Nankali’s masticatory force systematization categorizes the locations of the forces on different part of mandible/maxilla, which are important in designing a prosthetic and implant treatment in dentistry.

Masticatory muscles

The

muscles of mastication There are four classical muscles of mastication. During mastication, three muscles of mastication (''musculi masticatorii'') are responsible for adduction of the jaw, and one (the lateral pterygoid) helps to abduct it. All four move the jaw late ...

or masticatory muscles are: :a)

masseter In human anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is particularly powerful in herbivores to facilitate chewing of plant matter. The most obvious muscle of mastication is the masseter muscle, since it ...

, :b)

temporalis In anatomy, the temporalis muscle, also known as the temporal muscle, is one of the muscles of mastication (chewing). It is a broad, fan-shaped convergent muscle on each side of the head that fills the temporal fossa, superior to the zygomatic a ...

, :c) medial pterygoid, :d) superior belly of the lateral pterygoid, :e) anterior digastrics, :f)

geniohyoid The geniohyoid muscle is a narrow muscle situated superior to the medial border of the mylohyoid muscle. It is named for its passage from the chin ("genio-" is a standard prefix for "chin") to the hyoid bone. Structure It arises from the infe ...

, :g) mylohyoid :h) inferior belly of the lateral pterygoid.

Measuring masticatory force

The masticatory force initially was measured by Dr. Bleck. Bleck used a gnathodynamometer and also found out the close relation between periodontal tissue and masticatory force. Dr. Morill worked more deeply on the relationship between masticatory muscles and pain signals from the periodontal tissue in different ways. Dr. Shreder, using local

anaesthesia Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), am ...

(to ignore the periodontal response) measured the maximum possible force of the masticatory system and discovered the differences in the produced force, which was approximately doubled. The periodontal system controls automatically the measure of mastication force in this process and the jaw elevator muscles develop the main forces used in mastication. Dr. Weber worked out that 1 cm² cross section surface area of any masticatory muscle can produce approximately 10 kg force. The following average surfaces were found:

- 8 cm²,

- 7.5 cm², and medial pterygoid - 4 cm² which makes a total of 19.5cm². However, this force in some people is measured up to 3900N in combination. The force generated during routine mastication like having carrots or meat is about 70-150N although in some people with specific conditions it may reach up to 500-700N.; Dr. Ali Nankali continued the masticatory force study and observed a number of mastication acts by individuals using computer. The monitored results of this investigation illustrated constant changes in the amount of masticatory force during mastication due to the characteristic and size of the mouthful. He also studied the relation between mechanical and bio-physiological movements of the masticatory system which shows that creating the masticatory force is directly depended to the surface area and its orientation and therefore he suggested the masticatory force systematization. According to this systematization, the masticatory force is divided in two main groups, physiological and pathological groups. The physiological masticatory force by itself is divided into three subgroups according to their localizations, anterior, general (covering the entire arch) and posterior section of the arch. The posterior group is also divided into two other groups; unilateral and bilateral.Nankali A. (2002) "Investigation of strength properties of the hard materials of the tooth roots". Ministry of Public Health of Ukraine / ''Ukrainian Scientific Medical Youth Journal'', Quarterly Scientific Journal No. 33 -, p74-76 This systematization proves that the condition of producing a maximum masticatory force by a person is using the general subgroup of this systematization.

History

The systematization of the masticatory force distribution was designed by Nankali in the National Medical University at the

orthopedic Orthopedic surgery or orthopedics ( alternatively spelt orthopaedics), is the branch of surgery concerned with conditions involving the musculoskeletal system. Orthopedic surgeons use both surgical and nonsurgical means to treat musculoskeletal ...

and

implant Implant can refer to: Medicine *Implant (medicine), or specifically: ** Brain implant ** Breast implant **Buttock implant **Cochlear implant **Contraceptive implant **Dental implant ** Fetal tissue implant **Implantable cardioverter-defibrillator ...

stomatology An oral medicine or stomatology doctor (or stomatologist) has received additional specialized training and experience in the diagnosis and management of oral mucosal abnormalities (growths, ulcers, infection, allergies, immune-mediated and autoim ...

department, which was verified (October 1999) by the Scientific Board of National Medical University (O.O. Bogomolets) and international patent organization (УДК; 616.314-76-77:616.314.11-74:678.029.46:612.311) in Kiev. This systematization was presented for the first time at the 55th Medical Science Conference of Students & Young Scientists in 2000, organized by the Ukraine Health Ministry and the National Medical University known as O.O. Bogomolets, and Society Science Students known as O.O. Kisilia. The result of presentation in "Young Scientists and Students / Scientific Medical Seminar in 1999" was published.

References

{{Prosthodontology Prosthodontology