PubMed · 6584804
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
B Symons. 1984. Endodontic therapy using hemisections and root amputations.. https://pubmed.ncbi.nlm.nih.gov/6584804/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Twenty-four cases treated by periapical surgery--which 2 to 6 yr after surgery were classified radiographically as incomplete healings (scar tissue)--were further followed, extending the observation period to 8 to 12 yr. One case healed completely, 1 failed, and 22 were still recorded in the same healing group. All the 22 scar tissue cases were characterized by a reduction of the defect in bone. In 13 cases, continuous periodontal structures were seen and the defect thereby separated from the root. The findings support the conclusion that cases clearly showing features of incomplete healing (scar tissue) at the regular follow-up 1 yr after surgery can be regarded as successes. They need not be recorded for further systematic control. A general follow-up program for apicectomy cases is suggested.
The purpose of this study was to evaluate the integrity of resected root-end surfaces of extracted human teeth after using ultrasonic tips at low or high frequencies for root-end preparation. Thirty bilaterally matched pairs of single-rooted human teeth had root-end resections using a low-speed diamond saw and were examined for root-end cracks. The matched pairs of teeth were then divided into two experimental groups, with one member of each pair being placed in each group. In group 1, root-end preparations were made with an ultrasonic tip on the lowest frequency setting. The preparations in group 2 were done on the highest power setting. Two investigators again examined the resected root-ends using a stereomicroscope at x20 to x63 and recorded the numbers, types, and location of the cracks. Three types of cracks were observed: canal cracks, intradentin cracks, and cemental cracks. There were significantly more root-ends with cracks after ultrasonic root-end preparation than after root-end resection only. In root-ends that had any cracks, significantly more canal cracks per root occurred when the ultrasonic tip was used on the high-frequency setting for root-end preparation than when the ultrasonic tip was used on the low power setting.
Modified ultrasonic tips are used to prepare rootend cavities during endodontic surgery. The purpose of this study was to determine whether such tips are prone to breakage during use. Ten different tip designs were driven by an ultrasonic unit at maximum power. Multirooted teeth were instrumented, the apex removed, and the tooth was placed horizontally on a pan balance. The apex was instrumented by each ultrasonic tip in turn for 15 min, with the load being increased by 100 g every 5 min. Those tips with curvatures of 70 degrees or greater fractured within the first 5-min loading period. Breakage occurred approximately 2 to 3 mm from the end and always at a bend. Scanning electron microscopy revealed that the fractures were brittle in nature, with little change in the remaining section. Two tips bent: one isthmus preparation tip and one silver point removal tip. All the other designs were deemed satisfactory after experimentation. This study shows that fracture of ultrasonic tips can occur and is related to the degree of bending.