
老何的全口重建課程前導影片-3 (English-key-points)
講述的是全口重建中「有計畫的咬合」設計流程。影片闡述咬合設計並非單純調整,而是從 整體評估 開始,考量 咬合支撐(包含後牙雙邊至少兩對支撐點)、咬合空間(前牙、後牙垂直及水平空間,需考量美觀與功能) 等大方向,再逐步細化到 咬合面設計(前、後牙導引) 及 咬合調整(不同假牙類型需考量不同因素,例如活動假牙與固定假牙)。最後,影片說明如何利用 傳統或數位方式進行咬合模型複製,以確保重建的咬合與患者口腔狀況相符。 整個過程強調 系統性規劃與反覆驗證,而非僅著重於局部細節。
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有計畫的咬合學影片內容介紹
這個影片主要在講解「有計畫的咬合學」,從個案評估、診斷蠟型、臨時假牙調整到正式假牙製作,每個環節都息息相關。影片內容可以分成以下幾個部分:
一、咬合計畫的整體架構
- 咬合計畫的考量,從個案評估就開始了,診斷蠟型階段開始設計咬合,臨時假牙調整階段驗證咬合,最後轉移到正式假牙製作。
- 咬合學的應用,涵蓋了美觀、功能和生理結構,並以咬合學原理去理解。
- 咬合計畫如同蓋房子,需要先考慮咬合力分配和咬合支撐(如同房子的柱子),接著才考慮咬合面的細節(如同房子的裝潢)。
二、咬合支撐和空間
- 咬合支撐:
- 雙邊後牙都要有支撐,至少兩對以上,才能確保咬合穩定。
- 即使是縮短的牙弓 (shorten dental arch),只要兩邊後牙都有成對咬合且數量足夠,也能維持穩定。
- 咬合空間:
- 除了後牙的水平和垂直高度,也要考慮前後牙的關係,以及前牙露出程度與嘴唇的關係(美觀)。
- 自然牙需要考量牙齦、Abutment和 Focation 等因素;植牙則需要考量骨頭、牙齦和兩個Arch之間的空間。
- 不同種類的植體 (B, locator, fix) 所需的空間也不同。
- 咬合平面的確定,需要反覆確認各種因素,並找到一個共同解,兼顧功能和美觀。
- 沒有牙齒參考時,可以使用常用的 campus line 來參考。
三、咬合面的設計
- 牙齒互相接觸時,有一些前後的限制因素:
- 後牙的結構,例如關節或前牙。
- 前牙互相之間的角度,也就是後方引導和前方引導。
- 後方引導主要受生理結構限制,而前方引導則由牙齒控制,在全口重建時有較大的自由度,但也需要更多猜測和測試。
- 設計咬合面時,可以使用 JN 提出的三個 P:
- Position:關節的位置。
- Place:咬合面要放在哪裡。
- Pathway:路徑引導。
四、關節和肌肉
- 合理使用下顎關節,開合動作類似同軸運動,但並非完全同軸。
- 肌肉的緊繃或鬆弛會影響下顎位置,因此需要找到放鬆的下顎位置(CR)。
- CR 的取得方法很多,對應到不同的假牙製作方式,選擇方法的重點在於:
- 簡單確認可用徒手方法。
- Fix 假牙可用Licia jig。
- 活動假牙可用 checkbite 或 Gothic-arch,利用中心受力點更容易抓到正確位置。
- CR 是全口重建時的一個原點,不同方法取得的 CR 位置會不同,因此在同一個 case 中要使用相同方法,才能減少誤差。
- 隨著 case 的進展,CR 取得方式可能會改變,例如一開始用活動假牙的方式,到最後用固定假牙的方式。
五、路徑引導
- 後方路徑引導:
- 可以用下顎追蹤方式得到關節移動軌跡。
- 也可以用前突bite取得關節往前滑移的角度。
- 局部補綴時,可以用下顎滑移軌跡製作,只要不產生干擾即可。
- 前方路徑引導:
- 需符合正常的比例,並與後方引導產生和諧的比例。
- 正常的引導角度從 60 度到 80 度都有,需要找到正確比例並兼顧美觀。
- 通常前方引導會比後方引導再大一點點。
六、咬合調整
- 咬合調整要先考慮假牙種類:
- 活動假牙的支撐是軟組織,因此咬合設定必須左右平衡 (balancing occlusion),前後也要平衡。
- 固定式假牙則需要注意路徑的平順,避免產生震動或干擾。
- 任何咬合方式都存在牙齒接觸和空中揮舞的部分,也就是 guidance,要像飛機降落一樣平順,避免撞擊。
- 不同材質的牙齒受力程度不同,需要考量如何取得平衡,例如自然牙和植牙之間的差異,以及自然牙本身的亞洲問題。
- 牙齒擺放位置會影響臉頰和舌頭的空間,通常要放到中力的位置 (neutral zone),但有時需要調整才能兼顧咬合和舒適度。
- 長期缺牙的患者,在裝上假牙後,需要特別注意軟組織的適應和調整。
- 舌頭可能會取代牙齒的功能,在全口重建後,需要驗證舌頭是否能與假牙和平共處。
七、複製
- 現代的複製工作可以用數位掃描完成,但需要了解傳統方法 (cross mounting) 的概念,才能正確掃描對位。
- 數位掃描前,需要收集以下資訊:
- 全形態臨時假牙。
- Abutment 的全形態。
- 臨時假牙本身。
- 傳統的 cross mounting 需要利用 jig 局部抽換臨時假牙和 bite,將不同口腔狀況的假牙,精確地固定在咬合器上。
- 數位掃描則是以口掃取代 checkbite,只要確定哪些地方可以重疊並得到穩定咬合,就可以掃描對位。
總結
影片詳細介紹了有計畫的咬合學,從整體架構到細節調整,涵蓋了各個環節,並強調了咬合支撐、空間、咬合面設計、關節肌肉、路徑引導、咬合調整和複製等重要概念。
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Introduction to Planned Occlusion
This video focuses on “planned occlusion,” explaining the interconnected steps from case evaluation, diagnostic wax-up, temporary denture adjustments, to final prosthetic fabrication. The content can be divided into the following sections:
I. Overall Structure of an Occlusal Plan
• Considerations for Occlusal Planning:
• Begins with case evaluation, followed by designing occlusion during the diagnostic wax-up stage, verifying occlusion during temporary denture adjustments, and finally transferring it to the fabrication of the final prosthetic.
• Application of Occlusion:
• Covers aesthetics, function, and physiological structure, understanding these through the principles of occlusion.
• Occlusal Planning Analogy:
• Comparable to building a house: first ensuring occlusal force distribution and support (like the house’s pillars), then focusing on occlusal surface details (like interior decoration).
II. Occlusal Support and Space
• Occlusal Support:
• Stable occlusion requires bilateral posterior support with at least two pairs of teeth on each side.
• Even in shortened dental arches, as long as there are sufficient paired posterior teeth on both sides, stability can be maintained.
• Occlusal Space:
• Considerations include the horizontal and vertical dimensions of posterior teeth, the relationship between anterior and posterior teeth, and the relationship between anterior tooth exposure and lip position (aesthetics).
• For natural teeth, factors such as gingiva, abutments, and furcation must be considered; for implants, factors such as bone, gingiva, and inter-arch space are critical.
• Different types of implants (e.g., bar, locator, fixed) require different amounts of space.
• Determining the Occlusal Plane:
• Requires repeated verification of various factors to find a balance between function and aesthetics.
• When no teeth are present for reference, common guides such as the camper’s line can be used.
III. Occlusal Surface Design
• Contact Limitations:
• Posterior occlusion is influenced by structures like the joints and anterior teeth.
• Anterior tooth angles determine posterior and anterior guidance.
• Designing the Occlusal Surface:
• Dr. JN’s “Three P’s” can guide the design:
1. Position: Joint position.
2. Place: Where to place the occlusal surface.
3. Pathway: The path of guidance.
IV. Joints and Muscles
• Jaw Joint Dynamics:
• Mandibular motion resembles coaxial movement but is not entirely so.
• Muscle Relaxation and Jaw Position:
• A relaxed mandibular position (centric relation, CR) is critical, influenced by muscle tension or relaxation.
• Methods to Obtain CR:
• Different techniques correspond to various prosthetic types:
• Manual methods for simple verification.
• Licia jig for fixed prosthetics.
• Checkbite or Gothic arch tracers for removable prosthetics, making it easier to identify the central force point.
• CR serves as the origin in full-mouth reconstructions; the same method must be used throughout a case to minimize errors.
V. Pathway Guidance
• Posterior Pathway Guidance:
• Joint movement can be tracked using mandibular tracing or by capturing protrusive bites to determine the forward slide angle.
• Partial restorations can follow mandibular paths as long as they avoid interference.
• Anterior Pathway Guidance:
• Should align proportionally with posterior guidance, balancing function and aesthetics.
• Normal guidance angles range from 60 to 80 degrees, with anterior guidance typically slightly larger than posterior.
VI. Occlusal Adjustments
• Consider the Type of Prosthetic:
• For removable prosthetics, occlusion relies on soft tissue support, necessitating balanced occlusion both laterally and anteroposteriorly.
• Fixed prosthetics require smooth paths to avoid vibration or interference.
• Key Points in Adjustment:
• Contact and clearance areas (guidance) must resemble a plane’s smooth landing, avoiding impact.
• Different materials withstand forces differently, requiring adjustments to balance natural teeth and implants.
• Long-term edentulous patients need careful adaptation and adjustment of soft tissues after prosthetic placement.
• Tongue adaptation is also crucial, ensuring harmony between tongue function and the prosthetic.
VII. Replication
• Modern Digital Workflow:
• Digital scanning replaces traditional cross-mounting, requiring knowledge of traditional concepts for proper alignment.
• Prerequisites for digital scanning include:
• Complete temporary denture morphology.
• Full abutment morphology.
• Temporary dentures themselves.
• Traditional cross-mounting uses jigs for precise positioning on articulators, while digital scanning relies on stable overlapping points for alignment.
Summary
The video provides a comprehensive guide to planned occlusion, covering the overall structure and detailed adjustments. It emphasizes essential concepts such as occlusal support, space, occlusal surface design, joints and muscles, pathway guidance, occlusal adjustments, and replication.