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PubMed1983

A new technique for exposure of osteocytes and transalveolar fibres of the interdental septum in the mouse for scanning electron microscopy.

The technique selectively removes the fibrous component of the interdental septum. Mandibles were fixed, demineralized and incubated at 37 degrees C in 0.1 per cent bacterial collagenase. Samples were post-fixed in 2 per cent buffered osmium tetroxide for 24 h prior to dehydration in ascending grades of acetones. While in pure acetone, tissue was ultrasonicated at 80 kHz for 5 min and conventionally processed for scanning electron microscopy. Ultrasonication of tissue without prior collagenase digestion did not expose transalveolar fibres in their entirety. After 6 h exposure to collagenase followed by ultrasonication, bone matrix and osteocytes were removed exposing transalveolar fibres which passed through the interdental septum without interruption, becoming continuous with the periodontium of the adjacent tooth.

Alveolar Process↗

PubMed2000

Marginal bone level around implants assessed in digital and film radiographs: in vivo study in the dog.

BACKGROUND: One of the objectives of postoperative radiographic examinations of implants is to evaluate the marginal bone height and its changes over time. PURPOSE: The purpose of this study was to assess the influence of digital image processing on measurements of the marginal bone level around implants. MATERIAL AND METHODS: Implants in beagle dogs, used to study the development of peri-implantitis and subsequent healing following treatment, were monitored with conventional radiography and a digital image plate system. Five observers measured the distance between a reference point and the bone level. Measurements in conventional radiographs were made with the use of an x-ray viewer (2x) and a magnifying lens (7x). For the digital images, the system's built-in measuring function was used together with five image processing techniques: edge enhancement (matrixes set on 5 and 25), inverted grey scale, single color highlight, and color intensity mapping together with the brightness and contrast control. From the time of maximum breakdown and the end of the experiment, histologic values were available. RESULTS: Differences between techniques and observers increased toward the end of the healing period. Measurements made at maximum breakdown did not differ significantly from the histologic value. Measurements made after healing all methods, except that using edge enhancement and a 25 x 25 kernel, differed significantly from the histologic value by underestimating the bone level. CONCLUSIONS: Measurements of bone level around implants from digital radiographs are as accurate and precise as those from film images. In particular cases, the use of specific image processing algorithms may improve both accuracy and precision. After healing, the histologic specimens showed an incomplete bone fill in the crater with a remaining thin layer of connective tissue in contact with the fixture, and in such situations, the morphology of the bone will give a more complicated diagnostic task.

Algorithms↗

PubMed1983

Healing responses of human intraosseous lesions following the use of debridement, grafting and citric acid root treatment. II. Clinical and histologic observations: one year postsurgery.

This report details histologic healing responses at intrabony sites within two patients about 1 year after surgery. Treatment consisted of open flat debridement of the lesions. At specific sites, augmenting procedures such as autogenous grafts, allografts, synthetic grafts and citric acid root treatment were utilized. In addition, notches were made through calculus prior to root planing at specific root surfaces. These notches were placed at varying distances from the base of the lesion. Patients were followed postsurgically with frequent maintenance visits. Block sections were removed at the end of the experimental period. Clinical reduction in pocket depth was noted at all treated sites. This reduction consisted of limited pocket closure, marginal gingival recession and repocketing. Histologically, all specimens showed evidence of repair. The most mature repair appeared at sites treated with debridement and autogenous grafts. "Regeneration" of lost periodontal attachment was demonstrated by evidence of cementogenesis, osteogenesis and the presence of functionally oriented ligaments. However, the coronal regeneration appeared spatially limited. Allografts showed a similar, but less mature healing response. Synthetic graft material acted essentially as a "filler" within the defect. Citric acid root treatment did not demonstrate clear evidence of augmentation of the repair process. Of particular note in these human specimens was further histologic demonstration that "regeneration" potential apparently can only take place in close proximity to histologically viable periodontal ligament cells which may act as "donor sites" for coronal "regeneration" of lost periodontal attachment. This histologic response was observed regardless of treatment modalities used.

Adult↗

PubMed1993

Experimental studies of the implant-tissue interface.

This comparative study analyzed the epithelial, gingival connective tissue, and osseous tissue interface with clinically and radiographically integrated endosteal dental implants. Undecalcified interfacial tissues were sectioned for both routine transmission electron microscopy (TEM) and for High Voltage Electron Microscopy (HVEM). A protective perimucosal biological seal was formed by regenerating soft tissues (epithelium and connective tissue). Inferior to this protective soft-tissue attachment seal, the apical support complex was shown to vary in morphology. Mineralized bone was closely apposed to significant regions of the implants, separated only by an electron-dense deposit of approximately 20 nm. Osteoblasts were observed adjacent to the implant, as were osteocytes within the underlying supporting bone. Osteoblasts were observed associated with a connective tissue stroma adjacent to the existent mineralized bone. Osteocyte cellular processes extended toward adjacent osteocytes, toward vascular elements, and directly to the implant surface. These observations demonstrate the healthy interface of mineralized tissues with both root-form and blade implants. Mineralization patterns of the bone supporting the implants appeared consistent with normal mandibular maturation patterns.

Alveolar Process↗

PubMed1991

[Isotopy and multicorticality: two fundamental principles].

Starting out from Oral Implantology pioneers, the Author comes down to the present situation, in an effort to show which values should be considered as the true ones. "Nothing new under the skies" is the Author's comment, when he examines all the techniques and materials presented as "new" for commercial purposes, whereas they are not new at all. To prove his statements he goes back to the work of some implantology pioneers, such as Formiggini, Perron Andrès, Cherchève, Strock, Pasqualini, Muratori, Tramonte, Linkow and others. In going over their most remarkable techniques, he maintains that what is being proposed nowadays as brand new was actually done long ago. Only names are now different: the process now called fibrous osseointegration used to be named osteofibrosis, and what is now called osseointegration was known as complete ossification. In order to remove the great confusion now prevailing in the dozens of implant systems, as well as in implant philosophy itself, the Author maintains that good implantologists should follow two fundamental principles: 1) implants should be built in a great variety of sizes, in order to take full advantage of cortical bones. They should be multicortical, generally quadricortical, since they should rest on the sinus floor cortical bone, on the alveolar ridge, the palatal and the buccal cortical bones (this is true for the elements implanted in the upper arch and in the front-mesial arch).(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Process↗

PubMed2004

Detection of dentin sialoprotein in rat periodontium.

Cloning and sequencing of the cDNA indicates that dentin sialophosphoprotein (DSPP) is a precursor of both dentin sialoprotein (DSP) and dentin phosphoprotein (DPP). Dentin sialophosphoprotein must be proteolytically processed to form these two extracellular matrix (ECM) proteins. Numerous studies led us to conclude that DSP (and DSPP) are exclusively expressed by odontoblasts and preameloblasts. However, recent observations suggest a wider distribution. To test this hypothesis, we conducted systematic studies on rat first molar during root formation with immunohistochemical techniques using specific anti-DSP polyclonal and monoclonal antibodies. We also performed in situ hybridization, using high-stringency RNA probes to detect DSP transcripts. Immunohistochemical studies demonstrated that DSP is not only localized in odontoblasts, dentin ECM and preameloblasts, but also in alveolar bone, cellular cementum, osteocytes, cementocytes, and their matrices. The results of in situ hybridization were consistent with those from immunohistochemistry, showing the expression of DSP transcripts in osteoblasts of alveolar bone, fibroblasts in periodontal ligament and cementoblasts in cellular cementum. Together, these observations suggest that DSP is involved in formation of the periodontium as well as tooth structures.

Alveolar Process↗

PubMed2005

[Morphologic analysis of reparative osteogenesis in cases of immediate dental implantation in experiments on rabbits].

In experiments on 24 rabbits it was found out that in the period from 2 to 6 weeks after the tooth had been extracted regenerative tissue in alveola went through the series of successive stages of maturation, beginning from indifferent areolar tissue and finishing with porous fibroreticular bone. Similar process of reparative osteogenesis took place around the implant after immediate dental implantation and young bone tissue had been formed during 2 months. In the area of artificial osseous defect under the membrane of allogenic lyophilic dura mater the adequate osteointegration of implants was observed, while without this membrane transgression of regeneration of the jaw-bone took place.

Alveolar Process↗

PubMed2005

[Pulmonary alveolar microlithiasis].

Pulmonary alveolar microlithiasis (PAM) is a rare, chronic lung disease characterized by extensive intra alveolar calcium and phosphate deposition throughout both lung parenchyma. Etiology and pathogenesis of PAM is not known. There are some hypothesis for etiology and pathogenesis of PAM but none of them are satisfactory. The incidence of PAM is high in countries such as Turkey, Italy and USA. There is a surprising discordancy between radiological appearance and clinical presentation. Chest X-ray appearance of PAM is almost pathognomonic. Patients with PAM may have all findings of interstitial lung disease in varying degrees as well as micro-nodules on their HRCTs. Patients with PAM usually asymptomatic until the underlying process affects alveolar gas exchange however patients may ultimately develop hypoxemia and cor pulmonale. A definitive therapy for PAM did not exist. Patients with advanced lung disease may benefit from lung transplantation.

Calcinosis↗

PubMed1985

Healing after root reimplantation in the monkey.

The aim of the present investigation was to evaluate the regenerative potential of the periodontal tissues following tooth reimplantation using a model which excluded the dentogingival epithelium from the process of healing. Maxillary and mandibular incisors, premolars and molars of 5 monkeys were used. Following root filling of all experimental teeth, the teeth were divided into 3 experimental groups. In 1 group, the teeth were extracted following the elevation of full thickness flaps. The crowns were separated from the roots at the level of the buccal cemento-enamel junction and the roots immediately reimplanted into their sockets. The flaps were replaced and sutured to accomplish complete coverage of the roots. In a 2nd group, the teeth were subjected to the same experimental procedure, but in addition, the buccal alveolar bone was removed to about half its original height prior to root reimplantation. The teeth of the 3rd group were subjected to identical experimental procedures as for group II with the addition that the buccal root surfaces were planed to the level of the surgically created bone crest. The animals were sacrificed after 6 months of healing. The jaws were removed and histological specimens prepared for microscopic examination. The results showed that a complete fibrous re-attachment formed onto roots on which the original periodontal ligament tissue was preserved. This occurred irrespective of whether the roots were reimplanted into sockets with normal (group I) or reduced (group II) bone height. When the original periodontal ligament tissue was removed by root planing before reimplantation (group III), healing resulted in a significant amount of new connective tissue attachment. However, coronal to the newly formed fibrous attachment, the root surface frequently showed signs of resorption and particularly so in those roots which remained covered by the soft tissue during the entire course of healing. In the majority of the roots which perforated the covering soft tissue during the early phase of healing, the dentogingival epithelium had migrated apically into contact with the coronally generated fibrous attachment. In these cases, root resorption was never discernible. New bone formation occurred to a variable extent in the roots of groups II-III. No relationship was found, however, between the amount of connective tissue reattachment or new attachment and newly formed alveolar bone, which in turn indicates that bone tissue regrowth and periodontal ligament regeneration are unrelated phenomena.

Alveolar Process↗

PubMed2004

Accuracy of supported root ratio estimation from projected length and area using digital radiographs.

BACKGROUND: The purpose of this study was to evaluate the accuracy of supported single-root surface ratio estimated from the length and projected area of the tooth, using digital dental radiographs. METHODS: Eight extracted, single-root teeth were three-dimensionally digitized using a contact technique for surface area measurement. The data were then processed using engineering application software and length, projection area, and true surface area of the root at a designated length were obtained. Based on these three measurements, the accuracy of the supported surface area ratio measurement at different lengths of the root was evaluated. RESULTS: The largest mean errors from linear and area estimation were 9.58% and -1.16%, respectively. The 95% confidence intervals were all positive, indicating that linear measurements overestimated supported ratio. T tests showed that linear estimations resulted in significant differences in all eight teeth and area estimations in five teeth. When analyzing the supported ratio of the alveolar bone receding from the cemento-enamel junction (CEJ) toward the apex of the root at each mm, linear estimation showed significant differences down to 8 mm, while area estimation showed significant differences only up to 2 mm. CONCLUSIONS: The results of this study indicate that a reliable estimate of the ratio of root surface area supported by alveolar bone cannot be determined from linear or area data. However, when the marginal bone destruction exceeds 2 mm from the CEJ, area estimation does not show a significant difference in the supported region. As demonstrated in this study, root surface ratio estimation function could be an advantage of digital dental x-ray systems in which projected root area is readily observed.

Alveolar Process↗

PubMed1980

Plasma cells and their immunoglobulins in the normal and delayed healing of the extraction wound in man.

Eight volunteer patients underwent simultaneous extraction of two diseased teeth, the sockets of which were histologically and immunohistochemically evaluated one and two weeks later with special reference to the plasma cells and their intracytoplasmic immunoglobulins, respectively. One of the sockets was allowed to heal spontaneously, the other was packed with Alvogyl (Septodont, 1974) known to induce delayed healing of extraction wounds. A small and constant number of plasma cells was found to be present in the wounds, and this number was not affected by the Alvogyl packing or the stage of wound healing process. Immunoglobulins IgA, IgG and IgM were demonstrated in the plasma cells in proportions characteristic to the plasma cells of oral mucous membranes in general, thus supporting the concept that plasma cell activity in the extraction wound is evoked also by the continuous presentation of the diversity of oral antigens, and not an essential component of the wound healing per se.

Adult↗

PubMed1996

Room for improvement? The accuracy of dental practitioners who diagnose bony pathoses with radiographs.

OBJECTIVES: The impact of any effort aimed at improving diagnostic accuracy by improving clinical decision making in diagnostic radiology will be limited by the ability of the clinician to correctly recognize the presence of abnormalities on radiographs. We carried out a study designed to examine whether dentists are able to correctly identify various kinds of periapical bone lesions visible on intraoral radiographs and diagnose their pathologic nature. STUDY DESIGN: General dental practitioners (n = 98) assessed 32 radiographs that showed either normal bone (10) or one abnormality (22) in the periapical bone. The "gold standard" for pathosis was histopathologic analysis. The dentists were asked to judge for the presence of an abnormality and to decide whether an active pathologic process was present. RESULTS: On average dentists identified 81% of all visible abnormalities correctly. Subsequently, they diagnosed 59% of all the pathologic cases correctly. Dentists, however, incorrectly identified 55% lesions on radiographs when experts had stated that no abnormality was visible. CONCLUSION: There is room for improvement of diagnostic accuracy of bony pathology.

Alveolar Process↗

PubMed1995

Regulation of annexin I by proteolysis in rat alveolar epithelial type II cells.

Limited proteolysis of annexin I occurs endogenously in intact rat lung alveolar epithelial type II cells as revealed by immunoblot analysis. Proteolysis increases in the presence of phorbol 12-myristate 13-acetate (PMA), terbutaline, or ATP, agents that enhance secretion of lung surfactant from type II cells. Calpain, a calcium-dependent neutral protease, was activated in stimulated type II cells and cleaved purified annexin I at the N-terminus minus 26 amino acids. Liposome aggregation activity of truncated annexin I showed ten-fold increase in calcium sensitivity compared to the native form. The results suggest that proteolytic modification may be a regulatory mechanism for annexin I to mediate the secretory processes of alveolar type II cells at physiological calcium concentrations.

Adenosine Triphosphate↗

PubMed1997

Dynamic biologic transformation of the periodontium: a clinical report.

The technology of dynamic biologic transformation of the periodontium differs from orthodontic therapy in that the primary goal of dynamic biologic transformation of the periodontium is to reshape an abnormal periodontium. The goal of orthodontic treatment usually is the straightening of teeth in the orofacial complex. The new term dynamic biologic transformation of the periodontium has been coined to differentiate between a change in the periodontium that is secondary to straightening teeth through usual orthodontic methods to one that the primary goal is the rearrangement of the periodontium in which the tooth is merely used as a handle to pull the periodontium into the desired shape and location. The tooth or teeth that are moved in this process are often reshaped or put into abnormal positions to accomplish this goal. A review of the literature revealed that these changes in the periodontium can be used in various manners that will lessen surgical morbidity and maximize esthetics in conjunction with restorative and periodontal care. Combinations of dynamic biologic transformation of the periodontium and surgery were shown through clinical reports to illustrate this principle.

Adult↗

PubMed1997

Tooth intrusion in implant-assisted prostheses.

STATEMENT OF PROBLEM: Numerous reports and surveys have been published on natural tooth abutment intrusion with implant-connected fixed partial dentures. The consensus of these publications was that the cause of intrusion was multifactorial, with causative factors such as disuse atrophy, debris impaction, impaired rebound memory, and mechanical binding. It was also believed that the process was irreversible. PURPOSE: In this article, the limitations with these theories are discussed, and two patient reports of tooth intrusion reversal are reviewed. A review of the current literature is discussed, as well as the current theory of tooth movement in response to dynamic mechanical stimulus, a brief discussion of current experimental procedures and results, and the current recommendations for reversal of intrusion.

Alveolar Process↗

PubMed1999

The sliding sulcus procedure: simultaneous repair of unilateral clefts of the lip and primary palate--a new technique.

During embryogenesis the clefting event unleashes a series of processes that act in concert to deform the soft tissue envelope into a "dysfunctional matrix" within which bone and cartilage subsequently form. Much of secondary cleft deformity results from failure to solve this pathologic soft tissue-bone equation at the primary repair. The sliding sulcus procedure uses the subperiosteal plane to create a centralization of the soft tissue matrix, alleviate tension, and redistribute the forces of growth in a more normal pattern. By incising at the level of the alveolus, this approach preserves the blood supply to the osteogenic cells of the buccolabial periosteum. This approach has interesting theoretical implications for the preservation of alveolar growth potential. Arch stabilization and elimination of fistula may be of long-term benefit to the orthodontist.

Adolescent↗

PubMed1988

Detection of three-walled infrabony defects by subtraction radiography.

An in vitro investigation was undertaken to establish the sensitivity of subtraction radiography for three-walled infrabony defect detection. After the creation of defects of controlled sizes in the interproximal regions of a dried mandible, subsequent radiographs were taken with the help of an occlusal stent. The radiographs were then digitized, and the images were enhanced by frame summation and averaging to reduce electronic noise. Further standardization was facilitated by the use of a step wedge on each radiograph and a computer program to correct variations in processing and exposure. The results show that defect resolution depended not only on the diameter of the defect but also on the mass of the adjacent bone. The smallest detectable lesion was 0.5 mm in diameter in the interproximal region of the premolars. In addition, a change in depth of 1 mm could be detected at the base of three-walled infrabony defects.

Alveolar Process↗

PubMed2002

Treatment of furcation defects with an allograft-alloplast-tetracycline composite bone graft combined with GTR: human histologic evaluation of a case report.

The purpose of this study was to histologically evaluate furcation defects in humans treated with an allograft-alloplast-tetracycline composite graft combined with an absorbable membrane for guided tissue regeneration (GTR). Three teeth with Class II furcation involvement on the buccal aspects were included in this study. A notch was placed in calculus during the procedure to serve as a reference point for histologic evaluation. The defects were then treated with an allograft-alloplast-tetracycline composite graft combined with an absorbable membrane for GTR. At 6 months postoperative, the teeth were extracted with conservative block sections and processed for histologic evaluation. Regeneration (new bone, cementum, and connective tissue attachment) coronal to a notch could be seen in one of the three defects treated. In the other two defects, a new connective tissue attachment was demonstrated (new connective tissue attachment into new cementum) in the notch placed in calculus. In this study, regeneration of a furcation defect in a human was documented with histology.

Absorbable Implants↗