Effects of Nd: YAG laser irradiation on the root surfaces and adhesion of Streptococcus mutans / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aimed to evaluate the effects of treatment with different powers of Nd: YAG laser irradiation on root surfaces and Streptococcus mutans (S. mutans) adhesion.</p><p><b>METHODS</b>Extracted teeth because of severe periodontal disease were divided into the following four groups: control group, laser group 1, laser group 2, and laser group 3. After scaling and root planning, laser group 1, laser group 2, and laser group 3 were separately treated with Nd: YAG laser irradiation (4/6/8 W, 60 s); however, the control group did not receive the treatment. Scanning electron microscopy (SEM) was used to determine the morphology. S. mutans were cultured with root slices from each group. Colony forming unit per mL (CFU·mL⁻¹) was used to count and compare the amounts of bacteria adhesion among groups. SEM was used to observe the difference of bacteria adhesion to root surfaces between control group (scaling) and laser group 2 (6 W, 60 s), thereby indicating the different bacteria adhesions because of different treatments.</p><p><b>RESULTS</b>Morphology alterations indicated that root surfaces in control group contain obvious smear layer, debris, and biofilm; whereas the root surfaces in laser group contain more cracks with less smear layer and debris. The bacteria counting indicated that S. mutans adhesion to laser group was weaker than that of control group (P<0.05). No statistical significance among the laser groups (P>0.05) was observed. Morphology alterations also verified that S. mutans adhesion to laser group 2 (6 W, 60 s) was weaker than that of control group (scaling).</p><p><b>CONCLUSIONS</b>This study demonstrated that Nd: YAG laser irradiation treatment after scaling can reduce smear layer, debris, and biofilm on the root surfaces as compared with conventional scaling. The laser treatment reduces the adhesion of S. mutans as well. However, Nd: YAG laser irradiation can cause cracks on the root surfaces. In this experiment, the optimum laser power of 6 W can thoroughly remove the smear layer and debris, as well as relatively improve the control of thermal damagee.</p>

A comparative study of two operations of sternal fracture / 中国医师进修杂志

Objective To compare the efficacies of the treatment of sternal fracture with wire fixation and the titanium sternal fixation system. Methods Thirty patients with sternal fracture from May 2003 to July 2009 were followed up. Among them,there were 20 patients with wire fixation (wire fixation group), 10 patients with the titanium sternal fixation system (titanium sternal fixation system group). The conditions before, during and after operation,complications and effects were compared to evaluate the effieaeies of titanium sternal fixation system. Results The operative time of titanium sternal fixation system group and wire fixation group were (67.0 ± 7.9) min and (90.0 ± 8.6) min, the blood loss were (11.0 ± 5.4) ml and (48.0 ± 8.4)ml,the duration of drainage were (0.5 ± 0.4) days and (1.9 ± 0.7) days,the amount of drainage were (1.9 ± 1.3) ml and (19.0 ± 4.6) ml, the average hospitalized days were (2.3 ± 0.5) days and (6.9 ± 0.9) days, the duration of pain were (1.5 ± 0.5) days and (3.8 ± 1.1) days, there were all significant difference between two groups (P < 0.05). The rates of wound infection, delayed union or nonunion, re-fracture,plate fracture or plate shift of wire fixation group were 5% (1/20) ,5% (1/20) ,5% (1/20), 10% (2/20). But the rates of titanium sternal fixation system group were 0, there were all significant difference between two groups (P < 0.05). Conclusion The treatment of sternal fracture with titanium sternal fixation system is a simple and stable fixation,high bone union rate and few complications,especially for the sternal fracture.