microbiology

Question 1

microorganisms from the root canal of the tooth can invade periapical endodontic lesions of asymptomatic teeth and establish an infectious disease process extraradiculary

Answer 1

Sunde et al 2002

Question 2

Root canals of all periapically affected teeth contain bacteria.
Only a small fraction of the periapical lesions reveals bacteria within the body of the lesions.

Answer 2

Nair 1987

Question 3

Accessed and severed monkey pulps. Some sterile, some infected by oral bacteria. Sealed with temp for 6 mo. None of the sterile necrotic pulps showed PARL and remained sterile. Most of the infected necrotic pulps showed PARL. Argument against anachoresis. Also shows effectiveness of 3mm temp seal.

Answer 3

Moller, Fabricius, Dahlen 1981

Question 4

he foundation of endodontic pathosis…landmark article. Pulpal exposures were made in germ-free and conventional rats. Jaws and teeth sectioned at intervals. In conventional rats, all teeth showed pulpal necrosis and abscesses after day 8. In germ free rats, matrix formation and dentinal bridging occurred. No inflammation was found and none of the pulps were necrotic at 28 days, dentin bridging was complete at this time too. Therefore, pulpal infection is due to microbes.

Answer 4

Kakahashi, Stanley, Fitzgerald 1965

Question 5

Cultured prior to obturation:
• 94% w/ neg cultures were successful after 5 yrs.
• 68% of pos cultures were successful after 5 yrs.
Presence of cultivable bacteria sig affects the success rate. Big proponents of CaOH2 to kill remaining bacteria.

Answer 5

Sjogren 1997

Question 6

demonstrated that all cases with a periapical radiolucent lesion had microbes in the root canal system and there were always between two and twelve strains of bacteria present

Answer 6

Sundqvist 1976

Question 7

Bacterias can penetrate dentinal tubules and lateral canals.

Answer 7

Love 1996, Siqueira 1996

Question 8

External periapical resorption may partially or totally alter the border between the cementum and dentine apical, an anatomic reference for preparation of the root canal, and length of the root filling

Answer 8

Malueg et al. (1996

Question 9

Apical internal resorption was found in 74.7% of roots associated with periapical lesions.

Answer 9

Vier & Figueiredo(2004)

Question 10

exposed the dental pulps of conventional and germ-free rats to the oral cavity and reported that pulp necrosis and periradicular lesions developed only in conventional rats with an oral microbiota.

Answer 10

Kakehashi et al. (1965)

Question 11

Demonstrated that only devitalized pulps that were infected induced periradicular lesions, whereas devitalized and uninfected pulps showed absence of pathological changes in the periradicular tissues.

Answer 11

Möller et al. (1981)

Question 12

Confirmed the important role of bacteria in periradicular lesions in a study using human teeth, in which bacteria were only found in root canals of pulpless teeth with periradicular bone destruction.

Answer 12

Sundqvist (1976)