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ePaper created 2018-03-06, 08:52:14 | version 1.38.0
| trends & applications Fig. 9a Fig. 9b Fig. 11a Fig. 11b Fig. 10a Fig. 10b Fig. 11c Figs. 9a & b: Pre-op periapical radiograph of tooth #26, which had irreversible pulpitis, for which a conservative access cavity was prepared under the crown restoration. Figs. 10a & b: Under magnification, it is possible to see and remove calcification and expose the mesiobuccal (MB) canal. Figs. 11a–c: Under magnification and using an ultrasonic tip, the isthmus was prepared and the second mesiobuccal (MB2) canal was found. Teeth with irreversible pulpitis or necrosis caused by periodontic-endodontic lesions with no or minimal occlusal caries Severe periodontal disease can lead to pulpal pathol- ogy, while the tooth structure can be intact and sound. In such cases, a small conservative access cavity can aid in maintaining the integrity of the affected teeth. This ap- plies similarly to cases of teeth with irreversible pulpitis or necrosis due to trauma or hazardous occlusal stresses. How? The conservative design of access cavities can be ap- plied only when the operator has adequate experience and with the aid of modern technologies, such as a dental operating microscope, ultrasonic tips, modern nickel-ti- tanium rotary files and modern 3-D cleaning. Only under high magnification and with an efficient light is it possible to visualise, through the small access cavity, the entire floor of the pulp chamber, all of the root canal orifices, the main canals, the accessory canals and any obstruc- tions, such as calcifications. Therefore, the use of the op- erating microscope in preparing such small access cav- ities is crucial. Preparing a conservative access cavity is done under the operating microscope and drilling with long shank burs of small diameter (0.8–1.0 mm), for better visibility, to penetrate the pulp chamber. Once in the chamber, ir- rigation with sodium hypochlorite is done in order to elim- inate any debris. Afterwards, using a K-type file of small diameter (0.08 mm), the root canals are probed and ex- plored. Subsequently, any calcifications are visualised under magnification, then removed with ultrasonic tips. If some of the root canals cannot be found at this point, they can be located using ultrasonic tips while cutting into the floor of the chamber. One of the important points in the conventional ex- tended access opening cavity is the complete removal of the pulp chamber roof (which is important to avoid bacte- rial contamination from pulp residue). However, with the modern method of conservative access cavity prepara- tion, this excessive removal of dentine can be avoided by completely cleaning all of the roof of the pulp chamber without leaving any pulp residue. This can be accom- plished using ultrasonic tips designed for endodontics. In this case, it is advised to use a small ultrasonic tip with a small round diamond end or an ultrasonic tip designed for periapical surgery. Such special ultrasonic tips are able to clean the pulp horns and the remaining roof with- out removing any valuable tooth structure (Figs. 1 & 2). An additional point, which was very important in the past, is that the insertion of the files into the root canals must be done in a perpendicular direction to the occlusal surface of the tooth. In order to achieve such an entrance to the canals, sound tooth structure is sacrificed. With the conservative access cavity, we can enter the canals at an angulation that is perpendicular to the coronal one- 14 roots 1 2018