Functional orthodontics

Lateral cephalogram (tele-X-ray) of the head

For a detailed analysis of dentofacial anomalies, a lateral head radiograph is used. On the obtained image, the doctor visualizes the bones of the facial and neurocranium, the cervical spine, as well as the dentition and soft tissue contours of the profile.

A key feature of the method is performing cephalometric analysis. Tracing is performed over the X-ray image: contours of anatomical structures are outlined, reference points are set, lines are drawn, and angles are measured.

In orthodontics and maxillofacial surgery, lateral cephalometry allows solving several tasks at once:

• Assess the vector and growth pattern of the facial skeleton.
• Identify sagittal and vertical anomalies (positions of the upper and lower jaws relative to the cranial base).
• Analyze incisor inclination.
• Plan orthodontic intervention or orthognathic surgery.
• Study facial aesthetics by comparing bone structures with profile soft tissues.

Hand radiograph and bone age

The direct projection of the hand and wrist is the "gold standard" for determining bone (skeletal) age. The image evaluates the distal ulna and radius, carpal bones (ossa carpi), metacarpal bones (ossa metacarpi), and finger phalanges (phalanges).

Special attention is paid to specific zones: the distal radial epiphysis, as well as the epiphyses of the metacarpals and phalanges. The doctor analyzes the shape, size, and presence of ossification centers, as well as the stage of synostosis—the degree of fusion of metaphyses with epiphyses.

For functional orthodontics, this method is of decisive importance. It helps to accurately determine the peak of the patient's pubertal growth. It is during this period that the use of functional orthodontic appliances aimed at stimulating jaw growth yields the maximum clinical effect. In addition, the technique is actively used in endocrinology and pediatrics to detect premature or delayed physical development.

Physiological rationale for dental interventions

Physiology of the maxillofacial region is the foundation that turns a set of manual skills into meaningful medical practice. Processes such as chewing, swallowing, speech, salivation, and taste reception constitute a single functional system. The doctor interacts with it at every stage: from the initial examination to the fixation of a complex prosthetic structure.

Knowledge of normal physiology is directly applied in various branches of dentistry:

• Gnathology and occlusal diagnostics are based on an understanding of the reflex regulation of the masticatory cycle and the biomechanics of masticatory muscles.
• Caries prevention and treatment of salivary gland diseases (sialadenitis, xerostomia) are impossible without knowing the mechanisms of salivation.
• Assessment of taste disorders (for example, after anesthesia or prosthetics) requires an understanding of taste reception.

Any intervention that changes the shape of the hard palate or dentition (including orthodontic treatment) inevitably affects articulation and the act of swallowing, which requires the specialist to account for sensory and reflex mechanisms.

Mechanisms of pain sensitivity

The physiology of toothache is of particular practical importance. Competent interpretation of patient complaints, planning of endodontic treatment, and selection of an adequate method of anesthesia are based on knowledge of pulp innervation and the functions of odontoblasts.

A key role here is played by the hydrodynamic theory of dentin pain, which explains the mechanisms of pain occurrence in response to external stimuli. Without this theoretical base, the dentist's clinical thinking remains incomplete, as the form of anatomical tissues is inseparable from their function.

Class and exam questions

What else to study on this topic

• Cephalometric analysis: reference points, lines, and angles on lateral cephalograms.
• Sagittal and vertical anomalies of jaw position.
• Ossification centers and stages of synostosis on a hand radiograph.
• Biomechanics of masticatory muscles and reflex regulation of the masticatory cycle.
• Hydrodynamic theory of dentin pain and pulp innervation.

Other topics in the "Additional Topics" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.