Soft tissue-ceramic interface: true parameter for successful esthetics.

Thirty-six maxillary central incisors were endodontically treated and restored with a post and core and cast crown. Three different post and core systems were evaluated. Restored teeth were fatigue-loaded until preliminary failure of the casting occurred as detected by a strain gauge bonded across the lingual margin of the cast crown. After preliminary failure, fatigue loading was continued for 100,000 load cycles with the crown margin exposed to basic fuschin dye. Teeth were then immersed in dye for 24 h, sectioned, and evaluated for leakage. There was no significant difference in the number of load cycles required to cause preliminary failure among the three post and core systems. Leakage occurred in all three groups, with no significant difference between groups. The occurrence of preliminary failure is clinically undetectable, yet it allows leakage between the restoration and tooth that may extend down the prepared post space.

Crowns↗

PubMed1998

Are posts mandatory for the restoration of endodontically treated teeth?

In this era of fiscal and professional accountability, variations in the utilization of posts to improve the retention of crowns or other restorations on endodontically treated teeth are no longer acceptable. This practice ignores not only the potential for root perforations during post space preparations, but also the adhesive properties of modern resin-based materials. Since the retention of restorations hinges on many other factors, the placement of posts does not necessarily assure service quality and may even lead to deleterious changes. The need to reappraise the utilization of posts in the restoration of endodontically treated teeth cannot be overstated.

Crowns↗

PubMed1998

Evaluating dental office ergonomic. Risk factors and hazards.

Concerns about ergonomic risk factors have been growing among health care and other workers. The authors undertook a study to determine the presence of certain ergonomic risk factors in typical tasks performed by dentists and dental hygienists. They further investigated--by means of electromyography and goniometry--the force, frequency and duration of the task. The study suggests that when a task's duration, force and frequency are accounted for, scaling, polishing, flossing and probing activities do not represent exposure to high ergonomic risk.

Crowns↗