Idiopathic resorption of teeth. A report of three cases

External resorption of teeth is a condition typically associated with etiologic factors within the adjacent alveolar bone, such as chronic periapical or periodontal infections, neoplasms, erupting permanent teeth, orthodontic movement, or trauma to the jaws. When none of these causes are present, resorption of teeth at the cementoenamel junction has been termed "idiopathic resorption of teeth." Three cases of idiopathic resorption of teeth are reported, the literature on previous cases is reviewed, and hypotheses as to causes and a new theory are postulated regarding the possible mechanism for osteoclastic resorption of teeth.     

Stress analysis of disjunct removable partial dentures.

The (1) tooth-supported, (2) ridge-supported, and (3) tooth- and ridge-supported variations of the disjunct removable partial denture were studied. When testing loads were applied to three sites, bilaterally and unilaterally, it was found that the stresses were highest when the removable partial framework was tooth-support. No significant difference was recorded between the ridge-supported partial denture and the tooth- and ridge-supported partial framework. Further refinement of the pinsleeve mechanism may be necessary to effect better control over the distributions of the stresses.     

Waste of dental pain.

The effects of dental disease on the population are difficult to describe to the lay public in terms which that public will appreciate. An attempt has been made to quantify the impairment of the quality of life which results from uncontrolled dental disease. Studies indicated that each person could have three to four days of dental pain a year which could be equivalent to 200 million days of toothache per year in the United Kingdom. Only 15 per cent of those who had toothache did seek dental advice for it. This represented a waste and an impairment in the quality of life. It is proposed that estimates of days of dental pain could prove an index of the quality of life of a population.     

The biochemical growth and development of the palate, maxilla, mandible and tongue in the New Zealand white rabbit

Seventy-two female New Zealand white rabbits were divided into six groups and killed with Nembutal at 17.0, 17.5, 18.0, 18.5, 19.0 and 19.5 days postconception. The foetuses were removed; the palates, maxilla, mandibles and tongues were dissected from each foetus, weighed and pooled; DNA, RNA and protein were determined in each pooled sample. The results showed three distinct patterns of development. The mandible and maxilla showed similar developmental patterns, while the palate and tongue each showed their own distinct pattern. The palate showed a remarkable rise in protein/DNA at day 18.0, the time corresponding to palatal closure in our rabbits. Further such studies may elucidate the role that relative growth rates of these tissues plays in the aetiology of cleft palate.     

Isotypic antibody response to plaque anaerobes in periodontal disease

BACKGROUND: It has been suggested that locally produced immunoglobulin (Ig)A could be more protective than IgG and that there could be a relationship between crevicular fluid-specific IgA levels and the onset of periodontal disease. This study was designed to investigate this hypothesis regarding specific immune responses towards 4 plaque anaerobes in gingival crevicular fluid and saliva from patients with periodontopathies and controls. METHODS: Gingival crevicular fluid (GCF) and whole saliva were collected from 35 adults with periodontitis and 24 periodontally healthy adults (controls). Antigens were extracted from Actinomyces actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum and used to set up specific enzyme-linked immunosorbent assay (ELISA) tests to assess IgA and IgG levels to these microorganisms in the fluids collected. RESULTS: The crevicular fluid of periodontitis patients contained significantly higher levels of IgG to the 4 microorganisms tested than that of controls (P < 10(-6) for all comparisons). IgA levels to the 4 bacteria were statistically significantly much higher in control crevicular fluid (P < 10(-7) for all comparisons). Controls also had statistically significantly higher levels of specific salivary IgA than patients (P < 0.02 for all comparisons). CONCLUSIONS: These data support the potentially protective role of specific IgA directed to oral microorganisms involved in the onset and development of periodontal disease.     

Three-dimensional changes in the condyle during development of an asymmetrical mandible in a rat: a microcomputed tomography study.

A rapidly growing postnatal animal model was used to study changes in the calcified tissue of the mandibular condyle during altered muscle function. A maxillary occlusal splint was designed to shift the mandible laterally (left) during closure. Groups of 5 Wistar rats were killed at 5, 9, 15, 21, 30, and 40 weeks (n = 30), with an equal number of controls. The experimental animals developed shorter, asymmetrical mandibles compared with the control animals. The left condyle became larger and thicker than the right condyle. Microcomputed tomography assessment of the left and right condylar trabecular bone indicated that both had less bone volume than the control condyle. The right masseter muscle significantly lost fiber size and type IIA oxidative fibers, suggesting that the right masseter muscle was used with less tension development. In contrast, the left masseter maintained its fiber size and was similar to the control masseter fiber diameters. Comparison in the sequence of changes indicated that the morphologic changes occurred first in the ramus (age, 5 weeks), before the corpus (age, 15 weeks), and before changes in masseter fiber size and composition (age, 9 weeks). This study showed that both the mandible and the condyle modified their shape and size, as well as the trabecular bone of the condyle, during shifting of the mandible to one side as it closed.     

Repair of alveolar clefts with recombinant human bone morphogenetic protein (rhBMP-2) in patients with clefts

This article demonstrates the feasibility of using recombinant human bone morphogenetic protein (rhBMP-2) as a substitute for autogenous iliac crest bone for repair of congenital facial clefts in humans. In this series, 50 cleft sites were repaired in 43 patients using rhBMP-2 without the use of autogenous graft tissue. Successful osseous union was achieved in 49 of the 50 sites. In one patient, the graft failed to consolidate. Severe clefts were managed by combining distraction osteogenesis and rhBMP-2. Eliminating the need to harvest autogenous iliac crest bone resulted in substantial decrease in morbidity. The constructed alveolus performed clinically as normal bone and responded to natural tooth eruption and orthodontic movement. Histology of the tissue constructed showed normal, vital bone. Although additional investigation is warranted to determine the optimum protocol for the use of this material in alveolar cleft repair, the technique should be considered as a viable treatment option in cases in which avoiding iliac crest harvesting is desirable.