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PubMed1987

Candidacidal factors in murine bronchoalveolar lavage fluid.

Respiratory secretions provide an efficient method for protecting the large surface area of the lower respiratory tract. To determine whether lung secretions contribute to antifungal defenses, we tested bronchoalveolar lavage fluid for fungicidal activity. Candida albicans (blastoconidia) was incubated in unconcentrated cell-free lavage fluid from Swiss Webster mice and then cultured quantitatively to measure residual viability. In control buffer the residual fractions of viable fungi were 1.03 +/- 0.12 at 60 min and 0.84 +/- 0.05 at 120 min, whereas the residual fractions in lavage fluid were 0.64 +/- 0.07 and 0.23 +/- 0.05, respectively (P less than 0.05 by t tests). This activity was trypsin sensitive and heat stable (56 degrees C) and did not require divalent cations. It did not sediment with the surfactant fraction of lung lavage fluid. Unconcentrated lavage fluid reduced the adherence of C. albicans to serum-coated glass tubes to 2.3 +/- 1.5% of that of control Candida suspensions (n = 5, P less than 0.05 by t test). It did not alter Candida ingestion or intracellular processing by alveolar macrophages. Lavage fluid also killed clinical isolates of Candida tropicalis and Torulopsis glabrata but did not kill Candida krusei or Candida parapsilosis. Lavage fluid was concentrated and passed through an acrylamide-agarose gel matrix. The chromatogram indicated that the candidacidal activity eluted in a peak with a molecular weight range of 29,000 to 40,000. After electrophoresis on 15% sodium dodecyl sulfate-polyacrylamide gels, these fractions resolved into three bands. These were transferred to nitrocellulose and then eluted with Triton X-100; this procedure permitted the isolation of a single band of candidacidal activity with a molecular weight of 29,000. In summary, murine lavage fluid contains a heat-stable protein with direct antifungal activity. This soluble factor may contribute to lung defense processes by reducing fungal viability and adherence to tissue surfaces.

Animals↗
PubMed1996

Superficial bone resorption: a negative or positive factor in wound healing?

A review of the literature indicates that one of the major elements of the healing pattern after periodontal surgery is the growth of granulation tissue originating from the periphery of the surgical wound, the periodontal ligament, and the underlying bone. In the past, the periosteum has been given great importance in the process of tissue regeneration; in the current study the authors examined the possible results of removal of the periosteum, which would leave bare bone as the only source of tissue regeneration. The review of a previous study involving perforations to the cortical plate to promote communication between marrow spaces and the receptor bed surface indicated the potential of bone regeneration through the endosteum. The purpose of this article was to stimulate studies devoted to a better understanding of bone potential in periodontal regeneration.

Alveolar Process↗
PubMed2025

Deep inflations maintain surfactant function and alveolar fluid balance in lungs with reduced surfactant protein B levels during mechanical ventilation.

Surfactant protein B (SP-B) is essential for surface tension reducing function of pulmonary surfactant and alveolar unfolding processes during inspiration. SP-B is reduced early in acute lung injury. Hence, we hypothesize that 1) reduced SP-B expression increases susceptibility to ventilation-induced lung injury (VILI), and 2) deep inflations (DI) are protective against VILI. Conditional SP-B knockout mice were randomized into OFF (reduced SP-B) and ON groups (normal SP-B) and subjected to mechanical ventilation at zero end-expiratory pressure. Over 4 h of ventilation, either 4 or 16 DI were administered. Lung mechanics were recorded, and pulmonary structure was quantified by design-based stereology. Inflammatory cells and bulk RNA sequencing were measured in bronchoalveolar lavage (BAL) and tissue, respectively. No differences in inflammatory cells in BAL were detected between ON and OFF groups. During ventilation, alveolar derecruitment-related increase in elastance was most pronounced in OFF-4DI but reversible by DI so that lung mechanics did not worsen. Finally, volumes of the alveolar liquid lining layer and the intracellular surfactant were largest, whereas the surface area of the apical plasma membrane of type II pneumocytes was smallest in OFF-4DI, suggesting impaired surfactant secretion. A higher frequency of DI prevented these abnormalities. Electron microscopy revealed disorganized tight junctions between alveolar epithelial cells in OFF-4DI, which was linked with decreased expression of genes relevant to the apical junctional complex. Reduced SP-B resulted in a progressive increase in surface tension and a disturbed fluid balance without triggering definite VILI. Maintenance of residual surfactant function is highly dependent on DI in conditions of reduced SP-B levels.NEW & NOTEWORTHY Surfactant protein B (SP-B) is critical for efficient surfactant function in the lung. Reduced SP-B levels occur at an early stage of acute lung injury and impair alveolar unfolding. In this study, we demonstrate that mechanical ventilation of lungs with reduced SP-B levels does not trigger ventilation-induced lung injury but results in disbalance of alveolar fluid volume and increase in surface tension due to failure of surfactant maintenance. Deep inflations prevent these ventilation-induced effects.

Animals↗
PubMed1984

Effect of age on the periodontium.

It is generally known that the degree of periodontal breakdown increases with increasing age. The extent to which aging of periodontal tissues plays a part in this respect poses a question which is yet to be answered. Aging proves to be accompanied by a variety of periodontal changes. The periodontal tissues themselves show evidence of aging, there are indications that the composition of the plaque changes, and the reaction of the periodontium to the presence of plaque probably changes as well. There is as yet no sufficient evidence of a physiological apical migration of the epithelial attachment in human subjects. It seems plausible that periodontal breakdown can occur only in the presence of plaque with consequent inflammation of the periodontium, or as a result of trauma. Whether changes in plaque composition with age exert any influence on the course of periodontal breakdown is uncertain: the data available are not yet sufficient to warrant definite conclusions. The same applies to the influence which a changing reaction of the periodontium to the presence of plaque may have on the course of periodontal breakdown. Research findings do suggest that the degree of periodontal breakdown increases with age, that with increasing age inflammation of the periodontium tends to develop more rapidly and that in the process of aging the periodontium shows a slower rate of wound healing. However, these phenomena are overshadowed by the patients' susceptibility to periodontal disease. This implies that (1) the susceptibility to periodontal disease is more significant for the rate of periodontal destruction than the length of time plaque is present (the age effect) and (2) the greater the susceptibility to periodontal disease, the slower the rate of wound healing and the more rapidly inflammation of the periodontium tends to develop.

Adult↗
PubMed1993

An histologic and histomorphometric study of bone reactions to unloaded and loaded non-submerged single implants in monkeys: a pilot study.

The authors present an histologic study of bone peri-implant tissue responses to non-submerged unloaded and early-loaded titanium screw implants in monkeys. Titanium screws were placed in the maxillae of 3 Macacus rhesus monkeys. One crown for each of three implants was placed after 30 days under occlusal contact, while the other three implants were left unloaded (one pair per animal). Fifteen months later, the animals were killed, and block sections were obtained to be processed for histology. Thin ground sections were excised so that histomorphometric analyses could be performed. In all samples examined, a tight contact of new bone to the implant surfaces was observed. Moreover, around the implant necks of the early-loaded screws was observed an histologic pattern of lamellar, cortical bone, thicker than in unloaded implants. Comparison with peri-implant bone of adjacent teeth showed a similarity to the surfaces of loaded peri-implant bone.

Alveolar Process↗
PubMed2005

Smoking affects the self-healing capacity of periodontal tissues. A histological study in the rat.

This study aimed to evaluate in rats the impact of cigarette smoke inhalation (CSI) and nicotine administration (NA) on a periodontal healing model in the absence of a plaque biofilm. Wistar rats (n = 42) were assigned to three groups: Group 1, control (n = 14); Group 2, NA (3 mg kg(-1)) (n = 14); and Group 3, CSI (n = 14). Thirty days after CSI and NA exposure, fenestration defects were created buccally to the distal root of the first mandibular molar. The animals were killed 21 d later and their mandibles were processed for histological examination. The percentage of bone fill and the density of newly formed bone were assessed histometrically. Intergroup analysis demonstrated that compared to the control and NA groups, CSI was associated with a reduced rate of bone repair. No new cementum had been formed along the root surface in any of the three groups. It is concluded that cigarette smoke reduces the self-healing capacity of periodontal tissues.

Alveolar Bone Loss↗
PubMed1984

Deposition and clearance of inhaled particles.

Theoretical models of respiratory tract deposition of inhaled particles are compared to experimental studies of deposition patterns in humans and animals, as governed principally by particle size, density, respiratory rate and flow parameters. Various models of inhaled particle deposition make use of approximations of the respiratory tract to predict fractional deposition caused by fundamental physical processes of particle impaction, sedimentation, and diffusion. These models for both total deposition and regional (nasopharyngeal, tracheobronchial, and pulmonary) deposition are compared with early and recent experimental studies. Reasonable correlation has been obtained between theoretical and experimental studies, but the behavior in the respiratory tract of very fine (less than 0.1 micron) particles requires further investigation. Properties of particle shape, charge and hygroscopicity as well as the degree of respiratory tract pathology also influence deposition patterns; definitive experimental work is needed in these areas. The influence upon deposition patterns of dynamic alterations in inspiratory flow profiles caused by a variety of breathing patterns also requires further study, and the use of differing ventilation techniques with selected inhaled particle sizes holds promise in diagnosis of respiratory tract diseases. Mechanisms of conducting airway and alveolar clearance processes involving the pulmonary macrophage, mucociliary clearance, dissolution, transport to systemic circulation, and translocation via regional lymphatic vessels are discussed.

Animals↗
PubMed1981

The effects on extraction wound healing of a new drug combination introduced for use in the prevention of post-extraction complications. A preliminary report.

Fifteen extraction sockets packed with a new drug combination which includes a local anaesthetic (cincain chloride), a local antiseptic (tri-iodomethane) and two drugs with a potent antifibrinolytic activity (tranexamic acid and propyl-hydroxy-benzoic acid) in an absorbable gelatin sponge (Gelfoam) as a vehicle, were histologically assessed with special reference to the parameters related to wound healing. As a control, the same number of sockets were allowed to heal spontaneously and similarly assessed. Healing of the extraction wounds seemed to follow the normal sequence in both series, and no histological signs suggestive of a delay in the healing process could be found in any of the sockets studied. Also the mast cell count previously considered to be of importance in the connective tissue repair was found to be unaffected by the test substance. These results, together with the previously presented data on the clinical efficacy of the drug combination studied, suggest that a larger clinical study should be carried out to assess its value as a preventive measure against the development of the post-extraction symptoms, including dry socket.

Adolescent↗
PubMed1998

Current perspectives in residual ridge remodeling and its clinical implications: a review.

PURPOSE: This article reviews the current understanding of the biology of tooth extraction wound healing and residual ridge remodeling. METHODS: The review of the biology of tooth extraction wound healing involves a discussion of the different cells populating the tooth extraction wound, the matrix formation, and the control of the repair process in the short-term. Defects in socket matrix formation or cellular activity will lead to stalled healing. The review of residual ridge remodeling describes the long-term result of tooth extraction and formation of residual ridges, in which the quantity of bone tissue continuously decreases. This may suggest that any potential regulatory factors of residual ridge resorption should have an adverse effect either on the increased catabolic activity by osteoclasts or on the decreased anabolic activity by osteoblasts. Both short-term tooth extraction healing and long-term residual ridge remodeling processes are interdependent. Furthermore, any potential genetic and environmental regulatory factors can affect the quality and quantity of bone by altering the gene expression events taking place in bone cells. RESULTS: The intent of this article was to review the current progresses of biologic research on residual ridge remodeling and to relate the changes at molecular, cellular, and tissue levels. The understanding of residual ridge remodeling may provide a sound scientific basis for improved restorative and therapeutic treatments of the edentulous population.

Alveolar Process↗
PubMed2003

Reconstruction of maxillectomy defect by transport distraction osteogenesis.

The study aimed to explore the feasibility of posterior maxillectomy reconstruction by transport distraction in a primate model. In each of 14 male adult rhesus monkeys, posterior partial maxillectomy was performed on one side of maxilla to create a posterior maxillary deflect. Immediately after the maxillectomy, a dentoalveolar segment anterior to the defect was osteotomized as transport segment and a custom-made transport distractor was fixed on the residual maxilla. After a latency period of 5 days, the distractor was activated 1 mm daily to move the transport segment backward to the defect. This process lasted about 2 weeks. The transport segment was allowed to consolidate and the animals were sacrificed at different defined intervals. Transport distraction was successful in six animals. Three other cases were completed with minor wound dehiscence and one had a small oro-antral fistula with subsequent maxillary sinusitis. New bone bridging the distraction gap was confirmed by radiography and histology in the animals completing distraction. Reconstruction of posterior maxillectomy defect is proven feasible by transport distraction osteogenesis.

Alveolar Process↗
PubMedDate not supplied

Corrosion at the marginal gap of implant-supported suprastructures and implant failure.

PURPOSE: Late failure, which occurs after successful osseointegration, is usually attributed to prosthodontic determinants. Corrosion of metallic suprastructures and incorrectly handled materials are often primary causes of late implant failure. In this study, 6 implants whose failure was related to suprastructure metal corrosion and adjacent bone were investigated. MATERIALS AND METHODS: Six implants as well as their suprastructures were analyzed for surface corrosion using light and scanning microscopy. Metal alloys and soldering compounds were analyzed using energy-dispersive x-ray analysis. Bone adhering to the implants was removed and analyzed for metal content using atom absorption spectroscopy. RESULTS: Extensive corrosion lesions and areas of oxidation were detected on all 6 of the implants and inner crown surfaces. Bone tissue collected from 5 of the implants showed higher contents of metal ions in comparison to physiologic baseline values detected in healthy bone. DISCUSSION: In spite of the high gold content of the suprastructure, corrosion occurred. Bonding oxides necessary for the process of fusing porcelain to gold will initiate corrosion. Apparently, once corrosion is initiated it rapidly progresses at the gap crevices, and toxic metal ions are released. These toxic ions diffuse into the peri-implant bone, causing bone structure breakdown and hastening osseodisintegration. CONCLUSION: Biocompatible metals, alloys, and ceramics should be used for implant-supported suprastructures. It is also essential that gaps between the implant and its suprastructure be avoided by cementing the suprastructure or sealing the gap.

Adolescent↗
PubMed1990

Inverted papilloma of the maxillary sinus: an unusual cause of a non-healing extraction socket. Case report.

Although the healing of extraction sites is generally a rapid and uncomplicated process, delayed healing or overt infection of recent extraction sockets may involve a variety of causes and the clinician must be aware pre-operatively of both local and systemic influences. Retarded or non-healing extraction sites always require investigation. This paper looks broadly at the subject of non-healing extraction sites and reports an unusual case involving an inverted papilloma of the maxillary antrum. To the authors' knowledge this is the first reported case of an antral papilloma causing delayed extraction wound healing.

Aged↗
PubMed2006

Enamel matrix derivative versus guided tissue regeneration in the presence of nicotine: a histomorphometric study in dogs.

AIM: The goal of this histometric study was to compare the healing process of dehiscence-type defects treated by enamel matrix derivative (EMD) or guided tissue regeneration (GTR) under the effect of nicotine in the dog model. MATERIALS AND METHODS: Eight mongrel dogs were used. Buccal osseous dehiscences were surgically created on the mesial roots of the mandibular third and fourth pre-molars. The defects were exposed to plaque accumulation for 3 months. After this period, the defects were randomly assigned to one of the treatments: open flap debridement (OFD), EMD or GTR with a resorbable membrane. During 4 months, the dogs received subcutaneous administration of nicotine (2 mg/kg twice a day with a 12 h interval between the applications). After this period, the animals were killed and the blocks were processed. The histometric parameters evaluated included gingival recession, epithelial length, connective tissue adaptation, new cementum and new bone. RESULTS: A superior length of new cementum was observed in the sites treated by EMD in comparison with OFD (p< or =0.05). No statistically significant differences were observed between GTR and the other groups. CONCLUSIONS: In the presence of nicotine, EMD may promote more new cementum formation than OFD while GTR failed to provide a significant difference.

Absorbable Implants↗
PubMed1997

Craniofacial growth after a period of unilateral masticatory function in young rabbits.

Changes in craniofacial growth after a period of unilateral masticatory function were studied in rabbits. 10-day-old animals were divided into 3 groups. In Group I, mandibular and maxillary molars were ground down 2x a week on the right side under general anesthesia until age 50 days, and were thereafter left to grow without grinding. In Group II, the right-side molars were ground until age 40 days on. Between days 40 and 60, grinding was performed on the left side. The animals were thereafter left to grow. Group III consisted of unoperated control animals. All of the animals were fed whole pellets and water ad libitum, and were sacrificed at age 100 days. There were measurable differences in growth after periods of unilateral masticatory function. The mandibular ramus was higher, the condylar processus was larger sagittally, and angles between the anterior or posterior borders of the condylar process and inferior border of mandible were smaller in the treated than in the control animals, and there were differences between right and left sides of the same animal in the maxilla and mandible. The inclination of the articular surface of the glenoid fossa was steeper anteriorly on both sides in the treated than in the controls. It was concluded that growth after a period of unilateral masticatory function in young rabbits does not rectify all of the asymmetric changes in the maxilla, mandible and glenoid fossa resulting from the asymmetric function.

Alveolar Process↗
PubMed1977

[Complications after ambulatory oral surgical interventions, their frequency and importance].

The rate of complications of the healing process observed during or after oral surgical intervention on an outpatient basis amounts to 9.75% of the cases. Most frequently occur tooth-root fractures, alveolitis/osteitis, osteomyelitis, soft-tissue infections, haematomas, postoperative bleedings, antral perforations, sinusitis and perception disorders. The great medical and economic importance of such complications is pointed to on the basis of personal results and relevant data from the literature. An improvement in treatment results can be aimed at by reducing the rate of complications as well as by shortening the duration of treatment. Some relevant suggestions are given.

Alveolar Process↗
PubMed2004

Treatment of interstitial lung disease in children.

The treatment of interstitial lung disease in children depends on the nature of the underlying pathology. In approximately 50% of cases a specific aetiology can be found such as: chronic viral infection, an auto-immune process, sarcoidosis or alveolar proteinosis. In the remainder, the process is idiopathic and the pathological findings are based on the descriptive morphological features seen in the diagnostic lung biopsy. If a specific cause is found then targeted treatment with antivirals, steroids or other immunosuppressive agents is available. Alveolar proteinosis can be treated by bronchial lavage and GM-CSF. Idiopathic cases are treated primarily with intravenous pulsed methylprednisolone or oral prednisolone backed up hydroxychloroquine. Other immunosuppressive agents such as azathioprine, methotrexate or ciclosporin have been used successfully in individual patients. The prognosis is very variable and includes no response to any therapy, partial response with chronic long term morbidity, to virtually complete recovery. The overall mortality rate is 15%. There are no controlled therapeutic trials available because of the rarity of these conditions in childhood. Unlike in adult practice, no correlation has as yet been demonstrated between the initial pattern of chest x-ray change or the degree of pathological change on the lung biopsy and the clinical outcome. The recurrence rate within families is 1 in 8.

Child↗
PubMed2005

Digital imaging analysis with mathematical morphology and fractal dimension for evaluation of periapical lesions following endodontic treatment.

OBJECTIVE: To see if a method for digitizing trabecular pattern of bone could be used to quantitatively evaluate changes in bone pattern following endodontic treatment of teeth with periapical osteolytic lesions. STUDY DESIGN: Periapical radiographs were digitized and further processed with mathematical morphology operations known as skeletonization. The trabecular patterns resulting from this skeletonization process were further analyzed with fractal dimension analysis using box-counting. RESULTS: The periapical area in digitized radiographic images showed fractal behavior. Twenty-five of 27 patients showed increase of the fractal dimension after root canal treatment. Significant changes of the box-counting could be noted 3 months after root canal treatment (P < .05). CONCLUSIONS: Mathematical morphology operation and box-counting might be helpful in early detection of changes of periapical trabecular pattern after root canal treatment.

Adult↗
PubMed1996

Dimension of the periimplant mucosa. Biological width revisited.

The objective of the present study was to determine the dimension of the mucosal-implant attachment at sites with insufficient width of the ridge mucosa. 5 beagle dogs were used. Extractions of all mandibular premolars were performed and 3 months later, 3 fixtures of the Branemark System were installed in each side. Following 3 months of healing, abutment connection was carried out. On the right or left side of the mandible, abutment connection was performed according to the Branemark System manual (control side). On the contralateral side (test side), an incision not extending through the periosteum was made at the crest of the ridge. The soft tissue was dissected and a critical amount of connective tissue on the inside of the flap was excised. The periosteum was subsequently incised, abutment connection performed, and the trimmed flaps sutured. The sutures were removed after 10 days. After a 6-month period of plaque control, the animals were sacrificed, biopsies sampled and processed for light microscopy. The length of the junctional epithelium varied within a rather narrow range; 2.1 mm (control side) and 2.0 mm (test side). The height of the suprabony connective tissue in this model varied between 1.3+/-0.3 mm (test side) and 1.8+/-0.4 mm (control side). At sites where the ridge mucosa prior to abutment connection was made thin (< or = 2 mm), wound healing consistently included bone resorption. This implies that a certain minimum width of the periimplant mucosa may be required, and that bone resorption may take place to allow a stable soft tissue attachment to form.

Alveolar Process↗