Biomedical subjects

A Koerber

Publications and source records attributed to A Koerber.

5 recordsLinked to original sources

PubMed2000

Recovery of sensibility after digital neurorrhaphy: a clinical investigation of prognostic factors.

A multicenter retrospective review of 172 epineural digital nerve repairs using microsurgical techniques was performed. A total of 71 men and 25 women ranged in age from 5 to 64 years (mean age, 33.3 years). Sharp injuries occurred in 55.6% of patients and mild crush occurred in 44.4%. Isolated nerve injuries occurred in only 24.6% of patients. The majority of digital nerve injuries involved other structures: flexor tendons (33.5%), tendons and fractures (9.0%), and fractures (4.2%). Replantations were performed in 18 digits (21.6%) and revascularizations in 7 digits (7.2%). Injury to repair was less than 1 day in 47.8%, 2 to 7 days in 22.6%, 8 to 30 days in 23.3%, and 31 to 300 days in 6.3%. Follow-up averaged 22.2 months (range, 6-77 months). The authors found a significant correlation between age and recovery of sensibility as measured by Weber's two-point discrimination test (p < 0.001). Patients older than 40 years demonstrated significantly poorer recovery of sensibility than patients younger than 40 years. A trend of better sensibility return was noted in the younger age decades (<40) with declining age; however, the intergroup differences were not significant. There was also a significant correlation between severity of injury and recovery of sensibility (p < 0.001). Sharp injuries (8.2 mm) demonstrated significantly improved recovery of sensibility compared with mild crush (10.8 mm). Fractures (11.1 mm), fractures and tendon involvement (11.4 mm), and replantations (11.8 mm) demonstrated significantly diminished recovery of sensibility compared with isolated nerve injuries (7.9 mm), tendon involvement (8.1 mm), and revascularizations (9.3 mm). There did not appear to be any significant difference in recovery of sensibility according to gender, digit involved, radial or ulnar side of digit, median or ulnar nerve distribution, level of injury (except for the metacarpophalangeal joint and the distal palmar crease where most replantations occurred), or time interval from injury to repair. There was a weak negative correlation between length of follow-up and recovery of sensation.

Adolescent↗

PubMed2000

Radiovisiography in the detection of periapical lesions.

The periapical areas of 16 teeth from 6 human mandibular jaw specimens were randomly examined by 3 observers using conventional radiography with Kodak E-speed film and radiovisiography (with variable contrast and with fixed contrast). Each periapical area was examined preoperatively and after #2, #4, #6, and #8 sized bur periapical lesions were created in the cortical bone. The three radiographic methods were compared by repeated-measures ANOVA of the accuracy scores for the 16 periapical lesions. Accuracy increased with size of lesion, but did not vary by method. Repeated-measures ANOVA of the accuracy scores of only the smallest and no lesion condition showed that conventional radiography and radiovisiography (variable contrast) have opposite strengths. Conventional radiography tended to be more accurate in the no lesion condition, whereas radiovisiography using variable contrast was somewhat more accurate in the smallest lesion condition. The accuracy of radiovisiography with fixed contrast was not significantly different from the other two methods.

Analysis of Variance↗

PubMed2000

Effect of alendronate on immature human dental root explants.

This study investigated the use of alendronate in the formation of new dentin in vitro. Extracted human premolar and molar teeth with immature apices were grown in tissue culture medium for 60 days. Six control specimens were grown without alendronate in the medium, and 22 experimental specimens were grown with alendronate at [10(-9) M] in the medium. Newly formed dentin was stained with tetracycline and procion brilliant red at days 1 to 3, 30 to 33, and 60. Specimens were decalcified and 5-micron sections were prepared for examination using fluorescent microscopy. New dentin formation was measured in microns at the most apical region, at 125-micron from the apical measurement and at 250-micron from the apical measurement. The alendronate group had 57.15% more growth than the control group at the most apical region, and this difference was significant (p = 0.0001). The results indicate that alendronate at [10(-9) M] is effective in accelerating dentin formation in vitro.

Alendronate↗

PubMed1999

Super-EBA as an endodontic apical plug.

Forty extracted human single-rooted teeth were sequentially instrumented with nickel-titanium rotary files to a size 0.36 mm at the working length. Ten teeth were randomly assigned to the two control groups. The other 30 teeth were randomly divided into three groups and were obturated by a 5-mm apical plug of either Super-EBA, IRM, or laterally condensed gutta-percha and Roth's sealer. After 2 days, and at 1 month, the samples were tested for microleakage by the fluid filtration system under 15 psi. The negative controls were used to consider the time that it took the fluid filtration system to stabilize. A one-way analysis of variance showed that, at 1 month post obturation, there was no statistical difference in the ability of the three materials to seal the apex from coronal microleakage. However, at 2 days, Super-EBA gave a significantly better seal than IRM or laterally condensed gutta-percha and sealer.

Analysis of Variance↗

PubMed1999

Corrosion in stainless-steel and nickel-titanium files.

This study evaluated and compared the corrosion susceptibility of stainless-steel and nickel-titanium (NiTi) endodontic files immersed in sodium hypochlorite. For each of the stainless-steel files (Kerr K-Flex, Caulk Flex-O, and Union Broach Flex-R) plus the NiTi files (Union Broach NiTi and Tulsa NiTi), the cutting flutes of 24 ISO size 20 files were immersed into 5.25% sodium hypochlorite. Their open circuit potential (OCP) was recorded for 1 h on a strip chart with high impedance. The strip chart recording for each file was classified into a stability score: (i) stable, (ii) unstable, or (iii) erratic. The OCP was measured by a potentiostat and a standard calomel electrode reference. The OCP classification of unstable and erratic for the files evaluated were as follows: K-Flex (16%), Flex-R (12%), Flex-O (75%), Union Broach NiTi (62%), and Tulsa NiTi (0%). After OCP testing, each of the 120 files was inspected by light microscopy at x 25. The frequencies of visually observed corrosion were detected as follows: K-Flex (2/24), Flex-R (1/24), Flex-O (6/24), Union Broach NiTi (2/24), and Tulsa NiTi (0/24). There was a significant difference in corrosion frequency between brands when evaluated by OCP and light microscopy; however, there was no significant difference between stainless steel and NiTi.

Analysis of Variance↗