Arresting occlusal enamel caries lesions with pit and fissure sealants

The aim of this study was to evaluate the feasibility of pit and fissure sealants and the effectiveness of the two sealant methods applied in every-day practice in public dental health care in Finland. Two sealant methods were evaluated according to their effectiveness in preventing dentin caries and sealant retention. Application time with these sealant methods was compared. The survival rate of sealed first and second molars was followed for nine and 13 year periods, respectively. Caries risk evaluation and observed increased caries risk were the basis for considering sealant application. A questionnaire, sent to all public dental health centers in Finland, monitored the attitudes of the dental profession towards sealant application and explored the current policies used as well as changes noted in the sealant application protocol. DMFT (Decayed, Missing or Filled Teeth) index values collected from the health centers were evaluated. The difference in caries rate between two methods investigated was highly significant. When compared to the glass ionomer sealant method (GIC), the effectiveness of the resin-based method (RB) in preventing dentin caries was 74% and the rate difference 3%. The relative risk for RB-sealed surfaces vs. GIC-sealed surfaces of having detectable dentin caries was 0.3 (95% CI 0.12, 0.57). The retention rate of sealants was higher with RB than GIC (P<0.001). Application of RB sealant material was less time-consuming than application of GIC sealant. Occlusal dentin caries lesions were found in 4% and proximal caries in less than 2% of sealed teeth. The majority of respondents reported application of sealants on a systematic basis along with caries-risk evaluation. Those health centers sealing over suspected or detected enamel caries had lower average DMFT index values (1.0) when compared to DMFT values (1.2) of health centers applying sealants by alternative criteria. It is concluded that the RB sealant method is more effective than the GIC sealant method in preventing dentin caries. Sealant maintenance may increase the costs of a sealant program. Occlusal caries management may be improved if the applied sealant policies are changed towards an interceptive approach i.e. applying the sealants over detected or suspected enamel caries lesions instead of sealing sound teeth in a preventive manner.

Characterisation and processing of amorphous binary mixtures with low glass transition temperature

The number of drug substances in formulation development in the pharmaceutical industry is increasing. Some of these are amorphous drugs and have glass transition below ambient temperature, and thus they are usually difficult to formulate and handle. One reason for this is the reduced viscosity, related to the stickiness of the drug, that makes them complicated to handle in unit operations. Thus, the aim in this thesis was to develop a new processing method for a sticky amorphous model material. Furthermore, model materials were characterised before and after formulation, using several characterisation methods, to understand more precisely the prerequisites for physical stability of amorphous state against crystallisation. The model materials used were monoclinic paracetamol and citric acid anhydrate. Amorphous materials were prepared by melt quenching or by ethanol evaporation methods. The melt blends were found to have slightly higher viscosity than the ethanol evaporated materials. However, melt produced materials crystallised more easily upon consecutive shearing than ethanol evaporated materials. The only material that did not crystallise during shearing was a 50/50 (w/w, %) blend regardless of the preparation method and it was physically stable at least two years in dry conditions. Shearing at varying temperatures was established to measure the physical stability of amorphous materials in processing and storage conditions. The actual physical stability of the blends was better than the pure amorphous materials at ambient temperature. Molecular mobility was not related to the physical stability of the amorphous blends, observed as crystallisation. Molecular mobility of the 50/50 blend derived from a spectral linewidth as a function of temperature using solid state NMR correlated better with the molecular mobility derived from a rheometer than that of differential scanning calorimetry data. Based on the results obtained, the effect of molecular interactions, thermodynamic driving force and miscibility of the blends are discussed as the key factors to stabilise the blends. The stickiness was found to be affected glass transition and viscosity. Ultrasound extrusion and cutting were successfully tested to increase the processability of sticky material. Furthermore, it was found to be possible to process the physically stable 50/50 blend in a supercooled liquid state instead of a glassy state. The method was not found to accelerate the crystallisation. This may open up new possibilities to process amorphous materials that are otherwise impossible to manufacture into solid dosage forms.

Looking-Glass Reflections : Norms in translating Lewis Carroll

This thesis in the field of translation studies focusses on the role of norms in the work of a literary translator. Norms are seen as guidelines for the translator; they also reflect the way the target audience either accepts or rejects the translation. Thus they are of an intersubjective nature. The theoretical background of the study is based on the views on norms of Andrew Chesterman and Gideon Toury. The writer makes use of her own editing and publishing experience, as well as her experience in translating Lewis Carroll, considering these in respect to theoretical views of norms and vice versa. The aim is also to bring to light some of the tacit knowledge related to translating, editing and publishing in Finland. The study has three angles. First, the writer introduces the norms of Finnish literary translation as gathered from her own working experience. The sources from which these norms arise and which affect them are briefly described. Six central translation norms emerge; they are described and exemplified through cases of Carroll translation. Secondly, a small-scale questionnaire study is presented. This was carried out in order to sound the normative views of other translators and to limit the role of subjectivity. The views of the informants largely support the set of norms presented by the writer, although the norms of quotability and harmony between translation and illustration do not arise. Instead, the answers give rise to a seventh, ethical norm, which is labelled the norm of integrity. Thirdly, there is a brief presentation of Lewis Carroll, his Alice books and their translation history in Finland. The retranslation hypothesis and the motives of retranslation are considered in the light of the work of Outi Paloposki and Kaisa Koskinen. The final part of the thesis plunges into actual translation work. It includes one and a half chapters of Through the Looking-Glass (Alicen seikkailut peilintakamaassa) as translated into Finnish by the writer. The translation commentary first discusses a number of recurring and general translation points; the running commentary then analyses 77 individual translation solutions and their justifications. The writer uses introspection as a way of reflecting on her own translation process, its decisive points and the role of norms therein. Keywords: Translation studies, Carroll, norms