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I discuss the nature of serial homology. Mammalian teeth have a relatively dense fossil record, which permits an often close reconstruction of the evolution of patterns of serial homology. I identify the main crests of mammalian teeth, summarize their evolution, and provide new names where necessary. Serial homologies can change in evolution, originate, and disappear. They can be partial, unlike historical homologies. Teeth exemplify these phenomena, and their patterns can be viewed topologically as well as in other ways. Some, but not all, crests and cusps of upper teeth appear to be homologous to structures of lower teeth. The pure morphology of Goethe is a living science.
Boar tusks are hypsodont teeth which undergo permanent wear on the incisal portion and growth at their basal part. They serve not only as a defense, but also as a tool for rooting and obtaining food. The paper presents lesions in boar tusks characterized by bilateral ledge formation on mandubular and maxilar canines that demarcated incisal from basal tooth portions. The lesions are probably the consequence of ameloblasts and odontoblasts alteration in the proliferative area with transient functional inhibition. Renewed cell activity leads to the rebuilding of the basal tooth part. This phenomenon can become noticeable as a circular ledge. In some cases pulpitis can result as a complication of the process, but it is not an integral part of the lesions. The bilateral character of the changes suggests a hematogenic means of pathogen action. However, its etiology still remains unclear. Ameloblasts are very sensitive to vitamin A, calcium and copper deficiency, as well as to the toxic influence of fluoride. One of the important pathogen agents seems to be mycotoxins, which are often taken in by boars with molded food.
This in vitro study evaluated temperature rises on the outer root surfaces of cats canine teeth during the Thermafil Plus filling technique. Twelve extracted cat canine teeth were used. After root canal cleaning and shaping, the teeth were filled with Thermafil Plus and AH Plus root canal sealer. Temperature changes on the whole mesial outer surfaces of the roots were measured using an infrared thermal imaging camera. The results of this in-vitro study showed that the use of the Thermafil Plus technique to fill canine teeth in cats produces a temperature rise below the critical level and therefore should not damage the periodontal ligament and/or the surrounding attachment apparatus.
Lingualy displaced mandibular canines, resulting in the change of vestibular axial inclination into one parallel to the sagittal plane, occur relatively seldom among malocclusions. This sort of displacement is qualified - beside isolated rotations as well as frontal or lateral cross-bites - as a class I malocclusion and is susceptible to treatment provided the etiology is not a hereditary one. There are off-genetic factors leading to malocclusion, such as persistent deciduous canine, trauma coinciding with tooth-eruption, narrowing of the mandible or its underdevelopment in a transversal dimension and vestibular displacement of the erupting upper canine. The described ectopy leads to a mechanic leisure of gingival and palatal tissues. Protection of the dog against those side effects calls for either interceptive or regular treatment based on gingivoplasty, orthodontic therapy, shortening of the canine crown and - in extreme cases - extraction of causal teeth.
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