Influência da terapia endodôntica e do envelhecimento artificial acelerado na resistência de união de pinos de fibra de vidro à dentina intrarradicular
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2012-05-28
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Universidade Federal de Goiás
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Aim: To evaluate in vitro the influence of root canal instrumentation techniques,
endodontic irrigants, endodontic sealers and artificial accelerated aging on
fibreglass post bond strength to bovine intraradicular dentine. Methodology:
Part 1. 120 bovine incisors were divided into 12 experimental groups (n=10)
resulting from the interaction among 3 study factors: root canal instrumentation
technique (RCPSS- root canal preparation with stainless steel instruments - KFile;
RCPNiTi- root canal preparation with K3 Nickel-Titanium instruments),
endodontic irrigant (NaOCl- 1% sodium hypochlorite; CHX- 2% chlorhexidine;
O3- 1.2% ozonated water) (in all samples 17% EDTA was used to remove the
smear layer) and specimens artificial accelerated aging (Immediate, test with no
aging; Mediate, test performed after 2 months of water storage at 37°C). After
root canal preparation, endodontic filling was not performed. Fibreglass posts
were cemented with self-adhesive resin cement (RelyX U100, 3M-ESPE) and
roots were cross-sectioned to obtain two slices of each third. Samples were
submitted to micropush-out test and bond strength values (MPa) were analyzed
by ANOVA in a split-plot arrangement and Tukey’s test (α = 0.05). Failure
modes were evaluated under a confocal microscope. Part 2. 60 bovine incisors
were divided into 6 experimental groups (n=10) resulting from the interaction
between 2 study factors: endodontic sealer (Sx- Sealapex; S26- Sealer 26; AHAH
Plus) and specimens artificial accelerated aging (Immediate, test with no
aging; Mediate, test performed after 2 months of water storage at 37°C). Two
control groups were employed (without root canal filling), represented by groups
RCPNiTiNaOCl immediate and RCPNiTiNaOCl mediate of part 1 of the present
study. In the six experimental groups, root canals were prepared 1mm from the
apex with K3 Nickel-Titanium instruments associated with 1% sodium
hypochlorite irrigation and 17% EDTA. They were then filled with gutta-percha
and the specific sealer of each group, using the lateral compaction technique.
Fibreglass posts were cemented with self-adhesive resin cement (RelyX U100,
3M-ESPE) and roots were cross-sectioned to obtain two slices of each third.
Abstract xx
Samples were submitted to micropush-out test and bond strength values (MPa)
were submitted to ANOVA in a split-plot arrangement and Tukey’s test (α =
0,05). Comparisons with control groups were made using Dunnet test (α = 0.05).
Failure modes were evaluated under a confocal microscope. Results: Part 1. In
specimens submitted to water artificial aging, RCPNiTi presented higher bond
strength values than RCPSS in apical third irrigated with NaOCl or CHX.
Irrigation with NaOCl resulted in higher bond strength than O3. Artificial aging
resulted in significant bond strength increase, except for middle and apical thirds
of RCPSSO3 and apical of RCPNiTiO3. Bond strength significantly reduced in
apical third. The prevalence of adhesive cement-dentine failure was verified in
all groups. Part 2. Endodontic sealers showed no significant differences among
them, however they presented significantly lower bond strength values than
control groups (without filling), except in cervical third of groups tested
immediately. Artificial aging did not interfere on bond strength to intraradicular
dentine. There was a significant decrease on bond strength from cervical to
apical third. The prevalence of adhesive cement-dentine failure was verified in
all groups. Conclusions: Part 1. Root canal preparation with NiTi instruments
associated with NaOCl irrigation and EDTA increased the bond strength of
fiberglass posts cemented with self-adhesive resin cement to intraradicular
dentine. Part 2. Endodontic sealers interfered negatively on bonding of
fibreglass posts cemented with self-adhesive resin cement to intraradicular
dentine.
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SANTANA, Fernanda Ribeiro. Influência da terapia endodôntica e do envelhecimento artificial acelerado na resistência de união de pinos de fibra de vidro à dentina intrarradicular. 2012. 140 f. Tese (Doutorado em Ciências da Saúde)–Universidade Federal de Goiás, Goiânia, 2012.