Load fatigue performance of conical implant-abutment connections.

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.

Relationships between depression/somatization and self-reports of pain and disability.

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.

Depressive symptoms in Asian TMD patients and their association with non-specific physical symptoms reporting.

BACKGROUND: The expression of depression in Asian temporomandibular disorder (TMD) patients may differ from that of their Caucasian counterparts. This study examined the prevalence of depressive symptoms and their association with non-specific physical symptoms (NPSs) reporting in Asian patients. METHODS: Two hundred and fifty-five Asian TMD patients (68 males; 187 females) with a mean age of 33.0 years were selected for this study. Research diagnostic criteria (RDC)/TMD history questionnaire was input directly into computers by patients using the NUS TMDv.1.1 software. Symptom Checklist 90 (SCL-90) depression and NPS scales were generated online and automatically archived for statistical analysis. Data were subjected to ANOVA/Scheffe's test and Pearson's correlation at significance level 0.05 and 0.01, respectively. RESULTS: 43.1 and 50.6% of the patients scored moderate-to-severe on the depression and NPS scales, respectively. The percentage of patients with diffuse physical symptoms remained high (45.5%), even after pain items were excluded from the computation. NPS scores ranged from 0.34 to 1.64, while depression scores ranged from 0.27 to 1.21. A significant and positive correlation (r = 0.74) was observed between depression and NPS scores. CONCLUSIONS: The prevalence of depressive symptoms and NPSs was lower in Asian TMD patients. Psychological distress experienced by female Asian TMD patients was comparable to their male counterparts. Results also suggest that depressive symptomatology is associated with the reporting of multiple NPSs.

Prevalence of temporomandibular disorder subtypes, psychologic distress, and psychosocial dysfunction in Asian patients.

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.

Multiple pains and psychosocial functioning/psychologic distress in TMD patients.

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.

Clinical TMD, pain-related disability and psychological status of TMD patients.

This study investigated the clinical temporomandibular disorders (TMD), pain-related disability and psychological status of TMD patients using a computerized on-line TMD diagnostic system (NUS TMD v1.1). A total of 107 patients (32 male, 75 female) referred to the TMD clinics at the National Dental Centre and National University Hospital participated in this study. The mean age of the predominantly Chinese population (82.2%) was 30.8 years (range from 12 to 64 years). The history questionnaire and clinical examination were input directly into computers by patients and clinicians. A 'Summary of Findings' was then immediately generated by the program based on Axis I and II rules. The data was subsequently exported to SPSS for statistical analysis. About 20.6% of the patients had myofascial pain but only 7.5% experienced limited mandibular opening associated with myofascial pain. The majority of patients (> 80%) did not suffer from disc displacements (right and left joints). The frequency of arthralgia was also low (right joint 8.4%; left joint 7.5%) and only one patient had osteoarthosis of the TMJ. About 78.5% of the patients had low disability with almost equal distribution between low and high intensity pain, 27.1% of the patients were moderately depressed and 11.2% had severe depression. No significant difference in limitations related mandibular functioning scores was observed between normal/depressed patients and between patients with the different graded chronic pain severity classification. The three most frequent jaw disabilities were: eating hard foods (77.6%), yawning (75.7%) and chewing (64.5%). NUS TMD v1.1 is an extremely useful tool in the diagnosis/research of clinical TMD.

Dental technician training in Singapore--a survey.

This postal survey was carried out in 1999 amongst dental technicians in Singapore to assess their status of training, interest towards a local dental technology course and national certification. A hundred and seven questionnaires were sent to technicians of 37 private and two institutional laboratories. Sixty technicians responded giving a response rate of 56.1%. Half of the respondents were above 40 years and more than 40% were not formally trained. Ninety-five percent (95%) agreed that there was a need for national certification. The preferred duration of a structured dental technology course was three years part-time followed by two years full-time. This study has shown that there is a need to train new and existing technicians through introduction of a local structured dental technology course and continuing education. National certification could be introduced when more technicians are formally trained.

Reduction of platelet transfusion- associated sepsis by short-term bacterial culture.

BACKGROUND AND OBJECTIVES: There is as yet no suitable routine laboratory test for a blood transfusion service to detect bacterial contamination in platelets. This study evaluates the effectiveness and the applicability of short-term bacterial culture for such a purpose. MATERIALS AND METHODS: Samples from 5-unit platelet pools were inoculated into an aerobic culture bottle, then monitored for 48 h at 35 degrees C in an automated monitoring and detection system. RESULTS: 26,210 whole-blood-derived platelet components were tested, of which 14 (0.053%) platelet units were found to be contaminated. In addition, nine of the associated red cell units and 4 fresh-frozen plasma units grew the same organisms on culture. CONCLUSION: Short-duration bacterial culture by an automated system is effective and suitable for routine screening in a regional transfusion center.

Albumin genetic variability in South America: Population distribution and molecular studies.

A total of 5,020 individuals living in two southern Brazilian states were screened in relation to albumin types; two variants were found, in Passo Fundo (Nagasaki 2) and Vera Cruz (Tradate 2). Another variant, detected in the northeast, was identified as Porto Alegre 2, which also occurs in other places in Brazil, as well as in India, Pakistan, and Turkey. The results were integrated with those obtained in other studies in South America, yielding a total of 16,941 Amerindians and 23,839 non-Indian subjects. Molecular and physiological studies performed in some of the variants suggested clues to explain the restricted distribution of albumin Yanomama 2 and the widespread occurrence of albumin Maku. Am. J. Hum. Biol. 11:359-366, 1999. Copyright 1999 Wiley-Liss, Inc.

Albumin Church Bay: 560 Lys-->Glu a new mutation detected by electrospray ionisation mass spectrometry.

Albumin Church Bay is a fast migrating genetic variant of human serum albumin which, in a heterozygous subject, formed about 50% of the circulating albumin. Reversed phase peptide mapping and electrospray ionisation mass spectrometry (ESI-MS) indicated that the C-terminal CNBr peptide had decreased polarity associated with a 1 Da increase in mass. Subdigestion of this peptide with trypsin and chymotrypsin revealed that the increased mass was associated with the chymotrypsin fragment VEKCCKADDKETCF (555-568) which had a mass of 1791.1 compared to 1790.2 for its normal counterpart. Sequence analysis of PCR-amplified DNA indicated an A-->G mutation at position 98 of exon 13, which causes a point mutation of 560 Lys-->Glu and results in a 1 Da mass increase.

Clinical experience in temporomandibular joint arthroscopy.

Clinical experience of arthroscopy in 12 temporomandibular joints with a clinical diagnosis of closed lock was described. There were 10 patients and all were females with a mean age of 31.2 years (range 20 to 59 years). The antero-lateral approach was used for entry into 11 joints. The clinical findings were adhesions (64%), fibrillation (64%), anterior displacement of disc (36%) and scuffing of the articular surface of the glenoid fossa (9%). Two of the joints that had arthrocentesis prior to arthroscopy did not show any different findings from the rest. Of the 8 patients who had pre-arthroscopy pain, 7 patients (88%) had reduction of the symptom. Three patients (38%) had complete resolution of pain. The range of mouth opening (measured as maximal incisor opening) increased in all patients two weeks following arthroscopy. The average change in maximal incisor opening was 40.3% with a range of 22% to 85%. The mean follow-up was 34 months (range 4 to 68 months).

Delayed interval delivery in a triplet pregnancy: a case report.

The incidence of multiple pregnancies is increasing due to a surge in the availability of assisted conception techniques. Spontaneous miscarriages, preterm labour and delivery are common complications of multiple pregnancies. In rare circumstances where the leading foetus has been expelled and the rest remain in utero, it is conventional to augment uterine activity to expel the rest of the uterine contents so as to avoid sepsis. Conservative management in such circumstances might allow for foetal lung maturity in the remaining foetuses, but there is limited experience in the world literature. We present a case of conservative management of a triplet pregnancy with early loss of the leading triplet. The delivery interval was 34 days and both remaining triplets survived without any sequelae.

The effect of dentin bonding agents on the microleakage of porcelain veneers.

OBJECTIVES: This in vitro study was conducted to investigate the effect of dentin bonding agents on the microleakage of porcelain veneers cemented on dentin margins. METHODS: Forty human premolars were prepared on both the buccal and palatal surfaces. Each half was randomly assigned to eight groups. The veneer preparation of one group was cut entirely within enamel, to serve as controls. The remaining groups had cervical margins extending 1 mm beyond the cemento-enamel junction. Six dentin bonding agents were tested. The specimens were subjected to thermocycling and evaluated for marginal leakage using a silver nitrate stain technique. After sectioning, the extent of microleakage was measured at four interfaces: (1) incisal porcelain-composite; (2) incisal tooth-composite; (3) cervical porcelain-composite; and (4) cervical tooth-composite. RESULTS: Statistical analysis showed that the cervical tooth-composite interface had a significantly higher leakage value (p < 0.05) than the other three interfaces when the cervical margins were in dentin. SIGNIFICANCE: The dentin bonding agents tested did not significantly reduce the marginal leakage of the porcelain veneers cemented on dentin margins.

Correlation of serum, urinary and salivary CA 125 levels in patients with adnexal masses.

A prospective study was made of 105 consecutive patients admitted to one department of obstetrics and gynaecology for surgery for adnexal masses. The objective was to investigate if CA 125 level is measurable in the urine or saliva and to correlate these measurements with serum CA 125 level in patients presenting with adnexal masses. The final diagnosis and grouping of patients for analysis were based on histopathological examination of the adnexal masses. Serum, urine and salivary samples were collected simultaneously from all patients on the morning before surgery. CA 125 levels in each sample were determined in duplicate using Abbott CA 125-E1A monoclonal test kits (Abbott Laboratories, USA). The mean inter-assay variability was 10%. CA 125 was detectable in the serum, urine and saliva from all the patients and the concentration was highest in the saliva and lowest in urine. There were no discernible differences in the distributions of salivary CA 125 concentrations between patients with ovarian malignancies and those with benign ovarian cysts. In contrast, both serum and urinary CA 125 levels were significantly higher in the ovarian cancer group. There was no correlation in CA 125 concentrations between serum and urine, or between serum and saliva. For detection of ovarian malignancies, the sensitivity, specificity, and positive and negative predictive values for serum CA 125 measurement (> or = 35 U/mL) were 88.9%, 79.2%, 27.6% and 98.7 respectively. The corresponding figures for urinary CA 125 measurement (> or = 10 U/mL) were 88.9%, 66.7%, 19.5% and 98.4% respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

A cadaveric study of the potential damage in arthroscopic examination of the temporomandibular joints.

An arthroscopic study on 22 temporomandibular joints in 13 cadavers was undertaken. Dissections were carried out to correlate the arthroscopic with macroscopic findings in the joints. Iatrogenic damage to the temporomandibular joints and their surrounding tissues was also examined. Correlation between arthroscopy and macro findings was 91.0%. There was no damage to the facial nerve and superficial temporal vessels. Iatrogenic damage to the temporomandibular joint included scuffing of the articular surfaces of the glenoid fossa and articular eminence (31.8%), scuffing of the condylar articular surface (9%), one disc perforation (4.5%) and one perforation of the medial capsule (4.5%). Prevention of iatrogenic injuries is discussed.

A TMJ update.

A wide range of issues are covered in this update. This includes a brief insight into the anatomy of the temporomandibular joint complex, imaging, diagnosis, etiology, psychological implications and the treatment modalities.

A profile of patients with temporomandibular disorders in Singapore--a descriptive study.

This is a descriptive study to establish the profile of 120 consecutive patients seeking relief from symptoms and dysfunction of the masticatory system at the Dental Clinic, Singapore General Hospital from February 1988-September 1988. The mean age of the patients was 29.4 years and females outnumber males by 2:1. The patients complained of TMJ clicking (66%), TMJ pain (55%), painful chewing (47%), headaches (42%), painful opening (37%), jaw locking (33%), and jaw muscle pain (23%). The possible etiological factors were recorded: macrotrauma (27%), stressful episodes (24%), unilateral mastication (53%), clenching (28%), grinding (26%) and excessive chewing habits (10%). Unilateral chewing was significantly associated with pain on opening (p less than 0.05) and joint pain (p less than 0.05). A statistical relationship was found between night grinding and laterotrusive wear of teeth (p less than 0.001). There was evidence that tension headache reported by TMD sufferers was related to temporalis muscle/tendon dysfunction (p less than 0.001).