Study on the height of marginal ridge to cusp in posterior teeth and its effect on brackets placement / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To measure the vertical height of mesio-distal marginal ridge to cusp in posterior teeth, which may be helpful to brackets positioning.</p><p><b>METHODS</b>The study groups comprised of 60 patients (30 men, 30 women, mostly aged 12-14 years) who underwent orthodontic treatment without tooth extraction and matched the Andrews normal occlusion standard after treatment. Study model of each patient was made. Three-dimensional laser measurer was used to evaluate the vertical height of mesio-distal marginal ridge to mesial cusp in posterior teeth. The data were stored in a personal computer and submitted to statistical analysis of paired t test.</p><p><b>RESULTS</b>No statistical significant difference was found in the same teeth between men and women. Not only in maxilla but also in mandible, there was no significant difference between the left and the right (P>0.05). The average vertical height of maxillary first premolars was (1.70+/-0.50) mm, the maxillary second premolars was (1.24+/-0.45) mm, and for maxillary first molars, the result was (0.83+/-0.40) mm. The difference between each result was statistically significant (P9< 0.01). The average vertical height of mandibular first premolars was (2.25+/-0.45) mm, the mandibular second premolars was (1.55+/-0.45) mm, and for mandibular first molars, the result was (1.18+/-0.40) mm. The difference between each result was statistically significant (P<0.0 1).</p><p><b>CONCLUSION</b>The vertical height of brackets position in posterior teeth should be considered to guarantee that mesio-distal marginal ridges of deferent posterior teeth located in the same plane, so that satisfying goal could be achieved, If the vertical height in the first molar was X mm, the vertical height in the second premolar should be (X+0.5) mm, and (X+1.0) mm might be suit for the first premolar.</p>

Orthodontic treatment of Class III patients with mandibular asymmetry / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the treatment outcome of Class III patients with dental, functional and mild skeletal mandibular asymmetry.</p><p><b>METHODS</b>Thirty-five patients (14 males and 21 females) with dental, functional and mild skeletal mandibular asymmetry were selected. The age range of the patients was 7 - 22 years with a mean age of 16.5 years. Dental mandibular asymmetry was treated with expansion of maxillary arch to help the mandible returning to normal position. Functional mandibular asymmetry was treated with activator or asymmetrical protraction and Class III elastics. Mild skeletal mandibular asymmetry was treated with camouflage treatment.</p><p><b>RESULTS</b>Good occlusal relationships were achieved and facial esthetics was greatly improved after orthodontic treatment in patients with dental and functional mandibular asymmetry. However, patients with skeletal mandibular asymmetry should be treated with both extraction and genioplasty.</p><p><b>CONCLUSIONS</b>Orthodontic treatment was suitable for patients with dental and functional mandibular asymmetry, while combined orthodontics and surgery could get good results in patients with skeletal mandibular asymmetry.</p>

Intrapentoneal chemotherapy for malignant ascites / 国外医学(肿瘤学分册)

The formation of malignant ascites is concerned with non-obstructive factors including immunity regulator(IL-2,TNF,IFN-?)and factors of inducing blood vessel penetrability(VEGF,MMP) besides obstructive factors. Intraperitoneal chemotherapy makes drug directly act on peritoneum and arrives at the aim of controlling and treating malignant ascites.

Effects of surface potentials of tooth hard tissue on bone remodeling in rabbit tibiae / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the influence of surface potentials of tooth hard tissue on bone remodeling.</p><p><b>METHODS</b>After insured the surface potentials of human extracted teeth with electrochemical methods, teeth sections and artificial hydroxyapatite were implanted into 25 rabbits' tibiae. The rabbits were sacrificed at 1, 2, 4, 6 and 8 weeks after implantation, respectively. The bone regeneration was compared between opposite two sides (cathode side and anode side) of tooth sections using hematoxylin-eosin (HE) staining, tartrate-resistant acid phosphatase (TRAP) activity detecting and tetracycline tracing method.</p><p><b>RESULTS</b>Resorption lacunae was seen in the tibiae facing to the enamel anode and new bone density in the implant bed near the cathode of tooth samples was much higher than that near the anode, while the number of TRAP positive cells near the cathode was smaller than that near the anode (P < 0.01). The fluorescent area of tetracycline tracing near the cathode was larger than that near the anode (P < 0.05).</p><p><b>CONCLUSIONS</b>The cathode of tooth hard tissue (cementum) could improve or trigger new bone formation, while the other side, anode (enamel), could improve the bone resorption. This study suggests that tooth hard tissue's electrochemical characteristic might affect the remodeling of alveolar bone, and tooth supraeruption and the alveolar bone loss after tooth extraction might result from the redundant or lack of root electrochemical stimulation to bone.</p>