| Backgrounds and ObjectiveDentin allergies are common dental diseases and its treatment is numerous,but the curative effects are different and unsatisfactory.Currently,pulse Er:YAG laser which is used for the treatment of dentin allergy is a new kind of method while the application in clinical specific energy,application of theoretical basis and clinical effect evaluation restrict the extensive application of the method,so it remains to be solved.This research discusses the energy parameters setting for the using of Er:YAG laser,dentin molten changing,dentin tubule closing situation and the clinical effect of sodium fluoride treatment combined with laser for the treatment of dentin allergies through the three part of teeth in vitro experiment,animal experiment and clinical practical research,then provide the basis for the clinically effective application of Er:YAG laser.Materials and methods1 Teeth in vitro experiment1.1 Collecting 26 complete premolars without decay which were taked from orthodontic whose age were between 10 and 35 and get the dentin block which were cuted to four arround the medullary cavity.Randomly taked 2 teeth as blank control group(C group),and the rest of 24 teeth were randomly divided into group A(Er: YAG laser exposured for 10 s)and group B(Er: YAG laser exposured for 20 s),then they were randomly divided into six groups according to the above the used different laser power(including 1,2,3,4,5,and 6 W).The A,B two groups were exposured with Er: YAG laser,and C group undergo the condition of simulated above all operations of the implementation of A and B group while the laser power supply was cutted.Measured the dentine diameter and depth with SEM observation.1.2 Collect 14 premolars with the above requirements.Randomly taked 2 teeth as blank control group(C group),and the rest of 12 teeth were randomly divided into group A(Er: YAG laser exposured for 10 s)and group B(Er: YAG laser exposured for 20 s),then they were randomly divided into three groups according to the above the used different laser power(including 1,2,3 W).Measured the dentin tubule diameter,density,and the relative area after the irradiation.1.3 Collect 8 premolar with the above requirements.Randomly taked 2 teeth as blank control group(D group),the rest of the 6 teeth were randomly divided into group A(surface of the paste with 75% Na F glycerine)and group B(20 Hz 3 W Er: YAG laser irradiation 20 s)and group C(surface of the paste with 75% NaF glycerine combined the 20 Hz 3 W Er: YAG laser irradiation 20 s),then Measured the dentin tubule diameter,density,and the relative area after the irradiation.2 Clinical studies114 patients with dentin allergies accepted treatment in our hospital from September 2012 to November 2012 were selected and they were randomly divided to A group 55 cases including 122 sick teeth,B group 32 cases including 61 sick teeth and C group 27 cases including 55 sick teeth.A group were treated with Er:YAG laser combined with NaF treatment,B group with Er:YAG laser treatment,and C group with Na F therapy alone while the Er:YAG laser output power is fixed in the 3 W.Give each tooth 15 s irradiation,and check and record the patient’s individual tooth sensitivity in different times.Result1 Teeth in vitro experiment1.1 With the increase of laser power and irradiation time,the dentin pit diameter and depth increase constantly,and they does not change significantly under high power,there is significantly statistical difference under the irradiation of low power and high power(P < 0.05).A,B groups in the same irradiation time and different irradiation power were statistically significant(P < 0.05).After 10 s irradiation of Er: YAG laser,the dentin melting change appears,and the dentin tubule closes well while these changes were more significant with the increase of irradiation power.When the irradiation power power reaches 5 W,the dentin pits and bumps began to appear accidental cracks and were divided into many small pieces.1.2 With the Er: YAG laser power and irradiation time increases,the diameter,density and relative area of the dentin tubule decreased in succession(P < 0.05);the diameter,density and relative area of the dentin tubule in A,B groups were obviously lower than those in group C(P < 0.05);the diameter,density and relative area of the dentin tubule in B group were obviously lower than those in A and C groups(P < 0.05);the diameter,density and relative area of the dentin tubule of A,B groups in the same irradiation time and different irradiation power were statistically significant(P < 0.05),and the higher the performance of power,the smaller the diameter,density and relative area of the dentin tubule(P < 0.05).1.3 The diameter,density and relative area of the dentin tubules which were treated with Er:YAG laser combined Na F were significantly less than those in the blank control group,individual by NaF and Er: YAG laser treatment group(P < 0.05).2 clinical researchThe curative effect of immediately and 3 d,7 d,30 d after the treatment in group A were significantly better than those in group B and C(P < 0.05);Just as the extension of time after treatment,the curative effect of all patients showed decline,but the treatment effcet of Er:YAG laser combined NaF was better.Conclusion1.With the Er: YAG laser ultrashort pulse of 20 Hz frequency,power of 1 W to 3 W,irradiation time within 20 s,dentin molten changes obviously,dentin tubule closed without craze damaging,so it provide safe and reliable basis for clinical using.2.After Er: YAG laser combined sodium fluoride(Na F),it can be better sealed dentin tubule and dentin surface flat,and proved that adding with NaF can complement the laser dentine missing Ca2+ and F-elements,enhance the acid and corrosion resistance,and extend the desensitization treatment effect.3.The Er: YAG laser combined NaF treatment,Er: YAG laser treatment and NaF treatment all showed good effects,but the treatment effcet of Er: YAG laser combined Na F was better along with the extension of time after treatment. |
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