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Materials and Methods• Study Design• Specimen Preparation• Canal Instrumentation• Photos and Computer Imaging• Manipulation of Images with
Software Program• Data Collection and Statistical
Analysis
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
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 distalRDT
Materials and Methods• Data Collection and Statistical
Analysis• Due to the small number of
perforations (yes, no), they were described, but not statistically analyzed
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)
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)
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)
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)
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)
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)
Results• Outcome: Post-operative distal dentin
thickness• Two main effects (Table 9)• Two, two-way interactions (Only one is
illustrated, (Fig. 7)
Results• Outcome: Post-operative distal dentin
thickness• Two main effects (Table 9)• Two, two-way interactions (Only one is
illustrated, (Fig. 7)
Results• Outcome: Post-operative distal dentin
thickness• Two main effects (Table 9)• Two, two-way interactions (Only one is
illustrated, (Fig. 7)
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.)
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
Results• Outcome: mesial dentin thickness
• No main effects• Two, two-way interactions
• (Curvature * Canal) (Fig. 8)• (Pre-op dentin thick*Gates) (Fig. 9)
Results• Outcome: mesial dentin thickness
• No main effects• Two, two-way interactions
• (Curvature * Canal) (Fig. 8)• (Pre-op dentin thick*Gates) (Fig. 9)
Results• Outcome: mesial dentin thickness
• No main effects• Two, two-way interactions
• (Curvature * Canal) (Fig. 8)• (Pre-op dentin thick*Gates)
(Fig. 9)
Results• Outcome: mesial dentin thickness
• No main effects• Two, two-way interactions
• (Curvature * Canal) (Fig. 8)• (Pre-op dentin thick*Gates) (Fig. 9)
Results• Outcome: mesial dentin
thickness• No main effects• Two, two-way interactions
• (Curvature * Canal) (Fig. 8)• (Pre-op dentin thick*Gates)
(Fig. 9)
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
Results• Outcome: perforations
Results• Outcome: perforations
Discussion• Limitations• Advantages and Disadvantages to
Methods Used• Comparison to Previous Studies
Discussion• Limitations• Advantages and Disadvantages to
Methods Used• Comparison to Previous Studies
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
Discussion• Limitations• Advantages and Disadvantages to
Methods Used• Comparison to Previous Studies
Discussion• Advantages and Disadvantages to
Methods Used:• Root Curvature• Muffle Device• Software • Precision Factors
Discussion• Advantages and Disadvantages to
Methods Used:• Root Curvature• Muffle Device• Ledges• Software • Precision Factors
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)211-16.
Discussion• Advantages and
Disadvantages to Methods Used:• Root Curvature
Berbert A, Nishiyama CK.Curvaturas radiculares,Uma nova metodologia para mensuracao elocalizacao. Rev Gaucha Odontol 1994:42:356-8.
Discussion• Advantages and
Disadvantages to Methods Used:• Root Curvature
Schafer E, Diez C, Hoppe W, Tepel J.RoentgenographicInvestigation of Frequency and Degree of Canal Curvatures in Human Permanent Teeth. J Endod. 2002;28(3)211-16.
Discussion• Advantages and
Disadvantages to Methods Used:• Root Curvature
Schafer E, Diez C, Hoppe W, Tepel J.RoentgenographicInvestigation of Frequency and Degree of Canal Curvatures in Human Permanent Teeth. J Endod. 2002;28(3)211-16.
Discussion• Advantages and
Disadvantages to Methods Used:• Root Curvature
Cunningham CJ, Senia ES. A three-dimensional study of canal curvatures in themesial roots of mandibularmolars. J Endod. 1992 Jun;18(6):294-300.
Discussion• Advantages and
Disadvantages to Methods Used:• Root Curvature
Discussion• Advantages and Disadvantages to
Methods Used:• Root Curvature• Muffle Device• Ledges• Software • Precision Factors
Discussion• Advantages and
Disadvantages to Methods Used:• Muffle Device
• Use Endo Cube• Use CT (micro)
Discussion• Advantages and Disadvantages to
Methods Used:• Root Curvature• Muffle Device• Software • Precision Factors
Discussion• Advantages and Disadvantages to
Methods Used:• Root Curvature• Muffle Device• Software • Precision Factors
Discussion• Advantages and Disadvantages to
Methods Used:• Software
• First use of DesignCAD 3000 for this purpose
• Advantages: archive-able, reproducible
Discussion• Advantages and Disadvantages to
Methods Used:• Root Curvature• Muffle Device• Software • Precision Factors
Discussion• Advantages and Disadvantages to
Methods Used:• Precision Factors
• Quality (resolution, focus, contrast)
• Angle• Magnification
Discussion• Limitations• Advantages and Disadvatages to
Methods Used• Comparison to Previous Studies
Discussion• Comparison of Results to Previous
Studies:• Kessler and Peters 1983• Berutti 1992• Isom 1995• Pilo 1988
Discussion• Comparison of Results to Previous
Studies:• Kessler and Peters 1983• Berutti 1992• Isom 1995• Pilo 1988
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
Discussion• Comparison of Results to Previous
Studies:• Kessler and Peters 1983• Berutti 1992• Isom 1995• Pilo 1988
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
Discussion• Comparison of Results to Previous
Studies:• Kessler and Peters 1983• Berutti 1992• Isom 1995• Pilo 1988
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
Discussion• Comparison of Results to Previous
Studies:• Kessler and Peters 1983• Berutti 1992• Isom 1995• Pilo 1988
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
Discussion• All direct comparisons must be made
with caution due to the differences in study design and methods
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.
Conclusions• 2) A size 5 Gates Glidden bur should
not be used apical to the furcation in the mesial root of a humanmandibular molar.
Conclusions• 3) The size 4 Gates Glidden should
rarely, if ever be used apical to thefurcation in the mesial root of a human mandibular molar. If used, it should not be advanced > 3 mm apical to the furcation.
Conclusions• 4) Due to the wide variability of root
anatomy characteristics and interactions involved, each tooth should be evaluated separately prior to treatment.
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.
QUESTIONS?
Final Thesis Defense Examination
Anthony L. Horalek, DDSJune 12, 2002
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