Applications of digital medical techniques for dental dysplasia / 中华口腔医学杂志

Dental dysplasia are abnormalities in teeth structure, morphology, number and eruption caused by genetic and environmental factors during dental development. Digital medical techniques, as the current hot spot of medical research, bring great challenges and opportunities to modern stomatology. The applications of digital techniques, such as digital diagnosis method, digital virtual simulated design, three-dimensional printing, static and dynamic guidance and artificial intelligence, can provide a more accurate, efficient, automatic and intelligent modern concepts and patterns for epidemiology, diagnosis, multidisciplinary treatment and outcome assessment of dental developmental anomalies.

A micro-computed tomographic study of the isthmus in the root canal system of mandibular first molar / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the prevalence and configuration of the isthmuses in the apical 6 mm of the mesial and distal roots of Chinese mandibular first molar by means of micro-computed tomography.</p><p><b>METHODS</b>Thirty-six extracted human mandibular first molars were selected. Specimens were subject to micro-CT and a slice thickness of 30 microm was obtained in the apical 6 mm of the roots examined. The number of sections showing isthmuses at each apical level was recorded. Three-dimensional images of isthmuses of mandibular first molars were reconstructed and observed.</p><p><b>RESULTS</b>The mesial roots of human mandibular first molars had a high incidence of isthmus. The isthmus incidence was greatest 4-6 mm from the apex in human mandibular first molar, with prevalence figures of 49.5%-66.1% and 17.3%-17.8% in mesial and distal roots, respectively. The chi-square test indicated a significant difference in the distribution of isthmuses between the two roots (P < 0.01).</p><p><b>CONCLUSIONS</b>The mesial roots of human mandibular first molars have a high incidence of isthmus, which may have clinical implications especially when surgical endodontics is performed on the mesial roots of mandibular molars.</p>

Management of intracanal separated instruments with the microsonic technique and its clinical outcome / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the clinical effect of microsonic technique on removal of intracanal separated instruments.</p><p><b>METHODS</b>Forty-four teeth with 47 intracanal separated instruments, which could not be successfully managed by conventional methods, were endodontically treated with ultrasonic instruments under dental operating microscope. The success rate was calculated and the cases were reviewed 5 to 19 months after retreatment.</p><p><b>RESULTS</b>Thirty-four (34/47) separated instruments in 33 (33/44) teeth were completely removed with a success rate of 75%. Thirteen separated instruments in 11 teeth, however, could not be eliminated from the canals. Root canal perforation or vertical fracture was not found. None of these teeth showed periapical deterioration in the follow-up.</p><p><b>CONCLUSIONS</b>The combined use of dental operating microscope and ultrasonic instruments in endodontic treatment enriched the way of managing complicated cases of intracanal separated instruments.</p>