Implants Flashcards

Question

When is implants likely failure to integrate and have a. fibrous connection

Answer 1

Likely due to lack of primary stability, type IV bone, inadequate preparation of osteotomy (over-prepa- ration of osteotomy, excessive torque when plac- ing implants in type 1 bone, poor irrigation leading to bone necrosis and infection).

Answer 2

Verify implant position with radiography (3D imaging preferred). The implant should be removed immediately if noted to encroach upon the nerve. In theory removal allows psychological therapy for the patient, pathway for escapement of debris and irritants, ease for future nerve repair, and takes pressure of the nerve (if not severed). No bone graft should be placed into the site. Steroid application to the injury site and high- dose steroids orally for a week may help reduce

Answer 3

Implant penetration into max- illary sinus of 1–2 mm has been shown to be fully covered with sinus membrane and partially by bone in animal studies. No difference in stability is noted. Penetration of 3 mm or more showed expo- sure into the sinus cavity without any coverage.

Answer 4

Usually occurs late once implants are loaded but can also happen when placing implants in extremely atrophic mandi- bles. Recommended at least 6 mm in vertical height and width required for implant placement. If there is not enough bone stock, then a bone graft is indicated. Treatment follows basic trauma principles. Treatment of the edentulous mandible may require a large reconstruction plate with consideration for bone grafting.

Answer 5

Associated with gram-negative anaerobes including P. gingivalis, P. intermedia, and Aggregatibacter actinomycetemcomitans. Symptoms include bleeding on probing, bone destruction, suppuration on probing, erythema, hyperplasia, probing depth >5 mm, mobility of implant, and swelling. Pain is normally only present in the setting of acute infection. Local debridement – exposure and cleaning with instrument softer than titanium. Consider rubber cup polisher with paste, plastic scalers, abrasive air powder treatment, and interdental brushes. 2. Decontamination – 40% citric acid with a pH of 1 for 60 seconds, chlorhexidine, tetracycline (50 mg/ml saline for 2 minutes), or application of local antibiotics (e.g.,tetracycline granules), Er:YAG or CO2 laser or 3% H2O2. 3. Surgical – open flap combination of debride- ment and decontamination with allograft/ autograft with membrane. 4. Removal of implant.

Answer 6

Osteogenic – transfer of osteocompetent cells for de novo bone formation, e.g., autografts. * Osteoinduction – bone formation by stimula- tion of host mesenchymal cells to differenti- ate, e.g., allograft, bone morphogenic protein. * Osteoconduction – providing scaffolding for new bone formation propagated by native bone. Does not contain proteins or cells, e.g., xenograft.

Answer 7

Recombinant DNA technology in Chinese ovarian hamster cells allows for transcription and collection of non-contaminated protein. * Water soluble, requiring a collagen type 1 car- rier (acellular collagen sponge) for slow release. Requires 15 minutes of absorption. * Concentration of 1.5 mg/cc mixed with sterile water (do not substitute with normal saline as too hypertonic). * Chemotactic for preosteoblasts and stem cells as well induces expression of VEGF by osteoblastsOnly on label use is currently for sinus aug- mentation or alveolar ridge reconstruction. Will have extensive edema due to influx of fluid and cells from the chemotactic and neo- vascularization activities of BMP. Allow healing of 6 months prior to implant placement. Contraindications: (1) pregnancy, (2) allergy to rhBMP or type I bovine collagen, (3) active infection at recipient site, (4) active or history of malignancy at site, and (5) skeletal immaturity. Postoperative steroids and icing of tissue may reduce the intensity of swelling.

Answer 8

PRP is a blood clot that is highly concentrated with platelets, about 1 million platelets/μL. Alpha granules in platelets secrete the growth factors that bind to transmembrane receptors to induce its effect, initiating a faster initial cellular response. Collection tube contains citrate dextrose as anticoagulant, which works by binding to calcium. The platelets are spun down either in two spins (separation spin followed with a concen- tration spin) or some manufacturers offer sin- gle spin units. Activated via the addition of CaCl2 and thrombin.

Answer 9

Platelet-rich fibrin (PRF) was developed as an improved formulation of the previously uti- lized platelet-rich plasma (PRP), to serve as a three-dimensional scaffold to biologically enhance healing. This new approach is based on the concepts that were introduced over a decade ago con sisting of a platelet concentrate without the use of anticoagulants. PRF is obtained simply by centrifugation without anticoagulants and is therefore strictly autologous. This fibrin matrix contains platelets and leuko- cytes as well as a variety of growth factors and cytokines including transforming growth factor- beta1 (TGF-β1), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), interleukin (IL)-1β, IL-4, and IL-6. These factors act directly on promoting the proliferation and differentiation of osteoblasts,

Answer 10

Class 1: Dentate. Class 2: Immediately post-extraction. Class 3: Well-rounded ridge, adequate in height and width. Class 4: Knife-edged ridge, adequate in height and inadequate in width. Class 5: Flat ridge, inadequate in height and width. Class 6: Depressed ridge with varying degrees of basal bone loss that may be extensive but follows no predictable pattern.

Answer 11

Schneiderian membrane is 0.13–0.5 mm thick and is composed of respiratory epithelium. Paired sinuses with a mean size of 15 ml per sinus. Width ~2.5 cm; height ~3.75 cm. Sinus ostium is located in superior medial sinus wall (halfway in the A-P distance of the sinus just below the orbital floor). It is usually 25–35 mm above the antral floor. It opens up to the middle meatus via the infundibulum. Underwood’s septa – fine bony projections from the floor of the maxillary sinus, which can cause two or more compartments and complications during sinus grafting. One sep- tum is present in about 90% of patients.

Answer 12

Schneiderian membrane is 0.13–0.5 mm thick and is composed of respiratory epithelium. Paired sinuses with a mean size of 15 ml per sinus. Width ~2.5 cm; height ~3.75 cm. Sinus ostium is located in superior medial sinus wall (halfway in the A-P distance of the sinus just below the orbital floor). It is usually 25–35 mm above the antral floor. It opens up to the middle meatus via the infundibulum. Underwood’s septa – fine bony projections from the floor of the maxillary sinus, which can cause two or more compartments and complications during sinus grafting. One sep- tum is present in about 90% of patients.

Answer 13

Antral pseudocyst/mucocele – should be removed/aspirated 6 months prior to lift and re-evaluated for recurrence. A relative contraindication.

Answer 14

ncision should be palatal to the alveolar ridge to reduce risk of postoperative fistula if no immediate implant is planned. A crestal flap should be utilized if an implant is planned at time of augmentation. 3. Ostectomy – thin out lateral sinus wall expos- ing sinus or window outline (quadrilateral ostectomy) to act as superior bony roof. The inferior extent should be 1 mm superior to the floor. Many surgeons now use piezosurgery to reduce perforation rate from 30% with con- ventional burs to about 7%. 4. Elevation of sinus membrane with piezosur- gery with non-cutting blade along perimeter or sinus curettes. If patient is awake, asking them to inhale allows visualization of adher- ent membrane. Check for perforations. 5. Place graft material medially to ensure adequate bulk toward the medial aspect of the sinus cavity. In simultaneous implant placement, after lifting the sinus mem- brane and preparing the implants, a graft should be placed first, then implants, and then more graft material. Materials include autogenous (gold standard, good for larger grafts), allograft, xenograft, or alloplastic. Non- autogenous grafts have similar suc- cess rates, only a small percentage lower . Placement of absorbable membrane at bony window. 7. Suture to watertight closure of flap.

Answer 15

Crestal incision to expose ridge. 3. Start osteotomy with 2 mm twist drill to 1 mm below sinus floor. 4. Guide pin placed and PA taken to ensure sub- sinus ideal position. 5. Osteotomies of different gauges are now mal- leted 2 mm higher than native bone using up to appropriate gauge of planned implant. 6. Test with Valsalva and hand mirror to evaluate sinus integrity. 7. Placement of autograft/allograft and work into sinus space created to dome sinus. 8. Placement of implant. 9. Repair incision with sutures.

Answer 16

Sinus precautions: no nose blowing for 2 weeks, sneeze with mouth open, no pressure changes such as scuba diving and use of straws or wind instruments. Antibiotic with sinus coverage (e.g., amoxicil- lin 500 mg q 8 h × 7 days), oxymetazoline 0.05% q 12 h for 3 days, saline nasal spray PRN congestion, pseudoephedrine 30 mg q 6 h PRN congestion. Allow 6 months for graft consolidation.

Answer 17

Sinus Perforation If perforation is 2–3 mm, will likely self-repair by folding over or blood clot for- mation, consider collagen wound dressing. If per- foration is 5–10 mm, consider bioabsorbable collagen membrane. If larger (10 mm >), assess possibility of using collagen membrane to com- pletely cover graft. If not possible, abort surgery and return in 3 months. At this point, the sinus will be thicker in the area of the perforation.

Answer 18

aused by overfill or migra- tion of particles, infection, or inflammation. Assess extent of sinusitis with imaging. Place on steroids and antibiotics. If no improvement, con- sult with ENT.

Answer 19

Usually resolves on its own. Attempt Epley maneuver. Anti-vertigo drugs like meclizine 50 mg PO BID for symptomatic treatment.

Answer 20

* Best to harvest lateral to midline, at least 5 mm below apex of canine. Can be done bilaterally, if larger graft is required. Preservation of anterior chin contour is recommended. * Some authors recommend grafting the harvest site with allograft/xenograft to maintain chin contour. * Allow 5 months for integration. * Second graft can be taken no sooner than 10 months from initial harves utline planned osteotomy with saw/bur of choice, ensuring to be 5 mm inferior to root tips and 5 mm from the inferior border, enter- ing into cancellous layer. Preferred area to remove bone is below lateral incisor and canine, preserving the midline region. 5. Remove graft, a curved chisel or fine osteo- tome may aid in its harvest. May harvest addi- tional cancellous bone with curettes. 6. For large grafts, place bone substitute to fill donor site. 7. Close in layers with 4-0 slow resorbing sutures deep and with 3-0 resorbable sutures for mucosa.

Answer 21

Contraindicated if highly pneumatized sinus or sinus infection is present

Answer 22

Vertical bone height of 5 mm can be expected, limitation is stretch in pedicle

Answer 23

More often used on the maxillae than mandible. * Can gain from 3–6 mm of horizontal bone. * Adequate bone height of 10 mm should be available on maxillae. * In mandibular procedure, ideally more than 12 mm above canal. Must ensure ridge in favorable position and not too medial and without concavities. Minimum 3 mm of width. After ridge split, implant should be more facially positioned, likely require custom abutments when restoring. Tapered implants best to allow for increased expansion. Consider implant with less depth to threads. Midcrestal gingival incision. 3. Minimal reflection of mucoperiosteal flap, no greater than 5 mm. 4. Use guide to mark implant position if immediate placement planned with 2.0 drill. If peak of bone present, it should be reduced. 5. Piezotome or saw used to make osteotomy, ensure angulation parallel with residual ridge for even splitting of bone. Ensure cut 2 mm away from adjacent teeth if present. 6. Spatula osteotome used for separation of cortical plates with gradually wider osteo- tomes/chisels to expand ridge. If difficult to expand, may make vertical osteotomies on facial bone at end of osteotomy to aid expansion. 7. Accomplish implant preparation with implant osteotomies (allow for more expan- sion) or implant drill if planned at this time. 8. Graft gap of osteotomy with bone graft of choice. Cortical graft may aid in keeping plates separated. Placement of collagen membrane to cover site. 9. Reapproximate tissues. 10. Allow 6 months for healin

Answer 24

Defects 6–9 mm in height are often indicated for distraction

Answer 25

Latency period (3–7 days) – mobilizing the trasnport segment too early will cause the regenerate to be formed with high levels of fibrous tissue and low bone density. Activation Period: – Rate – activation best at 0.7–1.3 mm per – day (recommendation on most distractors 1 mm/day). High distraction rates (>2 mm/ day) leads to impaired angiogenic response and fibrous bone. 0.5 mm/day carries risk for premature ossification and failure of distraction. – Rhythm – number of distractions per day. – Increasing rhythm to several cycles a day reduces soft tissue trauma and patient com- fort. A rate of 0.25 mm at 4 rotations a day, or 0.5 mm with 2 rotations a day, has shown to improve regenerate quality. Consolidation (3 months) – keep device on until seeing radiographic evidence of bone healing. This may be longer in older patients. Can place implants at time of device removal.

Answer 26

Good for large maxillary ablative defects, traumatic defects, severely atrophic maxillae, cleft palate unrepaired defects, and patient’s refusal for sinus augmentation. About 97% success rate [19]. Zygomatic implants are available in 30–52.5 mm fixture lengths, 4 mm diameter in apical 2/3- and 5-mm diameter in the alveolar 1/3 (45° tilted connection to correct for angulation).

Answer 27

sinusitis may compromise survival and should be addressed prior to placement. Patients are at a higher risk of postoperative sinus infections

Answer 28

Implant can be immediately loaded if a torque of >40 Ncm is acheived They should have cross arch stabilization.

Answer 29

Intrasinus technique – create a lateral sinus window to push sinus membrane from implant; some clinicians elect to bone graft around implant and sinus cavity. Extra sinus technique – allows more crestal emergence, reducing sinus complications, increases tongue space allowing for decreased risk for altered speech and increase space for hygiene access. Major disadvantage is mid portion of implant is in direct contact with soft tissue,

Answer 30

main disadvantages of bar attachments are the need for a large prosthetic space. There is an increased risk of mucositis and hyperplasia due to an inadequate oral hygiene under the bar. A minimum of 12–14 mm of vertical restor- ative space is required for a bar retained overdenture. Bars need to be parallel to the rotation axis, be straight, and be positioned 1–2 mm above the alveolar crest to aid in hygiene.

Answer 31

is 8.5 mm of vertical restorative space and 9 mm of horizontal space.

Answer 32

On the other hand, they have a weaker lateral stability and retention in comparison with mechanical attachments as ball or bar devices. * They are susceptible to corrosion by saliva, explaining why they are clinically less often used.

Answer 33

AP spread is defined as the distance between a line drawn between the distal sides of the pos- terior implants and a parallel line drawn When the AP spread is 1 cm or more, Branemark and his colleagues concluded that the cantilever could be extended to, but not beyond, 20 mm or up to two times the AP spread.

Answer 34

dvantages * May be indicated when inferior alveolar nerve is exposed. * Easier to maintain oral hygiene compared to a fixed prosthesis. * Longer life span of the bar since there is no movement of denture base. Disadvantages * Requires placement of at least four implants in the mandible with at least 1 cm of AP spread to support posterior occlusal forces. * The implant-connecting bars have to be bulk- ier and acrylic denture should be reinforced with metal substructure. * Increased cost, time, and need for accuracy compared to implant-retained overdenture

Answer 35

Psychological and psychosocial advantages of having a fixed prosthesis. * Increased bite force. * Patient prefers not having the palatal coverage in the denture. * Improves phonetics, appreciation of tempera- ture, and taste. Disadvantages * Needs five implants in the mandible or six in the maxilla, unless an All on 4®/tilted implant prosthesis is planned using angled implants. * May require additional surgical procedures to augment alveolar ridge or maxillary sinus, or alveolectomy to provide interocclusal space. * Significantly increases cost of prosthesis and need for accuracy. * Sufficient interocclusal space is required to allow for fabrication of a rigid prosthesis and provide space beneath prosthesis to maintain oral hygiene. * Challenge to maintain oral hygiene especially in elderly or debilitated patients.

Answer 36

Benign paroxysmal positional vertigo is a known complication of sinus floor elevation and would be my working diagnosis. I would attempt to control her symptoms with antihis- tamines such as meclizine.

Implants Flashcards

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