The effect of immediate dentin sealing and optical powder removal method on the fracture resistance of CAD/CAM-fabricated endocrowns.
OBJECTIVE
To evaluate the effect of immediate dentin sealing and optical powder removal method on the fracture resistance of CAD/CAM-fabricated ceramic endocrowns.


METHODS
Seventy-eight extracted premolars were endodontically treated. Standardized endocrown preparations were done in 60 teeth. Teeth were divided equally (n = 10) depending on the treatment of dentin (delayed sealing [DS] or immediate sealing [IS]), and the methods of optical powder removal (air-water spray washing [AW]; microabrasion [MA]; or aqueous suspension of pumice [PB], followed by air-water spray washing). After cementation, specimens were thermocycled (5,000 cycles, 5°C/50°C) and stored in distilled water for 1 week. Specimens were loaded in compression using a universal testing machine until failure. Failure load was recorded, and modes of failure were examined under a stereomicroscope. Micromorphological evaluation of different dentin treatments was done under SEM (n = 3). Results were analyzed using two-way ANOVA and Bonferroni post hoc multiple comparison tests (α = 0.05).


RESULTS
Fracture resistance of all IS groups was significantly lower than DS groups, except for AW. There was no statistically significant difference between powder removal methods.


CONCLUSIONS
Immediate dentin sealing does not improve the fracture resistance of endocrown restorations. Air-water spray washing is adequate to remove the optical powder after optical scanning impression taking.
Hatem M
HM
El-Damanhoury
Marianna
M
Gaintantzopoulou
D000179:Acrylates / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D017076:Computer-Aided Design; D003442:Crowns; D001840:Dental Bonding / Q000379:methods*; D045662:Dental Etching / Q000379:methods; D018772:Dental Marginal Adaptation; D003776:Dental Porcelain / Q000737:chemistry; D003777:Dental Prophylaxis / Q000379:methods; D019232:Dental Restoration Failure; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D061848:Optical Imaging / Q000379:methods*; D017680:Potassium Compounds / Q000737:chemistry; D011208:Powders; D011312:Pressure; D019279:Resin Cements / Q000737:chemistry; D018915:Root Canal Preparation / Q000379:methods; D017693:Sodium Bicarbonate / Q000737:chemistry; D007507:Therapeutic Irrigation / Q000379:methods; D019231:Tooth Preparation, Prosthodontic / Q000379:methods
D000179:Acrylates; D000538:Aluminum Silicates; D017220:Dentin-Bonding Agents; D017680:Potassium Compounds; D011208:Powders; D019279:Resin Cements; C078484:Syntac dentine adhesive; C082340:Vita Mark II; D003776:Dental Porcelain; C016447:feldspar; C103502:Variolink; C040415:heliobond; D017693:Sodium Bicarbonate