What terms are explained and answered in the prosthodontics exam?
Prosthodontics: the clinical medical science that uses artificial devices to repair various missing teeth and their auxiliary tissues and various defects in maxillofacial region and maintain their corresponding physiological functions.
2. Tooth defect: the hard tissue of teeth is damaged, defective or deformed to varying degrees, resulting in abnormal tooth shape, occlusion and abutment.
3. Retention form: the geometric shape that enables the prosthesis to resist external forces without knowing the shedding and displacement. 4. Resistance shape: Geometric shape that enables restorations and tooth replacements to resist jaw force without damage and fracture.
5. Dental preparation: generally refers to the technical operation of restoring, reconstructing and reconstructing the anatomical shape and physiological function of human teeth, and trimming the shape of the affected teeth or adjacent teeth through dental instruments to meet the needs of retention, support, appearance, beauty and function of restorations.
6. Temporary crown: it is a temporary fixed prosthesis that patients can't take off freely after the fixed teeth are prepared and before the final prosthesis is cemented.
7. Transitional prosthesis: It is a temporary prosthesis made to treat some diseases of jaw system or to make a definite diagnosis, beautify and improve masticatory function, and also to provide more treatment schemes for the design and manufacture of the final prosthesis.
8. Jaw frame: also known as occlusal device, it is an instrument that imitates the human upper and lower jaw joints, fixes the upper and lower jaw models and jaw brackets, and simulates the mandibular movement to a certain extent.
9. Inlay: It is a kind of restoration embedded in teeth, which is used to restore the shape and function of tooth defects. 10, post crown: it is a kind of full crown restoration which uses retention post to insert into root canal to obtain retention. 1 1, dentin collar: a circle of dentin above the crown edge and below the nuclear root surface ≥1.5 mm. 12, full crown: it is a restoration made of dental restoration materials covering the full crown. It is the main restoration form of tooth defect.
13. cast metal crown: a metal restoration covering the surface of the crown completed by casting process. 14. Porcelain fused to metal crown (PFM): It is a kind of restoration that the composite structure of gold and porcelain is fused to the cast metal base crown with low melting point porcelain under vacuum. 15. All-ceramic crown: a restoration made of ceramic materials covering the surface of the full crown.
16, dentition defect: refers to the loss of some natural teeth in single jaw or upper and lower dentition, which destroys the integrity of dentition. 17, Fixed Denture (FPD): It uses natural teeth or roots with gaps at both ends or one end as the restoration of abutment, so it is often called fixed bridge 18. Retainer: refers to the full crown, post crown, partial crown or inlay made and bonded on abutment, which is connected with the bridge through connectors to fix the fixed bridge and abutment. And keep the fixed bridge19; The bridge body is the part where the fixed bridge restores the shape and function of the fixed teeth; The connector is the part between the fixed bridge and the fixer.
2 1. Double-ended fixed bridge: there are retainers at both ends, and the connection form between retainer and bridge is fixed connection.
22. Semi-fixed bridge: there are different connectors at both ends, which are fixedly connected with the retainer; The other end is a movable connector, which is mostly a bolt structure, and the bolt is located near the clearance side of the cage.
23. Single-ended fixed bridge: only one end has a retainer, and the bridge and the retainer are connected by a fixed connector, and the other end is a completely free cantilever without abutment support.
23. Periodontal potential: the average jaw force is 22.4~68.3kg, but in daily life, the jaw force required for chewing food is generally 65,438+00 ~ 23 kg, which is only half of the jaw force used by teeth. Periodontal tissue also stores a considerable reserve force, called ~ 24. Removable partial denture (RPD) refers to the use of natural teeth left in the mouth.
25. Anatomical teeth (with fangs): The cusp inclination is 30-33 degrees, which is similar to the natural occlusal surface that just erupted.
26. Non-anatomical teeth (no fangs or flat fangs): the articular surface has no sharp corners and inclined planes, the shape of the buccal-lingual axial surface is similar to that of anatomical teeth, and the articular surface has overflow grooves.
Semi-anatomical teeth: the occlusal surface has cusp inclination, but the cusp inclination is small, about 20 degrees. There is a certain locking relationship between the upper and lower cusps, and the chewing efficiency is good, which is less than the lateral resultant force of anatomical teeth. It is widely used in clinic. The bracket of removable partial denture refers to a rigid (metal) device placed on natural teeth to prevent the gingival displacement of the restoration and transmit the resultant force to the teeth.
Observation line: also known as lateral movement, it refers to the dividing line drawn by the same method, which is used to distinguish the concave area and non-concave area of soft and hard tissues. 29. Class I traverse: the observation line drawn when the abutment inclines in the opposite direction to the notch and the main inverted concave area of the abutment is far away from the notch side. Type ⅱ traverse: the observation line drawn when the abutment inclines to the notch direction, and the main inverted concave area of the abutment is near the notch side.
3 1 type, ⅲ transverse: the observation line drawn when the abutment is inclined to the buccal side or lingual side, or when the tooth itself is inclined, the undercut is common and remarkable. 32. Locked state: refers to the state that the denture is constrained because the designed seating path is inconsistent with the actual dislocation direction of the denture in the functional state.
33. Indirect retainer: Definition: The device that assists the retention of direct retainer is a retention device designed to prevent the denture from tilting, swinging, rotating and sinking. Mainly to strengthen the stability of denture.
34. Maxillary support: refers to the part of the clasp body extending to the occlusal surface of abutment, which is a rigid (metal) device to prevent the gingival of the prosthesis from shifting in the direction and transmit the occlusal force to the teeth.
35. Complete dentures: Dentures made for patients with missing dentition are called complete dentures.
36. dentition loss: refers to the absence of any natural teeth or roots on the entire dental arch, also known as edentulous jaw.
37. Main bearing area: refers to the area perpendicular to the direction of jaw force. Including the crest of alveolar ridge, palatal vault, buccal exfoliation area and other areas where bone resorption usually occurs.
38. Denture gap: The potential gap in the mouth to accommodate dentures is the space occupied by natural dentition.
39. Recording of jaw position: It refers to determining and recording the appropriate height of the patient's sub-surface13 and the jaw position relationship of the two condyles in the physiological posterior position of mandibular joint depression, and reconstructing the median relationship of the complete denture of edentulous patients based on this jaw position relationship.
40. Median mandibular position: When the upper and lower dentition contact, the front teeth cover the normal jaw, and the rear teeth and maxillofacial regions contact each other. At this time, the relationship between the upper and lower jaws is the most extensive.
4 1, oral vestibule: located between alveolar ridge and lip mucosa, it is a potential gap.
42. Median position: When the mandibular condyle is located in the physiological posterior position of the joint cavity and the surrounding tissues are not restricted, it is called median position.
43. Resting jaw position: when the natural dentition exists, when the mouth does not chew, swallow or speak, the lower jaw is in a resting state, and the upper and lower dentition are naturally separated without jaw contact, which is called resting jaw position. At this time, the gap between the upper and lower dentition is called resting jaw space.
44. Vertical distance: When the natural dentition is in the middle jaw, the distance from the base of nose to the base of condyle is one third of the distance under the face. 45. Condylar canal: the path of condyle movement in the joint cavity during mandibular mastication.
46. Incision: When the mandible moves forward from the middle occlusion, the path that the edge of mandibular incisor moves forward and downward along the front surface of maxillary tongue is called incision, and the angle between incision and the plane of orbital ear is called incision inclination.
47. Grinding selection: adjust the early contact point of the middle jaw to make the middle jaw reach extensive and uniform contact and stable cusp-socket relationship, and adjust the cusp interference between the lateral jaw and the protrusive jaw to achieve balanced jaw contact.
48. Re-lining: A layer of plastic is added to the tissue surface of the complete denture to fill the gap between the alveolar ridge and the surrounding tissue absorption part, so that the tissue surface of the base is closely attached to the surrounding tissue and the retention force of the denture is increased.
49. Buccal marginal area (Buccal shed area): It is located in the posterior dental arch area of mandible, between the buccal ligament of mandible and the anterior edge of the lower masseter. When the alveolar ridge of the posterior mandible is absorbed into a low flat shape, this area is also called Buccal shed area 50. The mastoid process of incisors is an important and stable sign of maxilla. Located in front of the maxillary palatine suture, on the palatal side of the upper central incisor, it is pear-shaped, oval or irregular soft tissue protrusion. Below the mastoid is the mastoid of the incisors.
5 1, tremor line: located at the junction of soft palate and hard palate. When the patient makes a whoop, this part trembles slightly, so it is also.
The symmetry line can be divided into two parts: the front tremor line and the back tremor line. The anterior tremor line is at the junction of hard palate and soft palate, about on the line between pterygomaxillary notch and palatal recess. The dorsal tremor line is at the junction of the aponeurosis and the muscle of the soft palate.
52. Posterior molar pad: It is a kind of mucosal soft pad, which is located at the distal end of the alveolar ridge of the last mandibular molar. It is round, oval or pear-shaped, covering the posterior triangle of molars. It consists of loose connective tissue and contains mucus glands.
53. Christensen's phenomenon: After the upper and lower occlusal supports are placed in the mouth, the patient's jaw is required to extend forward about 6 mm. When the lower occlusal support is closed, the leading edge of the occlusal support contacts and the rear part leaves, forming a wedge-shaped gap. When this gap is positively correlated with the inclination of condyle, the greater the positive correlation, the greater the wedge-shaped gap. This phenomenon is called ~
54. Balanced jaw of complete denture: refers to the balanced jaw, which can contact at the same time when performing non-central movement, such as forward extension and lateral movement.
55. Condylar inclination angle: refers to the angle between the condylar groove and the horizontal plane, which is recorded by transferring the condylar inclined plane to the closed frame through the protrusive relationship. 56. Guide inclination: refers to the angle between the cutting guide disc and the horizontal plane, and the cutting guide inclination is equal to but not equal to the cutting slope.
57.monson curvature: monson referred to in complete denture restoration is mostly confined to the joint of upper 3- upper 7 buccal canines, forming a downward convex curve.
58. Maxillary frame: The upper and lower models supported by the upper and lower jaws are fixed on the jaw frame with plaster to maintain the height and jaw position of the upper and lower models.
59. Overdenture: refers to a complete or removable partial denture covered by denture base and supported by natural teeth, treated roots or implants. 60. Immediate complete denture: It is a kind of denture made in advance before the patient's natural tooth is extracted and put on immediately after tooth extraction. 6 1, positioning mode: denture positioning has a certain direction and angle, and the way to position denture along this direction is 62. Porcelain-fused-to-metal crown: it is a kind of metal-ceramic composite structure restoration with low melting point porcelain fused to cast metal-based crown under vacuum condition. 63. Dental colorimetry: refers to the process of comparing the color cards of different colors on the colorimeter with the natural teeth left in the mouth, selecting the closest color, recording the results and sending them to the technician.
64. Try-on of porcelain crown: refers to the try-on of metal substrate or the oral fit of porcelain crown before glazing, which is an important link before restoration is completed.
Questions and answers:
Brief introduction of advantages and disadvantages of 1 removable partial denture
Answer:
A. wide range 10%
B. 10% of the tooth tissue was removed.
C. You can take it off and wear it yourself 10%
Maintain good oral hygiene 10%
E simple manufacturing method 10%
F lower cost, 10%
G easy maintenance 10%
H foreign body sensation in large volume 10%
1. Poor production quality 10%
It is difficult to maintain oral hygiene 10%
Advantages: Removable partial denture is one of the most commonly used methods in dentition defect repair. Besides wide application range, it also has the advantages of less dental tissue, easy cleaning and cleaning to maintain good oral hygiene, simple manufacturing method, low cost and easy repair and supplement.
Disadvantages: Removable partial dentures are bulky and have many parts. When wearing it for the first time, patients often feel foreign body sensation, which sometimes affects pronunciation and causes nausea. Their stability and chewing efficiency are not as good as fixed dentures. If the denture design is unreasonable, the manufacturing quality is poor or it is difficult for patients to maintain oral hygiene, it may also bring adverse consequences to patients, such as abutment injury, mucosal ulcer, plaque formation and tartar accumulation, dental caries and periodontitis, accelerated alveolar ridge absorption, temporomandibular joint diseases and so on.
Question type: question and answer
2 Briefly describe the types of removable partial dentures
Answer:
A.30% of supported dentures
B. Mucosal supporting denture 30%
C. Mixed denture 40%
According to the supporting tissues of dentures, removable partial dentures can be divided into the following three types.
Dental supporting denture
Brace and clasp are placed on abutment teeth at both ends, and the resultant force of denture is mainly borne by natural teeth; Suitable for a small number of missing teeth, or the gap between missing teeth is small, and there are abutments at both ends of the gap, and the abutments are stable.
Mucosal supported denture
The unsupported resultant force composed only of base, denture and clasp is directly transmitted to mucosa and alveolar bone through base; It is suitable for those who have most teeth missing, the remaining teeth are loose, or the bite is too tight to grind the supporting position.
Mixed supported denture
The abutment teeth are provided with brackets and snap rings, and the brackets are fully stretched, so that the natural teeth and mucosa can bear together; It is suitable for all kinds of dentition defects, especially those with missing free end. This is the most commonly used form in clinic.
Question type: question and answer
3 Various parts of removable partial dentures can be divided into several categories according to their functions.
Answer:
A. Repair defects and restore 30% of functional parts.
B. 30% of the reserved and stable part
C. Connect the force transmission part by 40%
Each part of the removable partial denture has its primary and secondary functions, and each part can play a synergistic role. According to its functions, it can be summarized into the following three parts:
Repair defects and restore functions: dentures, bases and supports.
Reservation and stability: all kinds of direct reservation, indirect reservation, foundation and support.
Connecting and transmitting parts: base, connector, connecting rod and bracket.
Question type: question and answer
4. Briefly describe the basic requirements of removable partial denture design.
Answer:
A. restore masticatory function 10%
B. Protection of oral tissue health 10%
C. Good retention and stability 20%
D. Comfort 20%
E. Beautiful and durable, 20%
F.20% easy to take off and put on.
1. properly restore chewing function.
2. Protect the health of oral tissues
3. Dentures should have good retention and stability.
comfortable
beautiful
6. Strong and durable
7. Easy to take off and wear
Question type: question and answer
5. Briefly describe the characteristics of RPI of removable partial denture.
Answer:
A. the torque of the tooth root is reduced by 25%.
B. antagonistic 25%
C. Torque reduction by 25%
D. The contact area is reduced by 25%.
Answer: After the saddle base is loaded, the I-bar leaves the abutment surface and the adjacent plate moves down, which reduces the torque to the abutment.
The antagonism between the small connector and the abutment surface of the mesial occlusal support ensures the interaction of the clasp when the denture is worn, and it is not necessary to design the level of the lingual resistance arm.
The torsion of mesial occlusal support on abutment is small;
The contact area between I-beam and tooth surface is small and beautiful. Aiming at the weakness of poor stability of I-beam, the adjacent panels with strong stability are designed.
Question type: question and answer
6. Briefly describe the function of occlusal support.
Answer:
A. Supporting role 25%
B. Stabilize 25%
C. Prevent food blockage by 25%
D. restore 25% occlusion.
Occlusal support is the part of the clasp body extending to the occlusal surface of abutment, which has high strength. Its main function is to prevent the denture from moving longitudinally, play a supporting role, and make the occlusal force transfer to the abutment direction. Occlusal support also has a certain stabilizing effect. In addition, the occlusal support is also used to prevent food from being blocked, and the enlarged occlusal support is used to restore the occlusal relationship with poor occlusal relationship.
Question type: question and answer
What is the relationship and difference between the components of articulator and the corresponding organs of human body?
Answer:
A The mandible is equivalent to 25% of the mandible of the articulator.
B the maxilla corresponds to 25% of the maxilla of the articulator.
C. The rising support corresponds to 25% of the outer bolts on the articulator.
D condyle. The articular cavity corresponds to 25% of the condylar ball and condylar groove on the articulator.
The articulator is an instrument that simulates the structure and function of the human chewing tube, and consists of components corresponding to the human structure: the maxillary bone on the human body corresponds to the maxillary body of the articulator; The mandible on the human body corresponds to the mandibular body of the occlusal frame; The mandibular ramus on the human body corresponds to the lateral bolt on the occlusal frame; A joint in the human body. The joint cavity corresponds to the condylar ball and condylar groove on the articulator; The imaginary connecting line between the left and right condyles of human body corresponds to the condyle strip on the articulator; The facial skin surface corresponding to condyle on human body corresponds to the outer end of condyle strip on articulator; The incision on the human body corresponds to the incision guide on the articulator; The inclination of the incision on the human body corresponds to the inclination of the incision guide on the articulator; The condylar canal on the human body corresponds to the condylar guide on the occlusal frame; The inclination of the human internal condyle corresponds to the inclination of the condyle guide rail on the articulator, and it is different from the chewing organ in the direction of movement and structural connection: when the articulator is opened, the human internal maxilla is upward and the maxilla is downward; When the mandible is extended forward on the occlusal frame, the maxillary body in the human body is backward and the upper and lower jaws are forward; When the upper side of the articulator is engaged, the maxillary body in the human body moves backwards and the upper and lower jaws move forward;
Question type: question and answer
How to ensure the stability of implant denture
Answer:
A. The greater the deviation, the worse the stability, which is 40%.
B. If the abutment of the implant is well preserved, the stability will reach 30%.
C the longer the cantilever, the worse the stability is 30%.
Stability is related to whether the implant denture produces a large lever force when it bears the occlusal force, and the lever force is related to the structural design of the implant denture.
The connecting line of implant abutment forms a baseline, and the fulcrum line of fixed implant denture can be a straight line, a triangle or a quadrilateral supporting surface, and the latter two have good stability.
The factors affecting its stability are: the relationship between the bridge body of two implant abutments and the position of the fulcrum line, when the center of the bridge body is located on the fulcrum line, the stability is better; When the center of the bridge is located at one side or in front of the fulcrum line, the greater the deviation, the worse the stability; (2) Implanted dentures with multiple implant abutments have triangular or quadrilateral supporting surfaces, and the stability is excellent as long as the implant abutments are kept well; (3) When designing single-ended bridge, the length of cantilever affects the stability of implant denture. The longer the cantilever, the worse the stability, which is also extremely unfavorable to retention.
Implant abutments of removable implant dentures are distributed in triangle or quadrilateral as far as possible, so that the center of implant dentures is close to or consistent with the center of attachment line of implant abutments. Removable implant dentures have attachments or magnets to increase retention, thus greatly improving the stability of implant dentures. When the removable implant denture has free abutment, it has certain influence on its stability.
Question type: question and answer
What are the requirements for the metal base of PFM crown?
Answer:
A. an adequate retention rate of 20%
B. Thickness and strength 20%
C.20% has no sharp edges and corners.
D.20% uniform thickness
E. Smooth without sharp edges 20%
Metal-based low crowns, even porcelain brackets, bear and transmit bite force, and also have retention function, which involves aesthetics. The quality of the combination of bite and porcelain should meet the following requirements:
Covering the crown surface of the affected teeth in the form of a full crown can provide sufficient retention.
The metal substrate has a certain thickness and strength. The thickness of precious metal substrate is generally 0.2mm~0.5mm, and the minimum thickness of non-precious metal substrate is 0.5mm, and appropriate space is provided for the porcelain layer to ensure the strength and beauty of porcelain bonding.
There are no sharp edges and sharp edges on the surface of the metal substrate, and all axial surfaces are streamlined to prevent stress concentration from damaging the combination of metal and porcelain.
Make sure the thickness of the porcelain layer is even as much as possible, and avoid sudden change in thickness, otherwise it will easily crack the porcelain.
The neck edge should be smooth without sharp edges.
Question type: question and answer
10. What are the functions of removable partial denture base?
Answer:
A. conduct and disperse 25% bite force.
B. Connect 25%
C. restore 25% appearance and beauty
D. It can improve the retention and stability of denture by 25%.
Denture devices are provided to connect, conduct and disperse tooth forces.
Connect all the parts of the denture together to form a functional whole.
It can be used to repair the hard tissue and soft tissue of alveolar ridge and restore its appearance and beauty.
It can enhance the retention and stability of denture, and also has the function of indirect retention, which can resist the displacement force of denture.
Question type: question and answer
1 1. What are the methods to determine the jaw position relationship with removable partial dentures?
Answer:
A. The model uses the remaining teeth to determine 40% jaw position relationship.
B. Determine the relationship between maxilla and mandible by wax occlusion records.
C, use occlusal dike to record 30% of the relationship between maxilla and mandible.
On the model, the relationship between maxilla and mandible is determined by using the remaining teeth.
Using wax occlusion records to determine the relationship between maxillary and mandibular positions
Recording the relationship between maxilla and mandible with occlusal pad
Question type: question and answer
12. Briefly describe the functions of temporary bridges.
A:
A. protecting movable teeth 10%
B. Restore 20% partial chewing
C. keep the dental arch stable by 20%.
D, maintaining the aesthetic effect of the front teeth by 20%
E. prevent abutment from accidental fracture by 20%
F adapt to the shape and function of the fixed bridge after repair 10%
Protect the grinding surface of movable teeth from allergies and avoid irritation and pollution.
Restore partial chewing. Voice function
Maintain the position of edentulous space and the stability of dental arch.
Maintain the aesthetic effect of the front teeth.
Prevent accidental fracture of abutment
Let patients adapt to the shape and function of the fixed bridge after repair.
Question type: question and answer
13. What are the methods to determine the vertical distance of complete denture?
A: How to determine the vertical distance.
Rest occlusal gap method 25%
B facial contour method 25%
C-plane proportional method 25%
D reference original denture 25%
Other occlusal clearance methods: in natural dentition, the upper and lower dentition are not in contact. The position of the mandible at rest is called the rest position. The gap between the upper and lower dentition at rest is the rest occlusal gap. The average gap is 2 mm, and the vertical distance of complete denture can be obtained by subtracting 2 mm from the distance between nose base and chin base at rest.
The vertical distance 1/3 under normal face shape is basically in harmony with facial appearance. At this time, the facial expression is natural, the upper and lower lips can be closed naturally, and the mouth has no obvious drooping or lifting, which can be used as a reference for determining the vertical distance.
Face proportion method: when the eyes are flat, the distance from the pupil line to the cleft of the mouth is equal to the distance from the base of the nose to the base of the chin.
Refer to the records before tooth extraction: During the middle occlusion before tooth extraction, measure and record the distance from the base of nose to the base of chin as a reference for determining the height during restoration.
Reference to the original denture: If the patient has worn a denture, the vertical distance can be determined with reference to the denture.
Question type: question and answer
14. What are the horizontal distance methods to determine the jaw position of complete denture?
A. Gothic architecture accounts for 40%.
B. Direct bite method 30%
C. Monitoring method 20%
Gothic bow drawing
Gothic extraoral dental arch tracing method, when determining the jaw position relationship, a handle with a length of about 2 mm is installed in front of the upper and lower occlusal supports, and the handle end of the upper jaw has a tracing needle perpendicular to it, and the lower jaw has a tracing plate opposite to the needle extending forward. When moving laterally, the tracing needle fixed on the upper jaw draws an approximate "A" shape on the tracing board of the lower jaw, that is, when the tracing needle points to the vertex of the figure, the lower jaw is in the middle position.
Direct bite method is a method to guide the patient's mandible to retreat and bite together directly by using the recording materials of occlusal dike and jaw. Patients with edentulous jaws are habitually elongated, and the following methods are needed to help them retreat to the middle position and bite together.
Back rolling tongue method
Swallow and bite
Back biting method
Monitor The muscle monitor can emit a small amount of direct current, which acts on the motor branch of trigeminal nerve through the body surface electrode attached to the front of the earlobe about 4cm up and down, so that the masticatory muscle contracts rhythmically, which can relieve the fatigue and tension of the muscle and make it in a natural state. For those who have long been edentulous and have bad occlusion habits, the mandible can naturally retreat to its physiological posterior position after using muscle monitor and direct occlusion treatment.
The direct bite method is simple to operate and suitable for experienced doctors. However, the wax occlusal dike needs to be adjusted to a suitable height to avoid the increase of oral mucosal load in a certain area, which will lead to mandibular deviation. At the same time, because doctors are involved in promoting mandibular recession, improper force will have incorrect consequences.
Question type: question and answer
15. What are the requirements before bonding porcelain crowns?
Answer:
A.20% of prostheses are made perfectly.
B. Arrive at the correct position by 20%
C. Good occlusion 20%
D. Good neck edge and shape 20%
E. Feel comfortable 10%
F. Disinfection 10%
(1) The prosthesis is well-made, without defects, trachoma, shrinkage cavity, etc. The appearance should be smooth, the joint surface should be clean, and the metal tumor and gypsum powder should be removed.
(2) The prosthesis should be in place on the prepared teeth, and can reach the correct position and close the neck edge, with low occlusion, good retention and no warping.
(3) The prosthesis achieves a good occlusion: the anterior teeth do not contact in the middle occlusion, and the posterior teeth are in close contact with the cusp and sulcus ridge; The working surface is in contact, but the balance surface is not. No early contact and high points.
(4) Good neck edge and shape: the neck edge is tight without gaps, steps and overhangs; The shape of teeth conforms to the normal shape of teeth, without convexity or lack of physiological convexity; Adjacent surfaces are in close contact without gaps, and the contact area is in a normal position; The occlusal surface has a good shape, its size is suitable for periodontal endurance, and it can form a good occlusion with occlusal teeth.
(5) Patients are satisfied with the shape and color of the prosthesis and feel comfortable.
(6) The corrected teeth should be polished or glazed, and the cemented surface should be disinfected with 75% alcohol before cementation.
Question type: question and answer
16 brief introduction of porcelain-fused-to-metal full crown covering design?
Answer:
A. 50% coverage of all porcelain surfaces
B. 50% coverage of some porcelain surfaces.
(1) All porcelain surfaces are covered with porcelain layers, and all porcelain layers are covered with metal bases, which are suitable for normal occlusion of anterior teeth.
(2) The porcelain surface partially covered with porcelain only covers the labial surface of the crown, and the lingual surface is mostly metal, which is suitable for patients with tight occlusion, deep coverage and large resultant force.
Question type: question and answer
17 Briefly describe the principle of tooth preparation.
Answer:
A. Closing the 20% gap
B. Protect the pulp by 20%
C, removing 20% of dental caries tissue.
D, remove that undercut which prevents the prosthesis from bee in place. E. the polymerization degree of 20% is generally not more than 8 10%.
F periodontal tissue and protection of periodontal tissue 10%
Accurate, harmless and effective tooth preparation is an important link to coordinate the shape of prosthesis with natural teeth and dentition. Therefore, tooth preparation should be carried out according to the principles of prosthodontics and biomechanics.
(1) On the premise of retaining the tooth tissue as much as possible, polish the tooth tissue as accurately and evenly as possible according to the requirements of retention, support, resistance, beauty and normal appearance design, and open up the necessary restoration gap.
(2) Pay attention to the correct selection of equipment in tooth preparation and take cooling protection measures to protect dental pulp.
(3) Cleaning the dental caries tissue and enamel without dentin support)
(4) remove that undercut that prevents the restoration from bee in place, and remove the sharp edges and corners on the tooth preparation surface that may cause wear or stress concentration.
(5) Generally, the polymerization degree of the axial wall is not greater than 8, and the cavity wall is flared ≦ 10, which meets the requirements of retention and positioning.
(6) Pay attention to protecting periodontal tissue and periodontal tissue during tooth preparation.
Question type: question and answer
What problems should be paid attention to in the design of 18 fixed bridge retainer?
Answer:
Maintain form and resistance by 20%
Similarly, B*** 20%.
C holder shape 20%
The marginal fitness of D retainer is 20%.
E material characteristics protect the health of soft and hard tissues of teeth by 20%
(1) Retention form and resistance retainer should have good retention form and resistance form, and can resist external force without loosening, falling off and damage during functional movement.
(2) The * * * co-located road can obtain the * * * co-located road needed for fixing the bridge.
(3) The shape of retainer can restore the anatomical shape, physiological function and aesthetic requirements of abutment, and it has good self-cleaning effect.
(4) The edge of the retainer must be closely attached to the abutment preparation surface, and the adhesive with good adaptability is not exposed to the mouth. The edge of the retainer is continuous with the adjacent tooth surface and does not stimulate soft tissue.
(5) The materials used in the material property retainer have good processability, mechanical strength, biocompatibility and chemical stability.
(6) Protection of tooth hardness. Soft tissue retention can protect the health of teeth, pulp and periodontal tissues, so that abutment teeth will not be broken by external force, maintain pulp vitality and prevent periodontal disease due to restoration.
Question type: question and answer
19 on the function of removable partial denture with large joint.
Answer:
A. Full 40%
B the combined force of conduction and diffusion is 40%
C, reducing the denture volume by 20%
(1) Connect the denture components to form a whole.
(2) Conducting and dispersing the resultant force to other abutments and adjacent supporting tissues.
(3) Compared with base connection, it can reduce the size of denture and increase the strength of denture.