The Biological Effects Of The Laser On The Pulp Tissue And Cell

The pulp injury model is an important method to investigate the pulp damage repairmode. To investigate the different inflammatory reaction in pulp, we must establish amodel of pulp injury model, and experiments are performed on the model that we establish.However, each animal, being different, has its own characteristics. The conventionaldental pulp injury model needs to destroy the tooth structure. Establishment of a unifiedmodel can’t be guaranteed in a number of animals. Thus, whether we can create a trulyparallel comparative pulp injury model?Laser is a quantification and fixed energy source, has been widely used in clinical,such as dental and Periodontal disease. With the developing of research and application inlaser, the biological effects of more and more people are concerned about. A large numberof studies have revealed that there are biological effects in the different tissue with the same energy and the same tissue with the different energy.Whether the laser energy is a key determine the mode of pulp injury. Using differentlaser energy induces the pulp to produce the unique biological effect, with establishingcontrollable pulp damage repair model.There are two parts in this study. The first part, in vivo, preliminarily studies therelationship between laser energy and inflammatory reaction. The second part, in vitro,Observe the laser impact on the OLCs’ biological functions cultured in vitro.Part I The biological effects of the semiconductor (Ga-Al-As) laser with differentdose on the Rat’s pulp tissueExperiment1：The Anatomical changes of the semiconductor (Ga-Al-As) laser withdifferent dose on rat tooth morphologyIn this experiment, the rat incisor were lased at an output power of0w.0.5w,1.0w,1.5w for500ms pulsed,180s and1.5w,3.0w for0pulsed,90s. After different energyirradiation, dental and periodontal tissue reactions were observed. The Result revealedthere was more obvious damage with Continuous laser irradiation pattern. Furthermore,Tooth structure showed obvious damage. Periodontal also showed different inflammatorychanges.3.0w laser energy effect is very obvious. Gingival pyorrhea and Tooth breakingwere observed.In pulsed laser irradiation pattern. The experiment revealed1.0w,1.5w for500ms pulsed,180s could induce gum tissue congestive and hydropic.however, we can’tfind damage in Tooth structure.Experiment2：The Pathological effects of the semiconductor (Ga-Al-As) laser withdifferent dose on the Rat’s pulp tissueIn this experiment，the study aimed to observe the pathological effects in pulp tissue.There were more obvious changes in Continuous laser irradiation pattern, and the changeswere not limited to the irradiation point. The irradiated pulp showed different degrees ofinflammatory changes. There is a large area of coagulation necrosis in this pulp. In pulsedlaser irradiation pattern. There is no obvious area of coagulation necrosis. Mild inflammatory changes can be observed. An obviously limited area of coagulation necrosiswas observed in1.0w,500ms,180s mode. In1.5w,500ms,180s mode, there was moreobvious coagulation necrosis, and the area was larger than that in other pulsed groups. Thepulp tissue of gingival direction had more pathological changes. Combined with the resultof experimental1,1.0w,500ms,180s irradiation parameters used to establish in the ratdental pulp damage repair model.Experiment3：The gene expression change of the semiconductor (Ga-Al-As) laser onthe Rat’s pulp tissueBased on the past two Experiments, the study aimed to investigate the geneexpression with1.0w500ms,180s irradiation parameter. At last, the result revealed thatNo irreversible pulpitis was detected in the dental rat’s pulp after laser irradiation with1.0w,180s,500ms pulse mode. And what’s more, the mineralization was activated after7days of laser irradiation. Furthermore, after14days, the expression of DMP1mRNA indental pulp compared with the control group and was time-dependently increased. In thisstudy, the biological effects of this parameter son rat’s pulp were study further. Laserinduced inflammation in rat dental pulp tissue. Pulp had self-Repair behavior. It meetedthe basic requirements for the establishment of pulp damage repair model.Part II The biological effects of the semiconductor (Ga-Al-As) laser with differentdose on the pulp cell in vitroExperiment1: the Effect of the semiconductor (Ga-Al-As) laser with different doseon the Proliferation of OLCsThe study aim to investigate the Effect of the different semiconductor (Ga-Al-As)laser on the Proliferation of OLCs, and what’s more, cell morphology was observed undera microscope. The result revealed that the laser which is in this study has no Effect on theProliferation of OLCs, and there is no different cell morphology between the experimentalgroups and control group.Experiment2: the Effect of the semiconductor (Ga-Al-As) laser with different dose on the mineralization of OLCsThe parameters were same as Experiment1. The mineralization of OLCs wasobserved by staining and real-time PCR. At last, that result indicated the promotableEffect of the semiconductor (Ga-Al-As) laser on the mineralization of OLCs and there wasdifference between the experimental groups in Different period. In the2days after themineralization of OLCs, The expression of DMP1mRNA in dental pulp compared withthe control group and was time-dependently increased. Furthermore, the effect of thelower energy was more obvious. However, after7days, the effect of the higher energy wasmore obvious significant. By observed the alizarin red stain after mineralization21days,compared the between the experimental groups with control group. The result indicatedthat the Alizarin red stain of the experimental groups was more average and obvious thanthe control group, but there was no difference in the experimental groups.