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Biomedical subjects

A Stabholz

Publications and source records attributed to A Stabholz.

At least 55 records · Page 3Linked to original sources
PubMed1993

Antimicrobial properties of human dentin impregnated with tetracycline HCl or chlorhexidine. An in vitro study.

Substantivity of tetracycline HCl and chlorhexidine digluconate to human root dentin was assessed in vitro. 51 extracted single-rooted teeth, their crowns removed, were assigned to 1 of 4 treatments in groups of 12. A control groups included 3 roots. Each group was divided into 3 subgroups to allow evaluation of drug exposure for 1, 3 or 5 min. The roots were immersed in tetracycline HCl (10 or 50 mg/ml) or chlorhexidine digluconate (0.12 or 0.2%) solutions following root planning. Control roots were immersed in sterile saline (0.9%). Following drug immersion, the roots were transferred to tubes containing 2 ml tris buffered saline. The tubes were incubated at room temperature for 22 days. Desorption media were replaced at 24-h intervals. Removed media were examined for antimicrobial activity using a microtiter assay in which bacterial growth was evaluated by optical density readings. Roots immersed in tetracycline HCl 50 mg/ml released antimicrobial activity to successive desorption media for 14 days. Tetracycline HCl 10 mg/ml activity lasted 4 days. Roots subjected to chlorhexidine digluconate released antimicrobial activity for 24 h only. Within each treatment, there were no differences between the 3 exposure intervals of 1, 3 or 5 min. Our findings suggest usage of the periodontally exposed instrumented root as a depot for sustained release of tetracycline HCl, but not chlorhexidine digluconate, to the subgingival environment. The substantiveness of tetracycline HCl seems related to drug concentration rather than the exposure interval. Clinical trials are needed to confirm the clinical significance of these in vitro observations.

Adsorption↗
PubMed1993

Retention of antimicrobial activity by human root surfaces after in situ subgingival irrigation with tetracycline HCl or chlorhexidine.

Substantivity of tetracycline HCl and chlorhexidine digluconate was assessed in extracted teeth. Fifty periodontally compromised teeth scheduled for extraction with probing depths ranging between 6 and 12 mm were root planed and then irrigated in situ with 1 of 4 solutions: tetracycline HCl at concentrations of 10 or 50 mg/ml, 0.12% chlorhexidine digluconate, or 0.9% sterile saline. Each tooth was exposed to 150 ml of the respective irrigation solution. Following extractions, the teeth were transferred to tris buffered saline and incubated at room temperature for 22 days. Incubation solutions were replaced at 24-hour intervals. Removed solutions were examined for desorbed antimicrobial activity using a microtiter assay in which bacterial growth was evaluated by optical density readings. Tetracycline HCl 50 mg/ml exhibited significantly greater antimicrobial activity than chlorhexidine digluconate for 12 days and greater than saline for 16 days. Tetracycline HCl 10 mg/ml exhibited significantly greater antimicrobial activity than chlorhexidine digluconate and saline for 4 days. Chlorhexidine digluconate did not exhibit any significant antimicrobial activity at any time point. Our findings demonstrate long-lasting substantivity of tetracycline HCl, but not chlorhexidine digluconate, by teeth exposed to a single episode of pocket irrigation of their periodontally-exposed roots. The amount of antimicrobial activity retained is proportional to the concentration of tetracycline HCl used for irrigation.

Adsorption↗
PubMed1992

Effects of Nd:YAG laser on apical seal of teeth after apicoectomy and retrofill.

The application of Nd:YAG laser to tooth surface can change its surface permeability. The purpose of this study was to investigate the effects of Nd:YAG laser on the permeability of dentin following apicoectomy and retrofill. Sixty single-rooted teeth were randomly assigned to six groups of 10 teeth each. The six groups were arranged in three pairs, experimental and control groups. The canals of teeth in pairs 1 and 2 were cleaned, shaped, obturated, and their apical 2 mm were resected. A class I preparation was prepared and filled with amalgam in each tooth in pair 1. The apical 2 mm of each tooth in pair 3 was removed, and a class I preparation was prepared and filled with amalgam. The apical surface of resected roots in half of the samples in each pair was lased twice by using Nd:YAG laser. The duration of lasing and the number of pulses were recorded for each tooth. After application of nail polish to the unoperated surface of each tooth, the teeth were placed in 0.5% methylene blue dye for 48 h. The amount of dye penetration in sagittal sections of each tooth was measured. The amount of dye penetration was significantly lower in lased roots than in nonlased ones (p < 0.05). Based on our results, it appears that application of Nd:YAG laser reduces the permeability of resected roots.

Analysis of Variance↗
PubMed1992

Scanning electron microscopic study of the apical dentine surfaces lased with ND:YAG laser following apicectomy and retrofill.

The purpose of this investigation was to study the effects of a Nd:YAG laser on the cut surface of teeth using scanning electron microscopy (SEM). Eighteen single-rooted teeth were cleaned, shaped, and obturated with gutta-percha and root canal sealer. The apical 3 mm of each tooth were resected with a diamond fissure bur, and the teeth were randomly divided into two groups of nine teeth each. The resected surface of each root in one group was lased twice. The duration of lasing and the number of pulses were recorded for each tooth. The teeth were air dried, mounted on stubs, sputter-coated with gold-palladium and examined under SEM. Application of the Nd:YAG laser caused melting of apical dentine surfaces. The melted material resembled the appearance of glazed interconnected droplets. Resolidification and recrystalization of the melted areas appeared to be incomplete and discontinuous. Some areas between the glazed regions appeared similar to those of non-lased apical dentine resected root surfaces.

Apicoectomy↗
PubMed1992

Effect of cervical coating of ethyl cellulose polymer and metacrylic acid copolymer on the radicular penetration of hydrogen peroxide during bleaching.

Extraradicular leakage of oxidizing agents during bleaching is an undesirable event and thus need to be prevented. The effect of external cervical coating of ethyl cellulose (EC) and metacrylic acid copolymer (MAC) on the radicular penetration of hydrogen peroxide during intracoronal bleaching was examined. Single rooted human premolars extracted for orthodontic reasons were used. The cementum covering the cemento-enamel junction was mechanically removed and the teeth treated endodontically and bleached with 30% hydrogen peroxide. Radicular hydrogen peroxide penetration was measured before coating the teeth and after applications of 1-3 layers of EC or 3 layers of MAC external cervical coatings. It was found that the radicular penetration of 30% hydrogen peroxide was related to the number of layers of cervical EC coatings. Application of one layer of EC did not reduce the hydrogen peroxide penetration. Two and three layers of EC reduced the hydrogen peroxide penetration by 38% and 85% respectively. Three layers of MAC reduced the radicular hydrogen peroxide penetration in 83%. Statistically, a highly significant difference was found between the teeth coated with three layers of either EC or MAC and the noncoated teeth (p < 0.001). It was concluded that application of ethyl cellulose or metacrylic acid copolymer to exposed cervical root surfaces may effectively prevent extraradicular leakage of bleaching agents.

Cellulose↗
PubMed1992

[Lasers in endodontics].

Laser technology has been developed rapidly in the last decade. New lasers with a wide range of characteristics are available now which are being used in various branches of dentistry. The application of these new technologies in endodontics has always been challenging. Today more experience and knowledge in applying lasers in endodontics is available.

Animals↗
PubMed1991

The use of sustained release delivery of chlorhexidine for the maintenance of periodontal pockets: 2-year clinical trial.

The release of chlorhexidine from an ethyl cellulose-based dosage form (SRD) has been shown to be effective in the reduction of the flora associated with periodontal pockets as well as in reducing probing depths. In this study, treatment with this dosage form was compared to routine maintenance therapy (RMT) in a 2-year, split mouth clinical trial. Ten patients with 84 pockets greater than or equal to 5 mm who had not received any periodontal therapy or systemic antibiotics over the last 6 months were included. The patients all received a full mouth scaling and root planing together with through oral hygiene instruction. Two months later (baseline) plaque index (P1I), bleeding on probing (BOP), pocket probing depth (PD), and attachment levels (AL) were assessed at all selected sites. Pockets on the control side then received RMT while the experimental pockets were treated with the SRD only. Treatment was repeated every 3 months for 2 years. The SRD treatment resulted in an improvement of greater than or equal to 3 mm in PD of at least 1 pocket in 8 of 10 patients, while RMT resulted in a similar improvement in only 1 of 10 patients (P = 0.012). Similarly a gain of attachment of greater than or equal to 3 mm was found in at least 1 SRD pocket in 8 of 10 patients. The RMT resulted in a similar improvement in only 2 patients (P = 0.012).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Endodontic retreatment--case selection and technique. 3. Retreatment techniques.

The necessity to remove filling materials from the root canals is one of the major differences between primary endodontic therapy and retreatment. The obturating material has to be removed from the root canals before routine endodontic therapy can be performed. The removal of the material should not result in a change in the canal morphology, so that the objectives of endodontic therapy can be maintained. Numerous techniques may be used for removing filling materials and other obstructions from root canals. This article reviews the techniques that were suggested in the literature for this purpose and discusses their advantages and disadvantages.

Foreign Bodies↗
PubMed1990

The effect of sustained release application of chlorhexidine on salivary levels of Streptococcus mutans in partial denture wearers.

The effect of a slow-releasing dosage (SRD) coating of chlorhexidine on the salivary levels of Streptococcus mutans and on plaque index scores in patients with removable partial dentures (RPD) was tested. The SRD proved to be effective in maintaining a low level of S. mutans counts after mechanical cleaning, as compared to a baseline established during the control period. Plaque index scores were lower following the treatment and correlated with the microbiological results. Our findings indicate that a single application of sustained-release chlorhexidine to removable partial dentures effectively maintains S. mutans levels as well as reducing the plaque score for a minimum period of 1 week.

Chlorhexidine↗
PubMed1990

Effect of benign familial neutropenia on the periodontium of Yemenite Jews.

The purpose of this study was to compare the periodontal status of Yemenite Jews with and without benign familial neutropenia (BFN). Thirty-four volunteers were examined at baseline and after 3 years. Plaque index (PlI), bleeding index (BI) probing depth (PD), and attachment levels (AL) were recorded. Differential blood counts were done on at least three occasions during the study. Volunteers with at least one count of less than 2000 neutrophils were considered neutropenic. The majority of patients received oral hygiene instructions and scaling at the initial visit. During the study there was a significant drop in PlI (P less than 0.01) and BI (P less than 0.05). At baseline the BFN and non-BFN volunteers had similar PlI, but the BI was significantly greater in the BFN group. At follow-up, there was a significantly greater number of teeth with pockets greater than or equal to 6 mm in the BFN group (P less than 0.05). These results indicate that volunteers with BFN, a phenomenon that has not previously been associated with any pathology, are more susceptible to gingival inflammation and attachment loss than unaffected volunteers and that they respond more favorably to an improvement in oral hygiene.

Adult↗
PubMed1990

Success rate in endodontics.

Over the thirty years since Strindberg's comprehensive study, much effort has been invested in an attempt to formulate a clear-cut answer to the basic question: What is the success rate in endodontics? The discrepancy and disagreement as reported in the endodontic literature with regard to success rate and the influence of the various factors on treatment results, prompted us to engage in a thorough analysis of the major causes for the variability of the reported data. These causes are related to the design of the studies, the endodontic techniques employed in them, the qualifications of the operators performing the treatment and the complexity of the included cases. They are also related to the observation period in each study, as well as to the criteria that were used for evaluating the treatment results.

Dental Pulp Diseases↗
PubMed1989

Use of a metastabilized chlorous acid/chlorine dioxide formulation as a mouthrinse for plaque reduction.

A metastabilized chlorous acid/chlorine dioxide (MECA) formulation was used as a mouthwash in a group of 18 volunteers aged 20-27. Its effect on developing plaque and salivary bacterial count was tested. The trial was carried out over 33 days during which each subject used three different formulations of mouthwash: a high concentration (0.16% sodium chloride in an activating system), a low concentration (0.04% sodium chloride, comparably activated) and a placebo mouthwash (activating system alone). Each participant used each of the three formulations as the only means of oral hygiene for 5-day periods. Each experimental period was separated by 9 days during which the participants returned to their regular oral hygiene habits. The high concentration and low concentration groups showed a 34.5 and 13.5% reduction of dental plaque scores, respectively, compared with the placebo control group. This effect on the plaque index scores was not accompanied by any significant change in the number of salivary bacteria.

Adult↗
PubMed1989

The anticariogenic activity of glycyrrhizin: preliminary clinical trials.

A clinical trial to test the compound glycyrrhizin, the sweet component of licorice, was conducted on 21 dental students. A split-mouth technique of glycyrrhizin application was used. Subjects were instructed to discontinue all oral hygiene procedures, but no dietary modifications were imposed. After 3 days a highly significant reduction in plaque was detected in the upper central incisors on the experimental sides compared with the control sides of students' mouths. Comparing all teeth, less plaque was found on experimental sides than on control sides of the mouths. This difference demonstrated a tendency towards statistical significance. After 4 days the quantitative differences between the two halves of the mouths (less plaque on experimental sides) were greater than after 3 days. This pilot study might indicate the potential of glycyrrhizin in controlling dental plaque.

Adult↗