Biomedical subjects

A Stabholz

Publications and source records attributed to A Stabholz.

At least 37 records · Page 2Linked to original sources

PubMed1997

Effect of XeCl-308nm excimer laser on the mineral content of human dentin.

The effect of the XeCl-308nm excimer laser on the mineral content and surface morphology of cut dentin was examined in ten extracted human teeth. Each dentin specimen was lased for 4 s at a fluence of 1 J/cm2 and a frequency of 25 Hz. Non-lased area of the same specimen served as control. Scanning electron microscopy and energy dispersive spectrometry revealed a significant decrease in the phosphorus levels following laser treatment. A decrease in calcium levels also occurred but was not statistically significant. Nonsignificant changes in sulphur and potassium levels were also noted. Morphologically, the lased dentin showed an apparently melted surface with partial obstruction of the dentin tubules as well as cracks along the lased surface. Therefore, it appeared that laser treatment may alter the chemical structure as well as the surface morphology of the dentin.

Calcium↗

PubMed1997

Sustained local delivery of chlorhexidine in the treatment of periodontitis: a multi-center study.

The safety and efficacy of a degradable, subgingivally placed drug delivery system containing 2.5 mg chlorhexidine (CHX) were evaluated in a randomized, blinded, multi-center study of 118 patients with moderate periodontitis. A split-mouth design was used to compare the treatment outcomes of scaling and root planing (SRP) alone with the combined use of SRP and the CHX in pockets with probing depths of 5 to 8 mm. The two maxillary quadrants were used for the two treatment arms of the study. Scaling and root planing was performed at baseline only, while the CHX was inserted both at baseline and at 3 months. Clinical and safety measurements including probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) as well as gingivitis, plaque, and staining indices were recorded at baseline, and at 1, 3, and 6 months. The average PD reduction in the CHX-treated sites was significantly greater than in the sites receiving SRP alone at both 3 and 6 months with a mean difference of 0.42 mm (P < or = 0.01) at 6 months. The reduction in CAL at the treated sites was greater than at the SRP sites, although the difference was statistically significant at the 6-month visit only. An analysis of patients with initial probing depths of 7 to 8 mm (n = 56) revealed a significantly greater reduction in PD and CAL in those pockets treated with CHX compared to SRP at both 3 and 6 months. The mean differences between test and control sites at 6 months were 0.71 mm and 0.56 mm PD and CAL respectively.

Adult↗

PubMed1997

The reasons for tooth loss in geriatric patients attending two surgical clinics in Jerusalem, Israel.

OBJECTIVES: Numerous studies around the world have been conducted in order to understand the reasons for tooth extractions in various age groups. Most studies have dealt with the general adult population but little attention has been paid to the elderly population. In Israel, as in most of the western countries, the elderly population is growing rapidly and thus demands for its dental needs are also increasing. In order to meet the dental requirements of the geriatric population, data on the main reasons of tooth mortality have been collected. DESIGN: Retrospective analysis of reasons for extraction divided into three categories: caries, periodontal disease and "other". SUBJECTS: The files of 302 consecutive elderly patients aged 65-95 years attending for extraction. The cause for tooth extraction was gathered from the written diagnosis described by the operator as well as from radiographs. Setting Two surgical clinics in Jerusalem serving low income residents. Results Results indicated that 30% of the extractions were due to caries, 65% were due to periodontal disease and only 6.4% related to "other" reasons. In both, males and females, periodontal disease was the major cause for tooth loss yet, females exhibited more extractions due to caries than males (35% vs 23% respectively). A relatively high incidence of tooth loss was documented for the 85+ age group. Of the teeth that were extracted, incisors and molars were equally the most frequent (29%) followed by premolars (26%) and canines (17%). Premolars were the teeth most frequently extracted out of the teeth removed due to caries (32%) whereas incisors were the most frequently removed within the group of teeth extracted due to periodontal disease (31%). CONCLUSIONS: The results of this study point to the importance of prevention and treatment of dental diseases, particularly periodontal disease, in adults aged 0 years and above in order to prevent tooth loss in their later years.

Aged↗

PubMed1996

Histochemical analysis of dental hard tissues following bleaching.

The effect of commonly used bleaching materials on the dental hard tissues was tested in extracted human premolars. In each tooth, the apical two-thirds of the root was removed, and the remaining tooth stump was cut longitudinally into two equal segments. The segments were cleaned, dried, and divided into six experimental groups. Each group was treated with one of the following bleaching materials: 30% hydrogen peroxide (HP), 10% carbamide peroxide (CP), sodium perborate (SP), Nu-Smile (NS), Opalescence (Op), and DentlBright (DB). Treatment consisted of immersing the specimens in the respective test material followed by incubation at 37 degrees C for 7 days. The levels of calcium, phosphorus, sulfur, and potassium were measured in the enamel, dentin, and cementum. In the enamel, a significant reduction in the calcium/phosphorus (Ca/P) ratio was found following treatment with HP. In the dentin, a significant reduction in Ca/P ratio was found following treatment with HP,CP, DB, and Op. In the cementum, a significant reduction in the Ca/P ratio was found following treatment with HP, CP, NS, and Op. Changes in sulfur and potassium levels also occurred, but were usually not statistically significant. Significant reduction in sulfur levels occurred only in the cementum following treatment with CP and SP. Sulfur levels increased significantly following treatment with NS. Significant reduction in potassium levels occurred only in the dentin following treatment with CP. It is concluded that bleaching materials may adversely affect the dental hard tissues and should be used with caution.

Borates↗

PubMed1996

Partial expression of the Papillon-Lefèvre syndrome in 2 unrelated families.

The Papillon-Lefèvre syndrome (PLS) is a rare, autosomal recessive trait that is characterized by palmar plantar keratosis (PPK) and severe, early onset periodontitis, affecting both deciduous and permanent dentitions. The clinical presentation of PLS is variable; the disease occurs so infrequently as to limit clinical cases for study. The exception is a few families with extensive consanguinity in which numerous cases occur. Of particular interest to mapping the genetic origin of the syndrome is the co-expression of the major traits of hyperkeratosis and periodontitis, and their severity. In this paper, we report 2 families with multiple affected individuals from geographically remote areas. A large extended family, from the Cochin region of India, currently residing in Israel, in which there is documented consanguinity and a family from the southwest region of Germany. In each family, 1 individual presents with hyperkeratotic lesions with the complete absence of periodontal lesions. Further, the difference in severity of the hyperkeratotic lesions between families is marked, and one sibling in the German family expressed rapid, early onset periodontitis in the absence of PPK. The genetic nature and penetrance of the genetic defect are discussed.

Adult↗

PubMed1996

Protection against endotoxic shock and lipopolysaccharide-induced local inflammation by tetracycline: correlation with inhibition of cytokine secretion.

Septic shock results from excessive stimulation of host immune cells, particularly monocytes and macrophages, by lipopolysaccharide (LPS) released from gram-negative bacteria. Macrophage-derived cytokines, such as tumor necrosis factor alpha (TNF-alpha) and interleukin-1beta (IL-1 beta), have been identified as central mediators in the pathogenesis of septic shock and the resultant mortality. Therefore, these cytokines were targets for experimental therapy for septic shock. Because of tetracycline's ability to intervene in cellular mechanisms involved in cytokine secretion, we tested the effect of tetracycline on LPS-induced septic shock and inflammatory lesions in mice. Tetracycline was found to protect mice against LPS-induced lethality and to abolish clinical signs of LPS-induced inflammatory lesions. This protection correlates with tetracycline's ability to reduce LPS-induced TNF-alpha levels in serum. Furthermore, tetracycline was found to inhibit LPS-induced TNF-alpha and IL-1 beta secretion, but not cytokine mRNA accumulation, in human monocytes in vitro. The results presented here suggest that tetracycline is a potent drug for LPS-induced pathology and that its mechanism of action involves blockage of posttranscriptional events of cytokine production.

Animals↗

PubMed1996

Human monocyte response to cementum extracts from periodontally diseased teeth: effect of conditioning with tetracycline.

Monocyte inflammatory cytokines, such as TNF alpha and IL-1 beta, have been implicated in the pathogenesis of periodontal destruction. The present study was designed to test the ability of extracts of cementum from periodontally diseased teeth to induce the secretion of these mediators by monocytes, to evaluate the role of adsorbed endotoxin in this process, and to test the effect of cementum conditioning with tetracycline on the monocyte response. Human monocytes were incubated with varying concentrations of cementum extracts, and TNF alpha and IL-1 beta levels in the media were measured. The results showed that while extracts of healthy cementum had no effect on monocyte secretion, concentration as low as 0.5 mg/ml of cementum from diseased sites raised the levels of TNF alpha and IL-1 beta secretion 10-fold. This response was dose-dependent. Diseased cementum were found to contain 1.5 ng/mg endotoxin, while endotoxin was not detectable in the extracts of the healthy cementum. However, neutralization of the endotoxin by polymyxin B only partially reduced the monocyte secretory response by 50 to 70%, suggesting that other factors in the extracts are also involved in monocyte stimulation. To simulate the effect of root conditioning, cementum was first agitated in a tetracycline or control solution prior to its extraction in media. Pretreatment of diseased cementum with tetracycline (50 mg/ml) was found to block the secretion of TNF alpha from cementum-stimulated monocytes. Pretreatment of the diseased cementum with 10 mg/ml tetracycline was not more effective than saline and HCI controls, with all treatments reducing cytokine secretion by approximately 80%. The direct addition of tetracycline to cementum-stimulated monocyte culture was found to block TNF alpha secretion in a dose dependent manner. The results suggest that extracts from diseased cementum are potent stimulators of monocyte secretion, and that endotoxin as well as other factor(s) appear to be involved. These factors are partially extracted by washing and a 10 mg/ml tetracycline solution is not more effective than saline in achieving this goal. In addition, tetracycline was found to be a potent inhibitor of TNF alpha secretion by cementum-stimulated monocytes, suggesting a novel mechanism for this drug in periodontal therapy.

Analysis of Variance↗

PubMed1996

The clinical effect of a newly designed electric toothbrush on supragingival plaque, gingivitis and gingival bleeding.

A clinical study was carried out in an attempt to assess the efficacy of a newly designed electric toothbrush compared to a conventional manual toothbrush using the American Dental Association's protocol for evaluating toothbrushes. An Oral-B 35 manual toothbrush, which served as the control, was compared to the Plaq & White125 electric toothbrush. Examinations were performed by two calibrated examiners at baseline, day 15 and day 30. Examinations included the gingival index, plaque index and bleeding index. Mean indices were calculated and compared between the two brushes using the repeated measures multiple analysis of variance. No statistically significant differences between the mean indices on the three examination days were observed following the use of the manual or the electric toothbrushes. The results of this study demonstrate that the electric toothbrush was numerically more effective than the manual toothbrush in reducing supragingival plaque levels, either before or after brushing, at each examination date compared to baseline plaque values. However, this difference was not statistically significant. This and other findings concluded that the Plaq & White toothbrush is comparable to the control ADA-accepted toothbrush.

Adult↗

PubMed1995

Efficacy of XeCl 308-nm excimer laser in reducing dye penetration through coronal dentinal tubules.

The efficacy of XeCl excimer laser irradiation in reducing dye penetration through human coronal dentinal tubules was studied. The roots of 20 freshly extracted human molars were resected, and the apical aspect of the crowns was ground until the pulp chamber was completely exposed. Following total removal of the pulp chamber and further grinding of the occlusal and apical surfaces up to the intact dentin, the teeth were randomly divided into experimental and control groups of 10 each. The teeth in the experimental group were completely coated with nail polish and then irradiated with XeCl 308-nm excimer laser at a fluence of 0.7 J/cm2 to form an elliptical lased area. The teeth in the control group were also coated with nail polish, but with a similar elliptical spot of exposed dentin corresponding to the irradiated spot created in the lased teeth left uncoated. All specimens were placed in 0.5% methylene blue dye for 48 h, rinsed, and air-dried. The specimens were then ground to reach the experimental area in order and photographed. The total area of penetrated dye was determined by three independent evaluators and then measured with a computerized planimeter. The mean total areas (mm2) measured in the lased specimens were significantly smaller than those in the controls (p = 0.012).

Dental Leakage↗

PubMed1995

Effect of preflaring on tactile detection of the apical constriction.

The efficacy of tactile detection of the apical constriction in flared and nonflared root canals was examined in 120 root canals of adult patients. In 68 nonflared (group 1) root canals, a #15 or #20 K-file was used to detect ("feel") the apical constriction. In 52 teeth (group 2), Hedstrom files, Gates Gliden drills #2 to #4, and ultrasonic files were used to enlarge the canal orifice and flare the coronal portion of the root canals before testing the apical constriction. After placing a #15 or #20 file in each root canal, a radiograph was taken, and the distance between the tip of the file and the radiographic apex was measured. The location of the file tip was classified into three categories: (a) within 1 mm short of the radiographic apex; (b) underextended, more than 1 mm short of the radiographic apex; and (c) overextended beyond the radiographic apex. In group 1 (nonflared), 32.3% of the root canals were classified in category a, as compared with 75.0% in group 2 (preflared). Over 26% of the root canals in group 1 and approximately 4% of the canals in group 2 were included in category b. Files inserted in preflared root canals had a significantly lower incidence of overextension than those placed in nonflared canals (21% versus 41%). The ability to determine the apical constriction by tactile sensation was significantly increased when the canals were preflared (p < 0.0001).

Adult↗

PubMed1995

Efficacy of argon laser irradiation in removing intracanal debris.

Endodontic instrumentation, irrigation, or intracanal medication are unable to totally remove intracanal debris. The purpose of this study was to evaluate the efficacy of argon laser irradiation in removing debris from the root canal system. After cleaning and shaping, 12 single rooted teeth were randomly divided into two groups of six teeth each. The first group, which served as the control, was not lased. In the second group, a 300 microns argon laser fiber optic was introduced into the root canal of each tooth, to its working length. Fifteen pulses of 100 msec each with an energy of 2 watts were delivered for 5 seconds at the apex. The lasing procedure was repeated at 1 mm intervals along the root canal, and the fiber tip was retrieved from the apex to the orifice. Computerized scanning electron microscopy analysis revealed that the amount of debris in the lased group was significantly lower than that in the control (p = 0.0001). On the basis of these results, it appeared that intracanal argon laser irradiation was an efficient mean of removing intracanal debris.

Argon↗

PubMed1995

Efficacy of XeCl-308 excimer laser in fusing hydroxyapatite to seal the root apex.

Sealing the root apex during apical surgery is important for a successful outcome. The effect of XeCl-308 nm excimer laser irradiation on the fusion and seal of hydroxyapatite to the root apex was tested in extracted human teeth. Twenty-four roots of intact single-rooted premolars were instrumented to size 30 K-file at the apex leaving a patent apical foramen. The apex of each tooth was covered with a freshly prepared paste of hydroxyapatite powder mixed with saline. The samples were then divided into two groups. In 12 teeth, the apical area was irridiated with XeCl-308 nm excimer laser at a fluence of 0.7 J/cm2 for 5 s with pulse repetition rate of 25 Hz and a spot size of 0.13 cm2 immediately after the hydroxyapatite application. In the other 12 teeth, no laser treatment was performed after the hydroxyapatite application. The roots were mounted on a model for the detection of radicular leakage of hydrogen peroxide. The hydrogen peroxide leakage of each sample was measured and the difference between the test groups compared. The ability of the hydroxyapatite plug to prevent hydrogen peroxide leakage at the apex was also tested by applying compressed air from the triple syringe on the coronal access preparation for 2 min. Apical leakage was found in four teeth in the lased group and in eight teeth in the non-plased group. However, the difference between the groups was not statistically significant. Compressed air applied to the coronal access caused hydrogen peroxide leakage in all the teeth.(ABSTRACT TRUNCATED AT 250 WORDS)

Chi-Square Distribution↗

PubMed1995

Effect of carbamide peroxide and hydrogen peroxide on the surface morphology and zinc oxide levels of IRM fillings.

The effect of 10% carbamide peroxide or 10% hydrogen peroxide on the surface morphology and zinc oxide levels of IRM fillings was tested. Ninety IRM samples were treated with either 10% carbamide peroxide, 10% hydrogen peroxide or phosphate buffer which served as control. Treatment consisted of placing the samples in a dry incubator at 37 degrees C for 1, 3 or 7 days. At each time point, the samples were removed from the test solutions, dried and prepared for surface scanning electron microscopy and energy dispersive spectrometric analysis. After 3 days, 10% carbamide peroxide significantly reduced the zinc oxide levels as compared to the 10% hydrogen peroxide group (<0.01) and the controls (p<0.01). 10% hydrogen peroxide reduced the zinc oxide levels similarly to the control. No significant changes in the zinc oxide levels were found between 3 and 7 days in any of the groups tested. Microscopy examination of the carbamide peroxide group revealed granular surface with well defined crystalline areas. In the hydrogen peroxide group, numerous cracks with multiple sun burst-like areas were found. At the macroscopic level, the samples of this group appeared cracked and more swollen, as compared to controls and samples treated with carbamide peroxide. In conclusion, both 10% carbamide peroxide and 10% hydrogen peroxide altered the surface morphology and the zinc oxide levels of IRM fillings, but their modes of action differed.

Carbamide Peroxide↗

PubMed1995

Occurrence of Actinobacillus actinomycetemcomitans and anti-leukotoxin antibodies in some members of an extended family affected by Papillon-Lefèvre syndrome.

Eighteen (18) members of an extended family in which numerous individuals have Papillon-Lefèvre syndrome (PLS) were examined. In all, 6 affected members and 12 non-affected members were included. All patients underwent a clinical examination which, in the dentate persons, included plaque index, bleeding on probing, probing depth, and periodontal attachment loss and a set of full mouth periapical x-rays. Subgingival bacterial samples were also collected from 2 teeth in the dentate patients for cultures and identification of Actinobacillus actinomycetemcomitans. Serum samples were collected from all participants and assayed for antileukotoxin antibodies. The results indicate that there is a high prevalence of leukotoxic strains of A. actinomycetemcomitans in persons suffering from PLS, as well as in unaffected family members. The ubiquitous presence of A. actinomycetemcomitans in the family units suggests a close association between A. actinomycetemcomitans and the periodontal disease associated with the syndrome; it also suggests that A. actinomycetemcomitans by itself is not sufficient for the expression of periodontal disease and that other factors, some of which must be genetic, are necessary for lesion development.

Adolescent↗

PubMed1994

Effect of hydrogen peroxide and sodium perborate on the microhardness of human enamel and dentin.

The effect of 30% hydrogen peroxide and a paste of sodium perborate mixed with hydrogen peroxide at different temperatures and time intervals on the microhardness of human enamel and dentin was examined. Intact extracted human teeth were sectioned, embedded in acrylic resin, polished, and divided into four test groups related to surface treatment. The groups were 30% hydrogen peroxide at 37 degrees C, 30% hydrogen peroxide at 50 degrees C in an illuminated chamber, a paste of sodium perborate mixed with hydrogen peroxide at 37 degrees C, and a paste of sodium perborate mixed with hydrogen peroxide at 50 degrees C in an illuminated chamber. Teeth treated with distilled water at either 37 degrees C or 50 degrees C served as controls. The results indicated that treatment with 30% hydrogen peroxide reduced the microhardness of both enamel and dentin. This reduction was statistically significant after 5-min treatment for the dentin and after 15-min treatment for the enamel (p < 0.05). Treatment with sodium perborate mixed with hydrogen peroxide did not alter the microhardness of either the enamel or dentin at the tested temperatures and time intervals. It is therefore suggested that the use of high concentrations of hydrogen peroxide for bleaching purposes should be limited. Sodium perborate appears to be a less damaging bleaching agent.

Borates↗

PubMed1993

Effect of ArF-193 nm excimer laser on human dentinal tubules. A scanning electron microscopic study.

The purpose of this study was to evaluate the effects of the ArF-193 nm excimer laser on the dentinal tubules of extracted human teeth under a scanning electron microscope. Fifteen 3 mm thick slices were cut with an electric saw at the cementoenamel junction from 15 extracted human teeth. A diamond bur was used to remove the cementum layer and expose the dentinal tubules. Each slice was scored by a permanent marker into four equal quadrants. The ArF excimer laser was applied for 5 seconds on three of the quadrants with fluences that ranged from 0.2 J/cm2 to 15 J/cm2 and pulse repetition of 25 Hz. The untouched quadrant served as a control. The specimens were mounted on stubs, sputter coated by gold, and examined by a scanning electron microscope. The effects of the ArF excimer laser irradiation varied. Laser fluences of 0.2, 0.5, and 1.0 J/cm2 had no effect. Although fluence of 15 J/cm2 caused significant removal of peritubular dentin, melting and resolidification of the dentinal smear layer was also observed under the scanning electron microscope with a laser fluence of 5 J/cm2.

Argon↗

PubMed1993

Sealing of human dentinal tubules by XeCl 308-nm excimer laser.

Root hypersensitivity occurs as a result of exposed dentinal tubules. Various methods and materials have been tried in an attempt to occlude these tubules. The purpose of this investigation was to study by scanning electron microscope the effects of XeCl excimer laser on exposed dentinal tubules of human extracted teeth. Fifteen 3-mm-thick slices were cut at the cementoenamel junction from 15 extracted human teeth by an electric saw. By using a diamond bur to remove the cementum layer the dentinal tubules were exposed. Each slice was scored by a permanent marker into four equal quadrants. Three of the quadrants were lased for 4 s by XeCl excimer laser with fluences ranging from 0.5 to 7.0 J/cm2 and pulse repetition of 25 Hz. The unlased quadrant served as control. The specimens were mounted on a stub, sputter coated by gold, and examined by scanning electron microscope. Nonlased surfaces showed numerous exposed dentinal tubules. In contrast, all specimens lased at fluences of up to 1 J/cm2 showed the presence of melted dentin which closed the dentinal tubules. At fluences of 4 J/cm2 and higher, rupture of molten materials and exposure of dentinal tubules were noted. The results indicate the application of XeCl excimer laser at specific fluences can cause melting of dentin and closure of exposed dentinal tubules.

Dentin↗

PubMed1993

Effects of the XeCl excimer laser on Streptococcus mutans.

The effect of XeCl excimer laser irradiation on the growth of Streptococcus mutans in liquid media and on agar plates was studied. Bacterial suspensions of S. mutans were placed in 96 wells of well culture plates. The contents of 72 wells (three experimental groups of 24 wells each) were lased for different time durations (2, 4, and 8 s). The remaining 24 wells were left unlased to be used as controls. Samples were withdrawn from all wells and examined for surviving bacteria. In addition, blood agar plates were inoculated with S. mutans and were lased with different energy densities (fluences). Zones of bacterial inhibition were measured. Analysis of variance test was used to determine statistical differences. The bactericidal effect of the laser applications was directly related to the amount of radiation time. Laser irradiation for 4 and 8 s resulted in bactericidal effect that was statistically significant compared with no treatment or to 2-s exposure. The effect of different energy levels was studied by irradiating inoculated blood agar plates. The zones of inhibition produced by higher energy levels (0.5 J/cm2, 0.7 J/cm2, and 1.0 J/cm2) were larger in comparison to the lowest fluence used (0.1 J/cm2). Application of the laser to the surface of the agar plates produced an indentation with a surrounding halo. The indentations and the zones of inhibition were more pronounced as the fluences increased. Based on our results it appears that the XeCl 308-nm excimer laser can kill S. mutans. This effect should be tested on other bacteria commonly present infected root canals.

Analysis of Variance↗