ABSTRACT
Improper treatment plan, designing of the restorations and the selection of the restorative materials resulted in patient unsatisfactory. The purpose of this case is to create a hygienic and esthetic restoration for the patient with good social acceptance. Individual all ceramic zirconia crowns were fabricated for a 54-year-old male patient who attended the clinic with a multiunit joined porcelain fused to metal restoration. The esthetic treatment with all ceramic computer-aided design and computer-aided manufacturing crowns resulted in improved facial aesthetics; psychological status and social life of the patient. In addition to that, patient can practice standard oral hygiene in the present of separated crowns
ABSTRACT
Background: Ceramo-metal crowns are commonly indicated for restoration of extensively damaged posterior teeth. Prosthodontists have ability to prepare teeth for retention, resistance, and longevity of the restorations
Objectives: The aim was to measure the degrees of the taper and convergence angle [CA] of dies prepared by different prosthodontists at Assir region, and the effect of the tooth position on the taper and CAs degrees
Materials and Methods: Eighty stone dies were obtained from specialist dental clinics, College of Dentistry at King Khalid University [KKU], Muhayil, Kamis-Mushayat and Assir Dental Centers. All the dies were mounted with the occlusal plane of the prepared teeth parallel to the floor. Photographs of buccal and proximal aspects were taken for each die. The photographs were transferred into a personal computer, AutoCAD software program was used to measure the mesio-distal [MD] and bucco-lingual [BL] taper and CA of each preparation. Analysis of variance [ANOVA] was used to test the level of significance difference, which was set at 5%
Results: The highest values were observed with Kamis-Mushayat Center for BL [31.89] taper and Assir Center for MD [38.21] and overall CA degrees [34.38]. The mean values for KKU specialist dental clinics were the lowest for all parameters of CA degrees [22.91]. ANOVA showed statistically significant [P < 0.05] differences with the mean CAs between all the four dental centers. The MD, BL taper and overall CA for all the premolar teeth was significantly lower than molar teeth. No statistical difference in the overall CA between maxillary and the mandibular arch [P > 0.05]
Conclusions: The values of MD, BL taper and CA degrees carried-out by specialist at College of Dentistry, KKU are the lowest values of the prepared teeth compared with other dental centers at Assir region. There was no significant difference between maxillary and mandibular arch, while taper and CA are lower at premolars comparing to molars. The recommended taper and CAs are difficult to be achieved clinically
ABSTRACT
PURPOSE: Porcelain fused to metal (PFM) crowns provide the best treatment option for teeth that have a large or defective restoration. More than 20% of teeth with PFM crowns or bridges require non-surgical root canal treatment (NSRCT). This may be due to the effect of restorative procedures and the possible leakage of bacteria and or their by-products, which leads to the demise of the tooth pulp. Thus, this study was planned to compare the ability of the restorative materials to seal perforated PFM specimens. MATERIALS AND METHODS: The study evaluates the ability of amalgam, composite or compomer restorative materials to close perforated PFM specimen's in-vitro. Ninety PFM specimens were constructed using Ni-Cr alloys and feldspathic porcelain, and then they were divided into 3 groups: amalgam (A), composite + Exite adhesive bond (B) and compomer + Syntac adhesive bond (C). All the PFM samples were embedded in an acrylic block to provide complete sealing of the hole from the bottom side. After the aging period, each group was further divided into 3 equal subgroups according to the thermocycling period (one week for 70 cycles, one month for 300 cycles and three months for 900 cycles). Each subgroup was put into containers containing dye (Pelikan INK), one maintained at 5degrees C and the other at 55degrees C, each cycle for 30 sec time. The data obtained was analyzed by SPSS, 2006 using one way ANOVA test and student t-test and significant difference level at (P<.01). RESULTS: The depth of dye penetration was measured at the interfaces of PFM and filling materials using Co-ordinate Vernier Microscope. The lowest levels of the dye penetration for the three groups, as well as subgroups were during the first week. The values of dye leakage had significantly increased by time intervals in subgroups A and C. CONCLUSION: It was seen that amalgam showed higher leakage than composite while compomer showed the lowest level of leakage.