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Which teeth are the molars? And why is the second molar the one people ask about?｜證據鏈

km 編輯部2026-08-13About 16 min read
#證據鏈#牙醫KM#智齒#咬合

本頁是〈Which teeth are the molars? And why is the second molar the one people ask about?〉的事實單元帳：每一條主張對應的來源、證據等級、地域與期間、原文引句與限制，逐條攤開。

Which teeth are the molars? And why is the second molar the one people ask about?｜證據鏈

F-Units (fact ledger)

In each unit below, `span` is a verbatim quotation from the source. The original language is English and the master card's 「」 marking is retained; spans are not translated, not rewritten and not reordered. The surrounding text is this card's restatement and its limits.
  • F1｜confidence: verified｜basis: internal_dataset｜period: Search Console 2025-03 to 2026-08｜geo: TW｜span: the 10 query terms of backlog #21 total 156,468 impressions across 6 sites -(term x site x impressions itemised in the km-dental-backlog.md #21 appendix)｜caveat: impressions are a property-level figure, not de-duplicated traffic; the listing follows the queue page column for #21 with no additions or removals; this unit is not emitted when the card is converted for publication (2026-08-05 ruling that internal data does not enter the visible layer)
  • F2｜confidence: verified｜basis: textbook (StatPearls, PMID 34033352)｜period: entry updated 2023-05-22, 2026 version｜geo: universal｜span: 「There are typically 20 deciduous teeth divided evenly across the maxilla and mandible」「The deciduous teeth eventually exfoliate and are replaced by 32 permanent teeth: 16 in the maxilla and 16 in the mandible」「Permanent teeth are classified as incisors, canines, premolars, and molars, while primary teeth do not include premolars」｜caveat: a textbook-type entry, not primary research; tooth counts are typical values and an individual may have congenitally missing or supernumerary teeth
  • F3｜confidence: verified (NCBI Bookshelf full text retrieved with ego-browser and compared verbatim on 2026-08-06)｜basis: textbook (StatPearls, Anatomy, Head and Neck, Teeth; NBK557543)｜period: entry updated 2023-07-24｜geo: universal｜span: 「The primary incisors, canines, and molars get replaced by the successional permanent incisors, canines, and premolars. Permanent dentition also consists of the additional teeth that are three types of molars - first, second, and third」｜caveat: the span comes from the Bookshelf full-text page, not the PubMed abstract, so this unit carries no PMID prefix, to stop km-gate --spans comparing it against the wrong text; for the PubMed entry see source #2
  • F4｜confidence: verified (retrieved as for F3)｜basis: textbook (NBK557543)｜period: entry updated 2023-07-24｜geo: universal｜span: 「The permanent first molars erupt between 6 to 7 years of age. The permanent second molars erupt between 11 to 13 years of age. The permanent third molars erupt between 17 to 21 years of age if there is room for them」｜caveat: the textbook gives typical ranges, which do not fully coincide with the ranges from population studies (see F13); not to be used as a criterion for any individual child
  • F5｜confidence: verified (retrieved as for F3)｜basis: textbook (NBK557543)｜period: entry updated 2023-07-24｜geo: universal｜span: 「In the maxilla, permanent adult teeth are numbered 1 through 16 from right to left, and primary teeth are labeled with letters A through J from right to left. In the mandible, permanent adult teeth are numbered 17 through 32 from left to right, and primary teeth are labeled with letters K through T from left to right」｜caveat: this entry uses the US universal numbering as its frame of description, which is not the international standard; when seeking care in another country, do not assume the same system is in use
  • F6｜confidence: verified (retrieved as for F3)｜basis: textbook (NBK557543)｜period: entry updated 2023-07-24｜geo: universal｜span: 「Teeth provide a masticatory system that functions in the incising, tearing and grinding of food」「Retention of function, aesthetics, and natural dentition of at least 20 teeth with nine to ten occluding pairs (including anterior teeth) is associated with adequate masticatory efficiency and ability」｜caveat: a statement about the function of the dentition as a whole, not a ranking of individual teeth; the source states an association, not causation. The sentence about the World Health Organization treating tooth count as a key indicator sits between the two span fragments above and is verifiable on the same full-text page (re-checked 2026-08-06: 「The World Health Organization (WHO) considers the number of teeth to be a key indicator of oral health status」); this unit keeps the master card's span unchanged rather than extending it
  • F7｜confidence: verified (reachability confirmed with ego-browser on 2026-08-06; curl returns 403, which is tool-side blocking. The standard page and the publicly readable OBP sections were compared verbatim)｜basis: official_statement (international standard ISO 3950:2016, ISO/TC 106/SC 3)｜period: fourth edition 2016, confirmed still current at the 2022 review; ISO/AWI 3950 under revision｜geo: universal｜span: 「This International Standard provides a system for designating teeth or areas of the oral cavity using two digits」「The system described in this International Standard was originally drawn up by the FDI World Dental Federation and approved by the World Health Organization (WHO) and Technical committee ISO/TC 106, Dentistry」「This fourth edition cancels and replaces the third edition (ISO 3950:2009), which has been technically revised」｜caveat: Clause 4 of the standard (designation of teeth) is paywalled and its wording was not obtained for this card; the quadrant and tooth-position correspondence is therefore taken from the openly published descriptions in F8 and F9
  • F8｜confidence: verified (full text retrieved locally with efetch db=pmc on 2026-08-06 and re-checked verbatim on the PMC page with ego-browser)｜basis: peer_reviewed (Journal of Imaging 2026; PMC13301722)｜period: published 2026-06｜geo: universal｜span: 「This system encodes the position of each tooth using a two-digit number: the first digit denotes the quadrant (1–4, corresponding to the upper right, upper left, lower left, and lower right, respectively), and the second digit represents the tooth’s position within that quadrant (1–8, counted from the midline posteriorly)」｜caveat: this is an imaging-recognition paper describing the standard, not the standard's own text; the span comes from the PMC open-access full text rather than the PubMed abstract, so it carries no PMID prefix - for the PubMed entry see source #16
  • F9｜confidence: verified (full text retrieved locally with efetch db=pmc and compared verbatim on 2026-08-06)｜basis: peer_reviewed (Saudi Dent J 2016; PMC5110463)｜period: published 2016｜geo: universal｜span: 「Zsigmondy developed a numbering sequence from 1 to 8 for permanent dentition, starting from the central incisor (1) until the third molar (8), and roman numerals I to V (later modified, A to E) for primary dentition」「uses consecutive integers, beginning with the upper right third molar (designated as #1), and counts clockwise around the dentition, finishing with the lower right third molar (designated as #32)」「The first digit indicates the quadrant and the second digit refers to the tooth」｜caveat: the survey population of that study was limited to heads of dental institutions in Saudi Arabia, and its usage-rate findings cannot be extrapolated elsewhere; this card cites only its descriptive passages on the three systems and does not cite the usage-rate conclusion. The span comes from the PMC open-access full text and carries no PMID prefix - for the PubMed entry see source #15
  • F10｜confidence: verified｜basis: peer_reviewed (PMID 8349894)｜period: published 1993｜geo: universal｜span: 「Today, three systems are favored worldwide: the Zsigmondy/Palmer system, the universal system, and the FDI two-digit system」｜caveat: a 1993 paper, used here to support the structural fact that three systems coexist; its arguments about the merits of each system are not cited
  • F11｜confidence: verified｜basis: peer_reviewed (PMID 24025897)｜period: published 2013｜geo: universal｜span: 「Three systems are favored worldwide: the Zsigmondy/Palmer system, the Universal system, and the Federation Dentaire Internationale (FDI) Two-Digit system」「The FDI Two-Digit system is widely used throughout the world, except USA」｜caveat: the paper's own subject is a proposed additional rule for notating supernumerary teeth; this card cites only its description of the three current systems
  • F12｜confidence: verified｜basis: peer_reviewed (PMID 38298675)｜period: published 2024｜geo: universal｜span: 「The outcome of a questionnaire disseminated among 66 personnel showed the confusion existing among currently used tooth numbering systems」｜caveat: a questionnaire of only 66 people at a single institution can show that confusion exists but cannot quantify how widespread it is; the new system that paper proposes is neither cited nor endorsed here
  • F13｜confidence: verified｜basis: peer_reviewed (PMID 38426348, systematic review and meta-analysis)｜period: searched to 2023-04, published 2024｜geo: universal｜span: 「The mandibular first molar eruption was found to be as early as 4.09 years while the maxillary second molar erupted as late as 13.45 years」「included from 80 studies of which, 41 were carried out in Asia」「Meta-regression interpreted tooth eruption to be earlier in females and in the mandible」｜caveat: the included studies mix cross-sectional and longitudinal designs, with differing national definitions and reading criteria; what is cited here are the endpoints of population ranges, not a criterion for an individual child
  • F14｜confidence: verified｜basis: peer_reviewed (PMID 28644755)｜period: survey data 2009 to 2014, published 2017｜geo: universal (nationally representative US sample)｜span: 「Forty-eight percent of 6-y-olds and 98% of 8-y-olds had all FPMs emerged, whereas SPM emergence varied more」｜caveat: the data source is the US National Health and Nutrition Examination Survey, whose population composition differs from other regions; the study's own subject is the association between BMI and emergence timing, which this card does not cite. In the original, FPM = first permanent molar and SPM = second permanent molar; "all FPMs" means all four have emerged
  • F15｜confidence: verified｜basis: peer_reviewed (PMID 10620156)｜period: published 1999｜geo: universal｜span: 「These variables were recorded using the Dental Prescale System in 16 healthy young adults」「The distribution of the occlusal force was greatest at the molar region followed by the premolar and anterior teeth region」「The proportion of occlusal force (occlusal force at each region/total occlusal force) on molar regions increased as clenching strength increased」｜caveat: a laboratory measurement in only 16 healthy young adults, not a population survey; it supports the direction of distribution between regions and no force value for any individual tooth. The body text describes the device as an occlusal pressure measurement system and does not carry the product name, which is kept in this span for traceability
  • F16｜confidence: verified｜basis: peer_reviewed (PMID 26066662, systematic review)｜period: searched 2003 to 2014, published 2015｜geo: universal｜span: 「Studies exposing data on subjects with SDA (3-5 posterior occluding pairs) or ESDA (0-2 posterior occluding pairs) and on masticatory performance with RDP were included」「Comminution or mixing ability in subjects with (E)SDA was 28-39% lower compared to that of subjects with complete dentitions」｜caveat: few studies were included; this is the same anchor as this site's KM-DENTAL-34 card, which carries the full context - this card cites without rewriting. SDA = shortened dental arch and ESDA = extremely shortened dental arch, as defined by that study
  • F17｜confidence: verified｜basis: peer_reviewed (PMID 39853442, systematic review and meta-analysis)｜period: literature of the past decade, published 2025-01｜geo: universal｜span: 「Thirteen studies met the inclusion criteria and underwent analysis; they included a total of 13,788 patients」「The overall prevalence of caries in MSMs adjacent to IMTMs was 29.89% (CI 95%: 21.05 - 38.74%; p < 0.001)」「the mesioangular position was the most frequently associated with caries with 43.37%」｜caveat: this is a pooling of prevalence (cross-sectional), not incidence, and cannot establish causation; study quality was appraised with the Newcastle-Ottawa scale and heterogeneity is not reported in the abstract. In the original, MSM = mandibular second molar and IMTM = impacted mandibular third molar (wisdom tooth)
  • F18｜confidence: verified｜basis: peer_reviewed (PMID 32112019, systematic review)｜period: searched to 2016-06, published 2020｜geo: universal｜span: 「The search yielded 81 records and, after application of inclusion and exclusion criteria, two incidence studies were included in this systematic review」「Both cohort studies indicated that DSC incidence was higher when third molars were erupted in the intermediate term, but greater over the long term for an ageing male population」「further high-quality research is required to improve the accuracy of these findings」｜caveat: only 2 cohort studies, so the evidence is extremely limited; the population for the long-term result is an ageing male one and cannot be extrapolated to people generally. In the original, DSC = distal surface caries
  • F19｜confidence: verified｜basis: peer_reviewed (Cochrane systematic review, PMID 32368796; CD003879.pub5)｜period: published 2020-05; the current version after the 2005, 2012 and 2016 ones, with a PubMed search on the same topic on 2026-08-06 finding no newer version｜geo: universal｜span: 「Insufficient evidence is available to determine whether asymptomatic disease-free impacted wisdom teeth should be removed or retained」「Although retention of asymptomatic disease-free impacted wisdom teeth may be associated with increased risk of periodontitis affecting adjacent second molars in the long term, the evidence is very low certainty」「Given the current lack of available evidence, patient values should be considered and clinical expertise used to guide shared decision-making」｜caveat: only 1 RCT and 1 prospective cohort study were included, giving low to very low certainty; the conclusion applies only to asymptomatic, disease-free impacted wisdom teeth and not to teeth that are already symptomatic
  • F20｜confidence: verified｜basis: peer_reviewed (PMID 42320181, systematic review and meta-analysis)｜period: published online 2026-06-11, issue dated 2026-09 (as of this card's date, 2026-08-06, the abstract is retrievable and marked Indexed for MEDLINE); an update of a previous 2016 comprehensive review｜geo: universal｜span: 「A total of 125 data points comprising 87,282 individuals were included」「The pooled global prevalence of M3 agenesis was 23.07% (95% CI: 21.2-25.0%)」「with substantial heterogeneity across studies」｜caveat: heterogeneity across studies is very high and regional differences are large; what is counted is the prevalence of at least one congenitally absent (agenesis, never formed) wisdom tooth - not teeth that were extracted or lost later, and not the absence of all four
  • F21｜confidence: verified｜basis: peer_reviewed (Cochrane systematic review, PMID 28759120)｜period: searched to 2016-08, published 2017-07; a PubMed search on the same topic on 2026-08-06 found no newer version｜geo: universal｜span: 「We included 38 trials that involved a total of 7924 children」「second-, third- and fourth-generation resin-based sealants prevented caries in first permanent molars in children aged 5 to 10 years」「at 24 months follow-up: OR 0.12, 95% CI 0.08 to 0.19, 7 trials」「moderate-quality evidence」「This is an update of a review published in 2004, 2008 and 2013」｜caveat: the principal evidence comes from children aged 5 to 10 and from the more anterior molars (first permanent molars, the group ending in 6), and some trials date from the 1970s; whether it applies to a given child or to an adult is for a dentist to assess, and this card gives no treatment advice
  • F23｜confidence: verified (full text retrieved locally with efetch db=pmc and compared verbatim on 2026-08-06)｜basis: peer_reviewed (Cureus 2026 case report; PMC13092278)｜period: published 2026-03｜geo: universal｜span: 「The following numbered teeth correspond to the Fédération Dentaire Internationale (FDI) tooth numbering system for primary dentition. The first digit corresponds to the quadrant of the mouth, and the second digit corresponds to the tooth's position within that quadrant, numbered from the midline posteriorly」「Teeth 54 and 55 received stainless-steel crowns, and tooth 52 received a pulpotomy in the maxillary right quadrant」｜caveat: a case report is low-level clinical evidence; this card cites only its figure legend's statement of the two-digit rule for primary teeth and the example quadrant digits, and cites none of its clinical content. The span comes from the PMC open-access full text and carries no PMID prefix - for the PubMed entry see source #22
  • F22｜confidence: editorial synthesis (an editorial framework, not an external factual claim)｜basis: editorial_framework｜period: 2026-08-06｜geo: universal｜span: 「the molar / premolar disambiguation」「referring to the three molars by their final digit 6 / 7 / 8 to avoid ordinal confusion」「the three confirming actions for a tooth number」「the worked example matching number 37 to universal number 2 (derived from the rules described in F8 and F9)」「the division-of-labour statement with respect to KM-DENTAL-34」 are all communication scaffolding assembled by this site from F2 to F21｜caveat: not a clinical criterion and not a diagnostic tool; this card does not rank teeth by importance and does not replace assessment by a dentist. The English edition additionally notes that the everyday Chinese and Japanese word covers both classes - also an editorial note, not a new factual claim

Sources

Retrieved and verified on 2026-08-06. PubMed entries were compared verbatim against abstracts obtained through E-utilities efetch, and each entry page was tested for a 200 response; PMC entries were retrieved as open-access full text with efetch db=pmc; the NCBI Bookshelf and ISO pages were confirmed reachable with ego-browser and compared verbatim.

  1. Aruede G, Pepper T. Anatomy, Permanent Dentition. StatPearls. PMID 34033352
  2. Morris AL, Tadi P. Anatomy, Head and Neck, Teeth. StatPearls (NCBI Bookshelf full text)
  3. Aruede G, Pepper T. Anatomy, Permanent Dentition. StatPearls (the NCBI Bookshelf full-text counterpart of source #1; no text from it is separately cited in the F-Units of this card)
  4. ISO 3950:2016 Dentistry — Designation system for teeth and areas of the oral cavity (standard page)
  5. ISO 3950:2016 openly published sections (ISO Online Browsing Platform: Foreword, Introduction, Scope)
  6. Peck S, Peck L. A time for change of tooth numbering systems. J Dent Educ. 1993. PMID 8349894
  7. Yadav SS, Sonkurla S. Sarjeev's supernumerary tooth notation system. Indian J Dent Res. 2013. PMID 24025897
  8. Shehabeldin RR, Hamama HH. Introduction of qpdb teeth numbering system. Heliyon. 2024. PMID 38298675
  9. Vandana S, et al. Global variations in eruption chronology of permanent teeth: A systematic review and meta-analysis. Am J Hum Biol. 2024. PMID 38426348
  10. Pahel BT, et al. A Contemporary Examination of First and Second Permanent Molar Emergence. J Dent Res. 2017. PMID 28644755
  11. Kumagai H, et al. Occlusal force distribution on the dental arch during various levels of clenching. J Oral Rehabil. 1999. PMID 10620156
  12. Liang S, et al. Effects of removable dental prostheses on masticatory performance of subjects with shortened dental arches: A systematic review. J Dent. 2015. PMID 26066662
  13. Revuelta-Cortés P, et al. Prevalence of distal caries in second molar associated with impacted mandibular third molar. Clin Oral Investig. 2025. PMID 39853442
  14. Toedtling V, et al. A systematic review of second molar distal surface caries incidence in the context of third molar absence and emergence. Br Dent J. 2020. PMID 32112019
  15. Al-Johany SS. Tooth Numbering System in Saudi Arabia: Survey. Saudi Dent J. 2016. PMID 27872549 (open-access full text PMC5110463)
  16. Structure-Guided Tooth Numbering and Lesion Localization in Visible Light Oral Images. J Imaging. 2026. PMID 42346919 (open-access full text PMC13301722)
  17. Ghaeminia H, et al. Surgical removal versus retention for the management of asymptomatic disease-free impacted wisdom teeth. Cochrane Database Syst Rev. 2020. PMID 32368796
  18. Angelakopoulos N, et al. Third molar agenesis: An updated systematic review and meta-analysis. Arch Oral Biol. Online ahead of print 2026-06-11 (issue 2026 Sep). PMID 42320181
  19. Ahovuo-Saloranta A, et al. Pit and fissure sealants for preventing dental decay in permanent teeth. Cochrane Database Syst Rev. 2017. PMID 28759120
  20. Internal data: `analysis/reports/km-dental-backlog.md` #21 appendix (term x site x impressions, itemised and reconcilable)
  21. Editorial framework: this site's molar disambiguation, final-digit naming, three confirming actions for a number, and division-of-labour statement (no external source; marked as editorial synthesis)
  22. Bilateral Cavernous Sinus Thrombosis Secondary to Dental Infection-Induced Sinusitis: A Case Report. Cureus. 2026. PMID 42011457 (open-access full text PMC13092278; this card cites only its primary-tooth numbering figure legend)

Internal citation chain

  • Whether a molar needs replacing after extraction, and the options: If a molar is pulled, can it just be left? What happens then? (KM-DENTAL-34)
  • Whether and how to restore a decayed molar: Does a cavity always have to be filled? How is a filling done? (KM-DENTAL-12)
  • The healing timeline of the socket after an extraction (including wisdom teeth): How long does an extraction socket take to heal? (KM-DENTAL-01)
Publication gate reminder: this card is a draft. It may not enter km_entries until all four language editions (zh-Hant / zh-Hans / en / ja) are complete. The spans of F3 through F9 come from Bookshelf full text, the openly published ISO sections and PMC open-access full text rather than from PubMed abstracts; for manual re-verification before publication, use the links at sources #2, #3, #4, #5, #15 and #16.

FAQ

Exactly which teeth are the molars? Do premolars count?
**In the literature and in clinical records, premolars and molars are two different classes of tooth.** The permanent dentition is classified as incisors, canines, premolars and molars [F2]; by tooth number, counting back from the midline in each quadrant, teeth 4 and 5 are the premolars and teeth 6, 7 and 8 are the molars [F8]. Everyday speech in Chinese and Japanese lumps them together under one word, so when describing symptoms, "the nth tooth back on the upper right" is more precise than "my back tooth".
臼歯とは結局どの歯ですか。小臼歯も入りますか。 — **文献とカルテでは、小臼歯と大臼歯は別の分類の歯です。** 永久歯は切歯・犬歯・小臼歯・大臼歯の 4 つに分類されます [F2]。歯式の番号でいえば、各象限で正中から後ろへ数えて 4 番目・5 番目が小臼歯、6 番目・7 番目・8 番目が大臼歯です [F8]。日常語の「臼歯」は両方をまとめて指すので、症状を伝えるときは「臼歯」より「上の右側の奥から数えて何本目」と言うほうが正確です。
Exactly which teeth are the molars? Do premolars count? — **In the literature and in clinical records, premolars and molars are two different classes of tooth.** The permanent dentition is classified as incisors, canines, premolars and molars [F2]; by tooth number, counting back from the midline in each quadrant, teeth 4 and 5 are the premolars and teeth 6, 7 and 8 are the molars [F8]. Everyday speech in Chinese and Japanese lumps them together under one word, so when describing symptoms, "the nth tooth back on the upper right" is more precise than "my back tooth".
My chart says "37" - which tooth is that? And why is it a different number elsewhere?
**In the FDI two-digit system, 37 is the lower left quadrant, seventh from the midline - the lower left second molar [F8][F22].** Different numbers appear because three notation systems coexist worldwide [F10][F11]: the universal system counts clockwise from the upper right wisdom tooth (number 1) to the lower right wisdom tooth (number 32) [F9], while Zsigmondy/Palmer uses 1 to 8 plus a quadrant symbol [F9]. The same tooth simply has different notations in different systems, so when they do not match, ask which system is in use [F12].
カルテの「37」はどの歯ですか。別の場所では違う番号なのはなぜですか。 — **FDI の 2 桁方式では、37 は左下象限で正中から数えて 7 本目、つまり左下の第二大臼歯です [F8][F22]。** 違う番号が出てくるのは、世界に 3 つの表記法が併存しているからです [F10][F11]。ユニバーサル方式は右上の親知らず（1 番）から時計回りに右下の親知らず（32 番）まで数えます [F9]。ジグモンディ／パーマー方式は 1 から 8 に象限記号を添えます [F9]。同じ歯でも方式が違えば書き方が違うだけなので、食い違いを見たらまずどの方式かを尋ねてください [F12]。
My chart says "37" - which tooth is that? And why is it a different number elsewhere? — **In the FDI two-digit system, 37 is the lower left quadrant, seventh from the midline - the lower left second molar [F8][F22].** Different numbers appear because three notation systems coexist worldwide [F10][F11]: the universal system counts clockwise from the upper right wisdom tooth (number 1) to the lower right wisdom tooth (number 32) [F9], while Zsigmondy/Palmer uses 1 to 8 plus a quadrant symbol [F9]. The same tooth simply has different notations in different systems, so when they do not match, ask which system is in use [F12].
Is the second molar more important than other teeth?
**The literature found for this card does not rank teeth by importance, so this card makes no such claim [F22].** What can be said are verifiable facts: occlusal force distribution is greatest at the molar region, ahead of the premolar and anterior regions (small-sample measurement) [F15]; people with fewer posterior occluding pairs showed chewing performance 28% to 39% lower [F16]; and about 23.07% of people have at least one congenitally absent wisdom tooth, for whom the second molar is the functional terminal tooth on that side [F20]. What role a given tooth plays in your mouth must be assessed by a dentist against your own occlusion and any missing teeth.
第二大臼歯はほかの歯より重要なのですか。 — **本カードが調べた文献は歯に重要度の順位をつけていないので、本カードもそのような主張はしません [F22]。** 言えるのは検証可能な事実だけです。咬合力の分布は大臼歯部が小臼歯部・前歯部より大きい（小標本の測定）[F15]。臼歯部の咬合する対数が少ない人は咀嚼のパフォーマンスが 28% から 39% 低い [F16]。およそ 23.07% の人は親知らずが少なくとも 1 本先天欠如しており、その人にとって第二大臼歯はその側で機能する最後方の歯になる [F20]。あなたの口のなかで 1 本 1 本が果たしている役割は、歯科医師があなたの咬合と欠損の状態に照らして評価する必要があります。
Is the second molar more important than other teeth? — **The literature found for this card does not rank teeth by importance, so this card makes no such claim [F22].** What can be said are verifiable facts: occlusal force distribution is greatest at the molar region, ahead of the premolar and anterior regions (small-sample measurement) [F15]; people with fewer posterior occluding pairs showed chewing performance 28% to 39% lower [F16]; and about 23.07% of people have at least one congenitally absent wisdom tooth, for whom the second molar is the functional terminal tooth on that side [F20]. What role a given tooth plays in your mouth must be assessed by a dentist against your own occlusion and any missing teeth.

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km 編輯部・《Which teeth are the molars? And why is the second molar the one people ask about?｜證據鏈》・IDAEO 知識庫・2026-08-13・https://km.idaeo.ai/post/reports/dental-molar-anatomy-evidence

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更新 2026-08-13T14:17:27.384Z · server-rendered · four-language · IDAEO 知識庫