Clinical Pearls for Surgical Implant Dentistry: Part 4



Figures 1a to 1d. Soft-tissue correction of recession on an implant. (a). Initial appearance with recession. (b). Connective tissue graft used to submerge the cover screw. (c). Primary closure. (d). Healed ridge.

In part 3 of this 4-part series of articles, clinical pearls related to adjunctive implant procedures were discussed. In part 4, there are 2 sections. The first is entitled “Handling Post Operative Problems.” The following subjects are addressed: soft-tissue dehiscence and correcting recession on the buccal aspect of an implant. In the second section, entitled “Important Numbers to Know,” clinically relevant numerical values pertaining to various procedures are reviewed.

HANDLING POSTOPERATIVE PROBLEMS
Soft-Tissue Dehiscence
The most common causes of wound dehiscences are trauma from inadequately relieved dentures, antagonistic teeth, or too much tension on the flap.¹ Therefore, after surgery, dentures should be relieved, possibly relined with a soft denture liner,² and the opposing dentition should be equilibrated as necessary to avoid trauma to an incision line. In addition, flaps must be coapted so that they are passive (tension free). There are 2 approaches to management of a soft-tissue dehiscence: resuturing or oral rinses. If the dehiscence is small and occurred within 24 to 48 hours, immediately resuture the dehiscence.² If the patient has traumatized wound margins, or it is in the anterior part of the mouth, or if a resorbable membrane was used, then employ chlorhexidine rinses 3 times a day, systemic antibiotics, and possibly local drug delivery weekly. The wound should be monitored weekly for 3 to 6 weeks until it heals by secondary intention. If a nonresorbable barrier becomes dehisced (eg, Gore-Tex), the same is done as above. However, if the margins of the barrier become exposed, then it is removed, because usually by the fourth week the nonresorbable barrier is contaminated.³ It typically takes 4 to 6 months for lamellar bone to form; thus if the barrier is removed after 4 weeks, it should be anticipated that the result will be compromised if initially there was a dehisced bony plate.

Correcting Recession on the Buccal Aspect of an Implant
Recession subsequent to implant placement in the maxillary anterior region is a dilemma. It is difficult to cover an exposed area of an implant. Coronally positioned flaps often recede back to their original position. Similarly, subepithelial connective tissue grafts placed on the buccal aspect may recede. One technique which may be of value to correct this problem consists of removing the crown and the abutment, inserting a cover screw, and then placing a connective tissue graft from buccal to lingual resubmerging the implant (Figures 1a to 1d). In other words, the status of the site is changed back to what occurred after stage one surgery. After the tissue heals, a stage 2 procedure (uncovering) can be done. If threads of the implant surface are exposed, the situation is more difficult to correct. The above can be performed and, after the soft tissue healing, a bone graft and a barrier is placed. Depending on the extent of the bone loss and the angle of the implant, it may be necessary to remove the implant and perform reconstructive procedures prior to continuing. In some cases, a different treatment plan may be needed.
The main reason for buccal recession is that the implant was placed too far buccally. If this diagnosis can be made, it may be better to remove the implant immediately, rebuild the bone, and eventually place a new implant; instead of trying to do multiple grafts and still having to remove the implant.

IMPORTANT NUMBERS TO KNOW
There are certain measurements that have been established in the literature that are useful and should be committed to memory.

• After tooth extraction, the average amount of alveolar bone loss on the buccal (width) within one year can be 4 mm,^4,5 or as much as 6.1 mm.⁶ This of course can vary depending on the site or the patient. More than 50% of this bone loss occurs during the first 3 months after extraction.⁶
• Biologic width is 1.5 to 2 mm. It is supracrestal around teeth, and can be subcrestal or supracrestal around implants.^7,8 This will depend on where the collar of the implant was placed. Minimum distance between an implant and a tooth should be 1.5 to 2 mm.^9,10
• Lateral biologic width around an implant is around 1.3 mm.¹¹ Violation of this width results in bone loss on the implant and adjacent structures.¹⁰
• Minimum distance between 2 implants should be 3 mm to maintain interproximal bone height.¹¹ Otherwise, there is increased bone loss. Distance between the bone crest and the cemento-enamel junction averages around 1.5 to 2 mm for teeth, but variations exist and bone sounding should be performed before therapeutic decisions are made.¹²
• Ideally, the platform of the implant should be 3 mm below the facial zenith of the soft tissue in the aesthetic zone.¹³
• Natural scallop of bone between midfacial and interproximal bone of maxillary anterior teeth varies from 2.1 to 4.1 mm (average 3 mm).¹⁴
• Vertical height needed between the platform of an implant and the opposing dentition is approximately 7 mm; less interarch space calls for the utilization of UCLA-type screw down components (about 4 mm clearance needed).¹⁵
• Mesiodistal distance needed for a standard implant (4 mm diameter) is around 7 mm.
• Jumping distance is the distance between and immediate implant and the adjacent bone. It was once believed that if this distance was greater than 1.5 mm, a bone graft was needed; however, this is controversial and many clinicians believe that larger gap fills with bone.^16,17
• Native bone below the sinus is around 25% bone and 75% marrow. After a sinus lift, the regenerated bone is around 25% vital bone, 25%, graft material and 50% marrow.¹⁸ The regenerated bone usually does not have a higher percentage of vital bone than the adjacent bone.¹⁹
• After an extraction, even if all bony walls are present, do socket preservation, if the buccal plate is 1.0 mm thick; do not do it if the buccal plate is 2 mm thick. As bone thickness approaches 1.8 to 2 mm, there is little bone loss.²⁰
• The length of a No. 15 surgical blade is 10 mm. This is a useful guide when acquiring a subepithelial connective tissue graft.
• The bevel on a No. 15 blade is 1.0 mm wide; this is useful guide when measuring thickness for garnering a free gingival graft from the palate.

CLOSING COMMENTS
Numerous subjects were addressed in this clinical commentary. The material presented is an attempt to share many clinical pearls presented by colleagues and mentors. Their suggestions may facilitate therapy, help avoid problems, and could aid in managing complications. Some of the techniques presented are the creation of specific clinicians. Remember these axioms passed down by many talented mentors: always follow sound biologic principles; keep the treatment plan simple if possible; do one small miracle at a time; think restoratively; be prepared to improvise; share your knowledge with others; maintain a standard of excellence; and finally, treat patients the way you would like to be treated.

References

1. Esposito M, Hirsch J, Lekholm U, et al. Differential diagnosis and treatment strategies for biologic complications and failing oral implants: a review of the literature. Int J Oral Maxillofac Implants. 1999;14:473-490.
2. Sadig W, Almas K. Risk factors and management of dehiscent wounds in implant dentistry. Implant Dent. 2004;13:140-147.
3. Simion M, Baldoni M, Rossi P, et al. A comparative study of the effectiveness of e-PTFE membranes with and without early exposure during the healing period. Int J Periodontics Restorative Dent. 1994;14:166-180.
4. Lekovic V, Kenney EB, Weinlaender M, et al. A bone regenerative approach to alveolar ridge maintenance following tooth extraction. Report of 10 cases. J Periodontol. 1997;68:563-570.
5. Covani U, Cornelini R, Barone A. Bucco-lingual bone remodeling around implants placed into immediate extraction sockets: a case series. J Periodontol. 2003;74:268-273.
6. Schropp L, Wenzel A, Kostopoulos L, et al. Bone healing and soft tissue contour changes following single-tooth extraction: a clinical and radiographic 12-month prospective study. Int J Periodontics Restorative Dent. 2003;23:313-323.
7. Cochran DL, Hermann JS, Schenk RK, et al. Biologic width around titanium implants. A histometric analysis of the implanto-gingival junction around unloaded and loaded nonsubmerged implants in the canine mandible. J Periodontol. 1997;68:186-198.
8. Hermann JS, Buser D, Schenk RK, et al. Biologic Width around one- and two-piece titanium implants. Clin Oral Implants Res. 2001;12:559-571.
9. Buser D, Martin W, Belser UC. Optimizing esthetics for implant restorations in the anterior maxilla: anatomic and surgical considerations. Int J Oral Maxillofac Implants. 2004;19(suppl):43-61.
10. Esposito M, Ekestubbe A, Gröndahl K. Radiological evaluation of marginal bone loss at tooth surfaces facing single Brånemark implants. Clin Oral Implants Res. 1993;4:151-157.
11. Tarnow DP, Cho SC, Wallace SS. The effect of inter-implant distance on the height of inter-implant bone crest. J Periodontol. 2000;71:546-549.
12. Kois JC. Predictable single-tooth peri-implant esthetics: five diagnostic keys. Compend Contin Educ Dent. 2004;25:895-896.
13. Saadoun AP, LeGall M, Touati B. Selection and ideal tridimensional implant position for soft tissue aesthetics. Pract Periodontics Aesthet Dent. 1999;11:1063-1072.
14. Becker W, Ochsenbein C, Tibbetts L, et al. Alveolar bone anatomic profiles as measured from dry skulls. Clinical ramifications. J Clin Periodontol. 1997;24:727-731.
15. Misch CE, Goodacre CJ, Finley JM, et al. Consensus conference panel report: crown-height space guidelines for implant dentistry—part 2. Implant
    Dent. 2006;15:113-121.
16. Botticelli D, Berglundh T, Buser D, et al. The jumping distance revisited: An experimental study in the dog. Clin Oral Implants Res. 2003;14:35-42.
17. Wang HL, Boyapati L. “PASS” principles for predictable bone regeneration. Implant Dent. 2006;15:8-17.
18. Froum SJ, Tarnow DP, Wallace SS, et al. The use of a mineralized allograft for sinus augmentation: an interim histological case report from a prospective clinical study. Compend Contin Educ Dent. 2005;26:259-268.
19. Valentini P, Abensur D, Densari D, et al. Histological evaluation of Bio-Oss in a 2-stage sinus floor elevation and implantation procedure. A human case report. Clin Oral Implants Res. 1998;9:59-64.
20. Spray JR, Black CG, Morris HF, et al. The influence of bone thickness on facial marginal bone response: stage 1 placement through stage 2 uncovering. Ann Periodontol. 2000;5:119-128.

Dr. Greenstein is clinical professor of dental medicine, Department of Periodontology, at Columbia University College of Dental Medicine. He is in private practice 4 days a week. Dr. Greenstein is a graduate of NYUCD (1972), received his periodontal training at the Eastman Dental Center (1980) and his MS from the University of Rochester in 1981. Dr. Greenstein is a board Diplomate of American Academy of Periodontolgy. He has authored over 100 articles on periodontal and implant therapy and has been the recipient of the following awards: Gies Award for contributions to the literature, American Academy of Periodontology; Hirschfeld Award—Northeast Society of Periodontology; Fellowship Award—American Academy of Periodontology. He can be reached at ggperio@aol.com.

Disclosure: Dr. Greenstein reports no disclosures.

Dr. Cavallaro is the clinical director of the implant fellowship progtram and an associate clinical professor in the Department of Prosthodontics at Columbia University College of Dental Medicine. Dr. Cavallaro teaches implant literature review as well as the surgical and prosthetic aspects of implant dentistry. He is a Member of the Academy of Osseointegration and a Fellow of the Greater New York Academy of Prosthodontics. Dr. Cavallaro maintains a full-time private practice of surgical implantology and prosthodontics in Brooklyn, NY. He has published multiple articles on surgical and prosthetic implant dentistry and has lectured on these subjects for the past 20 years. He can be reached via e-mail at docsamurai@rr.com.

Disclosure: Dr. Cavallaro reports no disclosures.

Dr. Tarnow is the director of dental implant education and clinical professor of dental medicine, Department of Periodontology at Columbia University College of Dental Medicine. Dr. Tarnow has a certificate in periodontics and prosthodontics and is a Diplomate of the American Board of Periodontology. He is a recipient of the Master Clinician Award from the American Academy of Periodontology and Teacher of the Year Award from New York University (NYU). Dr. Tarnow has a private practice in New York City, and has been honored with a wing named after him at NYU College of Dentistry. He has published more than 100 articles on perioprosthodontics and implant dentistry and has coauthored 3 textbooks including 2008 Aesthetic Restorative Dentistry. Dr. Tarnow has lectured extensively internationally in more than 30 countries. He can be reached at dennis.tarnow@gmail.edu.

Disclosure: Dr. Tarnow reports no disclosures.