Endodontic access of all-ceramic crowns

Diagnosis of Vertical Root Fractures with Optical Coherence Tomography

“…Furthermore, a craze line might propagate into a fracture in certain conditions or along different levels of the same root (20,21) (Fig.3). Although some authors try to define the different terms (4,22), many others avoid the definitions (16,20,23) or only refer to the clinical or diagnostic aspects (24). Still, a VRF is usually referred to as a "through and through" crack with a connection between the canal and the outer root surface or periodontal ligament (21,25).…”

Resistance to fracture of two all-ceramic crown materials following endodontic access

“…With the exception of 1 crown cracking at the gingival collar during removal from the tooth, chipping was noted around the access openings of all of the crowns. Sutherland et al 7 compared the access openings made with diamond rotary cutting instruments and tapered fissure carbide burs on 42 Dicor crowns. The authors concluded carbide burs produced more fractures and craze lines than diamond rotary cutting instruments.…”

Fracture resistance assessment of endodontically accessed hybrid ceramic crowns repaired with two different protocols

“…(26,27) Endodontic access openings through all ceramic restorations may initiate microcracks which could propagate with time and cause fracture. Considering these challenges, access openings were done with a diamond rotary cutting instrument in a high speed hand piece with heavy water spray in accordance with Sutherland et al (28) Haselton et al (29) and Oden et al (30) in order to avoid the vibration of low speed hand pieces which may produce cracks at the ceramic margins. Diamonds were the instrument of choice rather than carbide burs because they are more suited for ceramics as the mechanism of grinding leads to a smoother cut with less vibration.…”