PubMed Health⌕ Search

Biomedical subjects

J J Lasfargues

Publications and source records attributed to J J Lasfargues.

At least 19 recordsLinked to original sources
PubMed1992

Effects of prostaglandin inhibition on the bone activities associated with the spontaneous drift of molar teeth in the rat.

Little is known about local bone regulation that enables spontaneous molar tooth drift. In this study the role of prostaglandins (PGs) were investigated in the rat by inhibiting PG-synthesis with indomethacin (7 mg/kg/d). Untreated animals were killed at the start of the experiment, while treated ones were killed after 3, 7, or 14 days of treatment. Mandibles were processed for histomorphometry without demineralization. Changes in osteoclasts and extent of the different steps of the bone remodeling sequence (resorption, reversal, and formation) were assessed along the remodeling side of the socket of the buccal root of the first molar. The total number of osteoclasts decreased after 7 days of PG inhibition (P < 0.01 vs controls) and then partially recovered. This change was due to a sharp decrease in active cells on day 7 (P < 0.01), while inactive cells remained unchanged throughout the experimental period. The extent of resorption fell on day 7 (P < 0.01) and then recovered almost to the control level on day 14. Reversal at first increased insignificantly and thereafter decreased (P < 0.02) for the remaining 7 days. Formation was modified only on day 14; at that time it had doubled compared with controls. These results show that PGs are involved in the local regulation of bone remodeling accompanying tooth drift. Resorption inhibition was partial, indicating that other factors participate with PGs in this regulation; in addition, the trend to recovery observed at the end of the experimental period suggests that these factors can take over from PGs to achieve the necessary remodeling of the socket.

Alveolar Process↗
PubMed1990

[Pulpectomy. Why? When?].

There are many circumstances under which the condition of the pulp calls for root canal work, due to the real or potential risk of pain, infection, inflammation or functional difficulties (acute, irreversible pulpitis, chronic pulpitic conditions, necrosis and its consequences, etc.). Other circumstances exist in which injury to the pulp is not necessarily irreversible: initial pulpitis, iatrogenic fracture of the pulp, traumatisms, dystrophic deteriorations. The high success rate for endodontic therapy could argue for elimination of impaired or necrose-prone pulp. In fact, however, unsuccessful pulpectomies often lead to loss of the dental organ and successful endodontic treatment severely weakens the whole tooth structure and often implies prosthetic restoration, with the consequent increase in tissular loss. In order to preserve pulp and crown tissues, pulpal vitality should be protected in all cases where such conservative efforts do not worsen the prognosis for maintaining the tooth on its arch or jeopardize a planned restoration. Solutions are presented for various types of situations, according to the risks encountered.

Contraindications↗
PubMed1990

[Prognosis of canal treatment. Success and failure].

This clinical review confirms the very positive prognosis for endodontic therapy, conditional to strict compliance with imperatives. Endodontics failures are transient and can be remedied. The authors define the attitude to be adopted and the measures to be taken in accordance with the type of difficulty encountered.

Humans↗
PubMed1990

[Conservative restoration of pulpectomized teeth].

In endodontic treatment of teeth, partial or "conservative" crown reconstructions are clinically acceptable where loss of substance is limited and recourse to radicular pivots is contraindicated. Such reconstructions bring into play a variety of currently available biomaterials, including those inserted in the plastic phase. They make it possible to delay a prosthetic solution (full crown restoration) without impinging on the conservation of the devitalized tooth.

Composite Resins↗
PubMed1990

[Preparations for anterior composites].

This paper sets forth and discusses the various preparations used in aesthetic restoration of anterior teeth with composite resins. The clinical description of contours involves treatment of class III and IV carious lesions and correction of aesthetic imperfections which justify resorting to direct techniques of cosmetic dentistry.

Composite Resins↗
PubMed1990

[Marginal adaptation of posterior composites. A complex clinical problem].

In this article, the authors deal with the problem of marginal fit for posterior composites, where direct class-II aesthetic restoration is involved. For different materials, they analyse and discuss the influence of their physicochemical properties, the contour of preparations, and composite handling. Three types of clinical cases are described: preparation using the tunneling technique, adhesive preparation, conventional preparation.

Bicuspid↗
PubMed1990

[Composite resin inlays. Convincing solution or uncertain compromise?].

This is a report on the authors' clinical experience years of using laboratory composites. They describe the contours of composite resin preparations for inlays, discuss the advantages drawbacks of such restorations and provide limited indications. The illustrations also involve specific clinical cases.

Acrylic Resins↗
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↗