Ridge Widening and Immediate Implant Placement
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By JDI editor
Published on 02/10/2001
Tetsuo Shimoyama, DDS, PhD, Takahiro Kaneko, DDS, Shinjirou Shimizu, DDS, Daigo Kasai, DDS, Takahiro Tojo, DDS, Norio Horie, DDS, PhD
Department of Oral and Maxillofacial Surgery, Saitama Medical Center, Medical School, Saitama, Japan.
Alveolar atrophy may present an anatomical limitation to the placement of endosseous implants. A case is described of severe maxillary alveolar atrophy with immediate implant placement associated with a ridge widening technique in accordance with a split-crest-bone manipulation. Taper-shaped implants were applied in this technique without a barrier membrane. Because this implant was small and tapped into position, it was easier to use and was considered to be appropriate for the ridge widening technique associated with immediate implant placement.
Department of Oral and Maxillofacial Surgery, Saitama Medical Center, Medical School, Saitama, Japan.
Alveolar atrophy may present an anatomical limitation to the placement of endosseous implants. A case is described of severe maxillary alveolar atrophy with immediate implant placement associated with a ridge widening technique in accordance with a split-crest-bone manipulation. Taper-shaped implants were applied in this technique without a barrier membrane. Because this implant was small and tapped into position, it was easier to use and was considered to be appropriate for the ridge widening technique associated with immediate implant placement.
A Case Report
Tetsuo Shimoyama, DDS, PhD, Takahiro Kaneko, DDS, Shinjirou Shimizu, DDS, Daigo Kasai, DDS, Takahiro Tojo, DDS, Norio Horie, DDS, PhD
Department of Oral and Maxillofacial Surgery, Saitama Medical Center, Medical School, Saitama, Japan.
Alveolar atrophy is a major problem that has limited the use of endosseous implants since their introduction. When an anterior tooth in the maxilla is lost, often as a result of trauma or endodontic complications, the labial wall of the alveolar socket resorbs rapidly and the residual ridge actually consists of the previous palatal wall. Therefore, the alveolar ridge is predominantly reduced in the horizontal dimension, and immediate implant placement with routine techniques is not possible because of the discrepancy between the thickness of the ridge and the diameter of the implant. Although numerous procedures have been devised to augment the alveolar crest with autogenous bone grafting, such as the ribs and iliac crest, sometimes in conjunction with a barrier membrane, a risk of dehiscence and infections of the mucosa may jeopardize the graft. Furthermore, a two-stage approach to implant placement is generally advocated, lengthening treatment time and increasing cost. In 1992, Simion et al introduced a split-crest-bone manipulation technique. The purpose of this technique was to create self-spacemaking defects by splitting the atrophic crests into two parts with a longitudinal greenstick fracture and placing the implant between them, which is also an effective technique for severely thin alveolar bone. This is advocated when a standard osteotomy technique in which a crest width .4 mm is recommended cannot be applied. Various types of implants have been used within the ridge widening procedure. Because the taper-shaped implants (Endopore implant system, Innova, Toronto, ON) are tapped into position similarly to the driving of a wedge, it is considered to be appropriate for this procedure. The present study reports a case of severe maxillary alveolar atrophy during placement of an immediate taper-shaped implant associated with a ridge widening procedure (RWP) in accordance with Simion et al.
MATERIALS AND METHODS.
57-year-old woman was referred for prosthetic treatment associated with implant placement. Clinical examination showed an edentulous margin with obvious labial and buccal bone resorption (Lekholm and Zarb’s class D atrophy). The radiographic appearance indicated an adequate bone height for implant placement, except that the tomogram view of the anterior maxilla region revealed a knife-edge morphology. For the purpose of placing the implant with an overdenture abutment that assists denture support, two Endopore (Innova) implant placements in the bilateral premolar regions were scheduled.
Surgical Procedure.
For the prosthetic treatment associated with the implant placement, an Endopore (Innova) implant system was prepared.
After appropriate sedation (diazepam, 5 mg; intravenous injection), an incision was made on the crest of the ridge of the bilateral premolar regions slightly toward the palate. In addition, mesial and distal vertical incisions were extended in the buccal direction for the purpose of flap relief. Using a periosteal elevator, mucoperiosteal flaps were buccally elevated sufficient to visualize the alveolar ridge anatomy. After this, the bone crests revealed that the ridge width was approximately 2 mm in diameter and the buccal aspect had a concave form. A surgi chisel was carefully tapped with a mallet to create a channel along the crest of the bone. The channels were extended to a depth of 8 to 10 mm to reduce the occurrence of cortical plate fracture in the subsequent procedures. After cortical plate separation, the punch tip (Endopore [Innova] implant system) was used, starting with the punch tip starter. Using a rotating motion of the two-sized punch tip pilots, the cortical plates were further widened to approximately 4 mm. The final depth and orientation of the prepared sites were then checked by inserting the appropriate trial-fit gauge. After saline irrigation, the Endopore (Innova) implant fixtures (length, 7 mm; diameter, 4.1 mm) were placed and driven into their final fully seated positions with several firm taps using a Teflon-tipped punch and mallet. Releasing incisions in the periosteum at the base of the flap were made to enhance the elasticity of the flap. Closure was carried out by using vertical mattress sutures.
Stage II surgery was scheduled six months after the implantation. Complete healing of the defects had taken place, and the fixtures were covered by regenerated bone. After the soft tissue was restored by placement of a healing abutment, an overdenture abutment was attached to the implant fixture. For the final prosthesis, the overdenture was seated and no functional disorders were observed during five months of follow-up.
Department of Oral and Maxillofacial Surgery, Saitama Medical Center, Medical School, Saitama, Japan.
Alveolar atrophy is a major problem that has limited the use of endosseous implants since their introduction. When an anterior tooth in the maxilla is lost, often as a result of trauma or endodontic complications, the labial wall of the alveolar socket resorbs rapidly and the residual ridge actually consists of the previous palatal wall. Therefore, the alveolar ridge is predominantly reduced in the horizontal dimension, and immediate implant placement with routine techniques is not possible because of the discrepancy between the thickness of the ridge and the diameter of the implant. Although numerous procedures have been devised to augment the alveolar crest with autogenous bone grafting, such as the ribs and iliac crest, sometimes in conjunction with a barrier membrane, a risk of dehiscence and infections of the mucosa may jeopardize the graft. Furthermore, a two-stage approach to implant placement is generally advocated, lengthening treatment time and increasing cost. In 1992, Simion et al introduced a split-crest-bone manipulation technique. The purpose of this technique was to create self-spacemaking defects by splitting the atrophic crests into two parts with a longitudinal greenstick fracture and placing the implant between them, which is also an effective technique for severely thin alveolar bone. This is advocated when a standard osteotomy technique in which a crest width .4 mm is recommended cannot be applied. Various types of implants have been used within the ridge widening procedure. Because the taper-shaped implants (Endopore implant system, Innova, Toronto, ON) are tapped into position similarly to the driving of a wedge, it is considered to be appropriate for this procedure. The present study reports a case of severe maxillary alveolar atrophy during placement of an immediate taper-shaped implant associated with a ridge widening procedure (RWP) in accordance with Simion et al.
MATERIALS AND METHODS.
57-year-old woman was referred for prosthetic treatment associated with implant placement. Clinical examination showed an edentulous margin with obvious labial and buccal bone resorption (Lekholm and Zarb’s class D atrophy). The radiographic appearance indicated an adequate bone height for implant placement, except that the tomogram view of the anterior maxilla region revealed a knife-edge morphology. For the purpose of placing the implant with an overdenture abutment that assists denture support, two Endopore (Innova) implant placements in the bilateral premolar regions were scheduled.
Surgical Procedure.
For the prosthetic treatment associated with the implant placement, an Endopore (Innova) implant system was prepared.
After appropriate sedation (diazepam, 5 mg; intravenous injection), an incision was made on the crest of the ridge of the bilateral premolar regions slightly toward the palate. In addition, mesial and distal vertical incisions were extended in the buccal direction for the purpose of flap relief. Using a periosteal elevator, mucoperiosteal flaps were buccally elevated sufficient to visualize the alveolar ridge anatomy. After this, the bone crests revealed that the ridge width was approximately 2 mm in diameter and the buccal aspect had a concave form. A surgi chisel was carefully tapped with a mallet to create a channel along the crest of the bone. The channels were extended to a depth of 8 to 10 mm to reduce the occurrence of cortical plate fracture in the subsequent procedures. After cortical plate separation, the punch tip (Endopore [Innova] implant system) was used, starting with the punch tip starter. Using a rotating motion of the two-sized punch tip pilots, the cortical plates were further widened to approximately 4 mm. The final depth and orientation of the prepared sites were then checked by inserting the appropriate trial-fit gauge. After saline irrigation, the Endopore (Innova) implant fixtures (length, 7 mm; diameter, 4.1 mm) were placed and driven into their final fully seated positions with several firm taps using a Teflon-tipped punch and mallet. Releasing incisions in the periosteum at the base of the flap were made to enhance the elasticity of the flap. Closure was carried out by using vertical mattress sutures.
Stage II surgery was scheduled six months after the implantation. Complete healing of the defects had taken place, and the fixtures were covered by regenerated bone. After the soft tissue was restored by placement of a healing abutment, an overdenture abutment was attached to the implant fixture. For the final prosthesis, the overdenture was seated and no functional disorders were observed during five months of follow-up.
Discussion - References.
DISCUSSION.
Alveolar atrophy may present an anatomical limitation to the placement of endosseous implants. Many osseous augmentation techniques, including bone grafting, use of membranes for guided tissue regeneration,8–10 and RWP, have been used in the treatment of this problem. In these treatments, most techniques described placing implants with sufficient bone height (.10 mm) but insufficient width (,4 mm). The following are the benefits of the RWP compared with other methods:
Most RWPs associated with immediate implant placement have used expanded polytetrafluoroethylene membranes or polyglactin 910 mesh for guided tissue regeneration. Although the possible benefits of guided tissue regeneration have received considerable attention in previous studies, the use of a membrane always increases the risk of complications, such as infections, painful inflamed tissues, and disrupted wound healing. In addition, various studies have reported complication rates of 20% to 50% when using membranes. In RWPs associated with immediate implant placement, the primary wound closure is generally more difficult compared with that of a standard implant placement and the risk of membrane exposure increases because the natural crest is dramatically augmented. For these reasons, we treated five atrophy cases, including the present one, without the membrane technique. Subsequent wound healing and osseointegration of the implants were uneventful. Furthermore, the reason for successful regeneration surrounding the implant without the membrane technique may be attributed to the small size and tapered shape of the implant, which is a beneficial shape to gradually widen a split crest. Only a small percentage of fusiform defects are made by the splitting process. In a small percentage of defect cases, the membrane is not essential for bone regeneration.
In their study of RWPs, Duncan et al described a higher success rate with a cylinder implant compared with a screw implant because the cylinder type was tapped into position and was easier to use. The Endopore (Innova) implant system also uses a tapping method when placed into bone. In addition, its tapered implant shape is believed to be a factor for an increased success rate. These factors suggest that the Endopore (Innova) implant system may be more appropriate for ridge widening procedures associated with immediate implantation.
REFERENCES.
Alveolar atrophy may present an anatomical limitation to the placement of endosseous implants. Many osseous augmentation techniques, including bone grafting, use of membranes for guided tissue regeneration,8–10 and RWP, have been used in the treatment of this problem. In these treatments, most techniques described placing implants with sufficient bone height (.10 mm) but insufficient width (,4 mm). The following are the benefits of the RWP compared with other methods:
- the RWP allows the implant to be placed in a less invasive manner and avoids donor-site morbidity caused by bone grafting;
- the RWP allows primary implant placement and significantly shortens the treatment time;
- the RWP allows treatment of narrow ridge location within the context of a routine dental office procedure.
Most RWPs associated with immediate implant placement have used expanded polytetrafluoroethylene membranes or polyglactin 910 mesh for guided tissue regeneration. Although the possible benefits of guided tissue regeneration have received considerable attention in previous studies, the use of a membrane always increases the risk of complications, such as infections, painful inflamed tissues, and disrupted wound healing. In addition, various studies have reported complication rates of 20% to 50% when using membranes. In RWPs associated with immediate implant placement, the primary wound closure is generally more difficult compared with that of a standard implant placement and the risk of membrane exposure increases because the natural crest is dramatically augmented. For these reasons, we treated five atrophy cases, including the present one, without the membrane technique. Subsequent wound healing and osseointegration of the implants were uneventful. Furthermore, the reason for successful regeneration surrounding the implant without the membrane technique may be attributed to the small size and tapered shape of the implant, which is a beneficial shape to gradually widen a split crest. Only a small percentage of fusiform defects are made by the splitting process. In a small percentage of defect cases, the membrane is not essential for bone regeneration.
In their study of RWPs, Duncan et al described a higher success rate with a cylinder implant compared with a screw implant because the cylinder type was tapped into position and was easier to use. The Endopore (Innova) implant system also uses a tapping method when placed into bone. In addition, its tapered implant shape is believed to be a factor for an increased success rate. These factors suggest that the Endopore (Innova) implant system may be more appropriate for ridge widening procedures associated with immediate implantation.
REFERENCES.
- Jensen J, Sindet-Pedersen S, Oliver AJ. Varying treatment strategies for reconstruction of maxillary atrophy with implant: Results in 98 patients. J Oral Maxillofac Surg. 1994;52:210–216.
- De wiji FLJA, Cune MS. Immediate labial contour restoration for improved esthetic: A radiographic study on bone splitting in anterior single-tooth replacement. Int J Oral Maxillofac Implant. 1997; 12:686–696.
- Misch CM, Misch CE. The repair of localized severe ridge defects for implant placement using mandibular bone grafts. Implant Dent. 1995;4:261–267.
- Sindet-Pedersen S, Enemark H. Reconstruction of alveolar clefts with mandibular or iliac crest bone grafts: A comparative study. J Oral Maxillofac Surg. 1990;48:554–558.
- Simion M, Baldoni M, Zaffe D. Jawbone enlargement using immediate implant placement associated with a splitcrest technique and guided tissue regeneration. Int J Periodontics Restorative Dent. 1992;12:462–473.
- Summers R. The ridge expansion osteotomy (REO). Compend Contin Educ Dent. 1994;15:422–436.
- Duncan JM, Westwood M. Ridge widening for the thin maxilla: A clinical report. Int J Oral Maxillofac Implants. 1997;12:224–227.
- Schultz AJ, Gaper AH. Guided tissue regeneration using absorbable membrane (polyglactin 910) and osseous grafting. Int J Periodontics Restorative Dent. 1990;10:9–17.
- Nyman S. Bone regeneration using the principle of guided tissue regeneration. J Clin Periodontol. 1991;18:494– 498.
- Nevins M, Mellonig JT. Enhancement of the damaged edentulous ridge to receive dental implants: A combination of allograft and GORE-TEX membrane. Int J Periodontics Restorative Dent. 1992;12: 97–111.
- Rominger JW, Triplett RG. The use of guided bone regeneration to improve implant osseointegration. J Oral Maxillofac Surg. 1994;52:106–113.
- Gotfredsen K, Nimb L, Buser D, et al. Evaluation of guided bone regeneration’s around implants placed into fresh extraction sockets: An experimental study in dogs. J Oral Maxillofac Surg. 1993;51: 879–886.
- Gotfredsen K, Warrer K, Hortin- Hansen E, et al. Effect of membranes and porous hydroxyapatite on healing in bone defects around titanium dental implants. Clin Oral Implants Res. 1991;2:172–178.
- Warrer K, Gotfredsen K, Hortin- Hansen E, et al. Guided tissue regeneration ensures osseointegration of dental implants placed into extraction sockets. Clin Oral Implants Res. 1991;2:166–171.
- Becker W, Becker B, Handelsman M, et al. Guided bone regeneration for implants placed into extraction sockets: A study in dogs. J Periodontol. 1991;62: 703–709.