Dentosphere : World of Dentistry

 # Compound odontoma shows on a radiograph as: A. Supernumerary teeth B. Radiolucent and radiopaque areas C. Mass of calcified areas D. Distinguishable tooth like structures The correct answer is D. Distinguishable tooth like structures. The radiographic appearance of the odontoma is characteristic. Since most odontomas are clinically asymptomatic and are discovered by routine radiographic examination, the dentist should be familiar with their appearance. They are often situated between the roots of teeth and appear either as an irregular mass of calcified material surrounded by a narrow radiolucent band with a smooth outer periphery, or as a variable number of tooth like structures with the same peripheral outline. This latter type of odontoma may contain only a few structures resembling teeth, or it may contain several dozen. Both forms of odontoma are frequently associated with unerupted teeth. It is of interest that the majority of odontomas in the anterior segments of the jaws...

 # APC gene is mutated in: A. Hereditary intestinal polyposis syndrome B. Gardner’s syndrome C. Gorham stout syndrome D. Caffey Silverman Syndrome The correct answer is B. Gardner's syndrome. Gardner syndrome, inherited as an autosomal-dominant disorder, is characterized by intestinal polyposis, multiple osteomas, fibromas of the skin, epidermal and trichilemmal cysts, impacted permanent and supernumerary teeth, and odontomas. The genetic defect is found in a small region on the long arm of chromosome 5 (5q21), where the familial adenomatous polyposis (APC) gene resides. Most patients with Gardner’s syndrome do not exhibit the complete spectrum of clinical disease expression. Osteomas associated with this syndrome may be found in the jaws (especially the mandibular angle) and in facial and long bones. Intestinal polyps associated with Gardner syndrome are commonly located in the colon and rectum. Significantly, these polyps, found microscopically to be adenomas, exhibit a very high...

 # Obstructive sleep apnea syndrome (OSAS) often results in all of the following except:  A. Excessive daytime sleepiness  B. Aggressive behavior  C. Personality changes  D. Depression  The correct answer is B. Aggressive behavior. Signs and symptoms Generally, symptoms of OSA begin insidiously and are often present for years before the patient is referred for evaluation. Nocturnal symptoms may include the following: Snoring, usually loud, habitual, and bothersome to others Witnessed apneas, which often interrupt the snoring and end with a snort Gasping and choking sensations that arouse the patient from sleep, though in a very low proportion relative to the number of apneas they experience Nocturia Insomnia; restless sleep, with patients often experiencing frequent arousals and tossing or turning during the night Daytime symptoms may include the following: Nonrestorative sleep (ie, “waking up as tired as when they went to bed”) Morning headache, dry or sor...

 # The most common mandibular surgical osteotomy to advance the mandible is ____.  A. Le Fort I osteotomy  B. Segmental maxillary osteotomy  C. Bilateral sagittal split osteotomy  D. Intraoral vertical ramus osteotomy  The correct answer is C. Bilateral sagittal split osteotomy. Bilateral sagittal split osteotomy (BSSO) is one of the most commonly performed and versatile mandibular procedures. It can be used for backward or forward correction of the mandible in isolation or in combination with a maxillary osteotomy. It is usually performed while the patient is under general anaesthesia. It was originally described by Trauner and Obwegeser in 1957. The procedure has since undergone numerous modifications, including those by Dalpont, Hunsuck, Bell and Epker. Even when there are large advancements, bone grafting is rarely required because of the long bony interface between the two fragments. Indications for BSSO include mandibular advancement, setback and...

 # Distraction osteogenesis is preferred over a traditional osteotomy:  A. When a large advancement is needed  B. When a small advancement is needed  C. When exacted interdigitation of the occlusion is needed  D. When the treatment needs to be done in a very short period of time  The correct answer is A.  When a large advancement is needed. Distraction osteogenesis is preferred over traditional osteotomies when large skeletal movements are required and the associated soft tissue cannot adapt to the acute changes and stretching that results. Larger movements may be at increased risk of some relapse; this is particularly true in a patient with a cleft palate, where there is significant soft tissue scarring from previous surgeries.

 # At which of the following locations are perikymata usually found? a. Cervix of the crown. b. Apex of the root. c. Cusp tips. d. Deposited throughout the crown. The correct answer is A. Cervix of the crown. Perikymata are transverse, wave-like grooves, believed to be the external manifestations of the striae of Retzius. They are continuous around a tooth and usually lie parallel to each other and to the cementoenamel junction. Ordinarily there are about 30 perikymata per millimeter in the region of the cementoenamel junction, and their concentration gradually decreases to about 10 per millimeter near the occlusal or incisal edge of a surface. Their course usually is fairly regular, but in the cervical region it may be quite irregular. The terms perikymata and imbrication lines are used without distinction to the surface structures of ridges or grooves. To avoid confusion in the usage of these terms it has been suggested that the terms perikymata or imbrication lines be suffixed b...

 # Bones that are small, irregularly shaped, and found along sutures are called  a. Parietal.  b. Wormian.  c. Temporal.  d. Zygomatic.  The correct answer is B. Wormian bone. Wormian bones, also known as intrasutural bones or sutural bones, are extra bone pieces that can occur within a suture (joint) in the skull. These are irregular isolated bones that can appear in addition to the usual centres of ossification of the skull and, although unusual, are not rare. They occur most frequently in the course of the lambdoid suture, which is more tortuous than other sutures. They are also occasionally seen within the sagittal and coronal sutures. A large wormian bone at lambda is often called an Inca bone (Os Incae), due to the relatively high frequency of occurrence in Peruvian mummies. Another specific Wormian bone, the pterion ossicle, sometimes exists between the sphenoidal angle of the parietal bone and the great wing of the sphenoid bone. They tend to vary i...