Experimental alveolitis in rats: microbiological, acute phase response and histometric characterization of delayed alveolar healing

The pathogenesis of alveolitis is not well known and therefore experimental situations that mimic some features of this disease should be developed. OBJECTIVE: In this study, the evolution of the experimentally induced infection in rat sockets is characterized, which leads to clinical signs of suppurative alveolitis with remarkable wound healing disturbs. MATERIAL AND METHODS: Non-infected (Group I) and experimentally infected sockets in Rattus novergicus (Group II) were histometrically evaluated regarding the kinetics of alveolar healing. In addition, the characterization of the present bacteria in inoculation material and the serum levels of C-reactive protein (CRP) were performed. The detected species were Capnocytophaga ochracea, Fusobacterium nucleatum ss nucleatum, Prevotella melaninogenica, Streptococcus anginosus, Treponema socranskii and Streptococcus sanguis. RESULTS: All experimentally infected rats developed suppurative alveolitis, showing higher levels of CRP in comparison to those non-infected ones. Furthermore, infected rats presented a significant delayed wound healing as measured by the histometric analysis (higher persistent polymorphonuclear infiltrate and lower density of newly formed bone). CONCLUSION: These findings indicate that rat sockets with experimentally induced infection produced higher levels of serum CRP, showing the potential of disseminated infection and a disturb in the alveolar repair process in an interesting experimental model for alveolitis studies.

Influence of local tetracycline on the microbiota of alveolar osteitis in rats

The aim of the present study was to evaluate the effects of local tetracycline on the occurrence of alveolar osteitis in rats, and on the microbiota associated to this infection. Forty Wistar rats were randomly assigned to 4 groups (n=10): I - the rats had the maxillary right incisor extracted and the alveolar wound did not receive any treatment; II - adrenaline and Ringer-PRAS were introduced into the alveolar wound; III - the alveolar wound was irrigated with sterile saline; and IV - the alveolar wound was irrigated with an aqueous solution of tetracycline. Microbial samples from the alveolar wounds were collected 2 days after surgery and inoculated on blood agar (with and without 8 µg/mL of tetracycline) and other selective media, and were incubated in either aerobiosis or anaerobiosis at 37ºC, for 2 to 14 days. It was verified that tetracycline reduced the occurrence of alveolar osteitis in the rats and caused significant changes in the microbiota of the surgical sites, decreasing the number of anaerobes and increasing the participation of tetracycline-resistant and multi-resistant microorganisms.

O objetivo do presente estudo foi avaliar os efeitos do uso tópico de tetraciclina sobre a ocorrência de alveolite em ratos e sobre a microbiota a ela associada. Quarenta ratos foram divididos, ao acaso, em 4 grupos (n=10): grupo I, realizou-se somente a extração do incisivo superior direito e a ferida alveolar não recebeu nenhum tratamento; grupo II, além da extração dental, soluções de adrenalina e Ringer-PRAS foram introduzidas no interior do alvéolo; grupo III, a ferida alveolar foi irrigada com solução salina estéril; grupo IV, a ferida alveolar foi irrigada com solução aquosa de cloridrato de tetraciclina a 10 por cento. As amostras dos alvéolos para processamento microbiológico foram coletadas dois dias após a realização das cirurgias e foram inoculadas em ágar sangue com ou sem 8 µg/mL de tetraciclina e em outros meios de cultura seletivos, incubadas em aerobiose ou anaerobiose, a 37ºC, de 2 a 14 dias. Verificou-se que a tetraciclina reduziu a ocorrência de alveolite e provocou uma modificação significativa na microbiota do sítio cirúrgico, levando a uma redução nas proporções ocupadas pelos microrganismos anaeróbios e uma elevação da participação de microrganismos resistentes à tetraciclina e outros antimicrobianos.

Normal microbiota of the perialveolar region of incisors of rats / Microbiota normal da região perialveolar de incisivos em ratos

Identificou-se a microbiota normal da região peri-alveolar de incisivos em 72 ratos Wistar, com 70-90 dias de idade e 280-330g de peso. As bactérias foram coletadas com suabes embebidos em solução salina. Do material depositado em tubo contendo 460µl de Brain Heart Infusion e diluído em 1:10, retirou-se 1µl para semeadura em placas de Petri. O crescimento médio foi 1,4x10(6) ± 2,6x10(5)UFC/ml. Segundo a ordem das freqüências, as bactérias encontradas foram: Bacillus sp., Staphylococcus aureus, Streptococcus viridans, Corynebacterium sp., Staphylococcus coagulase negativa, Enterococcus sp., Staphylococcus saprophyticcus, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae e Serratia liquefaciens. De todas as bactérias isoladas, as Gram-positivas e as Gram-negativas compreenderam 91,2 por cento e 8,8 por cento, respectivamente. Dentre as Gram-positivas, a mais freqüente foi Bacillus sp.(31,2 por cento) e a menos, Staphylococcus saprophyticcus (3,0 por cento). Quanto às bactérias Gram-negativas, a mais encontrada foi Escherichia coli (50,1 por cento) e a menos, Serratia liquefaciens (6,2 por cento)

Evaluation of Amoxicillin and Cephalexin concentration in dental alveolar sockets after tooth extraction

One of the most important complications after tooth extraction and oral and maxillofacial surgery is transient bacteraemia and prescription of prophylactic antibiotic is necessary to prevent postoperative infections in immunocompromised patients. The aim of this study was the evaluation of cephalexin and amoxicillin concentrations in dental alveolar sockets following tooth extraction. In this interventional study, 80 healthy patients subjected to tooth extraction were divided into two groups. Each group received 1 gr amoxicillin or cephalexin and teeth were extracted 30-60-90-120-180 minutes after antibiotic intake. Blood sampling was performed immediately after extraction and concentrations of two antibiotics were measured in microbiology laboratory. ANOVA test and Post-hoc [Duncan] test were used for statistical analysis with P<0.05 as the limit of significance. The maximum serum concentration was 10.1006 microg/ml for amoxicillin at 120 minutes and 41.5467 microg/ml for cephalexin at 90 minutes after drug intake. The minimum inhibitory concentration [MIC] of cephalexin and amoxicillin for Streptococcus sanguis was 2 microg/ml and 1 microg/ml respectively. The mean concentration for amoxicillin was 10 times and for cephalexin was 20 times higher than MIC