RESUMEN
This in vitro study compared the load necessary to cause porcelain bond failure on porcelain covering the labial and palatal surfaces compared with porcelain covering only labial surface in metal ceramic crowns of maxillary anterior teeth. 30 metal ceramic crowns for maxillary central incisor tooth were fabricated in two groups (Groups A and Group B) (15 samples in each group). In group A, palatal ceramo-metal junction was placed at cervical 1/5th of palatal surface. In Group B the palatal ceramo-metal junction was placed at palato incisal line angle and these crowns were subjected to load using Instron testing machine. Mean failure load for group A is statistically highly significant than Group B. (P value = 0.0025). But both these values are higher than the reported mean maximal incising forces.
Asunto(s)
Fuerza de la Mordida , Coronas , Recubrimiento Dental Adhesivo , Diseño de Prótesis Dental , Humanos , Incisivo , Ensayo de Materiales , Maxilar , Aleaciones de Cerámica y Metal , Resistencia a la TracciónRESUMEN
The photosensitizing properties of p-nitroacetophenone (PNAP), a well-known radiosensitizer, have been studied in near UV region. The mechanism of PNAP photosensitization has been investigated by testing the efficiency of singlet oxygen production using photooxidation of 2,2,6,6-tetramethylpiperidine (TEMP) and photodegradation of guanosine. In both the cases, the enhancement effect of deuterated solvents has been observed. Results of these experiments suggest the significant role of type II mechanisms in PNAP photosensitization.