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Purpose: Conical implant-abutment connections for platform switching have been recently introduced in implant systems. This study investigated the load fatigue performance of three conical abutment systems and their corresponding titanium and zirconia abutments., Materials and Methods: Regular-diameter implants of the Ankylos (AK), PrimaConnex (PC), and Straumann (ST) systems were tested with their corresponding titanium (Ti) and zirconia (Zr) abutments tightened to the recommended torque (n = 5 implant-abutment assemblies per group). A rotational load fatigue machine applied a sinusoidally varying tensile-compressive 21 N load to specimens at a 45-degree angle, producing an effective bending moment of 35 Ncm at a frequency of 10 Hz. The number of cycles to failure was recorded, with the upper limit set at 5 million cycles. Results were evaluated through analyses of variance., Results: Except for the ST Zr group, which showed no failures in four samples and one failure just below the screw head, and the AK Ti group, in which one sample was preserved without fracture, all groups experienced failure of at least one of the components, whether the abutment screw only, the abutment, and/or the implant neck. There were significant differences between systems. There was no difference between systems for the Ti abutments, and the ST group was significantly different from the AK and PC groups for the Zr abutments., Conclusions: Ti conical abutments appear to have poorer load fatigue performance compared with earlier studies of external-hexagon connections. The load fatigue performance of Zr conical abutments varied and seemed to be highly system dependent. Many of the fractures in both the Ti and Zr abutment groups occurred within the implant, and retrieval would pose a significant clinical challenge. The clinician should weigh the mechanical, biologic, and esthetic considerations before selection of any implant system, connection type, or abutment material.

Aims: To examine the relationship between depression and somatization and pain during muscle and joint palpation as well as limitations related to mandibular functioning (LRMF) in patients with temporomandibular disorders., Methods: The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) data for Axes I and II for 196 consecutive patients (56 men and 140 women) with a history of facial pain were obtained. The mean age of the predominantly Chinese patient population (83.2%) was 33.4 years (range 18 to 55 years). A computerized diagnostic system was used to collect the RDC/TMD history data. The Symptom Check List (SCL-90) depression and somatization scales were generated on-line and archived. The mean muscle pain (MP), joint pain (JP), and LRMF scores were computed with depression and somatization as main effects. Data were subjected to analysis of variance (Scheffé test) and Pearson's correlation at a significance level of .05., Results: Depression scores ranged from 4.03 to 8.16 (MP), from 0.67 to 1.03 (JP), and from 0.30 to 0.38 (LRMF); somatization scores ranged from 2.64 to 7.75 (MP), from 0.58 to 1.00 (JP), and from 0.30 to 0.41 (LRMF). Interaction effects between depression and somatization were not significant. Patients with severe depression had significantly higher MP scores than normal patients or patients with moderate depression. Patients with moderate and severe somatization had significantly higher MP scores than normal patients. LRMF scores of patients with severe somatization were significantly greater than those who were normal or suffered from moderate somatization. No significant difference in JP scores was observed for depression and somatization scales. Correlations between depression/somatization and MP, JP, and LRMF scores were significant and positive but weak; coefficients ranged from 0.15 to 0.41., Conclusion: The results suggest that depression and somatization are related to the self-report of MP. In addition, severe somatization may be associated with an increase in jaw disability.

Aims: To use the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) to investigate the physical diagnoses, psychologic distress, and psychosocial dysfunction in Asian TMD patients. The RDC/TMD Axis I and II findings were compared to those of Swedish and American TMD patients., Methods: One hundred ninety-one patients (53 male and 138 female) referred to 2 institutionalized TMD clinics in Singapore were enrolled in the study. The mean age of the predominantly Chinese population (83.2%) was 33.6 +/- 9.3 years. Data from a RDC/TMD history questionnaire and clinical examination were fed directly by patients and clinicians into a computerized diagnostic system (NUS TMDv1.1). Axis I and II findings were generated on-line, based on RDC/TMD rule engines. Data were automatically exported to SPSS for statistical analysis., Results: Group I (muscle) disorders were found in 31.4% of the patients; Group II (disc displacement) disorders were found in 15.1% and 15.7% of the patients in the left and right temporomandibular joints, respectively; and Group III (arthralgia, arthritis, and arthrosis) disorders were found in 12.6% and 13.0% of the patients in the left and right joints, respectively. Axis II assessment of psychologic status showed that 39.8% of patients experienced moderate to severe depression and 47.6% had moderate to severe nonspecific physical symptom scores. Psychosocial dysfunction was observed in only 4.2% of patients based on graded chronic pain scores., Conclusion: Axis I and II findings of Asian TMD patients were generally similar to their Swedish and American cohorts. In all 3 populations, women of child-bearing age represented the majority of patients. Muscle disorders were the most prevalent type of TMD. A substantial portion of TMD patients were depressed and experienced moderate to severe somatization.

Purpose: This study assessed multiple pain conditions and their association with psychosocial functioning, psychologic distress, and somatization in patients with temporomandibular disorders (TMD) based on RDC/TMD Axis II findings. Nonspecific pain items examined included headaches, heart/chest pain, lower back pain, nausea/abdominal pain, and muscle pain., Materials and Methods: In this study, 202 TMD patients (58 men and 144 women) referred to two TMD clinics participated. The mean age of the predominantly Chinese patient population (82%) was 32.6 years (range 13 to 65). The RDC/TMD history questionnaire was input directly into computers by patients. Graded chronic pain and SCL-90 scales were generated online and automatically archived for statistical analysis. Data were subjected to Spearman's rank-order correlation and Kruskal-Wallis and Mann-Whitney tests at a significance level of .05., Results: Of the patients, 43% were moderately to extremely distressed by headaches. The percentage of patients who were distressed by heart/chest pain (7%), lower back pain (26%), nausea/abdominal pain (17%) and soreness of muscles (22%) was lower. Of the TMD patients, 16% experienced more than three pain items. Significant and positive correlations were observed between number of pain items experienced and graded chronic pain severity, depression, and somatization. Correlation coefficients ranged from .27 to .65 for graded chronic pain scales and somatization (without pain items) scores, respectively., Conclusion: Results suggest that the number of nonspecific pain conditions reported may be a predictor of psychosocial dysfunction, depression, and somatization.