Written by Steven L. Rasner, DMD Wednesday, 30 September 2009 19:00
A longstanding challenge to the restorative dentist is single-tooth replacement in an atrophic ridge crest. The loss of bone volume after tooth loss has received considerable attention in the literature. Different rates and patterns of alveolar loss have been observed, depending on where and how the tooth was lost. A 25% decrease in facial palatal width occurs in the first 12 months, and can be as great as 40% within 3 years.1 This article will present a predictable method for replacing the lost bone prior to implant placement through the ramus block graft technique.
Diagnosis and Treatment Planning
Figure 1. Preoperative smile. Tooth No. 6 missing.
|Figure 2. Buccal palatal deficiency.|
A 42-year-old female presented to our office in March 2006. She expressed a desire to discuss alternatives for tooth replacement of her missing right maxillary cuspid (Figure 1). The patient had worn a maxillary removable partial denture for 26 years. A comprehensive oral exam, panoramic radiograph, bite-wings, and models mounted in the centric relation position were done. The patient‘s medical history had no contraindications to treatment, and her dental exam was unremarkable. Tooth No. 6 had been lost at age 16 years due to extensive caries. Although conventional crown and bridge was discussed as a treatment option, it was discouraged because of: (1) the lack of any restorations on the potential abutment teeth Nos. 5 and 7, and (2) the unfavorable morphology of tooth No. 7 as an abutment in a 3-unit bridge.
A root form implant with prior bone augmentation was the recommended treatment. Specifically, an autogenous block graft from the ramus buccal shelf was the suggested donor site. It is common in the maxillary incisor region to have significant bone width compromise due to the thinness of the overlying labial plate (Figure 2).1 The utilization of the ramus area as opposed to the mandibular symphysis is dictated by clinical access and anatomy.2 Although the position of the inferior alveolar canal, the external oblique ridge, and anterior posterior dimensions of the ramus can be evaluated with a panoramic radiograph, it is noteworthy that many studies show it to be the least accurate, with distortions ranging from 3.0 to 7.0 mm.3 Cone beam computed tomography (CT scanning) exhibits uninterrupted continuity with the least distortion, ranging from 0.2 mm to 0.5 mm. As such, the anterior posterior width of the ramus can best be evaluated with a CT analysis.2
The range of harvestable bone from the ramus is a rectangular piece 3 to 4 mm in thickness, 1 to 3.5 cm in length, and usually about 1.0 cm in height.4 The preoperative clinical evaluation indicated a desired graft of approximately 3.0 mm, in thickness, 8 mm in height, and 12 mm in length.
SURGERY: PHASE I
The preoperative medications were as follows: premedication (oral sedation) using Triazolam 0.25 mg, Atarax 50 mg, and Benadryl 25 mg, all taken 90 minutes prior to appointment. Amoxicillin 500 mg, Ibuprofen 600 mg Dexamethosone 9.0 mg- Vicodin ESprn. Chlorhexidine Gluconate 0.12% oral rinse (Peridex [OMNI Preventive Care, a 3M ESPE Company]) was also prescribed. (Rinse with one capful for 30 seconds twice a day starting day after surgery.) Vitals were taken and recorded every 10 minutes with a pulse oximeter.
The Recipient Site
The recipient site was anesthetized with local infiltration using 1.8 ml 2% lidocaine, along with palatal anesthesia. The donor site was anesthetized with an inferior alveolar nerve block using the same anesthesia along with 1.0 m of 0.5% Marcaine (1:200,000 epinephrine) (Cook-Waite Novocol Pharmaceuticals of Canada). In the recipient area, a sulcular incision, with 2 vertical releasing incisions on the distal aspect of teeth Nos. 4 and 7, was made. On the underlying bone, a rectangular shape is subtly outlined with No. 6 (Brasseler USA) diamond round bur, and the entire area to receive the block was decorticated approximated 1.0 mm in depth. The decortication sets up a regional acceleratory phenomenon. This involves platelet release from damaged blood vessels, increased osteogenesis, cell availability and overall a better graft union to the host bone.5
The Donor Site
A distal oblique releasing incision was made at the buccinator muscle, at the distal aspect of the retromolar pad. Sucular incisions both buccal and lingual were made up to the mandibular cuspid with a vertical releasing incision mesial to the cuspid. A full-thickness mucoperiosteal flap was made allowing direct view of buccal the shelf and the mental neurovascular bundle.
|Figure 3. Preoperative donor site.
||Figure 4. Buccal shelf exposed.
Figure 5. Harvest outline.
In this procedure, 3 basic bone cuts were utilized. First the superior osteotomy was made with a 702 L (Brasseler USA) bur. This was made 4.0 mm medial to the buccal shelf, and continued anteriorly up to the first molar site as needed. In this case, we stopped at about 1.4 cm. Then, a vertical cut that flared out wider at the inferior portion of the graft was made with the 702 L. (Figures 3 to 5).
|Figure 6. Outfracture with Tatum bone spreader (Sun Coast Dental).
||Figure 7. Platelet rich plasma (PRP).
Figure 8. PRP in donor area.
Finally, the inferior osteotomy was made with a No. 8 (Brasseler USA) round bur. This was more of a “scoring” than a cut, and the graft was out-fractured from the superior portion with a Tatum bone spreader (Sun Coast Dental) (Figure 6). It is not necessary to place anything in the remaining defect, although a membrane of rich plasma protein was used in this case. Much has been written about the use of platelet rich plasma (PRP) and other growth factors in conjunction with autogenous bone grafts. The patient’s blood is drawn, centrifuged and fractionated into 3 components by gradient dentistry (Harvest Technolo-gies) (Figures 7 and 8).6
The platelet concentration obtained is one million platelets/wl versus the normal average of 200,000 platelets/wl. By itself, PRP cannot induce bone formation. However, it can be used as a “spark” that ignites a process that ultimately enhances bone maturation as well as soft-tissue closure.7
|Figure 9. Harvested ramus graft.
||Figure 10. Two-point screw fixation.
Figure 11. Mineross (BioHorizons)and PRP around block graft.
The graft is then contoured and placed in the recipient site. The block is fixated with 2-point screw fixation (Osteomed screws [Osteomed Corp]) 1.6 x 10 mm length (Figures 9 and 10). Any voids around the periphery of the graft are filled with a combination of 0.5 cc of Mineross (BioHorizons) with rich plasma protein (Figure 11). Both areas are sutured tension-free, utilizing 4.0 and 3.0 Vicryl suture (Ethicon [Johnson & Johnson]). The patients existing partial denture was then relined and utilized as the provisional on the day of surgery.
Typically, intraoral block grafts are allowed to heal for a minimum of 4 months for maxillary sites.8 The higher vascular maxillary cortex allows for a more rapid angiogenesis of the graft then in mandibular sites.9
SURGERY PHASE II: IMPLANT PLACEMENT
|Figure 12. Postoperative photo (5 months) of ramus graft.
||Figure 13. Implant placement.
|Figure 14. Roll graft for “plumping.”
||Figure 15. Roll graft sutured.
|Figure 16. Postoperative photo (8 weeks) of roll graft.
||Figure 17. Implant at 3 months.
|Figure 18. Zirconium oxide abutment.
||Figure 19. Zirconium oxide abutment in place.
Figure 20. Final restoration (Lava [3M ESPE] crown).
At 5 months from the first surgery, the patient returned for implant placement. The same pre-op medication and anesthesia protocol for the maxillary recipient site were utilized. The incision line from the first surgery was followed. The graft had become fully fixated, and the 2 Osteomed screws were removed (Figures 12 and 13).
The goals of ideal anterior implant placement include the following:
The center of the implant should be located directly under the incisal edge of the crown. This portion improves the angle of force to the implant, and lends itself to excellent aesthetics.10
Furthermore, we would strive to position the top of the implant platform 2.0 mm below the adjacent facial cementoenamel junction. This will provide 3.0 mm of soft-tissue drape in a healthy periodontium leading to ideal aesthetics.11
Both of these goals were easily accomplished since the ramus graft yielded abundant bone in our recipient site. Ramus grafts exhibit minimal resorption rates at 0 to 20%.12 A 4.3 x 12 mm Replace Select (Nobel Biocare) implant was utilized. A healing cap was placed, and closure was achieved using 4.0 vicryl sutures. The patient continued to wear the original maxillary partial denture (further relined for the healing cap). At this point in the uncovery, it was decided that the aesthetic outcome of the final restoration would be enhanced if we “plumped out” the overlying tissue. A de-epithelialized connective tissue pedicle graft was utilized. There is abundant attention to this procedure in the literature (Figures 14 to 16).13
Final impressions were taken at 12 weeks post-op (Figure 17). A direct implant impression protocol was followed. The dental laboratory prescription called for the custom fabrication of a zirconium abutment with a Lava (3M ESPE) all-ceramic crown. The final restoration was cemented 8 months after the original office visit to the patient’s satisfaction (Figures 18 to 20).
This article has demonstrated a predictable and aesthetic method for replacing the lost bone prior to implant placement through the ramus block graft technique.
The author would like to thank Steve Headquest, CDT, of Valley Dental Arts, Stillwater, Minn, for his excellent laboratory work.
- Misch CE. Single tooth replacement: surgical considerations. In: Contemporary Implant Dentistry. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2007:742.
- Misch CE. Mandibular donor block bone grafts: symphysis and ramus. In: Contemporary Implant Dentistry. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2007:991.
- Rosenfeld AL, Mecall RA. The use of interactive computed tomography to predict the esthetic and functional demands of implant-supported prostheses. Compend Contin Educ Dent. 1996:17:1125-1128.
- Misch CE. Use of the mandibular ramus as a donor site for onlay bone grafting. J Oral Implantol. 2000;26:42-49.
- Frost HM. The regional acceleratory phenomenon: a review. Henry Ford Hosp Med J. 1983;31:3-9.
- Zinner ID, Panno FV, Small SA, et al (eds). Implant Dentistry: From Failure to Success. Hanover Park, Ill: Quintessence Publishing Co; 2004:54.
- Misch CE. Keys to bone grafting materials: socket grafting. In: Contemporary Implant Dentistry. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2007:850.
- Pikos MA. Alveolar ridge augmentation with ramus buccal shelf autografts and impacted third molar removal. Dent Implantol Update. 1999;10:28.
- Misch CE. Mandibular donor block bone grafts: symphysis and ramus. In: Contemporary Implant Dentistry. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2007:1007.
- Misch CE. Single tooth replacement: surgical considerations. In: Contemporary Implant Dentistry. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2007:747.
- Misch CE. Single tooth replacement: surgical considerations. In: Contemporary Implant Dentistry. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2007:749-750.
- Sato N. Increasing the attached gingiva. In: Periodontal Surgery: A Clinical Atlas. Carol Stream, Ill: Quintessence Publishing Co; 2000:91-107.
- Langer B, Calagna L. The subepithelial connective tissue graft. J Prosthet Dent. 1980;44:363.
Dr. Rasner is a general practitioner from Bridgeton, NJ. In 1998 he founded Realizing the Dream, a collection of professional practice tools including speaker services, books, in-office training tapes, videos, and practice management products. He can be reached at (800) 337-8435.
Disclosure: Dr. Rasner reports no conflicts of interest.
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