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Biomedical subjects

W A Castelli

Publications and source records attributed to W A Castelli.

At least 19 recordsLinked to original sources
PubMed1994

The effect of platelet-derived growth factor on the cellular response of the periodontium: an autoradiographic study on dogs.

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.

Analysis of Variance↗
PubMed1994

Effect of root conditioning on periodontal wound healing with and without guided tissue regeneration: a pilot study. II. Autoradiographic evaluation.

This investigation deals with the proliferation and migration of the progenitor cells during the healing of closed periodontal wounds. Periodontal surgical defects affecting the bone and dentin were created in four mongrel dogs. The defects were treated with topical applications of citric acid, tetracycline, or sterile water with and without the placement of nonresorbable membranes. The dogs were killed at 1, 3, 7, and 21 days after surgery. One hour before they were killed, they were intravenously injected with tritiated thymidine. Tissues were processed and routinely prepared for autoradiographic studies. Labeled cells were counted at the apical, coronal, and central areas of the defects. Results suggested that the citric acid and tetracycline treatments inhibited cellular proliferation at the initial time periods of 1 and 3 days. At 7 and 21 days, differences between citric acid and tetracycline treatments were minimal, and neither showed any advantage over the application of sterile water. The placement of the nonresorbable membrane demonstrated a trend of increased labeling at 21 days for all three treatments.

Acid Etching, Dental↗
PubMed1993

Effect of root conditioning on periodontal microvascular wound healing with and without guided tissue membrane: a pilot study.

The aim of this study was to determine (1) the influence of root conditioners, i.e., citric acid (CA) and tetracycline (TC), on the vascular response of closed periodontal wounds, and (2) the effect of implantation of nonresorbable membranes on the vascularization process. Thirty-two alveolar fenestrations were created in the maxillae of four healthy dogs. The depth of the fenestrations reached the periodontal ligament, cementum, and dentin. Topical application of CA, TC, or sterile water (SW) was done on the exposed dentin. Nonresorbable membranes were then implanted in half of the created defects between the mucoperiosteal flap and the alveolar bone. The vascular response at the experimental sites was determined by histological evaluation and cleared specimens following observation periods of 3, 7, 14, and 21 days post-operatively. Results from this pilot study indicated that: (1) the coronal aspect of the periodontal ligament contributed the most to the initial vascularization of the defect; (2) there was no definitive advantage of the administration of CA or TC on the vascular response at 14 or 21 days; (3) no differences in vascular response were observed between treatment with or without the implantation of nonresorbable membranes; and (4) at 21 days, the vasculature in the defect area had not returned to its presurgical state.

Animals↗
PubMed1993

Effect of root conditioning on periodontal wound healing with and without guided tissue regeneration: a pilot study. 1. Histologic evaluation.

Closed fenestration wounds in four mongrel dogs were used to study the source of fibroblast proliferation and extracellular matrix production during healing; the arrangement and attachment of newly formed collagenous fibers; and the cementogenesis and osteogenesis at healing sites. Fenestration wounds were made through the alveolar bone, periodontal ligament, cementum, and dentin, and citric acid, tetracycline, or sterile water was applied to the dentinal walls for 3 minutes. Nonresorbable membranes were randomly placed over half of the defects. Animals were killed at 1, 3, 7, or 21 days and routine histologic examinations with hematoxylin and eosin staining followed. Results of this pilot study suggest that the periodontal ligament and/or alveolar bone are the main source of fibroblast proliferation and migration as well as extracellular matrix formation at the initial stages of healing, and that at 21 days, citric acid stimulated more cementogenesis than tetracycline or sterile water. Also, while the tetracycline influenced the maximal deposition of alveolar bone, no differences in healing were found between the citric acid, tetracycline, and sterile water with and without the use of membrane barriers.

Acid Etching, Dental↗
PubMed1991

Periodontium response to a root canal condensing device (Endotec).

Two Macaca (fascicularis) monkeys were used to study the effect of two warm endodontic condensation techniques (Endotec and vertical condensation method) on periodontal tissues. The specimens were histologically evaluated at 3 and 32 days after the endodontic treatments were completed. In this study the periodontium was divided into coronal, middle, and apical thirds. Results indicated that there was no heat-related damage to periodontal tissues from either of the two methods employed. However, some Endotec specimens generated small, reactive inflammatory infiltrates that were restricted to the root canal opening or adjacent periodontal membrane. Similarly, some vertical condensation specimens developed periapical inflammatory processes as well, but they were more extensive and comprised the alveolar bone and marrow spaces.

Animals↗
PubMed1990

Furcation defects in dogs treated by guided tissue regeneration (GTR).

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.

Alveolar Process↗
PubMed1988

New attachment achieved by guided tissue regeneration in beagle dogs.

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."

Alveolar Process↗
PubMed1987

Effect of fibronectin on healing of replanted teeth in monkeys: a histologic and autoradiographic study.

The purpose of this study was to evaluate the effect of fibronectin application on healing of replanted teeth. Three rhesus monkeys were used. Maxillary and mandibular incisors and premolars were extracted and replanted. Teeth were extracted with forceps and placed in saline solution. After 5 minutes, each tooth was returned to its socket and immobilized by interproximal acid-etch splints, which were removed after 1 week. Of the forty-eight teeth replanted, twenty-four control teeth were replanted as described. On each of the remaining teeth, the root surface and the inner walls of the socket were bathed with 1 ml of fibronectin in saline solution (400 micrograms/ml) during the 5-minute interval between tooth extraction and its replantation. Replanted teeth and animal killings were scheduled to provide observations 1, 3, 7, 14, 28, and 45 days after replantation. Each monkey received an intravenous injection of tritiated thymidine, 1 microCi/g body weight, 1 hour before it was killed. Tissue specimens were processed for histologic and autoradiographic evaluation following standard procedures. For each of the six points of time, four pairs of contralateral teeth were available for evaluation; four teeth were treated with fibronectin and four without it. The findings of this study indicate that fibronectin use resulted in enhanced healing by early replacement of the fibrin clot, increased connective tissue cell proliferation, reduction of the inflammatory response, and inhibition of both cementum resorption and dentoalveolar ankylosis.

Animals↗
PubMed1987

Effect of citric acid and lyophilized autologous plasma on healing following periodontal flap surgery in monkeys.

The purpose of this histologic, histometric, and autoradiographic study was to examine the effect of citric acid conditioning and lyophilized autologous plasma (LAP) application on healing following periodontal flap surgery. Mucoperiosteal flaps were elevated in six rhesus monkeys using the modified Widman flap procedure. A total of 24 quadrants were treated, each included the first and second premolar and first and second molar teeth. Cementum was removed from the exposed root surfaces, and reference notches were inscribed into the roots at the alveolar bone margin. Two treatment modalities were employed: (1) surgery plus citric acid conditioning, to serve as control and (2) surgery plus citric acid followed by LAP application (400 mg/ml saline). Flaps were returned to their preoperative positions and sutured. Animal sacrifices were scheduled to provide observations 3, 7, 14, 21, 28, and 45 days after surgery. Each monkey received an intravenous injection of tritiated thymidine, 1 microCi/gm of body weight, 1 hour before it was killed. Tissue specimens were processed for evaluation following standard procedures. Histologically, tissue sections were examined for: (1) proliferation and attachment of epithelium, (2) organization and maturation of periodontal fibers, (3) inflammatory cell types, (4) presence or absence of new cementum deposition, and (5) degree of vascularity of the tissues. For histometric evaluation, the radicular notches were used as reference points. The distances examined histometrically were: (1) from the root surface notch to the alveolar bone crest, (2) from the root surface notch to the apical extent of the junctional epithelium, and (3) from the free gingival margin to the apical extent of the junctional epithelium. For autoradiographic evaluation labeled cells were counted in five spatial compartments at 400 X magnification: (1) oral epithelium, (2) crevicular area, (3) supracrestal connective tissue, (4) coronal periodontal membrane, and (5) coronal bone marrow. For each the histometric and autoradiographic evaluation involved a total of 36 tissue sections per quadrant (9 sections per tooth). Tooth and quadrant means were obtained for each monkey. The plasma-treated and control quadrants were compared at each time point by the paired t test. N = 2 monkeys were used for each comparison. Histologic results showed that in teeth that were acid-conditioned after root planing, the epithelium often migrated apically reaching the radicular notch. Those teeth that were conditioned and subsequently treated with LAP demonstrated fiber attachment to the planed root surface and little or no epithelial downgrowth.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

Effect of lyophilized autologous plasma on periodontal healing of replanted teeth.

The purpose of this histologic and autoradiographic study of replanted teeth was to evaluate the beneficial effect, if any, of lyophilized autologous plasma (LAP) application on periodontal healing and to re-examine rates of repair in different areas of the associated periodontium following replantation. Maxillary and mandibular incisors and premolars of three rhesus monkeys were used. Teeth were extracted with forceps and placed in sterile physiologic saline. After 5 minutes each tooth was returned to its socket and immobilized by interproximal acid-etch splints. Splints were removed after 1 week. Of the 48 replants performed, 24 (controls) were replanted as described. Of the 24 experimental teeth, during the 5 minute interval between tooth extraction and replantation, the root surface and the inner socket walls were bathed with 1 ml of the reconstituted LAP-saline solution (800 mg/ml). Replants and animal sacrifice were scheduled to provide observations at 1, 3, 7, 14, 28 and 45 days following replantation. One hour prior to sacrifice, each monkey received an intravenous injection of tritiated thymidine, 1 microCi/gm body weight. Tissue specimens were processed for evaluation following standard procedures. Eight replanted teeth were available for evaluation for each of the six time-points. Four teeth were treated with LAP and four without it. Histologically, tissue sections were examined for epithelial proliferation and attachment, periodontal fibers organization and maturation, inflammatory cell types, presence or absence of cementum resorption and dentoalveolar ankylosis and degree of vascularity of the tissues. For autoradiographic evaluation, the periodontium associated with the replanted tooth was divided into nine spatial cell compartments. In each compartment, labeled tissue cells, epithelial or connective, were counted and recorded. Differences between the control (untreated) replanted teeth and the LAP-treated teeth, at each time-point and within each compartment, were analyzed for significance using the paired t-test. The findings of this study indicate that LAP use enhanced healing by early replacement of the fibrin clot, increased connective tissue cell proliferation, reduction of the inflammatory response and inhibition of root cementum resorption. Periodontal healing and repair occurred more rapidly in the supracrestal or transseptal connective tissue region than within the periodontal membrane space.

Alveolar Process↗
PubMed1985

Histopathologic findings in temporomandibular joints of aged individuals.

Twenty-four TMJs from well preserved 62- to 97-year-old human cadavers, 12 men and 12 women, were used in this study. The TMJs were routinely processed to identify (1) the histologic and histopathologic changes present in the articulations and (2) the components of the joint most frequently affected by these changes. The most significant histopathologic findings were (1) intense fibrocartilaginous proliferations of the condylar head and articular eminence linings, (2) neovascularization or myxomatoid degenerative changes in articular disks, and (3) proliferation of synovial villi, subsynovial tissue, and muscular fibers. The components of the joint most frequently affected were (1) the condylar head (30.4%), (2) the articular disk (21.7%), (3) the synovial lining (13%), (4) the articular eminence (8.6%), and (5) the lining of the articular fossa (4.3%). Five joints were considered to be within normal histologic limits, and one joint was excluded from the study because of metastatic malignancy.

Aged↗
PubMed1985

Healing and revascularization of apical periodontium and dental pulps in apicoectomized and nonapicoectomized tooth replants in monkeys. A study of fully developed teeth.

This report primarily concerns an experimental study of the effect of apicoectomy on the healing and revascularization of the periodontal membrane and dental pulps in tooth replants. Five rhesus monkeys (Macaca mulatta) were subjected to surgical procedures in which twenty incisor teeth were extracted and immediately replanted. Ten of these incisors were subjected to apicoectomy. Healing and revascularization of periapical tissues and dental pulps were evaluated by histologic and India-ink-perfusion techniques. Apicoectomized replants were characterized by (1) loss of dental substance (tooth apex) and creation of large periapical spaces, (2) exposure of dental pulps and production of periapical inflammatory processes with destruction of alveolar bone, and (3) blocking of normal healing because of persistence of chronic periapical inflammatory processes. In contrast, nonapicoectomized replants depicted short-lived primary inflammatory responses and healing processes characterized by variable histologic responses.

Animals↗
PubMed1984

Revascularization following a combined gingival flap-split thickness flap procedure in monkeys.

A combined technique (gingival flap-split thickness flap) was performed in monkeys. The clinical, histological and microvascular aspects of healing were studied, mainly focusing on the gingival flap, since some of the vessels supplying this area were severed during the second phase of the procedure. The animals were perfused with a combined solution of Pelikan carbon black and 10% formalin solution and killed from 1 to 35 days postoperatively. Cleared specimens and regular histology were obtained. It was concluded that: (1) the remaining periosteal vessels and surrounding structures provided enough nutrition for the survival of the gingival flap, (2) the microvascularization was normal at the 14 days postoperative period in both the gingival flap and the apically positioned split areas and (3) the exposed connective tissue remained narrow and exhibited an irregular vascular arrangement throughout the experiment.

Animals↗
PubMed1984

Revascularization following the lateral sliding flap procedure.

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)

Animals↗
PubMed1984

Some histological changes in carpal tunnel contents and their biomechanical implications.

The purpose of this study was to investigate the pathological influence of mechanical stresses that occur inside the carpal tunnel during exertions of the hand. Microscopic changes in fibrous tissue density, in synovial, subsynovial, and adjacent connective tissue density, and in median nerve epineurium density, arteriole wall muscle thickness, and arterial and venule endoproliferation were investigated at 5-mm increments along a 9-cm range of six postmortem wrist specimens. All of these changes increased from normal in the proximal portions of the wrist, -30 to -40 mm from the wrist crease, to maximal values 0- to 20-mm distal to the wrist crease. The changes then decreased toward normal in the distal sections, 20 to 40 mm. The location and character of these changes suggest that repeated exertions with a flexed or extended wrist are an important factor in their etiology. The consistency with which they are found in this and other studies suggests that extreme changes associated with highly repetitive work or additional stress factors are required to produce symptoms in most cases of carpal tunnel syndrome.

Aged↗
PubMed1983

Effects of composite restorations on the periodontal membrane in monkeys.

We evaluated the histopathological response of the periodontal membrane to intentionally-replanted teeth carrying composite (experimental) and silver amalgam (control) restorations in the middle third of each root. The study revealed that the amalgam produced, in the periodontal tissues, an initial localized inflammation that subsided with the subsequent formation of a fibrous capsule. However, the periodontal membrane adjacent to the composite resin restorations demonstrated chronic inflammation. It was concluded that the composite evoked chronic inflammatory responses of the periodontal tissues in monkeys.

Animals↗
PubMed1982

The effects of different splinting times on replantation of teeth in monkeys.

The purpose of the study was to examine histologically the tissue changes affecting the teeth and surrounding structures after using both 7- and 30-day fixation periods on replanted teeth in monkeys. Eight adult male rhesus monkeys were used. The maxillary central and lateral incisors were extracted, treated endodontically, reimplanted, and temporarily immobilized with an interproximal acid-etch splint. The splints were removed at 1 week in half of the teeth and at 30 days in the other half. The monkeys were killed at 7 and 14 days, and at 1, 2, 3, 4, 5, and 6 months postoperatively. The results showed that replanted teeth that were splinted for 7 days recovered uneventfully, whereas the teeth that were splinted for 30 days demonstrated increased areas of root resorption and ankylosis. Thus, it is suggested that after tooth replantation the periodontium will repair rapidly with a shorter time of splinting (7 days). Extended splinting periods (30 days) seem to induce further root resorption and dentoalveolar ankylosis.

Animals↗