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Biomedical subjects

M P Levin

Publications and source records attributed to M P Levin.

At least 19 recordsLinked to original sources
PubMed1989

Rapidly progressive periodontal disease associated with HIV infection: report of case.

A case of rapidly progressive periodontal disease associated with human immunodeficiency virus (HIV) infection is presented. Rapid horizontal bone loss, with only moderate inflammation, occurred during a 13-month period. Pocket depth was significantly less than anticipated, given the degree of bone loss. The patient had no signs or symptoms of acquired immune deficiency syndrome (AIDS). The cause, features, diagnosis, and management are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Bioceramic implants in surgical periodontal defects. A comparison study.

The healing response of two commercially available bioceramics, beta tricalcium phosphate (TCP) and hydroxylapatite (HA), was compared after implantation in surgically created defects in dogs. Three 18 to 24 month old female Labrador dogs were used. Under general anesthesia 3-wall defects were created on the canines and premolars. The roots were planed, and reference notches were placed to identify the alveolar crest and the apical extent of the defects. TCP or HA was placed in alternating canine defects. The premolars received no implants and served as controls. Plaque management was accomplished by biweekly brushing with 0.2% chlorhexidine. Following healing periods of 5, 12 and 16 weeks, the dogs were sacrificed and perfused with 10% formalin. Six-mu step serial sections were evaluated by light microscopy. Healing against the root planed surface varied from a long junctional epithelium to a connective tissue reattachment in new cementum. TCP particles were actively resorbed by giant cells and macrophages and were incorporated into new bone matrix. The HA particles were encapsulated by fibrous connective tissue and rarely seen in contact with repairing bone. Bone formation was slower around HA particles at all time periods. Some evidence of HA particle resorption was seen at each time period.

Alveolar Process↗
PubMed1984

Alloplastic implants of tricalcium phosphate ceramic in human periodontal osseous defects.

Initial pilot studies using tricalcium phosphate ceramic placed into human periodontal osseous defects demonstrated osseous repair. Therefore, further evaluation of this material was undertaken on 17 carefully selected patients with 1-wall, 2-wall, crestal and furcation defects using standardized preoperative and postoperative radiographs, clinical measurements and clinical photographs. Inverse bevel, full-thickness flaps were raised, the areas debrided, root surfaces planed with ultrasonic and hand instrumentation, osseous penetrations made with curet point and the flaps sutured after the defects were filled. Eighteen-month reentry surgical procedures were performed on 10 of the 17 patients, with a resultant average of 2.8 mm of new bone. Controls were not used in this study since a protocol describing a sham procedure with other than 3-wall osseous defects was not acceptable in 1973 to the Clinical Human Use Committee. Although the tricalcium phosphate ceramic material was not found to be totally predictable in this study, it may nevertheless become a useful graft material because of its potential for osseous repair in combination with its availability, host acceptability, ease of manipulation and storage advantages.

Alveoloplasty↗
PubMed1979

Healing of the oral mucosa with the use of collagen artificial skin.

Wounds were prepared in the oral cavity of 15 rabbits and five dogs, and an enzyme-solubilized calfskin collagen was placed over the surgery sites on one side. The contralateral sides acted as controls. Results indicated that the membrane was biologically acceptable to the oral mucosa of rabbits and dogs. Th collagen did not cause any adverse reaction and may have been responsible for the clinical impression of slightly more rapid healing of the gingivae in dogs. Clinical implications of this material's utilization produce some exciting ideas for future research.

Animals↗
PubMed1978

Submergence of roots for alveolar bone preservation. I. Endodontically treated roots.

Mandibular premolars in four dogs were endodontically treated and then totally submerged. Histologic and radiographic findings showed that this procedure should be considered as an alternative to extraction of key teeth in an effort to preserve alveolar bone. 1. Periodic follow-up on this procedure should be done to rule out cystic formation. 2. Beveling the coronal portion to the buccal is advocated to compensate for the thin buccal plate. 3. The procedure should be done in two steps to allow the root canal sealer to set, or an amalgam should be placed over the pulp canal. 4. New cementum and connective tissue will form over the coronal surface separating the dentin from new bone.

Alveolar Process↗
PubMed1978

Submergence of roots for alveolar bone preservation. II. Reimplanted endodontically treated roots.

Root canal therapy was accomplished on the mandibular premolars of four dogs. These premolars were then extracted, contoured, reimplanted, and submerged. Resorption occurred up to 60 days; healing progressed satisfactorily, with some evidence of coronal osseous regeneration. Root canal sealer was expressed out the coronal orifice after the roots were submerged. This sealer appeared to affect normal healing over the coronal surface of the roots.

Alveolar Process↗
PubMed1978

Effect of ultrasonic instrumentation on the retention of simulated cast crowns.

The effect of ultrasonic instrumentation on the retention of cemented cast restorations was studied. Forces required to dislodge castings from specimen assemblies subjected to ultrasonic vibrations did not differ significantly from those required to cause failure of noninstrumented specimens. The results indicate that clinical application of the ultrasonic device would not affect adversely the retention of properly cemented and well fitting cast restorations.

Crowns↗
PubMed1977

The effects of length of surgery on healing of full and partial thickness flaps.

Partial and full thickness flaps which were were made in the facial gingiva of 10 dogs were reflected for 15 or 90 min. Specimens were examined histologically and biochemically from 3 to 28 days after initial surgery. The results indicate that flaps refelected for 15 min exhibited faster epithelial closure than those reflected for 90 min. Partial thickness flaps reflected for both 15 and 90 min showed less inflammation than full thickness flaps at 3 and 7 days post surgery and healed faster in respect to epithelial closure, mesenchymal healing, and bone regeneration. Biochemical analysis of the collagen concentration of the tissure flaps revealed similar collagen content in full and partial thickness flaps reflected for 15 min; however, the collagen concentration of partial thickness flaps opened for 90 min was higher than that in full thickness flaps.

Animals↗
PubMed1977

Scanning electron microscope study of scalers.

Scanning electron microscopy was used to examine factory-sharpened, dulled, and resharpened scalers. The following observations were made: 1. The factory sharpened scalers exhibited metallic extensions from the lateral surface (wire edges). 2. The machine-resharpened instruments resulted in nonfunctional wire edges from the facial surface. Honing produced an exact meeting of facial and lateral surfaces. 3. Hand sharpening, using an Arkansas stone (grit 500) against the lateral surface away from the cutting edge, effected an exact meeting of the facial and lateral surfaces and no evidence of wire edges. 4. From this study an optimum cutting edge for a scaler is characterized as having a smooth, contiguous meeting of the facial and lateral surfaces free of wire edges. If a wire edge is present, it should be functional.

Dental Instruments↗
PubMed1977

The sharpening of scaling instruments: I. An examination of principles.

The theory and practice of sharpening with particular emphasis upon dental scalers and periodontal curettes have been discussed in Part I of this series. Various cutting modes and edge characteristics are described together with the special requirements they present in sharpening. Different approaches to sharpening are examined. Stressed are the advantages of using powered rotary stones on the sides of the blade instead of the blade face in sharpening scalers and curettes. Part II will describe the sharpening procedure--materials and technique--used and preferred by the authors.

Dental Instruments↗
PubMed1977

The sharpening of scaling instruments: II. A preferred technique.

The authors' preferred procedure for sharpening scalers and curettes is described in detail; powered rotary stones are used in grinding the sides of the blade. Selected sharpening materials are discussed and evaluated and the control and removal of edge burrs are described. A regular sharpening schedule is recommended, both to simplify sharpening and to extend the useful life of the armamentarium.

Dental Instruments↗
PubMed1976

Histologic features of the superior labial frenum.

Histologic examination was performed on the superior labial frenum obtained from 11 fresh biopsy and three autopsy specimens. The frena contained considerable dense collagen, loose connective tissue and elastic fibers. There were no muscle fibers in any of the frenum sections except the autopsy specimens, where it was seen in the vestibular tissue but not in the frenum proper.

Connective Tissue↗
PubMed1976

Assessment of attached gingiva using the tension test and clinical measurements.

The attached gingiva on the facial surface of the mandibular central incisors was evaluated by measurements and the "tension test" on 226 subjects between the ages of 8 and 22 years. Findings of significance were: 1. As age increased a definite increase in width of attached gingiva occurred. 2. There was no increase in the frequency of a positive tension test in older age groups. 3. No relationship was observed when results of the tension test were compared with clinical measurements of attached gingiva.

Adolescent↗
PubMed1976

A comparison of the mucogingival junction in dentulous and edentulous areas.

Thirty human mucogingival specimens were evaluated histologically and histochemically to determine whether a difference exists in the mucogingival junction of dentulous and edentulous areas of the maxilla and mandible. No significant differences were observed between the two areas. The presence of an intermediate zone is described, which may have clinical implications in some surgical procedures.

Adult↗