The Effect of Ytterbium-Doped Fiber Laser with Different Parameters on Physical Properties of Zirconia Surface

OBJECTIVE

Laser irradiation is an alternative surface treatment method for roughening zirconia surfaces. The aim of this study was to evaluate the effects of ytterbium-doped fiber laser (YbPL) on zirconia.

BACKGROUND

Zirconia surfaces are resistant to many surface treatment methods, but surface roughness is crucial for adhesion of veneering materials and cements to zirconia.

METHODS

The zirconia discs were prepared and divided into four groups according to the power of the laser irradiation (5, 12, 17, and 20 W). These groups were divided into five subgroups according to the frequency (25, 40, 60, 80, and 100 kHz). Surface roughness values were measured with a noncontact profilometer, and the mean Ra values were calculated. Wettability was measured with a goniometer. The surface morphology was observed with a scanning electron microscope (SEM). The changes in the surface crystalline structure were analyzed with X-ray diffractometry.

RESULTS

Ra values of all groups were higher than the control group. The highest surface roughness value was at 20 W and 100 kHz. Best wettability characteristic was observed at 5 W and 60 kHz. The correlations between Ra and wettability were low but significant. SEM examination of 5 W with different frequencies showed no microcracks, however, melted areas were observed. Remaining groups had microcracks and melted layers. A significantly lower T/M-phase transformation was observed in some groups.

CONCLUSIONS

YbPL irradiation was effective at roughening the zirconia surface. Although laser treatment affected zirconia surfaces and provided surface roughness, the power and frequency should be adjusted to achieve optimum results.

Salivary IL-6 and IL-10 levels in subjects with obesity and gingivitis

PURPOSE

To evaluate the association between cytokines IL-6 and IL-10 in saliva, obesity and periodontal disease.

METHODS

The study was carried out in 40 subjects: 20 obese subjects with gingivitis and 20 non-obese subjects with gingivitis (controls). Periodontal parameters such as gingival index (GI) and plaque index (PI) of subjects were recorded. Saliva samples were used for measuring IL-6 and IL-10 levels by ELISA method.

RESULTS

Saliva IL-6 levels were significantly higher in obese subjects than those of non-obese subjects (P= 0.002). When total groups were evaluated, negative significant correlation between GI and salivary IL-10 levels (r= -0.452, P= 0.003) and positive correlations between salivary IL-6 level and body mass index (BMI) (r= 0.369, P= 0.019) were found. There was a negative correlation between the GI and salivary IL-10 levels in obese subjects (r= -0.548, P= 0.012). Also there was a positive correlation between the salivary level of IL-6 and IL-10 in obese subjects (r= 0.594, P= 0.006).

CLINICAL SIGNIFICANCE

Obesity and adipose tissues can affect periodontal health by altering the levels of IL-6 and IL-10. IL-6 in saliva clearly increased in subjects with obesity compared to subjects without obesity. Also negative correlations between saliva IL-10 levels and GI were found in the total group and obese subjects.

Mandibular bone mineral density in patients with Behçet's disease

OBJECTIVES

Behçet's disease (BD) is a chronic, recurring vasculitis of unknown etiology. Patients with BD may use a lot of medications associated with the clinical symptoms. Drugs that are used in the treatment of BD may cause bone loss. The aims of the current study were to compare the bone mineral density (BMD) values between BD and healthy volunteers and describe the effect of disease duration on mandibular BMD.

MATERIALS AND METHODS

The study comprised 30 healthy volunteers (15 males and 15 females, mean age 35.50±6.80 years) and 45 patients with BD (24 males and 21 females, mean age 38.93±8.93 years). The BD group was subdivided according to disease duration (0-5, 6-10, and >10 years). The BMD value of the mandibular body was determined by the dual energy X-ray absorptiometry technique.

RESULTS

The mean mandibular body BMD values were 1.294±0.21 g/cm(2) in the control group and 1.216±0.22 g/cm(2) in the BD patients, although there was no statistically significant difference. The BMD was observed to decrease with increased disease duration but not to a statistically significant degree.

CONCLUSION

The results of this study showed that although the BMD value decreased as the duration of the disease increased, no statistically significant difference was found between the BD patients and the healthy control group.