Partial Denture ( Dr. Sokly) I

The classification of lever systems is based on the location of the resistance, the direction of effort, and the fulcrum line. This means that all of the options given in the question are correct. The location of the resistance refers to where the force is being applied, the direction of effort refers to the direction in which the force is being exerted, and the fulcrum line is the line around which the lever rotates. Therefore, all of these factors play a role in classifying a lever system.

The external finish line refers to the outer surface of the framework metal and the denture base plastic. This is the area where the metal and plastic materials meet and create the external boundary of the denture. It does not include the supporting tissues or the natural teeth.

In removable partial dentures, the health of gingival tissue is ensured by keeping a minimum distance of 6 mm for the major connector and a minimum distance of 4 mm for the major connector. These distances help to provide adequate space for the gingival tissue to maintain its health and prevent any irritation or damage caused by the denture. The major connector is an important component of the denture that connects the various parts together, and maintaining proper distances helps to ensure the overall comfort and health of the patient.

A linguo plate as a major connector for a mandibular RPD is indicated when the patient has a high floor of the mouth, a high lingual frenum, and lingual tori. These conditions can make it difficult to achieve proper retention and stability with other types of major connectors. The linguo plate can help distribute the forces evenly and provide better support for the removable partial denture.

The external finish line on a maxillary class 1 RPD originates from the lingual of the guide plane of the terminal abutment and ends at the hamular notch. The hamular notch is a bony prominence located at the posterior border of the hard palate. This is an important landmark for determining the position of the external finish line because it provides stability and retention for the removable partial denture. The other options, such as the glenoid fossa, buccal pouch, and Stenon's duct, are not relevant to the placement of the external finish line in a maxillary class 1 RPD.

The superior border of the mandibular lingual bar major connector should be positioned at least 3mm from the tooth/tissue junction. This is important to ensure adequate space for oral hygiene and to prevent irritation or damage to the gingival tissues. By keeping the connector at a distance from the tooth/tissue junction, it allows for proper cleaning and maintenance of the oral cavity.

The bulkiest position of a proximal minor connector is towards its lingual side. This means that the connector is thicker or larger on the lingual side compared to the other sides. This is important because the lingual side of the connector is in contact with the lingual gingiva or tongue, and it needs to provide adequate support and stability for the prosthesis. By making the lingual side bulkier, it ensures that the connector can withstand the forces and pressures exerted during normal oral function.

Guiding planes are typically multiple and parallel. This means that there are more than one guiding planes, and they are aligned in the same direction. This arrangement helps in providing stability and control to the object or system being guided. Multiple guiding planes distribute the load evenly and prevent any tilting or misalignment. Parallel guiding planes ensure that the object or system moves smoothly without any deviation from the desired path. Therefore, the correct answer is "usually multiple and usually parallel."

In this type of case, an indirect retainer is not needed. Indirect retainers are used in removable partial dentures (RPDs) to provide stability and prevent rotational movement of the denture. However, in certain cases where there is sufficient support and stability from other components such as major connectors, guide planes, and direct retainers, the use of an indirect retainer may not be necessary.

The horse-shoe major connector possesses the least strength and rigidity among the given options. This is because the horse-shoe design only covers the anterior teeth and does not extend to the posterior teeth or the palate. As a result, it lacks the additional support and stability that the other options provide. The palatal plate, anterior posterior palatal strap, and modified palatal strap all cover a larger area and offer more support, making them stronger and more rigid than the horse-shoe design.

Infrabulge clasps originate below the height of contour. This means that they are positioned below the highest point on the tooth's surface. Infrabulge clasps are used in removable partial dentures to provide stability and retention. By placing the clasps below the height of contour, they can engage undercuts on the tooth surface, which helps to secure the denture in place. This positioning also helps to distribute forces evenly across the tooth and minimize any potential damage or discomfort to the patient.

Indirect retainers are components of a removable partial denture (RPD) that help stabilize and prevent the denture from dislodging during function. They are typically located on the opposite side of the arch from the edentulous area and engage undercuts on the abutment teeth. In this case, the retentive tip is not a component of an RPD and therefore cannot act as an indirect retainer. Rests, proximal plates, and minor connector supporting rests are all components that can act as indirect retainers by engaging undercuts and providing stability to the denture.

A cingulum rest should be placed at the junction of the gingival and middle thirds of the incisor teeth. This is because the cingulum is the rounded area on the lingual surface of the incisor teeth, located at the junction of the gingival and middle thirds. Placing the rest at this location allows for proper support and stability of the denture or prosthesis. It also helps to distribute the occlusal forces evenly and prevent tipping or displacement of the prosthesis.

Denture bases of RPD offer secondary retention. Secondary retention refers to the stability and resistance to displacement of the denture base during function. It is achieved through the use of clasps, rests, and other components that provide support and stability to the denture. Primary retention, on the other hand, refers to the initial resistance to displacement of the denture base when it is first placed in the mouth, and mechanical retention refers to the use of mechanical devices such as clasps to retain the denture. Since the answer only mentions secondary retention, it implies that primary and mechanical retention are not provided by the denture bases of RPDs.

The correct answer is "All are correct". This means that if the RPD (Removable Partial Denture) was fabricated exactly as drawn on the design cast, all of the mentioned components - minor connectors, lingual bar, direct and indirect retainers - would be correct. This suggests that the design of the RPD includes all of these components in their appropriate positions and forms, ensuring proper function and support for the denture.

The I clasp is more aesthetically acceptable and causes less caries formation compared to other types of clasp designs. This is because the I clasp is designed to engage the undercut of the tooth in a more discreet manner, resulting in a more natural appearance. Additionally, the I clasp puts less pressure on the tooth, reducing the risk of caries formation.

When a minor connector contacts the tooth surface on either side of an embrasure, it should abruptly end at the tooth, be sharply angled, and not have space between it and the tooth. In other words, the minor connector should have a direct and tight fit against the tooth surface without any gaps or spaces. This ensures proper stability and support for the dental prosthesis.

The angle at the junction between the major connector and denture base minor connector should be less than or equal to 90 degrees. This is because a larger angle can create stress and strain on the denture base, leading to discomfort and potential damage. A smaller angle allows for better distribution of forces and reduces the risk of complications.

The minor connector that contacts the guiding plane has the same contour as the guiding plane, meaning it is shaped to fit the contours of the guiding plane. Additionally, it is thicker lingually than buccally, indicating that it is thicker on the side facing the tongue than on the side facing the cheek. This combination of characteristics allows the minor connector to effectively contact and engage with the guiding plane.

In a ring clasp, the retentive arm extends from the strut to the tip of the clasp. This means that the retentive arm starts from the part of the clasp that connects to the framework (the strut) and extends all the way to the tip of the clasp. This design allows the clasp to effectively retain the prosthesis in place by providing stability and preventing movement.

The sublingual bar is a component of a removable partial denture that rests on the lingual surface of the mandibular anterior teeth. It provides stability and support to the denture. Lingual tori, a high lingual frenum, and a high elevation of the floor of the mouth can all interfere with the placement and function of the sublingual bar. However, a large tongue does not directly contraindicate the use of a sublingual bar.

The correct answer is that the marginal ridge should be reduced by 1 mm. This means that when preparing the rest seat, the marginal ridge of the tooth should be reduced by a total of 1 mm. This reduction helps create a proper fit for the restorative material or prosthesis that will be placed on the tooth.

The minor connector for a mandibular distal extension will extend two-thirds the length of the edentulous ridge. This means that the connector will reach approximately two-thirds of the distance from the distal extension base to the most posterior edentulous area. This allows for proper support and stability of the removable partial denture in the mouth.

Removable partial denture movements away from tissue may occur due to various factors, including the pull of food, the movement of border tissues, and gravity. However, mastication, or the process of chewing, actually helps to stabilize the denture and prevent it from moving away from the tissue. Therefore, mastication is not a cause for removable partial denture movements away from tissue.

Denture bases of removable partial denture offer secondary retention. Secondary retention refers to the additional support provided by the surrounding oral structures, such as the remaining teeth and the soft tissues. This type of retention helps to stabilize the denture and prevent it from moving or dislodging during normal oral functions like eating and speaking. Primary retention, on the other hand, refers to the initial stability achieved by the intimate adaptation of the denture base to the underlying tissues. Mechanical retention refers to the use of clasps or other attachments to hold the denture in place.

The retentive tip is not a part of a removable partial denture that acts as an indirect retainer. Indirect retainers are designed to resist the rotational movement of the denture base around the fulcrum line. Rests, proximal plates, and minor connector supporting rests are all components that help stabilize the denture and prevent it from moving. However, the retentive tip is not involved in this function and therefore does not act as an indirect retainer.

Guiding planes are typically both single and multiple. This means that there can be instances where a guiding plane is singular, and other situations where there are multiple guiding planes. It is not limited to just one or the other. Additionally, there is no mention of the guiding planes being parallel, so it cannot be assumed based on the given information.

A minor connector located at the embrasure should be thickest toward the lingual surface. This is because the lingual surface of the teeth is generally stronger and can better withstand the forces of mastication. By making the minor connector thicker toward the lingual surface, it provides additional strength and support to the prosthesis, helping to prevent breakage or damage. Additionally, tapering away from the contact area would not provide the necessary support, and being thinnest toward the lingual surface may compromise the strength and stability of the prosthesis.

The Kennedy classification system is used to classify removable partial dentures (RPDs) based on the edentulous areas in the arch. Kennedy class I is defined as a situation where there are bilateral edentulous areas located posterior to the remaining natural teeth. In this case, the patient has lost all posterior teeth on both sides in the mandibular arch, which fits the criteria for Kennedy class I.

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The deepest part of a rest seat is towards the central fossa. The central fossa is the depression in the occlusal surface of a tooth that is located in the center of the tooth. This area tends to be deeper compared to other parts of the tooth, such as the disto-buccal line angle or the disto-lingual line angle. The marginal ridge is the elevated area on the occlusal surface that surrounds the central fossa. Therefore, the central fossa is the correct answer as it is the deepest part of a rest seat.

Protrusive or Retrusive movements refer to the forward or backward sliding of the mandible (lower jaw) in relation to the maxilla (upper jaw). These movements can also be called translatory or sliding movements.

The attachment between a porcelain tooth and denture base resin is classified as mechanical. This means that the bond between the two materials is primarily based on physical interlocking or mechanical retention, rather than chemical bonding or adhesion. Mechanical attachment is achieved through the use of retention grooves, undercuts, or other mechanical features on the tooth and denture base that create a secure fit and prevent dislodgement.

The correct answer is "One or two rests, a retentive arm, a bracing or reciprocating element, one minor connectors, one major connector". This answer is correct because it includes all the necessary components of a clasp assembly: one or two rests, a retentive arm, a bracing or reciprocating element, one minor connector, and one major connector.

When there is limited inter occlusal space (

The question asks for the clasps that are not infrabulge clasps. An infrabulge clasp is a type of clasp that is located below the height of contour of the tooth. Ibar, Modified T bar, and Roach clasp are all examples of infrabulge clasps. Therefore, the Akers clasp is the correct answer because it is not an infrabulge clasp.

The most apical portion of a cingulum rest is the floor of the preparation. This refers to the lowest part of the preparation where the rest seat is located. The rest seat is the area where the rest of the removable partial denture rests, providing stability and support. The floor of the preparation is crucial in ensuring proper function and fit of the denture.

Green casting wax is the best method to check occlusion intraorally to assess relining of RPD. Green casting wax is a type of wax that is specifically designed for dental use. It is easy to manipulate and shape, making it ideal for creating temporary restorations or assessing occlusion. It provides a good visual representation of the occlusal contacts and allows for adjustments to be made before finalizing the relining of the RPD. Articulating ribbon, mylar strips, and acrylic self-cure are not specifically designed for this purpose and may not provide accurate results.

The denture base acrylic resin minor connector on the patient's left side should be located 2/3 to 1/2 the length of the residual ridge. This positioning is important for stability and support of the denture. Placing the minor connector in this location helps distribute the forces evenly and prevents excessive stress on the remaining ridge. It also allows for proper function and comfort for the patient.

Multiple clasps are joined at the tip of reciprocal terminals. Reciprocal terminals are the components of a removable partial denture that provide stability and support by engaging undercuts on the abutment teeth. The tip of the reciprocal terminal is the point where the clasps are attached, allowing them to engage with the abutment teeth and provide retention for the denture. This positioning ensures that the clasps are properly aligned and can effectively distribute forces during mastication.

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Reciprocation between bracing and retentive components requires correct timing of contact during seating and removal of the removable partial denture (RPD). This means that the bracing components should make contact with the retentive components at the right time when the RPD is being inserted or removed from the mouth. This ensures proper stability and support of the RPD during function and prevents any unwanted movement or dislodgement.

Rest seats are usually located at the junction of enamel and dentin. This is because the enamel is the outermost layer of the tooth and provides a strong and stable surface for the rest seat. Additionally, the enamel is more resistant to wear and decay compared to dentin, making it a suitable location for the rest seat.

The hair pin clasp can approach an undercut at the point of origin of a clasp.

Direct retainers offer both primary retention and mechanical retention. Primary retention refers to the ability of the retainer to resist vertical dislodging forces, while mechanical retention refers to the physical engagement of the retainer with the abutment or tooth structure. In this case, the direct retainers provide both types of retention, making them effective in keeping the prosthesis securely in place. Secondary retention, on the other hand, refers to additional forms of retention, such as friction or adhesion, which are not mentioned in the given options.

The correct answer is "anterior posterior palatal strap." This type of major connector is commonly used in maxillary dentures to provide stability and support. It extends from the anterior region of the palate to the posterior region, connecting the anterior teeth and the posterior edentulous area. This design helps distribute the occlusal forces evenly and prevents the denture from rotating or dislodging during function.

Mastication is the process of chewing food, which involves the movement of the mandible. However, RPD (removable partial denture) movements away from tissues are not caused by mastication. The other options, such as the pull of food, moving border tissues, and gravity, can contribute to RPD movements away from tissues.

The effectiveness of an indirect retainer is influenced by various factors. Distance from the fulcrum line is important because the farther the retainer is from the fulcrum line, the more effective it is in preventing rotational movement of the denture. The supporting tooth surface is also crucial as it provides stability and resistance to movement. The quality of the direct retainer is important for secure attachment of the denture. However, increased flexibility of the minor connector used does not contribute to the effectiveness of the indirect retainer. In fact, a more rigid minor connector would provide better support and stability.

Posselt's envelope is a term used in dentistry to describe the path of movement of the mandible (lower jaw) in relation to the maxilla (upper jaw) during various functional movements such as chewing and speaking. It is a three-dimensional envelope that represents the maximum range of mandibular movement. Physiologic rest refers to the position of the mandible when it is at rest, which is within the limits of Posselt's envelope. Therefore, Posselt's envelope can be used to record the position of physiologic rest.

An undercut in relation to a tooth refers to an area of the tooth structure that extends below the survey line. The survey line is a reference line used in dentistry to determine the path of insertion and removal of a dental prosthesis. An undercut below the survey line allows for better retention and stability of the prosthesis. Undercuts above the survey line or on the occlusal surface are not considered ideal for proper functioning of the prosthesis.

The main aim of anterior-posterior tilt of the cast during surveying is to provide parallel proximal surfaces. This tilt helps in ensuring that the abutment teeth have parallel preparation surfaces, which is important for the proper fit and stability of the prosthesis. It allows for better distribution of forces and reduces the risk of interferences or unwanted contact between the prosthesis and adjacent teeth. Good esthetics and retention can also be achieved through this alignment, but the primary focus is on creating parallel proximal surfaces.

The vertical tissue ward movement of a denture is controlled by factors such as the total amount of occlusal load applied, the accurately fitting denture base, and the tissue of the residual ridge. The retentive tip of the clasp does not play a role in controlling this movement.

A mandibular movement that involves either opening or closing motions of the mandible around a horizontal axis that is common to both condyles is best classified as a hinge movement. In a hinge movement, the mandible acts like a hinge, allowing the jaw to open and close in a swinging motion around a fixed axis. This type of movement is different from translatory excursion, which involves a sliding motion of the mandible, and centric relation, which refers to the position of the mandible when the teeth are in maximum intercuspation.

The correct answer is "To prevent vertical dislodgement of the distal extension base of a RPD." An indirect retainer is a component of a removable partial denture (RPD) that helps to stabilize and prevent movement of the denture base. It is specifically designed to resist vertical forces that could dislodge the distal extension base of the RPD. The other options listed are not the primary functions of an indirect retainer.

Lingual plating should be supported with rests because rests help in preventing the movement of the denture and provide stability. They also distribute the occlusal forces evenly and reduce the load on the abutment teeth. Rests are essential for proper support and retention of the lingual plate, ensuring the success and longevity of the denture.

The correct answer is "does not cover the tuberosity." The gridwork of the minor connector on a maxillary class 1 removable partial denture does not cover the tuberosity. The purpose of the minor connector is to connect the major connector to the rest of the framework and provide stability and support to the partial denture. The minor connector should be designed in a way that it does not impinge on the soft tissues or cover any anatomical structures such as the tuberosity.

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The function of an indirect retainer is to prevent vertical dislodgement of the distal extension base of a removable partial denture. It helps to stabilize the prosthesis by resisting forces that may cause the denture to lift or dislodge in a vertical direction. This is important for maintaining the stability and function of the partial denture during mastication and other oral activities.

Class III of Kennedy is the correct answer because it is the only class that never has an axis of rotation. In class I, there is an axis of rotation around a single tooth or edentulous area. In class II, there is an axis of rotation around a single tooth or edentulous area and a second axis of rotation around a second tooth or edentulous area. In class IV, there is an axis of rotation around two teeth or edentulous areas. However, in class III, there is no axis of rotation, as there are no teeth or edentulous areas to serve as a pivot point.

Bar type configuration of clasps can also be used for retention. This means that the clasps are designed to keep the denture securely in place and prevent it from moving or dislodging during normal oral functions such as eating and speaking. The bar configuration provides a stable and secure grip on the abutment teeth, ensuring that the denture remains in position and does not easily come loose.

Clasps in a removable partial denture (RPD) help stabilize the RPD by controlling occlusal movement. They provide support and stability to the RPD by engaging undercuts on the abutment teeth, preventing the prosthesis from dislodging during functional movements such as biting and chewing. Clasps do not control gingival movement or prevent excessive biting forces on the abutment. They may also function as indirect retainers, providing additional stability to the RPD by resisting rotational forces.

The supporting strut for a ring clasp should be placed on the non-retentive side of the abutment. This is because the non-retentive side is the side opposite to the direction of displacement of the prosthesis during function. Placing the strut on this side helps to stabilize the clasp and prevent it from rotating or dislodging during mastication or other functional movements. By placing the strut on the non-retentive side, it provides support and stability to the clasp without interfering with its retentive function.

A combination clasp assembly generally consists of a bracing arm, a retentive arm, and rests. The bracing arm provides stability and support to the clasp assembly, while the retentive arm helps in retaining the clasp on the abutment tooth. Rests are used to provide additional support and stability to the clasp assembly by resting on the adjacent teeth.

The superior border of the major connector is not acceptably adapted to the teeth. This means that the upper edge of the major connector, which is a component of a dental prosthesis, is not properly adjusted or fitted to the teeth. This lack of proper adaptation can lead to discomfort or instability of the prosthesis.

The lattice pattern is preferable for the mesh pattern of a minor connector because it provides excellent attachment while minimizing warping in resin bases. This means that the lattice pattern allows for a strong and secure connection between the denture base and major connector, while also reducing the risk of distortion or damage to the resin material. This ensures a more stable and durable denture construction.

Dual path of insertion should be considered when designing an RPD for the mandibular arch because it allows for easier insertion and removal of the prosthesis. This is especially important in cases where there are limited interocclusal space or undercuts in the abutment teeth. By incorporating a dual path of insertion, the RPD can be inserted and removed in a more comfortable and efficient manner for the patient.

The distance of the indirect retainer from the fulcrum line is affected by the location of the principal abutment, the length of the distal extension base, and the location of the fulcrum line. However, the rigidity of the indirect retainer does not affect this distance.

A class I modification 0 of RPD typically has two clasps.

The tripod of dental surveyor is used for recording the relation of the cast to the surveyor. This means that the surveyor is used to measure and record the position of the cast in relation to the surveyor. This is important for ensuring accurate and reproducible measurements and for determining the proper positioning of clasp assemblies and identifying undercut areas on the tooth. The tripod method provides stability and consistency in recording these measurements.

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The occlusal rest preparation should be spoon-shaped, meaning it should have a concave shape resembling a spoon. This shape allows for better distribution of forces and reduces the risk of fracture. Additionally, the preparation should be at least 1/3 the bucco-lingual width of the occlusal surface to provide adequate support for the prosthesis. It should also be at least one millimeter deep to ensure stability and prevent displacement of the prosthesis. Therefore, all of the given options are correct explanations for the occlusal rest preparation.

The correct answer is Half and half clasp, Ring clasp. These clasps commonly utilize lingual undercut, which is a groove or depression on the inner surface of the tooth that allows the clasp to engage and hold the denture in place. The Half and half clasp and Ring clasp are designed to engage the lingual undercut for stability and retention.

The non-retentive clasp arm is best placed between the middle and gingival third of the tooth. This placement allows for optimal retention and stability of the clasp arm. Placing the clasp arm in this location ensures that it engages the tooth structure effectively, providing support and preventing displacement of the prosthesis. Additionally, this placement minimizes the risk of damaging the gingival tissues and promotes proper oral hygiene maintenance.

The height of the floor of the mouth can be determined by using a periodontal probe and an individualized impression tray. The periodontal probe is a dental instrument used to measure the depth of the gingival sulcus, which is the space between the tooth and the gum tissue. By measuring the depth of the gingival sulcus in different areas of the mouth, the height of the floor of the mouth can be determined. Additionally, an individualized impression tray can be used to take an impression of the mouth, which can provide further information about the height and contours of the oral structures.

A jaw which is moving in a "left or right" motion would be called lateral movement.

The correct answer for this question is Kennedy class I. The Kennedy classification system is used to categorize removable partial dentures (RPDs) based on the edentulous areas and the remaining teeth. Kennedy class I refers to a situation where there are bilateral edentulous areas located posterior to the remaining natural teeth. In this case, the answer is Kennedy class I because there is only one edentulous area located posterior to the remaining teeth, indicating a unilateral situation.

The limitations to the use of internal attachment include the size of the pulp, clinical crown shortness, and the cost of the prosthesis. However, availability is not a limitation to the use of internal attachment. This means that the availability of internal attachment is not a factor that restricts or hinders its use.

The gingivally approaching clasps have several advantages over occlusally approaching clasps, including less tooth contact, less distortion of coronal contours, and being esthetically superior in most cases. However, the one advantage they do not have is being less bothersome to vestibular tissues.

All of the given options are correct because in Centric Relation and Centric Occlusion, the teeth are in contact and properly aligned. In Edge to Edge Incisor Contact, the incisors make direct contact with each other. In Maximum Mandibular Protrusion, the lower jaw is extended forward, causing the teeth to come into contact. In Negative, Horizontal, and Vertical Overlaps at incisors, the upper and lower teeth overlap in various ways, indicating contact between them.

A ring clasp commonly utilizes lingual undercut because it is designed to encircle the tooth and engage the undercut on the lingual surface. This allows for better retention and stability of the clasp on the tooth. Extended arm clasp, back action clasp, and embrasure clasp do not typically utilize lingual undercut in the same way as a ring clasp.

A continuous bar is known as both a Kennedy bar and a cingulum bar.

The correct answer is "Potentially more rigid." This means that lattice type of grid work minor connectors have the potential to be more rigid compared to other options. This suggests that these connectors may provide better stability and support for the dental prosthesis.

The marginal ridge for a rest seat should be reduced by at least 1.5mm. Rest seats are prepared on abutment teeth to provide support and stability for a removable partial denture. The marginal ridge reduction helps to create adequate space for the rest seat and ensure proper fit and function of the denture. A reduction of 1.5mm is considered sufficient to accommodate the rest seat without compromising the structural integrity of the abutment tooth.

In maximum protrusion, the mandible is positioned in its most forward position. This position is achieved when the condyles are in their most anterior position within the glenoid fossa. When the mandible is in maximum protrusion, there is a significant increase in vertical dimension of occlusion (VDO) compared to centric occlusion. This is because the condyles are more anteriorly positioned, allowing for greater separation between the upper and lower teeth. Therefore, maximum protrusion would result in the greatest increase in VDO compared to the other mandibular positions mentioned.

Keeping a light occlusion on the distal extensions is the best way to prevent the negative effects of additional load on class I Kennedy abutments. This means that the contact between the upper and lower teeth in the distal extension area should be minimal or light. This helps to distribute the load evenly and reduce the stress on the abutments. Splinting the abutment with adjacent teeth, placing distal rests on the distal abutment, and regular relining of distal extensions may not provide the same level of protection against the negative effects of additional load.

The labial bar is indicated when there is a lingual inclination of teeth. This means that the teeth are tilted towards the tongue rather than being in their proper alignment. The labial bar is a type of orthodontic appliance that is used to correct this issue by applying pressure on the lingual side of the teeth, pushing them back into their correct position. This appliance is commonly used when there is a need to correct malocclusion or improve the alignment of teeth.

Impression materials are used to record the supporting form of an edentulous area in a distal extension denture base. Waxes, silicone impression materials, and impression paste are all commonly used for this purpose. However, hydrocolloids are not typically used as impression materials in dentistry. Hydrocolloids are more commonly used in wound care and dressings, not for dental impressions. Therefore, hydrocolloids are the exception in this list of impression materials.

The first statement is false because an anterior posterior palatal strap major connector is actually more rigid than a horseshoe major connector. However, the reason is true because the AP strap major connector has less width, which contributes to its reduced rigidity compared to the horseshoe major connector.

The Kennedy classification system is used to classify removable partial dentures (RPDs) based on the edentulous areas in the arch. Kennedy class III mod. I is the correct answer because it describes a situation in the mandibular arch where there are missing teeth #35, 36, and 46. This classification indicates that there are bilateral edentulous areas posterior to the remaining natural teeth, with the most posterior edentulous area being on one side only.

The last step in the given list is "Centric relation records." This step is typically performed after the other steps mentioned. Rest preparation, framework try-in, and altered cast impression are all steps that are typically done before taking centric relation records. Therefore, centric relation records are the final step in this sequence of procedures.

The correct answer is "By scoring as well as tripoding with pits." This means that the relation of the cast to the surveyor can be recorded by both scoring the base of the cast and tripoding with pits. Scoring refers to marking or engraving the base of the cast, while tripoding with pits means using small pits or holes to secure the cast in place. Both methods are used together to accurately record the relation between the cast and the surveyor.

A dual path of insertion should be considered when designing an RPD for the mandibular arch. This means that the RPD should be designed in a way that allows for insertion and removal of the prosthesis along two different paths. This is important because it helps to minimize trauma to the remaining teeth and tissues, as well as improve the stability and retention of the RPD. By considering a dual path of insertion, the RPD can be more comfortable and functional for the patient.

Guiding planes are surfaces on abutment teeth that are prepared to guide the movement of a partial denture during insertion and removal. They are typically contacted by various parts of the partial denture, such as the body of the extracoronal direct retainer and stabilizing arm direct retainer. The minor connector of the indirect retainer also contacts the guiding planes. However, the minor connector of the denture base does not come into contact with the guiding planes.

The I bar clasp is a type of clasp used in removable partial dentures. It is designed to provide retention and stability to the denture. The statement "Whole arm of the clasp contacts abutment" is incorrect because in an I bar clasp, only the tip of the clasp arm should contact the abutment tooth. The rest of the arm should be away from the tooth to allow for flexibility and movement. This helps to distribute forces evenly and prevent damage to the abutment tooth.