No abstract

Platelet-derived growth factor (PDGF) is a polypeptide growth factor considered to have a role in the proliferation and migration of fibroblasts at a wound healing site. The aim of this investigation was to determine if PDGF, when applied to root surfaces, would stimulate the proliferation of fibroblasts and further enhance regeneration. Six mongrel dogs with healthy periodontia were selected for this study. Using a closed wound surgical model, standardized 4 x 4 mm fenestration defects were created into dentin on the mid-facial of the mesial and distal roots of 4 mandibular posterior teeth in each quadrant. Each defect received either: 1) saline solution (C); 2) expanded polytetrafluoroethylene (ePTFE) membrane; 3) PDGF; or 4) ePTFE + PDGF. 3H-thymidine was administered 1 hour prior to animal sacrifice at 1, 3, and 7 days postsurgery. Each time period included 2 dogs with each dog undergoing the four different treatments. Slides were prepared for autoradiography. 3H-thymidine-labeled cells were counted and results were statistically analyzed using the Bonferroni (Dunn) t test on the SAS program. Results indicated PDGF enhanced fibroblast proliferation when compared to the groups without PDGF. Significant differences (P < 0.05) were noted at day 1 and 7 when PDGF and PDGF + GT were compared to C and GT groups. No significant differences were observed in labeled fibroblasts between the C and GT groups at any time period. These findings suggest that PDGF enhances fibroblast proliferation in early periodontal wound healing, whether used alone or in combination with the ePTFE membrane.

This study tested the effects of using a Gore-Tex periodontal material on new connective tissue attachment in beagle dogs with natural periodontitis. Seven female beagle dogs with advanced periodontitis were selected and given thorough root debridement. Under general anesthesia four weeks later, mucoperiosteal flaps were raised involving all mandibular premolars and first molars. Gore-Tex periodontal material was adapted to all premolars, and the flaps were sutured tightly, keeping the material covered. The first molars acted as controls, receiving only surgery. Some material was removed in one month, while other materials were removed eight to 10 weeks after surgery. All dogs were sacrificed at three months. After processing, descriptive histology and histometrics were carried out, evaluating new connective tissue attachment, bone response and epithelial downgrowth. Results were statistically analyzed, using paired t tests. They showed new connective tissue attachment with cementum deposition in areas where the material was used. Also, the epithelial downgrowth was reduced in these areas. In the controls, minimal connective tissue attachment was found, with the area healing by a long junctional epithelium. Statistical analysis showed significant differences (P less than 0.05) favoring experimental areas both in the increase of new connective tissue attachment and in the decrease of epithelial downgrowth. No differences were found between areas where the material was removed in one month or left longer in place. No difference in bone response was found. Gore-Tex material was effective in blocking gingival epithelial downgrowth and connective tissue proliferation, promoting new attachment according to the principle of "guided tissue regeneration."

No abstract

Two young adult rhesus monkeys, with an average weight of 12 pounds were used. Anesthesia with Nembutal 30 mg/kg of body weight was given to perform the surgeries. Artificial defects were created by raising a flap and removing about 5 X 7 mm of the buccal alveolar plate and suturing the flaps exposing the alveolar crest. These defects were left untreated for 2 months. Then, mucogingival lateral sliding flaps were performed to cover the recessions. Postoperative periods of 1, 9, 14, 21, 28 and 35 days were obtained when the animals were killed. A combined solution of Pelikan carbon black and 10% buffered formalin was perfused through the exposed and cannulated external carotid arteries to evaluate revascularization. After killing, blocks, including the operated teeth and the surrounding tissues, were fixed in 10% formalin and then partially decalcified in EDTA. Two blocks per time interval were obtained. One of the blocks was processed for regular histology, and sectioned bucco-lingually. In these sections it was found that the new attachment to the root was mediated by a combination of connective tissue attachment and a long junctional epithelium. The other blocks were cut cross-sectionally at about 1-mm thickness. Sections were selected from three different areas: (a) at the most coronal part of the laterally displaced flap, (b) at the middle of the localized defect and (c) at the bottom of the defect. They were cleared following the Spalteholtz method.(ABSTRACT TRUNCATED AT 250 WORDS)

No abstract

This study evaluated the effects of guided tissue regeneration (GTR) in the treatment of Class II furcation defects in beagle dogs. Gore-Tex periodontal material was used, and the amount of furcation fill and the surface area corresponding to new connective tissue attachment and new bone were evaluated. If present, epithelium was also evaluated. Six female dogs with naturally-occurring periodontitis were given thorough root debridement. Four weeks later mucoperiosteal flaps were raised, involving the mandibular 2nd, 3rd, and 4th premolar and 1st molar teeth. After debridement, notches were placed on the roots at the level of furcal alveolar bone. Gore-Tex material was adapted to the furcation and secured with sutures on two teeth of each quadrant. The flaps were sutured tightly, making sure the margin of the material was covered. Teeth receiving only surgery acted as controls. Gore-Tex material was removed 1 month following surgery. All dogs were sacrificed by exsanguination at 3 months. Mesiodistal sections were evaluated by descriptive histology. Surface area determination of the furcal tissues was carried out using a microscope attached to a computerized digitizer. Approximately 10 serial sections per tooth were evaluated. Mean values for each dog were obtained for experimental and control teeth and analyzed using paired t-tests (N = 6) to see whether different treatments had any effect on the parameters tested. Different degrees of fill were seen with epithelium, new connective tissue, and bone. Statistically, GTR gave significantly better results in the amount of connective tissue and bone fill achieved.

The arterial plan of the head and neck of 64 immature rhesus monkeys (Macacn mulatta) was studied using four techniques -dissection, corrosion preparations, cleared specimens, and angiographs. In general, the arterial plan of this area in the monkey is similar to that of man. However, certain outstanding differences were noted. The origin, course, and distribution of all arteries is described as well as the vascular relations to pertinent structures.As has been mentioned previously (Dyrud, '44; Schwartz and Huelke, '63) the rhesus monkey is useful for many types of medical and dental investigations, yet its detailed gross morphology is virtually unknown. Although certain areas of the monkey have been studied in detailbrachial plexus, facial and masticatory musculature, subclavian, axillary and coronary arteries, orbital vasculature, and other structures (Schwartz and Huelke, '63; Chase and DeGaris, '40; DeGaris and Glidden, '38; Chase, '38; Huber, '25; Weinstein and Hedges, '62; Samuel and Warwick, '55; Eyster, '44; Wagenen and Catchpole, '56; Tokarski, '31; Kennard, '41). other areas have been virtually overlooked or have received but passing attention. The literature on the arterial supply of the primate head has been adequately summarized by Dyrud ('44). Very few investigators, however, have used Macaca mulatta specimens and more importantly in most of the articles only brief descriptions have been presented with many of the pertinent morphological details not having been stated, or overlooked. Additionally, only a few specimens have been used in the majority of these works. It is our purpose to present the arterial plan of the head and neck, especially that of the external carotid arterial system. MATERIALS AND METHODSSixty-four immature rhesus monkeys (Macaca mulatta) were used for this study. All of the animals were embalmed with AM. J. ANAT., 116: 149-170.10% formalin except 17 which were unembalmed. Four different techniques were used for the study of the arterial distribution : ( 1 ) dissections -27 specimens; (2) corrosion preparations -6; (3) cleared specimens -15; ( 4 ) angiographs -16 heads ( 11 unembalmed and 5 embalmed). The arterial system of the specimens used for dissection was injected with vinyl acetate, red latex, or with a red-colored gelation mass. For the dissection of smaller arteries, the smallest of 150 ~1 in diameter, the binocular dissection microscope was used. The corrosion specimens were prepared by injecting the arteries with vinyl acetate followed by maceration of the soft tissue with potassium hydroxide (3-10% ) for 24 to 72 hours. The dye selected for injection of the cleared specimens was Teichmann's paste (Teichmann, '52) colored with cinnabar. These specimens were decalcified in 4% nitric acid and then cleared by the Spalteholtz method. The radiopaque material for the angiographs was the modified Schlessinger's mass (Reiner and Rodriguez, '57), the main components being mercury and barium sulfate.The head and neck was removed from the animal at the level of the cl...