What is crown lengthening? Cost, insurance, and whether it hurts｜證據鏈

What is crown lengthening? Cost, insurance, and whether it hurts｜證據鏈

F-Units (fact ledger)

Terms in this section are anchored to the English original. Taiwanese statute names, organisation names and dataset titles are kept in their Taiwanese official form and are not rewritten into the equivalents of any other system.

• F1｜Topic selection basis = full Search Console reconciliation across 14 clinic properties; 「牙冠增長術」 and 5 other query terms total 167,841 impressions across 2 sites.｜source #16｜confidence=high｜basis=internal_dataset｜period=Search Console retention window (from 2025-03-22)｜geo: TW｜caveat: internal data, not a medical claim. Query strings are the Traditional Chinese text Taiwanese users typed and are reproduced verbatim, never translated.
• F2｜The indications for crown lengthening include subgingival caries, crown or root fractures, altered passive eruption, cervical root resorption and short clinical abutment; the purpose is to re-establish the attachment apparatus at a more apical level.｜source #7｜confidence=high｜basis=peer_reviewed｜period=2018｜geo: universal｜caveat: a review article, not a meta-analysis.
• F3｜The term "biologic width" is replaced by "supracrestal tissue attachment", consisting of junctional epithelium and supracrestal connective tissue.｜source #1｜confidence=high｜basis=clinical_guideline (consensus report of the 2017 World Workshop)｜period=2018｜geo: universal｜caveat: a definition of terms, not a claim of efficacy. Translations of this term differ between regions, so the English original governs.
• F4｜Infringement of restorative margins within the supracrestal connective tissue attachment is associated with inflammation and/or loss of periodontal supporting tissue; whether the cause is plaque, trauma or material toxicity is not settled.｜source #1｜confidence=high｜basis=clinical_guideline｜period=2018｜geo: universal｜caveat: the consensus report itself records this as unclear, and this card restates it as such.
• F5｜Subgingival caries or fracture can be managed with this procedure to establish tissue attachment and the ferrule required; in delayed passive eruption it can be used for aesthetic improvement.｜source #2｜confidence=moderate｜basis=peer_reviewed (literature review)｜period=2010｜geo: universal｜caveat: review literature, not a randomised trial.
• F6｜A 1.5- to 2-mm ferrule has a positive effect on the fracture resistance of endodontically treated teeth; where a complete ferrule cannot be provided, an incomplete one is still better than none.｜source #9｜confidence=moderate｜basis=peer_reviewed (literature review including laboratory studies)｜period=2012｜geo: universal｜caveat: predominantly in vitro and simulation studies.
• F7｜The techniques include gingivectomy, gingivoplasty and the apically repositioned flap, the last of which can be combined with osseous resection.｜source #2｜confidence=high｜basis=peer_reviewed｜period=2010｜geo: universal｜caveat: as above.
• F8｜An average of about 3 millimetres of soft tissue rebounds coronal to the alveolar crest, and vertical growth takes a minimum of three months to complete.｜source #2｜confidence=moderate｜basis=peer_reviewed｜period=2010｜geo: universal｜caveat: an average compiled in review literature; individual variation is wide.
• F9｜Final prosthetic treatment should wait at least three months, and possibly up to six months for aesthetically important areas.｜source #2｜confidence=moderate｜basis=peer_reviewed (clinical recommendation)｜period=2010｜geo: universal｜caveat: a recommendation, not a mandatory standard; the individual case is for the dentist to judge.
• F10｜Crown length increased by a 6-month average of 1.4 to 3.3 mm; the gingival margin may rebound, largely during the first three post-operative months.｜source #3｜confidence=moderate｜basis=peer_reviewed (systematic review)｜period=2016｜geo: universal｜caveat: high heterogeneity and high risk of bias among the included studies (stated by the authors).
• F11｜Crown lengthening is performed under local anesthesia; a comparative study of 60 patients contrasted the anterior middle superior alveolar (AMSA) nerve block with local infiltration.｜source #10｜confidence=moderate｜basis=peer_reviewed (comparative study)｜period=2024｜geo: universal｜caveat: single-centre, small sample; the abstract reports no quantitative results.
• F12｜A randomised clinical trial recorded that the majority of subjects had mild to moderate pain and that the trial group recorded no pain after three days; there was no statistically significant difference between groups in pain scores or analgesic consumption.｜source #11｜confidence=moderate｜basis=peer_reviewed (RCT, n=36)｜period=2017｜geo: universal｜caveat: the original study's main purpose was to compare a dressing additive, not to describe the natural history of pain.
• F12b｜Post-operative pain was measured on a visual analogue scale on the day of surgery and at 1, 3 and 7 days afterwards.｜source #12｜confidence=moderate｜basis=peer_reviewed (RCT, n=20)｜period=2025｜geo: universal｜caveat: this card cites only its measurement time points and does not cite its intervention effect as a general recommendation.
• F13｜A systematic review of restoration-driven crown lengthening states that the literature lacks studies of patient-reported outcomes.｜source #3｜confidence=high｜basis=peer_reviewed (systematic review)｜period=2016｜geo: universal｜caveat: this is a statement of an evidence gap, and it is why this card promises no number of days of pain.
• F14｜Meta-analysis: at three and six months, no statistically significant differences between treated and adjacent sites in supracrestal tissue attachment, bone level or pocket depth; at six months the difference in clinical attachment level was significant, in the direction of the adjacent sites.｜source #4｜confidence=moderate｜basis=peer_reviewed (systematic review and meta-analysis, 4 trials)｜period=2023｜geo: universal｜caveat: few included studies; the authors state that more evidence is still needed.
• F15｜Meta-analysis conclusion: it remains debatable whether crown lengthening produces gingival rebound or re-establishes the attachment width, and the included studies carry a high risk of bias.｜source #5｜confidence=moderate｜basis=peer_reviewed (meta-analysis, 5 studies)｜period=2019｜geo: universal｜caveat: the direction of this conclusion is inconsistent with F14, and this card presents both.
• F16｜Surgery produces changes in clinical parameters at the surgical site and at adjacent and non-adjacent sites, which must be considered in surgical planning.｜source #6｜confidence=moderate｜basis=peer_reviewed (systematic review and meta-analysis)｜period=2017｜geo: universal｜caveat: 4 case series included; the authors flag a high risk of bias.
• F17｜In aesthetic crown lengthening in the anterior region, measured at 42, 90 and 180 days after surgery, the amount of rebound correlated with the distance from the gingival margin to the alveolar bone at the time of suturing.｜source #8｜confidence=moderate｜basis=peer_reviewed (prospective study, 21 patients)｜period=2020｜geo: universal｜caveat: a single technique at a single centre.
• F18｜The change in the free gingival margin at six months correlated with the periodontal biotype; deep margin elevation showed a better survival ratio in that review.｜source #13｜confidence=low｜basis=peer_reviewed (systematic review, 6 studies)｜period=2021｜geo: universal｜caveat: the authors state explicitly that most included studies carry a high risk of bias and that long-term trials are lacking; this card uses it only to state that the alternative route exists.
• F19｜For aesthetic crown lengthening in the anterior region there is currently no usable evidence-based standard technique.｜source #7｜confidence=moderate｜basis=peer_reviewed｜period=2018｜geo: universal｜caveat: the authors' own words are 「evidence-based technique is not available」.
• F20｜Osseous resection may affect periodontal stability and may constitute a contraindication to this procedure.｜source #2｜confidence=moderate｜basis=peer_reviewed｜period=2010｜geo: universal｜caveat: a clinical caution, not a quantified risk.
• F21｜A review of 24 clinical studies: cigarette smoking has a negative effect on periodontal wound healing after surgery; 16 studies showed poorer pocket depth and clinical attachment improvement, and 3 showed more residual gingival recession.｜source #14｜confidence=moderate｜basis=peer_reviewed (literature review)｜period=2012｜geo: universal｜caveat: all levels of evidence were included; this is not a graded synthesis.
• F22｜A chlorhexidine-containing rinse used after periodontal surgery improved early wound healing and reduced plaque and gingival inflammation.｜source #15｜confidence=moderate｜basis=peer_reviewed (RCT, 33 patients)｜period=2024｜geo: universal｜caveat: the study carries a manufacturer funding disclosure; medication must be prescribed by a dentist and this card endorses no product.
• F23｜In teeth with no coronal structure, where a ferrule has to be created, orthodontic extrusion should be considered rather than surgical crown lengthening.｜source #9｜confidence=moderate｜basis=peer_reviewed (literature review)｜period=2012｜geo: universal｜caveat: applicability is limited by root length and periodontal condition.
• F24｜Article 63 of Taiwan's Medical Care Act: medical care institutions shall explain the reasons for surgical operation, success rate, possible side-effects and risks, and must obtain consent and signature on the letter of consent for surgery and anesthesia before commencing with the surgical procedure.｜source #17｜confidence=high｜basis=law｜period=current text (tested 2026-08-05)｜geo: TW｜caveat: a restatement of the provision, not legal advice; Taiwanese law, not applicable in other jurisdictions. The wording here follows the official English text of the Laws and Regulations Database.
• F25｜Article 51 of Taiwan's National Health Insurance Act lists items not covered, including "cosmetic surgery" and "Dentures, artificial eyes, spectacles, hearing aids, wheelchairs, canes, and other treatment equipment not required for positive therapy".｜source #18｜confidence=high｜basis=law｜period=current text (tested 2026-08-05)｜geo: TW｜caveat: the same anchor as card #9, C2; an enumeration in a statute is not a conclusion about an individual case, and this card makes no such determination. Taiwanese law, not applicable in other jurisdictions.
• F26｜Self-pay fee items follow the fee schedule approved or filed with the local health authority; the verified example is dataset 121913 「臺北市醫療收費標準」 on Taiwan's government open data platform.｜source #19｜confidence=high｜basis=official_statement｜period=tested 2026-08-05, HTTP 200, title matches verbatim｜geo: TW｜caveat: the same anchor as card #9, C3 (the Taipei City health bureau announcement link parameters cited in card #9 were not re-verified here; this card uses the open dataset as the verified anchor); other counties' pages to be verified one by one before scaling.
• F27｜The 「醫材比價網」 of Taiwan's National Health Insurance Administration is the official portal for querying medical device charges, and the portal itself was confirmed reachable.｜source #20｜confidence=moderate｜basis=official_statement｜period=tested 2026-08-05, HTTP 200｜geo: TW｜caveat: the same anchor as card #9, C4; the page loads dynamically and whether this topic (periodontal surgical procedures) has any queryable item there was unverified.; corrected by OP testing on 2026-08-05: the site contains no dental items, there is no corresponding queryable entry for periodontal surgical procedures, and it may not be used as a verification channel for this topic
• F28[unverified]｜Whether private insurance pays for crown lengthening depends on the terms of the policy.｜source class: policy terms (no publicly citable specimen obtained)｜confidence=low｜basis=to be supplied｜geo: TW｜caveat: this site offers no opinion on claims (editorial policy) and states only that it depends on the policy terms.
• F29[unverified]｜The coverage status of crown lengthening under Taiwan's National Health Insurance fee schedule.｜source class: the Administration's published schedule of medical service benefit items and payments｜confidence=low｜basis=to be supplied (www.nhi.gov.tw returned 403 to curl on 2026-08-05 and no verbatim anchor was obtained; to be re-verified through a browser before publication)｜geo: TW｜caveat: until verified, this card asserts neither coverage nor non-coverage.
• F30[editorial synthesis]｜The four-part breakdown - pre-operative assessment / surgery / additions during surgery / subsequent restoration - and the advice on comparing quotations are a reading framework defined by this site's editors. They are not a factual claim and not any organisation's fee classification.｜confidence=n/a｜basis=editorial｜geo: TW｜caveat: must not be marked as unverified (which would manufacture fake verification work).
• F31｜Article 87 of Taiwan's Medical Care Act: publications of new medical knowledge or research results, health education for patients, or academic publications which do not involve solicitation for medical practices shall not be regarded as advertisements for medical care.｜source #21｜confidence=high｜basis=law｜period=current text (tested 2026-08-05)｜geo: TW｜caveat: the basis on which this card is positioned; Taiwanese law. The wording follows the official English text of the Laws and Regulations Database.

Sources

Bibliographic entries are given in the English original. Taiwanese statutes and official pages keep their Traditional Chinese official names.

1. Jepsen S, Caton JG, Albandar JM, et al. Periodontal manifestations of systemic diseases and developmental and acquired conditions: Consensus report of workgroup 3 of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions. J Periodontol. 2018;89 Suppl 1:S237-S248. PMID 29926943. https://pubmed.ncbi.nlm.nih.gov/29926943/ (retrieved 2026-08-05, HTTP 200). Verbatim span (English original, keeping the master card's 「」 marking): 「the term biologic width is replaced by supracrestal tissue attachment consisting of junctional epithelium and supracrestal connective tissue」「infringement of restorative margins within the supracrestal connective tissue attachment is associated with inflammation and/or loss of periodontal supporting tissue」
2. Hempton TJ, Dominici JT. Contemporary crown-lengthening therapy: a review. J Am Dent Assoc. 2010;141(6):647-655. PMID 20516094. https://pubmed.ncbi.nlm.nih.gov/20516094/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「an average of 3 millimeters of supragingival soft tissue will rebound coronal to the alveolar crest and can take a minimum of three months to complete vertical growth」「Initiation of final prosthetic treatment should wait at least three months and possibly up to six months for esthetically important areas」
3. Pilalas I, Tsalikis L, Tatakis DN. Pre-restorative crown lengthening surgery outcomes: a systematic review. J Clin Periodontol. 2016;43(12):1094-1108. PMID 27535216. https://pubmed.ncbi.nlm.nih.gov/27535216/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「CLS resulted in increased crown length (6-month average: 1.4-3.3 mm)」「gingival margin may rebound, largely during the first three postoperative months」「The literature lacks studies on ... patient- and referring dentist-reported outcomes」
4. Smith SC, Goh R, Ma S, et al. Periodontal tissue changes after crown lengthening surgery: A systematic review and meta-analysis. Saudi Dent J. 2023;35(4):294-304. PMID 37251724. https://pubmed.ncbi.nlm.nih.gov/37251724/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「no statistically significant changes after three or six months in terms of supracrestal tissue attachment levels, bone level and probing pocket depth between treated and adjacent sites」
5. Al-Sowygh ZH. Does Surgical Crown Lengthening Procedure Produce Stable Clinical Outcomes for Restorative Treatment? A Meta-Analysis. J Prosthodont. 2019;28(1):e103-e109. PMID 29876998. https://pubmed.ncbi.nlm.nih.gov/29876998/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「It remains debatable whether SCL produces gingival rebound, or re-establishes BW and changes in clinical attachment level」
6. Nobre CM, de Barros Pascoal AL, Albuquerque Souza E, et al. A systematic review and meta-analysis on the effects of crown lengthening on adjacent and non-adjacent sites. Clin Oral Investig. 2017;21(1):7-16. PMID 27515522. https://pubmed.ncbi.nlm.nih.gov/27515522/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「Clinical and esthetic alterations on the adjacent/non-adjacent teeth ... must be considered in surgical planning」
7. Marzadori M, Stefanini M, Sangiorgi M, et al. Crown lengthening and restorative procedures in the esthetic zone. Periodontol 2000. 2018;77(1):84-92. PMID 29493814. https://pubmed.ncbi.nlm.nih.gov/29493814/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「Its indications include subgingival caries, crown or root fractures, altered passive eruption, cervical root resorption and short clinical abutment」「an evidence-based technique is not available」
8. Domínguez E, Pascual-La Rocca A, Valles C, et al. Stability of the gingival margin after an aesthetic crown lengthening procedure in the anterior region by means of a replaced flap and buccal osseous surgery: a prospective study. Clin Oral Investig. 2020;24(10):3633-3640. PMID 32124069. https://pubmed.ncbi.nlm.nih.gov/32124069/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「Clinical measurements were recorded pre-surgically; immediately post-surgically (baseline); and at 42, 90, and 180 days」「Tissue rebound seems to be related to the distance from the GM to the alveolar bone (AB) at the time of suturing」
9. Juloski J, Radovic I, Goracci C, et al. Ferrule effect: a literature review. J Endod. 2012;38(1):11-19. PMID 22152612. https://pubmed.ncbi.nlm.nih.gov/22152612/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「The presence of a 1.5- to 2-mm ferrule has a positive effect on fracture resistance of endodontically treated teeth」「In teeth with no coronal structure, in order to provide a ferrule, orthodontic extrusion should be considered rather than surgical crown lengthening」
10. Prakash N, Melath A, Kayakool S, et al. Anesthetic Potential of Anterior Middle Superior Alveolar Nerve Block vs Local Infiltration on Crown Lengthening in Maxilla - A Comparative Study. Indian J Dent Res. 2024;35(4):403-405. PMID 39902478. https://pubmed.ncbi.nlm.nih.gov/39902478/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「A total of 60 patients indicated for crown lengthening ... divided into two groups: Group A (AMSA) and Group B (local infiltration)」
11. Askari M, Saffarpour A, Purhashemi J, Beyki A. Effect of Propolis Extract in Combination with Eugenol-Free Dressing (Coe-Pak) on Pain and Wound Healing after Crown-Lengthening: A Randomized Clinical Trial. J Dent (Shiraz). 2017;18(3):173-180. PMID 29034271. https://pubmed.ncbi.nlm.nih.gov/29034271/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「In both groups, the majority of patients experienced moderate and mild pain and there was no pain in the trial group after three days」
12. Behfarnia P, Birang R, Ghaznavi A, Mirghaderi SA. Effect of photobiomodulation on wound healing and pain after crown lengthening surgery: A randomized clinical trial. J Adv Periodontol Implant Dent. 2025;17(3):172-178. PMID 41064025. https://pubmed.ncbi.nlm.nih.gov/41064025/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「Pain severity was quantified on the day of surgery and 1, 3, and 7 days after surgery using a visual analog scale」
13. Mugri MH, Sayed ME, Nedumgottil BM, et al. Treatment Prognosis of Restored Teeth with Crown Lengthening vs. Deep Margin Elevation: A Systematic Review. Materials (Basel). 2021;14(21):6733. PMID 34772259. https://pubmed.ncbi.nlm.nih.gov/34772259/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「A tissue rebound was seen that was correlated to the periodontal biotype」「the deep margin elevation technique has a better survival ratio」
14. Javed F, Al-Rasheed A, Almas K, Romanos GE, Al-Hezaimi K. Effect of cigarette smoking on the clinical outcomes of periodontal surgical procedures. Am J Med Sci. 2012;343(1):78-84. PMID 21804361. https://pubmed.ncbi.nlm.nih.gov/21804361/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「Twenty-four clinical studies were included」「Cigarette smoking has a negative effect on periodontal wound healing after surgical interventions」
15. Graziani F, Izzetti R, Perić M, Marhl U, Nisi M, Gennai S. Early periodontal wound healing after chlorhexidine rinsing: a randomized clinical trial. Clin Oral Investig. 2024;28(6):354. PMID 38833009. https://pubmed.ncbi.nlm.nih.gov/38833009/ (retrieved 2026-08-05, HTTP 200). Verbatim span: 「The usage of CHX-ADS following periodontal surgery improved early wound healing, reduced plaque accumulation and gingival inflammation」
16. km dental-line topic ledger: `analysis/reports/km-dental-backlog.md` #17 appendix (6 query terms itemised, 167,841 impressions in total, across 2 sites); data source = full Search Console reconciliation of 14 clinic properties.
17. Taiwan Medical Care Act (《醫療法》) Article 63, Laws and Regulations Database. https://law.moj.gov.tw/LawClass/LawSingle.aspx?pcode=L0020021&flno=63 (retrieved 2026-08-05, HTTP 200, text matches verbatim; official English title "Medical Care Act" confirmed on the database's English edition on 2026-08-06)
18. Taiwan National Health Insurance Act (《全民健康保險法》) Article 51, Laws and Regulations Database. https://law.moj.gov.tw/LawClass/LawSingle.aspx?pcode=L0060001&flno=51 (retrieved 2026-08-05, HTTP 200, text matches verbatim; official English title "National Health Insurance Act" confirmed on the database's English edition on 2026-08-06)
19. Taiwan government open data platform, dataset 121913 「臺北市醫療收費標準」. https://data.gov.tw/dataset/121913 (retrieved 2026-08-05, HTTP 200; the API `/api/v2/rest/dataset/121913` returns title = 「臺北市醫療收費標準」)
20. Portal of the 「醫材比價網」 of the National Health Insurance Administration, Ministry of Health and Welfare, Taiwan. https://info.nhi.gov.tw/INAE2000/INAE2010S01 (retrieved 2026-08-05, HTTP 200; page content loads dynamically and item applicability is unverified)
21. Taiwan Medical Care Act (《醫療法》) Article 87, Laws and Regulations Database. https://law.moj.gov.tw/LawClass/LawSingle.aspx?pcode=L0020021&flno=87 (retrieved 2026-08-05, HTTP 200, text matches verbatim)

Internal citation chain

• If a crown follows the surgery, how to read the terms of the fee: What a single crown costs / how to read an implant quotation (km-drafts/km-09-implant-cost.md, sharing anchors C2 / C3 / C4)
• The two meanings of 「牙套」 in search (orthodontic appliance versus prosthetic crown) are separated in: What does a 「牙套」 cost (km-drafts/km-08-braces-vs-crown-cost.md)

Publication gate reminder: this card is a draft. It may not be marked published while F28 and F29 remain unverified, and it may not enter km_entries until all four language editions (zh-Hant / zh-Hans / en / ja) exist.