Clinical Policy for Prosthodontic Procedures
TREATMENT PLANNING
Phased Treatment
With the exception of interim removable complete and partial dentures, all prosthodontic treatment is considered Phase II care, which is elective. This includes definitive complete denture, framework partial denture, crown and bridge, inlays and onlays, porcelain veneers, and cast post and core. No definitive prosthodontic treatment may be rendered without first establishing disease control. However, if the patient has unstable periodontal disease or moderate to high caries risk, Phase II options must be considered at the time that Phase I is planned, so that time and finances are not spent on teeth which ultimately may be eliminated from the Phase II plan after disease control has been established.
All treatment plans will require a "Phase I Re-evaluation" (procedure code # 0040) before Phase II treatment can begin. For this procedure, Caries Risk Assessment and Periodontal Re-evaluation must be conducted and updated on all patients, regardless of initial health status, to confirm that disease is controlled and the patient is ready to begin Phase II treatment. Appropriate radiographic updates may be required prior to the initiation of the Phase II plan. For example, if a tooth was restored during Phase I, which now requires a crown restoration, a new radiograph may be indicated.
Patients Presenting with Extensive Disease
On occasion, dental caries and/or periodontal disease may be so complex that the outcome of Phase I treatment is questionable and Phase II treatment is impossible to predict. If periodontal disease is the main problem, initial therapy may be required to determine the feasibility of saving teeth for Phase II care. If dental caries is the main problem and the patient wishes to save many teeth of questionable restorability, referral is required to the AEGD fellowship, Faculty Practice, or private sector. If the patient desires a simpler treatment plan which includes extractions and restoration of a reasonable number of teeth and is willing to wait in interim restorations for disease control, then the patient may be an acceptable candidate for the undergraduate student clinic. For this patient, a Pre-Phase I Treatment Plan may be needed.
Pre-Phase I Treatment Plan
If a patient with extensive disease is interested in a simplified treatment plan, such a patient may be treated in the undergraduate program. In this case, a pre-Phase I plan may be created which includes caries removal on several questionable teeth and may also require initial periodontal therapy and re-evaluation prior to developing the Phase I treatment plan. The patient is informed that no final Phase I plan can be made until restorability of all the teeth is determined and/or the response of the tissues to periodontal therapy has been determined.
When there are teeth with extensive dental caries such that an amalgam or composite restoration will not be ideal treatment, each questionable tooth must be evaluated for restorability by the prosthodontic consultant. The consult should be requested after complete caries removal and before temporization, At each restorability consultation the patient is given possible options for each tooth and all issues are documented in the record until all questionable teeth are restored. In the patient with moderate to high caries risk, restorable teeth will be temporized with amalgam or resin composite, since a sedative temporary will not last the year needed to establish disease control. If a tooth is non-restorable, it may be temporized with a sedative restoration.
Phase I Treatment Plan following the Pre-Phase I Treatment
When all questionable teeth with caries have been evaluated for restorability and/or teeth of questionable periodontal prognosis have been identified, prosthodontic consultation is required. The consultant will act as assistant to the supervising doctor in developing the Phase I plan, while considering all possible Phase II options which might occur if and when disease control is finally established. The Phase I plan will allow for all hopeless and non-restorable teeth to be extracted, definitive periodontal treatment to be rendered, additional operative dentistry to be completed, and interim partial or complete dentures placed, if needed.
Patients with moderate to high caries must wait for a minimum period of one year following caries removal, with bitewing radiographs and clinical evaluation a minimum of every 6 months (See the Caries Risk Assessment Form). If the patient shows no radiographic or clinical lesions and the etiologic factors for the caries are reasonably controlled after one year, the patient will be eligible to undergo Phase I re-evaluation (#0040) and move forward to Phase II treatment.
Phase I Only" Care
In selected cases it may be practical to offer Phase I care only, though the patient technically may be a candidate for Phase II care. Patients who have limited finances, problems with transportation, physical limitations, or simply do not desire tooth replacement may be best served by treatment for disease control only. Phase I only treatment plans must provide predictable outcomes that can stand alone without Phase II treatment. .
Informed Consent
The full range of options must be offered to all patients as part of "informed consent." For patients who may be candidates for complex fixed or removable partial dentures or for dental implants, discussion of these options must be presented to the patient whether or not such treatment can be rendered at the School of Dentistry.
If the patient expresses an interest in implant treatment, a consultation with the course director of the Implant Elective Program may be scheduled prior to finalizing the treatment plan. The course director will do the consultation in the undergraduate clinic with the student, patient, and faculty member requesting the consultation present at the appointment. The appointment may be arranged by calling the implant co-ordinator in the PCC Office.
Patient Dismissal
A patient may be dismissed during the diagnosis or treatment planning phase by the prosthodontic consultant and oral diagnosis/treatment manager/comprehensive care faculty. The Screening Appointment does not routinely utilize radiographs, and patients are told that they may be dismissed at any time prior to the development of an approved treatment plan. Dismissal may be due to a number of factors including, but not limited to, the following:
1. Presence of an existing unstable or ill-fitting prosthesis that the patient does not want replaced.
2. Inability to give informed consent.
3. Technical complexity beyond the scope of the student clinic. (See policies for each discipline
to follow)
4. Patient compliance issues.
5. Unstable joint disease or chronic head and neck pain.
6. Overclosed vertical dimension of occlusion in a dentate patient requiring correction.
7. Patient wishes to preserve many teeth with extensive caries/periodontal disease requiring
management beyond our student care and maintenance capabilities.
8. Patient desires a crown retrofitted to an existing RPD. (If the RPD was done at UDM clinic,
referral to the Group Practice Administrator for Risk Assessment
Evaluation.)
9. Patient desires an RPD using an incisor tooth as a primary abutment.
10. Patients with pre-existing dental implants.
Payment
Payment policy for prosthodontic care requires the patient pay 1/3 of the cost at the initiation of treatment, the second 1/3 before the case goes to the dental laboratory, and the final 1/3 at placement. See the Financial Services Department for eligibility regarding a customized payment program.
Students will not be awarded CPU credit for any prosthesis delivered without payment.
Consultations
All patients who are candidates for prosthodontic care require a formal consultation from the prosthodontic faculty member of the day (*This symbol identifies the consultant on the clinic schedule). Both the consultation request and response must be in writing in the patient record. Teamwork is expected in all clinics for continuity of patient care and student experience.
In the DS3 Clinic, discussion and coordination among treatment manager, oral diagnosis faculty, and prosthodontic faculty is essential. For straightforward treatment plans, discussion between the prosthodontist and treatment manager may be very brief, or it may require a separate meeting with consultant, treatment manager and student, if the situation is complex. This discussion must take place before the final treatment options are presented to the patient for informed consent.
In the DS4 clinic, oral diagnosis and treatment planning are supervised by a comprehensive care faculty member with consultation from the prosthodontist for all Phase I and II treatment plans.
Early Consultation
Occasionally a patient will present with circumstances, which will probably require full mouth extractions and complete denture treatment. In this case the treatment manager and oral diagnosis or comprehensive care faculty member will request that the prosthodontist see the patient before all the data collection is complete to confirm the need for extractions and complete dentures. This will help avoid unnecessary data collection. An early consultation is also indicated when the oral diagnosis faculty and/or treatment manager or comprehensive care faculty member has doubts about the suitability of the patient for the student clinic.
Preparation for the Consultation
Casts
Students must have neatly trimmed casts in dental stone made from irreversible hydrocolloid impressions with full vestibular extensions and hamular notch or retromolar pad present bilaterally.
- Dentate casts (4 sets of occlusal contacts distributed like 4 legs of a table) must be mounted on a semi-adjustable articulator with a facebow transfer in ICP. Hand articulation without a PVS interdental record works best for the maxillo-mandibular relationship when the teeth fit precisely together. You may wish to take a PVS registration for your reference, but using it to mount the casts usually reduces the accuracy of the mounting.
- Partially edentulous casts with missing molars require record bases with wax rims to mount the mandibular cast accurately. Facebow transfer must be used for the maxillary cast and the mandibular cast must be mounted in ICP.
- Mounted casts for completely edentulous patients or patients with edentulous maxillary arch opposing partially edentulous mandibular arch(combination case) are not needed routinely. However, the prosthodontic consultant may request mounted casts if the patient requires pre-prosthetic surgery. Record bases with wax rims are required and the correct VOD must be established with the wax rims prior to mounting in centric relation.
- On occasion, the student may be required to perform a diagnostic wax-up at the discretion of the faculty team of prosthodontist and comprehensive care or treatment manager faculty member.
Mounting partially edentulous casts is often difficult and nearly impossible if the patient has even a single mobile tooth. Treatment manager, restorative faculty or comprehensive care faculty, and prosthodontist may need to assist the student. Mounted casts are correct when they demonstrate the same relationships of tooth contacts and edentulous ridge relationships as exist in the patient at ICP
Other Materials Needed for Consultation
- Medical and dental history
- Patient chief complaint
- Radiographs
- Periodontal chart with odontogram
- Caries Risk Assessment
- Surveyor, if a removable partial denture may be an option
Treatment Plan
It is often necessary for the prosthodontist to talk with the patient and student more than once. The final Phase II treatment plan is a negotiation process that often requires time for the patient to process the information. Discussion with other specialists and the treatment manager or the comprehensive care faculty member may be needed to establish a final plan. The final Phase II treatment plan must be approved by the treatment manager or comprehensive care faculty member after informed consent has been given. A signed partial denture design form (blue) is required for approval of the treatment plan if a definitive RPD is planned for Phase II.
Phase II Treatment
Phase II treatment is coordinated by the treatment manager(in the DS3 clinic) or comprehensive care faculty member(in the DS4 clinic) who may delegate supervision of the process to restorative(DS3) or prosthodontic faculty member(DS3 or DS4) as needed. It is the responsibility of the treatment manager to ensure continuity of Phase II care. It is also the responsibility of student and faculty member to ensure that routine periodontal and caries prevention (recall and maintenance) is kept up-to-date during Phase II treatment.
CLINICAL POLICY FOR FIXED PARTIAL DENTURE
Restorability Considerations for Crowns and Fixed Partial Dentures
General rules for determining the restorability of a tooth with a crown or onlay may be found in the student text, Rosensteil, Land, Fujimoto, Contemporary Fixed Prosthodontics, 3rd Edition, and selected reviews from the literature. A brief review follows:
1. Disease control must be established.
2. Crown/root ratio should approximate 1/2. When 1/3 of the tooth root is exposed, 1/2 of the
support is gone and forces are magnified by the fulcrum location.
4. A minimum of 3mm of prepared crown height(opposing dentinal walls if the tooth has a core) is
required for retention, even when taper is not excessive. When the tooth is short, options to
improve retention include addition of lugs(if the tooth has been treated with endodontics) boxes,
or slots in the preparation. Enameloplasty of opposing teeth, especially when it will assist in
leveling the occlusal plan or improving the occlusal scheme, is also indicated to assist with thie
requirement. Crown lengthening is the final option if adequate periodontal support exists.
5. Tissue response is best when there is adequate attached gingiva and margin placement is supragingival. In order to capture the crown margin in the impression and preserve biologic width, a minimum of 1-2 millimeters of tooth structure must be available between the crown margin and the soft tissue attachment. Special care should be taken when preparing the margin on a tooth, which has had crown lengthening. These teeth have little or no sulcus depth and placement of the preparation margin at the free gingival margin or below will encroach on the biologic width.
5. Crown margins must cover the margin on any core by 1 mm.
6. Ante's Law for fixed partial dentures states that the root surface area of the abutments must be
greater than that of the teeth to be replaced. Abutment teeth with divergent roots that are not
tilted are preferable.
7. As a single pontic becomes two, the flexure increases by 8 times. For three pontics it increases
by 27 times. Metal must be bulkier as the span increases to avoid fracture.
9. Except for the maxillary central incisor, incisor teeth generally do not provide enough root
support to act as terminal FPD abutments.
10. Cantilever fixed partial dentures are significantly less predictable than fixed partial dentures
with anterior and posterior abutments, and therefore are not appropriate for patients in the
undergraduate dental clinics.
10. Teeth treated with endodontics may act as fixed partial denture abutments when they possess
adequate tooth height. Teeth with short preparations or cast post and core make poor terminal
abutments for fixed partial dentures. If a tooth treated with endodontics is questionable, better
to recommend removal than to compromise the final bridge.
11. If pre-existing problems with an uneven occlusal plane cannot be corrected easily with selective
enameloplasty and/or endodontics with extensive tooth reduction, and it is not feasible to
correct the problem orthodontically, the patient should be referred to the faculty practice or
private sector specialist.
Undergraduate Clinical Policy for Management of Fixed Partial Dentures
1. All fixed partial dentures must include the team of specialist and generalist in designing
any bridge up to 4 units.
2. Five-or-more-unit fixed partial dentures, any bridge involving a telescopic crown, precision
attachment, or any pier abutment FPD may be done in the DS4 clinic under the supervision of
designated faculty only. Patients who elect this care must be available during specific clinic
hours. If the patient is unable to accommodate the limited schedule, he/she must be referred to
the faculty practice or private sector.
3. Implant-supported fixed partial dentures are provided in the undergraduate clinic within the
scope of the implant elective program only. Generally edentulous patients and those requiring
single tooth replacement are candidates for the program. Consultation with the course director
of the elective program, is required for patients who wish more information about dental
implants.
4. Students must provide mounted casts, custom trays (2 trays), and a vacuform shell for fabrication
of the provisional restoration at the first appointment. If a bridge preparation is to be initiated,
trial preparations in stone must be presented to the supervising instructor at check-in. If a canine
tooth is being crowned, a custom incisal guide table is required also.
5. Resin-bonded fixed partial dentures are not provided in the undergraduate clinic. Patients who
elect this treatment must be referred to the AEGD Program, Faculty Practice, or the private sector.
6. Inlays/onlays may be done when the student has completed at least one crown restoration. The student must arrange to work with a pair of faculty members who can design the restoration with appropriate margins, and assist the student with practice preparations on the stone models. Students must provide the same trays and vacuform shell as for any fixed restoration.
Clinical Procedures for Fixed Partial Denture
Post and Core Restorations
Chamber-retained cores can provide excellent support when a tooth treated with endodontics has adequate dentinal wall support.
Teeth retaining two opposing walls of dentin ferrule(3mm in height and at least 1mm thickness) after crown preparation will provide adequate retention for the core material and may be restored with undercut retention only. Silver amalgam is the material of choice for core build-up due to its inherent strength but resin composite may be used when three walls of dentin remain.
Pin retention may be indicated for core support in vital teeth when undercut preparation is inadequate.
Post retention is required when there is inadequate dentinal wall support remaining to retain the core. Evidence from the literature supports use of the cast post and core in teeth with large tapered canals (anterior teeth and lower first premolars) and prefabricated posts (stainless steel posts) in teeth with narrow straight canals (two-and three-rooted molars and premolars). The advantage of the prefabricated post is that it can be fitted to the narrow non-tapered canals of molars and premolars. Also, multiple posts are recommended in a single molar or premolar tooth with root canals of different paths of draw when a single post would be shorter than the ideal. Cast post and cores may be fabricated with the direct (resin-fabricated post and core pattern) or the indirect method, employing impressions and mounted casts. Attention must be paid to any supragingival anatomy, since the core portion must draw with the canal anatomy. For cores in vital teeth, silver amalgam is the material of choice, but resin composite(Luxacore) may be used when three walls of dentin will remain after crown preparation. Resin composite core material may also be used for block-out of undercuts. Glass ionomer materials, including Ketac silver, are unacceptable as core materials as they possess inadequate strength.
Crown and Margin Design
All metal crowns, single and multiple splinted units and fixed partial dentures:
· Crown margins for all metal full coverage restorations will be a chamfer design.
Single-unit porcelain/metal crowns:
Porcelain-to-metal crowns may have:
· Chamfer all around with a metal collar at the facial margin.
· Chamfer at the lingual margin and shoulder and bevel at the facial margin with a metal collar at the facial margin.
· Chamfer at the lingual margin and a porcelain butt shoulder margin facially for teeth which require special esthetics.
(This option has a separate procedure code and a higher fee due to the complexity of the laboratory techniques required in fabrication of the crown. Teeth with cast post and core restoration are not candidates for the porcelain butt margin design.)
· Porcelain-metal margins on porcelain-metal crowns are designed to leave lingual and occlusal surfaces in metal.
· Full porcelain occlusal coverage is not provided on a routine basis in the undergraduate clinic. Patients who require this care are best referred to faculty practice or the private sector.
· Guiding planes for crowns acting as RPD abutments will be in metal.
Multi-unit porcelain/metal crowns:
Multiple porcelain butt shoulder margins on fixed partial dentures create many problems in fitting the restoration to the teeth and are too difficult for the undergraduate clinic. If multiple porcelain shoulder margins are required to satisfy the patient, referral to the AEGD, faculty practice or private sector is required. If a single anterior abutment in the upper arch is an esthetic concern due to high lip line and patient concerns, the faculty team of prosthodontist and comprehensive care or treatment manager faculty member may elect to use a single butt margin if they believe the tooth preparations will have adequate length and parallelism to support an accurate fit.
All-porcelain single-unit restorations:
The faculty team which includes prosthodontist and comprehensive care faculty member or treatment manager may consider single-unit all-porcelain restorations, including veneers, when patient indications are ideal and the student demonstrates previous competency at routine crown and bridge procedures.
Impressions
Impressions are made in a custom tray in light (syringed) and heavy-body (tray) polyvinylsiloxane.
Posterior triple trays may be used for a single unit when:
(1) a full compliment of teeth is present in both opposing quadrants
(2) the student has had previous experience with the custom tray technique
(3) the tray fits the patient allowing full closure into ICP
(4) the prepared tooth is not the most distal tooth in the arch
(5) the prepared tooth is not an abutment for a removable partial denture
(6) the prepared tooth is not one of the 6 anterior teeth
Basic tissue control is accomplished with cord and hemostatic agent (Viscostat). In selected cases when hemostasis cannot be achieved with this system and the patient has no history of hypertension or the use of contraindicated medications, epinephrine-impregnated cord may be used for tissue control. The epinephrine cord and compatible hemostatic agent (Hemoban) are available in the dispensary for instructor check-out only and each tub includes a list of all contraindications including medications. Use of epinephrine cord requires close supervision by the instructor. Use of the Viscostat from the basic kit with the epinephrine-impregnated cord will cause the gingiva to become black in color, which takes some time to reverse itself. Be careful not to mix the two systems.
Jaw Relations
Bite Registration:
Hand articulation in ICP is routine for mounting casts for fixed partial denture. A PVS bite registration may be sent to the lab as a reference.
If the prepared tooth is the most distal tooth in the arch, an acrylic resin registration is required.
Surveyed Crowns for Removable Partial Denture:
The most difficult jaw relationships involve surveyed crowns for distal extension partial dentures. Record bases with wax rims are required to mount the partially edentulous casts. It will be necessary to have the laboratory pour two casts from the impression. The first pour will be pindexed, so that the die can be trimmed and the crown margin fabricated and verified on the die. Due to the technique used for pindexing, the soft tissue ridges are mostly lost in the process, and this makes fabrication of a stable record base impossible. The cast made from the second pour is fabricated without the pindex and the prepared tooth and ridge relationships are fully reproduced. A stable record base may be fabricated on this cast.
The cast with prepared tooth and record base can be mounted to the opposing cast using the record base and PVS registration. Student and faculty supervisor will tripod this mounted cast. The technician can then develop the wax-up of axial contours and occlusion on the mounted cast, and then transfer it to the trimmed die from the pindexed cast to finalize the margin in wax prior to casting. The student will be required to set opposing and adjacent resin replacement teeth, if absent, prior to crown fabrication so that the technician can produce a crown which will provide the correct tooth size, fit into the desired occlusal plane, provide for balanced occlusion, if needed in the final reconstruction, and correctly match the color of the final replacement teeth
Occlusal Scheme:
Canine dis-occlusion is the routine occlusal scheme for fixed partial denture against natural dentition.
Full balanced occlusion is required when crowns and bridges oppose a complete denture.
If the canine tooth will be prepared for a crown restoration, a custom incisal guide table must be prepared from the diagnostic mounting prior to tooth preparation so that the laboratory can recreate the original canine dis-occlusion.
If there is a missing canine tooth in the arch associated with the prepared tooth or the patients occlusion is not supported by canine guidance, occlusal analysis is required. The occlusal scheme must be pre-determined during the original design appointment with peer review (supervising faculty and prosthodontist consultant).
Laboratory Prescriptions
Laboratory prescriptions require the peer review and signature of two faculty members. Sample prescription forms are available in each clinic, which include suggested materials for laboratory use. Quality assurance checks are done at both the Outer Drive and UHC locations. When a problem with a case for the laboratory is identified, it is returned to the student. The student is required to return the case to the faculty supervisors for management of the problem. Students may not authorize the lab to makes changes and must have faculty assistance whenever the laboratory has questions or problems with a case.
Olson Dental Laboratory and Dental Art Laboratory both provide crown and bridge services to the undergraduate dental clinic. Survey crowns for partial denture abutments must be sent to Dental Art Laboratory only. Phone numbers are available in all clinics and at the dispensary.
Sequence of Treatment
Metal try-in is required for all fixed partial dentures. Three-unit bridges may be tried in as one unit. If the fit is incorrect, the bridge is sectioned and a solder index is prepared. Sectioned 3-unit bridges or bridges of 4 or more units must be trial-fitted in sections and a solder index made in acrylic resin. A pick-up impression in PVS over the solder index is then sent to the lab for soldering. When a pick-up is done, a second metal try-in is required prior to porcelain application.
Cementation
Cementation of crowns and bridges is done with resin-reinforced glass ionomer cement. The machine-triturated material is used for single units, and the hand-mixed version is available for multiple units to allow for better control of the setting time. Polycarboxylate cement and zinc phosphate are available at the discretion of the supervising faculty member.
CLINICAL POLICY FOR MANAGEMENT OF REMOVABLE PROSTHESES
Resin Replacement Teeth
A less expensive tooth (Classic) is supplied by the dispensary for interim complete and partial dentures. Dentsply IPN Portrait Teeth are used for definitive removable prostheses.
Students are required to set the 6 maxillary anterior teeth for all patients. For the first three clinical cases, the student is required to set all teeth. After the first three cases, the student may delegate setting of the lower anterior and posterior teeth to the extramural laboratory. When the laboratory will be setting the teeth, retromolar pads and midlines must be marked for the technician. Full try-in with the patient is always required before denture processing at the laboratory.
Immediate Dentures/Pre-prosthetic Surgery
1. Immediate denture service may be provided with both interim and definitive dentures. Fabrication of prostheses is delegated to the dental laboratory. Students do not fabricate any prosthesis, including those used for single tooth replacement. Two-stage surgery and the same techniques and procedures are required for fabrication of both interim and definitive complete dentures. At the Outer Drive Campus, all immediate placement dentures and surgical stents for pre-prosthetic surgery must be disinfected and delivered to Oral Surgery 24 hours prior to the surgical appointment.
2. Consultations must document that the patient was informed of the probable need for a reline
after a year of healing and the probability of several "tissue conditioning" relines between the
time of surgery until the permanent reline after one year.
3. Clear plastic stents are required for immediate denture service and pre-prosthetic surgery. An
acrylic vacuum-formed stent may be fabricated by the dental laboratory at the boil-out stage
when the immediate denture is being processed by the laboratory. If no prosthesis will be
delivered at surgery, the student will fabricate a clear vacuformed stent on a duplicate of the
adjusted cast. A special stent material is available at the dispensary for this purpose. The coping
material used for crown temporization is too thin, and will not be accepted.
4. Students must request faculty assistance in setting teeth and preparing casts for surgery and
arrange for prosthodontic faculty assistance at surgery prior to making the surgery appointment.
The faculty member who assists the student with the cast adjustment must be available to
supervise the pre-prosthetic surgery and/or denture placement. It is the student's responsibility to
organize this with the faculty.
Overdentures
Overdentures may be treatment planned for bone preservation when esthetic compromise will not follow, severe undercuts will not be created, and disease control can be established and maintained for the prospective overdenture abutments. Restorations of overdenture abutment teeth will be amalgam plugs. More complex restorations are beyond the scope of the undergraduate clinic.
Definitive Removable Partial Denture
1. Design
Removable partial dentures are designed with biomechanical principles, including the RPI design for the distal extension abutment. A wrought wire retentive arm of 18-gauge platinum-gold-palladium wire may be used as a substitute for the I-bar when soft tissue undercuts preclude the use of the I-bar. (Refer to handout, The KISS Principle for RPD in Clinic Bays for review of design policy)
The following situations are not acceptable for removable partial dentures made in the undergraduate clinic. Patients should be referred.
· Partial denture which requires lateral incisor as primary abutment tooth.
· Precision attachment, labial bar, swing-lock, or clasp-free definitive RPD
· Use of a cast post/core tooth as a primary abutment tooth.
· Vitallium occlusal coverage.
2. Mouth Preparation
When an abutment tooth lacks appropriate contour for retention, it is often possible to bond resin composite to the tooth to create the necessary undercut. A full crown restoration may be used to supply contours and rest preparations. Rest preparations should provide a positive stop (1/2 depth of #6 round diamond) and be without undercuts. Incisal rests on mandibular canines and cingulgum rests on maxillary canines may be used when there is no occlusal interference.
3. Altered Cast Impressions
For distal extension partial dentures it is necessary to capture all landmarks (buccal and lingual extensions, hamular notches and retromolar pads) in the master cast impression. At the jaw relations appointment, record bases may be fabricated and the fit and stability of the bases evaluated. If the fit is acceptable and the framework and bases do not rotate around the fulcrum, the student may progress to the jaw relations. If the bases are short of the landmarks or the base and framework rock from anterior to posterior, an altered cast impression must be made and the impression and master cast sent to the dental laboratory for correction.
5. Dental Laboratory
Definitive frameworks for Removable Partial Denture are sent to Dental Art laboratory only. Resin processing for cases with any framework must go back to Dental Arts for processing of the resin also.
Removable Prosthodontic Procedure Steps
Definitive and Interim Complete Denture
1. Student fabricates diagnostic casts from Alginate impressions in metal edentulous trays or stock
trays.
2. Student fabricates custom Triad trays with minimal wax relief as demonstrated in preclinical
complete denture.
3. Student captures peripheries with compound and takes PVS light-body wash final impression.
4. Student fabricates master casts in dental stone.
5. Student fabricates Triad record bases with wax occlusion rims.
6. Student establishes occlusal vertical dimension on wax rims, uses a facebow transfer to mount
the maxillary cast and mounts the mandibular cast in centric relation.
7. Student sets maxillary anterior teeth with patient/faculty approval in clinic; student/lab sets
lower anterior teeth and posterior teeth without patient.
8. Full try-in with patient.
1. Vertical dimension, denture base extensions, location of occlusal plane, centric relation,
and esthetics are verified.
2. Instructor verifies vibrating line with student and patient.
3. Student draws posterior palatal seal on cast which is verified by the instructor before
and after carving of the cast for a mechanical post dam.
4. Instructor evaluates balanced occlusion before signing the laboratory prescription.
5. Peer review of the prescription and clinical materials by a second faculty member with second signature is required.
9. Student fabricates occlusal index.
11. Case sent to the dental laboratory on articulator. Two signatures and peer review required.
Laboratory waxes gingival contours, invests and processes denture, removes from flask, and
polishes dentures.
11. Dentures returned to student. Student fabricates remount casts and mounts maxillary denture
with occlusal index on semi-adjustable articulator.
12. Student delivers dentures to patient, which includes a clinical remount. If this is done as a
competency examination, everything must be completed in a single 3-hour appointment.
13. Student sees patient in 24 hours and PRN for denture adjustments.
Definitive Removable Partial Denture
1. Student makes preliminary Alginate impressions poured in dental stone for diagnostic casts.
2. Student fabricates Triad record bases with wax occlusion rims as necessary for accurate
mounting.
3. Student performs diagnostic mounting on semi-adjustable articulator with facebow in ICP.
(unless denture opposing; then casts mounted in centric relation)
4. Student surveys cast with referral to diagnostic mounting to establish RPD framework design.
Blue Partial Denture Design form from initial treatment planning activities reviewed, approved
and signed by faculty with design and mouth preparations listed.
5. Student performs mouth preparations: enameloplasty for guide planes and rest seats and
resin composite bonding for undercut fabrication. Alternatively, full crown restorations have
previously been fabricated for abutment teeth with ideal contours.
6. Student makes a custom Triad tray for the master cast impression. Wax relief with baseplate wax
is block out of all undercuts, a scant layer of wax over the edentulous ridge, and 2-3 layers of
wax over remaining teeth. No occlusal stops.
7. Student border-molds as needed and makes the final impression with light-body PVS syringed
into rests and medium-body PVS in the custom tray.
7. The master cast is fabricated by the dental laboratory(2 signatures required) in improved stone and returned to the student.
9. Student tripods the master cast and sends the diagnostic cast with framework drawing, the
opposing cast if not a denture, and the prescription form with instructions. Two faculty
signatures and peer review required.
10. Student tries the framework in the patient, adjusting as needed. Record bases are fabricated for
distal extensions on the framework and framework with bases is tried in the patient. If no rock
is present around the fulcrum line and bases are fully extended and cover retromolar pads and
hamular notches the student may proceed to jaw relations. If the framework with bases rocks or
extensions are inaccurate, an altered cast impression must be made. Trays for the altered cast
impression are fabricated on the framework in Triad using one layer baseplate wax relief.
Compound is used to mold tray peripheries and a wash impression is made in light-body PVS
with the framework fully seated.
11. Jaw relations are made with facebow transfer using a semi-adjustable articulator. The
mandibular cast is mounted in ICP unless the partial denture opposes a complete denture and
will be mounted at centric relation.
12. Student/laboratory sets teeth. Full try-in with patient as per complete denture procedures above.
13. Two signatures required for the laboratory prescription. Dental laboratory waxes gingival contours and invests and processes prosthesis. Laboratory polishes prosthesis.
14. Student places partial denture attending to base stability, flange extension, framework/base fit,
and occlusion. Occlusion is adjusted with the patient unless the partial denture opposes a
complete denture and a clinical remount is required.
15. Patient is seen for adjustment at 24 hours and PRN.
Interim Partial Dentures
1. This prosthesis may be fabricated on a well-extended Alginate impression by the dentqal
laboratory. If multiple attempts to obtain an impression in Alginate with fully extended borders
have failed, a custom tray and polyvinylsiloxane may be necessary to capture an accurate
representation.
2. Jaw relations are made in ICP with a facebow on a semi-adjustable articulator unless
a denture opposes and correct vertical dimension and centric relation are required.
3. Student sets the anterior teeth with the patient.
4. Student sets remaining teeth as per complete denture procedure (see above).
5. Full try-in. Faculty peer review and 2 signatures required for the prescription.
6. Laboratory waxes and fabricates interim RPD; wire clasp retention is optional.
7. Student places prosthesis with 24-hour and PRN adjustments.
Immediate Insertion Prostheses (Interim CD, Interim RPD, Definitive CD)
1. Immediate complete dentures (definitive and interim) are made in a one- or two-part tray. PVS
is used for the one-part tray or PVS and Alginate for the two-part tray. Interim partial denture
impressions are made as described above.
2. Student adjusts cast and sets anterior teeth with the assistance of the faculty member for all
immediate placement prostheses.
3. Student arranges faculty supervision for the surgical appointment with faculty and they develop a
plan for the surgical appointment. Stents and prostheses must be in Oral Surgery 24 hours prior
to the surgical appointment.
4. The dental laboratory must be directed to fabricate a clear surgical stent at boil-out of the
immediate prosthesis for use at surgery.
6. If the prosthesis is an interim complete denture or an interim partial denture, clinical remount
after initial healing is optional. If the prosthesis is a definitive complete denture, clinical
remount must be done after initial healing (Generally within the first 4 weeks after surgery.).
