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Showing posts from April, 2017

Restoration of endodontically treated teeth

Typically, root canal treatment is initiated because of deep caries or trauma, both of which often result in extensive loss of tooth structure. Additional tooth tissue is removed for endodontic access, cleaning and shaping of the root canal, and post space preparation, further reducing the structural integrity of the tooth and decreasing its resistance to fracture.   At one time it was believed that endodontically treated teeth are inherently more brittle and susceptible to fracture.   Subsequent research has shown that the dentin of endodontically treated teeth exhibits mechanical properties equivalent to that of untreated teeth. It has also been proposed that a portion of the sensory feedback mechanism is lost when the neurovascular tissue has been removed from the tooth in the course of endodontic therapy. Clinically, this means that the patient can inadvertently bite with more force on an endodontically treated tooth than on a vital tooth because of the impaired ...

Cracks, cracks, cracks

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Today I had a case that taught me not to focus on the obvious cause of pain. A patient came in complaining of pain on the 25. the 24 had previously been filled by another dentist and I assume it must have been a carious exposure. Checking the xrays before the patient arrived I settled on the 24 as the probably cause of pain. She presented and was very sure that it was the 25 painful to hot and cold. There was an MOD amalgam in the 25 that appeared sound. I still thought it was the 24... Cold test was very painful for both but more so for the 25. The curiosity was that there was an exaggerated response to pain on the 25 as it appeared sound. I was very ready to extract the 24, so much so that the needle was right near the tooth for LA. I decided to test the teeth once more and again a more exaggerated response from the 25. Still unsure if the patient was confused, I did a heat test for the first time. Rubber dam isolation of the 25 and washing of the tooth with warm water from a monoje...

Ankylosed and submerged primary molar

In the absence of ankylosis, primary molars without permanent successors may function for many years before exfoliation, preserving alveolar bone height and width . If a periapical radiograph shows flat bone levels between the submerged primary molar and adjacent teeth, the tooth may be maintained, preserving alveolar bone until facial growth is complete, and an implant can be placed. In this case, the mesial and distal surfaces of the mandibular primary molar can be disked to achieve premolar width. The mesiodistal width at the cementoenamel junction measured on a bitewing or periapical radiograph provides a good guideline for the amount of reduction, as does comparison to the contralateral side. The average width of the mandibular second premolar is  7.5 mm. Seven millimeters has also been recommended as the width to attain. This size can be marked with a pencil or marking pen on the occlusal of the primary molar to provide a guide for reduction. After administration of local ane...

Local Anesthetic Considerations When Treating Patients with Oral Infections

Products of inflammation lower the surrounding tissue pH (e.g., purulent exudates have a pH of 5.5-5.6). At this more acidic pH, the numbers of base molecules necessary for passage of the anesthetic into the nerve membrane may be significantly reduced. Inflammatory exudates may also enhance nerve conduction action potentials, making blockage of sensory nerve impulses more difficult. In addition, blood vessels in the area of inflammation may be dilated, leading to a more rapid uptake of the anesthetic agent from the area of injection. These changes can lead to delays in onsets of anesthesia, inadequate depths of anesthesia, and the potential for local anesthetic blood levels to be elevated.  Needle tract  infection  is a potential complication of injection into  infected  tissues. Although penetration into  infected  tissues can be avoided by using more distant regional nerve blocks, whenever there is a possibility of a needle having passed through...