Effects of coronal leakage on concentration of hydrogen ions and calcium release of several calcium hydroxide pastes over different periods of time

Abstract

MSc,%Dental%School,%Redentor%School,%Itaperuna%,%RJ,%Brazil*% PhD,%Araraquara%Dental%School%<%Univ%Estadual%Paulista,%Araraquara,%SP,%Brazil**% PhD,%Dental%School,%Rio%Grande%do%Sul%Federal%University,%Porto%Alegre,%RS,%Brazil***% PhD,%Bauru%Dental%School%<%University%of%São%Paulo,%Bauru,%SP,%Brazil****% Correspondence:%miltoncarloskuga@hotmail.com%(KUGA%MC)%|%Received%23%Aug%2013%Received'in'revised'form%30%Aug%2013%Accepted%02%Sep%2013% % % CRESPO,%Mariana%Pires*% KUGA,%Milton%Carlos**% SÓ,%Marcus%Vinicius%Reis***% KEINE,%%Katia%Cristina**% SHINOHARA,%André%Luis****% % % % % % % % EFFECTS'OF'CORONAL'LEAKAGE'ON' CONCENTRATION'OF'HYDROGEN'IONS' AND'CALCIUM'RELEASE'OF'SEVERAL' CALCIUM'HYDROXIDE'PASTES'OVER' DIFFERENT'PERIODS'OF'TIME%% % ABSTRACT' % PURPOSE:% To% evaluate% the% effects% of% coronal% leakage% on% concentration%of%hydrogen%ions%(pH)%and%calcium%release%of%several% calcium% hydroxide% pastes,% over% different% periods% of% time.% MATERIAL' AND' METHODS:% % Fifty% extracted% human% mandibular% central%incisors%(n=10)%were%instrumented%up%to%the%F2%instrument% and% assigned% to% the% following% intracanal% dressing:% G1<% Calen,% G2<% Calen%with%0.4%%chlorhexidine%(CHX),%G3<%Calcium%hydroxide%with% camphorated% paramonochlorophenol% (CPMC)% and% glycerin,% G4<% Calen,% but% temporary% filling% material% maintained% during% all% test% (positive% control)% and% G5<% Root% canal% without% intracanal% dressing% (negative%control).%All%groups%were%immersed%in%distilled%water%for% 7%days.%In%sequence,%the%temporary%filling%materials%were%removed,% except%in%controls%groups.%All%specimens%were%individually%mounted% on% a% specific% device% and% only% its% root% again% immersed% in% distilled% water.% Concentration% of% hydrogen% ions% and% calcium% release% by% calcium%hydroxide%pastes%in%distilled%water%were%evaluated%in%24h,% 7,%14%and%28%days.%The%results%were%submitted%to%ANOVA%test%(p%=% 0.05).% After% 28% days,% root% canals% from% experimental% groups% were% examined% in% SEM.% RESULTS:% G1,% G2,% G3% and% G4% presented% similar% pH% values% and% calcium% release% and% did% not% differ% from% each% other% (p>0.05),% up% to% 7% days.% After% this% time% G1,% G2% and% G3% presented% values% lower% values% than% G4% (p<0.05).% In% SEM% analysis,% calcium% hydroxide% residues% were% observed% in% all% experimental% groups.% CONCLUSIONS:% After% 7% days,% coronal% leakage% decreased% the% concentration%of%hydrogen%ions%and%calcium%ion%release%provided%by% all%calcium%hydroxide%pastes.% ' ' ' ' ' ' KEYWORDS' % Calcium.%Camphorated%parachlorophenol.%Chlorhexidine.% Hydrogen.%Scanning%electron%microscopy.%