Wound management and the use of mouth rinse in mandibular third molar surgery.

The aim of this survey was to assess the knowledge and practice of Swiss dentists regarding wound management and the use of mouth rinse in surgical removal of mandibular third molars (MTM). A postal survey was conducted among all 3,288 dentists who are members of the Swiss Dental Society (SSO) representing the majority of dentists in Switzerland. The questionnaire consisted of 13 questions with mostly multiple-choice answers. Demographic profile, surgical experience, the use of antibiotics, and wound management, i.e. wound closure and the use of mouth rinse were assessed. The response rate was 55%. Semi-closed (59.1%), closed (19%) and open wound management (11.7%) were applied most often. Semi-closed wound management was preferred in the German-speaking region (67%) and closed wound management was preferred in the French-speaking region (55%). For semi-closed wound healing, drains impregnated with terra-cortril (42%) and iodoform-Vaseline (40%) were used. For closed wound management, most dentists reported leaving the wound to heal with the blood clot only (60.5%). Most dentists (74.5%) prescribed chlorhexidine 0.2% (CHX) mouth rinse when performing MTM surgery and a combination of immediate preoperative and postoperative use was preferred. Semi-closed wound management with drain and CHX mouth rinse is frequently used in Switzerland in the perioperative management in MTM surgery. It is a well-documented procedure leading to favourable outcomes without using any systemic antibiotics. However, wound management techniques differ between the three linguistic regions.

[Oral pulse granuloma of the mandible- a case report]. / Orales Hülsenfruchtgranulom des Unterkiefers.

The oral pulse granuloma represents a rare form of oral foreign body granulomas and results from encapsulation of particles of vegetable nutrition. Histologically, the oral pulse granuloma consists of multinucleated foreign body type giant cells, hyaline rings and chronic inflammation tissue. Intraosseous granulomas can be distinguished from extraosseous granulo- mas. Intraosseous granulomas are often asymptomatic, whereas the extraosseous type may be clinically apparent as an indolent swelling of the mucosa. Therapy consists of curettage or surgical excision. We report on the clinical, radiological and histopathological characteristics of an oral pulse granuloma in the mandible associated with an erupting tooth 46 of a seven-year-old boy, and the surgical management and follow-up.

Antibiotics in third molar surgery.

The aim of this survey was to assess the knowledge and practice of Swiss dentists focusing on the use of antibiotics in prophylactic surgical removal of lower wisdom teeth. A postal survey was conducted among all 3288 dentists who are members of the Swiss Dental Society (SSO) representing nearly all dentists in Switzerland. The questionnaire consisted of 13 questions with mostly multiple-choice answers. Demographic profile, surgical experience, the use of antibiotics, and wound management, i.e. wound closure and the use of mouth rinse were assessed. A response rate of 55% was obtained. Most Swiss dentists perform surgical extractions in their practices. Of all dentists, 18.6% used antibiotics routinely, but a large variation was found comparing the three linguistic regions of Switzerland with the highest prescription rate of 48% in the French-speaking south-west of Switzerland. Fifty-two percent of dentists prescribed amoxicillin in a dose of 750 mg. Most often three daily doses were prescribed (47%). A postoperative regime was prescribed by 54.4% of dentists. French language (p=0.003), graduation from the university of Geneva (p=0.007), foreign diplomas (p<0.001), and dentists with diplomas awarded from 2001-2006 (p=0.004) showed a highly significant correlation with the use of antibiotics. In Switzerland, prophylactic antibiotics are used in third molar surgery. Antibiotic prescription however largely depends on geographical situation and dentist profiles. The assessment of antibiotic use in private practices is important in the light of growing evidence that antibiotic overuse may lead to development of multiresistant bacterial strains. In a second part results regarding wound management and mouth rinse will be presented.

Studies on recombination processes in two Chlamydomonas reinhardtii endogenous genes, NIT1 and ARG7.

Integration of exogenous DNA in the unicellular green alga Chlamydomonas reinhardtii is principally carried out by mechanisms involving non-homologous recombination (NHR), rather than homologous recombination (HR). Homologous recombination is, however, the mechanism of choice when it comes to gene targeting. Unfortunately, attempts to establish this method in Chlamydomonas have had limited success. In this study we compared two endogenous genes, NIT1 and ARG7, and their HR/NHR ratios when different types of fragments were used as donors of homologous sequences. Transformation of the auxotrophic strain containing the inactivating point mutation arg7-8 with nonfunctional ARG7 gene fragments overlapping this mutation showed increased HR efficiencies when linearized plasmids were used. Efficiency went down rapidly with decreasing length of ARG7 homology. After identification of the inactivating 6726(G→A) point mutation in nit1-305 strains, an analogous set of experiments was performed. In the case of NIT1, overall efficiency of recombination was 10 to 100 fold lower than with ARG7. In order to better demonstrate HR we introduced three silent mutations close to the position of the point mutations in our transforming plasmids. Sequencing of transformants indicated homologous recombination over a short interval.

[Traumatic cyst of the mandible. From development to therapy - a case report]. / Traumatische Zyste des Unterkiefers: von der Entstehung bis zur Therapie. Ein Fallbericht.

Traumatic bone cysts, also referred to as simple bone cysts, solitary bone cysts and haemorrhagic bone cysts, are intraosseous pseudocysts and are categorized by the WHO (2005) as benign, bone-related lesions. Most often young patients under the age of twenty are affected. Symptoms are uncommon and normally the lesion is found in routine radiographic examinations in the mandible. The etiology is still unknown and it has been discussed that trauma, benign tumours or abnormal bone growth might be the cause. Surgical treatment is recommended and recurrence is rare. Histologic features of pseudocysts are a lack of lining epithelium and often an empty bone cavity can be found. The following case report presents a traumatic cyst in the mandible of a 14-year old female patient. Clinical, radiological and histopathological characteristics of this entity will be discussed as well as therapy and follow-up.

[Prevention of the eruption of an upper later incisor by a compound odontoma. Case report]. / Durchbruchsbehinderung eines lateralen Inzisiven im Oberkiefer aufgrund eines zusammengesetzten Odontoms. Ein Fallbericht.

Odontomas are the most common odontogenic tumours. They are considered as hamartomas - a local tissue malformation without autonomous growth potential - and are non-neoplastic. Clinically and histopathologically, compound and complex odontomas can be differentiated. Compound odontomas consist of a varying number of tooth-like structures and histology show dental tissues in an orderly pattern. Most often compound odontomas are diagnosed in young patients in the anterior maxilla. Patients are rarely complaining of symptoms and they are usually diagnosed during routine radiographic examinations or due to late eruption of permanent or persistence of deciduous teeth. The following case report presents a disturbed eruption of a lateral right incisor of the maxilla in a 8-year old female patient. Clinical, radiological and histopathological characteristics of this lesion will be discussed as well as therapy and follow-up.

Genotoxicity and antigenotoxicity evaluation of non-photoactivated hypericin.

The potential genotoxicity and antigenotoxicity of non-photoactivated hypericin was investigated in five experimental models. Hypericin was non-mutagenic in the Ames assay, with and without metabolic activation. It did not exert a protective effect against mutagenicity induced by 9-aminoacridine. In a yeast (Saccharomyces cerevisiae) assay, hypericin did not increase the frequency of mitotic crossovers or total aberrants at the ade(2) locus, the number of convertants at the trp5 locus, or the number of revertants at the ilv1 locus. In combined application with 4-nitroquinoline-1-oxide, it significantly enhanced the number of revertants at the ilv1 locus at the highest concentration used. Hypericin was not mutagenic in the alga Chlamydomonas reinhardtii. However, in combined application with methyl methane sulfonate, toxicity and mutagenicity were slightly reduced. In a chromosome aberration assay using three mammalian cell lines, hypericin did not alter the frequency of structural chromosome aberrations, and in the DPPH radical scavenging assay, it did not exert any antioxidant effects.

Chlamydomonas reinhardtii: a convenient model system for the study of DNA repair in photoautotrophic eukaryotes.

The green alga Chlamydomonas reinhardtii is a convenient model organism for the study of basic biological processes, including DNA repair investigations. This review is focused on the studies of DNA repair pathways in C. reinhardtii. Emphasis is given to the connection of DNA repair with other cellular functions, namely the regulation of the cell cycle. Comparison with the results of repair investigations that are already available revealed the presence of all basic repair pathways in C. reinhardtii as well as special features characteristic of this alga. Among others, the involvement of UVSE1 gene in recombinational repair and uniparental inheritance of chloroplast genome, the specific role of TRXH1 gene in strand break repair, the requirement of PHR1 gene for full activity of PHR2 gene, or encoding of two excision repair proteins by the single REX1 gene. Contrary to yeast, mammals and higher plants, C. reinhardtii does not appear to contain the ortholog of RAD6 gene, which plays an important role in DNA translesion synthesis and mutagenesis. Completed genome sequences will be a basis for molecular analyses allowing to explain the differences that have been observed in DNA repair of this alga in comparison with other model organisms.

Complementation of the Chlamydomonas reinhardtii arg7-8 (arg2) point mutation by recombination with a truncated nonfunctional ARG7 gene.

Chlamydomonas reinhardtii arg7-8 (arg2) mutant strains carrying a hitherto undescribed mutation in their argininosuccinate lyase gene (ARG7) that leads to arginine auxotrophy have been used together with the corresponding wild-type gene as a very reliable transformation system since 1989. In this study, we finally identify the molecular nature of the arg7-8 mutation as a (6073)G to A transition in exon 9 of ARG7 leading to a (288)Gly to Ser exchange near the active site of the protein. The same mutation was found in the ARG7 genes of three commonly used C. reinhardtii laboratory strains, namely cw15-302 arg2, CC-48, and CC-1618. We did not observe exact spontaneous reversion of the arg7-8 allele in our study, but did identify two different and rare intragenic suppressor mutations, (27)Leu to Phe and (285)Tyr to Phe. In our hands, only transformation of the arg7-8 strain with a truncated nonfunctional wild-type ARG7 gene lacking 124 codons at its 5' end led to exact reversion of the mutant base (6073)A to the wild-type (6073)G, presumably by recombination. This system offers a positive selection scheme for homologous recombination (HR) and may, therefore, be useful to the methodical improvement of recombination in Chlamydomonas.

The alga Chlamydomonas reinhardtii UVS11 gene is responsible for cell division delay and temporal decrease in histone H1 kinase activity caused by UV irradiation.

The aim of the present work was to study the possible role of the UVS11 gene of the alga Chlamydomonas reinhardtii, in regulation of the cell cycle. To characterize the defect of a uvs11 mutant in respect to DNA damage-dependent cell cycle arrest, we examined first the influence of the tubulin-destabilizing drug methyl benzimidazole-2-yl-carbamate (MBC) on inhibition of mitosis in response to UV 254nm. Then the growth and reproductive processes and activity of cyclin-dependent kinases (CDK)-like kinases during the cell cycle of C. reinhardtii were investigated. In both, the wild type and the uvs11 mutant strain were compared under standard conditions and after DNA damage caused by UV 254nm. We assume the green alga C. reinhardtii possesses control mechanisms allowing to stop the cell cycle progression before mitosis in response to DNA damage. The results indicate that the uvs11 mutant is not able to stop the cell cycle after UV irradiation. We suggest that a product of the UVS11 gene affects cell response to DNA damage and influences a decrease in histone H1 kinase activity.