[Functional treatment of children subcondylar fractures: An axiographic assessment]

INTRODUCTION

Subcondylar fractures are common in children. Occlusion disorders resulting from these fractures in deciduous or mixed dentition do not have as much impact as in adults due to alveolar adaption possibilities. Functional treatment allows for good functional results, but does not treat the dynamic shortening of the ramus. The objective of this study was to evaluate the axiographic condylar slope changes after subcondylar fracture in children.

MATERIALS AND METHODS

A prospective study was conducted from 2010 to 2015, including all the under-18 patients presenting with a subcondylar fracture. Examination by mean of a Quick Axis axiograph measured the length of propulsion and the condylar inclination on both sides. The main evaluation criterion was the amount of condylar inclination decrease on the fractured side.

RESULTS

Twelve patients (mean age: 10.42; 5-16) were included. Eleven children had a loss of condylar inclination on the fractured side without occlusion disorders at 33.2 months on average (3-144 months) after the initial trauma. Only one patient had symmetric axiographies without loss of condylar inclination on the fractured side.

DISCUSSION

Dynamic shortening of the ramus on the side of the subcondylar fracture is consistent at short and medium terms in children. Surgical treatment may be the solution for avoiding this dynamic disorder of the mandible and should be evaluated.

[Diagnosis and treatment of temporo-mandibular disorders in orthodontics]

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.

The curve of Spee: understanding the sagittal organization of mandibular teeth

The tangent law explained the sagittal organization of the mandibular teeth by geometrical analyses. According to this concept, the long axis of all mandibular teeth must converge at one point in the circle of the "curve of Spee", and this point is diametrically opposed to the condylar point. A cephalometric analysis of 470 patients was the basis for this statistical study of the radius of the curve of Spee. The mean radius was approximately 80 mm. The mandibular incisors followed the tangent law, but the long axis of the posterior mandibular teeth exhibited a progressive differential angle (postero-anterior) with the direction of the tangent (15 degrees, 20 degrees, 25 degrees, 28 degrees). This differential angle generates a horizontal strength component with tendency to forward tooth movement, tightening of the proximal contacts. The use of this cephalometric reference could help the dentist to determine a more suitable organization of the occlusion in the sagittal plane.

Evaluation of the relationship between anterior and posterior functionally disclusive angles. Part II: Study of a population

The lateral and protrusive anterior and posterior disclusive angles were recorded and measured by using a newly developed method (part I) on a population of 50 subjects (mean age 27.2 years). All of the subjects had natural anterior teeth, 45 had a clinically acceptable anterior guidance, and the remaining five had a partial (unilateral) or total lack of anterior guidance. A statistically significant correlation between the anterior and posterior disclusive angles was not found either in the entire population (n = 50) or in the stratum of the population that consisted of subjects with a clinically acceptable anterior guidance (n = 45). The Angle class of occlusion or anterior deep bite malocclusion were not identified as possible confounders or effect modifiers. This study suggested that the intra-articular tissues of the temporomandibular joint played a significant role in the relationship of their osseous components. Practical guidelines to determine anterior guidance could be established by using population means.

Evaluation of the relationship between anterior and posterior functionally disclusive angles. Part I: Literature review, instrumentation, and reproducibility

Authors are not in agreement concerning the existence of an anatomofunctional interrelationship between condylar and anterior guidances of the mandible in humans. Current literature consists either of speculative statements or studies omitting the role of the meniscus. This article (part I) describes a unique method to correlate the condylar functional anatomy to the lingual inclines of the maxillary anterior teeth (anterior guidance) and acknowledges all components of the temporomandibular joint. The measurements obtained by means of this method were reproduced five different times on five different subjects, making possible a valid statistical analysis of the correlation between condylar and anterior guidances of the mandible (part II).