Materials and Methods

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4 Materials and Methods Study Design Specimen Preparation Canal Instrumentation Photos and Computer Imaging Manipulation of Images with Software Program Data Collection and Statistical Analysis

5 Materials and Methods Data Collection and Statistical Analysis All data were stored as image files and were entered into MS Excel The research question was to relate root anatomy and instrument characteristics to RDT or perforations

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8 Materials and Methods Data Collection and Statistical Analysis All possible two way interactions were included A repeated-measures ANOVA was performed for both outcome variables, mesial RDT and distal RDT

9 Materials and Methods Data Collection and Statistical Analysis Due to the small number of perforations (yes, no), they were described, but not statistically analyzed

10 Results Summary of canal pairings (Table 4) Data not analyzed (Table 5 & Table 6) Average post-op dentin thicknesses by groups (Table 7) Repeated-measures ANOVA (Table 8) Outcome: Post-operative distal dentin thickness (Table 9, Fig. 7) Outcome: mesial dentin thickness (Fig. 8 & Fig. 9) Outcome: Perforations (Table 10 & 11)

11 Results Summary of canal pairings (Table 4) Data not analyzed (Table 5 & Table 6) Average post-op dentin thicknesses by groups (Table 7) Repeated-measures ANOVA (Table 8) Outcome: Post-operative distal dentin thickness (Table 9, Fig. 7) Outcome: mesial dentin thickness (Fig. 8 & Fig. 9) Outcome: Perforations (Table 10 & 11)

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13 Results Summary of canal pairings (Table 4) Data not analyzed (Table 5 & Table 6) Average post-op dentin thicknesses by groups (Table 7) Repeated-measures ANOVA (Table 8) Outcome: Post-operative distal dentin thickness (Table 9, Fig. 7) Outcome: mesial dentin thickness (Fig. 8 & Fig. 9) Outcome: Perforations (Table 10 & 11)

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16 Results Summary of canal pairings (Table 4) Data not analyzed (Table 5 & Table 6) Average post-op dentin thicknesses by groups (Table 7) Repeated-measures ANOVA (Table 8) Outcome: Post-operative distal dentin thickness (Table 9, Fig. 7) Outcome: mesial dentin thickness (Fig. 8 & Fig. 9) Outcome: Perforations (Table 10 & 11)

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18 Results Summary of canal pairings (Table 4) Data not analyzed (Table 5 & Table 6) Average post-op dentin thicknesses by groups (Table 7) Repeated-measures ANOVA (Table 8) Outcome: Post-operative distal dentin thickness (Table 9, Fig. 7) Outcome: mesial dentin thickness (Fig. 8 & Fig. 9) Outcome: Perforations (Table 10 & 11)

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20 Results Summary of canal pairings (Table 4) Data not analyzed (Table 5 & Table 6) Average post-op dentin thicknesses by groups (Table 7) Repeated-measures ANOVA (Table 8) Outcome: Post-operative distal dentin thickness (Table 9, Fig. 7) Outcome: mesial dentin thickness (Fig. 8 & Fig. 9) Outcome: Perforations (Table 10 & 11)

21 Results Outcome: Post-operative distal dentin thickness Two main effects (Table 9) Two, two-way interactions (Only one is illustrated, (Fig. 7)

22 Results Outcome: Post-operative distal dentin thickness Two main effects (Table 9) Two, two-way interactions (Only one is illustrated, (Fig. 7)

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24 Results Outcome: Post-operative distal dentin thickness Two main effects (Table 9) Two, two-way interactions (Only one is illustrated, (Fig. 7)

25 Results Outcome: Post-operative distal dentin thickness Two, two-way interactions (Level of section*pre-op dentin thick) (Fig. 7) (Pre-op dentin thick*curvature) (not illus.)

26 Results Summary of canal pairings Data not analyzed Average post-op dentin thicknesses by groups Repeated-measures ANOVA Outcome: Post-operative distal dentin thickness Outcome: mesial dentin thickness Outcome: perforations

27 Results Outcome: mesial dentin thickness No main effects Two, two-way interactions (Curvature * Canal) (Fig. 8) (Pre-op dentin thick*gates) (Fig. 9)

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29 Results Outcome: mesial dentin thickness No main effects Two, two-way interactions (Curvature * Canal) (Fig. 8) (Pre-op dentin thick*gates) (Fig. 9)

30 Results Outcome: mesial dentin thickness No main effects Two, two-way interactions (Curvature * Canal) (Fig. 8) (Pre-op dentin thick*gates) (Fig. 9)

31 Results Outcome: mesial dentin thickness No main effects Two, two-way interactions (Curvature * Canal) (Fig. 8) (Pre-op dentin thick*gates) (Fig. 9)

32 Results Outcome: mesial dentin thickness No main effects Two, two-way interactions (Curvature * Canal) (Fig. 8) (Pre-op dentin thick*gates) (Fig. 9)

33 Results Summary of canal pairings Data not analyzed Average post-op dentin thicknesses by groups Repeated-measures ANOVA Outcome: Post-operative distal dentin thickness Outcome: mesial dentin thickness Outcome: perforations

34 Results Outcome: perforations

35 Results Outcome: perforations

36 Discussion Limitations Advantages and Disadvantages to Methods Used Comparison to Previous Studies

37 Discussion Limitations Advantages and Disadvantages to Methods Used Comparison to Previous Studies

38 Discussion Limitations The aim was to determine what anatomical characteristics and GGb size might be related to outcome of RDT or perforations. Root anatomy is complex Only tested factors were measured Other factors could include: force applied to hand piece, the physical properties of the dentin, the unique qualities of anatomy we did not measure

39 Discussion Limitations Advantages and Disadvantages to Methods Used Comparison to Previous Studies

40 Discussion Advantages and Disadvantages to Methods Used: Root Curvature Muffle Device Software Precision Factors

41 Discussion Advantages and Disadvantages to Methods Used: Root Curvature Muffle Device Ledges Software Precision Factors

42 Advantages and Disadvantages to Methods Used: Root Curvature Discussion Schafer E, Diez C, Hoppe W, Tepel J. Roentgenographic Investigation of Frequency and Degree of Canal Curvatures in Human Permanent Teeth. J Endod. 2002;28(3)

43 Advantages and Disadvantages to Methods Used: Root Curvature Discussion Berbert A, Nishiyama CK. Curvaturas radiculares, Uma nova metodologia para mensuracao e localizacao. Rev Gaucha Odontol 1994:42:356-8.

44 Advantages and Disadvantages to Methods Used: Root Curvature Schafer E, Diez C, Hoppe W, Tepel J. Roentgenographic Investigation of Frequency and Degree of Canal Curvatures in Human Permanent Teeth. J Endod. 2002;28(3) Discussion

45 Discussion Advantages and Disadvantages to Methods Used: Root Curvature Schafer E, Diez C, Hoppe W, Tepel J. Roentgenographic Investigation of Frequency and Degree of Canal Curvatures in Human Permanent Teeth. J Endod. 2002;28(3)

46 Advantages and Disadvantages to Methods Used: Root Curvature Discussion Cunningham CJ, Senia ES. A three-dimensional study of canal curvatures in the mesial roots of mandibular molars. J Endod Jun;18(6):

47 Advantages and Disadvantages to Methods Used: Root Curvature Discussion

48 Discussion Advantages and Disadvantages to Methods Used: Root Curvature Muffle Device Ledges Software Precision Factors

49 Advantages and Disadvantages to Methods Used: Muffle Device Use Endo Cube Use CT (micro) Discussion

50 Discussion Advantages and Disadvantages to Methods Used: Root Curvature Muffle Device Software Precision Factors

51 Discussion Advantages and Disadvantages to Methods Used: Root Curvature Muffle Device Software Precision Factors

52 Discussion Advantages and Disadvantages to Methods Used: Software First use of DesignCAD 3000 for this purpose Advantages: archive-able, reproducible

53 Discussion Advantages and Disadvantages to Methods Used: Root Curvature Muffle Device Software Precision Factors

54 Discussion Advantages and Disadvantages to Methods Used: Precision Factors Quality (resolution, focus, contrast) Angle Magnification

55 Discussion Limitations Advantages and Disadvatages to Methods Used Comparison to Previous Studies

56 Discussion Comparison of Results to Previous Studies: Kessler and Peters 1983 Berutti 1992 Isom 1995 Pilo 1988

57 Discussion Comparison of Results to Previous Studies: Kessler and Peters 1983 Berutti 1992 Isom 1995 Pilo 1988

58 Discussion Comparison of Results to Previous Studies: Kessler and Peters 1983 They had no perforations with size 2 or 3 GGbs This agreed with our results They had thinner walls near the bifurcation Not analyzed in our study, but 5/6 perforations were near the furcation They found the thinnest sections 2.8 mm apical to furcation We found highest perforation rate 5 mm apical to furcation

59 Discussion Comparison of Results to Previous Studies: Kessler and Peters 1983 Berutti 1992 Isom 1995 Pilo 1988

60 Discussion Comparison of Results to Previous Studies: Berutti 1992 Berutti only studied anatomy no instrumentation He found the thinnest dentin 1.5 mm apical to furcation, only 1.2-to 1.3 mm thick He concluded this was the level at highest risk for perforation We did not look at 1.5 mm level Our perforations took place 5/6 at 5 mm apical to furcation, and none at 3 mm, 1 at 7 mm apical to the furcation

61 Discussion Comparison of Results to Previous Studies: Kessler and Peters 1983 Berutti 1992 Isom 1995 Pilo 1988

62 Discussion Comparison of Results to Previous Studies: Isom 1995 Isom also had no perforations with size 2 or 3 GGbs This agrees with our results and the results of Kessler

63 Discussion Comparison of Results to Previous Studies: Kessler and Peters 1983 Berutti 1992 Isom 1995 Pilo 1988

64 Discussion Comparison of Results to Previous Studies: Pilo 1988 Pilo studied premolars Pilo used sequence of k-files to size 40, we filed to size 25. Pilo showed a statistical difference with regard to size 2 GGb vs. 4 GGb with regard to RDT Our study showed statistical difference of size 5 GGb to other sizes with regard to RDT. Sizes 2-4 were not different with regard to RDT Our study results showed half the perforations with size 4 GGb, the other half with size 5 GGb

65 Discussion All direct comparisons must be made with caution due to the differences in study design and methods

66 Conclusions 1) The sizes 2 and 3 Gates Glidden burs, used in a step-down fashion to a level 7 mm apical to the furcation in lower molars, appear to be safe within the confines of this study. These sizes had no perforations in our study, which agrees with previous studies.

67 Conclusions 2) A size 5 Gates Glidden bur should not be used apical to the furcation in the mesial root of a human mandibular molar.

68 Conclusions 3) The size 4 Gates Glidden should rarely, if ever be used apical to the furcation in the mesial root of a human mandibular molar. If used, it should not be advanced > 3 mm apical to the furcation.

69 Conclusions 4) Due to the wide variability of root anatomy characteristics and interactions involved, each tooth should be evaluated separately prior to treatment.

70 Conclusions 5) The clinician should use caution when stepping-down in roots with pre-operative dentin/cementum thicknesses less than 1 mm near the Danger Zone. Other interactions of root anatomy characteristics and instrument diameter should be considered when stepping-down with Gates Glidden burs.

71 QUESTIONS?

72 Final Thesis Defense Examination Anthony L. Horalek, DDS June 12, 2002