dump mixed topic questions (138 টি প্রশ্ন )
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A major issue with a complete denture opposing natural teeth is abrasion of the artificial teeth. Natural teeth are composed of enamel, which is significantly harder than the acrylic or resin materials used in denture teeth. This hardness difference leads to accelerated wear and surface loss of the denture teeth when in occlusion with natural dentition. This wear compromises the occlusal vertical dimension, aesthetics, and function of the denture, necessitating frequent adjustments or replacements. Therefore, selecting wear-resistant materials or protecting the denture teeth is critical in such cases.

Reference: Textbook of Prosthodontics, Dr. A. R. Pradeep, 2nd Edition.
Tripoding is a technique used in prosthodontics to ensure a reproducible and stable positioning of a dental cast on a surveyor. By marking three points on the cast, it allows the clinician to reposition the cast in the exact same orientation every time it is placed on the surveyor. This is crucial for designing and fabricating removable partial dentures, as it maintains consistent analysis of undercuts, guide planes, and path of insertion. Without tripoding, variations in cast orientation could lead to inaccuracies in prosthesis design.

Reference: Contemporary Fixed Prosthodontics, Stephen F. Rosenstiel, Edition 5.
An effective clasp assembly must engage more than 180° of the greatest circumference of the crown to ensure optimal retention and stability. Covering over half the circumference allows the clasp to resist dislodging forces better, providing a firm mechanical grip on the tooth. This design maximizes retentive arm flexibility while maintaining adequate tooth protection, preventing unwanted movement of the prosthesis during function. Less coverage would reduce retention and increase the risk of clasp deformation or tooth damage. Therefore, more than 180° coverage is essential for durable and functional clasp performance.

Reference: Prosthodontics, Anil Chandra, 1st Edition.
An obturator designed to restore defects specifically in the nasal meatus area is termed a Meatal obturator. This type of obturator effectively closes openings in the nasal passage, aiding in the separation of oral and nasal cavities and improving functions like speech and swallowing. It is distinct from palatal, pharyngeal, or alveolar obturators, which address defects in the palate, pharynx, or alveolar ridge respectively. The naming is based on the precise anatomical site being restored, ensuring targeted rehabilitation tailored to the defect's location.

Reference: Prosthodontic Treatment for Edentulous Patients, George A. Zarb, Edition 13.
The point contact pontic design is preferred in the maxillary posterior region because it provides adequate cleansability and functional efficiency. Unlike the ridge lap or saddle pontic, it minimizes tissue contact, reducing plaque accumulation and irritation. It allows food to pass freely beneath the pontic, promoting better oral hygiene and preventing soft tissue inflammation. The hygienic pontic, while also cleanable, is less esthetic and less suitable for maxillary posterior areas where appearance is important. Therefore, point contact balances esthetics, hygiene, and tissue health in this region.

Reference: Contemporary Fixed Prosthodontics, Rosenstiel, Edition 5.
One-piece post crowns are not recommended because they combine the post and crown into a single unit, making them difficult to adapt and adjust within the root canal and the coronal portion. This can lead to poor fit, higher stress concentration, and increased risk of root fracture. Additionally, they do not allow for intra-radicular retreatment or post modification once cemented. Contemporary restorative principles favor separating the post and core to enhance customization, reinforcement, and long-term prognosis. Hence, one-piece post crowns should not be attempted in clinical practice.

Reference: Principles and Practice of Operative Dentistry, Sturdevant, 5th Edition.
The iliac crest graft is considered the best option for reconstruction of large mandibular defects due to its abundant corticocancellous bone, large volume, and excellent osteogenic potential. This graft provides structural support and allows for easy shaping to match the mandibular contour. Additionally, it offers a high success rate in vascularization and integration with the mandibular site. Unlike other grafts, the iliac crest provides a thinner cortex and more cancellous bone, promoting faster revascularization and better incorporation, essential for large defects. Its donor site morbidity is acceptable compared to other options providing similar bone volume.

Reference: Contemporary Oral and Maxillofacial Surgery, James R. Hupp, 7th Edition.
The reciprocal arm of a removable partial denture is designed to provide lateral stability by applying a counteractive force to the tooth when the retentive arm engages undercuts during insertion or removal. This prevents unwanted tooth movement or tipping caused by the retentive arm. Contacting the tooth only when the retentive arm is activated ensures minimal stress on the abutment tooth during function and avoids continuous pressure that could cause trauma or discomfort. Hence, the reciprocal arm should engage only during removal or insertion, not at all times or never.

Reference: Removable Partial Dentures, Carr and Brown, 13th Edition.
The reciprocal arm of a clasp assembly in removable partial dentures must be always passive to provide a stable counterforce against the retentive clasp arm during insertion and removal. This prevents tooth movement or trauma by stabilizing the abutment tooth without engaging undercuts or causing excessive pressure. Active force from the reciprocal arm could lead to tooth mobility or periodontal damage. Therefore, ensuring passive contact is critical for maintaining both tooth integrity and prosthesis function.

Reference: Contemporary Fixed Prosthodontics, Rosenstiel, Edition 5.

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
Insertion of immediate dentures is usually associated with less pain as the denture acts as a splint. This is because the denture provides support and protection to the freshly operated alveolar ridge, minimizing movement and trauma to the surgical site. It also helps in controlling postoperative bleeding and swelling. By stabilizing soft tissues, immediate dentures reduce the risk of irritation and discomfort, promoting more comfortable healing compared to leaving the site exposed. This splinting effect is crucial for patient comfort during the critical initial healing phase.

Reference: Oral & Maxillofacial Surgery, Raymond J. Fonseca, 4th Edition.
Intracanal medication in endodontics is necessary for complete canal cleaning because it helps eliminate bacteria that mechanical instrumentation and irrigation alone cannot remove. These medications, such as calcium hydroxide, provide sustained antimicrobial action within the complex root canal system, reducing bacterial load and preventing reinfection. Additionally, intracanal medicaments aid in dissolving necrotic tissue remnants and controlling inflammation, which are crucial for successful healing of periapical tissues. Without intracanal medication, complete microbial eradication is often unachievable, compromising treatment outcomes.

Reference: Pathways of the Pulp, Cohen & Hargreaves, 12th Edition.
The 'cotton wool' appearance on radiographs is a classic feature of Paget's disease of bone. It results from the combination of excessive bone resorption and abnormal bone formation, leading to a patchy, sclerotic pattern that resembles cotton wool. This pattern reflects the disorganized and thickened trabecular bone characteristic of this condition. Recognizing this radiological sign is crucial for diagnosis and surgical planning to avoid complications during orthopedic interventions.

Reference: Gray's Anatomy, Susan Standring, 42nd Edition.
The principal advantage of using direct digital image receptors over traditional radiographic film is the significant reduction in patient radiation exposure. Digital receptors are more sensitive to X-rays, requiring less radiation to produce high-quality images. This not only improves patient safety by minimizing dose but also enhances workflow efficiency due to immediate image availability. Unlike film, which demands higher exposures and chemical processing, digital systems optimize dose without compromising diagnostic accuracy. Therefore, maximizing patient protection while maintaining image quality is the key clinical benefit of direct digital receptors.

Reference: Radiologic Science for Technologists, Stewart C. Bushong, 11th Edition.
Feather edge or shoulder bevel crown preparations are contraindicated because they provide insufficient tooth structure reduction, leading to inadequate crown thickness and compromised strength. This margin design also results in poor marginal seal and increased microleakage. Furthermore, feather edge margins are difficult to capture accurately in impressions, which affects crown fit. For long-term success, a well-defined margin, such as a shoulder or chamfer, is essential to ensure optimal crown retention, resistance, and esthetics. Therefore, feather edge preparations are not suitable for any crown type.

Reference: Principles and Practice of Operative Dentistry, Joseph Massler, 5th Edition.
Pulpal inflammation commonly extends to the periodontal area through the furcation area because it contains multiple lateral and accessory canals that connect the pulp chamber with the periodontal ligament. These anatomical communications act as pathways for inflammatory cells and bacterial products, especially in multi-rooted teeth where the furcation is a convergence zone. This connection facilitates the spread of infection from the pulp to the surrounding periodontal structures, leading to combined endodontic-periodontal lesions. Recognizing the furcation area's role is crucial during surgical intervention to prevent persistent infection.

Reference: Pathways of the Pulp, Cohen & Hargreaves, 12th Edition.
The main component of most root canal sealers is zinc oxide eugenol because it provides excellent sealing ability, antimicrobial properties, and biocompatibility. Its setting reaction creates a tight seal between the gutta-percha and the canal walls, preventing microleakage and reinfection. Additionally, its antibacterial effect helps reduce residual bacterial load within the canal system, promoting healing. Zinc oxide eugenol-based sealers also exhibit good manipulation and radiopacity, essential for clinical use. This makes it the preferred and widely used material for root canal obturation.

Reference: Grossman’s Endodontic Practice, James L. Gutmann, 13th Edition.
The "hanging drop" sign on radiographs is indicative of an orbital floor fracture, where the inferior rectus muscle and orbital contents herniate into the maxillary sinus. This results in a characteristic drooping or "hanging" appearance of soft tissue within the sinus on imaging. Recognition of this sign is critical as it guides the surgeon to evaluate for muscle entrapment and orbital volume changes, which can lead to diplopia and enophthalmos. Prompt surgical repair is essential to restore orbital anatomy and prevent long-term functional and cosmetic deficits.

Reference: Oral and Maxillofacial Trauma, James R. Hupp, 5th Edition.
Scintigraphy uses radioactive compounds (radiotracers) that selectively accumulate in specific tissues, allowing visualization of their function and structure. These compounds emit gamma rays detected by a gamma camera, producing images that highlight tissue activity and pathology. This technique is essential for diagnosing metabolic and functional abnormalities in organs like the thyroid, bone, and heart. Unlike ultrasound, MRI, or CT, which rely on physical or magnetic properties, scintigraphy depends on radioactive tracers with tissue affinity to provide targeted, functional imaging.

Reference: Robbins Basic Pathology, Kumar, Abbas, Aster, 10th Edition.
The most common route for microorganisms to reach the dental pulp is through carious lesions and cavity preparations. This is because dental caries cause enamel and dentin breakdown, allowing bacteria to directly invade the pulp chamber. Cavity preparations also create a direct communication between the oral environment and the pulp. Other routes, like periodontal ligament or blood supply, are less direct and less frequent pathways for microbial invasion. Therefore, maintaining proper caries control and aseptic techniques during cavity preparation is critical to prevent pulpal infections.

Reference: Pathways of the Pulp, Cohen & Hargreaves, 12th 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 primary gutta-percha cone must fit tightly in the apical third because this area is critical for achieving a proper seal and preventing microleakage. A snug fit in the apical third ensures the elimination of voids and reduces the risk of bacterial penetration, which is essential for successful root canal therapy. Additionally, the apical constriction acts as a natural barrier, making it the ideal target for the primary cone to achieve an effective apical seal. Improper fit in this region can compromise the treatment outcome and cause persistent infection.

Reference: Endodontics: Principles and Practice, Mahmoud Torabinejad, 6th Edition.
Dry heat sterilization requires higher temperatures and longer exposure times compared to autoclaving, which uses moist heat and steam under pressure. This makes dry heat sterilization significantly more time consuming. While autoclaving typically sterilizes instruments in 15-30 minutes, dry heat methods may take 1-2 hours or longer to achieve equivalent microbial kill. The prolonged duration is due to the need for dry heat to penetrate and oxidize cellular components effectively without the aid of steam. Therefore, its main disadvantage compared to autoclaving is being time intensive, limiting its practical use in busy surgical settings.

Reference: Principles and Practice of Infectious Diseases, Mandell, Douglas, and Bennett, 9th Edition.
The isthmus width for an inlay preparation is generally 1/3 of the intercuspal distance to ensure adequate strength and resistance form without excessive removal of tooth structure. This dimension maintains the structural integrity of the tooth while allowing proper clearance for restorative material. A width less than 1/3 may compromise durability, while wider preparations (>1/3) increase the risk of weakening the cusps. Thus, 1/3 intercuspal distance balances conservation and mechanical stability of the inlay restoration.

Reference: Sturdevant's Art and Science of Operative Dentistry, Roberson, 7th Edition.
The main function of pins in an amalgam restoration is to increase the resistance and retention of the restorative material. Pins provide additional mechanical retention by anchoring the amalgam into the dentin, especially in cases with insufficient tooth structure to support the restoration. This helps to prevent dislodgement and improves the longevity of the restoration under occlusal forces. Pins do not affect esthetics, microleakage, or finishing but are primarily used to enhance the stability of the amalgam filling.

Reference: Sturdevant's Art and Science of Operative Dentistry, Roberson, 7th Edition.
The intercuspal width of an occlusal amalgam cavity preparation should be approximately 1/3 of the buccolingual width of the tooth. This ensures enough bulk of amalgam to withstand occlusal forces while preserving sound tooth structure. A preparation wider than 1/3 risks weakening the tooth and compromising resistance form, whereas a narrower width might not provide adequate access for complete caries removal and amalgam placement. Maintaining this dimension optimizes structural integrity and longevity of the restoration.

Reference: Sturdevant's Art and Science of Operative Dentistry, Roberson, 7th Edition.
Glucose is considered the least cariogenic sugar because it is less readily fermented by oral bacteria compared to sucrose, fructose, and lactose. Sucrose is the most cariogenic sugar as it is metabolized by bacteria to produce sticky extracellular polysaccharides that enhance biofilm formation and acid production, leading to enamel demineralization. Glucose does not promote this sticky matrix formation, resulting in less plaque adherence and acid damage. Therefore, glucose poses a lower risk for dental caries development relative to the others listed.

Reference: Oral Pathology, Neville et al., 4th Edition.
The preferred treatment for an odontogenic keratocyst is excision because it allows for complete removal of the cyst lining, which is critical to reduce the high recurrence rate associated with residual cystic epithelium. Enucleation with peripheral ostectomy is often performed to ensure complete removal of potentially infiltrative epithelial remnants. Simply observing the lesion risks progression and complications such as infection or bone destruction. Marsupialization may be used as an initial step to reduce cyst size, but definitive surgical excision provides the best long-term control. Radiation therapy is not indicated due to the benign nature of the lesion.

Reference: Oral and Maxillofacial Pathology, Neville et al, 4th Edition.
The recommended extraction sequence in the maxillary segment begins with the 3rd molars and progresses anteriorly to the canines to facilitate surgical access and minimize trauma. Removing posterior teeth first (3rd molars, 2nd molars, then premolars) creates the necessary space and visibility for subsequent extractions of more anterior teeth. Extracting anterior teeth prematurely can complicate flap design and healing. Additionally, this order helps preserve alveolar bone and soft tissue contours for potential prosthetic or orthodontic procedures. Overall, the sequence optimizes surgical efficiency and patient outcomes.

Reference: Oral and Maxillofacial Surgery, Raymond J. Fonseca, 3rd Edition.
During a posterior superior alveolar nerve block, the needle is inserted near the posterior aspect of the maxilla to reach the nerve branches. The injection site lies close to the infratemporal fossa, a deep space located posterior to the maxilla. If aseptic technique is compromised, infection can be introduced directly into this anatomical space. The infratemporal fossa communicates with several vital spaces, increasing the risk of spread of infection. Thus, the location of the needle tip during this block predisposes the patient to infection in the infratemporal fossa rather than other adjacent areas such as the maxillary sinus or pterygopalatine fossa.

Reference: Oral and Maxillofacial Pathology, Neville et al., 4th Edition.
Infections originating in the submandibular and submental spaces commonly spread downward into the anterior mediastinum via the fascial planes of the neck. This occurs because the deep cervical fascia and investing layers create a continuous pathway from these spaces to the anterior mediastinum. Such spread can rapidly lead to mediastinitis, a life-threatening condition requiring prompt surgical drainage and broad-spectrum antibiotics. Understanding this anatomical relationship is vital in managing deep neck infections and preventing fatal complications.

Reference: Gray's Anatomy, Standring S., 42nd 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 lingual split technique involves creating a surgical access on the lingual side of the mandible. This approach can unintentionally lead to the disruption of the thin lingual cortical plate and the underlying soft tissues, which may cause opening up of the facial spaces on the lingual side and the floor of the mouth. This can result in potential complications such as spread of infection and difficulty in wound closure. Therefore, the main disadvantage is the increased risk of exposing and opening these anatomical spaces, which must be carefully managed during surgery to prevent postoperative morbidity.

Reference: Oral and Maxillofacial Surgery, Raymond J. Fonseca, 3rd Edition.
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