Literature 4

Question 1

Cvek 1992
Prognosis of lunated non-vital maxillary incisors treated with calcium hydroxide and filled with GP, a retrospective clinical study

Answer 1

Periapical healing 95% after CaOH2, 92% after GP, inflammatory root resorption apical lesion 97% healed after completion of CaOH2 treatment and 4 years after GP.
CaOH2 helps with short-term but long-term

Question 2

Rotstein 1996

Histochemical analysis of dental hard tissues following bleaching

Answer 2

changes in Ca/P ratio indicate alterations in the inorganic components of hydroxyapatite, Sulfur which present in the matrix of hard tissues, changes may indicate damage to the organic component of the matrix, Potassium present intercellularly. bleaching materials may adversely affect the dental hard tissues and should be therefore used with caution.
They tested all internal and external bleaching material on cementum and enamel

Question 3

Dorn 1990

Retrograde filling materials: a retrospective success-failure study of amalgam, EBA, and IRM

Answer 3

SuperEBA and IRM demonstrated statistically significant improvements in success rates when compared with amalgam. The prognosis for the use of reinforced zinc oxide-eugenol cements (SuperEBA and IRM) as retrofilling materials appears favorable.

Question 4

Helfer 1972

Determination of the moisture content of vital and pulpless teeth

Answer 4

Goal of study was to compare moisture content of vital teeth, to teeth with pulp tissue removed
dog teeth, in vitro
Pulpless teeth found to have 9% less total moisture content than vital teeth
Free water content is 1.367% less in pulpless teeth

Question 5

Magura 1991

Human saliva coronal microleakage in obturated root canals: an in vitro study

Answer 5

Coronal leakage of saliva can be significant after only 3 months of temporary restoration as measured by dye penetration in the study. Caution should be taken with obturated canals exposed to oral cavity >3M. Dye penetrates further than the bac because dye has smaller particles

Question 6

Hancock 2001

Bacteria isolated after unsuccessful endodontic treatment in a North American population

Answer 6

E. faecalis
paper points and last file two techniques
Significant increase in the amount of bacteria recovered from canal if pretreatement root filling material was between 2-4 mm from apex or if the size of the apical lesion was > 5mm.
No E. faecalis was recovered from teeth that were treated with CaOH during initial treatment.
Their conclusion should not generalize E. faecalis to all facultative anaerobic
E. faecalis might be entering the canal system during treatment due to inadequate aseptic technique and/or poor temporary between appointments.
This would be one of the references that I can use to justify whether planning on using medicaments or not in between visits

Question 7

Esposito and Cunningham, 1995

Comparison of Canal Preparation with Nickel- Titanium and Stainless Steel Instruments

Answer 7

File size #25 and #30; No significant difference found between the ability to maintain the canal shape between the three groups was found.
File size #35, #40 ; SS maintained the original path in 11/15 and 10/15 cases respectively; NITI hand and rotary instruments maintained original path in all cases.
NITI instruments are able to maintain the original curvature of the canal at sizes that SS usually cannot.

Question 8

Torabinejad 1995
Comparative Investigation of Marginal Adaptation of Mineral Trioxide Aggregate and Other Commonly Used Root-End Filling Materials

Answer 8

MTA provides better adaptation and seal than commonly used root-end filling materials.
MTA showed the smallest gap between material and dentin walls followed by amalgam.

Question 9

Pashley 1986

Dentin Permeability, Dentin Sensitivity, and Treatment Through Tubule Occlusion

Answer 9

Dr. Brannstrom reviewed the evidence in support of the hydrodynamic theory of dentinal pain. Hydrodynamic theory: movement of dentinal fluid or tubule contents occurs in response to tactile, thermal, or osmotic stimuli.
The hydrodynamic theory of dentin sensitivity states that movement of tubule contents or tubule fluid, in either direction, causes dentin sensitivity.
The use of potassium oxalate as a desensitizing agent combines the tubule-occluding properties of calcium crystals, with the inhibitory property of potassium on intradental nerves.
The fact that many of the agents that are used clinically to desensitize dentin are also effective in reducing dentin permeability tends to support the hydrodynamic theory.
Flow out when it’s cold.
When tooth loses its enamel, the flow is much greater and it’s more sensitive

Question 10

Brännström 1966

Sensitivity of dentine

Answer 10

fluid and odontoblasts processes are extending into the dentinal tubule
Heat, inward direction
an article to support hydrodynamic theory

Question 11

Baumgartner & Falkler 1991 JOE

Bacteria in the apical 5 mm of infected root canals

Answer 11

Root canal infection is polymicrobial, and anaerobic species can be observed in all the samples. primary infection

Question 12

Smith et al. 1993 IEJ

Factors influencing the success of conventional root canal therapy – a five-year retrospective study

Answer 12

Multiple factors may affect the endodontic treatment success rate, but obturation material may not be one of them.

Question 13

Wu 1992

Fluid transport and bacterial penetration along root canal fillings

Answer 13

Air entrapment hinders in both the mechanism hence lot of studies can have varied results.
Suggested: Criterion for ‘bacteria tight’ (BT), set at a void diameter of 2 um requires atz least 24 h for one reading of the position of the air bubble in the capillary tube.
The specimens that are ‘non-bacteria tight’ may have void with diameters < 2 rendering them impassable for bacteria.

Question 14

Nair 1987

Light and Electron Microscopic Studies of Root Canal Flora and Periapical Lesions

Answer 14

The purpose of this communication is to study the endodontic and periapical flora of diseased human teeth using correlated light and transmission electron microscopy.
The endodontic flora was often seen against a dense wall of PMN’s.
The rods often showed Gram-negative cell walls.
oot canals of 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 symptomatic.

Question 15

Bramante et al JOE 1987

A Methodology for Evaluation of Root Canal Instrumentation

Answer 15

his procedure provided the original area of the root canal (anatomical area) and the instrumented root canal (operative area) so that the differences between both areas could be compared
Sectioned teeth

Question 16

Sedgley et al JOE 1992

Are Endodontically Treated Teeth more Brittle?

Answer 16

There were no statistically significant differences between endodontically treated and contralateral vital teeth in punch shear strength and toughness
load to fracture values were not significantly
microhardness values for vital teeth were statistically significantly higher than contralateral endodontically treated teeth, this small difference (3.5%) is unlikely to be clinically significant

Question 17

Dederich, JOE 1984
Scanning electron microscopic analysis of canal wall dentin following neodymium- yttrium-aluminum-garnet laser irradiation.

Answer 17

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.

Question 18

Torabinejad Et. Al 2003

A new solution for the removal of the smear layer.

Answer 18

he results show that MTAD is an effective solution for the removal of the smear layer and does not significantly change the structure of the dentinal tubules when canals are irrigated with sodium hypochlorite and followed with a final rinse of MTAD.

Question 19

Influence of coronal restorations on the periapical health of endodontically treated teeth
Tronstad L et al 2000

Answer 19

No timeline follow. The cases were all done at different timing
• Endo is more important than coronal restoration when the periapical status was evaluated
• The presence of a post did not affect the endodontic success rate negatively in any of the combinations

Question 20

Tay, Pashley 2005

Geometric Factors Affecting Dentin Bonding In Root Canals: A Theoretical Modelling Approach

Answer 20

C-factor
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

Question 21

Meister & Lommel- 1980

Diagnosis and possible causes of vertical root fractures

Answer 21

Vertical fractures always start from apex
Displacement of the root
Osseous defect observed in 30/32, in the other 2 not enough time elapsed for bone loss to occur
Vertical bone loss occurred in the area of vertical root fracture to the deepest point of the fracture line

59 % of cases occurs in the pts over 50 yrs old
excessive force during lateral condensation of the gutta-percha and excessive force in seating Silver cones are the major causes of vertical root fractures.
Forcing or tapping inlays or dowels into place and over preparation of dowel space
are suggested as secondary causes.
excessive force during lateral condensation of the gutta-percha and excessive force in seating Silver cones are the major causes of vertical root fractures.
Forcing or tapping inlays or dowels into place and over preparation of dowel space
are suggested as secondary causes.