Oral health of seafarers in the merchant navy

Accessibility of care

Working conditions aboard may have a direct impact on oral health. On typical merchant marine cargo vessels small crews cover long distances with monotonous watches over extended periods of time at sea, alternating with short, busy periods in port. Access to oral health services during a voyage is only available in port where barriers of time constraints and cost have been described1. As a consequence, comprehensive professional oral health-care for seafarers, comprising prevention and conservation, is limited to times of home leave. Merchant navy crew may or may not be covered for oral risks by the social security and health-care systems of their home country. For treatment at home, rather than abroad in a port of call, level of cost may at least be commensurate to the income level of the seafarer. Results of a survey of 27 countries published in 1995 reports some financial support for oral treatment being available in 19 countries depending on the treatment required, age, membership in an insurance scheme etc with funds originating from ship-owners (9/19), public insurance (11/19) or private insurance (4/19)2. However, a course of oral treatment requiring a series of appointments, if it is desired during the limited time of home leave, can still be difficult to arrange3 and may not be high on the list of priorities of the seafarers4. The development of a long term relationship based on trust between patient and dentist, in which both contribute and strive for optimum oral health, remains a distant ideal under these conditions.

Within the merchant fleet, cruise vessels frequently carry very large numbers of crew, most of whom are employed in the hotel department, with working conditions more resembling work in luxury hotels ashore than work on cargo vessels. They typically spend nights at sea and enter ports almost daily for the daytime period. There are established systems for shore referral which allow access at least to emergency oral health care. There is a regular demand for oral health services by crew as reported by Dahl1, 5. A figure of 6.1 and 7.6 referrals per 1000 crew per month can be computed from his data for a population of crews of two passenger ships. An easily accessible oral service available on a cruise ship at sea at subsidised fees reported 14.5 emergency plus 42.5 routine appointments per 1000 crew per month6. Presumably, the lowered barriers of not having to leave the ship for treatment and the potentially reduced treatment cost aboard would have increased the numbers of seafarers seeking professional care.

Risk factors

Working conditions are but one factor influencing oral health. Other factors include origin of the seafarers from industrialised or developing countries with differing health-care systems, differing socio-economic and cultural backgrounds, differing educational standards and nutritional habits, different aspirations and treatment expectations which potentially impact on oral health.

Yet there are common threads for all seafarers: 24 hour operations require working in watches. On all types of vessels this influences nutritional patterns with frequent snacking3, 7 and consumption of caffeine as stimulants, frequently in form of sweetened beverages, particularly during the night. The ensuing regular intake of fermentable carbohydrates during the watch is known as a prime risk factor for oral caries. Nicotine, widely used as a stimulant and for stress relief among seafarers8, 9, is the most relevant preventable risk factor for periodontal disease. Long working hours encourage unhealthy lifestyles, lack of physical exercise and social isolation with oral health becoming a low priority. Seafaring may thus be considered a risk to oral health10, 11.

Passenger ships

A rather different group of people going to sea are cruise ship passengers. Their numbers have steadily increased with ever larger vessels carrying 6000 and more passengers plus crew. Even though the vast majority of cruises offered do not exceed one week, with frequent stops in port where oral services can be provided, a growing minority of cruise ships offer round-the-world voyages of much longer duration. Here specific concerns relating to oral health have been raised: The average age of world cruise passenger is higher, than on shorter cruises. Consequently the number and complexity of oral restorations present is higher with an increased potential for failure. 97 % of the chairside time aboard a cruise ship carrying a dentist was taken up by emergency work. The three most frequent emergency diagnoses were: defective restorations (36 %), pulpal disease (20 %), defective prosthesis and caries (both 11.5 %). Common emergency therapies provided were complex surgical-prosthodontic rehabilitation, various endodontic treatments and extractions. Per 1000 persons per month passengers required 21.6 emergency plus 2.5 routine appointments. These emergencies are not due to lack of prevention as 49 % of passengers had seen a dentist within 3 months before going to sea 12.


Oral health of military seafarers


The scientific literature on oral health issues of civilian seafarers is limited and publications are highly skewed towards industrialised countries of the north whereas important seafaring nations from the developing world, home to large numbers of seafarers, are not represented. Oral issues of other groups remote from care like offshore workers, travel/expedition medicine are only rarely considered. With the extensive resources available to military oral services it is not surprising to find a high proportion of papers on oral health at sea published by military authors with a naval background from western navies on the epidemiology of oral problems and the provision of dental treatment. Modern dentistry has historical links to military naval health services. The author of the first textbook of dentistry, “Le Chirurgien Dentiste” (1723), Pierre Fauchard (1678 – 1761), joined the French royal navy at the age of 15 under the tutelage of a naval surgeon, expert in the diseases of “dental organs” 13. A dedicated naval dental service developed alongside dentistry with the US navy employing a first dental officer as early as 187314 as senior naval chiefs were concerned about dental emergencies occurring at sea which do not only cause unnecessary suffering to the individual but may compromise the mission of the ship. To the profession it was as obvious then as it is today that a high proportion of such emergencies is preventable. The focus of naval dental services has thus been firmly on prevention of dental emergencies by screening and targeted intervention. Specialised military systems of oral health care can be studied in an attempt to convert lessons learnt for civilian use.


Risk management in seafarers

Primary Prevention

Methods to avoid occurrence of disease include selective prevention15 which addresses groups whose exposure to health risks is above average. ILO/WHO guidelines recommend education and health promotion for seafarers offered by medical practitioners who conduct pre-sea medical fitness examinations. National guidelines based on these recommendations frequently encourage the distribution of printed educational material. As an example, limiting alcohol intake, stopping smoking, modifying diet and losing weight are listed in the national guidelines of the Marshall Islands16. However, specific reference to oral health is hardly made. Oral hygiene aboard during long voyages has been described as being “totally neglected”4 and self reported tooth brushing habits were less frequent than ashore7. As early as 1965 Ugulava17 suggested possible educational preventive measures, listing brochures and flyers, articles in seafarers publications, show-models explaining periodontal disease and show cases with educational material ashore. Today electronic media including smart-phone apps could be added to this list. Wianz18 doubted the effectiveness of printed information material ashore and his emphasis on interventions at the workplace is probably still valid today. The importance of nutritional advice has been highlighted by Mausberg7 who reported the consumption of 2,400 kg of sweets on one vessel with 202 crew during a 4-months voyage. Healthy alternatives to sweets high in fermentable carbohydrates need to be available in ships’ crew shops. Any educational measures of primary prevention have to take the multitude of cultural backgrounds of crew into account. An excellent brochure for crew members “Oral Care: you are part of it....” that addresses this need is freely available from International Committee on Seafarers’ Welfare (ICSW)19 and can be downloaded from http://www.ilo.org/wcmsp5/groups/public/---ed_dialogue/---sector/documents/normativeinstrument/wcms_174794.pdf. All measures should be components of a national oral disease prevention program for seafarers20.

The more focused approach of indicated prevention involves a screening process, and aims to identify individuals who exhibit an increased risk of developing disease. In dentistry this approach is widely used in periodontics and risk assessment tools for caries have been proposed. The Periodontal Screening and Recording IndexTM (PSR) 21 is the system recommended by international bodies for the early detection of patients with periodontal disease. However, recording and interpretation of PSR and other risk assessment tools requires specialised staff (oral hygienist) and any preventive intervention on the individual level is comparatively more costly.

Secondary prevention: Pre embarkation oral examination and remedial work priorities.

Secondary prevention comprises methods to diagnose and treat oral disease in early stages before it causes pain and significant morbidity. Systematic classification of dental conditions must be followed by targeted treatment of those conditions that might deteriorate into a dental emergency. A widely used simple military screening system comprises of three classes: class I is orally fit, class II needs dental treatment but is unlikely to require emergency dental treatment within the next twelve months, class III is likely to turn into an emergency within twelve months and is thus targeted for priority treatment. All personnel not having seen a dentist for an examination for more than twelve months are assigned to class IV22. A mean time to dental emergencies for class 1 + 2 personnel of 418 days compared to 93 days in class 323 demonstrates that screening and targeted dental treatment are effectively reducing dental emergencies at sea.

However, even under near perfect conditions residual oral disease causes dental emergencies. Alexander24 and Richardson22 identified failing restorations as the most common cause for an unscheduled attendance. The US submarine force, who may be the most stringently dentally screened crews at sea, have to prepare crew members for assignments with sub-surface operations of several months duration. Deutsch published data of 240 submarine patrols with 5,187 consultations out of which only 3 % were for oral conditions. Of the dental consultations 22 % were endodontic emergencies and only 2.8 % for third-molar related emergencies, possibly due to an aggressive removal strategy prior to deployment. This converts to an emergency incidence rate of 5.0 per 100,000 person-days at sea. In contrast, we reported an emergency incidence rate of 48.3 per 100.000 person-days at sea for cruise-ship crew [re-calculated6]. The low numbers of dental emergencies still occurring in this population of submariners were frequently so severe, that the patient had to be evacuated. During the period 1991-99, 90 requests by submarines for medical assistance due to oral conditions resulted in 70 evacuations, representing 8.2 % of all evacuations25.

The International Maritime Organization’s (IMO) International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW Convention), 1978, as amended, provides that the issuance of certificates of competency is conditional upon providing satisfactory proof of having met the standards of medical fitness specified in section A-I/9 of the STCW Code. Many seafarers, therefore, have to satisfy minimum standards of medical fitness when obtaining certificates of competency.

Recommendations applicable to all seafarers have been laid down in the 2011 International Labour Organisation/International Maritime Organisation (ILO/IMO) “Guidelines on the medical examinations of seafarers”26. These guidelines include a brief section on dental health which is translated into national regulations. An example is the UK Merchant Shipping Notice 1822 (M)27 which promulgates, that a seafarer is fit to receive an unrestricted medical certificate “(a) If teeth and gums (gums alone if edentulous and with well-fitting dentures in good repair) appear to be good. No complex prosthesis OR (b) if dental check within last year, with follow-up”. It is not specified, whether a dental or any other health professional executes the “dental check”. The certificate is valid for up to two years. A medical doctor, with limited expertise in dentistry, after a only a cursory examination not normally performed under optimal conditions of lighting, without help of a suction, with no facility to blow-dry teeth, without recourse to dental radiographs is under the unenviable obligation of having to assess the current oral health status of the seafarer and its potential development in the coming two years. Most dental professionals would reject the request for such an assessment based on only scanty examination results as guesswork at best. Military screening systems require annual examinations as predictions on oral health covering more than one year are associated with increased error margins. The predictive value of oral pre-employment examinations conducted in accordance with current guidelines can only be limited.

The examiner has the option of declaring a seafarer temporarily unfit if there is visual evidence of untreated dental defects or oral disease. A practical example would be a single missing front tooth, a clear case of a highly visible dental defect or bleeding gums due to poor oral hygiene and gingivitis as an example of widespread oral disease. In practice these conditions would, in breach of the letter of the regulations, hardly lead to the refusal of a health certificate. In comparison, the military classification system would acknowledge the defect and oral disease by assigning a class II but as there is no risk of a dental emergency developing from any of these conditions the mariner would be regarded as fit for duty. The examiner can also issue a restricted certificate “limited to near coastal waters, if above criteria are not met, and type of operation will allow for access to dental care without safety critical manning issues for vessel”. There are no data available on the frequency of use of these provisions.

ILO/IMO guidelines lack detail and are not based on findings of dental science. Any revisions should be conducted with the input of dental professionals with the aim to establish standardised and audited screening regimes. Dahl1 suggested that frequent dentist referrals in port were an indication that not all pre-boarding examinations were up to the expected standard. One maritime insurer had noted values of crew claims increasing by over 60% between 2004 and 2007 from crew illness and found from the nature of the illness that many of the crew members concerned could not have been medically fit for sea service at the commencement of their employment. In some instances the crewmembers involved had only been onboard the vessel for a matter of days. Claims associated with pre -existing medical conditions in the insurers experience arise because a pre-employment medical examination was insufficiently rigorous. As the quality of examinations was observed to be variable, there were many unfit seafarers who were passed as fit for sea service, with the result that crew liability risk for the employers concerned and the insurer was adversely affected. Consequently a loss prevention programme was introduced based on enhanced pre-employment medical examinations in approved examination centers28. A similar approach to improve the quality of oral examinations is suggested. Intensive military screening systems with proven effectiveness23 are a model needing adaptation to suit civilian requirements.

Klafstad29 proposed radiographic orthopantomographic examinations and a mandatory dental certificate to be renewed at regular intervals based on the results of a study of 450 individuals showing an accumulated need for surgical interventions in more than 50 % of cases. Hahn30 presented a cost comparison, arguing for the introduction of a certificate of oral health as a condition of employment in the offshore industry, a suggestion that might be worth considering in general seafaring as well, particularly for seafarers on long voyages2. All of these proposals will require the expertise of health professionals qualified in dental public health with a clear understanding of seafaring life.

As screening systems only identify treatment needs they require mechanisms assuring delivery of treatment to correct relevant conditions. This raises the issue of accessibility and costs as relevant barriers2 to the provision of oral care which are hardly considered in the literature. Chisick31 suggested that individuals in poor oral health do not lack an understanding of their situation but lists psychological (e.g., fear of dentist), structural (e.g., queues, proximity to care) and economic (e.g., could not afford oral care) factors as potential barriers.


Dental emergencies at sea


The Danish Radiomedical Service in its 2010 annual report, which covered about 1300 consultations, stated that dental problems (8.1 %) were among the four most frequent concerns and followed after skin-symptoms (11.2 %), injuries (11.1 %) and symptoms from muscles and nerves (10.5 %)33.

A high standard of oral pre-employment examinations will eliminate a large proportion of dental emergencies occurring at sea. However, accidents do happen and some emergencies will still occur. The aims of oral first aid must be limited alleviate pain, to control infection, and to prevent permanent damage as examination and manipulation in the oral cavity are comparatively more difficult than external procedures, dental instruments are not available aboard and specific medication for oral emergencies in the medicine chest is limited to oil of cloves. There are several guides available with chapters on oral emergencies: The WHO International Medical Guide for Ships (3rd ed.) (http://www.pfst.hr/uploads/International%20Medical%20Guide%20for%20Ships.pdf) and the Guidelines for Oral Care Onboard Merchant Ships published by the International Committee on Seafarers’ Welfare (http://www.seafarershealth.org/documents/A4Guidelines-ORALCARE-LOWQ.pdf) provide basic initial guidance. As this information is naturally limited, it must be stressed that the officer providing treatment aboard should contact radio medical services for professional help. Particularly in case of spreading infection which can occur into the tissues around the jaws and then backwards or upwards towards the neck or the brain, life may be at risk. This could be the case if any of the following symptoms are present32:

■ difficulty opening the mouth

■ difficulty swallowing

■ drooling

■ difficulty breathing

■ swelling in the neck

■ pain much beyond the area of the infected tooth.

Oral health services in port

On merchant navy vessels with no oral facilities aboard the percentage of oral causes for consultations in foreign ports can be as high as 66.9 %34. Communication barriers, short turnaround times and small numbers of crew on modern cargo vessels, who are all needed for work in port, frequently limit access to oral care to the most basic emergency treatment even while the vessel is in port. In a recent survey only four countries reported providing dedicated oral health services for seafarers2. Priority arrangements in dental clinics for seafarers arranged by port agents might lower barriers to emergency oral care. Private/public partnerships could be developed to improve accessibility of oral health services in ports18, 35. Mobile dental clinics offering emergency and routine dental treatment next to vessels while alongside have been used successfully in the military in large ports36 to reduce barriers and have been suggested in the civilian sector37. Further research aimed at the interfaces between port health services, employers, health systems of home countries could help to identify financial and other barriers for routine and emergency dental treatment. Complex issues of funding oral health services for highly mobile clients in an environment with transnational stakeholders have to be explored. All components of an efficient delivery system of oral care for seafarers should be an integral part of their primary healthcare system2.

Healthcare costs may be significantly higher in ports of call than in the seafarer’s home country so that financial concerns may influence care delivery. Basic emergency treatments and pain control, which is often not more than a euphemism for dental extractions, are generally covered by the employer during voyages while any further conservative treatment may have to be paid privately. The combination of lack of time and cost of advanced treatment has been reported to lead to the loss of restorable teeth that could have been saved otherwise1.



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