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Biomedical subjects

M Delatte

Publications and source records attributed to M Delatte.

9 recordsLinked to original sources

[Prevention and treatment of dento-maxillary discrepancy].

The many clinical and radiological signs of arch length discrepancy simplify the practitioner's task of diagnosing it early. When they need to deal with insufficient room in the dental arch, orthodontists have available to them a large variety of therapeutic possibilities that require relatively little cooperation from young patients and that often work quickly to correct beginning malocclusions in the mixed dentition or that prevent them from worsening. Orthodontists decide whether to use space maintainers, increase arch length, or embark on a program of serial extraction depending upon the type of disorder, its severity, and its etiology. The principle objectives of early treatment in arch length discrepancy cases are to re-establish a balanced occlusion and to reduce the duration and the complexity of definitive treatment in the adult dentition.

Cephalometry↗

Regulatory effects of FGF-2 on the growth of mandibular condyles and femoral heads from newborn rats.

The secondary cartilage of the mandibular condyle is considered to be adaptive to functional factors. In the last decades, growth factors have also been shown to be potent regulators of cartilage metabolism. Moreover, it has been suggested that growth factors may differentially regulate the growth of primary and secondary cartilages. However, only a few studies have made a direct comparison of the effects of growth factors on both cartilages. Therefore, the aim here was to compare the effects of FGF-2 on secondary cartilage of the mandibular condyle and primary cartilage of the femoral head from 4-day-old rats in vitro. Cartilages were cultured for 1, 7 and 14 days with 0 and 100 ng/mL FGF-2. We evaluated the effects of FGF-2 on growth, tissue organisation, DNA and glycosaminoglycan (GAG) synthesis and GAG and collagen content. With FGF-2, the morphology of the mandibular condyles changed and the GAG and collagen contents were reduced. However, the growth of the mandibular condyles was not affected. On the contrary, the growth of the femoral heads was strongly reduced due to an inhibition of chondrocyte hypertrophy. In both cartilages, FGF-2 stimulated DNA synthesis in short-term cultures and reduced it in long-term cultures. In conclusion, FGF-2 had a larger effect on the metabolism of the mandibular condyles as compared to the femoral heads. However, the growth of the femoral heads was strongly reduced while that of the mandibular condyles was not affected.

Animals↗

Growth stimulation of mandibular condyles and femoral heads of newborn rats by IGF-I.

Primary and secondary cartilage differ in embryonic origin and are generally considered to have a different mode of growth. However, few experimental studies exist that directly compare the two types of cartilage and their growth regulation. The regulation of cartilage growth is a complex mechanism involving growth factors like insulin-like growth factor-I (IGF-I). The purpose of this study was to compare the growth of mandibular condyles of 4-day-old rats with that of femoral heads in vitro and to analyze the effects of IGF-I. Explants were cultured for up to 2 weeks with 0, 5, and 25 ng/ml IGF-1. Both, 5 and 25 ng/ml IGF-I significantly stimulated growth of the mandibular condyles while only 25 ng/ml IGF-I stimulated growth of the femoral heads. IGF-I increased glycosaminoglycan synthesis of both condylar and femoral cartilage. However, only the DNA synthesis of the mandibular condyles was significantly increased by IGF-I while that of the femoral heads was not affected. It is concluded that IGF-I stimulates growth of both secondary condylar cartilage and primary femoral cartilage. The mandibular condyle appears to be more sensitive to IGF-I than the femoral head, which may partly be due to the different developmental stage.

Animals↗

[Indications for orthognathic surgery, the limitations of orthodontics and of surgery].

The different sagittal, vertical or transversal skeletal dysmorphosis can be treated with orthodontic or orthopaedic appliances. Certain limits of treatment will be due to the age of the patient, the importance of the skeletal dysmorphosis, technical limits of the orthodontic appliances or the motivation and compliance needed from the patient. For this reason an orthodontic treatment combined with orthognathic surgery may be indicated. Nevertheless the combined orthodontic-surgical treatment has also its limitations and specific treatment needs from orthodontist and maxillo-facial surgeon.

Adolescent↗

[Pre- and post-surgical orthodontic objectives and orthodontic preparation].

Orthodontics in combination with orthognathic surgery is a possibility today for correcting sagittal, vertical and transversal dysmorphosis. To do this, orthodontic preparation before surgery is necessary. In the sagittal plane, dental compensations should be removed. In the vertical plane, levelling of a severe mandibular SPEE curve should be accomplished postsurgically, and transverse coordination obtained. Orthodontic preparation is very specific to the type of dysmorphosis: class II malocclusion, class III malocclusion or in open bite. Postsurgical orthodontic treatment is used to finalize tooth alignment as in conventional orthodontics.

Craniofacial Abnormalities↗

[Extraction in orthodontics: when and why?].

During the last century orthodontic treatment philosophies changed continuously. The necessity to extract teeth in order to correct a lack of space has many times been the subject of discussion. In fact there exists several techniques which make it possible to avoid extractions in many cases. A number of criteria which influence the decision to extract or not, as well as some techniques to regain space in upper and lower arch are discussed.

Malocclusion↗