Biomedical subjects

B R Lang

Publications and source records attributed to B R Lang.

77 records · Page 5Linked to original sources

PubMedDate not supplied

Dimensional accuracy of two denture base processing methods.

The mucosal surfaces of maxillary complete dentures processed using the SR-Ivocap injection technique and the Lucitone heat-polymerized compression molding technique were compared to a metal master impression to determine if one method of denture processing produced a more accurate denture base. Comparisons were made before and after polishing the prepared bases to determine if changes occur as a result of this procedure. The dental comparator, described by Rupp and others in 1957, was used to compare selected points on the palatal surface of the denture bases. No statistical differences were found in the accuracy of the denture bases processed using either of the two techniques.

Dental Casting Technique↗

PubMedDate not supplied

The role of the implant impression in abutment selection: a technical note.

Selecting the abutment at second-stage implant surgery should combine the experience of both the surgeon and the restorative dentist to avoid complications during prosthetic reconstructions. If an inappropriate abutment is selected, the resultant removal of the abutment and replacement of it with a completely different one is both costly and inefficient. The availability of the healing abutment component has eliminated many of these problems. Making an impression at the implant level allows the dentist ample time to study the restorative needs before selecting the final abutment.

Dental Abutments↗

PubMedDate not supplied

The influence of teeth on denture base processing accuracy.

The Michigan Computer Graphics Coordinate Measuring System was used to determine the influence of denture teeth on the accuracy of processed denture bases. Three different processing methods--compression molding, injection pressing, and vacuum-assisted resin pouring--were used. The presence of denture teeth was determined to affect the accuracy of the processed denture bases of all three techniques. For denture bases without teeth, the compression-molding technique demonstrated significant differences in accuracy; however, no significant differences were found in the injection-pressed or resin-poured denture bases.

Computer Graphics↗

PubMedDate not supplied

Longitudinal electromyographic study of swallowing patterns in complete denture wearers.

A longitudinal electromyographic study of the swallowing activity of the anterior temporal and masseter muscles was performed on 21 subjects with complete dentures. In six patients, the lip activity was recorded. At the pretreatment stage, when the patients had a residual anterior dentition, the peak mean voltages of the elevators showed low values (range 18 to 30 microV), and after denture placement, the anterior temporal muscles showed a further decrease. After denture relining, slight increases in temporal activity were noted at the 1-year stage. During the second year, when no corrections of the dentures were made, the temporal activity decreased below the pretreatment level. The masseter activity showed no significant changes during the 2-year observation period. The mandibular lip showed significantly stronger swallowing activity than the maxillary lip. The mean durations of the swallows were markedly longer than values reported for subjects with a complete natural dentition.

Adult↗

PubMedDate not supplied

4-META polymethyl methacrylate shear bond strength to titanium.

Machined titanium substructures for fixed, complete arch prostheses have been used with various surface pretreatments to enhance acrylic bonding. Since traditional mechanical methods for denture base material retention cannot be used, silane and surface abrasives have been used to enhance retention. The purpose of this study was to determine if a metal bonding denture base material provided a favorable bond strength to machined titanium. Fifteen rod-shaped samples of commercially pure Grade 2 titanium were divided into two groups, five samples representing the control group and 10 samples for the experimental group. The rod samples for the control received no pretreatment, while the experimental samples were pretreated with 110 microns alumina abrasive. Meta-Dent heat-cured polymethyl methacrylate was processed around each sample in a secondary cylindrical shape approximately 0.9 x 1.0 centimeters with the titanium rods extending from each end. A Shell-Nielsen shear test was then performed at a crosshead speed of 0.5 millimeters/minute to determine the bond strength. The experimental group demonstrated a mean bond strength 3.7 times greater than the control group (significant, P = 0.0001, ANOVA). Pretreatment with 110 microns alumina air abrasive significantly enhanced the bond strength of heat-cured metal bonding polymethyl methacrylate to titanium.

Acrylic Resins↗