dentinal tubules and adhere to immobilized type 1 collagen in the presence of human serum.
- Thompson and Dummer, 1997
Series 29, Step down, 20-40 degree. To determine the shaping ability of profile .04 taper 29 NI-TI instruments in simulated canals in clear resin blocks
Profile.04 taper series 29 rotary niti instruments prepared simulated canals rapidly and created good 3D form. A substantial number of instruments deformed
Canal shape did not influence significantly instrument deformation. Canal shape influenced the flow of the preparation. Larger ProFiles were associated with more deformation than the smaller instruments.
- White and Hays, 1997
CHX’s substantivity
2% better than 0.12%
Continue to release antibacteria effect 48-72 hours after instrumentation
- Foreman, 1990
CaOH2 review.
CaOH2 induced formation of fibrous tissue when in direct contact with tissues
The calcium ions in the mineralized content are not from CaOH2
CaOH2 is an initiator and a local buffer against inflammation
It neutralizes lactic acid produced by osteoclasts and prevent further destruction of bone
The high PH activate alkaline phosphataseactivity in bone formation
Optimum PH for alkaline phosphatase activity is 12
Calcium ions reduce the permeability of capillaries and maintain the concentration at mineralization site
Increased Calcium ions inhibits pyrophosphates (normal self-limiting enzymes for mineralization). Might cause uncontrolled mineralization of the pulp
Stimulate resorption, Andreasen 1981
- Safavi, 1990
Microbial growth were more frequently observed in Ca(OH)2 than IKI
Use IKI for infected cases, “flood” the canals for a few minutes
- Goldman, 1989
Dye studies should all use vacuum to remove air entrapment in order to be accurate
- Brannstrom, 1986
Hydrodynamic theory
- Pashley. 1986
Dentin Permeability, Dentin Sensitivity, and Treatment Through Tubule Occlusion
Hydrodynamic theory states that fluid movement causes dental sensitivity, then anything that decreases the movement of this fluid should reduce dentinal sensitivity.
Physiochemical mechanismis:
Growth of intratubular crystals from salivary or dentinal fluid mineral.
Adsorption of plasma proteins into tubules.
Smear layer.
Theurapeutic approaches:
Application of unfilled resins or oxalate salts to occlude tubules.
Goal is to restore original impermiability of tubules.
- Torabinejad, 1995
Comparative Investigation of Marginal Adaptation of Mineral Trioxide Aggregate and Other Commonly Used Root-End Filling Materials. (Amalgam, IRM, EBA)
88 freshly extracted teeth examined under SEM.
MTA had the smallest gaps (2.68 micrometers) and best marginal adaptation.
- Khayat, 1993
Torabinejad
Human Saliva Penetration of Coronally Unsealed Obturated Root Canals.
Determination of time needed for bacteria in saliva to contaminate entire root canal via the apparatus Torabinajad designed.
All root canals were contaminated within less than 30 days.
No significant difference between teeth obturated via lateral or vertical condensation.
- Meister, 1990
Diagnosis and possible causesof vertical
root fractures.
32 cases of vertical root fractures, all verified by surgery.
Vertical root fractures are:
Ussually associated with RCTT.
Have a diffused RL area of the periodiontium.
Defects can be proved.
Pain is usually minimal or completely absent.
Major causes:
excessive force during lateral condensation or seating silver cones.
Tapping or forcing inlays and dowels into place.
Overpreparation of post space.
- Tronstad, 2000
Influence of coronal restorations on the periapical health of endodontically treated teeth
1001 RCTT were radiographically examined as to the quality of the restoration and root canal.
GE + GR= 81%
GE + PR= 71%
PE + GR= 56%
PE + PR= 57%
GE= 78%
GR= 70%
