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101 Cards in this Set
- Front
- Back
What functional morbidities result if a large maxillary defect is not obturated effectively? |
• Speech is hypernasal
• Leakage of the blous and fluids into the nose • Mastication efficiency is compromised. |
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When a large maxillary defect is anticipated secondary to resection of a large tumor, several alterations at surgery are suggested that will enhance the prosthetic rehabilitation. List the three most important and why, in each case they are important? |
1. Skin grafting the defect -- enhance retention |
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It is now possible to close large maxillary defects with free vascularized flaps. Why is this practice contraindicated in most patients? |
• Maintain access to the defect because it facilitates retention, stability, and support |
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Implants are not recommended in patients scheduled to receive radiation therapy after their surgical resection. Please explain.
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• Back scatter/dose enhancement phenomenon
o Radiation is reflected off of the implants and scatters secondary electrons to the surrounding tissues which render the bone in a 1 mm radius virtually non-vital |
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Tissue bars used to retain maxillary obturator prostheses in edentulous patients should be implant assisted. Please explain.
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• Implant supportedexcessive occlusal loadsmicrodammagebone resorptionincrease porosity of bonemagnification of excessive loads
• Implant assisted o Allows implants to facilitate retention and stability but not be the primary means of support o Minimizes lateral torquing forces on implants(thus implant overload) and directs forces along the long axis of the implant o Allows prosthesis to be compressed into mucoperiosteum in extension areas and allows tissue to absorb occlusal forces |
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It is not possible to obtain peripheral seal with a complete denture and obturator in an edentulous patient with large defects. What phenomenon contributes to peripheral seal in normal patients? |
• Atmospheric pressure |
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The acid etched implants surfaces are superior to the original machined implant surface. Please explain! |
• Acid etched
o Machined surfaces less bioreactive o Better initial anchorage o Higher BAI o Bone deposited is hard/stiffer |
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It is often advisable to splint abutment teeth adjacent to a large edentulous space such as a maxillectomy defect. Please explain!
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• Splint when teeth are:
o Periodontal and Endodontically compromised o Provides larger root area and support Central + Lateral if central is adjacent to edentulous space, centrals roots are short and conical Proved to extend the life of teeth if patient has good plaque contron |
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Retention of a maxillary obturator is critical to its function. What oral functions are compromised if retention is suboptimal? |
• Speech is hypernasal
• Leakage of bolus and fluids into the nose can occur • Mastication efficiency is compromised because the tongue is preoccupied with keeping the obturator in position. |
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In dentate patients retention for the obturator prosthesis is achieved by what means? |
Retention is provided by engaging the lateral wall of the defect and engaging the remaining dentition with a RPD casting. |
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Why is the “I” bar considered the retainer of choice on abutment teeth adjacent to a maxillectomy defect? |
1. Better esthetics
2. Maximum natural cleansing action 3. Passive functional movement of the extension prosthesis 4. Minimal tooth contact 5. Exact placement of retention contact 6. Minimal interference with natural tooth contour |
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What biologic mechanisms are set in motion when an implant is over loaded?
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Osteocytes in the trabeculae send signals to the marrow which causes the remodeling response. Old bone is removed and new bone is laid down to replace the damaged bone. The deposition of bone does not keep up with the breakdown of bone which causes impairment to the anchorage bone of the implants. |
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What is the difference between an implant assisted tissue bar and an implant supported tissue bar?
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An implant assisted tissue bar shares the occlusal forces with tissue bearing surfaces. An implant supported tissue bar bears all the occlusal forces.
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What is the purpose of the rest on the implant assisted tissue bar design used in edentulous maxillectomy patients?
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The rests control the axis of rotation and allow the ERA attachments to function vertically as designed. The rests serve to direct most of the occlusal forces axially.
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What is the purpose of altered cast impressions? |
The altered cast technique ensures maximum coverage of edentulous areas.
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Implants in edentulous maxillectomy defects achieve much lower success rates than achieved in normal patients. Why? |
The success rates are lower because in patients with defects there are less options for implant placement and often times the premaxilla is missing or partially missing, so the less desirable areas are used in those cases.
55% success rate. older (less one, co-morbidities), smoker, linear configuration leads to more implant overload. |
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In edentulous maxillectomy patients implants are placed in the tuberosity only as a last resort. Please explain.
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Generally only 1 or 2 implants can be used. It’s very difficult to get primary stability which leads to failure of osseointegration. ( lease bone loss seen, likely due to solidarity (most in premaxilla) but still poor bone quality. If used, use O ring attachement for multiple axis of rotation. |
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What are the principles of partial denture design? Do they apply to patients with maxillectomy defects? Please explain. |
All the principles of RPD design ( retention, stability, support) apply to patients with maxillectomy defects & more important. |
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What are some of the lessons we have learned when employing implants in edentulous patients with maxillary defects?
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O ring type (multiple axis of rotation) & ERA with occlusal rest on bar--> most favorable stress distribution. 1. Implants should not be the sole means of retention, stability, and support |
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Physiologic adjustment of RPD frameworks is particularly important in maxillectomy defects because of the long lever arms and increased movement. What is the purpose of physiologic adjustment?
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complete seating of the framework and non-binding movement |
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What are some of the lessons learned from our experience using implants in free vascularized flaps?
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1. NO Immediate placement of implants at the time of Md reconstruction--> difficult for good anchorage and immobilization |
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How can these lessons be applied to improve the care of our conventional edentulous implant patients?
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The same principles apply to the conventional edentulous implant patient as they do to the resected implant patient.
Bone necrosis from wearing dentures: if new 1st time denture after radiation -- higher risk. |
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Prior to free vascularized flaps oral defects secondary to removal of tongue – floor of mouth cancers were closed primarily. What were the functional morbidities that resulted from this practice? |
o Speech Articulation
o Loss of tongue bulk and control o Control of Saliva o No lip seal o Altered vestibules o Motor/sensory deficits o Swallowing o Bolus manipulation o Sensory/motor deficits o Mandibular deviation o Soft tissue/bony defects o Mastication o Bolus manipulation by tongue compromised o Sensory/motor deficits o Mandibular deviation o Cosmetics o Mandibular deviation o Soft tissue and bony defects |
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Implants placed in fibula free flaps have a very high success rate. Please explain why the rate is so high! |
o Thick cortical layers enables excellent primary stability, -->osseointegrate. |
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The vertical dimension of occlusion is often closed and the occlusal plane lowered in patients restored with resection dentures. Please explain why!
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o Facilitate the interaction of the tongue with the palatal structures during speech and swallowing
o Position the bolus onto the occlusal table |
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The neutrocentric concept occlusion is often used in resection dentures. What is the neutrocentric concept of occlusion and when is it employed in conventional edentulous patients?
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o The neutrocentric concept of occlusion is when all posterior and anterior teeth are set on the same plane of occlusion, with the exception of the lateral incisors (which are slightly higher for esthetic purposes).
No verticla overlap of anteriors, all teeth onsame plane except lateral incisors. |
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What are some of the challenges we need to overcome when making resection dentures in patients with lateral discontinuity defects of the mandible? |
1. Loss of Md bearing surface |
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What are some of the potential benefits derived from use of resection dentures.
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o Restore facial contours
o Restore lip seal o Mastication |
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What are the three most important prognostic factors when predicting whether a patient will be able to masticate reasonably effectively with a mandibular resection denture. Explain the significance of each of these factors |
1. Tongue status --tongue manipulates bolus (and Md denture and sometimes the Mx denture) |
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Lip plumpers are often added to labial flange of mandibular resection dentures. Why?
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o Improve lip contours
o Prevent lip biting o Permit lip seal thereby improving salivary control. |
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In edentulous patients treated for tongue-floor of mouth tumors it may be difficult to fit the patient with a well retained maxillary complete denture. Please explain!
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o Buccal pouch negatively impacted by presence of a residual ramus fragment on resected side or excessive deviation of the mandible on normal side difficult to extend the denture around the buccal pouch and over the hamular notch into PPS area.
o Radiation induced xerostomia which reduces peripheral seal. |
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Silicone liners should not be used with complete dentures in irradiated patients. Please explain!
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Silicones exhibit decreased wetability + reduced salivary flow -- increased friction at the denture-mucosa interface during function. 8/25--> ST necrosis |
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Besides the usual exam findings (tongue position, floor of mouth contour etc) what findings are uniquely important in irradiated patients when considering fabrication of complete dentures
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(MSBST)
•Condition of oral mucous membranes •Scarring at the tumor site •Contours of the bony bearing surfaces, presence of bony undercuts •Salivary flow rates •Trismus |
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What radiation delivery findings are important to consider when considering an irradiated edentulous patient for complete dentures?
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o Field of radiation
o If more posteriorless likeliehood of the Mn bearing surface was irradiated o If tongue/floor of mouth cancerincreased likelihood that Mn bearing surface was irradiated o If tumor was in floor of the mouthhigh risk of scarring in the areas which the denture flange may extend tohigh risk of mucosal perforation o Dose to Mn bearing surface o Less than 65000 Cgy low risk of ORN o More than 65000Cgyincreased risk of ORN especially w/ mucosal perforation |
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In irradiated patients what criteria are used to selected posterior tooth forms?
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• Coordination of the patient ( not based on irradiation) |
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Following cancerocidal doses of radiation boney changes result which may impair osseointegration. What are those changes? |
VOFOR |
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The acid etched surfaces are more bioreactive than machine surface implants. Will they (acid etched surfaces) be any more successful in irradiated tissues? Please explain.
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No. The major problem in the irradiated patient is loss of vasculature and with it the loss of osteoprogenitor cells (stem cells) in the marrow. Initial biologic events leading to deposition of bone on the surface of the implant is compromised. |
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Implants can be used in most edentulous patients who have been treated for oral cancer. Why is this statement true? Please explain your answer. |
o Mandible |
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In the future we will encounter an increasing number of patients with osseointegrated implants who present with oral cancers requiring radiation therapy. If a patient presents with implants in the posterior mandible and this area is to receive 7000 cGy, what would you recommend? Please explain the rationale supporting your recommendation.
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HBO (hyperbaric oxygen?), Recommend abutments and superstructures be removed and skn/mucoa closed over implant fixtures prior to radiation. I would elect not to reexpose implants and replace the prosthesis as bone exposure secondary to infection can lead to osteoradionecrosis. |
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Summarize the tissue changes observed in animal studies when implants are placed in irradiated tissues and note the clinical ramifications.
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a) More woven bone at the interface may affect the quality of anchorage and the load bearing capacity of the implants. |
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Based on the tissue changes noted above what clinical assumptions can you make regarding the use of implants in irradiated tissues? |
1. In the mandible at higher doses (above 6500 cGy with conventional fractionation) the risk of osteoradionecrosis becomes significant. |
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The bone anchorage achieved with acid etched implants is superior to that achieved with machined surface implants. Please explain why this is the case.
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o Specific genes are expressed which accelerate and enhance the deposition of bone on the surface of the implant
o Bone deposited is harder and stiffer. |
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What are the benefits derived from implant retained prostheses?
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Improved retention and stability |
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Please discuss the differences between craniofacial implants and intraoral implants?
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They are the same type. They are titanium and are designed to osteointegrate. But the craniofacial implants are shorter 4-5mm
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What anatomical locations are best for implant placement in the nasal, orbital, and auricular prostheses? Why are magnets used in the orbital prosthesis as opposed to Hader Clips?
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Nasal: floor of nose, glabella Orbital: supraorbial rim |
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What are the steps in fabricating an implant retained prosthesis for prosthetic rehabilitation?
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Make impression with elastic material Process the applicance |
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According to Chang et al, treatment satisfaction of facial prostheses was found to be superior in which aspects of life?
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Home, eating, exercise, perspire Home>perspiration>eating>exercise |
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1. A patient is referred to you prior to radiation therapy to determine whether or not teeth are to be extracted prior to radiation. What criteria should be considered before making decisions regarding extraction of teeth? In each case indicate whether it would make you more aggressive or less aggressive in recommending preradiation extractions. |
i. Urgency of treatment body of mandible, mandibular molars, lateral tongue, floor of mouth treated with opposed mandibular fields High posterior lateral facial fields-- low ORN risk |
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2. List those post radiation sequellae which may effect complete denture fabrication and tolerance.
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Mucositis, candidiasis, ORN, Edema, Trismus, Xerostomia. a. Mucositis – |
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3. Discuss the difference between electrons and photons (high energy) in regard to penetration, definition of fields, bone absorption and skin sparing
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a. Photon beam therapy*
Combination beam (E+P) - tx of parotid or large skin tumors.
Fields: - high posterior field (soft palate, tonsillar, nasopharyngeal)- decrease in saliva, low risk of ORN ( mand away from field) -Opposed mandible fields - HIGH risk of ORN but not as much parotid gland invovled. |
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dentulous patient is referred to you prior to radiation therapy for a dental evaluation. What information do you need to obtain from the radiation oncologist in order to make treatment recommendations?
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a. Dosage, field of radiation, type of radiation, chemo or no chemo |
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6. Therapeutic radiation is delivered in a series of fractions. Discuss the biologic phenomenon upon which fractionation is based
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series of 200cGy over 6wk period (total 6500-7200cGy): allows dor reoxygenation of tumor cell (hypoxic) recovery.
a. Allows for reoxygenation of hypoxic tumor cells- most tumor cells are anoxic, reoxygenation allows oxygen to reach the anoxic cells and make the more radiosensitive |
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7. Patient “A” receives 6900 cGy via the linear accelerator for a lateral floor of mouth sq. CA and develops an osteoradionecrosis adjacent to the tumor site. Patient “B” receives 5000 cGy via the linear accelerator and 3000 cGy with an iridium implant for a lateral floor of mouth and sq. CA develops an osteoradionecrosis adjacent to the tumor site. In both patients the bone exposure extends beyond the mucogingival junction. Would these two patients be treated in a similar way? If yes, outline your treatment recommendations. If no, describe your treatment recommendations for each patient. |
a. Patient A: (risk of ORN very highl both B and L plate get 6900cGy each, so they will both slough) (total 8000cGy total @ L --> slough; B/outside= only 5000cGy = will heal) |
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8. Describe some of the methods used to minimize the symptoms associated with radiation mucositis. |
a. Supportive and symptomatic
Multiple beams, bracytherapy |
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9. How would you describe to a preradiation patient the changes in taste perception they will experience during and after their treatment. |
a. Taste buds is almost completely eliminated at 5000 cGy |
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10. Define dosimetry.
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a. The purpose of dosimetry is to evaluate the amount of energy absorbed by the tissues subject to radiation. |
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11. Define brachytherapy. |
a. Radioactive sources are implanted locally within the tissues encompassed by the tumor |
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12. Describe the “late affects” of cancerocidal doses of radiation on the oral mucous membranes histologically. What are the clinical implications of these changes?
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(Reproductive DNA damage (functional cell)-->trauma-->proliferation (reproductive death)-->Trauma induced (delayed) necrosis. a. Late effects: |
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13. Chronic Candida albicans infections are common after a definitive course of radiation for an oral cavity tumor. Why is this infection common and how is it best treated? |
a. Changes in the oral flora - The numbers of fungal organisms increase 100 fold |
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14. Describe the microfloral changes in the oral cavity following a definitive course of radiation for head and neck tumors. What is the clinical significance of these changes? |
a. Changes in the oral flora - fungal 100x increase |
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15. Describe the histologic changes seen in bone after a definitive course of radiation. What is the clinical significance of these changes? |
a. The mandible absorbs more radiation than the maxilla because of its increased density. iii. Bone is nonvital--> no remodelling |
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16. Both amalgam and composite resins have used in post radiation patients. Please discuss the pro’s and con’s of each material when used in this patient population.
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a. Amalgam -- Preferred |
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17. What key facts are important to consider when prescribing topical fluoride for post radiation patients
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i. NO Acidulated phosphate fluorides are not recommended for daily applications because its low PH: ii uptake confined to 30-50 microns, penetration compromised with plaque, most is lost within 24 hrs. daily applications are neeeded, |
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18. What are the strategies employed to maintain the dental health of post radiation patients?
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a. Topical fluoride applications |
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19. Why are radical alveolectomies recommended when extracting teeth prior to radiation that are within the proposed field of radiation?
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a. Rationale |
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20. Discuss the issues and clinical procedures that it is necessary to keep in mind when extracting teeth prior to radiation that are in the proposed radiation fields.
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a. Selected teeth - not all healthy teeth should be extracted (actually increase rate of ORN), treated conservatively with mand retention ( ORN 2' to pre-radiation ext is 10%) ii. Check Dental Ds factors (condition of teeth, compliance, max/mand - max=better/ 2% ORN risk & good healing) & Radiation f (urgency, fields, mode, dose (>6500, prognosis) |
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21. Healing times following preradiation extraction and initiation of radiation therapy is dependent on several factors. List them. |
i. Nature of the infection associated with the dentition and the surrounding bone – more infection requires more healing time |
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22. Discuss the impact of radiation fields upon the risk of osteoradionecrosis and radiation caries
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a. High posterior fields
i. Risk of caries is high ii. Risk of osteoradionecrosis is low b. Opposed mandibular fields i. Risk of caries is reduced ii. Risk of osteoradionecrosis is high |
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23. Please provide examples of the so-called “secondary effects” of radiation therapy on oral tissues.
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a. Muscle wasting - Secondary to changes in the fine vasculature |
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24. Discuss the pro’s and con’s of the use of pilocarpine in patients with postradiation xerostomia.
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a. Requires residual salivary gland parenchyma to be effective |
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25. Many patients suffer from severe trismus following radiation treatment. What is the most effective method of treatment of trismus in this patient population? |
a. Treatment consists early initiation of of exercise and use of dynamic bite openers prior to fibrosis setting in
Therabite device? tongue blade |
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26. What is the role of hyperbaric oxygen in the treatment of osteoradionecrosis? Be specific! |
a. Biologic Basis
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27. Describe the early changes seen in salivary gland tissue histologically during radiation of the salivary glands. Describe the late changes histologically after radiation treatments have been completed. What are the clinical implications of these changes? |
a. Early changes - reduced flow rate, more acidic saliva- less buffering - xerostomia -->fungal infxn, caries, discomfort of prothesis. |
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28. Describe the late changes seen histologically in the periodontal ligament following exposure to cancerocidal doses of radiation. What is the clinical significance of these changes?
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a. Changes in the periodontal ligament |
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What is the criteria for pre-radiation extractions in terms of dental disease factors and radiation delivery factors?
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Condition of the residual dentition urgency fields, mode of therapy, dose, prognosis |
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What surgical procedures are completed at the time of extraction to reduce side-effects of radiation therapy?
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• Radical alveolectomy - care with lingual flap (susceptible to mishandling) • Crown amputation (impacted 3rds are not recommended due to post op bony defects), - teeth removed in segments (helps for 1' closure) - AB - 7-10 days healing before readiotherapy |
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12. DEFINE IMRT |
12. DEFINE IMRT |
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18. What key facts are important to consider when prescribing topical fluoride for post radiation patients
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a. Uptake confined to outer 30-50um |
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What are the options when a patient presents with non-restorable dental disease, ie, severe periodontal disease or advanced caries post radiation? |
• Mandibular teeth in field with dose to bone >5500cGy-->ENDO |
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What are some technical aspects of post-radiation operative dentistry?
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• Due to extensiveness of caries, not always appropriate to remove unsupported enamel.
Ag preferred. |
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What are the benefits of bisphosphonate therapy?
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– Oral bisphosphonate therapy. Paget ds |
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What precautions should you take if the patient is on bisphosphonate therapy?
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– Oral bisphosphonate therapy. Remove potential source of dent infxn and irritation b4 BP Avoid surgical procedures while on BP |
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What are some clinical manifestation of cancer?
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Pain |
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Describe the TNM system
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Size of tumor - T |
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What are some common side effects of chemotherapy? |
Mucositis / stomatitis
Nausea and vomiting Hair loss Myelosupression |
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What is the difference from direct vs. indirect stomatotoxicity?
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Direct Indirect |
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Which classifications of chemotherapeutic agents have the highest incidence of oral mucositis?
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Alkylating agents
Antimetabolites Antitumor antibiotics |
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What is the incidence and consequence of oral mucositis? |
10% adjuvant, 40% primary, 80% stem cell |
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Define induction, adjuvant, salvage, and neoadjuvant chemotherapy.
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Induction: given when no alternative treatment is available |
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If a patient of yours tells you that he/she will be initiating chemotherapy in the next couple of weeks, what should be you plan in regards to dental care? |
MD consult |
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In consulting the medical oncologist for planned dental care, what pertinent questions should you ask in the following type of care?
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– Restorative care: Neutrophils, Platelets, RBC, need for premedication
1500 N/60k P: normal tx, MD consult, AB 500-1500N/20k-60k P: emergency tx, platelet transfusion for surgery < below 500N/20k P: No Rest Tx |
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Definition of ORN
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necrosis of bone within the field of radiation of 3 months duration or longer |
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ORN most common where and which kind of patients?
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Mandible, dentulous |
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External vs. Brachy + External
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Brachy+ External high risk of getting ORN but easier to treat
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Goal or ORN treatment
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maintain mandibular continuity
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Stages of HBO treatment
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Stage I-These patients present with bone necrosis but without pathologic fracture of the mandible, orocutaneous fistula or radiographic evidence of bone resorption of the inferior order of the mandible |
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In consulting with the oncologist, he/she mentions that the patient’s blood count will be at nadir in a week. What does that mean to you? |
– Lowest count that blood cell levels fall is called NADIR. This can occur at different time for different cells, usually white and platelet reach this in 7-14 days. Red will not reach for several weeks. - Dental tx should be delayed until btw 3rd - 4th week after chemo - Emergency treatment must be done with MD consult, antibiotics, and transfusion. |
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What is the most debilitating side effect of PBSCT and BMT? |
Oral Mucositis : Mouth sores.
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If a patient of yours tells you that they will be initiating a BMT or PBSCT in the next couple of weeks, what should be you plan in regards to dental care? |
Remove all potential sources of infections |
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In consulting the oncologist for planned dental care, what pertinent questions should you ask in the following type of care? (This should include immediate post transplant and greater than 1 year post transplant)
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– Restorative care?(TI-MAC G) |
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What are common oral findings in post allo BMT patients?
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Leukemic - Lesions in the Gingiva
Graft vs Host Disease New Solid Tumors in mouth (SCC in oral cavity) |