Microbial colonization in the partially exposed nonabsorbable membrane during alveolar ridge preservation.

AIM: This study evaluated the impact of the partial exposition of the nonabsorbable membrane (dPTFE) on microbial colonization during bone healing. MATERIALS AND METHODS: Patients indicated for tooth extraction were randomized to dPTFE group (n = 22) - tooth extraction and alveolar ridge preservation (ARP) using an intentionally exposed dPTFE membrane and USH group (n = 22) - tooth extraction and unassisted socket healing. Biofilm samples were collected at the barrier in the dPTFE and on the natural healing site in the USH after 3 and 28 days. Samples from the inner surface of the dPTFE barrier were also collected (n = 13). The microbiome was evaluated using the Illumina MiSeq system. RESULTS: Beta diversity was different from 3 to 28 days in both groups, and at 28 days, different microbial communities were identified between therapies. The dPTFE was characterized by a higher prevalence and abundance of gram-negative and anaerobic species than USH. Furthermore, the inner surface of the dPTFE membrane was colonized by a different community than the one observed on the outer surface. CONCLUSION: Intentionally exposed dPTFE membrane modulates microbial colonization in the ARP site, creating a more homogeneous and anaerobic community on the inner and outer surfaces of the membrane. CLINICAL RELEVANCE: DPTFE promoted faster biofilm colonization and enrichment of gram-negative and anaerobes close to the regenerated site in the membrane's inner and outer surfaces. dPTFE membrane can be used exposed to the oral site, but approaches for biofilm control should still be considered. The study was retrospectively registered at Clinicaltrials.gov (NCT04329351).

Carbon nanotubes functionalized with sodium hyaluronate: Sterilization, osteogenic capacity and renal function analysis.

AIM: This study determined the optimum gamma irradiation dosage to sterilize sodium hyaluronate (HY), single-walled carbon nanotubes (SWCNT), multi-walled carbon nanotubes (MWCNT) and CNT functionalized with HY (HY-SWCNT and HY-MWCNT), evaluated the structural integrity of the materials and assessed whether sterilized materials kept biological properties without affecting renal function. MAIN METHODS: Materials were submitted to dosages of 100 gγ to 30 Kgγ and plated onto agar mediums for colony forming units (CFUs) counting. Sterilized samples were inoculated with 107Bacillus clausii, submitted again to gamma irradiation, and plated in agar mediums for CFUs counting. Scanning electron microscope was used for structural evaluation of sterilized materials. Tooth sockets of rats were treated with sterilized materials for bone formation assessment and renal function of the animals was analyzed. KEY FINDINGS: The optimum gamma dosage for sterilization was 250 gγ for HY and 2.5 Kgγ for the other materials without meaningful structural changes. Sterilized materials significantly increased bone formation (p < 0.05) and they did not compromise renal function and structure. SIGNIFICANCE: Gamma irradiation efficiently sterilized HY, SWCNT, MWCNT, HY-SWCNT and HY-MWCNT without affecting structural aspects while maintaining their desirable biological properties.

Comparison of effects of clodronate and zoledronic acid on the repair of maxilla surgical wounds - histomorphometric, receptor activator of nuclear factor-kB ligand, osteoprotegerin, von Willebrand factor, and caspase-3 evaluation.

BACKGROUND: The aim of this study was to compare clodronate and zoledronic acid regarding their influence on the repair of surgical wounds in maxillae (soft tissue wound and tooth extraction) and their relation to osteonecrosis. MATERIAL AND METHODS: Thirty-four Wistar rats were allocated into three groups according to the treatment received: (i) 12 animals treated with zoledronic acid, (ii) 12 animals treated with clodronate and (iii) 10 animals that were given saline solution. All animals were subjected to tooth extractions and surgically induced soft tissue injury. Histological analysis of the wound sites was performed by means of hematoxylin-eosin (H&E) staining and immunohistochemical staining for receptor activator of nuclear factor-kB ligand (RANKL), osteoprotegerin (OPG), von Willebrand factor, and caspase-3. RESULTS: The zoledronic acid group showed higher incidence of non-vital bone than did the clodronate group at the tooth extraction site. At the soft tissue wound site, there were no significant differences in non-vital bone between the test groups. RANKL, OPG, von Willebrand factor, and caspase-3 did not show significant differences between the groups for both sites of surgical procedures. CONCLUSION: Both of the bisphosphonates zoledronic acid and clodronate are capable of inducing maxillary osteonecrosis. Immunohistochemical analysis suggests that the involvement of soft tissues as the initiator of osteonecrosis development is less probable than has been pointed out.

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

UNLABELLED: 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.

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 microg/mL of tetracycline) and other selective media, and were incubated in either aerobiosis or anaerobiosis at 37 degrees C, 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.

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)(AU)

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)