Awareness of Clenching and Underweight are Risk Factors for Onset of Crowding in Young Adults: A Prospective 3-Year Cohort Study

Abstract

Bruxism is a parafunctional activity that can seriously affect quality of life. Although bruxism induces many problems in the oral and maxillofacial area, whether it contributes to the onset of malocclusion remains unclear. The purpose of this prospective cohort study was to investigate the association between the onset of malocclusion and awareness of clenching during the daytime in young adults. Among 1,092 Okayama University students who underwent normal occlusion at baseline, we analysed 238 who had undergone a dental examination and had complete data after 3 years (2013–2016). We also performed subgroup analysis to focus on the association between awake bruxism and the onset of crowding (n = 216). Odds ratios (ORs) were calculated using multivariate logistic regression analyses. The incidences of malocclusion and crowding were 53.8% and 44.5%, respectively. In multivariate logistic regression, awareness of clenching was a risk factor for crowding (OR: 3.63; 95% confidence interval [CI]: 1.08–12.17). Moreover, underweight (body mass index < 18.5 kg/m2) was related to the onset of malocclusion (OR: 2.34; 95%CI: 1.11–4.92) and crowding (OR: 2.52, 95%CI: 1.25–5.76). These results suggest that awareness of clenching during the daytime and underweight are risk factors for the onset of crowding in young adults.

Is there association between dental malocclusion and bruxism? A systematic review and meta‐analysis

“…Ten studies 5,[9][10][11][12][13][14][15][16]21 met the inclusion criteria and so were included in this systematic review, including eight of which were cross-sectional, 9,11,12,[14][15][16]20,21 one of which was a cohort study 10 and one that was a case-control study 13 (Figure 1).…”

“…Five studies 11,13,14,16,21 were conducted in Brazil; two were performed in Japan 5,10 ; and one each was completed in Turkey,…”

“…Mexico and Sweden, respectively. 9,12,15 Study participants ranged from children (aged two years old) to adults, and the setting of the research varied from universities 5,10,12 to healthcare units, 11 dental clinics 9,21 and schools. [13][14][15][16] The diagnosis of bruxism was made solely through the use of questionnaires designed according to the American Academy of Sleep Medicine guidelines 22 in nine of the studies, 5,[9][10][11][12]14,16,21 while one study completed the diagnosis of bruxism through clinical evaluation only, 15 and one study did such through both approaches.…”

“…9,12,15 Study participants ranged from children (aged two years old) to adults, and the setting of the research varied from universities 5,10,12 to healthcare units, 11 dental clinics 9,21 and schools. [13][14][15][16] The diagnosis of bruxism was made solely through the use of questionnaires designed according to the American Academy of Sleep Medicine guidelines 22 in nine of the studies, 5,[9][10][11][12]14,16,21 while one study completed the diagnosis of bruxism through clinical evaluation only, 15 and one study did such through both approaches. 13 Dental malocclusion was classified predominantly using Angle's classification scheme 23 or a modified version of the Index of Orthodontic Treatment Need, 5,10,24 while some authors created their own classification 11,13,16,21 and others used previous studies as reference material.…”

“…7,8 Nonetheless, some recent studies have evaluated this association and reported significant results. 5,[9][10][11] Vieira-Andrade et al 11 and Kataoka et al 5 performed cross-sectional studies in children and young adults, respectively, and reported a significant association existed between bruxism and crowding. Also, Toyama et al in 2019 10 observed the same results in a cohort study.…”