[Early treatment of mandibular incisor-canine crowding]. / Traitement précoce de l'encombrement incisivo-canin mandibulaire.

In the mixed dentition, lower incisor crowding can exist. He may be transitory or increase with dental arch evolution because of reduction of arch length by loss of leeway space. Early diagnosis allows the instauration of interceptive therapy, to ovoid extractions. Preserve or loss leeway space will depend of orthodontic space management. The clinical case presented in this article shows the interest of early treatment of incisor crowding to preserve arch length and make the leeway space available to resolve the crowding.

[The effect of autoclave sterilization on the surface properties of orthodontic brackets after fitting in the mouth]. / Effet de la stérilisation par autoclave sur l'état de surface des bagues orthodontiques après essayage en bouche.

Repeated sterilizations of the orthodontic bands, after fitting in mouth, are likely to involve modifications of their surface properties. Through this study we have tried to observe the effect of sterilization by autoclave on the surface of the orthodontic bands, as well as the contribution of the use of ultrasound in the chain of sterilization. The sample was composed of 30 orthodontic bands divided into 5 groups: a group of new bands (witnesses) and 4 groups having undergone respectively 1 cycle, 3 cycles, 5 cycles and 7 cycles of autoclave sterilization according to the World Health Organization recommendations. For half of each group bands, ultrasonic cleaning has not been provided. The scanning electron microscopy with the elementary microanalysis by X-rays was used for the investigation of surface. At the exam, new bands showed surface irregularities probably due to manufacturing procedures. And the bands, without ultrasonic cleaning, showed the presence of contamination and discolourations. Moreover, there were no modifications on the surface of the bands cleaned by ultrasounds before sterilization. The presence of surface irregularities associated with deposits observed on the bands surface, may be the site of bio corrosion by contributing bio film accumulation. The stay duration of the orthodontic bands in mouth, during orthodontic treatment, is important. So the effect of sterilization on the surface of the orthodontic bands must encourage other scientific research to determine the long term effects of sterilization which remains an essential process in our daily practice.

[Loss of molar anchorage: quantitative evaluation with a method of structural superposition]. / Perte d'ancrage molaire: évaluation quantitative avec une méthode de superpositions structurales.

The goal of this study is to analyze using structural cephalometric superimpositions the quantity of mesial molar drift in the maximum anchorage cases, with mainly extractions of the first four premolars. Molar anchorage is appreciated in cases treated with or without use of directional forces. The influence of various parameters: age, facial divergence, discrepancy and incisor repositioning, on the loss of anchorage is also evaluated. The statistical study called upon the test of Student for independent groups. A value of the risk of first species p<0.05 was considered as significant. The loss of anchorage seems less important with the use of the directional forces. On the other hand it is raised in teenagers and the cases of important incisor repositioning.

[Intermaxillary tooth size discrepancies with reference to the Bolton index in a Moroccan population]. / Etude de la dysharmonie dento-dentaire à travers l'indice de BOLTON dans une population Marocaine.

This study has for purpose the evaluation of the frequency of inter-dental disharmony in a Moroccan population via the BOLTON index. Using image processing of their dental moulds, the BOLTON index was measured in 30 patients at the Dentol-Facial Orthopedics Department of Rabat. It results that a high percentage of patients was outside the 2 SD BOLTON interval. Several patients presented significant disharmony that could affect their orthodontic treatments and should be taken into consideration while establishing the proper treatment.

[Clinical study of vertical dimension before and after orthodontic treatment in a Class II population]. / Etude clinique comparative du sens vertical avant et après traitement orthodontique chez une population de classe II squelettique.

The authors tried to highlight orthodontics only or mixed "orthopedics + orthodontics" repercussions about vertical dimensions while comparing the measurements before and after treatment done on teleradiographies of profile of 30 hyperdivergent and hypodivergent patients with skeletal class II. The clinical conclusions have been drawn after discussion of the results.