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Biomedical subjects

Brett I Cohen

Publications and source records attributed to Brett I Cohen.

11 recordsLinked to original sources
PubMed2004

Comparison instrumentation reamers and files versus a flat-sided design of conventional noninterrupted, flat-sided design.

The in vitro study measured the time required to instrument and shape canals by conventional reamers and files compared with a newly introduced reamer and file system. This experiment was divided into four groups with 10 block samples for each group. The results of instrumentation time demonstrate that the noninterrupted flat-sided design (EZ-Fill SafeSider reamers) produced the fastest times for comparably shaped canals because of reduced engagement of the instrument with the walls of the canal compared with conventional instruments. The conventional designs for both reamers and files result in increased instrumentation time compared with their EZ-Fill SafeSider counterparts.

Acrylic Resins↗
PubMed2003

Inductively coupled plasma-emission spectroscopy and atomic absorption for the use of elemental analysis of a root canal after lasing with a holmium:YAG laser.

It has been reported in the literature that after lasing dentin the dentin surface has a glassy or globular appearance. Many authors believe this to be recrystallized hydroxyapatite. The purpose of this elemental analysis was to see if any of the silica fiber optic was melted and deposited as these globular structures on the canal wall. Two teeth were used. One was hand-instrumented with files and used as the control, the other was lased with a holmium:YAG laser. A 245-micro low OH- fiber was used with a power setting of 0.75 W, 5 Hz, 94.2 J, and 1134 V to lase the root. The roots were microanalyzed for oxygen, phosphorus, silicon, nitrogen, hydrogen, calcium, and carbon. The percentages for all elements tested were the same for both teeth. Therefore, there was no silicon deposited onto the canal wall of the tooth that was lased. It is concluded that the low OH- silica fiber optic was not melted and deposited onto the dentinal canal wall.

Aluminum Silicates↗
PubMed2003

A two-and-a-half year perspective on simplified endodontic techniques.

Simplified Endodontic Techniques (SET), along with EZ-Fill, a bidirectional spiral and epoxy root canal cement, have been used for more than 2 1/2 years. This particular sequence of instrumentation and obturation provides the dentist with predictable and easily attained success. Periapical areas demonstrate healing, and excess EZ-Fill cement is resorbing. Postoperatively, patients experience approximately 80% less pain in both occurrence and intensity. The adoption of SET, along with EZ-Fill, allows dentists to significantly increase their productivity while dramatically improving the quality of their work.

Absorbable Implants↗
PubMed2003

Post design and the optimally restored endodontically treated tooth.

The basics for the sound restoration of endodontically treated teeth have not changed despite the advent of new materials and techniques. Adequate retention for posts and crowns, resistance to cyclic shearing forces, minimal insertional stresses, and even distribution of functional stresses are prime requirements that cannot be compromised without jeopardizing the longevity of the final restoration.

Crowns↗
PubMed2002

Use of a GABA-transaminase agonist for treatment of infantile autism.

This paper describes the use of a GABA-transaminase agonist for the treatment of infantile autism. An approximate one third reduction of GABA and ammonia levels for an autistic patient with noticeable improvement of verbal/language skills and a reduction of repetitious ritualistic self-stimulatory behavior (stimming) was observed. A reduction of the plasma GABA (by administrating a GABA-T agonist, Imipramine) probably results in more axon(s)-to-oligodendrocyte signaling in the corpus callosum and it is postulated that this could result in a reduction of the autistic features for the patient.

4-Aminobutyrate Transaminase↗
PubMed2002

The significance of ammonia/gamma-aminobutyric acid (GABA) ratio for normality and liver disorders.

Cohen has illustrated that extremely high Gamma-aminobutyric acid (GABA) levels in the urine and blood and high plasma ammonia were observed for an autistic male child diagnosed with infantile autism. GABA is a major inhibitory neurotransmitter of the mammalian brain and the enzyme responsible for catabolism is GABA-Transaminase (GABA-T). Elevated levels of ammonia in the plasma results in a decrease in the efficiency for the GABA-T enzyme and this results in higher GABA concentrations after regulation in the liver. It is postulated that a link between plasma ammonia and plasma GABA exists where the concentration of GABA in the plasma is directly related to the ammonia plasma concentration. A ratio of approximately 0.30 (plasma ammonia/GABA) is a consistent finding for normal subjects and for subjects with infantile autism and liver diseases such as hepatic encephalopathy.

4-Aminobutyrate Transaminase↗
PubMed2002

The effects of eugenol and epoxy-resin on the strength of a hybrid composite resin.

The compatibility of different dental materials (root canal sealer and composite core build-up restoratives) is an important factor for a successful restoration. The aim of this in vitro study was to determine the effects on compressive and diametral tensile strength of a classical chemical cure composite resin (Henry Schein Composite Anterior-Posterior dental restorative) when in contact with either eugenol or an epoxy-resin (EZ-Fill) in a variety of situations: (a) eugenol or epoxy-resin added during mixing of a composite resin before curing; (b) vapor exposure to cured samples; and (c) specimens placed directly in eugenol or epoxy-resin (after curing). Compressive strengths and diametral tensile strengths were tested for each group. Only the addition of eugenol during mixing with the composite resin (directly before curing) resulted in specimens that were unable to be tested, because they did not achieve a full cure or hardness. For all other groups, there were no significant differences with respect to either compressive strength (p = 0.17) or diametral tensile strength (p = 0.39). Group 1 (mixed directly with eugenol) was found to be statistically different from groups 2 through 7.

Analysis of Variance↗