Mesenchymal stem cells as active prohealing and immunosuppressive agents in periapical environment: evidence from human and experimental periapical lesions.

INTRODUCTION: Previous studies describe contrasting molecular profiles of active and inactive periapical granulomas characterized by distinct expression of cytokines, osteoclastogenic factors, and wound healing markers. Although the molecular mechanisms underlying such a dichotomy remain unknown, in this study we investigated the potential involvement of mesenchymal stem cells (MSCs) in determining human and murine periapical lesion activity and outcomes. METHODS: Periapical granulomas (n = 83) and control samples (n = 24) were comparatively assessed for the expression levels of 11 mesenchymal stem cell (MSC) markers using real-time polymerase chain reaction. Experimental periapical lesions induced in mice were evaluated for MSC marker expression and the effects of AMD3100 treatment on lesion outcomes. RESULTS: MCS marker expression was prevalent in periapical granulomas compared with that in controls, whereas CD29, CD73, CD90, CD146, CD166, NANOG, Stro-1, and CXCR4 expressions were higher in inactive than in active lesions. Experimental periapical lesion inactivity was also associated with an increased expression of MSC markers. The inhibition of MSC mobilization to the periapex by AMD3100 resulted in increased lesion sizes; decreased expression of MSCs and wound healing markers; and increased expression of interleukin 1 beta (IL-17ß), interleukin 17 (IL-17), tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and nuclear factor kappa-B ligand (RANKL). CONCLUSIONS: Our results show that MSC markers are overexpressed in inactive human and experimental periapical lesions and that MSC mobilization results in the attenuation of experimental lesion progression associated with immunosuppressive and prohealing mechanisms.

Treatment of a large periradicular lesion of endodontic origin around a dental implant with enamel matrix protein derivative.

BACKGROUND: This case report describes the healing of a large periradicular lesion involving an adjacent implant. Endodontic surgery was performed in combination with placement of an enamel matrix protein derivative. METHODS: Endodontic surgery was performed, including root end resection at a 90 degrees angle. Ultrasonic tips were used for retrograde preparation, and the retrograde cavity was sealed with zinc oxide-eugenol. The area was filled carefully with enamel matrix proteins. Sutures were removed after a 2-week healing period. RESULTS: There were no symptoms of pain, inflammation, or discomfort at 18 months post-surgery. Radiographs showed complete healing of the periradicular lesion. CONCLUSIONS: Combining an enamel matrix protein derivative with conventional surgery may improve the clinical outcome of large endodontic lesions. Additional research is warranted.

Bacteriologia das periodontites apicais crônicas após utilização da medicação intracanal / Bacteriology of chronic apical periodontitis after using intracanal medication

Este estudo tem como propósito avaliar a efetividade antibacteriana de diferentes tipos de medicação intracanal: hipoclorito de sódio 1 por cento, pasta de hidróxido de cálcio, gel de clorexidina 2 por cento e paramonoclorofenol canforado. O tratamento endodôntico foi realizado e o dente permaneceu com a medicação intracanal durante sete dias. Após esse prazo, foi relaizado isolamento absoluto do dente e uma solução estéril foi introduzida e aspirada do canal radicular. O material aspirado foi semeado nos meios agar sangue, Mac Conkey e azida sódica, para identificação de aeróbios, e nos meios agar sangue Brucella, agar sangue fenil etanol e tioglicolato, para a identificação de anaeróbios. A incubação e identificação dos microorganismos foram realizados na Unidade de Microbiologia do Hospital de Cínicas de Porto Alegre. Em relação à efetividade antimicrobiana das quatro medicações intracanal testadas, encontram-se 100 por cento de casos negativos para anaeróbios com todas as medicações. Para os micoorganismos aeróbios, or sultado mais favorável foi com o uso do hidróxido de cálcio (100 por cento de casos negativos); já, poara a clorexidina e para o paramonoclorofenol conforado, ocorreram 60 por cento de casos negativos. O hipoclorito de sódio apresentou 100 por cento de casos positivos para aeróbios. Os microorganismos aeróbios encontrados foram: Klebsiella oxytoca, Streptococcus sp. alfa homolítico, Enterococcus sp., Enterobacter sp., Strepcoccus sp. (grupo viridans), Streptococcus sp. anemolítico e Escherichia coli. Verificou-se com este estudo que, apesar dos remanescentes bacterianos encontrados, as medicações testadas apresnetaram alguma ação antimicrobiana

Chlorhexidine as a root canal medicament for treating inflammatory lesions in the periodontal space.

The purpose of the present study was to investigate the therapeutic effect of intra-canal application of chlorhexidine on inflammatory root resorption. Dental pulps from monkey incisors were infected and resealed prior to extraction of the teeth. Root dentin was mechanically exposed and the teeth were replanted under aseptic conditions. After 4 weeks, the experimental teeth were dressed with chlorhexidine gel and resealed. Animals were sacrificed 4 weeks later, and their jaws prepared for histologic examination. Results showed that both marginal and apical periodontal inflammation and resorption were reduced in the chlorhexidine-treated teeth. It was concluded that the use of intra-canal chlorhexidine may be a useful adjunct in the treatment of inflammatory root resorption, but further human trials need to be undertaken before its clinical use can be recommended.

Identification and antibiotic sensitivity of bacteria isolated from periapical lesions.

Periradicular tissues from 28 refractory endodontic cases requiring surgical intervention were submitted for histological diagnosis and microbiological culture. Bacteria isolated from these lesions were identified and then tested for their antibiotic sensitivity to a panel of common antibiotics. The periapical tissue specimens of 22 out of 28 lesions (79%) contained microorganisms. Of the 22 cases showing positive growth cultures, 15 were polymicrobial and 7 were single species isolates. Fifty-three different species were recovered: 29 anaerobes, 19 facultative anaerobes, and 5 aerobes. Microbes were observed under light microscopy in only one case. The most common organisms isolated were Propionibacterium acnes, Staphylococcus epidermidis, Streptococcus intermedius, Wolinella recta, Fusobacterium species, and Clostridium species. Antibiotic susceptibility results showed no clear cut evidence of significant antibiotic resistance among the species tested. The results of this study seem to corroborate earlier studies regarding the microbial population of periapical lesions refractory to nonsurgical endodontics.

[The modern approach to the treatment of periodontitis]. / Nekotorye aspekty sovremennogo podkhoda k lecheniiu periodontita.

For the treatment of patients with chronic and exacerbated periodontitis trichopol and lincomycin were used as well-known effective antibacterial drugs in anaerobic non-clostridial infection. Zinc-eugenol paste was added. The results were favourable.

Ampicillin concentrations in human radicular granuloma following a single oral dose of bacampicillin.

Ampicillin concentrations in human serum and radicular granulomas of 42 patients were determined after a single oral dose of bacampicillin (equivalent to 500 mg of ampicillin). Although wide variations were found among both serum and radicular granuloma ampicillin concentrations, measurable concentrations were found in all cases. The mean peak ampicillin concentrations in serum and radicular granulomas occurred at identical times, 1.5 hours, and were 11.19 micrograms/mL (range, 1.30 to 21.00 micrograms/mL) and 5.12 micrograms/g (range, 0.50 to 10.50 micrograms/g), respectively. The mean radicular granuloma/serum ampicillin concentration ratio at the peak time was 0.42. Ampicillin concentrations in radicular granulomas exceeded most of the minimum inhibitory concentrations for bacteria commonly isolated from odontogenic infections.

[Periapical lesions treated with CaO. Histological controls]. / Lesioni periapicali trattate con CaO. Controlli istologici.

The results of histological examinations conducted on 2 granulomas found in teeth and treated with calcium oxide are reported. It is concluded that the treatment produces significant changes in the histological picture with the formation of scar tissue that precedes the growth of newborn in a relatively short time.

[Indices of microorganism sensitivity to antiseptics in apical periodontitis]. / Pokazateli chuvstvitel'nosti mikroorganizmov k antiseptikam pri apikal'nom periodontite.

High incidence of detection of staphylococci aur. and epiderm.; streptococci hemolyt. and virid., and gram-negative microorganisms in dental root channels in periodontic patients was established. Among antiseptic drugs, most toward major periodontal++ initiators were pervomur, iodopyrone, chlorhexidine, ethonium.

[Validation of the choice of antibacterial agents for treating periodontitis]. / Obosnovanie vybora antibakterial'nykh sredstv dlia lecheniia periodontita.

Sensitivity of microflora sampled from the dental root channels of periodontitis patients to chlorhexidine, dioxidine, quinosol, Metrodgile was investigated. Chlorhexidine and dioxidine were shown to act predominantly on gram-positive and gram-negative bacteria, Metrodgile most active against anaerobic flora. High antibacterial activity of quinosol and chlorhexidine was combined with their pronounced cytotoxic effects. Metrodgile could be successfully used for preventing purulent odontogenic inflammations caused by anaerobic flora.

[Use of a new cobetalactamine in the therapy of acute and chronic odontogenic processes]. / Impiego di una nuova cobetalattamina nella terapia di alcuni processi acuti e cronici odontogeni.

Treatment of 70 patients with acute and chronic odontogenic processes for 5-35 days (mean 10.9 days) with a new cobetalactamine is reported. Rapid resolution was noted in nosological groups marked by the presence of acute infection. Particular interest is attached to the effect of the drug on chronicisting infections, such as apical granuloma, maxillary osteitis, and radicular cysts, since these forms displayed a high degree of vascular isolation, were often sustained by a mixed flora, and had been previously treated with other antibiotics. Follow-up four weeks after the conclusion of treatment showed a low incidence of recurrences that was in all events lower than in earlier experiments with chemical antibiotics. There were no instances of intolerance or allergy.

[Use of chlorhexidine in the therapy of some stomatological diseases]. / Impiego della clorexidina nella terapia di alcune affezioni stomatologiche.

A mouthwash or toothpaste containing chlorhexidine gluconate was used to treat spontaneous or provoked bacterial plaque, primary or postoperative secondary gingivitis, and aphthae in 74 male and female subjects (mean age: 37 yr). As observed by other authors the antiseptic was very effective in the prevention of plaque, the healing or primary gingivitis, and the cicatrisation of surgical wounds. It also accelerated the regression of recurrent aphthae.