The morphological particularities of the posteriorly rotated mandible, first described by A. Björk, may correspond to extremely variable clinical situations. We can derive important information by analyzing the forms and proportions of different mandibular entities. This article proposes to illustrate the most frequently encountered situations by describing a number of cases of posterior rotation and by explaining how Delaire’s architectural analysis can be used in clinical practice.

The increasing number of questions posed by problems arising from the behavior of teenagers make it logical for us to ask whether or not we should consider adolescence to be a disease. The answer is obvious: of course not! And we can affirm that response with empirical evidence. Most adolescents we see in consultation do well without having any need for psychiatric assistance, an observation confirmed by a French Ministry of Health 2002 study that found only one out of eight adolescents suffered from mental disorders. This, of course, clearly implies that seven out of eight enjoy good mental health.

If adolescence is not a disease, it could become one if friends and families of teenagers fail to understand the profound changes these young people are passing through or misinterpret the manifestations of this crucial life stage.

In treating children who have a significant lack of space both for the correct placement of their teeth, in what is called an arch length discrepancy, as well as for proper accommodation of their airways resulting in the Obstructive Sleep Apnea Syndrome, it seems to us to be indispensable for specialists in dentofacial orthopedics and otolaryngology to share and combine their philosophies and treatment approaches. The three clinical cases that we are presenting in a virtually documentary cinemaphotographic fashion, dealing simultaneously with the skeletal, dental, and breathing aspects of the disorder, will, we hope, give an improved view of the landmarks and architecture of “facial insufficiency” and the ways in which it can be treated. Patients with “facial insufficiency” suffer from simultaneous impairment of the correct growth off the two maxillae. In addition, the failure of the two jaws to develop sagittally makes the problem difficult to detect. Patients with Class I bimaxillary retrusions make up the majority of patients seeking orthodontic treatment who have facial insufficiency. And it is only the oral examination the orthodontist makes about the lack of space for teeth that uncovers the accompanying problem of lack of space for the airways. It should be pointed out that not all patients with bimaxillary retrusions have insufficient airway space. Still orthopedic treatment of the dental problem, enlarging available space in the dental arches, also automatically increases available airway space. This procedure must await the restart of vertical posterior growth under the influence of upward pressure from the tongue against palatal supports that stimulate the mandibular condyles. It is understandable, then, that any blockage of nasal breathing, from, for example the inferior turbinates or enlarged adenoidal tissue or impediment to vertical tongue thrusts, from excess tonsilar tissue or tight lingual frenums would be a primary hindrance to the desired growth process. So the first orthodontic objective is freeing the tongue, the second is adjusting occlusion. Ramus growth, in fact, unlocks a verticotransverse “raising” action of the lower lateral sectors needed for occlusal recovery and advancement of the maxilla. The “mandibular lock” blocking maxillary advancement is thus opened vertically.

Orthodontics has been developing for 282 years. We can distinguish an initial period when practitioners limited themselves to “straightening” teeth that were out of position. Then, under the influence of Edward Hartley Angle, they devoted their efforts to correcting “malocclusions.” Now, during its third period, orthodontics has divided itself into two branches. The American school believes the shape and size of basal bone is genetically determined and that treatment should be limited to the dentition, which must be positioned in conformity to precisely defined standards. But the European school is persuaded that basal bone can be modeled by the play of functional forces, which treatment can change and thereby adjust growth and development. What will be the guiding principle of the orthodontics of tomorrow ?

Today there is near universal agreement that the cephalometric analyses presented by the Americans Ricketts, Steiner, and Tweed need to be re-evaluated and brought up to date. To this end, our C.R.A.N.I.O.M group has prepared a new method for using cephalometric numerical and angular readings in the preparation of a reasonable and well-reasoned aid to diagnosis.

We analyzed the data from a sample of 83 young adults with Class I occlusions, none of whom had ever received orthodontic treatment.

In our work the most striking new consideration that we employed was to use the extreme values for each variable of this sample. These figures constitute extreme parameter limits very distant from each other: for example there is a gap of 30° between the most buccally inclined incisor and the most lingually, or palatally, inclined.

Therefore, we found incisor inclination to be acceptable within a range of 78 to 114° to Downs’s mandibular plane on the lower arch and from 97.5 to 130.1° to the Frankfort plane for the upper arch. So in our reasoning there is far less need to reposition these teeth in conformity to an arbitrary cephalometric norm.

And, for the same reason, we find far fewer cases requiring extraction in order to allow orthodontists to achieve results that satisfy abusive standards established by Ricketts, Steiner, and Tweed. The osseous measurements that we report simply describe the forms we observed, none of which constitute anomalies but, instead, describe a particular type.

The C.R.A.N.I.O.M group believes that cephalometric analysis occupies a place in orthodontic record taking that comes after those occupied by esthetics, periodontal status, and muscular balance.