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Biomedical subjects

L Deblock

Publications and source records attributed to L Deblock.

At least 19 recordsLinked to original sources
PubMed2006

Improvement of pseudoelasticity and ductility of Beta III titanium alloy--application to orthodontic wires.

The pseudoelasticity of metastable Beta III titanium alloy (TMAtrade mark) used for orthodontic applications is obtained by cold wiredrawing. This wire has higher rigidity than cold-drawn NiTi (Nitinoltrade mark, superelastic NiTi SE) and lower recoverable deformation. The low ductility value of Beta III is due to the deformation imposed by wiredrawing. The aim of this research was to improve the behaviour of this alloy by modifying the microstructural parameters to decrease the rigidity and increase the recoverable deformation and ductility of the alloy. The effects of second phase precipitate, grain size, and deformation on the wire mechanical properties were also examined. The isothermal precipitation of alpha (alpha) or omega (omega(isoth)) phases precludes the expression of the pseudoelastic effect. The presence of an omega(isoth) phase considerably increases fracture strength, whereas the alpha phase strongly decreases the ductility and adversely affects the strain recovery (epsilon(r)). To control the grain size, the growth of the recrystallized grains was studied by considering several parameters, which are known to have an influence on grain size, including the cold rolled strain, the temperature, the time of annealing, and the initial grain size. A structure with coarse grains, quenched from a temperature higher than the beta transus (T(beta)), associated with a plastic pre-deformation, contributed to an improved pseudoelastic behaviour, due to the presence of a reversible martensite phase (alpha'') induced by the pre-deformation.

Dental Alloys↗
PubMed2003

[Vertical superposition on distance radiography in norma lateralis: normal or asymmetrical?].

Cephalometric analysis, together with clinical examination and study of models, is an essential tool in practitioners' preparations of orthodontic diagnoses for their patients. However, despite the use of standardized techniques, cephalograms in norma lateralis still inescapably superimpose patients' right and left sides on each other. This study attempts to demonstrate the significance of these superimpositions particularly when serial cephalograms are themselves superimposed on each other to discern growth or treatment changes.

Artifacts↗
PubMed1998

[The development of craniomandibular disorders after bilateral sagittal osteotomy].

The aim of this study is to know the repercussions of modified sagittal ramus split osteotomy of the mandible on the anamnesic symptoms of cranio-mandibular disorders in 89 patients. The sample was divided into different groups according to the surgery type: mandibular advancement or mandibular retrusion with or without maxillary surgery. The anamnesic approach allows to evaluate the felt symptoms. All had a surgery by the same surgeon and with the same technique: mandibular sagittal bilateral surgery according to the modificated Obwegeser osteotomy. The statistical analysis shows some differences between groups.

Adolescent↗
PubMed1997

[The Burstone technic: extremely light forces and pressures].

During orthodontic displacement, integrity of root and periodontis needs the knowledge of forces systems developed by orthodontic appliances. Analyses of different tooth movement require some biomechanic rules especially to choose magnitude and direction of forces, with respect to the center of resistance and the C/F ratio. Forces systems developed by the Burstone segmented arch technique have to be shown biologic because they produce light and variable pressures according to patient age and rate of periodontal disease.

Adult↗
PubMed1992

[The potentiality of antero-posterior orthodontic extraoral traction: clinical and cephalometric results].

Heavy posterior orthopedic forces used for massive retropositioning of maxillary bone are among the orthopedic treatments preconised during mixed dentition. The clinical and cephalometric results of twelve cases treated by these means indicate that only dental movements can be obtained without the possibility of any orthopedic remodeling. These results corroborate those of other studies and it is possible to conclude that heavy orthopedic forces represent a very imprecise therapy which lead to side effects that are greater than the desired objectives.

Cephalometry↗
PubMed1992

[The use of growth prediction and V.T.O.: special concepts].

Growth induces very important modifications of the skeletal positions of the maxilla and the mandible and the precise position of the teeth is not foreseeable before an attempt to evaluate the situation the bones will be in by the end of the treatment has been made. Predictability factors are examined and a specific construction of V.T.O. is suggested. Then a new superposition is proposed which allows to determine the direction and range of teeth displacements.

Cephalometry↗