Journal of

Oral Rehabilitation

Journal of Oral Rehabilitation 2014 41; 148--154

Normative values for the oro-facial Esthetic Scale in Sweden P. LARSSON*†, M. T. JOHN‡, K. NILNER§ & T. LIST‡ †

*Centre for Oral Rehabilitation, Norrk€oping,

Department of Orofacial Pain and Jawfunction, Faculty of Odontology, Malm€o University, Malm€o, Sweden, ‡Division of Epidemiology and

Community Health and Department of Diagnostic and Biological Sciences, University of Minnesota, Minneapolis, MN, USA and §Department of Prosthetic Dentistry, Faculty of Odontology, Malm€o University, Malm€o, Sweden

SUMMARY This study reports the findings and challenges of the assessment of oro-facial aesthetics in the Swedish general population and the development of normative values for the selfreporting Orofacial Esthetic Scale (OES). In a Swedish national sample of 1406 adult subjects (response rate: 47%), OES decile norms were established. The influence of sociodemographics (gender, age, and education), oral health status and general health status on OES scores was analysed. Mean  standard deviation of OES scores was 50
3  15
6 units (0, worst score; 70, best score); 5 OES units) for subjects with excellent/very good

Introduction Modern dentistry changed dramatically in recent years. Traditional focal points were function and biology (1, 2). While these have not been abandoned, patients’ aesthetic concerns have become important and now play an integral part in their oral health (3). Oral conditions that affect oro-facial aesthetics are common. In a national survey in the UK, 15% of the respondents were dissatisfied with their dental appearance (4). The impact of impaired oro-facial aesthetics extends beyond the masticatory system. Davis et al. (5), 1998 found patient’s self-esteem and quality of life to be related to dentofacial aesthetics and successful tooth restorations. The need to assess oro-facial aesthetics in a standardised way led to the development of the Orofacial © 2013 John Wiley & Sons Ltd

versus good to poor oral or general health status; ii) small (2 units), but statistically significant for gender (P = 0
01) and two age groups (P = 0
02), and (iii) absent for subjects with college versus no college education (P = 0
31) or with and without dentures (P = 0
90). To estimate normative values for a self-reporting health status, instrument is considered an important step in standardisation, and the developed norms provide a frame of reference in the general population to interpret the Orofacial Esthetic Scale scores. KEYWORDS: oro-facial aesthetics, oral health, norms, normative values, appearance, aesthetics Accepted for publication 25 November 2013

Esthetic Scale (OES) (6, 7), an eight-item questionnaire designed to provide an overview of aesthetic concerns in adult prosthodontic patients. Assessing how orofacial aesthetics is perceived in the general population, specifically on a national level, would be the next step in a strategy to assess OES in different settings and populations. John et al. (8), 2012 showed in a previous study sufficient reliability and validity of OES scores in the Swedish general population and suggested that the OES instrument could be extended to the general population, an important target population. Because oro-facial aesthetics is considered a dimension of perceived oral health/oral health-related quality of life (9), such an assessment would describe a key element of population oral health, and hence, an important factor for demand/need of oral health services. doi: 10.1111/joor.12121

SELF-REPORTED AESTHETICS IN THE GENERAL POPULATION In addition, such development of normative values for OES is an essential part of instrument development and provides a frame of reference for interpreting normal scale values. However, the sensitive nature of oro-facial aesthetics challenges its assessment in the general population where incentives to participate are lower than in patient populations seeking treatment. Therefore, the assessment of oro-facial aesthetics in the general population may be prone to non-response of unknown magnitude. The aims of this study were (i) to determine the self-reported oro-facial aesthetics in the adult general Swedish population and (ii) to derive normative values for the Orofacial Esthetic Scale.

Materials and methods Setting A nationally representative random sample (N = 3000; Fig. 1) of Swedish-speaking subjects, 18 years or older and drawn from the national population register (Folkbokf€ oringen), were approached for the survey. SIFO Research International monitored the postal survey. The questionnaire was sent to each individual by mail. If they did not respond within the time period, two reminders were sent, one with the questionnaire. Forty-seven per cent (N = 1406) of the eligible subjects responded. The Regional Ethics Review Board at Link€ oping University Hospital approved the study protocol. All patients gave an informed consent and received no monetary compensation.

Random sample of Swedish general population N = 3000 Subjects with data N = 1406 >2 items left blank N = 71 ≤2 items left blank N = 1335 >2 items NA N = 174 >2 combined blanks/NA N=2

≤2 items NA N = 1161 ≤2 missing (blanks/NA) N = 1159 (Final number)

Fig. 1. Intended and actual study subjects. © 2013 John Wiley & Sons Ltd

Data collection Subjects reported in the survey the presence of tooth loss and oral pains and how they perceived the impact of these conditions in a questionnaire. As part of this questionnaire, the Swedish version of the self-reporting instrument OES (6, 7) was included. The OES contains eight items, which asks patients for their opinion of the appearance of their face, mouth, teeth and tooth replacements. Patients responded using a 0–10 numeric rating scale, where zero represents very dissatisfied and 10 represents very satisfied. Subjects who do not want to respond to an item can mark the option ‘not applicable’. Orofacial Esthetic Scale items refer to seven aesthetic components (face, Q1; facial profile, Q2; mouth, Q3; rows of teeth, Q4; tooth shape/form, Q5; tooth colour, Q6; gum, Q7). These seven items are combined into a summary score ranging from 0 (worst score – patient is very dissatisfied with all aesthetic items) to 70 (best score – patient is very satisfied with all aesthetic items). An eighth OES item characterises the patient’s global assessment of oro-facial aesthetics (Q8).

Data analysis Outcome variables of the study were 1 The OES summary score (sum of Q1–Q7), which describes the oro-facial aesthetic construct as a whole, 2 The seven OES items, each of which describe one component of the construct and 3 The patient’s global assessment (Q8) of oro-facial aesthetics. Influence of sociodemographic, oral health and general health status on OES scores was investigated: 1 Three demographic variables: (i) age (two categories based on the median), (ii) gender and (iii) a dichotomous education variable (elementary or high school/gymnasium versus university/college education). 2 Two indicators of self-reported oral health: (i) denture status – the presence of fixed or removable dentures (versus no dentures, i.e., subjects had only their own teeth) was considered a core indicator of physical oral health, and (ii) the dichotomous global assessment of oral health status (poor, moderate or good versus very good or excellent) was considered a summary measure of perceived oral health.

149

150

P . L A R S S O N et al. 3 Similar to the assessment of perceived oral health, general health status was assessed with a global assessment using the same five response categories (poor, moderate or good versus very good or excellent) combined into the dichotomous variable. Orofacial Esthetic Scale score differences between sociodemographic, oral health and general health status groups were tested using t-tests or median tests. Norms were calculated as deciles (10 percentiles) for the OES score with 95% confidence intervals. A typical OES value in the Swedish general population would be the median or the 5th decile. The influence of sociodemography or denture status on OES scores determined whether the norms would be stratified or not. The estimates and confidence intervals for the Swedish population were computed with the statistical software STATA (*Release 10.0 StataCorp. 2007;). Missing OES information Six of eight possible OES item responses were defined as sufficient to measure the construct oro-facial aesthetic, that is, to compute a summary score. Consequently, subjects who submitted non-responses to more than two OES items (i.e. more than 25% missing information) were withdrawn from analyses. Missing items were of two types: (i) items left blank and (ii) items with a response of ‘not applicable’. Per these criteria, 247 subjects were excluded, and OES data from 1159 (39%) subjects were analysed (Fig. 1). Missing OES data were imputed using median imputation, that is, if a person has a missing value, it gets the median of his/her non-missing items values imputed to fill the missing value. We analysed non-response in various ways. First, we compared total non-response with item nonresponse by comparing sociodemographic data of the study subjects who responded with data on (i) all subjects in the original study sample and (ii) the Swedish general population. Second, we analysed levels of item non-response by classifying number of blank and NA responses into three categories: major >2; minor = 2–1; no = 0 items. Major item non-response classification led to exclusion of the subject. Combining blank and NA responses created this grouping:

*Stata Statistical Software, College Station, TX, USA.

1 >2 blank and >0 NA items (subjects with non-sufficient OES because of blank items) 2 ≤2 blank and >2 NA items (subjects with non-sufficient OES because of NA items) 3 ≤2 blank and ≤2 NA items (subjects with sufficient OES but some blank and some NA items) 4 ≤2 blank and 0 NA items (subjects with sufficient OES and no blank and no NA items) 5 0 blank and 0 NA items (subjects with sufficient OES and no blank and no NA items) In these groups of subjects, we compared dichotomised sociodemographic status variables and physical oral health status. We compared item and OES score severity in the last three groups, those with sufficient OES information.

Results The 1406 subjects who responded to the survey were on average 49
2  17
4 years old (range 18–85), 56% were women, and 37% had a university education. These sociodemographic characteristics were similar to those of the Swedish general population per 2009 data published by the Statistics Sweden (Statistiska Centralbyr an) (10). Frequency of OES summary scores and norms Mean and median OES summary scores were similar, 50
3 and 53 OES points, respectively (Table 2). Table 1 presents OES summary score norms in deciles. 10% of the subjects with the lowest scores had 29 units or less. When the influence of sociodemography, oral health and general health status was investigated,

Table 1. Orofacial Esthetic Scale summary score norms Percentile

OES summary score

95% confidence interval

10 20 30 40 50 60 70 80 90

29 35 43 48 53 57 62 65 70

27–30 35–37 41–44 46–49 51–54 56–58 61–62 64–66 69–70

© 2013 John Wiley & Sons Ltd

SELF-REPORTED AESTHETICS IN THE GENERAL POPULATION OES means and medians did not differ unambiguously across sociodemographic or denture status (Table 2) – differences between means or medians in subgroups were four OES points or less. But OES scores did differ substantially in categories of perceived oral health or general health status – differences in means or medians were between 5
5 and 13 OES points, with the most pronounced differences occurring in perceived oral health status categories. Results of t-tests or median tests were consistent. Orofacial Esthetic Scale differences were significant for age (P = 0
02), self-reported oral health (P < 0
01) and self-reported general health status groups (P < 0
01). No significant difference was found for university/college education (P = 0
31) and denture status (P = 0
90). A mean OES score difference of 2
4 points between genders was significant (P = 0
01), while a median difference of 2 units was not. Because the influence of sociodemography and physical oral health status on OES scores was small, we decided not to stratify norms (Table 2). Only four subjects (2 NA items

≤2 blank items & ≤2 NA items

≤2 blank items & no NA items

No blank items & no NA items

N = 1594

N = 71

N = 174

N = 34

N = 29

N = 1098

0
55 0
44

0
66 0
66

0
62 0
59

0
60 0
68

0
56 0
71

0
38

0
36

0
18

0
26

0
20

0
33

0
32

0
50

0
42

0
48

7
60 7
50 7
20 6
90 7
20 6
30 7
60 7
50

7
10 6
90 6
60 6
70 6
50 6
30 6
90 7
20

6
00 8
30 6
80 6
30 6
80 5
10 7
90 6
60 48
8

6
80 7
30 5
40 6
50 7
10 6
00 7
80 8
20 48
4

8
30 7
00 2
00 4
50 6
30 7
80 6
00 6
40 50
3

Subjects with non-sufficient OES information because of blank items; subjects with non-sufficient OES information because of NA items; subjects have sufficient OES but some blank and some NA items; subjects have sufficient OES but some blank and no NA items; subjects have sufficient OES no blank and no NA items. © 2013 John Wiley & Sons Ltd

SELF-REPORTED AESTHETICS IN THE GENERAL POPULATION from these findings will serve as a framework for OES score interpretation. The assessment of oro-facial aesthetics in the adult general population via a postal survey was challenging due to total survey nonresponse and item non-response. This situation provides a considerable potential for bias. Prevalence of impaired oro-facial aesthetics Taking complete satisfaction with oro-facial aesthetics as preference, we expected that the majority of the sample would report a negative impact across the various OES items. Indeed, only 10% of the subjects were very satisfied with all aspects of oro-facial aesthetics. These results, that subjects perceive their oro-facial aesthetics as less than ideal, are in line with other studies using self-reports of dental appearance (3, 4). An Israelian study (1) found that 37% of 407 adults were dissatisfied with their dental appearance, and Xiaoxian et al. (2007) reported a high, but slightly lower figure with 24% of 873 adults in Florida. In a national study, the same number of Germans reported that they felt uncomfortable with their appearance in the last month, and slightly