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The sunray or sunburst appearance on radiographs is a classic sign of osteogenic sarcoma (osteosarcoma), resulting from the tumor's aggressive periosteal reaction. The tumor causes new bone formation perpendicular to the cortex, producing radiating spicules resembling rays of the sun. This pattern indicates rapid and invasive bone growth typical of malignant osteoblastic activity. Other conditions like osteomyelitis or fibrous dysplasia do not typically produce this distinct periosteal reaction. Recognizing this radiographic feature is crucial for early diagnosis and appropriate surgical planning.

Reference: Orthopaedics: Principles and Their Applications, Rockwood & Green, 7th Edition.
Acute apical periodontitis is an inflammatory condition of the periodontal ligament at the tooth apex, often caused by bacterial infection from the pulp. This inflammation can lead to a localized immune response, resulting in regional lymphadenopathy due to the drainage of infectious agents and inflammatory mediators into the regional lymph nodes. The swelling and tenderness of these lymph nodes are signs of the body's attempt to contain the infection. Recognizing regional lymphadenopathy is important for assessing the spread and severity of the infection and guiding appropriate treatment.

Reference: Oral Pathology, Neville et al., 4th Edition.
Gutta-percha points are primarily used in endodontics for root canal obturation. The largest component of these points is zinc oxide, which provides the bulk and rigidity necessary for the point to maintain its shape within the root canal. Zinc oxide also offers radiopacity and antimicrobial properties, aiding in the effective sealing and prevention of reinfection. The gutta-percha resin, although essential for flexibility and thermoplasticity, constitutes a smaller proportion. The dominance of zinc oxide ensures the point's mechanical stability during obturation procedures.

Reference: Endodontics: Principles and Practice, Mahmoud Torabinejad, Edition 6.
Under normal circumstances, the margin of a dental restoration should be placed supragingival because it allows for easier cleaning, better periodontal health, and improved longevity of both the restoration and surrounding tissues. Supragingival margins minimize plaque accumulation and reduce gingival irritation. They also facilitate accurate impression taking and better visual access during preparation and restoration. Subgingival margins are reserved for specific indications such as esthetics, caries extension, or restoration retention when necessary. Thus, maintaining the margin supragingivally whenever possible promotes overall oral health and clinical success.

Reference: Sturdevant's Art and Science of Operative Dentistry, Roberson, 7th Edition.
For gold inlays, the gingival margin should ideally be a bevel because it provides a better seal and adaptation of the gold restoration to the tooth structure. The bevel increases the surface area for bonding and allows for a that minimizes marginal leakage and plaque accumulation. Additionally, a beveled margin helps in distributing occlusal forces evenly and facilitates easier finishing and polishing. This results in improved longevity and aesthetics of the restoration.

Reference: Sturdevant's Art and Science of Operative Dentistry, Roberson, 7th Edition.
The minimum occlusal clearance for an all-metal crown is 1-1.5 mm to provide sufficient space for the metal alloy thickness while maintaining crown strength and proper occlusion. Less than 1 mm clearance risks inadequate crown thickness, leading to fracture or distortion during function. More clearance than necessary may cause excessive tooth structure removal, compromising tooth integrity. This dimension ensures a durable restoration with optimal fit and occlusal harmony, critical for longevity and patient comfort.

Reference: Sturdevant's Art and Science of Operative Dentistry, Roberson, 6th Edition.
The rubber dam sheet is an essential accessory used in dental procedures to isolate the operative field, providing a clean and dry working area. It helps in preventing contamination from saliva and blood, improving visibility and access to the tooth being treated. The rubber dam also protects the patient from aspirating or swallowing debris and dental materials. Unlike cotton rolls, gauze pads, or saliva ejectors that assist in moisture control, the rubber dam is the primary tool for complete isolation of one or multiple teeth. This isolation enhances the effectiveness and safety of restorative, endodontic, and surgical treatments.Reference: Principles and Practice of Operative Dentistry, Monaghan, 3rd Edition.
Bleaching of vital teeth is contraindicated in sensitive teeth because bleaching agents like hydrogen peroxide can exacerbate tooth sensitivity by penetrating enamel and dentin, irritating the pulp. This can lead to discomfort, pain, and potential pulp inflammation. In contrast, discolored teeth, mild fluorosis, and tetracycline staining are common indications for bleaching. Managing sensitivity before or instead of bleaching avoids patient discomfort and adverse outcomes. Therefore, sensitivity is a critical factor that dictates the appropriateness of vital bleaching.

Reference: Principles and Practice of Operative Dentistry, Satinder Dhawan, 3rd Edition.
The serrated parallel post provides the greatest retention due to its increased surface area and mechanical interlocking within the root canal. Unlike tapered posts, parallel posts maintain uniform thickness, preventing stress concentration and maximizing frictional resistance. The serrations further enhance retention by creating micro-retentions without excessive dentin removal. This combination optimizes post stability and minimizes risk of post dislodgement in endodontically treated teeth.

Reference: Stewart’s Clinical Removable Partial Prosthodontics, Stewart, 4th Edition.

ফ্রিতে ২ লাখ প্রশ্নের টপিক, সাব-টপিক ভিত্তিক ও ১০০০+ জব শুলুশন্স বিস্তারিতে ব্যাখ্যাসহ পড়তে ও আপনার পড়ার ট্র্যাকিং রাখতে সাইটে লগইন করুন।

লগইন করুন
Arthrography is most useful in diagnosing internal derangement of the TMJ because it allows for direct visualization of the articular disc position and mobility. This imaging technique can identify disc displacement, perforation, or adhesions within the joint, which are hallmarks of internal derangement. It provides dynamic assessment during mouth opening and closing, aiding in precise diagnosis and treatment planning. Arthrography is less effective in bony changes seen in osteoarthritis, ankylosis, or fractures, where other imaging modalities like CT or MRI are preferred.

Reference: Oral & Maxillofacial Pathology, Neville et al., 4th Edition.
Cracked tooth syndrome involves a partial fracture of the tooth that extends into the dentin and sometimes the pulp, leading to bacterial ingress and inflammation. This results in pulpal irritation and pulpitis, causing pain often triggered by biting or temperature changes. Unlike fluorosis, hypercementosis, or amelogenesis imperfecta, which primarily affect tooth structure or appearance, cracked tooth syndrome directly compromises pulp integrity. Early diagnosis and management are crucial to prevent progression to irreversible pulpitis or necrosis.

Reference: Oral Pathology, Neville et al., 4th Edition.
The standard working length of a reamer in endodontics is 16 mm because it corresponds to the average length needed to adequately prepare and clean the root canal system without damaging periapical tissues. This length allows for efficient removal of dentin while maintaining control within the canal. Using a reamer of 16 mm helps in reaching the apical third of most anterior and premolar teeth, ensuring thorough debridement. Longer or shorter reamers may compromise cleaning efficacy or cause procedural errors. Therefore, the 16 mm length balances accessibility and safety during root canal preparation.

Reference: Endodontics: Principles and Practice, Mahmoud Torabinejad, Edition 5.
The cavosurface margin of an inlay preparation should be bevelled to increase the surface area for the restorative material to bond effectively. This improves the marginal seal, reduces microleakage, and enhances the mechanical retention of the inlay. Additionally, beveling helps in distributing occlusal forces more evenly, which minimizes the risk of fracture at the margin. A bevel also facilitates a smoother transition between the tooth and restoration, improving esthetic outcomes and longevity of the restoration.

Reference: Principles and Practice of Operative Dentistry, Clifford M. Sturdevant, 5th Edition.
In a Class III cavity preparation, the axial wall forms the base because it represents the surface of the tooth parallel to the long axis, providing a stable and supportive foundation for the restoration. The axial wall is critical in maintaining the structural integrity of the tooth and ensures adequate thickness of restorative material for strength. Unlike the pulpal or gingival walls, which serve as cavity boundaries, the axial wall directly supports the restorative base. Proper formation of the axial wall prevents overextension and protects the pulp from excessive removal.

Reference: Sturdevant's Art and Science of Operative Dentistry, James B. Summit, et al., 7th Edition.
The earliest clinical sign of dental caries is a chalky white area on the tooth, which represents demineralization of the enamel. This white spot lesion occurs before the enamel surface breaks down and cavitation develops. It indicates subsurface mineral loss while the surface remains intact, making it a reversible stage if proper remineralization therapy is applied. Recognizing this non-cavitated lesion is crucial for early intervention to prevent progression to cavity formation, discoloration, or tooth mobility. Thus, the chalky white spot is the primary clinical indicator of initial caries activity.

Reference: Principles of Operative Dentistry, Stanely F. Malamed, 13th Edition.
Vertical root fractures in endodontically treated teeth most commonly occur along the mesiodistal root surface of mandibular molars because this area is narrower and subjected to higher occlusal forces, especially during mastication. The root anatomy, combined with extensive dentin removal during canal preparation, predisposes these roots to fracture vertically in the mesiodistal plane. Additionally, the presence of multiple canals and thinner dentinal walls in mandibular molars increase susceptibility. Recognizing this common fracture location is crucial for accurate diagnosis and management of vertical root fractures.

Reference: Pathways of the Pulp, 12th Edition.
A chronic periapical abscess typically presents as a well-circumscribed radiolucent area at the root apex on radiographs due to localized bone resorption from prolonged infection. This radiolucency reflects the presence of a granulomatous or cystic lesion formed as the body attempts to contain the infection. Unlike ill-defined radiopacities or diffuse changes, the clear margins indicate a chronic process where bone destruction has stabilized. Identification of this radiolucency is crucial for diagnosis and guides endodontic treatment or surgical intervention. Early recognition helps prevent further bone loss and potential spread of infection.

Reference: Oral Radiology, 6th Edition.
The placement of dental amalgam restorations involves exposure to mercury, which can trigger severe allergic reactions in sensitized individuals. A history of mercury allergy is an absolute contraindication because even minimal exposure can cause systemic and localized hypersensitivity responses, potentially leading to significant morbidity. Alternatives such as composite or glass ionomer restorations should be used in these cases. Other listed conditions do not pose a systemic or immunologic risk that contraindicates amalgam placement. Therefore, patient safety mandates avoiding amalgam in those with mercury allergies.

Reference: Sturdevant’s Art and Science of Operative Dentistry, 7th Edition.
Beveling enamel margins during composite resin cavity preparation primarily serves to increase the enamel surface area available for bonding. This enlarged surface enhances the micromechanical retention of the resin by exposing enamel rods at a favorable angle for acid etching and resin infiltration. As a result, the bond strength is significantly improved, leading to better retention and longevity of the restoration. Additionally, beveling creates a smoother transition between tooth and restoration, improving esthetics. However, the main clinical benefit remains the enhancement of the bonding surface area, crucial for the success of adhesive restorative procedures.
Reference: Sturdevant's Art and Science of Operative Dentistry, 7th Edition.

ফ্রিতে ২ লাখ প্রশ্নের টপিক, সাব-টপিক ভিত্তিক ও ১০০০+ জব শুলুশন্স বিস্তারিতে ব্যাখ্যাসহ পড়তে ও আপনার পড়ার ট্র্যাকিং রাখতে সাইটে লগইন করুন।

লগইন করুন
The most significant characteristic of glass ionomer cement (GIC) as a restorative material is its fluoride release. This property provides a continuous local supply of fluoride ions, which helps in inhibiting secondary caries and promoting remineralization of adjacent tooth structure. While adhesion to dental tissues is important, the anticariogenic effect from fluoride release enhances the longevity and preventive capabilities of the restoration. Other characteristics, such as compressive strength and aesthetics, are secondary in comparison to its role in caries prevention. Thus, fluoride release is crucial for both restorative function and preventive dental health.

Reference: Sturdevant’s Art and Science of Operative Dentistry, 7th Edition.
Microleakage is the most frequent cause of failure in composite resin restorations because it leads to the infiltration of bacteria and oral fluids at the tooth-restoration interface. This compromises the seal, causing sensitivity, staining, and eventual secondary caries. Additionally, microleakage results from polymerization shrinkage, which creates gaps and stresses at adhesive bonds. Proper adhesive techniques and incremental layering help minimize microleakage but cannot eliminate it completely, making it the primary clinical challenge in composite longevity.

Reference: Sturdevant's Art and Science of Operative Dentistry, 7th Edition.
The Bitewing radiograph is most effective for identifying interproximal caries in posterior teeth because it provides a clear, detailed view of the crowns of the upper and lower teeth simultaneously, especially the areas between teeth where caries commonly develop. It allows for optimal visualization of contact points and enamel-dentin junctions without superimposition of other anatomical structures. This makes it superior to periapical, occlusal, or panoramic radiographs, which either show limited interproximal detail or lack sufficient resolution. Bitewings are the standard radiographic technique for detecting early and hidden interproximal lesions in posterior dentition with high diagnostic accuracy.

Reference: White and Pharoah, Oral Radiology: Principles and Interpretation, 8th Edition.
The primary benefit of using rubber dam isolation during dental restorative treatments is improved moisture control. Maintaining a dry operative field is crucial for the adhesion and longevity of restorative materials such as composites. The rubber dam effectively prevents saliva, blood, and other fluids from contaminating the treatment area, ensuring optimal bonding conditions. Additionally, it aids in reducing bacterial contamination and improves overall treatment quality. While other benefits exist, control of moisture is the key clinical advantage that justifies rubber dam use in restorative procedures.

Reference: Sturdevant's Art and Science of Operative Dentistry, 7th Edition.
Calcium hydroxide is considered the best choice for direct pulp capping in young permanent teeth because it has a high pH, which provides an antibacterial effect and promotes formation of a dentin bridge by stimulating odontoblast-like cell activity. Its ability to induce hard tissue barrier formation helps preserve pulp vitality and encourages healing. Although Mineral Trioxide Aggregate (MTA) is also effective, Calcium hydroxide remains the standard due to its long history of success and ease of use. Glass ionomer cement and zinc oxide eugenol lack the bioactive properties necessary for pulp healing.

Reference: Sturdevant's Art and Science of Operative Dentistry, 7th Edition.
The occlusal surface of a permanent molar involves pits and fissures primarily affecting the enamel and dentin within the occlusal grooves. According to Black's classification, lesions confined to these surfaces are categorized under Class I cavity preparations. This classification guides the removal of carious tissue and restoration without involving proximal surfaces. Therefore, a cavity on the occlusal surface does not extend into the interproximal areas, which are designated as Class II or other classes. Correctly classifying ensures precise removal and optimal restoration of functional anatomy.

Reference: Sturdevant's Art and Science of Operative Dentistry, 7th Edition.
The Submentovertex view primarily visualizes the base of the skull and the zygomatic arches, making it ineffective for evaluating maxillary fractures such as Le Fort I. In contrast, the Waters, Lateral cephalometric, and AP views provide clear visualization of the maxillary sinus walls and the horizontal fracture line characteristic of Le Fort I fractures. Accurate imaging of the lower maxilla and alveolar ridge is essential for diagnosis and surgical planning, which the submentovertex view fails to provide. Therefore, the Submentovertex view does not adequately demonstrate a Le Fort I fracture.

Reference: Peterson’s Principles of Oral and Maxillofacial Surgery, 3rd Edition.
The lateral oblique view provides a clear, detailed image of the mandibular body and angle region, allowing precise visualization of fracture lines. It is especially effective in demonstrating horizontally unfavorable fractures where muscle pull can cause displacement. This view reduces superimposition from overlapping bony structures, aiding in accurate assessment of fracture alignment and displacement. It is crucial for preoperative planning and fixation strategy in mandibular fractures.

Reference: Peterson’s Principles of Oral and Maxillofacial Surgery, 3rd Edition.
The PA Caldwell projection is specifically designed to visualize the frontal sinuses by angling the central ray 15 degrees caudad, which projects the frontal sinuses above the orbital shadows. This projection also provides clear visualization of the anterior ethmoid air cells, but its primary clinical use is for assessing frontal sinus pathology such as sinusitis or fractures. The clear delineation of the frontal sinus structure is essential for surgical planning or diagnosis. The other sinuses (sphenoid, maxillary) are better demonstrated by different views (e.g., Waters or lateral projections).

Reference: Merrill's Atlas of Radiographic Positioning and Procedures, 14th Edition.
The "hair on end" appearance on skull radiographs results from marrow hyperplasia due to increased erythropoiesis in response to chronic anemia. This feature is prominent in hemolytic anemias like beta-thalassemia major, sickle cell anemia, and congenital dyserythropoietic anemia, where the bone marrow expands significantly. In contrast, iron deficiency anemia does not cause marrow expansion or trabecular thickening, as it is a hypoproliferative anemia with reduced red cell production, thus lacking the "hair on end" radiographic changes.

Key surgical point: The presence of "hair on end" is indicative of marrow hyperactivity, not seen in iron deficiency anemia.

Reference: Harrison's Principles of Internal Medicine, 20th Edition.

ফ্রিতে ২ লাখ প্রশ্নের টপিক, সাব-টপিক ভিত্তিক ও ১০০০+ জব শুলুশন্স বিস্তারিতে ব্যাখ্যাসহ পড়তে ও আপনার পড়ার ট্র্যাকিং রাখতে সাইটে লগইন করুন।

লগইন করুন
The "floating teeth" radiographic appearance occurs when alveolar bone around the teeth is destroyed, making the teeth appear suspended. This feature is typical in conditions like Langerhans cell histiocytosis, osteomyelitis of the jaw, and central giant cell granuloma due to bone resorption. However, cherubism primarily involves bilateral multilocular radiolucencies in the jaw without actual tooth loosening or alveolar bone destruction that creates a floating teeth appearance. Instead, cherubism causes expansion of the jaw bones without the typical isolated alveolar bone loss seen in the other conditions.

Reference: Cawson's Essentials of Oral Pathology and Oral Medicine, 8th Edition.
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