Association between gingival bleeding and gingival enlargement and oral health-related quality of life (OHRQoL) of subjects under fixed orthodontic treatment: a cross-sectional study

Quality of life (QoL) is conceived as an eminently human notion that is a reflection of the degree of satisfaction with one’s family and social life [1]. It presupposes the ability to perform a cultural synthesis of many aspects of life that reflect the knowledge, experience and values of individuals and groups over the ages; thus, it is a social construct having the cultural relativity of social elements in its model of comfort and well-being [1].

Oral health-related quality of life (OHRQoL) is defined by self-reports specifically pertaining to oral health, capturing both the functional, social and psychological impacts of oral disease [2]. Oral epidemiology has used indices to assess the self-reporting of OHRQoL issues as adjuncts to clinical examinations, thereby documenting the full impact of oral disorders. There is a range of instruments designed for these aims [3]. The OHIP₁₄ is one of these instruments; it has been widely used in several cross-sectional and longitudinal studies including adolescents [4] and young adult [5] populations under orthodontic treatment. It is divided in to seven subscales, grouping functional limitation, physical pain, psychological discomfort, physical and psychological disabilities and handicap [3]. The questionnaire was developed in Australia [6], but further studies confirmed its validity and reliability in Brazilian population [7].

Periodontal disease is usually documented by therapist-centered surrogate endpoints such as bleeding on probing (BOP), probing depth PD and clinical attachment level (CAL). However, patient-centered measures have recently begun to be explored [1]. These methods have attempted to measure the impact of periodontal status on patients’ lives, and have shown that periodontal disease does have an impact on patients’ quality of life [8–13] and recently it has been demonstrated by a systematic review that periodontal treatment can moderately improve OHRQoL [14]. Thus, the identification of this impact may provide an opportunity for promoting more effective and suitable actions to be employed as complements to normative criteria [15].

Clinical studies have indicated that orthodontic treatment may be associated with deterioration in periodontal health [16–18]. However, the majority of studies have concluded that overall gingival alterations are transient with no permanent damage to periodontal supporting tissues [19–22].

To the best of our knowledge, there are no studies evaluating the OHRQoL impact of periodontal conditions on individuals receiving orthodontic therapy. This study aimed to evaluate the independent associations between OHRQoL and gingival enlargement and gingival bleeding.

This cross-sectional survey examined a group of subjects, 14 to 30 years of age, who were receiving orthodontic treatment in an orthodontic graduate clinic in Santa Maria, a city in southern Brazil. The study protocol was reviewed and approved by the Committee of Ethics in Research of the Franciscan University Center (protocol n^o 063.2010.2). Subjects who agreed to participate signed an informed consent form. Patients diagnosed with oral pathological conditions (i.e. gingivitis, periodontitis, active caries, semiological lesions, …) were advised to seek consultation and treatment.

The present study demonstrated that gingival enlargement is associated with OHRQoL. Regarding factors associated with the impact of oral conditions on OHRQoL, the most frequently reported variables in the literature were caries and socioeconomic status [29]. When the impact of periodontal disease on OHRQoL is evaluated, clinical attachment loss or probing pocket depth have been used to verify this association, but without taking marginal gingival alterations into consideration [12, 13, 30]. In the present study, anterior gingival enlargement was independently associated with overall OHIP-14 scores.

In the last years, the OHIP-14 instrument has been used to verify associations between OHRQoL and periodontal conditions. Our study revealed a relatively small variation among OHIP-14 scores. On the other hand, previous studies presented larger variation. Araújo et al. ² demonstrated a variation in overall OHIP-14 scores, ranging between 36–56 points in 61.2% of subjects with periodontal disease, defining CAL as the endpoint. Meanwhile, our study found a maximum value of 8 points. Ng and Leung⁷ demonstrated that subjects from a Chinese population, with full-mouth mean CAL above 3 mm, scored significantly higher on the impact of oral health on their OHRQoL in the overall OHIP-14and several subscales. Similar results were found by Bernabé and Marcenes¹¹, who considered individuals to have periodontal disease to be those having at least two proximal sites with CAL ≥ 4 mm, and at least one proximal site with PD ≥ 4 mm. Differences related to the criteria for defining periodontal disease may explain the differences with the results from our study, related to the level of impact of periodontal disease on OHRQoL. In the present study, we did not use PD or CAL as independent variables due to the low mean values of PD and CAL (2.06 mm and 1.60 mm, respectively). We therefore used anterior gingival enlargement to report periodontal alterations, in order to evaluate whether a gingival aesthetic aspect would impact patients’ OHRQoL. Moreover, to the best of our knowledge, evidence evaluating the impact of gingival enlargement associated with orthodontic treatment on OHRQoL is nonexistent. From this perspective, the present study gives new information.

Gingival appearance is one of the components of the harmony of the smile, which is seen as one of the most important physical characteristics of the development of self-image and self-esteem. It expresses feelings of joy, success, sensuality, affection, and reveals self-confidence and kindness. People who are satisfied with their smile appear to be more self-confident and have higher self-esteem than those who are dissatisfied [31]. Subjects whose dental and gingival aspects are not in agreement with social patterns are most commonly affected with an unpleasant appearance [31–33]. Evidence shows that gingival enlargement (GE) is associated with aesthetic impairment and, in more severe cases, with phonetic alterations and masticatory problems [34, 35]. Thus, higher levels of age may show increased emotional and social problems, which could be reflected in the association with higher means of overall OHIP-14. GE associated with orthodontic treatment is a hypertrophic form of gingivitis. The exact mechanism for the development of GE is not completely understood, but probably involves increased production by fibroblasts of amorphous ground substances with a high level of glycosaminoglycans. Increases in the mRNA expression of type I collagen and up-regulation of the keratinocyte growth factor receptor could play important role in the excessive proliferation of epithelial cells and the development of GE [36]. In some studies, poor oral hygiene enhanced GE [37, 38], while other clinical studies concluded that overall gingival changes during orthodontic treatment are transient with no permanent damage to the periodontal supporting tissues [19, 22]. Another hypothesis that may partly explain our results is the age range of the subjects, which ranged from 14 to 30 years. In this age group, aesthetic appearance seems to be more valued than by those of younger or older ages [39].

According to the dichotomization of “important impact” (scores of “fairly often” or “very often” in one or more of the OHIP-14 items) of oral health status on OHRQoL, 17.2% of subjects reported important impact in the psychological discomfort domain (been self-conscious and/or felt tense), while 11.8% and 5.1% reported important impact in the functional limitation and psychological disability domains (found difficult to relax and/or felt embarrassed), respectively. The analysis of the psychological discomfort and psychological disability domains revealed that subjects with higher means of anterior gingival enlargement had a greater level of concern and embarrassment than did subjects with lower means of anterior gingival enlargement. However, we found that most of the responses to the OHIP-14 domains showed little impact (“never”, “hardly ever” or “occasionally”) of oral conditions on OHRQoL. Another study demonstrated that the most frequent responses to OHIP-14 were “fairly often” and “very often”, for both the relaxation dimension and the embarrassment felt by patients with periodontal disease [8]. It has to be highlighted that subjects participating in that study had clinical diagnosis of periodontitis, while most subjects of our study had only gingivitis. It is to be expected to find a higher mean impact on OHRQoL in subjects with periodontitis because it is associated with a wide range of clinical signs and symptoms such as bleeding, tooth mobility, receding gums, bad breadth and toothache, which may have considerable impact on the daily life of subjects with more severe periodontal disease [10, 13, 30].

Variables related to socio-demographic characteristics, like ethnicity and household income, were demonstrated to influence subjects’ perception of OHRQoL. It has been established that individuals from different socioeconomic backgrounds are exposed to different risk factors that affect oral health and, consequently, perceive the impact of oral health on OHRQoL in different ways [40]. Moreover, individuals with lower socioeconomic status are subjected to material deprivation which could influence their engaging in riskier behaviors, resulting in more severe impacts on their OHRQoL [41].

The present study did not find differences on overall OHIP-14 scores, after adjustment, between the genders. This result disagrees with a previous study that reported higher impact of oral health on OHRQoL in women as compared to men [42]. This result could be explained by one of the following hypotheses: first, in subjects with orthodontic appliances, females present a similar concern with aesthetic-related issues than men. Second, the lack of extreme differences related to socioeconomic status in our sample may have influenced the results, since self-reported health-related quality-of-life between males and females may be influenced by sociodemographic and socioeconomic status [40]. Third, our study may have lacked adequate power to detect differences between men and women.

The results of the present study corroborate several studies demonstrating that socioeconomic gradients affect the prevalence of oral health problems [41]. Non-white subjects present a higher gradient of oral disease, and this fact cannot be theoretically related to socioeconomic disparities. Thus, compared to their white counterparts, non-whites have a greater likelihood of perceiving a higher impact of oral health on their OHRQoL [43].

Our findings showed that severe malocclusion was found to be associated with higher overall OHIP-14 scores. DAI was used to measure the degree of malocclusion and it’s aorthodontic index based on socially defined aesthetic standards. It is useful in epidemiological surveys to identify the need for orthodontic treatment, and also as a screening device to determine priority for subsidized orthodontic treatment. Cut-off points for the determination of severe malocclusion were previously reported [26]. Patients with severe malocclusions may report various oral health impacts that affect their well-being in many ways [44].

Data analysis showed that excess body weight is associated with OHRQoL. One interpretation of these results is that there is a body standard for attractiveness in a larger cultural context. Accordingly, subjects constantly confronted with the media’s slender and beautiful renderings may aspire to an ideal quite impossible for most of them to attain. Not achieving these ideals, they end up with low self-esteem [40].

It’s well established that socioeconomic status and other dental clinical variables have a negative impact on OHRQoL [3, 45]. Therefore, the associations between gingival bleeding and gingival enlargement with OHRQoL were assessed taking into account the possible confounding effects of these variables. Studies assessing the association between gingival enlargement and its impact in OHRQoL in orthodontic subjects, using multiple regression analyses controlled for other sociodemographic and clinical variables which may act as confounders, are nonexistent. In addition, Poisson regression with robust variance was used in order to provide PR estimates, which are easier to interpret than odds ratios. This study had a cross-sectional design, which hypothesizes relations between the outcome and predictor variables, without establishing causal relationships. This is a limitation of this study. However, conclusions from cross-sectional studies are important for identifying indicators to be included in longitudinal or even, experimental studies [46]. The present study involved 330 orthodontic patients attending a private orthodontic specialist training program. This convenience sample limited the extent to which these findings can be generalized to a larger population.

Anterior gingival enlargement does impact on OHRQoL and it is associated to sociodemographic characteristics in young subjects under orthodontic fixed treatment. Thus, it is possible that prevention and/or treatment of gingival enlargement may improve the OHRQoL of orthodontic patients. However, further studies are required to understand this issue better.