Biomedical subjects
Publications and source records attributed to J J Aknin.
Treatment of Class II malocclusion during the mixed dentition may sometimes require upper molar distalization. To achieve this, many devices have been suggested. The purpose of this article is to classify them and to point out their effects on the dentition and upon skeletal structures.
The presentation of a synoptic chart allowing a dental arch analysis and Class II correction strategy is presented and followed by a study on 30 patients in mixed dentition and 37 growing patients in permanent dentition. These patients presenting a Class II malocclusion have been treated by Class II mechanics and lower molar individualised splint enhancing the vertical lower face height and skeletal Class II correction. This study shows a good vertical stabilization of the facial planes during the treatment, a significant growth of the lower face but it is noticed a posterior rotation of the occlusal plane in the mixed dentition sample.
Our present study compares the skeletal and dentoalveolar changes between 120 subjects in mixed dentition treated with "Distal Active Concept" therapy versus 157 untreated subjects of class II served as a control group. Upon considering the treated subjects, a highly significant difference of mandibular growth (p < or = 0.001) with an anticlockwise rotation is noticed. The comparisons done according to gender and facial divergence show that the linear measurements are greater in males than females but the vertical relations are identical. Moreover, when considering hypodivergent and normodivergent subjects, all cephalometric values are similar and when regarding treated or non treated subjects, a significant difference of vertical growth factors exists and prevails. After comparaison, results clarify the benefits of early treatment for Class II malocclusion when the skeletal imbalance is considerable as it causes a quick mandibular response and hence improving the facial harmony dramatically.
Cleidocranial dysplasia is a bony autosomal dominant disorder, defined by late closure of fontanels and sutures, clavicular aplasia or hypoplasia and supernumerary teeth. The aim of our study was to define the CBFA1 mutations in three families with cleidocranial dysplasia and to describe the phenotype expression within and between the families. While the mutation R225Q caused a similar phenotype within one family, the mutation G146R, located in the same domain, was the cause of a variable expression between two family members. A third mutation, R190Q was responsible for symptoms not commonly associated with this disorder. The results of our craniofacial examination are in agreement with the numerous descriptions in the literature. This study accents the difficulty in establishing a clinical based diagnosis due to the wide variability.
The TWA (Top Wire Appliance) bracket enables a vertical insertion of the rectangular orthodontic archwire. This updated biomechanical evolution of the TWA technique promotes corrections during the first therapeutic stages of a fixed treatment. This bracket has been designed to take full advantage of the properties of shape memory archwires, reducing chairtime and making deep bite correction easier, dental rotations, alignment, leveling and stabilization, thanks to the rigidity of the vertically inserted arch, working heightwise. Progressive tightening ligature, adapted to the therapeutic sequence in progress is an element of biomechanics in TWA technique.
The "Distal Active Concept" (DAC) therapy used during the mixed dentition period shows a mandibular growth of 7.6 mm whereas the same treatment applied on the permanent dentition only shows a mandibular growth of 3.9 mm. This difference is highly significant. The DAC therapy is prescribed to a group of 30 nine years old patients with a mixed dentition for six months. The DAC therapy is prescribed to a group of 34 twelve years old patients with a permanent dentition for 24 months. As the mandibular answer to treatment seems to be more effective at the age of 9 than later, during the prepubertal period, the DAC therapy appears to be of interest and an alternative to activator treatments. Our results show the efficiency of a first stage treatment, for all the patients showing a significant class II malocclusion.
The "Distal Active Concept" therapy, favours an immediate repositioning of the mandible and introduces new therapeutic sequences which allow an easy correction of the Class II molar relationship, enhancing the mandibular growth simultaneously. The "Distal Active Concept" therapy is a combined treatment which induces the correction of the Class II malocclusion without extractions and without headgear. The dento-alveolar unit is used as a functional matrix to free, then enhance the mandibular growth and induce its counter-clockwise rotation. 35 patients treated with the "Distal Active Concept" therapy are compared to 33 patients, treated with the extraction of four bicuspids and in Edgewise therapy, in order to visualize the mandibular growth and the counterbalancing rotation described by Dibbets.
A statistical study of 30 cases treated in Edgewise technic shows the orthopedic effects of this technic upon adolescent patients who have a Class II, division 1 malocclusion. The Harvold's triangle and Mac Namara's analysis show the sagittal break of the maxillary growth, the significant acceleration of the horizontal growth of the mandible and the stabilization of the vertical growth of the face. The results are compared to the initial situation and to a prevision of growth without treatment.
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The patient who present a deep bite pattern with a low FMA angle have contradictional functional and esthetic objectives. The cephalometric alarm signs help the clinician to locate the esthetic risks.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
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