Fig. 5. Intraoral view after Dentis implants on by Fab Bor

Part

Fig. 5. Intraoral view after Dentis implants on #44 - #46 (#44 : 3.7mm in diameter and 12mm long, #45 : 4.3mm in diameter and 10mm long, #46 : 4.3mm in diameter and 12mm long).

Fig. 7. Radiograph before second surgery.

Fig. 9. Intra-oral view after removal of healing abutment for taking impression.

Fig. 6. Post-surgical radiograph after placement of the Dentis implant.

Fig. 8. Radiograph after second surgery.

Fig. 10. Pick-up impression taking by impression coping and connection of lab analogue.

171

Fig. 11. Intra-oral view after abutment try-in.

Fig. 12. Intra-oral view after temporary setting.

Fig. 13. Intra-oral view after permanent setting.

Fig. 14. Intraoral view at 1 year after installation of the final prosthesis.

Fig. 15. Panoramic view at 1 year after installation of the final prosthesis.

172

6. Guided bone regeneration (GBR) Age / gender â&#x2013;ś 62 years / female

Part

Diagnosis and treatment plan â&#x2013;ś The defect in the right molar tooth and teeth #42, #43, #45, #46 were restored by prosthesis with the placement of a Dentis implant after GBR using by Tutoplast.

Fig. 1. X-ray taken before implant surgery.

Fig. 3. Photograph showing the occlusal relationship before incision and subsequent reflection of the flap.

Fig. 2. Pre-surgical photograph of the intraoral view.

Fig. 4. Intraoral view with surgical stent.

173

Fig. 5. Intraoral view with surgical stent showing the occlusal relationship before incision and subsequent reflection of the flap.

Fig. 7. Photograph after drilling.

Fig. 8a. Dentis implant.

Fig. 8b. Photograph after implant placement (#42 : 3.7mm in diameter and 8mm long, #43, #45, #46 : 4.3mm in diameter and 8mm long).

Fig. 8c. Dentis implant.

Fig. 9. Perforation of buccal cortical bone in the recipient site.

174

Fig. 6. Photograph after incision and subsequent reflection of the flap.

Fig. 10. Transplanting bone material (tutoplast).

Part

Fig. 11. Placement of pericardium membrane.

Fig. 12. Intraoral view after suture.

Fig. 13. X-ray taken after placement of the Dentis implant.

Fig. 14. Radiograph taken after 3 months.

Fig. 15. Panoramic view before second surgery.

Fig. 16. Radiograph after second surgery.

Fig. 17. Panoramic view at 1 year after installation of the final prosthesis.

175

7. Overdenture (1) Age / gender ▶ 73 years / female

Chief complaint ▶ lower denture unsatisfaction, ▶ treatment plan : Implant overdenture

Fig. 1. X-ray taken before the implant.

Fig. 3. Intraoral view after incision and subsequent reflection of the flap.

Fig. 5. Panoramic view after placing a Dentis implant.

176

Fig. 2 Intraoral view before surgery.

Fig. 4. Intraoral view after placing a Dentis implant (3.7mm in diameter and 10mm long).

Fig. 6. Hyperplastic gingiva on left mandible.

Part

Fig. 7. Nd:YAG (Neodymium-doped YttriumAluminium-Garnet) laser (Anybeam ENTM, B&B Systems, http://dental.bnbsys.co.kr).

Fig. 8. Removal of gingiva using Nd:YAG laser.

Fig. 9. Intraoral view at 1 week after Nd:YAG laser treatment.

Fig. 10. Intraoral view at 2 weeks after Nd:YAG laser treatment.

Fig. 11. Intraoral view at 3 weeks after Nd:YAG laser treatment.

Fig. 12. Intraoral view at 4 weeks after Nd:YAG laser treatment.

Fig. 13. Radiograph before second surgery (4 months after implant placement).

Fig. 14. Intraoral view before second surgery.

177

Fig. 15. Intraoral view after incision and sebsequent reflection of the flap.

Fig. 17. Radiograph after second surgery.

Fig. 18. Intraoral view at 3 weeks after second surgery.

Fig. 19. Panoramic view at 3 weeks after second surgery.

Fig. 20a. Intraoral view at 1 year after installation of the final prosthesis.

Fig. 20b. Intraoral view at 1 year after installation of the final prosthesis.

178

Fig. 16. Intraoral view after second surgery.

Fig. 21. Panoramic view at 1 year after installation of the final prosthesis.

Overdenture (2) Age / gender ▶ 74 years / female

Part

Chief complaint ▶ root rests on #32, #33, #42, #43, ▶ treatment plan : implant overdenture after extraction of root rests

Fig. 1. X-ray taken before the implant.

Fig. 3. Intraoral view after incision and subsequent reflection of the flap.

Fig. 2 Intraoral view before surgery.

Fig. 4. Intraoral view after placing Dentis implants (#32, #42 : 3.7mm in diameter and 12mm long, #34, #44 : 4.3mm in diameter and 10mm long).

179

Fig. 5. Exposure of threads around #33 implant.

Fig. 7. Intraoral view after suture.

Fig. 8. Panoramic view after placing a Dentis implant.

Fig. 9. Intraoral view at 3 months after placing a Dentis implant.

Fig. 10. Radiograph at 3 months after placing a Dentis implant.

Fig. 11. Radiograph before second surgery (4 months after implant placement).

180

Fig. 6. Transplanting bone material (tutoplast) into the exposed threads.

Fig. 12. Intraoral view before second surgery.

Part

Fig. 13. Intraoral view after incision and sebsequent reflection of the flap.

Fig. 14. Intraoral view after second surgery.

Fig. 15. Radiograph after second surgery.

Fig. 16a. Intraoral view at 1 year after installation of the final prosthesis.

Fig. 16c. Intraoral view at 1 year after installation of the final prosthesis.

Fig. 16b. Intraoral view at 1 year after installation of the final prosthesis.

Fig. 17. Panoramic view at 1 year after installation of the final prosthesis.

181

8. Horizontal alveolar bone distraction using a distractor Age / gender â&#x2013;ś 26 years / male

Diagnosis and treatment plan â&#x2013;ś mesiodistal width deficiency in the area of teeth #24~#26 were prosthetically restored by placing a Dentis implant after DO (distraction osteogenesis).

Specific characteristics â&#x2013;ś DO is a surgical method of bone formation that involves an osteotomy and sequential stretching of the healing callus by gradual movement and sequent remodeling.

Fig. 1. X-ray taken before implant surgery.

Fig. 2. Intraoral view showing distrator placement.

182

Part

Fig. 3. X-ray view after distrator placement.

Fig. 4. Panoramic view after DO finishing.

Fig. 5. Intraoral view 9 months after distrator placement.

Fig. 6. Intraoral view showing the occlusal relationship at 9 months after distrator placement.

Fig. 7. Radiograph taken before implant placement.

183

Fig. 8. Intraoral view before removal of the distractor.

Fig. 9. Photograph showing the occlusal relationship before removal of the distractor.

Fig. 11. Intraoral view after remove of the distractor.

184

Fig. 10. Intraoral view after incision and subsequent reflection of the flap.

Fig. 12. Removed distractor.

Part

Fig. 13a. Dentis implant.

Fig. 13b. Placement of Dentis implant on #26 (4.3mm in diameter and 12mm long).

Fig. 13c. Dentis implant.

Fig. 14. Radiograph taken after implant placement.

Fig. 15. Radiograph taken before second surgery.

185

Fig. 16. Intraoral view before second surgery.

Fig. 17. Photograph showing the occlusal relationship before second surgery (6.5 months after implant placement).

Fig. 18. Intraoral view after incision and subsequent reflection of the flap.

Fig. 19. Intraoral view after suture. periotest : -2, -2, -2.

Fig. 20. Intraoral view showing the occlusal relationship after suture.

186

Fig. 21. Radiograph taken after second surgery.

Part

Fig. 22. Intraoral view at 1 year 6 months after installation of the final prosthesis.

Fig. 23. Radiograph at 1 year 6 months after installation of the final prosthesis.

187

Part.

Published Articles

Implant placement using the SAVE implant Part

SUMMARY Implants with wide diameters, greater than or equal to 4.5 mm, have been developed for specific bone and prosthetic situations, including poor bone quality, insufficient ridge height, a single missing molar, immediate replacement of a non-osseointegrated or fractured implant, and immediate implant placement following tooth extraction. I introduce characteristics of the SAVE fixture and application of the SAVE fixture.

Introduction Implant diameter selection depends on the following parameters: residual bone volume, bone quality, anchoring surface, anatomy of the replaced tooth, available mesiodistal space, prosthetic emergence profile, and biomechanical factors 1). Different implant diameters have been proposed since the late 1980s 1). During the past 10 years, the development of new surgical and prosthodontic components has allowed optimization of functional and esthetic results. The use of small-diameter implants is not recommended in the presence of poor-density bone. Implants with wide diameters, greater than or equal to 4.5 mm, have been developed for specific bone and prosthetic situations, including poor bone quality, insufficient ridge height, a single missing molar, immediate replacement of a non-osseointegrated or fractured implant, and immediate implant placement following tooth extraction1). Published Articles Implant placement using the SAVE implant

Key words : Implant placement, SAVE implant, wide diameters Implant placement using the SAVE implant ď˝&#x153;

191

Characteristics of the SAVE fixture 1. The SAVE fixture is a switching platform method (Fig. 1) whose application to the fixture shoulder area can minimize the loss of alveolar bone.

Fig. 1. Switching platform method.

2. This is a micro-thread to prevent bone loss (Fig. 2). Even in thin cortical bones, it mediates a wedge effect. Together with primary stability, it helps to minimize bone loss by appropriate stimulation of cortical bone and distribution of stress. It has also been shown to play a role in preventing cortical bone resorption caused by bacterial infection.

Fig. 2. Micro-thread.

3. This shows the safe cutting edge/tapered design (Fig. 3), which minimizes bone resistance and allows safe and smooth implantation. Double threads were selected for the tapered design, and, in addition to the cutting edge of the lower part of the screw, a microcutting edge was added along the rotation direction of the entire thread. Using this device, along with the application of constant force, excessive friction on the bone is noticeably reduced, allowing smooth and stable implantation. The device was also designed to achieve high initial fixation and excellent bone union.

192

Part

Fig. 3. Safe cutting edge/tapered design.

4. Convenient abutment compatibility (Fig. 4) The additional SAVE abutment system is not required, and existing products can be used. The availability of compatible abutments from other companies (Astra, Osstem Implant, Dentium) makes the SAVE fixture an economical choice.

Hex

N-Hex

Fig. 4. Couple abutment with convenient abutment compatibility.

5. Optimal RBM surface treatment (Fig. 5) A resorbable blast medium (RBM) method is favored because the surface of the fixture is inserted to the alveolar bone, and a surface roughness value of approximately 1.5 m provides an ideal value for osseointegration.

Fig. 5. Optimal RBM surface treatment.

Implant placement using the SAVE implant ď˝&#x153;

193

6. No-mount system (Fig. 6) The SAVE fixture no-mount system directly assesses the path during surgery and is not influenced by adjacent teeth, thus allowing shorter operation time and accurate surgery.

Fig. 6. No-mount system.

Application of the SAVE fixture 1. When the depth of alveolar bone is not sufficient, properly sized fixtures can be implanted through alveolar augmentation. However, for cases in which an appropriate healing time or suitable systemic condition cannot be achieved due to health conditions or personal situations of patients, an implant appropriate to the existing alveolar bone must be selected. Furthermore, if sufficient surface length cannot be obtained, a wide-diameter fixture should be selected to maximize the surface available for osseointegration in order to form a final prosthesis able to withstand the occlusal load. 2. If a necessary initial fixation is not obtained because of the loss of a wide fixture or the widening of the alveolar bone during surgery, two treatment options are generally considered: postpone implantation until alveolar bone is formed or treat the extraction socket to promote bone formation. Either option requires a wait of more than 3 months before implantation can be attempted again. However, by using the newly developed SAVE fixture, implantation can be performed immediately, and sufficient initial fixation can be obtained, allowing the successful completion of the implantation. The SAVE kit includes a final drill kit for both internal and submerged implantation. It is a surgical kit with 5.5 diameter and 6mm diameter exclusively for fixture. As for emergency treatment, it has only a final drill. The no-mount driver is identical to the dentistâ&#x20AC;&#x2122;s existing driver and is constructed to allow shorter operation time and accurate surgery. It is a convenient stopper-attached drill, with basically a rotation-type stopper attached to the drill. In addition, the very hard tungsten monocarbide (WC) coating of the drill increases its drilling power. The length of the short stopper can be easily adjusted to 2, 4, or 6mm according to removal and application, and 8mm. The length of the long stopper can be easily adjusted to 2 or 4mm according to removal and application, and 10 or 12mm. The removal and application of the stopper can be smoothly and easily accomplished, and it is a rotation type during contact with the bone, thus decreasing surgical trauma to the alveolar bone.

194

Discussion The diameter, length, and stability of an endosseous dental implant at placement are critical factors in achieving and maintaining osseointegration. In the event of slight implant mobility at placement, the conventional or accepted treatment is to place a longer implant and/or one of wider diameter2). The most commonly used standard-diameter dental implant is inadequate in patients with poor bone quality or quantity, and wider-diameter implants have been used to overcome these bone deficiencies3). Kido et al.3) reported that wider-diameter implants appear to have advantages over smaller-diameter implants. However, more extensive testing is needed to quantitatively determine the increased load-carrying capacity of wider-diameter implants. Good results can be achieved using thick implants in posterior areas where the width of the bucco-lingual alveolar crest is sufficient, and initial fixation by cortical bone can be achieved after implantation. However, thick implants do not always guarantee success, and some investigators have reported failures. In a survey data analysis that excluded prosthesis type from the modeling process, Scurria et al.4) reported that posterior location and implant width < 4.0 mm were associated with implant failure (all Pă&#x20AC;&#x2C6; 0.05). In the molar areas, widediameter implants may withstand the occlusal force and may evenly distribute the force, owing to the wide surface area. Nonetheless, if the implant is too wide, initial bone union may be impaired because of insufficient blood supply and a prolonged implant healing period. Therefore, it is desirable to carefully choose an implant based on the bone condition and volume. Aparicio and Orozco5) reported the installation of 185 machined-screw implants (Nobel Biocare, Gothenburg, Sweden) in 45 patients, to strengthen 58 prostheses. Of these, 91 implants were 3.75 mm in diameter, and 94 were 5.0 mm wide. They retrospectively evaluated indications, marginal bone remodeling, Periotest values (PTvs), and survival rates. PTv and radiographic measurements were made at abutment connections and were repeated 3, 6, and 12 months later, and every year thereafter. The follow-up period ranged from 16 to 55 months (mean, 32.9 months) post-loading. The cumulative success rates (CSR) with the 5.0-mm implant were 97.2% in the maxilla and 88.4% in the mandible after 1 year of function, and 97.2% and 83.4% in the maxilla and mandible, respectively, after 48 months. The PTvs in the maxilla and mandible were 1.1 and 0.6 units lower, respectively, with the 5.0-mm implant than with the 3.75-mm implant in the same patients. The PTv results support the hypothesis that the damping capacity of the bone surrounding a 5.0-mm implant differs from that surrounding a 3.75-mm implant. In a 3- to 5-year retrospective study involving 67 patients, aged 16~86 years, Ivanoff et al.6) focused on implant survival and marginal bone remodeling in relation to implant diameter. A total of 299 Branemark implants (141 with 3.75-mm diameter, 61 with 4.0-mm diameter, and 97 with 5.0-mm diameter) were placed in 16 completely and 51 partially edentulous arches. Seven (5%) of the 141 implants with 3.75-mm diameter failed, and two (3%) of the 61 implants with 4.0-mm diameter failed. The highest failure rate, 18% (17/97), occurred with the 5.0-mm implants. The least favorable CSRs occurred in mandibles after 5 years and involved the 4.0-mm- and 5.0-mm-diameter implants (CSR, 84.8% and 73.0%, respectively). The marginal bone loss was generally low over the 5-year period. Cox regression analysis revealed a relationship between implant failure and diameter (P < 0.05), with a higher failure rate for the 5.0-mm-diameter implants. However, no relationship was seen between implant failure and jaw type or between implant failure and bone quality/quantity (P > 0.05). According to the multiple linear regression analysis, there was no relationship between marginal bone loss and bone quality/quantity, implant diameter, or jaw type (P > 0.05). A learning curve, poor bone quality, and altered implant design have been suggested as possible reasons for the

Implant placement using the SAVE implant ď˝&#x153;

195

Part

less positive outcome seen with the 5.0-mm implant. Another plausible explanation is that the 5.0-mm implant was often used as a rescue implant when standard implants were not considered suitable or did not reach initial stability. Winkler et al.2) analyzed the data for 2917 implants that were placed, restored, and followedup. All implants with 3- to 3.9-mm diameters were pooled into a “3+”group, and all implants with 4- to 4.9-mm diameters were pooled into a“4+”group. The analysis indicated that implants with diameters of 3+ mm had a lower survival rate and were less stable (more positive PTvs) than those with diameters of 4+ mm. In addition, crestal bone loss between placement and uncovering did not differ significantly between the two different-diameter implants. After matching for several identified risk factors, Shin et al.7) compared 64 wide-bodied implants placed consecutively in the posterior jaws of 43 patients with 64 regular-diameter implants (3.75- or 4-mm diameter) placed in the posterior jaws of 25 of the same patients and 14 other patients. Ten of the wide-bodied implants failed (CSR, 80.9%), whereas only two of the regular-diameter implants failed (CSR, 96.8%). The difference between the groups was statistically significant. Wide-bodied implants placed in the posterior jaw can suffer a significantly elevated risk of implant failure in comparison with regular-diameter implants. This susceptibility may be related to implant design or to the relative relationship between the implant and host-bone dimensions.

References 1. Davarpanah M, et al: Clinical manual of implant dentistry. Quintessence. 2. Winkler S, et al: Implant survival to 36 months as related to length and diameter. Ann Periodontol, 5: 22, 2000. 3. Kido H, et al: Implant diameter and bone density: effect on initial stability and pull-out resistance. J Oral Implantol, 23: 163, 1997. 4. Scurria MS, et al: Prognostic variables associated with implant failure: a retrospective effectiveness study. Int J Oral Maxillofac Implants, 13: 400, 1998. 5. Aparicio C, Orozco P: Use of 5-mm-diameter implants: Periotest values related to a clinical and radiographic evaluation. Clin Oral Implants Res, 9: 398, 1998. 6. Ivanoff CJ, et al: Influence of variations in implant diameters: a 3- to 5-year retrospective clinical report. Int J Oral Maxillofac Implants, 14: 173, 1999. 7. Shin SW, et al: A retrospective study on the treatment outcome of wide-bodied implants. Int J Prosthodont, 17: 52, 2004.

196

Restoration of a partial edentulous ridge with a Dentis implant: A case report Part

Abstract The recent active development of domestic Korean implants has made them very competitive with imports. Although the domestic Dentis implant was developed in 2005, few studies have compared it to well-known overseas products. We believe that the relative lack of clinical research may make patients and dentists reluctant to use the Dentis implant. Here we present a case report of a patient missing multiple teeth who was treated with Dentis implants and a dental prosthesis to assess the stability of the domestically manufactured Dentis implant.

I. Introduction Based on the concept of osseointegration in the field of dental treatment promulgated by Branemark, prosthodontic restoration using implants gives a more clear-cut effect than other treatment methods in terms of fusing with completely edentulous bone, stability, and long-term prognosis. Consequently, it is presently used in most cases involving the loss of teeth, such as the loss of partial edentulous jaw or a single tooth. Numerous implants have been developed and are used worldwide, and further technical development is ongoing continuously. Implants have recently been developed in Korea and are competitive in an implant market that was dependent on imports. The market share of Korean implants has increased, and Dentis, which was developed in Korea in 2005, is one of such Korean implant product. The Dentis implant (Daegu, Republic of Korea) incorporates all of the Published Articles Restoration of a partial edentulous ridge with a Dentis implant: A case report

Key words : Dentis, Implant, Resorbable blasting media, Microthread, Root form design Restoration of a partial edentulous ridge with a Dentis implant: A case report ď˝&#x153;

197

advantages of previous implants. With the production of three types of implant, i.e., internal, external, and submerged types, it can be applied in diverse cases. The surface of the fixture is treated using resorbable blasting media (RBM) and the upper part of the fixture consists of microthreads. The root form design is used to improve the overall appearance of the fixture. In this study, Dentis implants were placed in the maxilla and mandible of a partial edentulous patient simultaneously and a dental prosthesis was completed. Good results were obtained, and the case is reported here.

2. Case report 1. Clinical findings A 47-year-old female visited our hospital with the chief complaint of partial tooth loss in the molar area. She had refused the use of dentures, and was referred to us from the Department of Prosthetic Dentistry for implant placement. She had lost teeth #14, #24 - 26, and #44 - 46. The patient had undergone a gastrectomy for gastric cancer 18 months ago, but was presently well, and she desired early recovery of occlusal function. She requested the use of a Korean implant restoration.

2. Radiographic findings (Fig. 1) Initial panoramic radiographs and root apex radiographs showed the loss of teeth #24 - 26 and #44 - 46, with residual roots in the area of #14 and #45. The volume of residual bone was sufficient for implant placement.

Fig 1. Panoramic view at first visit.

3. Treatment and outcome To shorten the treatment period, the patient requested that all seven implants be placed simultaneously. Therefore, we decided to place seven submerged-type Dentis implants simultaneously, and to perform guided bone regeneration (GBR) as needed. Two months before placing the implants, the residual dental roots of #14 and #45 were extracted. Under local anesthesia, a full thickness flap was lifted, and the implants were placed according to the bone height measured radiographically (Table 1). All implants showed good early osseointegration and were sutured using vicryl and nylon (Fig. 2). Postoperatively, antibiotics and analgesics were administered orally for 5 days to control pain and prevent infection, and the sutures were removed after 1 week. Three months later, at the time of the second

198

surgery, a well-healed scar was observed in the implant placement area and good osseointegration was confirmed radiographically. The seven maxillary and mandibular implants were then placed simultaneously, and after the second surgery, the Periotest was used to evaluate their stability. The value of the Periotest measured three times ranged from -2 to +6, and there was good osseointegration (Table 2). Temporary restoration was made after taking an impression (Fig. 3), and after functioning for 1 month, the final denture was placed permanently (Fig. 4). On the radiographs taken 1 month after placement of the final denture, the bone height was stable. The patient has expressed satisfaction with no discomfort or complications. Good occlusion was maintained (Fig. 5).

Table 1. Implant type, diameter, length, and grafting materials

Tooth No.

Type

Fixture diameter (mm)

Platform diameter (mm)

Length (mm)

Grafting material

#14

submerged

4.3

Bio-oss

#24

submerged

4.3

#25

submerged

4.3

#26

submerged

4.3

#44

submerged

4.3

4.7

#45

submerged

4.3

#46

submerged

4.3

Table 2. Periotest results Tooth No.

1st

2nd

3rd

#14

-4

-5

#24

-2

-3

-2

#25

-5

-4

-5

#26

-2

-3

-4

#44

-5

#45

-6

#46

-6

Fig 2. Panoramic view after primary surgery.

Restoration of a partial edentulous ridge with a Dentis implant: A case report ď˝&#x153;

199

Part

Fig 3. Prosthodontic procedures.

200

Part

Fig 4. Final restoration.

Fig 5. Panoramic view after 1 month final restoration.

3. Summary and Discussion Implants have various shapes depending on their macrostructure, microstructure, and abutment patterns. The ultimate purpose of implant design is to accelerate osseointegration. Depending on their macrostructure, implants can be classified as tapered and non-tapered types. The use of tapered-type implants allows firm early osseointegration as a result of the edge effect, pushing the bone laterally. Since they become narrower toward the root apex, the possibility of injuring adjacent natural teeth during implant placement is very low. Even in cases with insufficient bone volume, the possibility of inducing bone dehiscence or fenestration is decreased substantially. In addition, they allow implant placement immediately after extraction, shortening the edentulous period. Implant microstructure depends on the method of implant surface treatment. Albrektsson et al.1) listed six factors influencing the integration with bone, of which the surface property was the major factor influencing osseointegration. Numerous studies have examined bone healing for implants with diverse surfaces. The roughness of the implant surface increases the surface of the implant adjacent to bone, cell attachment to the implant surface, the volume of osteoid present on the implant surface, and the mechanical and biological reaction between the implant and adjacent bone.2) Buser et al.3) found a correlation between the roughness of the implant surface and the osseointegration. One method of altering the implant surface involves treatment with resorbable blast media (RBM), a biocompatible hydroxyapatite or oxidized titanium that avoids the shortcomings of sandblasting methods that may leave oxidized aluminum and other residues after the treatment,

Restoration of a partial edentulous ridge with a Dentis implant: A case report ď˝&#x153;

201

which may induce nerve injury or impede osseointegration. A roughened surface has a better effect on osseointegration than a smooth one.4) The maximal stress in implants is concentrated in the crestal region where the contact between the bone and implant is initiated. 5,6) Norton7) reported rapid bone resorption to the first screw with the Branemark implant, which has a dental crown with a smooth slope, while the Astra Tech Single Tooth Implant, which has a rough surface resulting from Tioblastâ&#x201E;˘ treatments and microthreadâ&#x201E;˘, maintained very stable bone levels. This shows the importance of the implant surface pattern on maintaining the alveolar crest.

IV. Conclusion Although implant treatment methods have numerous advantages compared to previous tooth restoration methods, implants are often refused because of the high costs and long restoration period. Therefore, numerous ways to decrease the cost or time have been developed. In this patient, seven Korean Dentis implants were placed in the maxilla and mandible simultaneously to shorten the treatment period; the surgery was performed relatively easily, and good early osseointegration was obtained for all seven implants. Continuous follow-up is required to obtain clinical information on the success rates, supplemented by objective information, such as radiological and histological evaluations, to evaluate the long-term safety of Korean Dentis implant products.

References 1. Albrektsson T, Branemark PI, Hansson HA, et al. Osseointegrated titanium implants. Requirements for ensuring a long-lasting, direct bone-to-implant anchorage in man. Acta Orthop Scand 1981;52:155-170. 2. Cooper LF. A role for surface topography in creating and maintaining bone at titanium endosseous implants. J Prosthet Dent 2000;84:522-534. 3. Buser D, Schenk RK, Steinemann S, et al. Influence of surface characteristics on bone integration of titanium implants. A histomorphometric study in miniature pigs. J Biomed Mater Res 1991;25:889-902. 4. Piattelli M, Scarano A, Paolantonio M, et al. Bone response to machined and resorbable blast material titanium implants: an experimental study in rabbits. J Oral Implantol 2002;28:28. 5. Kitoh M, Matsuhsita Y, Yamaue S, Ikeda H, Suetsugu T. The stress distribution of the hydroxyapatite implant under the vertical load by the two-dimensional finite element method. J Oral Implantol 1988;14:65-71. 6. Meijer HJ, Starmans FJ, Steen WH, et al. A three-dimensional, finite-element analysis of bone around dental implants in an edentulous human mandible. Arch Oral Biol 1993;38:491496. 7. Norton MR. Marginal bone levels at single tooth implants with a conical fixture design. The influence of surface macro- and microstructure. Clin Oral Implants Res 1998;9:91-99.

202

Effect of vertical distraction osteogenesis using a nitrified distractor on the osseointegration of Dentis implants Part

Abstract This study evaluated the effect of using a nitrified vertical distractor on osseointegration after implantation. Four adult mongrel dogs, weighing 9-10 kg, were used in this study. The lower premolars were extracted and vertical distraction was performed after 10 weeks using eight distraction devices (left, 4 titanium; right, 4 nitrified). A 7-day latency period was allowed before distraction was begun. The distraction device was activated at a rate of 0.5 mm twice/day for 5 days. After completing distraction, the device was removed after a retention period of 6 weeks and 24 Dentis implants were installed. The dogs were sacrificed after 4 or 8 weeks. Histological examinations were performed. Direct bone contact was achieved and there were no significant differences between the control and experimental groups in the implantation area. The results suggest that the nitrified distraction device has potential for use in augmentation of the atrophic edentulous ridge. Published Articles Effect of vertical distraction osteogenesis using a nitrified distractor on the osseointegration of Dentis implants

Key words : vertical distraction osteogenesis; nitrified distractor; implants

Effect of vertical distraction osteogenesis using a nitrified distractor on the osseointegration of Dentis implants ď˝&#x153;203

INTRODUCTION For successful implant placement, the appropriate height and width of bone are required. To place an implant in alveolar bone that has atrophied severely or been lost due to trauma, tumors, etc., bone grafting or guided bone regeneration (GRB) using bone substitutes are widely used. However, such techniques require the formation of additional soft tissue flaps since the soft tissues are usually insufficient, and the volume of alveolar bone that can be augmented is limited. Recently, the vertical distraction of alveolar bone has been developed as a method to replace alveolar bone augmentation, and good clinical results have been reported. The vertical distraction of bone requires an osteotomy or decortication in the area to be distracted, followed by the gradual separation of the bone fragments to induce the generation of new bone between the bone surfaces where blood is supplied, which achieves bone distraction and remodeling. 1) Snyder et al.2) applied the method to the distraction of canine mandibular bone. Regarding the augmentation of alveolar bone subject to bone distraction, Chin and Toth3) reported a method to augment the alveolar bone by performing a segmental osteotomy on mandibular anterior teeth with severe involution and, subsequently, inserting a thread pin directly in the alveolar area. The use of a titanium alloy distractor without a tin coating has numerous advantages, and has long been widely used. Its advantages include its biocompatibility, affinity to fibroblasts and facilitating their attachment, ability to reduce bacterial growth, and resistance to corrosion and abrasion.4) Given these advantages, numerous studies have examined other in vivo implants or surgical instruments. Nonetheless, few studies have examined bone distraction equipment. This study evaluated osseointegration and bone tissues histologically and histomorphologically, and the difference in the outcomes of vertical distractors with different surface treatments.

MATERIALS AND METHODS Materials Experiment animals The study was performed on four healthy 12-month-old dogs weighing 9-10 kg, raised under identical conditions. Implants Twenty-four RBM surface Dentis implants (Dentis, Daegu, Korea), 12 mm in length, and 3.75 mm in diameter were used. Distractors Four titanium vertical distractors and four nitrified titanium vertical distractors prepared in our laboratory were used. Experimental methods The study groups are outlined in Table I and the experimental procedure is outlined in the flowchart in Table II.

204

Table I. Study Groups Groups Control

Group 1 Group 2

Weeks

No. of implants

Distractor surface

Total distraction (mm)

Rate of distraction

Titanium

0.5 mm twice a day

Titanium

0.5 mm twice a day

Titanium nitride

0.5 mm twice a day

Titanium nitride

0.5 mm twice a day

Table II. Protocol

extraction P1-P4 of Mandible 10 weeks vertical distraction device fixation, 7 days latency period, 5 days distraction period (0.5 mm twice/day) 6 weeks device removal and implant installation 4 or 8 weeks sacrifice

Anesthesia Systemic anesthesia was induced with the intramuscular injection of 2 cc each of xylazine (Rompun, Bayer Vetchem-Korea) and ketamine (Ketara, Yoohan Yanghang) in the quadriceps. To prevent hemorrhage and pain, the extraction sites were infiltrated with 2% lidocaine. Extraction From each adult dog, the 1 st to 4th mandibular premolars were extracted, and a 10-week healing period was allowed. In all groups, to prevent infection after the extraction, distraction, and Dentis implant placement, 2 cc of gentamicin were injected daily for 5 days. Installing the distractor A conventional alveolar crestal incision was made. A full-thickness buccal flap was reflected over an area sufficient for the osteotomy. With a reciprocating saw, while protecting the buccal mucosa, a 20 Ă&#x2014; 10 mm osteotomy was made. The titanium surface equipment was installed in the left mandible of each dog (experimental group 1), and the nitrified titanium vertical distractor was installed on the right side (experimental group 2). To verify the operation of the vertical alveolar distractor, it was distracted and then returned to its original position. Then, the wound was sutured.

Effect of vertical distraction osteogenesis using a nitrified distractor on the osseointegration of Dentis implants ď˝&#x153;205

Part

Bone distraction While waiting for the soft tissues to heal, bone distraction was performed after a 7-day latency period at a rate of 2 rotations per day (0.5 mm per rotation, morning and evening) for 5 days, for a total of 5 mm. After the distraction was complete, a 6-week consolidation period was allowed in all cases. Removal of bone distractor and Dentis implant placement Six weeks after surgery, the vertical bone distractor was removed and Dentis implants were placed simultaneously using a submerged method. For each animal, two implants were placed in the distracted area (experiment group), one in the adjacent area (control group) for three implants on each side of the mandible or six implants per animal, and a total of 24 Dentis implants. Sacrifice At 4 and 8 weeks after implant placement, animals were sacrificed, and the implanted mandible was resected for tissue harvest. Experiment evaluation Four and 8 weeks after Dentis implant placement, the distracted area and bone in the vicinity of the Dentis implants were examined. The Dentis implant samples were fixed in 70% alcohol for 6 days, dehydrated through an alcohol series, and embedded in glycolmethacrylate resin (Spurr low-viscosity embedding media, Polyscience, Harrington, PA, USA). Polymerized samples were sectioned using a high-precision diamond disc (low-speed diamond wheel saw 650, SBT, San Clemente, CA, USA) along the long axis in 200-?m thicknesses. Then, using a lapping and polishing machine (OMNILAP 2000, SBT, San Clemente, CA, USA), abraded to 30-㎛ thicknesses. One slide was prepared per implant, stained with Villanueva osteochrome bone stain (San Clemente, CA, USA), and observed under a light microscope (Olympus BX50, Tokyo, Japan). For the histomorphometric evaluation, the percent of new peri-implant bone formation (NBFR) within the implant screws was calculated using the following formula: NBFR (%) = (New formed bone / Area outside the implant thread) × 100 The calculated results were analyzed statistically. Statistical analysis The filling rate of the Dentis implants and the amount of bone were analyzed using one-way analysis of variance (ANOVA) using SPSS ver. 12. In addition, Scheff?’s test was used for inter-group comparisons. P < 0.05 was considered statistically significant.

RESULTS At the time of sacrifice, none of the 24 Dentis implants had moved, there was no sign of infection or inflammation. The implant success rate was 100% in the control and experiment groups. Histomorphometric results In the experimental and control groups, the new bone filling rate was measured after 4 and 8 weeks, and the results are shown in Table III. Histologically, the bone tissues appeared normal and did not differ at the sites of distraction. Osseointegration was observed in all groups (Figs. 1 and 2). The rate of new bone filling within the implant screws did not differ significantly between the control and experimental groups (p=0.060 and p=0.191 at 4 and 8 weeks, respectively, ANOVA).

206

Table III. Bone to Metal Contact Rate (%) at 4 and 8 Weeks Given As The Mean±SD 4 weeks

8 weeks

Control

57.00±1.90

71.74±1.10

Group 1

53.52±1.68

69.76±1.32

Group 2

55.51±1.70

70.65±1.72

Total

55.34±2.18

70.72±1.52

* statistically significant difference p<0.05.

Fig. 1. Histologic findings in the control group. Newly formed bone was apparent within the threads of the implant surface, and direct bone contact with the implant surface was seen. Villanueva osteochrome bone stain, ×40.

Fig. 2. Histologic findings in the experimental group. Newly formed bone was observed at the distracted site and adjacent to the implant, and direct bone contact was seen. Villanueva osteochrome bone stain, ×40.

DISCUSSION Distraction osteogenesis is a technique that induces bone generation via the so-called “tension-stress effect”through the gradual distraction of the bone fragments. 5~8) Ilizarov5,6) developed a double ring-type distractor for lengthening the ilium and obtained good clinical results; he also explained the theoretical background experimentally, and began to draw attention to the technique. Chin and Toth3) reported successful alveolar bone distraction in the mandibular anterior tooth area with the application of transgingival screws. Simion et al.8) obtained an average of 3.5 mm of osteogenesis using guided bone regeneration. In this study, with the application of vertical distraction, 5 mm of osteogenesis was obtained. Distraction osteogenesis requires an osteotomy to divide the bone in two, a latency period after the osteotomy before applying distraction, which places traction on the fibrous callus, and a consolidation period once the traction force is terminated until the bone distractor is removed. For successful distraction osteogenesis, the blood supply to the bone fragments plays an important role. Ilizarov6,7) reported that in the ilium, the blood circulation within the bone marrow is essential for the regeneration of bone after distraction, and the occurrence of osteogenesis in the distraction area is dependent on the stability at the time of osteotomy and the amount of injury to the bone marrow, periosteum, and nutritional blood vessels, and recommended performing a cortical osteotomy. In this study, the buccal periosteum was

Effect of vertical distraction osteogenesis using a nitrified distractor on the osseointegration of Dentis implants ｜207

Part

dissected to the mandibular margin, and the osteotomy was performed carefully so as not to damage the periosteum in the buccal area. This allowed callus formation, and the ossification process progressed after distraction without problems. Periosteal reaction and abundant new bone formation on the buccal side were observed after distraction. Distraction osteogenesis allows the simultaneous augmentation of soft and hard tissues and is considered a very useful technique. Nonetheless, the stability of the distracted bone is controversial. Saulacic et al.9) reported that to allow for relapse during the consolidation period, slight overcorrection is useful, and for alveolar bone, 25% of the distraction amount or approximately 1-3 mm may be required. Rachmiel et al.10) reported that distraction osteogenesis induces skeletal distraction and the augmentation of soft tissues, and bone trabeculae was observed 6 weeks after the completion of distraction osteogenesis; to prevent relapse, a long consolidation period is required. Generally, consolidation periods of 6-8 weeks for the mandible and 2-3 months for the maxilla are appropriate.11) We found that a 6-week consolidation period resulted in sufficient bone for implant placement. Several studies have examined the use of nitrified surface treatment for other biological implants and surgical instruments.12-14) Huang15 have reported that a nitrified surface exposed to artificial saliva showed excellent resistance to erosion, and that more cells adhered to the nitrified surface. Scarano et al. 4) reported that nitrified surface treatment reduced the attachment of bacteria, reducing soft tissue infection near the implants. In this study, the amount of new bone formation and bone attachment was not significantly different with the nitrified titanium vertical distractor. Nevertheless, we confirmed that vertical distraction osteogenesis is a useful technique for the placement of implants in atrophied alveolar bone. A distractor with a nitrified surface is better in terms of the surface hardness and the prevention of erosion, and should be more effective in certain environments. Future studies should evaluate the hardness of the equipment surface, etc.

CONCLUSIONS Alveolar bone was augmented using distraction osteogenesis and good results were obtained with Dentis implants. The implant success rate was 100% in all of the study groups. There was no significant difference between the distractors with the nitrified surface and those made of titanium alloy. In general, distraction is a useful technique for vertical bone augmentation.

References 1. Costantino PD, Friedman CD. Distraction osteogenesis. Applications for mandibular regrowth. Otolaryngol Clinics North Am 1991;24:1433-1443. 2. Snyder CC, Levine GA, Swanson HM, Browne EZ Jr. Mandibular lengthening by gradual distraction. Preliminary report. Plast Reconstr Surg 1973;51:506-508. 3. Chin M, Toth BA. Distraction osteogenesis in maxillofacial surgery using internal devices: review of five cases. J Oral Maxillofac Surg 1996;54:45-53.

208

4. Scarano A, Piattelli M, Vrespa G, Caputi S, Piattelli A. Bacterial adhesion on titanium nitride-coated and uncoated implants: an in vivo human study. J Oral Implantol 2003;29:8085. 5. Ilizarov GA. The tension-stress effect on the genesis and growth of tissues. Part I. The influence of stability of fixation and soft-tissue preservation. Clin Orthop Relat Res 1989;238:249-281. 6. Ilizarov GA. The tension-stress effect on the genesis and growth of tissues: Part II. The influence of the rate and frequency of distraction. Clin Orthop Relat Res 1989;239:263-285. 7. Ilizarov GA. The possibilities offered by our method for lengthening various segments in upper and lower limbs. Basic Life Sci 1988;48:323-324. 8. Simion M, Trisi P, Piattelli A. Vertical ridge augmentation using a membrane technique associated with osseointegrated implants. Int J Periodontics Restorative Dent 1994;14:496-511. 9. Saulacic N, Somoza-Martin M, Gandara-Vila P, Garcia-Garcia A. Relapse in alveolar distraction osteogenesis: an indication for overcorrection. J Oral Maxillofac Surg 2005;63:978-981. 10. Rachmiel A, Aizenbud D, Peled M. Long-term results in maxillary deficiency using intraoral devices. Int J Oral Maxillofac Surg 2005;34:473-479. 11. Swennen G, Schliephake H, Dempf R, Schierle H, Malevez C. Craniofacial distraction osteogenesis: a review of the literature: Part 1: clinical studies. Int J Oral Maxillofac Surg 2001;30:89-103. 12. Goldberg JR, Gilbert JL. The electrochemical and mechanical behavior of passivated and TiN/AlN-coated CoCrMo and Ti6Al4V alloys. Biomaterials 2004;25:851-864. 13. Cyster LA, Parker KG, Parker TL, Grant DM. The effect of surface chemistry and nanotopography of titanium nitride (TiN) films on primary hippocampal neurones. Biomaterials 2004;25:97-107. 14. Tamura Y, Yokoyama A, Watari F, Kawasaki T. Surface properties and biocompatibility of nitrided titanium for abrasion resistant implant materials. Dent Mater J 2002;21:355-372. 15. Huang HH. Surface characterizations and corrosion resistance of nickel-titanium orthodontic archwires in artificial saliva of various degrees of acidity. J Biomed Mater Res A 2005;74:629-639.

Effect of vertical distraction osteogenesis using a nitrified distractor on the osseointegration of Dentis implants ď˝&#x153;209

Part

INDEX... Abutment System Selection Guide / 14, 100 Angled Abutment / 106, 115, 122 Cemented Abutment / 120 Cemented Abutment System / 66 Characteristics of Dentis Implant / 22 Cleaning System / 20 Collatape / 148 Combined KIT / 86 Complete osteotomy / 148 Components of Dentis Products / 32 Couple Abutment / 113 Couple Abutment System / 54 Dentis Abutment System / 26 Dentis Implant System Selection Guide / 12 Dentis Surgical Kit / 84 Distraction osteogenesis / 207 Drilling Sequences : External Type / 95 Drilling Sequences : Internal and Submerged Type / 92 Effect of vertical distraction osteogenesis using a nitrified distractor on the osseointegration of Dentis implants / 203 Estheticone Abutment / 123 Estheticone Abutment System / 70 External Abutment System / 29 External Fixture / 64, 87 External Implant System Flow / 64 Fixture System Selection Guide / 12 Free Abutment

/ 104, 112

Gold UCLA Abutment / 108, 114, 121 Guided bone regeneration / 173 Horizontal alveolar bone distraction using a distractor / 182 Implant placement using the SAVE implant / 191 Impression Taking : External Type / 118 Impression Taking : Internal Type / 102 Impression Taking : Submerged Type / 111 InOcta Abutment / 105 InOcta Abutment System / 38 Internal Abutment System / 26 Internal Implant System Flow / 32 Internal/Submerged Fixture / 87

210

Mandibular anterior teeth / 158 Mandibular posterior teeth / 162, 165, 167, 170 Maxillary anterior teeth / 126 Maxillary posterior teeth

/ 152, 155

Mount Abutment / 119 Nd:YAG laser / 177 Nitrified distractor / 203 Octa Abutment / 109, 116 Octa Abutment System / 42 O-Ring Abutment / 110, 117, 118 O-Ring Abutment System / 46, 62, 74 Overdenture / 176, 179 PROKIT / 89 PRP / 148 RBM(Resorbable Blast Media) / 19 Restoration of a partial edentulous ridge with a Dentis implant: A case report / 197 SAVE fixture / 192 SAVE Internal / 13 SAVE Internal Fixture / 78 SAVE Internal Implant System Flow / 78 SAVE Submerged / 13 SAVE Submerged Fixture / 76 SAVE Submerged Implant System Flow / 76 SAVE KIT / 88 Sinus lift / 130, 134, 138, 141, 144, 147, 150 Sole Abutment / 111 Sole Abutment System / 50 Solid Abutment / 102 Solid Abutment System / 34 Submerged Abutment System / 28 Submerged Fixture / 48 Submerged Implant System Flow / 48 Sub-Octa Abutment System / 58 Surface Treatment / 18 Surgical Kit and Tool / 92 SynOcta Abutment / 107 Tension-stress effect / 207 Vertical distraction osteogenesis / 203

211

212

213

Copyright â&#x201C;&#x2019; 2009 by The JeeSung Publishing Company All rights reserved. No part of this publication may be reproduced or transmitted by any means, electronic, mechanical, or otherwise, including photocopying and recording, or by any information storage or retrieval system, without permission-in-writing from the publisher. ISBN 978-89-8484-177-2 Printed in Korea 245-21, Neung-Dong, Gwangjin-Gu, Seoul 143-848 / Korea

Su Gwan Kim, D.D.S., Ph.D

DENTIS IMPLANT Book Design : Kyung Soon Jang