# Selection of Denture Teeth > Denture teeth selection for BDS Prosthodontics: acrylic versus porcelain, mould and shade, Berry's ratio, SPA concept, cusp angles and exam picks. - Canonical URL: https://prepelephant.com/topics/bds/prosthodontics/denture-teeth-selection - Exam / course: BDS · Subject: Prosthodontics - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Selection of Denture Teeth", PrepElephant, https://prepelephant.com/topics/bds/prosthodontics/denture-teeth-selection ## Direct answer Two material choices — acrylic versus porcelain — and four form choices — mould, shade, cusp angle and arrangement — decide denture teeth. Acrylic teeth bond chemically to the base, are light, quiet and kind to ridges, and equilibrate easily, but wear; porcelain resists wear, but is heavy, brittle, clicks and depends on mechanical retention (diatoric holes or pins) because no chemical bond forms. Size is steered by pre-extraction records and classical biometric hints — Berry's ratio makes the maxillary central incisor about one-sixteenth of the bizygomatic width — while Frush and Fisher's dentogenic concept individualises character through sex, personality and age. Cusp angle follows the occlusal scheme: anatomic (roughly 30-45 degrees), semi-anatomic (about 10-20 degrees) or zero-degree non-anatomic teeth, the last paired with lingualised occlusion for flat, resorbed ridges. ## What you must remember - **Acrylic versus porcelain, the five-marker:** bond to base, weight, brittleness, click, wear, adjustability, rebasability — acrylic wins on adaptation and repair, porcelain on durability and aesthetics over time. - **Diatorics:** the retention holes cut into porcelain teeth's ridge laps, their answer to having no chemical bond with the base. - **Berry's biometric ratio:** the width of the maxillary central incisor relates to bizygomatic width as about 1:16 — classical, quoted in every Indian textbook, best used as a starting estimate rather than a rule. - **Williams' face-form theory:** inverted face form (square, tapering, ovoid) matching tooth form — historically dominant, aesthetically influential, and weakly supported by modern evidence, so present it as a classical guide. - **Dentogenic concept (Frush and Fisher):** sex, personality and age (SPA) individualise the mould — feminine teeth finer and more rounded, masculine squarer and larger; age adds wear facets and darker shade. - **Cusp angles:** anatomic teeth around 30-45 degrees for balanced occlusion on good ridges; semi-anatomic about 10-20 degrees as compromise; zero-degree (monoplane) for flat ridges and gross ridge resorption, often with lingualised occlusion where maxillary cusps occlude against a flat mandibular table. - **Pre-extraction records:** previous dentures, extracted teeth, photographs, study casts and the patient's own description — always better than any ratio. ## Selecting teeth for a 55-year-old teacher Work the chairside sequence. Begin with records: her previous denture gives mould number and shade; a smiling photograph from a decade ago shows how much tooth the lip displayed. Apply Berry's ratio for a first estimate of central width, then confirm against the mould guide — the six anteriors should just fill the width between the corners of the mouth at rest. Choose shade under natural daylight against skin, hair and eye: a 55-year-old needs a slightly darker, less saturated shade, and personality argues against stark white. Adjust character per the SPA concept — softened incisal edges, a hint of wear. For posterior teeth, her ridges are moderate, so semi-anatomic teeth with a balanced scheme serve; had the ridges been flat, a zero-degree or lingualised arrangement would protect the ridges from horizontal shear. Record mould, shade, brand and any characterisation on the laboratory authorisation — unwritten selection is no selection. ## How the exam frames it The guaranteed question is acrylic versus porcelain teeth as a five-mark comparison, and the marks sit in specifics: chemical bond versus diatoric retention, weight, click, wear, adjustability and rebasability. The MCQ bank leans on names — Berry's 1:16 ratio, Williams' face-form theory, Frush and Fisher's dentogenic concept — and examiners enjoy asking which of these has the weakest scientific support, expecting the candidate to distinguish classical teaching from validated science. A recurring viva trap asks why acrylic teeth dominate Indian practice when porcelain is more durable: the expected reasoning runs through ridge kindness, weight for atrophic mandibles, rebasing compatibility and repair rather than any single factor. Boards also ask cusp angle by ridge condition — good ridges take anatomic teeth for balanced occlusion, resorbed ridges take zero-degree or lingualised schemes to reduce horizontal forces — and reward the candidate who links tooth selection to ridge prognosis rather than treating it as a cosmetic exercise. ## Frequently asked questions ### How do porcelain denture teeth attach to the base without chemical bonding? Through mechanical retention — diatoric holes or pins in the ridge lap into which the acrylic flows during processing. ### What is Berry's biometric ratio? The classical relation of the maxillary central incisor width to the bizygomatic width, approximately 1:16, used as a starting estimate for mould selection. ### What does the dentogenic concept add to tooth selection? Frush and Fisher's sex-personality-age (SPA) framework individualises standard moulds — softer contours for feminine personalities, wear facets and darker shades with age. ### Which cusp angle suits severely resorbed ridges? Zero-degree non-anatomic teeth, often arranged in a lingualised scheme, minimise horizontal shear that atrophic ridges cannot resist. ### Why are acrylic teeth preferred on a badly resorbed mandibular ridge? They are lighter, dampen force through the base, can be rebased and readjusted easily, and avoid the chipping and click of porcelain on a mobile, atrophic foundation.