In vivo efficacy of low-level laser therapy on bone regeneration.

PURPOSE: In clinical use of low-level laser therapy for bone regeneration (LLLT), application protocol (dose, duration, and repetitions) has not been established. This study aimed to depict a reliable dosage of LLLT by evaluating the efficacy of different dosing of LLLT (diode) on the healing of rabbit cranial defects. METHODS: Critical size defects were prepared in calvarias of 26 New Zealand White Rabbits in such each animal containing both test and control groups. Test groups were irradiated with 4 Joule/cm2 (j/cm2), 6 j/cm2, and 8 j/cm2. The rabbits were subjected to six times of laser treatments in 10 days. At the end of the second week, 5 rabbits were sacrificed for histopathological and immunohistochemical analyses. At the 4th and 8th weeks, 20 rabbits (10 each) were sacrificed for micro-CT and histopathological analyses. RESULTS: Micro-CT evaluation revealed improved new bone formation in all test groups compared to the control group. 6 j/cm2 group demonstrated the highest bone formation. The highest bone morphogenic protein -2 levels were found in the 4 j/cm2 group. Osteocalcin expression was significantly higher in 4 j/cm2 group. CONCLUSIONS: Our findings indicate that LLLT have a positive effect on new bone formation. The high efficacy of doses of 4 j/cm2 and 6 j/cm2 is promising to promote early bone healing.

The effect of bleaching systems on the gingiva and the levels of IL-1ß and IL-10 in gingival crevicular fluid.

OBJECTIVE: This study aimed to evaluate the color change and clinical periodontal parameters and to analyze the interleukin­1 beta (IL-1ß) and interleukin-10 (IL-10) levels in gingival crevicular fluid (GCF) of patients treated with different bleaching systems. MATERIALS AND METHODS: According to pre-established criteria, 30 healthy volunteers were selected and randomly divided into three groups (n=10): G1, home bleaching (Opalescence 35% Carbamide Peroxide, CP); G2, chemically activated office bleaching (Opalescence Xtra Boost 38% Hydrogen Peroxide, HP); G3, light-activated office bleaching (Opalescence Xtra 35% HP). Treatments were applied according to the manufacturer's recommendations. After shade evaluation, clinical periodontal parameters were evaluated as follows: gingival index (GI), plaque index (PI), and bleeding on probing (BOP). GCF were collected from six maxillary sites per patient at baseline (T0), one day (T1) after bleaching treatments, and 15 days (T2) after bleaching treatments and analyzed for IL-1ß and IL-10 by enzyme-linked immunosorbent assay. Data were subjected to statistical analysis (p<0.05). RESULTS: Spectrophotometer readings exhibited significant differences among the groups (p<0.05). The ΔE values (color change) of G3 were statistically higher than the other groups (p<0.05). The PI of G3 after 15 days was significantly higher than the PI of G2 after 15 days (p<0.05). The GI of G2 was lower than that of G1 and G3 before bleaching (p<0.05). According to BOP, no significant differences were found among the groups at any time intervals (p>0.05). In G3, the total amount of IL-1ß after 15 days was higher than the amount before bleaching (p<0.05). The IL-10 total amount and concentration levels did not exhibit any significant differences among the groups or by time (p>0.05). CONCLUSION: Home and chemically activated bleaching systems could be considered as safer in tooth whitening and maintaining gingival health when compared with a light-activated bleaching system, which might lead to increased proinflammatory cytokine (IL-1ß).

Interleukin-11, interleukin-1beta, interleukin-12 and the pathogenesis of inflammatory periodontal diseases.

OBJECTIVES: The balance between pro-inflammatory and anti-inflammatory cytokines may be crucial for determining the immunopathology of gingivitis (G) and periodontitis. This study aimed to analyse interleukin-1beta (IL-1beta), IL-11 and IL-12 levels in gingival crevicular fluid (GCF) of patients with G and chronic periodontitis (CP). MATERIAL AND METHODS: Fourty subjects including 12 CP, 14 G and 14 controls (C) were enrolled. GCF samples were collected from six maxillary sites per patient and analysed for IL-1beta, IL-11 and IL-12 by an enzyme-linked immunosorbent assay. RESULTS: Significantly lower concentrations of IL-11 were detected in CP compared with both G and C groups (p<0.05). The CP group had a significantly higher total amount of IL-12 and IL-1beta compared with the C group (p<0.05). The IL-11:IL-1beta cytokine ratio was higher in both G and C groups compared with the CP group. The IL-11:IL-1beta ratio became progressively lower with increasing probing depth (p<0.01). CONCLUSIONS: Our data showed that IL-11 levels are significantly decreased in GCF from sites with periodontitis compared with G and healthy sites. Because of the possible preventive effect of IL-11 on inflammation, IL-11 may be an important factor in the therapeutic modulation of periodontal disease.