Five years’ follow-up of dental fear and anxiety, experience of dental care and oral health behaviour in Swedish preterm and full-term adolescents

Study area

This study was conducted in southern Sweden, and preterm adolescents included were born at the University Hospitals of Malmö and Lund [9].

Study population

All participants, both preterm and full-term originate from previous studies by Brogårdh-Roth 2010 [9]. In 2013 when the adolescents were 17–19 years of age, they were invited to participate in the current study. The original study sample included all adolescents born ≤32 weeks in the catchment area of Malmö-Lund from 1994 to 1996 (n = 192). With access to the Swedish Medical Birth Register, information on the children’s gestational age, birth weight, and number of siblings was collected from the Swedish National Board of Health and Welfare.

In the previous study, a control child born full-term was matched with every preterm child entering the study by age, sex, immigrant background (defined as at least one parent born outside the Nordic countries), dental clinic, and dental operator [13]. The same control children were invited to participate in the present survey.

In this study, the term preterm is used to describe children born at 32 weeks or earlier, very preterm to describe children born 29 to 32 weeks, and extremely preterm to describe children born 23 to 28 weeks.

Of the original 192 preterm adolescents, 18 declined participation for reason unknown, 21 were not reachable, and one was deceased. Further, seven preterm adolescents were unable to complete the questionnaire due to severe intellectual disabilities and were excluded. Consequently, 145 adolescents born preterm, of whom 113 very preterm and 32 extremely preterm, and 187 matched controls were included.

In the control group, 13 controls declined participation for reason unknown and 39 controls were not reachable, leaving 140 controls that agreed to participate in the present study. All the participating adolescents, except from 5 preterm and 3 controls, still lived in the same region as when aged 12–14.

Questionnaire

The questionnaire was of a self-report design and structured into the following parts. A similar questionnaire was used at the age of 12–14 years [9].

The head items in the questionnaire (Table 1) are as follows:

• Dental fear and anxiety (Children’s Fear Survey Schedule-Dental Subscale, CFSS-DS), [14]. Total scores range from 15 to 75, children/adolescents with a score ≥ 38 were categorized as having DFA according to Klingberg 1994 [15].

• Oral health behaviour was described in seven items [16, 17].

• Attitude to the dental care was described in two items: satisfaction with dental care, in general, and pain rating experienced during X-ray. The adolescent was asked to rate the pain intensity on a 100 mm Visual Analogue Scale. Rating ≥ 50 was classified as having pain in conjunction with radiographic investigations.

• Medical health included general health problems, disability, and daily medication. The following definition was used for chronic disease:

  • a disorder that is disabling, chronic or incurable, or

  • a disorder occurring at least three months during a one-year period and interfering with daily life functioning and/or needing treatment or special aids during at least three months, or

  • a disorder requiring hospitalization for at least one month or at least three periods during a one-year period [18].

The definition of general health problems was having medical problems of lesser severity or duration, e.g., allergies or minor respiratory disorders.

• School situation consisted of questions regarding satisfaction with school situation and current education, classified as three-year theoretical or practical programs [19].

Questionnaire

Main findings

In this survey, the majority of both preterm and controls rated their experience of dental care as very good or good, which is a sustaining result for the dental care system and may reflect a low overall rate of dental fear and anxiety (DFA). It appears that the transition from pediatric dentistry to adult dental care for all adolescents are well prepared. Results concerning DFA, oral health behaviour, and intake of sweets and sugary containing drinks of 17–19-year-old adolescents born preterm was comparable to that of the full-term control group. Thus, the proposed hypothesis that preterm adolescents would have higher levels of CFSS-DS scores than full-term control group is rejected. The expectation was that it would be higher in the preterm group because of the correlation to the reported increased risk for anxiety/depression during adolescence and young [6]. According to a meta-analysis, those born preterm or low birth weight were three times more likely to receive a diagnosis of a psychiatric condition, including anxiety and depression, in late childhood, adolescence and young adulthood [6]. Furthermore, different aspects of anxiety and depressive symptoms have been reported to be risk factors during early adulthood for dental fear and anxiety [20].

DFA refers to the patient’s experiences in dental care and is related to characteristics like temperamental factors and psychiatric problems as reported in preterm children [21, 22], and therefore, relevant to study. The prevalence of DFA is approximately 9% in a child population [23] and around 20% in an adult population [24]. In relation to this survey, the results showed 5.5% in the preterm group and 2.1% of the controls. In several population studies, CFSS-DS is the most frequently used measure of DFA, and the mean scores are lower than previously reported rates in adolescents [23] but fall in line with data from a study of 13–19-year-old Swedish adolescents, comparable as a reference group [25]. Also, the finding that girls had higher levels of CFSS-DS scores in both preterm and control groups is in line with previous population studies [23].

The hypotheses that adolescents born preterm are not to be considered as special needs patients in future dental care is partly rejected. Almost 50% of the adolescents reported consuming sweets and sugary drinks between meals several days per week, although in comparisons with full-term controls. The frequent consumption of soft drinks may increase the risk of caries and dental erosion [26], and it is linked to an unhealthy lifestyle in general. That more boys than girls reported a frequent intake of sweets and soft drinks several times per week is in line with a recent Swedish study of 16 year olds which named the consumption of sweets and soft drinks as a risk factor for being overweight and obese later in life, and therefore, a public health concern also from this perspective [27]. In comparison with early adolescence, the reported consumption of sweets and sugary drinks between meals several days per week in this survey had increased by about 100% in both groups. For the preterm group, with their increasingly compromized health status during adolescence, this reflects that preterm-born adolescents may be potentially at risk for oral health problems in adult life. Further, according to Sharafi et al. 2016 [12], less healthy dietary behaviours contribute to risk factors for cardiovascular disease in young adults born preterm.

The adolescent’s health status in this study increased twice from early adolescence (12–14 years) to late adolescence (17–19 years) in both the preterm and control group. These health problems included, for example, neuropsychiatric disorders, asthma, chronic lung disease, diabetes, and hearing impairments, with a prevalence of 34.4% in extremely preterm 17–19 year olds. These figures are in comparison with another Swedish study with extremely preterm 18-year-old adolescents reporting 37.6% chronic illness [28].

Dental procedures can be associated with pain, unpleasant feelings, and worry, and may result in stress and anxiety [29]. How the pain is perceived and rated relates to, for example, age, gender, and previous dental experiences [30]. Highly anxious children reported more pain than less anxious children [31]. Further, research suggests that preterm children’s experience of pain during neonatal intensive care might influence later pain sensitivity [32] and might contribute to adverse long-term physiologic and behavioural sequelae [33]. A radiographic examination is a common part of clinical dental examination and might be associated with more or less pain for everyone, even adults. The results from this survey showed that girls in both preterm and the control group rated significantly more pain than boys during radiographic exposure. This corresponds well with previous results reported by Krekmanova et al. 2009 [30]. To our knowledge, few studies have been carried out on pain sensitivity in the dental situation in preterm children. The finding that 41% of extremely adolescents and 32% of very preterm adolescents claimed pain associated with this examination suggests further exploration. The combination of common reported illness of differing severity and lower cognitive function, as frequently reported in preterm children, increases the importance of identifying pain management strategies [33], this may also include dental procedures.

Study limitations

A limitation of the study is the small number of extremely preterm participants, making comparisons within the preterm group difficult; however, this falls in line with official statistics in Sweden. Further, the longitudinal study design made it impossible to include a larger number of extremely preterm individuals.

Study strengths

This study was population-based and is a follow-up of a group surveyed from 3 to 14-years of age [9]. Consequently, the response rate of 76% in preterm and 73% in the control group is considered a satisfactory return. Another strength was the use of the same measurements and method of compiling data as in the previous study at 12–14 years. Further, the same examiner (SBR) carried out the studies on both occasions.