OE L40 Implantology: Clinical Overview Flashcards
Name the indications for dental implants.
- Tooth loss which may be caused by: caries, trauma, periodontal disease, congenital absence of teeth
- Following elective surgery where implants are used to replace teeth and other supporting structures
What length are dental implants?
- Usually 8-18mm
- Some 5mm available
How can implant surfaces be modified?
- Acid etched
- Grit blasted
- Oxidised
- HAP coating (largely unsuccessful)
How do dental implants differ based on physical form?
- Narrow/regular/wide platform
- Tapered
- Parallel sided
Describe fixed vs removable implant restorations.
- Crown and bridgework fixed in place
- Removable dentures
- Removable prostheses to replace tissue lost to trauma or surgery e.g. cancer patients
What should be considered in the clinical assessment of a patient wanting implants?
- Status of their remaining dentition (e.g. caries, future treatment needs, extraction, periodontal disease, teeth of poor prognosis)
- Smoking (risk of complications e.g. periimplantitis)
- Patient should have sustained interest, good compliance, rigorous oral hygiene, regular checkups
What anatomical considerations are there for implant patients?
Consider underlying bony architecture, which may be affected by:
- Disease e.g. periodontitis, cysts
- Trauma
- Chronic bone resoprtion (pts who have had teeth absent for considerable lengths of time)
How can the available bone be examined prior to treatment?
- Clinical examination and appearance (e.g. clinical evidence of bone loss)
- Radiographic examination: intraorals, cone beam CT
What are the ideal bony measurements for an implant patient?
- There should be 1mm of buccal and lingual/palatal bone (inner and outer cortical plates)
- Implants must be placed 1.5mm from adjacent teeth
- Implants must be placed 3mm from adjacent implants
What are the associated risks/complications with dental implants?
- Infection (acute or chronic)
- Soft tissue complications e.g. loss of papillae=black triangle
- Bleeding
- Damage to adjacent teeth
- Postoperative anaesthesia or dysesthesia
What are the rates of implant failure?
- Higher rate of failure for maxillary implants
- Some research suggests 10% failure rate for the mandible, others suggest 2%
Describe the 1st stage of treatment.
1) Scalpel used to make incision and elevate flap of soft tissue
2) Guide drill at 1,500rpm (slow) to mark surface
3) Drilling protocol differs betwen implant systems, typically make a series of progressively larger holes (depth should allow the implant to be level or slightly submerged relative to adjacent marginal bone)
4) Place direction indicators if doing adjacent implants, to ensure hole is parallel
5) Place implant in prepared osteotomy site at low drill speed
Following implantation, what are the 2 possible treatment options?
1) Insert healing abutments (non-submerged implant) aka 1-stage treament
2) Cover screw inserted into implant head and soft tissues sewn over impplant and screw (submerged implant) aka 2-stage treatment
What are the 6 stages of wound healing that occur in the soft tissues overlying the implant?
- Initial injury and vascular response
- Coagulation/platelet plug formation
- Inflammation
- Repair and new tissue formation
- Re-epithelialisation
- Contraction and remodelling
Describe the inflammation to the soft tissues following implantation.
- Inflammation is a direct result of trauma
- Maximal in the first 12 hours
- Post-operative prescribing of anaesthetic and analgesics recommended
Describe ECM remodelling following implantation.
- Myofibroblasts heavily involved, express alpha-smooth muscle actin
- Cause cellular contraction (decreases bacterial ingress) which reduces wound size and gives rise to scar formation
Describe the role of collagens in wound healing.
- Provides strength to close wound and strengthens the restored gingivae
- Type III collagen found in high levels in the early wound matrix
- Type I collagen found in later stages and provides tensile strength (5% at 1 month and 75% at 1 year)
What are the 2 markers of osteoblast differentation?
- Alkaline phosphatase
- Type I collagen
Which factors induce and inhibit osteoconduction?
Osteoconduction = MSC differentiation into osteoblasts
Induced by: BMPs, VEGF, TGF-β
Inhibted by: PDGF, bFGF
What are the stages of bone formation?
- Cell migration proliferation and differentation
- Matrix maturation
- Matrix mineralisation
What are possible consequences of bacterial involvement following implant surgery?
- May cause periodontitis, which can develop into peri-impant mucositis or peri-implantitis
- Can affect cellular responses such as wound healing after surgery
What anatomical features of the maxilla are relevant to implant placement?
- Floor of the nose
- Maxillary sinus
- Incisive canal (can cause issues with insertion e.g. bleeding and instability of implants placed adjacent to this site)
What anatomical features of the mandible are relevant to implant placement?
- Inferior alveolar nerve
- Mental nerve
- Must have a 3mm clearance from implant tip to inferior alveolar nerve
What technique can be used to minimise risk of nerve damage and correct implant placement in the mandible?
- CBCT guided surgery
Describe guided bone regeneration in implantology.
- Use of membrane technology to allow for new bone growth
- Particulate bone left over from drilling, or bone substitutes, can be used as filler material for new bone growth
How can we maximise healthcare benefit of implants?
- Importance of planning: management of current disease, smoking cessation, OHI
- Importance of sequencing and co-ordination of activity
