Maxillary incisors in 47 monkeys, 54 in the experimental group (I) and 117 in the control group (II), were extracted and reimplanted, either immediately or after 30 or 60 min wet or dry storage. Incisors in the experimental group I were additionally kept 5 min in a suspension of 1 mg doxycycline in 20 ml physiologic saline, freshly prepared for each of the 15 animals before reimplantation. The observation time varied from 6 to 8 weeks. The teeth were removed in tissue blocks, histologically processed and evaluated for occurrence of complete pulp revascularization (CPR), presence of the micro-organisms in the pulpal lumen and ankylosis or inflammatory root resorption. Then the results were statistically evaluated, using log-linear analyses and chi-square tests (SAS, 1985) for the comparisons between group I and group II. These analyses revealed that topical application of doxycycline increased the frequency of complete pulp revascularization (P less than 0.002) and decreased the frequency of micro-organisms in the pulpal lumen (P less than 0.001). Furthermore, the frequencies of ankylosis (P less than 0.05) and inflammatory root resorption (P less than 0.001) were also decreased compared with the control group of teeth. It was concluded that the effect of topical treatment with doxycycline was most probably exerted on the micro-organisms that contaminated root surface during the extra-alveolar time; contamination of necrotic pulp tissue from the mechanical damage in the cervical part of the root surface was not affected.

A system is described for estimating the age of the African lion by studying the eruption sequence of deciduous and permanent teeth of both jaws and the wear of permanent teeth. This system is supplemented by observing criteria such as height of the cemento‐enamel line of permanent canines above the alveolar margin, the closure of the apical foramen of the pulp chamber and the discolouration of permanent teeth. Where skulls are available curves and equations describing closure rate with age of the pulp chambers of maxillary and mandibular canines measured at their maximum mesio‐distal width, are provided. These measurements can be taken by either sectioning the canines transversely at a certain point or by X‐raying the teeth. Sex‐specific von Bertalanffy growth curves and equations describing skull growth with age for four skull measurements are also provided while the use of cranial sutures for age determination in the lion is evaluated. Canine root sections were removed, decalcified, sectioned and stained for incremental cementum line counts. The results of this method were in close agreement with the ages of known‐age lions and those aged by the previously mentioned methods (r=0.973; P<0–001). A series of photographs and a description is provided whereby lions observed in the field can be classified into age classes. Sexual dimorphism in the permanent canines is described and appropriate measurements given whereby a single permanent canine can be used to decide on the sex of an animal. The use of oxytetracycline and lead acetate for the in vivo“labelling” of teeth in wild lions is examined.

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In 32 monkeys 105 immature maxillary incisors were extracted and reimplanted either immediately or after 30 or 60 min wet or dry storage. Of the monkeys, 17 (group I) did not receive and 15 (group II) received prophylactic treatment with 4 mg/kg doxycycline before extraction and 2 mg/kg for 5 d after reimplantation. The observation time varied from 6 to 8 weeks. After being histologically processed, the material was evaluated with respect to the amount of vital tissue and presence of micro-organisms in the pulpal lumen. A comparison revealed no difference in the results between the groups. The results were therefore pooled and statistically analysed with respect to the significance of apical foramen width, extra-alveolar time, wet or dry storage and presence of micro-organisms in the pulpal lumen for the occurrence of complete pulp revascularization (CPR). The overall frequency of CPR was 18%. Log-linear analyses (SAS, 1985) of the material as a whole or of separate parameters consistently revealed a relationship between presence of micro-organisms and absence of CPR (P = 0.0001). A higher frequency of CPR and a lower frequency of micro-organisms (P = 0.05) was found only for the group of immediately reimplanted teeth. The presence of micro-organisms could be explained for 61 teeth. In 27 of these, blood clots containing bacteria in the apical portion of pulpal lumen indicated contamination during the extra-alveolar time, while in 34, the micro-organisms originated from plaque covered mechanical damage in the cervical part of the root surface.