Publications by authors named "Calas P"

Fixation of the graft during anterior cruciate ligament reconstruction surgery has been the subject of numerous technical innovations but still remains a challenge. This article describes a novel technique of graft fixation for hamstring tendon reconstruction: the Cage For One system (Sacimex, Aix-en-Provence, France). The technique uses only the semitendinosus tendon, which is looped to create a 4-strand graft.

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Samples were taken under strictly anaerobic conditions from the root canals of 22 patients having a tooth in which necrotic pulp was associated with an inflammatory peri-apical lesion an optical periodontitis. In the majority of cases (85%), these lesions were chronic and the pulp chamber was closed. One hundred and two strains were isolated, 71.

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New alpha,omega-semifluorinated dithiols HS-(CH2)11-(CF2)n-(CH2)11-SH, called DTn, and corresponding dithioacetate molecules CH3COS-(CH2)11-(CF2)n-(CH2)11-SCOCH3, called DTAn ( n = 4, 6, 8), were synthesized and used to create self-assembled monolayers (SAMs) on both untreated copper surfaces and electrochemically reduced ones. The aim of this study is to assess the organization of the resulting SAMs, particularly the effect of the presence of two perhydrogenated segments surrounding the perfluorinated one, and the ability of these difunctional molecules to bind copper substrates by only one end per molecule. In each case, the organization of the SAM is rather poor and only DTA8 molecules seem to adopt an upright position on reduced copper.

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Aims: This study set out to evaluate the prevalence of iatrogenic events during preclinical teaching of endodontics, comparing manual stainless steel versus nickel-titanium (Ni-Ti) rotary techniques for shaping natural root canals.

Method: Two groups of 13 inexperienced dental students were randomly made up and asked to shape 104 canals in natural teeth. Group R used Ni-Ti rotary files for shaping while Group M used a sequence of five manual stainless steel files.

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Calcium hydroxide placed as a temporary dressing in the root canal helps sterilize infected canals. Hycal and Roeko calcium hydroxide points are two delayed-action medications containing Ca(OH)2 recommended for root canal treatment. The purpose of this study was to test their bactericidal activity in comparison with that of C-PMCP on Streptococcus sanguins strain NCTC 7823.

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The aim of this study was to compare hydroxyl ions diffusion from various calcium hydroxide forms: Hycal (1), Roeko points (2) and aqueous suspension placed in the pulpar chamber (3) or in the root canal (4). These experiments were conducted with bovine incisors in order to obtain quantitative evaluation. 540 lateral cavities, deep and superficial, were created in root dentin to measure the hydroxyl ions diffusion with a color indicator, the Blue epsilon With Hycal and aqueous suspension the diffusion of the OH- is obtained in the superficial cavities situated in the coronal part at 14 days (1 = 72%; 3 = 44%; 4 = 100%, (n=18)).

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The warm vertical gutta-percha compaction technique requires canals to be sufficiently flared to allow the tip of the plugger to penetrate to the apical third. The aim of the present study was to determine whether apical preparation or finishing instruments could be used to improve the penetration depth of pluggers. Single-root canals (48) were prepared using different rotary Ni-Ti instruments: M File System (I), ProTaper (II), HEROShaper (III), and EndoK3 (IV).

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A retrospective study was carried out looking at the files of 481 patients who were seen for their first consultation at a university hospital dental school clinic. Their needs for conservative treatment were evaluated and the data from their files were analysed, including the following elements: demography, general health status, the expressed reason for the consultation, and the initially planned treatment. The descriptive analysis reveals a relatively young population group with an average age of 43.

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The behavior of nickel-titanium instruments depends largely on the cross-section of the working part. The effect of pitch length was evaluated using two instruments with the same cross-section (triple helix; 0.6% taper).

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In the presence of anterior unitary tooth loss, the therapeutical arsenal of the practitioner remains the implant solution. But, at the young patients who have not completed their growth, it's necessary to pass by a transitional stage. The bonded bridges reinforced by a polyethylene fibbers splint such as Ribbond THM constitute an alternative of choice to solve the aesthetic damage in the short and medium term while waiting for the prosthesis with implant.

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Unlabelled: The general configuration of replaced knee is difficult to anticipate because of the large number of geometrical parameters related to morphology, prosthetic implants and pre-operative choices (such as ligament release). This article features the studies achieved in order to create a decision aiding computer tool dedicated to total knee prosthesis. METHOD AND MODEL: We have built a geometrical modelling of the physiological knee and prosthesis elements association.

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In order to set up a disinfection protocol, the tip of the optical fibre of an Nd-YAP laser, λ=1.34 μm, was contaminated in vitro with: Mycobacterium smegmatis (CIP 7326), Candida albicans (ATCC 2091), Bacillus stearothermophilus (ATCC 7953) or Streptococcus sanguis (ATCC 10556). It was then treated with various biocidal solutions, Septinol(®) V, glutaraldehyde 2%, ethanol 95° and NaOCl 6%, using one of two protocols: 10 s of contact, or 5 s of contact followed by 5 s of wiping.

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The bactericidal activity of a pulsed fibre-optic Nd-YAP laser on various strains of oral bacteria: Prevotella nigrescens, Streptococcus sanguis, Actinomyces viscosus (i), Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans and Peptostreptococcus micros (i) was evaluated. A 200-μm optical fibre was placed in Eppendorf tubes containing the different bacterial suspensions. At an energy of 170 mJ/30 Hz, 351 pulses of 150 μs were sufficient to kill the most resistant bacteria (i).

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Blocks of bovine incisor dentin, on the root canal surface of which a smear layer had been formed, were inoculated in vitro with two strains of Prevotella nigrescens, a wild sampled strain and a reference one (NCTC 9336). Half the blocks were pretreated with irrigating solutions: 6% citric acid for 5 min + 6.25% sodium hypochlorite for 10 min.

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Effect of dentin treatment on in vitro root tubule bacterial invasion.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod

October 1996

In light of the in vitro S. sanguis bacterial migration observed deep into root dentin, an in vitro system was developed to determine the viability of these bacteria at the end of migration. Also of interest is whether the smear layer formed during root canal instrumentation modifies migration into root dentinal tubules.

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The adhesion of a strain of Streptococcus sanguis (NCTC 7863) to the root canal dentin of bovine incisors was evaluated. Samples (104) were prepared and smear layer was created on the root canal surface with a tungsten carbide bur. The samples were divided into four groups, one of them serving as a control sample and the other three each receiving a different treatment: 6% citric acid for 2 min (group 3), 6% citric acid for 2 min + 6.

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During canal preparation, the repeated passage of instruments provokes the formation of smear on the surface of the dentin. It is advisable to eliminate that, so as to increase antisepsis and filling impermeability. This is obtained by means of an irrigation, using a chelate compound of 6% citric acid for 60 seconds, at the end of the preparation.

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The purpose of this study was to assess in vitro migration of the following three bacterial species into dentinal tubules: Streptococcus sanguis, Actinomyces naeslundii and Prevotella intermedia. Twenty-seven bovine incisors were randomly divided into three groups. Only the root dentin was used for the experiment.

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The persistent presence of bacteria in the root canal system often leads to the failure of treatment. The aim of this study was to study the in vitro penetration of root dentinal tubules by bacteria. Bovine dentin was inoculated with a strain of Streptococcus sanguis, NCTC 7863; samples were taken at 10, 20, and 28 days, and bacterial penetration of the tubules was demonstrated using two techniques, scanning electron microscopy and light microscopy after Brown and Brenn staining.

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240 permanent teeth from 8 different dogs aged 1, 3, 8, 10, 15 years, were used for an anatomic study. The teeth were cleaned, their root canal system was stained with dye, then the teeth were decalcified and cleared to determine the root canal anatomy. The apical root canal anatomy in dogs can be described as a "sprinkler-rose" anatomy: at the tip of the pulpal canal, the canal is divided in numerous narrow channels radiating peripherally through the dentin and the cementum and ending in numerous apical foramina on the cementum surface.

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The scanning electron microscope has multiple applications in the research of endodontics, but there are not standard methods for the evaluation of the results. The use of the computerized processing and analysing systems for the images reduces the sources of error due to the subjectivity of the operator. This first part, after the introduction of the principles of processing and analysis, puts in view two methods of computerized analysis used in the study of the films of dentinal walls in the scanning electron microscope.

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The continuous high volume of irrigating solution delivered by the ultrasonic system facilitates the root canal debridement. An excellent cleaning of dentin wall is obtained even on surfaces unreached by the mechanical instrumentation. In order to obtain an efficacious preparation, the use of ultrasonic files were combined with instrumentation.

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