3.2 Holographic Interferometry Using Generation Regime …
223
would give the possibility to detect and broaden possibilities and limits of application of this method. Moreover, the research of deformations, which occur through
functional overuse of human upper and lower jaws, was influenced by the necessity of development of this holographic methodical approach to the solution of the
mentioned problem for specialists of Surgical Dentistry Department of the Belarusian State University of advanced medical studies headed by A.S. Artyushkevich,
Doctor of medical sciences, and of Orthopedic Dentistry Department of Belarusian
State Medical University headed by Professor S.A. Naumovich, Doctor of medical
sciences. The knowledge of bone overload distribution is of great-applied importance for surgeons and orthopedic dentists while selecting and planning treatment of
patients with injuries and abnormalities of dentition.
Holographic interferometry is one of the most informative methods of physical
agent deformation detection [104]. This method was developed in collaboration with
dentists of the Ministry of Health of the Republic of Belarus and is successfully
implemented today in dentistry for studying tooth-substituting objects, plastic models
of the lower jaw and skull bones.
In our earlier studies, the experiments with overload were conducted without
taking into account the whole variety of mechanical forces caused by muscle contraction, which lift and drop the lower jaw [105–108]. Later, spatial deformations of the
lower jaw during bite and deglutition were studied. The results of the research are
of great value for the development and planning of methods of treatment in surgical
and orthopedic dentistry. In particular a special loading apparatus was developed
[109–111], which gives the possibility to imitate pressure of all front and back
mastication muscles with high accuracy, i.e., direction and absolute force of each
group of muscles. The holographic unit was used in the experiment, which gives
the possibility to record holographic interferograms with fastening of holographic
plates directly on the object, and that is why “parasitic fringes” on the interferogram
were avoided during loading of the object (Fig. 3.23). On the interferogram, it is seen
that the lines present only on the base where the object is fixed, and on the object
itself not observed shear lines are compensated. As in this case, the object was not
deformed, then there were no lines on it. As a light source, there was used radiation
of He–Ne laser LGN-215, which generates single-mode radiation with the length of
the coherency length of 20–25 cm and the wavelength of 632.8 nm. Interferogram
registration was conducted on high-resolution holographic plates PFG-03. They were
fixed in the lower jaw near a canine with glue “Cyacrine,” which provided accurate
and immovable plate fixing.
As a result, deformation fields were obtained and investigated in horizontal and
front planes on a level with alveolar process, sinciput and lower side of the jaw
(Fig. 3.24).
The qualitative estimation of holographic interferograms of the lower jaw under
different functional overloads has shown that the object experiences different deformations in the horizontal and front planes. The estimation of deformations of lower
jawbone was conducted according to the spatial distribution of the interference
fringes and their directions. The density of interference fringes depended on the
level of object deformation.
223
would give the possibility to detect and broaden possibilities and limits of application of this method. Moreover, the research of deformations, which occur through
functional overuse of human upper and lower jaws, was influenced by the necessity of development of this holographic methodical approach to the solution of the
mentioned problem for specialists of Surgical Dentistry Department of the Belarusian State University of advanced medical studies headed by A.S. Artyushkevich,
Doctor of medical sciences, and of Orthopedic Dentistry Department of Belarusian
State Medical University headed by Professor S.A. Naumovich, Doctor of medical
sciences. The knowledge of bone overload distribution is of great-applied importance for surgeons and orthopedic dentists while selecting and planning treatment of
patients with injuries and abnormalities of dentition.
Holographic interferometry is one of the most informative methods of physical
agent deformation detection [104]. This method was developed in collaboration with
dentists of the Ministry of Health of the Republic of Belarus and is successfully
implemented today in dentistry for studying tooth-substituting objects, plastic models
of the lower jaw and skull bones.
In our earlier studies, the experiments with overload were conducted without
taking into account the whole variety of mechanical forces caused by muscle contraction, which lift and drop the lower jaw [105–108]. Later, spatial deformations of the
lower jaw during bite and deglutition were studied. The results of the research are
of great value for the development and planning of methods of treatment in surgical
and orthopedic dentistry. In particular a special loading apparatus was developed
[109–111], which gives the possibility to imitate pressure of all front and back
mastication muscles with high accuracy, i.e., direction and absolute force of each
group of muscles. The holographic unit was used in the experiment, which gives
the possibility to record holographic interferograms with fastening of holographic
plates directly on the object, and that is why “parasitic fringes” on the interferogram
were avoided during loading of the object (Fig. 3.23). On the interferogram, it is seen
that the lines present only on the base where the object is fixed, and on the object
itself not observed shear lines are compensated. As in this case, the object was not
deformed, then there were no lines on it. As a light source, there was used radiation
of He–Ne laser LGN-215, which generates single-mode radiation with the length of
the coherency length of 20–25 cm and the wavelength of 632.8 nm. Interferogram
registration was conducted on high-resolution holographic plates PFG-03. They were
fixed in the lower jaw near a canine with glue “Cyacrine,” which provided accurate
and immovable plate fixing.
As a result, deformation fields were obtained and investigated in horizontal and
front planes on a level with alveolar process, sinciput and lower side of the jaw
(Fig. 3.24).
The qualitative estimation of holographic interferograms of the lower jaw under
different functional overloads has shown that the object experiences different deformations in the horizontal and front planes. The estimation of deformations of lower
jawbone was conducted according to the spatial distribution of the interference
fringes and their directions. The density of interference fringes depended on the
level of object deformation.