Extraction Site Ridge Preservation

1. Extraction Site Ridge Preservation Dentistry 664 Dr. John Walters

2. Alveolar bone loss following extractions • After tooth extraction, loss of alveolar bone is very common • about 40 to 60% of alveolar ridge height and width is eventually lost • mostly in the first two years after extraction • Maxillary anterior area at greatest risk because the alveolar bone is thin and can be easily damaged during extraction • Loss of ridge height or width can reduce the bone available to support dental implants

3. Normal post-extraction healing sequence • The socket fills with a blood clot • Oral epithelium migrates down the socket wall until it encounters granulation tissue • Oral epithelium migrates across the bed of granulation tissue until it encounters epithelium migrating from the opposite side of the socket. • Granulation tissue supports new bone formation

4. Technique for ridge preservation • Sever the periodontal ligament and extract the failing tooth with minimal trauma, preserving the socket walls • Remove all soft tissue from the socket and encourage bleeding from the socket walls • Fill the socket with a hard tissue graft material • Place a barrier membrane, replace the flap and secure the site with mattress sutures

5. Infected extraction sites • If the socket is infected and an exudate is present at the time of extraction, guided bone regeneration should be postponed until after initial healing and resolution of the infection

21. Randomized clinical studies of ridge preservation outcomes • Iasella et al (2003) studied 24 subjects requiring a non-molar extraction • Half were randomly selected for extraction alone (controls) • Half were selected for ridge preservation using FDBA and a collagen membrane • Ridge dimensions were measured after 6 months

22. Iassella et al (2003) findings

23. Iassella et al (2003) findings • Extraction alone sites lost 1.6 mm more width on average • Extraction alone sites lost ridge height, while ridge preservation sites gained (for a height difference of 2.2 mm). • Extraction alone sites exhibited less bone fill

24. Vance et al (2004) • This study compared ridge dimensions and bone fill after socket grafting with two different graft materials: • bone allograft in a putty carrier with a calcium sulfate barrier (PUT group) • bovine bone xenograft with a collagen membrane (BDX group). • The treatment choice was randomly selected in 24 subjects requiring a non-molar extraction. • Outcomes were evaluated 4 months after surgery.

25. Vance et al (2004) findings • Average ridge width decreased by 0.5 mm in both groups • The PUT group lost 0.5 mm of vertical ridge height, while the BDX group gained 0.7 mm • The PUT group exhibited a significantly higher degree of bone fill in the socket

26. Summary • Ridge preservation surgery provides a means for more predictable maintenance of ridge width and height after extraction. • If a patient’s treatment plan involves replacing a failing tooth with an implant, consideration should be given to ridge preservation at the time of extraction.

27. Diagnosis and Treatment of Peri-implantitis Dent 664

28. Which factors most often contribute to failure of osseointegrated implants that were previously stable and functional? • Excessive loading • Infection

29. Peri-implant mucositis and peri-implantitis • Peri-implant mucositis • Inflammation of peri-implant soft tissues • Reversible • Peri-implantitis • Inflammatory process around implants • Involves loss of peri-implant bone

30. Diagnosis of peri-implant infections is based on the following findings: • Bleeding on probing (BOP) around the implant • Suppuration around the implant • Probing depth around the implant • Mobility of the implant • Radiographic evidence of bone loss around the implant

31. Peri-implant mucositis • Clinical Features • similar to gingivitis in natural teeth • signs of inflammation like redness, swelling • Bleeding on probing good indicator

32. Peri-implant mucositis • The gingiva around teeth and the mucosa around implants exhibit responses to plaque that are somewhat similar • However, histological studies suggest that peri-implant mucosa is less capable of containing and repairing the damage caused by plaque-induced inflammation

33. Peri-implantitis • Clinical Features • inflammation of peri-implant mucosa (BOP, redness) • peri-implant bone loss

34. Peri-implantitis: histology • Experimental periodontitis and peri-implantitis have been compared in dogs • plaque associated with both sites is similar • inflammatory lesion associated with peri-implantitis tends to extend to involve the bone. In contrast, there is typically a zone of non-inflamed connective tissue interposed between the inflammatory lesion and the bone in periodontitis

35. Peri-implantitis histology (continued) • Human peri-implantitis lesions are characterized by the presence of numerous neutrophils in the tissue surrounding the implant and direct contact between plaque on the implant surface and inflamed connective tissue. • These features are not seen in periodontitis

37. Criteria for a successful implant (Albrektsson et al, 1986) • The implant is immobile • Absence of peri-implant radiolucency • Absence of pain, infection, neuropathy or paresthesia • After 1st year in function, < 0.2 mm vertical bone loss anually

38. When things go wrong: Definitions • Failing implant: • progressive alveolar bone loss, pocket formation, bleeding on probing, or suppuration • Failed implant: • hopeless and nonfunctional implant requiring removal • may exhibit loss of osseointegration, mobility, or pain

39. Treatment of failing implants • Resolution of inflammation • debridement of plaque • improvement of oral hygiene • use of adjunctive antibiotics • Correction of unfavorable soft tissue morphology (pseudopockets) by flap surgery or gingivectomy • Re-osseointegration - decontaminate implant surface with citric acid or tetracycline solutions, guided bone regeneration

40. Treatment of failed implants • Remove the implant • Implant removal, followed by guided bone regeneration and subsequent placement of a replacement implant • Remove the implant from function, decontaminate it and submerge it

41. Case 1 Removal of a failed implant

45. Case 2: Bone graft around a failing implant