Use of a provisional restoration as a radiographic guide prior to implant placement.
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Barium↗
Biomedical subjects
Joseph Nissan
Publications and source records attributed to Joseph Nissan.
Heat transfer of impression plasters to an implant-bone interface.
PURPOSE: The purpose of this in vitro study was to measure heat generated at the implant-bone interface caused by exothermic setting reaction of 2 impression plasters. MATERIALS AND METHODS: The study consisted of 20 titanium-alloy abutment impressions connected to a titanium-alloy cylindrical implant embedded in an acrylic-resin mandible in a 37 degrees C water bath. There were 2 types of impression plaster used, Snow-White (Kerr, Romulus, MI) and Xantano (Kulzer, Dormagen, Germany). Temperature changes were recorded via embedded thermocouples at the cervix and implant surface apex. Analysis of variance for repeated measures was used to compare 2 treatment groups. RESULTS: Temperature increased less at the implant apex (1.5 degrees-2.1 degrees C) than at the implant cervix (7.4 degrees-10.5 degrees C). Differences between the 2 impression plasters were statisticallysignificant only at the implant cervical level (P < 0.05). A lower temperature increase was shown with the Snow-White compared with the Xantano. Although both plasters generated an exothermic reaction on setting (mean temperature change 22 degrees C), the increase in the temperature rate of the Snow-White was slower than the Xantano. CONCLUSIONS: Under the conditions of the present study, Snow-White impression plaster appears to be safer to use in implant prosthodontics compared with the Xantano because of its slower and lower exothermic reaction at the implant-bone interface. However, use of the material with the rapid setting time would require more care, such as limiting the volume of material used (e.g., by using a custom tray).
Acrylic Resins↗
Dental management of patients with myasthenia gravis: a literature review.
Myasthenia gravis is a chronic neuromuscular disease characterized by muscular weakness and fatigability. Dental management of patients diagnosed with myasthenia gravis presents a challenge to the dental profession. A MEDLINE search of the English medical (limited to provision in dental care) and dental literature on myasthenia gravis and dental management published between 1975 and 2004 was conducted. In the dental literature, 12 articles were found, and only a few focused on myasthenia gravis and dental care. The purpose of this article was to review and summarize the clinical signs and symptoms associated with myasthenia gravis, highlighting the role of the dental profession in the process of the diagnosis and management of the oral and dental complications that might be associated with the disease, while avoiding myasthenic crisis.
Anesthetics, Local↗
Assessment of the resistance to fracture of endodontically treated molars restored with amalgam.
STATEMENT OF PROBLEM: Controversy exists concerning the preferred type of final restoration of endodontically treated molars regarding their resistance to fracture under occlusal load. PURPOSE: The aim of this study was to assess the resistance to fracture of endodontically treated molars with various degrees of tooth structure loss restored with amalgam under simulated occlusal load. MATERIAL AND METHODS: . The study teeth consisted of 90 noncarious, nonrestored molars stored in physiological saline solution. The teeth were endodontically treated and randomly divided into 9 experimental groups of 10 specimens each with various degrees of tooth loss, ranging from a conservative endodontic access to removal of all cusps. All teeth were restored with a standardized technique to their original contour with amalgam. Each specimen was mounted onto a specialized jig for loading at the central fossa at a 30-degree angle to the long tooth axis. The resistance to fracture, under continuous compressive force at a cross-head speed of 2 mm/minute, was applied by a universal testing machine and was recorded. One-way analysis of variance with Scheffé contrast was used to statistically compare the differences between the groups at significance level P<.05. RESULTS: One-way analysis of variance showed that the group with a conservative endodontic access (1137.6 +/- 311.6 N) and the group with removal of all cusps (1261.4 +/- 195.1 N) presented a significantly higher resistance to fracture when compared with the other groups (P<.05). There was no significant difference in resistance to fracture under the simulated load between the other 7 groups, which ranged from 655.8 +/- 229.4 to 906.3 +/- 168.1 N (P>.05). CONCLUSION: Within the limitations of this study, the endodontically treated molars with a conservative endodontic access or after removal of all cusps that were restored to their original contour with amalgam presented the highest resistance to fracture under a simulated occlusal load.
Analysis of Variance↗
Impression technique for partially edentulous patients.
This article describes an implant impression technique for partially edentulous patients in which impression plaster and irreversible hydrocolloid are used. The technique ensures accuracy, ease of manipulation, and decreased working time.
Alginates↗
The effect of increasing occlusal vertical dimension on face height.
PURPOSE: This study evaluated the effect of increasing occlusal vertical dimension (OVD) on the face height in completely dentate young adults. MATERIALS AND METHODS: Faces of 22 subjects were photographed in a standardized manner in an anterior view. Sequential photographs were taken at intercuspation and clinical rest position, with four complete arch maxillary occlusal overlays increasing OVD in interincisal increments of 2, 4, 6, and 8 mm. Objective measurements were made from the photographs using facial reference markers. Ten observers made subjective evaluations of the resulting changes in face height using the sequential photographs randomly presented. RESULTS: Measurements of the facial markers showed that on increasing OVD, a corresponding change in lower face height was 50% of the interincisal increase in intercuspation and 40% for clinical rest position. ANOVA for repeated measures showed a statistically significant effect of the intraoral increase in OVD on lower face height. However, subjective results showed that observers were not capable of detecting changes in face height caused by an intraoral increase in OVD (2 to 6 mm intrinsically). ANOVA for the difference between dentists and nondentists showed a minimal, but significant, difference between the two groups, with dentists erring slightly less. CONCLUSION: Attempts to alter face height by changing OVD within the range of 2 to 6 mm for esthetic reasons may not be visually distinguishable.
Adult↗