The role of occlusion in temporomandibular disorders (TMD) in the Northern Finland Birth Cohort (NFBC) 1966.

OBJECTIVE: To investigate the role of occlusion in temporomandibular disorders (TMDs) in the Northern Finland Birth Cohort 1966 (NFBC 1966). METHODS: Subjects (n = 1962) participated in clinical medical and dental examinations. The association between TMD signs and diagnoses with occlusal disturbances, i.e. malocclusions and occlusal interferences, was examined. Pearson's chi-square test, as expressed by odds ratios (OR) and 95% confidence intervals (CI) and logistic regression models, were used in the analysis. RESULTS: A statistically significant association was found between myalgia and lateral scissor bite and also between arthralgia and lateral deviation in the retruded contact position and intercuspal contact position (RCP-ICP) slide. Pain in the masticatory muscles was associated with negative overjet and the amount of RCP-ICP slide. DISCUSSION: Occlusal factors showed a statistically significant association with TMD. The TMD signs were associated with unstable occlusion, especially the amount and lateral deviation in RCP-ICP slide, as well as negative overjet.

Association of risk factors with temporomandibular disorders in the Northern Finland Birth Cohort 1966.

OBJECTIVE: To investigate the association between risk factors and pain-related symptoms and clinical signs of temporomandibular disorders (TMD) in Northern Finland Birth Cohort (NFBC) 1966. MATERIAL AND METHODS: A total of 1962 subjects (1050 women, 912 men) attended the follow-up study. The questionnaires included the subjects' background information concerning living conditions and general health, socioeconomic factors, and dental health. The clinical examination was performed using the modified protocol of Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) presented at the International Association for Dental Research (IADR) Conference in 2010. Cross-tabulation, a chi-square test and Fisher's exact test were used to analyze differences between groups. RESULTS: Female gender showed statistically significant association with symptoms and signs of TMD, while marital status, living conditions, and socioeconomic group showed no association. A strong association was found between self-reported health condition as well as general health problems [i.e. depression, migraine, fibromyalgia (FM), gastrointestinal diseases] and TMD pain-related symptoms and pain on palpation in the masticatory muscles and TMJs. CONCLUSION: In conclusion, general health problems and female gender had a strong association with pain-related symptoms and clinical signs of TMD. These findings are important to take into account when diagnosing and treating TMD patients. Conversely to earlier presented results, no statistically significant association was shown here between marital status, living conditions or socioeconomic group and pain-related symptoms and clinical signs of TMD.

Inter-arch digital model vs. manual cast measurements: Accuracy and reliability.

OBJECTIVES: The purpose of this study was to evaluate the accuracy and reliability of inter-arch measurements using digital dental models and conventional dental casts. METHODS: Thirty sets of dental casts with permanent dentition were examined. Manual measurements were done with a digital caliper directly on the dental casts, and digital measurements were made on 3D models by two independent examiners. Intra-class correlation coefficients (ICC), a paired sample t-test or Wilcoxon signed-rank test, and Bland-Altman plots were used to evaluate intra- and inter-examiner error and to determine the accuracy and reliability of the measurements. RESULTS: The ICC values were generally good for manual and excellent for digital measurements. The Bland-Altman plots of all the measurements showed good agreement between the manual and digital methods and excellent inter-examiner agreement using the digital method. CONCLUSION: Inter-arch occlusal measurements on digital models are accurate and reliable and are superior to manual measurements.

Prevalence of Temporomandibular Disorders in the Northern Finland Birth Cohort 1966.

AIMS: To investigate the prevalence of temporomandibular disorders (TMD) in the 46-year-old cohort subjects from the Northern Finland Birth Cohort 1966 (NFBC 1966). METHODS: Altogether, 1,962 subjects (1,050 women, 912 men) participated in a clinical medical and dental examination and responded to questionnaires in 2012 to 2013. The stomatognathic examination was performed according to a modified protocol of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Pearson's chi-square test and Fisher's exact test were used to analyze the signs of TMD between genders, and logistic regression models were used to analyze the relationship between self-reported pain associated with TMD and modified DC/TMD protocol (P < .05). RESULTS: Of the subjects available for analyses, 18.5% responded positively to the self-reported screening question for pain related to TMD. The most common signs of TMD were clicking in the temporomandibular joint (TMJ) (26.2%) and palpation pain in the masticatory muscles (11.2%). Women had signs of TMD more often than men (P < .05). The most common diagnosis was disc displacement with reduction (7.0%). Myalgia, arthralgia, disc displacement with reduction, and degenerative joint disease diagnoses were statistically significantly more common in women than in men (P < .05). The prevalence of TMD signs among the cohort subjects was 34.2%. CONCLUSION: The most common sign of TMD was clicking in the TMJ and the most common TMD diagnosis was disc displacement with reduction. The prevalence of TMD signs among the examined cohort subjects was 34.2%. TMD was diagnosed in women more often than in men. The results are comparable with other corresponding population-based studies in adults.