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Azerbaycan Saytlari

 »  Home  »  Endodontic Articles 9  »  The effect of instrument type and preflaring on apical file size determination
The effect of instrument type and preflaring on apical file size determination
Results.



A total of 121 canals were utilized for analysis. Canal sizes are expressed either in ISO sizes or in diameters (x10_2 mm) (e.g. an ISO size 10 is equal to a file tip diameter of 10 x10_2 mm); file sizes typically increase in increments of 5 ISO units, or 5 _10_2 mm. The mean _ standard deviation diameters registered were as follows (Table 2) - K( without flaring): 23.8 _7.1; LS (without flaring): 33.4 _8.6; K (with flaring): 29.2 _ 7.3; LS (with flaring): 38.5 _8.5.
Both the instrument type and flaring had a highly significant effect on apical size estimate (P < 0.001,anova). The mean diameter of canal measurement with the LS instruments was larger than with K-files by 9.4 _ 10_2 mm (P < 0.001; 95% confidence interval: 8.7 _ 10_2,10.2 _10_2). flaring hadan impact on apical sizing by both types of instruments. It resulted in an increase of average diameter of 5.3 _10_2 mm(P < 0.001;95% confidence interval: 4.5 _10_2, 6.0 _10_2). There was no interaction between instrument types and flaring (P > 0.05), which means that the difference between K- files and LS was consistent before and after flaring, and the effect of flaring was consistent in both instruments (Table 3). Hence, no post hoc tests (pair wise comparisons) were conducted. Also, linear regression analysis did not show a significant relationship between the initial canal size (K-file) and the difference (LS _ K) (r2 ј0.028, P > 0.05), indicating that the differences between K-files and LS instrument readings were consistent as canal size increases.

Table 2. Range of canal size and mean diameter (x 10_2 mm) as registered by K-files and LS instruments before and after flaring (data for 121 canals).

Range of canal size and mean diameter as registered by K-files and LS instruments before and after flaring

Table 3. Range and mean diameter difference (x10_2 mm) between K-files and LS instruments used to determine apical canal size (data for 121 canals).

Range and mean diameter difference between K-files and LS instruments used to determine apical canal size

Effect of instrument type.
LS versus K-files Both before and after flaring, more than 90% of canals showed greater LS readings than the corresponding K- file readings (109/121 and 110/121 canals, respectively) (Figs 1and 2). The most common size difference (i.e. the mode) was 10 ISO units before flaring and 7.5 ISO units after flaring. The mean diameter differences of LS _ K were 9.6 _10_2 mm before flaring and 9.3 _10_2 mm after flaring, or approximately two file sizes (10 ISO units) larger (Table 3).

Effect of flaring.

After flaring versus before flaring.
Flaring resulted in an increase of the file size reading for both K-files and LS instruments. A large majority of the canals with K-file (77.7%) and LS (61.9%) registered at least one file size larger after flaring. The mean diameter differences after flaring versus before flaring were 5.4 _10_2 mm for K-file and 5.1 _10_2 mm for LS instruments, or approximately one file size (5 ISO units) larger (Table 3).

Figure 1. Scatter plot of apical file sizes registered for LS versus K-file (without flaring) (total:121canals). Points above the line indicate a larger LS size; points below the line indicate larger K-file size. Note that many of the points are superimposed so that all the 121 points are not visible.

Scatter plot of apical file sizes registered for LS versus K-file

Figure 2. Scatter plot of apical file sizes registered for LS versus K-file with flaring (total: 121 canals). Points above the line indicate a larger LS size; points below the line indicate larger K-file size. Note that many of the points are superimposed.

Points above the line indicate a larger LS size; points below the line indicate larger K-file size