Thermal analysis of commercial Gutta-percha using differential scanning calorimeter and dynamic mechanical thermal analysis.

Gutta-percha is the most widespread root canal filling material and knowledge of its chemical and thermomechanical properties is of a great interest to its use in clinical dentistry. In the present investigation, the results from differential scanning calorimeter were compared with those obtained by dynamic mechanical thermal analysis. A significant correlation was established between these results and the chemical composition of six different commercial samples of gutta-percha.     

A postero-anterior cephalometric evaluation of adult open bite subjects as related to normals.

Reduced nasal airflow can be the result of enlarged adenoids, hypertrophic turbinates, severely deviated nasal septum, or even narrow nasal cavities. The question of whether the width of the nasal cavity may influence certain facial dimensions examined on the postero-anterior cephalometric X-ray was evaluated through the study of two different groups of subjects. Possible intercorrelations between some other frontal dimensions were also examined in these subjects. The first group consisted of 15 males and 22 females aged from 17 to 25 years diagnosed as having an anterior open bite of at least 2 mm. The second group consisted of 20 males and 16 females aged from 19 to 25 years with a normal Class I skeletal and dental pattern. Postero-anterior cephalometric X-rays were taken for all individuals and the following dimensions were measured: facial width, nasal width, maxillary width, mandibular width, nasal height, and lower facial height. Statistical analysis was performed for the primary linear measurements as well as for certain ratios. Nasal height and lower facial height were found to be significantly increased in both males and females of the open bite group. The ratios of nasal width to lower face height, as well as nasal width to nasal height, were found to differ significantly only between open bite and normal females, being higher in the latter group.     

Frontal cephalometric study of dentofacial morphology in children with bilateral clefts of lip, alveolus and palate

The transverse dentofacial morphology of 36 children with bilateral cleft lip, alveolus and palate was studied by means of a frontal proportional cephalometric analysis at the ages of three, eight and twelve years. Comparison of the variables of the cleft group was made with the normal dimensions as obtained from the Bolton cephalometric templates. The results indicated that the BCLP group presented characteristics and significant differences from the normal in the dimensions of the nasal septum width and the mandibular intergonial width as they are both related to the interorbital width, the maxillary intermolar width as it is related to the mandibular intermolar width and the maxillary width as it is related to the mandibular intergonial width at all three ages. The maxillary base and intermolar widths, although significantly different at the ages of three and eight years, showed no significant deviation from normality at the age of twelve years. Following orthodontic treatment between the ages of seven to twelve years, the maxillary intermolar width of the treated subgroup was significantly larger than in the untreated subjects.     

A clinical study of rest position using the Kinesiograph and Myomonitor.

The clinical study was designed to study the vertical dimension of rest position and mandibular closure to maximum intercuspation of the teeth before, during, and after relaxation procedures on 14 subjects with stable dentitions. The findings call attention to the potential of both the Myomonitor and the Kinesiograph for research and clinical use, to the physiologic need for flexibility of the vertical dimension of rest position, and to the importance of measuring all three dimensions when examining the rest position.     

Healing of onlay mandibular bone grafts covered with collagen membrane or bovine bone substitutes: a microscopical and immunohistochemical study in the sheep

The objective of this study was to evaluate the role of collagen membrane and Bio-Oss coverage in healing of an onlay graft to the mandible. Twelve adult sheep each received an onlay bone graft (experiment 1), bone graft+Bio-Gide (experiment 2), and bone graft+Bio-Oss/Bio-Gide (experiment 3) on the lateral surface of the mandible. The animals were euthanized at 4, 8, 12 or 16 weeks after surgery, and findings were analysed by routine microscopy and immunohistochemistry for proliferation (Ki67) and apoptotic (Caspase-3) markers. Grafts were fully incorporated in all specimens. Pronounced resorption was observed in experiment 1. Minimal loss of graft volume was seen in experiment 2 specimens without membrane displacement. A remarkable increase in the augmented region of the mandible was observed in experiment 3. A high number of osteoclasts were expressed within the grafts during the early healing period, and thereafter declined markedly. Osteoblasts within the grafts expressed a moderate level of Ki67 at 8 weeks, which thereafter declined markedly. The strongest expression of Caspase-3 on the bone surface was observed after 16 weeks. In conclusion, the effect of collagen membrane coverage on bone graft volume maintenance was dependent on membrane stability during healing. An autogenous bone graft covered with Bio-Oss particles resulted in a remarkable increase in augmented lateral surface of the mandible. The late stage of bone graft healing was associated with a high apoptotic induction pathway of osteoblasts lining the surfaces of the new bone, demonstrated by strong positive Caspase-3 immunoreactivity.     

The effect of periodontal treatment on glycemic control in patients with type 2 diabetes mellitus

BACKGROUND, AIMS: This study was designed to explore the effect of periodontal therapy on glycemic control in persons with type 2 diabetes mellitus (DM). METHODS: 36 patients with type 2 DM (treatment group) received therapy for adult periodontitis during an 18-month period. A 36-person control group was randomly selected from the same population of persons with type 2 DM who did not receive periodontal treatment. RESULTS: These groups were well matched for most of the parameters investigated. During the nine-month observation period, there was a 6.7% improvement in glycemic control in the control group when compared to a 17.1% improvement in the treatment group, a statistically significant difference. Several parameters that could confound or moderate this glycemic control were explored. These included the treatment of non-dental infections, weight and medication changes. No moderating effect was associated with any of these variables. However, there were too few subjects in the study to have the statistical power necessary to assess these possible moderators of glycemic control. CONCLUSIONS: We interpret the data in the study to suggest that periodontal therapy was associated with improved glycemic control in persons with type 2 DM.     

Disodium clodronate in the treatment of diffuse sclerosing osteomyelitis (DSO) of the mandible

Diffuse sclerosing osteomyelitis (DSO) of the mandible is a chronic condition, the cause of which is not known. Jaw pain, occurring irregularly, is a typical symptom. The aim of the study was to assess the effectiveness of disodium clodronate for relieving pain in patients with DSO. Disodium clodronate is a bisphosphonate used to treat diseases of bone and calcium metabolism. Ten DSO patients experiencing pain received disodium clodronate or placebo intravenously on a randomized double-blind basis. Both minimum (300 mg) and maximum (900 mg) doses were well tolerated. Disodium clodronate administration did not result in better immediate pain relief than placebo administration. However, 6 months after treatment there was a statistically significant difference in pain intensity between the groups, with the disodium clodronate group experiencing significantly less pain.     

Use of industrially available aluminium-bronze alloys for cast restorations. I. Preliminary study

A bstract — A preliminary study of the use of three industrial aluminium bronze alloys and one silicon bronze alloy for dental castings is reported. The results indicate that satisfactory marginal fit was achieved for full crown castings, and further investigation in the use of these alloys is warranted.