Biomedical subjects

Z C Cehreli

Publications and source records attributed to Z C Cehreli.

17 recordsLinked to original sources

PubMed2006

Buccal and palatal talon cusps with pulp extensions on a supernumerary primary tooth.

This paper reports an unusual occurrence of talon cusp on a supernumerary primary incisor, presenting on both labial and palatal sides. The tooth was scheduled for extraction due to its interference with the occlusion. Morphometric analysis of the taloned cusps was performed on digitized replicas of the tooth crown using open-source image analysis toolkit (ImageJ). Further non-destructive investigation of the taloned crown under cone-beam X-ray computed tomography revealed pulpal extensions in both talon cusps.

Child, Preschool↗

PubMed2004

Effects of self-etching primers on vascular responses in rat carotid artery.

To investigate the effect of self-etching bonding systems on the control of pulpal haemorrhage in direct pulp exposures by observing the contraction of pulp blood vessels using the rat carotid artery model. Six dentine-bonding agents (Mac Bond, One-Up Bond F, Clearfil SE Bond, FL Bond, Prompt L-Pop and Prime and Bond NT) were used. The efficacy of bonding agents were compared with that of epinephrine for dose and the contraction forces (vasoconstriction) induced on the smooth muscle and the results recorded using a force displacement transducer. Dose-dependent relaxations caused by the test materials were recorded in the same manner in comparison with papaverine. FL Bond, SE Bond, One Up Bond, Mac Bond produced dose-dependent relaxations, while Prompt L-Pop and Prime&Bond NT produced epinephrine-like contractions on the rat carotid artery. For self-etching primers, which produce vascular relaxation, haemorrhage control with additional chemicals should be considered if direct pulp capping is to be performed using such adhesive systems.

Animals↗

PubMed2001

Effect of gutta-percha solvents at different temperatures on the calcium, phosphorus and magnesium levels of human root dentin.

The aim of this study in vitro investigation was to evaluate the alterations caused by warmed gutta-percha solvents on the calcium, phosphorus and magnesium levels of root dentin. Extracted human anterior teeth, whose crowns and apical root thirds had been removed were used as root dentin specimens. The roots were sectioned longitudinally into two segments, cleaned and dried. Segments were divided into 12 groups (n=12). In 6 groups, the specimens received treatment with the following solvents at room temperature (22 degrees C): Chloroform, xylene, eucalyptol, orange oil, halothane and saline (control). Within each group, the specimens were further subgrouped into two to be incubated (100% humidity at 37 degrees C) for 5 and 10 min, respectively, following treatment with the solvents. The remaining six groups were treated with the same solvents which had been previously warmed to body temperature (37 degrees C) and received the same experimental procedures. The levels of calcium, phosphorus and magnesium in each specimen were analysed using energy dispersive spectrometric microanalysis. Statistical analysis of the readings showed that neither warming of the solvents nor prolonged incubation (treatment) time was capable of altering the histochemical composition of cut root dentin surfaces.

Body Temperature↗

PubMed2001

Neurotoxic effects of fifth-generation dentin adhesives on rat sciatic nerve.

This study evaluated the effect of the fifth-generation dentin adhesives, Single Bond (SB), Excite (EX), Prime & Bond NT (PB), and Optibond Solo (OS) on nerve conduction. Isolated rat sciatic nerves were placed between two suction electrodes in a bath containing tyrode solution. The bonding agents were brought into contact with the nerves and the evoked compound action potentials (cAPs) were recorded before and after contact with the materials. SB, EX, and PB caused total inhibition of the cAPs, with PB being the fastest (73 +/- 5.8 min). All cAPs except one in the PB group were irreversibly inhibited in the SB, EX, and PB groups. As for OS the reduction in cAP was not 50% after an application time of 200 min. Recovery of the cAPs in this group was recorded in an average time of 35 min.

Action Potentials↗

PubMed2001

Antibacterial activity of fifth-generation dentin bonding systems.

Past concepts that the pulp does not become infected until an actual carious exposure takes place have been challenged. The antibacterial effects of the dentin bonding systems Single Bond, Prime&Bond NT, and Excite were evaluated using the bacteria Streptococcus mutans ATCC 25175, Streptococcus intermedius, Lactobacillus acidophilus, Prevotella oris, Prevotella bivia, Prevotella denticola, Porphyromonas gingivalis, Porphyromonas endodontalis, and Clostridium ramosum with a disk diffusion method. Chlorhexidine (0.2%) was used as a positive control. After incubation zones of inhibited bacterial growth were measured. Prime&Bond NT showed growth inhibition for all bacterial strains. Lactobacillus acidophilus and Streptococcus mutans were remarkably resistant to Single Bond, whereas EX produced no inhibitory effect on Porphyromonas endodontalis, although the adhesive produced the maximum halo inhibition to Streptococcus mutans (15+/-1 mm), showing an antibacterial effect closest to chlorhexidine. The variety of results obtained in this study suggest that antibacterial properties of current dentin adhesives may depend on components that are originally incorporated to promote adhesion.

Anti-Infective Agents, Local↗

PubMed2000

Three-year clinical evaluation of a polyacid-modified resin composite in minimally invasive occlusal cavities.

OBJECTIVE: The aim of this study was to evaluate the 3-year clinical performance of one polyacid-modified resin composite material (PMRC). Dyract, in minimally invasive occlusal cavities and its neighbouring fissures. METHODS: One hundred and sixteen restorations of the material investigated were placed by a single operator in a group of selected children under controlled conditions. Isolation of the restorations was accomplished with the use of cotton rolls and aspiration. Using modified US Public Health Service (USPHS) codes and criteria, the restorations were reviewed clinically within 1 week of placement (baseline), and thereafter at 6 months, 1, 2 and 3 years. RESULTS: After 3 years, marginal discolouration was present in 8.6% of the restorations. The marginal adaptation was rated as partly sealed (Oscar-Alpha) in 107 (92.2) of the restorations. Five restorations had lost their sealant components, while four restorations were partly sealed with explorer-catch after 3 years. Although wear of the restorations was considerable, restorations rated as 'partly sealed' had at least two-thirds of their sealant components fully retained. Recurrent caries was associated with four (3.4%) restorations. CONCLUSION: In this clinical study, the retention rate of the tested PMRC material was good, although a marked occlusal wear was evident. The marginal adaptation of the PMRC at the enamel site would probably have been better by the use of enamel-etching. Provided the marginal adaptation and wear resistance of the material is further improved, clinical use of PMRCs in minimally invasive occlusal cavities can be advocated.

Child↗

PubMed2000

Effects of a nonrinse conditioner and 17% ethylenediaminetetraacetic acid on the etch pattern of intact human permanent enamel.

The purpose of this study was to evaluate the effects of 2 new acid-etching solutions, nonrinse conditioner (NRC) and 17% ethylenediaminetetraacetic acid (EDTA), on enamel surface morphology, and to compare the new solutions with traditional 37% phosphoric acid. The effect of prolonged etching time was also investigated. The buccal surfaces of 80 extracted third molars were etched with one of the 3 acids for 15, 30, or 60 seconds. The central regions of the specimens were examined with a scanning electron microscope. Shorter etching time with phosphoric acid resulted in a relatively smooth enamel surface compared with longer treatments. Irrespective of treatment time, NRC produced an aprismatic etch pattern, which suggested a potentially retentive morphological character. EDTA treatment had the least effect of all etchants tested.

Acid Etching, Dental↗

PubMed2000

Effect of a fifth-generation bonding agent on vascular responses in rats.

In the last years, several single-bottle dental adhesives have been developed. They are supposed to chemically adhere to dentin, and a liner to protect pulp is not thought to be necessary. In the case of direct pulp capping, hemorrhage control is an important step in success, but little is known about the effect of these new bonding agents on pulpal bleeding. The aim of this study was to evaluate the effect of a new one-step single-bottle adhesive on the smooth muscle contraction of rat uterine muscle and carotid arteries. Efficacy of the bonding agent was compared with that of epinephrine (control), and the contraction forces induced were recorded using a force displacement transducer. Statistical analysis of data revealed that the bonding material produced epinephrine-like concentration-dependent contractions of the smooth muscle, suggesting that one-step bonding agents may act as candidates for hemorrhage control without the use of an additional agent in direct pulp capping procedures.

Analysis of Variance↗

PubMed2000

Surface tension of root canal irrigants.

The aim of this study was to evaluate the surface tension values of established and potential endodontic irrigants to which a surface active agent had not been added. Additionally, Cetredixine, a surfactant-containing 0.2% chlorhexidine gluconate solution, was included in the measurements. Surface tension measurements were performed using the ring method on a DuNouy tensiometer at a standard room temperature. Ringer's solution, saline solution, and distilled water had the highest surface tension values, whereas those of NaOCl (2.5% and 5%) and 17% EDTA were relatively low. Two anesthetic solutions, Ultracaine and Citanest, demonstrated values similar to NaOCl and EDTA, although a statistically significant difference was found between all solutions tested. Cetredixin displayed the lowest surface tension. A low surface tension agent should penetrate tubules better.

Analysis of Variance↗

PubMed2000

Short term human primary pulpal response after direct pulp capping with fourth-generation dentin adhesives.

The purpose of this study was to evaluate the effects of the total-etch and direct pulp capping techniques on the short-term response of mechanically exposed human primary tooth pulps using three commercially available adhesive resin systems. Class V cavities were prepared on the buccal surface of intact mandibular primary molars and exposed with a carbide bur on the cavity floor. The entire cavity except the exposure site received 36% phosphoric acid gel conditioning. Exposed pulps were capped with one of the three adhesive resins, followed by restoration of the cavities with the respective restorative materials. The teeth were extracted after 60 days and prepared according to normal histological techniques. Serial sections were stained with H/B for histological evaluations. The histopathological evaluation showed that a few of the samples in the Scotchbond Multi Purpose (SMP) and Prime & Bond 2.1 (PB) groups exhibited "attempted bridge formation", while no bridge formation was evident in the other samples. Syntac Single Component (Syntac) exhibited the most severe histological response, while the mildest reactions were observed in the SMIP group. Based on the conditions of the present study, direct pulp capping with dentin bonding agents following the total-etch technique in primary teeth can not be recommended.

Acid Etching, Dental↗

PubMed2000

Effect of different single-bottle dentin adhesives on vascular responses in rat carotid artery.

PURPOSE: To investigate the effect of one-bottle dentin bonding systems on pulpal hemorrhage control in direct pulp exposures through contraction of pulp blood vessels using the rat carotid artery model. MATERIALS AND METHODS: Four dentin bonding agents (Prime & Bond 2.1, Prime & Bond NT, Syntac Single Component and Single Bond) were used. The efficacy of bonding agents were compared to that of epinephrine (control) in the viewpoint of the concentration applied and the contraction forces induced on the smooth muscle were recorded using a force displacement transducer. RESULTS: Three of the test materials produced epinephrine-like contractions on the rat carotid artery (smooth muscle) while no reading could be achieved with Single Bond. A ranking between the bonding agents for contraction forces was obtained as follows: Prime & Bond NT > Prime & Bond 2.1 > Syntac Single Component (P < 0.05).

Analysis of Variance↗

PubMed2000

Etching effect of 17% EDTA and a non-rinse conditioner (NRC) on primary enamel and dentin.

PURPOSE: To investigate the effect of a new non-rinse conditioner (NRC) and 17% EDTA as etchants on the micromorphology of primary tooth enamel and dentin, in comparison with 36% phosphoric acid (PA) when applied for 15 s and 7 s. MATERIALS AND METHODS: Enamel specimens obtained from 40 extracted primary second molars were used to create four groups (n=10) which received the following treatments on unground enamel surface: Group 1: 36% PA/15 s, Group 2: 36% PA/7 s, Group 3: NRC 20 s, Group 4: 17% EDTA/60 s. The same treatments were applied on flattened primary tooth dentin specimens (four groups/n=10). All treated surfaces were examined by SEM. RESULTS: For enamel specimens, a Type II etching pattern was evident in Groups 1 and 3. In Group 2, an uneven Type II pattern was present with prism peripheries partially intact. A mixture of Type II and Type III etching patterns were observed in Group 4. Although all conditioners removed dentin smear to varying degrees, the overall performance of 17% EDTA was weaker than PA and NRC.

Acid Etching, Dental↗

PubMed1999

Comparison of shear bond strength of three bonding agents with metal and ceramic brackets.

Shear bond strengths of a light-cured composite resin, a light-cured glass ionomer cement, and a light-cured compomer used with metal and ceramic brackets were compared, and ARI scores were evaluated. Ceramic brackets showed statistically higher shear bond strengths than metal brackets when bonded with all test materials (p<0.001). When used with metal brackets, the light-cured glass ionomer cement (LCGIC) and compomer materials demonstrated statistically lower shear bond strengths than the light-cured composite (p<0.01 and p<0.001, respectively). When used with ceramic brackets, LCGIC was found to have significantly lower shear bond strength than the composite material (p<0.001). Despite its relatively low shear bond strength, LCGIC demonstrated optimal bonding values (8.39+/-3.24 MPa) with ceramic brackets. Bond failures within the LCGIC groups occurred at the adhesive-tooth interface, whereas in the compomer and composite groups, failures were detected at the adhesive-bracket interface. In the metal bracket group, clinically acceptable shear bond strength was obtained only with the composite resin (7.06+/-1.65 MPa). Compomer and LCGIC demonstrated values well below the accepted standard for metal brackets (4.32+/-1.75 MPa and 4.45+/-1.06, respectively), while in the ceramic bracket group, values for composite and compomer were above the desired level (14.40+/-5.88 MPa and 12.31+/-6.09, respectively). LCGIC showed reasonably good bond strength with ceramic brackets, suggesting that this material may be considered suitable for use with ceramic brackets in clinical situations where moisture cannot be controlled.

Acrylic Resins↗

PubMed1999

Effect of surface conditioning on the shear bond strength of compomers to human primary and permanent enamel.

PURPOSE: To compare the bond strength of two polyacid-modified composite resins (Compomer) to primary and permanent enamel with and without acid-etching and to test for a possible relationship between the determined shear strength values and area of cohesive failure within the materials on the bonding interface. MATERIALS AND METHODS: Two compomer materials (Dyract and Compoglass) with their respective one-bottle primer/adhesive agents (Prime & Bond 2.0 and Syntac Single Component) were investigated. The parameters tested were shear strength and area of cohesive type of failure after debonding of specimens with respect to the total area of the bonding interface. RESULTS: Mean bond strength to primary enamel ranged from 4.09 MPa (Compoglass) to 5.6 MPa (Dyract), while in permanent enamel the mean values were between 12.3 MPa (Compoglass) and 14.3 MPa (Dyract), when pretreatment was made with bonding agents only. Generally, acid-etching prior to pretreatment improved adhesion significantly (6.0 MPa and 8.1 MPa in primary enamel and 16.0 MPa and 19.4 MPa in permanent enamel for Compoglass and Dyract, respectively). Over one-half of the variation in the values for cohesive failure area was explained by its linear relationship with shear bond strength.

Acid Etching, Dental↗

PubMed1996

Dentinogenesis imperfecta: influence of an overdenture on gingival tissues and tooth mobility.

Case report of a child demonstrating severely-worn primary dentition with dentinogenesis imperfecta is presented. Overdentures were fabricated in order to preserve clinical crowns, re-establish the clinical dimension of occlusion and provide esthetics. The patient underwent monthly recall visits for a 6-month period, during which most rapid changes concerning the gingival tissues and tooth mobility were expected.

Alveolar Bone Loss↗

PubMed1996

The use of a special mouthguard in the management of oral injury self-inflicted by a 4-year-old child.

This paper describes the management of self-inflicted trauma by a 4-year-old boy who was mentally retarded as a result of encephalitis in infancy. There was severe damage to his lower lip, as well as a moderate degree of injury to the skin and nail of his right thumb. Preliminary intervention was made with a mouthguard using silicone elastomeric positioner material, which soon proved ineffective because of poor retention. The problem was overcome successfully through use of a special appliance in which a heat-cured acrylic base was combined with a superstructure made of silicone positioner material retained mechanically with retention loops of 0.7 mm orthodontic wire.

Acrylic Resins↗

PubMedDate not supplied

Effect of 1.23 percent APF gel on fluoride-releasing restorative materials.

This study evaluated the effect of a 1.23 percent APF gel on the surface morphological characteristics and surface roughness of one high-viscosity (Fuji IX GP), three polyacid-modified resin-based composites (Dyract AP, F2000 and Compoglass F) (PMRC), and two resin-modified glass-ionomer cements (Vitremer and Fuji II LC). A microfilled nonfluoridated resin-based composite (Silux Plus) was used as a control. All materials were handled according to the manufacturers' instructions. The fluoride gel used in the study was a 1.23 percent acidulated phosphate fluoride gel (APF) (Nupro APF). The specimens were repeatedly exposed to the APF gel with cotton applicators for a period that simulated the equivalent of 4 yrs (1 min/6 mo) under prophylactic fluoride treatment. Average surface roughness (Ra) of the control and treated specimens was measured. Three separate Ra measurements along the direction of rotation of the finishing and perpendicular to the finishing direction and edge of the mold were made for each specimen surface. In each group, specimens with Ra closest to the mean were removed from the molds, sputter-coated with gold and examined using a scanning electron microscope. The results showed that all tested materials, except Vitremer, displayed increased surface roughness values following APF treatment. However, this was not statistically significant for Compoglass F, Vitremer and Fuji II LC. Among PMRC materials, F2000 displayed the highest Ra average value, although the differences between F2000 and Dyract AP and of Compoglass F and Dyract AP was not statistically significant. Comparisons of the Ra values between Silux Plus and the other test materials revealed statistically significant differences except for Dyract AP and Compoglass F. No statistically significant difference was found between the Ra values of Vitremer and Fuji II LC following APF treatment. Among all groups, Fuji IX GP displayed the highest surface roughness.

Acidulated Phosphate Fluoride↗