Self-perceived educational needs of junior assistant professors in Conservative Dentistry and Endodontics in France.

INTRODUCTION: Academic dental educators play a major role in training future dentists. They help students to develop medical knowledge and behavioural skills that improve the quality and rigor of their future practice. Therefore, their experience and knowledge are critical to ensure effective learning. However, a French national workshop revealed that most junior assistant professors lack educational skills at the beginning of their career. The aim of this study was to assess educational training needs of junior assistant professors in the Department of Conservative Dentistry and Endodontics. MATERIALS AND METHODS: An electronic survey was sent to junior assistant professors belonging to Departments of Conservative Dentistry and Endodontics within the 16 French dental schools in 2016. This survey was designed to collect data regarding their motivations, teaching expertise and interest in pedagogy. RESULTS: Sixty of the 69 junior educators turned in their answers, which represents a response rate of 87%. About 86.7% of respondents cited their attraction to teaching as one of the main reasons behind their application. The major difficulty encountered by junior faculty was related to course preparation. Only 15% had received educational training despite the fact that 98.3% were convinced of the usefulness of such a training for junior teachers. CONCLUSION: This study identified the motivations and difficulties encountered by junior assistant professors. This collection of educational needs should be considered when planning a national programme for educational training of dental faculty that will promote the acquisition of teaching skills and improve the education of dental students.

Shaping ability of two rotary instruments in simulated canals: stainless steel ENDOflash and nickel-titanium HERO Shaper.

AIM: To compare the shaping ability of two rotary instruments in simulated curved canals: stainless steel ENDOflash Files (KaVo, Biberach, Germany) and the recently introduced nickel-titanium HERO Shaper instruments (Micro-Mega, Besançon, France). METHODOLOGY: Simulated root canals with 35 degree curves in resin blocks were prepared to size 30, .04 taper (HERO Shaper) using a crowndown technique or size 30, .02 taper (ENDOflash) using a rotary motion and a rotation speed of 400 or 250 rpm respectively. In both groups, irrigation was performed with 1 mL distilled water after each instrument size and Glyde (Dentsply Maillefer, Ballaigues, Switzerland) were used. Canals (n = 17 per group) were scanned before, during and after preparation. The assessment of preparation shape was carried out with a computer image analysis program. Material removal was measured at seven points beginning 1 mm from the end-point of the canal. Statistical analysis was performed using Wilcoxon's test and Fisher's exact test (P < 0.05). RESULTS: No instrument fractures, apical blockage or loss of working length (WL) occurred. More zips (10 vs. 4) and more strippings (17 vs. 0) were created with ENDOflash compared with the HERO Shaper. There were significant differences in terms of the amount of resin removed on the inner wall of the curvature obtained with the two instruments (P < 0.0001). On average, HERO Shaper instruments removed material more evenly on the outer and inner wall of the curvature. Considering the different points of measurement, there were significant differences between the two systems both on the inner and outer walls at WL-1, 2, 5 and 6 mm (P < 0.05). The HERO Shaper had a more centred enlargement compared with the ENDOflash. CONCLUSIONS: Stainless steel rotary ENDOflash instruments did not perform as well as HERO Shaper instruments and created an increased risk of root canal transportation. Nickel-titanium rotary HERO Shaper instruments maintained the original curvature significantly better.

Socio-economic and schooling status of dental undergraduates from six French universities.

OBJECTIVES: The aim of this study was to evaluate the socio-economic status of French undergraduate dental students. METHODS: A 46-item questionnaire was completed by the dental students of six universities between 1992 and 1995. Subjects related to family background, housing, schooling, income, expenditure and participation in student life were investigated. RESULTS: A total of 1192 out of 1207 questionnaires were returned. Both genders had equal access to dental training. The average overall cost of the four last years of the dental course was 30,302 French francs and varied greatly between faculties, as did the number of hours spent at the faculty for lectures, tutorials and practicals, and clinical work. Overall, the majority of students came from a well off social background, and had a relatively high quality of life while a small minority received no support from their families. Thirty-four per cent of students had never worked. One third of students smoked and one third regularly consumed medication of some sort. A third did not participate in any sport. Only 25% students bought dental text books and 42% of the students reported using the library regularly. CONCLUSIONS: This study offers an accurate description of the socio-economic status of French dental students that could be used as a reference for comparable studies in other European countries.

Effect of calcium hydroxide form and placement on root dentine pH.

AIM: The aim of this study was to measure variations in dentinal pH following the placement of various forms of calcium hydroxide in either the root canal or the pulp chamber. METHODOLOGY: Extracted single-rooted human teeth were prepared, and the root canals instrumented using a conventional technique. Three cavities were drilled through the root dentine to within 1 mm of the canal wall at the cervical, middle and apical thirds. A total of 125 teeth were randomly divided into five groups; group 1: pure aqueous calcium hydroxide paste (calcium hydroxide/distilled water solution) was placed in the root canal; group 2: the same aqueous calcium hydroxide paste was placed in the pulp chamber; group 3: Hycal, a new form of calcium hydroxide paste, was placed in the pulp chamber; group 4: calcium hydroxide gutta-percha points were placed in the root canal; group 5: control group, wet canal (distilled water) without medication. The access cavities and apical ends were sealed, and the teeth were placed in individual vials containing phosphate-buffered saline, and stored at 37 degrees C. The pH was measured in the dentinal cavities at 8 h and at 1, 2, 3, 7, 14, and 21 days using a calibrated microelectrode. RESULTS: At 8 h and 1, 2, and 3 days, the highest pH values were obtained when the aqueous calcium hydroxide paste was placed in the pulp chamber. At 7 days, the pH had increased in the Hycal group without being significantly different from the aqueous calcium hydroxide paste placed either in the root canal or in the pulp chamber. At 14 days, Hycal( had the highest pH values (pH 10.65); however, at 21 days no significant difference was noted amongst these first three groups. Control group values ranged from 7.88 to 8.60; the pH created by the calcium hydroxide gutta-percha points was lower than for the control group. Whatever the product or placement location, cervical pH was similar to middle pH, and greater than apical. However, there was no significant difference between the three when all groups were combined. Overall, aqueous calcium hydroxide paste placed in the pulp chamber provided the highest pH values during the experiment, except at day 14. The aqueous calcium hydroxide paste placed in the root canal or Hycal had similar values at days 7 and 21. CONCLUSIONS: Under the conditions of this study, an aqueous calcium hydroxide paste placed in the pulp chamber increased dentinal pH more than the other techniques. The pH of dentine is affected by the form of calcium hydroxide used.

Effects of the Nd:YAP laser on coronal restorative materials: implications for endodontic retreatment.

With new wavelengths that allow light transmission by optical fibers, the laser is now often used in endodontics either during treatment or retreatment. The aims of this study were to (i) specify the effects of laser irradiation on restorative materials in terms of topographic effects and (ii) describe different protocols for the first steps of retreatment. The laser used in this study was an optical fiber Nd:YAP (Lokki dt, Vienne, France) with a wavelength of 1.34 microns. Samples of the following restorative materials were prepared: amalgam, composite, permanent and temporary cements, and prosthodontic alloy. The handpiece of the Nd:YAP laser was fixed perpendicular to the surface of the different preparations. All trials were performed with the fiber tip either in contact with or at a distance of 2 mm from the material. The surface effects in all cases were (i) the creation of craters in the center of the lased areas, (ii) a border of fusion material at the edge of the craters, and (iii) cracks or fractures at a distance from the target areas. For the cements, amalgam and composite, the effects included a projection of material from the center to the edge of the lased area and/or the apparent photovolatization of light particles. For all materials the laser induced deeper absorption in the areas of direct contact than when it was held at a distance. This suggests that the fiber should be in contact with the restorative material for lasing in the straight part of the canal when the objective is either to pass through the material or alongside it between material and tooth. If the practitioner cannot determine the direction of the curve of the canal, lasing should be performed at a distance to weaken the material and thus permit more efficient use of an ultrasonic device. Lasing should in all cases be performed under close X-ray monitoring. Provided that sufficient caution is used, the laser may be helpful in removing restorative materials during retreatment.

Rate and growth pattern of radicular apical third tissue apposition in tetracycline-labeled rats.

The aim of this in vivo study was to find a way to conduct qualitative and quantitative evaluations of radicular apical third apposition in rats. Twenty rats were injected intraperitoneally with tetracycline at weight-adjusted doses. Mesio-distal sections of the first mandibular molar regions were prepared. The 60 to 80 microns sections were examined by fluoromicroscopy using reflected light. Visible lines of fluorescence could be seen in the radicular dentin and the cementum. Each line corresponded to one injection. It was possible to define two periods: the first, from day 22 to day 59, corresponded to the immature tooth; the second, from day 59 to day 101, to the mature tooth. During period 1, the mean speed of radicular lengthening by cemental and dentinal apposition was 23.95 microns/24 h. The increase in mesio-distal diameter by cemental apposition was 12.15 microns/24 h. During period 2, the mean speed of radicular lengthening by cemental apposition was 8.23 microns/24 h. It is therefore possible to use this method to conduct quantitative and qualitative evaluations of apical morphogenesis by cemental and dentinal apposition.

[Obturation of curved canals: in vitro study of lateral compaction]. / Obturation des canaux courbes: étude in vitro du compactage latéral.

The instrumentation and filling of teeth with curved canals are always difficult, therefore, the current study indicates solutions to problems encountered while preparing curved canals. The gutta condensation techniques and their ability to seal curved canals are also discussed. This study uses endodontic simulators to show the incidence of protocols and instrumentation on the ability of the lateral condensation technique to fill curved canals. This study, also, evaluate the lateral condensation technique combined with the thermomechanical in filling curved canals.

[A more efficient lateral condensation]. / Pour un compactage latéral plus efficace.

Advantages and inconvenients of the lateral condensation technique are reviewed in this paper. Different ways to gain more efficient lateral condensation are studied: plugger and gutta-percha points selection and adaptation, combination with thermomecanical technique or assistance by ultrasonic or thermal systems. The study of these various methods and combinations leads to the concept of an thermolateral-assisted condensation.

[Fluoromicroscopy]. / La fluoromicroscopie.

The fluorescence is a photoluminescent phenomena consisting in the emission of light under the influence of a light wave excitation. Two types of fluorescence exist: the primary fluorescence (natural) and the secondary (induced by a fluorochrome) The fluoromicroscope is composed of two parts. One of which, unspecific, consists in the classical optical system of the photonic microscopy. The other part, specific, consists in a source of light at a high mercurial pressure and a double filtration system of excitation and pause. There are many applications of this technique. In odontology, it is frequently used for the study of apposition in calcified tissues after their labelling by injection of a fluorochrome.