Comparative micro-computed tomographic evaluation of two carrier-based obturation systems.

OBJECTIVES: The aim of the study was to measure the percentage of volume of voids and gaps in the apical third of root canals obturated with two techniques using micro-computed tomography. MATERIALS AND METHODS: Fifty-four single-rooted teeth were collected and root canal-prepared. The roots were randomly allocated into two groups; each group was obturated by using thermoplasticized technique with a different material (gutta-percha and Topseal for Thermafil, Resilon and RealSeal for RealSeal 1). Roots were then scanned, and volume measurements for voids and gaps in the obturated roots were carried out using specialized CT software. Percentage of gaps and voids was calculated. RESULTS: The present study showed that none of the root canal-filled teeth was gap free. Student t test was conducted. No significant difference was found between Thermafil and RealSeal 1 concerning percentage of voids in the apical third (P > 0.05). Both materials showed statistically significant difference between the levels where 1 mm showed the highest volume of voids (P < 0.05). CONCLUSIONS: Both carrier-based techniques allowed a good sealing ability in root canals but none of the materials was gap free. Statistically significant difference between the levels was found and 1 mm showed the highest volume of voids. CLINICAL RELEVANCE: This study shows the efficiency of carrier-based obturation systems in filling root canals hermetically. It compares new adhesive endodontic materials with the traditional gold standard gutta-percha. Results show the good sealing ability of both techniques making them appropriate to use in daily endodontic obturations.

Influence of apical taper on the quality of thermoplasticized root fillings assessed by micro-computed tomography.

The objective of this study is to study the influence of final canal taper on the sealing ability of Real Seal 1 by using micro-computed tomography (micro-CT). Fifty-four single-rooted teeth were instrumented to apical size of 40 taper 4, 6, and 8. The teeth were divided into three groups. All teeth were filled with Real Seal 1 (RS1; SybronEndo, Orange, CA, USA). Roots were then scanned with mico-CT, and volume measurements of voids in the apical third and in sections at 1, 3, and 5 mm from the apex were calculated in the obturated roots using specialized CT software. Measurements were analyzed statistically by using ANOVA followed by Bonferroni multiple comparison correction. Data analysis showed that 0.08% and 0.06% apical tapered RS1 obturations provided better results than 0.04% tapered samples. The present study showed that none of the root canals filled teeth were gap free. Mean percentages of voids were significantly higher with Real Seal 1 taper 0.04% (P = 0.05).There was no significant difference with 0.06 and 0.08 final taper. For Real Seal 1 technique 0.06 and 0.08 tapered preparations seem to be more optimal. At 1 mm, final taper 0.08 showed less voids and gaps than the two other final tapers. In our daily practice, enlarging the apical third (last 3 mm) of root canals to an 8% taper is necessary to achieve a better sealing ability and thus long-term success for our root canal obturations.

Clinical evaluation of the Carisolv chemomechanical caries removal technique according to the site/stage concept, a revised caries classification system.

The objective of the present study was to assess the efficiency and benefit of a chemomechanical system for carious dentin removal, Carisolv, in general practice. A revised caries classification, the site/stage concept, was used to describe the clinical situations of all carious lesions treated. The study was performed by 12 investigators, and 120 carious lesions were treated with Carisolv. Sixty percent of the cases were treated without anaesthesia, and we found a significant correlation between chemomechanical treatment without anaesthesia and absence of pain ( P=0.01). In 78.3% of the cases, carious dentin was totally removed with Carisolv, and in 21.7%, the dentin treatment was completed by drilling. In cases performed with Carisolv alone, the time required to remove carious dentin was 11.1+/-9.51 min (mean+/-SD). Treatment time was equivalent for all sites and increased significantly with each successive stage of lesion progression ( P<0.001). In 82.5% of cases, the clinicians were satisfied with Carisolv, and in 99.2%, so were the patients. We conclude that, using clinical examination methods, Carisolv seems to remove carious dentin at all sites and stages of carious lesions but must be made more efficient for use in general practice.

Curved molar root canal preparations using Hero 642 rotary nickel-titanium instruments.

AIM: The Bramante method was used to study how the natural curvature of root canals was modified when using the Hero 642 nickel-titanium rotary system. METHODOLOGY: Twenty-four canals were selected in freshly extracted human mandibular molars. Every root canal had an angle of curvature greater than 20 degrees. Roots were embedded in clear casting resin using a plaster mould. Cross-sectional cuts were made in the apical, middle and coronal thirds of each root. A first group (control) of 12 curved root canals was prepared using stainless steel hand instruments and the step-back technique. A second group of 12 curved root canals was instrumented using the Hero sequence according to the manufacturer's instructions. For each sectioning level, the amount of dentine removed, the change of shape factor and the canal centre displacement were calculated with the aid of a digital image analysis system. The results were subjected to the Mann-Whitney U-test. RESULTS: No significant difference occurred in the amount of dentine removed, change of shape factor or canal centre displacement in the coronal and middle thirds of the curved canals. In the apical third, transportation was significantly higher (P=0.0171) with stainless steel hand instruments than with the Hero system. CONCLUSIONS: The original canal shape was maintained better in the apical third of curved canals when using the Hero system in a crown-down technique when compared to a hand preparation technique with stainless steel instruments.

The removal of the smear layer using the Quantec system. A study using the scanning electron microscope.

AIM: The aim of this study was to determine the ability of the Quantec Series 2000 rotary nickel-titanium endodontic system to remove dentinal debris and smear layer produced during canal preparation. METHODOLOGY: A first group (control) of 12 curved root canals was prepared using conventional manual instruments and the step-back technique. A second group of 12 curved root canals was instrumented using the complete Quantec sequence according to the manufacturer's instructions. In both groups, irrigation was performed using a 3% NaOCl solution. The canal walls were observed under a scanning electron microscope and the coronal, middle and apical thirds of each canal photographed at a magnification of 500. The views were divided into 10 subareas by overlaying a grid, and the absence or presence of a smear layer was rated and scored on three appearances using the scale described by Ciucchi et al. (1989). RESULTS: The scores were higher (i.e. less debris was present) in the middle third (P < 0.0001) and in the apical third (P < 0.0001) of canals prepared with the Quantec system when compared with those prepared with K-files. Nevertheless, in canals prepared with Quantec instruments, the scores were significantly higher in the coronal third compared with the apical third (P < 0.005). CONCLUSIONS: The Quantec rotary system produced cleaner canal walls than conventional manual instrumentation, particularly in the middle and apical thirds. This finding may imply that stresses applied to the cutting regions of Quantec instruments by accumulation and compression of the smear layer are minimized.

[Comparative study of different imbedding materials for light histology of decalcified human teeth]. / Etude comparative de différents matériaux d'inclusion en vue de l'étude en histologie photonique des dents humaines decalcifiées.

Four embedding media were compared: paraffin, the mixing "paraplast-piccolyte", Technovit 7100, and JB 4. Each material embedding technic is described. Comparison criteria are: easiness in the technic and method, cutting and trimming qualities, staining, anatomy connections conservation. Results are compacted in a diagram and illustrated by microphotographs. Methacrylate resins, and particularly JB 4, gave us best results.