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Biomedical subjects

W A Castelli

Publications and source records attributed to W A Castelli.

At least 37 records · Page 2Linked to original sources
PubMed1982

The effect of mechanical stimulation on the keratinization of sulcular epithelium.

This study was designed to evaluate the effect of mechanical stimulation on the keratinization of the sulcular epithelium in four adult Rhesus monkeys. Each animal received a thorough prophylaxis. One week later, each monkey received one of the following modalities of plaque control: (a) daily intravenous tetracycline and rubber cup prophylaxis, (b) daily rubber cup prophylaxis, (c) daily intravenous tetracycline injections; (d) no treatment, as a control. After sacrifice and tissue processing the histologic sections were evaluated for the presence of sulcular keratinization. The keratin width and length were measured, and an Inflammatory Index determined. It was found that all treatment modalities reduced inflammation significantly, when compared to the control. No differences among the three procedures tested were found. Although all permitted keratinization to develop, sulcular keratinization was significantly increased when daily prophylaxes were performed. It was concluded that mechanical stimulation of the sulcular epithelium, seemingly plays a role in promoting its keratinization.

Animals↗
PubMed1981

Vascular response to modified Widman flap surgery in monkeys.

Revascularization of the periodontal tissues was studied after flap surgery. Modified Widman flap procedures were performed in four young Rhesus monkeys. All premolars and molars were involved. Experimental periods covered from 1 day to 90 days. The animals were sacrificed by exsanguination and perfused through the carotid arteries with a combined solution of equal parts of India ink and 10% buffered formalin solution. After fixation and decalcification, part of the blocks were processed to obtain cleared specimens following the Spalteholtz method. The remaining blocks were processed for routine histologic examination. The findings, mainly from the cleared specimens, showed that 1 day after surgery the supraperiosteal vessels in the flap demonstrated an overt hyperemic response. Patency of the vessels in the periodontal membrane and cancellous bone was evident; however, vessels were not depicted in the exposed cortical bone, nor in the clot. Vascular continuity apical to the surgical detachment was observed. In 3 to 4 days vascular proliferation within the organizing clot was observed and anastomosis between the gingiva and cancellous bone or periodontal membrane started to develop. At 7 days anastomoses were evident and vasodilation was present throughout the tissues. At 15 days and thereafter, vascular organization started to decrease, and the only hyperemic foci remaining were associated with areas of delayed bone remodeling, cementum remodeling or persistent marginal inflammation.

Animals↗
PubMed1980

Vascular response of the periodontal membrane after replantation of teeth.

Thirteen replanted maxillary central incisors were studied by means of histologic and cleared sections to evaluate the pattern of revascularization of the periodontal membrane and the modification of its vasculature due to root resorption, dentoalveolar ankylosis, and periapical processes. Early reparative activity was noted in the apical and cervical parts of the replanted membrane where proliferating vessels were intermingling with reparative cells and interrupted collagenous fibers. These areas of the membrane corresponded with those receiving a better vascular supply after replantation. The middle third of the membrane, however, showed a scarcity or absence of reparative cells as a result of delayed revascularization. Root resorption, dentoalveolar ankylosis, or periapical processes changed both the tissue specificity of the replanted membrane and its pattern of vascular supply. Revascularization of the pulps showed vacuolar degeneration due to lack of nutrition.

Alveolar Process↗
PubMed1980

Intraneural connective tissue proliferation of the median nerve in the carpal tunnel.

Segments from the median nerve were removed from the distal fourth of the right forearm and the carpal tunnel area of 23 embalmed human cadavers (12 men, 11 women) to evaluate the proliferation of the intraneural connective tissue and its intrinsic vasculature. The findings suggest that: (1) The proliferative increase of the intraneural connective tissue, primarily, the epineurial layers, is a localized characteristic of the median nerve in the carpal tunnel; (2) this increase in a normal occurrence in males and females; and (3) thicker-walled arterioles and venules are common in the highly dense epineurial tissue; this condition, regarded as an adjunct protective feature, could oppose increased intratunnel pressure and lessen the chances of vascular collapse.

Arterioles↗
PubMed1979

The role of sulcular environment in controlling epithelial keratinization.

The influence of the sulcular environment on the keratinization of the outer surface gingival epithelium was tested in three young adult Rhesus monkeys. A total of 40 mucoperiosteal flaps were raised, and inverted so as to bring the outer surface epithelium in contact with the tooth, and were sutured. The experimental time intervals varied from 1 hour to 60 days. The monkeys received H3 thymidine 1 hour prior to sacrifice. The material was prepared for histologic and radioautographic evaluation. Results indicated that the outer surface epithelium changes its morphology to a nonkeratinized epithelium devoid of deep rete pegs when in close contact with the tooth, resulting in the anatomical characteristics normally seen in sulcular epithelium. It is concluded that the sulcular environment has the capability of controlling the keratinizing potential of the outer surface gingival epithelium. It is further suggested that the constant irritation of bacterial plaque and its products may be responsible for the premature desquamation of the sulcular epithelium which in turn might not allow its full differentiation.

Animals↗
PubMed1978

Gingival response to silk, cotton, and nylon suture materials.

Silk, cotton, and nylon suture materials were implanted in the tunica propria of the gingiva in seven adult rhesus monkeys. The histologie study of twenty-four biopsy specimens indicated that there was neither an increase in the vascular permeability nor a leukocytic margination and migration into the tissues adjacent to the suture materials. However, there was a variable histiocytic reaction, with multinucleated cell formation. This reaction was quite intense with cotton, less intense with silk, and practically absent with nylon. The greater cellular response to cotton was probably due to its more active capacity for modifying the internal biologic medium of the gingvia.

Animals↗
PubMed1978

Cheek mucosa response to silk, cotton, and nylon suture materials.

The cheek mucosa reacted to the implantation of cotton and silk with an aseptic inflammatory exudate which was found 24 hours and 4 days postoperatively. The leukocytic infiltrate was followed by a histiocytic reaction. Which was established at 7 days but which later progressively declined. The comparison of these findings with those previously obtained from gingival tissues revealed that the leukocytic infiltration in the gingiva was minimal or nonexistent. Probably, the difference in the leukocytic reacting capacity of the gingiva and cheek mucosa was due to the different histologic architecture present in both tissues and directly related to the active capacity of the suture materials to modify the internal biologic medium.

Animals↗
PubMed1978

Effect of renovascular hypertension of the morphology of oral blood vessels.

Renovascular hypertension was created in twenty adult male rats to study the effects of systolic hypertension on the morphology of vessels supplying the gingiva, periodontal membrane, pulp tissue, and alveolar bone. Gingival arterioles showed changes consisting mainly of proliferation of the intima and elastic layers, some hyalinization of the wall, and reduction of the lumen. Similar but less frequent changes were observed in the vessels feeding the periodontal membrane; however, pulp tissue and alveolar arterioles were unaltered.

Alveolar Process↗
PubMed1978

Replantation of mature teeth without endodontics in monkeys.

The purpose of this study was to evaluate the histologic response after replantation of mature, developed teeth without endodontic treatment in monkeys. To serve as experimental controls, the other replanted teeth received endodontic treatment. No significant differences were noted in the rate and quality of periodontal tissues healing between the endodontically and the nonendodontically treated teeth in monkeys sacrificed at 5, 7, and 14 days, and at 1, 2, and 3 months after replantation. However, specimens obtained at 4, 6, 9, and 12 months showed that teeth replanted without endodontics developed periapical complications, whereas endodontically treated teeth did not.

Animals↗
PubMed1977

Long-term results after intentional tooth reimplantation in monkeys.

The purpose of this study was to evaluate histologically the long-term response to intentional tooth reimplantation in six rhesus monkeys. The study revealed that cervical and apical root resorption is a universal complication after tooth reimplantation and that arrested areas of resorption will show repair by deposition of cementum. A highly cellular periodontal membrane usually will develop. Periodontal fibers will reattach to reparative bone and cementum but seldom regain functional orientation. Partial or complete ankylosis may result. A further complication is progressive undermining resorption of the ankylosed teeth. Long-term studies are mandatory to evaluate the response to intentional tooth reimplantation.

Alveolar Process↗
PubMed1977

Effects of amalgam restorations on the periodontal membrane in monkeys.

The response of the periodontal membrane to reimplanted teeth carrying amalgam restorations in the middle third of their roots was studied from seven days to six months after grafting. The study revealed that the amalgam restorations produced an initial localized inflammation in the periodontal tissues that subsided subsequently with the formation of a pseudocapsule.

Animals↗
PubMed1975

Healing after tooth reimplantation in monkeys. A radioautographic study.

The purpose of this study was to examine radioautographically the dynamics of tissue changes during healing after reimplantation of maxilliary incisors in adult rhesus monkeys. The period selected for the study was 1 day to 4 months. The study revealed that a new attachment will be restored after tooth reimplantation. Epithelial tissues start to proliferate immediately after reimplantation; this proliferation reaches its peak in 3 days. After 7 days a new junctional epithelium is re-established. Connective tissue proliferation reaches its peak in 7 days and starts mainly from the supracrestal connective tissue and the bone marrow spaces. The interface is undetectable after 7 days, being replaced by young connective tissue which re-establishes the continuity of the periodontal membrane and the supracrestal connective tissue. Orientation and maturation of the fibers are not observed until 4 months after reimplantation. Changes toward root resorption and ankylosis can be seen as early as 14 days after reimplantation.

Animals↗
PubMed1975

The storage of teeth before reimplantation in monkeys. A histologic study.

This study is a histologic comparison of twenty teeth which were extracted, endodontically treated, stored for 7 days at +4 degrees C. and at -10 degrees C., and subsequently reimplanted in ten monkeys. In these monkeys, as controls, ten more teeth were extracted, endodontically treated, and immediately reimplanted. Up to 1 year, 100 per cent success was obtained in those teeth stored at +4 degrees C. before reimplantation, and only 50 per cent success was obtained in those teeth stored at -10 degrees C. before reimplantation.

Animals↗
PubMed1975

Chromosome constitution of cells from human gingiva.

This is a study of cells and chromosomes during serial transfer of tissue cultures, starting from the first mitosis occurring before explantation of normal gingival tissues and continuing until a genotypic variation was attained after explantation. From 16 specimens, 9 could be maintained in vitro for varying lengths of time, 7 for more than 50 weeks. In all cases, at 2 months in cultures and afterward, cells were found to be fibroblast-like cells with heteroploid chromosomal complement. The heteroploidy of the cells was due to extrasomy of chromosomes from all groups. However, chromosomes of the me cells before culturing showed the normal diploid number of 46 chromosomes.

Adult↗