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全顎植體固定式贋復:治療思路與文獻回顧
Implant-Supported Full-arch Fixed Rehabilitation: Treatment Planning and Literature Review
響,仍待觀察。(Fig.1) Fig.1 Square 及 taper arch form 可能會出現不同的 A-P spread
Interocclusal Space 上下顎贋復空間過多與過少皆會造成問題。Interocclusal space 的估量是指從
對咬牙之咬合面到 Implant platform(或者 bone crest)的空間,根據 Phillips 1(1995)的意見,Fixed-detachable(hybrid denture)所需的空間為 18mm = tissue depth (3mm) +hygiene (2mm) + framework (8mm) + pink acrylic (2mm) + denture tooth (3mm) 其中 Hygiene space 應該可以節省至 1mm(使用牙間刷清潔)或者 0mm(牙線清潔)。 Framework 之設計與 denture tooth 所需之空間也可能不同。LoCascio and Salinas 2(1997) 則是估算為 15mm。 相較於 Bar and clip overdenture 所需空間 14mm=tissue depth (3mm) + hygiene (1.5 mm) + bar (4.5mm) + acrylic and housing (2mm) + denture tooth (3mm) 。 以及 Implant Fixed Partial Denture (PFM)的 9-12mm=tissue depth (3mm) + abutment (4-7mm) + occlusal restoration space (2mm)。可知 Fixed detachable prostheses 空間需求相對較多。甚至如果製作 Two-piece superstructure for fixed detachable (Wee3 1997)可能會再多出 2mm( for fixed frame)的需求。
另一方面,當嚴重的殘脊吸收造成 Interocclusal space 相當多時,
Crown-implant ratio(C/I)會變得很大。儘管對於多大的 C/I 會影響 marginal bone level 目前沒有定輪,Malchiodi et al4(COIR 2013)指出 Critical threshold of crown-implant ratio 介於 3.1-3.4 之間。超過這個數值容易造成過度的邊緣骨喪
失。舉例來說,如果某下顎後牙植體的長度在 8-12mm 之間,則合理的贋復空間
應該在 24-36mm。這樣的數值看起來似乎很安全,但只代表著邊緣骨喪失的臨
界值,不能代表沒有贋復方面的併發症。另一篇 2014 年的 systematic review(Garaicoa-Pazmiño et al5)則指出 C/I ratio 顯著地對於 marginal bone level 有影響。過大的贋復空間和 C/I ratio 也意味著咬合面距離 Implant platform 增加,
法,在適當的選擇患者條件之下,All-on-four protocol 是一個可以接受的選項。 Fig.3 Implant number and design for full-arch implant FPD
Fig.4 Mandibular flexure
Fig.5 Milled bar splinting mandibular implants may also be affected by mandibular flexure
Fig.6 All-on-four technique (Butura et al, 2011)
Patient Factors 患者本身的因素也是決定治療計畫的關鍵,例如:
• Specific esthetic expectation • Lip line • The type and amount of hard/soft tissue defect • Parafunction • Heavy smokers • Bisphosphonate medication • Oral hygiene
另外也有其他考量會影響治療計畫,例如:
• Implant system selection: bone vs. tissue level • Implant B-L/M-D position and angulations • Framework design and passive fit • Occlusal scheme • Restorative materials: resin vs. ceramometal • Attachment systems • Repair and maintenance • Immediate provisionalization?
Restorative-driven (or esthetic-driven) implant placement 的概念拿出來講。 這樣實際的臨床情況其實恰恰好反映了一個重要的問題,如果 surgical guide不夠精準(To be dead on!),那麼反而會造成誤差,手術醫師沒有辦法完全的依賴
而必須當場作調整。一個準確而實用的手術定位板,不僅只是參考贋復方面的需
求,應該要考量手術完成的困難程度。齒槽骨的寬度與高度僅管可以利用 GBR或 Bone block 去作增加,但是過大角度的植體或是無法取得 Primary stability,都可能造成補骨程序困難。因此設計手術定位板的醫師應當充分理解植體手術步
驟與患者狀況,利用 X 光片及 CT 反覆確認與更正植體位置。如果沒有充分把握
確切位置,可以考慮使用 Non-restricted guide(e.g. vacuum formed matrix),界定植
體合理的範圍,讓手術醫師當場決定。 植體置入前診斷與前置作業參考流程: 1. Diagnostic setup/waxup 2. Esthetic try-in 3. Occlusal scheme and interocclusal space evaluation 4. Radiographic guide duplicating the waxup 5. Bone augmentation before implant placement 6. Re-evaluation of bone volume 7. Surgical guide/template
Fig.12A-D Implant surgery with use of surgical guide
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Fig.13A&B Implant healing and final impression
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Fig.14A-D Provisional FPD with pink acrylic gingival
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Fig.15A-D Framework try-in
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Fig.16A-F Final implant abutment and prostheses
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F. Reference
1. Phillips K, Wong KM. Vertical space requirement for the fixed-detachable, implant-supported prosthesis. Compend Contin Edu Dent 2002 Aug 23(8):750-6
2. LoCascio SJ, Salinas TJ. Rehabilitation of an edentulous mandible with an implant supported prosthesis. Pract Periodontic Aesthet Dent1997; 9:357-70
3. Golden et al. Fabrication of a two-piece superstructure for a fixed detachable implant supported mandibular complete denture. J Prosthet Dent 2000;84:205-9
4. Malchiodi L, Cucchi A, Ghensi P, Consonni D, Nocini PF. Influence of crown-implant ratio on implant success rates and crestal bone levels: a 36-month follow-up prospective study. Clin Oral Implants Res. 2014 Feb;25(2):240-51
5. Garaicoa-Pazmiño C, Suarez F, Monje A, Catena A, Ortega-Oller I, Galindo-Moreno P, Wang HL. Influence of Crown-Implant Ratio Upon Marginal Bone Loss. A Systematic Review. J Periodontol. 2014 Jan 20 Epub ahead of print.
6. de Moraes SLD, Verri FP, Santiago JF, Almeida DA, Mello CC, Pellizzer EP. A 3-D Finite Element Study of the Influence of Crown-Implant Ratio on Stress DistributionBraz. Dent. J. vol.24 no.6 Ribeirão Preto Nov./Dec. 2013
7. Butura CC, Galindo DF, Jensen OT. Mandibular all-on-four therapy using angled implants: a three-year clinical study of 857 implants in 219 jaws. Dent Clin North Am. 2011 Oct;55(4):795-811.
8. Balshi TJ, Wolfinger GJ, Slauch RW, Balshi SF. Retrospective Analysis of 800 Brånemark System Implants Following the All-on-FourTM Protocol J of Prosthodont 2013Jul 25:1-6 [Epub ahead of print]