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J L Saffar

Publications and source records attributed to J L Saffar.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Arachidonic acid derivatives in periodontitis].

A myriad of mediators of inflammation are involved in the onset and progress of periodontal disease. The exact roles of some of them are understood nowadays. In this paper, the current knowledge on the products of the arachidonic acid cascade (i.e. prostaglandins and leukotrienes) is reviewed. The main interests of these mediators are in their potential in diagnosing the phases of activity of periodontitis and the therapeutic prospects that their inhibition open up.

Arachidonic Acids↗
PubMed1989

Periodontal and femoral bone status in periodontitis-affected hamsters receiving a high dose indomethacin treatment.

The aim of this study was to test the effect of a high dose (6 mg/kg/d) of indomethacin, a PG-synthesis inhibitor, on hamster periodontitis and to verify a possible systemic skeletal action. Thirty animals were separated into three groups: control, untreated periodontitis-affected, and indomethacin treated groups. Compared to affected untreated animals, indomethacin reduced the number of osteoclasts (p less than 0.001) to the control level, and accordingly the extent of resorption (p less than 0.01). A partial decrease in reversal (p less than 0.05) was also obtained; the persistence of aborted reversal lacunae was the scar of the pretreatment period. The extent of formation was markedly increased by indomethacin (p less than 0.01). Bacterial plaque accumulation was not modified but PMNLs investing plaque were dramatically decreased (p less than 0.02). Indomethacin had no influence on the femoral periosteal remodeling, nor on metaphyseal and epiphyseal trabecular density, nor on growth plate thickness. These results confirm the positive effect of indomethacin on hamster periodontitis and emphasize the role of PGs on periodontitic bone disturbances, particularly on the uncoupling of the remodeling sequence. The reduction in PMNL migration is an important feature, which possibly participates in the improvement of the bone status. The lack of femoral changes indicates that a mid-term treatment with indomethacin has no detrimental action on ordered skeletal growth and bone mass.

Alveolar Process↗
PubMed1988

Role of prostaglandins in bone resorption in a synchronized remodeling sequence in the rat.

The role of prostaglandins (PGs) in physiological remodeling has not yet been defined. The present study was undertaken to determine whether they intervene during the activation phase in a highly reproducible and synchronized model of bone remodeling. Indomethacin was employed to inhibit PG synthesis. This treatment throughout the entire activation period (4 days in this model) inhibited osteoclastic resorption completely. By modifying the treatment procedure, it appeared that PGs were operative mainly between the second and third day of activation. PGs did not seem to act on precursor recruitment, since off-bone osteoclasts (putatively inactive cells) were numerous in the treated groups. PGs might also be involved in osteoclast activity as the mean interface between osteoclasts and bone surface was reduced in the treated groups. However, indomethacin was unable to inhibit the remodeling sequence durably since a 6-day treatment resulted in a high profile of resorption. This suggests that factors other than PGs were responsible for activating resorption.

Animals↗
PubMed1988

[Root reactions during treatment with indomethacin in the rat].

During the course of a study on the effect of indomethacin, an inhibitor of PG-synthesis, on the alveolar bone remodeling associated with the drift of the rat molar, the root profile appeared altered. The perimeter of the buccal root of the lower first molar had increased during the 7-day experimental period (+9%; p less than 0.02) in the treated group. This was due to an increase in the extent of root resorption lacunae (+99%; p less than 0.05). They were located in the disto-buccal aspect of the root, i.e., facing the alveolar wall remodeling area. The periodontal ligament width was also increased (p less than 0.001). This might be an adaptative process to maintain the periodontal ligament width as the drift of the teeth had not ceased while the remodeling had markedly slowed down. These results show that the osteoclastic population responsible for root resorption was not PG-dependent, unlike that active on alveolar wall. In addition, dentin deposition was accelerated in the pulp area underlying the resorption lacunae in the treated group as shown by measuring the distance between two fluorescent labels incorporated in a 6-day interval (p less than 0.05).

Alveolar Process↗
PubMed1987

[The respective roles of occlusal abrasion and bacterial plaque in the etiology of alveolar lysis in periodontitis in hamsters].

This study was designed to determine the respective roles of occlusal attrition and subsequent tooth egression, and bacterial plaque accumulation on bone loss (or radicular denudation) during hamster periodontitis. Seventy young male animals were separated into 7 groups. Occlusal attrition was compared on 3 different diets (standard in pellet form, standard in powder form, and Keyes 2000 in powder form), thought to have different abrasiveness. The role of bacterial plaque wad evidenced by inhibiting it with Penicillin V in animals fed the same 3 diets. Compared to animals killed at the beginning of the experimental period (absolute controls), 3 months later bacterial plaque was slightly increased in hamsters fed the standard diet, very markedly increased in 2000 diet-fed animals and, decreased in the 3 antibiotic treated groups. Occlusal attrition was increased in the 2 groups fed the standard diets but not in the 2000 diet-fed animals. Radicular denudation was slightly increased in the standard diet groups, very markedly increased in the 2000 diet group, and unchanged in the antibiotic treated animals. Thus, the less abrasive diet was associated with the greatest plaque accumulation and bone loss; conversely, with the most abrasive diets, radicular denudation had slightly progressed with only small amounts of plaque. This suggests that in hamster periodontitis, bone loss is not influenced by occlusal attrition but is completely dependent on the direct action of bacterial plaque.

Alveolar Process↗
PubMed1987

[Tooth grafts in the dog: effect at mid-term of preservation of the periodontal ligament on root and alveolar remnants].

This work was undertaken to study at middle term (5 months) the behaviour of radicular grafts implanted in newly formed sockets. In some of the grafts, the remnants of the periodontal membrane were carefully preserved in a wet medium while in the others the root surface was curetted and dried. Preservation of the periodontal tissues allowed the organization of a periodontal space. This new periodontal ligament was occasionally functional with fibres in continuity from cementum to bone. Generally it was not functional with the fibres laying parallel to cementum and bone surfaces. Early "surface resorption" of the root was prevented as well as ankylosis leading to replacement of root with bone. The extent of ankylosis was reduced. It was localized to the buccal and lingual aspects of the roots where the periodontal ligament was disorganized during the extraction procedure. In the non preserved roots, ankylosis was almost total. Roots were in part replaced with bone. At 5 months, this process was still in progress.

Alveolar Process↗
PubMed1986

Destruction and repair of periodontal tissues during burst episodes of activity in hamster periodontitis.

This study describes episodes of rapid destruction and repair of periodontal tissues occurring during the course of hamster periodontitis. The mandibular molar periodontia of 120 male golden hamsters exposed to Keyes 2000 diet for periods ranging from 45 to 180 days were examined on undecalcified serial sections. The destructive phase of the episodes was characterized by the localized appearance of a large number of osteoclasts creating a cone-shaped defect. Bone resorption was associated with disorganization of the gingival tissues, including epithelial ulceration, and a dense PMN infiltration. The repair phase was observed in these cone-shaped defects by the use of fluorescent and corresponding stained sections. Bone formation was intense with woven bone filling the cervical aspect of the defect. Apically, bone formation was more regular and less rapid. A healthy band of connective tissue always separated the bone reaction from the infiltrated connective tissue. Despite its magnitude this repair did not restore the overall bone destruction. The burst episodes of activity were found far more frequently in animals with significant macroscopic bone loss. They mobubly play a key-role in the progress of alveolar destruction in the hamster.

Animals↗
PubMed1986

[Bone dynamics].

Explore the source record for details and available documents.

Bone Resorption↗
PubMed1986

A morphological and quantitative study of osteoclast changes during the progress of periodontitis in the hamster.

Since macroscopic bone loss in hamster periodontitis appears to be a continuous process, this study was undertaken to evaluate whether osteoclastic resorption is continuously activated or whether another pattern of activation occurred during the course of the disease. At the beginning of the experimental period, 5 male golden hamsters were killed; they were used as to controls. Forty other animals were then distributed into 2 equal groups. In the experimental group, periodontitis was induced by using the Keyes 2000 diet. Five animals in both control and experimental groups were killed at 45, 90, 135 and 180 days. The following parameters were quantitated in the mandibles: - the macroscopic bone loss, - the number of osteoclasts in contact or lying at a distance from bone, and - the number of nuclei per mm of bone surface. Control animals developed spontaneous, slowly progressing periodontitis. In the experimental animals, osteoclasts were more numerous along the periosteum than along the endosteal surfaces. The mean increase in active osteoclasts appeared to be almost stable throughout the experimental period after an initial marked increase along the periosteum. However from the morphological data, when each animal was examined individually, it appeared that osteoclastic activity varied from place to place along the bone surfaces. These findings, further supported by the large quantitative intra-group variations that we observed in this study as well as in our previous studies, suggested that although the disease progressed regularly at the macroscopic level, osteoclastic activity was rather discontinuous and recurrent.

Alveolar Process↗
PubMed1986

[Sequence of experimental remodeling of the mandibular periosteum in the rat].

The evolution of a synchronous bone remodeling sequence has been followed with time. This sequence was induced in the buccal mandibular cortex of the rat which undergoes modeling apposition after maxillary molar extractions. The sequence has been studied in the rat on day 0, 2, 4, 6, 8 and 12 after induction. Disappearance of the layer of osteoid tissue produced on day 0 was initially observed (day 2). The resorption phase reached a peak on day 4 and then decreased until day 12. The greatest inversion was observed on day 8 and then regressed. Apposition, completely absent on day 4, was again important on day 12. The variations with time of the 2 different osteoclast profiles, those in contact with bone (considered as active) and those at a distance from the bone surface (considered as inactive) allowed to study the kinetics of these cells. Whereas their total number was unchanged on day 4 and 6, on day 4 the active osteoclasts were more numerous: this situation was completely reversed on day 6. These facts suggest that the osteoclasts present were active for 1 to 2 days, then became inactive without change in number before their disappearance. This very reproducible model seems useful for understanding certain mechanisms occurring during bone remodeling and for testing the role of some mediators or pharmacological agents on the process.

Animals↗