[Orthopedic aspects of Distal Active Concept therapy applied in the mixed dentition. Comparative study with an untreated population]. / Aspects orthopédiques de la thérapeutique Dac appliquée a la denture mixte. Etude comparative avec une population non traitée.

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.

Electrochemical and cytocompatibility assessment of NiTiNOL memory shape alloy for orthodontic use.

Orthodontic arcs and wires are mostly realised from alloys and constitute the motor of dental shifting. Ti-base alloys rapidly replaced the formerly used stainless steel wires due to their excellent corrosion resistance, their high mechanical characteristics and their increased biocompatibility. NiTiNOL shape memory alloys add to these advantages their ability of deforming force. NiTiNOL, highly pure Nickel (hp-Ni) and commercially pure titanium (cp-Ti) were tested by electrochemical assays in artificial saliva and in vitro biological tests with L132 cells and HEPM cells. All tests gave concordant results: the electrochemical assays, the proliferation test, the colony forming method, and the inflammatory test clearly show, that nickel is a corrosive and a cytotoxic material. Ti and NiTiNOL are cytocompatible and in particular corrosion resistant. No significant differences are observed for both materials on the electrochemical and the biological level as well. The NiTiNOL shape memory alloy is a master trump for dental practitioners to repair occlusal defects by shifting teeth under optimal biological conditions. In spite of its high Ni-content, it is biocompatible. It considerably reduces the tune of therapeutic treatment, facilitate the occlusal concept and leads to a result of high clinical quality.