Haemostasis in Oral Surgery with Blue-Violet Light

Chemical, morphological and microhardness analysis of coronary dentin submitted to internal bleaching with hydrogen peroxide and violet LED

BACKGROUND

Violet LED has been used for internal bleaching, however its implications on coronary dentin composition are unclear. The present study aims to evaluate the effect of bleaching with violet LED, either associated with 35 % hydrogen peroxide or not, on microhardness, chemical composition, and morphological characteristics of coronal dentin.

METHODS

Thirty maxillary canines were selected to obtain 30 blocks of coronal dentin, distributed in 3 groups (n = 10): 35 % hydrogen peroxide (HP); violet LED (LED); HP 35 % + LED, (HP+LED). The chemical analysis was performed by FTIR and the morphological evaluation of the dentin structure by confocal laser scanning microscopy before (T0) and after treatment (T1). The microhardness analysis was performed by microdurometer after bleaching. The data were submitted to repeated measures ANOVA test (P> 0.05).

RESULTS

The intensity of the inorganic peaks decreased after bleaching for all groups (P = 0.003). There was an increase in the organic peak intensity after bleaching with HP, a decrease for LED, while HP+LED did not change the intensity (P = 0.044). Moreover, the inorganic/organic ratio decreased for HP (P = 0.022), while for LED and HP+LED there was no significant changes (P>0.05). HP and HP+LED showed lower microhardness values compared to LED (P< 0.05). Regarding morphological changes, an increase in the perimeter of the dentinal tubules was found for all groups, with the smallest increase being observed for LED.

CONCLUSION

HP bleaching decreased the chemical stability and microhardness of the coronal dentin, while the violet LED treatments had no significant impact on dentin stability. In all groups, there was an increase in exposure of the dentinal tubules after bleaching, which was less pronounced with the violet LED bleaching.

Histotopographic and morphometric characteristics of the oral mucosa postoperative wounds healing, depending on the method of connecting the wound edges

Implementation of high-quality tissue connections and hemostasis in oral surgery is an urgent problem of modern dentistry, due to the lack of available universal methods that would help to facilitate the work of oral surgeon and reduce wound healing time. The aim of the research. To investigate and study the regeneration processes in the oral mucosa after high-frequency electric welding, suturing and medical adhesive composition. Materials and methods. This study compared the effect of three connection methods and hemostasis: high-frequency electric welding (EKVZ-300M1 “PATONMED®”, Ukraine), suture method (nylon 5/0 “PIRUS®”, China), adhesive composition (“Histoacryl®”, Germany). 72 rabbits were involved in experiment. An incision of the soft tissues of the vestibulum of the oral cavity of the maxilla with a length of 1.3–1.5 cm was made. On days 3, 7, 14 and 21, tissue samples were excised, histological and morphometric examination of the material were performed. Results. By statistical data processing of 72 rabbits was found that the reliability of differences in the levels of morphometric parameters between groups on each day is very high, as evidenced by the calculated values ​​of the U-test. In 38 cases (90.5 %), the significance level was p≤0.01, in the other 4 cases – p≤0.05. The lowest value level of neutrophilic granulocytes was in rabbits of group No.1 (electric welding). In rabbits of group No. 1 GFBC were not observed in the 8 fields of view throughout the experiment. Conclusions. High-frequency electric welding of soft tissues can be used for effective intraoperative hemostasis and connection of the intraoral wound edges. Due to the absence of a foreign body (adhesive masses, filaments) and moderate alterative effect, histological examination indicates accelerated activation of regenerative processes in the early stages of observation in rabbits of group No. 1.

Under the spotlight: mechanisms of photobiomodulation concentrating on blue and green light

Photobiomodulation (PBM) describes the application of light at wavelengths ranging from 400-1100 nm to promote tissue healing, reduce inflammation and promote analgesia. Traditionally, red and near-infra red (NIR) light have been used therapeutically, however recent studies indicate that other wavelengths within the visible spectrum could prove beneficial including blue and green light. This review aims to evaluate the literature surrounding the potential therapeutic effects of PBM with particular emphasis on the effects of blue and green light. In particular focus is on the possible primary and secondary molecular mechanisms of PBM and also evaluation of the potential effective parameters for application both in vitro and in vivo. Studies have reported that PBM affects an array of molecular targets, including chromophores such as signalling molecules containing flavins and porphyrins as well as components of the electron transport chain. However, secondary mechanisms tend to converge on pathways induced by increases in reactive oxygen species (ROS) production. Systematic evaluation of the literature indicated 72% of publications reported beneficial effects of blue light and 75% reported therapeutic effects of green light. However, of the publications evaluating the effects of green light, reporting of treatment parameters was uneven with 41% failing to report irradiance (mW cm^-2) and 44% failing to report radiant exposure (J cm^-2). This review highlights the potential of PBM to exert broad effects on a range of different chromophores within the body, dependent upon the wavelength of light applied. Emphasis still remains on the need to report exposure and treatment parameters, as this will enable direct comparison between different studies and hence enable the determination of the full potential of PBM.