Dental Materials and Techniques
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Questions and Answers

Which material should not be used together with polyvinyl siloxane elastomeric impression material due to its ability to retard the setting?

  • Sulfide (correct)
  • Silver nitrate
  • Ferric sulfate
  • Aluminum chloride
  • What is the main function of the chemical agents used in conjunction with gingival cords?

  • Decrease the leaking of crevicular fluid (correct)
  • Facilitate tooth preparation
  • Prevent gingival recession
  • Promote tissue shrinkage
  • Which chemical agent has been the most popularly used with retraction cords but its use for this purpose has decreased over time?

  • Zinc chloride
  • Epinephrine (correct)
  • Aluminum chloride
  • Ferric sulfate
  • What are the systemic effects associated with the use of epinephrine-soaked retraction cords?

    <p>Tachycardia and increased blood pressure</p> Signup and view all the answers

    Which agent commonly causes the removal of smear layer if placed for more than 10 minutes, leading to potential sensitivity in patients after the procedure?

    <p>Ferric sulfate</p> Signup and view all the answers

    Which agent has limited use in gingival retraction methods due to being less effective at controlling haemorrhage and crevicular exudates?

    <p>Aluminum chloride</p> Signup and view all the answers

    What is the wavelength of commonly used diode lasers?

    <p>980 nanometers (nm)</p> Signup and view all the answers

    Why is electrosurgery not recommended as a method for gingival retraction?

    <p>It generates heat that may cause osseous or mucosal necrosis</p> Signup and view all the answers

    What is the main factor influencing the quality of the marginal fit of a restoration?

    <p>Location of the finish lines</p> Signup and view all the answers

    What is the purpose of gingival retraction in fixed prosthesis treatment?

    <p>To enhance aesthetics and longevity of restorations</p> Signup and view all the answers

    What is the definition of gingival retraction?

    <p>The process of deflection of the marginal gingiva away from a tooth</p> Signup and view all the answers

    Why is it important to consider subgingival margins for restorations placed close to the soft tissues?

    <p>To avoid failure of subsequent restorations</p> Signup and view all the answers

    How do periodontal factors influence the quality of the marginal fit of a restoration?

    <p>By influencing sulcus bleeding during impression making</p> Signup and view all the answers

    What is the significance of keeping the health of the gingiva and periodontium in consideration during procedures?

    <p>To ensure aesthetics and longevity of restorations</p> Signup and view all the answers

    What can be stated about restorations placed in close proximity to soft tissues?

    <p>They may have a high chance of failure without subgingival margins</p> Signup and view all the answers

    Why is a good quality impression influenced by periodontal health?

    <p>To prevent sulcus bleeding during impression making</p> Signup and view all the answers

    What is the primary purpose of retraction cords in dentistry?

    <p>To facilitate impression making by displacing the gingival tissue</p> Signup and view all the answers

    Why is it important for retraction cords to be biocompatible and non-toxic?

    <p>To avoid causing damage to the supporting tissues</p> Signup and view all the answers

    What is the main disadvantage of using retraction cords?

    <p>They can be painful and uncomfortable for the patient</p> Signup and view all the answers

    What is the purpose of utilizing the double-cord technique in dental retraction?

    <p>To achieve additional displacement of the gingival tissues</p> Signup and view all the answers

    Why is it important to use minimal force when inserting retraction cords?

    <p>To prevent damage to the periodontal attachment fibers</p> Signup and view all the answers

    What is the recommended time range for placing retraction cords in the gingival sulcus?

    <p>1–30 minutes</p> Signup and view all the answers

    What advantage does the Stay-put retraction cord offer over traditional retraction cords?

    <p>It maintains its shape and can be pre-shaped</p> Signup and view all the answers

    How does the use of rubber dam contribute to dental procedures?

    <p>It aids in isolating and protecting the gingival tissues</p> Signup and view all the answers

    What is the primary purpose of gingival retraction during impression taking?

    <p>To provide access for impression material beyond the abutment margins and create space for the impression material</p> Signup and view all the answers

    Why is it important to assess the gingival tissues before considering any retraction?

    <p>To identify if the tissues are already compromised and can be further damaged by retraction methods</p> Signup and view all the answers

    What is the role of clinical assessment in evaluating the gingival tissues?

    <p>To evaluate consistency, pain, and bleeding on probing of the gingival tissues</p> Signup and view all the answers

    Why is it recommended to place restoration margins 0.5−1mm below the gingival margin?

    <p>To avoid encroaching on the epithelial and connective tissue attachment</p> Signup and view all the answers

    What is a limitation of the chemo-mechanical technique for gingival retraction?

    <p>It requires local anesthesia and may cause injury to epithelial tissue and gingival recession</p> Signup and view all the answers

    What is the primary purpose of mechanical retraction techniques?

    <p>To physically retract and displace the soft tissues, providing haemostasis and controlling crevicular fluid</p> Signup and view all the answers

    What aspect of assessment do radiographs help in evaluating?

    <p>Interproximal bone levels, crestal bone height, infra-bony pockets, and boss loss</p> Signup and view all the answers

    Why is it important to minimize or avoid bleeding on probing while assessing gingival tissues?

    <p>To indicate healthy gingiva that is less likely to get damaged during retraction</p> Signup and view all the answers

    Which material is composed of Aluminum chloride, Kaolin, and Excipicent?

    <p>Gingival Retraction Paste</p> Signup and view all the answers

    What is the least irritating hemostatic agent that may be left in the sulcus for up to 15 minutes without causing any permanent damage?

    <p>Aluminum chloride</p> Signup and view all the answers

    Which hemostatic agent causes actual shrinkage of the tissues?

    <p>Ferric sulfate</p> Signup and view all the answers

    What is the recommended concentration of aluminum chloride and zinc chloride to prevent caustic effects on gingival tissues?

    <p>Low concentration</p> Signup and view all the answers

    Which material is often used along with gingival retraction cords to effectively control bleeding?

    <p>Racemic epinephrine</p> Signup and view all the answers

    Which substance is used in Expasyl to provide mild displacement of the gingiva within two minutes upon contact with crevicular fluid?

    <p>Aluminum chloride</p> Signup and view all the answers

    What is the main advantage of using Expasyl for gingival retraction?

    <p>Avoids gingival recession or bone resorption</p> Signup and view all the answers

    What undesirable side effects may epinephrine produce when used along with gingival retraction cords?

    <p>Tachycardia and increased respiratory rate</p> Signup and view all the answers

    What is the primary purpose of gingival retraction in fixed prosthesis treatment?

    <p>To create space for impression materials and to ensure accurate impressions are obtained.</p> Signup and view all the answers

    Why is it important to consider subgingival margins for restorations placed close to the soft tissues?

    <p>To prevent failure of subsequent restorations.</p> Signup and view all the answers

    What is the main function of the chemical agents used in conjunction with gingival cords?

    <p>To control hemorrhage and crevicular exudates.</p> Signup and view all the answers

    What can be stated about restorations placed in close proximity to soft tissues?

    <p>They may require consideration of subgingival margins.</p> Signup and view all the answers

    What is the main disadvantage of using retraction cords?

    <p>They may cause damage to the gingival tissues if used improperly.</p> Signup and view all the answers

    What is the primary purpose of retraction cords in dentistry?

    <p>To displace the marginal gingiva and create space for impression materials.</p> Signup and view all the answers

    What is a limitation of the chemo-mechanical technique for gingival retraction?

    <p>It may not be effective in all clinical situations.</p> Signup and view all the answers

    Why is a good quality impression influenced by periodontal health?

    <p>Periodontal health affects the location of finish lines and the quality of the impression.</p> Signup and view all the answers

    What are the four forces that act on the gingival tissues during gingival retraction?

    <p>Retraction, displacement, relapse, collapse</p> Signup and view all the answers

    What are the two variations of gingival biotypes and how do they influence treatment planning?

    <p>Thick and thin biotype; Thin biotypes are more likely to be adversely affected with a subgingivally placed restoration and hence, the treatment and restoration should be planned accordingly.</p> Signup and view all the answers

    What parameters should be assessed to evaluate the placement of restoration margins?

    <p>Gingival indices, gingival sulcus, bleeding on probing, peri-apical and bitewing radiographs</p> Signup and view all the answers

    What are the three principal methods available for soft tissue retraction?

    <p>Mechanical, chemo-mechanical, electrosurgical</p> Signup and view all the answers

    What are the limitations of the chemo-mechanical technique for gingival retraction?

    <p>Time consuming, painful, need for local anesthesia, injury to epithelial tissue, gingival recession</p> Signup and view all the answers

    What clinical assessments should be performed prior to retracting or displacing the gingival tissue?

    <p>Assessment of gingival tissues' color, firmness, biotype, contour, consistency, pain, bleeding on probing, and use of gingival indices</p> Signup and view all the answers

    What radiographic assessments can be utilized to evaluate interproximal bone levels and crestal bone height?

    <p>Peri-apical and bitewing radiographs</p> Signup and view all the answers

    What methods can be used to control crevicular fluid during direct composite restoration placement or cementation of deep subgingival indirect restorations?

    <p>Mechanical retraction techniques</p> Signup and view all the answers

    What are the ideal properties of retraction cords?

    <p>Biocompatible, non-toxic material; ability to absorb blood, crevicular fluids and medicaments; easy to apply and remove; contrasting colour with the surrounding tissue; does not cause damage to the supporting tissues</p> Signup and view all the answers

    What is the recommended time range for placing retraction cords in the gingival sulcus?

    <p>1–30 minutes</p> Signup and view all the answers

    What is the main function of the chemical agents used in conjunction with gingival cords?

    <p>Controlling haemorrhage and crevicular exudates</p> Signup and view all the answers

    Why is it important to minimize or avoid bleeding on probing while assessing gingival tissues?

    <p>Bleeding on probing can interfere with the assessment and may lead to inaccurate evaluation of the gingival tissues.</p> Signup and view all the answers

    What is the primary purpose of mechanical retraction techniques?

    <p>To displace the gingival tissue and achieve adequate exposure of the tooth preparation margins for impression making</p> Signup and view all the answers

    What is the main disadvantage of using retraction cords?

    <p>They can be painful and uncomfortable for the patient, and the sulcus collapses soon after the removal of the cord.</p> Signup and view all the answers

    What advantage does the Stay-put retraction cord offer over traditional retraction cords?

    <p>It maintains its shape once inserted inside the gingival sulcus, and its pliability makes it easier to place in the sulcus.</p> Signup and view all the answers

    What is the significance of keeping the health of the gingiva and periodontium in consideration during procedures?

    <p>It helps to avoid potential damage to the gingival tissue, disruption in blood supply, and damage to the periodontal attachment fibers.</p> Signup and view all the answers

    What are the three broad classifications of gingival retraction materials based on the method of application?

    <p>gingival hemostatic agents, gingival retraction cord/caps, gingival retraction paste/gels</p> Signup and view all the answers

    What is the recommended concentration of racemic epinephrine in epinephrine-impregnated retraction cords?

    <p>8 percent</p> Signup and view all the answers

    Which material is Expasyl composed of?

    <p>Aluminum chloride, Kaolin, Excipicent</p> Signup and view all the answers

    What are the undesirable side effects that epinephrine may produce when used along with gingival retraction cords?

    <p>tachycardia, increased respiratory rate, hypertension, nervousness, feelings of weakness in the extremities, frank apprehension, post-operative depression</p> Signup and view all the answers

    What is the main advantage of using Expasyl for gingival retraction?

    <p>mild displacement of the gingiva within two minutes upon contact with crevicular fluid</p> Signup and view all the answers

    Which hemostatic agent is least irritating and may be left in the sulcus for up to 15 minutes without causing permanent damage?

    <p>Aluminum chloride</p> Signup and view all the answers

    What are the three components of Expasyl?

    <p>Aluminum chloride, Kaolin, Excipicent</p> Signup and view all the answers

    What is the role of epinephrine in controlling bleeding when used with gingival retraction cords?

    <p>effectively control bleeding</p> Signup and view all the answers

    What are the potential systemic effects associated with the use of epinephrine-soaked retraction cords?

    <p>Tachycardia, increased blood pressure, nervousness, anxiety, increased respiration, and post-operative depression</p> Signup and view all the answers

    What is the wavelength of commonly used diode lasers?

    <p>980 nanometers (nm)</p> Signup and view all the answers

    What is the main disadvantage of using ferric sulfate as a coagulant for gingival displacement?

    <p>It can cause sensitivity in patients after the procedure and interfere with impression setting and bonding of composite to the tooth</p> Signup and view all the answers

    What undesirable side effects may epinephrine produce when used along with gingival retraction cords?

    <p>Tachycardia, increased blood pressure, nervousness, anxiety, increased respiration, and post-operative depression</p> Signup and view all the answers

    What are the potential systemic effects associated with the use of epinephrine-soaked retraction cords?

    <p>Tachycardia, increased blood pressure, nervousness, anxiety, increased respiration, and post-operative depression</p> Signup and view all the answers

    What is the primary purpose of using retraction cords in dentistry?

    <p>To physically displace the gingival tissues for retraction and to control bleeding and crevicular fluid</p> Signup and view all the answers

    What is the primary purpose of mechanical retraction techniques?

    <p>To provide retraction of gingiva and isolation for restorations</p> Signup and view all the answers

    What is the recommended concentration of aluminum chloride and zinc chloride to prevent caustic effects on gingival tissues?

    <p>20-25% for aluminum chloride and 8% or 40% for zinc chloride</p> Signup and view all the answers

    The aesthetics and longevity of restorations is significantly dependent on ______ and periodontal factors.

    <p>gingival</p> Signup and view all the answers

    The intimate interaction between the restorations and the surrounding soft tissues means that all procedures performed should keep the health of the ______ and periodontium under consideration.

    <p>gingiva</p> Signup and view all the answers

    Restorations placed in close proximity to the soft tissues sometimes require consideration of ______ margins, otherwise the subsequent restorations may have a high chance of failure.

    <p>subgingival</p> Signup and view all the answers

    The retraction of the ______ tissue is a long established technique. It can be defined as the process of deflection of the marginal gingiva away from a tooth.

    <p>gingival</p> Signup and view all the answers

    Periodontal factors influence the quality of the marginal fit of a ______.

    <p>restoration</p> Signup and view all the answers

    A good quality impression is influenced by location of finish lines, periodontal health and sulcus bleeding during ______ making.

    <p>impression</p> Signup and view all the answers

    The intimate interaction between the restorations and the surrounding soft tissues means that all procedures performed should keep the health of the ______ and periodontium under consideration.

    <p>gingiva</p> Signup and view all the answers

    The aesthetics and longevity of restorations is significantly dependent on gingival and ______ factors.

    <p>periodontal</p> Signup and view all the answers

    Tear resistance of the impression material can be affected by the material ______.

    <p>thickness</p> Signup and view all the answers

    Impression with less sulcular width have higher incidences of voids, tearing of impression materials and reduction in ______ accuracy.

    <p>marginal</p> Signup and view all the answers

    Retraction is the downward and outward force exerted on the gingival tissues by the retraction technique or ______.

    <p>material</p> Signup and view all the answers

    The gingival biotype should be identified, which is a useful indicator of the behaviour of the gingiva to operative procedures and gingival ______.

    <p>displacement</p> Signup and view all the answers

    Margins placed too deep in the sulcus require more retraction of the gingival tissue, resulting in damage to the supporting structures of the ______.

    <p>tooth</p> Signup and view all the answers

    The chemo-mechanical technique is probably the most widely used but its limitations are time consuming, painful, need for local anesthesia and injury to epithelial tissue and gingival ______.

    <p>recession</p> Signup and view all the answers

    For the retraction of soft tissue, three principle methods are available for use today: 1) mechanical; 2) chemo- mechanical; and 3) ______.

    <p>electrosurgical</p> Signup and view all the answers

    These techniques involve physically retracting and displacing the soft tissues, making space for the impression material to reach the recess of the subgingival preparation, as well as providing haemostasis and controlling crevicular fluid during direct composite restoration placement or cementation of deep subgingival indirect ______.

    <p>restorations</p> Signup and view all the answers

    Gingival retraction materials can be broadly classified into three groups based on the method of application: ______ hemostatic agents, ______ retraction cord/caps and ______ retraction paste/gels of the material.

    <p>gingival</p> Signup and view all the answers

    Astringents exert their action topically on the injured mucosal surface, whereas the hemostatic effect of vasoactive molecules is accomplished through a direct vascular action. Aluminum ______ has been found to be least irritating, and it may be left in the sulcus for up to 15 minutes without causing any permanent damage. Aluminum ______ is solid in a stable acidic buffer resulting in an etched dentine.

    <p>chloride</p> Signup and view all the answers

    Ferric ______ acts as a clotting agent, and often, when the string is removed, the clot is pulled out with it, and hemorrhage begins. Also, ferric ______ does not cause actual shrinkage of the tissues. Alum acts mainly as an astringent and is considered to be safe and moderately effective as a tissue-displacing agent.

    <p>sulfate</p> Signup and view all the answers

    Epinephrine is very commonly used along with gingival retraction cords to effectively control bleeding. The sulcus bleeding is said to be better controlled with this than astringent containing cord. Epinephrine-impregnated retraction cord contains 8 percent racemic ______. It has been shown that ______ produces a syndrome of undesirable side effects that may include tachycardia, increased respiratory rate, hypertension, nervousness, and feelings of weakness in the extremities, frank apprehension, and post-operative depression.

    <p>epinephrine</p> Signup and view all the answers

    ______ is a universally accepted and widely used gingival retraction paste. It is composed of three materials: Aluminum chloride, Kaolin and Excipicent. The product is supplied in reusable capsules. The consistency of ______ is especially formulated not to damage the healthy periodontium; the phenomena of gingival recession or bone resorption are thus avoided.

    <p>Expasyl</p> Signup and view all the answers

    On contact with crevicular fluid, this ______ provides mild displacement of the gingiva within two minutes. Expasyl, easily visible owing to its colour, is simply eliminated by an air and water spray, and a dry and widely opened sulcus is then obtained. It is painless when used on a healthy periodontium.

    <p>material</p> Signup and view all the answers

    Atraumatic gingival tissue management for impression making provides greater patient comfort during and after impression making. During restorative procedures, it is incumbent upon ______ to consider the advantages and limitations of each method in individual case and patient, and to strive for minimally invasive methods that optimize the procedural site for impression making and restoration placement.

    <p>clinicians</p> Signup and view all the answers

    The product is supplied in reusable ______. The consistency of Expasyl is especially formulated not to damage the healthy periodontium; the phenomena of gingival recession or bone resorption are thus avoided. Gingival retraction is obtained by a single application of Expasyl in the sulcus.

    <p>capsules</p> Signup and view all the answers

    According to fabrication, retraction cords can be knitted, twisted or ______ and can also be classified as impregnated or non-impregnated.

    <p>braided</p> Signup and view all the answers

    The diameter of retraction cords is usually indicated by numbers 000, 00, 0−3, to be used in different clinical situations and gingival sulcus depths. They come pre-cut or can be dispensed from a container or a ______.

    <p>clicker</p> Signup and view all the answers

    The ideal properties of retraction cords include biocompatible, non-toxic material; ability to absorb blood, crevicular fluids, and medicaments; easy to apply and remove; contrasting colour with the surrounding tissue; does not cause damage to the supporting tissues. But, cords can be painful and uncomfortable for the patient. Also, the sulcus collapses soon after the removal of the cord. Hemostasis achieved is limited and the placement of the cord in the sulcus takes time. There are two techniques for mechanical retraction, namely, single-cord and ______ technique.

    <p>double-cord</p> Signup and view all the answers

    The technique describes placing a smaller diameter cord soaked with a haemostatic agent into the depth of the sulcus, causing some lateral tissue displacement but primarily controlling haemorrhage. The second larger diameter cord is then packed into the sulcus, causing further lateral tissue displacement. The first deeper placed cord stays in place when the impression is made, after removal of the top, larger diameter ______.

    <p>cord</p> Signup and view all the answers

    Injudicious use of force during cord placement can lead to gingival recession later, due to disruption in blood supply and damage to the periodontal attachment fibres. There may be inadvertent excessive use of force while tucking the cord in the sulcus, particularly when the patient is ______.

    <p>anaesthetized</p> Signup and view all the answers

    If the retraction cord is placed for only two minutes, the sulcus width is reduced to 0.1 mm within 20 seconds of cord removal. On the other hand, if the retraction cord is placed for a longer time, this could result in damage to the gingival tissue and ______.

    <p>recession</p> Signup and view all the answers

    One product, the Stay-put retraction cord, has a thin wire incorporated into the centre of the retraction cord. Available as both plain and pre-impregnated, this cord offers the advantage of maintaining its shape once inserted inside the gingival sulcus. The pliability of the cord also makes it easier to place in the sulcus and the cord can also be pre-shaped. The pre-impregnated cord uses aluminum chloride, which diminishes the chances of cardiovascular symptoms. It comes in four sizes, according to width (0−3), and can also be used in conjunction with compression caps, which come in regular and ______ shapes.

    <p>anatomic</p> Signup and view all the answers

    The use of heavy, extra heavy and special heavy rubber dam, together with specialized clamps, help to retract and protect the gingival tissues during the preparation of the tooth as well as providing isolation for subsequent restoration placement. Inversion of the dam also aids in isolating the ______ tissues.

    <p>gingival</p> Signup and view all the answers

    Chemo-mechanical methods employ the retraction cord with the use of a chemical or a medicament. A wide variety of materials have been used in conjunction with ______ cords.

    <p>gingival</p> Signup and view all the answers

    Epinephrine has been the most popularly used chemical with which retraction cords were impregnated, although its use for this purpose has decreased overtime. It is most commonly used as 8% racemic epinephrine, but other concentrations have also been used. Retraction cords are either dipped in epinephrine or come pre-impregnated. Because of the high vascularity of the ______ tissue, the systemic effects exerted by epinephrine have been a concern when retraction cords have been lacerated.

    <p>gingival</p> Signup and view all the answers

    Ferric sulfate (15.5−20%) is commonly employed as a coagulant while performing associated gingival ______. The problems associated with using ferric sulfate is the removal of smear layer if placed for more than 10 minutes.

    <p>displacement</p> Signup and view all the answers

    Zinc chloride (bitartrate) and silver nitrate both physically cause haemostasis and precipitation of protein on the mucosal surface, resulting in ______.

    <p>coagulation</p> Signup and view all the answers

    Lasers’ properties largely depend on their wavelength and waveform characteristics. The commonly used diode lasers have a wavelength of 980 nanometers (nm). Neodymium: yttriumaluminum-garnet (Nd:YAG) lasers have a wavelength of 1064 nm. They cause less bleeding and hence the gingival retraction is minimal. Tissue shrinkage is less through scarring, which helps to preserve gingival margin heights. Visualizing the action of laser beams are difficult, owing to the plume of coolant water. Therefore, there is potential for attached gingiva to be obliterated when lasers are used for retraction purposes, since clinicians receive virtually no ______ feedback.

    <p>tactile</p> Signup and view all the answers

    An electrosurgery unit may be used for tissue removal before impression making. However, electrosurgery is not recommended as the concentrated electrical current at the tip of electrodes can generate heat, which may cause osseous or mucosal necrosis and also there is a potential for ______ recession after treatment.

    <p>gingival</p> Signup and view all the answers

    Some studies have even demonstrated that there is no significant difference in degree of retraction while using plain and epinephrine impregnated cord. Ferric sulfate (15.5−20%) is commonly employed as a coagulant while performing associated ______ displacement.

    <p>gingival</p> Signup and view all the answers

    Chemo-mechanical methods employ the retraction cord with the use of a chemical or a medicament. A wide variety of materials have been used in conjunction with ______ cords.

    <p>gingival</p> Signup and view all the answers

    Zinc chloride is available in 8% and 40% concentrations but its use has been associated with soft-tissue injury and hence is no longer recommended. Studies have described ophthalmic or nasal decongestants as potential vasoconstrictive and haemostatic agents used in conjunction with retraction cords due to their active components, like tetrahyrozoline or oxymetazoline, which are sympathomimetic amines. These are mild compounds with local vasoconstriction and minimal systemic effects. One study described them to be safer than 25% aluminum chloride for ______ cells.

    <p>epithelial</p> Signup and view all the answers

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