SRM Journal of Research in Dental Sciences

LETTER TO EDITOR
Year
: 2016  |  Volume : 7  |  Issue : 3  |  Page : 205--207

Maxillofacial aeronautics: An evolving entity


Ankita Bohra1, Manoj Vengal2, Neelkant Patil3, Vipul Udawat1,  
1 Department of Oral Medicine and Radiology, Vyas Dental College and Hospital, Jodhpur, Rajasthan, India
2 Department of Oral Medicine and Radiology, KMCT College, Kozhikode, Kerala, India
3 Department of Oral Medicine and Radiology, Rajasthan Dental College, Jaipur, Rajasthan, India

Correspondence Address:
Ankita Bohra
Department of Oral Medicine and Radiology, Vyas Dental College and Hospital, Jodhpur - 341 008, Rajasthan
India




How to cite this article:
Bohra A, Vengal M, Patil N, Udawat V. Maxillofacial aeronautics: An evolving entity.SRM J Res Dent Sci 2016;7:205-207


How to cite this URL:
Bohra A, Vengal M, Patil N, Udawat V. Maxillofacial aeronautics: An evolving entity. SRM J Res Dent Sci [serial online] 2016 [cited 2021 Mar 6 ];7:205-207
Available from: https://www.srmjrds.in/text.asp?2016/7/3/205/188804


Full Text

Sir,

The scope of dentistry is very vast and needs to be highlighted by our dental members to increase the awareness of this field in the general public. Many new dental fields are introduced in the past few years, of which one new branch is aeronautical dentistry. With the foray of man in outer space, oral health of cosmonauts is an important perspective. Aeronautical dentistry deals with the health concerns of the cosmonauts in the aeronautical environment.

 What Is Aero Dentistry



The field of dentistry is vast than it has been considered so far. A special field of dentistry which has been introduced for the aeronautical environment is known as aeronautical dentistry. The term was introduced by Rai in 2007.[1] Outer space is full of challenges either in terms of physical troubles or in terms of psychological. The human body is acclimatized according to the earth's environment, and microgravity experiences are severe and hazardous for the overall health of astronauts. Numerous physiological changes include neurological disturbances, cardiovascular problems, motion sickness, disorientation, reduction in muscle mass and bone mineral density, and alteration in circadian rhythm of the body.[1],[2] Only a few studies are published on the effect of microgravity on oral health. Recent reports suggest the prevalence of periodontitis, dental caries, bone loss, pain and numbness of teeth and oral tissues, salivary duct calculi, and cancer in microgravity conditions, along with certain radiographic changes in weightlessness condition.[3] Aeronautical dentistry deals with all these changes in outer space environment for dental research purpose. A review enlightens the less-discussed field of dentistry which will play a very beneficial role in protecting dental health of cosmonauts.[4]

 Effect on Oral Health and Periodontium



Bone loss results after each space flight leading to osteoporotic changes and teeth mobility. Normal oral mucosal flora gets altered with the changes in the salivary flow rate and alterations in the quality of saliva that occur after a long space mission. The 8-hydroxydeoxyguanosine levels were increased in saliva in microgravity environments as compared to normal; it may be due to increase in oxidative stress.[5] Salivary glucosyltransferase B levels were increased in space as compared to earth and indicated that caries prevalence is more during microgravity. Obstruction in sublingual and submandibular opening duct regions, abnormal facial expression, loss of sensation of pain and temperature, decreased tongue, xerostomia, change in taste, edema of face, and reduced mandibular movements in microgravity environment were observed due to fluid shift mechanism [Figure 1]. Due to reduced salivary flow rate, the incidence of caries increases with teeth more prone toward periapical and periodontal pathologies.[6]{Figure 1}

 Effect on Skeletal System and Temporomandibular Joint



Bones are dynamic, living tissues which undergo repeated resorption and deposition under the effect of mechanical stress and strain. In the absence of gravity, less mechanical strain is applied to bones and joints, thus resulting in bone loss. Due to bone loss, bone mineral density decreases which results in weak bones and more prone to fractures. All processes start from bone formation, and new bone deposition to bone mineralization decreases or stops during the phase of weightlessness. Disfigurement of circadian rhythm, physiological and psychological stress occurs in microgravity that affects temporomandibular joint (TMJ). Hypothalamus prepares the human body to withstand stressful conditions causing autonomic nervous system activation resulting in increased muscle tonicity. Stress causes reduction of bone mineral density of the temporomandibular region.[7] In case of microgravity, there is a reduction in overall muscle mass, thus causing an insufficient increase in muscle tonicity during stressful period. The effect of stress directly affects the temporomandibular architecture along with an overall reduction in bone mineral density of the complete body. Abnormal facial expression, loss of sensation of pain and temperature, and decreased tongue and mandibular movements in simulation microgravity environment were observed due to fluid shift mechanism. Thus, the effect on TMJ experienced by cosmonauts is more psychological than physiological. In longer duration space visits, circulating parathormone concentration also reduces which, in turn, reduces Vitamin D metabolism and, thus, resulting in overall Vitamin D deficiency. The effect on disorientation of complete body homeostasis affects combined toward disarrangement of TMJ function.[8] The problem increases with longer missions and frequent visits [Figure 2].{Figure 2}

 Carcinogenic Potential



Cosmic radiations have the capacity to induce malignant changes, thus resulting in precancerous changes in the oral mucosa. Carcinogenic potential varies from person to person depending on multiple factors such as heredity, self-immune response, gender, and presence of hazardous habits. High-speed atomic particles cause tearing of DNA of cells resulting in cellular damage. Damaged DNA undergoes mutations resulting in carcinogenic changes. A dose of 1 Sv is enough to increase the risk of malignant potential in tissues by many times. Normal daily radiation exposure in humans ranges between 1 and 10 mSv.[9],[10]

 Conclusion



Aeronautical dentistry is an upcoming branch which needs to be flourished by proper understanding of the extra terrestrial environmental conditions and their respective effect on oral microflora. This will help in management and needful treatment of the complications regarding microgravity on oral health. Further knowledge of exobiological condition is required to protect us from cosmologic health hazards.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Rai B. Aeronautic dentistry: A new specialized branch and its curriculum guidelines. Internet J Dent Sci 2007;5:69-72.
2Azen EA. Genetic protein polymorphisms in human saliva: An interpretive review. Biochem Genet 1978;16:79-99.
3Carlson DM, Zhou J, Wright PS. Molecular structure and transcriptional regulation of the salivary gland proline-rich protein multigene families. Prog Nucleic Acid Res Mol Biol 1991;41:1-22.
4Oppenheim FG, Hay DI, Franzblau C. Proline-rich proteins from human parotid saliva. I. Isolation and partial characterization. Biochemistry 1971;10:4233-8.
5Oppenheim FG, Xu T, McMillian FM, Levitz SM, Diamond RD, Offner GD, et al. Histatins, a novel family of histidine-rich proteins in human parotid secretion. Isolation, characterization, primary structure, and fungistatic effects on Candida albicans. J Biol Chem 1988;263:7472-7.
6Offner GD, Troxler RF. Heterogeneity of high-molecular-weight human salivary mucins. Adv Dent Res 2000;14:69-75.
7Denny P, Hagen FK, Hardt M, Liao L, Yan W, Arellanno M, et al. The proteomes of human parotid and submandibular/sublingual gland salivas collected as the ductal secretions. J Proteome Res 2008;7:1994-2006.
8Bandhakavi S, Stone MD, Onsongo G, Van Riper SK, Griffin TJ. A dynamic range compression and three-dimensional peptide fractionation analysis platform expands proteome coverage and the diagnostic potential of whole saliva. J Proteome Res 2008;8:5590-8600.
9Lima DP, Diniz DG, Moimaz SA, Sumida DH, Okamoto AC. Saliva: Reflection of the body. Int J Infect Dis 2010;14:e184-8.
10Miller CS, Foley JD, Bailey AL, Campell CL, Humphries RL, Christodoulides N, et al. Current developments in salivary diagnostics. Biomark Med 2010;4:171-89.