# Effectiveness of Laser-Assisted Teeth Bleaching: A Systematic Review
## 3 Results
### General Characteristics of the Included Studies
#### 3.2.5 Potassium Titanyl Phosphate (KTP) Laser-Assisted Bleaching  
There was a dissonance between researchers using the KTP laser. According to some studies, the effects are more visible compared to the diode laser, but the results of others indicate that there is no statistically significant difference between them [48; 52]. [PERSON] et al. [53] point out the difference in action against specific discolorations. In their study comparing the effects of diode laser-assisted whitening and KTP, he showed that both lasers could remove coffee stains, while enamel stains caused by fruit and tea were only removed by using the KTP laser and not the diode laser [53]. 2.6 Erbium/Yttrium-Aluminum-Garnet (Er:YAG) and Erbium, Chromium, Yttrium, Scandium, Gallium Garnet (Er,Cr:YSGG) Laser-Assisted Bleaching  
Whitening with the assistance of an Er:YAG laser led to a change in the color of the enamel comparable to that achieved with a diode laser, but required twice the exposure time [55]. When applied to endodontically treated teeth, the Er:YAG laser provided a more favorable effect than the walking bleaching method, although this was only observed with the use of 20% HP [64]. Both [PERSON] et al. [10] and [PERSON] et al. [55] prove, with their research, the effectiveness of Er,Cr:YSGG laser whitening. They both used 35% HP and the same laser parameters for this purpose. [PERSON] additionally compared the power of 1.25 W and 2.5 W, while [PERSON] reduced the exposure time from 30 to 15 s. In each case, whitening was more effective than conventional methods. However, this does not work in the case of composite fillings. In this case, the obtained color did not differ from the initial one [8] (see Table 1). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Study** & **Aim of the Study** & **Material and Methods** & **Results** & **Conclusions** \\ \hline \hline \multirow{8}{*}{Guedes RA [3]} & \multirow{8}{*}{ \begin{tabular}{c} Bleaching treatment \\ using 37\% carbamide \\ peroxide combined \\ with hybrid light and \\ TiO\({}_{2}\) increases the \\ effectiveness of the \\ change in color of the \\ dental surface. \\ \end{tabular}  } & Fifty bovine incisors were divided into 5 groups and exposed to 35\% hydrogen peroxide, 37\% urea peroxide, urea peroxide, urea peroxide, urea peroxide + 1\% TiO\({}_{2}\) and urea peroxide + 1\% TiO\({}_{2}\) and urea peroxide + 1\% TiO\({}_{2}\) + 1\% TiO\({}_{2}\) + 1\% TiO\({}_{2}\) + 1\% TiO\({}_{2}\) + 1\% TiO\({}_{2}\) + 1\% TiO\({}_{2}\) + 1\% TiO\({}_{2}\) + 1\% TiO\({}_{2}\) + hybrid light, urea peroxide + 1\% TiO\({}_{2}\) + hybrid light. & The greatest color changes for \(\Delta\)Eab were observed after bleaching with urea peroxide + 1\% TiO\({}_{2}\) + hybrid light. & A whitening gel containing carbamide peroxide combined as well as urea peroxide combined with TiO\({}_{2}\) and hybrid light increases \\ \cline{1-1} \cline{2-5}  & & Thirty samples were made from Filttek Bulk Fill, FiltektTM Z550 XT & The greatest color change was observed in restorations made with FittektTM Z350 Xt & Bleaching caused a slight change in the color of the composite materials and their \\ \cline{1-1} \cline{2-5}  & The effect of 940 nm diode laser-activated & FittektTM Z350 Xt & \begin{tabular}{c} The greatest color change was observed \\ in restorations made \\ with FittektTM Z350 Xt \\ \end{tabular}  & \begin{tabular}{c} The greatest color change was observed \\ in restorations made \\ with FittektTM Z350 Xt \\ \end{tabular}  & \ \begin{tabular}{c} The partial and their \\ roughness. Bleaching \\ can cause a loss of \\ bonding between the \\ composite molecules \\ and lead to the \\ increased release of \\ toxic monomers. \\ \end{tabular}  \\ \hline \multirow{8}{*}{Vochikovski L [1]} & \multirow{8}{*}{ \begin{tabular}{c} Evaluation of \\ photobiomodulation in \\ reducing tooth \\ sensitivity after \\ in-office bleaching. \\ \end{tabular}  } & Patients were divided into a control group that received only 1 whitening session and an experimental group.