PubMed · 14826528
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D F TOBIN. 1951. Silicate cements.. https://pubmed.ncbi.nlm.nih.gov/14826528/
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OBJECTIVE: The aim of the present study was to assess the removal of root substance with the Vector-system depending on different irrigation fluids and to compare the results with conventional methods for root debridement. MATERIAL AND METHODS: Forty extracted human teeth were treated using four different methods: Vector-system with polishing fluid and metal curette (VP), Vector-system with abrasive fluid and metal curette (VA), conventional ultrasonic system (U) with insert tip "P" and hand instrument. Treatment of the calculus-free root surfaces was carried out for a total of 12 min. using an artificial periodontal pocket. At intervals of 120 s, the removal of dental hard tissues was assessed using a three-dimensional (3D) laser scanning device and the Match 3D software with an accuracy of 0.00001 mm(3). RESULTS: No difference in the removal of root substance with the hand instrument (0.0055 mm(3)/s) and the Vector-system using the abrasive fluid (0.0044 mm(3)/s) could be observed (p=0.51). Using these two systems, a larger amount of root substance (p<0.05) was removed compared with the other methods (U: 0.0023 mm(3)/s, VP: 0.0022 mm(3)/s), which did not differ from each other (p=0.76). CONCLUSIONS: The present study indicates that the Vector-system in combination with polishing fluid or conventional ultrasonics might be used for root debridement without extensive root substance removal.
Prior to the shedding of human deciduous teeth, odontoclastic resorption takes place at the pulpal surface of the coronal dentin, and this resorption occasionally extends coronally from the dentinoenamel junction into the enamel. After the end of resorption, however, the resorbed enamel surface is repaired by the deposition of a cementum-like tissue. Using this phenomenon as an observation model, in this study we examined the sequence of cellular and extracellular/matrix events involved in the enamel resorption repair by light and electron microscopy. As the odontoclast terminated its resorption activity, it detached from the resorbed enamel surface; thereafter, numerous mononuclear cells were observed along the resorbed enamel surface. Most of these mononuclear cells made close contact with the resorbed enamel surface, and coated pits or patches were observed on their plasma membrane facing this surface. Furthermore, they frequently contained thin needle- or plate-like enamel crystals in their cytoplasmic vacuoles as well as secondary lysozomes. Following the disappearance of these monononuclear cells, the resorbed enamel surface now displayed a thin coat of organic matrix. Ultrastructurally, this organic layer was composed of a reticular and/or granular organic matrix, but contained no collagen fibrils. Energy-dispersive X-ray microanalysis of this thin organic layer in undecalcified sections revealed small spectral peaks of Ca and P. Cementum-like tissue initially formed along this thin organic layer, increased in width, and appeared to undergo mineralization as time progressed. The results of our observations demonstrate that regardless of type of matrix of dental hard tissues, tooth repair may be coupled to tooth resorption, and suggest that mononuclear cells and an organic thin layer found on the previously resorbed enamel surface may play an important role in the repair process initiated after resorption of the enamel.
Concrescence represents an uncommon developmental anomaly in which juxtaposed teeth are united in the cementum but not in the dentin. The incidence of concrescent teeth is reported to be highest in the posterior maxilla. The presence of concrescent teeth may influence surgical procedures as well as periodontal, endodontic and even orthodontic diagnoses and treatment. Therefore, consideration should be given to the possible occurrence, recognition, and implications of this anomaly in diagnosis and treatment planning. The purpose of this article is to report a case of concrescence between an impacted third molar and an erupted second molar that was identified postextraction.