Qualitative changes of the pulp and multiple electric measurement of the canal

U cilju analize faktora koji utječu na rezultat mjerenja dužine kanala promjenu broja i odnosa čestica s električnim nabojem, analizirali smo pomoću bioelektričnog potencijala, električne vodljivosti i mjerenjem koncentracije anorganskih kationa: Na+, K+, Ca++ i Mg++ metodom AAS. Uspoređivanjem vrijednosti bioelektričnog potencijala između gin­give i eksponirane pulpe, mogli smo razlikovati skupine: jednaki potencijali-normala, povišeni i sniženi. Normala električne vodljivosti izmje­rena je na zdravoj gingivi (test mjerenja) kao granična vrijednost između pulpnog i periapeksnog tkiva, i to znači da se proširivač sa stoperom br. 15 utiskuje kroz vitalnu pulpu do test vrijednosti. Udaljenost od vrha proširivača do stopera je prva dužina kanala (d1). Nakon provedene ekstirpacije mjeri se drugi put (d2), a prije punjenja treći put (d3). Toč­nost punjenja ocijenjena je rendgenogramom. U istraživanju je bio 41 pacijent sa 81 mjerenjem kanala, a u 18 eksperimentalnih pulpi izvršena je analiza kationa. Suma analiziranih kationa u skupini normala potencijala je 68,96 mg/g, postotak suhe tvari 22,24%, točnosti d1 mjerenja sa ±SE je 50 ±12%, a d2 + d3 je 81 ± 9,76. U skupini povišeni je Σ kationa 67,89, suha tvar 28,27%, 20 ± 8,7%, a d2 + d3 je 78 ± 5,86%. U skupini sni­ženi kationa je 61,59, suhe tvari 32,60%, d1 40 ± 7,0%, d2 + d3 je 80 ± ±10,33%. Povoljni rezultati u toku višestrukog mjerenja nisu slučajni (P <0,01). Presudni utjecaj na rezultat imaju nastale kvalitativne promjene pulpe.The aim of this study was to analyze the factors influencing the results of the canal length measurements and changes in the number of particles and their relations to the electric charge. Therefore, they were assessed using the features of bioelectric potential and electric conduc­tivity, and measuring the concentrations of inorganic cations, i.e. Na+, K+, Ca++ and Mg++ by the AAS method. Comparing the bioelectric poten­tial values between the gingiva and the exposed pulpa, the following groups were obtained: equal potentials — normal, elevated and lowered poten­tials. The normal electric conductivity value was measured in healthy gin­giva (measuring test) as a borderline value between the pulpal and periapical tissue, which means that an extender with a No 15 stopper was impressed through the vital pulp up to the test value. A distance between the tip of the extender and the stopper was the first canal length (d1). The second length measurement was carried out following extirpation (d2), and the third one before filling (d3). The accuracy of fil­ling was evaluated by means of a roentgenogram. Forty-one patient with 81 canal measurements were included in the study. Cations were ana­lyzed in 18 extirpated pulps. The sum of cations analyzed in the group of normal potentials was 68.96 mg/g, dry substance percentange 2.24%, d1 measurement accuracy ± SE = 50 ± 12%, and d2 + d3 = 81 ± 9.76%. In the group of elevated potentials, the sum of cations was 67.89, dry subtance percentage 28.27%, d1 = 20 ± 8.7% and d2 + d3 = 78 ± 5.86%. In the group of lowered potentials, the sum of cations was 61.59, dry substance percentage 32.60%, d1 = 40 ± 7.0%, and d2 + d3 = 80 ± 10.33%. Good results obtained by multiple measurements should by no means be considered casual (P