Facial bow: application in dentistry, difference

For effective and high-quality orthopedic and orthodontic treatment for malocclusions of various etiologies, the use of special additional devices is often required. One of them is the facebow, which has two purposes: orthopedic and orthodontic.

An orthopedic face bow is a mechanical device that serves to develop the correct trajectory of jaw movement; it is also used to create a working model of the jaw and transfer it to three-dimensional space. The use of an orthopedic facebow is an integral part of high-quality prosthetics.

An orthodontic facebow is used as an additional structure when correcting malocclusions and is often combined with other orthodontic appliances.

Use of a facebow in orthopedics

The use of a facebow in orthopedics minimizes all inaccuracies and errors in the manufacture of prostheses.

According to the principle of operation, the face arc is divided into types:

Standard (medium anatomical) - consists of a U-shaped metal plate, which is fixed on the head using an ear or nose pad, and a bite fork, which is attached to the teeth (base wax is applied to it for an impression). The standard type of arch is applied to edentulous jaws for the manufacture of removable dentures.

Kinematic - such an arch is fixed at the point of the chin and the middle of the forehead line, allows you to get very accurate results, copies the correct position of the axis when moving the jaw, and is used in the manufacture of partial elastic dentures.

For greater efficiency, an articulator is also used, which allows you to reproduce the natural movement of the lower jaw.

How to use a dental arch

Stages of using an arc:

Fastening on the patient's jaws.
Determination of individual parameters of the jaw position. In this case, the patient must bite the prosthetic “spoon” and move the lower jaw.
Removal of the device and transfer of dental parameters to the articulator (device for simulating movements of the lower jaw).

When using a facebow, the dental technician works with the best-fitted dental models that take into account all the individual trajectories of the patient's jaw movements.

Pros of use

The use of a facebow gives the patient the following advantages during prosthetics:

ease of wearing and chewing;
lack of long-term adaptation;
complete recreation of the individuality of the patient’s smile and speech;
correct distribution of food load;
maximizing the service life of the prosthesis and its supporting elements;
taking into account the slightest nuances of the location of the frontal dental group relative to the anatomy of the patient’s face.

Dentists use the following types of face bow attachment:

cervical;
head;
cervical-head.

Typically, orthodontists prescribe wearing this retainer:

after removal of crowded teeth to correct the position of molars;
for prosthetics for edentulous patients (partially or completely);
for the formation of a normal bite in children;
when maintaining the position of distant teeth after removal of the front ones;
to eliminate the mobility of chewing teeth when correcting the “smile zone”;
to prevent movement of distant teeth after their removal due to crowding.

Advantages

The use of an orthopedic facebow has a number of advantages:

Installation of dentures is faster and the time spent visiting the dentist's office is reduced.
The manufactured design is characterized by a high degree of wearing comfort.
Thanks to the precise anatomical shape of the structure, the period of adaptation to it is reduced.
Thanks to taking into account anatomical features in the manufacture of the prosthesis, chewing function is restored quickly and comfortably.
The load on the teeth is correctly distributed, which increases the life of the prosthesis, as well as supporting teeth or implants.
Good cosmetic effect and high aesthetics.

What does it represent?

This device in orthopedics and orthodontics has a different design, purpose and functionality .

An orthopedic facebow is a system designed to precisely position the relationship of the jaws in relation to each other and the center line.

The device allows you to obtain the most accurate data on the position of the jaws, which are subsequently used to form their working model and manufacture prostheses.

An orthodontic facebow is a design used to correct an abnormal bite. As a rule, a facebow is combined with a brace system.

Application of a facebow in orthodontics

The orthodontic use of a facebow is aimed at eliminating pathologies of the jaw structure and lack of space in the dentition.

The device is a curved arc consisting of two parts:

Intraoral – the inner part of the arch is attached to support rings that are fixed to the teeth.
Extraoral – fastening elements are fixed to an elastic bandage, which is fixed on the patient’s head or neck.

The following types of fixation exist:

Fastening on the head – used to correct anomalies of the upper jaw, the bandage is fixed on the back of the head.
Design with fixation on the neck – involves the elimination of defects of the lower jaw.
Combined fixation – involves the simultaneous use of the head and neck, used for severe pathology of the dentofacial apparatus.

Functions

The list of tasks implemented using the orthodontic system under consideration includes:

Restraining abnormal growth and preventing jaw abnormalities;
Maintaining the position of the lateral units of the dentition during the correction of incisors;
Restoration of the natural structure when units are crowded;
Providing sufficient free space for dystopic teeth;
Increasing the efficiency of using braces.

In addition, the functionality includes determining the position of the upper jaw using a facebow, constructing occlusal planes and identifying the location of dentition units in a static and mobile state. Solving these problems makes it possible to create precise dentures that are distinguished by comfort and aesthetics.

Advantages and disadvantages

The facebow in orthodontics is an effective tool in eliminating many anomalies in the development of occlusion.

The indisputable advantages of the face bow are:

Relatively short treatment period (up to 6 months).
Low cost due to the simplicity of the device and materials used.
The ability to use the device at night without causing psychological discomfort (the design cannot be seen by strangers).
High efficiency of the device, even in the most severe cases.

The disadvantages include the bulkiness of the design and fragile fixation, as a result of which the fastening element can jump off the support rings and injure the mucous membrane.

Kotok R.Yu.

State Institution “Dnepropetrovsk Medical Academy of the Ministry of Health of Ukraine”

USE OF
THE FACIAL BAR IN ORTHOPEDIC DENTISTRY
The joint changes, as a rule, due to improper orthopedic treatment carried out without taking into account the peculiarities of the relationship of the dentition, which leads to arthritis, arthrosis, headaches, and discomfort when opening the mouth. The art of restoring the unique correct position of each tooth in the dental arch is based on the technique of using the facebow system and a custom articulator to determine and transfer individual facial landmarks.

The facebow
is a measuring template used to transfer the position of the plaster model of the jaw into the interframe space of the articulator relative to its opening axis as the dentition is oriented relative to the skull and condyles of the mandible.

The main reasons for the need to use a face bow in the work of an orthopedic doctor are:

— construction of occlusal planes in space;

- achieving a more successful cosmetic effect;

- the possibility of a more physiological construction of dental arches, since it is possible to check and straighten the sides, axes, inclination of the teeth and cusps relative to movement in the joints, along the lateral and incisal paths.

In 1887, Hayes designed a special device - a facebow, which allows you to determine the position of the model in the articulator relative to the articular mechanism. In 1899, GBSnow improved the facebow and introduced the Snow Acme articulator.

Dalbey (1912) proposed an anatomical arch that allows one to determine the position of the lower jaw relative to the base of the skull, taking into account craniometric landmarks - the horizontal plane and the Frankfurt horizontal. Many authors believe that such an arch design, which conveys the position of the lower jaw relative to the joint, makes it possible to reduce errors in the process of fixing jaw models into the articulator.

GG Campion (1902), JB Parfitt (1903), Gysi (1910-1912) also proposed measuring facebows to transfer data to a compatible articulator.

RL Hanau (1881-1930) also used a facebow and wax registers to fix the jaw relationships to adjust the articulator. McCollum H. Stallard, C.E. Stuart and co-authors (who founded the California Gnathological Society) used a complex gnatostatic device - a head cap with a system of special measuring arcs to record patient parameters. Modern systems include anatomical, facial, measuring, recording arcs and are divided into mechanical, as well as arcs that are part of electronic devices (virtual articulators).

Depending on the articulator, the archwire technique takes into account the Camper horizontal or Frankfurt plane so that the archwire is positioned on the patient's head parallel to the selected landmark. In addition to the listed landmarks, a prerequisite for a number of facial arch designs is the location of the arc parallel to the interpupillary line. In the clinic, the Kamper horizontal plane corresponds to the nasal axis, and the Frankfurt plane corresponds to the ear orbital axis.

When installing the upper jaw model into the articulator, the arch is installed parallel to the table plane, thereby aligning the landmark with the horizontal plane. After plastering the model of the lower jaw, taking into account the bite register, they begin to adjust the articulator. During the mechanical adjustment of the articulator, the inclination of the sagittal articular path forms an angle relative to the plane of the table and the established landmark. If the scale is oriented relative to the Camper horizontal, the line of closure of the jaw models cast in the articulator is approximately parallel to the plane of the table.

In articulators that take into account the Frankfurt plane, the plaster model of the upper jaw is tilted forward, the occlusal plane forms an angle with the horizontal plane that opens distally. Determining the basic parameters using a facebow requires its correct location. Teeth impressions obtained on a bite fork. Measuring stencils allow you to take into account the position of the head. However, the installation of the model is carried out taking into account one reference point: the Camper plane.

As a rule, a facebow consists of three parts: the arch itself (located on the patient’s head), a fork for obtaining impressions of the teeth of the upper jaw (models of the upper jaw) and a device that connects these parts, and with the help of a special lock that fixes the original position of the upper jaw.

Along with the position of the upper jaw, the face bow transfers the patient’s usual head position to the articulator, since the position of the molars of the upper jaw determines the position of the head. Thus, strict requirements are imposed on the position of the patient during registration, the materials used to obtain impressions, the quality of impressions of the upper jaw teeth, and the quality of impressions and jaw models.

The teeth marks on the bite fork should not be deep. They are obtained sequentially, starting from the front incisors, without strong pressure on the impression material located on the fork. Plastics and composites are also used for prints.

Methods of application

We will describe three ways to use a facebow:

Method 1.

In a mid-anatomical joint transfer, the approximate center of rotation of the condyle must first be found. It is located on a line connecting the outer corner of the eye with the apex of the tragus of the ear, approximately 13 mm. forward from the external auditory meatus. If you place the articular stop along these landmarks, then the error in finding the true axis of rotation of the mandibular condyle will be no more than 2 mm.

Method 2

. During mid-anatomical transfer from the external auditory canal, the articular support is first replaced with an ear support in the form of an ear olive. On the facebow and on the articulator, respectively, sockets must be made for mounting the arc, both from the joint and from the external auditory canal. The distance between these sockets should be calibrated at 13mm as described above.

Method 3

. The bite fork on the kinematic facebow is first attached to the lower dentition. Then, while the patient moves the jaw back and forth, opens and closes it; The dentist notes the movements of the knuckle point because the kinematic facebow knuckles have pointed pointers and their movement can be tracked more accurately.

Installation of a facebow along the external auditory canal is convenient and quick, which is why today it is the most commonly accepted method. The bite fork on the mid-anatomical arch is attached to the upper dentition, thus, the mid-anatomical transfer is the simplest approximate transfer of the position of the upper jaw and the transfer of the axis of rotation of the lower jaw to the articulator.

the Amann Girrbach
1 facebow

Material is applied to the bite fork to obtain an impression of the occlusal surface of the upper jaw teeth.

A bite fork is inserted into the oral cavity and pressed against the teeth of the upper jaw. The bite fork is held until the material hardens completely.

Installation of a facebow - ear pads are inserted into the external auditory canals.

The facebow frame is connected to the bite fork using an adapter device.

Fixation on the bridge of the nose.

Clamp the position of the adapter device and the bite fork with the clamp.

Installing the facebow orbital pointer

Fixation on the bridge of the nose.

Clamp the position of the adapter device and the bite fork with the clamp.

Installing the facebow orbital pointer

The universal clamp connecting the spoon and the face bow is released.

The bite fork is removed from the mouth along with the transition device and the face bow is removed.

10.

The position of the spoon is transferred and the spoon is fitted using a universal portable table 11. The next stage is the position of the spoon is transferred and plastered using a portable table into the mounting laboratory articulator.

12.

In the laboratory, the model of the upper jaw is plastered on a tray, in spatial position to the upper base of the laboratory articulator.

What does the patient receive when the face bow is used adequately by a specialist:

— prosthetic work is more convenient and comfortable;

— prostheses do not require a long period of adaptation;

— there is a more effective restoration of the function of chewing and speech;

— the correct distribution of the load on the teeth is restored, which increases the service life of any orthopedic structure;

— the harmonious spatial arrangement of the frontal group of teeth relative to the position of the patient’s eyes, nose, lips and other anatomical features is realized.

Recently, many companies have been producing lightweight arch designs and fixing devices that allow the face bow to be positioned without any effort on the part of the doctor. The use of a face bow in the work of a dentist is a necessity, without which it is impossible to achieve satisfactory results in the work.

Literature:

1. Statovskaya, E.E. Application of a facebow when working with articulators / E.E. Statovskaya // LAB. 2008. - No. 1. - P. 51-53.

2. Clinical methods for diagnosing functional disorders of the dental system, / I.Yu. Lebedenko, S.D. Arutyunov, M.M. Antonik et al.//M., 2006.-111 p. 3. Khvatova, V.A. Occlusion and articulation in the practice of orthopedists and dental technicians. Part 6 / V.A. Khvatova // New in dentistry. 2001. - No. 1. -S. 43-56. 4. Bragin, E.A. Individual articulator / E.A. Bragin, A.A. Dolgalev // Current issues in orthopedic dentistry: collection of articles. scientific works Voronezh, 2000.-P.20-22. 5. Schwartz; A.D: Axioms of biomechanics. Some principles of orthopedic dentistry / A.D. Schwartz // New in dentistry. 2000. -No. 3. - P. 24-40.

What you need to know when using a facebow

For high effectiveness of using the design, a patient who is prescribed a face bow should follow a number of recommendations. They consist of observing the following rules:

Daily use of the device should not exceed ten hours.
To eliminate pain and discomfort that may occur when moving teeth into the correct position, it is recommended to use painkillers,
Before fixing the arch, it is necessary to carry out high-quality hygienic treatment of the structure and the oral cavity.
The facebow should only be worn when at rest.
During the period of use of the arc, the gums may become inflamed. In this case, to eliminate the causes of swelling and redness of the gums due to excessive pressure of the arc on the tissue, it is necessary to visit a dentist,
If you use the arc while sleeping, you need to make sure that it is securely fastened.

Despite the bulkiness of the design, the face bow, when used correctly, is an effective orthodontic device.

Recommendations for patients using orthodontic facial lugs

To achieve the desired treatment results throughout the entire period of wearing a face bow, patients must adhere to a number of recommendations and rules:

do not wear the device for longer than the time recommended by your doctor;
If pain and discomfort occurs from moving teeth, take prescribed painkillers;
do not forget about oral hygiene before fixing the device;
use the arc while in a calm state. Physical activity with the arch installed is unacceptable;
securely fasten the arch while sleeping.