Tooth replantation in germ-free and conventional rats

Abstract

Abstract— The purpose of the present study was to evaluate the influence of bacterial infection on the pulpal and periodontal tissues in replanted teeth using germ‐free and conventional rats. Forty maxillary and mandibular first molars from ten 6‐week‐old germ‐free male Wistar rats were used. The animals and all materials were maintained in a germ‐free environment inside vinyl isolators throughout the experimental periods. Twenty conventional male Wistar rats served as controls. The first molars were intentionally replanted immediately after extraction. At 3 days, and 1,2,4 and 8 weeks after replantation, animals were sacrificed and the re planted teeth were histopathologically evaluated. Diversity of pulp tissue response was notable in conventional rats, which initially showed various degrees of neutrophil infiltration and then display ed different types of response, including revascularization with reparative dentin formation and complete necrosis. Pulpal responses of germ‐free rats were less variable, being characterized by an almost complete lack of neutrophil infiltration and a high frequency of bone‐like tissue ingrowth. Typical inffammatory resorption was detected only in conventional rats, whereas a higher incidence of ankylosis was notable in germ‐free rats. The present results may corroborate the concept that bacterial infection is a major cause of serious healing complications following tooth replantation, such as pulp necrosis and inflammatory root resorption. The difficulty in optimally controlling bacterial infection seems to be highly relevant to the complexity and unpredictability of the outcome of this procedure. It should also be emphasized that extensive mechanical damage to the periodontal tissues may trigger the development of unfavorable healing complications as ankylosis, even under strictly aseptic conditions.

Calcific metamorphosis of pulp after extrusive luxation

“…Five different histomorphological events were analyzed: (a) the odontoblast layer; (b) reparative dentin deposition at the coronal, middle, and apical thirds; (c) Hertwig's epithelial root sheath (HERS) on the tooth; (d) pulp necrosis; and (e) periapical inflammatory infiltrate. All of these were defined as: absent; present in a restricted area; partially present; and totally present …”

The role of antibiotics in preventing healing complications after traumatic dental injuries: a literature review

“…With these known trauma/bacteria connections, a logical approach would be to exclude or limit the bacterial load in the healing phase to optimize healing. In classical experiments where bacteria were completely eliminated from the injury site in a germ‐free rat model, surgical pulp exposures in molars were shown to heal spontaneously with hard tissue (6), while in the case of replantation of extracted rat molars, only surface and replacement resorption was seen, not infection‐related resorption (5).…”

Avaliação microscópica do efeito tópico do alendronato e do fluoreto de sódio na superfície radicular de dentes de ratos extraídos e reimplantados tardiamente

“…O processo de reparo após o reimplante tem sido objeto de estudo em numerosos experimentos usando ratos (NISHIOKA et al, 1998;OKAMOTO;OKAMOTO, 1995;OKAMOTO;RUSSO, 1973;PANZARINI, 2001;RENON, 1999), cães (BENATTI NETO, 1984;MURAD, 1982;PERCINOTO, 1986;SONODA, 1997;TROPE et al, 1992), macacos CAFFESSE;NASJLETI;CASTELLI, 1977) e humanos (ALEXANDER, 1956;BODIN, 1990;. A expectativa é que haja o restabelecimento da função do dente reimplantado, entretanto situações adversas podem ocorrer, como a anquilose e as reabsorções radiculares (ANDREASEN, 1985;ANDREASEN, 1992;ANDREASEN, 1994;CAFFESSE;NASJLETI;CASTELLI, 1977 KENNY, 1997;HAMMARSTÖM et al, 1986;NE;WITHERSPOON;GUTMANN, 1999;TRONSTAD, 1988).…”

“…O mecanismo de inibição das reabsorções tem sido atribuído ao decréscimo da atividade osteoclástica por recrutamento diminuído de clastos (BREUIL et al, 1998), à interferência sobre os receptores específicos dos osteoclastos para proteínas da matriz óssea (COLUCCI et al, 1998) FINUCANE, KINIRONS, 2003;HAMMARSTRÖM et al, 1986;NISHIOKA, et al, 1998;TROPE, 2002).…”

“…Outros fatores também devem ser avaliados, como a presença de contaminação microbiana (NISHIOKA et al, 1998), a idade do paciente EBELESEDER et al, 1998), o tipo e o tempo de contenção a ser utilizada após o reimplante dentário (COCCIA, 1980).…”