Leif Blomlöf

Tooth ankylosis. Clinical, radiographic and histological assessments.

Ankylosis is a serious condition for the affected teeth as such teeth form part of the remodelling process of the alveolar bone and are therefore progressively resorbed. There are, however, very few clinical studies on tooth ankylosis and the reason for this may be due to the difficulties that are encountered in the diagnosis of minor areas of ankylosis. In the present study, the radiographs, percussion sound and mobility of experimentally extracted and replanted monkey incisors were compared with a morphometric histological study of ankylosis. Ankylotic areas were evident radiographically when the ankylosis was located on the proximal surfaces of the root, but were not evident when the ankylosis occurred on the lingual and labial surfaces. The percussion sound was dull and the mobility normal in all non-ankylotic teeth as well as in those teeth which histologically demonstrated ankylosis on less than 10% of the root surface. When the ankylosis affected 10-20% of the root surface, 2 out of 4 teeth changed their percussion sound from dull to high and these teeth no longer possessed normal mobility. When more than 20% of the root surface was affected with ankylosis, the percussion sound was characteristically high in all teeth and no mobility was present.

Storage of Experimentally Avulsed Teeth in Milk Prior to Replantation

Extracted monkey teeth were endodontically treated, stored in milk or saliva for two or six h, and then replanted. Periodontal conditions were evaluated after eight wk. Teeth that had been stored for two or six h in milk or for two h in saliva showed periodontal healing almost as good as that of immediately replanted teeth. Teeth that had been kept in saliva for six h or bench-dried for one h showed extensive replacement resorption. Milk may thus be recommended as a storage medium for ex-articulated teeth prior to replantation in cases when immediate replantation is not possible.

Influence of osmolality and composition of some storage media on human periodontal ligament cells.

The effect of media with different osmolalities and compositions on cell viability and integrity of the cell membrane has been studied. Physiologic media, such as milk, saline and physiologic sucrose solution, preserved cell viability and membrane morphology equally well. The cell membrane of cells stored in saliva was more extensively damaged than the cell membrane of cells stored in a sucrose solution with an hypotonic osmolality similar to saliva. Thus a hypotonic osmolality seemed to potentiate the damaging effect of an unfavourable composition or a bacterial contamination of the storage media.

Periodontal Healing of Replanted Monkey Teeth Prevented from Drying

Root resorption of replanted teeth is dependent on the duration of the extra-alveolar period and on the storage environment. In the present investigation the significance of preserving the humidity of the periodontal ligament (PDL) during the extra-alveolar period was tested on isolated PDL cells and on replanted monkey teeth. The isolated PDL cells were tested with respect to cell viability (trypan blue exclusion test) and to cell recovery (number of cells after additional cultivation). About 70% of the cells were viable and 44% recovered after 1 h in a humid atmosphere. Practically no cells were viable or recovered after 1 h of drying. Replanted teeth that had been wrapped in plastic foil for 1 h before replantation showed no more resorption than immediately replanted teeth. This is in contrast to teeth dried in air for 1 h before replantation. They showed extensive root resorption on almost all root surfaces. Thus, prevention of evaporation of tissue fluid from the PDL must be considered a primary goal if the tooth cannot be replanted immediately.

Occurrence and appearance of cementum hypoplasias in localized and generalized juvenile periodontitis

The occurrence and appearance of cementum hypoplasias have been studied on teeth affected by juvenile periodontitis. Scanning electron microscopy showed the presence of cementum hypoplasias on the root surface of all extracted first molars and one incisor from nine patients with localized juvenile periodontitis and on most extracted teeth from two patients with generalized juvenile periodontitis. No hypoplasias were found on the extracted third molars. The alveolar bone loss in these patients seemed to be correlated to the frequency and extension of the hypoplastic areas in the associated teeth. The distribution of the teeth affected by localized juvenile periodontitis showed a symmetric distribution in the jaws. The patients with generalized juvenile periodontitis showed considerable deposits of dental calculus and wide areas of root resorption. The disturbance of cementum formation may have been caused by hereditary systemic factors, which subside with increasing age of the patient. The clinical appearance of juvenile periodontitis may therefore be influenced by the age at onset, the duration, and the frequency of such systemic factors, giving rise to a localized form and a more generalized form. One such factor may be a varying degree of hypophosphatasia.

A clinical and radiographic evaluation of cultivated and autotransplanted human teeth

A vital periodontal membrane (PDM) is of ultimate importance for a successful periodontal healing of auto-transplanted teeth. It has been suggested that a damaged PDM may heal during an intermediate tissue culture period. In the present study, 26 canines, bicuspids and third molars were surgically removed and cultivated in a modified Eagles medium for 3 to 17 weeks. The teeth were then transplanted to their new positions. 11 out of 18 (61%) transplanted teeth with complete root formation and 7 out of 8 (88%) transplanted teeth with incomplete root formation healed with an apparently normal periodontal ligament. 5 teeth, all canines, became ankylotic. Tissue cultivation of teeth to be transplanted resulted in approximately the same healing rate as has been reported for autotransplanted teeth without the tissue culture procedure.

Validation of an Algorithm for Chronic Periodontitis Risk Assessment and Prognostication: Analysis of an Inflammatory Reactivity Test and Selected Risk Predictors

BACKGROUND Patients with severe forms of chronic periodontitis present with varying degrees of decreased inflammatory reactivity. A previously reported algorithm for chronic periodontitis risk assessment and prognostication is based on the analysis of some 20 risk predictors. One of these predictors is a skin provocation test that assesses the individual patients reactivity to a lipid A challenge. The aim of this report was to analyze results from validation data for the algorithm with respect to the contribution of results of the skin provocation test as a risk predictor for the progression of chronic periodontitis and to compare these results with the contribution from other predictors, namely smoking, angular bony destruction, furcation involvement, abutment teeth, and endodontic pathology. METHODS Data from a previously reported clinical validation sample were used for the analysis, including the calculation of quality measures and explanatory values using different types of regression analysis and non-parametric testing. RESULTS Smoking, endodontic pathology, abutment teeth, angular bony destruction, and furcation involvement presented with individual explanatory values for periodontitis progression between 4% and 13% and highly significant parameter estimates. Explanatory values for the results of the skin provocation test ranged between 2.6% and 5.1% depending on the disease severity group, with a positive predictive value of 82% for the identification of high-risk patients. CONCLUSION The skin provocation test provided a clinically significant contribution to the quality of analysis with the periodontitis risk and prognostication algorithm, in particular in the selection of high-risk patients for in-depth individual tooth analysis.

Cultivation of fibroblasts on human teeth. Ultrastructural observations of cells cultivated in multilayers.

The periodontal ligament in a traumatically lost tooth is often destroyed due to drying. In attempts to restore the periodontal ligament, a technique has been worked out for using gingival biopsies as an alternative cell source. A biopsy from the attached gingiva was set up for tissue cultivation. After the establishment of a pure fibroblast culture, cells were repeatedly added to the root surfaces of 12 human teeth from which the cells and the original periodontal ligament had been removed. The teeth were examined in the transmission electron microscope. The root surface of specimens from all 12 teeth was covered with a pelliclelike material arranged in a layered pattern. The cells frequently appeared in multilayers on top of the pellicle. The cells were flattened and appeared elongated in sections. Areas of close proximity between cells and the pellicular material were seen and were interpreted as adherence junctions. The possibility that these multicellular arrangements can replace the periodontal ligament in transplantation has to be further investigated.

Use of acrylate root reproductions in replantation and transplantation of teeth

A method to prepare and test the fitness of the alveolus in the jaw before transplantation of teeth is carried out. An impacted canine from a 30-year-old woman was extracted and stored in tissue culture for 3 weeks. The tooth was then transferred to a semisolid tissue culture medium for preparing an artificial alveolus. Methylacrylate was then poured into the alvelous and was left to solidify at room temperature. Thereafter the root model was removed from the medium and a screw was fixed in the upper part. This root model was used in testing the fitness of the prepared alveolus before the root was transplanted. The advantage of the technique is that the reproduction of the root could replace the transplant during the fitting procedure to avoid damage to the periodontal membrane.