[A particular temporomandibular disorder: the temporomandibular joint ankylosis. Basic and clinical concepts]. / Un trouble temporo-mandibulaire particulier : l'ankylose. Notions fondamentales et cliniques.

Ankylosis of the temporomandibular joint mostly affects children and young adults. Although it is rare, it is an extremely debilitating disease whose effects on growth, morphological development and personal development are significant. To manage this disorder, it is essential to be informed about the causes, about the anatomical shapes it presents and about its symptoms. This knowledge will also help us choose the most appropriate therapy, that may nevertheless result in failures and in relapses requiring prosthetic rehabilitation.

Attempted validation of a method to locate entry and exit foramens of the branches of the trigeminal nerve; benefits for an original cephalometric analysis technique.

INTRODUCTION: Trigeminal analysis focuses on the skeletal entrance and exit orifices of the sensitive fibers of the trigeminal nerve. The aim of this study was to validate the techniques used to locate these landmarks as described by the creator of trigeminal analysis of the face. MATERIALS AND METHOD: This descriptive study was performed on a dry human skull. Two tin balls forming markers R1 and R2 were fixed at random on the skull in a median sagittal position. Two headfilms of the skull were made. The first showed tin balls fixed at the entrance and exit foramens of the sensitive fibers of the trigeminal nerve. The second showed the foramens without the tin balls. The position of the reference point corresponding to the entrance and exit points of the trigeminal fibers was entered on a tracing made from the headfilm (without the balls on the foramens) by 16 operators using an ad hoc guide supplied by Crocquet. A comparison was made between the points as positioned by these operators and the true points as revealed by the X-rays of the balls on the first image (Gold Standard) by calculating the difference between their coordinates on an axis connecting R1 et R2 (X-axis) and the line perpendicular to it passing through R2 (Y-axis). Trigeminal cephalometric analysis was then performed on each of the tracings. The angles and linear values were compared. The validity of the positioning of the points and of the values provided by the analysis was demonstrated by the existence of a difference of less than 2units (mm or degrees). RESULTS: No difference in the means between the trigeminal points found by the operators and the Gold Standard points represented by the X-rays of the balls placed on the foramens exceeded 2mm in absolute value on the Y-axis. On the X-axis, the differences greater than 2mm in absolute value related to: the supra-orbital notch (ESO) and the foramen ovale (FO) (2.12 and 8.19mm, respectively). The angles (ESO-TGR-TO) and (TGR-ESO-TSO) were the only ones to display differences exceeding 2° in absolute value between the two images. CONCLUSION: The detection method advanced by Crocquet for the positioning of the eight points of reference used for analyzing the entrance and exit foramens of the trigeminal nerve is valid apart from the TO and ESO points. Consequently, the validity of the angle measurements involving these points is affected. Further research is required to confirm these findings. If necessary, new recommendations should be devised in order to improve the localization of the TO and ESO cephalometric points.

[Planning dental care and orthodontic treatment for children afflicted with malignant hematological diseases]. / Planification des soins bucco-dentaires et des traitements ODF chez les enfants atteints d'une hémopathie maligne.

THE PROBLEM: In France, cancer affects 1 to 3% of all children and represents the second most frequent cause of mortality among children younger than fifteen. Malignant blood diseases are the most frequently occurring childhood cancers. Although their mortality rate has been tending to decrease, they often seem to develop after "opportunistic" latent infections persist, undetected, in un-eradicated sites that may be of dental origin. This infectious risk, frequently undiagnosed in hospitals, should be of concern to both general dentists and orthodontists. OBJECTIVES: General dentists and orthodontists each have specific roles to play in teaching children about oral health at an early age and in detecting and eradicating infection as well as in seeing at risk children in regular follow-up visits. DISCUSSION: Dentists should examine children on regularly scheduled preventive appointments and treat dental caries when they discover it. Orthodontists, who see the children they are treating on frequently scheduled appointments, should always be on the alert for incipient caries in their patients and be careful to make the appliances they wear as well fitting and non-irritating as possible to minimize the risk of inflammation and development of sore spots. Both dentists and orthodontists should teach their patients how to maintain healthy diets and good oral hygiene. They may be called upon to provide local relief for acute lesions that chemotherapy sometimes causes in the soft tissues of patients with hematological cancers and to modify irritating appliances.

Evaluation of dentoskeletal parameters in Senegalese subjects using orthodontic architectural analysis.

INTRODUCTION: The aim of this study was to determine the morphological characteristics of a Senegalese population based on an architectural cephalometric analysis. PATIENTS AND METHODS: One hundred and five lateral cephalograms of Senegalese patients were assessed in a cross-sectional study. All lateral cephalometric films were traced on a transparent cellulose acetate sheet by the same operator. Danguy architectural analysis was performed with 11 measurements (seven linear and four angular). T-test was used to assess differences in cephalometric variables between subjects grouped according to gender (male and female) and age bracket (<12 years and ≥12 years). Significance was set at p≤0.05. RESULTS: This study shows that this Senegalese sample had a skeletal class II tendency associated with backward mandibular rotation. The divergence of masticatory corner appears to be greater than in Caucasians with more vertical facial growth. No statistically significant differences were found between men and women. As compared to the under 12 years subgroup, the over 12 years subgroup shows significant increase in maxillary and mandibular lengths whereas skeletal divergence evidenced the opposite tendency and the difference with the under 12 subgroup was significant. Lastly, the first molar underwent significantly greater mesial drift in the 12 and over sub-group. CONCLUSION: Danguy architectural analysis provides a good reliable comparative assessment of facial structures and offers an addition to conventional dimensional or typological analytical methods.

[Supraclusion origins]. / La genèse de la supraclusion.

Orthodontists often observe the clinical sign of supraclusion, or deep overbite, in their patients, a condition that is difficult to correct and that relapses frequently. In order to treat it with the most appropriate therapy, orthodontists should have a precise understanding of its etiology, which can be skeletal, neuromuscular, or dental and may often result from an intricate web of factors. In preparing their diagnoses, orthodontists should examine the possible mechanisms of its installation and evaluate them in an architectural cephalometric analysis of the oral prehensile complex.

[Value of trigeminal nerve foramina-based approach in the cephalometric study of sagittal morphology of Senegalese subjects]. / Intérêt d'une approche téléradiographique basée sur les entités trigéminales dans l'étude de la morphologie sagittale de sujets sénégalais.

INTRODUCTION: The aim of this study was to determine the morphological characteristics of a Senegalese population based on an original cephalometric analysis using landmarks corresponding to the bony entrance or emergence of sensory fibers of the trigeminal nerve. MATERIALS AND METHODS: One hundred and five lateral cephalograms of Senegalese patients were assessed in a cross sectional study. The landmarks used were based on cranial foramina i.e. ovale (TO), rotundum (TGR), supraorbital (ESO), infraorbital (TSO), incisive (CPA), lesser palatine (CPP), mandibular (IM) and mental (TM). Seven angular measurements were determined on each cephalogram. t test was used to assess differences in cephalometric variable between subjects grouped according to sex (male and female) and age bracket (< 12 years and > or = 12 years). The Pearson's correlation coefficient was used to analyze the relationship between the cephalometric trigeminal and conventional variables. The significance was set at p < 0.05. RESULTS: The Senegalese mesoface appear to be more retrusive and more divergent when compared with European standard. Regarding sexual differences, TRG-ESO-CPA angle shows significant sexual dimorphism, the maxillary mesofacial prognathism is more important for boys (p = 0.04). When compared to the < 12 years subgroup, the > 12 years subgroup shows significant increase in the mesofacial prognathism and a decrease in the mesofacial divergence but the difference was not significant. Maxillary and mandibular mesofacial prognathism were positively correlated respectively with SNA (r = 0.22; p = 0.021) and SNB (r = 0.28; p = 0.004). The latter were in addition negatively correlated with the mandibular angle Ar-Go-Me (r = - 0.20; p = 0.041). Lastly, the mesofacial divergence angle is positively correlated with the mandibular angle (r = 0.20; p = 0.044) and negatively correlated with SNB (r = - 0.22; p = 0.027). CONCLUSION: The trigeminal analysis based on true anatomical skeletal points provides a good way to assess facial structures and could allow proper forecasting of the dento-alveolar compensation and complement reliably conventional cephalometric analysis.

[Diagnosis and treatment of temporo-mandibular disorders in orthodontics]. / Détection et thérapeutique des troubles temporo-mandibulaires en orthodontie.

Orthodontists are fully prepared to treat the problems of occlusion that they are called upon to deal with every day. On the other hand temporo-mandibular joint disorders present more obscure difficulties from the point of view of detection and diagnosis as well the management of their treatment. That is why a profound understanding of the anatomical and physiological functioning of the temporo-mandibular joint has become indispensable for today's orthodontists who are now asked to detect and diagnose an assortment of TMJ disturbances whose etiology may vary greatly. By performing a rigorous diagnostic procedure, based on a thorough clinical examination supported by careful axiographic and radiological studies, of temporo-mandibular malfunctioning and its underlying etiological causes, which are primarily dento-alveolar and occlusal in nature, orthodontists will be able to adopt an appropriate therapeutic approach that might be purely orthodontic or multi-disciplinary and carried out with the collaboration of specialists in occlusion, oral surgery, and even osteopathy.