International Journal of Contemporary Dental and Medical Reviews (2015), Article ID 350115, 4 Pages

REVIEW ARTICLE

Aviation dentistry: New horizon, new challenge Lalitagauri Mandke, Shagun Garg

Department of Conservative Dentistry & Endodontics, DY Patil University School of Dentistry, Navi Mumbai, Maharashtra, India

Correspondence: Abstract Dr. Lalitagauri Mandke, Department After the innovations in aviation at the beginning of the 20th century, many in-fl ight of Conservative Dentistry and pathologic and physiologic conditions were reported. Changing atmospheric , Endodontics, DY Patil University School especially if it is rapid, can cause discomfort and damage to the oral cavities and maxillofacial of Dentistry, Nerul, Navi Mumbai, Maharashtra, India. Phone: +91 9820966259. areas unless the pressure within these cavities containing gas is able to equilibrate with the E-mail: [email protected] external air pressure. Out of these conditions - ( due to gas entrapment) and (pressure induced tooth fracture, restoration and tooth fracture) was Received 26 January 2015; most frequently seen to occur. Due to partial pressurization of aeroplanes’ cabins and Accepted 04 March 2015 improvement in dental techniques and oral health awareness, prevalence of fl ight-related oral manifestations has declined. It is important for the dental practitioners to be familiar doi: 10.15713/ins.ijcdmr. 55 with these facts and not to neglect dental education with respect to aviation. Aircrew patients as well as air passengers often make it challenging for the dentist to treat several How to cite the article: fl ight-related conditions. Correct diagnosis should be made before these conditions lead Lalitagauri Mandke, Shagun Garg, to serious complications. With thorough practice and experience, the aircrew are now “Aviation dentistry: New horizon, new challenge,” Int J Contemp Dent Med able to avoid, or treat, these pressure related problems. Rev, vol. 2015, Article ID: 350115, 2015. Keywords: Aviation dentistry, barodontalgia, barotrauma doi: 10.15713/ins.ijcdmr. 55

Introduction Many human body organs viz. facial sinuses, lungs, stomach, middle ear contain gas. Gas also may exist in conditions It is a known fact that at higher altitudes there is a reduction such as dental abscess, beneath a leaky restoration or in in air density and air pressure. The decrease in pressure is that gastro-intestinal problems.[2] at 18,000 feet, air pressure is half that of that at sea level and at A person in fl ight is subjected to reduced air pressure. 33,000 feet. It is a quarter as seen at sea level.[1] This reduction in Here, the gas present within the body tends to expand. In cases air pressure has a many negative eff ect on aviators. where the gas can communicate with the external environment When an aircraft is at a high altitude, (e.g. nose, mouth etc.) the pressure gets dissipated. However will be too low but inside aircraft pressure is maintained such when there is no outlet for the gas, the pressure builds up, leading that it is comfortable for crew and passengers. The pressure and [6] regulation in aircraft is done by means of aircycle to pain, discomfort and impaired organ function. machines and outfl ow valves.[2] Similarly in the oral cavity, the gas pockets present in dental During fl ight, the aircrew is responsible for the lives of the aircrew abscesses, periodontitis, deep carious lesions and deep, unlined members and passengers for completing the fl ight successfully. Any restorations can lead to severe pain. Thus, extreme altitude [7] problem within the fl ight could lead to failures in the fl ight’s safety.[3] changes can lead to (barodontalgia). Dental practice and education are evolving with technological Due to infrequent meals, the aircrew members may suff er [8] advancements. The focus is now on prevention. With the some gastrointestinal problems too. Experienced aircrew advanced expansion in the airlines industry with air travel now are aware of these pressure related problems and are able [5] being the chief mode of transport, special attention must be paid to manage them. The dental surgeons should be made aware toward the crew members and air travellers.[4] of these in-fl ight so they are better equipped to treat air Aviation dentistry primarily deals with the oral and dental travellers. health status of the aviators. It deals with the diagnosis, principles of prevention and treatment, disorders or conditions which are Barotrauma related to the oral cavity and maxillofacial area and their impact on those who travel in such an environment where there is change Barotrauma refers to physical damage or trauma to body in pressure than that of the normal atmospheric pressure.[5] tissues caused by rapid or extreme changes in air pressure. It

1 Aviation dentistry Mandke and Garg is commonly seen in , in air travellers, hyperbaric Barotrauma of Dental Origin therapy or exposure to shock waves from an explosion.[9] Barodontalgia It is a tissue injury seen due to changes in pressure, wherein the gas compresses or expands, which is present in various hard or Barodontalgia is an oral (dental or non-dental) pain caused by soft body structures. In cases where there is increased pressure a change in barometric pressure in an otherwise asymptomatic outside the body, this pressure is equally transmitted through organ. Gases are confi ned within the closed spaces due to the entire body. Those organs or tissues, which contain mainly which it is unable to contract to adjust the internal pressure. fl uids, do not get compressed. Organs such as lungs, sinuses, Individuals experience pain, which may be sharp or squeezing middle ear, which contain gases, get aff ected. The gas present in nature. Whether the pain occurs during ascent or descent in these organs expands or gets compressed according to the depends entirely on the related pathology.[5] In general, pain on decrease or increase in the outside pressure. This causes pain, ascent is related to vital pulp disease (i.e. pulpitis) and pain on numbness and damage to the involved tissue.[5,10] descent to pulp necrosis or facial barotrauma. Pain related to periapical disease can appear during ascent as well as descent.[9] The pain usually ceases when returning to onset level or ground Barotrauma of Non-dental Origin atmospheric level, but can last longer if caused by periapical Barotrauma can commonly aff ect the ears, which are also called disease or facial barotrauma. Barodontalgia is a symptom aerootitis or barotitis.[11] It is observed that plane landing leads to rather than a pathologic condition itself. In most cases, it is an [18] extreme pain in the ear (the pressure change can create a vacuum exacerbation of pre-existing subclinical oral disease. in the middle ear that pulls the eardrum inward causing pain), Several suggestions to explain the pathogenesis of [19] dizziness (vertigo), bleeding or fl uid coming from the ear (due barodontalgia were given. Strohaver in 1972 advocated to a ruptured eardrum) and ultimately hearing loss.[12,13] the diff erentiation of into direct and indirect types. In direct Barotrauma incidence is also observed in conditions such as barodontalgia, reduced atmospheric pressure leads to direct respiratory tract infections, sinusitis or blockage of Eustachian eff ect on the aff ected tooth, whereas in the indirect type, dental tubes. In all the above conditions, there is congestion or blocking pain is due to the stimulation of the superior alveolar nerves of free air-fl ow between organs or spaces.[14] at the time of maxillary barosinusitis. Direct barodontalgia is Among all types of barotrauma, pulmonary barotrauma is characterised by moderate to severe pain, which usually develops most dangerous. In this condition, there is pain and fullness in during take-off . It is well localized and the patient can identify the chest, shortness of breath, radiating pain to neck and shoulders involved tooth whereas indirect barodontalgia is a dull, poorly and a feeling of light headedness. More severe conditions may defi ned pain that generally involves the posterior maxillary teeth lead to coma, seizure or stroke. Deep at the time of and develops during landing. ascent may help in preventing pulmonary barotrauma.[15] Exposure to altered atmospheric pressure is obviously a Barosinusitis is another condition associated with higher signifi cant factor resulting in pain production in barodontalgia altitudes. Normally, there is no air pressure diff erence between with disease of the pulp as one of the probable cause. Ferjentsik [20] the external environment and the . However, and Aker stated that normal pulp tissue would not produce at high altitudes, there usually develops a negative air pressure pressure associated pain, regardless of whether restorations [21] diff erence between the two. This leads to acute/chronic or caries were present. However, Hodges has reported that infl ammation of the paranasal sinuses (mainly the ). dental pain could be produced in apparently healthy teeth when This condition is termed as barosinusitis, sinus barotrauma, the atmospheric pressure was increased. aerosinusitis or sinus squeeze.[14] Aerosinusitis can also lead to Experimental research indicates that barodontalgia dental pain (hence called indirect barodontalgia).[16] may depend on an increased pulpal pressure induced by Vacuum created inside the sinus may also seem to cause pressure variations in the permeability of the dentinal tubules. damage to the ethmoid cell mucosa which may trigger the ethmoid Barodontalgia may also be due to expansion of trapped air nerves (branches of the ophthalmic branch of the trigeminal bubbles under a restoration or against dentin that activates the [22] nerve that innervate the mucosa on the inner surface of the sinus). pain receptors. It could also be due to stimulation of nerve This may lead to orbital and/or peri-orbital headache.[17] endings in an infl pulp or stimulation of nociceptors in the To prevent the above risks from occurring, it’s better with referred pain to the teeth. to postpone the fl ight for people suff ering from a cold or Barometric tooth explosion congestion. Using a decongestant could help in some cases. To relieve the pressure during take-off and landing sucking candy, It was reported that teeth with pre-existing leaked restoration chewing gum, yawning or breathing with the mouth open can be or remaining/recurrent caries lesions underneath restoration benefi cial.Usage of fi ltered earplugs can help to slowly equalize led to tooth explosion when exposed to changes in atmospheric the air pressure against the eardrum. Since one does not swallow pressure.[23] This condition is known as Barometric tooth enough during sleep, keeping awake during descent can also explosion, barodontocrexis or odontocrexis. Although the prove helpful. destructive potential of arrested or remaining carious lesions

2 Mandke and Garg Aviation dentistry in daily life is minimal, it seems that these lesions may not be as Periodontal considerations asymptomatic or minimal in a pressure-changed environment. Decrease in salivation and dryness of mouth are few of the risk [24] Calder and Ramsey reported that all the damaged teeth either factors responsible for the development of caries lesions. Dryness had poor quality of amalgam restorations with unfavorable of the mouth can be due to breathing of dry compressed gases clearance between the tooth and the amalgam or secondary in the aircraft.[32] There is increased risk of periodontal diseases caries under the restoration. Odontocrexis can potentially because of xerostomia. lead to severe pain, swallowing of the tooth fragments or even their aspiration.[25] Oral surgery Patients should be advised not to fl y while having provisional When maxillary teeth are extracted, the dental surgeons should restorations or temporary cement in their mouth. Leaky or faulty always rule out the existence of an oroantral communication restorations should be diagnosed and replaced. Carious lesions as it can lead to sinusitis when exposed to a pressure should also be excavated and restored. Placement of cuspal changing environment.[33] coverage crowns could also be a preventive measure. Prevention Prosthetic considerations Caries excavations and restorations should be completed before Lyons et al. studied the retention of crowns to extracted teeth airtravel. Leaky restorations should be replaced. During the in environmental pressure changing conditions. The crowns restoration of a carious tooth, a thorough examination of the fl oor cemented with glass-ionomer cement or zinc phosphate cement of the cavity should be done to rule out any penetration leading had reduced retention with the tooth. Crowns cemented with to the pulp chamber. In such cases a protective cavity liner should resin cement did not have reduced retention.[26] This can be be applied (e.g. glass-ionomer cement). During multi-visit due to porosities incorporated at the time of manipulation endodontic treatment, the temporary restoration must be placed of zinc phosphate cement and glass-ionomer cement. These properly. When oroantral communication is diagnosed; referral microporosities expand and contract upon pressure changes to an oral surgeon for its closure is indicated.[9] leading to weakened cement.[25] Microleakage was also Cuspal coverage crowns could also be a preventive measure. detected in zinc phosphate and glass-ionomer cements after Resin cements are preferred for cementation, as they give better pressure changes, whereas no microleakage was detected in retention. During fl ight, chewing gum or candy will increase resin cement.[27] salivation and prevent dryness in the mouth. Reduced barometric pressure can reduce the retention of [28] full removable dentures (especially maxillary dentures). Conclusion Retention by osteointegrated dental implants is the best for edentulous fl iers.[4] There has been a tremendous increase in air travellers viz. pilots, aircrew personnel, air passengers, fl ight attendants and leisure Restorative dentistry pilots. Special precautions must be taken during endodontic, restorative, prosthodontic and oral maxillo facial surgical treatments Pure oxygen inhalation may cause corrosion of dental amalgam for the aircrew patients to prevent any kind of in-fl ight incapabilities restorations in cases due to increased percentage of oxygen.[29] leading to serious issues. Aviation dentistry is an emerging science, Diff erential thermal contraction in cases of low temperature of a which has been much neglected.With air travel gaining popularity, high altitude environment is seen of amalgam materials as compared [30] the in-fl ight dental hazards cannot be ignored anymore. The dental with tooth hard tissue. Harvey reported that cold temperature is clinicians should take an initiative to raise awareness levels and unlikely the dominant mechanism underlying dental fracture. sensitize the air travellers about this issue. The need of the hour is to Excessive occlusal was also a factor in dental restoration promote diagnostic tools and treatment guidelines to the aviation dislodgement. Sognnaes, suggested that clenching or grinding of industry to ensure wellness of air travellers. teeth was a causative factor for restorative failure.[18]

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