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Biomedical subjects

R Lehman

Publications and source records attributed to R Lehman.

30 records · Page 2Linked to original sources
PubMed1981

In vitro studies on susceptibility of enamel to caries attack after orthodontic bonding procedures.

Oral hygiene plays an important role in the prevention of caries. Therefore, when one is investigating the possible effects of acid etching on caries susceptibility, oral hygiene aspects and the supplementation of fluoride have to be considered. The objective of this investigation was to study the caries susceptibility of etched enamel surfaces in vitro. To simulate the in vivo situation, much attention was given to the influence of remineralization of saliva and fluorides. It was shown that etching and subsequently fluoridating and remineralization increases resistance of enamel against a caries attack.

Acid Etching, Dental↗
PubMed1981

Loss of surface enamel after acid etching procedures and its relation to fluoride content.

The etching of an enamel surface with a strong acid causes loss of surface contour together with a roughening of the enamel, which is necessary for proper adhesion of the bonding agent. It is known that the fluoride concentration plays an important role in the reduction of enamel solubility. The objective of this investigation was to measure the bulk enamel loss because of acid etching with phosphoric acid, with special emphasis on the fluoride content of tooth enamel. It was shown that fluoridated enamel has a high acid-resistant layer 2 to 4 microns in thickness. In some teeth the enamel is locally so resistant that, even after a 3-minute etching period, practically no material is removed. Since considerable amounts of topically applied fluoride ions are known to leak out, it is advisable to omit fluoride application shortly prior to the bonding procedure.

Acid Etching, Dental↗
PubMedDate not supplied

Seizures with onset in the sensorimotor face area: clinical patterns and results of surgical treatment in 20 patients.

It is not generally appreciated that intractable seizures involving the face area are amenable to surgical treatment. Twenty patients with onset of sensorimotor seizures in the face area of the pre- and postcentral gyri have been studied and surgically treated since 1948. Seizures started in the face, tongue, or throat, followed by diverse patterns depending on spread of seizure activity. Two patients had epilepsia partialis continua; 6 had either tonic or atonic drop attacks. All patients had pre- and postcentral face area resections, 12 in the dominant hemisphere. In addition, 3 had more extensive postcentral removal, 7 had temporal lobe, and 4 had small separate or contiguous frontal or parietal resection. Because the seizures were not sufficiently reduced by the first operation, 6 required reoperation; 4 of these patients had residual epileptiform activity on electrocorticogram (ECoG) after the first resection. Three patients had new neurologic signs that did not return to the preoperative level, but in 2 of them the deficit related mainly to higher resection in the central area. All but 2 of these 20 patients had at least moderate seizure reduction. Corticectomy can be performed for treatment of seizures arising in the lower central area and usually does not lead to significant permanent neurologic deficit.

Adolescent↗