Chlorhexidine allergy due to topical application.

Chlorhexidine is commonly used in dentistry in various forms. Allergic reactions to chlorhexidine of both immediate and delayed type have been reported. Although the incidence is low there may be severe manifestations in some patients. This report presents a case of allergy to chlorhexidine following topical application.

A comparison of the accuracy of patterns processed from an inlay casting wax, an auto-polymerized resin and a light-cured resin pattern material.

Background: Traditionally, inlay casting waxes have been used to fabricate patterns for castings. Newer resin pattern materials offer greater rigidity and strength, allowing easier laboratory and intraoral adjustment without the fear of pattern damage. They also claim to possess a greater dimensional stability when compared to inlay wax. Aims: This study attempted to determine and compare the marginal accuracy of patterns fabricated from an inlay casting wax, an autopolymerized pattern resin and a light polymerized pattern resin on storage off the die for varying time intervals. Materials and Methods: Ten patterns each were fabricated from an inlay casting wax (GC Corp., Tokyo, Japan), an autopolymerized resin pattern material (Pattern resin, GC Corp, Tokyo, Japan) and a light-cured resin pattern material (Palavit GLC, Hereaus Kulzer GmbH, Germany). The completed patterns were stored off the die at room temperature. Marginal gaps were evaluated by reseating the patterns on their respective dies and observing it under a stereomicroscope at 1, 12, and 24 h intervals after pattern fabrication. Results: The results revealed that the inlay wax showed a significantly greater marginal discrepancy at the 12 and 24 h intervals. The autopolymerized resin showed an initial (at 1 h) marginal discrepancy slightly greater than inlay wax, but showed a significantly less marginal gap (as compared to inlay wax) at the other two time intervals. The light-cured resin proved to be significantly more dimensionally stable, and showed minimal change during the storage period. Conclusion: The resin pattern materials studied, undergo a significantly less dimensional change than the inlay waxes on prolonged storage. They would possibly be a better alternative to inlay wax in situations requiring high precision or when delayed investment (more than 1 h) of patterns can be expected.

A study to determine whether the anterior and posterior vibrating lines can be distinguished as two separate lines of flexion by unbiased observers: a pilot study.

CONTEXT: By convention, the posterior palatal seal area is located on the palate between the anterior and posterior vibrating lines. However, there are opposing views on whether the anterior and posterior vibrating lines can be distinguished as two separate lines of flexion. AIMS: The study was carried out to determine whether the anterior and posterior vibrating lines can be distinguished as two separate lines of flexion by unbiased observers. A second part of the study was formulated to evaluate whether the palpatory method correlated with the nose-blowing method in locating the anterior line of flexion. MATERIALS AND METHODS: Twenty-three dental undergraduate clinical students were selected as observers. Twenty-three edentulous patients were randomly selected. The students were asked to record the anterior and posterior vibrating line on one patient each using two differently colored marking pencils. Also, the anterior vibrating line was marked by the palpatory method (using T burnisher) using a third colored marking pencil. The marked lines were then transferred onto the previously made impression of modeling plastic. RESULTS: Of the 23 recorders used in the study, 19 could locate separate anterior and posterior lines of flexion. In 4 cases, the anterior and posterior lines of flexion coincided and were not distinct. In 20 cases, the palpatory method produced a line anterior to the line located by the Valsalva maneuver. CONCLUSIONS: The anterior and posterior vibrating lines could be located by the undergraduate students as two separate lines of flexion when the appropriate action was elicited for each of them; and the palpatory method produced a line slightly anterior to the anterior vibrating line located by the Valsalva maneuver.