Use of 6-mm Short Implants in Japanese Patients: Clinical, Radiologic, and Patient Satisfaction Results in a Retrospective Study with a 2-Year Follow-up.

Implant therapy for tooth loss in the molar area is challenging due to the anatomical limitations, requiring bone augmentation procedures that are associated with high surgical complexity and long postsurgical recovery. Recently, many studies have demonstrated the usefulness of short implants. However, few studies have been performed in Japanese patients to evaluate peri-implant bone changes, changes in peri-implant epithelial tissue, and patient satisfaction. The present study included 16 patients (5 men, 11 women; mean age: 60 years) who received 26 short (6-mm) implants. Changes in peri-implant bone and epithelial tissue were measured radiographically at superstructure loading and after 2 years. Peri-implant pocket probing depth was measured at the epithelial tissue and compared at both time points. Patient satisfaction was graded using the Oral Health Impact Profile (OHIP-14) before treatment and at follow-up. The mean mesial and distal bone levels were -0.05 mm and 0.37 mm at loading, respectively, and were 0.33 mm and 0.53 mm after 2 years, respectively. Significant peri-implant bone formation for mesial and distal bone levels at both time points were determined by Wilcoxon signed-rank test. Mean probing depth increased slightly, from 3.03 mm at loading to 3.33 mm after 2 years, but no significant difference was found. The OHIP-14 found that patient satisfaction levels increased after 2 years. Using 6-mm short implants in sites with insufficient bone levels can be a highly beneficial treatment option for patients, as it avoids the need for bone augmentation. However, more long-term and detailed studies on the clinical outcomes for these implants are required.

Nasopalatine duct cyst developed in association with dental implant treatment: A case report and histopathological observation.

Placement of an anterior maxillary implant has a risk of interfering with the nasopalatine canal in the maxilla. This case report presents one of our experiences of a nasopalatine duct cyst that developed in association with a dental implant treatment. A 45-year-old man received an implant in the maxillary left central incisor due to root fracture. Preoperative radiograph indicated no anatomical abnormalities. A postextraction immediate implant was placed, and radiographic examination after 28 months revealed an asymptomatic, oval-shaped radiolucency around the apex of the implant, seemingly in contact to the nasopalatine canal. The entire lesion was removed along with a part of the implant. Histopathologically it was diagnosed as nasopalatine duct cyst. Accidental contact with the nasopalatine canal during surgery may have induced development of the nasopalatine duct cyst. Careful planning based on preoperative computed tomography scan may prevent such complications.

Horizontal alveolar distraction osteogenesis for dental implant: long-term results.

OBJECTIVES: The aim of the present study was to present the results of patients followed for at least 3 years who underwent horizontal distraction osteogenesis DO and a final implant prosthesis. MATERIAL AND METHODS: A total of 13 sites in 12 patients (three men, nine women; mean age 45.4 years, range 21-63 years) who presented with severe horizontal atrophy of a partially edentulous maxilla or mandible were treated using horizontal DO. The horizontal distraction device was set on the transport bone which was osteotomized as bone splitting method and fixed to the segment using microscrews. RESULTS: The median of latency period was 9 days (range: 7-17); the median of amount of device activation was 5.6 mm (range: 4.4-9.6); the median of distraction period was 14 days (range: 8-24); and the median of consolidation period, from the end of activation until implant placement, was 13 weeks (range: 11-20). The median of actual gain in bone width at the end of the consolidation period was 3.6 mm (range: 1.1-5.6). A total of 35 implants were inserted in the augmented area with primary implant stability. The median of follow-up from the start of prosthetic loading was 5.4 years. Consequently, the implant survival and success rates were 100% and 94.2%, respectively. CONCLUSION: This article reports the long-term results of horizontal alveolar DO using a mesh device for patients with an atrophic alveolar region. Our results confirm that this technique is a predictable and effective regenerative procedure for implant preprosthetic treatment in patients with severe horizontal atrophy of the alveolar ridge.

Alveolar ridge reconstruction with titanium mesh and autogenous particulate bone graft: computed tomography-based evaluations of augmented bone quality and quantity.

PURPOSE: The purpose of this study was to evaluate the quality and quantity of augmented bone following alveolar ridge reconstruction with titanium mesh and autogenous particulate bone graft for implant placement in terms of the preoperative bone defect. MATERIALS AND METHODS: Forty-one patients (50 sites) rehabilitated between September 2000 and May 2009 with autogenous particulate intraoral bone or iliac cancellous bone marrow grafts and micro-titanium meshes were enrolled. We classified the bone defects by means of shape as complex horizontal-vertical (HV), horizontal (H), and socket (S) types, and the augmented bone was evaluated based on preoperative computed tomographic data. The postsurgical complications were assessed during the healing period and after implant superstructure placement. RESULTS: The bone defects were successfully augmented using the titanium mesh technique. The HV-type defect was the most difficult to augment (mean horizontal gain, 3.7 ± 2.0 [SD] mm; mean vertical gain, 5.4 ± 3.4 [SD] mm). The mean horizontal gain with the H-type defect was 3.9 ± 1.9 mm. The S-type defect achieved the most efficient bone augmentation (mean horizontal gain, 5.7 ± 1.4 [SD] mm; mean vertical gain, 12.4 ± 3.1 [SD] mm). The major postsurgical complications were mesh exposure, infection, total or partial bone resorption, and temporary neurological disturbances. Implant failure was observed in one case. The HV-type defect showed significantly higher bone resorption (p < .05) than the other defect types. CONCLUSIONS: Autogenous bone grafting with titanium mesh allows adequate vertical and horizontal alveolar bone reconstruction both quantitatively and qualitatively for implant placement. However, the clinical outcome of augmentation depends on the type of preoperative bone defect.

Implant placement for periosteal expansion osteogenesis using beta-tricalcium phosphate block: an experimental study in dogs.

OBJECTIVES: This study was performed to evaluate the clinical outcome of periosteal expansion osteogenesis for correction of a horizontally deficient alveolar ridge, stability of dental implants placed in the expanded areas, and osteocompatibility of beta-tricalcium phosphate (beta-TCP) block areas. STUDY DESIGN: The mandibular premolars were extracted and buccal corticotomy was performed in 5 female dogs. Narrow alveolar ridge models were produced at 10 weeks. The beta-TCP block was placed at the lateral surface of the mandibular bone and 2 titanium screws were inserted from the lingual aspect to push the block to the buccal side. After a latency period of 8 days, during which time primary wound healing occurred, the lingual screws were advanced by approximately 0.5 mm/day for 6 days. The expansion areas were left untreated for 8 weeks. Then implants (diameter 3.5 mm, length 9 mm) were inserted into the gap between the beta-TCP block and the original alveolar bone. We evaluated the changes in alveolar width, resonance frequency analysis of implants, and histomorphometric analysis of the beta-TCP block. RESULTS: No problems with the materials were observed at any of the sites of intervention before, during, or at the end of the experimental period. The width increased after expansion and showed stable results on week 8 from the end of expansion. Implants were placed in the expansion area and showed sufficient stability with slight increases in the implant stability quotient value until 8 weeks after implant placement. The amount of remaining beta-TCP decreased significantly compared with the original amount of material inserted. The mean values remaining inside the block were 44.6 +/- 8.2% and 32.1 +/- 12.0% at 8 and 16 weeks of consolidation, respectively, whereas newly formed bone comprised 20.2 +/- 7.2% and 33.5 +/- 9.5%, respectively. CONCLUSIONS: Newly formed bone could be acquired by periosteal expansion osteogenesis using a beta-TCP block for implant placement in a dog model. However, the bone volume was not stable after implant placement despite sufficient implant stability for 8 weeks.

Horizontal alveolar ridge augmentation using distraction osteogenesis: comparison with a bone-splitting method in a dog model.

OBJECTIVE: Although horizontal alveolar distraction osteogenesis (DO) appears to be a viable option for implant placement in a narrow alveolar ridge, relatively few reports exist on horizontal DO. Horizontal DO using a titanium mesh plate is similar to alveolar bone splitting, but without a bone graft. Therefore, this study compared 2 methods of bone augmentation, horizontal DO and a bone-splitting (BS) method with bone graft, using an experimental dog model. STUDY DESIGN: Five beagle dogs were studied. The experiments were designed in a spit-mouth manner. One side of the alveolar ridge of the mandible was 4 mm expanded using horizontal DO, followed by implant placement 2 months after augmentation. The other side of the ridge of the mandible was 4 mm augmented using a bone splitting (BS) method with a bone graft combined with simultaneous implant placement. RESULTS: The average amount of bone gain on the DO side (2.7 mm) was significantly greater than that on the BS side (1.7 mm) (P = .008) The keratinized soft tissue gain on the DO side (2.8 mm) was significantly greater than that on the BS side (0.6 mm) (P = .02). Resonance frequency analysis revealed that implants placed in the distracted area achieved good stability compared with those on the BS side. The implants were fully embedded in mature lamellar bone, and direct bone contact with the implant surface was seen 3 months after implant placement in the distracted area. CONCLUSIONS: Horizontal alveolar ridge distraction appears be an effective technique for the placement of implants in a narrow alveolar ridge.

Periosteal expansion osteogenesis using highly purified beta-tricalcium phosphate blocks: a pilot study in dogs.

BACKGROUND: In highly atrophic edentulous jaws, the augmentation of the alveolar process is standard treatment for dental implantation because of the lack of alveolar bone height and width. Our aim was to examine periosteal expansion osteogenesis in a dog model, based on the concept of distraction osteogenesis, using a highly purified beta-tricalcium phosphate (beta-TCP) block instead of an original bone segment. METHODS: Three beagle dogs weighing 10 to 12 kg were used. The beta-TCP block was placed at the lateral surface of the mandibular bone. Two titanium screws were inserted from the lingual aspect to push the block to the buccal side. After a latency period of 8 days, during which primary wound healing occurred, the lingual screws were advanced by approximately 0.5 mm/day for 8 days. Specimens were taken 8 weeks after lingual screw adjustments ceased and were analyzed by hematoxylin and eosin, tartrate-resistant acid phosphatase (TRAP), and Villanueva bone staining. RESULTS: The alveolar form at the experimental region was changed dramatically following lateral expansion with the beta-TCP block. Newly formed bone was observed in the gap between the bone and the beta-TCP block, as well as on the lateral surface of the block. Moreover, the replacement of large parts of beta-TCP with newly formed bone was observed in the beta-TCP block area. However, newly formed bone was not observed over the upper parts of the block, and multinucleated TRAP-positive cells were attached to the beta-TCP in the periphery of this area. CONCLUSION: The highly purified beta-TCP block worked as an activator for the soft tissue, including the periosteum, as well as a space maker to induce an osteoblastic response in the periosteum.

Magnet-retained facial prosthesis combined with an implant-supported edentulous maxillary obturator: a case report.

The prosthetic rehabilitation of maxillofacial defects is especially challenging when the patient is edentulous. Although dental implants are used to enhance the retention and stability of both facial and maxillary prostheses, combining facial and maxillary prostheses is extremely difficult. This article describes the prosthetic treatment of an edentulous patient with a large maxillary and facial defect. After placing dental implants in the remaining maxilla, a maxillary obturator prosthesis supported by a milled bar attachment was fabricated. The facial prosthesis was retained by a magnetic attachment to the maxillary obturator prosthesis. As the obturator prosthesis was supported securely by this sturdy attachment, the facial prosthesis was stable during mastication and facial movement. The patient reported improvement in prosthesis retention and stability. Both the masticatory and the speech functions of the patient improved.

The relationship of the histologic grade at the deep invasive front and the expression of Ki-67 antigen and p53 protein in oral squamous cell carcinoma.

BACKGROUND: Although many histopathologic characteristics of oral squamous cell carcinoma (O-SCC) have been identified as prognostic factors, accurate, and unequivocal factors have not been clearly identified. The purpose of this study was to evaluate a potential association between the histologic grade of malignancy at the deep invasive front and the expression of Ki-67 antigen and p53 protein in O-SCC. METHODS: The expression of Ki-67 antigen and p53 at the invasive tumor front area of O-SCC was examined by immunohistochemistry of archived tissue from 62 cases. The mean age of patients was 60.7 years (range: 37-89) and the male-female ratio was 1.6:1 (38 men, 24 women). There were 20, 17, 14, and 11 cases classified as stage I to stage IV, respectively. The correlation between the intensity of immunostaining for Ki-67 antigen and p53 and the histologic grade of malignancy at the deep invasive front (invasive front grade, IFG) was analyzed. The expression of Ki-67 antigen and p53 in normal oral epithelia (10 cases) was also investigated. RESULTS: The mean Ki-67 labeling index (LI) in the O-SCC samples was 32.8 +/- 12.0% (n = 62). The mean total score of IFG (IFG score) was 9.1 +/- 2.7 points (n = 62). There was a significant linear correlation between the IFG score and the Ki-67 antigen (gamma = 0.651, R2 = 0.596, P < 0.0001). Of 50 tumors examined, 27 (54.0%) exhibited p53-positive nuclear immunostaining. The staining patterns for Ki-67 antigen and p53 were similar. Both Ki-67-LI and p53-positive status were significantly correlated with the IFG scores. CONCLUSION: The findings of this study demonstrate that overexpression of Ki-67 antigen and p53 at the deep tumor invasive front of O-SCC is associated with histologic grade of malignancy.

Use of horizontal alveolar distraction osteogenesis for implant placement in a narrow alveolar ridge: a case report.

Although alveolar distraction is a promising method for ridge augmentation involving the atrophic maxilla or mandible for implant placement, techniques of horizontal and oblique alveolar distraction for expanding a narrow alveolar ridge have not been established. A case of horizontal alveolar distraction for implant placement using a titanium mesh plate and a distraction screw is reported. Horizontal alveolar distraction was performed on a patient with an extremely atrophic alveolar ridge in the anterior mandibular region. Two transport segments using horizontal osteotomies were prepared, and 2 horizontal alveolar distraction devices were inserted. After a 7-day waiting period, the devices were activated and alveolar widening was performed labially (0.225 mm twice a day for 14 consecutive days). Three months after consolidation, the distraction devices were removed. The distracted areas were completely filled with newly formed solid bone tissue. Two months after the device was removed, 4 endosseous implants were placed and an implant-supported definitive prosthesis was placed. This method of horizontal alveolar distraction appears to be clinically useful for the placement of implants in atrophic or knife-edged alveolar ridges.

Distraction osteogenesis for reconstruction after mandibular segmental resection.

Distraction osteogenesis with the shortening and lengthening method is a well-established procedure for repairing extremities. We used this technique for reconstruction after mandibular segmental resection. A 74-year-old woman underwent distraction osteogenesis with an intraoral device, initially shortening the mandible after a 20-mm-long segmental resection, followed by lengthening at a rate of 0.8 mm per day for 21 days. Eight weeks after the distraction, the device was removed and a dental implant was placed at the site of distraction. Radiographic observation showed new bone formation, and the implant was completely osseointegrated. Although the follow-up period is relatively short, the clinical course was uneventful. Distraction osteogenesis with the shortening and lengthening method seems to be a feasible option for reconstruction after segmental resection of the mandible.