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Biomedical subjects

A H Kafrawy

Publications and source records attributed to A H Kafrawy.

At least 37 records · Page 2Linked to original sources
PubMed1991

Connective tissue reactions to glass ionomer cements and resin composites.

This study evaluated the histopathologic reactions of rat connective tissue to two glass-ionomer cements (Fuji Cap II, Fuji Ionomer Type III) and two microfilled light-cured composite resins (Helio-molar Radiopaque and Helioprogress). IRM (zinc oxide-eugenol cement) was used as a control. Discs of the materials, 5 mm in diameter and 2 mm thick, that had set for 15 minutes were implanted under the dorsal skin of 75 Sprague-Dawley rats. There were 15 rats in each group and each animal received two identical implants. Five rats from each group were terminated at 7, 28 and 85 days after implantation. Histologic sections of the implant sites were stained with hematoxylin and eosin. Findings at all study periods indicated that Fuji Ionomer Type III elicited more intense reactions than the other materials. Reactions to Fuji Cap II, Heliomolar Radiopaque and Helioprogress, at all study periods, were comparable to each other and to IRM.

Acrylic Resins↗
PubMed1990

Total calculus removal: an attainable objective?

The primary purpose of this study was to determine if two sessions of scaling and root planing, one using a "closed" approach and the other using an "open" approach, would remove all calculus from teeth with severe periodontal disease. Fourteen teeth (8 single-rooted, 6 multi-rooted) were treated by closed scaling and root planing with an ultrasonic instrument, and 17 others (10 single-rooted, 7 multi-rooted) were treated with hand instruments. After a healing period of 4 to 8 weeks, anesthesia was secured, periodontal flaps were raised, and the teeth were treated a second time using the same instrumentation as before. The teeth were then extracted and prepared for light microscopic evaluation. Twelve of the 14 teeth treated by ultrasonics and 12 of the 17 treated by hand instruments retained calculus. The two types of instruments had similar scores in the treatment of proximal root surfaces, furcal walls, and furcal summits. Hand instrumentation appeared to be more effective than ultrasonics in removing cementum from proximal surfaces, although this is not based on a formal statistical comparison of the two methods. Neither instrument was effective in removing cementum from the furcal walls or summits. Five randomly selected blocks containing remaining root structure were deparaffinized and prepared for scanning electron microscopy. One hand-instrumented specimen, which had not shown calculus with light microscopy, displayed calculus at the SEM level. All five specimens displayed residual calculus at either the light microscope, the SEM level, or both. The results of this study indicate that complete removal of calculus from a periodontally diseases root surfaces is rare.

Dental Calculus↗
PubMed1989

The effect of citric acid on retained plaque and calculus. A short communication.

Five extracted human teeth with clinically demonstrable calculus were used. One proximal surface of each tooth was partly scaled, leaving a small amount of calculus. The crown was then cut off at the cementoenamel junction and the scaled proximal surface was divided vertically into two segments using a thin separating disk. One segment was treated by rubbing cotton pellets soaked in citric acid (pH1) over the surface for three minutes and then immersing the segment in saline to stop the reaction. The other (control) segment was treated by rubbing cotton pellets soaked in saline over the surface for three minutes. When viewed under a scanning electron microscope, the control sections displayed scaling striations, considerable surface debris, and large numbers of bacteria at the borders of the residual calculus. Citric acid-treated specimens displayed little debris on cementum or residual calculus and virtually no bacteria at the junction between calculus and cementum. The surface morphology of the citric acid-treated calculus varied from layered-like to honeycomb.

Bacteria↗
PubMed1988

The effect of MPG on radiation-induced odontogenic tissue metaplasia.

This investigation monitored the effect of 2-mercaptopropionylglycine (MPG) in reducing radiation damage to the tooth-forming tissues. Fifty rats were exposed to x-ray doses of between 3 and 19 Gy directed toward the maxillary incisor germinal centers. Half of the animals were given an injection of MPG before irradiation, while the other rats were injected with saline solution. Administration of MPG did not significantly reduce the frequency of dentinal niche formation relative to the control teeth. The average lengths and percentage depths of the apicoincisal niches were statistically smaller in the groups treated with MPG. Although statistically significant, the mild protective effect of MPG was not clinically important because damage to the irradiated teeth was still extensive.

Amino Acids, Sulfur↗
PubMed1988

Comparison of meclofenamate sodium and hydrocortisone for controlling the postsurgical inflammatory response in rats.

The effectiveness of meclofenamate sodium and hydrocortisone in alleviation of local postsurgical swelling and leukocytic infiltration was compared at two postsurgical intervals in 60 male Sprague-Dawley rats. Both drugs were effective at 24 hours after surgery. Ten doses of 2 mg meclofenamate sodium administered over a 5-day period were more effective in reducing leukocytic infiltration than six doses of 2 mg hydrocortisone administered over the same period. Neither the hydrocortisone nor the meclofenamate sodium at the dosage used adversely affected osteoid formation.

Animals↗
PubMed1988

Evaluation of chemical protection against radiogenic osteodentin synthesis.

The effect of the radioprotector 2-mercaptopropionylglycine (MPG) in preventing the synthesis of radiation-induced osteodentin was examined. Fifty rats were exposed to single x-ray doses of between 3 and 19 Gy localized to the maxillary incisor growth centers. Half of the animals received an injection of MPG before irradiation while saline was administered to the other rats. MPG produced statistically significant reductions in the severity of osteodentin generation, but not its frequency, at some radiation levels. The nature of osteodentin and possible mechanisms of chemical radioprotection by MPG are discussed.

Amino Acids, Sulfur↗
PubMed1988

The effect of retained subgingival calculus on healing after flap surgery.

This study investigated the effects of retained subgingival calculus on healing of the periodontium at ten, 30 and 120 days. Eight beagle dogs between eight and ten years old with naturally occurring periodontal disease were used. One dog that died before any procedures were done provided information on the extent of gingival inflammation prior to surgery. Quadrants from seven dogs meeting the criteria for inclusion were selected, and each quadrant was randomly designated as either an instrumented or noninstrumented, surgical site. The gingival index for the selected sites was recorded along with clinical probing measurements. Instrumented sites were treated by reflection of a facial mucoperiosteal flap followed by thorough root planing. Non instrumented sites were treated by a facial mucoperiosteal flap alone. All flaps were returned to their preoperative position and secured with interrupted sutures. No antibiotics were given. Meticulous daily plaque control was begun the day after surgery and continued until sacrifice. There was a statistically significant reduction in gingival index scores for the 30- and 120-day instrumented sites and for the 120-day noninstrumented sites. Mean probing depths for the instrumented group showed a significant reduction at 30 and 120 days and for the noninstrumented group at 120 days after surgery. Forty percent of the noninstrumented roots and 10% of the instrumented roots displayed subgingival calculus. At all evaluation periods and in both instrumented and noninstrumented roots, inflammation was more intense when calculus was present; the difference was significant at ten days with the instrumented and at ten and 30 days with the noninstrumented specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

The effect of different treatment modalities on connective tissue attachment.

This study compared the effect of four treatment modalities on connective tissue attachment. Ligature-induced periodontitis was established around the mandibular premolars of five young beagle dogs over 8 weeks. Following a 2-week period without ligatures, a reference dog was sacrificed to estimate the extent and nature of the disease. Three dogs received flap procedures in one mandibular posterior segment, and the six experimental roots were treated with citric acid (pH 1) for 3 minutes; the contralateral mandibular segments received flap procedures and the roots were treated with 4% chlorhexidine gluconate in the Hibiclens preparation for 3 minutes. One segment of the control dog received flap procedures, and the roots were treated with sterile normal saline; the contralateral segment received closed root planning. The experimental dogs were sacrificed 1, 2 and 3 months after treatment. The control dog was sacrificed 3 months postoperatively. One week before sacrifice each dog received a Procion dye injection. At sacrifice the study segments of all four treated dogs were clinically healthy, with no observable differences between the different treatment modalities. Histologically, the 1, and 3-month chlorhexidine, the 3-month saline and 3-month root planed specimens had long junctional epithelial adhesions with little connective tissue attachment. The 2-month chlorhexidine and all citric acid-treated sections showed appreciable amounts of new connective tissue attachment. Some 2-month and 3-month citric acid and 2-month chlorhexidine sections showed cementum over the apical portion of the long junctional epithelium. The frequency of occurrence and the length of cementum overlapping epithelium increased appreciably over time.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Determination of the presence of root-bound endotoxin using the local Shwartzman phenomenon (LSP).

The purpose of these studies was to determine, by attempting to elicit the local Shwartzman phenomenon (LSP), if the material extracted from periodontally involved root surfaces is actually endotoxin or only an endotoxin-like substance. A total of 719 periodontally involved teeth and 201 unerupted third molars yielded pooled samples of root surface grindings which were treated with the endotoxin extraction technique nonpyrogenic saline or pyrogen-free water. In the first study each of the reconstituted extracts was injected into the right palatal gingiva of New Zealand white rabbits which had demonstrated the ability to elicit an LSP. Commercial Salmonella enteritidis endotoxin was injected into the left (control) palatal gingiva. This was followed 18 hours later by a provoking injection of 200 to 300 microgram S enteritidis endotoxin in a marginal ear vein. In the second study, reconstituted extracts were injected into the right side of the abdomen of New Zealand white rabbits. The left (control) side received varying amounts of S enteritidis endotoxin. Twelve hours later each animal received a provoking injection of 400 microgram of S enteritidis endotoxin in a marginal ear vein. In both studies the animals were examined 6 hours later for visual signs of an LSP. After sacrifice, the tissues were prepared and histologic sections evaluated by two examiners who were unaware of how the specimens had been treated. The results indicated that a heat-stable, phenol-water extractable and highly irritating substance could be obtained from periodontally involved root surfaces. However, it is questionable if the substance extracted was actually endotoxin. If a true endotoxin, it was present only in extremely small amounts.

Adolescent↗
PubMed1984

The effectiveness of hand versus ultrasonic instrumentation in open flap root planing.

The primary purpose of the study was to determine if, with an open flap approach, ultrasonic or hand instrumentation could remove all calculus from previously untreated teeth with moderate to severe loss of attachment. To be included in the study, teeth had to have at least 5 mm of attachment loss, be scheduled for extraction and be graded 2 or 3 on the Calculus Index of the Periodontal Disease Index system. Under local anesthesia, full-thickness, envelope-type flaps were elevated apical to the crest of bone to allow access to the root surfaces which were then treated with hand or ultrasonic instrumentation until the roots felt hard and smooth to a Hartzell explorer. The teeth were then removed, rinsed, and lightly scrubbed to remove debris and a No. 14 wheel bur was used to place a groove along the coronal extent of the connective tissue attachment. A stereomicroscope at magnification X 4.6 was used to quantitate the percentage of residual calculus on 25 teeth treated by each method. Overall, hand-scaled root surfaces demonstrated less residual calculus (5.78%) than ultrasonically treated surfaces (6.17%). Twenty teeth treated by each method were then prepared for histologic evaluation and evaluated under the light microscope at magnification X 100 for residual calculus and relative smoothness. Residual calculus was found on four ultrasonically and 12 hand-treated teeth and was almost evenly distributed between anterior and posterior teeth for both methods. The finding of considerably less calculus on histologic than on stereomicroscopic examination may have been due to the loosening of deposits by instrumentation, especially ultrasonic vibration, and their subsequent release during histologic preparation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Pocket epithelium removal via crestal and subcrestal scalloped internal bevel incisions.

This study assessed the extent of pocket epithelium removal by crestal and subcrestal scalloped inverse bevel incisions during mucoperiosteal flap surgery. Fifty-six gingival biopsies were obtained from 52 participants, who had extractions of periodontally involved teeth. Sulcular incisions which severed the epithelial attachment served as controls. Experimental scalloped internal bevel incisions were made: (1) at the gingival crest extending apical to the osseous crest (crestal incision) and (2) 1 to 2 mm apical to the gingival margin extending apical to the osseous crest (subcrestal incision). In the two procedures the initial incisions were followed by sulcular incisions to sever the epithelial attachment. After both crestal and subcrestal incisions full thickness flaps were reflected, pocket contents were removed, and flaps were replaced against the teeth. Gingival biopsies were then obtained from control and experimental sites followed by extraction of teeth. All specimens were processed, embedded in paraffin, sectioned, stained with hematoxylin and eosin and examined for residual pocket epithelium. Control incisions eliminated pocket epithelium in two of 20 specimens. Crestal incisions eliminated pocket epithelium in 11 of 25 areas, while subcrestal incisions eliminated pocket epithelium in 13 of 25 areas. All 10 papillary areas treated by crestal incisions and 8 of the 10 papillary areas treated by subcrestal incisions displayed residual pocket epithelium. Neither crestal nor subcrestal scalloped internal bevel incisions consistently eliminated all pocket epithelium.

Adult↗
PubMed1984

Relative resistance of long junctional epithelial adhesions and connective tissue attachments to plaque-induced inflammation.

This study compared the resistance to periodontal disease of the long junctional epithelial adhesion and the naturally occurring dentogingival junction. Two groups were used, each containing three young male beagle dogs with all permanent teeth erupted. Periodontitis was induced around maxillary and mandibular premolars in the experimental dogs over a 42-day period, using subgingival ligatures and a soft diet. Fourteen days after ligature removal, flaps were reflected, granulation tissue was removed and the roots were planed to the alveolar crest. Reference grooves were placed in the root surfaces at the level of the alveolar bone, the flaps were positioned over the alveolar crests, and sutures were placed. A 60-day period permitted healing with formation of long junctional epithelial adhesions. During this 116-day period control dogs were maintained in gingival health by daily brushing and by prophylaxis every 14 days. Both groups had a high level of health (GI scores of 0) at the beginning of the 20-day combined disease phase. Inflammation was induced in both groups by subgingival ligature placement and a plaque-promoting diet. Right and left sides of both groups represented separate time intervals within the 20-day period. Block sections were secured at time of killing and the tissues were prepared for light and fluorescent microscopic evaluation. Mean GI scores and mean probing depths increased similarly in both groups. Tagge index scores of gingival inflammation were higher at the longer time periods in the experimental animals. However, they displayed an intact long junctional epithelial adhesion throughout the study, while control animals frequently showed ulceration of the sulcular epithelium. Neither group showed significant changes in location of the apical cells of the attachment epithelium. Crestal osteoblastic activity, confirmed with Procion labeling, predominated in the experimental animals, while osteoclastic activity predominated in the control. Under the conditions of this study, there appeared to be no appreciable difference in resistance to disease between a long junctional epithelial adhesion and a true connective tissue attachment.

Alveolar Process↗
PubMed1983

A scanning electron microscope study of the effects of various agents on instrumented periodontally involved root surfaces.

This study evaluated the effects of chemical and biologic agents on periodontally diseased root surfaces which had been scaled or root planed. The proximal surfaces of 25 teeth were scaled to remove all visible calculus, and the proximal surfaces of another 25 teeth were vigorously root planed to remove all cementum and to achieve a hard, smooth, glass-like surface. Five scaled and five root planed specimens were randomly selected for light microscopic examination to determine the amount of cementum removed. Cementum remained on all scaled surfaces but root planing had removed most of the more coronal cementum. Each of the 40 remaining teeth (20 scaled and 20 root planed) was longitudinally sectioned to obtain an experimental and control specimen. Four scaled and four root planed sections were randomly selected as experimental specimens for a test of each of the following five agents: (1) saturated citric acid for three minutes; (2) 15% EDTA for 5 minutes; (3) sodium hypochlorite for 5 minutes, followed by a 30-second application of 5% citric acid; (4) sodium hypochlorite alone for 5 minutes; and (5) 2% sodium deoxycholate (NAD) for 1 minute, followed by a 1-minute rinse in distilled water, and then a 1-minute application of 5% Cohn's fraction IV1. The control for each experimental specimen was treated with saline. All samples were prepared for SEM and examined at 3,000 X. Areas of particular interest were also examined at 12,000 X. The chemical treatments exposed only individual collagen fibers or irregular fiber bundles on the scaled surfaces. Saturated citric acid, EDTA, and sodium hypochlorite with citric acid neutralization removed debris and exposed openings in the root surfaces. Sodium hypochlorite alone and NaD/Cohn's fraction IV1 were less effective in removing surface debris and had an effect similar to that seen in the saline controls. Application to root planed specimens of saturated citric acid, EDTA, and sodium hypochlorite followed by 30 seconds of citric acid neutralization resulted in surfaces virtually free of debris and with numerous collagen fibers exposed on the surface. EDTA appeared to cause a morphologic change in the collagen fibers. Sodium hypochlorite alone, sodium deoxycholate followed by Cohn's fraction IV1, and physiologic saline were relatively ineffective in surface debridement.

Adult↗
PubMed1983

Total cementum removal: a realistic objective?

The purpose of the study was to determine if total cementum removal from periodontally involved root surfaces was a clinically realistic objective. The experimental specimens were 36 periodontally involved teeth, extracted because of advanced periodontal disease. Eighteen teeth were from patients under age 36 while the other 18 were from patients over 36. All teeth had at least 6 mm of attachment loss on the proximal surface tested and showed no evidence of forceps damage. After removing all visible calculus, equal numbers of each tooth type in each age group were given 50 planing strokes with either a Jacquette scaler, a Gracey curet, or an Indiana University curet. Following the planing procedure the specimens were fixed, decalcified, and 7 microns thick sections prepared and stained with hematoxylin and eosin. Two teeth were excluded from the evaluation due to poor orientation. In none of the remaining 34 teeth was cementum totally removed over the entire proximal test surface. There was no apparent difference between the instruments in the amount of residual cementum found. Larger amounts of residual cementum were seen in more apical areas in both age groups.

Adult↗
PubMed1983

Biologic considerations in the selection and use of restorative materials.

In this article the defense mechanisms of the pulp and pulp reactions to injury were briefly reviewed. Iatrogenic pulp injury was emphasized and guidelines for prevention of such injury were provided. These could be summarized as follows: Never cut dry. Always use a water coolant to prevent heat generation and desiccation of dentin. Use a protective base or liner with materials that are known to be irritating to the pulp (groups II and III) regardless of cavity depth. Use a protective base in all deep cavities where the possibility of a microscopic exposure of the pulp exists, regardless of the nature of the material to be used for restoration.

Dental Materials↗