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At least 973 records · Page 54Linked to original sources
PubMed1997

The influence of endodontic treatment upon periodontal wound healing.

The interrelationship between periodontal and endodontic disease has aroused much speculation, confusion, and controversy. Pulpal and periodontal problems are responsible for more than 50% of tooth mortality today. Diagnosis is often difficult since these diseases have been studied primarily as separate entities. The toxic substances of the pulp may initiate periodontal defects through canal ramifications and patent dentinal tubules, thus impairing wound healing in regenerative procedures. Although no studies exist addressing the direct effect of pulpal infection on the outcome of guided tissue regeneration (GTR) procedures, several studies do indicate that pulpal status may play a significant role toward the end results of GTR. This review article discusses the potential influence of endodontic treatment on the long-term outcomes of GTR. Potential pathways between the pulp and periodontal ligament, which may be responsible for the failure of the regeneration of new periodontal attachment apparatus, are explored. Examination and review of the clinical and research findings in the literature relating to perio-endo lesions are made to demonstrate that a negative influence may exist between GTR outcomes and the status of the pulp.

Bacterial Infections↗
PubMed1979

Disinfection of nitrous oxide inhalation equipment.

Cross-infection by contaminated equipment is a potential hazard associated with conscious sedation with nitrous oxide and oxygen . Nosocomial infections have occasionally been linked wih the use of unsterile inhalation devices; microbial contamination of sterile nasal hoods routinely occurs during administration of nitrous oxide; and in vitro experiments indicate that subsequent use of contaminated nasal masks may lead to aspiration of microorganisms. Although the incidence of respiratory disease after such contamination is unknown, it is clear that disinfection of the nitrous oxide apparatus between patients is desirable. A simple cleaning method involving alkaline glutaraldehyde is described that provides adequate disinfection of the rubber goods used in the administration of gas. Superiority of this technique over previously recommended cleaning methods is shown.

Aldehydes↗
PubMed2004

[Necrotizing ulcerative periodontitis. Diagnosis, treatment and follow-up--a case report].

Necrotizing ulcerative gingivitis (NUG) and necrotizing ulcerative Periodontitis (NUP) share many clinical and etiologic characteristics. Both forms are characterized by necrotic gingival tissues, bleeding and pain. Malodor and malaise may be also present. NUG is an infection limited to the gingiva whereas NUP also involves the attachment apparatus. Predisposing factors may include immune dysfunction, poor oral hygiene, cigarette smoking and emotional stress. NUG and NUP might possibly be different stages of the same infection. This case report shows the successful treatment of a patient suffering from NUP.

Adult↗
PubMed1989

[Electron microscopic study of periodontal tissues in the pressure side by intermittent forces].

The intermittent forces (10g and 30g) were applied to the upper right first molars of mature Wistar rats to move them lingually for 1, 5 and 9 days with wire springs. The periodontal tissues in the pressure side were investigated light/electron-microscopically and cytochemically (localization of acid phosphatase activity). The periodontal tissues in the pressure side divided into the following three areas were observed. The area I: The area of hyalinized tissues. The area II: The area situated within 100 microns from the end of hyalinized tissues. The area III: The area situated within 100 microns from the border of area II. The following results were obtained. I Tooth movement Experimental teeth applied with 30 g were moved much more than those applied with 10g. II Light microscopic findings 1) The narrowness of the periodontal space in the area I was not observed remarkably on 1 and 5 day experiment of 10g and 1 day experiment of 30g, though hyalinized tissues had appeared in them. 2) Semi-hyalinized tissues observed in some parts of area II degenerated into hyalinized tissues during the experimental periods. 3) Direct resorption of alveolar bone by osteoclasts was seen initially in the area III on 5 day experiment of 10g and 1 day experiment of 30g. III Electron microscopic findings 1) The hyalinized tissues (area I) and semi-hyalinized tissues (some parts of area II) were characterized to contain only a few necrotic cells and cell debris. The localization of Acpase activity could not be seen in these cells and cell debris. 2) Fibroblasts in the area II and III showed various appearances; autophagy, heterophagy of collagen fibrils, fusion with other fibroblasts and cell degeneration. And the localization of Acpase-activity was observed remarkably in lysosomes, secondary lysosomes and Golgi apparatus. A few macrophages were observed in the area II and III, but the other inflammatory cells and foreign body giant cells could not be seen. 3) On the other hand, active and inactive osteoclasts were seen on the bone surface in both area II and area III.

Animals↗
PubMed1979

[Reproducibility of the jaw relation record].

The jaw relations in edentulous patients were determined with the use of the gotic arch and wax bite blocks. To compare the different methods interchangeable tracing devices and wax registrations were used. This apparatus was alternatingly used by various investigators, but with the same base plate. A quick and reliable survey of the results was possible with this experimental procedure. Our study confirmed the superior reproducibility of the graphic method with centrally supported needle.

Dental Impression Technique↗
PubMed1992

Macroscopic sectioning of undecalcified tissues.

An inexpensive laboratory apparatus designed to section undecalcified teeth and bone has been constructed. It consists of an electric motor with a mandrel bearing a carborundum sectioning disk centered within a Plexiglas enclosure. A coolant flows from a reservoir positioned in the upper portion of the Plexiglas enclosure to prevent desiccation or burning of the tissues. Undecalcified tissue can be cut into a series of thin, 0.5-1 mm slices to facilitate studies of pulpal enzymes, tooth morphology and design of dental cavity preparations.

Humans↗
PubMed1985

Diagnostic problems in oral pathology.

Diagnostic problems within the oral cavity may be associated with lesions of the odontogenic apparatus, salivary glands, bone, mucosa, and connective tissue. Some lesions are unique to the oral cavity, others have a systemic distribution. Several unique and controversial lesions have been selected for discussion, including (1) necrotizing sialometaplasia, a benign salivary gland disease easily mistaken for malignancy; (2) verrucous lesions including verrucous carcinoma, verrucous hyperplasia, and papillary carcinoma; (3) spindle-cell carcinoma, which is often confused with sarcoma; (4) named and unnamed embryonic rests, which may resemble metastatic carcinomas; (5) dental pulp mistaken for odontogenic myxoma; and (6) granular cell tumor with associated pseudoepitheliomatous hyperplasia.

Carcinoma, Papillary↗
PubMed1993

Effects of dentin permeability and hydration on the bond strengths of dentin bonding systems.

This in vitro study evaluated the shear bond strengths of five adhesive systems bonded to dentin with and without simulated physiologic hydrostatic pressure. To simulate pulpal pressure, bonding procedures were done on extracted teeth connected to a hydration apparatus. Bond strengths were significantly less for each adhesive system under simulated physiologic conditions. Amalgambond had significantly higher bond strengths than Clearfil Photo Bond, Gluma, Scotchbond 2, or Tenure, either with or without simulated pulpal pressure.

Analysis of Variance↗
PubMed1995

Physical dimensions, torsional performance, bending properties, and metallurgical characteristics of rotary endodontic instruments. VI. Canal Master drills.

A laboratory study was performed on machine-driven Canal Master drills to determine their physical dimensions, torsional performance, bending properties, and metallurgical characteristics in fracture. Physical dimensions were determined for each of the available sizes (#50 to #100) of Canal Master drills from the manufacturer that distributes these instruments in the United States. Samples were also tested in clockwise torsion using a Maillefer memocouple. Bending properties of cantilever specimens were measured with a Tinius Olsen stiffness tester. Bending fatigue testing was performed on a unique laboratory apparatus. Scanning electron microscope examination confirmed visual observations that the stainless steel Canal Master drills exhibited ductile torsional fracture. This study is part of a continuing investigation to establish standards for all machine-driven rotary endodontic instruments.

Dental High-Speed Equipment↗
PubMed1979

Axial stiffness of retention pins in human dentin.

Axial deflections of pins, anchored in specimens of human dentin by five different procedures, were measured by a specially constructed apparatus to an accuracy of 0.1 mu. Axial stiffness values calculated from these measurements were found to be significantly different for different methods of anchorage. Cemented pins displayed the lowest axial stiffness when compared with friction-locked and self-threading pins.

Acrylic Resins↗
PubMed2004

Retention characteristics of attachment systems for implant overdentures.

PURPOSE: The aim of this study was to compare the retention characteristics of various overdenture attachment systems commonly used to retain overdentures to dental implants. MATERIALS AND METHODS: An edentulous mandibular model was constructed incorporating 2 parallel 4.0 mm x 13 mm Branemark implants placed in the canine regions. Attachments were embedded in a metal-reinforced experimental overdenture designed to be dislodged from the model by a universal testing machine. Tensile dislodging force was applied to the overdenture at a cross-head speed of 50 mm/min. Five overdentures were constructed for each of the attachment systems. The attachments evaluated were the Hader bar & metal clip, Locator LR pink, Locator LR white, Spheroflex ball, Shiner magnet, Maxi magnet, Magnedisc magnet, ERA white, and ERA gray. Each apparatus was tested with 5 specimens per attachment system. Peak load-to-dislodgement was measured. Analysis of variance and Scheffe multiple comparison tests were applied to the data with alpha< or = 0.05 level of significance. RESULTS: Peak load-to-dislodgement for all attachment systems ranged from 3.68 +/- 1.32 N to 35.24 +/- 1.99 N. Strain-at-dislodgement, calculated from stress-strain curves, ranged from 0.78 +/- 0.20% to 2.78 +/- 0.5%. The ERA gray attachment demonstrated the greatest retention, with a peak load-to-dislodgement of 35.24 +/- 1.99 N, and a relatively low strain-at-dislodgement of 1.64 +/- 0.09%. Less retention was recorded for the Locator LR white, Spheroflex ball, Hader bar & metal clip, and ERA white systems. The Locator LR pink attachment demonstrated still less retention with a load-to-dislodgement of 12.33 +/- 1.28 N. Significantly high strain-at-dislodgement was recorded for the Hader bar & metal clip and Locator nylon attachment systems. The lowest dislodging loads and strains were recorded for the Shiner magnet, Maxi magnet, and Magnedisc magnet attachments. CONCLUSIONS: Results suggest that the attachment systems evaluated may be grouped into high (ERA gray), medium (Locator LR white, Spheroflex ball, Hader bar & metal clip, ERA white), low (Locator LR pink), and very low (Shiner magnet, Maxi magnet, Magnedisc magnet) retention characteristics.

Analysis of Variance↗
PubMedDate not supplied

[Medical equipment at the Leipzig Fall Fair of 1977].

An analysis of the most interesting exponents of the Leipzig autumn fair of 1977 served as a groundwork for an attempt to outline the major orientation and trends in the development of the biomedical engineering. The advantages of the functional units method of designing are taken notice of on an example of some groups of devices manufactured both in the countries members of the Council for Economic Mutual Assistance and in western countries. Emphasis is placed on the good prospects offered by medical devices for ultrasonic location of the heart with the type M scanning, of the X-ray units intended for solving concrete diagnostic objectives within a narrow branch of medicine (apparatus for mammography, for use in urology, etc). Particular attention is paid to the medical equipment utilizing the elements of computer technique, in the form of built-in units and also in that of complex setups in which small computers ensure the most effective realization of the diagnosis and treatment.

Dental Equipment↗
PubMed1983

A morphological, tracer and cytochemical study of the role of the papillary layer of the rat-incisor enamel organ during enamel maturation.

Thin-section, freeze-fracture, tracer and cytochemical methods showed that papillary cells were characterized by the presence of numerous mitochondria and microvilli. The cytoplasms contained Golgi apparatus, multivesicular bodies (MVB), tubular structures and coated vesicles. In freeze-fracture replicas, some tubular structures and vesicles were continuous with the cell surfaces. Intravenously-injected horseradish peroxidase (HRP) was rapidly incorporated into the papillary cells via coated vesicles and tubular structures. Horseradish peroxidase-labelled coated vesicles and tubular structures then fused with endocytic vacuoles and MVB. These endocytic vacuoles and MVB showed HRP-labelling of various degrees. Acid-phosphatase activity was demonstrated in the Golgi apparatus, endocytic vacuoles and MVB of papillary cells. Enzymic activity sometimes took place in tubular structures but never occurred in coated vesicles. These results indicate that absorptive and digestive activities of papillary cells are closely related to loss of organic materials from the enamel matrix during enamel maturation.

Acid Phosphatase↗
PubMed1993

Inhibition of prostanoid synthesis depresses alveolar bone resorption but enhances root resorption in the rat.

Tooth drift requires the deformation of the root socket and the adjustment of the other components of the attachment apparatus, namely, the periodontal ligament (PDL) and the cementum. Indomethacin (7.5 mg/kg/d), an inhibitor of prostanoid synthesis, provoked in rats a depression in the bone resorption effecting the deformation of the socket (Lasfargues and Saffar, Anat. Rec., 234:310-316, 1992). In the present paper we examined the consequence of this treatment both on the PDL and the root surface. After 3 days of treatment, when osteoclastic resorption was not yet disturbed, the root had been markedly resorbed (P < 0.05) opposite the resorbing bone surface; at that time the PDL width remained in the normal range. After 7 days, i.e., when the bone resorption was depressed, the PDL was widened as the result of the ongoing root resorption. Despite the extensive root resorption, the anchorage of the PDL fibers appeared to remain effective, suggesting that it was rapidly restored. On day 14 at the time of the bone resorption recovery, cementum was deposited in the root resorption lacunae and the PDL width had returned to its control value. As early as day 3 the daily rate of dentine formation increased in the pulp area subjacent to the root resorption lacunae (P < 0.01). These data demonstrate that i) the responses of the different components of the periodontal apparatus are coordinated to allow for the maintainance of the PDL width so that when bone resorption is disturbed, root resorption compensates for it, and ii) the odontoclasts can differentiate and resorb under prostanoid inhibition whilst osteoclastic resorption of the bone socket is inhibited.

Adaptation, Physiological↗
PubMed1977

[The occlusal bite splint and its effect on the centric relation of the maximal opening and closing movement in cases of temporomandibular joint syndrome].

Nine patients presenting temporo-mandibular joint pain-dysfunction syndrome were treated with occlusal bite splints made of acrylic resin, which eliminated premature contacts and occlusal interferences. Results were obtained with an extra-oral apparatus, of personal conception, which allowed to amplify and register maximum opening and lateral deviation in the frontal plane. The study has shown that this treatment brings: - an elimination of pain and muscle spasms - an increase in maximum opening - a decrease in lateral deviation - a marked but partial decrease in articular noises.

Dental Occlusion, Centric↗
PubMed1988

The effect of altering angulation in T loops on the moment to force ratio.

The effect of changing angulation of a T loop on the force systems developed at the alpha and beta ends was determined. Standard 0.017'' X 0.25'' tMA T loops were used. The force systems were determined using testing apparatus developed in this laboratory. The relationship between moment to force ratio and activation is linear at higher activations (3mm-7mm), and becomes non-linear at lower activations (less than 3mm). The relationship between moment to force ratio and spring angulation is also linear. The clinical application of these findings is discussed.

Dental Stress Analysis↗
PubMed1977

The early mineralization of enamel. Fine structural observations on the cellular localization of calcium with the potassium pyroantimonate technique.

The potassium pyronatimonate technique was used to study the cellular distribution of calcium during the early mineralization of enamel in rat molar tooth germs at the electron microscope level. Differing patterns of calcium distribution were observed in the ameloblast seemingly associated with the appearance of Tomes' process. In the early secretory ameloblast calcium pyroantimonate deposits were observed within the Golgi apparatus, within coated vesicles, within mitochondria and associated with the inner aspect of the cell membrane. However, with the development of Tomes' process the ameloblast no longer demonstrated these discrete deposits of calcium pyroantimonate. Instead they showed a diffuse cytoplasmic staining pattern with no preference for any particular organelle.

Ameloblasts↗