chapter 52 Removable Prosthodontics

Immediate Dentures

An immediate denture is a prosthesis that is placed immediately after the extraction of a patient's remaining teeth. During the healing process, this type of denture serves as a compress and bandage to protect the surgical area. Although an immediate denture may be placed in either arch, placement of a maxillary immediate denture is more common because it restores function and spares the patient the embarrassment of being without teeth. Before agreeing to receive an immediate denture, the patient must be aware that normal healing and resorption can change in the alveolar ridge. Because of these changes, the denture placed immediately after surgery must be replaced or relined in 3 to 6 months. Construction When a patient's posterior teeth have been extracted and healing is complete, but before the teeth are extracted, the try-in of the wax setup includes only the posterior teeth. These teeth are aligned in the occlusal rims and are checked for their ability to occlude with the opposing teeth. The denture, complete with anterior teeth, is constructed, sterilized, and readied for placement at surgery. Surgical Template In addition to the denture, the laboratory prepares a surgical template. The surgical template resembles a clear plastic impression tray that duplicates the tissue surface of the immediate denture. It is used as a guide for surgically shaping the alveolar process. The template helps ensure that the immediate denture will fit properly and reduce the chance of discomfort. Placement When the resulting alveolar ridge is satisfactory, the tissues are sutured into place. The sterilized denture is rinsed with saline solution and positioned in the mouth. The patient is given postsurgical instructions and home care instructions. The patient returns in 24 hours for a postoperative checkup. During this time, the denture should be worn continuously, except when it is removed for cleaning. Daily visits continue until initial healing has started and the sutures are removed, usually 48 to 72 hours after surgery. During each visit, the dentist irrigates the area with a mild antiseptic solution and checks the soft tissue for pressure points. After the sutures have been removed and the dentist and the patient are satisfied with the prosthesis, the patient is scheduled for another appointment within a few months. Overdentures An overdenture is a full denture that is supported by the bony ridge, oral mucosa, and two or more remaining natural teeth or implants. Most often, these remaining teeth are canines. Patient satisfaction with a denture is enhanced when remaining teeth or implants can improve retention and stability (see Chapter 53). Preparation and placement of the denture for use with implants and for an overdenture are similar. To permit the denture to fit snugly over the teeth without excessive bulk, the natural teeth are prepared by removing much of their bulk. The remaining tooth structure is protected with a coping. In the long coping technique, only a minimal amount of tooth structure is removed, and the length of tooth remains almost the same. In the short coping technique, which is used only with endodontically treated teeth, tooth structure is greatly reduced and shortened. The posts from an implant protrude through the gingiva much like teeth, and a casting is created to fit over the posts. In preparation for a mandibular denture, a bar to provide stability connects these castings; this forms the "male" portion of the appliance. The denture is prepared with a recessed sleeve, which serves as the receptor attachment, in the anterior of the prosthesis; this is the "female" portion of the appliance. The denture is snapped over the bar and is stabilized in alignment with the opposing arch. The in-office steps required for the fabrication of this special denture are like those for a full denture

16. When is an immediate denture used?

An immediate denture is placed after an extraction of anterior teeth to serve as a compress and bandage to protect the surgical area.

17. What is the normal length of time an immediate denture is worn?

An immediate denture is usually worn for three to six months.

Procedure 52.4 Repairing a Fractured Denture (Expanded Function)

Consider the following with this procedure: Confirm with state guidelines before performing this procedure. Personal protective equipment (PPE) is required for the health care team, and the procedure is to be documented in the patient record. Equipment and Supplies • Fractured dentures • Sticky wax • Bunsen burner • Plaster to pour a cast • Low-speed handpiece • Acrylic burs • Auto-cured or light-cured acrylic Procedural Steps 1. Disinfect the denture. 2. Align the fractured denture parts and apply sticky wax over the fracture line on the external surface of the denture. 3. Examine the denture and block out all undercuts on the internal surface that will be exposed to the plaster with a slurry mix or blockout wax.PURPOSE Blocking out the undercuts enables you to remove the plaster cast after it sets.NOTE Do not block out undercuts along the fracture line. 4. Prepare a plaster mix. 5. Slowly pour the plaster into the internal surface of the denture. The plaster should cover the fracture line, but not the entire denture.NOTE This is accomplished by holding the denture in your hand and gently resting it against the vibrator. 6. Place the denture in an upright position and allow the plaster to set. 7. Once the plaster is set, gently remove it from the cast. 8. Remove the sticky wax and pumice. 9. With an acrylic bur, widen the fracture lines on the denture and place retentive grooves along the fracture line. 10. Apply a thin coat of the acrylic monomer to the fracture lines, then place a small amount of the acrylic powder, alternating the liquid and powder until the fracture line is filled. 11. Once the material has cured, the area is smoothed and polished on the dental lathe. 12. The denture is cleaned and disinfected and tried in for fit. 13. Document the procedure. DateToothSurfaceCharting Notes8/28/20Patient maxillary denture fractured at midline. Repaired with acrylic resin. Disinfected and polished. Pt pleased with fit and appearance.T. Clark, CDA/L. Stewart, DDS

Procedure 52.1 Assisting in the Delivery of a Partial Denture

Consider the following with this procedure: Personal protective equipment (PPE) is required for the healthcare team, and the procedure is to be documented in the patient record. Equipment and Supplies • Basic setup • Articulating paper and holder • Pressure indicator paste • Low-speed and high-speed handpieces • Pressure-indicator paste • Acrylic burs • Finishing burs • Three-pronged pliers Procedural Steps 1. Remove partial from laboratory packaging; disinfect and rinse to prepare for try-in. 2. Seat the patient. 3. The dentist places the new partial denture in the patient's mouth. 4. The patient is instructed to close his or her teeth together. 5. To check the occlusion, assist in placing articulating paper on the occlusal surface of the mandibular teeth, and ask the patient to simulate chewing motions. If the occlusion is too high, transfer handpiece with round carbide bur. 6. To detect pressure points (high spots) that could cause discomfort to the patient, apply pressure-indicator paste on the tissue surface of the prosthesis. The prosthesis is placed in the patient's mouth. As necessary, these high spots on the prosthesis are adjusted. 7. Retainers are examined for tension on the natural abutment teeth. Transfer pliers to the dentist to adjust the tension on the retainers. 8. After adjustments have been made, the partial denture is polished on the laboratory lathe with the appropriate pastes and sterile buffing wheels. 9. Scrub the partial denture with soap, water, and a brush; disinfect and rinse; and return the partial denture to the treatment room for delivery to the patient. 10 Instruct the patient on placement, removal, and care of the partial denture. 11. Document the procedure. DateToothSurfaceCharting Notes8/20/20—Delivered maxillary partial, minor adjustments made. Pt pleased with appearance and fit. Reschedule pt in 3 days for postdelivery check.T. Clark, CDA/L. Stewart, DDS

2. How does a person's occupation affect the choice of a removable prosthesis?

If a patient's occupation involves meeting the public, there may be concerns about the possible change in appearance during or after the transition to dentures.

13. What technique does the dentist use to modify the borders of an impression?

The dentist uses border molding to modify the borders of an impression.

3. How will the addition of a prosthesis affect the flow of saliva?

The presence of a new prosthesis increases salivary flow.

8. What component of a partial denture controls the way it is seated in the mouth?

The rest controls how a partial denture is seated in the mouth.

14. What is a smile line?

The smile line represents the amount of teeth that show when smiling.

11. What is the suction seal created between the denture and the mouth?

The suction seal between the denture and mouth is the post dam.

6. What is the term for the metal skeleton on a partial denture?

The term for the metal skeleton on a partial denture is the framework.

7. What is the term for the retainer on a partial denture?

The term for the retainer on a partial denture is the clasp.

Factors Influencing the Choice of a Removable Prosthesis

There are clinical and financial situations in which a removable prosthesis is the prescribed treatment of choice by the dentist. This is especially true when a patient does not want to undergo the surgery necessary for implant placement. The dentist will advise patients who are considering a removable prosthesis that it will never replace their natural dentition, regardless of how well it is constructed and fits. The dentist will assess the following factors before recommending this treatment plan for a patient. Extraoral Factors Although extraoral factors are usually beyond the control of the dentist, they should not be ignored when discussing this option with a patient. These factors include the patient's physical and mental health, motivation, age, occupation, and dietary habits, as well as social and economic factors. Physical Health Certain chronic medical conditions, such as diabetes, along with the types of medications taken, can affect how oral tissues tolerate the pressure of a removable prosthesis. Also, the patient who has poor health may be unable to manage the long procedures required. Mental Health Individuals with poor mental health may become agitated or concerned about having a denture in their mouth. Patients with severe mental disability or mental decline may not be able to keep the appliance in place or maintain adequate oral hygiene. Patient Motivation Occasionally, patients' major motive for having their teeth extracted and replaced with a prosthesis is for esthetic reasons, that is, only to improve their appearance. The dentist should explore all acceptable alternative treatment options before giving serious consideration to the request. Age A prosthesis for a young person must be designed to allow for growth and accommodate for new teeth as they erupt. If the patient is very active or plays contact sports, the strength of the appliance is also an important factor. A different challenge is found in the attitude of an older patient who associates the loss of teeth with aging and has an unrealistic desire to retain teeth that are structurally unsound. Dietary Habits Healthy oral tissue is an important aspect of removable prosthodontic success. Patients with poor nutritional habits may have poor tissue response to the prosthesis, which can affect the overall tolerance for and comfort of the prosthesis. Social and Economic Factors How important is it to the patient to replace lost teeth? Patients' attitudes about their oral health and appearance will help them decide whether dentures are important. The ability to pay for the treatment is a major economic factor. There are "denture clinics" or "mail order clinics," which cater specifically to the lower economic population by providing a quick, low-cost method in obtaining a denture. Occupation Patients whose daily activities involve "meeting the public" are concerned about the possible change in their appearance during or after the transition to partial or full dentures. Appointments for surgery and the delivery of the prosthesis should be scheduled without disruption to the patient's social and occupational activities. Intraoral Factors The condition of the tissues in the patient's mouth is a key factor in determining whether a removable partial or a complete denture should be recommended. Musculature Facial muscles contribute to retention and functional control of the prosthesis. Strong muscle attachments with good muscle tone are important. On the contrary, a large or very active tongue may cause difficulty in retention and wearing of the prosthesis. A patient with a nervous or physical facial habit may have difficulty retaining and adjusting to a prosthesis. Salivary Flow The presence of something foreign, such as a prosthesis, in the oral cavity can stimulate an excessive flow of saliva. This response usually diminishes as the patient becomes accustomed to wearing the prosthesis. However, if your patient has experienced a stroke or another type of neurologic disorder and there is paralysis, the prosthesis may make saliva control more difficult. In contrast, a patient with a lack of saliva may find it very difficult to wear a prosthesis and may be very uncomfortable. Physical conditions, medications, or radiation treatment may be the cause of inadequate salivary flow. Residual Alveolar Ridge Successful wearing of a removable prosthesis depends on the support provided by the alveolar ridge. If it is at normal height and is evenly contoured, the alveolar ridge should provide good support, allowing for an even distribution for the stress of mastication. If the alveolar ridge has resorbed anywhere within the ridge, this can result in a sore spot for the patient. Resorption occurs when the alveolar ridge has resorbed because of loss of teeth, causing an uneven distribution of pressure on the prosthesis, which keeps it from fitting properly. In some cases, it is necessary for the surgeon to perform an alveoplasty to recontour the alveolar ridge surgically to minimize such problems (see Chapter 56). It is a normal ongoing process for the alveolar ridge to continue to decrease in size and shape after teeth are lost. A well-fitted prosthesis minimizes these changes; a poorly fitting prosthesis accelerates the process. Because of these changes, it is important that the patient return periodically for an oral examination and for reevaluation in the fit of the prosthesis. Oral Mucosa When the mucosa that covers the residual ridge is altered by the patient's physical condition, the prosthesis may cause friction and irritation and be difficult for the patient to wear. Likewise, a poorly fitting prosthesis may cause irritation and sore spots, known as pressure points, on the oral mucosa. Patients should be seen promptly so the dentist can relieve these sore spots. Oral Habits Oral habits such as clenching or grinding can cause extreme stress on the ridges and remaining teeth, which must be considered when selecting a removable prosthesis. Mouth breathing may affect the patient's ability to hold the appliance in place. Tori Tori is a benign overgrowth of bone in a specific area. Mandibular or maxillary tori, when present, can affect the patient's ability to wear a prosthesis in that arch (see Chapter 17). Depending on the type of prosthesis, it may be necessary to have the tori surgically removed before fabrication of the appliance is begun.

resorption (ree-SORP-shun)

body's processes of eliminating existing bone or hard tissue structure

mastication (mas-ti-KAY-shun)

chewing

template (TEM-plut)

clear plastic tray to represent the alveolus as it should appear after teeth have been extracted

retainer (ree-TAY-nur)

device used to hold attachments and abutments of a removable prosthesis in place

5. What oral habits can affect the choice of a removable prosthesis?

Oral habits that affect prosthesis choice include clenching, grinding, and mouth breathing.

Denture Adjustment and Relining

Patients will assume that after they have received their denture, they are free from future dental visits. A patient should be scheduled yearly to evaluate the fit and to examine the oral tissues for subclinical irritation and dysplasia. If a denture places too much pressure on a specific area in the mouth, the area will eventually become sore. A patient's input is helpful in identifying the general location of sore spots, but sometimes patients cannot precisely pinpoint the location of irritations. Pressure-indicator paste is used for diagnosing problems with partials and dentures at insertion and adjustment appointments. Pressure-indicator paste is a layer of white silicone paste placed over the entire tissue surface of the denture and seated back in the patient's mouth and allowed to set for approximately 2 minutes. The denture is removed from the patient's mouth, and the areas on the tissue surface of the denture where the paste has been displaced by heavy contact from the tissue will indicate a high area, causing it to rub (Fig. 52.12). That will require adjustment using an acrylic bur outside the patient's mouth. FIG. 52.12 Example of denture with pressure-indicator paste showing a sore spot. (From Carr AB, Brown DT: McCracken's removable partial prosthodontics, ed 13, St Louis, 2016, Elsevier.) The clinical indications for relining or rebasing are as follows: • Dentures are loose or ill fitting. • A loss in vertical dimension occurs (angular cheilosis is an indication of this). • Inflammatory hyperplasia is present. • Traumatic ulcers appear after a long period of comfortable wear. Relining is accomplished by placing a new layer of denture resin over the tissue surface of the appliance. Rebasing is a similar procedure that replaces the entire denture base material on an existing prosthesis without changing the occlusal relationship of the teeth. The difference is that a reline resurfaces the prosthesis and a rebase replaces the denture base. Tissue Conditioners The process of relining a denture must be done accurately to ensure a proper fit. The patient's supporting tissue must be healthy before impressions can be taken. One method used to rehabilitate unhealthy supporting tissues is to place a tissue-conditioning material for a short period, usually 3 or 4 days. This material is a soft elastomer that is composed of a powder and a liquid. The mixed material is placed in the prosthesis and adapts to the supporting tissues and ridge, thereby providing a conditioning effect on unhealthy tissues. Impression At the preliminary appointment, the patient is informed that the denture will be unavailable for at least 8 to 24 hours while it is being processed in the laboratory. The impression is taken with the present (loose) denture used as the impression tray. The dentist flows a mix of zinc oxide-eugenol impression paste or an elastomeric impression material into the tissue side of the denture. The denture is placed on the alveolar ridge, and the patient is instructed to close in normal occlusion and hold the denture in place until the impression paste reaches a final set. The denture is removed from the mouth and disinfected. The denture and a written prescription are sent to the laboratory technician for relining. Delivery When the relined denture is returned from the laboratory, it is disinfected and sealed in a precautionary bag. After removing the denture, make sure to rinse in cool water before returning it to the patient. The relined denture rarely needs adjustment because the only alteration to the original prosthesis is the addition of material within the tissue side of the denture. If necessary, minor adjustments are made using an acrylic bur in a straight handpiece. Minor polishing may be done on the laboratory lathe with a sterile rag wheel with pumice paste; however, the tissue-bearing surfaces are never polished because this would alter the fit of the appliance. The patient is dismissed and is advised to return within a period specified by the dentist for a checkup of the tissue and of the adaptation of the prosthesis.

4. Why is it important that the alveolar ridge be evenly contoured for a removable prosthesis?

The alveolar ridge must be evenly contoured to fit properly and support mastication.

18. How is an overdenture supported in the mouth?

The bony ridge, oral mucosa, natural teeth, and implants support an overdenture in the mouth.

12. How many teeth are included in a full set of dentures?

A full set of dentures has 28 teeth.

1.What type of removable prosthesis replaces one or more teeth?

A partial denture is a removable prosthesis that replaces one or more teeth.

Denture Repairs

A patient may call the office upset because his or her denture or partial has fractured or has a missing or loose tooth (Fig. 52.13). The need for these repairs may be caused by changes in the oral tissues that place additional pressure on a certain area of the prosthesis or just by careless handling. A broken acrylic denture can be repaired. Simple repairs are commonly handled in the dental office laboratory with the use of auto-cured or light-cured acrylics. More complicated repairs, particularly those involving replacement of teeth or a fracture in the framework, are sent to the dental laboratory technician for repair. FIG. 52.13 Broken denture. In most cases, the patient would be instructed to come to the office so the denture can be repaired. See Procedure 52.4: Repairing a Fractured Denture.

Removable Partial Denture

A removable partial is a denture that replaces the missing teeth in a quadrant or arch. The partial receives its support and retention from the underlying tissues and remaining teeth that serve as abutments. This type of prosthesis is designed to distribute the forces of mastication between the abutments and the supporting tissues. Considerations for Prescribing a Removable Partial Denture Indications for a Removable Partial Denture • To replace several teeth in the same quadrant or in both quadrants of the same arch • To serve as a temporary replacement for missing teeth in a child (as necessary, a new appliance is constructed to compensate for the child's growth) • To avoid additional reduction in tooth structure on primary or permanent dentition of children and adolescents • To replace missing teeth for a patient who cannot tolerate longer appointments and the extensive preparation required for placement of a fixed bridge or implants • To allow the patient to maintain good oral hygiene • To serve as a splint to support periodontally involved teeth Contraindications to a Removable Partial Denture • A lack of suitable teeth in the arch to support, stabilize, and retain the removable prosthesis • Rampant caries or severe periodontal conditions that threaten the remaining teeth in the arch • Lack of patient acceptance for esthetic reasons • Chronic poor oral hygiene Components of a Partial Denture The basic components of a removable partial denture are the framework, connectors, denture base, retainers, rests, and artificial teeth (Fig. 52.3). FIG. 52.3 Framework for mandibular removable partial denture with the following components: 1, lingual bar major connector; 2a, minor connector to which the resin denture base will be attached; 2b, minor connector, proximal plate, which is part of clasp assembly; 2c, minor connector used to connect rests to major connectors; 3, occlusal rests; 4, direct retainer arm, which is part of the total clasp assembly; 5, stabilizing or reciprocal components of clasp assembly (includes minor connectors); and 6, an indirect retainer consisting of a minor connector and an occlusal rest. (From Carr AB, Brown DT: McCracken's removable partial prosthodontics, ed 13, St Louis, 2016, Mosby.) Framework The framework is the cast metal skeleton that provides support for the remaining components of the prosthesis. The dental laboratory technician constructs this meshlike portion of the partial denture and then covers the framework with acrylic resin to mirror the appearance of gingiva. Connectors The connectors, or bars, join the various parts of the partial denture. The major connector is the piece of rigid metal that joins the right- and left-quadrant framework of the partial denture. This connector also helps provide support for the remaining teeth, so the stress is evenly distributed. A maxillary partial denture will have a palatal connector, and the mandibular partial denture will have a lingual connector. A stress breaker is a metal device built into a partial denture design to protect the abutment teeth from excessive occlusal weight and stress during mastication. A stress breaker is advised for abutment teeth that have limited support in the alveolar ridge. The minor connector links the major connector to the base and other areas, such as rests and clasps. Retainer A retainer, also known as a clasp, is the portion of the framework that directly supports and provides stability to the partial denture by partially encircling or resting on an abutment tooth. The I-bar retainer, or I-bar clasp, approaches the tooth in a straight line from the apical direction and extends upward against the tooth (Fig. 52.4, A). A circumferential retainer, or C-clasp, originates at the occlusal surface of the tooth and extends downward, so that it partially encircles the tooth (see Fig. 52.4, B). FIG. 52.4 Different types of clasps. (A) I-bar clasp. (B) C-clasp. Rest A rest is a metal projection designed to control the seating of a prosthesis as it is positioned in the mouth. Rests prevent the partial denture from moving in a gingival direction, which can place abnormal stress and wear on the abutment tooth. The rest also aids in distributing the retention load of the partial denture to several teeth, not just to a single tooth. It also prevents passage of food between the abutment tooth and the retainer. Rests are designed to lay within a prepared recess on the occlusal or lingual surface of a tooth. If a cast restoration is in place on the abutment tooth, the rest is positioned to protect the tooth structure against wear. Although the rest fits into the casting, it is not attached to it. Two common types of rests are the following: • The occlusal rest, which is on the occlusal surface of the tooth. This placement minimizes trauma to the tooth by transmitting stress along the long axis of the tooth. • The lingual rest is placed on the cingulum of the lingual surface of the tooth, where support is good, but away from visibility. Artificial Teeth Artificial teeth are constructed from acrylic resin or porcelain (Fig. 52.5). Acrylic resin teeth are lighter in weight, can be modified, and produce less noise, although there is a clicking sound during chewing; however, acrylic teeth tend to wear faster and are more susceptible to staining. Porcelain teeth are more susceptible to fracture and tend to cause abrasion of the opposing natural teeth. Placement of acrylic teeth with natural or porcelain teeth in the opposing arch often is a good compromise. FIG. 52.5 Artificial teeth. (Courtesy Ivoclar Vivadent Inc., Amherst, NY.) Appointment Sequencing for a Partial Denture The patient who is considering a partial denture should be educated about the sequencing of and commitment to the process of delivering a partial denture. A patient can expect multiple dental appointments before the prosthesis is delivered. Appointment One: Records This appointment involves the preliminary steps taken to gather the diagnostic tools that the dental team and laboratory technician will need to proceed: • Updated health and dental history. • Prophylaxis completed by the dental hygienist. • Preliminary impressions and casts completed by the expanded-functions dental assistant (EFDA)/registered dental assistant (RDA) and in stone, for the fabrication of the custom trays either within the office or when sent to the dental laboratory. • Periapical radiographs are prescribed for the evaluation of decay, periodontal problems, and other disease that cannot be seen visually. A panoramic (Panorex) radiograph may be prescribed to evaluate the alveolar ridge and any additional structures. • Photographs are important to have intraoral and extraoral photographs for the case presentation and for presentation of final seating. Appointment Two: Preparation The second appointment is the preparation appointment. • Selecting the shade and mold of the teeth. When choosing the tooth shade and mold, the dentist considers the patient's age, body size, length of the lip, and space to be occupied by the artificial tooth or teeth. The goal is to match as closely as possible the color, size, and shape of the patient's natural teeth. When the selection has been made, the mold and shade of the artificial teeth are entered in the patient's record. • Preparation of the teeth. The type of rest selected determines the preparation of the abutment teeth. This preparation may involve one of the following:• Slight modification of the tooth structure• Modification of amalgam restorations, if present• Placement of a cast metal restoration with a recessed area to receive the rest or precision attachment • Taking the final impression. Because this must be an exact impression, an elastomeric material is used. A custom tray may have been prepared for taking the final impression to give the laboratory technician a better form for the surrounding structures. • Taking the bite and occlusal registration. Jaw registration must be recorded to determine the relationship between the maxillary and mandibular arches. • Preparing the laboratory prescription. Before the case is sent to the laboratory, the dentist prepares a written prescription that includes all details regarding construction of the prosthesis (Fig. 52.6). A copy is retained in the patient's record.FIG. 52.6 Laboratory prescription. (Courtesy DDS Lab, Tampa, FL.) Appointment Three: Try-in An appointment is scheduled for the initial try-in of the prosthesis. At this point, the appliance consists of the cast framework and the artificial teeth set in wax. The dentist evaluates the fit, comfort, and function of the appliance. The shade, mold, and arrangement of the teeth are reviewed to ensure that the appearance is acceptable to the patient. If necessary, the dentist may alter the alignment of the teeth in the wax. When the appliance is acceptable, another bite registration may be required to reflect any changes made during the try-in. Any changes in partial denture design are noted on the laboratory prescription. The wax-up is disinfected and is returned to the dental laboratory along with the prescription. Appointment Four: Delivery A 20- to 30-minute appointment is usually adequate for delivery of the partial denture. On the day before the appointment, verify that the case has been returned from the laboratory. (See Procedure 52.1: Assisting in the Delivery of a Partial Denture.) Appointment Five: Postdelivery Check The patient is scheduled for an appointment to return within a few days after delivery of the partial denture. A 10- to 20-minute appointment is adequate for this postdelivery visit. The dentist will remove the partial denture and check the mucosa for pressure areas and sore spots. If necessary, minor adjustments are made. When the dentist and the patient are satisfied that the prosthesis is functioning correctly, the patient is given a recall appointment for several months later. It is important that the patient return for the recall visits so the dentist can evaluate the fit, changes in mucosa, function of the prosthesis, and effectiveness of the patient's oral hygiene. As time passes, changes in the alveolar ridge and surrounding tissues may make it necessary to reline the partial denture (see later in the chapter for discussion). Home Care Instructions Patients with a removable partial are instructed to maintain good oral hygiene; the importance of this cannot be overemphasized. Patients should be provided home care instructions verbally in the office and written instructions that can be used at home to reinforce education after the patient has left the office. • When not wearing it, store the prosthesis in water or in a moist, airtight container. • After eating, remove the partial denture from the mouth, and brush or rinse the retainers, rests, and complete partial prosthesis. • Carefully brush and floss the abutment teeth and the remaining natural teeth to keep them free of food debris and plaque. • Do not adjust the partial denture. The patient should contact the dentist if he or she has any difficulties.

Procedure 52.3 Assisting in the Delivery of a Full Denture

Consider the following with this procedure: Personal protective equipment (PPE) is required for the healthcare team, and the procedure is to be documented in the patient record. Equipment and Supplies • Basic setup • Dentures • Hand mirror • Articulating paper and holder • High-speed and low-speed handpieces • Pressure-indicator paste • Finishing burs • Acrylic burs Procedural Steps 1. Remove denture from laboratory packaging; disinfect and rinse to prepare for try-in. 2. Seat the patient. 3. Assist the patient in inserting the new denture into the patient's mouth. 4. Hand the patient a mirror and evaluate the shade and mold of the artificial teeth for natural appearance. 5. Ask the patient to perform facial expressions and the actions of swallowing, chewing, and speaking, using s and th sounds.NOTE These sounds also are appropriate for exercises to help the patient learn to speak normally with the new denture. 6. Assist in checking the occlusion, by placing articulating paper on the occlusal surface of the mandibular teeth and ask the patient to simulate chewing motions.PURPOSE Cusps that are too high in contact will be marked with the color of the articulating paper. 7. If the cusps are too high, the denture is removed from the mouth and is adjusted with a stone mounted on a straight handpiece. 8. The denture is replaced in the mouth, and the procedure is repeated until the cusps appear to be in occlusion with the opposing arch.NOTE If the denture must be taken into the laboratory for adjustment, it must be disinfected again before it is returned to the patient. 9. When the patient is pleased with the appearance, function, and comfort of the denture, another appointment is made for the postdelivery checkup. 10. After adjustments have been made, the partial denture is polished on the laboratory lathe with the appropriate pastes and sterile buffing wheels. 11. Scrub the denture with soap, water, and a brush; disinfect and rinse; return the denture to the treatment room for delivery to the patient. 12. Instruct the patient on placement, removal, and care of the denture. 13. Before dismissal, the patient is informed that learning to wear a new denture will take several days or weeks. 14. Document the procedure. DateToothSurfaceCharting Notes8/28/20Delivery of maxillary full denture. Pt pleased with change of canines. Teeth and shading good. Pt pleased with fit and appearance. Reschedule in 3 days for postdelivery check.T. Clark, CDA/L. Stewart, DDS

Procedure 52.2 Assisting in a Wax Denture Try-in

Consider the following with this procedure: Personal protective equipment (PPE) is required for the healthcare team, and the procedure is to be documented in the patient record. Equipment and Supplies • Denture wax setup • Basic setup • Articulating paper and holder • Wax spatula • Heat source • Low-speed handpiece with acrylic burs, discs, and stones Procedural Steps 1. Remove wax setup from laboratory packaging; disinfect and rinse to prepare for try-in. 2. Seat the patient. 3. Assist in placing the wax setup of the denture for fit, comfort, and stability. 4. Assist with verifying the appearance of the denture teeth, which will include the shade selection, the size of the teeth, and alignment of the teeth. 5. Assist with the evaluation of the retention of the denture by asking the patient to articulate specific letters; f, v, s, and th sounds; swallows; and yawns. 6. Assist in checking the occlusion by placing articulating paper on the occlusal surface of the mandibular teeth, and ask the patient to simulate chewing motions. If the occlusion is too high, transfer handpiece with round carbide bur. 7. Prepare the laboratory prescription for completion of the denture. 8. Disinfect the case, return it to the articulator, pack it, and return the case to the laboratory. 9. Document the procedure. DateToothSurfaceCharting Notes8/20/20—Wax try-in of maxillary denture, base contoured and adjusted. Pt unhappy with canines. Noted on laboratory script for change in mold of#s 6 and 11. Centric occlusion evaluated and adjusted. Pt rescheduled for delivery in 1 week.T. Clark, CDA/L. Stewart, DDS

10. In what are the artificial teeth set during the try-in appointment?

During the try-in appointment, the teeth are set in wax.

9. What impression material is typically used when one is taking a final impression for a partial denture?

Elastomeric impression material is typically used when one is taking a final impression for a partial denture.

Full (Complete) Denture

Full dentures are designed to restore the function and esthetics of the natural dentition when all the natural teeth are missing. A complete denture receives all its support and retention from the underlying tissues, alveolar ridges, hard and soft palate, and surrounding oral mucosa. Considerations for Prescribing a Full Denture Major Indications for a Full Denture Include the Following: • The patient is totally edentulous. • The remaining teeth cannot be saved. • The remaining teeth cannot support a removable partial denture, and no acceptable alternatives are available. • The patient refuses alternative treatment recommendations. Contraindications to a Full Denture Include the Following: • Another acceptable alternative is available. • Physical or mental illness affects the patient's ability to cooperate during fabrication of the denture and to accept or wear the denture. • The patient is hypersensitive to the denture materials (a hypoallergenic denture material may be indicated). • The patient is not interested in replacing missing teeth. Components of a Full Denture The basic components of a denture include the base, flange, post dam, and artificial teeth (Fig. 52.7). FIG. 52.7 Full denture showing the base, flange, and artificial teeth. (Copyright iStock.com/contrail1.) Base The base is designed to fit over the residual alveolar ridge and surrounding gingival area. The base is commonly made from denture acrylic. To provide additional strength, however, it may be reinforced with a metal mesh embedded in the acrylic. Flange The flange is the part of the base that extends over the attached mucosa from the cervical margin of the teeth to the border of the denture. The flange of the mandibular denture base extends over the residual ridge and attached mucosa, down to the oblique ridge and mylohyoid ridge, and over the genial tubercles and retromolar pads. The flange of the maxillary denture base extends beyond the residual ridge and over the attached mucosa to the tuberosities and the junction of the hard and soft palates. Post Dam Retention of a maxillary denture depends on the suction seal known as the post dam, or the posterior palatal seal. The base of a maxillary denture covers the entire hard palate, and the seal is formed at the junction of the tissues and the posterior border of the denture. The post dam extends across the entire posterior portion of the denture from one buccal space across the back of the palate behind the maxillary tuberosity (rounded area on the outer surface of the maxillary bones) to the opposite buccal space. Retention for a mandibular denture depends on the support of the remaining alveolar ridge and the suction achieved between the prosthesis and the tissues covering the ridge. Achieving good retention of a mandibular denture can be difficult. A mandibular denture lacks the broad suction area found in a maxillary denture, and the constant action of the tongue can dislodge it. For these reasons, retained teeth or implants are desirable to help hold the appliance in place. Artificial Teeth Denture teeth are fabricated from acrylic resin or porcelain and are designed to be retained in the acrylic base of the denture. Third molars are not included in dentures because space is needed in the posterior region to allow the patient to close, chew, swallow, and speak normally. A full denture will have 14 teeth per arch; each arch acts as a single unit, whereas a natural tooth functions as an individual unit. Appointment Sequencing for a Full Denture The patient who is considering a complete denture must be educated about the sequencing and commitment to the process of delivering a denture. It is common for a patient to have six dental appointments for delivery of a denture. Appointment One: Records The first appointment involves the preliminary steps involved in gathering the diagnostic tools that the dental team and dental laboratory technician will require to proceed with the removable prosthodontic procedure: • Updated health and dental history. • Preliminary impressions. An alginate impression of an edentulous arch differs from other alginate impressions in two ways: (1) The height of the teeth is missing, and (2) more extensive tissue details are needed. An edentulous tray will be used to take this impression. This tray is not as deep, but if the tray requires modification to accommodate space and depth in the mucobuccal fold, a rope wax may be added to the borders of the tray. • Tray modification allows border molding, also known as muscle trimming, to achieve closer adaptation of the edges of the impression to the tissues in the mucobuccal fold. Border molding is performed after the impression tray is in place. The dentist will use his or her fingers to gently massage the facial area over these borders. This action shapes the tray's wax-covered edges so that they more closely resemble the tissues. • Radiographs. A panoramic radiograph may be prescribed for the dentist to evaluate the underlying bone structure and observe any disease that may not be visible. • Photographs. It is important to have intraoral and extraoral photographs for the case presentation and final results. Appointment Two: Final Impression The dental laboratory technician requires a final impression to create the base of a denture. Before the impression is taken, a custom tray is fabricated. Because of the shape of the edentulous arch, custom trays are required for the final impression. Custom trays are constructed from the diagnostic casts and are prepared before the patient's appointment for the final impression (see Chapter 47). The edges of the custom tray for an edentulous arch are modified with beading wax to allow border molding. The edges of the tray should extend to 2 mm short of the mucobuccal fold. Because accuracy is essential, an elastomeric impression material is selected for the final impression for creation of the baseplates and occlusal rims (Fig. 52.8). FIG. 52.8 Final impression for a full denture. (Courtesy Ivoclar Vivadent, Inc., Amherst, NY.) Essentials of a Final Impression for Dentures • The impression material should be free of bubbles and distributed evenly over the tray and its margins, so that landmarks of the dental arches are accurately reproduced. • The maxillary impression should include the hamular notches, post dam, tuberosities, and frenum attachments. • The mandibular impression should include the retromolar pads; oblique ridge; outline of the mylohyoid ridge; genial tubercles; and lingual, labial, and buccal frenula. The baseplate, which is constructed on the master casts, is made of a semirigid material such as shellac and self-curing or heat-cured resins. If necessary, for added stability, acrylic baseplates may be reinforced with wires or mesh metal sheets embedded in the material at processing. The occlusal rims are built of wax on the alveolar crest of the baseplate and are sufficiently high and wide to occupy the space of the missing dentition. Appointment Three: Try-in of Baseplate and Occlusal Rim The baseplate-occlusal rim assembly is returned to the dental office on an articulator, a dental laboratory device that simulates movement of the mandible and the temporomandibular joint. Before it is tried in the patient's mouth, the baseplate-occlusal rim is removed from the articulator, disinfected, and rinsed. On the occlusal rims, the dentist records the following: • Vertical dimension: space occupied by the height of the teeth in normal occlusion • Occlusal relationship: centric, protrusive, retrusive, and lateral excursions • Smile line: line representing the area of the teeth that is visible when the patient is smiling • Canine eminence: vertical line that indicates the locations of the canines Artificial Teeth At this appointment, the mold, shade, and material of the artificial teeth to be placed in the denture are selected (Fig. 52.9). These factors are determined in the same way as for the teeth of a partial denture. FIG. 52.9 Lab technician placing teeth in the wax baseplate occlusal rim. (Copyright iStock.com/izusek.) When placing the teeth in the denture, the laboratory technician can modify the arrangement as requested to produce a more natural appearance for the patient, for example, by lightly overlapping the mesial incisal margin of the maxillary lateral incisor over the distal margin of the central incisor. In addition, the technician may set (position) the teeth to expose less or more of the cervical area of the teeth to emulate their natural setting according to the patient's age. Less cervical area is shown in a younger patient; more area is visible in an older patient to simulate gingival recession. Occlusal Registration During construction of a complete denture, the laboratory technician must have an accurate and extensive record of the patient's occlusion. The technician uses this information to articulate the casts so the completed prosthesis will replicate these normal motions. The measurements most frequently used are the patient's bite registered in the following positions: • Centric relation, with the jaws closed, relaxed, and comfortably positioned • Protrusion, with the mandible placed as far forward as possible from the centric position • Retrusion, with the mandible placed as far posterior as possible from the centric position • Lateral excursion, which involves sliding the mandible to the left or right of the centric position These exaggerated motions simulate the actual movements of the mandible as it functions during the acts of mastication, biting, yawning, and speaking. Various measuring devices are used to obtain these measurements. Functionally Generated Path Technique The functionally generated path technique uses the patient's ability to create his or her own occlusal relationship by tracing in wax the movements of the mandible on the maxilla. Establishment of a functionally generated path involves the following steps: 1. Place the baseplates and occlusal rims for the new prosthesis in the patient's mouth. 2. Prepare a double thickness of specially formulated baseplate wax in a horseshoe shape and lay it over the occlusal surface of the mandibular teeth. 3. Instruct the patient to close firmly into the wax and simulate the act of chewing as accurately as possible. 4. Remove the wax bite after approximately 20 to 30 seconds. 5. In the treatment room, rinse and disinfect the wax bite and place in a precaution bag. 6. In the laboratory, pour the wax bite in stone immediately after the patient's dismissal. Appointment Four: Try-in The wax setup consists of the baseplate with the artificial teeth set in wax that resembles gingival tissue. The shaping of the wax to simulate normal tissue contours, grooves, and eminences is known as festooning. The teeth are articulated according to the bite registration of the patient's occlusion, as established on the articulator through a functional arch tracing. The complete denture try-in, which has been fabricated in wax by the laboratory technician on an articulator, is returned to the dental office before the patient's appointment. The wax setup is removed from the articulator and is disinfected before it is tried in the patient's mouth (Fig. 52.10). FIG. 52.10 Wax setup within the articulated cast. See Procedure 52.2: Assisting in a Wax Denture Try-in. Patients may require more than one wax try-in appointment to achieve the esthetics they are seeking. It is important for the dentist, laboratory technician, and patient to work together to achieve the patient's acceptance and satisfaction. Appointment Five: Delivery The completed dentures are delivered to the dental office in a sealed, moist container. The dentures must be disinfected before they are placed in the patient's mouth. (See Procedure 52.3: Assisting in the Delivery of a Full Denture.) Appointment Six: Postdelivery The patient is scheduled to return 2 to 3 days after delivery of the full denture. A 10- to 20-minute appointment is usually adequate for this postdelivery visit. The dentist removes the denture and checks the mucosa for pressure areas and sore spots. If necessary, minor adjustments are made to the denture. Patients may need more than one adjustment appointment after the delivery of a complete denture. When the patient and the dentist are satisfied that the prosthesis is functioning properly, the patient is given a recall appointment for several months later. Home Care Instructions As with partial dentures, the patient should be given home care instructions in writing to reinforce the verbal instructions, as follows: • With the denture removed, thoroughly rinse the oral tissues at least once daily. • On removal, thoroughly clean all surfaces of the denture; a special denture brush may be used. Avoid harsh abrasives such as toothpaste (Fig. 52.11).FIG. 52.11 Instruct the patient to brush the denture under running water over the sink. (Copyright iStock.com/alexshor.) • During cleaning, carefully hold the denture over a sink half-filled with cool water. • Do not soak the denture in hot water or a strong solution such as undiluted bleach, because these liquids will damage the denture. • When not in the mouth, store dentures in a moist, airtight container to prevent drying and warping. If the prosthesis is not stored in a safe container, it may be accidentally knocked to the floor, stepped on, or broken. • Do not wear the denture at night. What to Expect the First Month Day 1—Your "adjusting to dentures" journey is just beginning; even for experienced denture wearers, new dentures can be a challenge. Many first-time denture wearers say that eating soft foods that are gentle on your gums/teeth makes this new experience easier. Days 2 to 14—Your mouth is adjusting to the new dentures; you will likely experience increased salivation. You might also experience sore spots in your mouth from the dentures. Rinsing your mouth with warm salt water may help. If soreness persists, return to your dentist for an adjustment. Expect a longer denture adjustment and healing time if you recently had teeth extracted or are a full-denture wearer. Days 15 to 29—You are still learning to talk and eat all over again. You also are adjusting to the foreign-object feeling in your mouth. The saliva flow and sore spots have lessened. This is the best time to start using an adhesive to improve the fit and feel of your dentures. Be careful to follow the usage directions and not to use too much! The more you wear your dentures, the more quickly you will adjust. Day 30—You've made it through 1 month with dentures! Reward yourself with your favorite food. Remember to visit your prosthodontist on a regular basis to have your dentures checked. It is usually recommended that you get new dentures in 5 to 10 years.

Denture Duplication

Having a functional denture is important to the patient, and because dentures can break or may require time for relining, the patient can opt to have a duplicate denture. Although it involves an extra expense, many patients find that a duplicate is an excellent investment because they will not be without their denture if the original is damaged. To prevent warping while not in use, the spare denture should be stored in a moist, airtight container.

15. What are the four jaw positions that the dentist measures when articulating a denture?

When articulating a denture, the dentist measures centric relation, protrusion, retrusion, and lateral excursion.

overdenture

full denture supported by one or more remaining natural teeth or implant

immediate denture

full or partial denture placed immediately after the extraction of teeth

centric (SEN-trik) relation

having the maxilla and mandible in a position that produces a centrally related occlusion

border molding

manipulation of the soft tissue and impression material of the border areas to duplicate a closer version of the contour and size of the vestibule

rest

metal projection on or near the retainer of a partial denture

framework

metal skeleton of a removable partial denture

connector

metals that join the various parts of a partial denture

flange (flanj)

portion of a full or partial denture that extends into the vestibule

protrusion (proe-TROO-zhun)

position of the mandible placed forward as related to the maxilla

retrusion (ree-TROO-zhun)

position of the mandible posterior from the centric position as related to the maxilla

post dam

posterior extension of a full denture to complete a seal with the soft palate and hold the denture in place; also called posterior palatal seal

rebasing (ree-BAY-sing)

procedure to replace the entire denture base material on an existing prosthesis

relining (ree-LYE-ning)

procedure to resurface the tissue side of a partial or full denture so that it fits more accurately

festooning (fes-TOO-ning)

process of placing wax on the denture base, then carving the base of a denture to reproduce natural contours and aid in retention

full denture (DEN-chur)

prosthesis that replaces all the teeth in one arch

partial denture

removable prosthesis that replaces teeth within the same arch

tuberosity (too-buh-ROS-i-tee)

rounded bony protrusion behind the last molar in the maxilla

lateral excursion (ek-SKUR-zhun)

sliding the mandible to the left or right of the centric position

pressure points

specific areas in the mouth where a removable prosthesis may rub or apply more pressure and cause pain

alveoplasty (al-VEE-uh-plas-tee)

surgical reshaping and smoothing of the ridges of the alveolar crest after extraction of a tooth or teeth to prepare the area for the placement of a denture

baseplate

temporary resin structure that represents the base of a denture, used to help establish jaw relationships and the arrangement of teeth

coping (KOEP-ing)

thin metal covering or cap placed over a prepared tooth

edentulous (ee-DEN-tyoo-lus)

to be without teeth

occlusal (o-KLOO-sul) rim

wax rim attached to the denture baseplate for the purpose of creating the relation of the mandibular and maxillary arches and arranging the teeth