Article: Micro-Computerized Tomographic Analysis of Radicular and Canal Morphology of Premolars with Long Oval Canals. Source: OOOOE, August 2008.

Objective: Measure root and canal diameters and ratios, canal tapers and wall thickness.

M&M: Thirty human premolars with single canals were selected. Specimens were scanned using Micro CT and cross-sections analyzed at the following levels: 1,2,3,4,5,7,9,11 and 13mm from the radiologic apex.

Take aways:
1) At all levels, the BL (bucccolingual) diameter of the canal was greater than the MD (mesiodistal) diameter. This means that the canal diameter the dentist typically sees on the x-ray (MD view) was always smaller than the size of the canal they don’t see (BL view). For example, the data shows that at 1mm from the apex, the canal diameter as seen by the dentist averaged 0.32mm. However, in the view they don’t see, the canal diameter was much larger, 0.45mm. If one prepares the canal with a size #35 instrument the canal would be under prepared at the 1mm level because in reality one would have to go two sizes larger to a size #45 to properly clean the canal, 3-dimensionally.

2) The canal’s taper, in the BL dimension is much greater than the MD dimension. So the taper you don’t see is much larger than the taper you do see. Measurements taken in the MD dimension showed tapers ranging from (0.03 to 0.06 mm/mm) but in the BL dimension they were significantly greater (0.13 to 0.27mm/mm)! If one prepares the canal to a common taper (let’s say .04 taper) it more often than not under prepared in BOTH dimensions, particularly in the BL dimension (.04 vs. 0.18 average).

This puts serious doubt as to the efficacy of tapered preparations in general. Can one expect to effectively clean canals, with 0.04 or 0.06 tapered instruments, when the canal’s dimensions (at a minimum) are 0.45mm diameter with a 0.13 taper?

Article: Micro-computerized tomographic analysis of radicular and canal morphology of premolars with long oval canals. OOOOE, August 2008.

Efficiency of EndoVac System to Remove Artificially Placed Dentin Debris

H.S. SONG, Y.J. KIM, Y.B. CHO, and C.U. HONG, Dankook University, Cheonan, Chungnam, South Korea

Objectives: The purpose of this study was to evaluate the effectiveness of Endovac system to remove artificially placed dentin debris.

Methods: Twenty extracted single rooted permanent teeth were allocated randomly into two groups. The pulp chambers were accessed and the canals were prepared by #40,. 06 taper Profile system. After canal preparation, teeth were split longitudinally into two halves. Three standard saucer-shaped depression of 0.3 mm in diameter and 0.5 mm in depth were cut in the root canal at 2, 4, and 6mm from the apex to simulate uninstrumented canal irregularities. Each depression were filled with dentin debris mixed with 5.25% NaOCl to simulate a situation when dentin debris accumulates in the uninstrumented canal extensions. Two halves of each tooth were reassembled using wire and sticky wax. In group 1, the canal was irrigated by using the Endovac system, which uses negative pressure to deliver irrigating solutions to working length. In the other group, canal was irrigated with 27 gauge irrigating needle. All teeth were irrigated with sodium hypochlorite and EDTA according for a predetermined amount of time. The amount of remaining dentin debris in the depressions were evaluated by a microscope and SEM.

Results: Both irrigation methods reduced the debris score significantly. The debris score was stastistically lower after the Enodovac system than after conventional irrigation.

Conclusions: This study showed better debridement by using the Endovac system compared with conventional irrigation.

Evaluation of New System for Root Canal Irrigation to Conventional: An Ex Vivo Study

Dr. Prashanth, Dr. Vasundhara Shivanna. Dept. Of Conservative Dentistry & Endodontics, College Of Dental Sciences, Davangere.

AIMS AND OBJECTIVES OF STUDY:
To compare the efficacy of the LightSpeedLSX^TM with and without the EndoVac^TM irrigation System to debride root canals at 1mm and 3mm from working length.

MATERIAL AND METHODS:
22 freshly extracted intact non carious human mandibular premolars with complete root formation were collected for the study from Department of Oral & maxillofacial surgery.  All teeth were instrumented with LightSpeedLSX and split into 3 groups: No irrigation, Conventional irrigation with NaOCL, and Irrigation with EndoVac (NaOCL).

Six micron serial histologic sections are made and stained with hematoxylin and eosin. Sections of each glass slide are compared using light microscope at 100X magnification. The amount of debris left in canals are quantified as percentage of canal lumen area. The data was statistically analyzed to compare percentage of debris and efficacy of irrigation techniques.

RESULTS: Mean % “Clean” – 100% = Completely Free of Debris

	LightSpeedLSX with No Irrigation	LightSpeedLSX with Conventional Irrigation	LightSpeedLSX with EndoVac Irrigation
1 mm from Working Length	70%	94%	99%
3 mm from Working Length	72%	96%	99.5%

The combination of LSX and EndoVac was able to render these canals 99%+ free of debris.  Average instrumentation time with LSX was 6.1 minutes.  EndoVac circulated 24ml through the canal system compared to only 3.4ml with conventional irrigation.