Instrumental diagnostic methods
To accurately plan treatment, objective methods for assessing the maxillofacial region are used:
- Measurement of dental casts. The physician performs detailed biometric calculations. Digital 3D models of the upper and lower jaws are often used for this purpose, on which special reference points are placed.
- Axiography. This is a specialized instrumental method that makes it possible to record the trajectories along which the mandible and the elements of the temporomandibular joint move. The procedure is performed using a complex extraoral device.
Orthodontic instruments: cutters and pliers
Working with bracket systems and wire arches requires high-precision instruments made of high-strength alloys.
Ligature cutters are designed to work with soft elements of the system. They are used to cut ligature wire, shorten working arches, and slice elastics. Their working part features straight-converging, sharply sharpened blades. The sharpening angle and edge thickness vary depending on the cross-section of the wire to be cut.
Distal end cutters are used strictly for cutting free ends of the arch distally (behind) the buccal tube lock. They feature a complex working part: a stepped cutting element is complemented by a special platform that securely holds the cut wire fragment, preventing it from injuring the patient.
Crimp (universal) pliers are actively used both in the clinic and in the dental laboratory. They are necessary for preforming rigid wire, as well as for manufacturing and adjusting various wire elements in removable appliances.
Bracket removal pliers are used for the debonding procedure — removing elements fixed with adhesive (brackets, bite platforms, band rings, buttons). Their main advantage is the ability to destroy the base pads without harming the covering tissues of the tooth. For vestibular systems, pliers with a comb-like working part are used. Depending on the dental arch segment, they are divided into:
- Straight (for the anterior segment).
- Plane-angled / angulated (for the lateral segments).
Auxiliary instruments
For positioning elements and working with ligatures, targeted instruments are used:
- Reverse-action tweezers. They feature expanding tips for a secure grip of the bracket during its application to the enamel. A thin-profile plate is located on the back side. It performs two functions: it removes excess squeezed-out adhesive and helps precisely position the bracket according to the appliance parameters and clinical situation.
- Ligature director. A double-ended instrument (with straight and angulated working parts) equipped with a guiding slot. It is needed to tuck sharp ends of the cut ligature under the arch or behind the bracket wing so they do not injure the mucosa.
- Mosquito hemostat. The most popular instrument for securing ligatures. If elastic ligatures are used, a mosquito with a hook on the working part is applied. For metal ligatures, clamps with a flat jaw surface are required.
Classification of orthodontic appliances
In orthodontic practice, several groups of appliances are distinguished that solve different tasks at different stages of treatment.
Preventive appliances
These include Hinz plates, preorthodontic trainers (elastic twin-block appliances), and fixed space maintainers. Their main indications and functions are:
- Eliminating mouth breathing, speech defects, and bad habits.
- Correcting proper tongue posture and normalizing lip closure.
- Myofunctional training, in particular strengthening the orbicularis oris muscle (m. orbicularis oris).
- Maintaining space in the dental arch in case of premature tooth loss.
Retention appliances
Used at the final stage to preserve treatment results. Their main functions are rigid fixation of dental arch forms, the position of individual teeth, and the correct intermaxillary relationship. By design, retainers can be:
- Removable plate retainers.
- Removable clear aligner/vacuum-formed retainers (including those with wire elements).
- Fixed wire retainers.
Briefly: answers to topical questions
What prenatal factors lead to the development of dentofacial anomalies?
Various exogenous prenatal factors affecting the fetus during pregnancy lead to the development of dentofacial anomalies. The following groups of factors are distinguished:
- Mechanical — trauma to the pregnant woman, tight clothing, abnormal fetal presentation, excessive amniotic fluid pressure.
- Chemical — parental alcoholism and smoking.
- Occupational — working with varnishes, paints, chemical reagents.
- Biological — diseases suffered by the pregnant woman (tuberculosis, syphilis, rubella, mumps, influenza).
- Radiation — X-ray exposure, staying in areas with elevated radiation levels.
- Psychological — stress in the first trimester of pregnancy.
What bad habits in childhood contribute to the formation of dentofacial anomalies?
Bad habits, predominantly related to sucking, lead to the formation of dentofacial anomalies in the postnatal period. These include:
- Finger sucking — a common habit in children.
- Pacifier sucking — prolonged use of a dummy/soother.
- Sucking on various objects — foreign items.
- Tongue sucking — a harmful muscular habit.
To eliminate bad habits, preventive orthodontic appliances such as Hinz plates and preorthodontic trainers are used.
What dentofacial anomalies are caused by chronic mouth breathing?
Chronic mouth breathing leads to impaired development of the jaw bones, in particular to maxillary constriction. It occurs due to insufficient airflow through the nasal passages, as well as with partial or complete atresia. Preventive orthodontic appliances are used to eliminate mouth breathing and normalize lip closure.
What endocrine disorders disrupt the formation of the dentofacial system?
The formation of the dentofacial system is disrupted by various endocrine disorders causing anomalies in jaw growth and tooth eruption timing.
| Endocrine organ pathology | Symptoms |
|---|---|
| Adrenal cortex dysfunction | Accelerated development of jaw bones, tremas |
| Cerebro-pituitary dwarfism | Underdevelopment of the facial skeleton, delayed tooth eruption |
| Hypothyroidism | Delayed eruption of deciduous and permanent teeth, micrognathia |
| Hyperthyroidism | Delayed sagittal jaw growth, premature tooth eruption |
| Adrenogenital syndrome | Macrognathia |
Which genetic factors and syndromes are associated with jaw development disorders?
Jaw development disorders may be associated with the following genetic factors and syndromes:
- Combination of parental genes that creates a disproportion in tooth and jaw sizes.
- Anomalies in jaw size and position.
- Congenital clefts of the lip, alveolar ridge, hard and soft palate.
- Dysostoses.
- Anhidrotic ectodermal dysplasia, Robin sequence, and other syndromes.
- DiGeorge syndrome, characterized by micrognathia.
- Down, Patau, Edwards, and Wolf-Hirschhorn syndromes, which belong to syndromic variants of orofacial developmental defects.
To avoid confusing cutters: Ligature cutters are for Light use (elastics, thin ligatures), Distal end cutters are for Distant use (cut off archwire ends behind the buccal tubes and hold the piece securely).
Class and exam questions
Why do distal cutters have a special holding mechanism?
The holding mechanism is necessary to secure the bitten-off segment of a rigid arch wire. This prevents the accidental entry of a sharp piece of wire into the respiratory tract or trauma to the patient's oral mucosa.
What is the specific feature of debonding pliers?
Their special pointed design (often comb-like for vestibular brackets) allows for the destruction of the adhesive layer on the base pads while completely avoiding damage to the patient's own dental hard tissues.
What tasks do preorthodontic trainers solve?
These are elastic twin-block appliances for myofunctional correction. They eliminate mouth breathing, correct tongue posture, combat speech defects, and train the maxillofacial muscles (e.g., m. orbicularis oris).
What else to study on this topic
- Biometric calculations of 3D jaw models
- Principles of working with a reverse-action tweezers during the positioning stage
- Myofunctional training of the orbicularis oris muscle
- Types of removable clear overlay retainers
- Debonding of band rings and bite turbos
Master the entire topic in the «Propaedeutics of Dentistry» course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Etiology of Dentofacial Anomalies" and 868 more pages of the subject
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 65 video lessons on the subject
Other topics in "Chapter 11. Introduction to Orthodontics"
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.