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Biomedical subjects

J S Dovgan

Publications and source records attributed to J S Dovgan.

4 recordsLinked to original sources
PubMed1995

Electrothermal debracketing: patient acceptance and effects on the dental pulp.

Adhesives bond ceramic brackets so effectively that their removal by mechanical forces can fracture the brackets and may damage the tooth surface. Electrothermal debracketers have been developed to facilitate removal; whether the heat generated will damage the underlying pulp is unclear. In our experiment, a prototype device with a high heat tip was used to remove brackets from premolars in patients. The following parameters were evaluated: (1) time required for removal, (2) patient acceptance, and (3) histologic effect on the pulp. Forty-eight experimental teeth planned for orthodontic extraction were bonded by a filled Bis-GMA composite resin and a monocrystalline sapphire bracket. After the chemically cured composite set, debracketing was performed according to the manufacturer's recommendations. Seventeen premolars were not etched or bracketed and served as controls. The interval between heat application and removal of the bracket was timed. Patients were questioned as to sensations during debracketing. Teeth were extracted at 5 to 7 or 28 to 32 days and histologically prepared. Pulps were evaluated for alterations. Brackets were removed in an average of 2.1 seconds, usually at the bracket/composite interface. Patient acceptance was generally positive. Pulpal necrosis was not observed but, in a number of specimens, slight inflammation and odontoblastic disruption occurred at both observation periods.

Acid Etching, Dental↗
PubMed1993

Adaptation of thermafil components to canal walls.

The desired result of the Thermafil system is described as a centered carrier encased by gutta-percha in apposition to the canal walls. This study examined, in curved canals, the intracanal relationships of: (a) the metal carrier; (b) the surrounding gutta-percha; and (c) the sealer. Following the manufacturer's recommended techniques, 20 resin blocks that had canals prepared with conservative flaring were obturated. Cross-sections were made in the cervical, middle, and apical thirds and were evaluated with a stereomicroscope and scanning electron microscope to determine the location of the Thermafil components. In an additional 20 resin canal preparations obturated with the Thermafil system, the sealer was stained with dye to evaluate coating patterns. Then, these blocks were sectioned at the apex and examined under the stereomicroscope for adaptation at the apical extent of the preparation. In most preparations, the carrier abutted the canal wall in the cervical and middle sections but was usually surrounded by gutta-percha in the apical one third. The adaptation of components showed the most variability at the most apical extent of the preparation; complete encasement of the carrier did not occur in any specimen. Sealer distribution was variable throughout, usually being absent in the apical canal.

Dental Pulp Cavity↗