ABSTRACT
BACKGROUND: It is unclear how the different core designs made of computer-aided design/computer-aided manufacturing (CAD/CAM) system and veneering techniques affect the fracture resistance of endodontically treated teeth. AIM: The aim of this in vitro study is to investigate the effect of different core designs made of CAD/CAM system and veneering techniques on the fracture resistance of zirconia ceramic crowns. MATERIALS AND METHODS: Two types of zirconia copings were designed; the first one with circumferential 0.5-mm chamfer and the second one with circumferential 1-mm deep chamfer. The core specimens (in subgroups) were veneered anatomically with either a layering technique (hand-layer) or with press-on technique resulting in four test groups (n = 12). All crowns were then cemented using self-adhesive resin cement. After that, all specimens were loaded in a universal testing machine until fractured. STATISTICAL ANALYSIS: Data were then analyzed with two-way analysis of variance (ANOVA) (α =0.05). RESULTS: Mean (standard deviation) failure loads for groups ranged from 2412.7 N (±624.6) to 3020.1 N (±1099.8). Two-way ANOVA revealed no statistically significant differences among groups (P > 0.05). Almost all groups showed cohesive failure in the veneering ceramic. CONCLUSIONS: Within the limitations of this laboratory study, neither the core design nor the veneering technique affected the fracture resistance of all-ceramic crowns significantly.
ABSTRACT
The purpose of this study was to determine dental practitioners' opinions, techniques, and materials used for the restoration of endodontically treated teeth (ETT) in Saudi Arabia. A comprehensive nationwide survey regarding treatment strategies of ETT, on the post types and material used for core foundations were distributed either by email or by hard copies to general dentists in different parts of Saudi Arabia (North, South, West, East, and Center). Descriptive statistics were used to analyze the responses to the questions. A total of 164 participants were included in the survey: 72.6% of them were male, and 27.4% were female. 42.1% of the participants were Saudi dental practitioners, whereas 57.9% were non-Saudi dental practitioners. Out of the surveyed dentists, 52% consider post placement for almost every post-endodontic restoration of ETT. The majority of the dentists (54%) believe that a post strengthens ETT. Cast posts and cores were used by 55% of all the dentists, whereas 34% used prefabricated posts exclusively. Screw posts were the most popular prefabricated post type (47%). Composite resin (51%) was preferred for the core foundation, followed by glass ionomer cements (GICs) (26%). Amalgam was seldom used (0.5%). Posts were placed primarily with zinc phosphate cement (51%), followed by GIC (38%). Within the limitations of this survey-based investigation among dental practitioners in Saudi Arabia, it was concluded that the treatment strategies of ETT are in accordance with the current state of evidence-based knowledge.
ABSTRACT
OBJECTIVE: To evaluate the fracture resistance of endodontically treated mandibular premolars restored with glass fiber posts using different luting agents. METHODS: Twenty-four extracted single-rooted mandibular premolars were endodontically treated, and post spaces were prepared to receive fiber posts. They were assigned to three test groups (n=8) according to the type of cement used for the cementation of glass fiber posts: RC group: adhesive resin cement group (etch and rinse), SC group: self-adhesive resin cement group, and GC group: glass ionomer cement group. Teeth in all groups were adhesively restored with a composite resin core material and crowned with Ni-Cr crowns. All specimens were subjected to tangential loading using a universal testing machine until fracture at 30°. Failure loads were recorded, and data were analyzed using one-way ANOVA followed by Tukey's HSD test (α=0.05). RESULTS: Specimens in the RC group were more resistant (258.3±12.7 N) to fracture than those in the SC (218.7±11.1 N) and GC (165.4±8.9 N) groups (P≤0.001). One-way ANOVA indicated that the type of cement had a significant effect on the fracture resistance of endodontically treated lower premolars (P≤0.001). CONCLUSION: The type of cement that was used to fix glass fiber posts was a determining factor of the fracture resistance of endodontically treated lower premolars.
ABSTRACT
OBJECTIVE: This in vitro study aimed to evaluate the fracture resistance of endodontically treated maxillary central incisors with different post systems. METHODS: Fifty-six extracted intact maxillary permanent central incisors were used, treated endodontically (except for the control group), and distributed into the following seven test groups (n=8) depending on the post type: UHT (control group: root-filled teeth without endodontic post), ZRP (prefabricated zirconia post), GFP (prefabricated glass fiber post), CFP (prefabricated carbon fiber post), CPC (custom-made cast post and core), TIP (prefabricated titanium post), and MIP (prefabricated mixed post). The specimens were loaded in a universal testing machine until fracture occurrence. Failure loads were then analyzed with one-way analysis of variance (ANOVA), followed by multiple comparisons by using Tukey's honest significant difference test (α=0.05). RESULTS: Mean (SD) failure loads for groups ranged from 524±73.2 N for CPC to 764.1±156 N for GFP. One-way ANOVA showed significant differences in terms of fracture resistances among groups (P<0.001). Tukey's honest significant difference test showed significant differences in fracture resistance within groups (P≤0.05), whereas no difference was observed between the UHT (control group) and CFP and CPC groups (P≥0.05). CONCLUSION: Endodontically treated teeth restored with zirconia post, glass fiber post, titanium post, or mixed post were more resistant to fracture loads compared with those that were not restored (control group) or restored with either carbon fiber post or cast post and core.
