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What is a dental crown? Can a missing tooth have a crown? First, is the root still there?

km 編輯部2026-08-13About 6 min read
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The everyday terms for a false-tooth “cap” usually mean a crown made by a dental technician and fitted over your own tooth. A crown needs a supporting structure. If the root remains, a crown may be the route; if the entire tooth and root are absent, a crown alone cannot be made, and bridge, implant-supported crown or removable-denture routes need separate assessment. This card explains crowns, indications, why a wholly missing tooth differs, and the three replacement routes. It lists no prices.

What is a dental crown? Can a missing tooth have a crown? First, is the root still there?

Direct answer: A crown fits over your own tooth and needs a supporting structure.[F13] If the root remains, a crown may be the route. If the whole tooth is absent, a crown alone cannot be made; bridge, implant or removable-denture options need to be assessed instead.[F8][F9]
Geographic scope: This guide is specific to Taiwan's healthcare system (National Health Insurance and Taiwan's Medical Care Act). Institutional, terminology and verification passages cite Taiwan law and authority-approved announcements; medical evidence cites international literature, separately tagged in the fact account. The official English text of Taiwan’s Medical Care Act is https://law.moj.gov.tw/ENG/LawClass/LawAll.aspx?pcode=L0020021 .

Scope of this card

This card explains what a crown is, how common names map to items, when a crown may be proposed and why an entirely missing tooth cannot receive only a crown. The full cost, material, ferrule and remaining-tooth-structure discussion is in the crown-cost card; fixed-prosthesis pathways and bridge costs are in the fixed-denture-cost card; orthodontic versus prosthetic uses of “braces” are in the terminology-disambiguation card.[F2]

Names and structure

Everyday language may say cap, crown, single-tooth cap, or “false tooth”. In the Taipei approved dental schedule, crown-class items include cast crowns, veneer cast crowns, porcelain-fused-to-metal crowns, all-ceramic crowns and therapeutic temporary crowns; all are charged per tooth.[F8] In the literature, a tooth-supported single crown is supported by one’s own tooth; an implant-supported single crown is a separate category.[F13][F20] Broad everyday naming is not an official classification, so ask the provider to state the diagnosis and treatment item clearly.[F2][F5]

A crown is a full-coverage fixed restoration. Remaining tooth tissue is shaped as a foundation; after an impression, a dental technician makes the crown and it is cemented or retained on that foundation.[F8][F13] If too little tooth structure remains, a post-and-core may support the crown. The Taipei schedule lists cast and prefabricated post-and-core items separately per post, therapeutic temporary crowns separately per tooth, and fixed-prosthesis cementation as another item.[F8][F10]

When might a crown be proposed?

Evidence strength differs by condition. In a 2024 systematic review and meta-analysis of cracked teeth, with 27 studies qualitatively analysed and 26 meta-analysed, vital cracked teeth restored directly without cuspal coverage had a risk ratio of 3.2 for pulpal complications (95% CI 1.51 to 6.82) and 8.1 for extraction (95% CI 1.05 to 62.5) compared with full-crown restoration. Root-filled cracked teeth without full crowns had 11.3-fold higher extraction risk. The review also said monitoring may be an option for cracked teeth without symptoms. These are observational findings for specified study populations; the wide interval means they cannot be read as “no crown means the tooth will be lost”.[F14][F5][F2]

After root-canal treatment, the eligible Cochrane randomised evidence was only 1 high-risk-of-bias trial, with no clear three-year difference in non-catastrophic restoration failure and very-low-certainty evidence; there is insufficient evidence to assess crown versus conventional filling effects.[F15] A 2024 systematic review and meta-analysis estimated survival of root-filled posterior teeth at 91% over 4 to 7 years and 87% over 8 to 20 years, and named remaining coronal tooth structure, ferrule, crown-to-root ratio, tooth type/location, periodontal disease, proximal contacts and cracks as tooth-related prognostic factors.[F16] A crown decision is therefore individual, not a universal rule.[F15][F16]

A full crown is not the only route. A 2024 systematic review found that full-cuspal-coverage onlays instead of full crowns may be favourable in the short to midterm for root-filled posterior teeth; applicability still needs assessment.[F26][F2]

A wholly missing tooth cannot have “only a crown”

If only the crown portion is broken or decayed but the root remains in the alveolar bone, that is not a wholly missing tooth; salvageability and any need for a post-and-core require examination.[F16][F17] This section concerns the absence of both crown and root. A crown needs a support: tooth-supported crowns rely on one’s own tooth, and implant-supported crowns on an implant.[F13][F20]

The Taiwan fee schedule uses separate item groups: crown items per tooth, adhesive bridges per set, removable partial dentures per arch and complete dentures per set.[F8][F9] Implant prosthetic treatment is separately listed and excludes special abutments and special-material fees. That supports a structural reading—prosthesis and abutment are separate components—not an official terminology definition.[F11][F2] For a missing tooth, the question is what will support it; the crown is the outer part.[F21][F2]

Three replacement routes

The figures below come from different systematic reviews with different populations, failure definitions and follow-up; they are not head-to-head rankings.[F2][F19][F20][F22]

  1. Bridge (fixed partial denture): adjacent teeth are prepared as abutments and a connected restoration crosses the gap. A 2026 systematic review and meta-analysis of 41 studies, 600 metal-ceramic and 1,532 all-ceramic restorations, reported five-year survival by material from 82.5% to 92.9%; metal-ceramic was 91.3%, and 71.0% of restorations were complication-free at five years. All-ceramic bridges had more marginal caries and loss of retention than metal-ceramic bridges. The trade-off is preparation of adjacent teeth that may otherwise be healthy.[F19][F2]
  2. Implant-supported crown: an implant replaces the root as the support, then a crown is screwed or cemented above it. The cited review reports favourable short-term survival and complication results, but annual ceramic chipping was significantly higher for veneered than monolithic crowns. Surgical conditions, bone quantity and cost structure are separate variables.[F20][F2]
  3. Removable denture: it is supported by remaining teeth and the denture-bearing tissues and can be removed. A 2025 systematic review and meta-analysis estimated 95.1% five-year survival for cast-clasp removable partial dentures; abutment teeth had a higher extraction risk after five years (OR 1.99, 95% CI 1.32 to 3.01).[F22] Whichever route is chosen, the supporting teeth need care.[F2]

Waiting, Taiwan’s system, and questions before treatment

An untreated gap can permit movement of opposing and neighbouring teeth. A prospective female cohort found a higher risk of overeruption of at least 2 mm for molars without an opposing tooth; the full interpretation is in the missing-molar card.[F23][F2]

Taiwan has no nationwide crown price list: Article 21 of Taiwan’s Medical Care Act assigns approval of fee standards to the municipality or county/city authority.[F4] Article 51, subparagraph 11, of Taiwan’s National Health Insurance Act lists dentures and related appliances outside coverage; other procedures in a course of care follow the Administration’s current announcements.[F7] Look for the fee schedule of the county/city health authority where care is received. Taiwan’s medical-device price-comparison site does not include dental categories.[F8][F12][F27] Private-insurance matters depend on the policy terms.

Ask: how much tooth structure and usable root remain; what is the reason for a crown and are there full-cuspal-coverage alternatives; are post-and-core or temporary crown separate items; if the tooth is wholly absent, what will each bridge, implant and removable-denture route involve; and do the treatment plan, quotation and receipt use matching item names? Article 81 of Taiwan’s Medical Care Act requires explanation of condition, treatment plan, procedures, medication, prognosis and possible adverse reactions.[F16][F17][F14][F15][F26][F8][F10][F19][F20][F22][F5]

Every clinical statement in this article is mapped line by line to its cited source (see the sources and evidence chain below). It has not been clinically reviewed by a licensed practitioner. This is health information, not individual advice; assessment by a clinician is required.

FAQ

Are “cap”, “crown” and “single-tooth cap” the same?
In most clinical usage they refer to a fixed crown over one tooth, but terms for braces can have a different meaning and must be separated first.[F2][F8]
被せ物、歯冠、1 本の被せ物は同じですか。 — 多くの診療文脈では 1 歯にかぶせる固定冠を指しますが、矯正装置の意味の語と混同しないよう先に分けます。[F2][F8]
Are “cap”, “crown” and “single-tooth cap” the same? — In most clinical usage they refer to a fixed crown over one tooth, but terms for braces can have a different meaning and must be separated first.[F2][F8]
Can a missing tooth have a crown?
Not a crown alone. Decide among bridge, implant or removable-denture support; the crown is the part over that support.[F13][F20][F8][F9][F21]
欠損歯に被せ物はできますか。 — 冠だけはできません。ブリッジ、インプラント、可撤性義歯のどれで支えるかを決め、冠は支えの上の部分です。[F13][F20][F8][F9][F21]
Can a missing tooth have a crown? — Not a crown alone. Decide among bridge, implant or removable-denture support; the crown is the part over that support.[F13][F20][F8][F9][F21]
If only a short root remnant remains, is it a wholly missing tooth?
No, but whether it can remain depends on tooth structure, ferrule, crown-to-root ratio and periodontal conditions, which require examination.[F16][F17][F5]
歯根が少し残る場合は完全欠損ですか。 — いいえ。保存の可否は残存歯質、フェルール、歯冠歯根比、歯周条件を診査して判断します。[F16][F17][F5]
If only a short root remnant remains, is it a wholly missing tooth? — No, but whether it can remain depends on tooth structure, ferrule, crown-to-root ratio and periodontal conditions, which require examination.[F16][F17][F5]
Is a crown always required after root-canal treatment?
No universal answer follows from the evidence. Randomised evidence is insufficient; cracked-tooth observational evidence and remaining-coronal-structure factors must be considered together.[F15][F14][F16]
根管治療後は必ず被せ物が必要ですか。 — 一律には言えません。ランダム化根拠は不足しており、亀裂歯の観察根拠と残存歯冠部歯質などを合わせて判断します。[F15][F14][F16]
Is a crown always required after root-canal treatment? — No universal answer follows from the evidence. Randomised evidence is insufficient; cracked-tooth observational evidence and remaining-coronal-structure factors must be considered together.[F15][F14][F16]
Is the part on top of an implant also called a cap?
Many people call it that in everyday speech; the formal term in the literature is an implant-supported single crown [F20]. The difference is not the crown itself but what supports it underneath — your own tooth root or an implant [F13][F20]. The official fee items also list the implant prosthetic procedure separately from crown items, and note that it does not include the abutment and similar components [F11]. So when you ask whether an implant "also needs a cap", the question to ask is how the prosthesis and the abutment are each accounted for in this particular plan [F2].
インプラントの上の部分も被せ物と呼びますか。 — 日常会話ではそう呼ぶ人が多いですが、文献での正式な呼称はインプラント支持単冠です [F20]。違いは冠そのものではなく、それを下で支えているのが自分の歯根かインプラントかという点です [F13][F20]。公的な料金項目でも、インプラント補綴の処置費は冠の項目と分けて掲げられ、アバットメント等の材料を含まないと注記されています [F11]。したがって「インプラントにも別に被せ物が要るのか」と尋ねるときに本当に確認すべきなのは、その治療計画で補綴物とアバットメントがそれぞれどう計上されているかです [F2]。
Is the part on top of an implant also called a cap? — Many people call it that in everyday speech; the formal term in the literature is an implant-supported single crown [F20]. The difference is not the crown itself but what supports it underneath — your own tooth root or an implant [F13][F20]. The official fee items also list the implant prosthetic procedure separately from crown items, and note that it does not include the abutment and similar components [F11]. So when you ask whether an implant "also needs a cap", the question to ask is how the prosthesis and the abutment are each accounted for in this particular plan [F2].

Medical notice　This article is provided for health education and medical information purposes. It is not a solicitation for medical services and does not constitute diagnosis or treatment advice. Actual treatment methods and outcomes vary between individuals and require evaluation by a dentist; every treatment has its own indications, limitations and possible risks. If you have related symptoms or treatment needs, please book a consultation for evaluation by a dentist.

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km 編輯部・《What is a dental crown? Can a missing tooth have a crown? First, is the root still there?》・IDAEO 知識庫・2026-08-13・https://km.idaeo.ai/post/dental/crown-basics

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