Dentosphere : World of Dentistry

# The source of mineralization for supragingival calculus is: A. Desquamated epithelial cells B. Gingival crevicular fluid C. Phosphatases formed by bacterial plaque D. Saliva The correct answer is D. Saliva. Calculus is dental plaque that has undergone mineralization. It forms on the surfaces of natural teeth and dental prostheses. Saliva is the source of mineralization for supragingival calculus, whereas the serum transudate called gingival crevicular fluid furnishes the minerals for subgingival calculus. • Supragingival calculus: is located coronal to the gingival margin. ft is usually white or pale yellow in color and is hard with a claylike consistency. It is easily removed by professional cleaning. The two most common locations for supragingival calculus to develop are the buccal surfaces of the maxillary molars and the lingual surfaces of the mandibular anterior teeth. Saliva from the parotid gland flows over the facial surfaces of the maxillary m...

# Bone consists of: A. Two-thirds organic matter and one-third inorganic matrix B. One-third organic matter and two-thirds inorganic matrix C. One-half organic matter and one-half inorganic matrix D. Two-thirds inorganic matter and one-third organic matrix The correct answer is D. Two thirds inorganic matter and one-third organic matrix. Bone consists of two-thirds inorganic matter and one-third organic matrix. The inorganic matrix is composed principally of the minerals calcium and phosphate, along with hydroxyl, carbonate, citrate, and trace amounts of other ions, such as sodium, magnesium, and fluoride. The mineral salts are in the form of hydroxyapatite crystals and constitute approximately two-thirds of the bone structure. The organic matrix consists mainly of collagen type l (90%), with small amounts of noncollagenous proteins such as osteocalcin, osteonectin, bone morphogenetic protein, phosphoproteins, and proteoglycans.

# Which one describes the boundaries that define the attached gingiva? A. From the gingival margin to the interdental groove B. From the free gingival groove to the gingival margin C. From the mucogingival junction to the free gingival groove D. From the epithelial attachment to the cementoenamel junction The correct answer is: C. From the mucogingival junction to the free gingival groove. In an adult, normal gingiva covers the alveolar bone and tooth root to a level just coronal to the CEJ. The gingiva is divided anatomically into marginal, attached, and interdental areas. - Marginal or unattached gingiva: is the terminal edge or border of the gingiva surrounding the teeth in collar- like fashion. In about 50% of cases, it is demarcated from the adjacent attached gingiva by a shallow linear depression, the free gingival groove. Usually about 1 mm wide, the marginal gingiva fonns the soft tissue wall of the gingival sulcus. - Attached gingiva: is continuo...

# Water irrigation devices (oral irrigators) have been shown to: A. Eliminate plaque B. Clean nonadherent bacteria and debris from the oral cavity more effectively than toothbrushes and mouth rinses. C. Disinfect pockets for up to 12 hours D. Prevent calculus formation The correct answer is B. Clean nonadherent bacteria and debris from the oral cavity more effectively than toothbrushes and mouth rinses. Oral irrigators for daily home use by patients work by directing a high-pressure, steady or pulsating stream of water through a nozzle to the tooth surfaces. Most often, a device with a built-in pump generates the pressure. Oral irrigators clean nonadherent bacteria and debris from the oral cavity more effectively than toothbrushes and mouth rinses. When used as adjuncts to toothbrushing, these devices can have a beneficial effect on periodontal health by reducing the accumulation of plaque and calculus and decreasing inflammation and pocket depth. Oral irri...

# In implantology, "countersinking" refers to the process of: A. Flaring or enlarging the coronal end of the osteotomy B. Reversing the engine to remove the implant C. Placing the implant in a counterclockwise rotation D. Torquing the abutment to place The correct answer is A. Flaring or enlarging the coronal end of the osteotomy. As one of the final steps in the creation of the osteotomy to receive the implant body, a special bur is activated and inserted into the occlusal end of the osteotomy in order to increase the diameter of the opening slightly or to otherwise shape it. This step is referred to as "countersinking." Countersinking the implant osteotomy is called for by some manufacturers to compensate for very dense cortical bone or to prepare the bone for a particular implant shape (e.g., a flared implant shape at the coronal end). Another of the final steps in the creation of the osteotomy is to place a threaded bur into the osteotomy so...

# Which of the following periodontal diagnoses is MOST COMMON in adults? A. Localized aggressive periodontitis B. Gingival hyperplasia C. Generalized chronic periodontitis D. Necrotizing ulcerative gingivitis E. Plaque associated gingivitis The correct answer is E. Plaque associated gingivitis. Plaque associated gingivitis (marginal gingivitis) is the MOST COMMON periodontal diagnosis. Prolonged exposure to plaque creates an inflammatory response in the gingiva, causing mild gingivitis. Gingival overgrowth can be experienced when taking: - Calcium channel blockers - Phenytoin - Dilantin - Cyclosporine Localized aggressive periodontitis is MOST COMMONLY seen younger patients and is associated with Aggregatibacter actinomycetemcomitans.

# Which of the following is the BEST method for managing a tooth with internal resorption? A. Pulpectomy and root canal therapy B. Extraction C. Svek pulpotomy D. Pulpotomy with calcium hydroxide The correct answer is A. Pulpectomy and root canal therapy. Internal resorption in a tooth requires complete pulp removal followed by a root canal procedure. Pulpotomy does not completely remove the pulp,  so the internal resorption will persist and probably progress if the pulp is not completely removed.