Objective To assess the effects of different application sequences of neodymium-doped yttrium aluminum garnet(Nd∶YAG)laser and the desensitizing toothpaste containing stannous fluoride on dentinal tubule occlusion.Methods Twelve intact third molars freshly extracted from human were selected and prepared into dentin slices with a thickness of 0.8 mm.Each dentin slice was subdivided into four small slices,three of which were etched with 6% citric acid and randomly assigned to the following three groups(n=12):(1)control group:no treatment;(2)Nd∶YAG+toothbrushing(TB)group:first irradiated with Nd∶YAG laser and then brushed with desensitizing toothpaste;(3)TB+Nd∶YAG group:first brushed with desensitizing toothpaste and then irradiated with Nd∶YAG laser.The Nd∶YAG laser irradiation were carried out at 1 W,15 pulses/s,and the pulse width of 150 μs for 10 s(for a total of 6 cycles).After the above treatment,the 12 dentin slices from the Nd∶YAG+TB and TB+Nd∶YAG groups were randomly assigned to four subgroups(n=3)and subjected to acid etching in the Coca-Cola solution for 0,5,10,and 15 min.A scanning electron microscope was used to observe and photograph the dentin slices in each group,and eight single-blinded examiners scored the slices according to uniform criteria.The analysis of variance was carried out to compared the scores between groups.Results Before acid etching,the dentin tubule occlusion scores of the Nd∶YAG+TB and TB+Nd∶YAG groups were(4.83±0.09) scores and(3.85±0.66) scores,respectively,which had no significant difference between each other(P=0.0590)and were higher than that[(0.10±0.07)scores]of the control group(both P<0.0001).The dentin tubule occlusion scores of the Nd∶YAG+TB group after acid etching for 5,10,and 15 min were(4.33±0.60)scores,(4.27±0.24)scores,and(3.63±0.07)scores,respectively,which were not significantly different from those[(4.04±0.10)scores,(3.76±0.59)scores,and(3.17±0.29)scores,respectively]of the TB+Nd∶YAG group(all P>0.05).In the Nd∶YAG+TB subgroup,the dentin tubule occlusion score after acid etching for 15 min was significantly lower than that before acid etching(P=0.0011).In the TB+Nd∶YAG group,there was no statistically significant difference in the score between before and after acid etching(P>0.05).Conclusions Nd∶YAG laser irradiation with appropriate parameters combined with the use of desensitizing toothpaste could produce an excellent occluding effect on dentinal tubules regardless of the sequence.However,brushing with desensitizing toothpaste followed by Nd∶YAG laser irradiation produced more consistent dentin sealing after acid etching.
Humans ; Dentin ; Dentin Sensitivity/therapy* ; Lasers, Solid-State/therapeutic use* ; Microscopy, Electron, Scanning ; Toothpastes/pharmacology*

OBJECTIVETo synthesize nano-hydroxyapatite (nano-HA) and evaluate its effect on the occlusion of dentinal tubules in vitro, and therefore provide evidence for the clinical application.

METHODS(NH(4))(2)HPO(4) and Ca(NO3)2 were used to form nano-HA, which was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FTIR) and X-ray diffractometer (XRD) respectively. Twenty-four dentin slabs were obtained from 8 healthy third molars and randomly divided into 3 groups, which were control group, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) group, and nano-HA group. After the CPP-ACP and nano-HA were topically applied to the slabs of two study groups twice a day for 7 days, the surface of slab dentin was observed using SEM.

RESULTSSEM, TEM, FTIR, and XRD tests showed that nano-HA was synthesized successfully. SEM observations revealed that the sealing of dentinal tubules of nano-HA group was extremely high when compared with those of control and CPP-ACP group.

CONCLUSIONSIn comparison with CPP-ACP, nano-HA could occlude dentinal tubules more effectively in vitro.

Caseins ; Dental Materials ; chemical synthesis ; Dentin ; Dentin Sensitivity ; therapy ; Durapatite ; chemical synthesis ; Humans ; Materials Testing ; Nanostructures ; Technology, Dental

PURPOSE: Dentin hypersensitivity is a potential threat to oral health. Laser irradiation may provide reliable and reproducible treatment but remains controversial. The present study aimed to evaluate the effects of CO2 or erbium-doped yttrium aluminium garnet (Er:YAG) laser therapy, and to assess mineral content. METHODS: Eighteen human single-rooted teeth affected with advanced periodontitis were obtained. Buccal and lingual surfaces were planed to form 36 specimens. Ethylenediaminetetraacetic acid gel (24%) was applied to remove the smear layer and simulate hypersensitive teeth. The experimental groups were: group 1, control (no irradiation); group 2, CO2 laser (repetitive pulsed mode, 2 W, 2.7 J/cm2); and group 3, Er:YAG laser (slight contact mode, 40 mJ/pulse and 10 Hz). To evaluate dentinal tubule occlusion, six specimens per group (2-mm thickness) were prepared and observed using scanning electron microscopy (SEM) for calculation of the occlusion percentage. To evaluate the mineral content, six specimens per group (0.6-mm thickness) were used, and then the levels of Ca, K, Mg, Na, and P were measured by inductively coupled plasma-atomic emission spectrometry. In addition, the surface temperature of the specimens during laser irradiation was analyzed by a thermograph. RESULTS: The SEM photomicrographs indicated melted areas around exposed dentinal tubules and a significantly greater percentage of tubular occlusion in the CO2 and Er:YAG laser groups than the control, and in the Er:YAG group than the CO2 laser group. In addition, no significant differences were noted among the experimental groups for the mineral elements analyzed. The CO2 laser group showed an evident thermal effect compared to the Er:YAG group. CONCLUSIONS: CO2 and Er:YAG laser are effective in treating dentin hypersensitivity and reducing its symptoms. However, the Er:YAG laser has a more significant effect; thus, it may constitute a useful conditioning item. Furthermore, neither CO2 nor Er:YAG lasers affected the compositional structure of the mineral content.
Dentin ; Dentin Sensitivity* ; Edetic Acid ; Humans ; Hypersensitivity ; Laser Therapy* ; Lasers, Gas ; Microscopy, Electron, Scanning ; Minerals ; Oral Health ; Periodontitis ; Smear Layer ; Spectrum Analysis ; Tooth ; Yttrium*

OBJECTIVEThis study aims to assess the effects of desensitizing toothpaste containing stannous fluoride on dentine hypersensitivity by performing Meta-analysis of randomized controlled trials (RCT) involving the treatment of dentine hypersensitivity with stannous fluoride-containing toothpaste.

METHODSThe study was developed based on the Cochrane handbook for systematic reviews of interventions (Version 5.1.0) and included the following: search strategy, selection criteria, data extraction, and risk of bias assessment. We searched electronic databases such as CNKI, CBM, PubMed, Embase, and Cochrane Library up to January 2015. RCT of treating dentine hypersensitivity with stannous fluoride-containing toothpaste were included. Data extraction and domain-based risk of bias assessment were independently performed by two reviewers. Meta-analysis was performed with RevMan 5.3 software.

RESULTSSix RCT with 494 patients (247 in the experimental group and 247 in the control group) were included. The results of Meta-analysis showed that the desensitizing effect of stannous fluoride-containing toothpaste was significantly better than that of control in tactile sensitivity test (SMD=1.41, 95% confidence interval 0.74-2.09, P<0.00001) and air blast test (SMD = -1.16, 95% confidence interval -1.84--0.48, P<0.000 01).

CONCLUSIONCurrent evidence shows that stannous fluoride-containing toothpaste is effective in treating dentine hypersensitivity in clinic. However, due to limited sample size and lower quality of the included studies, more high quality and large-sample RCT are needed to further verify the evidence.

Dentin Desensitizing Agents ; therapeutic use ; Dentin Sensitivity ; drug therapy ; Humans ; Randomized Controlled Trials as Topic ; Sodium Fluoride ; Tin Fluorides ; therapeutic use ; Toothpastes ; therapeutic use ; Treatment Outcome