Journal of Oral Diseases / 2015 / Article / Tab 2

Review Article

Malocclusion Characteristics as Risk Factors for Temporomandibular Disorders: Lessons Learned from a Meta-Analysis

Table 2

Summary characteristics of included studies.

StudySampleAge (y)Diagnostic criteriaResultPotential biases and weaknesses

Fantoni et al., 2010 [9];
100% female;
156 TMD
Case = 35.4 ± 13.6; control = 35.4 ± 15.9CE; RDC/TMD Axis 1 group 1Few occlusal features show a significant predictive value for myofascial pain“All clinical examinations were performed by the same [5] trained operators”; interrater consistency was deemed sufficiently acceptable for TMD diagnosis, but there was no interrater assessment for risk factor measurements; no mention of measures to blind clinical examiners to the subjects’ case/control status; cases and controls were subject to the same inclusion criteria (which included no dental/TMD treatment in the past 6 months) and gender- and age-matched

Landi et al., 2004 [10];
100% female;
53 TMD
Mean 37.2; range 20–71CE; RDC/TMD Axis 1 group 1Occlusal features showed a low predictive value to detect muscle disorders of the stomatognathic system. Multifactorial complex pathologies, such as TMD, should be studied using multivariate statistical analyses, as univariate models may overestimate some resulting associations Single trained operator performing clinical exam; no mention of operator blinding to case/control status; presumably complete occlusal analysis was performed at the same time as case/control diagnosis; no mention of operator training to ensure proper RDC/TMD diagnosis; cases/controls subjected to the same exclusion criteria and the only comparison between cases/controls showed that controls were on average 2.6 yrs younger

Marinho et al., 2009 [11];
66% female;
51 TMD
Range 19–54CE; RDC/TMD Axis 1It was concluded that the occlusal factors have no association with temporomandibular disordersTwo operators performed clinical exams with good interrater agreements and standardized measurement methods; no mention of operator blinding; control group was roughly 1/2 female while the case group was roughly 3/4 female; cases/controls were age-matched, but other than age and gender no other characteristics were compared between cases/controls

Marklund and Wänman, 2010 [12] at baseline;
75% follow-up rate at end of 2nd year;
65% female;
dental students
Not reportedQuestionnaire + CE; case = 2-year persistent jaw muscle (JM) signs OR symptoms; classification assisted by RDC/TMD Axis 1 group 1a and group 3aAnalyses between cases and controls revealed that self-reported bruxism and crossbite, respectively, increased the risk of the incidence and duration of TMJ signs or symptoms. Female gender was a risk indicator of developing and maintaining myofascial pain. Signs of mandibular instability increased the risk of long-standing TMD signs and symptoms25% of baseline sample dropped out at follow-up and dropouts were similar to nondropouts except that greater proportion of dropouts were men; TMD defined as JM signs OR symptoms at both baseline and follow-up, so some TMD cases could have been lost from dropouts; 2 blinded and calibrated operators performed clinical examinations; women composed roughly 2/3 of total subjects and no comparison of case/control characteristics

Mohlin et al., 2004 [13];
young adults;
63% female;
62 TMD
19CE; self-created checklist evaluating muscle tenderness and function; case = symptom at 19; control = no TMD at 19 and no history of TMDOrthodontic treatment seems to be neither a major predictive nor a significant cause of TMD 55% of baseline sample dropped out at follow-up; no effort was made to assess if dropouts at follow-up affected cases and/or controls; nor was an effort made to compare the characteristics of cases/controls; orthodontic history was “assessed,” but it was unclear how this factored into the analysis or sample selection

Selaimen et al., 2007 [14];
100% female;
72 TMD
Inclusion criteria of 15–60CE; RDC/TMDThe results confirm that some occlusal factors, such as Class II malocclusion and the absence of canine guidance on lateral excursions, can be considered risk indicators for TMD, even controlling for sociodemographic confounding variables (employment, age, cigarette, and alcohol consumption)1 operator blinded to case/control status made all occlusal and TMD assessments; cases/controls subject to the same inclusion/exclusion criteria; history of orthodontic treatment was not assessed in this study and is a potential confounder; characteristics not accounted for in the inclusion/exclusion criteria (such as education, race, and employment) were accounted for in analysis with adjusted odds ratios (OR) although those adjusted ORs were not used in this meta-analysis and it would have been preferable if they were matched for during sample selection

CC = case control; CE = clinical examination.

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