Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (774 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
One of the eight permanent teeth, two on either side in each jaw, between the canines (cuspid) and the molars (molar), serving for grinding and crushing food. The upper have two cusps (bicuspid) but the lower have one to three. (Jablonski, Dictionary of Dentistry, 1992, p822)
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Bicuspids; Premolar; Premolars.
Where it fits in the MeSH classification
- Broader topics
- Tooth
Related concepts
- Cuspid
- Molar
Research landscape
PubMed indexes 12,927 records tagged with the MeSH heading “Bicuspid” (counts retrieved 2026-10-31). 1,866 of them (14.4%) were published from 2020 onward, and the busiest period so far is through 1999 with 4,377 records.
Reviews account for 400 records (3.1%) and meta-analyses for 51. Randomized controlled trials number 762 (5.9%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 4,377 |
| 2000-2009 | 3,080 |
| 2010-2019 | 3,604 |
| 2020 onward | 1,866 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 400 | 3.1% |
| Meta-analyses | 51 | 0.4% |
| Randomized controlled trials | 762 | 5.9% |
Method: PubMed query "Bicuspid"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-31.
Reading the evidence in anatomy and physiology
Anatomy describes how body structures are built and physiology describes how they normally work, so most findings here are descriptive or mechanistic rather than evidence about treatment. Much of what is known comes from dissection, imaging, tissue studies and experiments in animals, and measurements in healthy volunteers can differ from those in people with disease or at different ages. Normal ranges vary between individuals and populations. Check whether a result was measured in people or in another species, the age and health of the participants, and the method used.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Treatment outcome and efficacy of an aligner technique--regarding incisor torque, premolar derotation and molar distalization | 2014 | Research article Design not recorded in structured metadata | 266 | cc by PMID 24923279 · DOI · PMC4068978 |
| Hypodontia: An Update on Its Etiology, Classification, and Clinical Management | 2017 | Review article Design not recorded in structured metadata | 155 | cc by PMID 28401166 · DOI · PMC5376450 |
| Cone-beam computed tomography study of root and canal morphology of mandibular premolars in a western Chinese population | 2012 | Research article Design not recorded in structured metadata | 68 | cc by PMID 22817397 · DOI · PMC3412166 |
| Comparative analysis of postoperative mechanical behavior of immature premolars: apexification vs regeneration | 2026 | Research article Design not recorded in structured metadata | 0 | cc by PMID 41845157 · DOI · PMC13631037 |
Treatment outcome and efficacy of an aligner technique--regarding incisor torque, premolar derotation and molar distalization [1]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundThe aim of this study was to investigate the efficacy of orthodontic treatment using the Invisalign® system.
- Closing excerpt
- The staging (movement/aligner) and the total amount of planned movement have an significant impact on treatment efficacy.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (240 words)
BackgroundThe aim of this study was to investigate the efficacy of orthodontic treatment using the Invisalign® system. Particularly, we analyzed the influence of auxiliaries (Attachment/Power Ridge) as well as the staging (movement per aligner) on treatment efficacy.MethodsWe reviewed the tooth movements of 30 consecutive patients who required orthodontic treatment with Invisalign®. In all patients, one of the following tooth movements was performed: (1) Incisor Torque >10°, (2) Premolar derotation >10° (3) Molar distalization >1.5 mm. The groups (1)-(3) were subdivided: in the first subgroup (a) the movements were supported with the use of an attachment, while in the subgroup (b) no auxiliaries were used (except incisor torque, in which Power Ridges were used). All tooth movements were performed in a split-mouth design. To analyze the clinical efficacy, pre-treatment and final plaster cast models were laser-scanned and the achieved tooth movement was determined by way of a surface/surface matching algorithm. The results were compared with the amount of tooth movement predicted by ClinCheck®.ResultsThe overall mean efficacy was 59% (SD = 0.2). The mean accuracy for upper incisor torque was 42% (SD = 0.2). Premolar derotation showed the lowest accuracy with approximately 40% (SD = 0.3). Distalization of an upper molar was the most effective movement, with efficacy approximately 87% (SD = 0.2).ConclusionIncisor torque, premolar derotation and molar distalization can be performed using Invisalign® aligners. The staging (movement/aligner) and the total amount of planned movement have an significant impact on treatment efficacy.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 24923279 · DOI · PMC4068978
Hypodontia: An Update on Its Etiology, Classification, and Clinical Management [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Hypodontia, or tooth agenesis, is the most prevalent craniofacial malformation in humans.
- Closing excerpt
- Hence, the identification of genetic and environmental factors may be particularly useful in the early prediction of this condition and the development of prevention strategies and novel treatments in the future.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (148 words)
Hypodontia, or tooth agenesis, is the most prevalent craniofacial malformation in humans. It may occur as part of a recognised genetic syndrome or as a nonsyndromic isolated trait. Excluding third molars, the reported prevalence of hypodontia ranges from 1.6 to 6.9%, depending on the population studied. Most affected individuals lack only one or two teeth, with permanent second premolars and upper lateral incisors the most likely to be missing. Both environmental and genetic factors are involved in the aetiology of hypodontia, with the latter playing a more significant role. Hypodontia individuals often present a significant clinical challenge for orthodontists because, in a number of cases, the treatment time is prolonged and the treatment outcome may be compromised. Hence, the identification of genetic and environmental factors may be particularly useful in the early prediction of this condition and the development of prevention strategies and novel treatments in the future.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 28401166 · DOI · PMC5376450
Cone-beam computed tomography study of root and canal morphology of mandibular premolars in a western Chinese population [3]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundTraditional radiography is limited in its ability to give reliable information on the number and morphology of root canals.
- Closing excerpt
- CBCT scanning can be used in the management of mandibular premolars with complex canal morphology.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (211 words)
BackgroundTraditional radiography is limited in its ability to give reliable information on the number and morphology of root canals. The application of cone-beam computed tomography (CBCT) provides a non-invasive three-dimensional confirmatory diagnosis as a complement to conventional radiography. The aim of this study was to evaluate the root and canal morphology of mandibular premolars in a western Chinese population using CBCT scanning.MethodsThe sample included 149 CBCT images comprising 178 mandibular first premolars and 178 second premolars. The tooth position, number of roots and canals, and canal configuration according to Vertucci's classification were recorded.ResultsThe results showed that 98% of mandibular first premolars had one root and 2% had two roots; 87.1% had one canal, 11.2% had two canals and 0.6% had three canals. The prevalence of C-shaped canals was 1.1%. All mandibular second premolars had one root; 97.2% had one canal and 2.2% had two canals. The prevalence of C-shaped canals was 0.6%.ConclusionsThe prevalence of multiple canals in mandibular first premolars was mainly of Type V, and mandibular second premolars had a low rate of canal variation in this western Chinese population. Root canal bifurcation occurred at the middle or apical third in most bicanal mandibular premolars. CBCT scanning can be used in the management of mandibular premolars with complex canal morphology.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 22817397 · DOI · PMC3412166
Comparative analysis of postoperative mechanical behavior of immature premolars: apexification vs regeneration [4]
Abstract reading summary — source excerpts
- Opening excerpt
- To compare the mechanical behavior of lower premolars with incomplete root formation treated by apexification and regeneration and assess revascularization's impact on dentin thickness using finite element analysis.
- Closing excerpt
- Revascularization reduced stress concentration in the periradicular tissues, whereas apexification resulted in lower tensile stress in coronal dentin.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (175 words)
To compare the mechanical behavior of lower premolars with incomplete root formation treated by apexification and regeneration and assess revascularization's impact on dentin thickness using finite element analysis. A mandibular bone model was obtained from a computed tomography scan and modeled using the CAD Rhinoceros 7.0 software program. The models were composed of enamel, dentin, pulp, periodontal ligament, cortical bone, medullary bone, gutta-percha, MTA, blood clot, and composite resin. The study groups were: IT (Intact Tooth); AC (Accessed Tooth); R (revascularization); and AX (apexification). After modeling the structures, the geometries were exported to the Ansys 13.0 finite element analysis software program. The models were submitted to loads of 200 N on the distal sulcus of the occlusal surface. The loading was directed at 45° to the occlusal plane. The results were calculated and qualitatively analyzed using displacement maps and maximum principal stress. The apexification models supported lower compressive and tensile stresses when compared to the revascularization models. Revascularization reduced stress concentration in the periradicular tissues, whereas apexification resulted in lower tensile stress in coronal dentin.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41845157 · DOI · PMC13631037
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Cementogenesis reviewed: a comparison between human premolars and rodent molars [5]
- Research article Maxillary canine-first premolar transposition, associated dental anomalies and genetic basis [6]
- Research article The root and root canal morphology of the human mandibular first premolar: a literature review [7]
- Research article Critical hemorrhage in the floor of the mouth during implant placement in the first mandibular premolar position: a case report [8]
- Research article The root and root canal morphology of the human mandibular second premolar: a literature review [9]
- Research article The esthetic outcome of autotransplanted premolars replacing maxillary incisors [10]
References
- Simon M, Keilig L, Schwarze J, Jung BA, Bourauel C. Treatment outcome and efficacy of an aligner technique--regarding incisor torque, premolar derotation and molar distalization. . 2014. PMID 24923279 · DOI · PMC4068978
- Al-Ani AH, Antoun JS, Thomson WM, Merriman TR, Farella M. Hypodontia: An Update on Its Etiology, Classification, and Clinical Management. . 2017. PMID 28401166 · DOI · PMC5376450
- Yu X, Guo B, Li KZ, Zhang R, Tian YY, Wang H, et al.. Cone-beam computed tomography study of root and canal morphology of mandibular premolars in a western Chinese population. . 2012. PMID 22817397 · DOI · PMC3412166
- da Silva AC, de Barros Faria Júnior FC, Guerrero GG, Borges ALS, Valera MC. Comparative analysis of postoperative mechanical behavior of immature premolars: apexification vs regeneration. . 2026. PMID 41845157 · DOI · PMC13631037
- Bosshardt DD, Schroeder HE. Cementogenesis reviewed: a comparison between human premolars and rodent molars. Anat Rec. 1996. PMID 8769668 · DOI
- Peck L, Peck S, Attia Y. Maxillary canine-first premolar transposition, associated dental anomalies and genetic basis. Angle Orthod. 1993. PMID 8498708 · DOI
- Cleghorn BM, Christie WH, Dong CC. The root and root canal morphology of the human mandibular first premolar: a literature review. J Endod. 2007. PMID 17437863 · DOI
- Kalpidis CD, Konstantinidis AB. Critical hemorrhage in the floor of the mouth during implant placement in the first mandibular premolar position: a case report. Implant Dent. 2005. PMID 15968182 · DOI
- Cleghorn BM, Christie WH, Dong CC. The root and root canal morphology of the human mandibular second premolar: a literature review. J Endod. 2007. PMID 17931927 · DOI
- Czochrowska EM, Stenvik A, Zachrisson BU. The esthetic outcome of autotransplanted premolars replacing maxillary incisors. Dent Traumatol. 2002. PMID 12427198 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-31.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.