This was a longitudinal prospective census-type study that assessed the oral health related quality of life and stress in a military population submitted to a training cruise over six months. Additionally, the association between OHRQL and stress was investigated.
This study was performed during the annual midshipmen training cruise (MTC) on the Brazilian training ship Brasil (U27) in 2019. MTC lasted six months, making 17 port calls in 14 countries. The crew comprised of 31 officers, 228 non-commissioned officers, sailors and civilians, and 227 cadets, known as midshipmen. Upon completion of MTC, the midshipmen receive their commission as officer and serve aboard ships and other military organizations in Brazil.
As an institutional exigence regarding oral condition, all the military personnel who participate in MTC must meet parameters of health, like satisfactory aesthetics, healthy dental articulation, healthy soft tissues, and healthy and treated teeth. Partial or total dental prosthesis are also admitted. Some conditions are considered unsatisfactory including the following: acute or chronic processes in the oral cavity, decay without treatment or with insufficient treatment, unsatisfactory restorations and prosthesis, infections, cysts, tumors, dental absences in the lip battery without aesthetic and functional rehabilitation, and impacted teeth that cause painful chewing.
Before MTC, all military staff submit to an exam of panoramic radiograph exam to identify who needs complex procedures, such as prosthesis, complex extraction and endodontics treatment. These individuals are referred to specific dentists who treats their condition and make them eligible to do MTC.
On a scheduled work day, the military personnel aboard were invited to attend a meeting in the auditorium, where they were given instructions and objectives of the study before it began. Irrespective of age, sex, function or personnel aboard, they were invited to participate in the survey, being assured of confidentiality of the information provided. When they agreed to enroll, the informed consent was signed. The option to refuse to participate was a clear option.
This study was approved by Marcílio Dias Navy Hospital Research Ethics Committee, in Rio de Janeiro, Brazil, protocol 10751419.8.0000.5256/2019, and followed the ethical standards established by the Declaration of Helsinki.
Demographic and social data
The demographic and social data obtained were related to sex (male; female), personnel aboard (crew; cadets), age (in years), and education (high school; higher education). The age was divided into four age ranges: 20 to 29; 30 to 39; 40 to 49; and over 50 years old.
One examiner applied two anonymous questionnaires: A) perceived stress scale, and B) oral health impact profile.
A) Perceived stress scale
The perceived stress scale (PSS-14) measures someone`s stress level based on stressful incidents and the ability to face them on an individual level. PSS-14 comprises of 14 questions with responses varying from 0 to 4 for each item, and ranging from never, seldom, sometimes, fairly often, and very often, respectively, based on their occurrence one month before the survey. PSS-14 scores are obtained by reversing the scores on positive items, for example 0 = 4, 1 = 3, 2 = 2, 3 = 1, and 4 = 0, and then summing across all 14 items. Items 4, 5, 6, 7, 9, 10, and 13 are the positively stated items (10, 11). The scores ranged from 0 to 56, 28 being the operational cutoff value (10, 12). Participants were labeled as “stressed” when scoring upper bound and as “non stressed” when scoring less than 28.
B) Oral health impact profile
The oral health impact profile (OHIP-14) intends to measure the physical, psychological, and social impact of oral conditions one month before the survey and are composed of 14 items that assess seven different dimensions (functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap). Each item has a set of possible answers rated on a 5-point Likert scale (4 = always, 3 = frequently, 2 = sometimes, 1 = seldom, and 0 = never). OHIP-14 scores can range from 0 to 56 and are calculated by summing the ordinal values for the 14 items (13).
PSS-14 and OHIP-14 were applied at two moments: a) baseline, two days before the annual MTC got started; and b) follow-up, the last day of the mission, in July and December of 2019, respectively.
Descriptive statistics were performed for the demographic and social data.
After the questionnaires were completed, the means of PSS-14 and OHIP-14 at baseline and follow-up were obtained.
The personnel aboard were separated into two groups: crew and cadets, and it was verified if the mean of each questionnaire was different between these groups at baseline and follow-up.
Scores for each item of OHIP-14 were compared for the whole military population and separately for the crew and cadets group, at baseline and follow-up, to identify which of them had changed the most during MTC.
The sum of PSS-14 was categorized as “non stressed” (sum < 28) or “stressed” (sum ≥ 28). Then, it was investigated whether the categorized variables of PSS-14 were different between both groups at baseline and follow-up.
Crude and multivariable Poisson regression with robust covariance was used to test the association between personnel aboard, age range, education, and PSS-14 with OHIP-14 scores at baseline and follow-up.
Statistical differences between groups were evaluated using the Chi-Square test for categorical variables and the T-test or the Mann-Whitney U test for continuous variables with a significance level of 5%. All data processing and analyses were performed using the software SPSS version 21.0 (“Statistical Package for the Social Sciences”, SPSS Inc., Chicago, USA).