Biomedical subjects

Marie-France Bertrand

Publications and source records attributed to Marie-France Bertrand.

5 recordsLinked to original sources

PubMed2006

Er:YAG laser cavity preparation and composite resin bonding with a single-component adhesive system: relationship between shear bond strength and microleakage.

BACKGROUND AND OBJECTIVES: The purpose of this study was to assess the performances of a single-component adhesive system when an Er:YAG laser was used to prepare cavities. STUDY DESIGN/MATERIALS AND METHODS: Shear bond strength tests were performed on composite rods bonded with a single-component adhesive system to dentin surfaces prepared using either bur+acid, Er:YAG laser (fluence = 44 J/cm2), or Er:YAG laser+acid. Class V cavities were prepared differently according to the molar surface: buccal surfaces were prepared using a diamond bur, and lingual surfaces using the Er:YAG laser. In group 1, cavity walls were not acid treated after Er:YAG laser preparation. In group 2, only the enamel walls were acid treated. In group 3, all the enamel and dentin walls were acid treated. Microleakage was assessed using a methylene blue dye penetration method. RESULTS: Bond strength values did not differ significantly between the three groups (P = 0.162). Better marginal adaptation was obtained between the composite resin and cavity walls when Er:YAG laser preparation was followed by a total acid etching (P = 0.008). CONCLUSIONS: Our results supported the use of single-component adhesive systems in cavities prepared using Er:YAG laser. The step of acid etching must be maintained for the whole cavity walls in regard of the microleakage values.

Aluminum↗

PubMed2005

Scanning electron microscopy analysis of experimental bone hacking trauma.

The authors report on their macro- and microscopy study of bone lesions made by a sharp force instrument (a single blade knife), and a sharp-blunt instrument classified as a chopping weapon (a hatchet). The aim of this work was to attempt to identify the instrument by analyzing the general class characteristics of the cuts. Each weapon was used on human bones. The results indicate that macroscopic analysis is more problematic. The microscopic analysis assessed that characteristics examined were effective in distinguishing sharp from sharp-blunt injury to the bone. The microscope facilitates analysis unachievable with macroscopic methods, some three-dimensional characteristics not visible to the naked eye being clearly defined with its use. Emphasis has been placed on the value of SEM as an anthropologist's tool in bone lesion injuries.

Femur↗

PubMed2004

Scanning electron microscopic evaluation of resin-dentin interface after Er:YAG laser preparation.

BACKGROUND AND OBJECTIVES: The aim of this study was to observe the morphological characteristics of dentin-resin interfaces when a composite resin was bonded to Er:YAG laser irradiated dentin. STUDY DESIGN/MATERIALS AND METHODS: Human dentin surfaces were divided into three equal areas. One third was prepared using a carbide bur and etched with phosphoric acid, the second third was conditioned using an Er:YAG laser, the third one was irradiated and etched. A hybrid composite resin was bonded on dentin surfaces using a single-component adhesive system. Longitudinal sections were exposed to 5 N HCl then to 1% NaOCl. The thickness of the hybrid layer and the dimensions of the resin tags were measured using scanning electron microscopy (SEM) pictures and an image analysis software. RESULTS: When acid etching was performed, a hybrid layer as well as the characteristic funnel-shaped resin tags were observed. When Er:YAG laser was used alone, no hybrid layer could be detected. The resin tags appeared thinner and exhibited a cylindrical shape. CONCLUSIONS: The acid pre-treatment of the irradiated surface allowed both the seal of the dentinal surface and the increase of the diameter of the resin tags.

Composite Resins↗

PubMed2004

Morpho-structural aspects of Er:YAG-prepared class V cavities.

OBJECTIVE: The aim of this study was to evaluate the ability of an Er:YAG laser (2960nm) to prepare class V cavities as compared with rotary instruments. MATERIALS AND METHODS: Twenty-six freshly extracted human molars were selected and randomly distributed in two groups. Non standardized class V cavities were prepared using (group 1) a diamond bur for enamel, plus a tungsten bur for dentin with water irrigation and (group 2) an Er:YAG laser (output parameters, enamel: 1000 mJ, 12Hz, dentin: 500 mJ, 20Hz) with a continuous flow of water. RESULTS: The SEM examination revealed characteristic micro-irregularities of the lased samples as compared with the conventional prepared cavities: group 1, the walls of the cavities were slightly curved and a smear layer plus muds covered peripheric walls as well as the depth of the cavity; rare dentinal tubules were opened; linear and circular surface irregularities were observed on the dentin; and group 2, the walls of the cavities were irregular, jagged; photo-ablation creates a real cleavage of hydroxyapatite prisms with respect to the enamel prism pathway; an homogeneous dentin with opened dentinal tubules covered the depth of the cavities; intertubular dentin is selectively more ablated than Er-YAG the peritubular dentin. CONCLUSIONS: Jagged outline as well as opened dentinal tubules are the main characteristics of the Er-YAG prepared class V cavities. Further investigations (ulstrastructural, histochemical properties of the lased dentin, resistance to traction of bonded resins) should be conducted.

Dental Cavity Preparation↗

PubMed2004

Microleakage of a pit-and-fissure sealant: effect of air-abrasion compared with classical enamel preparations.

PURPOSE: The aim of this study was to assess the microleakage of a pit-and-fissure sealant after classical enamel preparations (prophylaxis followed by acid etching alone and mechanical widening with bur) and after air abrasion. MATERIALS AND METHODS: Ninety noncarious freshly extracted third molars were randomly assigned to three groups of 30. In each group, the mesial halves of the fissures were treated with air abrasion and conditioned with acid etching for 15 s. In group 1, the distal halves were treated with acid etching alone. In group 2, the distal halves of the fissures were widened mechanically with a bur and etched for 15 s. In group 3, the distal halves were prepared with air abrasion alone. Then the sealant (Clinpro) was applied on the occlusal fissures of all teeth, according to the manufacturer's recommendations. The teeth were thermocycled and the samples placed in a 1% methylene blue dye solution. The teeth showing microleakage and the means of infiltration were assessed with an image analysis system. RESULTS: The microleakage of sealants prepared with air abrasion alone displayed significantly greater microleakage (80%) (p < 0.0001) than the ones placed after prophylaxis and etching (13.33%), bur and etching (20%), or air abrasion and etching (22.2%). The samples prepared with air abrasion alone also showed the highest mean microleakage (1.14 +/- 1.4 mm) when compared to samples receiving prophylaxis and acid etching (0.12 +/- 0.41), bur and acid etching (0.08 +/- 0.26), or air abrasion and acid etching (0.09 +/- 0.4) (p < 0.05). No significant difference was noted between the three types of enamel preparation when etching was performed. CONCLUSION: Air-abrasion treatment does not eliminate the need for etching the enamel surface before applying the sealant.

Acid Etching, Dental↗