Kang-Min Ahn

Simultaneous sinus lift and implant installation: prospective study of consecutive two hundred seventeen sinus lift and four hundred sixty-two implants.

PURPOSE If less than 4 mm of residual bone is remained in posterior maxilla, two-stage operation is recommended for implant installation. However, if primary stability could be obtained using tapered designed implants, one-stage surgery could be performed with reliable success rate in severely resorbed maxilla. The purpose of this prospective study was to evaluate survival and success rates of the implants simultaneously placed into grafted sinus using rough-surfaced implant. MATERIALS AND METHODS A total of two hundred seventeen consecutive sinus lifting through lateral approach and four hundred sixty-two simultaneous implants were installed from November 2003 for 5.5 years. Xenogenic bone was used solely for bone graft materials. Second surgery was performed around 6 months after operation and porcelain fused metal or gold crown was used for definitive restorations. Cumulative survival and success rates were evaluated according to residual alveolar bone height (RABH), smoking status, and Schneiderian membrane perforation. RESULTS The mean follow-up was 57.1 ± 15.6 (36-98) months. Of the four hundred sixty-two implants, two hundred sixty-two implants (56.7%: group 1) were installed in posterior maxilla less than 4-mm RABH and two hundred implants (43.3%: group 2) were placed in over 5-mm RABH. The cumulative survival and success rates were 98.91% and 96.54%. There was no statistically significant difference in success rate between group 1 and group 2 (p = .3135). Perforation of the membrane was not related to success (p = .7162), but smoking status is significantly related with implant failure (p = .0003). CONCLUSIONS Sinus lifting with simultaneous implant placement could be used to treat atrophic maxilla in patients with minimal RABH when initial stability could be obtained by using taper designed implants with surgical techniques. Smoking is a possible factor for implant failure. Membrane perforation did not have an adverse effect on implant success if the membrane was repaired with absorbable membrane and fibrin glue.

Immediate free iliac bone graft after nonsegmental mandibular resection and delayed implant placement: a case series.

Background:Resection of mandibular tumors without proper reconstruction may lead to unfavorable esthetic and function results. The purpose of this case series was to describe clinical results and a technique to prevent tissue loss using nonvascular iliac grafts immediately following tumor resection and long-term stability of the implants. Materials and Methods:Three female patients presented with oral neoplasms (2 ameloblastoma and 1 ossifying fibroma). The mandibular reconstruction was performed with nonvascularized iliac grafts simultaneous with tumor removal. Subsequently, 10 dental implants were placed 6 to 9 months after reconstruction and restored. Survival and success of the implants were evaluated. Results:Marginal mandibulectomy in 1 patient and buccal bone resection in 2 patients was performed; the resection sites were reconstructed with an immediate nonvascularized iliac graft. All implants survived and were successful during follow-up periods between 44 and 105 months. Mean marginal bone loss of 10 implants was 0.09 mm. Conclusions:Immediate reconstruction with nonvascularized iliac grafts following tumor resection may be a viable treatment option for nonsegmental inlay osseous defects. In these case series, the resorption of the iliac bone was minimal after 6 to 9 months consolidation periods.

Osteonecrosis of the jaw after implant surgery in patients treated with bisphosphonates--a presentation of six consecutive cases.

BACKGROUND Osteonecrosis of the jaws in patients treated with bisphosphonates is mostly associated with intravenous bisphosphonates while the incidence associated with oral bisphosphonates is not significant. PURPOSE The purpose of this paper is to describe a series of cases of jaw osteonecrosis that may be associated with dental implant placement in patients who had taken nitrogen containing bisphosphonates via oral and/or intravenous route. PATIENTS Six female patients were treated for osteonecrosis of the jaw after implant placement. An average age was 71.8 ± 6.5 years old and they had a history of bisphosphonate use. Two patients suffered from cancer and the other patients had osteoporosis. Two osteoporosis patients had taken only oral bisphosphonate and the other patients received intravenous bisphosphonates. RESULTS Resection of necrotized bone, implant removal, and primary closure were performed in five patients and four patients showed uneventful healing. One patient presented recurrence at the maxilla and underwent further extraction and resection. One patient presented with an exposure of the bone after implant placement was treated with an advanced flap closure, and the implants were preserved. CONCLUSION Unusual jaw necrosis after dental implant surgery might be related with oral and/or intravenous bisphosphonates. Wide resection of necrotic bone, collagen graft, and primary closure are key factors for successful healing.

Effect of silane activation on shear bond strength of fiber-reinforced composite post to resin cement.

PURPOSE Among the surface treatment methods suggested to enhance the adhesion of resin cement to fiber-reinforced composite posts, conflicting results have been obtained with silanization. In this study, the effects of silanization, heat activation after silanization, on the bond strength between fiber-reinforced composite post and resin cement were determined. MATERIALS AND METHODS Six groups (n=7) were established to evaluate two types of fiber post (FRC Postec Plus, D.T. Light Post) and three surface treatments (no treatment; air drying; drying at 38℃). Every specimen were bonded with dual-curing resin cement (Variolink N) and stored in distilled water for 24 hours at 37℃. Shear-bond strength (MPa) between the fiber post and the resin cement were measured using universal testing device. The data were analyzed with 1-way ANOVA and by multiple comparisons according to Tukeys HSD (α=0.05). The effect of surface treatment, fiber post type, and the interactions between these two factors were analyzed using 2-way ANOVA and independent sample T-tests. RESULTS Silanization of the FRC Postec Plus significantly increased bond strength compared with the respective non-treated control, whereas no effect was determined for the D.T. Light Post. Heat drying the silane coupling agent on to the fiber-reinforced post did not significantly improve bond strength compared to air-syringe drying. CONCLUSION The bond strength between the fiber-reinforced post and the resin cement was significantly increased with silanization in regards to the FRC Postec Plus post. Bond strength was not significantly improved by heat activation of the silane coupling agent.

Full mouth rehabilitation on a bilateral condylar fractured patient using orthognathic surgery and dental implant

BACKGROUND Mandibular displacement is a common complication of condylar fracture. In the mandibular displacement due to condylar fracture, it is difficult to restore both esthetics and function without using orthognathic surgery. CASE DESCRIPTION This clinical report described a full mouth rehabilitation in the patient with bilateral condylar fractures and displaced mandible using bilateral sagittal split ramus osteotomy (BSSRO) and simultaneous dental implant surgery. Mandibular position was determined by model surgery through the diagnostic wax up and restoration of fractured teeth. The precise amount of the mandibular shift can be obtained from the ideal intercuspation of remaining teeth. CLINICAL IMPLICATION Mandibular displacement by both condylar fractures can be successfully treated by orthognathic surgery. Determination of occlusal plane and visualization from diagnostic wax up are mandatory for mandibular repositioning of model surgery. Stable occlusion and regular recall check up are needed for long-term outcome.

Accidental Migration of a Dental Implant into the Ethmoid Sinus following a Transalveolar Sinus Elevation Procedure

BACKGROUND Migration of a dental implant into the paranasal sinuses may be the result of sinus membrane perforation, loss of osseointegration, and lack of initial stability. The majority of displaced implants migrate into the maxillary sinus, which may cause sinusitis. PURPOSE The purpose of this study is to report an extremely rare ethmoid sinus migration of a dental implant after crestal approach in a resorbed posterior maxilla. MATERIALS AND METHODS A 60-year old Korean male with a noncontributory medical history was referred from a local clinic to remove the migrated dental implant in the right ethmoid sinus. The patient had symptoms of mild sinusitis. The implant had been placed 6 months earlier through the bone-added transalveolar approach in a severely resorbed maxilla. RESULTS The displaced implant was removed through the intraoral approach. A lateral window was made and an endoscopic surgery was performed to remove the implant. Healing was uneventful, and sinusitis symptom had ceased. CONCLUSION The crestal approach for severely resorbed posterior maxillae should be performed when there is a potential for primary stability. If bone quality is poor and initial stability cannot be achieved, lateral window sinus elevation procedure is a better option for successful implant placement. Migrated implant may be removed with antrostomy and endoscopic surgery.

Endoscopic removal of an aspirated healing abutment and screwdriver under conscious sedation.

Purpose:Aspiration of foreign bodies during dental treatment is a medical emergency that requires prompt removal. In this study, aspiration of screwdriver and healing abutment is reported with literature review. Materials and Methods:A 26-year-old male patient was referred from a local dental clinic with the suspicion of ingestion of a screwdriver and healing abutment during the second-stage surgery. The patient reported symptoms including dyspnea, cough, and foreign body sensation. On the chest radiograph, a radiopaque foreign body resembling the screwdriver and healing abutment was observed at the right mid lung. Results:Bronchoscopic examination using flexible cable was performed under conscious sedation, and microforceps were used to remove the instruments. Aspirated screwdriver and healing abutment were removed safely under intravenous sedation. The patient did not have any symptoms associated with lung aspiration after removal of the foreign body during follow-up periods. Conclusion:Bronchoscopic removal is the most recommended procedure for removal of the aspirated foreign body. This can be performed under conscious sedation. Precautions, such as tethering the screwdriver, are recommended during implant procedures.

Effects of hydrogen peroxide pretreatment and heat activation of silane on the shear bond strength of fiber-reinforced composite posts to resin cement

PURPOSE To evaluate the effects of hydrogen peroxide pretreatment and heat activation of silane on the shear bond strength of fiber-reinforced composite posts to resin cement. MATERIALS AND METHODS The specimens were prepared to evaluate the bond strength of epoxy resin-based fiber posts (D.T. Light-Post) to dual-curing resin cement (RelyX U200). The specimens were divided into four groups (n=18) according to different surface treatments: group 1, no treatment; group 2, silanization; group 3, silanization after hydrogen peroxide etching; group 4, silanization with warm drying at 80℃ after hydrogen peroxide etching. After storage of the specimens in distilled water at 37℃ for 24 hours, the shear bond strength (in MPa) between the fiber post and resin cement was measured using a universal testing machine. The fractured surface of the fiber post was examined using scanning electron microscopy. Data were analyzed using one-way ANOVA and post-hoc analysis with Tukeys HSD test (α=0.05). RESULTS Silanization of the fiber post (Group 2) significantly increased the bond strength in comparison with the non treated control (Group 1) (P<.05). Heat drying after silanization also significantly increased the bond strength (Group 3 and 4) (P<.05). However, no effect was determined for hydrogen peroxide etching before applying silane agent (Group 2 and 3) (P>.05). CONCLUSION Fiber post silanization and subsequent heat treatment (80℃) with warm air blower can be beneficial in clinical post cementation. However, hydrogen peroxide etching prior to silanization was not effective in this study.