OBJECTIVES: The purpose of the study was to evaluate the effect of hydroxyapatite (HA)-based desensiti-zing agents and determine their influence on the bonding performance of mild universal adhesives. METHODS: Mid-coronal dentin samples were sectioned from human third molars and prepared for a dentin-sensitive model. According to desensitizing applications, they were randomly divided into four groups for the following treatments: no desensitizing treatment (control), Biorepair toothpaste (HA-based desensitizing toothpaste) treatment, Dontodent toothpaste (HA-based desensitizing toothpaste) treatment, and HA paste treatment. Dentin tubular occlusion and occluded area ratios were evaluated by scanning electron microscopy (SEM). Furthermore, All-Bond Universal, Single Bond Universal, and Clearfil Universal Bond were applied to the desensitized dentin in self-etch mode. The wettability and surface free energy (SFE) of desensitized dentin were evaluated by contact angle measurements. Bonded specimens were sectioned into beams and tested for micro-tensile bond strength to analyze the effect of desensitizing treatment on the bond strength to dentin of universal adhesives. RESULTS: SEM revealed that the dentin tubule was occluded by HA-based desensitizing agents, and the area ratios for the occluded dentin tubules were in the following order: HA group>Biorepair group>Dontodent group (P<0.05). Contact angle analysis demonstrated that HA-based desensitizing agents had no statistically significant influence on the wettability of the universal adhesives (P>0.05). The SFE of dentin significantly increased after treatment by HA-based desensitizing agents (P<0.05). The micro-tensile bond strength test showed that HA-based desensitizing toothpastes always decreased the μTBS values (P<0.05), whereas the HA paste group presented similar bond strength to the control group (P>0.05), irrespective of universal adhesive types. CONCLUSIONS HA-based desensitizing agents can occlude the exposed dentinal tubules on sensitive dentin. When mild and ultra-mild universal adhesives were used for subsequent resin restoration, the bond strength was reduced by HA-based desensitizing toothpastes, whereas the pure HA paste had no adverse effect on bond strength.
Humans ; Dental Cements/analysis* ; Dentin/chemistry* ; Durapatite/pharmacology* ; Tensile Strength ; Toothpastes

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*

OBJECTIVE: To explore the effects of three dentine desensitizers on the surface morphology of freshly exposed dentin and to evaluate their occlusion effects on dentinal tubules using scanning electron microscope (SEM). METHODS: A total of 16 isolated human premolar samples, which were prepared to expose dentine, were randomly divided into a control group (n=4), a Hybrid Coat group (n=4), a Prime & Bond NT group (n=4), and a anti-sensitivity toothpaste group (n=4). After treatment with dentine desensitizers, one half of the samples in each group were vertically cleaved. Finally, the surfaces and cross sections of the samples were observed by SEM. RESULTS: The exposed tubule was almost occluded in the Hybrid Coat group and the Prime & Bond NT group, while only the majority of tubules could be sealed in the anti-sensitivity toothpaste group. The cross-section images showed that sediments were visible in all groups except the control group. CONCLUSION Hybrid Coat and Prime & Bond NT are able to effectively seal tubules, while the effect of anti-sensitivity toothpaste is slightly poor.
Dentin ; ultrastructure ; Dentin Desensitizing Agents ; pharmacology ; Dentin Permeability ; drug effects ; Humans ; Microscopy, Electron, Scanning ; Polymethacrylic Acids ; pharmacology ; Toothpastes ; pharmacology

OBJECTIVETo formulate the standard measuring tool for the evaluations on fire-heat syndrome in oral cavity by means of Chinese medicine (CM).

METHODSThe measuring scale for fire-heat syndrome in the oral cavity by means of CM was investigated by symptom collection, item pool formulation, item selection, pre-investigation, evaluations on the reliability, validity and reactivity of the measuring scale, according to the principles for measuring scale design and under the guidance of CM theories.

RESULTSThe measuring scale was composed of two integrative parts: the self-filling section and the interview section. As far as the reliability was concerned, the total Cronbach α coefficient of the measuring scale was 0.866, the total test-retest reliability coefficient was 0.726 and the split-half reliability coefficient was 0.851. As far as the validity was concerned, the scores for the subjects of fire-heat syndrome in oral cavity and healthy people in their oral cavity in the items of symptoms were statistically different (P<0.01); three common divisors were extracted according to the theoretical dimensions, the accumulated contribution rate was 63.468%. As far as the reactivity was concerned, the difference between the symptom scores before and after the test in which 31 subjects used the Chinese herb toothpaste was statistically significant (P<0.01).

CONCLUSIONSThis measuring scale has relatively good reliability, validity and reactivity, and it can be used in an objective quantitative evaluation on patients suffering from fire-heat syndrome in oral cavity, and thus lay the foundations for the evaluations on the therapeutic effects of Chinese herb toothpaste on fire-heat syndrome in oral cavity.

Drugs, Chinese Herbal ; pharmacology ; Evaluation Studies as Topic ; Humans ; Mouth ; drug effects ; pathology ; Statistics as Topic ; Surveys and Questionnaires ; Syndrome ; Tooth ; drug effects ; Toothpastes ; pharmacology