Clinical and radiographic comparison of primary molars after formocresol and electrosurgical pulpotomy: a randomized clinical trial.
(10/17)
BACKGROUND: Vital pulpotomy is a single-stage procedure defined as the surgical amputation of the coronal portion of exposed vital pulp, usually as a means of preserving the vitality and function of the remaining radicular portion. OBJECTIVES: The aim of this study was to compare the clinical and radiographic success rates for electrosurgical vs formocresol pulpotomy in human primary molar teeth. SETTINGS AND DESIGN: This was a prospective, randomized clinical trial. MATERIALS AND METHODS: In this randomized clinical trial, pulpotomies were performed on 70 primary molars in children aged 5-10 years. The teeth were treated using either a conventional formocresol (35 teeth) or electrosurgical technique (35 teeth). Following the pulpotomy procedure, the teeth were evaluated for clinical and radiographic success for three, six and nine months. The teeth were evaluated for the presence of pain, abscess, fistula, mobility, internal and external resorption, and radiolucency. STATISTICAL ANALYSIS: The data were assessed with Fishers' Exact test. RESULTS: After nine months of follow-up, the clinical and radiographic success rates were 96 and 84% respectively in the electrosurgical group and 100 and 96.8% respectively in the formocresol group. There was no statistically significant difference between the success rates in the two groups ( P > 0.05). CONCLUSIONS: Our results showed the failure rates for electrosurgical pulpotomy to be equal to those for formocresol pulpotomy. Although electrosurgical pulpotomy is a nonpharmacological technique giving favorable results, it is still a preservative technique. Further studies using larger samples and longer evaluation periods are recommended. (+info)
Amelogenesis imperfecta due to a mutation of the enamelin gene: clinical case with genotype-phenotype correlations.
(11/17)
The major protein components of the enamel matrix include the most abundant amelogenin proteins as well as less plentiful proteins such as enamelin and ameloblastin. The enamel defect in amelogenesis imperfecta (Al) generally results in enamel that is too thin (hypoplastic) or too soft (hypocalcification or hypomaturation). Previous reports indicate that mutations in the human enamelin gene (ENAM) cause hypoplastic Al through autosomal-dominant inheritance patterns and patients may also exhibit an anterior open bite. Although crown resorption of unerupted teeth occurs more frequently in Al patients, this finding has not been previously associated with known ENAM mutations. The purpose of this article was to report the genotype-phenotype correlations for a 9-year, 11-month-old boy with a homozygous ENAM mutation (c.1258_1259insAG). (+info)
Tooth root resorption induced in rats by diphenylhydantoin and parathyroidectomy.
(12/17)
Changes in bone, cartilage and the dentition in animals and man following the administration of anticonvulsant drugs resemble those seen in hypoparathyroidism and pseudohypoparathyroidism. Groups of 21-day-old rats were treated with diphenylhydantoin, parathyroidectomized, or made hypocalcaemic with a calcium-deficient diet. Histological examination revealed extensive resorption of cementum and dentine in the molars of the drug-treated and parathyroidectomized rats, but not in the hypocalcaemic or control groups. Localization of injected tetracycline by fluorescence showed that the resorption affected the distal side of the tooth roots and had occurred after root formation. No changes in cementum formation on the mesial side of the roots had occurred in any of the experimental groups. These results suggest that diphenylhydantoin induces a condition similar to pseudohypoparathyroidism in which the resistance of tooth roots to resorption is reduced. (+info)
The time scale of tooth development and replacement in Xenopus laevis (Daudin).
(13/17)
One hundred and seventy two larval specimens of Xenopus laevis were reared in such a way that their rates of development (as measured by external criteria) were similar, and so the course of dental development could be examined histologically in a cross sectional study. In this way the events of tooth development were observed, and a time scale constructed for these events. The teeth took an average time of 26 days to develop, erupt and become ankylosed to the bony pedestal, after which each tooth was in a functional position for only about 7 days. Individual tooth replacement was assessed to occur about every 16 days. By comparing the number and size of the odontoblasts responsible for dentinogenesis in 18 months old adult Xenopus laevis with the odontoblasts in the larval specimens, the conclusion was drawn that, despite the larger size of the adult teeth, the time involved in their development and replacement may well be of similar duration to the smaller larval teeth. The significance of the findings for the Zahnreihen Theory is discussed. (+info)
Normal human peripheral blood mononuclear cells mobilized with granulocyte colony-stimulating factor have increased osteoclastogenic potential compared to nonmobilized blood.
(14/17)
Single-cell suspensions of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood mononuclear cells (G-PBMC) cultured in alpha minimal essential medium (alphaMEM) containing 10% fetal bovine serum formed multicellular aggregates within 24 hours. In six separate experiments, formation of aggregates appeared to be dependent on cell density per surface area, so that 5.8 +/- 1.3 aggregates formed per 1 x 10(5) cells when G-PBMC were cultured at densities greater than or equal to 1 x 10(5) cells/cm2. The frequency of aggregate formation was less than 1 per 10(5) cells when G-PBMC were cultured at densities less than 1 x 10(5) cells/cm2. Once formed, aggregates became adherent within 72 hours, and then, over the course of 21 days, released CD3/CD4/CD25-positive cells into the supernatant. This T-cell production peaked between days 7 and 14, reaching a total of 1,269 +/- 125.9 cells released per aggregate by day 21. Between days 14 and 21, the aggregates also generated macroscopic clusters of adherent mononuclear and giant multinucleated cells that stained positive for tartrate-resistant acid phosphatase (TRAP). At 4 weeks, the macroscopic foci coalesced into monolayers. Multinucleated TRAP-positive cells were distinguished from macrophage polykaryons by the absence of CD14 expression and the presence of osteoclast-specific membrane receptors for calcitonin and alphavbeta3-vitronectin. The osteoclast nature of these cells was further demonstrated by their ability to form resorption lacunae on dentine slices. Comparable osteoclast formation was not detected in cultures of normal marrow or normal nonmobilized peripheral blood. (+info)
Mononuclear odontoclast participation in tooth resorption: the distribution of nuclei in human odontoclasts.
(15/17)
Osteoclasts and odontoclasts have been considered multinucleated giant cells which resorb hard tissue by ruffled borders. Recently, the authors reported the presence of a mononuclear osteoclast and odontoclast with a ruffled border. However, the relative frequency of such cells and the distribution of the number of nuclei including mononuclear cells in them have not been elucidated. Six human deciduous teeth were used in this study. After fixation and decalcification, tartrate-resistant acid phosphatase (TRAP) activity was detected with the azo dye method, and then TRAP-positive cells were observed on resorbing areas of teeth by light microscopy. The cells for investigation were serially sectioned by semithin sections to observe the presence of resorptive lacuna and the number of nuclei. The TRAP activity was detected in both multinucleated and mononuclear odontoclasts from serial semithin sections, and 242 TRAP-positive cells which formed lacunae on dentin were investigated to determine the frequency distribution of the number of nuclei. The mean number of nuclei per cell was 5.3, and median was 4. Only 2.9% of odontoclasts were mononucleus and 93.8% had 10 or fewer nuclei. The majority of odontoclasts forming lacunae on the dentin were cells with 10 or fewer nuclei, and mononuclear odontoclasts participated in human deciduous tooth resorption together with multinucleated ones. (+info)
Ultrastructural features of odontoclasts that resorb enamel in human deciduous teeth prior to shedding.
(16/17)
Three dental hard tissues, i.e., cementum, dentin, and enamel, are resorbed by multinucleated cells referred to as "odontoclasts." These cells have morphological and functional characteristics similar to those of bone-resorbing osteoclasts. However, concerning enamel resorption, which is a process that may occur during tooth eruption, satisfactory ultrastructural data on odontoclastic resorption are still lacking. Ultrastructural and histochemical characteristics of odontoclasts resorbing enamel of human deciduous teeth prior to shedding were examined by means of light microscopy and transmission and scanning electron microscopy. Odontoclasts that that resorbed enamel were tartrate-resistant acid phosphatase (TRAP)-positive multinucleated giant cells that were essentially the same as those that resorbed dentin and cementum. Ultrastructurally, they had numerous mitochondria, lysosomes, and free polysomes in their cytoplasm. In addition, they were characteristically rich in large cytoplasmic vacuoles containing enamel crystals in the cytoplasm opposite the ruffled border. Although they extended a well-developed, ruffled border against enamel surface, a clear zone--an area typically devoid of organelles--was rarely seen in these cells. In many cases, the cells were in very close contact with the enamel surface by the peripheral part of their cytoplasm. The enamel prisms at the resorption surface contained more loosely packed and electron-lucent enamel crystals compared with those of unresorbed, intact enamel. Furthermore, numerous thin needle- or plate-like enamel crystals that were liberated from the enamel matrix were found in the extracellular channels of the ruffled border and in various-sized cytoplasmic vacuoles in their cytoplasm. The superficial layer of the enamel matrix undergoing odontoclastic resorption stained positively with toluidine blue and for TRAP activity. The results of the present study suggest that odontoclasts resorbing enamel secrete acids as well as organic components, including hydrolytic enzymes, into the resorption zone underlying their ruffled border and that they phagocytose crystals that have been liberated from the partially demineralized enamel matrix by acids, subsequently dissolving them intracellularly. (+info)