Three-dimensional Analysis of Root Canal Geometry by High-resolution Computed Tomography

Abstract

A detailed understanding of the complexity of root canal systems is imperative to ensure successful root canal preparation. The aim of this study was to evaluate the potential and accuracy of a three-dimensional, non-destructive technique for detailing root canal geometry by means of high-resolution tomography. The anatomy of root canals in 12 extracted human maxillary molars was analyzed by means of a micro-computed tomography scanner (μCT, cubic resolution 34 μm). A special mounting device facilitated repeated precise repositioning of the teeth in the μCT. Surface areas and volumes of each canal were calculated by triangulation, and means were determined. Model-independent methods were used to evaluate the canals' diameters and configuration. The calculated and measured volumes and the areas of artificial root canals, produced by the drilling of precision holes into dentin disks, were well-correlated. Semi-automated repositioning of specimens resulted in near-perfect matching (< 1 voxel) when outer canal contours were assessed. Root canal geometry was accurately assessed by this innovative technique; therefore, variables and indices presented may serve as a basis for further analyses of root canal anatomy in experimental endodontology.

Keywords

micro-computed tomography root canal anatomy metrical analysis.

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References

Alyassin AM , Lancaster JL , Downs JH , Fox PT (1994). Evaluation of new algorithms for the interactive measurement at surface area and volume. Med Phys 19:419-432.

Baumann MA , Doll GM ( 1997). Spatial reproduction of the root canal system by magnetic resonance microscopy. J Endod 23:49-51.

Berutti E. (1993). Computerized analysis of the instrumentation of the root canal system. J Endod 19:236-238.

Bjørndal L. , Carlsen 0 , Thuesen G. , Darvann T. , Kreiborg S. (1999). External and internal macromorphology in 3D-reconstructed maxillary molars using computerized X-ray microtomography. Int Endod J 32:3-9.

Blaskovic-Subat V. , Smojver B. , Maricic B. , Sutalo J. (1995). A computerized method for the evaluation of root canal morphology. Int Endod J 28:290-296.

Davis GR , Wong FS ( 1996). X-ray microtomogaphy of bone and teeth. Physiol Meas 17:121-146.

Dowker SE , Davis GR , Elliott JC (1997). X-ray microtomography: nondestructive three-dimensional imaging for in vitro endodontic studies. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 83:510-516.

Elliott JC , Dover SD (1984). Three-dimensional distribution of mineral in bone at a resolution of 15 micron determined by x-ray microtomography. Metab Bone Dis Relat Res 5:219-221.

Engelke K. , Karolczak M. , Lutz A. , Seibert U. , Schaller S. , Kalender W. (1999). Micro-CT technology and application for assessing bone structure. Radiologie 39:203-212.

10.

Gambill JM , Alder M. , del Rio CE (1996). Comparison of nickel-titanium and stainless steel hand-file instrumentation using computed tomography. J Endod 22:369-375.

11.

Gani 0 , Visvisian C. (1999). Apical canal diameter in the first upper molar at various ages. J Endod 25:689-691.

12.

Hess W. ( 1921). Formation of root canals in human teeth. J Natl Dent Assoc 3:704-725.

13.

Hildebrand T. , Rüegsegger P. (1997a). Quantification of bone micro architecture with the structure model index. Computer Meth Biomech Biomed Eng 1:15-23.

14.

Hildebrand T. , Rüegsegger P. (1997b). A new method for the model independent assessment of thickness in three-dimensional images. J Microscop 185:67-75.

15.

Kerekes K. , Tronstad L. (1977). Morphometric observations on the root canals of human molars. J Endod 3:114-118.

16.

Lancaster JL , Eberly D. , Alyassin A. , Downs JH 3rd , Fox PT (1992). A geometric model for measurement of surface distance, surface area, and volume from tomographic images. Med Phys 19:419-431.

17.

Lorensen WE , Cline HE (1987). Marching Cubes: a high resolution 3D surface construction algorithm. Computer Graph 21:163-169.

18.

Meyer W. (1955). Die Darstellung der Wurzelkanale. Zahnärztl Rundsch 64:532-534.

19.

Morton EJ , Webb S. , Bateman JE , Clarke LJ , Shelton CG (1990). Three-dimensional x-ray microtomography for medical and biological applications. Phys Med Biol 35:805-820.

20.

Nielsen RB , Alyassin AM , Peters DD , Cames DL , Lancaster J. (1995). Microcomputed tomography: an advanced system for detailed endodontic research. J Endod 21:561-568.

21.

Pruett JP , Clement DJ , Carnes DL Jr (1997). Cyclic fatigue testing of nickel-titanium endodontic instruments. J Endod 23:77-85.

22.

Rhodes JS , Pitt Ford TR , Lynch JA , Liepins PJ , Curtis RV (1999). Micro-computed tomograpy: a new tool for experimental endodontology. Int Endod J 32:165-170.

23.

Rüegsegger P. , Koller B. , Müller R. (1996). A microtomographic system for the nondestructive evaluation of bone architecture. Calcif Tissue Int 58:24-29.

24.

Stein TJ , Corcoran JF , Zillich RM (1990). Influence of the major and minor foramen diameters on apical electronic probe measurements. J Endod 16:520-522.

25.

Tachibana H. , Matsumoto K. (1990). Applicability of X-ray computerized tomography in endodontics. Endod Dent Traumatol 6:16-20.

26.

Thompson SA , al- Omari AO , Dummer PM (1995). Assessing the shape of root canals: an in vitro method using microradiography. Int Endod J 28:61-67.

27.

Youssefzadeh S. , Gahleitner A. , Dorffner R. , Bernhart T. , Kainberger FM (1999). Dental vertical root fractures: value of CT in detection. Radiology 210:545-549.