Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Tooth 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 739 records · Page 41Linked to original sources
PubMed1992

Subsurface demineralization in dental enamel and other permeable solids during acid dissolution.

Subsurface demineralization of dental enamel during acid dissolution has been reported many times, but its cause remains obscure. At first, the phenomenon was thought to result from the physical structure of enamel. More recent studies have shown that subsurface demineralization occurs in other permeable solids, indicating that there must be more fundamental factors involved in this curious effect. In order for this phenomenon to be investigated, dissolution experiments were carried out by means of real-time scanning microradiography in various systems, including enamel, or aggregates of hydroxyapatite (calcium, strontium, or barium), or hydroxides (calcium or magnesium). These were chosen to discriminate between effects of structure and composition. It was found that it was not possible for the demineralization observed in these systems to be attributed to a common feature. From this, it is concluded that subsurface demineralization in enamel and other mineralized tissues should not be ascribed to a single cause.

Acetates↗
PubMed2003

Penetrating the plaque biofilm: impact of essential oil mouthwash.

The interaction between saliva-coated tooth surfaces and pathogenic bacteria is partly governed by electrostatic and hydrophobic interactions, providing a solid rationale for using chemical agents as part of a plaque-control routine. Chlorhexidine works in several ways. For example, it binds to salivary mucins on the bacterial cell membrane, and penetrates the plaque biofilm. Essential oil (EO) mouthwashes kill micro-organisms by disrupting their cell walls and inhibiting their enzymic activity. They prevent bacterial aggregation, slow multiplication and extract endotoxins. Recent studies have shown that bacterial phenotypes are altered when organisms change from a planktonic to a sessile state. This suggests that an effective mouthwash must also penetrate the plaque biofilm. Two studies have demonstrated the ability of an EO mouthwash to penetrate the plaque biofilm.

Anti-Infective Agents, Local↗
PubMed1991

Pulp therapy in the primary dentition.

Several treatment options for pulp therapy in primary teeth are reviewed. Conservative treatments are recommended for primary teeth whose pulps have the potential to recover once the irritation has been removed. The role of dentin permeability and microleakage is emphasized when protective basis and indirect pulp treatment are discussed. Alternative dressings for formocresol pulpotomies such as 6.25% glutaraldehyde solution, antigen-extracted allogeneic dentin matrix, and crude bone morphogenetic protein are reported with promising results. Pulpectomy is recommended for teeth with evidence of chronic inflammation involving radicular pulp or pulp necrosis with and without periapical involvement. The main disadvantage of zinc oxide-eugenol paste, widely used for primary root fillings in the United States, is its slow resorption rate, frequently much slower than that of the root. Other root canal pastes containing iodoform, or a modification of this with the addition of calcium hydroxide, are being utilized in South America, Japan, and Europe.

Child, Preschool↗
PubMed1997

Fluoride profiles in the cementum and root dentine of human permanent anterior teeth extracted from adult residents in a naturally fluoridated and a non-fluoridated area.

OBJECTIVES: To determine the effect of water fluoride concentration on the fluoride profile across the entire thickness of the cementum and root dentine of human permanent anterior teeth in adults. SUBJECTS: Twenty-eight human permanent anterior teeth from individuals aged from 30 to over 60 years were studied. SETTING: Teeth were obtained from a natural high-fluoride area (West Hartle-pool, UK; 1.0-1.3 ppm F in drinking water, WHP) and the other from a non-fluoridated naturally low fluoride area (Leeds, UK; 0.1 ppm F in drinking water, LDS). DESIGN: Cementum and root dentine were sampled using an abrasive micro-sampling technique from the cementum surface to the pulpal surface of root dentine. RESULTS: Fluoride concentration was higher in tooth roots (the cementum and dentine) taken from the naturally fluoridated area (WHP) than from the non-fluoridated area (LDS). Age and average fluoride concentration showed a positive correlation in WHP dentine, middle region of the root (r = 0.78, P < 0.001) and in the apical region of the root (r = 0.61, P < 0.05). WHP cementum had the strongest fluoride concentration correlation with age in the cervical region of the root (r = 0.67, P < 0.01). An analysis of variance (ANOVA) showed that the area (water fluoride content), age and number of years lived in the area combined with total age were significant. CONCLUSIONS: The fluoride content of cementum and root dentine in adult residents is related to fluoride content in drinking water.

Adult↗
PubMed2003

A morphological and micro-tensile bond strength evaluation of a single-bottle adhesive to caries-affected human dentine after four different caries removal techniques.

OBJECTIVES: This study evaluated the influence of different caries removal techniques (conventional bur; chemomechanical removal/Carisolv()-MediTeam; a sonic preparation system/SonicsysMicro-Kavo and air abrasion/PrepStar-Danville Engineering) on microtensile bond strength to caries-affected human dentine. METHODS: Occlusal surfaces of extracted human permanent third molars with coronal dentine caries extending approximately halfway through the dentine was ground perpendicular to the long axis of the tooth to expose a flat surface of normal dentine surrounding the carious lesion with laser fluorescence values of approximately 30 (DIAGNODent), KaVo). Carious lesions were excavated with one of the four techniques until laser fluorescence values decreased to 15 in the center of the lesions. An ethanol-based dentine adhesive (Single Bond, 3M) was used to bond composite resin (P60, 3M) to the substrate. Vertical slices (n=11/group), approximately 0.8 mm thick were made through the caries-affected portions of each tooth, perpendicular to the bonding surface. Specimens were subjected to tensile stress at a crosshead speed of 1 mm/min. Data were analyzed by Kruskal-Wallis test. SEM investigation was performed for the qualitative evaluation of resin-dentine hybridization. RESULTS: The microtensile bond strengths were as follows (mean+/-SD in MPa): 6.4+/-5.3 (bur), 8.4+/-3.3 (Carisolv), 8.5+/-5.9 (Sonicsys Micro), and 8.8+/-8.8 (air abrasion). Statistical analysis did not show significant differences between any of the treatment modalities (p=0.160). Tensile fracture was cohesive within caries-affected dentine in all specimens. CONCLUSIONS: The four different caries removal techniques used within this study did not influence the bond strength of the tested dentine adhesive to caries-affected human dentine.

Air Abrasion, Dental↗
PubMed2006

The role of acrylophosphonic acid monomers in the formation of hybrid layers based on self-etch adhesives.

UNLABELLED: The role of acrylophosphonic acid monomers in the formation of hybrid layers based on self-etch adhesives. OBJECTIVES: Our plan was to define the reaction products formed when an acrylophosphonic acid reacts with tooth hard tissue. Our aim was to describe the incorporation of the reaction products in the hybrid layer formed. METHODS: Potentiometric methods were used to measure acid dissociation constants and investigate calcium complex formation. Infrared spectroscopy and NMR were used to follow water contents and show transformation of phosphorous containing compounds. RESULTS: The acrylophosphonic acid contained in AdheSE (Ivoclar Vivadent, Schaan, Liechtenstein) is characterized by two acidities with pK(a1)=2.4 and pK(a2)=7.0, and interacts with calcium ions in a purely ionic fashion. When hydroxyapatite crystals are dissociated by the presence of AdheSE, brushite is formed together with a calcium cross-linked network of the phosphonate containing copolymer. CONCLUSION: The results give a new image of the hybrid layer where the adhesive behaves like an ionomer resin incorporating collagen but also minerals and salt bridges.

Acid Etching, Dental↗
PubMed2001

Association between microtensile bond strength and leakage in the indirect resin composite/dentin adhesively bonded joint.

PURPOSE: Develop a methodology to correlate microtensile bond strength (microTBS) and leakage within the same site of a specimen and evaluate the predominate debond and leakage pathways. MATERIALS AND METHODS: A Class II (MO) slot cavity was prepared in 37 extracted human molars and restored with indirect resin composite restorations. The restored teeth were thermocycled 300X between 5 and 55 degrees C and then stained with silver. Two specimens per tooth were obtained by diamond saw sectioning for measurement of leakage (microm) and microtensile bond strength (MPa) at the gingival wall and then tested for association with regression analysis. Scanning electron microscopy techniques and energy dispersive spectroscopy (EDS) were used to evaluate the debond and leakage pathways. RESULTS: Association between leakage and bond strength was not significant (t=1.31, p=0.198). All 74 samples debonded within the joint, predominantly at the hybrid layer-adhesive resin region with only one specimen including a small portion of resin cement in the debond pathway. Secondary and backscatter imaging and EDS analysis showed leakage in all samples that involved the hybrid layer. CONCLUSION: This study demonstrates a feasible method for evaluating leakage and bond strength at the joint interface within the same specimen.

Composite Resins↗
PubMed1986

Tooth surface-pellicle lipids and their role in the protection of dental enamel against lactic-acid diffusion in man.

The lipid content and composition of the enamel pellicle from caries-resistant (CR) and caries-susceptible (CS) subjects and their effect on its ability to retard the diffusion of lactic acid were investigated. Lipids accounted for 22.2 per cent of the dry weight of CR pellicle and 23.7 per cent of CS pellicle. The content of glycolipids in both groups was similar but CR pellicle contained 42 per cent less neutral lipids and 31 per cent less phospholipids. CR lipids had a higher content of cholesterol, cholesterol esters and sphingomyelin, whereas CS pellicle was richer in free fatty acids and phosphatidylethanolamine. Retardation of lactic-acid diffusion by CR pellicle was 45 per cent higher than by CS. Removal of lipids caused 50 per cent reduction in retardation by CR pellicle and 35 per cent by CS pellicle.

Adult↗
PubMedDate not supplied

Microleakage and penetration ability of resin sealant versus bonding system when applied following contamination.

PURPOSE: The purpose of this study was to evaluate the microleakage and penetration ability of sealing materials applied under different conditions of contamination. METHODS: One hundred twenty extracted human molar teeth were randomly assigned to 12 groups. The treatment groups were defined by the combination of sealing materials (Concise; Optibond system; Optibond system plus Concise) and 4 surface conditions (no moisture and no saliva contamination; moisture contamination; dried saliva contamination; wet saliva contamination). Each tooth was subjected to thermal cycling (5,000 cycles at 5 degrees C-55 degrees C) with a dwell time of 30 seconds and dye immersion (5% methylene blue for 24 hours). Microleakage, penetration ability, and fissure types were examined after sectioning. Multiple regression analyses and the Tukey test were used for statistical analysis. RESULTS: Concise showed significantly less microleakage than the Optibond system (P<.031) when the procedures were performed under no contamination or moisture contamination. However, when Concise was applied on the wet saliva-contaminated surfaces, considerably higher microleakage and unfilled areas were found compared to the use of Optibond alone or Optibond with Concise (P<.001). CONCLUSIONS: When there is saliva contamination, the use of Optibond alone or with Concise is beneficial for decreasing microleakage and increasing the penetration ability of sealants.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1997

Structure and function of secretory ameloblasts in enamel formation.

Secretory ameloblasts have multiple functions including the synthesis and resorption of enamel matrix proteins and calcium transport during enamel formation. We have examined these functions by means of cytochemistry and immunocytochemistry. Enamel proteins, amelogenins and enamelins are localized in the biosynthetic pathways of ameloblasts and in the forming enamel. Sulfated glycoconjugates are present in secretory ameloblasts. The distal junctional complex of ameloblasts may act as a permeability barrier to enamel proteins, thereby confining the secreted proteins to the growing enamel front. Secretory ameloblasts contain lysosomal enzymes in the Golgi lysosome endoplasmic reticulum system and also exhibit absorptive capacity, which might be associated with an early decrease in extracellularly degraded enamel proteins. Active calcium transport through the ameloblasts towards the growing enamel is indicated by the demonstration of Ca-ATPase activity along the plasma membranes. A calcium-dependent modulator protein, calmodulin, is localized in ameloblasts, suggesting that early enamel mineralization is dependent upon calmodulin-regulated Ca-ATPase in ameloblasts. These results suggest that the secretory ameloblast is a highly specialized multifunctional cell in the production, resorption and degradation of enamel matrix and in the active calcium transport essential for matrix mineralization during enamel formation.

Ameloblasts↗
PubMed2002

Calcium phosphate precipitation method for the treatment of dentin hypersensitivity.

PURPOSE: To evaluate the feasibility of the calcium phosphate precipitation (CPP) method as a treatment for dentin hypersensitivity using vital teeth of beagle dogs. Also, gingival tissue response to two types of CPP methods was examined histologically. MATERIALS AND METHODS: Dentin tubules of the dogs' vital teeth were exposed by shallow cavity preparation followed by etching with 50% citric acid to simulate the condition of hypersensitive dentin. After CPP treatment was applied to the vital tooth, the dentin surface and longitudinal sections were observed by SEM to evaluate the occluding ability of the CPP method. The precipitate was also analyzed by energy-dispersive X-ray microanalysis to obtain compositional information. The gingival tissue before and after CPP method was examined histologically with light microscopy. RESULTS: Dentin tubules were occluded homogeneously and completely with an apatitic mineral after application of the CPP treatment in vital teeth. However, the depth of the precipitate in dentin tubules from the dentin surface was approximately half that seen in extracted teeth. No histological change was observed in gingival tissues when NaHCO3 was used as a post-treatment solution of the CPP method, whereas another CPP method using NaOH solution resulted in atrophy and degeneration of the epithelium of gingival tissue.

Analysis of Variance↗
PubMed2002

Morphological and chemical characterization of the dentin/resin cement interface produced with a self-etching primer.

PURPOSE: The purpose of this study was to analyze a resin cement/dentin interface by comparing the diffusion of a resin cement into dentin surfaces pretreated with a self-etching primer with or without pretreatment by conventional acid etching. MATERIALS AND METHODS: Dentin surfaces of 8 unerupted human third molars were treated with a self-etch primer (Panavia 21) with or without conventional phosphoric acid pretreatment. Panavia 21 resin cement was applied according to manufacturer's instructions. Dentin/resin cement interface sections from each tooth were examined with scanning electron microscopy and micro-Raman spectroscopy. RESULTS: When the self-etch primer was used following conventional acid pretreatment, the resin cement did not penetrate to the depth of the zone of demineralized dentin, leaving a substantial area of exposed dentin matrix at the dentin/cement interface. In contrast, there was substantial resin cement diffusion throughout the demineralized dentin when the self-etch primer was used without acid etching pretreatment. CONCLUSION: The in vitro evaluation of resin cement penetration throughout the zone of demineralized dentin is an important step in identifying sites of exposed dentin matrix that may promote postoperative sensitivity and may leave the dentin/resin cement interface vulnerable to premature degradation under clinical conditions. In this study, the self-etch primer used alone produced substantial resin cement penetration and left no exposed dentin matrix at the dentin/resin cement interface.

Acid Etching, Dental↗
PubMed1994

An investigation into the pressure transmitted to the pulp chamber on crown cementation: a laboratory study.

Pressure changes in the pulp chamber resulting from crown cementation have not been previously quantified. An experiment was designed to investigate the effect of smear layer removal on the peak pressure transmitted to the pulp chamber with crown cementation. Ten matched pairs of single-rooted premolar teeth were collected from adolescents and prepared for full-coverage crowns. The pulp tissue from each tooth was removed. One tooth from each pair had the smear layer removed with the application of 37% phosphoric acid for 30 s. The null hypothesis states that the removal of the dentinal smear layer will not change pressure in the pulp chamber resulting from the cementation. Before cementation, a hydrostatic head of pressure was used to perfuse the tooth, and the perfusion rate was recorded. Crowns were cemented with zinc phosphate cement with a seating force of 100 N. The mean peak pressures recorded were 85 Pa (SE 12 Pa) with the smear layer intact, and 194 Pa (SE 49 Pa) when the dentin was etched. The difference in the peak pressures transmitted to the pulp chamber with the two groups was significant (p < or = 0.05). A significant negative correlation was found between dentin thickness and the peak pressure transmitted to the pulp chamber (r = -0.5531, p < or = 0.01). We have shown that the pressure transmission to the pulp chamber during crown cementation can be measured. Since smear layer removal significantly influences the peak pressure, it is concluded that the pressure detected is at least partially dependent on the fluid flow through the dentin.

Acid Etching, Dental↗
PubMed1996

Diffusion of calcium through dentin.

The purpose of this research was to investigate whether calcium ions from a paste of calcium hydroxide [Ca(OH)2] and saline introduced into root canals diffuse through the dentin to reach the surface of the root. Six teeth were opened and submitted to a biomechanical process, after which all the smear layer was removed. The experiment was divided into three phases: dissolution, dissolution and diffusion I, and dissolution and diffusion II. Dissolution-each tooth, with no Ca(OH)2 paste in place, was sealed both cervically and apically and stored in 700 ml of deonized water until calcium losses from the tooth into the water were stabilized. Dissolution and diffusion I-each root canal was filled with a paste of Ca(OH)2 and saline, sealed again apically and cervically, and returned to its solution. Dissolution and diffusion II-samples were divided into three parts: the control group or group 1, containing the original paste; group 2, in which the existing paste was diluted and the teeth were resealed and replaced in their solutions; and group 3, in which the existing paste was removed and a fresh paste was introduced. The diffusion was greater in group 3, followed by group 2. In the control group, we found a diffusion of calcium, which is statistically null. The results showed that calcium diffusion was observed, in the first 16 days, in all situations in which there was Ca(OH)2 paste inside the root canals.

Calcium↗
PubMed1987

Testing sealing properties of restorative materials against moist dentin.

The objectives of this investigation were (1) to develop a sensitive laboratory system that simulates the physiological and clinical conditions of a prepared human tooth in order to facilitate the determination of the bonding and sealing efficacies of restorative dental materials and (2) to conduct experiments with two dentin bonding agents, two posterior composite resin restorative materials (hybrid and microfilled), and a glass-ionomer type II filling material. The system functioned well and provided data to indicate that, after margination, the two posterior composite resin restorative materials performed equally and both performed better than the glass-ionomer filling material; none of the materials provided a perfect seal immediately after insertion, although some restorations demonstrated perfect seals from 16 hours to 28 days after placement; the seal of the glass-ionomer material improved after 28 days of storage in buffer solution; each successive step in the respective composite resin procedures improved the seal except in one case for the microfilled resin.

Composite Resins↗
PubMed1994

Morphologic aspects of the resin-dentin interdiffusion zone with five different dentin adhesive systems tested in vivo.

The new generation of enamel dentin adhesive materials provides removal of the smear layer, inducing structural changes in the dentinal surface and creating a retentive interdiffusion zone or hybrid layer between the two substrates. Some studies have demonstrated hybrid layer formation in in vitro samples, but few articles have described it in in vivo specimens. The hybrid layer forms in peritubular and intertubular treated dentin and improves adhesion between tooth surface and adhesive resins. This in vivo study investigated the formation of a hybrid layer by use of five different enamel dentin adhesive systems. The dentin adhesives systems were tested on flat dentin preparations made on vestibular surfaces of periodontally compromised teeth. The sample teeth were extracted immediately after the resin was cured. Half of the samples were used to visualize the hybrid layer and the other half to observe the morphology of the resin tags by use of scanning electron microscopy. All the tested products formed a hybrid layer. In many areas of samples of Gluma 2000, Scotchbond Multipurpose, All Bond 2, and Super Bond D Liner systems, characteristic reverse cone-shaped tags were visible. Resin tags produced by Clearfil Liner Bond adhesive were narrower at the apertures of tubules than those of the other four adhesive materials. Morphology of the hybrid layer and of the resin tags of these samples were similar to in vitro samples observed in other studies.

Composite Resins↗
PubMed2001

Regional bond strengths of adhesive resins to pulp chamber dentin.

Microleakage of oral microorganisms, which can occur due to the lack of sealing ability of permanent restorative materials, may cause failure of root canal treatments. Although a great deal of research has been done on sealing enamel and coronal dentin with resins, little research has been done on the adhesion of resins to the walls of pulp chambers. The purpose of this study was to evaluate regional bond strengths of two adhesive systems to the walls of pulp chambers. A section was made horizontally through the middle of the pulp chamber of extracted human third molars to divide the chamber into upper and lower halves. The pulp tissue was removed and the tooth segments were then divided into treatment subgroups. The pulp chambers were bonded with C&B Metabond (Parkell) or One-Step (Bisco), with or without 5% NaOCI pretreatment. The microtensile bond strengths of these resins to four different pulp chamber regions (bottom, wall, roof, and pulp horn areas) were then measured using an Instron machine. The data were expressed in MPa and were analyzed by a three-way ANOVA. Statistically significant differences were found among the test groups (p < 0.001). One-Step produced higher bond strengths to all pulp chamber regions except the floor, compared with C&B Metabond. The results indicated that high bond strengths can be achieved between adhesive resins and the various regions of the pulp chamber. This should permit the use of a thick layer of unfilled resin along the floor of the pulp chamber and over the canal orifices as a secondary protective seal after finishing root canal therapy.

Adhesiveness↗
PubMed2003

Ca2+ diffusion through dentin of Ca(OH)2 associated with seven different vehicles.

This investigation measured the diffusion of Ca2+ through dentin by using Ca(OH)2 associated with various vehicles. After mechanical preparation and removal of smear layer, 41 human premolar teeth were stored individually in flasks containing 800 ml of ultra-pure deionized water for 2855 h. The Ca2+ concentration was measured by atomic absorption spectrophotometry as a function of time. These measurements were divided into two phases: dissolution, to check the loss of Ca2+ from the tooth structure itself, for which all canals were kept empty and open in the absence of medication for 1168 h, and diffusion, in which the specimens were divided into 10 groups (3 control groups: group 1 = water control, group 2 = sealing control, and group 3 = open canal dissolution control; 7 experimental groups in which the whose canals were filled with Ca(OH)2 paste associated with the following vehicles: group 4 = saline; group 5 = polyethylene glycol (Calen); group 6 = glycerin and camphorated parachlorophenol group 7 = camphorated paramonochlorophenol; group 8 = glycerin; group 9 = glycerin and tricresol formaldehyde (TCF); and group 10 = anesthetic solution. This phase lasted 1687 h. A total of 1058 measurements of Ca2+ were made. Regression analysis was used for statistical evaluation. We concluded that diffusion occurred differently for each group: the medications used in the root canals interacted with the dentinal structure or among themselves; the medication coated the dentinal tubule, facilitating the diffusion of Ca2+ into the external part of the root.

Anesthetics, Local↗