Association between occulsal interferences and bruxism in individuals aged 18-40 year of Karachi, Pakistan : a case control study

Date of Award


Document Type


Degree Name

Master of Science in Epidemiology & Biostatistics (MSc Epidemiology & Biostats)


Community Health Sciences


The increasing prevalence of bruxism is impairing the quality of life of affected individuals. The exact etiology of bruxism is unclear. The burden of bruxism is 8 — 35% globally, and 5 - 20% regionally; but burden of Bruxism in Pakistan is unknown. Studies have shown the association of some occlusal factors with bruxism in developed countries but information is lacking from Pakistani context. Objective: To determine the association between occlusal interferences and bruxism in individuals aged 18 — 40 years in Karachi-Pakistan. Methods: We conducted a matched case- control study by enrolling 106 cases of bruxism and 106 controls; matched on age (18-40 years within ±5 years). The subjects were selected from January to June 2017 at Dental clinic, AKUH, Pakistan. We diagnosed cases of bruxism on the basis of history (structured questionnaire) and dental examination (presence of tooth wear). Whereas, occlusal interferences (such as mediotrusive and laterotrusive) were diagnosed with excursive movement of the jaw using colored articulating paper. Cases were individuals with generalized attrition and history of sleep bruxism, wheareas controls did not have generalized attrition. Cases and controls were matched on age. Crude and adjusted matched odds ratio with 95% confidence intervals were reported to explore the association between bruxism and occlusal interferences. Results: The mean age of bruxers was (32 ± 7.22 SD) years and (30 ± 6.73 SD) years for non-bruxers. In our sample, males were 41.5% (44/106) and 36.5% (39/106), among bruxers and non-bruxers, respectively. Seventy one percent non-bruxers presented with moderate anxiety as compared to 69% of bruxers; assessed through internationally validated tool (HADS). We found strong association between mediotrusive occlusal interference and bruxism (aMOR=3.4; 95% CI=1.6-7.1) by adjusting all other variables in the model when matched for age. Furthermore, after adjsuting all other variables in the model, the odds of having group function occlusion among bruxers was nearly 2.7 times (aMOR=2.65; 95% CI=1.3-5.5) that of non-bruxers. However, no association between malocclusion and bruxism could be seen. Conclusions: There was a statistically significant association between occlusal interference (non-working side/ mediotrusive interference) and bruxism . Hence, it would be useful to identify and manage occlusal interferences among bruxers to an early stage to avoid dental and temporomandibular problems.

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