Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Dentin Permeability”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources
PubMed1991

Dentinal permeability of the dog canine after exposure of a cervical cavity to the beam of a CO2 laser.

The dentinal permeability of the axial wall of a class V cavities in the canine of the dog was analyzed before and after its laser CO2 irradiation at two energy levels: 285 J per cm2 and 570 J per cm2. The sealing of the exposed dentin was verified by means of a pellet of cotton wool placed in contact with the axial wall and on which 20 microliters of a 50 mg per ml solution of noradrenaline was injected with a micrometric syringe. The transdentinal passage of noradrenaline induces a vasoconstriction of the pulp which is attested by a drop in its blood pressure. The absence of any variation in the pulpal pressure is an indication of the sealing to noradrenaline of the dentinal wall irradiated with an energy level of 570 J per cm2. This experimentation illustrates that it is possible to obtain dentinal sealing by means of laser irradiation without affecting the underlying pulp. The quality of this reduction in permeability is dependent upon the different factors which define the energy level.

Animals↗
PubMed1991

Dentin permeability and restorative dentistry: a status report for the American Journal of Dentistry.

Most dental materials permit of microleakage because oral fluids and bacteria commonly gain access to dentin surfaces. Dentin is permeable and allows the bidirectional movement of materials from the oral cavity, across dentin to the pulp and vice versa. The pupal irritation associated with microleakage is often dictated by the permeability of dentin. Thick dentin covered with a smear layer is a better barrier than thin dentin with the smear layer removed, while coronal dentin is more permeable than root dentin. Carious dentin is less permeable than normal dentin, but freshly cut dentin is more permeable than previously prepared dentin. This is partly due to the movement of large plasma proteins from the pulpal blood vessels into dentin. The pulpal circulation contributes to the health of the pulp by supplying nutrients and by removing toxic material that diffuses across dentin via the microcirculation. Thus, there is a delicate balance involving the rate bacterial products diffuse around microgaps between restorative materials and dentin, the rate these materials permeate across dentin and the rate they are removed during pulpal circulation.

Dental Leakage↗
PubMed1991

The effects of storage after extraction of the teeth on human dentine permeability in vitro.

Freshly extracted third molars were stored for one week in one of four solutions: 70% ethanol, 10% formalin, distilled water with thymol and phosphate-buffered saline with thymol. Crown segments were prepared and initial permeability measurements taken. Each specimen was placed in a fresh preparation of its original solution, and permeability was measured over two periods: 1, 4, 6 and 8 days or 1, 8, 15 and 22 days. Ten crown segments were used for each solution for each time sequence. Permeabilities were lower for those specimens stored in ethanol and formalin than in water/thymol and saline/thymol, but most specimens showed increased permeability with time. Both storage solution and storage time had statistically significant effects (p less than 0.05), with significant differences between specimens stored in water/thymol and saline/thymol and those stored in ethanol and formalin. Thus, type of storage solution effects dentine permeability over time.

Analysis of Variance↗
PubMed1998

Effects of desensitizing agents on human dentin permeability.

PURPOSE: To compare the in vitro effects of three desensitizing agents on hydraulic conductance of human dentin: Protect (n = 10), Gluma Desensitizer (n = 10), MS Coat (n = 10) (Pain-Free in the USA). MATERIALS AND METHODS: Dentin discs were prepared from 40 freshly extracted normal human third molars. The pulpal side of the dentin discs was etched with 37% phosphoric acid for 15 s and then rinsed under tap water. The coronal side was sequentially ground and the dentin discs were sonicated for 30 min. The hydraulic conductance was measured filtering 20% serum in phosphate buffered saline under a pressure of 15 cm H2O. The hydraulic conductance of each dentin specimen was measured before using the desensitizing agent and this value was designated as 100%. Thirty dentin discs were treated, the hydraulic conductance was remeasured and expressed as a percentage of the hydraulic conductance of that specimen before treatment. The teeth were stored for 1 month at 37 degrees C in deionized water and the hydraulic conductance of the 40 dentin discs was recorded again. Ten dentin discs were left untreated to serve as a control. RESULTS: No statistical difference was found between the immediate hydraulic conductance of the three groups after treatment. After 1-month storage, the control group showed a statistically higher hydraulic conductance than the three treated groups. There was no statistical difference between the three dentin desensitizing agents evaluated.

Acid Etching, Dental↗
PubMed1999

Dentine permeability and tracer tests.

OBJECTIVES: This paper reviews the evidence for dentine's permeability in order to clarify and emphasize its confounding effect on leakage test measurements, and hence the need to use special test designs to avoid its effects. METHODS: The literature on the subject between 1887 and 1997, including 249 articles. CONCLUSIONS: The prerequisite condition for any tracer penetration test is that unflawed specimens are themselves impermeable to tracer. Entry of tracer then can be used to indicate correctly the location or severity of flaws. The relative impermeability of intact dental enamel permits such testing of the enamel-restoration interface seal, but the same is not true when using dentine, which is usually frankly porous to most tracers through its tubules. False positive results are very likely. Recent intense interest in dentine bonding agents has increased the need and frequency of these tests with dentine, but this serious confounding factor has so far generally remained unstated, and has only been controlled adequately in one study. If tracer penetration test results are to be meaningful, then adequate control is required.

Animals↗
PubMed1994

Dentin permeability to bacterial proteins in vitro.

Passage of bacterial components through dentin is a subject of recent research with in vitro as well as with in vivo models. Diffusive transport of Porphyromonas gingivalis ATCC 33277 proteins has been demonstrated by the authors with an in vitro setup closely simulating the pulp chamber. The purpose of this investigation was to study the filtration of these proteins through dentin, measure possible concentration changes resulting from the filtering, and elaborate on the physical aspects of the binding process. The hydraulic conductance (Lp) of 10 dentin specimens was determined in three experiments using standard procedures: initially with phosphate-buffered saline, subsequently with a P. gingivalis ATCC 33277 suspension (200 micrograms/ml of protein), and finally with phosphate-buffered saline. The results showed significant, nonpermanent, alterations of the Lps of the dentin disks, and variable retention of the bacterial proteins among samples. A positive correlation between the bacterial protein retention and reduction of Lps was also demonstrated. The reduction of the Lps of the dentin samples was attributed to microstructural changes of the dentin, while the bacterial protein retention was considered to take place either on the surface of the disk or intratubularly. The intratubular interactions in the present experiment seemed to have a mechanical rather than a chemical basis.

Bacterial Proteins↗
PubMed2004

Comparative study of dentine permeability after apicectomy and surface treatment with 9.6 microm TEA CO2 and Er:YAG laser irradiation.

Failure of apicectomies is generally attributed to dentine surface permeability as well as to the lack of an adequate marginal sealing of the retrofilling material, which allows the percolation of microorganisms and their products from the root canal system to the periodontal region, thus compromising periapical healing. The purpose of this study was to evaluate dentine and the marginal permeability after apicectomy and surface treatment with 9.6 micro m TEA CO(2) or Er:YAG 2.94 micro m laser irradiation. Sixty-five single rooted human endodontically treated teeth were divided into five experimental groups: group I (control), apicectomy with high speed bur; group II, similar procedure to that of group I, followed by dentinal surface treatment with 9.6 micro m CO(2) laser; group III, similar procedure to group I followed by dentinal surface treatment with Er:YAG laser 2.94 micro m; group IV, apicectomy and surface treatment with CO(2) 9.6 micro m laser; and group V, apicectomy and surface treatment with Er:YAG laser 2.94 micro m. The analysis of methylene blue dye infiltration through the dentinal surface and the retrofilling material demonstrated that the samples from the groups that were irradiated with the lasers showed significantly lower infiltration indexes than the ones from the control group. These results were compatible with the structural morphological changes evidenced through SEM analysis. Samples from groups II and IV (9.6 micro m CO(2)) showed clean smooth surfaces, fusion, and recrystallized dentine distributed homogeneously throughout the irradiated area sealing the dentinal tubules. Samples from groups III and V (Er:YAG 2.94 micro m) also presented clean surfaces, without smear layer, but roughly compatible to the ablationed dentine and without evidence of dentinal tubules. Through the conditions of this study, the Er:YAG 2.94 micro m and the 9.6 micro m CO(2) laser used for root canal resection and dentine surface treatment showed a reduction of permeability to methylene blue dye.

Apicoectomy↗
PubMedDate not supplied

[Evaluation of pH variation and cervical dentin permeability in teeth submitted to bleaching treatment].

External cervical root resorption is one of the disadvantages of the bleaching procedure. There are several mechanisms that may be responsible for causing resorption, such as the chemical and physical action of the utilized materials and the morphology of the cementoenamel junction. The purpose of this study was to investigate the presence of a communication between the pulp chamber and the external root surface. The investigation was carried out by means of pH tests and measurement of dye infiltration into cervical dentin after the bleaching procedure. Thirty-four human permanent incisors were submitted to endodontic treatment. The teeth were assigned to three experimental groups, according to the level at which the filling was cut, and to the sealing of the root canal entrance with glass ionomer cement. Sodium perborate and 30% hydrogen peroxide were utilized for bleaching. pH readings were carried out after 30 minutes, 24 h, 48 h and 72 h from the beginning of the procedure. The teeth were immersed in 0.5% basic fuchsin for 24 h in order to determine possible differences in the permeability of cervical dentin. The results revealed that pH tended to change when the root filling was cut at the entrance of the canal, when 2 mm of the filling were removed, and when the canal entrance was sealed with glass ionomer. Dentinal permeability increased in the three experimental groups, in comparison with the control group. These slight differences may suggest a communication between the pulp chamber and the external root surface.

Dentin↗
PubMed2006

Reduction in dentin permeability using a slurry containing dicalcium phosphate and calcium hydroxide.

Treatments that obdurate dentin tubules have been used for reducing dentin hypersensitivity. The purpose of this study was to determine the effect of a treatment with a slurry of micron sized calcium phosphate on the hydraulic conductance (L(p)) of etched dentin discs in vitro. The treatment slurry was prepared by mixing a powder mixture of dicalcium phosphate anhydrous and calcium hydroxide with a solution that contained sodium fluoride and carboxymethyl cellulose. The mean baseline L(p) (in mL cm(-2) s(-1) H(2)O cm(-1)) was 2.07 +/- 1.45 (mean +/- SD; n = 13)). After one treatment and 2, 4, and 7 days of incubation in a protein-free saliva-like solution (SLS), the mean relative L(p), presented as % of baseline, were 65 +/- 16, 42 +/- 27, 36 +/- 26, and 33 +/- 27 (n = 13), respectively. The L(p) values of the baseline and treatment after incubation in the SLS were significantly (p < 0.05) different. Scanning electron microscopic examination showed partial obturation of dentin tubules in the treated dentin. X-ray diffraction and chemical analyses indicated the major product formed from the slurry was a fluoride-containing hydroxyapatite. Treatment appeared effective in further reducing L(p) of dentin discs after incubation in the SLS.

Calcium Hydroxide↗
PubMed1978

Dentin permeability: changes produced by iontophoresis.

Iontophoretic currents (0--1.0 mA) were applied to dentin disks prepared from human third molars. A negative electrode increased 125I-permeation 10X, while a positive electrode increased 14C-lidocaine 8X. Iontophoresis appears promising as a method to increase the permeation of dentin by ionized substances of therapeutic interest.

Carbon Radioisotopes↗
PubMed1983

Dentin permeability: effects of temperature on hydraulic conductance.

The rates of fluid movement across dentin discs, in vitro, were measured at 10, 20, 30, 40, and 50 degrees C in unetched and acid-etched dentin. Increasing the temperature 40 degrees (i.e., from 10 to 50 degrees C) resulted in a 1.8-fold increase in fluid flow in unetched dentin, which was of a magnitude similar to the decrease in viscosity that occurred over the same temperature range. In acid-etched dentin, the 40 degrees C temperature change produced more than a four-fold increase in fluid conductance, more than double that which could be accounted for by changes in viscosity. Analysis of the data suggests that this additional increment in hydraulic conductance is due to thermal expansion-induced increases in tubular diameter.

Acid Etching, Dental↗
PubMed1992

Effect of aging and caries on dentin permeability.

Extracted human teeth were collected from young (20-28 yrs) versus old (45-69 yrs) patients. The teeth were divided into carious and noncarious groups. Slabs were created from the mid-coronal occlusal dentin. Carious lesions were excavated and the smear layers on both normal and excavated carious dentin were removed with 37% phosphoric acid (1 min). The permeability (hydraulic conductance) of old normal dentin was only 20% of that obtained in young normal dentin but all of the specimens were permeable. Young carious dentin was only 14% as permeable as young normal dentin and only 1 out of 7 specimens was not permeable. All 7 specimens of old carious dentin were impermeable. Scanning electron microscopy of old and carious dentin exhibited far more intratubular crystals than normal dentin, providing a structural basis for the functional observation.

Adult↗
PubMed1981

Comparison of in vitro and in vivo dog dentin permeability.

A method is described which permits the quantitation of the rate of permeation of 131I through dog dentin, both in vivo and in vitro. The results demonstrate the rapidity of the systemic appearance of substances placed on intact dentin. Comparison of the rate of permeation of 131I made in vivo and in vitro, on the same teeth, indicates the rates are very similar.

Animals↗